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Sample records for oxygen species causing

  1. Gulf War illnesses are autoimmune illnesses caused by reactive oxygen species which were caused by nerve agent prophylaxis.

    Science.gov (United States)

    Moss, J I

    2012-08-01

    Gulf War illnesses (GWI share many of the features of chronic fatigue syndrome (CFS) and both CFS and GWI may be the result of chronic immune system processes. The main suspected cause for GWI, the drug pyridostigmine bromide (PB), has been shown to cause neuronal damage from reactive oxygen species (ROS). ROS have been associated with IgM mediated autoimmune responses against ROS induced neoepitopes in depressed patients and this may also apply to CFS. It therefore follows that the drug used in the Gulf War caused ROS, the ROS modified native molecules, and that this trigged the autoimmune condition we refer to as Gulf War illnesses. Similar mechanisms may apply to other autoimmune illnesses. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Increased reactive oxygen species levels cause ER stress and cytotoxicity in andrographolide treated colon cancer cells.

    Science.gov (United States)

    Banerjee, Aditi; Banerjee, Vivekjyoti; Czinn, Steven; Blanchard, Thomas

    2017-04-18

    Chemotherapy continues to play an essential role in the management of many cancers including colon cancer, the third leading cause of death due to cancer in the United States. Many naturally occurring plant compounds have been demonstrated to possess anti-cancer cell activity and have the potential to supplement existing chemotherapy strategies. The plant metabolite andrographolide induces cell death in cancer cells and apoptosis is dependent upon the induction of endoplasmic reticulum stress (ER stress) leading to the unfolded protein response (UPR). The goal of the present study was to determine the mechanism by which andrographolide induces ER stress and to further evaluate its role in promoting cell death pathways. The T84 and COLO 205 cancer cell lines were used to demonstrate that andrographolide induces increased ROS levels, corresponding anti-oxidant response molecules, and reduced mitochondrial membrane potential. No increases in ROS levels were detected in control colon fibroblast cells. Andrographolide-induced cell death, UPR signaling, and CHOP, Bax, and caspase 3 apoptosis elements were all inhibited in the presence of the ROS scavenger NAC. Additionally, andrographolide-induced suppression of cyclins B1 and D1 were also reversed in the presence of NAC. Finally, Akt phosphorylation and phospho-mTOR levels that are normally suppressed by andrographolide were also expressed at normal levels in the absence of ROS. These data demonstrate that andrographolide induces ER stress leading to apoptosis through the induction of ROS and that elevated ROS also play an important role in down-regulating cell cycle progression and cell survival pathways as well.

  3. Reactive Oxygen Species along with Reactive Nitrogen Species (ROS/RNS) as the Main Cause of Multiple Sclerosis

    OpenAIRE

    Somayeh Zaminpira; Sorush Niknamian

    2017-01-01

    Multiple Sclerosis is a condition of demyelination of the nerve cells in the brain and spinal cord. It is possible that multiple factors are involved in causing multiple sclerosis, including DNA defects in nuclear and mitochondrial genomes, viral infection, hypoxia, oxidative stress, lack of sunlight, and increased macrophages and lymphocytes in the brain. This meta-analysis has gone through many researches and reviews to find the similarities and differences in the cause of this disease. The...

  4. Reactive Oxygen Species

    DEFF Research Database (Denmark)

    Franchina, Davide G.; Dostert, Catherine; Brenner, Dirk

    2018-01-01

    T cells are a central component of defenses against pathogens and tumors. Their effector functions are sustained by specific metabolic changes that occur upon activation, and these have been the focus of renewed interest. Energy production inevitably generates unwanted products, namely reactive...... and transcription factors, influencing the outcome of the T cell response. We discuss here how ROS can directly fine-tune metabolism and effector functions of T cells....... oxygen species (ROS), which have long been known to trigger cell death. However, there is now evidence that ROS also act as intracellular signaling molecules both in steady-state and upon antigen recognition. The levels and localization of ROS contribute to the redox modeling of effector proteins...

  5. Intracellular zinc flux causes reactive oxygen species mediated mitochondrial dysfunction leading to cell death in Leishmania donovani.

    Directory of Open Access Journals (Sweden)

    Anjali Kumari

    Full Text Available Leishmaniasis caused by Leishmania parasite is a global threat to public health and one of the most neglected tropical diseases. Therefore, the discovery of novel drug targets and effective drug is a major challenge and an important goal. Leishmania is an obligate intracellular parasite that alternates between sand fly and human host. To survive and establish infections, Leishmania parasites scavenge and internalize nutrients from the host. Nevertheless, host cells presents mechanism like nutrient restriction to inhibit microbial growth and control infection. Zinc is crucial for cellular growth and disruption in its homeostasis hinders growth and survival in many cells. However, little is known about the role of zinc in Leishmania growth and survival. In this study, the effect of zinc on the growth and survival of L.donovani was analyzed by both Zinc-depletion and Zinc-supplementation using Zinc-specific chelator N, N, N', N'-tetrakis (2-pyridylmethyl ethylenediamine (TPEN and Zinc Sulfate (ZnSO4. Treatment of parasites with TPEN rather than ZnSO4 had significantly affected the growth in a dose- and time-dependent manner. The pre-treatment of promastigotes with TPEN resulted into reduced host-parasite interaction as indicated by decreased association index. Zn depletion resulted into flux in intracellular labile Zn pool and increased in ROS generation correlated with decreased intracellular total thiol and retention of plasma membrane integrity without phosphatidylserine exposure in TPEN treated promastigotes. We also observed that TPEN-induced Zn depletion resulted into collapse of mitochondrial membrane potential which is associated with increase in cytosolic calcium and cytochrome-c. DNA fragmentation analysis showed increased DNA fragments in Zn-depleted cells. In summary, intracellular Zn depletion in the L. donovani promastigotes led to ROS-mediated caspase-independent mitochondrial dysfunction resulting into apoptosis-like cell death

