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1

Reduction of reactive oxygen species ameliorates metabolism-secretion coupling in islets of diabetic GK rats by suppressing lactate overproduction.  

PubMed

We previously demonstrated that impaired glucose-induced insulin secretion (IS) and ATP elevation in islets of Goto-Kakizaki (GK) rats, a nonobese model of diabetes, were significantly restored by 30-60-min suppression of endogenous reactive oxygen species (ROS) overproduction. In this study, we investigated the effect of a longer (12 h) suppression of ROS on metabolism-secretion coupling in ?-cells by exposure to tempol, a superoxide (O2(-)) dismutase mimic, plus ebselen, a glutathione peroxidase mimic (TE treatment). In GK islets, both H2O2 and O2(-) were sufficiently reduced and glucose-induced IS and ATP elevation were improved by TE treatment. Glucose oxidation, an indicator of Krebs cycle velocity, also was improved by TE treatment at high glucose, whereas glucokinase activity, which determines glycolytic velocity, was not affected. Lactate production was markedly increased in GK islets, and TE treatment reduced lactate production and protein expression of lactate dehydrogenase and hypoxia-inducible factor 1? (HIF1?). These results indicate that the Warburg-like effect, which is characteristic of aerobic metabolism in cancer cells by which lactate is overproduced with reduced linking to mitochondria metabolism, plays an important role in impaired metabolism-secretion coupling in diabetic ?-cells and suggest that ROS reduction can improve mitochondrial metabolism by suppressing lactate overproduction through the inhibition of HIF1? stabilization. PMID:23349483

Sasaki, Mayumi; Fujimoto, Shimpei; Sato, Yuichi; Nishi, Yuichi; Mukai, Eri; Yamano, Gen; Sato, Hiroki; Tahara, Yumiko; Ogura, Kasane; Nagashima, Kazuaki; Inagaki, Nobuya

2013-01-24

2

PKC? Sensitizes Neuroblastoma Cells to L-Buthionine-Sulfoximine and Etoposide Inducing Reactive Oxygen Species Overproduction and DNA Damage  

PubMed Central

Neuroblastoma is a type of pediatric cancer. The sensitivity of neuroblastoma (NB) cancer cells to chemotherapy and radiation is inhibited by the presence of antioxidants, such as glutathione (GSH), which is crucial in counteracting the endogenous production of reactive oxygen species (ROS). We have previously demonstrated that cells depleted of GSH undergo apoptosis via oxidative stress and Protein kinase C (PKC) ? activation. In the present study, we transfected PKC? in NB cells resistant to oxidative death induced by L-buthionine-S,R-sulfoximine (BSO), a GSH-depleting agent. Cell responses, in terms of ROS production, apoptosis and DNA damage were evaluated. Moreover, PKC? activation was monitored by analyzing the phosphorylation status of threonine 505 residue, carrying out PKC activity assay and investigating the subcellular localization of the kinase. The cell responses obtained in BSO-resistant cells were also compared with those obtained in BSO-sensitive cells subjected to the same experimental protocol. Our results demonstrate, for the first time, that PKC? induces DNA oxidation and ROS overproduction leading to apoptosis of BSO-resistant NB cells and potentiates the cytotoxic effects induced by BSO in sensitive cells. Moreover, PKC? overexpression enhances the sensitivity of NB cells to etoposide, a well-characterised drug, commonly used in neuroblastoma therapy. Altogether our data provide evidence of a pro-oxidant role of PKC? that might be exploited to design new therapeutic strategies aimed at selective killing of cancer cells and overcoming drug resistance. However, it becomes evident that a more detailed understanding of ROS-mediated signaling in cancer cells is necessary for the development of redox-modulated therapeutic approaches.

Ricciarelli, Roberta; Passalacqua, Mario; Nitti, Mariapaola; Zingg, Jean-Marc; Marinari, Umberto M.; Pronzato, Maria A.; Domenicotti, Cinzia

2011-01-01

3

NADPH oxidase-derived overproduction of reactive oxygen species impairs postischemic neovascularization in mice with type 1 diabetes.  

PubMed

We hypothesized that diabetes-induced oxidative stress may affect postischemic neovascularization. The response to unilateral femoral artery ligation was studied in wild-type or gp91(phox)-deficient control or type 1 diabetic mice or in animals treated with the anti-oxidant N-acetyl-l-cysteine (NAC) or with in vivo electrotransfer of a plasmid encoding dominant-negative Rac1 (50 microg) for 21 days. Postischemic neovascularization was reduced in diabetic mice in association with down-regulated vascular endothelial growth factor-A protein levels. In diabetic animals vascular endothelial growth factor levels and postischemic neovascularization were restored to nondiabetic levels by the scavenging of reactive oxygen species (ROS) by NAC administration or the inhibition of ROS generation by gp91(phox) deficiency or by administration of dominant-negative Rac1. Finally, diabetes reduced the ability of adherent bone marrow-derived mononuclear cells (BM-MNCs) to differentiate into endothelial progenitor cells. Treatment with NAC (3 mmol/L), apocynin (200 micromol/L), or the p38MAPK inhibitor LY333351 (10 micromol/L) up-regulated the number of endothelial progenitor cell colonies derived from diabetic BM-MNCs by 1.5-, 1.6-, and 1.5-fold, respectively (P < 0.05). In the ischemic hindlimb model, injection of diabetic BM-MNCs isolated from NAC-treated or gp91(phox)-deficient diabetic mice increased neovascularization by approximately 1.5-fold greater than untreated diabetic BM-MNCs (P < 0.05). Thus, inhibition of NADPH oxidase-derived ROS overproduction improves the angiogenic and vasculogenic processes and restores postischemic neovascularization in type 1 diabetic mice. PMID:16877369

Ebrahimian, Téni G; Heymes, Christophe; You, Dong; Blanc-Brude, Olivier; Mees, Barend; Waeckel, Ludovic; Duriez, Micheline; Vilar, José; Brandes, Ralph P; Levy, Bernard I; Shah, Ajay M; Silvestre, Jean-Sébastien

2006-08-01

4

PKCdelta Sensitizes Neuroblastoma Cells to L-Buthionine-Sulfoximine and Etoposide Inducing Reactive Oxygen Species Overproduction and DNA Damage  

Microsoft Academic Search

Neuroblastoma is a type of pediatric cancer. The sensitivity of neuroblastoma (NB) cancer cells to chemotherapy and radiation is inhibited by the presence of antioxidants, such as glutathione (GSH), which is crucial in counteracting the endogenous production of reactive oxygen species (ROS). We have previously demonstrated that cells depleted of GSH undergo apoptosis via oxidative stress and Protein kinase C

Barbara Marengo; Chiara de Ciucis; Roberta Ricciarelli; Mario Passalacqua; Mariapaola Nitti; Jean-Marc Zingg; Umberto M. Marinari; Maria A. Pronzato; Cinzia Domenicotti; Joseph Najbauer

2011-01-01

5

During the stationary growth phase, Yarrowia lipolytica prevents the overproduction of reactive oxygen species by activating an uncoupled mitochondrial respiratory pathway.  

PubMed

In the branched mitochondrial respiratory chain from Yarrowia lipolytica there are two alternative oxido-reductases that do not pump protons, namely an external type II NADH dehydrogenase (NDH2e) and the alternative oxidase (AOX). Direct electron transfer between these proteins is not coupled to ATP synthesis and should be avoided in most physiological conditions. However, under low energy-requiring conditions an uncoupled high rate of oxygen consumption would be beneficial, as it would prevent overproduction of reactive oxygen species (ROS). In mitochondria from high energy-requiring, logarithmic-growth phase cells, most NDH2e was associated to cytochrome c oxidase and electrons from NADH were channeled to the cytochromic pathway. In contrast, in the low energy requiring, late stationary-growth phase, complex IV concentration decreased, the cells overexpressed NDH2e and thus a large fraction of this enzyme was found in a non-associated form. Also, the NDH2e-AOX uncoupled pathway was activated and the state IV external NADH-dependent production of ROS decreased. Association/dissociation of NDH2e to/from complex IV is proposed to be the switch that channels electrons from external NADH to the coupled cytochrome pathway or allows them to reach an uncoupled, alternative, ??-independent pathway. PMID:22138628

Guerrero-Castillo, Sergio; Cabrera-Orefice, Alfredo; Vázquez-Acevedo, Miriam; González-Halphen, Diego; Uribe-Carvajal, Salvador

2011-11-22

6

Enhanced reactive oxygen species scavenging by overproduction of superoxide dismutase and catalase delays postharvest physiological deterioration of cassava storage roots.  

PubMed

Postharvest physiological deterioration (PPD) of cassava (Manihot esculenta) storage roots is the result of a rapid oxidative burst, which leads to discoloration of the vascular tissues due to the oxidation of phenolic compounds. In this study, coexpression of the reactive oxygen species (ROS)-scavenging enzymes copper/zinc superoxide dismutase (MeCu/ZnSOD) and catalase (MeCAT1) in transgenic cassava was used to explore the intrinsic relationship between ROS scavenging and PPD occurrence. Transgenic cassava plants integrated with the expression cassette p54::MeCu/ZnSOD-35S::MeCAT1 were confirmed by Southern-blot analysis. The expression of MeCu/ZnSOD and MeCAT1 was verified by quantitative reverse transcription-polymerase chain reaction and enzymatic activity analysis both in the leaves and storage roots. Under exposure to the ROS-generating reagent methyl viologen or to hydrogen peroxide (H2O2), the transgenic plants showed higher enzymatic activities of SOD and CAT than the wild-type plants. Levels of malondialdehyde, chlorophyll degradation, lipid peroxidation, and H2O2 accumulation were dramatically reduced in the transgenic lines compared with the wild type. After harvest, the storage roots of transgenic cassava lines show a delay in their PPD response of at least 10 d, accompanied by less mitochondrial oxidation and H2O2 accumulation, compared with those of the wild type. We hypothesize that this is due to the combined ectopic expression of Cu/ZnSOD and CAT leading to an improved synergistic ROS-scavenging capacity of the roots. Our study not only sheds light on the mechanism of the PPD process but also develops an effective approach for delaying the occurrence of PPD in cassava. PMID:23344905

Xu, Jia; Duan, Xiaoguang; Yang, Jun; Beeching, John R; Zhang, Peng

2013-01-23

7

Overproduction of free radical species in embryonal cells exposed to low intensity radiofrequency radiation.  

PubMed

Aim: Long-term exposure of humans to low intensity radiofrequency electromagnetic radiation (RF-EMR) leads to a statistically significant increase in tumor incidence. Mechanisms of such the effects are unclear, but features of oxidative stress in living cells under RF-EMR exposure were previously reported. Our study aims to assess a production of initial free radical species, which lead to oxidative stress in the cell. Materials and Methods: Embryos of Japanese quails were exposed in ovo to extremely low intensity RF-EMR of GSM 900 MHz (0.25 µW/cm2) during 158-360 h discontinuously (48 c - ON, 12 c - OFF) before and in the initial stages of development. The levels of superoxide (O2·-), nitrogen oxide (NO·), thiobarbituric acid reactive substances (TBARS), 8-oxo-2'-deoxyguanosine (8-oxo-dG) and antioxidant enzymes' activities were assessed in cells/tissues of 38-h, 5- and 10-day RF-EMR exposed and unexposed embryos. Results: The exposure resulted in a significant persistent overproduction of superoxide and nitrogen oxide in embryo cells during all period of analyses. As a result, significantly increased levels of TBARS and 8-oxo-dG followed by significantly decreased levels of superoxide dismutase and catalase activities were developed in the exposed embryo cells. Conclusion: Exposure of developing quail embryos to extremely low intensity RF-EMR of GSM 900 MHz during at least one hundred and fifty-eight hours leads to a significant overproduction of free radicals/reactive oxygen species and oxidative damage of DNA in embryo cells. These oxidative changes may lead to pathologies up to oncogenic transformation of cells. PMID:24084462

Burlaka, A; Tsybulin, O; Sidorik, E; Lukin, S; Polishuk, V; Tsehmistrenko, S; Yakymenko, I

2013-09-01

8

[Reactive nitrogen and oxygen species].  

PubMed

Reactive nitrogen species (RNS) and reactive oxygen species (ROS) are mainly free radicals which including non-paired electrons. They are constantly formed as side products of biological reactions. They are also generated directly and indirectly by the cells which were exposed to environmental stress, i.e., UV radiation, ionizing radiation, xenobioticts, light-absorbing compounds, e.g., porphyrines. These factors, which are a source of free radicals, initiate a significant signaling cascade inducing many changes in cells, such as cancerogenic transformation or cell death. Cells protect themselves against oxidative stress by means of antioxidative enzymes and compounds which in their structure have redox sensitive spots. PMID:19928666

Puzanowska-Tarasiewicz, Helena; Ku?micka, Ludmi?a; Tarasiewicz, Miros?aw

2009-10-01

9

Reactive oxygen species and photobiostimulation  

NASA Astrophysics Data System (ADS)

The biostimulative effects exerted by various low power lasers in the visible and near IR might be a consequence of reactive oxygen species (ROS) production. Although high concentration of ROS leads to cell death, low and controlled concentrations may play an important role in cell activation. It is assumed that the light which is absorbed by endogenous photosensitizers induces the formation of minute amounts of ROS which are beneficial for the cell. In the present review we summarize recent experimental data providing evidence for ROS involvement in photobiostimulation of skin and sperm cells.

Lubart, Rachel; Friedman, Harry; Grossman, Nili; Cohen, Natalie; Breitbart, Haim

1997-12-01

10

Reactive oxygen species in periodontitis  

PubMed Central

Recent epidemiological studies reveal that more than two-third of the world's population suffers from one of the chronic forms of periodontal disease. The primary etiological agent of this inflammatory disease is a polymicrobial complex, predominantly Gram negative anaerobic or facultative bacteria within the sub-gingival biofilm. These bacterial species initiate the production of various cytokines such as interleukin-8 and TNF-?, further causing an increase in number and activity of polymorphonucleocytes (PMN) along with these cytokines, PMNs also produce reactive oxygen species (ROS) superoxide via the respiratory burst mechanism as the part of the defence response to infection. ROS just like the interleukins have deleterious effects on tissue cells when produced in excess. To counter the harmful effects of ROS, human body has its own defence mechanisms to eliminate them as soon as they are formed. The aim of this review is to focus on the role of different free radicals, ROS, and antioxidants in the pathophysiology of periodontal tissue destruction.

Dahiya, Parveen; Kamal, Reet; Gupta, Rajan; Bhardwaj, Rohit; Chaudhary, Karun; Kaur, Simerpreet

2013-01-01

11

Reactive oxygen species in cardiovascular disease.  

PubMed

Based on the "free radical theory" of disease, researchers have been trying to elucidate the role of oxidative stress from free radicals in cardiovascular disease. Considerable data indicate that reactive oxygen species and oxidative stress are important features of cardiovascular diseases including atherosclerosis, hypertension, and congestive heart failure. However, blanket strategies with antioxidants to ameliorate cardiovascular disease have not generally yielded favorable results. However, our understanding of reactive oxygen species has evolved to the point at which we now realize these species have important roles in physiology as well as pathophysiology. Thus, it is overly simplistic to assume a general antioxidant strategy will yield specific effects on cardiovascular disease. Indeed, there are several sources of reactive oxygen species that are known to be active in the cardiovascular system. This review addresses our understanding of reactive oxygen species sources in cardiovascular disease and both animal and human data defining how reactive oxygen species contribute to physiology and pathology. PMID:21627987

Sugamura, Koichi; Keaney, John F

2011-05-15

12

ESR of Adsorbed Oxygen Species  

Microsoft Academic Search

Although the catalytic oxidation of inorganic molecules, as well as the oxidation and oxidative dehydrogenation of hydrocarbons, has been the subject of extensive research, the role of oxygen in surface reactions remains uncertain. Various forms of adsorbed oxygen have been proposed on the basis of kinetic and adsorption data or electrical conductivity measurements; yet, very little direct spectroscopic evidence is

J. H. Lunsford

1974-01-01

13

Reactive oxygen species: the unavoidable environmental insult?  

Microsoft Academic Search

Reactive oxygen species (ROS) are generated by a variety of sources from the environment (e.g., photo-oxidations and emissions) and normal cellular functions (e.g., mitochondrial metabolism and neutrophil activation). ROS include free radicals (e.g., superoxide and hydroxyl radicals), nonradical oxygen species (e.g., hydrogen peroxide and peroxynitrite) and reactive lipids and carbohydrates (e.g., ketoaldehydes, hydroxynonenal). Oxidative damage to DNA can occur by

R. W Gracy; J. M Talent; Y Kong; C. C Conrad

1999-01-01

14

Stress Signaling III: Reactive Oxygen Species (ROS)  

Microsoft Academic Search

\\u000a Previously regarded merely as damaging agents, reactive oxygen species (ROS) are now understood as important signal molecules\\u000a vital to normal plant growth. This tutorial review covers the emerging view of ROS signaling networks from ROS production\\u000a to specific outputs. The chemical nature of individual reactive oxygen species, their site of the production, control of ROS\\u000a accumulation via scavenging and detoxification,

Mikael Brosché; Kirk Overmyer; Michael Wrzaczek; Jaakko Kangasjärvi; Saijaliisa Kangasjärvi

15

[Hemoglobin--source of reactive oxygen species].  

PubMed

Erythrocytes are especially vulnerable to reactive oxygen species because of their direct role in oxygen transport. Moreover, hemoglobin contains iron ions (Fe²?), which catalyze both the Fenton reaction and lipid peroxidation. Reactive oxygen species in erythrocytes are also generated through nonenzymatic and enzymatic processes of heme degradation. The nonenzymatic process of heme degradation is initiated by e.g. hydrogen peroxide, whereas the process of enzymatic degradation is under the influence of heme oxygenase. In both cases biliverdin, carbon monoxide (CO) and iron ions (Fe²?) are generated. These products of heme degradation can initialize the oxidative processes within erythrocytes, but at low concentrations exhibit cytoprotective properties. PMID:23619220

Zapora, Ewa; Jarocka, Iwona

2013-03-29

16

Signaling of Reactive Oxygen and Nitrogen Species in Diabetes Mellitus  

PubMed Central

Disorder of physiological signaling functions of reactive oxygen species(ROS) superoxide and hydrogen peroxide and reactive nitrogen species (RNS) nitric oxide and peroxynitrite is an important feature of diabetes mellitus type 1 and type 2. It is now known that hyperglycemic conditions of cells are associated with the enhanced levels of ROS mainly generated by mitochondria and NADPH oxidase. It has been established that ROS stimulate many enzymatic cascades under normal physiological conditions, but hyperglycemia causes ROS overproduction and the deregulation of ROS signaling pathways initiating the development of diabetes mellitus. On the other hand the deregulation of RNS signaling leads basically to a decrease in NO formation with subsequent damaging disorders. In the present work we will consider the pathological changes of ROS and RNS signaling in enzyme/gene regulated processes catalyzed by protein kinases C and B (Akt/B), phosphatidylinositol 3?-kinase (PI3-kinase), extracellular signal-regulated kinase 1/2 (ERK1/2) and some others. Furthermore we will discuss a particularly important role of several ROS-regulated genes and adapter proteins such as the p66shc, FOXO3a and Sirt2. The effects of low and high ROS levels in diabetes will be also considered. Thus the regulation of damaging ROS levels in diabetes by antioxidants and free radical scavengers must be one of promising treatment of this disease, however, because of the inability of traditionalantioxidative vitamin E and C to interact with superoxide and hydrogen peroxide,new free radical scavengers such as flavonoids, quinones and synthetic mimetics of superoxide dismutase (SOD) should be intensively studied.

Afanas'ev, Igor

2010-01-01

17

Reactive oxygen species and sperm cells  

Microsoft Academic Search

There is a dynamic interplay between pro- and anti-oxidant substances in human ejaculate. Excessive reactive oxygen species (ROS) generation can overwhelm protective mechanism and initiate changes in lipid and\\/or protein layers of sperm plasma membranes. Additionally, changes in DNA can be induced. The essential steps of lipid peroxidation have been listed as well as antioxidant substances of semen. A variety

Dorota Sanocka; Maciej Kurpisz

2004-01-01

18

Formation and Detoxification of Reactive Oxygen Species  

ERIC Educational Resources Information Center

A model of reactive oxygen species metabolism is proposed as a laboratory exercise for students. The superoxide ion in this model is generated during the reaction of oxidation of xanthine, catalyzed by xanthine oxidase. The effect of catalase, superoxide dismutase, and allopurinol on superoxide ion generation and removal in this system is also…

Kuciel, Radoslawa; Mazurkiewicz, Aleksandra

2004-01-01

19

Reactive oxygen species in cardiovascular disease  

Microsoft Academic Search

Based on the “free radical theory” of disease, researchers have been trying to elucidate the role of oxidative stress from free radicals in cardiovascular disease. Considerable data indicate that reactive oxygen species and oxidative stress are important features of cardiovascular diseases including atherosclerosis, hypertension, and congestive heart failure. However, blanket strategies with antioxidants to ameliorate cardiovascular disease have not generally

Koichi Sugamura

2011-01-01

20

Formation and Detoxification of Reactive Oxygen Species  

ERIC Educational Resources Information Center

|A model of reactive oxygen species metabolism is proposed as a laboratory exercise for students. The superoxide ion in this model is generated during the reaction of oxidation of xanthine, catalyzed by xanthine oxidase. The effect of catalase, superoxide dismutase, and allopurinol on superoxide ion generation and removal in this system is also…

Kuciel, Radoslawa; Mazurkiewicz, Aleksandra

2004-01-01

21

[Organism defense against reactive oxygen species].  

PubMed

Reactive oxygen species (ROS) are constantly formed as side products of biological reactions in which electron transfer goes on. ROS include superoxide anion radical O2*, hydroxide radical *OH, hydrogensuperoxide radical HO2*, hydrogen peroxide and singlet oxygen. The maintenance of homeostasis at the redox level is particularly important for many biological processes such as: DNA synthesis, enzymes activation and regulation genes, regulation of cellular cycle and programmed death of the cell. Cells protect themselves against oxidative stress by means of antioxidants enzymes and compounds which in their structure have redox sensitive spots. PMID:20648768

Puzanowska-Tarasiewicz, Helena; Ku?micka, Ludmi?a; Tarasiewicz, Miros?aw

2009-01-01

22

[Reactive oxygen species and aging of organism].  

PubMed

The review is devoted for reactive oxygen species (ROS). Numerous processes of cellular oxidation proceed through the stage of free radicals. These radicals containing odd electrons are formed in the course of many biochemical reactions. As a result of aging, as well as action of various environmental factors, eg. ionizing radiation or different chemical compounds synthesis of free radicals increases, whereas the detoxication ability decreases. Free radicals: O(2-)*, *OH, ROO*, RO* and O3, H2O2, singlet oxygen may be removed by means of defence systems of living organism and antioxidants. PMID:20229716

Puzanowska-Tarasiewicz, Helena; Ku?micka, Ludmi?a; Tarasiewicz, Miros?aw

2009-01-01

23

Reactive Oxygen Species in Plant Cell Walls  

Microsoft Academic Search

Plant cell walls are dynamic structures composed of polysaccharides, phenolics, and proteins. The plant cell wall is important\\u000a not only for maintaining cell shape, but it also responds to endogenous and environmental clues through the release of signaling\\u000a molecules, such as H2O2, which may act following autocrine and paracrine pathways. However, the primary function of reactive oxygen species (ROS)\\u000a production

Alfonso Ros Barceló; V. Gómez Ros Laura

24

Reactive oxygen species, mitochondria, apoptosis and aging  

Microsoft Academic Search

In this paper, we shall review various antioxygen defense systems of the cell paying particular attention to those that prevent superoxide formation rather than scavenge already formed superoxide and its products. The role of uncoupled, decoupled and non-coupled respiration, mitochondrial pore, mitochondrion-linked apoptosis will be considered. Mitochondrial theory of aging will be regarded in context of reactive oxygen species-induced damage

S. Papa; V. P. Skulachev

1997-01-01

25

Reactive Oxygen Species in Cell Fate Decisions  

Microsoft Academic Search

Redox homeostasis is a function of the balance between the intracellular generation of reactive oxygen species (ROS) and the\\u000a cellular antioxidant defense systems. Therefore, the degree of oxidative stress is a direct outcome of the rate at which the\\u000a cells’ metabolic processes fuel ROS production and the efficiency with which the antioxidant machinery is able to deal with\\u000a the impending

Han-Ming Shen; Shazib Pervaiz

26

Reactive Oxygen Species in Growth and Development  

Microsoft Academic Search

The spatial control of cell growth is a central process in plant development. Reactive oxygen species (ROS) are important\\u000a regulators of cell and organ growth and are thought to operate by controlling the extensibility of the cell wall and modulating\\u000a intracellular signalling processes. By increasing elasticity of the wall they promote growth, and by cross-linking polymers\\u000a they increase rigidity and

Elizabeth Bell; Seiji Takeda; Liam Dolan

27

Agents capable of eliminating reactive oxygen species  

Microsoft Academic Search

Reactive oxygen species (ROS) such as superoxide anion, hydrogen peroxide, hydroxyl radical, and hypochlorous acid have been implicated in the pathogenesis of inflammation and tissue injury in colitis. To determine whether or not anti-ROS agents can decrease the severity of colitis, we evaluated the effects of three known anti-ROS agents: catalase, WR-2721, and Cu(II)2(3,5-DIPS)4 on acetic acid-induced colonic inflammation in

Ali Kesha Varzian; John Haydek; Ramin Zabihi; Manuel Doria; Michael D'Astice; John R. J. Sorenson

1992-01-01

28

Signal transduction by reactive oxygen species  

PubMed Central

Although historically viewed as purely harmful, recent evidence suggests that reactive oxygen species (ROS) function as important physiological regulators of intracellular signaling pathways. The specific effects of ROS are modulated in large part through the covalent modification of specific cysteine residues found within redox-sensitive target proteins. Oxidation of these specific and reactive cysteine residues in turn can lead to the reversible modification of enzymatic activity. Emerging evidence suggests that ROS regulate diverse physiological parameters ranging from the response to growth factor stimulation to the generation of the inflammatory response, and that dysregulated ROS signaling may contribute to a host of human diseases.

2011-01-01

29

Reactive oxygen species, water, photons and life.  

PubMed

Unique properties of oxygen and of the reactions with reactive oxygen species (ROS) participation are considered, the multiple ways of ROS generation and utilization are discussed in view of evidence for the absolute necessity of ROS for the normal vital activity. Many difficulties in the realization of the real role of ROS in vital activity are caused by the attitude to them only as to chemical substances, while they should be considered in the first place as the major participants of continuous flows of highly non-linear processes in which electron excited species emerge. These processes play a significant role in energy and informational flows in all the living systems. We suggest that the mechanisms of biological action of ROS are determined by the structural patterns (frequency-amplitude patterns of electron excited states generation and their relaxation) of the processes with ROS participation taking place in the aqueous environs. Energy released in such reactions is used as an activation energy for specific biochemical processes, for the continuous "pumping" of the non-equilibrium state of inter- and intracellular structural components, while the structural patterns of ROS reactions determine biochemical and physiological rhythmic modes. Special role of water in all these phenomena is discussed. From a broader perspective the processes with ROS participation emerging in water preceded and were the necessary condition for origination and evolution of organic living forms on Earth. PMID:21384328

Voeikov, Vladimir

30

Reactive Oxygen Species in Skeletal Muscle Signaling  

PubMed Central

Generation of reactive oxygen species (ROS) is a ubiquitous phenomenon in eukaryotic cells' life. Up to the 1990s of the past century, ROS have been solely considered as toxic species resulting in oxidative stress, pathogenesis and aging. However, there is now clear evidence that ROS are not merely toxic species but also—within certain concentrations—useful signaling molecules regulating physiological processes. During intense skeletal muscle contractile activity myotubes' mitochondria generate high ROS flows: this renders skeletal muscle a tissue where ROS hold a particular relevance. According to their hormetic nature, in muscles ROS may trigger different signaling pathways leading to diverging responses, from adaptation to cell death. Whether a “positive” or “negative” response will prevail depends on many variables such as, among others, the site of ROS production, the persistence of ROS flow or target cells' antioxidant status. In this light, a specific threshold of physiological ROS concentrations above which ROS exert negative, toxic effects is hard to determine, and the concept of “physiologically compatible” levels of ROS would better fit with such a dynamic scenario. In this review these concepts will be discussed along with the most relevant signaling pathways triggered and/or affected by ROS in skeletal muscle.

Barbieri, Elena; Sestili, Piero

2012-01-01

31

[The two faces of reactive oxygen species].  

PubMed

Oxidative stress has been implicated in playing a crucial role in aging and in the pathogeneses of a number of diseases, including neurodegenerative disorders such as Alzheimer's disease. Oxidative stress occurs due to an imbalance in prooxidant and antioxidant levels. Reactive oxygen species (ROS) are highly reactive and may modify and inactivate proteins, lipids, DNA, and RNA and induce cellular dysfunctions. To prevent free radical-induced cellular damage, the organism has developed a defense mechanism, the antioxidative system. This system includes antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), and glutathione reductase (GSSGR) and low-molecular antioxidants such as glutathion and plasma proteins. Glutathion plays a key role in maintaining the physiological balance between prooxidants and antioxidants. Plasma proteins can inhibit ROS generation and lipid peroxidation by chelating free transition metals. The major exogenous antioxidants are vitamins E, C, and A. PMID:18388851

Zab?ocka, Agnieszka; Janusz, Maria

2008-03-26

32

Reactive oxygen species and tumor metastasis.  

PubMed

The migration and invasion of cancer cells are the first steps in metastasis. Through a series of cellular responses, including cytoskeletal reorganization and degradation of the extracellular matrix, cancer cells are able to separate from the primary tumor and metastasize to distant locations in the body. In cancer cells, reactive oxygen species (ROS) play important roles in the migration and invasion of cells. Stimulation of cell surface receptors with growth factors and integrin assembly generates ROS, which relay signals from the cell surface to important signaling proteins. ROS then act within cells to promote migration and invasion. In this review, we collect recent evidence pointing towards the involvement of ROS in tumor metastasis and discuss the roles of ROS at different stages during the process of cancer cell migration, invasion and epithelial-mesenchymal transition. PMID:23456330

Lee, Doo Jae; Kang, Sang Won

2013-02-21

33

Reactive oxygen species enhance insulin sensitivity  

PubMed Central

SUMMARY Chronic reactive oxygen species (ROS) production by mitochondria may contribute to the development of insulin resistance, a primary feature of type 2 diabetes. In recent years it has become apparent that ROS generation in response to physiological stimuli such as insulin may also facilitate signaling by reversibly oxidizing and inhibiting protein tyrosine phosphatases (PTPs). Here we report that mice lacking one of the key enzymes involved in the elimination of physiological ROS, glutathione peroxidase 1 (Gpx1), were protected from high fat diet-induced insulin resistance. The increased insulin sensitivity in Gpx1?/? mice was attributed to insulin-induced phosphatidylinositol-3-kinase/Akt signaling and glucose uptake in muscle and could be reversed by the anti-oxidant N-acetylcysteine. Increased insulin signaling correlated with enhanced oxidation of the PTP family member PTEN, which terminates signals generated by phosphatidylinositol-3-kinase. These studies provide causal evidence for the enhancement of insulin signaling by ROS in vivo.

Loh, Kim; Deng, Haiyang; Fukushima, Atsushi; Cai, Xiaochu; Boivin, Benoit; Galic, Sandra; Bruce, Clinton; Shields, Benjamin J.; Skiba, Beata; Ooms, Lisa M.; Stepto, Nigel; Wu, Ben; Mitchell, Christina A.; Tonks, Nicholas K.; Watt, Matthew J.; Febbraio, Mark A.; Crack, Peter J.; Andrikopoulos, Sofianos; Tiganis, Tony

2010-01-01

34

Reactive oxygen species enhance insulin sensitivity.  

PubMed

Chronic reactive oxygen species (ROS) production by mitochondria may contribute to the development of insulin resistance, a primary feature of type 2 diabetes. In recent years it has become apparent that ROS generation in response to physiological stimuli such as insulin may also facilitate signaling by reversibly oxidizing and inhibiting protein tyrosine phosphatases (PTPs). Here we report that mice lacking one of the key enzymes involved in the elimination of physiological ROS, glutathione peroxidase 1 (Gpx1), were protected from high-fat-diet-induced insulin resistance. The increased insulin sensitivity in Gpx1(-/-) mice was attributed to insulin-induced phosphatidylinositol-3-kinase/Akt signaling and glucose uptake in muscle and could be reversed by the antioxidant N-acetylcysteine. Increased insulin signaling correlated with enhanced oxidation of the PTP family member PTEN, which terminates signals generated by phosphatidylinositol-3-kinase. These studies provide causal evidence for the enhancement of insulin signaling by ROS in vivo. PMID:19808019

Loh, Kim; Deng, Haiyang; Fukushima, Atsushi; Cai, Xiaochu; Boivin, Benoit; Galic, Sandra; Bruce, Clinton; Shields, Benjamin J; Skiba, Beata; Ooms, Lisa M; Stepto, Nigel; Wu, Ben; Mitchell, Christina A; Tonks, Nicholas K; Watt, Matthew J; Febbraio, Mark A; Crack, Peter J; Andrikopoulos, Sofianos; Tiganis, Tony

2009-10-01

35

Reactive oxygen species and the cardiovascular system.  

PubMed

Ever since the discovery of free radicals, many hypotheses on the deleterious actions of reactive oxygen species (ROS) have been proposed. However, increasing evidence advocates the necessity of ROS for cellular homeostasis. ROS are generated as inherent by-products of aerobic metabolism and are tightly controlled by antioxidants. Conversely, when produced in excess or when antioxidants are depleted, ROS can inflict damage to lipids, proteins, and DNA. Such a state of oxidative stress is associated with many pathological conditions and closely correlated to oxygen consumption. Although the deleterious effects of ROS can potentially be reduced by restoring the imbalance between production and clearance of ROS through administration of antioxidants (AOs), the dosage and type of AOs should be tailored to the location and nature of oxidative stress. This paper describes several pathways of ROS signaling in cellular homeostasis. Further, we review the function of ROS in cardiovascular pathology and the effects of AOs on cardiovascular outcomes with emphasis on the so-called oxidative paradox. PMID:23738043

Taverne, Yannick J H J; Bogers, Ad J J C; Duncker, Dirk J; Merkus, Daphne

2013-04-22

36

Oxidation of DNA and its components with reactive oxygen species  

NASA Astrophysics Data System (ADS)

The mechanisms of oxidation of nucleosides, nucleotides and DNA with reactive oxygen species including singlet oxygen, superoxide and hydroxyl radicals and high-valence metal oxo complexes are considered.

Kuznetsova, A. A.; Knorre, Dmitrii G.; Fedorova, Olga S.

2009-07-01

37

Production and Consumption of Reactive Oxygen Species by Fullerenes  

EPA Science Inventory

Reactive oxygen species (ROS) are one of the most important intermediates in chemical, photochemical, and biological processes. To understand the environmental exposure and toxicity of fullerenes better, the production and consumption of ROS (singlet oxygen, superoxide, hydrogen ...

38

Reactive Oxygen and Reactive Nitrogen Species in the Lung  

Microsoft Academic Search

\\u000a Reactive oxygen species (ROS) and reactive nitrogen species (RNS) have been implicated as contributing to the pathogenesis\\u000a of a broad spectrum of diseases [1, 2]. Historically, oxygen free radicals were primarily considered to be aggressive species, indeed the superoxide (O2.- theory of oxygen toxicity is based on this hypothesis, (reviewed in 3). There is circumstantial evidence to support this\\u000a view,

Gregory J. Quinlan; Nicholas J. Lamb

39

Reactive Oxygen Species in Cancer Stem Cells  

PubMed Central

Abstract Significance: Reactive oxygen species (ROS), byproducts of aerobic metabolism, are increased in many types of cancer cells. Increased endogenous ROS lead to adaptive changes and may play pivotal roles in tumorigenesis, metastasis, and resistance to radiation and chemotherapy. In contrast, the ROS generated by xenobiotics disturb the redox balance and may selectively kill cancer cells but spare normal cells. Recent Advances: Cancer stem cells (CSCs) are integral parts of pathophysiological mechanisms of tumor progression, metastasis, and chemo/radio resistance. Currently, intracellular ROS in CSCs is an active field of research. Critical Issues: Normal stem cells such as hematopoietic stem cells reside in niches characterized by hypoxia and low ROS, both of which are critical for maintaining the potential for self-renewal and stemness. However, the roles of ROS in CSCs remain poorly understood. Future Directions: Based on the regulation of ROS levels in normal stem cells and CSCs, future research may evaluate the potential therapeutic application of ROS elevation by exogenous xenobiotics to eliminate CSCs. Antioxid. Redox Signal. 16, 1215–1228.

Shi, Xiaoke; Zhang, Yan; Zheng, Junheng

2012-01-01

40

Reactive Oxygen Species, SUMOylation, and Endothelial Inflammation  

PubMed Central

Although the exact mechanism through which NADPH oxidases (Nox's) generate reactive oxygen species (ROS) is still not completely understood, it is widely considered that ROS accumulation is the cause of oxidative stress in endothelial cells. Increasing pieces of evidence strongly indicate the role for ROS in endothelial inflammation and dysfunction and subsequent development of atherosclerotic plaques, which are causes of various pathological cardiac events. An overview for a causative relationship between ROS and endothelial inflammation will be provided in this review. Particularly, a crucial role for specific protein SUMOylation in endothelial inflammation will be presented. Given that SUMOylation of specific proteins leads to increased endothelial inflammation, targeting specific SUMOylated proteins may be an elegant, effective strategy to control inflammation. In addition, the involvement of ROS production in increasing the risk of recurrent coronary events in a sub-group of non-diabetic, post-infarction patients with elevated levels of HDL-cholesterol will be presented with the emphasis that elevated HDL-cholesterol under certain inflammatory conditions can lead to increased incidence of cardiovascular events.

Le, Nhat-Tu; Corsetti, James P.; Dehoff-Sparks, Janet L.; Sparks, Charles E.; Fujiwara, Keigi; Abe, Jun-ichi

2012-01-01

41

Reactive Oxygen Species Controls Endometriosis Progression  

PubMed Central

Endometriosis is associated with chronic inflammation, and reactive oxygen species (ROS) are proinflammatory mediators that modulate cell proliferation. We have investigated whether the dysregulation of ROS production in endometriotic cells correlates with a pro-proliferative phenotype and can explain the spreading of this disease. Stromal and epithelial cells were purified from ovarian endometrioma and eutopic endometrium from 14 patients with endometriosis to produce four primary cell lines from each patient. ROS production, detoxification pathways, cell proliferation, and mitogen-activated protein kinase pathway activation were studied and compared with epithelial and stromal cell lines from 14 patients without endometriosis. Modulation of the proliferation of endometriosis by N-acetyl-cysteine, danazol, and mifepristone was tested in vitro and in 28 nude mice implanted with endometriotic tissue of human origin. Endometriotic cells displayed higher endogenous oxidative stress with an increase in ROS production, alterations in ROS detoxification pathways, and a drop in catalase levels, as observed for tumor cells. This increase in endogenous ROS correlated with increased cellular proliferation and activation of ERK1/2. These phenomena were abrogated by the antioxidant molecule N-acetyl-cysteine both in vitro and in a mouse model of endometriosis. Human endometriotic cells display activated pERK, enhanced ROS production, and proliferative capability. Our murine model shows that antioxidant molecules could be used as safe and efficient treatments for endometriosis.

Ngo, Charlotte; Chereau, Christiane; Nicco, Carole; Weill, Bernard; Chapron, Charles; Batteux, Frederic

2009-01-01

42

Activated oxygen species and oxidation of food constituents.  

PubMed

Activated oxygen species which may be important in initiating oxidative changes in foods include singlet oxygen, hydroxyl radical, ozone, superoxide anion (perhydroxyl radical at low pH), and hydrogen peroxide. Chemical and enzymic reactions known to occur in biological materials can generate singlet oxygen, hydroxyl radical, superoxide anion, and hydrogen peroxide. Ozone is primarily a product of photoreactions in polluted air. Reactions involving singlet oxygen, hydroxyl radical, and ozone with food constituents can ultimately yield peroxides which decompose to initiate oxidative chain reactions. Superoxide anion and hydrogen peroxide are relatively inert toward organic molecules but can decompose to produce the more reactive singlet oxygen and hydroxyl radical. Inhibition of reactions initiated by reactive oxygen species in foods should be very important in preserving the oxidative stability of foods. The generation, detection, measurement, reaction, and inhibition of reactions of active oxygen species are surveyed in this review. PMID:215383

Korycka-Dahl, M B; Richardson, T

1978-01-01

43

How mitochondria produce reactive oxygen species  

PubMed Central

The production of ROS (reactive oxygen species) by mammalian mitochondria is important because it underlies oxidative damage in many pathologies and contributes to retrograde redox signalling from the organelle to the cytosol and nucleus. Superoxide (O2•?) is the proximal mitochondrial ROS, and in the present review I outline the principles that govern O2•? production within the matrix of mammalian mitochondria. The flux of O2•? is related to the concentration of potential electron donors, the local concentration of O2 and the second-order rate constants for the reactions between them. Two modes of operation by isolated mitochondria result in significant O2•? production, predominantly from complex I: (i) when the mitochondria are not making ATP and consequently have a high ?p (protonmotive force) and a reduced CoQ (coenzyme Q) pool; and (ii) when there is a high NADH/NAD+ ratio in the mitochondrial matrix. For mitochondria that are actively making ATP, and consequently have a lower ?p and NADH/NAD+ ratio, the extent of O2•? production is far lower. The generation of O2•? within the mitochondrial matrix depends critically on ?p, the NADH/NAD+ and CoQH2/CoQ ratios and the local O2 concentration, which are all highly variable and difficult to measure in vivo. Consequently, it is not possible to estimate O2•? generation by mitochondria in vivo from O2•?-production rates by isolated mitochondria, and such extrapolations in the literature are misleading. Even so, the description outlined here facilitates the understanding of factors that favour mitochondrial ROS production. There is a clear need to develop better methods to measure mitochondrial O2•? and H2O2 formation in vivo, as uncertainty about these values hampers studies on the role of mitochondrial ROS in pathological oxidative damage and redox signalling.

Murphy, Michael P.

2008-01-01

44

Reactive oxygen species in pulmonary vascular remodeling.  

PubMed

The pathogenesis of pulmonary hypertension is a complex multifactorial process that involves the remodeling of pulmonary arteries. This remodeling process encompasses concentric medial thickening of small arterioles, neomuscularization of previously nonmuscular capillary-like vessels, and structural wall changes in larger pulmonary arteries. The pulmonary arterial muscularization is characterized by vascular smooth muscle cell hyperplasia and hypertrophy. In addition, in uncontrolled pulmonary hypertension, the clonal expansion of apoptosis-resistant endothelial cells leads to the formation of plexiform lesions. Based upon a large number of studies in animal models, the three major stimuli that drive the vascular remodeling process are inflammation, shear stress, and hypoxia. Although, the precise mechanisms by which these stimuli impair pulmonary vascular function and structure are unknown, reactive oxygen species (ROS)-mediated oxidative damage appears to play an important role. ROS are highly reactive due to their unpaired valence shell electron. Oxidative damage occurs when the production of ROS exceeds the quenching capacity of the antioxidant mechanisms of the cell. ROS can be produced from complexes in the cell membrane (nicotinamide adenine dinucleotide phosphate-oxidase), cellular organelles (peroxisomes and mitochondria), and in the cytoplasm (xanthine oxidase). Furthermore, low levels of tetrahydrobiopterin (BH4) and L-arginine the rate limiting cofactor and substrate for endothelial nitric oxide synthase (eNOS), can cause the uncoupling of eNOS, resulting in decreased NO production and increased ROS production. This review will focus on the ROS generation systems, scavenger antioxidants, and oxidative stress associated alterations in vascular remodeling in pulmonary hypertension. PMID:23897679

Aggarwal, Saurabh; Gross, Christine M; Sharma, Shruti; Fineman, Jeffrey R; Black, Stephen M

2013-07-01

45

How mitochondria produce reactive oxygen species.  

PubMed

The production of ROS (reactive oxygen species) by mammalian mitochondria is important because it underlies oxidative damage in many pathologies and contributes to retrograde redox signalling from the organelle to the cytosol and nucleus. Superoxide (O2(*-)) is the proximal mitochondrial ROS, and in the present review I outline the principles that govern O2(*-) production within the matrix of mammalian mitochondria. The flux of O2(*-) is related to the concentration of potential electron donors, the local concentration of O2 and the second-order rate constants for the reactions between them. Two modes of operation by isolated mitochondria result in significant O2(*-) production, predominantly from complex I: (i) when the mitochondria are not making ATP and consequently have a high Deltap (protonmotive force) and a reduced CoQ (coenzyme Q) pool; and (ii) when there is a high NADH/NAD+ ratio in the mitochondrial matrix. For mitochondria that are actively making ATP, and consequently have a lower Deltap and NADH/NAD+ ratio, the extent of O2(*-) production is far lower. The generation of O2(*-) within the mitochondrial matrix depends critically on Deltap, the NADH/NAD+ and CoQH2/CoQ ratios and the local O2 concentration, which are all highly variable and difficult to measure in vivo. Consequently, it is not possible to estimate O2(*-) generation by mitochondria in vivo from O2(*-)-production rates by isolated mitochondria, and such extrapolations in the literature are misleading. Even so, the description outlined here facilitates the understanding of factors that favour mitochondrial ROS production. There is a clear need to develop better methods to measure mitochondrial O2(*-) and H2O2 formation in vivo, as uncertainty about these values hampers studies on the role of mitochondrial ROS in pathological oxidative damage and redox signalling. PMID:19061483

Murphy, Michael P

2009-01-01

46

Energetic Species in Condensed Oxygen/Ozone.  

National Technical Information Service (NTIS)

The main objective of this work is to investigate cryogenic solids containing ozone (O3), oxygen molecules (O2) and oxygen atoms (O) to evaluate their potential as components of an advanced propulsion system. SRI examined reactive processes in involved in...

R. A. Copeland

2000-01-01

47

Reactive oxygen species and exercise on bone metabolism: friend or enemy?  

PubMed

Reactive oxygen species (ROS) are well recognised for playing a dual role as both deleterious and beneficial species. They are normally generated by tightly regulated enzymes. ROS overproduction arises either from mitochondrial electron transport chain or excessive stimulation of NAD(P)H resulting in oxidative stress, a deleterious process that can be an important mediator of damage to cell structures (lipids, membranes, proteins, and DNA). However, ROS could have a beneficial affect at low/moderate concentrations. Physiological roles in cellular responses to noxia have been reported, in defence against infectious agents, in the function of a number of cellular signalling pathways, and the induction of a mitogenic response. The role of ROS in bone metabolism is dual. It is a key modulator of bone cell function and also implicated in the pathophysiology of mineral tissues. Elevated production of ROS and/or depletion of antioxidants have also been observed in a variety of pathological conditions, including inflammatory joint diseases. Performing physical exercise is associated with numerous health benefits, playing a role especially in the prevention of bone loss. However, the production of ROS increases during demanding exercise. To explore this further, the aim of the present review was to examine bone remodelling in relation to oxidative stress and exercise. PMID:22578961

Filaire, Edith; Toumi, Hechmi

2012-05-09

48

Energetic Species in Condensed Oxygen/Ozone.  

National Technical Information Service (NTIS)

The goal of the High Energy Density Matter Program of the Air Force, the development of a rocket propellant that significantly improves on the performance of the conventional liquid hydrogen/liquid oxygen rocket propellant, is an ambitious and important u...

R. A. Copeland H. Helm M. Dyer

1997-01-01

49

Production of Reactive Oxygen Species by Polyhalogenated Cyclic Hydrocarbons (PCH).  

National Technical Information Service (NTIS)

The results of this research strongly support the hypothesis that polyhalogenated cyclic hydrocarbons (PCH) induce production of reactive oxygen species which may contribute to many of the toxic manifestations associated with these xenobiotics. A non-inva...

S. J. Stohs

1992-01-01

50

Chemistry and Reactions of Reactive Oxygen Species in Foods  

Microsoft Academic Search

Reactive oxygen species (ROS) are formed enzymatically, chemically, photochemically, and by irradiation of food. They are also formed by the decomposition and the inter-reactions of ROS. Hydroxy radical is the most reactive ROS, followed by singlet oxygen. Reactions of ROS with food components produce undesirable volatile compounds and carcinogens, destroy essential nutrients, and change the functionalities of proteins, lipids, and

Eunok Choe; David B. Min

2006-01-01

51

Reactive oxygen species and DNA damage after ultrasound exposure  

Microsoft Academic Search

The aim of this work was to detect the formation of hydrogen peroxide and hydroxyl radicals after ultrasound (US) exposure and test the hypothesis that reactive oxygen species induced by ultrasound can contribute to DNA damage. Formation of reactive oxygen species was observed in incubated medium after sonication with 1MHz continuous ultrasound at the intensities of 0.61–2.44W\\/cm2. Free radicals and

Katarzyna Milowska; Teresa Gabryelak

2007-01-01

52

Reactive Oxygen Species and Neuronal Function  

Microsoft Academic Search

ROS including •NO have profound effects on neuronal function. We have come a long way in our understanding of Paul Bert’s\\u000a observation that high pressures of oxygen cause seizures. Sites sensitive to redox regulation are clearly a factor in both\\u000a presynaptic transmitter release and the postsynaptic response to neurotransmitters. Transmitter release is decreased by •O?2, H2O2 and •OH as well

Carol A. Colton; Daniel L. Gilbert

53

ARSENIC SPECIES CAUSE RELEASE OF IRON FROM FERRITIN GENERATING REACTIVIE OXYGEN SPECIES  

EPA Science Inventory

ARSENIC SPECIES. CAUSE RELEASE OF IRON , FROM FERRITIN GENERATING REACTIVE OXYGEN SPECIES Arsenic-associated cancer (lung, bladder, skin, liver, kidney) remains a significant world- wide public health problem (e.g., Taiwan, Chile, Bangladesh, India, China and Thailand). R...

54

ARSENIC SPECIES CAUSE RELEASE OF IRON FROM FERRITIN GENERATING REACTIVE OXYGEN SPECIES  

EPA Science Inventory

ARSENIC SPECIES CAUSE RELEASE OF IRON FROM FERRITIN GENERATING REACTIVE OXYGEN SPECIES Arsenic-associated cancer (lung, bladder, skin, liver, kidney) remains a significant world- wide public health problem (e.g., Taiwan, Chile, Bangladesh, India, China and Thailand). Rece...

55

Reactive oxygen species in vascular biology: implications in hypertension  

Microsoft Academic Search

Reactive oxygen species (ROS), including superoxide (·O 2 ?), hydrogen peroxide (H 2O 2), and hydroxyl anion (OH-), and reactive nitrogen species, such as nitric oxide (NO) and peroxynitrite (ONOO ?), are biologically important O 2 derivatives that are increasingly recognized to be important in vascular biology through their oxidation\\/reduction (redox) potential. All vascular cell types (endothelial cells, vascular smooth

R. M. Touyz; E. L. Schiffrin

2004-01-01

56

Reactive oxygen species cause diabetes-induced decrease in renal oxygen tension  

Microsoft Academic Search

Aims\\/hypothesis  Augmented formation of reactive oxygen species (ROS) induced by hyperglycaemia has been suggested to contribute to the development of diabetic nephropathy. This study was designed to evaluate the influence of streptozotocin (STZ)-induced diabetes mellitus, as well as the effects of preventing excessive ROS formation by -tocopherol treatment, on regional renal blood flow, oxygen tension and oxygen consumption in anaesthetized Wistar

F. Palm; J. Cederberg; P. Hansell; P. Liss; P.-O. Carlsson

2003-01-01

57

Reactive oxygen species in melanoma and its therapeutic implications  

Microsoft Academic Search

Oxidative phosphorylation in the mitochondria is an important energy-producing process for eukaryotic cells, but this process can also result in producing potentially cell-damaging side products. Oxygen is the final proton acceptor in this cascade of electron\\/proton transfer and results in harmless water. The electron transfer, however, is not completely efficient and results in the production of reactive oxygen species (ROS).

Hanneke G. M. Wittgen; Léon C. L. T. van Kempen

2007-01-01

58

REACTIVE OXYGEN SPECIES: Metabolism, Oxidative Stress, and Signal Transduction  

Microsoft Academic Search

? Abstract Several reactive oxygen,species (ROS) are continuously,produced,in plants as byproducts,of aerobic metabolism. Depending,on the nature of the ROS species, some are highly toxic and rapidly detoxified by various cellular enzymatic and,nonenzymatic,mechanisms.,Whereas,plants are surfeited with mechanisms,to combat increased ROS levels during abiotic stress conditions, in other circumstances plants appear to purposefully,generate ROS as signaling molecules,to control various processes including pathogen

Klaus Apel; Heribert Hirt

2004-01-01

59

The oxygen isotope equilibrium fractionation between sulfite species and water  

NASA Astrophysics Data System (ADS)

Sulfite is an important sulfoxy intermediate in oxidative and reductive sulfur cycling in the marine and terrestrial environment. Different aqueous sulfite species exist, such as dissolved sulfur dioxide (SO2), bisulfite (HSO3-), pyrosulfite (S2O52-) and sulfite sensu stricto (SO32-), whereas their relative abundance in solution depends on the concentration and the pH. Conversion of one species into another is rapid and involves in many cases incorporation of oxygen from, or release of oxygen to, water (e.g. SO2 + H2O ? HSO3- + H+), resulting in rapid oxygen isotope exchange between sulfite species and water. Consequently, the oxygen isotope composition of sulfite is strongly influenced by the oxygen isotope composition of water. Since sulfate does not exchange oxygen isotopes with water under most earth surface conditions, it can preserve the sulfite oxygen isotope signature that it inherits via oxidative and reductive sulfur cycling. Therefore, interpretation of ?18O values strongly hinges on the oxygen isotope equilibrium fractionation between sulfite and water which is poorly constrained. This is in large part due to technical difficulties in extraction of sulfite from solution for oxygen isotope analysis. To overcome these challenges, anoxic isotope equilibration experiments were performed with dissolved sodium sulfite in solutions with distinct oxygen isotope signatures. Sulfite was precipitated using two different agents, barium chloride and silver nitrate. The experiments were performed at 22 °C and varying pH of 1.5, 6.3, 6.6, and 9.7 to investigate how changes in sulfite speciation affect the oxygen isotope equilibrium fractionation between sulfite and water. From the experiments at pH 1.5 where SO2 is the dominant sulfite species, a rough estimate of 37.0‰ was determined for the oxygen isotope equilibrium fractionation factor between aqueous SO2 and water (?SO?HOEQ). The oxygen isotope equilibrium fractionation between the aqueous phases is much larger than the known oxygen isotope equilibrium fractionation between gaseous SO2 and water vapor, probably because of a stronger association with water molecules. At pH values of 6.3-9.7 a more firm estimate for the oxygen isotope equilibrium fractionation between HSO3-, SO32- and water (?SO32-?HOEQ) of 15.2 ± 0.7‰ was obtained. Our results provide new insights into the oxygen isotope fractionation during reductive and oxidative sulfur cycling. They demonstrate that isotope exchange between sulfite and water during dissimilatory sulfate reduction (DSR) alone is too small to be responsible for the apparent oxygen isotope equilibrium fractionation between sulfate and water mediated by DSR. Our estimates also provide a basis for tracing and quantifying the transformation of sulfoxy intermediates during the oxidation of reduced sulfur compounds to sulfate.