  6. Pulmonary Oxidative Stress, Inflammation and Cancer: Respirable Particulate Matter, Fibrous Dusts and Ozone as Major Causes of Lung Carcinogenesis through Reactive Oxygen Species Mechanisms

    Directory of Open Access Journals (Sweden)

    Spyridon Loridas

    2013-08-01

    Full Text Available Reactive oxygen or nitrogen species (ROS, RNS and oxidative stress in the respiratory system increase the production of mediators of pulmonary inflammation and initiate or promote mechanisms of carcinogenesis. The lungs are exposed daily to oxidants generated either endogenously or exogenously (air pollutants, cigarette smoke, etc.. Cells in aerobic organisms are protected against oxidative damage by enzymatic and non-enzymatic antioxidant systems. Recent epidemiologic investigations have shown associations between increased incidence of respiratory diseases and lung cancer from exposure to low levels of various forms of respirable fibers and particulate matter (PM, at occupational or urban air polluting environments. Lung cancer increases substantially for tobacco smokers due to the synergistic effects in the generation of ROS, leading to oxidative stress and inflammation with high DNA damage potential. Physical and chemical characteristics of particles (size, transition metal content, speciation, stable free radicals, etc. play an important role in oxidative stress. In turn, oxidative stress initiates the synthesis of mediators of pulmonary inflammation in lung epithelial cells and initiation of carcinogenic mechanisms. Inhalable quartz, metal powders, mineral asbestos fibers, ozone, soot from gasoline and diesel engines, tobacco smoke and PM from ambient air pollution (PM10 and PM2.5 are involved in various oxidative stress mechanisms. Pulmonary cancer initiation and promotion has been linked to a series of biochemical pathways of oxidative stress, DNA oxidative damage, macrophage stimulation, telomere shortening, modulation of gene expression and activation of transcription factors with important role in carcinogenesis. In this review we are presenting the role of ROS and oxidative stress in the production of mediators of pulmonary inflammation and mechanisms of carcinogenesis.

  7. Molecular mechanism of the short-term cardiotoxicity caused by 2',3'-dideoxycytidine (ddC): modulation of reactive oxygen species levels and ADP-ribosylation reactions.

    Science.gov (United States)

    Skuta, G; Fischer, G M; Janaky, T; Kele, Z; Szabo, P; Tozser, J; Sumegi, B

    1999-12-15

    The short-term cardiac side effects of 2',3'-dideoxycytidine (ddC, zalcitabine) were studied in rats in order to understand the biochemical events contributing to the development of ddC-induced cardiomyopathy. In developing animals, ddC treatment provoked a surprisingly rapid appearance of cardiac malfunctions characterized by prolonged RR, PR, and QT intervals and J point depression. The energy metabolism in the heart was compromised, characterized by a decreased creatine phosphate/creatine ratio (from 2.05 normal value to 0.75) and a decreased free ATP/ADP ratio (from 332 normal value to 121). The activity of respiratory complexes (NADH: cytochrome c oxidoreductase and cytochrome oxidase) also decreased significantly. Southern blot and polymerase chain reaction analysis did not show deletions or a decrease in the quantity of mitochondrial DNA (mtDNA) deriving from ddC-treated rat hearts, indicating that under our experimental conditions, ddC-induced heart abnormalities were not the direct consequence of mtDNA-related damage. The ddC treatment of rats significantly increased the formation of reactive oxygen species (ROS) in heart and skeletal muscle as determined by the oxidation of non-fluorescent dihydrorhodamine123 to fluorescent rhodamine123 and the oxidation of cellular proteins determined from protein carbonyl content. An activation of the nuclear poly-(ADP-ribose) polymerase (EC 2.4.2.30) and an increase in the mono-ADP-ribosylation of glucose-regulated protein and desmin were observed in the cardiac tissue from ddC-treated animals. A decrease in the quantity of heat shock protein (HSP)70s was also detected, while the level of HSP25 and HSP60 remained unchanged. Surprisingly, ddC treatment induced a skeletal muscle-specific decrease in the quantity of three proteins, one of which was identified by N-terminal sequencing as myoglobin, and another by tandem mass spectrometer sequencing as triosephosphate isomerase (EC 5.3.1.1). These data show that the short

  8. Oxygen negative glow: reactive species and emissivity

    International Nuclear Information System (INIS)

    Sahli, Khaled

    1991-01-01

    This research thesis addresses the study of a specific type of oxygen plasma created by electron beams (1 keV, 20 mA/cm"2), negative glow of a luminescent discharge in abnormal regime. The objective is to test the qualities of this plasma as source of two 'active' species of oxygen (singlet molecular oxygen and atomic oxygen) which are useful in applications. The experiment mainly bears on the use of VUV (120 to 150 nm) absorption spectroscopy measurements of concentrations of these both species, and on the recording of plasma emissivity space profiles in the visible region (450 to 850 nm). It appears that low concentrations of singlet oxygen definitely exclude this type of discharge for iodine laser applications. On the contrary, concentrations measured for atomic oxygen show it is a good candidate for the oxidation of large surfaces by sheets of beams. The satisfying comparison of emissivity results with a published model confirm the prevailing role of fast electrons, and gives evidence of an important effect of temperature: temperature can reach 1000 K, and this is in agreement with the presented measurement [fr

  9. Reactive oxygen species in health and disease : Finding the right balance

    NARCIS (Netherlands)

    van der Wijst, Monique

    2016-01-01

    When oxygen takes up an electron, reactive oxygen species are formed. These free radicals can react with important molecules in our body (DNA, proteins), just like iron rusts (oxidation). Too many reactive oxygen species, called oxidative stress, result in cellular damage causing either cell death

  10. Reactive oxygen species, health and longevity

    OpenAIRE

    Vittorio Emanuele Bianchi; Giancarlo Falcioni

    2016-01-01

    Reactive oxygen species (ROS) are considered responsible of ageing in animal and humans. Mitochondria are both source and target of ROS. Various strategies to reduce ROS production have been considered to extend lifespan. Caloric restriction, exercise, and antioxidants are thought to be able to protect cells from structural and functional damage. However, there is evidence that ROS production has a detrimental effect on health, but at physiological levels are necessary to stimulate longevity....

  11. Imaging Reactive Oxygen Species in Arthritis

    Directory of Open Access Journals (Sweden)

    Wei-Tsung Chen

    2004-07-01

    Full Text Available Reactive oxygen species (ROS have been shown to play a role in the pathogenesis of arthritides. Luminol was used as the primary reporter of ROS and photons resulting from the chemiluminescence reaction were detected using a super-cooled CCD photon counting system. Luminol was injected intravenously into groups of animals with different models of arthritis. Imaging signal correlated well with the severity of arthritis in focal and pan-arthritis as determined by histological measurement of ROS by formazan. Measurements were highly reproducible, sensitive, and repeatable. In vivo chemiluminescence imaging is expected to become a useful modality to elucidate the role of ROS in the pathogenesis of arthritides and in determining therapeutic efficacy of protective therapies.

  12. Catalase and superoxide dismutase conjugated with platelet-endothelial cell adhesion molecule antibody distinctly alleviate abnormal endothelial permeability caused by exogenous reactive oxygen species and vascular endothelial growth factor.

    Science.gov (United States)

    Han, Jingyan; Shuvaev, Vladimir V; Muzykantov, Vladimir R

    2011-07-01

    Reactive oxygen species (ROS) superoxide anion (O(2)()) and hydrogen peroxide (H(2)O(2)) produced by activated leukocytes and endothelial cells in sites of inflammation or ischemia cause endothelial barrier dysfunction that may lead to tissue edema. Antioxidant enzymes (AOEs) catalase and superoxide dismutase (SOD) conjugated with antibodies to platelet-endothelial cell adhesion molecule-1 (PECAM-1) specifically bind to endothelium, quench the corresponding ROS, and alleviate vascular oxidative stress and inflammation. In the present work, we studied the effects of anti-PECAM/catalase and anti-PECAM/SOD conjugates on the abnormal permeability manifested by transendothelial electrical resistance decline, increased fluorescein isothiocyanate-dextran influx, and redistribution of vascular endothelial-cadherin in human umbilical vein endothelial cell (HUVEC) monolayers. Anti-PECAM/catalase protected HUVEC monolayers against H(2)O(2)-induced endothelial barrier dysfunction. Polyethylene glycol-conjugated catalase exerted orders of magnitude lower endothelial uptake and no protective effect, similarly to IgG/catalase. Anti-PECAM/catalase, but not anti-PECAM/SOD, alleviated endothelial hyperpermeability caused by exposure to hypoxanthine/xanthine oxidase, implicating primarily H(2)O(2) in the disruption of the endothelial barrier in this model. Thrombin-induced endothelial permeability was not affected by treatment with anti-PECAM/AOEs or the NADPH oxidase inhibitor apocynin or overexpression of AOEs, indicating that the endogenous ROS play no key role in thrombin-mediated endothelial barrier dysfunction. In contrast, anti-PECAM/SOD, but not anti-PECAM/catalase, inhibited a vascular endothelial growth factor (VEGF)-induced increase in endothelial permeability, identifying a key role of endogenous O(2)() in the VEGF-mediated regulation of endothelial barrier function. Therefore, AOEs targeted to endothelial cells provide versatile molecular tools for testing the roles of

  13. Mechanisms of group A Streptococcus resistance to reactive oxygen species.

    Science.gov (United States)

    Henningham, Anna; Döhrmann, Simon; Nizet, Victor; Cole, Jason N

    2015-07-01

    Streptococcus pyogenes, also known as group A Streptococcus (GAS), is an exclusively human Gram-positive bacterial pathogen ranked among the 'top 10' causes of infection-related deaths worldwide. GAS commonly causes benign and self-limiting epithelial infections (pharyngitis and impetigo), and less frequent severe invasive diseases (bacteremia, toxic shock syndrome and necrotizing fasciitis). Annually, GAS causes 700 million infections, including 1.8 million invasive infections with a mortality rate of 25%. In order to establish an infection, GAS must counteract the oxidative stress conditions generated by the release of reactive oxygen species (ROS) at the infection site by host immune cells such as neutrophils and monocytes. ROS are the highly reactive and toxic byproducts of oxygen metabolism, including hydrogen peroxide (H2O2), superoxide anion (O2•(-)), hydroxyl radicals (OH•) and singlet oxygen (O2*), which can damage bacterial nucleic acids, proteins and cell membranes. This review summarizes the enzymatic and regulatory mechanisms utilized by GAS to thwart ROS and survive under conditions of oxidative stress. © FEMS 2015.