Müller, Inigo A.; Brunner, Benjamin; Breuer, Christian; Coleman, Max; Bach, Wolfgang

2013-11-01

60

Role of reactive oxygen species in low level light therapy  

NASA Astrophysics Data System (ADS)

This review will focus on the role of reactive oxygen species in the cellular and tissue effects of low level light therapy (LLLT). Coincidentally with the increase in electron transport and in ATP, there has also been observed by intracellular fluorescent probes and electron spin resonance an increase in intracellular reactive oxygen species (ROS) such as superoxide, hydrogen peroxide, singlet oxygen and hydroxyl radical. ROS scavengers, antioxidants and ROS quenchers block many LLLT processes. It has been proposed that light between 400-500- nm may produce ROS by a photosensitization process involving flavins, while longer wavelengths may directly produce ROS from the mitochondria. Several redox-sensitive transcription factors are known such as NF-kB and AP1, that are able to initiate transcription of genes involved in protective responses to oxidative stress. It may be the case that LLLT can be pro-oxidant in the short-term, but anti-oxidant in the long-term.

Chen, Aaron Chi-Hao; Huang, Ying-Ying; Arany, Praveen R.; Hamblin, Michael R.

2009-02-01

61

[Influence of reactive nitrogen and oxygen species on human organism].  

PubMed

Reactive nitrogen species (RNS) and oxygen (ROS) species play a very positive and important role in the process of cells communication. The maintenance of certain level of radicals in cells is necessary for the information flow between cells and inside cells. The liquidation of free radicals presence or an increase in their level may to some extent disturb the cellular communication. Even slight fluctuations in the basic level of ROS significantly affect the change in the cell's metabolism, expression of genes and posttranslational modification of proteins. When the level of free oxygen radicals exceeds the antioxidative possibilities of the cell, an oxidative stress occurs, which causes many diseases and accelerated aging of the organism. Aging is natural, complex process, but apart from the programmed aging the reactive oxygen molecules, which are external agressors, accelerate this process. PMID:20120716

Puzanowska-Tarasiewicz, Helena; Ku?micka, Ludmi?a; Tarasiewicz, Miros?aw

2009-12-01

62

Reactive oxygen species and vascular biology: implications in human hypertension  

Microsoft Academic Search

Increased vascular production of reactive oxygen species (ROS; termed oxidative stress) has been implicated in various chronic diseases, including hypertension. Oxidative stress is both a cause and a consequence of hypertension. Although oxidative injury may not be the sole etiology, it amplifies blood pressure elevation in the presence of other pro-hypertensive factors. Oxidative stress is a multisystem phenomenon in hypertension

Rhian M Touyz; Ana M Briones

2011-01-01

63

The role of active oxygen species in plant signal transduction  

Microsoft Academic Search

Adequate responses to environmental changes are crucial for plant growth and survival. However, the molecular and biochemical mechanisms that orchestrate these responses are still poorly understood and the signaling networks involved remain elusive. A central role for active oxygen species (AOS) during biotic and abiotic stress responses is well-recognized, although under these situations AOS can either exacerbate damage or act

Frank Van Breusegem; Eva Vranová; James F. Dat; Dirk Inzé

2001-01-01

64

Reactive oxygen species and the brain in sleep apnea  

Microsoft Academic Search

Rodents exposed to intermittent hypoxia (IH), a model of obstructive sleep apnea (OSA), manifest impaired learning and memory and somnolence. Increased levels of reactive oxygen species (ROS), oxidative tissue damage, and apoptotic neuronal cell death are associated with the presence of IH-induced CNS dysfunction. Furthermore, treatment with antioxidants or overexpression of antioxidant enzymes is neuroprotective during IH. These findings mimic

Yang Wang; Shelley X. L. Zhang; David Gozal

2010-01-01

65

Antioxidants and reactive oxygen species in human fertility  

Microsoft Academic Search

The cellular components of the human reproductive system are as vulnerable as other cells to the potential detrimental effects of reactive oxygen species (ROS). Antioxidant protection is thus required, though not yet fully characterized, at sites of gametogenesis, fertilization and implantation. Spermatozoa are highly susceptible to oxidative damage due to the high content of polyunsaturated fatty acids within their plasma

Clare T. Taylor

2001-01-01

66

Reactive oxygen species and superoxide dismutases: Role in joint diseases  

Microsoft Academic Search

Reactive oxygen species (ROS) are produced in many normal and abnormal processes in humans, including atheroma, asthma, joint diseases, aging, and cancer. The superoxide anion O2? is the main ROS. Increased ROS production leads to tissue damage associated with inflammation. Superoxide dismutases (SODs) convert superoxide to hydrogen peroxide, which is then removed by glutathione peroxidase or catalase. Thus, SODs prevent

Valéry Afonso; Romuald Champy; Dragoslav Mitrovic; Pascal Collin; Abderrahim Lomri

2007-01-01

67

Infections in the male genital tract and reactive oxygen species  

Microsoft Academic Search

In the male genital tract, reactive oxygen species (ROS) are generated by spermatozoa and leukocytes including neutrophils and macrophages. ROS are involved in the regulation of sperm functions such as capacitation and the acrosome reaction. Infections lead to an excessive ROS production, resulting in an 'oxidative burst' from neutrophils\\/macrophages as a first-line defence mechanism. This is modulated by several cytokines

F. R. Ochsendorf

1999-01-01

68

Free Reactive Oxygen Species and Nephrotoxicity of Contrast Agents  

Microsoft Academic Search

Background: The nephrotoxicity induced by contrast media remains a serious clinical problem, and the underlying mechanism has not been completely understood. Experimental and clinical investigations suggest that reactive oxygen species (ROS) are critical determinants of radiocontrast nephropathy (RCN), and that antioxidants can prevent this damage. Methods: Cultured human proximal renal tubule cells (HK-2) were exposed to hydrogen peroxide (H2O2) at

Ulla Haeussler; Martin Riedel; Frieder Keller

2004-01-01

69

Singlet Oxygen Is the Major Reactive Oxygen Species Involved in Photooxidative Damage to Plants  

Microsoft Academic Search

Reactive oxygen species act as signaling molecules but can also directly provoke cellular damage by rapidly oxidizing cellular components, including lipids. We developed a high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry-based quantitative method that allowed us to discriminate between free radical (type I)- and singlet oxygen ( $^{1}{\\\\rm{O}}_{2}$; type II)-mediated lipid peroxidation (LPO) signatures by using hydroxy fatty acids as specific

Christian Triantaphylidès; Markus Krischke; Frank Alfons Hoeberichts; Brigitte Ksas; Gabriele Gresser; Michel Havaux; Frank Van Breusegem; Martin Johannes Mueller

2008-01-01

70

Multiple antioxidant proteins protect Chlorobaculum tepidum against oxygen and reactive oxygen species  

Microsoft Academic Search

The genome of the green sulfur bacterium Chlorobaculum (Cba.) tepidum, a strictly anaerobic photolithoautotroph, is predicted to encode more than ten genes whose products are potentially involved\\u000a in protection from reactive oxygen species and an oxidative stress response. The encoded proteins include cytochrome bd quinol oxidase, NADH oxidase, rubredoxin oxygen oxidoreductase, several thiol peroxidases, alkyl hydroperoxide reductase,\\u000a superoxide dismutase, methionine

Hui Li; Sara Jubelirer; Amaya M. Garcia Costas; Niels-Ulrik Frigaard; Donald A. Bryant

2009-01-01

71

Reactive Oxygen Species and Nitric Oxide in Cutaneous Leishmaniasis  

PubMed Central

Cutaneous leishmaniasis affects millions of people around the world. Several species of Leishmania infect mouse strains, and murine models closely reproduce the cutaneous lesions caused by the parasite in humans. Mouse models have enabled studies on the pathogenesis and effector mechanisms of host resistance to infection. Here, we review the role of nitric oxide (NO), reactive oxygen species (ROS), and peroxynitrite (ONOO?) in the control of parasites by macrophages, which are both the host cells and the effector cells. We also discuss the role of neutrophil-derived oxygen and nitrogen reactive species during infection with Leishmania. We emphasize the role of these cells in the outcome of leishmaniasis early after infection, before the adaptive Th-cell immune response.

Horta, Maria Fatima; Mendes, Barbara Pinheiro; Roma, Eric Henrique; Noronha, Fatima Soares Motta; Macedo, Juan Pereira; Oliveira, Luciana Souza; Duarte, Myrian Morato; Vieira, Leda Quercia

2012-01-01

72

Reactive oxygen species generation and signaling in plants  

PubMed Central

The introduction of molecular oxygen into the atmosphere was accompanied by the generation of reactive oxygen species (ROS) as side products of many biochemical reactions. ROS are permanently generated in plastids, peroxisomes, mitochiondria, the cytosol and the apoplast. Imbalance between ROS generation and safe detoxification generates oxidative stress and the accumulating ROS are harmful for the plants. On the other hand, specific ROS function as signaling molecules and activate signal transduction processes in response to various stresses. Here, we summarize the generation of ROS in the different cellular compartments and the signaling processes which are induced by ROS.

Tripathy, Baishnab Charan; Oelmuller, Ralf

2012-01-01

73

The measurement of reactive oxygen species in human neat semen and in suspended spermatozoa: a comparison  

PubMed Central

Background It is generally accepted that oxidative stress is an important factor in male infertility because it may impair the physiological function of spermatozoa at the molecular level. Nevertheless, although several approaches have been reported, the imbalance between production of reactive oxygen species (ROS) and activity of the antioxidant defense system in semen is difficult to investigate and remains poorly understood. Methods This study compares measurement of ROS production in neat semen and in washed spermatozoa obtained from the same ejaculate, and suspended in phosphate buffered saline using exactly the same luminol-mediated chemiluminescence method. Ninety one samples were obtained from males of infertile couples and 34 from volunteers with proven fertility. Results As expected, ROS levels were markedly lower in neat semen than in washed spermatozoa suspensions where seminal plasma with its potent antioxidant capacity was removed. In the cases of both neat semen and washed spermatozoa, ROS production was lowest in samples from normozoospermic males and highest in samples containing more than half million peroxidase-positive leukocytes per milliliter. For all samples, there was a significant positive correlation between ROS production by neat semen and that by washed spermatozoa suspension. Conclusion Measurement of ROS production in neat semen better reflects actual oxidative status because it detects only the overproduction of ROS which are not effectively scavenged by antioxidant capacity of seminal fluid. The results of our study show a good commutability of both measurements for identification of semen samples with high ROS production. The measurement in neat semen is even less time consuming and therefore easier to implement into laboratory routine.

Fingerova, Helena; Oborna, Ivana; Novotny, Jiri; Svobodova, Magda; Brezinova, Jana; Radova, Lenka

2009-01-01

74

Reactive Oxygen Species in Unstimulated Hemocytes of the Pacific Oyster Crassostrea gigas: A Mitochondrial Involvement  

PubMed Central

The Pacific oyster Crassostrea gigas is a sessile bivalve mollusc whose homeostasis relies, at least partially, upon cells circulating in hemolymph and referred to as hemocytes. Oyster’s hemocytes have been reported to produce reactive oxygen species (ROS), even in absence of stimulation. Although ROS production in bivalve molluscs is mostly studied for its defence involvement, ROS may also be involved in cellular and tissue homeostasis. ROS sources have not yet been described in oyster hemocytes. The objective of the present work was to characterize the ROS sources in unstimulated hemocytes. We studied the effects of chemical inhibitors on the ROS production and the mitochondrial membrane potential (??m) of hemocytes. First, this work confirmed the specificity of JC-10 probe to measure ??m in oyster hemocytes, without being affected by ?pH, as reported in mammalian cells. Second, results show that ROS production in unstimulated hemocytes does not originate from cytoplasmic NADPH-oxidase, nitric oxide synthase or myeloperoxidase, but from mitochondria. In contrast to mammalian cells, incubation of hemocytes with rotenone (complex I inhibitor) had no effect on ROS production. Incubation with antimycin A (complex III inhibitor) resulted in a dose-dependent ROS production decrease while an over-production is usually reported in vertebrates. In hemocytes of C. gigas, the production of ROS seems similarly dependent on both ??m and ?pH. These findings point out differences between mammalian models and bivalve cells, which warrant further investigation about the fine characterization of the electron transfer chain and the respective involvement of mitochondrial complexes in ROS production in hemocytes of bivalve molluscs.

Donaghy, Ludovic; Kraffe, Edouard; Le Goic, Nelly; Lambert, Christophe; Volety, Aswani K.; Soudant, Philippe

2012-01-01

75

Detection of reactive oxygen species in primary cultures of cerebellar granule cells  

Microsoft Academic Search

The aim of this work was to develop a novel procedure useful to detect the formation of two reactive oxygen species, i.e. superoxide and singlet oxygen, in neuron monolayer primary cultures, thus, making possible the investigation of the effect of certain compounds on reactive oxygen species formation. Thus, use was made of two reactive oxygen species detecting systems consisting of

A. Atlante; S. Passarella

1999-01-01

76

Chemiluminescence detection of reactive oxygen species during photodynamic therapy  

NASA Astrophysics Data System (ADS)

Photodynamic therapy (PDT) utilizes photon energy to activate a pre-administered photosensitizer drug in tissue to achieve a localized tumor control. PDT cell killing mechanism is directly related to the reactive oxygen species (ROS) produced during the photochemical reactions. Conventional PDT dosimetry evaluates distributions of the photosensitizer drug, photon propagation and absorption, and availability of molecular oxygen in the target tissue. Yet, the ultimate bullet for the damaging effect is ROS. An evaluation of ROS production during PDT should provide a more direct marker for PDT. Fluoresceinyl Cypridina Luciferin Analog (FCLA) is a chemiluminescence probe that specifically interacts with ROS (singlet oxygen and/or superoxide). The work is a preliminary investigation of the feasibility using FCLA as a means to evaluate ROS production in PDT.

Xing, Da; Qin, Yanfang; Wu, Yunxia; Zhou, Jin; Luo, Shiming; He, Yonghong; Chen, Qun

2004-06-01

77

HIV-1, Reactive Oxygen Species and Vascular Complications  

PubMed Central

Over 1 million people in the United States and 33 million individuals worldwide suffer from HIV/AIDS. Since its discovery, HIV/AIDS has been associated with an increased susceptibility to opportunistic infection due to immune dysfunction. Highly active antiretroviral therapies (HAART) restore immune function and, as a result, people infected with HIV-1 are living longer. This improved survival of HIV-1 patients has revealed a previously unrecognized risk of developing vascular complications, such as atherosclerosis and pulmonary hypertension. The mechanisms underlying these HIV-associated vascular disorders are poorly understood. However, HIV-induced elevations in reactive oxygen species, including superoxide and hydrogen peroxide, may contribute to vascular disease development and progression by altering cell function and redox-sensitive signaling pathways. In this review, we summarize the clinical and experimental evidence demonstrating HIV- and HIV antiretroviral therapy-induced alterations in reactive oxygen species (ROS) and how these effects likely contribute to vascular dysfunction and disease.

Porter, Kristi M.; Sutliff, Roy L.

2012-01-01

78

Production of Ozone and Reactive Oxygen Species After Welding  

Microsoft Academic Search

Many toxic substances including heavy metals, ozone, carbon monoxide, carbon dioxide, and nitrogen oxides are generated during\\u000a welding. Ozone (O3) is a strong oxidant that generates reactive oxygen species (ROS) in tissue, and ambient ROS exposure associated with particles\\u000a has been determined to cause DNA damage. Ozone is produced within 30 seconds during welding. However, the length of time that

H. H. Liu; Y. C. Wu; H. L. Chen

2007-01-01

79

Reactive Oxygen Species, Oxidative Stress and Plant Ion Channels  

Microsoft Academic Search

\\u000a Reactive oxygen species (ROS) are important toxic and regulatory agents in plants. They are produced in response to a number\\u000a of stimuli, including major biotic and abiotic stresses. Disruption of respiratory and photosynthetic electron transport chains,\\u000a as well as activation of NADPH oxidases (NOXs) and peroxidases, is a major reason for ROS generation and accumulation during\\u000a stress conditions. ROS production

Vadim Demidchik

80

Electrical activation induces reactive oxygen species in porcine embryos  

Microsoft Academic Search

The objectives were to determine factors affecting generation of reactive oxygen species (ROS) in porcine embryos after electrical activation of oocytes, and the effects of an antioxidant and chemical agent on ROS generation. Greater ROS were induced by electrical activation compared to IVF (mean±S.E.M., 14.6±0.8 vs. 9.2±0.4, P<0.05). Furthermore, ROS generation in embryos after electrical activation was significantly increased by

O. J. Koo; G. Jang; D. K. Kwon; J. T. Kang; O. S. Kwon; H. J. Park; S. K. Kang; B. C. Lee

2008-01-01

81

Mitochondrial  Ketoglutarate Dehydrogenase Complex Generates Reactive Oxygen Species  

Microsoft Academic Search

Mitochondria-produced reactive oxygen species (ROS) are thought to contribute to cell death caused by a multitude of pathological conditions. The molecular sites of mitochondrial ROS production are not well established but are generally thought to be located in complex I and complex III of the electron transport chain. We measured H2O2 production, respiration, and NADPH reduction level in rat brain

Anatoly A. Starkov; Gary Fiskum; Christos Chinopoulos; Beverly J. Lorenzo; Susan E. Browne; Mulchand S. Patel; M. Flint Beal

2004-01-01

82

Biochemical reactivity of melatonin with reactive oxygen and nitrogen species  

Microsoft Academic Search

Melatonin (N-acetyl-5-methoxytryptamine), an endogenously produced indole found throughout the animal kingdom, was recently reported,\\u000a using a variety of techniques, to be a scavenger of a number of reactive oxygen and reactive nitrogen species both in vitro\\u000a and in vivo. Initially, melation was discovered to directly scavenge the high toxic hydroxyl radical (•OH). The methods used\\u000a to prove the interaction of

Russel J. Reiter; Dun-xian Tan; Lucien C. Manchester; Wenbo Qi

2001-01-01

83

Preimplantation embryotoxicity after mouse embryo exposition to reactive oxygen species  

Microsoft Academic Search

Exposure of either gametes or embryos to conditions and\\/or factors that generate oxidative stress has been associated with impaired early embryogenesis. The effects of reactive oxygen species (ROS) on mouse preimplantation development, depending of the ROS-concentration and time of exposition, were studied. Two-cell embryos were incubated with 5, 10, 25 and 50 ?M of hydrogen peroxide (H2O2) for 30 and

ELISA CEBRAL; ISABEL CARRASCO; DAVID VANTMAN; ROSITA SMITH

84

Mitochondria and reactive oxygen species: physiology and pathophysiology.  

PubMed

The air that we breathe contains nearly 21% oxygen, most of which is utilized by mitochondria during respiration. While we cannot live without it, it was perceived as a bane to aerobic organisms due to the generation of reactive oxygen and nitrogen metabolites by mitochondria and other cellular compartments. However, this dogma was challenged when these species were demonstrated to modulate cellular responses through altering signaling pathways. In fact, since this discovery of a dichotomous role of reactive species in immune function and signal transduction, research in this field grew at an exponential pace and the pursuit for mechanisms involved began. Due to a significant number of review articles present on the reactive species mediated cell death, we have focused on emerging novel pathways such as autophagy, signaling and maintenance of the mitochondrial network. Despite its role in several processes, increased reactive species generation has been associated with the origin and pathogenesis of a plethora of diseases. While it is tempting to speculate that anti-oxidant therapy would protect against these disorders, growing evidence suggests that this may not be true. This further supports our belief that these reactive species play a fundamental role in maintenance of cellular and tissue homeostasis. PMID:23528859

Bolisetty, Subhashini; Jaimes, Edgar A

2013-03-19

85

Mitochondria and Reactive Oxygen Species: Physiology and Pathophysiology  

PubMed Central

The air that we breathe contains nearly 21% oxygen, most of which is utilized by mitochondria during respiration. While we cannot live without it, it was perceived as a bane to aerobic organisms due to the generation of reactive oxygen and nitrogen metabolites by mitochondria and other cellular compartments. However, this dogma was challenged when these species were demonstrated to modulate cellular responses through altering signaling pathways. In fact, since this discovery of a dichotomous role of reactive species in immune function and signal transduction, research in this field grew at an exponential pace and the pursuit for mechanisms involved began. Due to a significant number of review articles present on the reactive species mediated cell death, we have focused on emerging novel pathways such as autophagy, signaling and maintenance of the mitochondrial network. Despite its role in several processes, increased reactive species generation has been associated with the origin and pathogenesis of a plethora of diseases. While it is tempting to speculate that anti-oxidant therapy would protect against these disorders, growing evidence suggests that this may not be true. This further supports our belief that these reactive species play a fundamental role in maintenance of cellular and tissue homeostasis.

Bolisetty, Subhashini; Jaimes, Edgar A.

2013-01-01

86

A Novel Mechanism of Formaldehyde Neurotoxicity: Inhibition of Hydrogen Sulfide Generation by Promoting Overproduction of Nitric Oxide  

PubMed Central

Background Formaldehyde (FA) induces neurotoxicity by overproduction of intracellular reactive oxygen species (ROS). Increasing studies have shown that hydrogen sulfide (H2S), an endogenous gastransmitter, protects nerve cells against oxidative stress by its antioxidant effect. It has been shown that overproduction of nitric oxide (NO) inhibits the activity of cystathionine-beta-synthase (CBS), the predominant H2S-generating enzyme in the central nervous system. Objective We hypothesize that FA-caused neurotoxicity involves the deficiency of this endogenous protective antioxidant gas, which results from excessive generation of NO. The aim of this study is to evaluate whether FA disturbs H2S synthesis in PC12 cells, and whether this disturbance is associated with overproduction of NO. Principal Findings We showed that exposure of PC12 cells to FA causes reduction of viability, inhibition of CBS expression, decrease of endogenous H2S production, and NO production. CBS silencing deteriorates FA-induced decreases in endogenous H2S generation, neurotoxicity, and intracellular ROS accumulation in PC12 cells; while ADMA, a specific inhibitor of NOS significantly attenuates FA-induced decreases in endogenous H2S generation, neurotoxicity, and intracellular ROS accumulation in PC12 cells. Conclusion/Significance Our data indicate that FA induces neurotoxicity by inhibiting the generation of H2S through excess of NO and suggest that strategies to manipulate endogenous H2S could open a suitable novel therapeutic avenue for FA-induced neurotoxicity.

Zhou, Cheng-Fang; Zhuang, Yuan-Yuan; Zhang, Ping; Gu, Hong-Feng; Hu, Bi

2013-01-01

87

Reactive oxygen species produced from chromate pigments and ascorbate.  

PubMed Central

The reactions of various chromate pigments and ascorbate were investigated by an ESR spin trapping technique. Production of Cr(V) was detected directly and productions of very electrophilic reactive oxygen species (ROS) was detected via the oxidation of formate. We demonstrated previously that both dissolved oxygen and Cr (V) were essential in the production of ROS in this system, and that ROS production was inhibited by catalase. We studied here the effect of solubility of different chromate pigments: sodium, calcium, strontium, basic zinc, basic lead supported on silica, and lead and barium chromates on the production of ROS in buffered medium and cell culture medium (Dublecco's Modified Eagle medium + fetal calf serum). Sodium, calcium, basic zinc, and basic lead chromates were active in the production of ROS in presence of cell culture medium, whereas lead and barium chromates were inactive.

Lefebvre, Y; Pezerat, H

1994-01-01

88

The role of reactive oxygen species in PDT efficacy  

NASA Astrophysics Data System (ADS)

While the first reactive oxygen species (ROS) formed during photodynamic therapy (PDT) is singlet molecular oxygen (1O2), other ROS are formed downstream including superoxide anion radical (•CO2 -), hydrogen peroxide (H2O2) and hydroxyl radical (•OH). In this study, we examined the role of H2O2 in the phototoxic response to PDT in murine leukemia L388 cells. Inhibition of catalase activity, a major pathway to H2O2 detoxification, led to enhanced apoptosis and cell death. Addition of exogenous catalase offered protection from phototoxicity as did chelation of Fe+2, a co-factor in •OH production from H2O2. These results indicate the H2O2 formed during PDT plays a role in PDT efficacy.

Price, Michael; Okan-Mensah, Nakaiya; Santiago, Ann Marie; Kessel, David

2009-02-01

89

Production of intracellular reactive oxygen species and change of cell viability induced by atmospheric pressure plasma in normal and cancer cells  

NASA Astrophysics Data System (ADS)

The effects of atmospheric pressure plasma jet on cancer cells (human lung carcinoma cells) and normal cells (embryonic kidney cells and bronchial epithelial cells) were investigated. Using a detection dye, the production of intracellular reactive oxygen species (ROS) was found to be increased in plasma-treated cells compared to non-treated and gas flow-treated cells. A significant overproduction of ROS and a reduction in cell viability were induced by plasma exposure on cancer cells. Normal cells were observed to be less affected by the plasma-mediated ROS, and cell viability was less changed. The selective effect on cancer and normal cells provides a promising prospect of cold plasma as a cancer therapy.

Ja Kim, Sun; Min Joh, Hea; Chung, T. H.

2013-10-01

90

Reactive Oxygen and Nitrogen Species Regulate Mitochondrial Ca 2+ Homeostasis and Respiration  

Microsoft Academic Search

The reduction of molecular oxygen to water provides most of the biologically useful energy. However, oxygen reduction is a mixed blessing because incompletely reduced oxygen species such as superoxide or peroxides are quite reactive and can, when out of control, cause damage. In mitochondria, where most of the oxygen utilized by eukaryotic cells is reduced, the dichotomy of oxygen shows

Christoph Richter

1997-01-01

91

Oxygen limitation and thermal tolerance in two terrestrial arthropod species.  

PubMed

Recent studies of marine invertebrates and fish have suggested that lower and upper critical temperatures (CT(min) and CT(max)) are coupled by a common mechanism: oxygen and capacity limitation of thermal tolerance (OCLT). Using thermolimit respirometry, we tested the predictions of this theory for terrestrial arthropods by measuring maxima and minima for both critical temperatures and metabolic rate in two arthropods, the isopod Porcellio scaber and the beetle Tenebrio molitor, at 40%, 21%, 10% and 2.5% ambient O(2). Critical temperatures were identified as particular points on both activity and traces in four ways. In the first two instances, we identified the inflection points in regressions of absolute difference sum (ADS) residuals calculated for activity (aADS) and (VI), respectively. In the third, we visually identified the lowest point before the post-mortal peak in CO(2) release (PMV). Finally, we pinpointed the sudden drop in at death, where fell outside the 95% confidence intervals of the 5 min period immediately preceding the drop-off (CI). Minimum and maximum metabolic rates were determined using CO(2) traces, and the temperatures corresponding to these identified as T(MetMin) and T(MetMax). For both species, ambient oxygen concentration did not influence CT(min), minimum metabolic rate, or T(MetMin). By contrast, severe hypoxia (2.5% O(2)) caused a 6.9 degrees C decline in activity-based CT(max) for T. molitor and a 10.6 degrees C decline for P. scaber, relative to normoxia (21% O(2)). The magnitude of this decrease differed between methods used to estimated critical thermal limits, highlighting the need for a standard method to determine these endpoints during thermolimit respirometry. Maximum metabolic rate also declined with decreasing ambient oxygen in both species. The combination of increasing metabolic rate and oxygen limitation affected upper thermal limits in these arthropods only in severe hypoxia (2.5% O(2)). In both species, CT(min) and CT(max) responded differently to oxygen limitation, suggesting that this is not a common mechanism coupling upper and lower limits in terrestrial arthropods. PMID:20543119

Stevens, Meagan M; Jackson, Sue; Bester, Susan A; Terblanche, John S; Chown, Steven L

2010-07-01

92

Aminoferrocene-based prodrugs activated by reactive oxygen species.  

PubMed

Cancer cells generally generate higher amounts of reactive oxygen species than normal cells. On the basis of this difference, prodrugs have been developed (e.g., hydroxyferrocifen), which remain inactive in normal cells, but become activated in cancer cells. In this work we describe novel aminoferrocene-based prodrugs, which, in contrast to hydroxyferrocifen, after activation form not only quinone methides (QMs), but also catalysts (iron or ferrocenium ions). The released products act in a concerted fashion. In particular, QMs alkylate glutathione, thereby inhibiting the antioxidative system of the cell, whereas the iron species induce catalytic generation of hydroxyl radicals. Since the catalysts are formed as products of the activation reaction, it proceeds autocatalytically. The most potent prodrug described here is toxic toward cancer cells (human promyelocytic leukemia (HL-60), IC(50) = 9 ?M, and human glioblastoma-astrocytoma (U373), IC(50) = 25 ?M), but not toxic (up to 100 ?M) toward representative nonmalignant cells (fibroblasts). PMID:22185340

Hagen, Helen; Marzenell, Paul; Jentzsch, Elmar; Wenz, Frederik; Veldwijk, Marlon R; Mokhir, Andriy

2012-01-11

93

Reactive Oxygen Species Signaling Facilitates FOXO-3a/FBXO-Dependent Vascular BK Channel ?1 Subunit Degradation in Diabetic Mice  

PubMed Central

Activity of the vascular large conductance Ca2+-activated K+ (BK) channel is tightly regulated by its accessory ?1 subunit (BK-?1). Downregulation of BK-?1 expression in diabetic vessels is associated with upregulation of the forkhead box O subfamily transcription factor-3a (FOXO-3a)–dependent F-box–only protein (FBXO) expression. However, the upstream signaling regulating this process is unclear. Overproduction of reactive oxygen species (ROS) is a common finding in diabetic vasculopathy. We hypothesized that ROS signaling cascade facilitates the FOXO-3a/FBXO-mediated BK-?1 degradation and leads to diabetic BK channel dysfunction. Using cellular biology, patch clamp, and videomicroscopy techniques, we found that reduced BK-?1 expression in streptozotocin (STZ)-induced diabetic mouse arteries and in human coronary smooth muscle cells (SMCs) cultured with high glucose was attributable to an increase in protein kinase C (PKC)-? and NADPH oxidase expressions and accompanied by attenuation of Akt phosphorylation and augmentation of atrogin-1 expression. Treatment with ruboxistaurin (a PKC? inhibitor) or with GW501516 (a peroxisome proliferator–activated receptor ? activator) reduced atrogin-1 expression and restored BK channel-mediated coronary vasodilation in diabetic mice. Our results suggested that oxidative stress inhibited Akt signaling and facilitated the FOXO-3a/FBXO-dependent BK-?1 degradation in diabetic vessels. Suppression of the FOXO-3a/FBXO pathway prevented vascular BK-?1 degradation and protected coronary function in diabetes.

Lu, Tong; Chai, Qiang; Yu, Ling; d'Uscio, Livius V.; Katusic, Zvonimir S.; He, Tongrong; Lee, Hon-Chi

2012-01-01

94

Reactive oxygen species signaling facilitates FOXO-3a/FBXO-dependent vascular BK channel ?1 subunit degradation in diabetic mice.  

PubMed

Activity of the vascular large conductance Ca(2+)-activated K(+) (BK) channel is tightly regulated by its accessory ?(1) subunit (BK-?(1)). Downregulation of BK-?(1) expression in diabetic vessels is associated with upregulation of the forkhead box O subfamily transcription factor-3a (FOXO-3a)-dependent F-box-only protein (FBXO) expression. However, the upstream signaling regulating this process is unclear. Overproduction of reactive oxygen species (ROS) is a common finding in diabetic vasculopathy. We hypothesized that ROS signaling cascade facilitates the FOXO-3a/FBXO-mediated BK-?(1) degradation and leads to diabetic BK channel dysfunction. Using cellular biology, patch clamp, and videomicroscopy techniques, we found that reduced BK-?(1) expression in streptozotocin (STZ)-induced diabetic mouse arteries and in human coronary smooth muscle cells (SMCs) cultured with high glucose was attributable to an increase in protein kinase C (PKC)-? and NADPH oxidase expressions and accompanied by attenuation of Akt phosphorylation and augmentation of atrogin-1 expression. Treatment with ruboxistaurin (a PKC? inhibitor) or with GW501516 (a peroxisome proliferator-activated receptor ? activator) reduced atrogin-1 expression and restored BK channel-mediated coronary vasodilation in diabetic mice. Our results suggested that oxidative stress inhibited Akt signaling and facilitated the FOXO-3a/FBXO-dependent BK-?(1) degradation in diabetic vessels. Suppression of the FOXO-3a/FBXO pathway prevented vascular BK-?(1) degradation and protected coronary function in diabetes. PMID:22586590

Lu, Tong; Chai, Qiang; Yu, Ling; d'Uscio, Livius V; Katusic, Zvonimir S; He, Tongrong; Lee, Hon-Chi

2012-05-14

95

Tacrine-induced Reactive Oxygen Species in a Human Liver Cell Line: The Role of Anethole Dithiolethione as a Scavenger.  

PubMed

The mechanisms leading to tacrine (THA) hepatotoxic effects are not yet fully understood. Reactive oxygen species (ROS) overproduction and intracellular reduced glutathione (GSH) depletion are common mechanisms involved in drug toxicity. The aim of this study was to investigate, on the human liver cell line HepG2, whether THA at human blood concentrations induces ROS production stimulation and/or GSH depletion. A possible effect of a free radical scavenger, anethole dithiolethione (ADT), was also assessed. ROS production was measured with a fluorogen probe 2',7'-dichlorofluorescin diacetate (DCFH-DA). Reduced GSH and cell viability were measured with, respectively, monochlorobimane (mBCl) and neutral red probes. Assays were performed directly on living adherent cells in 96-well microplates, and sensitive fluorescent detection used microplate cytofluorimetry with cold light fluorimetry technology. The results showed that THA induced a concentration-dependent increase in ROS production and a decrease in GSH. Furthermore, for THA concentrations between 10 and 100 mum, ADT protected cells from ROS production stimulation and GSH depletion induced by THA. In conclusion, our in vitro study demonstrates that oxidative stress, evidenced by enhanced ROS production and GSH depletion, is a mechanism involved in THA cytotoxicity. Moreover, ADT is effective in preventing THA-induced injury. PMID:20654534

Osseni, R A; Debbasch, C; Christen, M O; Rat, P; Warnet, J M

96

Mitochondrial reactive oxygen species are required for hypothalamic glucose sensing.  

PubMed

The physiological signaling mechanisms that link glucose sensing to the electrical activity in metabolism-regulating hypothalamus are still controversial. Although ATP production was considered the main metabolic signal, recent studies show that the glucose-stimulated signaling in neurons is not totally dependent on this production. Here, we examined whether mitochondrial reactive oxygen species (mROS), which are physiologically generated depending on glucose metabolism, may act as physiological sensors to monitor the glucose-sensing response. Transient increase from 5 to 20 mmol/l glucose stimulates reactive oxygen species (ROS) generation on hypothalamic slices ex vivo, which is reversed by adding antioxidants, suggesting that hypothalamic cells generate ROS to rapidly increase glucose level. Furthermore, in vivo, data demonstrate that both the glucose-induced increased neuronal activity in arcuate nucleus and the subsequent nervous-mediated insulin release might be mimicked by the mitochondrial complex blockers antimycin and rotenone, which generate mROS. Adding antioxidants such as trolox and catalase or the uncoupler carbonyl cyanide m-chlorophenylhydrazone in order to lower mROS during glucose stimulation completely reverses both parameters. In conclusion, the results presented here clearly show that the brain glucose-sensing mechanism involved mROS signaling. We propose that this mROS production plays a key role in brain metabolic signaling. PMID:16804079

Leloup, Corinne; Magnan, Christophe; Benani, Alexandre; Bonnet, Emilie; Alquier, Thierry; Offer, Géraldine; Carriere, Audrey; Périquet, Alain; Fernandez, Yvette; Ktorza, Alain; Casteilla, Louis; Pénicaud, Luc

2006-07-01

97

AIF, reactive oxygen species, and neurodegeneration: a "complex" problem.  

PubMed

Apoptosis-inducing factor (AIF) is a flavin-binding mitochondrial intermembrane space protein that is implicated in diverse but intertwined processes that include maintenance of electron transport chain function, reactive oxygen species regulation, cell death, and neurodegeneration. In acute brain injury, AIF acquires a pro-death role upon translocation from the mitochondria to the nucleus, where it initiates chromatin condensation and large-scale DNA fragmentation. Although harlequin mice exhibiting an 80-90% global reduction in AIF protein are resistant to numerous forms of acute brain injury, they paradoxically undergo slow, progressive neurodegeneration beginning at three months of age. Brain deterioration, accompanied by markers of oxidative stress, is most pronounced in the cerebellum and retina, although it also occurs in the cortex, striatum, and thalamus. Loss of an AIF pro-survival function linked to assembly or stabilization of electron transport chain complex I underlies chronic neurodegeneration. To date, most studies of neurodegeneration have failed to adequately separate the relative importance of the mitochondrial and nuclear functions of AIF in determining the extent of injury, or whether oxidative stress plays a causative role. This review explores the complicated relationship among AIF, complex I, and the regulation of mitochondrial reactive oxygen species levels. It also discusses the controversial role of complex I deficiency in Parkinson's disease, and what can be learned from the AIF- and complex I-depleted harlequin mouse. PMID:23246553

Polster, Brian M

2012-12-12

98

Reactive oxygen species and DNA damage after ultrasound exposure.  

PubMed

The aim of this work was to detect the formation of hydrogen peroxide and hydroxyl radicals after ultrasound (US) exposure and test the hypothesis that reactive oxygen species induced by ultrasound can contribute to DNA damage. Formation of reactive oxygen species was observed in incubated medium after sonication with 1 MHz continuous ultrasound at the intensities of 0.61-2.44 W/cm2. Free radicals and hydrogen peroxide produced by ultrasound exposure of cells can lead to DNA damage. Comet assay was used to assess the effect of ultrasound on the level of nuclear DNA damage. The nucleated erythrocytes from fish were exposed in vitro to ultrasound at the same intensities and frequency. It was noticed that ultrasound in all used intensities induced DNA damage. The effect was not eliminated by the addition of catalase, which indicates that DNA damage was not caused by hydrogen peroxide only. The results showed that the DNA damage can be repair and this mechanism was the most effective after 30 and 60 min after sonication. Furthermore, the ultrasound-induced DNA damage in the presence of sonosensitizer (Zn- and AlCl-phthalocyanine) was studied. It was noticed that phthalocyaniens (Pcs) alone or with ultrasound did not induce significant changes in the level of DNA damage. PMID:17353145

Milowska, Katarzyna; Gabryelak, Teresa

2007-02-13

99

Generation of reactive oxygen species by raphidophycean phytoplankton.  

PubMed

Chattonella marina, a raphidophycean flagellate, is one of the most toxic red tide phytoplankton and causes severe damage to fish farming. Recent studies demonstrated that Chattonella sp. generates superoxide (O2-), hydrogen peroxide (H2O2), and hydroxyl radicals (.OH), which may be responsible for the toxicity of C. marina. In this study, we found the other raphidophycean flagellates such as Heterosigma akashiwo, Olisthodiscus luteus, and Fibrocapsa japonica also produce O2- and H2O2 under normal growth condition. Among the flagellate species tested, Chattonella has the highest rates of production of O2- and H2O2 as compared on the basis of cell number. This seems to be partly due to differences in their cell sizes, since Chattonella is larger than other flagellate species. The generation of O2- by these flagellate species was also confirmed by a chemiluminescence assay by using 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin++ +-3-one (MCLA). All these raphidophycean flagellates inhibited the proliferation of a marine bacterium, Vibrio alginolyticus, in a flagellates/bacteria co-culture system, and their toxic effects were suppressed by the addition of superoxide dismutase (SOD) or catalase. Our results suggest that the generation of reactive oxygen species is a common feature of raphidophycean flagellates. PMID:9362113

Oda, T; Nakamura, A; Shikayama, M; Kawano, I; Ishimatsu, A; Muramatsu, T

1997-10-01

100

Reactive oxygen species and the free radical theory of aging.  

PubMed

The traditional view in the field of free radical biology is that free radicals and reactive oxygen species (ROS) are toxic, mostly owing to direct damage of sensitive and biologically significant targets, and are thus a major cause of oxidative stress; that complex enzymatic and nonenzymatic systems act in concert to counteract this toxicity; and that a major protective role is played by the phenomenon of adaptation. Another part of the traditional view is that the process of aging is at least partly due to accumulated damage done by these harmful species. However, recent workers in this and in related fields are exploring the view that superoxide radical and reactive oxygen species exert beneficial effects. Thus, such ROS are viewed as involved in cellular regulation by acting as (redox) signals, and their harmful effects are seen mostly as a result of compromised signaling, rather than due to direct damage to sensitive targets. According to some followers of this view, ROS such as hydrogen peroxide and superoxide are not just causative agents of aging but may also be agents that increase the life span by acting, for example, as prosurvival signals. The goal of this review is to recall that many of the effects of ROS that are interpreted as beneficial may actually represent adaptations to toxicity and that some of the most extravagant recent claims may be due to misinterpretation, oversimplification, and ignoring the wealth of knowledge supporting the traditional view. Whether it is time to abandon the free radical (oxidative stress) theory of aging is considered. PMID:23434764

Liochev, Stefan I

2013-02-19

101

Metabolic interaction between astrocytes and neurons in the defense against reactive oxygen species  

Microsoft Academic Search

The cells of the adult human brain consume < 20% of the oxygen utilized by the body although the brain comprises only 2% of the body weight. Reactive oxygen species, which are produced continuously during oxidative metabolism, are generated at high rates within the brain. Therefore, the defense against the toxic effects of reactive oxygen species is an essential task

Ralf Dringen; Jan M. Gutterer; Johannes Hirrlinger

102

Matairesinol inhibits angiogenesis via suppression of mitochondrial reactive oxygen species.  

PubMed

Mitochondrial reactive oxygen species (mROS) are involved in cancer initiation and progression and function as signaling molecules in many aspects of hypoxia and growth factor-mediated signaling. Here we report that matairesinol, a natural small molecule identified from the cell-based screening of 200 natural plants, suppresses mROS generation resulting in anti-angiogenic activity. A non-toxic concentration of matairesinol inhibited the proliferation of human umbilical vein endothelial cells. The compound also suppressed in vitro angiogenesis of tube formation and chemoinvasion, as well as in vivo angiogenesis of the chorioallantoic membrane at non-toxic doses. Furthermore, matairesinol decreased hypoxia-inducible factor-1? in hypoxic HeLa cells. These results demonstrate that matairesinol could function as a novel angiogenesis inhibitor by suppressing mROS signaling. PMID:22483751

Lee, Boram; Kim, Ki Hyun; Jung, Hye Jin; Kwon, Ho Jeong

2012-03-28

103

Reactive oxygen species and vascular remodelling in hypertension: Still alive  

PubMed Central

Reactive oxygen species (ROS) are reactive derivatives of O2 metabolism, including superoxide anion, hydrogen peroxide, hydroxyl radical and nitric oxide. All types of vascular cells produce ROS, primarily via cell membrane-associated NAD(P)H oxidase. Cardiovascular diseases, such as hypertension, are associated with increased ROS formation (oxidative stress). Oxidative excess in the vasculature reduces levels of the vasodilator nitric oxide, causes tissue injury, promotes protein oxidation and DNA damage, and induces proinflammatory responses. ROS are also important intracellular signalling molecules that regulate vascular function by modulating vascular cell contraction/dilation, migration, growth/apoptosis, and extracellular matrix protein turnover, which contribute to vascular remodelling. Interventions to decrease ROS bioavailability regress remodelling and reduce blood pressure in experimental hypertension. Such strategies may have therapeutic potential in cardiovascular diseases.

Xu, Shaoping; Touyz, Rhian M

2006-01-01

104

Mitochondrial Reactive Oxygen Species Modulate Mosquito Susceptibility to Plasmodium Infection  

PubMed Central

Background Mitochondria perform multiple roles in cell biology, acting as the site of aerobic energy-transducing pathways and as an important source of reactive oxygen species (ROS) that modulate redox metabolism. Methodology/Principal Findings We demonstrate that a novel member of the mitochondrial transporter protein family, Anopheles gambiae mitochondrial carrier 1 (AgMC1), is required to maintain mitochondrial membrane potential in mosquito midgut cells and modulates epithelial responses to Plasmodium infection. AgMC1 silencing reduces mitochondrial membrane potential, resulting in increased proton-leak and uncoupling of oxidative phosphorylation. These metabolic changes reduce midgut ROS generation and increase A. gambiae susceptibility to Plasmodium infection. Conclusion We provide direct experimental evidence indicating that ROS derived from mitochondria can modulate mosquito epithelial responses to Plasmodium infection.

Oliveira, Giselle A.; Andersen, John F.; Oliveira, Marcus F.; Oliveira, Pedro L.; Barillas-Mury, Carolina

2012-01-01

105

Recent advances in reactive oxygen species measurement in biological systems.  

PubMed

Reactive oxygen species (ROS) play an essential role in facilitating signal transduction processes within the cell. However, the precise details of the redox dynamics involved are not well understood. The generation of ROS is tightly controlled both spatially and temporally within the cell, making the study of ROS dynamics particularly difficult. In order to measure these dynamics, precise tools that can specifically examine the relevant ROS are required. Recent advancements in methodologies for ROS measurement have allowed the study of ROS biology at a level of precision previously unachievable. Here, we discuss improvements to fluorescent ROS dye technologies, genetically encoded ROS reporters, nanoparticle delivery systems, and nanotube ROS probes. These technologies improve specificity, localization and sensitivity over previously available ROS probes. PMID:24120034

Woolley, J F; Stanicka, J; Cotter, T G

2013-10-09

106

Role of Reactive Oxygen Species in Antibiotic Action and Resistance  

PubMed Central

The alarming spread of bacterial strains exhibiting resistance to current antibiotic therapies necessitates that we elucidate the specific genetic and biochemical responses underlying drug-mediated cell killing, so as to increase the efficacy of available treatments and develop new antibacterials. Recent research aimed at identifying such cellular contributions has revealed that antibiotics induce changes in metabolism that promote the formation of reactive oxygen species, which play a role in cell death. Here we discuss the relationship between drug-induced oxidative stress, the SOS response and their potential combined contribution to resistance development. Additionally, we describe ways in which these responses are being taken advantage of to combat bacterial infections and arrest the rise of resistant strains.

Dwyer, Daniel J; Kohanski, Michael A; Collins, James J

2009-01-01

107

Diabetic peripheral neuropathy: role of reactive oxygen and nitrogen species.  

PubMed

The prevalence of diabetes has reached epidemic proportions. There are two forms of diabetes: type 1 diabetes mellitus is due to auto-immune-mediated destruction of pancreatic ?-cells resulting in absolute insulin deficiency and type 2 diabetes mellitus is due to reduced insulin secretion and or insulin resistance. Both forms of diabetes are characterized by chronic hyperglycemia, leading to the development of diabetic peripheral neuropathy (DPN) and microvascular pathology. DPN is characterized by enhanced or reduced thermal, chemical, and mechanical pain sensitivities. In the long-term, DPN results in peripheral nerve damage and accounts for a substantial number of non-traumatic lower-limb amputations. This review will address the mechanisms, especially the role of reactive oxygen and nitrogen species in the development and progression of DPN. PMID:23722999

Premkumar, Louis S; Pabbidi, Reddy M

2013-11-01

108

Reactive oxygen species-targeted therapeutic interventions for atrial fibrillation  

PubMed Central

Atrial fibrillation (AF) is the most common arrhythmia that requires medical attention, and its incidence is increasing. Current ion channel blockade therapies and catheter ablation have significant limitations in treatment of AF, mainly because they do not address the underlying pathophysiology of the disease. Oxidative stress has been implicated as a major underlying pathology that promotes AF; however, conventional antioxidants have not shown impressive therapeutic effects. A more careful design of antioxidant therapies and better selection of patients likely are required to treat effectively AF with antioxidant agents. Current evidence suggest inhibition of prominent cardiac sources of reactive oxygen species (ROS) such as nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and targeting subcellular compartments with the highest levels of ROS may prove to be effective therapies for AF. Increased serum markers of oxidative stress may be an important guide in selecting the AF patients who will most likely respond to antioxidant therapy.

Sovari, Ali A.; Dudley, Samuel C.

2012-01-01

109

Proteins Needed to Activate a Transcriptional Response to the Reactive Oxygen Species Singlet Oxygen  

PubMed Central

ABSTRACT Singlet oxygen (1O2) is a reactive oxygen species generated by energy transfer from one or more excited donors to molecular oxygen. Many biomolecules are prone to oxidation by 1O2, and cells have evolved systems to protect themselves from damage caused by this compound. One way that the photosynthetic bacterium Rhodobacter sphaeroides protects itself from 1O2 is by inducing a transcriptional response controlled by ChrR, an anti-? factor which releases an alternative sigma factor, ?E, in the presence of 1O2. Here we report that induction of ?E-dependent gene transcription is decreased in the presence of 1O2 when two conserved genes in the ?E regulon are deleted, including one encoding a cyclopropane fatty acid synthase homologue (RSP2144) or one encoding a protein of unknown function (RSP1091). Thus, we conclude that RSP2144 and RSP1091 are each necessary to increase ?E activity in the presence of 1O2. In addition, we found that unlike in wild-type cells, where ChrR is rapidly degraded when 1O2 is generated, turnover of this anti-? factor is slowed when cells lacking RSP2144, RSP1091, or both of these proteins are exposed to 1O2. Further, we demonstrate that the organic hydroperoxide tert-butyl hydroperoxide promotes ChrR turnover in both wild-type cells and mutants lacking RSP2144 or RSP1091, suggesting differences in the ways different types of oxidants increase ?E activity.

Nam, Tae-Wook; Ziegelhoffer, Eva C.; Lemke, Rachelle A. S.; Donohue, Timothy J.

2013-01-01

110

Reactive oxygen species mediate growth and death in submerged plants  

PubMed Central

Aquatic and semi-aquatic plants are well adapted to survive partial or complete submergence which is commonly accompanied by oxygen deprivation. The gaseous hormone ethylene controls a number of adaptive responses to submergence including adventitious root growth and aerenchyma formation. Reactive oxygen species (ROS) act as signaling intermediates in ethylene-controlled submergence adaptation and possibly also independent of ethylene. ROS levels are controlled by synthesis, enzymatic metabolism, and non-enzymatic scavenging. While the actors are by and large known, we still have to learn about altered ROS at the subcellular level and how they are brought about, and the signaling cascades that trigger a specific response. This review briefly summarizes our knowledge on the contribution of ROS to submergence adaptation and describes spectrophotometrical, histochemical, and live cell imaging detection methods that have been used to study changes in ROS abundance. Electron paramagnetic resonance (EPR) spectroscopy is introduced as a method that allows identification and quantification of specific ROS in cell compartments. The use of advanced technologies such as EPR spectroscopy will be necessary to untangle the intricate and partially interwoven signaling networks of ethylene and ROS.

Steffens, Bianka; Steffen-Heins, Anja; Sauter, Margret

2013-01-01

111

Degradative action of reactive oxygen species on hyaluronan.  

PubMed

Many human diseases are associated with harmful action of reactive oxygen species (ROS). These species are involved in the degradation of essential tissue or related components. One of such components is synovial fluid that contains a high-molecular-weight polymer--hyaluronan (HA). Uninhibited and/or inhibited hyaluronan degradation by the action of various ROS has been studied in many in vitro models. In these studies, the change of the molecular weight of HA or a related parameter, such as HA solution viscosity, has been used as a marker of inflicted damage. The aim of the presented review is to briefly summarize the available data. Their correct interpretation could contribute to the implementation of modern methods of evaluation of the antioxidative capacity of natural and synthetic substances and prospective drugs--potential inflammatory disease modifying agents. Another focus of this review is to evaluate briefly the impact of different available analytical techniques currently used to investigate the structure of native high-molecular-weight hyaluronan and/or of its fragments. PMID:16529395

Soltés, L; Mendichi, R; Kogan, G; Schiller, J; Stankovska, M; Arnhold, J

2006-03-01

112

Cellular response of pea plants to cadmium toxicity: cross talk between reactive oxygen species, nitric oxide, and calcium.  

PubMed

Cadmium (Cd) toxicity has been widely studied in different plant species; however, the mechanism involved in its toxicity as well as the cell response against the metal have not been well established. In this work, using pea (Pisum sativum) plants, we studied the effect of Cd on antioxidants, reactive oxygen species (ROS), and nitric oxide (NO) metabolism of leaves using different cellular, molecular, and biochemical approaches. The growth of pea plants with 50 mum CdCl(2) affected differentially the expression of superoxide dismutase (SOD) isozymes at both transcriptional and posttranscriptional levels, giving rise to a SOD activity reduction. The copper/zinc-SOD down-regulation was apparently due to the calcium (Ca) deficiency induced by the heavy metal. In these circumstances, the overproduction of the ROS hydrogen peroxide and superoxide could be observed in vivo by confocal laser microscopy, mainly associated with vascular tissue, epidermis, and mesophyll cells, and the production of superoxide radicals was prevented by exogenous Ca. On the other hand, the NO synthase-dependent NO production was strongly depressed by Cd, and treatment with Ca prevented this effect. Under these conditions, the pathogen-related proteins PrP4A and chitinase and the heat shock protein 71.2, were up-regulated, probably to protect cells against damages induced by Cd. The regulation of these proteins could be mediated by jasmonic acid and ethylene, whose contents increased by Cd treatment. A model is proposed for the cellular response to long-term Cd exposure consisting of cross talk between Ca, ROS, and NO. PMID:19279198

Rodríguez-Serrano, María; Romero-Puertas, María C; Pazmiño, Diana M; Testillano, Pilar S; Risueño, María C; Del Río, Luis A; Sandalio, Luisa M

2009-03-11

113

[Generation of reactive oxygen species in water under exposure of visible or infrared irradiation at absorption band of molecular oxygen].  

PubMed

It is found that in bidistilled water saturated with oxygen hydrogen peroxide and hydroxyl radicals are formed under the influence of visible and infrared radiation in the absorption bands of molecular oxygen. Formation of reactive oxygen species (ROS) occurs under the influence of both solar and artificial light sourses, including the coherent laser irradiation. The oxygen effect, i.e. the impact of dissolved oxygen concentration on production of hydrogen peroxide induced by light, is detected. It is shown that the visible and infrared radiation in the absorption bands of molecular oxygen leads to the formation of 8-oxoguanine in DNA in vitro. Physicochemical mechanisms of ROS formation in water when exposed to visible and infrared light are studied, and the involvement of singlet oxygen and superoxide anion radicals in this process is shown. PMID:22567905

Gudkov, S V; Karp, O E; Garmash, S A; Ivanov, V E; Chernikov, A V; Manokhin, A A; Astashev, M E; Iaguzhinski?, L S; Bruskov, V I

114

Effect of activated oxygen species in human lymphocytes.  