  14. Reactive oxygen species, health and longevity

    Directory of Open Access Journals (Sweden)

    Vittorio Emanuele Bianchi

    2016-09-01

    Full Text Available Reactive oxygen species (ROS are considered responsible of ageing in animal and humans. Mitochondria are both source and target of ROS. Various strategies to reduce ROS production have been considered to extend lifespan. Caloric restriction, exercise, and antioxidants are thought to be able to protect cells from structural and functional damage. However, there is evidence that ROS production has a detrimental effect on health, but at physiological levels are necessary to stimulate longevity. They play an important effect on secondary signal transduction stimulating innate immunology and mitochondriogenesis. During exercise at moderate intensity, skeletal muscles generate ROS that are necessary for the remodelling of the muscular cells. Physical inactivity determines excessive ROS production and muscle atrophy. Caloric restriction (CR can reduce ROS generation and improve longevity while antioxidant supplementation has shown a negative effect on longevity reducing the muscle adaptation to exercise and increasing mortality risk in patients with chronic diseases. The role of ROS in chronic diseases in also influenced by sex steroids that decrease in aging. The physiology of longevity is the result of integrated biological mechanisms that influence mitochondrial function and activity. The main objective of this review is to evaluate the effects of ROS on mitochondriogenesis and lifespan extension.

  15. Magnetic nanoparticles: reactive oxygen species generation and potential therapeutic applications

    Science.gov (United States)

    Mai, Trang; Hilt, J. Zach

    2017-07-01

    Magnetic nanoparticles have been demonstrated to produce reactive oxygen species (ROS), which play a major role in various cellular pathways, via Fenton and Haber-Weiss reaction. ROS act as a double-edged sword inside the body. At normal conditions, the generation of ROS is in balance with their elimination by scavenger systems, and they can promote cell proliferation as well as differentiation. However, at an increased level, they can cause damages to protein, lead to cellular apoptosis, and contribute to many diseases including cancer. Many recent studies proposed a variety of strategies to either suppress toxicity of ROS generation or exploit the elevated ROS levels for cancer therapy.

  16. Chilli anthracnose disease caused by Colletotrichum species.

    Science.gov (United States)

    Than, Po Po; Prihastuti, Haryudian; Phoulivong, Sitthisack; Taylor, Paul W J; Hyde, Kevin D

    2008-10-01

    Anthracnose disease is one of the major economic constraints to chilli production worldwide, especially in tropical and subtropical regions. Accurate taxonomic information is necessary for effective disease control management. In the Colletotrichum patho-system, different Colletotrichum species can be associated with anthracnose of the same host. Little information is known concerning the interactions of the species associated with the chilli anthracnose although several Colletotrichum species have been reported as causal agents of chilli anthracnose disease worldwide. The ambiguous taxonomic status of Colletotrichum species has resulted in inaccurate identification which may cause practical problems in plant breeding and disease management. Although the management and control of anthracnose disease are still being extensively researched, commercial cultivars of Capsicum annuum that are resistant to the pathogens that cause chilli anthracnose have not yet been developed. This paper reviews the causal agents of chilli anthracnose, the disease cycle, conventional methods in identification of the pathogen and molecular approaches that have been used for the identification of Colletotrichum species. Pathogenetic variation and population structure of the causal agents of chilli anthracnose along with the current taxonomic status of Colletotrichum species are discussed. Future developments leading to the disease management strategies are suggested.

  17. Redox mechanism of reactive oxygen species in exercise

    Directory of Open Access Journals (Sweden)

    Feng He

    2016-11-01

    Full Text Available It is well known that regular exercise benefits health. However, unaccustomed and/or exhaustive exercise can generate excessive reactive oxygen species (ROS, leading to oxidative stress-related tissue damage and impaired muscle contractility. ROS are produced in both aerobic and anaerobic exercise. Although mitochondria, NADPH oxidases and xanthine oxidase have all been identified as contributors to ROS production, the exact redox mechanisms underlying exercise-induced oxidative stress remain elusive. Interestingly, moderate exposure to ROS is necessary to induce the body’s adaptive responses such as the activation of antioxidant defense mechanisms. Dietary antioxidant manipulation can also reduce ROS levels and muscle fatigue, as well as enhance exercise recovery. To elucidate the complex role of ROS in exercise, this article updates on new findings of ROS origins within skeletal muscles associated with various types of exercises such as endurance, sprint and mountain climbing, corresponding antioxidant defense systems as well as dietary manipulation against damage caused by ROS.