PubMed

The cytogenetic effectiveness of activated oxygen species (AOS) generated by the superoxide forming xanthine-xanthine oxidase (X/XO) system was studied in human lymphocyte cultures. The observed chromosome damage was exclusively of the chromatid type. In the experiments a clear dependence of aberration induction on XO concentration and exposure time could be demonstrated. While using anti-AOS agents, the H2O2 antagonist catalase and the hydroxyl radical scavenger formate reduced X/XO induced chromosome damage whereas superoxide dismutase (SOD) did not. In the presence of SOD, aberration frequency was even enhanced. The results indicate that the chromosome damage is caused indirectly via H2O2 formation from spontaneous dismutation of superoxide, whereas H2O2 might be reduced intracellularly giving rise to the highly reactive hydroxyl radical. This effect might be enhanced by SOD, possibly by raising the intracellular amount of easily membrane passing H2O2. Thus, referring to chromosome aberrations, SOD, which is generally reported to protect from AOS, is capable of increasing oxygen mediated biological damage. This observation might be explained by the involvement of DNA associated transition metal, like iron or copper ions, in reducing H2O2. DNA bound copper ions, thought to be necessary for maintenance of DNA quaternary structure, might represent a generator complex for the hydroxyl radical by reduction of X/XO derived hydrogen peroxide. This might cause 'site specific damage' to the DNA which is subsequently converted into chromatid-type aberration by S-dependent misreplication and/or misrepair. This is different to the formation of radiation induced chromosome aberrations which arise by an S-phase independent mechanism. PMID:7528893

Duell, T; Lengfelder, E; Fink, R; Giesen, R; Bauchinger, M

1995-01-01

115

Reactive oxygen species-inducible ECF ? factors of Bradyrhizobium japonicum.  

PubMed

Extracytoplasmic function (ECF) ? factors control the transcription of genes involved in different cellular functions, such as stress responses, metal homeostasis, virulence-related traits, and cell envelope structure. The genome of Bradyrhizobium japonicum, the nitrogen-fixing soybean endosymbiont, encodes 17 putative ECF ? factors belonging to nine different ECF ? factor families. The genes for two of them, ecfQ (bll1028) and ecfF (blr3038), are highly induced in response to the reactive oxygen species hydrogen peroxide (H(2)O(2)) and singlet oxygen ((1)O(2)). The ecfF gene is followed by the predicted anti-? factor gene osrA (blr3039). Mutants lacking EcfQ, EcfF plus OsrA, OsrA alone, or both ? factors plus OsrA were phenotypically characterized. While the symbiotic properties of all mutants were indistinguishable from the wild type, they showed increased sensitivity to singlet oxygen under free-living conditions. Possible target genes of EcfQ and EcfF were determined by microarray analyses, and candidate genes were compared with the H(2)O(2)-responsive regulon. These experiments disclosed that the two ? factors control rather small and, for the most part, distinct sets of genes, with about half of the genes representing 13% of the members of H(2)O(2)-responsive regulon. To get more insight into transcriptional regulation of both ? factors, the 5' ends of ecfQ and ecfF mRNA were determined. The presence of conserved sequence motifs in the promoter region of ecfQ and genes encoding EcfQ-like ? factors in related ?-proteobacteria suggests regulation via a yet unknown transcription factor. By contrast, we have evidence that ecfF is autoregulated by transcription from an EcfF-dependent consensus promoter, and its product is negatively regulated via protein-protein interaction with OsrA. Conserved cysteine residues 129 and 179 of OsrA are required for normal function of OsrA. Cysteine 179 is essential for release of EcfF from an EcfF-OsrA complex upon H(2)O(2) stress while cysteine 129 is possibly needed for EcfF-OsrA interaction. PMID:22916258

Masloboeva, Nadezda; Reutimann, Luzia; Stiefel, Philipp; Follador, Rainer; Leimer, Nadja; Hennecke, Hauke; Mesa, Socorro; Fischer, Hans-Martin

2012-08-16

116

Reactive Oxygen Species-Driven Transcription in Arabidopsis under Oxygen Deprivation1[W  

PubMed Central

Reactive oxygen species (ROS) play an important role as triggers of gene expression during biotic and abiotic stresses, among which is low oxygen (O2). Previous studies have shown that ROS regulation under low O2 is driven by a RHO-like GTPase that allows tight control of hydrogen peroxide (H2O2) production. H2O2 is thought to regulate the expression of heat shock proteins, in a mechanism that is common to both O2 deprivation and to heat stress. In this work, we used publicly available Arabidopsis (Arabidopsis thaliana) microarray datasets related to ROS and O2 deprivation to define transcriptome convergence pattern. Our results show that although Arabidopsis response to anoxic and hypoxic treatments share a common core of genes related to the anaerobic metabolism, they differ in terms of ROS-related gene response. We propose that H2O2 production under O2 deprivation is a trait present in a very early phase of anoxia, and that ROS are needed for the regulation of a set of genes belonging to the heat shock protein and ROS-mediated groups. This mechanism, likely not regulated via the N-end rule pathway for O2 sensing, is probably mediated by a NADPH oxidase and it is involved in plant tolerance to the stress.

Pucciariello, Chiara; Parlanti, Sandro; Banti, Valeria; Novi, Giacomo; Perata, Pierdomenico

2012-01-01

117

Sea urchin spermatozoa generate at least two reactive oxygen species; the type of reactive oxygen species changes under different conditions.  

PubMed

Reactive oxygen species (ROS) cause oxidative stress and act as signal transduction molecules in many cells. Spermatozoa from several mammals generate ROS, which are involved in male infertility and signaling during capacitation. In the present study, we investigated ROS generation by sea urchin spermatozoa at the initiation of motility, during dilution with seawater, and following egg jelly treatment. In seawater containing an ROS indicator, 5-(and 6-)chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H(2)DCFDA), fluorescence increased after the addition of spermatozoa. The ROS generation rate was dependent upon the dilution ratio and respiratory rate of the spermatozoa. Spermatozoa in sodium-free seawater did not increase fluorescence, but fluorescence did increase with the addition of NaCl. Sodium chloride also led to the initiation of sperm motility and respiration. Using the indicator MitoSOX Red, ROS generation was detected from spermatozoa exposed to egg jelly dissolved in seawater, but not in normal seawater. Moreover, the respiratory inhibitor antimycin A prevented CM-H(2)DCFDA-detectable ROS and increased MitoSox-detectable ROS at a higher concentration. These findings revealed that the ROS generated were of different species, possibly hydrogen peroxide (H(2)O(2)) and superoxide anion (O(-)(2)), and their detected levels were altered by egg jelly. We concluded that sea urchin spermatozoa generate at least two species of ROS depending on the physiological conditions to which they are exposed. It is possible that the major ROS from sea urchin spermatozoa changes during the course of fertilization. PMID:22328344

Kazama, Makoto; Hino, Akiya

2012-02-10

118

Reactive oxygen species and vascular biology: implications in human hypertension.  

PubMed

Increased vascular production of reactive oxygen species (ROS; termed oxidative stress) has been implicated in various chronic diseases, including hypertension. Oxidative stress is both a cause and a consequence of hypertension. Although oxidative injury may not be the sole etiology, it amplifies blood pressure elevation in the presence of other pro-hypertensive factors. Oxidative stress is a multisystem phenomenon in hypertension and involves the heart, kidneys, nervous system, vessels and possibly the immune system. Compelling experimental and clinical evidence indicates the importance of the vasculature in the pathophysiology of hypertension and as such much emphasis has been placed on the (patho)biology of ROS in the vascular system. A major source for cardiovascular, renal and neural ROS is a family of non-phagocytic nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (Nox), including the prototypic Nox2 homolog-based NADPH oxidase, as well as other Noxes, such as Nox1 and Nox4. Nox-derived ROS is important in regulating endothelial function and vascular tone. Oxidative stress is implicated in endothelial dysfunction, inflammation, hypertrophy, apoptosis, migration, fibrosis, angiogenesis and rarefaction, important processes involved in vascular remodeling in hypertension. Despite a plethora of data implicating oxidative stress as a causative factor in experimental hypertension, findings in human hypertension are less conclusive. This review highlights the importance of ROS in vascular biology and focuses on the potential role of oxidative stress in human hypertension. PMID:20981034

Touyz, Rhian M; Briones, Ana M

2010-10-28

119

Cyclic Stretch, Reactive Oxygen Species, and Vascular Remodeling  

PubMed Central

Abstract Blood vessels respond to changes in mechanical load from circulating blood in the form of shear stress and mechanical strain as the result of heart propulsions by changes in intracellular signaling leading to changes in vascular tone, production of vasoactive molecules, and changes in vascular permeability, gene regulation, and vascular remodeling. In addition to hemodynamic forces, microvasculature in the lung is also exposed to stretch resulting from respiratory cycles during autonomous breathing or mechanical ventilation. Among various cell signaling pathways induced by mechanical forces and reported to date, a role of reactive oxygen species (ROS) produced by vascular cells receives increasing attention. ROS play an essential role in signal transduction and physiologic regulation of vascular function. However, in the settings of chronic hypertension, inflammation, or acute injury, ROS may trigger signaling events that further exacerbate smooth muscle hypercontractility and vascular remodeling associated with hypertension and endothelial barrier dysfunction associated with acute lung injury and pulmonary edema. These conditions are also characterized by altered patterns of mechanical stimulation experienced by vasculature. This review will discuss signaling pathways regulated by ROS and mechanical stretch in the pulmonary and systemic vasculature and will summarize functional interactions between cyclic stretch- and ROS-induced signaling in mechanochemical regulation of vascular structure and function. Antioxid. Redox Signal. 11, 1651–1667.

2009-01-01

120

Electrical activation induces reactive oxygen species in porcine embryos.  

PubMed

The objectives were to determine factors affecting generation of reactive oxygen species (ROS) in porcine embryos after electrical activation of oocytes, and the effects of an antioxidant and chemical agent on ROS generation. Greater ROS were induced by electrical activation compared to IVF (mean+/-S.E.M., 14.6+/-0.8 vs. 9.2+/-0.4, P<0.05). Furthermore, ROS generation in embryos after electrical activation was significantly increased by higher intensity and longer duration electrical pulses and by higher exogenous Ca(2+) concentrations. Cleavage rate and blastocyst formation rate were not directly related to the level of ROS. Supplementation of the IVC medium with 0.5mM glutathione (GSH) reduced ROS (9.2+/-0.4 vs. 14.7+/-0.9, P<0.05). Treatment with the chemical activation agent, 6-dimethylaminopurine (6-DMAP) for 3h did not induce further ROS generation in combination with electrical activation, but it improved blastocyst formation rate (53.8+/-1.1 vs. 23.7+/-3.5, P<0.05). We concluded that generation of ROS should be considered for optimizing electrical activation and that supplementing an antioxidant or combining electrical and chemical activation induced lower ROS generation in electrically activated porcine embryos. PMID:18675447

Koo, O J; Jang, G; Kwon, D K; Kang, J T; Kwon, O S; Park, H J; Kang, S K; Lee, B C

2008-10-15

121

A mitochondrial oscillator dependent on reactive oxygen species.  

PubMed

We describe a unique mitochondrial oscillator that depends on oxidative phosphorylation, reactive oxygen species (ROS), and mitochondrial inner membrane ion channels. Cell-wide synchronized oscillations in mitochondrial membrane potential (Delta Psi(m)), NADH, and ROS production have been recently described in isolated cardiomyocytes, and we have hypothesized that the balance between superoxide anion efflux through inner membrane anion channels and the intracellular ROS scavenging capacity play a key role in the oscillatory mechanism. Here, we formally test the hypothesis using a computational model of mitochondrial energetics and Ca(2+) handling including mitochondrial ROS production, cytoplasmic ROS scavenging, and ROS activation of inner membrane anion flux. The mathematical model reproduces the period and phase of the observed oscillations in Delta Psi(m), NADH, and ROS. Moreover, we experimentally verify model predictions that the period of the oscillator can be modulated by altering the concentration of ROS scavengers or the rate of oxidative phosphorylation, and that the redox state of the glutathione pool oscillates. In addition to its role in cellular dysfunction during metabolic stress, the period of the oscillator can be shown to span a wide range, from milliseconds to hours, suggesting that it may also be a mechanism for physiological timekeeping and/or redox signaling. PMID:15345581

Cortassa, Sonia; Aon, Miguel A; Winslow, Raimond L; O'Rourke, Brian

2004-09-01

122

Stress Granules Inhibit Apoptosis by Reducing Reactive Oxygen Species Production  

PubMed Central

Cells can undergo two alternative fates following exposure to environmental stress: they either induce apoptosis or inhibit apoptosis and then repair the stress-induced alterations. These processes minimize cell loss and prevent the survival of cells with aberrant DNA and protein alterations. These two alternative fates are partly controlled by stress granules (SGs). While arsenite, hypoxia, and heat shock induce the formation of SGs that inhibit apoptosis, X-ray irradiation and genotoxic drugs do not induce SGs, and they are more prone to trigger apoptosis. However, it is unclear precisely how SGs control apoptosis. This study found that SGs suppress the elevation of reactive oxygen species (ROS), and this suppression is essential for inhibiting ROS-dependent apoptosis. This antioxidant activity of SGs is controlled by two SG components, GTPase-activating protein SH3 domain binding protein 1 (G3BP1) and ubiquitin-specific protease 10 (USP10). G3BP1 elevates the steady-state ROS level by inhibiting the antioxidant activity of USP10. However, following exposure to arsenite, G3BP1 and USP10 induce the formation of SGs, which uncovers the antioxidant activity of USP10. We also found that the antioxidant activity of USP10 requires the protein kinase activity of ataxia telangiectasia mutated (ATM). This work reveals that SGs are critical redox regulators that control cell fate under stress conditions.

Takahashi, Masahiko; Higuchi, Masaya; Matsuki, Hideaki; Yoshita, Manami; Ohsawa, Toshiaki; Oie, Masayasu

2013-01-01

123

Scavenging of reactive oxygen species by chlorophyllin: an ESR study.  

PubMed

The antioxidant effects of chlorophyllin (CHL), a water-soluble analog of the green plant pigment chlorophyll, on different reactive oxygen species (ROS) were investigated by electron spin resonance (ESR) spectroscopy. As a standard, we have used the ability of CHL to scavenge the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. CHL inhibits the formation of 5,5-dimethyl-1-pyrroline-N-oxide adduct with hydroxyl radical (DMPO-.OH adduct) generated by gamma-radiation in a dose-dependent manner. At a concentration of 1 mM, CHL caused more than 90% inhibition of ESR signal intensity of this adduct. However, the results obtained with the Fenton reaction were different. We also found evidence for the inhibition of 1O2-dependent formation of the 2,2,6,6-tetramethyl-piperidine oxide (TEMPO) radical during photosensitization of methylene blue with visible light. CHL was also able to inhibit hydrogen peroxide induced oxidation of phenol red. The rate constant of the reaction of CHL with H2O2 was found to be 2.7 x 10(6) M-1 s-1. In conclusion, CHL has potent antioxidant ability involving scavenging of various physiologically important ROS. PMID:11767414

Kumar, S S; Devasagayam, T P; Bhushan, B; Verma, N C

2001-11-01

124

Reactive oxygen species delay control of lymphocytic choriomeningitis virus.  

PubMed

Cluster of differentiation (CD)8(+) T cells are like a double edged sword during chronic viral infections because they not only promote virus elimination but also induce virus-mediated immunopathology. Elevated levels of reactive oxygen species (ROS) have been reported during virus infections. However, the role of ROS in T-cell-mediated immunopathology remains unclear. Here we used the murine lymphocytic choriomeningitis virus to explore the role of ROS during the processes of virus elimination and induction of immunopathology. We found that virus infection led to elevated levels of ROS producing granulocytes and macrophages in virus-infected liver and spleen tissues that were triggered by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Lack of the regulatory subunit p47phox of the NADPH oxidase diminished ROS production in these cells. While CD8(+) T cells exhibited ROS production that was independent of NADPH oxidase expression, survival and T-cell function was elevated in p47phox-deficient (Ncf1(-/-)) mice. In the absence of p47phox, enhanced T-cell immunity promoted virus elimination and blunted corresponding immunopathology. In conclusion, we find that NADPH-mediated production of ROS critically impairs the immune response, impacting elimination of virus and outcome of liver cell damage. PMID:23328631

Lang, P A; Xu, H C; Grusdat, M; McIlwain, D R; Pandyra, A A; Harris, I S; Shaabani, N; Honke, N; Maney, S Kumar; Lang, E; Pozdeev, V I; Recher, M; Odermatt, B; Brenner, D; Häussinger, D; Ohashi, P S; Hengartner, H; Zinkernagel, R M; Mak, T W; Lang, K S

2013-01-18

125

Cardiac reactive oxygen species after traumatic brain injury  

PubMed Central

Background Cardiovascular complications after traumatic brain injury (TBI) contribute to morbidity and mortality and may provide a target for therapy. We examined blood pressure and left ventricle contractility after TBI, and tested the hypothesis that beta-adrenergic blockade would decrease oxidative stress after TBI. Material and Methods Rodents received fluid-percussion injury or sham surgery, confirmed with magnetic resonance imaging (MRI) and histopathology. We followed recovery with sensorimotor coordination testing and blood pressure measurements. We assessed left ventricular ejection fraction using ECG-gated cardiac MRI and measured myocardial reactive oxygen species (ROS) with dihydroethidium. We randomized additional TBI and sham animals to post-operative treatment with propranolol or control, for measurement of ROS. Results Blood pressure and cardiac contractility were elevated 48 hours after TBI. Myocardial tissue sections showed increased ROS. Treatment with propranolol diminished ROS levels following TBI. Conclusions TBI is associated with increased cardiac contractility and myocardial ROS; decreased myocardial ROS after beta-blockade suggests that sympathetic stimulation is a mechanism of oxidative stress.

Larson, Brett E; Stockwell, David W.; Boas, Stefan; Andrews, Trevor; Wellman, George C.; Lockette, Warren; Freeman, Kalev

2011-01-01

126

Reactive oxygen species delay control of lymphocytic choriomeningitis virus  

PubMed Central

Cluster of differentiation (CD)8+ T cells are like a double edged sword during chronic viral infections because they not only promote virus elimination but also induce virus-mediated immunopathology. Elevated levels of reactive oxygen species (ROS) have been reported during virus infections. However, the role of ROS in T-cell-mediated immunopathology remains unclear. Here we used the murine lymphocytic choriomeningitis virus to explore the role of ROS during the processes of virus elimination and induction of immunopathology. We found that virus infection led to elevated levels of ROS producing granulocytes and macrophages in virus-infected liver and spleen tissues that were triggered by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Lack of the regulatory subunit p47phox of the NADPH oxidase diminished ROS production in these cells. While CD8+ T cells exhibited ROS production that was independent of NADPH oxidase expression, survival and T-cell function was elevated in p47phox-deficient (Ncf1?/?) mice. In the absence of p47phox, enhanced T-cell immunity promoted virus elimination and blunted corresponding immunopathology. In conclusion, we find that NADPH-mediated production of ROS critically impairs the immune response, impacting elimination of virus and outcome of liver cell damage.

Lang, P A; Xu, H C; Grusdat, M; McIlwain, D R; Pandyra, A A; Harris, I S; Shaabani, N; Honke, N; Kumar Maney, S; Lang, E; Pozdeev, V I; Recher, M; Odermatt, B; Brenner, D; Haussinger, D; Ohashi, P S; Hengartner, H; Zinkernagel, R M; Mak, T W; Lang, K S

2013-01-01

127

Targeted modulation of reactive oxygen species in the vascular endothelium  

PubMed Central

‘Endothelial cells lining vascular luminal surface represent an important site of signaling and injurious effects of reactive oxygen species (ROS) produced by other cells and endothelium itself in ischemia, inflammation and other pathological conditions. Targeted delivery of ROS modulating enzymes conjugated with antibodies to endothelial surface molecules (vascular immunotargeting) provides site-specific interventions in the endothelial ROS, unattainable by other formulations including PEG-modified enzymes. Targeting of ROS generating enzymes (e.g., glucose oxidase) provides ROS- and site-specific models of endothelial oxidative stress, whereas targeting of antioxidant enzymes SOD and catalase offers site-specific quenching of superoxide anion and H2O2. These targeted antioxidant interventions help to clarify specific role of endothelial ROS in vascular and pulmonary pathologies and provide basis for design of targeted therapeutics for treatment of these pathologies. In particular, antibody/catalase conjugates alleviate acute lung ischemia/reperfusion injury, whereas antibody/SOD conjugates inhibit ROS-mediated vasoconstriction and inflammatory endothelial signaling. Encapsulation in protease-resistant, ROS-permeable carriers targeted to endothelium prolongs protective effects of antioxidant enzymes, further diversifying the means for targeted modulation of endothelial ROS.

Shuvaev, Vladimir V.; Muzykantov, Vladimir R.

2012-01-01

128

Targeted modulation of reactive oxygen species in the vascular endothelium  

PubMed Central

Endothelial cells lining vascular luminal surface represent an important site of signaling and injurious effects of reactive oxygen species (ROS) produced by other cells and endothelium itself in ischemia, inflammation and other pathological conditions. Targeted delivery of ROS modulating enzymes conjugated with antibodies to endothelial surface molecules (vascular immunotargeting) provides site-specific interventions in the endothelial ROS, unattainable by other formulations including PEG-modified enzymes. Targeting of ROS generating enzymes (e.g., glucose oxidase) provides ROS- and site-specific models of endothelial oxidative stress, whereas targeting of antioxidant enzymes SOD and catalase offers site-specific quenching of superoxide anion or/and H2O2. These targeted antioxidant interventions help to clarify specific role of endothelial ROS in vascular and pulmonary pathologies and provide basis for design of targeted therapeutics for treatment of these pathologies. In particular, antibody/catalase conjugates alleviate acute lung ischemia/reperfusion injury, whereas antibody/SOD conjugates inhibit ROS-mediated vasoconstriction and inflammatory endothelial signaling. Encapsulation in protease-resistant, ROS-permeable carriers targeted to endothelium prolongs protective effects of antioxidant enzymes, further diversifying the means for targeted modulation of endothelial ROS.

Shuvaev, Vladimir V.; Muzykantov, Vladimir R.

2011-01-01

129

Reactive Oxygen Species and Respiratory Plasticity Following Intermittent Hypoxia  

PubMed Central

The neural network controlling breathing exhibits plasticity in response to environmental or physiological challenges. For example, while hypoxia initiates rapid and robust increases in respiratory motor output to defend against hypoxemia, it also triggers persistent changes, or plasticity, in chemosensory neurons and integrative pathways that transmit brainstem respiratory activity to respiratory motor neurons. Frequently studied models of hypoxia-induced respiratory plasticity include: 1) carotid chemosensory plasticity and metaplasticity induced by chronic intermittent hypoxia (CIH), and 2) acute intermittent hypoxia (AIH) induced phrenic long-term facilitation (pLTF) in naïve and CIH preconditioned rats. These forms of plasticity share some mechanistic elements, although they differ in anatomical location and the requirement for CIH preconditioning. Both forms of plasticity require serotonin receptor activation and formation of reactive oxygen species (ROS). While the cellular sources and targets of ROS are not well known, recent evidence suggests that ROS modify the balance of protein phosphatase and kinase activities, shifting the balance towards net phosphorylation and favoring cellular reactions that induce and/or maintain plasticity. Here, we review possible sources of ROS, and the impact of ROS on phosphorylation events relevant to respiratory plasticity.

MacFarlane, P.M.; Wilkerson, J.E.R.; Lovett-Barr, M.R.; Mitchell, G.S.

2008-01-01

130

Dissolved Oxygen Demand of Reduced Chemical Species in the Water Column of Sebasticook Lake, Maine.  

National Technical Information Service (NTIS)

Fifty water column profiles were sampled at Sebasticook Lake, Penobscot County, Maine to determine the impact of reduced chemical species on the dissolved oxygen content of this culturally eutrophic lake. Reduced chemical species measured were CH4, Fe(+2)...

F. P. Liotta

1979-01-01

131

Electrolyzed–Reduced Water Scavenges Active Oxygen Species and Protects DNA from Oxidative Damage  

Microsoft Academic Search

Active oxygen species or free radicals are considered to cause extensive oxidative damage to biological macromolecules, which brings about a variety of diseases as well as aging. The ideal scavenger for active oxygen should be ‘active hydrogen’. ‘Active hydrogen’ can be produced in reduced water near the cathode during electrolysis of water. Reduced water exhibits high pH, low dissolved oxygen

Sanetaka Shirahata; Shigeru Kabayama; Mariko Nakano; Takumi Miura; Kenichi Kusumoto; Miho Gotoh; Hidemitsu Hayashi; Kazumichi Otsubo; Shinkatsu Morisawa; Yoshinori Katakura

1997-01-01

132

Studies on the photostoragechemiluminescence of aromatic ketones with reactive oxygen species  

Microsoft Academic Search

It is believed that chemiluminescence (CL) of photolyzed aromatic compounds proceeds in alkaline media and in the presence of oxygen, with various reactive oxygen species (ROS). In order to prove this hypothesis we have investigated the contribution of chemically produced ROS, such as hydroxyl radicals, singlet oxygen as well as superoxide radical anions on CL reactions of photolyzed aromatic compounds.

K Papadopoulos; T Triantis; K Tsagaraki; D Dimotikali; N Iftimie; A Meghea

2002-01-01

133

Role of reactive oxygen species in apoptosis: implications for cancer therapy  

Microsoft Academic Search

Reactive oxygen species are widely generated in biological systems. Consequently humans have evolved antioxidant defence systems that limit their production. Intracellular production of active oxygen species such as –OH, O2? and H2O2 is associated with the arrest of cell proliferation. Similarly, generation of oxidative stress in response to various external stimuli has been implicated in the activation of transcription factors

José M Matés; Francisca M Sánchez-Jiménez

2000-01-01

134

Roles of reactive oxygen species and antioxidants in ovarian toxicity.  

PubMed

Proper functioning of the ovary is critical to maintain fertility and overall health, and ovarian function depends on the maintenance and normal development of ovarian follicles. This review presents evidence about the potential impact of oxidative stress on the well-being of primordial, growing and preovulatory follicles, as well as oocytes and early embryos, examining cell types and molecular targets. Limited data from genetically modified mouse models suggest that several antioxidant enzymes that protect cells from reactive oxygen species (ROS) may play important roles in follicular development and/or survival. Exposures to agents known to cause oxidative stress, such as gamma irradiation, chemotherapeutic drugs, or polycyclic aromatic hydrocarbons, induce rapid primordial follicle loss; however, the mechanistic role of ROS has received limited attention. In contrast, ROS may play an important role in the initiation of apoptosis in antral follicles. Depletion of glutathione leads to atresia of antral follicles in vivo and apoptosis of granulosa cells in cultured antral follicles. Chemicals, such as cyclophosphamide, dimethylbenzanthracene, and methoxychlor, increase proapoptotic signals, preceded by increased ROS and signs of oxidative stress, and cotreatment with antioxidants is protective. In oocytes, glutathione levels change rapidly during progression of meiosis and early embryonic development, and high oocyte glutathione at the time of fertilization is required for male pronucleus formation and for embryonic development to the blastocyst stage. Because current evidence suggests that oxidative stress can have significant negative impacts on female fertility and gamete health, dietary or pharmacological intervention may prove to be effective strategies to protect female fertility. PMID:22034525

Devine, Patrick J; Perreault, Sally D; Luderer, Ulrike

2012-02-09

135

Mechanism of teratogenesis: electron transfer, reactive oxygen species, and antioxidants.  

PubMed

Teratogenesis has been a topic of increasing interest and concern in recent years, generating controversy in association with danger to humans and other living things. A veritable host of chemicals is known to be involved, encompassing a wide variety of classes, both organic and inorganic. Contact with these chemicals is virtually unavoidable due to contamination of air, water, ground, food, beverages, and household items, as well as exposure to medicinals. The resulting adverse effects on reproduction are numerous. There is uncertainty regarding the mode of action of these chemicals, although various theories have been advanced, e.g., disruption of the central nervous system (CNS), DNA attack, enzyme inhibition, interference with hormonal action, and insult to membranes, proteins, and mitochondria. This review provides extensive evidence for involvement of oxidative stress (OS) and electron transfer (ET) as a unifying theme. Successful application of the mechanistic approach is made to all of the main classes of toxins, in addition to large numbers of miscellaneous types. We believe it is not coincidental that the vast majority of these substances incorporate ET functionalities (quinone, metal complex, ArNO2, or conjugated iminium) either per se or in metabolites, potentially giving rise to reactive oxygen species (ROS) by redox cycling. Some categories, e.g., peroxides and radiation, appear to generate ROS by non-ET routes. Other mechanisms are briefly addressed; a multifaceted approach to mode of action appears to be the most logical. Our framework should increase understanding and contribute to preventative measures, such as use of antioxidants. PMID:17315244

Kovacic, Peter; Somanathan, Ratnasamy

2006-12-01

136

Role of reactive oxygen species-mediated signaling in aging.  

PubMed

Abstract Significance: Redox biology is a rapidly developing area of research due to the recent evidence for general importance of redox control for numerous cellular functions under both physiological and pathophysiological conditions. Understanding of redox homeostasis is particularly relevant to the understanding of the aging process. The link between reactive oxygen species (ROS) and accumulation of age-associated oxidative damage to macromolecules is well established, but remains controversial and applies only to a subset of experimental models. In addition, recent studies show that ROS may function as signaling molecules and that dysregulation of this process may also be linked to aging. Recent Advances: Many protein factors and pathways that control ROS production and scavenging, as well as those that regulate cellular redox homeostasis, have been identified. However, much less is known about the mechanisms by which redox signaling pathways influence longevity. In this review, we discuss recent advances in the understanding of the molecular basis for the role of redox signaling in aging. Critical Issues: Recent studies allowed identification of previously uncharacterized redox components and revealed complexity of redox signaling pathways. It would be important to identify functions of these components and elucidate how distinct redox pathways are integrated with each other to maintain homeostatic balance. Future Directions: Further characterization of processes that coordinate redox signaling, redox homeostasis, and stress response pathways should allow researchers to dissect how their dysregulation contributes to aging and pathogenesis of various age-related diseases, such as diabetes, cancer and neurodegeneration. Antioxid. Redox Signal. 19, 1362-1372. PMID:22901002

Labunskyy, Vyacheslav M; Gladyshev, Vadim N

2012-09-20

137

Biphasic regulation of angiogenesis by reactive oxygen species.  

PubMed

Reactive oxygen species (ROS) are believed to be important molecules in the regulation of angiogenesis. However, direct evidence is obtained from hydrogen peroxide only. The comparison of superoxide anion (O2-), hydrogen peroxide (H202) and hydroxyl radical (HO*) effects on angiogenesis in one angiogenic model were studied. Tube formation, migration and adhesion of endothelial cells were enhanced with a low concentration of O2 generated by 500 [microM xanthine (X) and 1 mU/ml xanthine oxidase (XO), but significantly inhibited as the XO increased to 10 mU/ml or more. Low concentrations of H2O2 (0.01-1 microM) induced tube formation and the maximal tube formation was achieved at 0.1 microM which also induced cell migration and adhesion, while high concentrations of H2O2 (100 microM) inhibited tube formation and cell migration. Both H2O2 and O2 inhibited cell proliferation at high concentration only. HO* at low concentration neither inhibited nor stimulated the tube formation, cell proliferation and migration but inhibited at high concentration. The effects of O2 were significantly abolished by catalase (CAT) alone or in combination with superoxide dismutase (SOD), but not by inactive CAT or SOD alone. Active CAT, but not inactive CAT, also reversed the effects of H2O2. Pretreatment with GSH effectively reversed the inhibitory effects of HO*. Therefore, our results suggest that ROS have biphasic effects on angiogenesis, which indicated that pharmacologically regulating cellular ROS levels might serve as an anti-angiogenic or angiogenic principles. They also provide a theoretical basis for the development and rational use of novel angiogenic and anti-angiogenic drugs. PMID:16599264

Huang, Shuang-Sheng; Zheng, Rong-Liang

2006-03-01

138

Reactive oxygen species-regulated signaling pathways in diabetic nephropathy.  

PubMed

Diabetic nephropathy is characterized by excessive deposition of extracellular matrix (ECM) in the kidney. TGF-beta1 has been identified as the key mediator of ECM accumulation in diabetic kidney. High glucose induces TGF-beta1 in glomerular mesangial and tubular epithelial cells and in diabetic kidney. Antioxidants inhibit high glucose-induced TGF-beta1 and ECM expression in glomerular mesangial and tubular epithelial cells and ameliorate features of diabetic nephropathy, suggesting that oxidative stress plays an important role in diabetic renal injury. High glucose induces intracellular reactive oxygen species (ROS) in mesangial and tubular epithelial cells. High glucose-induced ROS in mesangial cells can be effectively blocked by inhibition of protein kinase C (PKC), NADPH oxidase, and mitochondrial electron transfer chain complex I, suggesting that PKC, NADPH oxidase, and mitochondrial metabolism all play a role in high glucose-induced ROS generation. Advanced glycation end products, TGF-beta1, and angiotensin II can also induce ROS generation and may amplify high glucose-activated signaling in diabetic kidney. Both high glucose and ROS activate signal transduction cascade (PKC, mitogen-activated protein kinases, and janus kinase/signal transducers and activators of transcription) and transcription factors (nuclear factor-kappaB, activated protein-1, and specificity protein 1) and upregulate TGF-beta1 and ECM genes and proteins. These observations suggest that ROS act as intracellular messengers and integral glucose signaling molecules in diabetic kidney. Future studies elucidating various other target molecules activated by ROS in renal cells cultured under high glucose or in diabetic kidney will allow a better understanding of the final cellular responses to high glucose. PMID:12874439

Lee, Hi Bahl; Yu, Mi-Ra; Yang, Yanqiang; Jiang, Zongpei; Ha, Hunjoo

2003-08-01

139

Dissolved-Oxygen Requirements of Three Species of Fish  

Microsoft Academic Search

Critical dissolved-oxygen levels and standard metabolic rates were determined for the bluegill, Lepomis macrochirus; largemouth bass, Micropterus salmoides; and the channel catfish, Ictalurus punctatus, at 25° C., 30° C., and 35° C. Two types of experiments were conducted: shock tests in which the dissolved oxygen was dropped rapidly from near saturation to a critically low point; and acclimation tests in

D. D. Moss; D. C. Scott

1961-01-01

140

Oxygen sensitivity of mitochondrial reactive oxygen species generation depends on metabolic conditions.  

PubMed

The mitochondrial generation of reactive oxygen species (ROS) plays a central role in many cell signaling pathways, but debate still surrounds its regulation by factors, such as substrate availability, [O2] and metabolic state. Previously, we showed that in isolated mitochondria respiring on succinate, ROS generation was a hyperbolic function of [O2]. In the current study, we used a wide variety of substrates and inhibitors to probe the O2 sensitivity of mitochondrial ROS generation under different metabolic conditions. From such data, the apparent Km for O2 of putative ROS-generating sites within mitochondria was estimated as follows: 0.2, 0.9, 2.0, and 5.0 microM O2 for the complex I flavin site, complex I electron backflow, complex III QO site, and electron transfer flavoprotein quinone oxidoreductase of beta-oxidation, respectively. Differential effects of respiratory inhibitors on ROS generation were also observed at varying [O2]. Based on these data, we hypothesize that at physiological [O2], complex I is a significant source of ROS, whereas the electron transfer flavoprotein quinone oxidoreductase may only contribute to ROS generation at very high [O2]. Furthermore, we suggest that previous discrepancies in the assignment of effects of inhibitors on ROS may be due to differences in experimental [O2]. Finally, the data set (see supplemental material) may be useful in the mathematical modeling of mitochondrial metabolism. PMID:19366681

Hoffman, David L; Brookes, Paul S

2009-04-14

141

Effects of the oxygenation level on formation of different reactive oxygen species during photodynamic therapy.  

PubMed

We examined the effect of the oxygenation level on efficacy of two photosensitizing agents, both of which target lysosomes for photodamage, but via different photochemical pathways. Upon irradiation, the chlorin termed NPe6 forms singlet oxygen in high yield while the bacteriopheophorbide WST11 forms only oxygen radicals (in an aqueous environment). Photokilling efficacy by WST11 in cell culture was impaired when the atmospheric oxygen concentration was reduced from 20% to 1%, while photokilling by NPe6 was unaffected. Studies in a cell-free system revealed that the rates of photobleaching of these agents, as a function of the oxygenation level, were correlated with results described above. Moreover, the rate of formation of oxygen radicals by either agent was more sensitive to the level of oxygenation than was singlet oxygen formation by NPe6. These data indicate that the photochemical process that leads to oxygen radical formation is more dependent on the oxygenation level than is the pathway leading to formation of singlet oxygen. PMID:23216021

Price, Michael; Heilbrun, Lance; Kessel, David

2013-01-25

142

KRIT1 Regulates the Homeostasis of Intracellular Reactive Oxygen Species  

PubMed Central

KRIT1 is a gene responsible for Cerebral Cavernous Malformations (CCM), a major cerebrovascular disease characterized by abnormally enlarged and leaky capillaries that predispose to seizures, focal neurological deficits, and fatal intracerebral hemorrhage. Comprehensive analysis of the KRIT1 gene in CCM patients has suggested that KRIT1 functions need to be severely impaired for pathogenesis. However, the molecular and cellular functions of KRIT1 as well as CCM pathogenesis mechanisms are still research challenges. We found that KRIT1 plays an important role in molecular mechanisms involved in the maintenance of the intracellular Reactive Oxygen Species (ROS) homeostasis to prevent oxidative cellular damage. In particular, we demonstrate that KRIT1 loss/down-regulation is associated with a significant increase in intracellular ROS levels. Conversely, ROS levels in KRIT1?/? cells are significantly and dose-dependently reduced after restoration of KRIT1 expression. Moreover, we show that the modulation of intracellular ROS levels by KRIT1 loss/restoration is strictly correlated with the modulation of the expression of the antioxidant protein SOD2 as well as of the transcriptional factor FoxO1, a master regulator of cell responses to oxidative stress and a modulator of SOD2 levels. Furthermore, we show that the KRIT1-dependent maintenance of low ROS levels facilitates the downregulation of cyclin D1 expression required for cell transition from proliferative growth to quiescence. Finally, we demonstrate that the enhanced ROS levels in KRIT1?/? cells are associated with an increased cell susceptibility to oxidative DNA damage and a marked induction of the DNA damage sensor and repair gene Gadd45?, as well as with a decline of mitochondrial energy metabolism. Taken together, our results point to a new model where KRIT1 limits the accumulation of intracellular oxidants and prevents oxidative stress-mediated cellular dysfunction and DNA damage by enhancing the cell capacity to scavenge intracellular ROS through an antioxidant pathway involving FoxO1 and SOD2, thus providing novel and useful insights into the understanding of KRIT1 molecular and cellular functions.

Goitre, Luca; Balzac, Fiorella; Degani, Simona; Degan, Paolo; Marchi, Saverio; Pinton, Paolo; Retta, Saverio Francesco

2010-01-01

143

Reactive Oxygen Species Regulate F-actin Dynamics in Neuronal Growth Cones and Neurite Outgrowth  

PubMed Central

Reactive oxygen species are well known for their damaging effects due to oxidation of lipids, proteins and DNA that ultimately result in cell death. Accumulating evidence indicates that reactive oxygen species also have important signaling functions in cell proliferation, differentiation, cell motility and apoptosis. Here, we tested the hypothesis whether reactive oxygen species play a physiological role in regulating F-actin structure and dynamics in neuronal growth cones. Lowering cytoplasmic levels of reactive oxygen species with a free radical scavenger, N-tert-butyl-?-phenylnitrone, or by inhibiting specific sources of reactive oxygen species, such as NADPH oxidases or lipoxygenases, reduced the F-actin content in the peripheral domain of growth cones. Fluorescent speckle microscopy revealed that these treatments caused actin assembly inhibition, reduced retrograde actin flow and increased contractility of actin structures in the transition zone referred to as arcs, possibly by activating the Rho pathway. Reduced levels of reactive oxygen species ultimately resulted in disassembly of the actin cytoskeleton. When neurons were cultured overnight in conditions of reduced free radicals, growth cone formation and neurite outgrowth were severely impaired. Therefore, we conclude that physiological levels of reactive oxygen species are critical for maintaining a dynamic F-actin cytoskeleton and controlling neurite outgrowth.

Munnamalai, Vidhya; Suter, Daniel M.

2010-01-01

144

The induction of reactive oxygen species and loss of mitochondrial Omi/HtrA2 is associated with S-nitrosoglutathione-induced apoptosis in human endothelial cells  

SciTech Connect

The pathophysiological relevance of S-nitrosoglutathione (GSNO)-induced endothelial cell injury remains unclear. The main objective of this study was to elucidate the molecular mechanisms of GSNO-induced oxidative stress in endothelial cells. Morphological evaluation through DAPI staining and propidium iodide (PI) flow cytometry was used to detect apoptosis. In cultured EA.hy926 endothelial cells, exposure to GSNO led to a time- and dose-dependent apoptotic cascade. When intracellular reactive oxygen species (ROS) production was measured in GSNO-treated cells with the fluorescent probes 5-(and-6)-carboxy-2',7'-dichlorofluorescein diacetate, we observed elevated ROS levels and a concomitant loss in mitochondrial membrane potential, indicating that GSNO-induced death signaling is mediated through a ROS-mitochondrial pathway. Importantly, we found that peroxynitrite formation and Omi/HtrA2 release from mitochondria were involved in this phenomenon, whereas changes of death-receptor dependent signaling were not detected in the same context. The inhibition of NADPH oxidase activation and Omi/HtrA2 by a pharmacological approach provided significant protection against caspase-3 activation and GSNO-induced cell death, confirming that GSNO triggers the death cascade in endothelial cells in a mitochondria-dependent manner. Taken together, our results indicate that ROS overproduction and loss of mitochondrial Omi/HtrA2 play a pivotal role in reactive nitrogen species-induced cell death, and the modulation of these pathways can be of significant therapeutic benefit.

Liu Qibing; Liu Lulu [Institute of Pharmacology, Toxicology and Biochemical Pharmaceutics, Zhejiang University, Hangzhou, 310058 (China); Lu Yingmei [Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai (Japan); Tao Rongrong; Huang Jiyun [Institute of Pharmacology, Toxicology and Biochemical Pharmaceutics, Zhejiang University, Hangzhou, 310058 (China); Shioda, Norifumi; Moriguchi, Shigeki; Fukunaga, Kohji [Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai (Japan); Han Feng, E-mail: changhuahan@zju.edu.c [Institute of Pharmacology, Toxicology and Biochemical Pharmaceutics, Zhejiang University, Hangzhou, 310058 (China); Lou Yijia, E-mail: yijialou@zju.edu.c [Institute of Pharmacology, Toxicology and Biochemical Pharmaceutics, Zhejiang University, Hangzhou, 310058 (China)

2010-05-01

145

Decreased oxygen tension lowers reactive oxygen species and apoptosis and inhibits osteoblast matrix mineralization through changes in early osteoblast differentiation.  

PubMed

Accumulating data show that oxygen tension can have an important effect on cell function and fate. We used the human pre-osteoblastic cell line SV-HFO, which forms a mineralizing extracellular matrix, to study the effect of low oxygen tension (2%) on osteoblast differentiation and mineralization. Mineralization was significantly reduced by 60-70% under 2% oxygen, which was paralleled by lower intracellular levels of reactive oxygen species (ROS) and apoptosis. Following this reduction in ROS the cells switched to a lower level of protection by down-regulating their antioxidant enzyme expression. The downside of this is that it left the cells more vulnerable to a subsequent oxidative challenge. Total collagen content was reduced in the 2% oxygen cultures and expression of matrix genes and matrix-metabolizing enzymes was significantly affected. Alkaline phosphatase activity and RNA expression as well as RUNX2 expression were significantly reduced under 2% oxygen. Time phase studies showed that high oxygen in the first phase of osteoblast differentiation and prior to mineralization is crucial for optimal differentiation and mineralization. Switching to 2% or 20% oxygen only during mineralization phase did not change the eventual level of mineralization. In conclusion, this study shows the significance of oxygen tension for proper osteoblast differentiation, extra cellular matrix (ECM) formation, and eventual mineralization. We demonstrated that the major impact of oxygen tension is in the early phase of osteoblast differentiation. Low oxygen in this phase leaves the cells in a premature differentiation state that cannot provide the correct signals for matrix maturation and mineralization. PMID:21604266

Nicolaije, Claudia; Koedam, Marijke; van Leeuwen, Johannes P T M

2012-04-01

146

Reactive oxygen species controllable non-thermal helium plasmas for evaluation of plasmid DNA strand breaks  

NASA Astrophysics Data System (ADS)

Non-thermal, oxygen-rich helium plasmas were investigated to achieve an enhanced reactive oxygen species concentration at low voltage driving conditions. A non-thermal plasma device was fabricated based on a theta-shaped tube, and its potential was investigated for use in topological alteration of plasmid DNA. The optical emission spectra of the plasma showed that the oxygen flow affected the plasma properties, even though an oxygen plasma was not produced. The plasmid DNA strand breaks became more significant with the addition of oxygen flow to the helium in a single hollow, theta-shaped tube with other experimental conditions being unchanged.

Young Kim, Jae; Lee, Dong-Hoon; Ballato, John; Cao, Weiguo; Kim, Sung-O.

2012-11-01

147

Active oxygen species mediate asbestos fiber uptake by tracheal epithelial cells  

SciTech Connect

To examine the mechanism whereby asbestos fibers penetrate tracheal epithelial cells, we exposed rat tracheal explants to amosite asbestos alone, or with varying concentrations of substances that scavenge active oxygen species (catalase and superoxide dismutase) or prevent formation of active oxygen species (deferoxamine). All three agents decreased asbestos fiber uptake in a dose-response fashion, but no agent provided complete protection against fiber penetration. We conclude that uptake of amosite asbestos fibers is mediated in part by active oxygen species (most likely OH.), but that other mechanisms of fiber uptake must also exist.

Hobson, J.; Wright, J.L.; Churg, A. (Univ. of British Columbia, Vancouver (Canada))

1990-10-01

148

Structure Effect on Antioxidant Activity of Catecholamines toward Singlet Oxygen and Other Reactive Oxygen Species in vitro  

PubMed Central

The reactivity of catecholamine neurotransmitters and the related metabolites were precisely investigated toward 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and reactive oxygen species. Catecholamines reacted immediately with DPPH radicals, their reactivity being stronger than that of ascorbic acid as a reference. Superoxide scavenging activities of catecholamines determined by WST-1 and electron spin resonance (ESR) spin trapping methods were also high. Whereas tyrosine, the dopamine precursor showed no reactivity toward superoxide. The reactivity toward singlet oxygen was evaluated by observing specific photon emission from singlet oxygen. The results revealed that reactivity of catecholamines was markedly higher than that of sodium azide, and catechin as catechol reference. The reaction of catecholamines and singlet oxygen was further studied by ESR using 55-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trapping reagent and rose bengal as photosensitizer. DMPO-OH signal of epinephrine was significantly small compared to other catecholamines, catechin, and 4-methylcatechol as a reference compound and was as small as that of tyrosine. The signal formation was totally dependent on singlet oxygen, and the presence of catechol compounds. These results indicated that epinephrine is the most potent singlet oxygen quencher than other catecholamines, and the secondary amino group in its alkyl side chain could play a role in unique singlet oxygen quenching property of epinephrine.

Shimizu, Takako; Nakanishi, Yuji; Nakahara, Meiko; Wada, Naoki; Moro-oka, Yoshihiko; Hirano, Toru; Konishi, Tetsuya; Matsugo, Seiichi

2010-01-01

149

Fluorescence probes used for detection of reactive oxygen species  

Microsoft Academic Search

Endogenously produced pro-oxidant reactive species are essential to life, being involved in several biological functions. However, when overproduced (e.g. due to exogenous stimulation), or when the levels of antioxidants become severely depleted, these reactive species become highly harmful, causing oxidative stress through the oxidation of biomolecules, leading to cellular damage that may become irreversible and cause cell death. The scientific

Ana Gomes; Eduarda Fernandes; José L. F. C. Lima

2005-01-01

150

Chemistry and biology of reactive oxygen species in signaling or stress responses  

Microsoft Academic Search

Reactive oxygen species (ROS) are a family of molecules that are continuously generated, transformed and consumed in all living organisms as a consequence of aerobic life. The traditional view of these reactive oxygen metabolites is one of oxidative stress and damage that leads to decline of tissue and organ systems in aging and disease. However, emerging data show that ROS

Bryan C Dickinson; Christopher J Chang

2011-01-01

151

Prostaglandins and Radical Oxygen Species Are Involved in Microvascular Effects of Hyperoxia  

Microsoft Academic Search

Hyperoxia causes vasoconstriction in most tissues, by mechanisms that are not fully understood. We investigated microvascular effects of breathing 100% oxygen in healthy volunteers, using iontophoresis to deliver acetylcholine (ACh) and sodium nitroprusside (SNP). Aspirin and vitamin C were used to test for involvement of prostaglandins and radical oxygen species. Forearm skin perfusion was measured using laser Doppler perfusion imaging.

A. Rousseau; E. Tesselaar; J. Henricson; F. Sjöberg

2010-01-01

152

Bradykinin and adenosine receptors mediate desflurane induced postconditioning in human myocardium: role of reactive oxygen species  

Microsoft Academic Search

BACKGROUND: Desflurane during early reperfusion has been shown to postcondition human myocardium, in vitro. We investigated the role of adenosine and bradykinin receptors, and generation of radical oxygen species in desflurane-induced postconditioning in human myocardium. METHODS: We recorded isometric contraction of human right atrial trabeculae hanged in an oxygenated Tyrode's solution (34 degrees Celsius, stimulation frequency 1 Hz). After a

Sandrine Lemoine; Clément Buléon; René Rouet; Calin Ivascau; Gérard Babatasi; Massimo Massetti; Jean-Louis Gérard; Jean-Luc Hanouz

2010-01-01

153

On the Nature of the Oxygen Species Absorbed on Oxide Surfaces.  

National Technical Information Service (NTIS)

Electron spin resonance studies of adsorbed oxygen on oxide surfaces (principally ZnO) have been out using 17O enriched oxygen. An ESR triplet attributed to an O2(-) species at the surface was recently reported by this laboratory. Under identical experime...

M. Codell J. Weisberg H. Gisser R. D. Iyengar

1969-01-01

154

?-glutamyltransferase dependent generation of reactive oxygen species from a glutathione\\/transferrin system  

Microsoft Academic Search

In the presence of molecular oxygen and iron or copper ions, a number of antioxidants paradoxically generate reactive oxygen species (ROS) leading to free radical damage of nucleic acids and oxidative modification of lipids and proteins. The present work demonstrates that the combination of three components, which are often considered as part of an antioxidant protection system, can generate ROS.

Ryszard Drozdz; Christine Parmentier; Houda Hachad; Pierre Leroy; Maria Wellman

1998-01-01

155

NADPH oxidase(s): new source(s) of reactive oxygen species in the vascular system?  

Microsoft Academic Search

Reactive oxygen species play an important role in a variety of (patho)physiological vascular processes. Recent publications have produced evidence of a role for putative non-phagocyte NADP oxidase(s) in the vascular production of reactive oxygen species. In the present review, we discuss the detection of the different components of NADP oxidase(s) in the vascular system, together with the putative role of

L Van Heerebeek; C. Meischl; W. Stooker; C. J. L. M. Meijer; H. W. M. Niessen; D. Roos

2002-01-01

156

Increased intracellular reactive oxygen species in patients with end-stage renal failure: Effect of hemodialysis  

Microsoft Academic Search

Increased intracellular reactive oxygen species in patients with end-stage renal failure: Effect of hemodialysis.BackgroundReactive oxygen species (ROS) have been implicated in various forms of cellular injury. ROS may cause cell damage and are involved in the pathophysiology of several diseases, including atherosclerosis and chronic inflammation.MethodsDisturbances of intracellular ROS levels were investigated in 28 patients with end-stage renal failure. The intracellular

Martin Tepel; Martin Echelmeyer; Nelson N Orie; Walter Zidek

2000-01-01

157

Reactive oxygen species as glucose signaling molecules in mesangial cells cultured under high glucose  

Microsoft Academic Search

Reactive oxygen species as glucose signaling molecules in mesangial cells cultured under high glucose.BackgroundOxidative stress is one of the important mediators of vascular complications in diabetes including nephropathy. High glucose (HG) generates reactive oxygen species (ROS) as a result of glucose auto-oxidation, metabolism, and formation of advanced glycosylation end products. The concept of ROS-induced tissue injury has recently been revised

Hunjoo Ha; Hi Bahl Lee

2000-01-01

158

Hemoglobin induces colon cancer cell proliferation by release of reactive oxygen species  

Microsoft Academic Search

AIM: To study whether hemoglobin could amplify colon cancer cell proliferation via reactive oxygen species (ROS) production. METHODS: Colon cancer cell line HT-29 was grown in the conventional method using RPMI1640 media. The viability of the cells was measured using the colorimetric MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazo- lium bromide) assay after adding hemoglobin. We de- termined reactive oxygen species levels to

Ryung-Ah Lee; Hyun-Ah Kim; Bo-Young Kang; Kwang-Ho Kim

2006-01-01

159

Using oxygen species to measure marine production in Drake Passage  

Microsoft Academic Search

Marine biological production is key to understanding the global carbon cycle, particularly the role of the Southern Ocean as a sink of CO2. Measurements of oxygen in the surface ocean allow quantifying marine biological productivity, since CO2 and O2 are linked via photosynthesis and respiration. Measurements of O2\\/Ar ratios and dissolved O2 isotopologues, together with wind-speed gas exchange parameterizations, give

Karel Castro Morales; Nicolas Cassar; Michael Bender; Jan Kaiser

2010-01-01

160

Antioxidants from grape seeds protect hair against reactive oxygen species  

Microsoft Academic Search

Summary Oxygen based radicals are predominantly generated in the water phase. Therefore, it is very important to use not only lipophilic antioxidants but also water-soluble radical scavengers in cosmetic formula- tions. Vitamin C, glutathion and different enzymes are natural water-soluble antioxidants. Unfortunately, most of them are not stable in cosmetic formulations. We studied a new water-soluble antioxidant based on procyanidins

F. Zülli; E. Belser; M. Neuenschwander; R. Muggli

161

Peripartum Cardiomyopathy: Role of STAT3 and Reactive Oxygen Species  

Microsoft Academic Search

\\u000a Enhanced oxidative stress related to high metabolic turnover and elevated tissue oxygen requirements are the characteristic\\u000a physiological state in pregnancy. In women with noneventful pregnancy and peripartum periods, this process appears to be paralleled\\u000a by an increase in systemic antioxidant capacity. While these biochemical changes may not have pathophysiological consequences\\u000a in healthy women, they may sensitize women with additional risk

Denise Hilfiker-Kleiner; Arash Haghikia; Andres Hilfiker

162

Disturbance of reactive oxygen species homeostasis induces atypical tubulin polymer formation and affects mitosis in root-tip cells of Triticum turgidum and Arabidopsis thaliana.  

PubMed

In this study, the effects of disturbance of the reactive oxygen species (ROS) homeostasis on the organization of tubulin cytoskeleton in interphase and mitotic root-tip cells of Triticum turgidum and Arabidopsis thaliana were investigated. Reduced ROS levels were obtained by treatment with diphenylene iodonium (DPI) and N-acetyl-cysteine, whereas menadione was applied to achieve ROS overproduction. Both increased and low ROS levels induced: (a) Macrotubule formation in cells with low ROS levels and tubulin paracrystals under oxidative stress. The protein MAP65-1 was detected in treated cells, exhibiting a conformation comparable to that of the atypical tubulin polymers. (b) Disappearance of microtubules (MTs). (c) Inhibition of preprophase band formation. (d) Delay of the nuclear envelope breakdown at prometaphase. (e) Prevention of perinuclear tubulin polymer assembly in prophase cells. (f) Loss of bipolarity of prophase, metaphase and anaphase spindles. Interestingly, examination of the A. thaliana rhd2/At respiratory burst oxidase homolog C (rbohc) NADPH oxidase mutant, lacking RHD2/AtRBOHC, gave comparable results. Similarly to DPI, the decreased ROS levels in rhd2 root-tip cells, interfered with MT organization and induced macrotubule assembly. These data indicate, for first time in plants, that ROS are definitely implicated in: (a) mechanisms controlling the assembly/disassembly of interphase, preprophase and mitotic MT systems and (b) mitotic spindle function. The probable mechanisms, by which ROS affect these processes, are discussed. PMID:21976360

Livanos, Pantelis; Galatis, Basil; Quader, Hartmut; Apostolakos, Panagiotis

2011-10-18

163

Reactive oxygen species-mediated mitochondrial pathway is involved in Baohuoside I-induced apoptosis in human non-small cell lung cancer.  