  18. Calcific Uremic Arteriolopathy: Pathophysiology, Reactive Oxygen Species and Therapeutic Approaches

    Directory of Open Access Journals (Sweden)

    Kurt M. Sowers

    2010-01-01

    Full Text Available Calcific uremic arteriolopathy (CUA/calciphylaxis is an important cause of morbidity and mortality in patients with chronic kidney disease requiring renal replacement. Once thought to be rare, it is being increasingly recognized and reported on a global scale. The uremic milieu predisposes to multiple metabolic toxicities including increased levels of reactive oxygen species and inflammation. Increased oxidative stress and inflammation promote this arteriolopathy by adversely affecting endothelial function resulting in a prothrombotic milieu and significant remodeling effects on vascular smooth muscle cells. These arteriolar pathological effects include intimal hyperplasia, inflammation, endovascular fibrosis and vascular smooth muscle cell apoptosis and differentiation into bone forming osteoblast-like cells resulting in medial calcification. Systemic factors promoting this vascular condition include elevated calcium, parathyroid hormone and hyperphosphatemia with consequent increases in the calcium × phosphate product. The uremic milieu contributes to a marked increased in upstream reactive oxygen species—oxidative stress and subsequent downstream increased inflammation, in part, via activation of the nuclear transcription factor NFκB and associated downstream cytokine pathways. Consitutive anti-calcification proteins such as Fetuin-A and matrix GLA proteins and their signaling pathways may be decreased, which further contributes to medial vascular calcification. The resulting clinical entity is painful, debilitating and contributes to the excess morbidity and mortality associated with chronic kidney disease and end stage renal disease. These same histopathologic conditions also occur in patients without uremia and therefore, the term calcific obliterative arteriolopathy could be utilized in these conditions.

  19. Oxygen-independent direct deoxyribonucleic acid backbone breakage caused by rose bengal and visible light

    Energy Technology Data Exchange (ETDEWEB)

    Peak, M J; Peak, J G; Foote, C S; Krinsky, N I

    1984-01-01

    An oxygen enhancement ratio of 10 for the induction of backbone single-strand breaks (SSBs) in purified deoxyribonucleic acid (DNA) by monochromatic 365 nm UV radiation was obtained. Similarly, a dose reduction factor of 10 was observed when the DNA was irradiated in the presence of 0.1 M diazabicyclo(2.2.2)octane (DABCO). To determine whether this breakage of DNA was due to the action of a reactive oxygen species such as singlet oxygen, we used the photosensitizing dye Rose Bengal and visible light as a system for generating singlet oxygen. Treatment of the DNA with Rose Bengal and 545 nm monochromatic light enhanced the rate of induction of SSBs six times, compared with the rate we obtained when the light was used alone. Elimination of oxygen or addition of 0.1 M DABCO during the 545 nm irradiation in the presence of Rose Bengal did not alter the enhancement of SSBs in the DNA caused by Rose Bengal and 545 nm radiation. The induction of SSBs in the DNA caused by irradiation of the DNA by 545 nm light in the presence of Rose Bengal was not enhanced by the use of D/sub 2/O instead of H/sub 2/O as a solvent. The results indicate that Rose Bengal plus visible light can cause biological damage without the intermediacy of reactive oxygen species, i.e. Rose Bengal and visible light can react directly with biological material, in reactions that appear to be type I photosensitized processes, independent of singlet oxygen as an intermediate.

  20. Kinetics of oxygen species in an electrically driven singlet oxygen generator

    Science.gov (United States)

    Azyazov, V. N.; Torbin, A. P.; Pershin, A. A.; Mikheyev, P. A.; Heaven, M. C.

    2015-12-01

    The kinetics of oxygen species in the gaseous medium of a discharge singlet oxygen generator has been revisited. Vibrationally excited ozone O3(υ) formed in O + O2 recombination is thought to be a significant agent in the deactivation of singlet oxygen O2(a1Δ), oxygen atom removal and ozone formation. It is shown that the process O3(υ ⩾ 2) + O2(a1Δ) → 2O2 + O is the main O2(a1Δ) deactivation channel in the post-discharge zone. If no measures are taken to decrease the oxygen atom concentration, the contribution of this process to the overall O2(a1Δ) removal is significant, even in the discharge zone. A simplified model for the kinetics of vibrationally excited ozone is proposed. Calculations based on this model yield results that are in good agreement with the experimental data.

  1. Oxygen pathway modeling estimates high reactive oxygen species production above the highest permanent human habitation.

    Directory of Open Access Journals (Sweden)

    Isaac Cano

    Full Text Available The production of reactive oxygen species (ROS from the inner mitochondrial membrane is one of many fundamental processes governing the balance between health and disease. It is well known that ROS are necessary signaling molecules in gene expression, yet when expressed at high levels, ROS may cause oxidative stress and cell damage. Both hypoxia and hyperoxia may alter ROS production by changing mitochondrial Po2 (PmO2. Because PmO2 depends on the balance between O2 transport and utilization, we formulated an integrative mathematical model of O2 transport and utilization in skeletal muscle to predict conditions to cause abnormally high ROS generation. Simulations using data from healthy subjects during maximal exercise at sea level reveal little mitochondrial ROS production. However, altitude triggers high mitochondrial ROS production in muscle regions with high metabolic capacity but limited O2 delivery. This altitude roughly coincides with the highest location of permanent human habitation. Above 25,000 ft., more than 90% of exercising muscle is predicted to produce abnormally high levels of ROS, corresponding to the "death zone" in mountaineering.

  2. Species rarity: definition, causes, and classification

    Science.gov (United States)

    Curtis H. Flather; Carolyn Hull Sieg

    2007-01-01

    In virtually all ecological communities around the world, most species are represented by few individuals, and most individuals come from only a few of the most common species. Why this distribution of species abundances is so regularly observed among different taxonomic sets in geographically diverse systems is a question that has received considerable theoretical and...