PubMed

Baohuoside I (also known as Icariside II) is a flavonoid isolated from Epimedium koreanum Nakai. Although Baohuoside I exhibits anti-inflammatory and anti-cancer activities, its molecular targets/pathways in human lung cancer cells are poorly understood. Therefore, in the present study, we investigated the usefulness of Baohuoside I as a potential apoptosis-inducing cytotoxic agent using human adenocarcinoma alveolar basal epithelial A549 cells as in vitro model. The apoptosis induced by Baohuoside I in A549 cells was confirmed by annexin V/propidium iodide double staining, cell cycle analysis and dUTP nick end labeling. Further research revealed that Baohuoside I accelerated apoptosis through the mitochondrial apoptotic pathway, involving the increment of BAX/Bcl-2 ratio, dissipation of mitochondrial membrane potential, transposition of cytochrome c, caspase 3 and caspase 9 activation, degradation of poly (ADP-ribose) polymerase and the over-production of reactive oxygen species (ROS). A pan-caspase inhibitor, Z-VAD-FMK, only partially prevented apoptosis induced by Baohuoside I, while NAC, a scavenger of ROS, diminished its effect more potently. In addition, the apoptotic effect of Baohuoside I was dependent on the activation of ROS downstream effectors, JNK and p38(MAPK), which could be almost abrogated by using inhibitors SB203580 (an inhibitor of p38(MAPK)) and SP600125 (an inhibitor of JNK). These findings suggested that Baohuoside I might exert its cytotoxic effect via the ROS/MAPK pathway. PMID:22687635

Song, Jie; Shu, Luan; Zhang, Zhenhai; Tan, Xiaobin; Sun, E; Jin, Xin; Chen, Yan; Jia, Xiaobin

2012-06-09

164

Differential response of young and adult leaves to herbicide 2,4-dichlorophenoxyacetic acid in pea plants: role of reactive oxygen species.  

PubMed

In this work the differential response of adult and young leaves from pea (Pisum sativum L.) plants to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) (23 mm) applied by foliar spraying was investigated. The concentration of 2,4-D (23 mm) and the time of treatment (72 h) were previously optimized in order to visualize its toxic effects on pea plants. Under these conditions, the herbicide induced severe disturbances in mesophyll cells structure and proliferation of vascular tissue in young leaves and increased acyl-CoA oxidase (ACX), xanthine oxidase (XOD) and lipoxygenase (LOX) activities in young leaves, and only ACX and LOX in adult leaves. This situation produced reactive oxygen species (ROS) over-accumulation favoured by the absence of significant changes in the enzymatic antioxidants, giving rise to oxidative damages to proteins and membrane lipids. An increase of ethylene took place in both young and adult leaves and the induction of genes encoding the stress proteins, PRP4A and HSP 71,2, was observed mainly in young leaves. These results suggest that ROS overproduction is a key factor in the effect of high concentrations of 2,4-D, and ROS can trigger a differential response in young and adult leaves, either epinasty development in young leaves or senescence processes in adult tissues. PMID:21707656

Pazmiño, Diana M; Rodríguez-Serrano, María; Romero-Puertas, María C; Archilla-Ruiz, Angustias; Del Río, Luis A; Sandalio, Luisa M

2011-07-26

165

Prooxidant action of hinokitiol: hinokitiol-iron dependent generation of reactive oxygen species.  

PubMed

Hinokitiol (alpha-thujaplicin, 2-hydroxy-4-isopropyl-2,4,6-cycloheptatrien-1-one), one of the tropolone compounds purified from the woods of Chamaecyparis and Thujopsis (hinoki and hiba), produced reactive oxygen species as a complex with transition metals. Hinokitiol/iron complex inactivated aconitase, the most sensitive enzyme to reactive oxygen, whereas it did not affect aldolase and glyceraldehyde 3-phosphate dehydrogenase. The inactivation of aconitase was iron-dependent, and prevented by TEMPOL, a scavenger of reactive oxygen species and superoxide dismutase, suggesting that the hinokitiol/iron-mediated generation of superoxide anion is responsible for the inactivation of aconitase. Addition of hinokitiol effectively enhanced the ascorbate/copper-mediated formation of 8-hydroxy-2'-deoxyguanosine in DNA. Cytotoxic effect of hinokitiol can be explained by its prooxidant properties: hinokitiol/transition metal complex generates reactive oxygen species causing inactivation of aconitase and production of hydroxyl radical resulting in the formation of DNA base adduct. PMID:16364055

Murakami, Keiko; Ohara, Yoshihiro; Haneda, Miyako; Tsubouchi, Ryoko; Yoshino, Masataka

2005-12-01

166

Reactivities of radicals of adenine and guanine towards reactive oxygen species and reactive nitrogen oxide species: OH and NO 2  

Microsoft Academic Search

Reactions of radicals of the DNA bases with reactive oxygen species and reactive nitrogen oxide species produce mutagenic products. We have studied reactivities of all the carbon sites of radicals of adenine A(-H) and guanine G(-H) obtained by removal of H-atoms from their nitrogen sites towards OH and NO2. We studied stabilities of A(-H) and G(-H) and binding energies of

Neha Agnihotri; P. C. Mishra

2011-01-01

167

Using oxygen species to measure marine production in Drake Passage  

NASA Astrophysics Data System (ADS)

Marine biological production is key to understanding the global carbon cycle, particularly the role of the Southern Ocean as a sink of CO2. Measurements of oxygen in the surface ocean allow quantifying marine biological productivity, since CO2 and O2 are linked via photosynthesis and respiration. Measurements of O2/Ar ratios and dissolved O2 isotopologues, together with wind-speed gas exchange parameterizations, give estimates of biological oxygen air-sea fluxes (Fbio) and gross photosynthetic production (G) in the mixed layer (zmix). In the absence of vertical mixing, Fbio can be used as a proxy for net community production (N). O2/Ar ratios and O2 concentrations were measured continuously in the uncontaminated seawater supply on board the RRS James Clark Ross along two sections across Drake Passage (DP). The DP1 section (southbound, 27 February-3 March 2007) represented mid-summer; DP2 represented early autumn (northbound, 12-15 April, 2007). The time difference between the two transects was 40 days. Weighted average gas exchange rates were calculated using the WOCE-NODC ocean mixed layer depth climatology and ECMWF wind speeds over 60 days prior to sample collection. The WOCE-NODC climatology shows a deepening of the zmix by on average 46 m within 40 days. The sea surface temperature decreased about 2.4 °C from DP1 to DP2. This reflects the seasonal transition from late summer to early autumn. In agreement with previous observations, we observed a strong north-south gradient of biological oxygen production in the DP. Our results also show high temporal variability over the course of 40 days. During late summer, the physical supersaturation contributes to about 3.6% of the total O2 supersaturation (?O2) for the Subantarctic and Polar Frontal Zones (SAZ and PFZ, respectively). In the other hand, the biological O2 supersaturation (?O2/Ar) showed mainly positive and homogeneous values (~1%) along the Antarctic Zone and Southern Antarctic Circumpolar Current Zone (AZ and SACCZ, respectively). This observation reflects predominantly a biological O2 production, associated with a shallow summer zmix (66 m), rather than due to physical processes (average Fbio of 9 mmol m-2 d-1 and G of 28 mmol m-2 d-1). The situation is inverted 40 days later during early autumn, when sea ice begins to form and zmix deepens (112 m). In AZ and SACCZ, Fbio and G decreased to -7 mmol m-2 d-1 and 10 mmol m-2 d-1, respectively. It is unclear whether net heterotrophy, upwelling of O2 subsaturated waters or increased of zmix and entrainment of low oxygen waters are responsible for the negative biological oxygen flux observed in during late summer in SAZ and PFZ, and in early autumn for AZ and SACCZ. We found a higher correlation between Fbio and zmix for the DP2 section than for DP1 (R2=0.61 and 0.08, respectively). Therefore, the increase of the zmix also plays an important role for the Fbio and G pattern in the DP, suggesting the entrainment of subsurface O2 depleted waters to the upper water column at the end of the growing season. Based on our observations, we argue that seasonal variations in zmix can potentially explain part of the meridional gradients found in the DP.

Castro Morales, Karel; Cassar, Nicolas; Bender, Michael; Kaiser, Jan

2010-05-01

168

Investigation of bacterial resistance to the immune system response: Cepacian depolymerisation by reactive oxygen species  

Microsoft Academic Search

Reactive oxygen species (ROS) are part of the weapons used by the immune system to kill and degrade infecting microorganisms. Bacteria can produce macromolecules, such as polysaccharides, that are able to scavenge ROS. Species belonging to the Burkholderia cepacia complex are involved in serious lung infection in cystic fibrosis patients and produce a characteristic polysaccharide, cepacian. The interaction between ROS

Bruno Cuzzi; Paola Cescutti; Linda Furlanis; Cristina Lagatolla; Luisa Sturiale; Domenico Garozzo; Roberto Rizzo

2012-01-01

169

Distinct Signaling Pathways Respond to Arsenite and Reactive Oxygen Species in Schizosaccharomyces pombe  

Microsoft Academic Search

Exposure to certain metal and metalloid species, such as arsenic, cadmium, chromium, and nickel, has been associated with an increased risk of cancer in humans. The biological effects of these metals are thought to result from induction of reactive oxygen species (ROS) and inhibition of DNA repair enzymes, although alterations in signal transduction pathways may also be involved in tumor

M. A. Rodriguez-Gabriel; Paul Russell

2005-01-01

170

Reactive species in atmospheric pressure helium-oxygen plasmas with humid air impurities  

NASA Astrophysics Data System (ADS)

In most applications helium-based plasma jets operate in an open air environment. The presence of humid-air in the plasma jet will influence the plasma chemistry and can lead to the production of a broader range of reactive species. We explore the influence of humid air on the reactive species in rf driven atmospheric-pressure helium-oxygen mixture plasmas (helium with 5000 ppm admixture of oxygen) for wide air impurity levels of 0-500 ppm with relative humidities of from 0 to 100% using a zero-dimensional, time-dependent global model. Comparisons are made with experimental measurements in an rf driven micro-scale atmospheric pressure plasma jet and with one-dimensional semi-kinetic simulations of the same plasma jet. The evolution of species concentration is described for reactive oxygen species, metastable species, radical species and positively- and negatively-charged ions (and its clusters). Effects of the air impurity containing water humidity on electronegativity and chemical activity are clarified with particular emphasis on reactive oxygen species.

Murakami, Tomoyuki; Niemi, Kari; Gans, Timo; O'Connell, Deborah; Graham, William G.

2012-10-01

171

Detection of oxygen activation and determination of the activity of antioxidants towards reactive oxygen species by use of the chemiluminigenic probes luminol and lucigenin  

Microsoft Academic Search

Reactive oxygen metabolites can transfer, via oxygenation, the chemiluminigenic probes luminol and lucigenin to an excited state and thus induce light emission from these probes. This technique has been applied to a study of the effect of common food antioxidants on the availability of reactive oxygen species in aqueous model systems and in microsomal preparations. In all systems tested, propyl

Regine Kahl; Andreas Weimann; Sabine Weinke; Alfred G. Hildebrandt

1987-01-01

172

The role of external and matrix pH in mitochondrial reactive oxygen species generation.  

PubMed

Reactive oxygen species (ROS) generation in mitochondria as a side product of electron and proton transport through the inner membrane is important for normal cell operation as well as development of pathology. Matrix and cytosol alkalization stabilizes semiquinone radical, a potential superoxide producer, and we hypothesized that proton deficiency under the excess of electron donors enhances reactive oxygen species generation. We tested this hypothesis by measuring pH dependence of reactive oxygen species released by mitochondria. The experiments were performed in the media with pH varying from 6 to 8 in the presence of complex II substrate succinate or under more physiological conditions with complex I substrates glutamate and malate. Matrix pH was manipulated by inorganic phosphate, nigericine, and low concentrations of uncoupler or valinomycin. We found that high pH strongly increased the rate of free radical generation in all of the conditions studied, even when DeltapH=0 in the presence of nigericin. In the absence of inorganic phosphate, when the matrix was the most alkaline, pH shift in the medium above 7 induced permeability transition accompanied by the decrease of ROS production. ROS production increase induced by the alkalization of medium was observed with intact respiring mitochondria as well as in the presence of complex I inhibitor rotenone, which enhanced reactive oxygen species release. The phenomena revealed in this report are important for understanding mechanisms governing mitochondrial production of reactive oxygen species, in particular that related with uncoupling proteins. PMID:18687689

Selivanov, Vitaly A; Zeak, Jennifer A; Roca, Josep; Cascante, Marta; Trucco, Massimo; Votyakova, Tatyana V

2008-08-07

173

Peroxisomes and reactive oxygen species, a lasting challenge.  

PubMed

Oxidases generating and enzymes scavenging H2O2 predestine peroxisomes (PO) to a pivotal organelle in oxygen metabolism. Catalase, the classical marker enzyme of PO, exhibits both catalytic and peroxidatic activity. The latter is responsible for the staining with 3,3'-diamino-benzidine, which greatly facilitated the visualization of the organelle and promoted further studies on PO. D-Amino acid oxidase catalyzes with strict stereospecificity the oxidative deamination of D-amino acids. The oxidase is significantly more active in the kidney than in liver and more in periportal than pericentral rat hepatocytes. Peroxisomes in these tissues differ in their enzyme activity and protein concentration not only in adjacent cells but even within the same one. Moreover, the enzyme appears preferentially concentrated in the central region of the peroxisomal matrix compartment. Urate oxidase, a cuproprotein catalyzing the oxidation of urate to allantoin, is confined to the peroxisomal core, yet is lacking in human PO. Recent experiments revealed that cores in rat hepatocytes appear in close association with the peroxisomal membrane releasing H2O2 generated by urate oxidase to the surrounding cytoplasma. Xanthine oxidase is exclusively located to cores, oxidizes xanthine thereby generating H2O2 and O2(-) radicals. The latter are converted to O2 and H2O2 by CuZn superoxide dismutase, which has been shown recently to be a bona fide peroxisomal protein. PMID:19224237

Angermüller, Sabine; Islinger, Markus; Völkl, Alfred

2009-02-18

174

Roles of Reactive Oxygen and Nitrogen Species in Pain  

PubMed Central

Peroxynitrite (PN, ONOO?) and its reactive oxygen precursor superoxide (SO, O2·?), are critically important in the development of pain of several etiologies including in the development of pain associated with chronic use of opiates such as morphine (also known as opiate-induced hyperalgesia and antinociceptive tolerance). This is now an emerging field in which considerable progress has been made in terms of understanding the relative contribution of SO, PN, and nitroxidative stress in pain signaling at the molecular and biochemical levels. Aggressive research in this area is poised to provide the pharmacological basis for development of novel non-narcotic analgesics that are based upon the unique ability to selectively eliminate SO and/or PN. As we have a better understanding of the role of SO and PN in pathophysiological settings, targeting PN may be a better therapeutic strategy than targeting SO. This is due to the fact that unlike PN, which has no currently known beneficial role, SO may play a significant role in learning and memory [1]. Thus, the best approach may be to spare SO while directly targeting its downstream product, PN. Over the last 15 years, our team has spearheaded research concerning the roles of SO/PN in pain and these results are currently leading to the development of solid therapeutic strategies in this important area.

Salvemini, Daniela; Little, Joshua W.; Doyle, Timothy; Neumann, William L.

2011-01-01

175

Metabolic regulation and overproduction of primary metabolites.  

PubMed

Overproduction of microbial metabolites is related to developmental phases of microorganisms. Inducers, effectors, inhibitors and various signal molecules play a role in different types of overproduction. Biosynthesis of enzymes catalysing metabolic reactions in microbial cells is controlled by well-known positive and negative mechanisms, e.g. induction, nutritional regulation (carbon or nitrogen source regulation), feedback regulation, etc. The microbial production of primary metabolites contributes significantly to the quality of life. Fermentative production of these compounds is still an important goal of modern biotechnology. Through fermentation, microorganisms growing on inexpensive carbon and nitrogen sources produce valuable products such as amino acids, nucleotides, organic acids and vitamins which can be added to food to enhance its flavour, or increase its nutritive values. The contribution of microorganisms goes well beyond the food and health industries with the renewed interest in solvent fermentations. Microorganisms have the potential to provide many petroleum-derived products as well as the ethanol necessary for liquid fuel. Additional applications of primary metabolites lie in their impact as precursors of many pharmaceutical compounds. The roles of primary metabolites and the microbes which produce them will certainly increase in importance as time goes on. In the early years of fermentation processes, development of producing strains initially depended on classical strain breeding involving repeated random mutations, each followed by screening or selection. More recently, methods of molecular genetics have been used for the overproduction of primary metabolic products. The development of modern tools of molecular biology enabled more rational approaches for strain improvement. Techniques of transcriptome, proteome and metabolome analysis, as well as metabolic flux analysis. have recently been introduced in order to identify new and important target genes and to quantify metabolic activities necessary for further strain improvement. PMID:21261849

Sanchez, Sergio; Demain, Arnold L

2008-07-01

176

Proline does not quench singlet oxygen: evidence to reconsider its protective role in plants.  

PubMed

Plants are commonly subjected to several environmental stresses that lead to an overproduction of reactive oxygen species (ROS). As plants accumulate proline in response to stress conditions, some authors have proposed that proline could act as a non-enzymatic antioxidant against ROS. One type of ROS aimed to be quenched by proline is singlet oxygen ((1)O(2))-molecular oxygen in its lowest energy electronically excited state-constitutively generated in oxygenic, photosynthetic organisms. In this study we clearly prove that proline cannot quench (1)O(2) in aqueous buffer, giving rise to a rethinking about the antioxidant role of proline against (1)O(2). PMID:23384940

Signorelli, Santiago; Arellano, Juan Bautista; Melø, Thor Bernt; Borsani, Omar; Monza, Jorge

2013-01-17

177

Eluding the gravitino overproduction in inflaton decay  

NASA Astrophysics Data System (ADS)

It is known that gravitinos are non-thermally produced in inflaton decay processes, which excludes many inflation models for a wide range of the gravitino mass. We find that the constraints from the gravitino overproduction can be greatly relaxed if the supersymmetry breaking field is much lighter than the inflaton, and if the dynamical scale of the supersymmetry breaking is higher than the inflaton mass. In particular, we show that many inflation models then become consistent with the pure gravity mediation with O(100) TeV gravitino which naturally explains the recently observed Higgs boson mass of about 125 GeV.

Nakayama, Kazunori; Takahashi, Fuminobu; Yanagida, Tsutomu T.

2012-12-01

178

Anoxia-induced changes in reactive oxygen species and cyclic nucleotides in the painted turtle  

Microsoft Academic Search

The Western painted turtle survives months without oxygen. A key adaptation is a coordinated reduction of cellular ATP production\\u000a and utilization that may be signaled by changes in the concentrations of reactive oxygen species (ROS) and cyclic nucleotides\\u000a (cAMP and cGMP). Little is known about the involvement of cyclic nucleotides in the turtle’s metabolic arrest and ROS have\\u000a not been

Matthew Edward Pamenter; Michael David Richards; Leslie Thomas Buck

2007-01-01

179

Involvement of Reactive Oxygen and Nitrogen Species in the Pathogenesis of Acute Lung Injury  

Microsoft Academic Search

Reactive oxygen and nitrogen intermediates, produced by the interaction of NO with partially reduced oxygen species, affect\\u000a lung function and homeostasis in a variety of different ways. They act as signaling agents and play an essential role in pathogen\\u000a killing. On the other hand, they may contribute to tissue injury by upregulating genes responsible for the production of inflammatory\\u000a mediators

S. Matalon; I. Davis; J. Lang

180

Bcl2 Inhibition of Neural Death: Decreased Generation of Reactive Oxygen Species  

Microsoft Academic Search

The proto-oncogene bcl-2 inhibits apoptotic and necrotic neural cell death. Expression of Bcl-2 in the GT1-7 neural cell line prevented death as a result of glutathione depletion. Intracellular reactive oxygen species and lipid peroxides rose rapidly in control cells depleted of glutathione, whereas cells expressing Bcl-2 displayed a blunted increase and complete survival. Modulation of the increase in reactive oxygen

Darci J. Kane; Theodore A. Sarafian; Rein Anton; Hejin Hahn; Edith Butler Gralla; Joan Selverstone Valentine; Tonis Ord; Dale E. Bredesen

1993-01-01

181

Molecular Cell Biology: Are Reactive Oxygen Species Regulators of Leaf Senescence?  

Microsoft Academic Search

Senescence processes can influence many important agricultural traits; however, our knowledge concerning regulatory mechanisms\\u000a controlling senescence is still limited. Free radicals are thought to play an essential role in senescence, especially those\\u000a derived from oxygen. In addition to their deleterious functions, they might serve as signalling molecules. The critical balance\\u000a between production and scavenging of reactive oxygen species (ROS), which

Ulrike Zentgraf; Vera Hemleben

182

Studies of oxygen species in synthetic Todorokite-like manganese oxide octahedral molecular sieves  

SciTech Connect

Manganese oxide octahedral molecular sieves of 3 x 3 tunnel structure (OMS-1) doped with various cations possess high thermal stability and were studied by means of temperature-programmed desorption and reduction by H[sub 2] and CO. Different oxygen species can be discerned according to their peak positions in the temperature-programmed desorption and reduction and assigned to chemisorbed dioxygen, oxygen atoms bound to Mn[sup 2+], and those bound to Mn[sup 4+] ions in the framework. Differences in peak positions and availabilities of these species during TPD and TPR can be explained by creation of nascent Mn[sup 2+] ions during TPR. The effects of doping cations on the reactivity and availability of these oxygen species are demonstrated to be more pronounced in TPR in H[sub 2] or CO than in TPD. In some instances, the trends of changes in reactivity and availability of the oxygen species due to doping of Cu[sup 2+], Ni[sup 2+], Zn[sup 2+], and Mg[sup 2+] correlated with the changes in the heat of formation of oxides of these cations. Temperature-programmed reactions with methane show some reactivity of these doped OMS-1 materials. Pulse reactions with CO show higher reactivity of Cu-doped OM-1 than with butane. However, the recovery of Cu-doped OMS-1 by reoxidation with oxygen pulses seems rather incomplete at the same temperature. 27 refs., 9 figs.

Yin, Yuan-Gen; Xu, Wen-Qing; Shen, Yan-Fei; Suib, S.L. (Univ. of Connecticut, Storrs, CT (United States)); O'Young, C.L. (Texaco Research Center, New York, NY (United States))

1994-10-01

183

Extreme Oxatriquinanes: Structural Characterization of ?-Oxyoxonium Species with Extraordinarily Long Carbon-Oxygen Bonds.  

PubMed

The first stable ?-oxyoxonium species have been synthesized and characterized. Strong donation of nonbonding electrons on oxygen into the adjacent ?*(C-O(+)) orbital was predicted by modeling to result in unheard of carbon-oxygen bond lengths. The kinetic stability of the triquinane ring system provides a platform upon which to study these otherwise elusive species, which are evocative of intermediates on the acetalization reaction pathway. Crystallographic analysis of the ?-hydroxy and ?-methoxy oxatriquinane triflates reveals 1.658 and 1.619 Å C-O(+) bond lengths, respectively, the former of which is a new record for the C-O bond. PMID:23682676

Gunbas, Gorkem; Sheppard, William L; Fettinger, James C; Olmstead, Marilyn M; Mascal, Mark

2013-05-21

184

Cellular Response of Pea Plants to Cadmium Toxicity: Cross Talk between Reactive Oxygen Species, Nitric Oxide, and Calcium1[W][OA  

PubMed Central

Cadmium (Cd) toxicity has been widely studied in different plant species; however, the mechanism involved in its toxicity as well as the cell response against the metal have not been well established. In this work, using pea (Pisum sativum) plants, we studied the effect of Cd on antioxidants, reactive oxygen species (ROS), and nitric oxide (NO) metabolism of leaves using different cellular, molecular, and biochemical approaches. The growth of pea plants with 50 ?m CdCl2 affected differentially the expression of superoxide dismutase (SOD) isozymes at both transcriptional and posttranscriptional levels, giving rise to a SOD activity reduction. The copper/zinc-SOD down-regulation was apparently due to the calcium (Ca) deficiency induced by the heavy metal. In these circumstances, the overproduction of the ROS hydrogen peroxide and superoxide could be observed in vivo by confocal laser microscopy, mainly associated with vascular tissue, epidermis, and mesophyll cells, and the production of superoxide radicals was prevented by exogenous Ca. On the other hand, the NO synthase-dependent NO production was strongly depressed by Cd, and treatment with Ca prevented this effect. Under these conditions, the pathogen-related proteins PrP4A and chitinase and the heat shock protein 71.2, were up-regulated, probably to protect cells against damages induced by Cd. The regulation of these proteins could be mediated by jasmonic acid and ethylene, whose contents increased by Cd treatment. A model is proposed for the cellular response to long-term Cd exposure consisting of cross talk between Ca, ROS, and NO.

Rodriguez-Serrano, Maria; Romero-Puertas, Maria C.; Pazmino, Diana M.; Testillano, Pilar S.; Risueno, Maria C.; del Rio, Luis A.; Sandalio, Luisa M.

2009-01-01

185

c-Ets1 inhibits the interaction of NF-?B and CREB, and downregulates IL-1?-induced MUC5AC overproduction during airway inflammation  

PubMed Central

Mucin hypersecretion is frequently observed in many inflammatory diseases of the human respiratory tract. As mucin hypersecretion refers to uncontrolled mucin expression and secretion during inflammation, studies examining the negative control mechanisms of mucin hypersecretion are vital in developing novel therapeutic medications. We hypothesized that the c-Ets1 induced by interleukin (IL)-1? would decrease MUC5AC overproduction by inhibiting the interaction of NF-?B with cAMP response element-binding protein (CREB) in vivo. Stimulation with IL-1? caused the direct binding of NF-?B and CREB to the MUC5AC promoter, thus increasing MUC5AC gene expression. However, IL-1?-induced MUC5AC messenger RNA levels were surprizingly downregulated by c-Ets1 (located ?938 to ?930). Interestingly, c-Ets1 also suppressed IL-1?-induced MUC5AC gene expression in vitro and in vivo by disrupting the interaction of NF-?B with CREB on the MUC5AC promoter. In addition, c-Ets1 also inhibited significant morphologic changes and inflammatory cell infiltration after IL-1? exposure in mouse lungs infected with either wild-type or shRNA-c-Ets1. Moreover, reactive oxygen species produced by NOX4 increased c-Ets1 gene expression and MUC5AC gene expression in alveolar macrophages from bronchoalveolar lavage fluid. These results suggest a molecular paradigm for the establishment of a novel mechanism underlying the negative regulation of mucin overproduction, thus enhancing our understanding of airway inflammation.

Song, K S; Yoon, J-H; Kim, K S; Ahn, D W

2012-01-01

186

Cell death from antibiotics without the involvement of reactive oxygen species  

PubMed Central

Recent observations have suggested that classic antibiotics kill bacteria by stimulating the formation of reactive oxygen species. If true, this notion might guide new strategies to improve antibiotic efficacy. In this study the model was directly tested. Contrary to the hypothesis, antibiotic treatment did not accelerate the formation of hydrogen peroxide in Escherichia coli and did not elevate intracellular free iron, an essential reactant for the production of lethal damage. Lethality persisted in the absence of oxygen, and DNA repair mutants were not hypersensitive, undermining the idea that toxicity arose from oxidative DNA lesions. We conclude that these antibiotic exposures did not produce reactive oxygen species and that lethality more likely resulted from the direct inhibition of cell-wall assembly, protein synthesis, and DNA replication.

Liu, Yuanyuan; Imlay, James A.

2013-01-01

187

Semiconducting polymer nanoprobe for in?vivo imaging of reactive oxygen and nitrogen species.  

PubMed

Semiconducting polymer nanoparticles are used as a free-radical inert and light-harvesting nanoplatform for in?vivo molecular imaging of reactive oxygen and nitrogen species (RONS). This nanoprobe permits detection of RONS in the microenvironment of spontaneous bacterial infection (see picture; FRET=fluorescence resonance energy transfer). PMID:23943508

Pu, Kanyi; Shuhendler, Adam J; Rao, Jianghong

2013-08-13

188

Resveratrol scavenges reactive oxygen species and effects radical-induced cellular responses  

Microsoft Academic Search

Scavenging or quenching of the reactive oxygen species (ROS) involved in oxidative stress has been the subject of many recent studies. Resveratrol, found in various natural food products, has been linked to decreased coronary artery disease and preventing cancer development. The present study measured the effect of resveratrol on several different systems involving the hydroxyl, superoxide, metal\\/enzymatic-induced, and cellular generated

Stephen S Leonard; Chang Xia; Bin-Hua Jiang; Beth Stinefelt; Hillar Klandorf; Gabriel K Harris; Xianglin Shi

2003-01-01

189

Dual action of the active oxygen species during plant stress responses  

Microsoft Academic Search

Adaptation to environmental changes is crucial for plant growth and survival. However, the molecular and biochemical mechanisms of adaptation are still poorly understood and the signaling pathways involved remain elusive. Active oxygen species (AOS) have been proposed as a central component of plant adaptation to both biotic and abiotic stresses. Under such conditions, AOS may play two very different roles:

J. Dat; S. Vandenabeele; E. Vranova ´; M. Van Montagu; F. Van Breusegem

2000-01-01

190

The Role of Active Oxygen Species and Lipid Peroxidation in the Antitumor Effect of Hyperthermia  

Microsoft Academic Search

The role of active oxygen species and lipid peroxidation in the antitu- iiuir effect of hyperthermia was studied in an experimental rabbit model. VX2 tumors were transplanted Into rabbit hind legs, and the effect of hyperthermia on tumor growth was measured at 7 and 14 days after heating. As an index of lipid peroxidation, thiobarbituric acid-reactive substances in the tumor

Toshikazu Yoshikawa; Satoshi Kokura; Kenzo Tainaka; Kenji Itani; Hirokazu Oyamada; Toshiro Kaneko; Yuji Naito; Motoharu Kondo

1993-01-01

191

Vanadate-Induced Cell Growth Regulation and the Role of Reactive Oxygen Species  

Microsoft Academic Search

While vanadium compounds are known as potent toxicants as well as carcinogens, the mechanisms of their toxic and carcinogenic actions remain to be investigated. It is believed that an improper cell growth regulation leads to cancer development. The present study examines the effects of vanadate on cell cycle control and involvement of reactive oxygen species (ROS) in these vanadate-mediated responses

Zhuo Zhang; Chuanshu Huang; Jingxia Li; Stephen S. Leonard; Robert Lanciotti; Leon Butterworth; Xianglin Shi

2001-01-01

192

Protection of neuronal cells against reactive oxygen species by carnosine and related compounds  

Microsoft Academic Search

Carnosine and related compounds were compared in terms of their abilities to decrease the levels of reactive oxygen species (ROS) in suspensions of isolated neurons activated by N-methyl-d-aspartic acid (NMDA) using both stationary fluorescence measurements and flow cytometry. Carnosine was found to suppress the fluorescent signal induced by ROS production and decreased the proportion of highly fluorescent neurons, while histidine

Alexander Boldyrev; Elena Bulygina; Toomas Leinsoo; Irina Petrushanko; Shiori Tsubone; Hiroki Abe

2004-01-01

193

Fundamental roles of reactive oxygen species and protective mechanisms in the female reproductive system  

Microsoft Academic Search

Controlled oxidation, such as disulfide bond formation in sperm nuclei and during ovulation, plays a fundamental role in mammalian reproduction. Excess oxidation, however, causes oxidative stress, resulting in the dysfunction of the reproductive process. Antioxidation reactions that reduce the levels of reactive oxygen species are of prime importance in reproductive systems in maintaining the quality of gametes and support reproduction.

Junichi Fujii; Yoshihito Iuchi; Futoshi Okada

2005-01-01

194

Antioxidants and reactive oxygen species in follicular fluid of women undergoing IVF: relationship to outcome  

Microsoft Academic Search

BACKGROUND: The role of free radicals and reactive oxygen species (ROS) in female reproductive function is still unclear. The present study was designed to investigate their relationship with ovulation, fertilization and con- ception. METHODS: Follicular aspirates obtained from women undergoing IVF following controlled ovarian stimu- lation were evaluated using the ferric reducing antioxidant power (FRAP) assay for baseline total antioxidant

O. Oyawoye; A. Abdel Gadir; A. Garner; N. Constantinovici; C. Perrett; P. Hardiman

2003-01-01

195

Mitochondrial function and reactive oxygen species action in relation to boar motility.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Flow cytometric assays of viable boar sperm were developed to measure reactive oxygen species (ROS) formation (oxidization of hydroethidine to ethidium), membrane lipid peroxidation (oxidation of lipophilic probe C11-BODIPY581/591), and mitochondrial inner transmembrane potential (aggregation of mit...

196

Increased susceptibility to phenytoin teratogenicity: excessive generation of reactive oxygen species or impaired antioxidant defense?  

PubMed

Phenytoin is a human and animal teratogen. Accumulating evidence suggests that the teratogenicity is associated with a potential of phenytoin to cause embryonic cardiac arrhythmia and resultant generation of toxic reactive oxygen species via hypoxia-reoxygenation mechanisms. The A/J mouse is more susceptible to phenytoin teratogenicity than other mouse strains. The aim of this study was to investigate whether A/J mice have other antioxidant enzyme activities than C57BL/6J and CD-1 mice. Also, strain differences in phenytoin effects on embryonic heart rate and rhythm were determined. Another objective was to determine whether a spin trapping agent with capacity to capture reactive oxygen species alter the developmental toxicity of phenytoin. Treatment with this agent resulted in a marked decrease in phenytoin teratogenicity, which supports the idea that reactive oxygen species are important mediators for the teratogenic action of phenytoin. The A/J mice embryos were most susceptible to the adverse cardiac effects of phenytoin and had the highest activity of superoxide dismutase and glutathione peroxidase, while the activity of catalase was the same in embryos of the three different strains. The high activities of antioxidant enzymes in the A/J stain indicate that the sensitivity to develop malformations is caused by excessive arrhythmia-related generation of reactive oxygen species rather than impaired antioxidant defense. PMID:17040216

Azarbayjani, Faranak; Borg, L A Håkan; Danielsson, Bengt R

2006-10-01

197

[Reactive oxygen species and 3,4-dihydroxyphenylacetaldehyde in pathogenesis of Parkinson disease].  

PubMed

Reactive oxygen species, which plays a role in pathogenesis of many neurodegenerative diseases, seems to be important also in pathogenesis of the Parkinson's disease. Experiments performed recently, revealed in the cerebrum of patients suffering from this disease (induced by the oxidative stress) elevated levels of 3,4-dihydroxyphenylacetaldehyde (DOPAL)--a strong endogenous neurotoxin to dopamine neurons. PMID:22010445

Rybakowska, Iwona; Szreder, Grzegorz; Kaletha, Krystian; Barwina, Ma?gorzata; Waldman, Wojciech; Sein Anand, Jacek

2011-01-01

198

Effect of resveratrol, a natural polyphenolic compound, on reactive oxygen species and prostaglandin production  

Microsoft Academic Search

Resveratrol is a natural molecule with antioxidant action. Moreover, resveratrol is also considered to be a molecule with anti-inflammatory action, an effect attributed to suppression of prostaglandin (PG) biosynthesis. The aim of the present study was to investigate the effects of resveratrol, a polyphenol present in most red wines, on reactive oxygen species formation as well as on arachidonic acid

Javier Martinez; Juan J Moreno

2000-01-01

199

Detection of reactive oxygen species by flow cytometry after spinal cord injury  

Microsoft Academic Search

The monitoring of reactive oxygen species (ROS) levels in injured nervous tissue is critical for both studying the mechanism of secondary damage and evaluating the effectiveness of antioxidants. Flow cytometry is an excellent method to detect ROS in cultured cells and naturally suspended individual cells. However, its use in nervous tissue is limited due to the difficulties in obtaining single

Jian Luo; Nianyu Li; J. Paul Robinson; Riyi Shi

2002-01-01

200

Reactive Oxygen Species (ROS) level in seminal plasma of infertile men and healthy donors  

Microsoft Academic Search

Background: Reactive Oxygen Species (ROS) are a group of free radicals that in excessive amounts have negative influence on sperm quality and function. Objective: We compared ROS levels in seminal plasma of infertile men with this level in healthy donors. We also determined the ROS level in semen of infertile men according to the etiology of infertility, and also the

Mohammad Reza Moein; Vali Ollah Dehghani; Nasim Tabibnejad; Serajadin Vahidi

2007-01-01

201

Quality Control of Reactive Oxygen Species Measurement by Luminol-Dependent Chemiluminescence Assay  

Microsoft Academic Search

A total of 28 donor semen samples were used to eval- uate the characteristics of laboratory variability in measuring reactive oxygen species (ROS). The objectives of this study were to assess the interassay (same sample observed on different days by the same observers) variability; interdonor, intraobserver (replications of the same sample on the same day) variability; and interobserver (multiple observers

HIROSHI KOBAYASHI; ENRIQUE GIL-GUZMAN; AYMAN M. MAHRAN; RAKESH K. SHARMA; DAVID R. NELSON; ANTHONY J. THOMAS JR; ASHOK AGARWAL

202

Detection of mitochondria-derived reactive oxygen species production by the chemilumigenic probes lucigenin and luminol  

Microsoft Academic Search

Both lucigenin and luminol have widely been used as chemilumigenic probes for detecting reactive oxygen species (ROS) production by various cellular systems. Our laboratory has previously demonstrated that lucigenin localizes to the mitochondria of rat alveolar macrophages and that lucigenin-derived chemiluminescence (CL) appears to reflects superoxide (O??2) production by mitochondria in the unstimulated macrophages. In this study, we further examined

Yunbo Li; Hong Zhu; Michael A. Trush

1999-01-01

203

Involvement of Reactive Oxygen Species in the Preservation Injury to Cultured Liver Endothelial Cells  

Microsoft Academic Search

We have previously demonstrated an energy-dependent injury to cultured liver endothelial cells during cold incubation in University of Wisconsin (UW) solution. In the present study, we report experimental evidence for the involvement of reactive oxygen species in this injury: LDH release during 48 h of cold incubation in UW solution was decreased from 40–55% under aerobic conditions to less than

Ursula Rauen; Birgit Elling; Elke R Gizewski; Hans-Gert Korth; Reiner Sustmann; Herbert de Groot

1997-01-01

204

Generation of singlet oxygen and other radical species by quantum dot and carbon dot nanosensitizers  

Microsoft Academic Search

Medicinal applications of luminescent semiconductor quantum dots are of growing interest. In spite of the fact that their fabrication and imaging applications have been extensively investigated for the last decade, very little is documented on photodynamic action of quantum dots. In this study we demonstrate generation of singlet oxygen and other radical species upon exposure of quantum dots to blue

Roman Generalov; Ingeborg L. Christensen; Wei Chen; Ya-Ping Sun; Solveig Kristensen; Petras Juzenas

2009-01-01

205

Two Distinct Sources of Elicited Reactive Oxygen Species in Tobacco Epidermal Cells  

Microsoft Academic Search

Reactive oxygen species (ROS) play a prominent role in early and later stages of the plant pathogenesis response, pu- tatively acting as both cellular signaling molecules and direct antipathogen agents. A single-cell assay, based on the fluorescent probe dichlorofluorescein, was used to scrutinize the generation and movement of ROS in tobacco epider- mal tissue. ROS, generated within cells, quickly moved

Andrew C. Allan; Robert Fluhr

1997-01-01

206

Regulation of Late G1\\/S Phase Transition and APCCdh1 by Reactive Oxygen Species  

Microsoft Academic Search

Proliferating cells have a higher metabolic rate than quiescent cells. To investigate the role of metabolism in cell cycle progression, we examined cell size, mitochondrial mass, and reactive oxygen species (ROS) levels in highly synchronized cell populations progressing from early G1 to S phase. We found that ROS steadily increased, compared to cell size and mitochondrial mass, through the cell

Courtney G. Havens; Alan Ho; Naohisa Yoshioka; Steven F. Dowdy

2006-01-01

207

Release of elicitors from rice blast spores under the action of reactive oxygen species  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effects of reactive oxygen species (ROS) on secretion of hypothesized elicitors from spores of rice blast causal fungus Magnaporthe grisea were studied. For spore exposure to exogenous ROS, they were germinated for 5 h in 50 µM H2O2 followed by addition of catalase E.C. 1.11.1.6 (to decompose pe...

208

Role of redox potential and reactive oxygen species in stress signaling  

Microsoft Academic Search

Stress-activated signaling cascades are affected by altered redox potential. Key contributors to altered redox potential are reactive oxygen species (ROS) which are formed, in most cases, by exogenous genotoxic agents including irradiation, inflammatory cytokines and chemical carcinogens. ROS and altered redox potential can be considered as the primary intracellular changes which regulate protein kinases, thereby serving as an important cellular

Victor Adler; Zhimin Yin; Kenneth D Tew; Ze'ev Ronai

1999-01-01

209

Detection of reactive oxygen species in mainstream cigarette smoke by a fluorescent probe  

Microsoft Academic Search

A mass of reactive oxygen species(ROS) are produced in the process of smoking. Superfluous ROS can induce the oxidative stress in organism, which will cause irreversible damage to cells. Fluorescent probe is taken as a marker of oxidative stress in biology and has been applied to ROS detection in the field of biology and chemistry for high sensitivity, high simplicity

Li Liu; Shi-Jie Xu; Song-Zhan Li

2009-01-01

210

Reactive oxygen species uncouple external horizontal cells in the carp retina and glutathione couples them again  

Microsoft Academic Search

We have investigated the effect of free radicals on the electrical gap junctions between horizontal cells in the carp retina. In our previous study, l-buthionine sulfoximine, an inhibitor of glutathione synthesis, caused uncoupling of horizontal cells four days after injection. In the present study, we have used paraquat, a generator of exogenous reactive oxygen species, to investigate whether it was

Z. Y Zhou; K Sugawara; R Hashi; K Muramoto; K Mawatari; T Matsukawa; Z. W Liu; M Devadas; S Kato

2001-01-01

211

Anxiety-Induced Plasma Norepinephrine Augmentation Increases Reactive Oxygen Species Formation by Monocytes in Essential Hypertension  

Microsoft Academic Search

Background: An association between anxiety and depression and increased blood pressure (BP) and cardiovascular disease risk has not been firmly established. We examined the hypothesis that anxiety and depression lead to increased plasma catecholamines and to production of reactive oxygen species (ROS) by mononuclear cells (MNC) in hypertensive individuals. We also studied the role of BP in this effect.Methods: In

Kenichi Yasunari; Tokuzo Matsui; Kensaku Maeda; Munehiro Nakamura; Takanori Watanabe; Nobuo Kiriike

2006-01-01

212

Regulation of Gene Expression in the Nervous System by Reactive Oxygen and Nitrogen Species  

Microsoft Academic Search

Reactive oxygen and nitrogen species function as direct and indirect modulators of gene expression through their interactions with transcription factors and also key enzymes in receptor-activated signalling pathways. This regulatory role may become displaced under certain circumstances such as aging, autoimmune responses and viral infection, leading to the pathological outcome associated with inflammatory and degenerative diseases in the CNS.

Jean E. Merrill; Sean P. Murphy

1997-01-01

213

Involvement of reactive oxygen species in aflatoxin B 1-induced cell injury in cultured rat hepatocytes  

Microsoft Academic Search

The role of reactive oxygen species (ROS) in AFB1-induced cell injury was investigated using cultured rat hepatocytes. Malonaldehyde (MDA) generation and lactate dehydrogenase (LDH) release were determined as indices of lipid peroxidation and cell injury, respectively. Exposure to AFB1 for up to 72 h resulted in significantly elevated levels of LDH being released into the medium as well as the

Han-Ming Shen; Choon-Nam Ong; Chen-Yang Shi

1995-01-01

214

A review of the interaction among dietary antioxidants and reactive oxygen species  

Microsoft Academic Search

During normal cellular activities, various processes inside of cells produce reactive oxygen species (ROS). Some of the most common ROS are hydrogen peroxide (H2O2), superoxide ion (O2?), and hydroxide radical (OH?). These compounds, when present in a high enough concentration, can damage cellular proteins and lipids or form DNA adducts that may promote carcinogenic activity. The purpose of antioxidants in

Harold E. Seifried; Darrell E. Anderson; Evan I. Fisher; John A. Milner

2007-01-01

215

Mechanisms for the generation of reactive oxygen species in plant defence – a broad perspective  

Microsoft Academic Search

In response to attempted invasion by a pathogen, plants mount a broad range of defence responses, including the generation of reactive oxygen species (ROS). The most spectacular and one of the earliest observable aspects of this mechanism is the oxidative burst – a rapid and transient production of large amounts of ROS. This review is intended to provide a broad

G. P. Bolwell; P. Wojtaszek

1997-01-01

216

Induction of Apoptosis by Chemotherapeutic Drugs without Generation of Reactive Oxygen Species  

Microsoft Academic Search

Studies in a variety of cell types have suggested that cancer chemotherapy drugs induce tumor cell apoptosis in part by inducing formation of reactive oxygen species (ROS). Using human B lymphoma cells as the targets, we have found that apoptosis can be induced in the absence of any detectable oxidative stress. Apoptosis was induced with the chemotherapy drugs VP-16 and

Sema Sentürker; Richard Tschirret-Guth; Jason Morrow; Rod Levine; Emily Shacter

2002-01-01

217

Catecholamine-Induced Vascular Wall Growth Is Dependent on Generation of Reactive Oxygen Species  

Microsoft Academic Search

Adrenoceptor- dependent proliferation of vascular smooth muscle cells (VSMCs) is strongly augmented by vascular injury, and may contribute to intimal growth and lumen loss. Because reactive oxygen species (ROS) are increased by injury and have been implicated as second messengers in proliferation of VSMCs, we investigated the role of ROS in catecholamine-induced VSMC growth. Rat aortae were isolated 4 days

Tina Bleeke; Hua Zhang; Nageswara Madamanchi; Cam Patterson; James E. Faber

2010-01-01

218

Impact of iron sucrose therapy on leucocyte surface molecules and reactive oxygen species in haemodialysis patients  

Microsoft Academic Search

Background. It has been suggested that iron increases oxidative stress and that an excess of iron contributes to cardiovascular disease and infections in haemo- dialysis patients. In the present study, the effects of parenterally administered iron on leucocyte surface molecule expression and the production of reactive oxygen species (ROS) were evaluated. Methods. Ten chronic haemodialysis (HD) patients without iron overload

Galip Guz; Griet L. Glorieux; Rita De Smet; Marie-Anne F. Waterloos; Raymond C. Vanholder; Annemieke W. Dhondt

2006-01-01

219

Metallothionein in human atherosclerotic lesions: a scavenger mechanism for reactive oxygen species in the plaque?  

Microsoft Academic Search

Oxidative stress is important in the genesis of atherosclerotic lesions. The extracellular effects of reactive oxygen species (ROS), such as oxidative modification of lipoproteins and upregulation of matrix degrading enzymes, are considered crucial in this context. The effects of ROS are counteracted by antioxidant scavenging systems; metallothioneins (MTs) may serve as such. This study was designed to see whether MTs

Heike Göbel; Allard C. van der Wal; Peter Teeling; Chris M. van der Loos; Anton E. Becker

2000-01-01

220

Mitochondrial Reactive Oxygen Species Trigger Calcium Increases During Hypoxia in Pulmonary Arterial Myocytes  

Microsoft Academic Search

We hypothesized that mitochondria function as the O2 sensors underlying hypoxic pulmonary vasoconstriction by releasing reactive oxygen species (ROS) from complex III of the electron transport chain (ETC). We have previously found that antioxidants or inhibition of the proximal region of the ETC attenuates hypoxic pulmonary vasoconstriction in rat lungs and blocks hypoxia-induced contraction of isolated pulmonary arterial (PA) myocytes.

Gregory B. Waypa; Jeremy D. Marks; Mathew M. Mack; Chan Boriboun; Paul T. Mungai; Paul T. Schumacker

2009-01-01

221

Role of reactive oxygen species in regulating collagen metabolism in fibroblasts  

Microsoft Academic Search

Introduction. Reactive oxygen species (ROS) are traditionally viewed as detrimental to cells by means of causing oxidative damage. However, recent studies have shown that micromolar concentrations of oxidants actually help facilitate wound repair by inducing vascular endothelial growth factor (VEGF) in wound-related cells such as macrophages and keratinocytes. It is hypothesized that aged fibroblasts will have a lower basal cell

R. C. Piazza; D. D. Poliquit; L. J. Gould

2004-01-01

222

Cytotoxic effect of formaldehyde with free radicals via increment of cellular reactive oxygen species  

Microsoft Academic Search

It is well known that formaldehyde (HCHO) and reactive oxygen species (ROS), such as free radicals, are cytotoxic as well as potentially carcinogenic. Although the individual effects of these reactants on cells have been investigated, the cytotoxicity exerted by the coexistence of HCHO and reactive radicals is poorly understood. The present study using Jurkat cells demonstrated that the coexistence of

Yoshiro Saito; Keiko Nishio; Yasukazu Yoshida; Etsuo Niki

2005-01-01

223

Molecular events associated with reactive oxygen species and cell cycle progression in mammalian cells  

Microsoft Academic Search

Cell cycle progression is regulated by a wide variety of external factors, amongst them are growth factors and extracellular matrix factors. During the last decades evidence has been obtained that reactive oxygen species (ROS) may also play an important role in cell cycle progression. ROS may be generated by external and internal factors. In this overview we describe briefly the

Johannes Boonstra; Jan Andries Post

2004-01-01

224

Elevated Cytosolic Na+ Increases Mitochondrial Formation of Reactive Oxygen Species in Failing Cardiac Myocytes  

PubMed Central

Background —Oxidative stress is causally linked to the progression of heart failure, and mitochondria are critical sources of reactive oxygen species in failing myocardium. We previously observed that in heart failure, elevated cytosolic Na+ ([Na+]i) reduces mitochondrial Ca2+ ([Ca2+]m) by accelerating Ca2+ efflux via the mitochondrial Na+/Ca2+ exchanger. Because the regeneration of antioxidative enzymes requires NADPH, which is indirectly regenerated by the Krebs cycle, and Krebs cycle dehydrogenases are activated by [Ca2+]m, we speculated that in failing myocytes, elevated [Na+]i promotes oxidative stress. Methods and Results —We used a patch-clamp–based approach to simultaneously monitor cytosolic and mitochondrial Ca2+ and, alternatively, mitochondrial H2O2 together with NAD(P)H in guinea pig cardiac myocytes. Cells were depolarized in a voltage-clamp mode (3 Hz), and a transition of workload was induced by ?-adrenergic stimulation. During this transition, NAD(P)H initially oxidized but recovered when [Ca2+]m increased. The transient oxidation of NAD(P)H was closely associated with an increase in mitochondrial H2O2 formation. This reactive oxygen species formation was potentiated when mitochondrial Ca2+ uptake was blocked (by Ru360) or Ca2+ efflux was accelerated (by elevation of [Na+]i). In failing myocytes, H2O2 formation was increased, which was prevented by reducing mitochondrial Ca2+ efflux via the mitochondrial Na+/Ca2+ exchanger. Conclusions —Besides matching energy supply and demand, mitochondrial Ca2+ uptake critically regulates mitochondrial reactive oxygen species production. In heart failure, elevated [Na+]i promotes reactive oxygen species formation by reducing mitochondrial Ca2+ uptake. This novel mechanism, by which defects in ion homeostasis induce oxidative stress, represents a potential drug target to reduce reactive oxygen species production in the failing heart.

Kohlhaas, Michael; Liu, Ting; Knopp, Andreas; Zeller, Tanja; Ong, Mei Fang; Bohm, Michael; O'Rourke, Brian; Maack, Christoph

2010-01-01

225

Low oxygen tolerance of different life stages of temperate freshwater fish species.  

PubMed

Data on low dissolved oxygen (DO?) tolerance of freshwater fish species of north-western Europe were used to create species sensitivity distributions (SSD). Lowest observed effect concentrations (LOEC) and 100% lethal concentrations (LC???) data were collected from the scientific literature. Comparisons were made among life stages as well as between native and exotic species. In addition, lethal DO? concentrations were compared to oxygen concentrations corresponding to maximum tolerable water temperatures of the same species. Fish eggs and embryos were the least tolerant. Juveniles had a significantly lower mean LOEC than adults, but there was no difference in mean LC??? between the two groups. The difference in lethal oxygen concentrations between adults and juveniles was largest for three salmonids, although it remains uncertain if this was a result of smoltification. There were no significant differences between native and exotic species; however, data on exotics are limited. DO? concentrations converted from maximum tolerable water temperatures were 3·9 times higher than the measured lethal DO? concentrations, which may reflect changes in respiration rates (Q??) and may also relate to the simplicity of the model used. PMID:23808700

Elshout, P M F; Dionisio Pires, L M; Leuven, R S E W; Wendelaar Bonga, S E; Hendriks, A J

2013-07-01

226

In vivo electron spin resonance: An effective new tool for reactive oxygen species/reactive nitrogen species measurement.  

PubMed

Reactive oxygen species are regarded as important factors in the initiation and progression of many diseases. Therefore, measurement of redox status would be helpful in understanding the "Redox Navigation" of such diseases. Because electron spin resonance (ESR) shows good signal responses to nitroxyl radical and various redox-related species, such as oxygen radicals and antioxidants, the in vivo ESR/nitroxyl probe technique can provide useful information on real-time redox status in a living body. ESR spectrometers for in vivo measurements can be operated at lower frequencies (approximately 3.5 GHz, 1 GHz, 700 MHz, and 300 MHz) than usual (9-10 GHz). Several types of resonators were also designed to minimize the dielectric loss of electromagnetic waves caused by water in animal bodies. In vivo ESR spectroscopy and its imaging have been used to analyze radical generation, redox status, partial pressure of oxygen and other conditions in various diseases. In addition, ESR has been used to analyze injury models related to oxidative stresses, such as nitroxyl radicals. The application of in vivo ESR for diseases related to oxidative injuries currently being investigated and the accumulation of basic data for therapy is ongoing. Recent progress in the instrumentation for in vivo ESR spectroscopy and its application to the life sciences are reviewed, because measurement of redox status in vivo is considered necessary to understand the initiation and progression of diseases. PMID:20945126

Han, Jin Yi; Hong, Jin Tae; Oh, Ki-Wan

2010-10-09

227

Prooxidant action of rosmarinic acid: transition metal-dependent generation of reactive oxygen species.  