  3. Effects of proline on photosynthesis, root reactive oxygen species ...

    African Journals Online (AJOL)

    Effects of 0.2 mM proline applied to saline nutrient solution on biomass, chlorophyll content, photosynthetic parameters, reactive oxygen species and antioxidant enzymes activities of two melon cultivars (cv. Yuhuang and cv. Xuemei) were examined. Results indicate that exogenous proline increased the fresh and dry ...

  4. Formation of reactive oxygen species in rat epithelial cells upon ...

    Indian Academy of Sciences (India)

    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 ...

  5. Luminometric determination of antioxidant capacity towards individual reactive oxygen species

    Czech Academy of Sciences Publication Activity Database

    Komrsková, D.; Lojek, Antonín; Hrbáč, J.; Číž, Milan

    2005-01-01

    Roč. 3, č. 1 (2005), S25 [Cells VI - Biological Days /18./. 24.10.2005-26.10.2005, České Budějovice] R&D Projects: GA ČR(CZ) GA524/01/1219 Institutional research plan: CEZ:AV0Z50040507 Keywords : chemiluminescence * reactive oxygen species * scavenger Subject RIV: BO - Biophysics

  6. Generation of Reactive Oxygen Species from Silicon Nanowires

    Directory of Open Access Journals (Sweden)

    Stephen S. Leonard

    2014-01-01

    Full Text Available Processing and synthesis of purified nanomaterials of diverse composition, size, and properties is an evolving process. Studies have demonstrated that some nanomaterials have potential toxic effects and have led to toxicity research focusing on nanotoxicology. About two million workers will be employed in the field of nanotechnology over the next 10 years. The unknown effects of nanomaterials create a need for research and development of techniques to identify possible toxicity. Through a cooperative effort between National Institute for Occupational Safety and Health and IBM to address possible occupational exposures, silicon-based nanowires (SiNWs were obtained for our study. These SiNWs are anisotropic filamentary crystals of silicon, synthesized by the vapor-liquid-solid method and used in bio-sensors, gas sensors, and field effect transistors. Reactive oxygen species (ROS can be generated when organisms are exposed to a material causing cellular responses, such as lipid peroxidation, H 2 O 2 production, and DNA damage. SiNWs were assessed using three different in vitro environments (H 2 O 2 , RAW 264.7 cells, and rat alveolar macrophages for ROS generation and possible toxicity identification. We used electron spin resonance, analysis of lipid peroxidation, measurement of H 2 O 2 production, and the comet assay to assess generation of ROS from SiNW and define possible mechanisms. Our results demonstrate that SiNWs do not appear to be significant generators of free radicals.

  7. Molecular and biochemical mechanisms in teratogenesis involving reactive oxygen species

    International Nuclear Information System (INIS)

    Wells, Peter G.; Bhuller, Yadvinder; Chen, Connie S.; Jeng, Winnie; Kasapinovic, Sonja; Kennedy, Julia C.; Kim, Perry M.; Laposa, Rebecca R.; McCallum, Gordon P.; Nicol, Christopher J.; Parman, Toufan; Wiley, Michael J.; Wong, Andrea W.

    2005-01-01

    Developmental pathologies may result from endogenous or xenobiotic-enhanced formation of reactive oxygen species (ROS), which oxidatively damage cellular macromolecules and/or alter signal transduction. This minireview focuses upon several model drugs (phenytoin, thalidomide, methamphetamine), environmental chemicals (benzo[a]pyrene) and gamma irradiation to examine this hypothesis in vivo and in embryo culture using mouse, rat and rabbit models. Embryonic prostaglandin H synthases (PHSs) and lipoxygenases bioactivate xenobiotics to free radical intermediates that initiate ROS formation, resulting in oxidation of proteins, lipids and DNA. Oxidative DNA damage and embryopathies are reduced in PHS knockout mice, and in mice treated with PHS inhibitors, antioxidative enzymes, antioxidants and free radical trapping agents. Thalidomide causes embryonic DNA oxidation in susceptible (rabbit) but not resistant (mouse) species. Embryopathies are increased in mutant mice deficient in the antioxidative enzyme glucose-6-phosphate dehydrogenase (G6PD), or by glutathione (GSH) depletion, or inhibition of GSH peroxidase or GSH reductase. Inducible nitric oxide synthase knockout mice are partially protected. Inhibition of Ras or NF-kB pathways reduces embryopathies, implicating ROS-mediated signal transduction. Atm and p53 knockout mice deficient in DNA damage response/repair are more susceptible to xenobiotic or radiation embryopathies, suggesting a teratological role for DNA damage, consistent with enhanced susceptibility to methamphetamine in ogg1 knockout mice with deficient repair of oxidative DNA damage. Even endogenous embryonic oxidative stress carries a risk, since untreated G6PD- or ATM-deficient mice have increased embryopathies. Thus, embryonic processes regulating the balance of ROS formation, oxidative DNA damage and repair, and ROS-mediated signal transduction may be important determinants of teratological risk

  8. Reactive oxygen species and nitric oxide signaling in bystander cells.

    Science.gov (United States)

    Jella, Kishore Kumar; Moriarty, Roisin; McClean, Brendan; Byrne, Hugh J; Lyng, Fiona M