PubMed

Rosmarinic acid and its constituent caffeic acid produced reactive oxygen species in the presence of transition metals. Complex of rosmarinic acid or caffeic acid with iron inactivated aconitase the most sensitive enzyme to oxidative stress. The inactivation of aconitase was iron-dependent, and prevented by TEMPOL, a scavenger of reactive oxygen species, suggesting that the rosmarinic acid/iron-mediated generation of superoxide anion is responsible for the inactivation of aconitase. Direct spectrophotometric determination of hydrogen peroxide and superoxide anion confirmed the rosmarinic acid/iron-dependent production of reactive oxygen species. Treatment of DNA from plasmid pBR322 and calf thymus with rosmarinic acid plus copper caused strand scission and formed 8-hydroxy-2'-deoxyguanosine in DNA. Rosmarinic acid and caffeic acid showed a potent activity that reduces transition metals. These results suggest that transition metals reduced by rosmarinic acid can form superoxide radical by one electron reduction of oxygen molecule: superoxide radical in turn converts to hydrogen peroxide and hydroxyl radical causing the formation of DNA base adduct. Cytotoxicity of rosmarinic acid may be related to the prooxidant action resulting from metal-reducing activity. PMID:17267171

Murakami, Keiko; Haneda, Miyako; Qiao, Shanlou; Naruse, Makoto; Yoshino, Masataka

2006-12-22

228

Involvement of soluble sugars in reactive oxygen species balance and responses to oxidative stress in plants.  

PubMed

Soluble sugars, especially sucrose, glucose, and fructose, play an obviously central role in plant structure and metabolism at the cellular and whole-organism levels. They are involved in the responses to a number of stresses, and they act as nutrient and metabolite signalling molecules that activate specific or hormone-crosstalk transduction pathways, thus resulting in important modifications of gene expression and proteomic patterns. Various metabolic reactions and regulations directly link soluble sugars with the production rates of reactive oxygen species, such as mitochondrial respiration or photosynthesis regulation, and, conversely, with anti-oxidative processes, such as the oxidative pentose-phosphate pathway and carotenoid biosynthesis. Moreover, stress situations where soluble sugars are involved, such as chilling, herbicide injury, or pathogen attack, are related to important changes in reactive oxygen species balance. These converging or antagonistic relationships between soluble sugars, reactive oxygen species production, and anti-oxidant processes are generally confirmed by current transcriptome analyses, and suggest that sugar signalling and sugar-modulated gene expression are related to the control of oxidative stress. All these links place soluble carbohydrates in a pivotal role in the pro-oxidant and antioxidant balance, and must have constrained the selection of adaptive mechanisms involving soluble sugars and preventing de-regulation of reactive oxygen species production. Finally, in line with the specific role of sucrose in oxygenic photosynthetic organisms, this role of soluble sugars in oxidative stress regulation seems to entail differential effects of glucose and sucrose, which emphasizes the unresolved issue of characterizing sucrose-specific signalling pathways. PMID:16397003

Couée, Ivan; Sulmon, Cécile; Gouesbet, Gwenola; El Amrani, Abdelhak

2006-01-05

229

Photo-Irradiation of Proanthocyanidin as a New Disinfection Technique via Reactive Oxygen Species Formation  

PubMed Central

In the present study, the bactericidal effect of photo-irradiated proanthocyanidin was evaluated in relation to reactive oxygen species formation. Staphylococcus aureus suspended in proanthocyanidin aqueous solution was irradiated with light from a laser at 405 nm. The bactericidal effect of photo-irradiated proanthocyanidin depended on the concentration of proanthocyanidin, the laser irradiation time, and the laser output power. When proanthocyanidin was used at the concentration of 1 mg/mL, the laser irradiation of the bacterial suspension could kill the bacteria with a >5-log reduction of viable cell counts. By contrast, bactericidal effect was not observed when proanthocyanidin was not irradiated. In electron spin resonance analysis, reactive oxygen species, such as hydroxyl radicals, superoxide anion radicals, and hydrogen peroxide, were detected in the photo-irradiated proanthocyanidin aqueous solution. The yields of the reactive oxygen species also depended on the concentration of proanthocyanidin, the laser irradiation time, and the laser output power as is the case with the bactericidal assay. Thus, it is indicated that the bactericidal effect of photo-irradiated proanthocyanidin is exerted via the reactive oxygen species formation. The bactericidal effect as well as the yield of the oxygen radicals increased with the concentration of proanthocyanidin up to 4 mg/mL, and then decreased with the concentration. These findings suggest that the antioxidative activity of proanthocyanidin might prevail against the radical generation potency of photo-irradiated proanthocyanidin resulting in the decreased bactericidal effect when the concentration is over 4 mg/mL. The present study suggests that photo-irradiated proanthocyanidin whenever used in an optimal concentration range can be a new disinfection technique.

Nakamura, Keisuke; Shirato, Midori; Ikai, Hiroyo; Kanno, Taro; Sasaki, Keiichi; Kohno, Masahiro; Niwano, Yoshimi

2013-01-01

230

Photo-irradiation of proanthocyanidin as a new disinfection technique via reactive oxygen species formation.  

PubMed

In the present study, the bactericidal effect of photo-irradiated proanthocyanidin was evaluated in relation to reactive oxygen species formation. Staphylococcus aureus suspended in proanthocyanidin aqueous solution was irradiated with light from a laser at 405 nm. The bactericidal effect of photo-irradiated proanthocyanidin depended on the concentration of proanthocyanidin, the laser irradiation time, and the laser output power. When proanthocyanidin was used at the concentration of 1 mg/mL, the laser irradiation of the bacterial suspension could kill the bacteria with a >5-log reduction of viable cell counts. By contrast, bactericidal effect was not observed when proanthocyanidin was not irradiated. In electron spin resonance analysis, reactive oxygen species, such as hydroxyl radicals, superoxide anion radicals, and hydrogen peroxide, were detected in the photo-irradiated proanthocyanidin aqueous solution. The yields of the reactive oxygen species also depended on the concentration of proanthocyanidin, the laser irradiation time, and the laser output power as is the case with the bactericidal assay. Thus, it is indicated that the bactericidal effect of photo-irradiated proanthocyanidin is exerted via the reactive oxygen species formation. The bactericidal effect as well as the yield of the oxygen radicals increased with the concentration of proanthocyanidin up to 4 mg/mL, and then decreased with the concentration. These findings suggest that the antioxidative activity of proanthocyanidin might prevail against the radical generation potency of photo-irradiated proanthocyanidin resulting in the decreased bactericidal effect when the concentration is over 4 mg/mL. The present study suggests that photo-irradiated proanthocyanidin whenever used in an optimal concentration range can be a new disinfection technique. PMID:23527299

Nakamura, Keisuke; Shirato, Midori; Ikai, Hiroyo; Kanno, Taro; Sasaki, Keiichi; Kohno, Masahiro; Niwano, Yoshimi

2013-03-20

231

Oxidases and reactive oxygen species during hematopoiesis: a focus on megakaryocytes  

PubMed Central

Reactive oxygen species (ROS), generated as a result of various reactions, control an array of cellular processes. The role of ROS during megakaryocyte (MK) development has been a subject of interest and research. The bone marrow niche is the major site of MK differentiation and maturation. In this environment, a gradient of oxygen tension, from normoxia to hypoxia results in different levels of ROS, impacting cellular physiology. This article provides an overview of major sources of ROS, their implication in different signaling pathways, and their effect on cellular physiology, with a focus on megakaryopoiesis. The importance of ROS-generating oxidases in MK biology and pathology, including myelofibrosis, is also described.

Eliades, Alexia; Matsuura, Shinobu; Ravid, Katya

2012-01-01

232

Responses of seven species of native freshwater fish and a shrimp to low levels of dissolved oxygen  

Microsoft Academic Search

The tolerances of seven New Zealand freshwater fish species and one species of shrimp to low levels of dissolved oxygen were determined in the laboratory by holding fish at dissolved oxygen levels of 1, 3, or 5 mg litre for 48 h at 15°C. Juvenile rainbow trout (Oncorhynchus mykiss) were also tested for comparison. All of the banded kokopu whitebait

Tracie L. Dean; Jody Richardson

1999-01-01

233

Probing oxidative stress: Small molecule fluorescent sensors of metal ions, reactive oxygen species, and thiols  

PubMed Central

Oxidative stress is a common feature shared by many diseases, including neurodegenerative diseases. Factors that contribute to cellular oxidative stress include elevated levels of reactive oxygen species, diminished availability of detoxifying thiols, and the misregulation of metal ions (both redox-active iron and copper as well as non-redox active calcium and zinc). Deciphering how each of these components interacts to contribute to oxidative stress presents an interesting challenge. Fluorescent sensors can be powerful tools for detecting specific analytes within a complicated cellular environment. Reviewed here are several classes of small molecule fluorescent sensors designed to detect several molecular participants of oxidative stress. We focus our review on describing the design, function and application of probes to detect metal cations, reactive oxygen species, and intracellular thiol-containing compounds. In addition, we highlight the intricacies and complications that are often faced in sensor design and implementation.

Hyman, Lynne M.; Franz, Katherine J.

2013-01-01

234

Small-molecule screen identifies reactive oxygen species as key regulators of neutrophil chemotaxis  

PubMed Central

Neutrophil chemotaxis plays an essential role in innate immunity, but the underlying cellular mechanism is still not fully characterized. Here, using a small-molecule functional screening, we identified NADPH oxidase–dependent reactive oxygen species as key regulators of neutrophil chemotactic migration. Neutrophils with pharmacologically inhibited oxidase, or isolated from chronic granulomatous disease (CGD) patients and mice, formed more frequent multiple pseudopodia and lost their directionality as they migrated up a chemoattractant concentration gradient. Knocking down NADPH oxidase in differentiated neutrophil-like HL60 cells also led to defective chemotaxis. Consistent with the in vitro results, adoptively transferred CGD murine neutrophils showed impaired in vivo recruitment to sites of inflammation. Together, these results present a physiological role for reactive oxygen species in regulating neutrophil functions and shed light on the pathogenesis of CGD.

Hattori, Hidenori; Subramanian, Kulandayan K.; Sakai, Jiro; Jia, Yonghui; Li, Yitang; Porter, Timothy F.; Loison, Fabien; Sarraj, Bara; Kasorn, Anongnard; Jo, Hakryul; Blanchard, Catlyn; Zirkle, Dorothy; McDonald, Douglas; Pai, Sung-Yun; Serhan, Charles N.; Luo, Hongbo R.

2010-01-01

235

Stabilization of thylakoid membranes in isoprene-emitting plants reduces formation of reactive oxygen species  

PubMed Central

Isoprene is emitted by a significant fraction of the world's vegetation. Isoprene makes leaves more thermotolerant, yet we do not fully understand how. We have recently shown that isoprene stabilizes thylakoid membranes under heat stress. Here we show that heat-stressed, isoprene-emitting transgenic Arabidopsis plants also produce a lower pool of reactive oxygen and reactive nitrogen species, and that this was especially due to a lower accumulation of H2O2 in isoprene emitting plants. It remains difficult to disentangle whether in heat stressed plants isoprene also directly reacts with and quenches reactive oxygen species (ROS), or reduces ROS formation by stabilizing thylakoids. We present considerations that make the latter a more likely mechanism, under our experimental circumstances.     

Velikova, Violeta; Sharkey, Thomas D.; Loreto, Francesco

2012-01-01

236

Prooxidant action of knipholone anthrone: copper dependent reactive oxygen species generation and DNA damage.  

PubMed

Knipholone (KP) and knipholone anthrone (KA) are natural 4-phenylanthraquinone structural analogues with established differential biological activities including in vitro antioxidant and cytotoxic properties. By using DNA damage as an experimental model, the comparative Cu(II)-dependent prooxidant action of these two compounds were studied. In the presence of Cu(II) ions, the antioxidant KA (3.1-200 microM) but not KP (6-384 microM) caused a concentration-dependent pBR322 plasmid DNA strand scission. The DNA damage induced by KA could be abolished by reactive oxygen species scavengers, glutathione and catalase as well as EDTA and a specific Cu(I) chelator bathocuproine disulfonic acid. In addition to Cu(II) chelating activity, KA readily reduces Cu(II) to Cu(I). Copper-dependent generation of reactive oxygen species and the subsequent macromolecular damage may be involved in the antimicrobial and cytotoxic activity of KA. PMID:19345716

Habtemariam, S; Dagne, E

2009-04-05

237

The role of reactive oxygen and nitrogen species in cellular iron metabolism.  

PubMed

The catalytic role of iron in the Haber-Weiss chemistry, which results in propagation of damaging reactive oxygen species (ROS), is well established. In this review, we attempt to summarize the recent evidence showing the reverse: That reactive oxygen and nitrogen species can significantly affect iron metabolism. Their interaction with iron-regulatory proteins (IRPs) seems to be one of the essential mechanisms of influencing iron homeostasis. Iron depletion is known to provoke normal iron uptake via IRPs, superoxide and hydrogen peroxide are supposed to cause unnecessary iron uptake by similar mechanism. Furthermore, ROS are able to release iron from iron-containing molecules. On the contrary, nitric oxide (NO) appears to be involved in cellular defense against the iron-mediated ROS generation probably mainly by inducing iron removal from cells. In addition, NO may attenuate the effect of superoxide by mutual reaction, although the reaction product-peroxynitrite-is capable to produce highly reactive hydroxyl radicals. PMID:16484042

Mladenka, Premysl; Sim?nek, Tomás; Hübl, Mojmír; Hrdina, Radomír

2006-03-01

238

The role of reactive oxygen species on Plasmodium melanotic encapsulation in Anopheles gambiae  

PubMed Central

Malaria transmission depends on the competence of some Anopheles mosquitoes to sustain Plasmodium development (susceptibility). A genetically selected refractory strain of Anopheles gambiae blocks Plasmodium development, melanizing, and encapsulating the parasite in a reaction that begins with tyrosine oxidation, and involves three quantitative trait loci. Morphological and microarray mRNA expression analysis suggest that the refractory and susceptible strains have broad physiological differences, which are related to the production and detoxification of reactive oxygen species. Physiological studies corroborate that the refractory strain is in a chronic state of oxidative stress, which is exacerbated by blood feeding, resulting in increased steady-state levels of reactive oxygen species, which favor melanization of parasites as well as Sephadex beads.

Kumar, Sanjeev; Christophides, George K.; Cantera, Rafael; Charles, Bradley; Han, Yeon Soo; Meister, Stephan; Dimopoulos, George; Kafatos, Fotis C.; Barillas-Mury, Carolina

2003-01-01

239

Determination and detection of reactive oxygen species (ROS), lipid peroxidation, and electrolyte leakage in plants.  

PubMed

Reactive oxygen species or intermediates are formed by the incomplete reduction of oxygen. Organisms living in aerobic environment generate various kinds of reactive oxygen species (ROS) molecules, such as superoxide (*O(2)(-)), hydrogen peroxide (H(2)O(2)), hydroxyl radical (OH(-)), singlet oxygen, and lipid hydroperoxides. ROS are highly reactive molecules and are extremely unstable, so detection of ROS relies on measuring the end products that are formed when they react with particular substances. The end products can be measured by changes in their fluorescence, color, or luminescence. ROS causes lipid peroxidation wherein the lipids in the cell membranes are damaged. Lipid peroxidation is usually quantified using a colorimetric assay. When ROS concentrations reach a certain threshold, it activates a programmed cell death response in the cells. This is quantified by measuring the amount of ion leakage. ROS such as superoxide and hydrogen peroxide have been detected traditionally by staining techniques. Superoxide anion is detected with nitroblue tetrazolium (NBT) and hydrogen peroxide by Diaminobenzidine tetrahydrochloride (DAB) staining. In this chapter, methods for determining total ROS and lipid peroxidation assay, histochemical staining techniques for superoxide and H(2)O(2) molecules are described. PMID:20387054

Jambunathan, Niranjani

2010-01-01

240

Impact of copper on reactive oxygen species, lipid peroxidation and antioxidants in Lemna minor  

Microsoft Academic Search

Lemna minor L. treated with 20, 50, or 100 µM CuSO4 accumulated Cu and reactive oxygen species (hydrogen peroxide and superoxide radical) in frond and root cells. The time-course\\u000a analysis of lipid peroxidation showed high increment in malondialdehyde production only after 12 and 48 h of Cu treatment.\\u000a Guaiacol peroxidase and superoxide dismutase activities decreased after 48 h while glutathione

S. K. Panda

2008-01-01

241

Reactive Oxygen Species Mediate Endothelium-Dependent Relaxations in Tetrahydrobiopterin-Deficient Mice  

Microsoft Academic Search

R)-5,6,7,8-Tetrahydro-biopterin (H 4B) is essential for the catalytic activity of all NO synthases. The hyperphenylalaninemic mouse mutant (hph-1) displays 90% deficiency of the GTP cyclohydrolase I, the rate-limiting enzyme in H4B synthesis. A relative shortage of H4B may shift the balance between endothelial NO synthase (eNOS)-catalyzed generation of NO and reactive oxygen species. Therefore, the hph-1 mouse represents a unique

Francesco Cosentino; Jane E. Barker; Michael P. Brand; Simon J. Heales; Ernst R. Werner; John R. Tippins; Nick West; Keith M. Channon; Massimo Volpe; Thomas F. Lüscher

2001-01-01

242

Role of reactive oxygen species and MAPKs in vanadate-induced G 2\\/M phase arrest  

Microsoft Academic Search

Cell growth arrest is an important mechanism in maintaining genomic stability and integrity in response to environmental stress. Using the human lung alveolar epithelial cancer cell line A549, we investigated the role of reactive oxygen species (ROS), extracellular signal-regulated protein kinase (ERK), and p38 protein kinase in vanadate-induced cell growth arrest. Exposure of cells to vanadate led to cell growth

Zhuo Zhang; Stephen S Leonard; Chuanshu Huang; Val Vallyathan; Vince Castranova; Xianglin Shi

2003-01-01

243

1?,25-Dihydroxyvitamin D3 Modulation of Adipocyte Reactive Oxygen Species Production  

Microsoft Academic Search

Objective: We have previously shown 1?,25-dihydroxyvitamin D3 [1?,25-(OH)2D3] to inhibit mitochondrial uncoupling protein 2 (UCP2) expression in adipocytes and that in vivo suppression of calcitriol levels with calcium-rich diets increases UCP2 expression. Because UCP2 plays a significant role in the clearance of reactive oxygen species (ROS), we studied the effect of calcitriol on ROS production and ROS-induced adipocyte proliferation.Research Methods

Xiaocun Sun; Michael B. Zemel

2007-01-01

244

Effect of apoptosis and reactive oxygen species productionin human granulosa cells on oocyte fertilizationand blastocyst development  

Microsoft Academic Search

Purpose: The aim was to establish the impact of human granulosa cell apoptosis and reactive oxygen species (ROS) production on fertilization\\u000a competence of the oocyte, embryo developmental stage and implantation rate.\\u000a \\u000a \\u000a Methods: Thirty women undergoing IVF-ET for tubal factor infertility were included; GnRH antagonists and gonadotrophins were used\\u000a for ovarian stimulation. Granulosa cells were isolated from each aspirated follicle using

Nina Jan?ar; Andreja N. Kopitar; Alojz Ihan; Irma Virant Klun; Eda Vrta?nik Bokal

2007-01-01

245

Effect of Calcium on Reactive Oxygen Species in Isolated Rat Cardiomyocytes During Hypoxia and Reoxygenation  

Microsoft Academic Search

It has been suggested that calcium (Ca2+) overload and oxidative stress damage the myocardium during ischemia and reperfusion. We investigated the possible effect of varying extracellular Ca2+and total cell Ca2+on reactive oxygen species (ROS) levels in resting adult rat cardiomyocytes. Cardiomyocytes were isolated by trypsin\\/collagenase digestion and exposed to 1 h of hypoxia (H) (95% N2\\/5% CO2, no glucose) and

Mohammad Nouri Sharikabad; Else M Hagelin; Inger A Hagberg; Torstein Lyberg; Odd Brørs

2000-01-01

246

Role of reactive oxygen species and antioxidants on pathophysiology of male reproduction  

Microsoft Academic Search

The excessive generation of reactive oxygen species (ROS) by abnormal spermatozoa and contaminating leukocytes has been defined\\u000a as one of the few etiologies for male infertility. Administration of antioxidants in patients with ‘male factor’ infertility\\u000a has begun to attract considerable interest. The main difficulty of such an approach is our incomplete understanding of the\\u000a role of free radicals in normal

M Maneesh; H Jayalekshmi

2006-01-01

247

The role of Nrf2 in increased reactive oxygen species and DNA damage in prostate tumorigenesis  

Microsoft Academic Search

The impact of oxidative stress in human cancer has been extensively studied. It is accepted that elevated reactive oxygen species (ROS) promote mutagenic DNA damage. Even with an extensive armament of cellular antioxidants and detoxification enzymes, alterations to DNA occur that initiate cellular transformation. Erythroid 2p45 (NF- E2)-related factor 2 (Nrf2) is a basic-region leucine zipper transcription factor that mediates

DA Frohlich; MT McCabe; RS Arnold

2008-01-01

248

Differential production of reactive oxygen species by subsets of human spermatozoa at different stages of maturation  

Microsoft Academic Search

BACKGROUND: Reactive oxygen species (ROS)-mediated damage to human spermatozoa has been implicated in the pathogenesis of male infertility. Although ROS production by human spermatozoa has been extensively studied, the cell-to-cell variation in ROS production by spermatozoa at different stages of maturation has never been investigated. METHODS: In this study, we determined ROS production by subsets of human spermatozoa at different

E. Gil-Guzman; M. Ollero; M. C. Lopez; R. K. Sharma; J. G. Alvarez; A. J. Thomas; A. Agarwal

2001-01-01

249

Carnosine protects against excitotoxic cell death independently of effects on reactive oxygen species  

Microsoft Academic Search

The role of carnosine, N-acetylcarnosine and homocarnosine as scavengers of reactive oxygen species and protectors against neuronal cell death secondary to excitotoxic concentrations of kainate and N-methyl-d-aspartate was studied using acutely dissociated cerebellar granule cell neurons and flow cytometry. We find that carnosine, N-acetylcarnosine and homocarnosine at physiological concentrations are all potent in suppressing fluorescence of 2?,7?-dichlorofluorescein, which reacts with

A. Boldyrev; R. Song; D. Lawrence; D. O. Carpenter

1999-01-01

250

Protective systems against active oxygen species in spinach: response to cold acclimation in excess light  

Microsoft Academic Search

Spinach (Spinacia oleracea L.) plants were acclimated to 1° C or maintained at 18° C under the same light regime (260–300 µmol photons·m-2·s-1). The cold acclimation led to several metabolic and biochemical changes that apparently include improved protection of the photosynthetic apparatus against active oxygen species. In particular, cold-acclimated leaves exhibited a considerably higher ascorbate content and significantly increased activities

Susanne Schöner; G. Heinrich Krause

1990-01-01

251

Effects of reactive oxygen species on ?-tocopherol production in mitochondria and chloroplasts of Euglena gracilis  

Microsoft Academic Search

The effects of reactive oxygen species (ROS) on ?-tocopherol production in mitochondria and chloroplasts of Euglena gracilis were investigated. Addition of an organic carbon source to the medium resulted in increased mitochondrial activity, intracellular\\u000a O2\\u000a - concentration and ?-tocopherol productivity in E. gracilis W14ZUL (a chloroplast deficient mutant). ?-Tocopherol productivity of the wild-type strain (with both mitochondria and chloroplast)\\u000a was

Tomoya Fujita; James C. Ogbonna; Hideo Tanaka; Hideki Aoyagi

2009-01-01

252

The catalytically active copper-amyloid-Beta state: coordination site responsible for reactive oxygen species production.  

PubMed

Copper-amyloid-? ROS production: Copper ions (red sphere, see picture) have been found to accumulate in amyloid-? plaques and play a role in the generation of reactive oxygen species (ROS) within this context. Mass spectrometry studies were able to detail the sites of oxidation damage and shed new light on the mechanism of ROS production, important for the understanding of the pathogenicity of amyloid-? peptides. PMID:24038998

Cassagnes, Laure-Estelle; Hervé, Vincent; Nepveu, Françoise; Hureau, Christelle; Faller, Peter; Collin, Fabrice

2013-09-03

253

Antioxidant Activity of Hizikia fusiformis on Reactive Oxygen Species Scavenging and Lipid Peroxidation Inhibition  

Microsoft Academic Search

Water and organic extracts (diethyl ether, chloroform, ethyl acetate, acetone, ethanol and methanol) obtained from Hizikia fusiformis were screened on reactive oxygen species (ROS) scavenging assays (1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion, hydrogen peroxide and hydroxyl radical) and lipid peroxidation (inhibition of linoleic acid oxidation) inhibitory assays. Water, methanol and ethanol extracts showed significant ROS radical scavenging activities. Water extracts showed high

Nalin Siriwardhana; K.-W. Lee; Y.-J. Jeon; S.-H. Kim; J.-W. Haw

2003-01-01

254

Survival Signaling by CRAF: Mitochondrial Reactive Oxygen Species and Ca2+ Are Critical Targets  

Microsoft Academic Search

Survival signaling by RAF occurs through largely unknown mechanisms. Here we provide evidence for the first time that RAF controls cell survival by maintaining permissive levels of mitochondrial reactive oxygen species (ROS) and Ca2. Interleukin-3 (IL-3) withdrawal from 32D cells resulted in ROS production, which was suppressed by activated C-RAF. Oncogenic C-RAF decreased the percentage of apoptotic cells following treatment

Andrey V. Kuznetsov; Julija Smigelskaite; Christine Doblander; Manickam Janakiraman; Martin Hermann; Martin Wurm; Stefan F. Scheidl; Robert Sucher; Andrea Deutschmann; Jakob Troppmair

2008-01-01

255

Sunscreen enhancement of UV-induced reactive oxygen species in the skin  

Microsoft Academic Search

The number of UV-induced (20 mJ cm?2) reactive oxygen species (ROS) generated in nucleated epidermis is dependent upon the length of time the UV filter octocrylene, octylmethoxycinnamate, or benzophenone-3 remains on the skin surface. Two-photon fluorescence images acquired immediately after application of each formulation (2 mg cm?2) to the skin surface show that the number of ROS produced is dramatically reduced relative

Kerry M. Hanson; Enrico Gratton; Christopher J. Bardeen

2006-01-01

256

Increased Adhesion Molecules Expression and Production of Reactive Oxygen Species in Leukocytes of Sleep Apnea Patients  

Microsoft Academic Search

Obstructive sleep apnea (OSA) is associated with increased cardio- vascular morbidity and mortality. Free radicals and adhesion mole- cules were implicated in the pathogenesis of atherosclerosis lead- ing to cardiovascular disorders. Therefore, we investigated the link between CD15, CD11c, CD11b, and CD64 expression on leukocytes and their ability to generate reactive oxygen species (ROS) in pa- tients with OSA and

LARISSA DYUGOVSKAYA; PERETZ LAVIE; LENA LAVIE

257

Reactive Oxygen Species and Induction of Lignin Peroxidase in Phanerochaete chrysosporium  

Microsoft Academic Search

We studied oxidative stress in lignin peroxidase (LIP)-producing cultures (cultures flushed with pure O2 )o f Phanerochaete chrysosporium by comparing levels of reactive oxygen species (ROS), cumulative oxidative damage, and antioxidant enzymes with those found in non-LIP-producing cultures (cultures grown with free exchange of atmospheric air (control cultures)). A significant increase in the intracellular peroxide concen- tration and the degree

Paula A. Belinky; Nufar Flikshtein; Sergey Lechenko; Shimon Gepstein; Carlos G. Dosoretz

2003-01-01

258

Reactive Oxygen Species Regulate Swelling-induced Taurine Efflux in NIH3T3 Mouse Fibroblasts  

Microsoft Academic Search

NIH3T3 mouse fibroblasts generate reactive oxygen species (ROS) and release taurine following exposure to hypotonic medium and to isotonic medium containing the lipase activator melittin. The swelling-induced taurine release is potentiated by H2O2, the calmodulin antagonist W7, and ATP, but inhibited by the antioxidant butulated hydroxytoluene (BHT), the NAD(P)H oxidase inhibitor diphenylene iodonium (DI), and the iPLA2 inhibitor bromoenol lactone

I. H. Lambert

2003-01-01

259

Role of reactive oxygen species and phosphatidylinositol 3-kinase in cardiomyocyte differentiation of embryonic stem cells  

Microsoft Academic Search

Cardiotypic development in embryonic stem cell-derived embryoid bodies may be regulated by reactive oxygen species (ROS). ROS were generated by a NADPH oxidase-like enzyme which was transiently expressed during the time course of embryoid body development. Incubation with either H2O2 or menadione enhanced cardiomyogenesis, whereas the radical scavengers trolox, pyrrolidinedithiocarbamate and N-acetylcysteine exerted inhibitory effects. The phosphatidylinositol 3-kinase (PI-3-kinase) inhibitors

Heinrich Sauer; Gohar Rahimi; Jürgen Hescheler; Maria Wartenberg

2000-01-01

260

Anthrax Edema Toxin Inhibits Nox1-Mediated Formation of Reactive Oxygen Species by Colon Epithelial Cells  

Microsoft Academic Search

One major route of intoxication by Bacillus anthracis (anthrax) spores is via their ingestion and subsequent uptake by the intestinal epithelium. Anthrax edema toxin (ETx) is an adenylate cyclase that causes persistent elevation of cAMP in intoxicated cells. NADPH oxidase enzymes (Nox1–Nox5, Duox1 and 2) generate reactive oxygen species (ROS) as components of the host innate immune response to bacteria,

Jun-Sub Kim; Gary M. Bokoch

2009-01-01

261

Metabolism of reactive oxygen species in cotton cytoplasmic male sterility and its restoration  

Microsoft Academic Search

To elucidate reactive oxygen species (ROS) metabolism of cotton cytoplasmic male sterility and the effects of restorer gene\\u000a on the metabolism of ROS, the metabolism changes in the production and scavenging of ROS and gene expression related to ROS-scavenging\\u000a enzymes were investigated in the anther mitochondria of CMS line, maintainer line and hybrid F1. During the abortion preliminary stage (sporogenous

Peidong Jiang; Xiaoquan Zhang; Yunguo Zhu; Wei Zhu; Haiyan Xie; Xuede Wang

2007-01-01

262

The absence of reactive oxygen species production protects mice against bleomycin-induced pulmonary fibrosis  

Microsoft Academic Search

BACKGROUND: Reactive oxygen species and tissue remodeling regulators, such as metalloproteinases (MMPs) and their inhibitors (TIMPs), are thought to be involved in the development of pulmonary fibrosis. We investigated these factors in the fibrotic response to bleomycin of p47phox -\\/- (KO) mice, deficient for ROS production through the NADPH-oxidase pathway. METHODS: Mice are administered by intranasal instillation of 0.1 mg

Boris Manoury; Soazig Nenan; Olivier Leclerc; Isabelle Guenon; Elisabeth Boichot; Jean-Michel Planquois; Claude P Bertrand; Vincent Lagente

2005-01-01

263

Reactive oxygen species-induced DNA damage and its modification: A chemical investigation  

Microsoft Academic Search

The main purpose of this study was to determine whether well-known reactive oxygen species (ROS)-generating agents can induce DNA damage in a simple chemical system with or without Fenton reaction components (iron and reducing agents), and to explore whether antioxidants which normally exist in the cellular environment can modify such damage, i.e. to determine chemical reactions of relevance to biological

Tian-Wei Yu; Diana Anderson

1997-01-01

264

Nitric oxide counteracts cytotoxic processes mediated by reactive oxygen species in plant tissues  

Microsoft Academic Search

.   Many environmental conditions subject plants to oxidative stress, in which reactive oxygen species (ROS) are overproduced.\\u000a These ROS act as transduction signals in plant defense responses, but also cause effects that result in cellular damage. Since\\u000a nitric oxide (NO) is a bioactive molecule able to scavenge ROS, we analyzed its effect on some cytotoxic processes produced\\u000a by ROS in

María Verónica Beligni; Lorenzo Lamattina

1999-01-01

265

Roles of the reactive oxygen species-generating peroxidase reactions in plant defense and growth induction  

Microsoft Academic Search

Extracellularly secreted plant peroxidases (POXs) are considered to catalyze the generation of reactive oxygen species (ROS) coupled to oxidation of plant hormone indole-3-acetic acid (IAA) and defense-related compounds salicylic acid (SA), aromatic monoamines (AMAs) and chitooligosaccharides (COSs). This review article consists of two parts, which describe H2O2-dependent and H2O2-independent mechanisms for ROS generation, respectively. Recent studies have shown that plant

T. Kawano

2003-01-01

266

Bufalin Induces Reactive Oxygen Species Dependent Bax Translocation and Apoptosis in ASTC-a-1 Cells  

Microsoft Academic Search

Bufalin has been shown to induce cancer cell death through apoptotic pathways. However, the molecular mechanisms are not well understood. In this study, we used the confocal fluorescence microscopy (CFM) to monitor the spatio-temporal dynamics of reactive oxygen species (ROS) production, Bax translocation and caspase-3 activation during bufalin-induced apoptosis in living human lung adenocarcinoma (ASTC-a-1) cells. Bufalin induced ROS production

Lei Sun; Tongsheng Chen; Xiaoping Wang; Yun Chen; Xunbin Wei

2009-01-01

267

Sources of Reactive Oxygen Species Production in Excitotoxin-Stimulated Cerebellar Granule Cells  

Microsoft Academic Search

Reactive oxygen species (ROS) production in rat cerebellar granule cells in the presence of the excitotoxinsN-methyl-d-aspartate (NMDA) and kainic acid (KA) and by the protein kinase C activator phorbol myristate acetate (PMA) was Ca2+-dependent and resulted in decreased cell viability. Exposure of stimulated cells to rotenone (a respiratory chain inhibitor) did not decrease ROS levels and did not affect short-term

Alexander A. Boldyrev; David O. Carpenter; Matthew J. Huentelman; Craig M. Peters; Peter Johnson

1999-01-01

268

Modification of reactive oxygen species scavenging capacity of chloroplasts through plastid transformation  

Microsoft Academic Search

Reactive oxygen species (ROS), including superoxide anions, hydrogen peroxide and hydroxyl radicals are generated through\\u000a normal biochemical processes, but their production is increased by abiotic stresses. The prospects for enhancing ROS scavenging,\\u000a and hence stress tolerance, by direct gene expression in a vulnerable cell compartment, the chloroplast, have been explored\\u000a in tobacco. Several plastid transformants were generated which contained either

Miranda Poage; Bénédicte Le Martret; Marcel A. K. Jansen; Gregory D. Nugent; Philip J. Dix

2011-01-01

269

Regulation of gene expression in the nervous system by reactive oxygen and nitrogen species  

Microsoft Academic Search

Reactive oxygen and nitrogen species function as direct and indirect modulators of gene expression through their interactions\\u000a with transcription factors and also key enzymes in receptor-activated signalling pathways. This regulatory role may become\\u000a displaced under certain circumstances such as aging, autoimmune responses and viral infection, leading to the pathological\\u000a outcome associated with inflammatory and degenerative diseases in the CNS.

Jean E. Merrill; Sean P. Murphy

1997-01-01

270

Inhibition of neutrophil derived lysosomal enzymes and reactive oxygen species by a novel tetrapeptide  

Microsoft Academic Search

Objective and Design: The role of a tetrapeptide derivative PEP 1261{Boc-Lys(Boc)-Arg-Asp-Ser(tBu)-OtBu}, corresponding to residues 39-42 of human lactoferrin, has been tested in vitro in the modulation of neutrophil function.¶Material and Subjects: The level of non-enzymatic mediators of inflammation such as reactive oxygen species (ROS), enzymatic mediators such as myeloperoxidase (MPO) and lysosomal enzymes have been assessed in the presence or

R. Meera; S. Anand; C. V. Ramesh; R. Puvanakrishnan

1999-01-01

271

Differential effects of reactive oxygen species on native synovial fluid and purified human umbilical cord hyaluronate  

Microsoft Academic Search

The ability of reactive oxygen species produced by triggered neutrophilic leukocytes, hypoxanthine\\/xanthine oxidase (HX\\/XAO), hydrogen peroxide, and hypochlorous acid\\/mycloperoxidase (HOC1\\/MPO) systems to degrade hyaluronate (HA) in human synovial fluid (SF) and purified umbilical cord HA was compared by measuring the molecular weight distribution of HA using high-performance liquid chromatography with a size-exclusion column. The exposure of noninflammatory SF to phorbol

Herkko Saari; Yrjö T. Konttinen; Claes Friman; Timo Sorsa

1993-01-01

272

Mitochondrial reactive oxygen species affect sensitivity to curcumin-induced apoptosis  

Microsoft Academic Search

Curcumin exhibits anticancer activity in vivo and triggers tumor cell apoptosis in vivo and in vitro. Several in vitro studies suggest that curcumin-induced apoptosis is associated with reactive oxygen species (ROS) production and\\/or oxidative stress in transformed cells. This study compared and contrasted the effects of curcumin on human skin cancer cells and their respiration-deficient (?0) clones to characterize the

Numsen Hail Jr.

2008-01-01

273

Nox4 overexpression activates reactive oxygen species and p38 MAPK in human endothelial cells  

Microsoft Academic Search

Nicotine adenine dinucleotide phosphate (NADPH) oxidase (Nox) complexes are the main sources of reactive oxygen species (ROS) formation in the vessel wall. We have used DNA microarray, real-time PCR and Western blot to demonstrate that the subunit Nox4 is the major Nox isoform in primary human endothelial cells; we also found high levels of NADPH oxidase subunit p22phox expression. Nox4

Claudia Goettsch; Winfried Goettsch; Gregor Muller; Jochen Seebach; Hans-Joachim Schnittler; Henning Morawietz

2009-01-01

274

Effect of allopurinol on the formation of reactive oxygen species during intense exercise in the horse  

Microsoft Academic Search

Allopurinol was administered to six horses in a cross-over study to determine the relative contribution of xanthine oxidase (xo) activity to the formation of reactive oxygen species (ROS) in the horse during intense exercise. Exercise increased the mean (SEM) plasma lipid hydroperioxide concentration to a maximum of 492·7 (33·4) ?M within one minute of exercise completion and maximum levels of

P. C Mills; N. C Smith; R. C Harris; P Harris

1997-01-01

275

Recent advances in fluorescent probes for the detection of reactive oxygen species  

Microsoft Academic Search

Reactive oxygen species (ROS) have captured the interest of many researchers in the chemical, biological, and medical fields\\u000a since they are thought to be associated with various pathological conditions. Fluorescent probes for the detection of ROS\\u000a are promising tools with which to enhance our understanding of the physiological roles of ROS, because they provide spatial\\u000a and temporal information about target

Nobuaki Soh

2006-01-01

276

Reactive oxygen species localization in roots of Arabidopsis thaliana seedlings grown under phosphate deficiency  

Microsoft Academic Search

Arabidopsis plants responding to phosphorus (P) deficiency increase lateral root formation and reduce primary root elongation. In addition\\u000a the number and length of root hairs increases in response to P deficiency. Here we studied the patterns of radical oxygen\\u000a species (ROS) in the roots of Arabidopsis seedlings cultured on media supplemented with high or low P concentration. We found that

Jaros?aw Tyburski; Kamila Dunajska; Andrzej Tretyn

2009-01-01

277

Role of Reactive Oxygen Species in Chronic Hypoxia-Induced Pulmonary Hypertension and Vascular Remodeling  

Microsoft Academic Search

\\u000a Pulmonary hypertension is a life-threatening disease process that affects adults and children. Pediatric patients with lung\\u000a diseases that can be complicated by alveolar hypoxia, such as bronchopulmonary dysplasia (BPD), are at risk for developing\\u000a pulmonary hypertension, which leads to right heart failure and greatly increases morbidity and mortality. We review the evidence\\u000a that reactive oxygen species (ROS) are generated by

Eva Nozik-Grayck; Kurt R. Stenmark

278

PbCrO 4 mediates cellular responses via reactive oxygen species  

Microsoft Academic Search

Exposure to certain particulate hexavalent chromium [Cr(VI)] compounds, such as lead chromate (PbCrO4), has been associated with lung cancer and respiratory tract toxicity· Previous studies indicate that the solubility of Cr(VI)-compounds is an important factor in Cr(VI)-induced carcinogenesis· The present study investigates reactive oxygen species (ROS) generation by PbCrO4 particles and cellular responses using RAW 264·7 cells· A mixture containing

Vince Castranova; Xianglin Shi

2004-01-01

279

Epidermal growth factor rescues trophoblast apoptosis induced by reactive oxygen species  

Microsoft Academic Search

Pre-eclampsia and intrauterine growth restriction are associated with increased apoptosis of placental villous trophoblast.\\u000a This may result from placental hypoperfusion, leading to the generation of reactive oxygen species (ROS). Apoptosis can be\\u000a induced in villous trophoblast following exposure to oxidative stress. Epidermal growth factor (EGF) reduces trophoblast apoptosis\\u000a resulting from exposure to hypoxia. We hypothesised that exposure to hydrogen peroxide,

Sarah J. Moll; Carolyn J. P. Jones; Ian P. Crocker; Philip N. Baker; Alexander E. P. Heazell

2007-01-01

280

Light-dependent generation of reactive oxygen species in cell culture media  

Microsoft Academic Search

Cell culture media (RPMI 1640, Dulbecco’s Minimal Essential Medium and yeast extract-peptone-glucose medium) were found to oxidize dichlorodihydrofluorescein diacetate and dihydrorhodamine 123, and to generate spin adduct of 5,5?-dimethyl-1-pyrroline N-oxide, which indicates formation of reactive oxygen species (ROS). The production of ROS was light dependent. The main component of the media responsible for the generation of ROS was riboflavin, but

Agnieszka Grzelak; B?a?ej Rychlik; Grzegorz Bartosz

2001-01-01

281

Development of an in vitro model of excess intracellular reactive oxygen species  

Microsoft Academic Search

These investigations characterize an in vitro model for generating excess intracellular reactive oxygen species (ROS). This novel model may be useful in the identification\\u000a and delineation of cellular mechanisms associated with aging due to the link between age and excess oxidative events. The\\u000a human cell line, MCF7, was stably transfected using the pSV3.neo plasmid housing a gene encoding the Aequorea

K. A. Greer; M. Pine; D. L. Busbee

2005-01-01

282

Microporous ZSM-5 zeolite anchors the exceptionally active triplet oxygen species: Mechanistic studies  

Microsoft Academic Search

Through density functional calculations, it was found that the Brönsted acidic sites in microporous zeolites (e.g., ZSM-5) can stabilize and anchor the active triplet oxygen species [i.e., O(3P)], thus providing an ideal locale for the related catalytic processes. An exemplified catalytic cycle was proposed here. The 419.3nm photolysis of singlet N2O leads to the formation of triplet N2O, which releases

Gang Yang; Jing Guan; Lijun Zhou; Xianchun Liu; Xiuwen Han; Xinhe Bao

2008-01-01

283

Reactive oxygen species and protein oxidation in aging: a look back, a look ahead.  

PubMed

The existence of free radicals, as chemical entities, was inferred 100 years ago but not universally accepted for some 30-40 years. The existence and importance of free radicals in biological systems was not recognized until the mid 1950s, by a small number of visionary scientists who can be credited with founding the field of reactive oxygen biochemistry. For most of the remaining 20th century, reactive oxygen species (ROS) were considered a type of biochemical "rusting agent" that caused stochastic tissue damage and disease. As we enter the 21st century, reactive oxygen biochemistry is maturing as a discipline and establishing its importance among the biomedical sciences. It is now recognized that virtually every disease state involves some degree of oxidative stress. Moreover, we are now beginning to recognize that ROS are produced in a well-regulated manner to help maintain homeostasis on the cellular level in normal, healthy tissue. This review summarizes the history of reactive oxygen biochemistry, outlining major paradigm shifts that the field has undergone and continues to experience. The contributions of Earl Stadtman to the recent history of the field (1980-present) are especially highlighted. The role of ROS in signal transduction is presented in some detail as central to the latest paradigm shift. Emerging technologies, particularly proteomic technologies, are discussed that will facilitate further evolution in the field of reactive oxygen biochemistry. PMID:11795897

Hensley, Kenneth; Floyd, Robert A

2002-01-15

284

Automatic flow injection based methodologies for determination of scavenging capacity against biologically relevant reactive species of oxygen and nitrogen  

Microsoft Academic Search

Redox reactions are the heart of numerous biochemical pathways found in cellular chemistry, generating reactive oxygen species (ROS) and reactive nitrogen species (RNS), that includes superoxide anion radical (O2?), hydrogen peroxide (H2O2), hydroxyl radical (HO), singlet oxygen (1O2), hypochlorite anion (OCl?), peroxynitrite anion (ONOO?) and nitric oxide radical (NO). The measurement of scavenging capacity against these reactive species presents new

Luís M. Magalhães; Marlene Lúcio; Marcela A. Segundo; Salette Reis; José L. F. C. Lima

2009-01-01

285

Diatom oxygen isotopes: Evidence of a species effect in the sediment record  

NASA Astrophysics Data System (ADS)

Diatom oxygen isotope measurements are commonly made on bulk mixed species assemblages due to the difficulty in purifying and separating individual taxa. As such, it is essential to understand processes in diatoms which may lead to isotope offsets both between and within individual species. Existing studies have suggested that mechanisms which may lead to isotopes offset in diatoms, such as vital effects, are either nonexistent or negligible. Here, we present a suite of diatom oxygen isotope data from the onset of major Northern Hemisphere Glaciation at ODP site 882 in the northwest Pacific Ocean which display large offsets (mean = 1.23‰, max = 3.51‰, error = 0.84‰) between two different size fractions (75-150 ?m and >150 ?m) that are dominated by only two species: Coscinodiscus marginatus and Coscinodiscus radiatus. These offsets are most likely size related, although additional interspecies and intraspecies effects may also be important in determining the exact magnitude of the offsets. Consequently, considerable care is needed when interpreting bulk diatom oxygen isotope data in relation to paleoenvironmental change, especially when the amount of stratigraphical change within the isotopes is small.

Swann, George E. A.; Leng, Melanie J.; Sloane, Hilary J.; Maslin, Mark A.; Onodera, Jonaotaro

2007-06-01

286

The production of toxic oxygen metabolites by hemocytes of different snail species.  

PubMed

The phagocytic hemocytes of four snail species were investigated for their ability to generate reactive oxygen metabolites upon stimulation by foreign material. Hemocytes of the pond snail Lymnaea stagnalis and of the garden snail Helix aspersa showed a luminol-dependent chemiluminescence (CL) when they phagocytosed zymosan particles. This CL was inhibited by superoxide dismutase (SOD) and sodium azide, indicating the involvement of oxygen intermediates. Hemocytes of the planorbid snails Planorbarius corneus and Biomphalaria glabrata did not give a detectable CL response. This is probably due to the presence of hemoglobin in the hemolymph; after isolation of the cells and subsequent stimulation, however, still no CL could be measured. Hemocytes of all four snail species showed a SOD-sensitive nitroblue tetrazolium (NBT) reduction, indicating the generation of superoxide anions. Regarding the NBT reaction, no differences were observed between strains of B. glabrata that were susceptible or resistant to PR-1 Schistosoma mansoni; neither did exposure to the parasite have an effect on the ability of the hemocytes to reduce NBT. Also, hemocytes from Trichobilharzia ocellata-infected L. stagnalis did not react differently from hemocytes of uninfected snails. It is now clear that phagocytically stimulated hemocytes of several molluscan species can generate reactive forms of oxygen; the relevance of this fact for the phylogeny of killing systems operative in leukocytes is discussed. PMID:3169350

Dikkeboom, R; van der Knaap, W P; van den Bovenkamp, W; Tijnagel, J M; Bayne, C J

1988-01-01

287

Effect of caloric restriction on mitochondrial reactive oxygen species production and bioenergetics: reversal by insulin.  

PubMed

To gain insight into the antiaging mechanisms of caloric restriction (CR), mitochondria from liver tissue of male Brown Norway rats were used to study the effects of CR and insulin on mitochondrial reactive oxygen species production and bioenergetics. As assessed by hydrogen peroxide measurement, CR resulted in a decrease in the production rate of reactive oxygen species. This decrease was attributed to a decrease in protonmotive force in mitochondria from the CR animals. The decrease in protonmotive force resulted from an increase in proton leak activity and a concomitant decrease in substrate oxidation activity. Each of these effects of CR was reversed by subjecting CR animals to 2 wk of insulin treatment. To achieve continuous and stable insulin delivery, animals were placed under temporary halothane anesthesia and miniosmotic pumps were implanted subcutaneously. To gain further insight into how CR and insulin exerted its effects on mitochondrial bioenergetics, the effects of CR and insulin were quantified using modular metabolic control analysis. This analysis revealed that the effects of CR were transmitted through different reaction branches of the bioenergetic system, and insulin reversed the effects of CR by acting through the same branches. These results provide a plausible mechanism by which mitochondrial reactive oxygen species production is lowered by CR and a complete description of the effects of CR on mitochondrial bioenergetics. They also indicate that these changes may be due to lowered insulin concentrations and altered insulin signaling in the CR animal. PMID:12969875

Lambert, A J; Merry, B J

2003-09-11

288

[Effects of allelochemical dibutyl phthalate on Gymnodinium breve reactive oxygen species].  

PubMed

The purpose of this study was to investigate the mechanism of inhibitory action of dibutyl phthalate (DBP) on red tide algae Gymnodinium breve. Reactive oxygen species (ROS) level, contents of *OH and H2O2, and O2*(-) production rate were investigated, and also for the effects of electron transfer inhibitors on the ROS induction of DBP. The results showed that DBP triggered the synthesis of reactive oxygen species ROS, and with the increase of concentration of DBP, *OH and H2O2 contents in cells accumulated, as for the 3 mg x L(-1) DBP treated algae cultures, OH showed a peak of 33 U x mL(-1) at 48 h, which was about 2. 4 times higher than that in the controlled, and H2O2 contents was about 250 nmol x (10(7) cells)(-1) at 72 h, which was about 5 times higher and also was the highest during the whole culture. Rotenone (an inhibitor of complex I in the mitochondria electron transport chain) decreased the DBP induced ROS production, and dicumarol (an inhibitor of the redox enzyme system in the plasma membrane) stimulated the DBP induced ROS production. Taken all together, the results demonstrated DBP induced over production of reactive oxygen species in G. breve, which is the main inhibitory mechanism, and mitochondria and plasma membrane seem to be the main target site of DBP. These conclusions were of scientific meaning on uncovering the inhibitory mechanism of allelochemical on algae. PMID:22509579

Bie, Cong-Cong; Li, Feng-Min; Li, Yuan-Yuan; Wang, Zhen-Yu

2012-02-01

289

Annato extract and ?-carotene modulate the production of reactive oxygen species/nitric oxide in neutrophils from diabetic rats.  

PubMed

Annatto has been identified as carotenoids that have antioxidative effects. It is well known that one of the key elements in the development of diabetic complications is oxidative stress. The immune system is especially vulnerable to oxidative damage because many immune cells, such as neutrophils, produce reactive oxygen species and reactive nitrogen species as part of the body's defense mechanisms to destroy invading pathogens. Reactive oxygen species/reactive nitrogen species are excessively produced by active peripheral neutrophils, and may damage essential cellular components, which in turn can cause vascular complications in diabetes. The present study was undertaken to evaluate the possible protective effects of annatto on the reactive oxygen species and nitric oxide (NO) inhibition in neutrophils from alloxan-induced diabetic rats. Adult female rats were divided into six groups based on receiving either a standard diet with or without supplementation of annatto extract or beta carotene. All animals were sacrificed 30 days after treatment and the neutrophils were isolated using two gradients of different densities. The reactive oxygen species and NO were quantified by a chemiluminescence and spectrophotometric assays, respectively. Our results show that neutrophils from diabetic animals produce significantly more reactive oxygen species and NO than their respective controls and that supplementation with beta carotene and annatto is able to modulate the production of these species. Annatto extract may have therapeutic potential for modulation of the balance reactive oxygen species/NO induced by diabetes. PMID:22573917

Rossoni-Júnior, Joamyr Victor; Araújo, Glaucy Rodrigues; Pádua, Bruno da Cruz; Chaves, Míriam Martins; Pedrosa, Maria Lúcia; Silva, Marcelo Eustáquio; Costa, Daniela Caldeira

2011-12-07

290

Annato extract and ?-carotene modulate the production of reactive oxygen species/nitric oxide in neutrophils from diabetic rats  

PubMed Central

Annatto has been identified as carotenoids that have antioxidative effects. It is well known that one of the key elements in the development of diabetic complications is oxidative stress. The immune system is especially vulnerable to oxidative damage because many immune cells, such as neutrophils, produce reactive oxygen species and reactive nitrogen species as part of the body’s defense mechanisms to destroy invading pathogens. Reactive oxygen species/reactive nitrogen species are excessively produced by active peripheral neutrophils, and may damage essential cellular components, which in turn can cause vascular complications in diabetes. The present study was undertaken to evaluate the possible protective effects of annatto on the reactive oxygen species and nitric oxide (NO) inhibition in neutrophils from alloxan-induced diabetic rats. Adult female rats were divided into six groups based on receiving either a standard diet with or without supplementation of annatto extract or beta carotene. All animals were sacrificed 30 days after treatment and the neutrophils were isolated using two gradients of different densities. The reactive oxygen species and NO were quantified by a chemiluminescence and spectrophotometric assays, respectively. Our results show that neutrophils from diabetic animals produce significantly more reactive oxygen species and NO than their respective controls and that supplementation with beta carotene and annatto is able to modulate the production of these species. Annatto extract may have therapeutic potential for modulation of the balance reactive oxygen species/NO induced by diabetes.

Rossoni-Junior, Joamyr Victor; Araujo, Glaucy Rodrigues; Padua, Bruno da Cruz; Chaves, Miriam Martins; Pedrosa, Maria Lucia; Silva, Marcelo Eustaquio; Costa, Daniela Caldeira

2012-01-01

291

Retrofitted gravity mediation without the gravitino-overproduction problem  

SciTech Connect

We propose a retrofitted gravity-mediation model which alleviates the gravitino overproduction from decays of an inflaton and a supersymmetry breaking field. In the model, we introduce an approximate U(1) symmetry under which the supersymmetry breaking field is charged, although it is broken by a mass term of messenger fields to generate gaugino masses of order the weak scale. In a low-scale inflation model, we find regions in which the gravitino-overproduction problem is avoided.

Endo, Motoi; Takahashi, Fuminobu [Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); Yanagida, T. T. [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Research Center for the Early Universe, University of Tokyo, Tokyo 113-0033 (Japan)

2007-10-15

292

Inactivation effects of neutral reactive-oxygen species on Penicillium digitatum spores using non-equilibrium atmospheric-pressure oxygen radical source  

NASA Astrophysics Data System (ADS)

The effectiveness of atomic and excited molecular oxygen species at inactivating Penicillium digitatum spores was quantitatively investigated by measuring these species and evaluating the spore inactivation rate. To avoid the effects of ultraviolet light and charged species, a non-equilibrium atmospheric-pressure radical source, which supplies only neutral radicals, was employed. Ground-state atomic oxygen (O(3Pj)) and excited molecular oxygen (O2(1?g)) species were measured using vacuum ultraviolet absorption spectroscopy. The inactivation rate of spores was evaluated using the colony count method. The lifetimes of O(3Pj) and O2(1?g) in an argon gas ambient at atmospheric pressure were found to be about 0.5 ms and much more than tens of ms, and their spore inactivation rates were about 10-17 cm3 s-1 and much lower than 10-21 cm3 s-1, respectively.