    2018-01-01

    It is now well accepted that radiation induced bystander effects can occur in cells exposed to media from irradiated cells. The aim of this study was to follow the bystander cells in real time following addition of media from irradiated cells and to determine the effect of inhibiting these signals. A human keratinocyte cell line, HaCaT cells, was irradiated (0.005, 0.05 and 0.5 Gy) with γ irradiation, conditioned medium was harvested after one hour and added to recipient bystander cells. Reactive oxygen species, nitric oxide, Glutathione levels, caspase activation, cytotoxicity and cell viability was measured after the addition of irradiated cell conditioned media to bystander cells. Reactive oxygen species and nitric oxide levels in bystander cells treated with 0.5Gy ICCM were analysed in real time using time lapse fluorescence microscopy. The levels of reactive oxygen species were also measured in real time after the addition of extracellular signal-regulated kinase and c-Jun amino-terminal kinase pathway inhibitors. ROS and glutathione levels were observed to increase after the addition of irradiated cell conditioned media (0.005, 0.05 and 0.5 Gy ICCM). Caspase activation was found to increase 4 hours after irradiated cell conditioned media treatment (0.005, 0.05 and 0.5 Gy ICCM) and this increase was observed up to 8 hours and there after a reduction in caspase activation was observed. A decrease in cell viability was observed but no major change in cytotoxicity was found in HaCaT cells after treatment with irradiated cell conditioned media (0.005, 0.05 and 0.5 Gy ICCM). This study involved the identification of key signaling molecules such as reactive oxygen species, nitric oxide, glutathione and caspases generated in bystander cells. These results suggest a clear connection between reactive oxygen species and cell survival pathways with persistent production of reactive oxygen species and nitric oxide in bystander cells following exposure to irradiated cell

  9. Reactive oxygen species production and discontinuous gas exchange in insects

    OpenAIRE

    Boardman, Leigh; Terblanche, John S.; Hetz, Stefan K.; Marais, Elrike; Chown, Steven L.

    2011-01-01

    While biochemical mechanisms are typically used by animals to reduce oxidative damage, insects are suspected to employ a higher organizational level, discontinuous gas exchange mechanism to do so. Using a combination of real-time, flow-through respirometry and live-cell fluorescence microscopy, we show that spiracular control associated with the discontinuous gas exchange cycle (DGC) in Samia cynthia pupae is related to reactive oxygen species (ROS). Hyperoxia fails to increase mean ROS produ...

  10. HIF and reactive oxygen species regulate oxidative phosphorylation in cancer

    Czech Academy of Sciences Publication Activity Database

    Hervouet, E.; Čížková, Alena; Demont, J.; Vojtíšková, Alena; Pecina, Petr; Franssen-van Hal, N.; Keijer, J.; Simonnet, H.; Ivánek, Robert; Kmoch, S.; Godinot, C.; Houštěk, Josef

    2008-01-01

    Roč. 29, č. 8 (2008), s. 1528-1537 ISSN 0143-3334 R&D Projects: GA MŠk(CZ) 1M0520; GA ČR GA303/07/0781 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z50520514 Keywords : carcinoma * mitochondrial biogenesis * reactive oxygen species Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.930, year: 2008

  11. Targeted modulation of reactive oxygen species in the vascular endothelium

    OpenAIRE

    Shuvaev, Vladimir V.; Muzykantov, Vladimir R.

    2011-01-01

    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-mo...

  12. Mitochondria and Reactive Oxygen Species: Physiology and Pathophysiology

    Directory of Open Access Journals (Sweden)

    Subhashini Bolisetty

    2013-03-01

    Full Text Available 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.

  13. Are mitochondrial reactive oxygen species required for autophagy?

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jianfei, E-mail: jjf73@pitt.edu [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States); Maeda, Akihiro; Ji, Jing [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States); Baty, Catherine J.; Watkins, Simon C. [Center for Biologic Imaging, Department of Cell Biology and Physiology, University of Pittsburgh (United States); Greenberger, Joel S. [Department of Radiation Oncology, University of Pittsburgh (United States); Kagan, Valerian E., E-mail: kagan@pitt.edu [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States)

    2011-08-19

    Highlights: {yields} Autophageal and apoptotic pathways were dissected in cytochrome c deficient cells. {yields} Staurosporine (STS)-induced autophagy was not accompanied by ROS generation. {yields} Autophagy was detectable in mitochondrial DNA deficient {rho}{sup 0} cells. {yields} Mitochondrial ROS are not required for the STS-induced autophagy in HeLa cells. -- Abstract: Reactive oxygen species (ROS) are said to participate in the autophagy signaling. Supporting evidence is obscured by interference of autophagy and apoptosis, whereby the latter heavily relies on ROS signaling. To dissect autophagy from apoptosis we knocked down expression of cytochrome c, the key component of mitochondria-dependent apoptosis, in HeLa cells using shRNA. In cytochrome c deficient HeLa1.2 cells, electron transport was compromised due to the lack of electron shuttle between mitochondrial respiratory complexes III and IV. A rapid and robust LC3-I/II conversion and mitochondria degradation were observed in HeLa1.2 cells treated with staurosporine (STS). Neither generation of superoxide nor accumulation of H{sub 2}O{sub 2} was detected in STS-treated HeLa1.2 cells. A membrane permeable antioxidant, PEG-SOD, plus catalase exerted no effect on STS-induced LC3-I/II conversion and mitochondria degradation. Further, STS caused autophagy in mitochondria DNA-deficient {rho}{sup o} HeLa1.2 cells in which both electron transport and ROS generation were completely disrupted. Counter to the widespread view, we conclude that mitochondrial ROS are not required for the induction of autophagy.