Hashizume, Hiroshi; Ohta, Takayuki; Fengdong, Jia; Takeda, Keigo; Ishikawa, Kenji; Hori, Masaru; Ito, Masafumi

2013-10-01

293

Arsenic species that cause release of iron from ferritin and generation of activated oxygen.  

PubMed

The in vitro effects of four different species of arsenic (arsenate, arsenite, monomethylarsonic acid, and dimethylarsinic acid) in mobilizing iron from horse spleen ferritin under aerobic and anaerobic conditions were investigated. Dimethylarsinic acid (DMA(V)) and dimethylarsinous acid (DMA(III)) significantly released iron from horse spleen ferritin either with or without the presence of ascorbic acid, a strong synergistic agent. Ascorbic acid-mediated iron release was time-dependent as well as both DMA(III) and ferritin concentration-dependent. Iron release from ferritin by DMA(III)) alone or with ascorbic acid was not significantly inhibited by superoxide dismutase (150 or 300 units/ml). However, the iron release was greater under anaerobic conditions (nitrogen gas), which indicates direct chemical reduction of iron from ferritin by DMA(III), with or without ascorbic acid. Both DMA(V) and DMA(III)) released iron from both horse spleen and human liver ferritin. Further, the release of ferritin iron by DMA(III)) with ascorbic acid catalyzed bleomycin-dependent degradation of calf thymus DNA. These results indicate that exogenous methylated arsenic species and endogenous ascorbic acid can cause (a) the release of iron from ferritin, (b) the iron-dependent formation of reactive oxygen species, and (c) DNA damage. This reactive oxygen species pathway could be a mechanism of action of arsenic carcinogenesis in man. PMID:11068869

Ahmad, S; Kitchin, K T; Cullen, W R

2000-10-15

294

In vitro scavenging capacity of annatto seed extracts against reactive oxygen and nitrogen species.  

PubMed

Bixa orellana L. (annatto), from Bixaceae family, is a native plant of tropical America, which accumulates several carotenoids (including bixin and norbixin), terpenoids, tocotrienols and flavonoids with potential antioxidant activity. In the present study, the in vitro scavenging capacity of annatto seed extracts against reactive oxygen species (ROS) and reactive nitrogen species (RNS) was evaluated and compared to the bixin standard. Annatto extracts were obtained using solvents with different polarities and their phenolic compounds and bixin levels were determined by high performance liquid chromatography coupled to diode array detector. All annatto extracts were able to scavenge all the reactive species tested at the low ?g/mL range, with the exception of superoxide radical. The ethanol:ethyl acetate and ethyl acetate extracts of annatto seeds, which presented the highest levels of hypolaetin and bixin, respectively, were the extracts with the highest antioxidant capacity, although bixin standard presented the lowest IC(50) values. PMID:23140681

Chisté, Renan Campos; Mercadante, Adriana Zerlotti; Gomes, Ana; Fernandes, Eduarda; Lima, José Luís Fontes da Costa; Bragagnolo, Neura

2011-01-08

295

Light-responsive polymer nanoreactors: a source of reactive oxygen species on demand.  

PubMed

Various domains present the challenges of responding to stimuli in a specific manner, with the desired sensitivity or functionality, and only when required. Stimuli-responsive systems that are appropriately designed can effectively meet these challenges. Here, we introduce nanoreactors that encapsulate photosensitizer-protein conjugates in polymer vesicles as a source of "on demand" reactive oxygen species. Vesicles made of poly(2-methyloxazoline)-poly(dimethylsiloxane)-poly(2-methyloxazoline) successfully encapsulated the photosensitizer Rose Bengal-bovine serum albumin conjugate (RB-BSA) during a self-assembly process, as demonstrated by UV-Vis spectroscopy. A combination of light scattering and transmission electron microscopy indicated that the nanoreactors are stable over time. They serve a dual role: protecting the photosensitizer in the inner cavity and producing in situ reactive oxygen species (ROS) upon irradiation with appropriate electromagnetic radiation. Illumination with appropriate wavelength light allows us to switch on/off and to control the production of ROS. Because of the oxygen-permeable nature of the polymer membrane of vesicles, ROS escape into the environment around vesicles, as established by electron paramagnetic resonance. The light-sensitive nanoreactor is taken up by HeLa cells in a Trojan horse fashion: it is nontoxic and, when irradiated with the appropriate laser light, produces ROS that induce cell death in a precise area corresponding to the irradiation zone. These nanoreactors can be used in theranostic approaches because they can be detected via the fluorescent photosensitizer signal and simultaneously produce ROS efficiently "on demand". PMID:23154601

Baumann, Patric; Balasubramanian, Vimalkumar; Onaca-Fischer, Ozana; Sienkiewicz, Andrzej; Palivan, Cornelia G

2012-11-15

296

Antimicrobial strategies centered around reactive oxygen species - bactericidal antibiotics, photodynamic therapy, and beyond.  

PubMed

Reactive oxygen species (ROS) can attack a diverse range of targets to exert antimicrobial activity, which accounts for their versatility in mediating host defense against a broad range of pathogens. Most ROS are formed by the partial reduction in molecular oxygen. Four major ROS are recognized comprising superoxide (O2 •-), hydrogen peroxide (H2 O2 ), hydroxyl radical ((•) OH), and singlet oxygen ((1) O2 ), but they display very different kinetics and levels of activity. The effects of O2 •- and H2 O2 are less acute than those of •OH and (1) O2 , because the former are much less reactive and can be detoxified by endogenous antioxidants (both enzymatic and nonenzymatic) that are induced by oxidative stress. In contrast, no enzyme can detoxify (•) OH or (1) O2 , making them extremely toxic and acutely lethal. The present review will highlight the various methods of ROS formation and their mechanism of action. Antioxidant defenses against ROS in microbial cells and the use of ROS by antimicrobial host defense systems are covered. Antimicrobial approaches primarily utilizing ROS comprise both bactericidal antibiotics and nonpharmacological methods such as photodynamic therapy, titanium dioxide photocatalysis, cold plasma, and medicinal honey. A brief final section covers reactive nitrogen species and related therapeutics, such as acidified nitrite and nitric oxide-releasing nanoparticles. PMID:23802986

Vatansever, Fatma; de Melo, Wanessa C M A; Avci, Pinar; Vecchio, Daniela; Sadasivam, Magesh; Gupta, Asheesh; Chandran, Rakkiyappan; Karimi, Mahdi; Parizotto, Nivaldo A; Yin, Rui; Tegos, George P; Hamblin, Michael R

2013-07-25

297

Cytotoxicity of InP/ZnS quantum dots related to reactive oxygen species generation  

NASA Astrophysics Data System (ADS)

Indium phosphide (InP) quantum dots (QDs) have emerged as a presumably less hazardous alternative to cadmium-based particles, but their cytotoxicity has not been well examined. Although their constituent elements are of very low toxicity to cells in culture, they nonetheless exhibit phototoxicity related to generation of reactive oxygen species by excited electrons and/or holes interacting with water and molecular oxygen. Using spin-trap electron paramagnetic resonance (EPR) spectroscopy and reporter assays, we find a considerable amount of superoxide and a small amount of hydroxyl radical formed under visible illumination of biocompatible InP QDs with a single ZnS shell, comparable to what is seen with CdTe. A double thickness shell reduces the reactive oxygen species concentration approximately two-fold. Survival assays in five cell lines correspondingly indicate a distinct reduction in toxicity with the double-shell InP QDs. Toxicity varies significantly across cell lines according to the efficiency of uptake, being overall significantly less than what is seen with CdTe or CdSe/ZnS. This indicates that InP QDs are a useful alternative to cadmium-containing QDs, while remaining capable of electron-transfer processes that may be undesirable or which may be exploited for photosensitization applications.

Chibli, Hicham; Carlini, Lina; Park, Soonhyang; Dimitrijevic, Nada M.; Nadeau, Jay L.

2011-06-01

298

Asbestos induces apoptosis of human and rabbit pleural mesothelial cells via reactive oxygen species.  

PubMed Central

Mesothelial cells, the progenitor cell of the asbestos-induced tumor mesothelioma, are particularly sensitive to the toxic effects of asbestos, although the molecular mechanisms by which asbestos induces injury in mesothelial cells are not known. We asked whether asbestos induced apoptosis in mesothelial cells and whether reactive oxygen species were important. Pleural mesothelial cells (rabbit or human) were exposed to asbestos (crocidolite, amosite, or chrysotile) or control particles at moderate doses (1-10 microg/cm2) over 24 h and evaluated for oligonucleosomal DNA fragmentation, loss of membrane phospholipid asymmetry, and nuclear condensation. Asbestos fibers, not control particles, induced apoptosis in mesothelial cells by all assays and induction of apoptosis was dose dependent for all types of asbestos, with crocidolite (5 microg/cm2) inducing 15.0+/-1.1% (mean+/-SE; n = 12) apoptosis versus control particles < 4%. Apoptosis induced by asbestos, but not by actinomycin D, was inhibited by extracellular catalase, superoxide dismutase in the presence of catalase, hypoxia (8% oxygen), deferoxamine, 3-aminobenzamide [an inhibitor of poly(ADP-ribosyl) polymerase], and cytochalasin B. Only catalase and cytochalasin B decreased fiber uptake. We conclude that asbestos induces apoptosis in mesothelial cells via reactive oxygen species. Escape from this pathway could allow the abnormal survival of mesothelial cells with asbestos-induced mutations.

Broaddus, V C; Yang, L; Scavo, L M; Ernst, J D; Boylan, A M

1996-01-01

299

Cytotoxicity of InP/ZnS quantum dots related to reactive oxygen species generation.  

PubMed

Indium phosphide (InP) quantum dots (QDs) have emerged as a presumably less hazardous alternative to cadmium-based particles, but their cytotoxicity has not been well examined. Although their constituent elements are of very low toxicity to cells in culture, they nonetheless exhibit phototoxicity related to generation of reactive oxygen species by excited electrons and/or holes interacting with water and molecular oxygen. Using spin-trap electron paramagnetic resonance (EPR) spectroscopy and reporter assays, we find a considerable amount of superoxide and a small amount of hydroxyl radical formed under visible illumination of biocompatible InP QDs with a single ZnS shell, comparable to what is seen with CdTe. A double thickness shell reduces the reactive oxygen species concentration approximately two-fold. Survival assays in five cell lines correspondingly indicate a distinct reduction in toxicity with the double-shell InP QDs. Toxicity varies significantly across cell lines according to the efficiency of uptake, being overall significantly less than what is seen with CdTe or CdSe/ZnS. This indicates that InP QDs are a useful alternative to cadmium-containing QDs, while remaining capable of electron-transfer processes that may be undesirable or which may be exploited for photosensitization applications. PMID:21509403

Chibli, Hicham; Carlini, Lina; Park, Soonhyang; Dimitrijevic, Nada M; Nadeau, Jay L

2011-04-21

300

DNA Oxidation by Reactive Oxygen Species Produced by Atmospheric Pressure Microplasmas  

NASA Astrophysics Data System (ADS)

Arrays of microcathode sustained discharges (MCSD's) have been ­developed for the production of high fluxes of singlet delta oxygen (SDO) and ozone (O3) at atmospheric pressure. SDO and O3 densities higher than 1017 and 1016 cm-3, respectively, have been efficiently produced and transported over distances longer than 50 cm. These arrays of MCSD's have been optimized to supply well-quantified and tunable fluxes of either SDO or O3. This plasma source has been found to be very useful for examining the reactivity of these reactive oxygen species with biological components. Preliminary results indicate that both SDO and O3 are able to oxidize DNA, originating great damages in DNA such as single- and double-strand breaks and base oxidation. It has been observed that while all bases of DNA are almost indifferently and quite effectively oxidized by O3, SDO reacts mainly with guanine.

Sousa, Joao Santos; Girard, Pierre-Marie; Sage, Evelyne; Ravanat, Jean-Luc; Puech, Vincent

301

Involvement of reactive oxygen species in the electrochemical inhibition of barnacle (Amphibalanus amphitrite) settlement.  

PubMed

The role of reactive oxygen species (ROS) in electrochemical biofouling inhibition was investigated using a series of abiotic tests and settlement experiments with larvae of the barnacle Amphibalanus amphitrite, a cosmopolitan fouler. Larval settlement, a measure of biofouling potential, was reduced from 43% +/- 14% to 5% +/- 6% upon the application of pulsed electric signals. The application of ROS scavengers such as glutathione and catalase counteracted the inhibitory effects of the electric signals, allowing settlement, and thus indicating that ROS are antifouling agents. Based on the experimental evidence, the proposed mechanism for ROS-based fouling prevention with interdigitated electrodes involved the electrochemical generation of hydrogen peroxide by oxygen reduction, and its likely reduction to hydroxyl radicals. Either hydroxyl radicals or products of hydroxyl radical reactions appeared to be the main deterrents of larval settlement. PMID:19449240

Pérez-Roa, Rodolfo E; Anderson, Marc A; Rittschof, Dan; Hunt, Christopher G; Noguera, Daniel R

2009-01-01

302

Chemistry and biology of reactive oxygen species in signaling or stress responses  

PubMed Central

Reactive oxygen species (ROS) are a family of molecules that are continuously generated, transformed and consumed in all living organisms as a consequence of aerobic life. The traditional view of these reactive oxygen metabolites is one of oxidative stress and damage that leads to decline of tissue and organ systems in aging and disease. However, emerging data show that ROS produced in certain situations can also contribute to physiology and increased fitness. This Perspective provides a focused discussion on what factors lead ROS molecules to become signal and/or stress agents, highlighting how increasing knowledge of the underlying chemistry of ROS can lead to advances in understanding their disparate contributions to biology. An important facet of this emerging area at the chemistry-biology interface is the development of new tools to study these small molecules and their reactivity in complex biological systems.

dickinson, Bryan C; Chang, Christopher J

2012-01-01

303

Communication: CO oxidation by silver and gold cluster cations: Identification of different active oxygen species  

SciTech Connect

The oxidation of carbon monoxide with nitrous oxide on mass-selected Au{sub 3}{sup +} and Ag{sub 3}{sup +} clusters has been investigated under multicollision conditions in an octopole ion trap experiment. The comparative study reveals that for both gold and silver cations carbon dioxide is formed on the clusters. However, whereas in the case of Au{sub 3}{sup +} the cluster itself acts as reactive species that facilitates the formation of CO{sub 2} from N{sub 2}O and CO, for silver the oxidized clusters Ag{sub 3}O{sub x}{sup +} (n= 1-3) are identified as active in the CO oxidation reaction. Thus, in the case of the silver cluster cations N{sub 2}O is dissociated and one oxygen atom is suggested to directly react with CO, whereas a second kind of oxygen strongly bound to silver is acting as a substrate for the reaction.

Popolan, Denisia M.; Bernhardt, Thorsten M. [Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm (Germany)

2011-03-07

304

Cell death from antibiotics without the involvement of reactive oxygen species.  

PubMed

Recent observations have suggested that classic antibiotics kill bacteria by stimulating the formation of reactive oxygen species (ROS). If true, this notion might guide new strategies to improve antibiotic efficacy. In this study, the model was directly tested. Contrary to the hypothesis, antibiotic treatment did not accelerate the formation of hydrogen peroxide in Escherichia coli and did not elevate intracellular free iron, an essential reactant for the production of lethal damage. Lethality persisted in the absence of oxygen, and DNA repair mutants were not hypersensitive, undermining the idea that toxicity arose from oxidative DNA lesions. We conclude that these antibiotic exposures did not produce ROS and that lethality more likely resulted from the direct inhibition of cell-wall assembly, protein synthesis, and DNA replication. PMID:23471409

Liu, Yuanyuan; Imlay, James A

2013-03-01

305

Involvement of reactive oxygen species in angiotensin II-induced endothelin-1 gene expression in rat cardiac fibroblasts  

Microsoft Academic Search

ObjectivesThe aim of this study was to investigate the effects of angiotensin II (Ang II) on fibroblast proliferation and endothelin-1 (ET-1) gene induction, focusing especially on reactive oxygen species (ROS)-mediated signaling in cardiac fibroblasts.

Tzu-Hurng Cheng; Pao-Yun Cheng; Neng-Lang Shih; Iuan-Bor Chen; Danny Ling Wang; Jin-Jer Chen

2003-01-01

306

N-acetylcysteine prevents reactive oxygen species–mediated myocardial stress in patients undergoing cardiac surgery: results of a randomized, double-blind, placebo-controlled clinical trial  

Microsoft Academic Search

ObjectiveReactive oxygen species have been shown to contribute to myocardial stress in patients undergoing cardiac surgery, as demonstrated by myocardial 8-iso-prostaglandin-F2? and nitrotyrosine formation. We hypothesized that the reactive oxygen species scavenger N-acetylcysteine attenuates reactive oxygen species–mediated myocardial stress in patients undergoing cardiac surgery.

Paschalis Tossios; Wilhelm Bloch; Astrid Huebner; M. Reza Raji; Fotini Dodos; Oliver Klass; Michael Suedkamp; Stefan-Mario Kasper; Martin Hellmich; Uwe Mehlhorn

2003-01-01

307

Production of reactive oxygen species by isolated mitochondria of the Antarctic bivalve Laternula elliptica (King and Broderip) under heat stress  

Microsoft Academic Search

Formation of reactive oxygen species (ROS) in mitochondrial isolates from gill tissues of the Antarctic polar bivalve Laternula elliptica was measured fluorimetrically under in vitro conditions. When compared to the rates measured at habitat temperature (1 °C), significantly elevated ROS formation was found under temperature stress of 7 °C and higher. ROS formation correlated significantly with oxygen consumption in individual

K. Heise; S. Puntarulo; H. O. Portner; D. Abele

2003-01-01

308

Reactive oxygen species in spermatozoa: methods for monitoring and significance for the origins of genetic disease and infertility  

Microsoft Academic Search

Human spermatozoa generate low levels of reactive oxygen species in order to stimulate key events, such as tyrosine phosphorylation, associated with sperm capacitation. However, if the generation of these potentially pernicious oxygen metabolites becomes elevated for any reason, spermatozoa possess a limited capacity to protect themselves from oxidative stress. As a consequence, exposure of human spermatozoa to intrinsically- or extrinsically-

Mark A Baker; R John Aitken

2005-01-01

309

Antagonistic effect of flavonoids on NSC-741909-mediated antitumor activity via scavenging of reactive oxygen species.  

PubMed

NSC-741909 (1-[(4-chlorophenyl)methyl]-1H-Indole-3-methanol) is a novel anticancer agent that is highly active against several NCI-60 cancer cell lines. This agent induces sustained activation of mitogen-activated protein kinases (MAPK), including JNK and p38 MAP kinases. However, the mechanisms of its selective antitumor activity in some cancer cell lines remain unknown. We tested the combined effects of NSC-741909 and several kinase inhibitors that target the Raf/MEK/ERK1/2 or PI3K/AKT pathways in two sensitive lung cancer cells. We found that PD98059 (2'-amino-3'-methoxyflavone), a flavone derivative and a selective MEK inhibitor, can dramatically block the cell killing effect of NSC-741909. To determine whether this inhibitory effect is associated with MEK inhibition or other mechanisms, we evaluated the effects of other MEK inhibitors with different chemical structures and flavone derivatives that do not have an effect on MEK. We found that several flavonoids can markedly block NSC-741909-induced apoptosis and JNK activation in a time-dependent manner, regardless of whether they inhibit MEK or not. In contrast, NSC-741909-induced JNK activation and apoptosis were not blocked by other MEK-specific inhibitors U0126 and CI1040. Our results also showed that NSC-741909 induced a dramatic increase of reactive oxygen species in sensitive cells and that flavonoids effectively blocked the NSC-741909-induced reactive oxygen species production which are associated with flavonoids' antagonistic effects on NSC-741909-induced JNK activation and apoptosis. Those results demonstrated that flavonoids-mediated antagonist effect is through scavenging of reactive oxygen species. Our results may have implication on the design of clinical evaluation of antitumor activity of NSC-741909 or its analogues. PMID:20854805

Guo, Wei; Wei, Xiaoli; Wu, Shuhong; Wang, Li; Peng, Henry; Wang, Ji; Fang, Bingliang

2010-09-18

310

Antagonistic effect of flavonoids on NSC-741909-mediated antitumor activity via scavenging of reactive oxygen species  

PubMed Central

NSC-741909 (1-[(4-chlorophenyl)methyl]-1H-Indole-3-methanol) is a novel anticancer agent that is highly active against several NCI-60 cancer cell lines. This agent induces sustained activation of mitogen-activated protein kinases (MAPK), including JNK and p38 MAP kinases. However, the mechanisms of its selective anti-tumor activity in some cancer cell lines remain unknown. We tested the combined effects of NSC-741909 and several kinase inhibitors that target the Raf/MEK/ERK1/2 or PI3K/AKT pathways in two sensitive lung cancer cells. We found that PD98059 (2'-amino-3'-methoxyflavone), a flavone derivative and a selective MEK inhibitor, can dramatically block the cell killing effect of NSC-741909. To determine whether this inhibitory effect is associated with MEK inhibition or other mechanisms, we evaluated the effects of other MEK inhibitors with different chemical structures and flavone derivatives that do not have an effect on MEK. We found that several flavonoids can markedly block NSC-741909-induced apoptosis and JNK activation in a time-dependent manner, regardless of whether they inhibit MEK or not. In contrast, NSC-741909-induced JNK activation and apoptosis were not blocked by other MEK-specific inhibitors U0126 and CI-1040. Our results also showed that NSC-741909 induced a dramatic increase of reactive oxygen species in sensitive cells and that flavonoids effectively blocked the NSC-741909-induced reactive oxygen species production which are associated with flavonoids’ antagonistic effects on NSC-741909-induced JNK activation and apoptosis. Those results demonstrated that flavonoids mediated antagonist effect is through scavenging of reactive oxygen species. Our results may have implication on the design of clinical evaluation of antitumor activity of NSC-741909 or its analogues.

Guo, Wei; Wei, Xiaoli; Wu, Shuhong; Wang, Li; Peng, Henry; Wang, Ji; Fang, Bingliang

2010-01-01

311

Modulation of Ca2+-activated K+ channel in renal artery endothelium in situ by nitric oxide and reactive oxygen species  

Microsoft Academic Search

Modulation of Ca2+-activated K+ channel in renal artery endothelium in situ by nitric oxide and reactive oxygen species.BackgroundEndothelium-derived nitric oxide and reactive oxygen species (ROS) have been proposed to regulate vascular tone by complex mechanisms, including the modulation of ion channel function. In endothelial function itself, activation of Ca2+-activated K+ channels (KCa) plays a crucial role by inducing hyperpolarization, which

Susanne Brakemeier; Ines Eichler; Andrea Knorr; Til Fassheber; Ralf Köhler; Joachim Hoyer

2003-01-01

312

Pentosidine in advanced glycation end-products (AGEs) during UVA irradiation generates active oxygen species and impairs human dermal fibroblasts  

Microsoft Academic Search

Our previous study reported that advanced glycation end-products (AGE)-modified BSA produced active oxygen species, O2?, H2O2, and OH under UVA irradiation and enhanced the cytotoxicity of UVA light. We examined whether pentosidine in AGE-modified BSA was involved in one of the mechanisms generating the active oxygen species. In biological investigations, fibroblasts exposed to UVA (20 J\\/cm2) in the presence of

Yuri Okano; Hitoshi Masaki; Hiromu Sakurai

2001-01-01

313

Reactive oxygen species amplify protein kinase C signaling in high glucose-induced fibronectin expression by human peritoneal mesothelial cells  

Microsoft Academic Search

Reactive oxygen species amplify protein kinase C signaling in high glucose-induced fibronectin expression by human peritoneal mesothelial cells.BackgroundWe previously demonstrated that high glucose up-regulates fibronectin mRNA and protein expression by human peritoneal mesothelial cells (HPMC) through activation of protein kinase C (PKC). PKC is known to induce cellular reactive oxygen species (ROS) and PKC-dependent activation of the reduced form of

HI BAHL LEE; MI RA YU; JAE SOOK SONG; HUNJOO HA

2004-01-01

314

Culture media and their components differ in their ability to scavenge reactive oxygen species in the plasmid relaxation assay  

Microsoft Academic Search

Objective: To investigate the modulation of DNA-damaging effects of reactive oxygen species by media composition.Design: In vitro study.Setting: Academic medical center.Patient(s): None.Intervention(s): None.Main Outcome Measure(s): Plasmid relaxation.Result(s): Ham’s F-10 medium, 1% Percoll, superoxide dismutase (1, 10, or 100 IU), and synthetic serum substitute did not affect DNA damage by reactive oxygen species and did not have any effect on plasmid

Alexander Ermilov; Michael P Diamond; Anthony G Sacco; Dmitri D Dozortsev

1999-01-01

315

Evolving concepts of oxidative stress and reactive oxygen species in cardiovascular disease.  

PubMed

Cardiovascular disease (CVD) continues to be a substantial health-care burden, despite recent treatment advances. Oxidative stress has long been regarded as a key pathophysiological mediator that ultimately leads to CVD including atherosclerosis, hypertension and heart failure. Over the past decade, emerging evidence has shifted our understanding of reactive oxygen species (ROS) from its harmful role to being signaling molecules. Here, we reviewed recent advances in our understanding of ROS that mediate the complex process of CVDs, with a focus on major ROS signaling and sources such as mitochondria and Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidases. PMID:22956414

Chen, Kai; Keaney, John F

2012-10-01

316

Malonaldehyde formation and DNA fragmentation: two independent sperm decays linked to reactive oxygen species.  

PubMed

Malondialdehyde (MDA), a product involved in membrane lipid peroxidation, was dosed in the sperm of 163 patients who had consulted the clinic regarding hypofertility. We attempted to determine if there was correlation between MDA content, sperm World Health Organization parameters and DNA fragmentation that results mainly from reactive oxygen species assaults. We found that no correlation could be established; however MDA and sperm decondensation were shown to be significantly linked. The impact of membrane polyunsaturated fatty acids and the role of phospholipid hydroperoxide glutathione peroxidase are discussed. PMID:20331908

Montjean, Debbie; Ménézo, Yves; Benkhalifa, Moncef; Cohen, Marc; Belloc, Stephanie; Cohen-Bacrie, Paul; de Mouzon, Jacques

2010-03-24

317

Generation of reactive oxygen species and photon emission from a browned product.  

PubMed

The properties of photon emission arising from a browned product were investigated. The photon intensity of the browned product was proportional to the absorbancy at 420 nm, and was influenced by the amino acid structure. The fluorescence spectrum showed similar compounds in the browned product to be related with this photon emission. Superoxide and hydrogen peroxide contributed highly to this photon emission, and several redox compounds enhanced the photon intensity at appropriate concentrations. Our work suggests that the photon intensity was closely related to the reactive oxygen species (ROS) generated from the browned product, and this effect may be utilized to evaluate the function and quality of browned food. PMID:12353622

Iida, Tetsuo; Yoshiki, Yumiko; Someya, Shinich; Okubo, Kazuyoshi

2002-08-01

318

Mitochondrial reactive oxygen species generation in obese non-diabetic and type 2 diabetic participants  

Microsoft Academic Search

Aims\\/hypothesis  The aim of this study was to measure mitochondrial reactive oxygen species (ROS) production directly from skeletal muscle\\u000a biopsies obtained from obese insulin-resistant non-diabetic and type 2 diabetic participants.\\u000a \\u000a \\u000a \\u000a Methods  Ten lean healthy, ten obese non-diabetic and ten type 2 diabetic participants received a euglycaemic–hyperinsulinaemic clamp\\u000a to measure whole body insulin sensitivity. Mitochondria were isolated from skeletal muscle biopsies, and mitochondrial

M. A. Abdul-Ghani; R. Jani; A. Chavez; M. Molina-Carrion; D. Tripathy; R. A. DeFronzo

2009-01-01

319

Update: Ralstonia species associated with Vapotherm oxygen delivery devices--United States, 2005.  

PubMed

This report updates information on Ralstonia species associated with Vapotherm oxygen delivery devices (Vapotherm Inc., Stevensville, Maryland). CDC has obtained new information from a test developed by CDC and performed by The Children's Hospital of Philadelphia (Pennsylvania) to assess the efficacy of the new chlorine dioxide disinfection protocol recommended by Vapotherm. Although limited, this information suggests that the new protocol for disinfecting Vapotherm devices and cartridges might not achieve sustained bacterial control in certain situations. At this time, the optimal protocol to disinfect machines and cartridges that might contain very heavy biofilms is not known. PMID:16267498

2005-11-01

320

Damaged DNA Binding Protein 2 in Reactive Oxygen Species (ROS) Regulation and Premature Senescence  

PubMed Central

Premature senescence induced by DNA damage or oncogene is a critical mechanism of tumor suppression. Reactive oxygen species (ROS) have been implicated in the induction of premature senescence response. Several pathological disorders such as cancer, aging and age related neurological abnormalities have been linked to ROS deregulation. Here, we discuss how Damaged DNA binding Protein-2 (DDB2), a nucleotide excision repair protein, plays an important role in ROS regulation by epigenetically repressing the antioxidant genes MnSOD and Catalase. We further revisit a model in which DDB2 plays an instrumental role in DNA damage induced ROS accumulation, ROS induced premature senescence and inhibition of skin tumorigenesis.

Roy, Nilotpal; Bagchi, Srilata; Raychaudhuri, Pradip

2012-01-01

321

Calcium and mitochondrial reactive oxygen species generation: how to read the facts.  

PubMed

A number of recent discoveries indicate that abnormal Ca2+ signaling, oxidative stress, and mitochondrial dysfunction are involved in the neuronal damage in Alzheimer's disease. However, the literature on the interactions between these factors is controversial especially in the interpretation of the cause-effect relationship between mitochondrial damage induced by Ca2+ overload and the production of reactive oxygen species (ROS). In this review, we survey the experimental observations on the Ca2+-induced mitochondrial ROS production, explain the sources of controversy in interpreting these results, and discuss the different molecular mechanisms underlying the effect of Ca2+ on the ROS emission by brain mitochondria. PMID:20421693

Adam-Vizi, Vera; Starkov, Anatoly A

2010-01-01

322

Non-canonical ?-catenin degradation mediates reactive oxygen species-induced epidermal cell death  

PubMed Central

?-catenin is constantly degraded through the ubiquitin-proteasomal pathway. We here report that a different type of ?-catenin degradation is causally involved in epidermal cell death. We observed that reactive oxygen species (ROS) caused ?-catenin degradation in the epidermal cells through a caspase-dependent mechanism, which results in disruption of cell adhesion. Disruption of cell adhesion increased ROS and activated caspases. Upregulation of the intact ?-catenin blocked ROS accumulation and caspase activation. These results indicate that a feed-forward loop consisting of ROS, caspases activation and ?-catenin degradation induces epidermal cell death.

Omori, Emily; Matsumoto, Kunihiro; Ninomiya-Tsuji, Jun

2011-01-01

323

Activity of artichoke leaf extract on reactive oxygen species in human leukocytes.  

PubMed

Artichoke leaf extract was studied in human leukocytes for activity against oxidative stress using flow cytometry and dichlorofluorescin diacetate as a fluorescence probe. It produces a concentration-dependent inhibition of oxidative stress when cells are stimulated with agents that generate reactive oxygen species (ROS): hydrogen peroxide, phorbol-12-myristate-13-acetate (PMA), and N-formyl-methionyl-leucyl-phenylalanine (FMLP). Cynarin, caffeic acid, chlorogenic acid, and luteolin, constituents of artichoke leaf extract, also show a concentration-dependent inhibitory activity in the above models, contributing to the antioxidant activity of the extract in human neutrophils. PMID:11200096

Pérez-García, F; Adzet, T; Cañigueral, S

2000-11-01

324

Calcium and Mitochondrial Reactive Oxygen Species Generation: How to Read the Facts  

PubMed Central

A number of recent discoveries indicate that abnormal Ca2+ signaling, oxidative stress, and mitochondrial dysfunction are involved in the neuronal damage in Alzheimer’s disease. However, the literature on the interactions between these factors is controversial especially in the interpretation of the cause-effect relationship between mitochondrial damage induced by Ca2+ overload and the production of reactive oxygen species (ROS). In this review, we survey the experimental observations on the Ca2+-induced mitochondrial ROS production, explain the sources of controversy in interpreting these results, and discuss the different molecular mechanisms underlying the effect of Ca2+ on the ROS emission by brain mitochondria.

Adam-Vizi, Vera; Starkov, Anatoly A.

2011-01-01

325

Effect of CO 2 supply on formation of reactive oxygen species in Arabidopsis thaliana  

Microsoft Academic Search

Summary.  Light-induced generation of reactive oxygen species (ROS) in 2-week-old leaves of Arabidopsis thaliana was studied by means of the ROS-sensitive dyes nitroblue tetrazolium (NBT) and 5-(and-6)-carboxy-2?,7?-dichlorodihydrofluorescein\\u000a diacetate (DCF-DA). Superposition of pictures of chlorophyll fluorescence and DCF fluorescence indicated that the origin of\\u000a ROS was in the chloroplasts. Experiments were done with zero, 0.1, or 10 mM NaHCO3 in the infiltration

A. Hoffmann; E. Hammes; C. Plieth; C. Desel; B. Sattelmacher; U.-P. Hansen

2005-01-01

326

[Cellular sources of reactive oxygen and nitrogen species. Roles in signal transcription pathways].  

PubMed

The history of studies regarding reactive oxygen and nitrogen species (ROS/RNS) is approximatively of 50 years. ROS were shown initially for their deleterious effects on marcormolecules such as DNA and proteins, leading to deterioration of cellular functions as an oxidative stress. On the other hand, recent studies have demonstrated that ROS/RNS act as oxidative signalling in cells, resulting in various gene expressions. This brief review focuses on the main cellular origins of ERO/ERN, such as mitochondrial respiratory chain, NAD(P)H oxidase and NO synthases, and describe the modulation by the reactive species of two major signal transduction pathways, NF-KB and AP-1 pathways. PMID:17119466

Beaudeux, J-L; Peynet, J; Bonnefont-Rousselot, D; Therond, P; Delattre, J; Legrand, A

2006-11-01

327

Effects of fatty acids, nucleotides and reactive oxygen species on durum wheat mitochondria.  

PubMed

Linoleic acid (LA) and other fatty acids added to respiring durum wheat mitochondria (DWM) were found to cause a remarkable membrane potential (deltaPsi) decrease, as monitored by measuring safranin fluorescence. The rate of deltaPsi decrease showed (i) saturation dependence on LA concentration; (ii) fatty acid specificity; (iii) inhibition by externally added ATP, GDP, GTP and Mg(2+) and (iv) sigmoid dependence upon initial DeltaPsi, thus suggesting the existence of an active plant mitochondrial uncoupling protein (PUMP) in mitochondria from monocotyledonous species (durum wheat, Triticum durum Desf.). Surprisingly, the rate of the linoleate dependent DeltaPsi decrease was found to be activated by reactive oxygen species (ROS) (hydrogen peroxide and superoxide anion) and, moreover, linoleate proved to lower the mitochondrial generation of superoxide anion. These results suggest that ROS can activate PUMP, thus protecting the cell against mitochondrial ROS production. PMID:10722851

Pastore, D; Fratianni, A; Di Pede, S; Passarella, S

2000-03-17

328

Redox and Reactive Oxygen Species Regulation of Mitochondrial Cytochrome c Oxidase Biogenesis.  

PubMed

Abstract Significance: Cytochrome c oxidase (COX), the last enzyme of the mitochondrial respiratory chain, is the major oxygen consumer enzyme in the cell. COX biogenesis involves several redox-regulated steps. The process is highly regulated to prevent the formation of pro-oxidant intermediates. Recent Advances: Regulation of COX assembly involves several reactive oxygen species and redox-regulated steps. These include: (i) Intricate redox-controlled machineries coordinate the expression of COX isoenzymes depending on the environmental oxygen concentration. (ii) COX is a heme A-copper metalloenzyme. COX copper metallation involves the copper chaperone Cox17 and several other recently described cysteine-rich proteins, which are oxidatively folded in the mitochondrial intermembrane space. Copper transfer to COX subunits 1 and 2 requires concomitant transfer of redox power. (iii) To avoid the accumulation of reactive assembly intermediates, COX is regulated at the translational level to minimize synthesis of the heme A-containing Cox1 subunit when assembly is impaired. Critical Issues: An increasing number of regulatory pathways converge to facilitate efficient COX assembly, thus preventing oxidative stress. Future Directions: Here we will review on the redox-regulated COX biogenesis steps and will discuss their physiological relevance. Forthcoming insights into the precise regulation of mitochondrial COX biogenesis in normal and stress conditions will likely open future perspectives for understanding mitochondrial redox regulation and prevention of oxidative stress. Antioxid. Redox Signal. 00, 000-000. PMID:22937827

Bourens, Myriam; Fontanesi, Flavia; Soto, Iliana C; Liu, Jingjing; Barrientos, Antoni

2012-10-15

329

Light-responsive polymer nanoreactors: a source of reactive oxygen species on demand  

NASA Astrophysics Data System (ADS)

Various domains present the challenges of responding to stimuli in a specific manner, with the desired sensitivity or functionality, and only when required. Stimuli-responsive systems that are appropriately designed can effectively meet these challenges. Here, we introduce nanoreactors that encapsulate photosensitizer-protein conjugates in polymer vesicles as a source of ``on demand'' reactive oxygen species. Vesicles made of poly(2-methyloxazoline)-poly(dimethylsiloxane)-poly(2-methyloxazoline) successfully encapsulated the photosensitizer Rose Bengal-bovine serum albumin conjugate (RB-BSA) during a self-assembly process, as demonstrated by UV-Vis spectroscopy. A combination of light scattering and transmission electron microscopy indicated that the nanoreactors are stable over time. They serve a dual role: protecting the photosensitizer in the inner cavity and producing in situ reactive oxygen species (ROS) upon irradiation with appropriate electromagnetic radiation. Illumination with appropriate wavelength light allows us to switch on/off and to control the production of ROS. Because of the oxygen-permeable nature of the polymer membrane of vesicles, ROS escape into the environment around vesicles, as established by electron paramagnetic resonance. The light-sensitive nanoreactor is taken up by HeLa cells in a Trojan horse fashion: it is nontoxic and, when irradiated with the appropriate laser light, produces ROS that induce cell death in a precise area corresponding to the irradiation zone. These nanoreactors can be used in theranostic approaches because they can be detected via the fluorescent photosensitizer signal and simultaneously produce ROS efficiently ``on demand''.Various domains present the challenges of responding to stimuli in a specific manner, with the desired sensitivity or functionality, and only when required. Stimuli-responsive systems that are appropriately designed can effectively meet these challenges. Here, we introduce nanoreactors that encapsulate photosensitizer-protein conjugates in polymer vesicles as a source of ``on demand'' reactive oxygen species. Vesicles made of poly(2-methyloxazoline)-poly(dimethylsiloxane)-poly(2-methyloxazoline) successfully encapsulated the photosensitizer Rose Bengal-bovine serum albumin conjugate (RB-BSA) during a self-assembly process, as demonstrated by UV-Vis spectroscopy. A combination of light scattering and transmission electron microscopy indicated that the nanoreactors are stable over time. They serve a dual role: protecting the photosensitizer in the inner cavity and producing in situ reactive oxygen species (ROS) upon irradiation with appropriate electromagnetic radiation. Illumination with appropriate wavelength light allows us to switch on/off and to control the production of ROS. Because of the oxygen-permeable nature of the polymer membrane of vesicles, ROS escape into the environment around vesicles, as established by electron paramagnetic resonance. The light-sensitive nanoreactor is taken up by HeLa cells in a Trojan horse fashion: it is nontoxic and, when irradiated with the appropriate laser light, produces ROS that induce cell death in a precise area corresponding to the irradiation zone. These nanoreactors can be used in theranostic approaches because they can be detected via the fluorescent photosensitizer signal and simultaneously produce ROS efficiently ``on demand''. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr32380j

Baumann, Patric; Balasubramanian, Vimalkumar; Onaca-Fischer, Ozana; Sienkiewicz, Andrzej; Palivan, Cornelia G.

2012-12-01

330

Hypoxia induces Kv channel current inhibition by increased NADPH oxidase-derived reactive oxygen species.  

PubMed

There is current discussion whether reactive oxygen species are up- or downregulated in the pulmonary circulation during hypoxia, from which sources (i.e., mitochondria or NADPH oxidases) they are derived, and what the downstream targets of ROS are. We recently showed that the NADPH oxidase homolog NOX4 is upregulated in hypoxia-induced pulmonary hypertension in mice and contributes to the vascular remodeling in pulmonary hypertension. We here tested the hypothesis that NOX4 regulates K(v) channels via an increased ROS formation after prolonged hypoxia. We showed that (1) NOX4 is upregulated in hypoxia-induced pulmonary hypertension in rats and isolated rat pulmonary arterial smooth muscle cells (PASMC) after 3days of hypoxia, and (2) that NOX4 is a major contributor to increased reactive oxygen species (ROS) after hypoxia. Our data indicate colocalization of K(v)1.5 and NOX4 in isolated PASMC. The NADPH oxidase inhibitor and ROS scavenger apocynin as well as NOX4 siRNA reversed the hypoxia-induced decrease in K(v) current density whereas the protein levels of the channels remain unaffected by siNOX4 treatment. Determination of cysteine oxidation revealed increased NOX4-mediated K(v)1.5 channel oxidation. We conclude that sustained hypoxia decreases K(v) channel currents by a direct effect of a NOX4-derived increase in ROS. PMID:22222468

Mittal, Manish; Gu, Xiang Q; Pak, Oleg; Pamenter, Matthew E; Haag, Daniela; Fuchs, D Beate; Schermuly, Ralph T; Ghofrani, H A; Brandes, Ralf P; Seeger, Werner; Grimminger, Friedrich; Haddad, Gabriel G; Weissmann, Norbert

2011-12-16

331

Formation of reactive oxygen species in rat epithelial cells upon stimulation with fly ash.  

PubMed

Fly ash was used as a model for ambient particulate matter which is under suspicion to cause adverse pulmonary health effects. The fly ash was pre-sized and contained only particles < 20 microm including an ultrafine fraction (< 100 nm) that contributed 31% to the particle number. In our study, we investigated the influence of fly ash on the promotion of early inflammatory reactions like the formation of reactive oxygen species (ROS) in rat lung epithelial cells (RLE-6TN). Furthermore, we determined the formation of nitric oxide (NO). The cells show a clear dose-response relationship concerning the formation of ROS with regard to the mass of particles applied. Lipopolysaccharide (LPS) added as a co-stimulus did not increase the formation of ROS induced by fly ash. Furthermore, in LPS (0.1 microg/ml) and tumour necrosis factor-alpha (TNF-alpha; 1 ng/ml) pre-treated cells no increase in reactive oxygen species comparable to fly ash alone is observable. In presence of the metal chelator, desferrioxamine (DFO), ROS formation can be significantly reduced. Neither fly ash nor LPS induced a significant NO release in RLE-6TN cells. PMID:12682424

Voelkel, K; Krug, H F; Diabaté, S

2003-02-01

332

Protective activity of propofol, Diprivan and intralipid against active oxygen species.  

PubMed Central

We separately studied the antioxidant properties of propofol (PPF), Diprivan (the commercial form of PPF) and intralipid (IL) (the vehicle solution of PPF in Diprivan) on active oxygen species produced by phorbol myristate acetate (10(-6) M)-stimulated human polymorphonuclear leukocytes (PMN: 5 x 10(5) cells/assay), human endothelial cells (5 x 10(5) cells/assay) or cell-free systems (NaOCl or H2O2/peroxidase systems), using luminol (10(-4) M)-enhanced chemiluminescence (CL). We also studied the protective effects of Diprivan on endothelial cells submitted to an oxidant stress induced by H2O2/MPO system: cytotoxicity was assessed by the release of preincorporated 51Cr. Propofol inhibited the CL produced by stimulated PMN in a dose dependent manner (until 5 x 10(-5) M, a clinically relevant concentration), while Diprivan and IL were not dose-dependent inhibitors. The CL produced by endothelial cells was dose-dependently inhibited by Diprivan and PPF, and weakly by IL (not dose-dependent). In cell free systems, dose-dependent inhibitions were obtained for the three products with a lower effect for IL. Diprivan efficaciously protected endothelial cells submitted to an oxidant stress, while IL was ineffective. By HPLC, we demonstrated that PPF was not incorporated into the cells. The drug thus acted by scavenging the active oxygen species released in the extracellular medium. IL acted in the same manner, but was a less powerful antioxidant.

Mathy-Hartert, M; Deby-Dupont, G; Hans, P; Deby, C; Lamy, M

1998-01-01

333

Bridelia ferruginea promotes reactive oxygen species detoxification in N-nitrosodiethylamine-treated rats.  

PubMed

This study was aimed at investigating the in vitro and in vivo reactive oxygen species (ROS) scavenging and detoxification potentials of aqueous extract of Bridelia ferruginea (B. ferruginea). Reactive oxygen species scavenging potentials of the aqueous leaf extract of B. ferruginea (0.2-1.0 mg/ml) was investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide ion, hydrogen peroxide, hydroxyl radical, and ferric ion reducing system. The detoxification of ROS was evaluated in N-nitrosodiethylamine-induced redox imbalance in the liver of rats. B. ferruginea extract at 1.0 mg/ml scavenged the DPPH, superoxide ion, hydrogen peroxide, and hydroxyl radical at 87%, 83%, 92%, and 86%, respectively, it also reduced ferric ion significantly. ROS detoxifying enzymes (superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase, and glucose 6-phosphate dehydrogenase) activities were significantly (p < .05) induced by B. ferruginea. These inductions significantly (p < .05) attenuated the N-nitrosodiethylamine-mediated decrease in ROS detoxifying enzymes and compared favorably with Vitamin C. N-nitrosodiethylamine-mediated elevation in the concentrations of malondialdehyde, conjugated dienes, lipid hydroperoxides, protein carbonyl, and percentage DNA fragmentation were significantly (p < .05) lowered by B. ferruginea extract. Overall, the results of this study show that B. ferruginea leaf extract possess ROS scavenging and detoxification potentials. PMID:23927656

Ajiboye, T O; Abdussalam, F A; Adeleye, A O; Iliasu, G A; Ariyo, F A; Adediran, Z A; Raji, K O; Raji, H O

2013-08-09

334

A Novel Function for Hydroxyproline Oxidase in Apoptosis through Generation of Reactive Oxygen Species*  

PubMed Central

Proline and hydroxyproline are metabolized by distinct pathways. Proline is important for protein synthesis, as a source of glutamate, arginine, and tricarboxylic acid cycle intermediates, and for participating in a metabolic cycle that shuttles redox equivalents between mitochondria and cytosol. Hydroxyproline, in contrast, is not reutilized for protein synthesis. The first steps in the degradation of proline and hydroxyproline are catalyzed by proline oxidase (POX) and hydroxyproline oxidase (OH-POX), respectively. Because it is well documented that POX is induced by p53 and plays a role in apoptosis, we considered whether OH-POX also participates in the response to cytotoxic stress. In LoVo and RKO cells, which respond to adriamycin with a p53-mediated induction of POX and generation of reactive oxygen species, we found that adriamycin also induced OH-POX gene expression and markedly increased OH-POX catalytic activity, and this increase in activity was not observed in the cell lines HT29 and HCT15, which do not have a functional p53. We also observed an increase in reactive oxygen species generation and activation of caspase-9 with adriamycin in a hydroxyproline-dependent manner. Therefore, we hypothesize that OH-POX plays a role analogous to POX in growth regulation, ROS generation, and activation of the apoptotic cascade.

Cooper, Sandra K.; Pandhare, Jui; Donald, Steven P.; Phang, James M.

2008-01-01

335

Snail-Mediated Regulation of Reactive Oxygen Species in ARCaP Human Prostate Cancer Cells  

PubMed Central

Reactive oxygen species increases in various diseases including cancer and has been associated with induction of epithelial-mesenchymal transition (EMT), as evidenced by decrease in cell adhesion-associated molecules like E-cadherin, and increase in mesenchymal markers like vimentin. We investigated the molecular mechanisms by which Snail transcription factor, an inducer of EMT, promotes tumor aggressiveness utilizing ARCaP prostate cancer cell line. An EMT model created by Snail overexpression in ARCaP cells was associated with decreased E-cadherin and increased vimentin. Moreover, Snail-expressing cells displayed increased concentration of reactive oxygen species (ROS), specifically, superoxide and hydrogen peroxide, in vitro and in vivo. Real time PCR profiling demonstrated increased expression of oxidative stress-responsive genes, such as aldeyhyde oxidase I, in response to Snail. The ROS scavenger, N-acetyl cysteine partially reversed Snail-mediated EMT after 7 days characterized by increased E-cadherin levels and decreased ERK activity, while treatment with the MEK inhibitor, UO126, resulted in a more marked effect by 3 days, characterized by cells returning back to the epithelial morphology and increased E-cadherin. In conclusion, this study shows for the first time that Snail transcription factor can regulate oxidative stress enzymes and increase ROS-mediated EMT regulated in part by ERK activation. Therefore, Snail may be an attractive molecule for therapeutic targeting to prevent tumor progression in human prostate cancer.

Barnett, Petrina; Arnold, Rebecca S.; Mezencev, Roman; Chung, Leland W. K.; Zayzafoon, Majd; Odero-Marah, Valerie

2010-01-01

336

Methionine oxidation by peroxymonocarbonate, a reactive oxygen species formed from CO2/bicarbonate and hydrogen peroxide.  

PubMed

Kinetic and thermodynamic evidence is reported for the role of the peroxymonocarbonate ion, HCO4-, as a reactive oxygen species in biology. Peroxymonocarbonate results from the equilibrium reaction of hydrogen peroxide with bicarbonate via the perhydration of CO2. The kinetic parameters for HCO4- oxidation of free methionine have been obtained (k1 = 0.48 +/- 0.08 M(-1)s(-1) by a spectrophotometric initial rate method). At the physiological concentration of bicarbonate in blood ( approximately 25 mM), it is estimated that peroxymonocarbonate formed in equilibrium with hydrogen peroxide will oxidize methionine approximately 2-fold more rapidly than plasma H2O2 itself. As an example of methionine oxidation in proteins, the bicarbonate-catalyzed hydrogen peroxide oxidation of alpha1-proteinase inhibitor (alpha1-PI) has been investigated via its inhibitory effect on porcine pancreatic elastase activity. The second-order rate constant for HCO4- oxidation of alpha1-PI (0.36 +/- 0.06 M(-1)s(-1)) is comparable to that of free methionine, suggesting that methionine oxidation is occurring. Further evidence for methionine oxidation, specifically involving Met358 and Met351 of the alpha1-PI reactive center loop, has been obtained through amino acid analyses and mass spectroscopic analyses of proteolytic digests of the oxidized alpha1-PI. These results strongly suggest that HCO4- should be considered a reactive oxygen species in aerobic metabolism. PMID:14680677

Richardson, David E; Regino, Celeste A S; Yao, Huirong; Johnson, Jodie V

2003-12-15

337

Pyrene-stimulated reactive oxygen species generation and oxidative damage in Carassius auratus.  

PubMed

Laboratory experiments were carried out to understand the toxicology of pyrene in the goldfish Carassius auratus and investigate the potential oxidative stress induced by reactive oxygen species (ROS) in vivo in a time-dependent manner. Pyrene bioaccumulation, induction of reactive oxygen species and the consequent biochemical responses in the liver of the fish were examined. Fish were exposed to 0.05 mg/L pyrene for different periods. The pyrene concentration in fish liver was analyzed by high performance liquid chromatography (HPLC). Free radicals were detected by electron paramagnetic resonance (EPR). The activities of antioxidant enzymes, contents of nonenzymatic antioxidants and malondialdehyde (MDA) in fish liver were also determined. Results indicated that the pyrene concentrations in fish liver reached a maximum level on day 1, and then declined to a low steady state level over 7 days. The free radical significantly increased at 6 h and reached a maximum on day 2, while the superoxide dismutase (SOD) activity and MDA content were induced, and the reduced glutathione (GSH) content was inhibited by day 2. The catalase (CAT) and glutathione-S-transferase (GST) activities were significantly induced at 12 h. These results indicated that pyrene was rapidly bioaccumulated in fish resulting in redox cycling, and the production of free radical is an important mechanism of pyrene toxicity in C. auratus. The indicators of antioxidant system are sensitive and useful for the study of early biomarkers of pyrene exposure in fish. PMID:24171415

Yin, Ying; Jia, Jun; Guo, Hong Y; Yang, Liu Y; Wang, Xiao R; Sun, Yuan Y

2014-01-01

338

Advanced glycation end products enhance reactive oxygen and nitrogen species generation in neutrophils in vitro.  

PubMed

Increased oxidative stress (OS) in diabetes mellitus is one of the major factors leading to diabetic pathology. However, the mediators and mechanism that provoke OS in diabetes is not fully understood, and it is possible that accumulation of advanced glycation end products (AGEs) formed secondary to hyperglycemic conditions may incite circulating polymorphonuclear neutrophils (PMN) to generate reactive oxygen species (ROS). In this report, we aim to investigate the effect of AGE on reactive oxygen and nitrogen species generation and subsequent OS in PMN. AGE-HSA exert dose- and time-dependent enhancement of ROS and reactive nitrogen intermediates (RNI) generation by PMN. Increased ROS and RNI generation were found to be mediated through the upregulation of NADPH oxidase and inducible nitric oxide synthase (iNOS), respectively, as evident from the fact that AGE-treated neutrophils failed to generate ROS and RNI in presence of diphenyleneiodonium, a flavoprotein inhibitor for both enzymes. Further increased generation of ROS and RNI ceased when the cells were incubated with anti-RAGE antibody suggesting the involvement of AGE-RAGE interaction. Also increased malondialdehyde (MDA) and protein carbonyl formation in AGE-exposed PMN suggest induction of OS by AGE. This study provides evidence that AGEs may play a key role in the induction of oxidative stress through the augmentation of PMN-mediated ROS and RNI generation and this may be in part responsible for development of AGE-induced diabetic pathology. PMID:22048812

Bansal, Savita; Siddarth, Manushi; Chawla, Diwesh; Banerjee, Basu D; Madhu, S V; Tripathi, Ashok K

2011-11-03

339

Involvement of Reactive Oxygen Species in Sonodynamically Induced Apoptosis Using a Novel Porphyrin Derivative  

PubMed Central

In this study, we investigated the induction of apoptosis by ultrasound in the presence of the novel porphyrin derivative DCPH-P-Na(I). HL-60 cells were exposed to ultrasound for up to 3 min in the presence and absence of DCPH-P-Na(I), and the induction of apoptosis was examined by analyzing cell morphology, DNA fragmentation, and caspase-3 activity. Reactive oxygen species were measured by means of ESR and spin trapping technique. Cells treated with 8 ?M DCPH-P-Na(I) and ultrasound clearly showed membrane blebbing and cell shrinkage, whereas significant morphologic changes were not observed in cells exposed to either ultrasound or DCPH-P-Na(I) alone. Also, DNA ladder formation and caspase-3 activation were observed in cells treated with both ultrasound and DCPH-P-Na(I) but not in cells treated with ultrasound or DCPH-P-Na(I) alone. In addition, the combination of DCPH-P-Na(I) and the same acoustical arrangement of ultrasound substantially enhanced nitroxide generation by the cells. Sonodynamically induced apoptosis, caspase-3 activation, and nitroxide generation were significantly suppressed by histidine. These results indicate that the combination of ultrasound and DCPH-P-Na(I) induced apoptosis in HL-60 cells. The significant reduction in sonodynamically induced apoptosis, nitroxide generation, and caspase-3 activation by histidine suggests active species such as singlet oxygen are important in the sonodynamic induction of apoptosis. These experimental results support the possibility of sonodynamic treatment for cancer using the induction of apoptosis.

Yumita, Nagahiko; Iwase, Yumiko; Nishi, Koji; Komatsu, Hajime; Takeda, Kazuyoshi; Onodera, Kenji; Fukai, Toshio; Ikeda, Toshihiko; Umemura, Shin-ichiro; Okudaira, Kazuho; Momose, Yasunori

2012-01-01

340

Overexpression of stanniocalcin-1 inhibits reactive oxygen species and renal ischemia/reperfusion injury in mice  

PubMed Central

Reactive oxygen species, endothelial dysfunction, inflammation, and mitogen-activated protein kinases have important roles in the pathogenesis of ischemia/reperfusion kidney injury. Stanniocalcin-1 (STC1) suppresses superoxide generation in many systems through induction of mitochondrial uncoupling proteins and blocks the cytokine-induced rise in endothelial permeability. Here we tested whether transgenic overexpression of STC1 protects from bilateral ischemia/reperfusion kidney injury. This injury in wild type mice caused a halving of the creatinine clearance; severe tubular vacuolization and cast formation; increased infiltration of macrophages and T cells; higher vascular permeability; greater production of superoxide and hydrogen peroxide; and higher ratio of activated ERK/activated JNK and p38, all compared to sham-treated controls. Mice transgenic for human STC1 expression, however, had resistance to equivalent ischemia/reperfusion injury indicated as no significant change from controls in any of these parameters. Tubular epithelial cells in transgenic mice expressed higher mitochondrial uncoupling protein 2 and lower superoxide generation. Pre-treatment of transgenic mice with paraquat, a generator of reactive oxygen species, before injury restored the susceptibility to ischemia/reperfusion kidney injury, suggesting that STC1 protects by an anti-oxidant mechanism. Thus, STC1 may be a therapeutic target for ischemia/reperfusion kidney injury.

Huang, Luping; Belousova, Tatiana; Chen, Minyi; DiMattia, Gabriel; Liu, Dajun; Sheikh-Hamad, David

2012-01-01

341

The chemistry of cell signaling by reactive oxygen and nitrogen species and 4-hydroxynonenal  

PubMed Central

During the past several years, major advances have been made in understanding how reactive oxygen species (ROS) and nitrogen species (RNS) participate in signal transduction. Identification of the specific targets and the chemical reactions involved still remains to be resolved with many of the signaling pathways in which the involvement of reactive species has been determined. Our understanding is that ROS and RNS have second messenger roles. While cysteine residues in the thiolate (ionized) form found in several classes of signaling proteins can be specific targets for reaction with H2O2 and RNS, better understanding of the chemistry, particularly kinetics, suggests that for many signaling events in which ROS and RNS participate, enzymatic catalysis is more likely to be involved than non-enzymatic reaction. Due to increased interest in how oxidation products, particularly lipid peroxidation products, also are involved with signaling, a review of signaling by 4-hydroxy-2-nonenal (HNE) is included. This article focuses on the chemistry of signaling by ROS, RNS, and HNE and will describe reactions with selected target proteins as representatives of the mechanisms rather attempt to comprehensively review the many signaling pathways in which the reactive species are involved.

Forman, Henry Jay; Fukuto, Jon M.; Miller, Tom; Zhang, Hongqiao; Rinna, Alessandra; Levy, Smadar

2008-01-01

342

Oxidative stress and protection against reactive oxygen species in the pre-implantation embryo and its surroundings  

Microsoft Academic Search

Oxidative stress is involved in the aetiology of defective embryo development. Reactive oxygen species (ROS) may originate from embryo metabolism and\\/or embryo surroundings. Embryo metabolism generates ROS via several enzymatic mechanisms. The relative contribution of each source seems different depending on the species, the stage of development, and the culture conditions. Several exogenous factors and culture conditions can enhance the

P. Guerin; S. El Mouatassim; Y. Menezo

2001-01-01

343

Metabolism of reactive oxygen species and reactive nitrogen species in pepper (Capsicum annuum L.) plants under low temperature stress.  

PubMed

Low temperature is an environmental stress that affects crop production and quality and regulates the expression of many genes, and the level of a number of proteins and metabolites. Using leaves from pepper (Capsicum annum L.) plants exposed to low temperature (8 °C) for different time periods (1 to 3 d), several key components of the metabolism of reactive nitrogen and oxygen species (RNS and ROS, respectively) were analysed. After 24 h of exposure at 8 °C, pepper plants exhibited visible symptoms characterized by flaccidity of stems and leaves. This was accompanied by significant changes in the metabolism of RNS and ROS with an increase of both protein tyrosine nitration (NO(2) -Tyr) and lipid peroxidation, indicating that low temperature induces nitrosative and oxidative stress. During the second and third days at low temperature, pepper plants underwent cold acclimation by adjusting their antioxidant metabolism and reverting the observed nitrosative and oxidative stress. In this process, the levels of the soluble non-enzymatic antioxidants ascorbate and glutathione, and the activity of the main NADPH-generating dehydrogenases were significantly induced. This suggests that ascorbate, glutathione and the NADPH-generating dehydrogenases have a role in the process of cold acclimation through their effect on the redox state of the cell. PMID:21414013

Airaki, Morad; Leterrier, Marina; Mateos, Rosa M; Valderrama, Raquel; Chaki, Mounira; Barroso, Juan B; Del Río, Luis A; Palma, José M; Corpas, Francisco J

2011-04-07

344

Emission of short-chained oxygenated voc from the leaves of mature central european tree species  

NASA Astrophysics Data System (ADS)

The photolytic and oxidative destruction of volatile organic compounds (VOC) in the atmosphere results in a net production of tropospheric ozone. Oxygenated VOC (OVOC) are either directly emitted into the atmosphere or are produced there by oxidation of other hydrocarbons. Besides anthropogenic sources, the emission of OVOC by vegetation, particularly by forest ecosystems, is considered a major source of atmospheric OVOC. Exact numbers on emission rates from important tree species as well as production mechanisms that lead to the release of OVOC from leaves are, however, not known. In the present study, field campaigns were conducted in typical forest ecosystems in Germany in order to elucidate the spectrum and the amount of OVOC emitted by Central European tree species. Exchange data obtained were compared with physiological and meteorological parameters to obtain information on the factors controlling trace gas exchange. The field campaigns were accompanied by studies under controlled conditions in the laboratory. The poster presents data on carbonyl exchange between Picea abies, Fagus sylvatica, Carpinus betulus and other species and the atmosphere and indicates plant internal and meteorological factors (temperature, ambient OVOC concentrations, light intensities, water supply, etc.) that may determine exchange rates.

Kreuzwieser, J.; Cojocariu, C.; Rennenberg, H.

2003-04-01

345

Chemical kinetics and reactive species in atmospheric pressure helium-oxygen plasmas with humid-air impurities  

NASA Astrophysics Data System (ADS)

In most applications helium-based plasma jets operate in an open-air environment. The presence of humid air in the plasma jet will influence the plasma chemistry and can lead to the production of a broader range of reactive species. We explore the influence of humid air on the reactive species in radio frequency (rf)-driven atmospheric-pressure helium-oxygen mixture plasmas (He-O2, helium with 5000 ppm admixture of oxygen) for wide air impurity levels of 0-500 ppm with relative humidities of from 0% to 100% using a zero-dimensional, time-dependent global model. Comparisons are made with experimental measurements in an rf-driven micro-scale atmospheric pressure plasma jet and with one-dimensional semi-kinetic simulations of the same plasma jet. These suggest that the plausible air impurity level is not more than hundreds of ppm in such systems. The evolution of species concentration is described for reactive oxygen species, metastable species, radical species and positively and negatively charged ions (and their clusters). Effects of the air impurity containing water humidity on electronegativity and overall plasma reactivity are clarified with particular emphasis on reactive oxygen species.

Murakami, Tomoyuki; Niemi, Kari; Gans, Timo; O'Connell, Deborah; Graham, William G.

2013-02-01

346

Protective effect of flavonoids against reactive oxygen species production in sickle cell anemia patients treated with hydroxyurea  

PubMed Central

Objective The aim of this study was to evaluate the protective effects of quercetin, rutin, hesperidin and myricetin against reactive oxygen species production with the oxidizing action of tert-butylhydroperoxide in erythrocytes from normal subjects and sickle cell anemia carriers treated with hydroxyurea. Methods Detection of intracellular reactive oxygen species was carried out using a liposoluble probe, 2',7'-dichlorfluorescein-diacetate (DCFH-DA). A 10% erythrocyte suspension was incubated with flavonoids (quercetin, rutin, hesperidin or myricetin; 30, 50, and 100 µmol/L), and then incubated with tert-butylhydroperoxide (75 µmol/L). Untreated samples were used as controls. Results Red blood cell exposure to tert-butylhydroperoxide resulted in significant increases in the generation of intracellular reactive oxygen species compared to basal levels. Reactive oxygen species production was significantly inhibited when red blood cells were pre-incubated with flavonoids, both in normal individuals and in patients with sickle cell anemia. Quercetin and rutin had the highest antioxidant activity, followed by myricetin and hesperidin. CONCLUSION: Flavonoids, in particular quercetin and rutin, showed better antioxidant effects against damage caused by excess reactive oxygen species characteristic of sickle cell anemia. Results obtained with patients under treatment with hydroxyurea suggest an additional protective effect when associated with the use of flavonoids.

Henneberg, Railson; Otuki, Michel Fleith; Furman, Aline Emmer Ferreira; Hermann, Priscila; do Nascimento, Aguinaldo Jose; Leonart, Maria Suely Soares

2013-01-01

347

Cross-talk of nitric oxide and reactive oxygen species in plant programed cell death  

PubMed Central

In plants, programed cell death (PCD) is an important mechanism to regulate multiple aspects of growth and development, as well as to remove damaged or infected cells during responses to environmental stresses and pathogen attacks. Under biotic and abiotic stresses, plant cells exhibit a rapid synthesis of nitric oxide (NO) and a parallel accumulation of reactive oxygen species (ROS). Frequently, these responses trigger a PCD process leading to an intrinsic execution of plant cells. The accumulating evidence suggests that both NO and ROS play key roles in PCD. These redox active small molecules can trigger cell death either independently or synergistically. Here we summarize the recent progress on the cross-talk of NO and ROS signals in the hypersensitive response, leaf senescence, and other kinds of plant PCD caused by diverse cues.

Wang, Yiqin; Loake, Gary J.; Chu, Chengcai

2013-01-01

348

Atrial fibrillation in the elderly: the potential contribution of reactive oxygen species.  

PubMed

Atrial fibrillation (AF) is the most commonly encountered cardiac arrhythmia, and is a significant source of healthcare expenditures throughout the world. It is an arrhythmia with a very clearly defined predisposition for individuals of advanced age, and this fact has led to intense study of the mechanistic links between aging and AF. By promoting oxidative damage to multiple subcellular and cellular structures, reactive oxygen species (ROS) have been shown to induce the intra- and extra-cellular changes necessary to promote the pathogenesis of AF. In addition, the generation and accumulation of ROS have been intimately linked to the cellular processes which underlie aging. This review begins with an overview of AF pathophysiology, and introduces the critical structures which, when damaged, predispose an otherwise healthy atrium to AF. The available evidence that ROS can lead to damage of these critical structures is then reviewed. Finally, the evidence linking the process of aging to the pathogenesis of AF is discussed. PMID:23341843

Schillinger, Kurt J; Patel, Vickas V

2012-12-01

349

The antimicrobial peptide, psacotheasin induces reactive oxygen species and triggers apoptosis in Candida albicans.  

PubMed

Previously, the antimicrobial effects and membrane-active action of psacotheasin in Candida albicans were investigated. In this study, we have further found that a series of characteristic cellular changes of apoptosis in C. albicans can be induced by the accumulation of intracellular reactive oxygen species, specifically hydroxyl radicals, the well-known important regulators of apoptosis. Cells treated with psacotheasin showed diagnostic markers in yeast apoptosis at early stages: phosphatidylserine externalization from the inner to the outer membrane surface, visualized by Annexin V-staining; mitochondrial membrane depolarization, observed by DiOC6(3) staining; and increase of metacaspase activity, measured using the CaspACE FITC-VAD-FMK. Moreover, DNA fragmentation and condensation also revealed apoptotic phenomena at late stages through the TUNEL assay staining and DAPI staining, respectively. Taken together, our findings suggest that psacotheasin possess an antifungal property in C. albicans via apoptosis as another mode of action. PMID:21219857

Hwang, Bomi; Hwang, Jae-Sam; Lee, Juneyoung; Lee, Dong Gun

2011-01-08

350

Atrial fibrillation in the elderly: the potential contribution of reactive oxygen species  

PubMed Central

Atrial fibrillation (AF) is the most commonly encountered cardiac arrhythmia, and is a significant source of healthcare expenditures throughout the world. It is an arrhythmia with a very clearly defined predisposition for individuals of advanced age, and this fact has led to intense study of the mechanistic links between aging and AF. By promoting oxidative damage to multiple subcellular and cellular structures, reactive oxygen species (ROS) have been shown to induce the intra- and extra-cellular changes necessary to promote the pathogenesis of AF. In addition, the generation and accumulation of ROS have been intimately linked to the cellular processes which underlie aging. This review begins with an overview of AF pathophysiology, and introduces the critical structures which, when damaged, predispose an otherwise healthy atrium to AF. The available evidence that ROS can lead to damage of these critical structures is then reviewed. Finally, the evidence linking the process of aging to the pathogenesis of AF is discussed.

Schillinger, Kurt J.; Patel, Vickas V.

2012-01-01

351

Reversible inactivation of deubiquitinases by reactive oxygen species in vitro and in cells  

PubMed Central

In eukaryotes, deubiquitinases (DUBs) remove ubiquitin conjugates from diverse substrates, altering their stabilities, localizations or activities. Here we show that many DUBs of the USP and UCH subfamilies can be reversibly inactivated upon oxidation by reactive oxygen species in vitro and in cells. Oxidation occurs preferentially on the catalytic cysteine, abrogating the isopeptide-cleaving activity without affecting these enzymes’ affinity to ubiquitin. Sensitivity to oxidative inhibition is associated with DUB activation wherein the active site cysteine is converted to a deprotonated state prone to oxidation. We demonstrate that this redox regulation is essential for mono-ubiquitination of proliferating-cell nuclear antigen in response to oxidative DNA damage, which initiates a DNA damage-tolerance programme. These findings establish a novel mechanism of DUB regulation that may be integrated with other redox-dependent signalling circuits to govern cellular adaptation to oxidative stress, a process intimately linked to aging and cancer.

Lee, Jin-Gu; Baek, Kheewoong; Soetandyo, Nia; Ye, Yihong

2013-01-01

352

Evidence that reactive oxygen species do not mediate NF-?B activation  

PubMed Central

It has been postulated that reactive oxygen species (ROS) may act as second messengers leading to nuclear factor (NF)-?B activation. This hypothesis is mainly based on the findings that N-acetyl-l-cysteine (NAC) and pyrrolidine dithiocarbamate (PDTC), compounds recognized as potential antioxidants, can inhibit NF-?B activation in a wide variety of cell types. Here we reveal that both NAC and PDTC inhibit NF-?B activation independently of antioxidative function. NAC selectively blocks tumor necrosis factor (TNF)-induced signaling by lowering the affinity of receptor to TNF. PDTC inhibits the I?B–ubiquitin ligase activity in the cell-free system where extracellular stimuli-regulated ROS production does not occur. Furthermore, we present evidence that endogenous ROS produced through Rac/NADPH oxidase do not mediate NF-?B signaling, but instead lower the magnitude of its activation.

Hayakawa, Makio; Miyashita, Hiroshi; Sakamoto, Isao; Kitagawa, Masatoshi; Tanaka, Hirofumi; Yasuda, Hideyo; Karin, Michael; Kikugawa, Kiyomi

2003-01-01

353

Reactive oxygen species inhibitors block priming, but not activation of the NLRP3 inflammasome  

PubMed Central

A common denominator among the multiple damage-inducing agents that ultimately lead to the activation of NLRP3 has not yet been identified. Recently, the production of reactive oxygen species (ROS) has been suggested to act as a common event upstream of the NLRP3 inflammasome machinery. Since de novo translation of NLRP3 is an essential step in the activation of NLRP3, we investigated the role of substances that either inhibit ROS production or its oxidative activity. While we observe that NLRP3 inflammasome activation is unique amongst other known inflammasomes due to its sensitivity to ROS inhibition, we have found that this phenomenon is attributable to the fact that NLRP3 strictly requires priming by a pro-inflammatory signal, a step that is blocked by ROS inhibitors. While these data do not exclude a general role of ROS production in the process of NLRP3-triggered inflammation, they put ROS upstream of NLRP3 induction, but not activation.

Bauernfeind, Franz; Bartok, Eva; Rieger, Anna; Franchi, Luigi; Nunez, Gabriel; Hornung, Veit

2011-01-01

354

Effects of Surface Chemistry on the Generation of Reactive Oxygen Species by Copper Nanoparticles  

PubMed Central

Mercaptocarboxylic acids with different carbon chain lengths were used for stabilizing uniform 15 nm copper nanoparticles. The effects of surface chemistry such as ligand type and surface oxidation on the reactive oxygen species (ROS) generated by the copper nanoparticles were examined. Transmission electron microscopy (TEM), Powder X-ray diffraction (PXRD), UV-vis spectroscopy, and an acellular ROS assay show that ROS generation is closely related to the surface oxidation of copper nanoparticles. It was found that the copper nanoparticles with longer chain ligands had surfaces that were better protected from oxidation and a corresponding lower ROS generating capacity than did particles with shorter chain ligands. Conversely, the copper nanoparticles with greater surface oxidation also had higher ROS generating capacity.

Shi, Miao; Kwon, Hyun Soo; Peng, Zhenmeng; Elder, Alison; Yang, Hong

2012-01-01

355

Sunscreen enhancement of UV-induced reactive oxygen species in the skin.  

PubMed

The number of UV-induced (20 mJ cm(-2)) reactive oxygen species (ROS) generated in nucleated epidermis is dependent upon the length of time the UV filter octocrylene, octylmethoxycinnamate, or benzophenone-3 remains on the skin surface. Two-photon fluorescence images acquired immediately after application of each formulation (2 mg cm(-2)) to the skin surface show that the number of ROS produced is dramatically reduced relative to the skin-UV filter control. After each UV filter remains on the skin surface for t=20 min, the number of ROS generated increases, although it remains below the number generated in the control. By t=60 min, the filters generate ROS above the control. The data show that when all three of the UV filters penetrate into the nucleated layers, the level of ROS increases above that produced naturally by epidermal chromophores under UV illumination. PMID:17015167

Hanson, Kerry M; Gratton, Enrico; Bardeen, Christopher J

2006-07-06

356

Reactive oxygen species involved in regulating fruit senescence and fungal pathogenicity.  

PubMed

Senescence is a vital aspect of fruit life cycles, and directly affects fruit quality and resistance to pathogens. Reactive oxygen species (ROS), as the primary mediators of oxidative damage in plants, are involved in senescence. Mitochondria are the main ROS and free radical source. Oxidative damage to mitochondrial proteins caused by ROS is implicated in the process of senescence, and a number of senescence-related disorders in a variety of organisms. However, the specific sites of ROS generation in mitochondria remain largely unknown. Recent discoveries have ascertained that fruit senescence is greatly related to ROS and incidental oxidative damage of mitochondrial protein. Special mitochondrial proteins involved in fruit senescence have been identified as the targets of ROS. We focus in discussion on our recent advances in exploring the mechanisms of how ROS regulate fruit senescence and fungal pathogenicity. PMID:23515879

Tian, Shiping; Qin, Guozheng; Li, Boqiang

2013-03-21

357

Early Increase of Reactive Oxygen Species in Pea Seedling Roots Under Hypergravity  

NASA Astrophysics Data System (ADS)

Early increase of intensity of peroxidation and formation of reactive oxygen species (ROS) in plant cells take place under various impacts. The ROS can act as second messengers in mechanism of cell responses (Mittler et al 2006; Jadko et al 2007). Early stages of ROS content (chemiluminescence, ChL) in pea root cells under 3, 5, 10 and 15g during centrifugation have been investigated. After 30 min of centrifugation, especially under 10 and 15g, the intensity of ChL increased and was higher on 40-50% comparing to controls. Than the ChL slowly decreased and reached the controls in 1 hour. The changes of the ChL depend on both the dose and the duration of centrifugation. The role of ROS in mechanism of cell response to hypergravity is discussed.

Jadko, Sergiy; Syvash, Alexander; Klymchuk, Dmytro

358

The role of reactive oxygen species in cell growth: lessons from root hairs.  

PubMed

Reactive oxygen species (ROS) play a diversity of roles in plants. In recent years, a role for NADPH oxidase-derived ROS during cell growth and development has been discovered in a number of plant model systems. These studies indicate that ROS are required for cell expansion during the morphogenesis of organs such as roots and leaves. Furthermore, there is evidence that ROS are required for root hair growth where they control the activity of calcium channels required for polar growth. The role of ROS in the control of root hair growth is reviewed here and results are highlighted that may provide insight into the mechanism of plant cell growth in general. PMID:16720604

Carol, Rachel J; Dolan, Liam

2006-05-23

359

Reactive oxygen species mediate dopamine-induced signaling in renal proximal tubule cells.  

PubMed

Intrarenally-produced dopamine (DA) induces a large increase in urinary sodium excretion mainly due to the inhibition of tubular sodium reabsorption. We aimed to study the participation of reactive oxygen species (ROS) in DA signaling pathway in proximal tubule cells. Our results show that DA increased ROS production in OK cells and indicate the mitochondria as the main source of ROS. DA also increased ERK1/2, superoxide dismutase (SOD) and transcription factor ?B (NF-?B) activity. These findings suggest that DA generates mitochondria-derived ROS that activate ERK1/2 and subsequently NF-?B and SOD activity at concentrations that exert a physiological regulation of renal function. PMID:23994527

Acquier, Andrea B; Mori Sequeiros García, Mercedes; Gorostizaga, Alejandra B; Paz, Cristina; Mendez, Carlos F

2013-08-28

360

Ellagic acid protects hepatocytes from damage by inhibiting mitochondrial production of reactive oxygen species.  

PubMed

The aim of this experiment is to investigate the antioxidative and antiapoptotic roles of ellagic (EA) acid in in vitro and in in vivo experiment. We measured protective properties of EA against oxidative stress-induced hepatocyte damage in vitro and Concanavalin (ConA)-induced liver damage in vivo. EA, a potent antioxidant, exhibited protective properties against oxidative stress-induced hepatocyte damage by preventing vitamin k3 (VK3)-induced reactive oxygen species (ROS) productions, apoptotic and necrotic cellular damage and mitochondrial depolarization, which is a main cause of ROS production. EA also protects against cell death and elevation of glutathione (GSH), alanine transaminase (ALT) and asparatate transaminase (AST) in Con A-induced fulminant liver damage in mice. These results show that antioxidant and cytoprotective properties of EA prevent liver damage induced by various type of oxidative stress. PMID:20347566

Hwang, Jung Me; Cho, Jin Sook; Kim, Tae Hyeon; Lee, Young Ik

2009-10-23

361

Modulation of macrophage-mediated cytotoxicity by kerosene soot: Possible role of reactive oxygen species  

SciTech Connect

The involvement of reactive oxygen species (ROS) in the cytotoxicity of soot on rat alveolar macrophages has been postulated. A single intratracheal injection of soot (5 mg) in corn oil significantly induced the macrophage population, hydrogen peroxide (H[sub 2]O[sub 2]) generation, thiobarbituric acid (TBA)-reactive substanced of lipid peroxidation, and the activities of extracellular acid phosphatase (AP) and lactate dehydrogenase (LDH) at 1, 4, 8, and 16 days of postinoculation. The activities of glutathione peroxidase (GPX) and catalase (CAT) were significantly inhibited at all the stages, while glutathione reductase (GR) and glucose-6-phosphate dehydrogenase (G6PD) showed a different pattern. These results show that soot is cytotoxic to alveolar macrophages and suggest that ROS may play a primary role in the cytotoxic process. 28 refs., 4 figs., 1 tab.

Arif, J.M.; Khan, S.G.; Ashquin, M.; Rahman, Q. (Industrial Toxicology Research Centre, Lucknow (India))

1993-05-01

362

Oxygen-derived species: their relation to human disease and environmental stress.  

PubMed Central

Free radicals and other reactive oxygen species (ROS) are constantly formed in the human body, often for useful metabolic purposes. Antioxidant defenses protect against them, but these defenses are not completely adequate, and systems that repair damage by ROS are also necessary. Mild oxidative stress often induces antioxidant defense enzymes, but severe stress can cause oxidative damage to lipids, proteins, and DNA within cells, leading to such events as DNA strand breakage and disruption of calcium ion metabolism. Oxidative stress can result from exposure to toxic agents, and by the process of tissue injury itself. Ozone, oxides of nitrogen, and cigarette smoke can cause oxidative damage; but the molecular targets that they damage may not be the same.

Halliwell, B; Cross, C E

1994-01-01

363

Caffeine protects human skin fibroblasts from acute reactive oxygen species-induced necrosis.  

PubMed

Oxidative damage by reactive oxygen species (ROS) plays a major role in aging and carcinogenesis. Little is known about either the effects of acute ROS in necrosis and inflammation of skin or the therapeutic agents for prevention and treatment. Previously, our laboratory identified caffeine as an inhibitor of hydrogen peroxide (H2O2)-generated lipid peroxidation products in human skin fibroblasts. Here, we study effects of caffeine on acute ROS-mediated necrosis. Human skin fibroblasts were incubated with caffeine, followed by H2O2 challenge. Flow cytometry was used to analyze cell morphology, counts, apoptosis and necrosis, and ROS. We found that caffeine protects from H2O2 cell damage at lower (0.01 mM) and intermediate (0.1 mM) doses. The beneficial effects of caffeine appear to be mediated by a mechanism other than antioxidant function. PMID:23135086

Silverberg, Jonathan I; Patel, Mital; Brody, Neil; Jagdeo, Jared

2012-11-01

364

A photo-triggered layered surface coating producing reactive oxygen species.  

PubMed

We report a photoactive surface coating which produces cytotoxic reactive oxygen species (ROS) upon irradiation with near infrared (NIR) light. The coating is assembled layer-by-layer, and consists of cross-linked hyaluronic acid (HA) and poly-l-lysine (PLL) modified with the photoactive molecule pheophorbide a. Pheophorbide a loading can be fine-tuned by varying the number of bilayers, yielding stable materials with the capacity to generate repeated and/or prolonged light-triggered ROS release. Light irradiation of the photoactive surface coatings provides a versatile platform for the spatiotemporal control of events at the material-tissue interface, such as bacterial colonization, platelet adhesion, and mammalian cell attachment. PMID:24074838

Gabriel, Doris; Monteiro, Isa P; Huang, David; Langer, Robert; Kohane, Daniel S

2013-09-25

365

Fundamental roles of reactive oxygen species and protective mechanisms in the female reproductive system  

PubMed Central

Controlled oxidation, such as disulfide bond formation in sperm nuclei and during ovulation, plays a fundamental role in mammalian reproduction. Excess oxidation, however, causes oxidative stress, resulting in the dysfunction of the reproductive process. Antioxidation reactions that reduce the levels of reactive oxygen species are of prime importance in reproductive systems in maintaining the quality of gametes and support reproduction. While anti-oxidative enzymes, such as superoxide dismutase and peroxidase, play a central role in eliminating oxidative stress, reduction-oxidation (redox) systems, comprised of mainly glutathione and thioredoxin, function to reduce the levels of oxidized molecules. Aldo-keto reductase, using NADPH as an electron donor, detoxifies carbonyl compounds resulting from the oxidation of lipids and proteins. Thus, many antioxidative and redox enzyme genes are expressed and aggressively protect gametes and embryos in reproductive systems.

Fujii, Junichi; Iuchi, Yoshihito; Okada, Futoshi

2005-01-01

366

Research on killing Escherichia Coli by reactive oxygen species based on strong ionization discharging plasma  

NASA Astrophysics Data System (ADS)

Reactive oxygen species solution produced by strong ionization discharging plasma was used to kill Escherichia coli by spraying. Several effect factors such as pH value, solution temperature, spraying time and exposure time were observed in this study, and their effects on killing rate of Escherichia coli were discussed and analysed. Results show that the treating efficiency of ROS solution for Escherichia coli is higher in alkaline solution than that in acid solution. The killing rate of Escherichia coli increases while the spraying time and exposure time are longer and the temperature is lower. The effects of different factors on killing rate of Escherichia coli are as follows: spraying time > pH value > exposure time > solution temperature.

Li, Y. J.; Tian, Y. P.; Li, R. H.; Gao, J. Y.; Cai, L. J.; Zhang, Z. T.

2013-03-01

367

Polyglutamine expansion inhibits respiration by increasing reactive oxygen species in isolated mitochondria  

SciTech Connect

Huntington's disease results from expansion of the polyglutamine (PolyQ) domain in the huntingtin protein. Although the cellular mechanism by which pathologic-length PolyQ protein causes neurodegeneration is unclear, mitochondria appear central in pathogenesis. We demonstrate in isolated mitochondria that pathologic-length PolyQ protein directly inhibits ADP-dependent (state 3) mitochondrial respiration. Inhibition of mitochondrial respiration by PolyQ protein is not due to reduction in the activities of electron transport chain complexes, mitochondrial ATP synthase, or the adenine nucleotide translocase. We show that pathologic-length PolyQ protein increases the production of reactive oxygen species in isolated mitochondria. Impairment of state 3 mitochondrial respiration by PolyQ protein is reversed by addition of the antioxidants N-acetyl-L-cysteine or cytochrome c. We propose a model in which pathologic-length PolyQ protein directly inhibits mitochondrial function by inducing oxidative stress.

Puranam, Kasturi L. [Deane Laboratory, Department of Medicine, Division of Neurology, Duke University Medical Center, Durham, NC 27710 (United States); Wu, Guanghong [Deane Laboratory, Department of Medicine, Division of Neurology, Duke University Medical Center, Durham, NC 27710 (United States); Strittmatter, Warren J. [Deane Laboratory, Department of Medicine, Division of Neurology, Duke University Medical Center, Durham, NC 27710 (United States); Burke, James R. [Deane Laboratory, Department of Medicine, Division of Neurology, Duke University Medical Center, Durham, NC 27710 (United States)]. E-mail: james.burke@duke.edu

2006-03-10

368

Reactive oxygen species (ROS) is not a promotor of taxol-induced cytoplasmic vacuolization  

NASA Astrophysics Data System (ADS)

we have previously reported that taxol, a potent anticancer agent, induces caspase-independent cell death and cytoplasmic vacuolization in human lung adenocarcinoma (ASTC-a-1) cells. However, the mechanisms of taxol-induced cytoplasmic vacuolization are poorly understood. Reactive oxygen species (ROS) has been reported to be involved in the taxol-induced cell death. Here, we employed confocal fluorescence microscopy imaging to explore the role of ROS in taxol-induced cytoplasmic vacuolization. We found that ROS inhibition by addition of N-acetycysteine (NAC), a total ROS scavenger, did not suppress these vacuolization but instead increased vacuolization. Take together, our results showed that ROS is not a promotor of the taxol-induced cytoplasmic vacuolization.

Sun, Qingrui; Chen, Tongsheng

2009-02-01

369

Free sphingobases induce RBOHD-dependent reactive oxygen species production in Arabidopsis leaves.  

PubMed

Sphingolipids are implied in several regulatory processes, including cell death. Levels of the free sphingobase t18:0 (phytosphingosine) increase in Arabidopsis in response to the bacterial pathogen Pseudomonas syringae. To gain information on sphingobase-induced signaling, we determined kinetics of leaf reactive oxygen species (ROS) levels and cell death in response to specific sphingobases. t18:0, d18:0 and d17:1, but not d20:0, induced ROS and cell death within 1.5-2h. Early sphingobase-induced ROS production was independent of cell death induction and required the NADPH oxidase Respiratory Burst Oxidase Homolog D (RBOHD). Specific sphingobases can therefore induce cell death and require RBOHD for early ROS induction in plants. PMID:21856300

Peer, Markus; Bach, Matthias; Mueller, Martin J; Waller, Frank

2011-08-16

370

Regulatory volume decrease in cardiomyocytes is modulated by calcium influx and reactive oxygen species.  

PubMed

We investigated the role of Ca(2+) in generating reactive oxygen species (ROS) induced by hyposmotic stress (Hypo) and its relationship to regulatory volume decrease (RVD) in cardiomyocytes. Hypo-induced increases in cytoplasmic and mitochondrial Ca(2+). Nifedipine (Nife) inhibited both Hypo-induced Ca(2+) and ROS increases. Overexpression of catalase (CAT) induced RVD and a decrease in Hypo-induced blebs. Nife prevented CAT-dependent RVD activation. These results show a dual role of Hypo-induced Ca(2+) influx in the control of cardiomyocyte viability. Hypo-induced an intracellular Ca(2+) increase which activated RVD and inhibited necrotic blebbing thus favoring cell survival, while simultaneously increasing ROS generation, which in turn inhibited RVD and induced necrosis. PMID:19818777

Rojas-Rivera, Diego; Díaz-Elizondo, Jessica; Parra, Valentina; Salas, Daniela; Contreras, Ariel; Toro, Barbra; Chiong, Mario; Olea-Azar, Claudio; Lavandero, Sergio

2009-10-09

371

Killing by bactericidal antibiotics does not depend on reactive oxygen species.  

PubMed

Bactericidal antibiotics kill by modulating their respective targets. This traditional view has been challenged by studies that propose an alternative, unified mechanism of killing, whereby toxic reactive oxygen species (ROS) are produced in the presence of antibiotics. We found no correlation between an individual cell's probability of survival in the presence of antibiotic and its level of ROS. An ROS quencher, thiourea, protected cells from antibiotics present at low concentrations, but the effect was observed under anaerobic conditions as well. There was essentially no difference in survival of bacteria treated with various antibiotics under aerobic or anaerobic conditions. This suggests that ROS do not play a role in killing of bacterial pathogens by antibiotics. PMID:23471410

Keren, Iris; Wu, Yanxia; Inocencio, Julio; Mulcahy, Lawrence R; Lewis, Kim

2013-03-01

372

Oxidation therapy: the use of a reactive oxygen species-generating enzyme system for tumour treatment.  

PubMed Central

Oxygen radicals induce cytotoxicity via a variety of mechanisms, including DNA damage, lipid peroxidation and protein oxidation. Here, we explore the use of a polyethylene glycol (PEG)-stabilised enzyme capable of producing reactive oxygen species (ROS), glucose oxidase (GO), for the purpose of harnessing the cytotoxic potential of ROS for treating solid tumours. PEG-GO (200 U), administered by two intratumoral injections 3 h apart, produced a significant growth delay in subcutaneous rat 9L gliomas as compared with control animals receiving heat-denatured PEG-GO. Rats were protected from systemic toxicity by subsequent i.v. administration of PEG-superoxide dismutase (PEG-SOD) and PEG-catalase. In vivo tumour metabolic changes, monitored using 31P magnetic resonance spectroscopy (31P-MRS) 6 h following initial administration of PEG-GO, revealed a 96 +/- 2% reduction in the ATP/Pi ratio and a 0.72 +/- 0.10 unit decline in intracellular pH. A 3-fold sensitisation of 9L glioma cells in vitro to hydrogen peroxide could be achieved by a 24 h preincubation with buthionine sulphoximine (BSO). This study suggests that oxidation therapy, the use of an intratumoral ROS-generating enzyme system for the treatment of solid tumours, is a promising area which warrants further exploration.

Ben-Yoseph, O.; Ross, B. D.

1994-01-01

373

Influenza virus M2 protein inhibits epithelial sodium channels by increasing reactive oxygen species.  

PubMed

The mechanisms by which replicating influenza viruses decrease the expression and function of amiloride-sensitive epithelial sodium channels (ENaCs) have not been elucidated. We show that expression of M2, a transmembrane influenza protein, decreases ENaC membrane levels and amiloride-sensitive currents in both Xenopus oocytes, injected with human alpha-, beta-, and gamma-ENaCs, and human airway cells (H441 and A549), which express native ENaCs. Deletion of a 10-aa region within the M2 C terminus prevented 70% of this effect. The M2 ENaC down-regulation occurred at normal pH and was prevented by MG-132, a proteasome and lysosome inhibitor. M2 had no effect on Liddle ENaCs, which have decreased affinity for Nedd4-2. H441 and A549 cells transfected with M2 showed higher levels of reactive oxygen species, as shown by the activation of redox-sensitive dyes. Pretreatment with glutathione ester, which increases intracellular reduced thiol concentrations, or protein kinase C (PKC) inhibitors prevented the deleterious effects of M2 on ENaCs. The data suggest that M2 protein increases steady-state concentrations of reactive oxygen intermediates that simulate PKC and decrease ENaCs by enhancing endocytosis and its subsequent destruction by the proteasome. These novel findings suggest a mechanism for the influenza-induced rhinorrhea and life-threatening alveolar edema in humans. PMID:19596899

Lazrak, Ahmed; Iles, Karen E; Liu, Gang; Noah, Diana L; Noah, James W; Matalon, Sadis

2009-07-13

374

Action of reactive oxygen species in the antifungal mechanism of gemini-pyridinium salts against yeast.  

PubMed

We previously found that the gemini quaternary salt (gemini-QUAT) containing two pyridinium residues per molecule, 3,3'- (2,7-dioxaoctane) bis (1-decylpyridinium bromide) (3DOBP-4,10) , exerted fungicidal activity against Saccharomyces cerevisiae and caused respiration inhibition and the cytoplasmic leakage of ATP, magnesium, and potassium ions. Here, we investigated how the gemini-QUAT, 3DOBP-4,10, exerts more powerful antimicrobial activity than the mono-QUAT N-cetylpyridinium chloride (CPC) and examined the association between reactive oxygen species (ROS) and the antimicrobial mechanism. Antifungal assays showed that the activity of 3DOBP-4,10 against two yeasts, S. cerevisiae and Candida albicans, was significantly elevated under aerobic conditions, and largely reduced under anaerobic conditions (nitrogen atmosphere) . Adding radical scavengers such as superoxide dismutase, catalase and potassium iodide (KI) also decreased the fungicidal activity of 3DOBP-4,10 but negligibly affected that of CPC. We measured survival under static conditions and found that the rapid fungicidal profile of 3DOBP-4,10 was lost, whereas that of CPC was slightly affected in the presence of KI. Our results suggest that 3DOBP-4,10 exerts powerful antimicrobial activity by penetrating the cell wall and membrane, which then allows oxygen to enter the cells, where it participates in the generation of intracellular ROS. The activity could thus be attributable to a synergic antimicrobial combination of the disruption of organelle membranes by the QUAT and oxidative stress imposed by ROS. PMID:22790843

Shirai, Akihiro; Ueta, Shouko; Maseda, Hideaki; Kourai, Hiroki; Omasa, Takeshi

2012-06-01

375

Environmentally persistent free radicals (EPFRs). 1. Generation of reactive oxygen species in aqueous solutions.  

PubMed

Reactive oxygen species (ROS) generated by environmentally persistent free radicals (EPFRs) of 2-monochlorophenol, associated with CuO/silica particles, were detected using the chemical spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction with electron paramagnetic resonance (EPR) spectroscopy. Yields of hydroxyl radical ((•)OH), superoxide anion radical (O(2)(•-)), and hydrogen peroxide (H(2)O(2)) generated by EPFR-particle systems were reported. Failure to trap superoxide radicals in aqueous solvent, formed from reaction of EPFRs with molecular oxygen, results from fast transformation of the superoxide to hydrogen peroxide. However, formation of superoxide as an intermediate product in hydroxyl radical formation in aprotic solutions of dimethyl sulfoxide (DMSO) and acetonitrile (AcN) was observed. Experiments with superoxide dismutase (SOD) and catalase (CAT) confirmed formation of superoxide and hydrogen peroxide, respectively, in the presence of EPFRs. The large number of hydroxyl radicals formed per EPFR and monotonic increase of the DMPO-OH spin adduct concentration with incubation time suggest a catalytic cycle of ROS formation. PMID:21823585

Khachatryan, Lavrent; Vejerano, Eric; Lomnicki, Slawo; Dellinger, Barry

2011-09-15

376

Contribution of reactive oxygen species to UV-B-induced damage in bacteria.  

PubMed

The present work aimed to identify the reactive oxygen species (ROS) produced during UV-B exposure and their biochemical targets, in a set of bacterial isolates displaying different UV susceptibilities. For that, specific exogenous ROS scavengers (catalase/CAT, superoxide dismutase/SOD, sodium azide and mannitol) were used. Biological effects were assessed from total bacterial number, colony counts and heterotrophic activity (glucose uptake and respiration). DNA strand breakage, ROS generation, oxidative damage to proteins and lipids were used as markers of oxidative stress. Sodium azide conferred a statistically significant protection in terms of lipid oxidation and cell survival, suggesting that singlet oxygen might play an important role in UV-B induced cell inactivation. Mannitol exerted a significant protection against DNA strand breakage and protein carbonylation, assigning hydroxyl radicals to DNA and protein damage. The addition of exogenous CAT and SOD significantly protected the capacity for glucose uptake and respiration, suggesting that superoxide and H(2)O(2) are involved in the impairment of activity during UV-B exposure. The observation that amendment with ROS scavengers can sometimes also exert a pro-oxidant effect suggests that the intracellular oxidant status of the cell ultimately determines the efficiency of antioxidant defenses. PMID:23026387

Santos, Ana L; Gomes, Newton C M; Henriques, Isabel; Almeida, Adelaide; Correia, António; Cunha, Ângela

2012-09-05

377

Reactive Oxygen Species in the Regulation of Synaptic Plasticity and Memory  

PubMed Central

Abstract The brain is a metabolically active organ exhibiting high oxygen consumption and robust production of reactive oxygen species (ROS). The large amounts of ROS are kept in check by an elaborate network of antioxidants, which sometimes fail and lead to neuronal oxidative stress. Thus, ROS are typically categorized as neurotoxic molecules and typically exert their detrimental effects via oxidation of essential macromolecules such as enzymes and cytoskeletal proteins. Most importantly, excessive ROS are associated with decreased performance in cognitive function. However, at physiological concentrations, ROS are involved in functional changes necessary for synaptic plasticity and hence, for normal cognitive function. The fine line of role reversal of ROS from good molecules to bad molecules is far from being fully understood. This review focuses on identifying the multiple sources of ROS in the mammalian nervous system and on presenting evidence for the critical and essential role of ROS in synaptic plasticity and memory. The review also shows that the inability to restrain either age- or pathology-related increases in ROS levels leads to opposite, detrimental effects that are involved in impairments in synaptic plasticity and memory function. Antioxid. Redox Signal. 14, 2013–2054.

Klann, Eric

2011-01-01

378

Development of micellar reactive oxygen species assay for photosafety evaluation of poorly water-soluble chemicals.  

PubMed

A reactive oxygen species (ROS) assay was previously developed for photosafety assessment; however, the phototoxic potential of some chemicals cannot be evaluated because of their limited aqueous solubility. The present study was undertaken to develop a new micellar ROS (mROS) assay system for poorly water-soluble chemicals using a micellar solution of 0.5% (v/v) Tween 20 for solubility enhancement. In repeated mROS assay, intra- and inter-day precisions (coefficient of variation) were found to be below 11%, and the Z'-factors for singlet oxygen and superoxide suggested a large separation band between positive and negative standards. The ROS and mROS assays were applied to 65 phototoxins and 18 non-phototoxic compounds for comparative purposes. Of all 83 chemicals, 25 were unevaluable in the ROS assay due to poor solubility, but only 2 were in the mROS assay. Upon mROS assay on these model chemicals, the individual specificity was 76.5%, and the positive and negative predictivities were found to be 93.9% and 86.7%, respectively. The mROS assay provided 2 false negative predictions, although negative predictivity for the ROS assay was found to be 100%. Considering the pros and cons of these assays, strategic combined use of the ROS and mROS assays might be efficacious for reliable photosafety assessment with high applicability and predictivity. PMID:23727251

Seto, Yoshiki; Kato, Masashi; Yamada, Shizuo; Onoue, Satomi

2013-05-30

379

Ultraviolet Irradiation-Dependent Fluorescence Enhancement of Hemoglobin Catalyzed by Reactive Oxygen Species  

PubMed Central

Ultraviolet (UV) light has a potent effect on biological organisms. Hemoglobin, an oxygen-transport protein, plays an irreplaceable role in sustaining life of all vertebrates. In this study we scrutinize the effects of ultraviolet irradiation (UVI) as well as visible irradiation on the fluorescence characteristics of bovine hemoglobin (BHb) in vitro. Data show that UVI results in fluorescence enhancement of BHb in a dose-dependant manner. Furthermore, UVI-induced fluorescence enhancement is significantly increased when BHb is pretreated with hydrogen peroxide (H2O2), a type of reactive oxygen species (ROS). Meanwhile, The water-soluble antioxidant vitamin C suppresses this UVI-induced fluorescence enhancement. In contrast, green light irradiation does not lead to fluorescence enhancement of BHb no matter whether H2O2 is acting on the BHb solution or not. Taken together, these results indicate that catalysis of ROS and UVI-dependent irradiation play two key roles in the process of UVI-induced fluorescence enhancement of BHb.

Pan, Leiting; Wang, Xiaoxu; Yang, Shuying; Wu, Xian; Lee, Imshik; Zhang, Xinzheng; Rupp, Romano A.; Xu, Jingjun

2012-01-01

380

Photodecomposition of 4-chlorophenol by reactive oxygen species in UV/air system.  

PubMed

In this article, the photo-degradation of 4-chlorophenol (4-CP) under UV irradiation was studied with focus on the photodecomposition of 4-CP by reactive oxygen species (ROS). 4-CP underwent much faster and more complete degradation in UV/air system than in UV/N(2) system. In UV/air system, the addition of t-butanol, a well-known (•)OH scavenger, significantly impeded the degradation of 4-CP. In the presence of t-butanol, the tendencies for the degradation of 4-CP and the formation of intermediates in UV/air system were very similar to those in UV/N(2) system. In UV/air system, 4-CP was degraded by two pathways, direct photolysis by absorbing the photons and the oxidation via •OH. The contribution of direct photolysis and the oxidation via •OH to 4-CP decomposition were 17.2% and 82.8%, respectively based on the apparent kinetic constants. Hydrogen peroxide, which could produce •OH through photolysis, was formed in UV/air system. It was shown that dissolved oxygen, organic matter in excited state and hydrogen ion are all necessary for the formation of hydrogen peroxide. The formation mechanism of H(2)O(2) was proposed based on experimental evidence. PMID:21126819

Du, Yingxun; Fu, Q Shiang; Li, Yi; Su, Yaling

2010-11-12

381

Scavenging of reactive oxygen species by some nonsteroidal anti-inflammatory drugs and fenofibrate.  

PubMed

Ketoprofen and tolmetin are widely used nonsteroidal anti-inflammatory drugs, whereas fenofibrate belongs to a family of hypolipidemic drugs used in the prevention of cardiovascular diseases. The aim of this study was to assess effect of these drugs on reactions generating reactive oxygen species (ROS). The following generators of ROS were used: 18-crown-6/KO(2) dissolved in DMSO as a source of superoxide radical (O(.-)(2), the Fenton-like reaction (Cu/H(2)O(2)) for hydroxyl radical (HO(.)), 2,2'-azobis (2-amidino-propane) dichloride (AAPH) as peroxyl radical (ROO(.)) generator, and a mixture of alkaline aqueous H(2)O(2) and acetonitrile for singlet oxygen ((1)O(2)). Measurements were done using chemiluminescence, fluorescence, and spin-trapping with 2,2,6,6-tetramethylpiperidine combined with electron spin resonance spectroscopy (ESR), and a deoxyribose assay based on the spectrophotometry. The results obtained demonstrated that all tested drugs were active against O(.-)(2). There was a clear ranking of drug inhibition effects on chemiluminescence from the O(.-)(2) system: ketoprofen > tolmetin > fenofibrate. The examined compounds inhibited the HO(.)-dependent deoxyribose degradation and scavenged the ROO(.) concentration dependently with an order of potencies similar to that of the superoxide radical system. Hence, these results indicate that the studied drugs show broad ROS scavenging property and, as a consequence, might decrease tissue damage due to the ROS and thus to contribute to anti-inflammatory therapy. PMID:16245331

K?adna, Aleksandra; Aboul-Enein, Hassan Y; Kruk, Irena; Lichszteld, Krzysztof; Michalska, Teresa

2006-06-01

382

Efficient cyanoaromatic photosensitizers for singlet oxygen production: synthesis and characterization of the transient reactive species.  

PubMed

In order to graft cyanoaromatic molecules onto various inert supports, we designed two new cyanoanthracene derivatives of benzo[b]triphenylene-9,14-dicarbonitrile (DBTP, ), which already demonstrated good photosensitizing properties. We synthesized 3-(N-hydroxypropyl)carboxamido-9,14-dicyanobenzo[b]triphenylene, and 3-(N-N'-Boc-aminohexyl)carboxamido-9,14-dicyanobenzo[b]triphenylene, and compared their photophysical properties in acetonitrile relative to those of the parent compound and its carboxylic derivative 9,14-dicyanobenzo[b]triphenylene-3-carboxylic acid, . The transient species were analysed and the quantum yields of singlet oxygen production (??) determined in acetonitrile. The effect of chemical functionalization can be considered negligible, since absorption spectra, fluorescence emission spectra and fluorescence lifetimes do not significantly change with the substituent. The triplet-triplet absorption spectra and the triplet excited state lifetimes are similar for the whole series. For compounds high values of ??, close to that of the standard sensitizer 1H-phenalen-1-one (PN, ?? ? 1), and higher than that of the well-known photosensitizer 9,10-dicyanoanthracene (), are due to very efficient intersystem crossing from the singlet to the triplet excited state and subsequent energy transfer to ground state oxygen ((3)O2). They belong to a class of very efficient photosensitizers, absorbing visible light and stable under irradiation, they may be functionalized without significant changes to their photophysical behaviour, and grafted onto various supports. PMID:24013434

Ronzani, Filippo; Arzoumanian, Emmanuel; Blanc, Sylvie; Bordat, Patrice; Pigot, Thierry; Cugnet, Cyril; Oliveros, Esther; Sarakha, Mohamed; Richard, Claire; Lacombe, Sylvie

2013-09-25

383

Reactive oxygen species and the bacteriostatic and bactericidal effects of isoconazole nitrate.  

PubMed

Bacterial superinfections often occur in dermatomycoses, resulting in greatly inflamed or eczematous skin. The objective of this study was to evaluate the antibacterial efficacy of isoconazole nitrate (ISN), a broad-spectrum antimicrobial imidazole, commonly used to treat dermatomycoses. Several gram-positive bacteria minimal inhibitory concentrations (MICs) for ISN (ISN solution or ISN-containing creams: Travogen or corticosteroid-containing Travocort) and ampicillin were obtained using the broth-dilution method. Speed of onset of the bactericidal effect was determined with bacterial killing curves. Reactive oxygen species (ROS) were visualised by staining cells with singlet oxygen detector stain. Compared with ampicillin MICs, ISN MICs for Bacillus cereus, Staphylococcus haemolyticus and Staphylococcus hominis were lower and ISN MICs for Corynebacterium tuberculostearicum and Streptococcus salivarius were similar. Incubation with ISN led to a 50% kill rate for Staphylococcus aureus and methicillin-resistant strains (MRSA). Post-ISN incubation, 36% (30 min) and 90% (60 min) of S. aureus cells were positive for ROS. Isoconazole nitrate has a broad bacteriostatic and bactericidal action, also against a MRSA strain that was not reduced by the corticosteroid in the Travocort cream. Data suggest that the antibacterial effect of ISN may be ROS dependent. An antifungal agent with robust antibacterial activity can provide a therapeutic advantage in treating dermatomycoses with suspected bacterial superinfections. PMID:23574020

Czaika, Viktor A; Siebenbrock, Jan; Czekalla, Frank; Zuberbier, Torsten; Sieber, Martin A

2013-05-01

384

Alginate Overproduction Affects Pseudomonas aeruginosa Biofilm Structure and Function  

Microsoft Academic Search

During the course of chronic cystic fibrosis (CF) infections, Pseudomonas aeruginosa undergoes a conversion to a mucoid phenotype, which is characterized by overproduction of the exopolysaccharide alginate. Chronic P. aeruginosa infections involve surface-attached, highly antibiotic-resistant communities of microorganisms organized in biofilms. Although biofilm formation and the conversion to mucoidy are both important aspects of CF pathogenesis, the relationship between them

M. Hentzer; GAIL M. TEITZEL; GRANT J. BALZER; A. Heydorn; S. Molin; M. Givskov; MATTHEW R. PARSEK

2001-01-01

385

NADPH oxidases, reactive oxygen species, and hypertension: clinical implications and therapeutic possibilities.  

PubMed

Reactive oxygen species (ROS) influence many physiological processes including host defense, hormone biosynthesis, fertilization, and cellular signaling. Increased ROS production (termed "oxidative stress") has been implicated in various pathologies, including hypertension, atherosclerosis, diabetes, and chronic kidney disease. A major source for vascular and renal ROS is a family of nonphagocytic NAD(P)H oxidases, including the prototypic Nox2 homolog-based NAD(P)H oxidase, as well as other NAD(P)H oxidases, such as Nox1 and Nox4. Other possible sources include mitochondrial electron transport enzymes, xanthine oxidase, cyclooxygenase, lipoxygenase, and uncoupled nitric oxide synthase. NAD(P)H oxidase-derived ROS plays a physiological role in the regulation of endothelial function and vascular tone and a pathophysiological role in endothelial dysfunction, inflammation, hypertrophy, apoptosis, migration, fibrosis, angiogenesis, and rarefaction, important processes underlying cardiovascular and renal remodeling in hypertension and diabetes. These findings have evoked considerable interest because of the possibilities that therapies against nonphagocytic NAD(P)H oxidase to decrease ROS generation and/or strategies to increase nitric oxide (NO) availability and antioxidants may be useful in minimizing vascular injury and renal dysfunction and thereby prevent or regress target organ damage associated with hypertension and diabetes. Here we highlight current developments in the field of reactive oxygen species and cardiovascular disease, focusing specifically on the recently identified novel Nox family of NAD(P)H oxidases in hypertension. We also discuss the potential role of targeting ROS as a therapeutic possibility in the management of hypertension and cardiovascular disease. PMID:18227481

Paravicini, Tamara M; Touyz, Rhian M

2008-02-01

386

Zinc oxide nanoparticles selectively induce apoptosis in human cancer cells through reactive oxygen species  

PubMed Central

Background Zinc oxide nanoparticles (ZnO NPs) have received much attention for their implications in cancer therapy. It has been reported that ZnO NPs induce selective killing of cancer cells. However, the underlying molecular mechanisms behind the anticancer response of ZnO NPs remain unclear. Methods and results We investigated the cytotoxicity of ZnO NPs against three types of cancer cells (human hepatocellular carcinoma HepG2, human lung adenocarcinoma A549, and human bronchial epithelial BEAS-2B) and two primary rat cells (astrocytes and hepatocytes). Results showed that ZnO NPs exert distinct effects on mammalian cell viability via killing of all three types of cancer cells while posing no impact on normal rat astrocytes and hepatocytes. The toxicity mechanisms of ZnO NPs were further investigated using human liver cancer HepG2 cells. Both the mRNA and protein levels of tumor suppressor gene p53 and apoptotic gene bax were upregulated while the antiapoptotic gene bcl-2 was downregulated in ZnO NP-treated HepG2 cells. ZnO NPs were also found to induce activity of caspase-3 enzyme, DNA fragmentation, reactive oxygen species generation, and oxidative stress in HepG2 cells. Conclusion Overall, our data demonstrated that ZnO NPs selectively induce apoptosis in cancer cells, which is likely to be mediated by reactive oxygen species via p53 pathway, through which most of the anticancer drugs trigger apoptosis. This study provides preliminary guidance for the development of liver cancer therapy using ZnO NPs.

Akhtar, Mohd Javed; Ahamed, Maqusood; Kumar, Sudhir; Khan, MA Majeed; Ahmad, Javed; Alrokayan, Salman A

2012-01-01

387

Zofenopril inhibits the expression of adhesion molecules on endothelial cells by reducing reactive oxygen species.  

PubMed

Hypertension and coronary artery disease are intimately connected. The migration of circulating monocytes into the subendothelial occurs through the expression of some adhesion molecules on endothelial cells. The nuclear factor (NF)-kappaB, a redox-sensitive element, plays a key role in adhesion molecule gene induction. In this study we have compared the effects of two different angiotensin converting enzyme (ACE) inhibitors, one possessing an active sulfhydryl group (zofenopril) and one lacking this group (enalapril) on the cellular redox state (monitored by measuring intracellular reactive oxygen species and thiol status), expression of adhesion molecules, and activation of NF-kappaB in human umbilical vein endothelial cells (HUVECs). Zofenoprilat, the active form of zofenopril, significantly and dose dependently reduced the intracellular reactive oxygen species (ROS) and superoxide formation induced by oxidized low-density lipoprotein (ox-LDL) (P <.001) and tumor necrosis factor-alpha (TNF-alpha) (P <.001). Enalaprilat, the active form of enalapril, was ineffective. Zofenoprilat but not enalaprilat also decreased the consumption of the intracellular GSH induced by ox-LDL (P <.01) and TNF-alpha (P <.01). Although zofenoprilat significantly and dose dependently reduced the expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular cell adhesion molecule-1 (ICAM-1), and E-selectin induced by ox-LDL (P <.01) and TNF-alpha (P <.01) on HUVECs, enalaprilat did not. Ox-LDL and TNF-alpha increased the activation of NF-kappaB and the preincubation of HUVECs with zofenoprilat, but not with enalaprilat, dose dependently reduced its activation (P <.001). The conclusion is that the sulfhydryl (SH)-containing ACE inhibitors may be useful in inhibiting foam cell formation and thus slow the development of atherosclerosis. PMID:12372676

Cominacini, Luciano; Pasini, Anna; Garbin, Ulisse; Evangelista, Stefano; Crea, Attilio E G; Tagliacozzi, Debora; Nava, Cristina; Davoli, Anna; LoCascio, Vincenzo

2002-10-01

388

Reactive Oxygen Species Mediate Bactericidal Killing Elicited by Carbon Monoxide-releasing Molecules*  

PubMed Central

CO-releasing molecules (CO-RMs) were previously shown by us to be more potent bactericides than CO gas. This suggests a mechanism of action for CO-RM, which either potentiates the activity of CO or uses another CO-RM-specific effect. We have also reported that CORM-2 induces the expression of genes related to oxidative stress. In the present study we intend to establish whether the generation of reactive oxygen species by CO-RMs may indeed result in the inhibition of bacterial cellular function. We now report that two CO-RMs (CORM-2 and ALF062) stimulate the production of ROS in Escherichia coli, an effect that is abolished by addition of antioxidants. Furthermore, deletion of genes encoding E. coli systems involved in reactive oxygen species scavenging, namely catalases and superoxide dismutases, potentiates the lethality of CORM-2 due to an increase of intracellular ROS content. CORM-2 also induces the expression of the E. coli DNA repair/SOS system recA, and its inactivation enhances toxicity of CORM-2. Moreover, fluorescence microscopy images reveal that CORM-2 causes DNA lesions to bacterial cells. We also demonstrate that cells treated with CORM-2 contain higher levels of free iron arising from destruction of iron-sulfur proteins. Importantly, we show that CO-RMs generate hydroxyl radicals in a cell-free solution, a process that is abolished by scavenging CO. Altogether, we provide a novel insight into the molecular basis of CO-RMs action by showing that their bactericidal properties are linked to cell damage inflicted by the oxidative stress that they are able to generate.

Tavares, Ana Filipa N.; Teixeira, Miguel; Romao, Carlos C.; Seixas, Joao D.; Nobre, Ligia S.; Saraiva, Ligia M.

2011-01-01

389

Reactive Oxygen Species Production by Forward and Reverse Electron Fluxes in the Mitochondrial Respiratory Chain  

PubMed Central

Reactive oxygen species (ROS) produced in the mitochondrial respiratory chain (RC) are primary signals that modulate cellular adaptation to environment, and are also destructive factors that damage cells under the conditions of hypoxia/reoxygenation relevant for various systemic diseases or transplantation. The important role of ROS in cell survival requires detailed investigation of mechanism and determinants of ROS production. To perform such an investigation we extended our rule-based model of complex III in order to account for electron transport in the whole RC coupled to proton translocation, transmembrane electrochemical potential generation, TCA cycle reactions, and substrate transport to mitochondria. It fits respiratory electron fluxes measured in rat brain mitochondria fueled by succinate or pyruvate and malate, and the dynamics of NAD+ reduction by reverse electron transport from succinate through complex I. The fitting of measured characteristics gave an insight into the mechanism of underlying processes governing the formation of free radicals that can transfer an unpaired electron to oxygen-producing superoxide and thus can initiate the generation of ROS. Our analysis revealed an association of ROS production with levels of specific radicals of individual electron transporters and their combinations in species of complexes I and III. It was found that the phenomenon of bistability, revealed previously as a property of complex III, remains valid for the whole RC. The conditions for switching to a state with a high content of free radicals in complex III were predicted based on theoretical analysis and were confirmed experimentally. These findings provide a new insight into the mechanisms of ROS production in RC.

Selivanov, Vitaly A.; Votyakova, Tatyana V.; Pivtoraiko, Violetta N.; Zeak, Jennifer; Sukhomlin, Tatiana; Trucco, Massimo; Roca, Josep; Cascante, Marta

2011-01-01

390

Iron induces protection and necrosis in cultured cardiomyocytes: Role of reactive oxygen species and nitric oxide.  

PubMed

We investigate here the role of reactive oxygen species and nitric oxide in iron-induced cardiomyocyte hypertrophy or cell death. Cultured rat cardiomyocytes incubated with 20 microM iron (added as FeCl(3)-Na nitrilotriacetate, Fe-NTA) displayed hypertrophy features that included increased protein synthesis and cell size, plus realignment of F-actin filaments along with sarcomeres and activation of the atrial natriuretic factor gene promoter. Incubation with higher Fe-NTA concentrations (100 microM) produced cardiomyocyte death by necrosis. Incubation for 24 h with Fe-NTA (20-40 microM) or the nitric oxide donor Delta-nonoate increased iNOS mRNA but decreased iNOS protein levels; under these conditions, iron stimulated the activity and the dimerization of iNOS. Fe-NTA (20 microM) promoted short- and long-term generation of reactive oxygen species, whereas preincubation with l-arginine suppressed this response. Preincubation with 20 microM Fe-NTA also attenuated the necrotic cell death triggered by 100 microM Fe-NTA, suggesting that these preincubation conditions have cardioprotective effects. Inhibition of iNOS activity with 1400 W enhanced iron-induced ROS generation and prevented both iron-dependent cardiomyocyte hypertrophy and cardioprotection. In conclusion, we propose that Fe-NTA (20 microM) stimulates iNOS activity and that the enhanced NO production, by promoting hypertrophy and enhancing survival mechanisms through ROS reduction, is beneficial to cardiomyocytes. At higher concentrations, however, iron triggers cardiomyocyte death by necrosis. PMID:19969068

Munoz, Juan Pablo; Chiong, Mario; García, Lorena; Troncoso, Rodrigo; Toro, Barbra; Pedrozo, Zully; Diaz-Elizondo, Jessica; Salas, Daniela; Parra, Valentina; Núñez, Marco T; Hidalgo, Cecilia; Lavandero, Sergio

2009-12-04

391

In vitro inhibitory effect of mesenchymal stem cells on zymosan-induced production of reactive oxygen species  

Microsoft Academic Search

\\u000a In vitro chemiluminescent test showed that human bone marrow mesenchymal stem cells and conditioned media dose-dependently inhibit\\u000a production of reactive oxygen species by macrophages: 50% inhibition of chemiluminescence (compared to biocontrol) was observed\\u000a at 1:1 mesenchymal stem cell\\/macrophage ratio or after addition of 20–25% conditioned media to the incubation medium. The\\u000a observed mechanism of inhibition of production of reactive oxygen

A. F. Tsyb; V. N. Petrov; A. G. Konoplyannikov; E. V. Saypina; L. A. Lepechina; S. Sh. Kalsina; I. V. Semenkova; E. V. Agaeva

2008-01-01

392

Carcinogenic Metals Induce Hypoxia-inducible Factor-stimulated Transcription by Reactive Oxygen Species-independent Mechanism1  

Microsoft Academic Search

Nickel (Ni21) and cobalt (Co21) mimic hypoxia and were used as a tool to study the role of oxygen sensing and signaling cascades in the regulation of hypoxia-inducible gene expression. These metals can produce oxidative stress; therefore, it was conceivable that reactive oxygen species (ROS) may trigger signaling pathways resulting in the activation of the hypoxia- inducible factor (HIF)-1 transcription

Konstantin Salnikow; Weicheng Su; Mikhail V. Blagosklonny; Max Costa

393

Reactive oxygen species target specific tryptophan site in the mitochondrial ATP synthase.  

PubMed

The release of reactive oxygen species (ROS) as side products of aerobic metabolism in the mitochondria is an unavoidable consequence. As the capacity of organisms to deal with this exposure declines with age, accumulation of molecular damage caused by ROS has been defined as one of the central events during the ageing process in biological systems as well as in numerous diseases such as Alzheimer's and Parkinson's Dementia. In the filamentous fungus Podospora anserina, an ageing model with a clear defined mitochondrial etiology of ageing, in addition to the mitochondrial aconitase the ATP synthase alpha subunit was defined recently as a hot spot for oxidative modifications induced by ROS. In this report we show, that this reactivity is not randomly distributed over the ATP Synthase, but is channeled to a single tryptophan residue 503. This residue serves as an intra-molecular quencher for oxidative species and might also be involved in the metabolic perception of oxidative stress or regulation of enzyme activity. A putative metal binding site in the proximity of this tryptophan residue appears to be crucial for the molecular mechanism for the selective targeting of oxidative damage. PMID:22133636

Rexroth, Sascha; Poetsch, Ansgar; Rögner, Matthias; Hamann, Andrea; Werner, Alexandra; Osiewacz, Heinz D; Schäfer, Eva R; Seelert, Holger; Dencher, Norbert A

2011-11-19

394

Spontaneous generation of reactive oxygen species and effect on motility and fertilizability of sea urchin spermatozoa.  

PubMed

Summary We investigated the generation of reactive oxygen species (ROS) by spermatozoa in two species of sea urchin. ROS generation was accompanied by the initiation of motility and respiration and influenced the motility and fertilizability of spermatozoa. The sea urchin performs external fertilization in aerobic seawater. Sperm motility was initiated after spawning through Na+/H+ exchange. ROS generation was dependent on the respiration and sperm concentration and its generation was first observed at initiation of motility, via activation of respiration through ATP/ADP transport. The ROS generation rate increased at higher dilution ratios of spermatozoa, in a manner that was synchronous with the respiratory rate. This phenomenon resembled the previously defined 'sperm dilution effect' on respiration. The loss of motility and fertilizability was induced not only by treatment with hydrogen peroxide but also by sperm dilution. Storage of spermatozoa with a higher dilution ratio also accelerated the decrease in fertilizability. Thus, optimum sea urchin fertilizability is maintained by storage of undiluted spermatozoa on ice, in order to minimize oxidative stress and to maximize longevity. PMID:23174027

Kazama, Makoto; Sato, Taizo; Hino, Akiya

2012-10-31

395

Amputation-induced reactive oxygen species are required for successful Xenopus tadpole tail regeneration.  

PubMed

Understanding the molecular mechanisms that promote successful tissue regeneration is critical for continued advancements in regenerative medicine. Vertebrate amphibian tadpoles of the species Xenopus laevis and Xenopus tropicalis have remarkable abilities to regenerate their tails following amputation, through the coordinated activity of numerous growth factor signalling pathways, including the Wnt, Fgf, Bmp, Notch and TGF-? pathways. Little is known, however, about the events that act upstream of these signalling pathways following injury. Here, we show that Xenopus tadpole tail amputation induces a sustained production of reactive oxygen species (ROS) during tail regeneration. Lowering ROS levels, using pharmacological or genetic approaches, reduces the level of cell proliferation and impairs tail regeneration. Genetic rescue experiments restored both ROS production and the initiation of the regenerative response. Sustained increased ROS levels are required for Wnt/?-catenin signalling and the activation of one of its main downstream targets, fgf20 (ref. 7), which, in turn, is essential for proper tail regeneration. These findings demonstrate that injury-induced ROS production is an important regulator of tissue regeneration. PMID:23314862

Love, Nick R; Chen, Yaoyao; Ishibashi, Shoko; Kritsiligkou, Paraskevi; Lea, Robert; Koh, Yvette; Gallop, Jennifer L; Dorey, Karel; Amaya, Enrique

2013-01-13

396

Reactive Oxygen Species and Hyaluronidase 2 Regulate Airway Epithelial Hyaluronan Fragmentation*  

PubMed Central

Hyaluronidase 2 (Hyal2) is a hyaluronan (HA)-degrading enzyme found intracellularly or/and anchored to the plasma membrane through glycosylphosphatidylinositol (GPI). Normal human bronchial epithelial cells (NHBE) grown at the air-liquid interphase (ALI), treated with PI-specific phospholipase C (PI-PLC), exhibited increased Hyal activity in secretions and decreased protein and activity on the apical membrane, confirming that GPI-anchored Hyal2 is expressed in NHBE cells and it remains active in its soluble form. We have reported that HA degradation was mediated by reactive oxygen species (ROS) in human airways. Here we show that ROS increase Hyal2 expression and activity in NHBE cells and that the p38MAPK signaling pathway is involved in this effect. Hyal2 induction was confirmed by using small interfering RNA (siRNA) expressing lentivirus. These in vitro findings correlated in vivo with smokers, where increased Hyal2 immunoreactivity in the epithelium was associated with augmented levels of HA and the appearance of low molecular mass HA species in bronchial secretions. In summary, this work provides evidence that ROS induce Hyal2, suggesting that Hyal2 is likely responsible for the sustained HA fragmentation in the airway lumen observed in inflammatory conditions associated with oxidative stress.

Monzon, Maria E.; Fregien, Nevis; Schmid, Nathalie; Falcon, Nieves S.; Campos, Michael; Casalino-Matsuda, S. Marina; Forteza, Rosanna Malbran

2010-01-01

397

Methionine oxidation by reactive oxygen species: reaction mechanisms and relevance to Alzheimer's disease.  

PubMed

The oxidation of methionine plays an important role in vivo, during biological conditions of oxidative stress, as well as for protein stability in vitro. Depending on the nature of the oxidizing species, methionine may undergo a two-electron oxidation to methionine sulfoxide or one-electron oxidation to methionine radical cations. Both reaction mechanisms derive catalytic support from neighboring groups, which stabilize electron-deficient reaction centers. In vivo, methionine sulfoxide is subject to reduction by the methionine sulfoxide reductase (Msr) system, suggesting that some methionine sulfoxide residues may only be transiently involved in the deactivation of proteins through reactive oxygen species (ROS). Other methionine sulfoxide residues may accumulate, depending on the accessibility to Msr. Moreover, methionine sulfoxide levels may increase as a result of a lower abundance of active Msr and/or the required cofactors as a consequence of pathologies and biological aging. On the other hand, methionine radical cations will enter predominantly irreversible reaction channels, which ultimately yield carbon-centered and/or peroxyl radicals. These may become starting points for chain reactions of protein oxidation. This review will provide detailed mechanistic schemes for the reactions of various prominent, biologically relevant ROS with methionine and organic model sulfides. Emphasis will be given on the one-electron oxidation pathway, characterizing the physico-chemical parameters, which control this mechanism, and its physiological relevance, specifically for the oxidation and neurotoxicity of the Alzheimer's disease beta-amyloid peptide (betaAP). PMID:15680219

Schöneich, Christian

2004-10-27

398

Investigation of bacterial resistance to the immune system response: cepacian depolymerisation by reactive oxygen species.  

PubMed

Reactive oxygen species (ROS) are part of the weapons used by the immune system to kill and degrade infecting microorganisms. Bacteria can produce macromolecules, such as polysaccharides, that are able to scavenge ROS. Species belonging to the Burkholderia cepacia complex are involved in serious lung infection in cystic fibrosis patients and produce a characteristic polysaccharide, cepacian. The interaction between ROS and bacterial polysaccharides was first investigated by killing experiments, where bacteria cells were incubated with sodium hypochlorite (NaClO) with and without prior incubation with cepacian. The results showed that the polysaccharide had a protective effect towards bacterial cells. Cepacian was then treated with different concentrations of NaClO and the course of reactions was followed by means of capillary viscometry. The degradation products were characterised by size-exclusion chromatography, NMR and mass spectrometry. The results showed that hypochlorite depolymerised cepacian, removed side chains and O-acetyl groups, but did not cleave the glycosidic bond between glucuronic acid and rhamnose. The structure of some oligomers produced by NaClO oxidation is reported. PMID:22278934

Cuzzi, Bruno; Cescutti, Paola; Furlanis, Linda; Lagatolla, Cristina; Sturiale, Luisa; Garozzo, Domenico; Rizzo, Roberto

2012-01-25

399

Mechanism of citrinin-induced dysfunction of mitochondria. V. Effect on the homeostasis of the reactive oxygen species.  

PubMed

The effects of citrinin in the maintenance of the homeostasis of the reactive oxygen species in rat liver cells were evaluated. Citrinin (CTN) modifies the antioxidant enzymatic defences of cells through the inhibition of GSSG-reductase and transhydrogenase. No effect was observed on GSH-peroxidase, catalase, glucose 6-phosphate and 6 phosphogluconate dehydrogenases, and superoxide dismutase. The mycotoxin increased the generation of reactive oxygen species, stimulating the production of the superoxide anion in the respiratory chain. The results suggest that oxidative stress is an important mechanism, side by side with other effects previously shown, in the establishment of the cytotoxicity and cellular death provoked by CTN in several tissues. PMID:9377799

Ribeiro, S M; Chagas, G M; Campello, A P; Klüppel, M L

1997-09-01

400

Walker carcinosarcoma cells damage endothelial cells by the generation of reactive oxygen species.  

PubMed Central

The passage of circulating tumor cells across vessel walls is an important step in cancer metastasis and is promoted by endothelial injury. Because Walker carcinosarcoma 256 (W256) cells generate oxygen-derived free radicals after cellular activation, the authors tested the hypothesis that these cancer cells can damage endothelial monolayers by producing such reactive oxygen species. To confirm that oxygen-derived radicals can damage endothelial cells, 3H-2-deoxyglucose-labeled human endothelial cell monolayers were exposed to xanthine oxidase in the presence of 0.2 mmol/l xanthine. 3H-2-deoxyglucose release was observed after the addition of xanthine oxidase in concentrations ranging from 6.5 x 10(-3) to 52 x 10(-3) units/ml. The extent of damage correlated with xanthine oxidase-dependent chemiluminescence (r = 0.91). Chemiluminescence assays in the presence of 5 x 10(-5) M luminol confirmed activation of the W256 cells by 1 x 10(-6) M chemotactic peptide fMLP. When fMLP-activated activated W256 cells were incubated with endothelial monolayers, concentrations of 2 x 10(6) to 6 x 10(6) W256 cells/ml were found to cause a 27% increase in the specific release of 2-deoxyglucose after a 90-minute incubation. A small but significant increase in 3H-2-deoxyglucose release also was observed in the absence of fMLP. Detection of 3H-2-deoxyglucose release in the presence of activated or unactivated tumor cells was dependent on preincubating the endothelial cell monolayer with 1 mM buthionine sulfoximine, an inhibitor of glutathione synthesis. Under these conditions, the specific release of 3H-2-deoxyglucose was increased from nondetectable levels to 21%, in the presence of 6.5 x 10(-3) units of the oxidase. Cultured W256 cells promoted isotope release from endothelial cell monolayers when activated with phorbol myristate acetate. Catalase (1000 units/ml) inhibited the tumor cell-induced release of 3H-2-deoxyglucose by 84% whereas superoxide dismutase, even at concentrations of 1 mg/ml, had no effect. A requirement for cell contact was shown because addition of cell-free supernatants from fMLP activated tumor cells did not cause 3H-2-deoxyglucose release and because pretreatment of W256 cells with 1 microM cytochalasin B inhibited their ability to promote isotope release even while increasing tumor cell-generated chemiluminescence threefold. Electron microscopy revealed that fewer cytochalasin B-treated W256 cells were attached to the endothelial cell monolayer than in untreated controls. It is concluded that the W256 tumor cells can damage endothelial cells directly via a mechanism involving production of reactive oxygen species. Images Figure 5

Shaughnessy, S. G.; Buchanan, M. R.; Turple, S.; Richardson, M.; Orr, F. W.

1989-01-01

401

Phospholipase D signaling mediates reactive oxygen species-induced lung endothelial barrier dysfunction  

PubMed Central

Reactive oxygen species (ROS) have emerged as critical players in the pathophysiology of pulmonary disorders and diseases. Earlier, we have demonstrated that ROS stimulate lung endothelial cell (EC) phospholipase D (PLD) that generates phosphatidic acid (PA), a second messenger involved in signal transduction. In the current study, we investigated the role of PLD signaling in the ROS-induced lung vascular EC barrier dysfunction. Our results demonstrated that hydrogen peroxide (H2O2), a typical physiological ROS, induced PLD activation and altered the barrier function in bovine pulmonary artery ECs (BPAECs). 1-Butanol, the quencher of PLD, generated PA leading to the formation of physiologically inactive phosphatidyl butanol but not its biologically inactive analog, 2-butanol, blocked the H2O2-mediated barrier dysfunction. Furthermore, cell permeable C2 ceramide, an inhibitor of PLD but not the C2 dihydroceramide, attenuated the H2O2-induced PLD activation and enhancement of paracellular permeability of Evans blue conjugated albumin across the BPAEC monolayers. In addition, transfection of BPAECs with adenoviral constructs of hPLD1 and mPLD2 mutants attenuated the H2O2-induced barrier dysfunction, cytoskeletal reorganization and distribution of focal adhesion proteins. For the first time, this study demonstrated that the PLD-generated intracellular bioactive lipid signal mediator, PA, played a critical role in the ROS-induced barrier dysfunction in lung vascular ECs. This study also underscores the importance of PLD signaling in vascular leak and associated tissue injury in the etiology of lung diseases among critically ill patients encountering oxygen toxicity and excess ROS production during ventilator-assisted breathing.

Usatyuk, Peter V.; Kotha, Sainath R.; Parinandi, Narasimham L.; Natarajan, Viswanathan

2013-01-01

402

Anoxia-induced changes in reactive oxygen species and cyclic nucleotides in the painted turtle.  

PubMed

The Western painted turtle survives months without oxygen. A key adaptation is a coordinated reduction of cellular ATP production and utilization that may be signaled by changes in the concentrations of reactive oxygen species (ROS) and cyclic nucleotides (cAMP and cGMP). Little is known about the involvement of cyclic nucleotides in the turtle's metabolic arrest and ROS have not been previously measured in any facultative anaerobes. The present study was designed to measure changes in these second messengers in the anoxic turtle. ROS were measured in isolated turtle brain sheets during a 40-min normoxic to anoxic transition. Changes in cAMP and cGMP were determined in turtle brain, pectoralis muscle, heart and liver throughout 4 h of forced submergence at 20-22 degrees C. Turtle brain ROS production decreased 25% within 10 min of cyanide or N(2)-induced anoxia and returned to control levels upon reoxygenation. Inhibition of electron transfer from ubiquinol to complex III caused a smaller decrease in [ROS]. Conversely, inhibition of complex I increased [ROS] 15% above controls. In brain [cAMP] decreased 63%. In liver [cAMP] doubled after 2 h of anoxia before returning to control levels with prolonged anoxia. Conversely, skeletal muscle and heart [cAMP] remained unchanged; however, skeletal muscle [cGMP] became elevated sixfold after 4 h of submergence. In liver and heart [cGMP] rose 41 and 127%, respectively, after 2 h of anoxia. Brain [cGMP] did not change significantly during 4 h of submergence. We conclude that turtle brain ROS production occurs primarily between mitochondrial complexes I and III and decreases during anoxia. Also, cyclic nucleotide concentrations change in a manner suggestive of a role in metabolic suppression in the brain and a role in increasing liver glycogenolysis. PMID:17347830

Pamenter, Matthew Edward; Richards, Michael David; Buck, Leslie Thomas

2007-03-09

403

Flow cytometric measurement of reactive oxygen species production by normal and thalassaemic red blood cells.  

PubMed

Reactive oxygen species (ROS) contribute to the pathogenesis of several hereditary disorders of red blood cells (RBCs), including thalassaemia. We report here on a modified flow cytometric method for measuring ROS in normal and thalassaemic RBCs. RBCs were incubated with 0.4 mM 2',7'-dichlorofluorescin diacetate (DCFH-DA), then washed and further incubated either with or without 2 mM H2O2. Flow cytometric analysis showed that RBC fluorescence increased with time; it increased faster and reached higher intensity (by 10-30-fold) in H2O2-stimulated RBCs as compared to unstimulated RBCs. In both cases, the antioxidant N-acetyl-l-cysteine reduced fluorescence, confirming previous reports that DCFH fluorescence is mediated by ROS. While the fluorescence of unstimulated RBCs increased with time, probably because of exposure to atmospheric oxygen, in H2O2-stimulated RBCs fluorescence decreased after 30 min. The latter effect is most likely related to H2O2 decomposition by catalase as both sodium azide, an antimetabolite that inhibits catalase and low temperature increased the fluorescence of stimulated RBCs. Washing had a similar effect, suggesting that maintenance of the oxidised DCF requires a constant supply of ROS. We next studied RBCs of beta-thalassaemic patients. The results demonstrated a significantly higher ROS generation by stimulated and unstimulated thalassaemic RBCs compared to their normal counterparts. These results suggest that flow cytometry can be useful for measuring the ROS status of RBCs in various diseases and for studying chemical agents as antioxidants. PMID:12581189

Amer, Johnny; Goldfarb, Ada; Fibach, Eitan

2003-02-01

404

Pyrite-driven reactive oxygen species formation in simulated lung fluid: implications for coal workers' pneumoconiosis.  

PubMed

The origin of coal worker's pneumoconiosis (CWP) has been long debated. A recent epidemiological study shows a correlation between what is essentially the concentration of pyrite within coal and the prevalence of CWP in miners. Hydrogen peroxide and hydroxyl radical, both reactive oxygen species (ROS), form as byproducts of pyrite oxidative dissolution in air-saturated water. Motivated by the possible importance of ROS in the pathogenesis of CWP, we conducted an experimental study to evaluate if ROS form as byproducts in the oxidative dissolution of pyrite in simulated lung fluid (SLF) under biologically applicable conditions and to determine the persistence of pyrite in SLF. While the rate of pyrite oxidative dissolution in SLF is suppressed by 51% when compared to that in air-saturated water, the initial amount of hydrogen peroxide formed as a byproduct in SLF is nearly doubled. Hydroxyl radical is also formed in the experiments with SLF, but at lower concentrations than in the experiments with water. The formation of these ROS indicates that the reaction mechanism for pyrite oxidative dissolution in SLF is no different from that in water. The elevated hydrogen peroxide concentration in SLF suggests that the decomposition, via the Fenton mechanism to hydroxyl radical or with Fe(III) to form water and molecular oxygen, is initially inhibited by the presence of SLF components. On the basis of the oxidative dissolution rate of pyrite measured in this paper, it is calculated that a respirable two micron pyrite particle will take over 3 years to dissolve completely. PMID:21989857

Harrington, Andrea D; Hylton, Shavonne; Schoonen, Martin A A

2011-10-12

405

Release of Proteins from Intact Chloroplasts Induced by Reactive Oxygen Species during Biotic and Abiotic Stress  

PubMed Central

Plastids sustain life on this planet by providing food, feed, essential biomolecules and oxygen. Such diverse metabolic and biosynthetic functions require efficient communication between plastids and the nucleus. However, specific factors, especially large molecules, released from plastids that regulate nuclear genes have not yet been fully elucidated. When tobacco and lettuce transplastomic plants expressing GFP within chloroplasts, were challenged with Erwinia carotovora (biotic stress) or paraquat (abiotic stress), GFP was released into the cytoplasm. During this process GFP moves gradually towards the envelope, creating a central red zone of chlorophyll fluorescence. GFP was then gradually released from intact chloroplasts into the cytoplasm with an intact vacuole and no other visible cellular damage. Different stages of GFP release were observed inside the same cell with a few chloroplasts completely releasing GFP with detection of only red chlorophyll fluorescence or with no reduction in GFP fluorescence or transitional steps between these two phases. Time lapse imaging by confocal microscopy clearly identified sequence of these events. Intactness of chloroplasts during this process was evident from chlorophyll fluorescence emanated from thylakoid membranes and in vivo Chla fluorescence measurements (maximum quantum yield of photosystem II) made before or after infection with pathogens to evaluate their photosynthetic competence. Hydrogen peroxide and superoxide anion serve as signal molecules for generation of reactive oxygen species and Tiron, scavenger of superoxide anion, blocked release of GFP from chloroplasts. Significant increase in ion leakage in the presence of paraquat and light suggests changes in the chloroplast envelope to facilitate protein release. Release of GFP-RC101 (an antimicrobial peptide), which was triggered by Erwinia infection, ceased after conferring protection, further confirming this export phenomenon. These results suggest a novel signaling mechanism, especially for participation of chloroplast proteins (e.g. transcription factors) in retrograde signaling, thereby offering new opportunities to regulate pathways outside chloroplasts.

Singh, Nameirakpam D.; Daniell, Henry

2013-01-01

406

Phospholipase D signaling mediates reactive oxygen species-induced lung endothelial barrier dysfunction.  

PubMed

Reactive oxygen species (ROS) have emerged as critical players in the pathophysiology of pulmonary disorders and diseases. Earlier, we have demonstrated that ROS stimulate lung endothelial cell (EC) phospholipase D (PLD) that generates phosphatidic acid (PA), a second messenger involved in signal transduction. In the current study, we investigated the role of PLD signaling in the ROS-induced lung vascular EC barrier dysfunction. Our results demonstrated that hydrogen peroxide (H2O2), a typical physiological ROS, induced PLD activation and altered the barrier function in bovine pulmonary artery ECs (BPAECs). 1-Butanol, the quencher of PLD, generated PA leading to the formation of physiologically inactive phosphatidyl butanol but not its biologically inactive analog, 2-butanol, blocked the H2O2-mediated barrier dysfunction. Furthermore, cell permeable C2 ceramide, an inhibitor of PLD but not the C2 dihydroceramide, attenuated the H2O2-induced PLD activation and enhancement of paracellular permeability of Evans blue conjugated albumin across the BPAEC monolayers. In addition, transfection of BPAECs with adenoviral constructs of hPLD1 and mPLD2 mutants attenuated the H2O2-induced barrier dysfunction, cytoskeletal reorganization and distribution of focal adhesion proteins. For the first time, this study demonstrated that the PLD-generated intracellular bioactive lipid signal mediator, PA, played a critical role in the ROS-induced barrier dysfunction in lung vascular ECs. This study also underscores the importance of PLD signaling in vascular leak and associated tissue injury in the etiology of lung diseases among critically ill patients encountering oxygen toxicity and excess ROS production during ventilator-assisted breathing. PMID:23662182

Usatyuk, Peter V; Kotha, Sainath R; Parinandi, Narasimham L; Natarajan, Viswanathan

2013-01-01

407

Photoreactivity of carboxylated single-walled carbon nanotubes in sunlight: reactive oxygen species production in water.  

PubMed

Very limited information exists on transformation processes of carbon nanotubes in the natural aquatic environment. Because the conjugated pi-bond structure of these materials is efficient in absorbing sunlight, photochemical transformations are a potential fate process with reactivity predicted to vary with their diameter, chirality, number and type of defects, functionalization, residual metal catalyst and amorphous carbon content, and with the composition of the water, including the type and composition of materials that act to disperse them into the aqueous environment. In this study, the photochemical reactions involving colloidal dispersions of carboxylated single-walled carbon nanotubes (SWNT-COOH) in sunlight were examined. Production of reactive oxygen species (ROS) during irradiation occurs and is evidence for potential further phototransformation and may be significant in assessing their overall environmental impacts. In aerated samples exposed to sunlight or to lamps that emit light only within the solar spectrum, the probe compounds, furfuryl alcohol (FFA), tetrazolium salts (NBT2+ and XTT), and p-chlorobenzoic acid (pCBA), were used to indicate production of 1O2, O2.-, and .OH, respectively. All three ROS were produced in the presence of SWNT-COOH and molecular oxygen (3O2). 1O2 production was confirmed by observing enhanced FFA decay in deuterium oxide, attenuated decay of FFA in the presence of azide ion, and the lack of decay of FFA in deoxygenated solutions. Photogeneration of O2.- and .OH was confirmed by applying superoxide dismutase (SOD) and tert-butanol assays, respectively. In air-equilibrated suspensions, the loss of 0.2 mM FFA in 10 mg/L SWNT-COOH was approximately 85% after 74 h. Production of 1O2 was not dependent on pH from 7 to 11; however photoinduced aggregation was observed at pH 3. PMID:20687543

Chen, Chia-Ying; Jafvert, Chad T

2010-09-01

408

Influence of particle size and reactive oxygen species on cobalt chrome nanoparticle-mediated genotoxicity.  

PubMed

Patients with cobalt chrome (CoCr) metal-on-metal (MOM) implants may be exposed to a wide size range of metallic nanoparticles as a result of wear. In this study we have characterised the biological responses of human fibroblasts to two types of synthetically derived CoCr particles [(a) from a tribometer (30 nm) and (b) thermal plasma technology (20, 35, and 80 nm)] in vitro, testing their dependence on nanoparticle size or the generation of oxygen free radicals, or both. Metal ions were released from the surface of nanoparticles, particularly from larger (80 nm) particles generated by thermal plasma technology. Exposure of fibroblasts to these nanoparticles triggered rapid (2 h) generation of reactive oxygen species (ROS) that could be eliminated by inhibition of NADPH oxidase, suggesting that it was mediated by phagocytosis of the particles. The exposure also caused a more prolonged, MitoQ sensitive production of ROS (24 h), suggesting involvement of mitochondria. Consequently, we recorded elevated levels of aneuploidy, chromosome clumping, fragmentation of mitochondria and damage to the cytoskeleton particularly to the microtubule network. Exposure to the nanoparticles resulted in misshapen nuclei, disruption of mature lamin B1 and increased nucleoplasmic bridges, which could be prevented by MitoQ. In addition, increased numbers of micronuclei were observed and these were only partly prevented by MitoQ, and the incidence of micronuclei and ion release from the nanoparticles were positively correlated with nanoparticle size, although the cytogenetic changes, modifications in nuclear shape and the amount of ROS were not. These results suggest that cells exhibit diverse mitochondrial ROS-dependent and independent responses to CoCr particles, and that nanoparticle size and the amount of metal ion released are influential. PMID:23433773

Raghunathan, Vijay Krishna; Devey, Michael; Hawkins, Sue; Hails, Lauren; Davis, Sean A; Mann, Stephen; Chang, Isaac T; Ingham, Eileen; Malhas, Ashraf; Vaux, David J; Lane, Jon D; Case, Charles P

2013-02-20

409

Neutral sphingomyelinase, NADPH oxidase and reactive oxygen species. Role in acute hypoxic pulmonary vasoconstriction.  

PubMed

The molecular mechanisms underlying hypoxic pulmonary vasoconstriction (HPV) are not yet properly understood. Mitochondrial electron transport chain (ETC) and NADPH oxidase have been proposed as possible oxygen sensors, with derived reactive oxygen species (ROS) playing key roles in coupling the sensor(s) to the contractile machinery. We have recently reported that activation of neutral sphingomyelinase (nSMase) and protein kinase C ? (PKC?) participate in the signalling cascade of HPV. Herein, we studied the significance of nSMase in controlling ROS production rate in rat pulmonary artery (PA) smooth muscle cells and thereby HPV in rat PA. ROS production (analyzed by dichlorofluorescein and dihydroethidium fluorescence) was increased by hypoxia in endothelium-denuded PA segments and their inhibition prevented hypoxia-induced voltage-gated potassium channel (K(V) ) inhibition and pulmonary vasoconstriction. Consistently, H(2) O(2) , or its analogue t-BHP, decreased K(V) currents and induced a contractile response, mimicking the effects of hypoxia. Inhibitors of mitochondrial ETC (rotenone) and NADPH oxidase (apocynin) prevented hypoxia-induced ROS production, K(V) channel inhibition and vasoconstriction. Hypoxia induced p47(phox) phosphorylation and its interaction with caveolin-1. Inhibition of nSMase (GW4869) or PKC? prevented p47(phox) phosphorylation and ROS production. The increase in ceramide induced by hypoxia (analyzed by immunocytochemistry) was inhibited by rotenone. Exogenous ceramide increased ROS production in a PKC? sensitive manner. We propose an integrated signalling pathway for HPV which includes nSMase-PKC?-NADPH oxidase as a necessary step required for ROS production and vasoconstriction. PMID:21792922

Frazziano, Giovanna; Moreno, Laura; Moral-Sanz, Javier; Menendez, Carmen; Escolano, Lucía; Gonzalez, Constancio; Villamor, Eduardo; Alvarez-Sala, Jose Luis; Cogolludo, Angel L; Perez-Vizcaino, Francisco

2011-10-01

410

Process of aerenchyma formation and reactive oxygen species induced by waterlogging in wheat seminal roots.  

PubMed

The development and regulation of aerenchyma in waterlogged conditions were studied in the seminal roots of wheat. Evans blue staining and the first cell death position indicated that the cortical cell death began at the root mid-cortex cells in flooding conditions. Continuous waterlogging treatment caused the spread of cell death from the mid-cortex to the neighboring cells and well-developed aerenchyma was formed after 72 h. Meanwhile, the formation of radial oxygen loss barrier was observed in the exodermis owing to the induction of Casparian bands and lignin deposition. Analysis of aerenchyma along the wheat root revealed that aerenchyma formed at 10 mm from the root tip, significantly increased toward the center of the roots, and decreased toward the basal region of the root. In situ detection of radial oxygen species (ROS) showed that ROS accumulation started in the mid-cortex cells, where cell death began indicating that cell death was probably accompanied by ROS production. Further waterlogging treatments resulted in the accumulation of ROS in the cortical cells, which were the zone for aerenchyma development. Accumulation and distribution of H2O2 at the subcellular level were revealed by ultracytochemical localization, which further verified the involvement of ROS in the cortical cell death process (i.e., aerenchyma formation). Furthermore, gene expression analysis indicated that ROS production might be the result of up-regulation of genes encoding for ROS-producing enzymes and the down-regulation of genes encoding for ROS-detoxifying enzymes. These results suggest that aerenchyma development in wheat roots starts in the mid-cortex cells and its formation is regulated by ROS. PMID:23975011

Xu, Q T; Yang, L; Zhou, Z Q; Mei, F Z; Qu, L H; Zhou, G S

2013-08-22

411

Reactive oxygen species are involved in nickel inhibition of dna repair  

SciTech Connect

Nickel has been shown to inhibit DNA repair in a way that may play a role in its toxicity. Since nickel treatment increases cellular reactive oxygen species (ROS), we have investigated the involvement of ROS in nickel inhibition of DNA repair. Inhibition of glutathione synthesis or catalase activity increased the enhancing effect of nickel on the cytotoxicity of ultraviolet (UV) light. Inhibition of catalase and glutathione peroxidase activities also enhanced the retardation effect of nickel on the rejoining of DNA strand breaks accumulated by hydroxyurea plus cytosine-{beta}-D-arabinofuranoside in UV-irradiated cells. Since DNA polymerization and ligation are involved in the DNA-break rejoining, we have investigated the effect of ROS on these two steps in an extract of Chinese hamster ovary cells. Nickel inhibition of the incorporation of ({sup 3}H)dTTP into the DNase l-activated calf thymus DNA was stronger than the ligation of poly(dA){center_dot}oligo(dT), whereas H{sub 2}O{sub 2} was more potent in inhibiting DNA ligation than DNA polymerization. Nickel, in the presence of H{sub 2}O{sub 2}, exhibited a synergistic inhibition on both DNA polymerization and ligation and caused protein fragmentation. In addition, glutathione could completely recover the inhibition by nickel or H{sub 2}O{sub 2} alone but only partially recover the inhibition by nickel plus H{sub 2}O{sub 2}. Therefore, nickel may bind to DNA-repair enzymes and generate oxygen-free radicals to cause protein degradation in situ. This irreversible damage to the proteins involved in DNA repair, replication, recombination, and transcription could be important for the toxic effects of nickel. 60 refs., 6 figs., 4 tabs.

Lynn, S.; Yew, F.H.; Chen, K.S.; Jan, K.Y.

1997-06-01

412

Release of proteins from intact chloroplasts induced by reactive oxygen species during biotic and abiotic stress.  

PubMed

Plastids sustain life on this planet by providing food, feed, essential biomolecules and oxygen. Such diverse metabolic and biosynthetic functions require efficient communication between plastids and the nucleus. However, specific factors, especially large molecules, released from plastids that regulate nuclear genes have not yet been fully elucidated. When tobacco and lettuce transplastomic plants expressing GFP within chloroplasts, were challenged with Erwinia carotovora (biotic stress) or paraquat (abiotic stress), GFP was released into the cytoplasm. During this process GFP moves gradually towards the envelope, creating a central red zone of chlorophyll fluorescence. GFP was then gradually released from intact chloroplasts into the cytoplasm with an intact vacuole and no other visible cellular damage. Different stages of GFP release were observed inside the same cell with a few chloroplasts completely releasing GFP with detection of only red chlorophyll fluorescence or with no reduction in GFP fluorescence or transitional steps between these two phases. Time lapse imaging by confocal microscopy clearly identified sequence of these events. Intactness of chloroplasts during this process was evident from chlorophyll fluorescence emanated from thylakoid membranes and in vivo Chla fluorescence measurements (maximum quantum yield of photosystem II) made before or after infection with pathogens to evaluate their photosynthetic competence. Hydrogen peroxide and superoxide anion serve as signal molecules for generation of reactive oxygen species and Tiron, scavenger of superoxide anion, blocked release of GFP from chloroplasts. Significant increase in ion leakage in the presence of paraquat and light suggests changes in the chloroplast envelope to facilitate protein release. Release of GFP-RC101 (an antimicrobial peptide), which was triggered by Erwinia infection, ceased after conferring protection, further confirming this export phenomenon. These results suggest a novel signaling mechanism, especially for participation of chloroplast proteins (e.g. transcription factors) in retrograde signaling, thereby offering new opportunities to regulate pathways outside chloroplasts. PMID:23799142

Kwon, Kwang-Chul; Verma, Dheeraj; Jin, Shuangxia; Singh, Nameirakpam D; Daniell, Henry

2013-06-14

413

Mobile Phone Radiation Induces Reactive Oxygen Species Production and DNA Damage in Human Spermatozoa In Vitro  

PubMed Central

Background In recent times there has been some controversy over the impact of electromagnetic radiation on human health. The significance of mobile phone radiation on male reproduction is a key element of this debate since several studies have suggested a relationship between mobile phone use and semen quality. The potential mechanisms involved have not been established, however, human spermatozoa are known to be particularly vulnerable to oxidative stress by virtue of the abundant availability of substrates for free radical attack and the lack of cytoplasmic space to accommodate antioxidant enzymes. Moreover, the induction of oxidative stress in these cells not only perturbs their capacity for fertilization but also contributes to sperm DNA damage. The latter has, in turn, been linked with poor fertility, an increased incidence of miscarriage and morbidity in the offspring, including childhood cancer. In light of these associations, we have analyzed the influence of RF-EMR on the cell biology of human spermatozoa in vitro. Principal Findings Purified human spermatozoa were exposed to radio-frequency electromagnetic radiation (RF-EMR) tuned to 1.8 GHz and covering a range of specific absorption rates (SAR) from 0.4 W/kg to 27.5 W/kg. In step with increasing SAR, motility and vitality were significantly reduced after RF-EMR exposure, while the mitochondrial generation of reactive oxygen species and DNA fragmentation were significantly elevated (P<0.001). Furthermore, we also observed highly significant relationships between SAR, the oxidative DNA damage bio-marker, 8-OH-dG, and DNA fragmentation after RF-EMR exposure. Conclusions RF-EMR in both the power density and frequency range of mobile phones enhances mitochondrial reactive oxygen species generation by human spermatozoa, decreasing the motility and vitality of these cells while stimulating DNA base adduct formation and, ultimately DNA fragmentation. These findings have clear implications for the safety of extensive mobile phone use by males of reproductive age, potentially affecting both their fertility and the health and wellbeing of their offspring.

De Iuliis, Geoffry N.; Newey, Rhiannon J.; King, Bruce V.; Aitken, R. John

2009-01-01

414

Manumycin inhibits STAT3, telomerase activity, and growth of glioma cells by elevating intracellular reactive oxygen species generation  

Microsoft Academic Search

The poor prognosis of glioblastoma multiforme and lack of effective therapy have necessitated the identification of new treatment strategies. We have previously reported that elevation of oxidative stress induces apoptosis of glioma cells. Because the farnesyltransferase inhibitor manumycin is known to induce reactive oxygen species (ROS) generation, we evaluated the effects of manumycin on glioma cells. Manumycin induced glioma cell

Deobrat Dixit; Vivek Sharma; Sadashib Ghosh; Nitin Koul; Prakash Kumar Mishra; Ellora Sen

2009-01-01

415

Source of early reactive oxygen species in the apoptosis induced by transforming growth factor-? in fetal rat hepatocytes  

Microsoft Academic Search

Transforming growth factor-? (TGF-?) induces an oxidative stress process in hepatocytes that mediates its apoptotic activity. To determine the cellular source of the early reactive oxygen species (ROS) generated by fetal rat hepatocytes in response to TGF-?, we used inhibitors that block different ROS-producing systems. Diphenyleneiodonium, which inhibits NADPH oxidase and other flavoproteins, completely blocked the increase in ROS induced

Blanca Herrera; Miguel M Murillo; Alberto Álvarez-Barrientos; Jesús Beltrán; Margarita Fernández; Isabel Fabregat

2004-01-01

416

Reactive oxygen species (ROS) mediates the mitochondrial-dependent apoptosis induced by transforming growth factor b in fetal hepatocytes  

Microsoft Academic Search

Treatment of fetal rat hepatocytes with transforming growth factor beta (TGF-b) is followed by apoptotic cell death. Analysis of radical oxygen species (ROS) content and mitochondrial transmembrane po- tential (Dcm), using specific fluorescent probes in FACScan and confocal microscopy, showed that TGF-b mediates ROS production that precedes the loss of Dcm, the release of cytochrome c, and the activation of

BLANCA HERRERA; M. ALVAREZ; ARANZAZU SANCHEZ; MARGARITA FERNANDEZ; CESAR RONCERO; MANUEL BENITO; ISABEL FABREGAT

417

Glutathione is implied in the control of 7-ketocholesterol-induced apoptosis, which is associated with radical oxygen species production  

Microsoft Academic Search

In a number of experimental systems, inhibition of apoptosis by antioxidants has led to the production of radical oxygen species (ROS) in cer- tain apoptotic forms of cell death. Since antioxidant therapies can reduce vascular dysfunctions in hyper- cholesterolemic patients who frequently have in- creased plasma levels of oxysterols constituting po- tent inducers of apoptosis, we speculate that oxysterol-induced apoptosis

GERARD LIZARD; SERGE GUELDRY; OLIVIER SORDET; SERGE MONIER; ANNE ATHIAS; CAROLE MIGUET; GINETTE BESSEDE; STEPHANIE LEMAIRE; ERIC SOLARY; PHILIPPE GAMBERT

418

Simultaneous analysis of reactive oxygen species and reduced glutathione content in living cells by polychromatic flow cytometry  

Microsoft Academic Search

Reactive oxygen species (ROS) are continuously produced in the cell as a consequence of aerobic metabolism, and are controlled by several antioxidant mechanisms. An accurate measurement of ROS is essential to evaluate the redox status of the cell, or the effects of molecules with the pro-oxidant or antioxidant activity. Here we report a cytofluorimetric technique for measuring simultaneously, at the

Roberta Ferraresi; Leonarda Troiano; Erika Roat; Lara Gibellini; Linda Bertoncelli; Milena Nasi; Marcello Pinti; Andrea Cossarizza

2009-01-01

419

Involvement of oxidative stress response genes in redox homeostasis, the level of reactive oxygen species, and ageing in Saccharomyces cerevisiae  

Microsoft Academic Search

Saccharomyces cerevisiae mutants lacking oxidative stress response genes were used to investigate which genes are required under normal aerobic conditions to maintain cellular redox homeostasis, using intracellular glutathione redox potential (glutathione Eh) to indicate the redox environment of the cells. Levels of reactive oxygen species (ROS) and mitochondrial membrane potentials (MMP) were also assessed by FACS using dihydroethidium and rhodamine

Tamara Drakulic; Mark D. Temple; Ron Guido; Stefanie Jarolim; Michael Breitenbach; Paul V. Attfield; Ian W. Dawes

2005-01-01

420

The reactive oxygen species—total antioxidant capacity score is a new measure of oxidative stress to predict male infertility  

Microsoft Academic Search

There is growing evidence that oxidative stress significantly impairs sperm function, and plays a major role in the aetiology The imbalance between reactive oxygen species (ROS) of defective sperm function. This may lead to the onset of production and total antioxidant capacity (TAC) in seminal male infertility via mechanisms involving the induction of fluid indicates oxidative stress and is correlated

Rakesh K. Sharma; Fabio F. Pasqualotto; David R. Nelson; Anthony J. Thomas Jr; Ashok Agarwal

421

A Permeable Cuticle Is Associated with the Release of Reactive Oxygen Species and Induction of Innate Immunity  

Microsoft Academic Search

Wounded leaves of Arabidopsis thaliana show transient immunity to Botrytis cinerea, the causal agent of grey mould. Using a fluorescent probe, histological staining and a luminol assay, we now show that reactive oxygen species (ROS), including H2O2 and O2?, are produced within minutes after wounding. ROS are formed in the absence of the enzymes Atrboh D and F and can

Floriane LHaridon; Angélique Besson-Bard; Matteo Binda; Mario Serrano; Eliane Abou-Mansour; Francine Balet; Henk-Jan Schoonbeek; Stephane Hess; Ricardo Mir; José Léon; Olivier Lamotte; Jean-Pierre Métraux

2011-01-01

422

Cadmium induction of reactive oxygen species activates the mTOR pathway, leading to neuronal cell death  

Microsoft Academic Search

Cadmium (Cd), a highly toxic environmental pollutant, induces neurodegenerative diseases. Recently we have demonstrated that Cd induces neuronal apoptosis in part through activation of the mammalian target of rapamycin (mTOR) pathway. However, the underlying mechanism is unknown. Here we show that Cd induces the generation of reactive oxygen species (ROS) by upregulating the expression of NADPH oxidase 2 and its

Long Chen; Baoshan Xu; Lei Liu; Yan Luo; Hongyu Zhou; Wenxing Chen; Tao Shen; Xiuzhen Han; Christopher D. Kontos; Shile Huang

2011-01-01

423

Increased Formation of Reactive Oxygen Species After Permanent and Reversible Middle Cerebral Artery Occlusion in the Rat  

Microsoft Academic Search

In barbiturate-anesthetized rats, we induced 3 hours of permanent middle cerebral artery occlusion (MCAO) by an intraluminal thread (n = 6), or 1 hour MCAO followed by 2 hours of reperfusion (n = 6). Through a closed cranial window over the parietal cortex, the production of reactive oxygen species(ROS) was measured in the infarct border using online in vivo chemiluminescence

Oliver Peters; Tobias Back; Ute Lindauer; Christina Busch; Dirk Megow; Jens Dreier; Ulrich Dirnagl

1998-01-01

424

REACTIVE OXYGEN SPECIES IN WHOLE BLOOD, BLOOD PLASMA AND BREAST MILK: VALIDATION OF A POTENTIAL MARKER OF EXPOSURE AND EFFECT  

EPA Science Inventory

Reactive oxygen species (ROS) are recognized to contribute to the pathobiology of many diseases. We have applied a simple chemiluminescent (CL) probe to detect ROS in various biological fluids (plasma, whole blood, urine and breast milk) in an environmental arsenic drinking wate...

425

Generation of Reactive Oxygen and Anti-Oxidant Species by Hydrodynamically-Stressed Suspensions of Morinda citrofolia  

Technology Transfer Automated Retrieval System (TEKTRAN)

The generation of reactive oxygen species (ROS) by plant cell suspension cultures, in response to the imposition of both biotic and abiotic stress, is well-documented. This study investigated the generation of hydrogen peroxide by hydrodynamically-stressed cultures of Morinda citrifolia, over a 5-ho...

426

Dermal Toxicity and Environmental Contamination: Electron Transfer, Reactive Oxygen Species, Oxidative Stress, Cell Signaling, and Protection by Antioxidants  

Microsoft Academic Search

\\u000a Many papers have addressed the role of electron transfer (ET) (electron movement from one site to another), reactive oxygen\\u000a species (ROS), and oxidative stress (OS) in producing cellular insults and, thereby, toxicity in major organs. The present\\u000a review provides evidence for the same mechanistic theme as it applies to skin toxicants.

Peter Kovacic; Ratnasamy Somanathan

427

Chloroplast and reactive oxygen species involvement in apoptotic-like programmed cell death in Arabidopsis suspension cultures  

Microsoft Academic Search

Chloroplasts produce reactive oxygen species (ROS) during cellular stress. ROS are known to act as regulators of programmed cell death (PCD) in plant and animal cells, so it is possible that chloroplasts have a role in regulating PCD in green tissue. Arabidopsis thaliana cell suspension cultures are model systems in which to test this, as here it is shown that

Siamsa M. Doyle; Mark Diamond; Paul F. McCabe

2010-01-01

428

The effect of reactive oxygen species on the biosynthesis of collagen and glycosaminoglycans in cultured human dermal fibroblasts  

Microsoft Academic Search

The purpose of this study was to evaluate the possibility that the biological changes observed in connective tissue matrix components of photoaging skin may be induced by an alteration of biosynthesis in fibroblasts damaged by reactive oxygen species (ROS). We investigated the effect of ROS induced by xanthine and the xanthine oxidase system on the biosynthesis of connective tissue matrix

H. Tanaka; T. Okada; H. Konishi; T. Tsuji