  14. Are mitochondrial reactive oxygen species required for autophagy?

    International Nuclear Information System (INIS)

    Jiang, Jianfei; Maeda, Akihiro; Ji, Jing; Baty, Catherine J.; Watkins, Simon C.; Greenberger, Joel S.; Kagan, Valerian E.

    2011-01-01

    Highlights: → Autophageal and apoptotic pathways were dissected in cytochrome c deficient cells. → Staurosporine (STS)-induced autophagy was not accompanied by ROS generation. → Autophagy was detectable in mitochondrial DNA deficient ρ 0 cells. → Mitochondrial ROS are not required for the STS-induced autophagy in HeLa cells. -- Abstract: Reactive oxygen species (ROS) are said to participate in the autophagy signaling. Supporting evidence is obscured by interference of autophagy and apoptosis, whereby the latter heavily relies on ROS signaling. To dissect autophagy from apoptosis we knocked down expression of cytochrome c, the key component of mitochondria-dependent apoptosis, in HeLa cells using shRNA. In cytochrome c deficient HeLa1.2 cells, electron transport was compromised due to the lack of electron shuttle between mitochondrial respiratory complexes III and IV. A rapid and robust LC3-I/II conversion and mitochondria degradation were observed in HeLa1.2 cells treated with staurosporine (STS). Neither generation of superoxide nor accumulation of H 2 O 2 was detected in STS-treated HeLa1.2 cells. A membrane permeable antioxidant, PEG-SOD, plus catalase exerted no effect on STS-induced LC3-I/II conversion and mitochondria degradation. Further, STS caused autophagy in mitochondria DNA-deficient ρ o HeLa1.2 cells in which both electron transport and ROS generation were completely disrupted. Counter to the widespread view, we conclude that mitochondrial ROS are not required for the induction of autophagy.

  15. Kinetics of oxygen species in an electrically driven singlet oxygen generator

    International Nuclear Information System (INIS)

    Azyazov, V.N.; Torbin, A.P.; Pershin, A.A.; Mikheyev, P.A.; Heaven, M.C.

    2015-01-01

    Highlights: • Vibrational excitation of O_3 increases the rate constant for O_3 + O_2(a) → 2O_2(X) + O. • Vibrationally excited O_3 is produced by the O + O_2(X) + M → O_3 + M reaction. • Ozone concentrations are impacted by the reactions of vibrationally excited O_3. • Relevant to ozone concentrations in oxygen discharges and the upper atmosphere. - Abstract: The kinetics of oxygen species in the gaseous medium of a discharge singlet oxygen generator has been revisited. Vibrationally excited ozone O_3(υ) formed in O + O_2 recombination is thought to be a significant agent in the deactivation of singlet oxygen O_2(a"1Δ), oxygen atom removal and ozone formation. It is shown that the process O_3(υ ⩾ 2) + O_2(a"1Δ) → 2O_2 + O is the main O_2(a"1Δ) deactivation channel in the post-discharge zone. If no measures are taken to decrease the oxygen atom concentration, the contribution of this process to the overall O_2(a"1Δ) removal is significant, even in the discharge zone. A simplified model for the kinetics of vibrationally excited ozone is proposed. Calculations based on this model yield results that are in good agreement with the experimental data.

  16. Brain Abscess Caused by Cladophialophora Species

    Directory of Open Access Journals (Sweden)

    Sunayana. M. Jangla

    2017-10-01

    Full Text Available We report a case of 55-year-old male who presented with history of double vision on left side, slurred speech and loss of memory since a week. Computerized tomography scan was done which showed space occupying lesion in occipital region. Pus was drained by craniotomy. Histopathological examination and ten percent potassium hydroxide mount of pus showed septate dematiaceous hyphae. Culture grew dematiaceous mould which was reported as Cladophialophora species. Patient responded to surgical drainage along with voriconazole therapy.

  17. Bacteremia caused by Achromobacter species in an immunocompromised host.

    Science.gov (United States)

    Kish, M A; Buggy, B P; Forbes, B A

    1984-01-01

    A case of bacteremia caused by Achromobacter species in an immunocompromised patient is described. The patient responded to antibiotic therapy. Detailed antibiotic susceptibility data are presented. PMID:6332118

  18. Reactive oxygen species inhibit catalytic activity of peptidylarginine deiminase

    DEFF Research Database (Denmark)

    Damgaard, Dres; Bjørn, Mads Emil; Jensen, Peter Østrup

    2017-01-01

    on calcium and reducing conditions. However, reactive oxygen species (ROS) have been shown to induce citrullination of histones in granulocytes. Here we examine the ability of H2O2 and leukocyte-derived ROS to regulate PAD activity using citrullination of fibrinogen as read-out. H2O2 at concentrations above...... from stimulated leukocytes was unaffected by exogenously added H2O2 at concentrations up to 1000 µM. The role of ROS in regulating PAD activity may play an important part in preventing hypercitrullination of proteins....

  19. Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing

    OpenAIRE

    Tan, Guoxin; Wang, Shuangying; Zhu, Ye; Zhou, Lei; Yu, Peng; Wang, Xiaolan; He, Tianrui; Chen, Junqi; Mao, Chuanbin; Ning, Chengyun

    2016-01-01

    Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Conseq...

  20. (3) Melatonin Protects Oocytes and Granulosa Cells from Reactive Oxygen Species during the Ovulatory Process

    OpenAIRE

    田村, 博史; Hiroshi, TAMURA; 山口大学大学院医学系研究科産科婦人科学; Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine

    2009-01-01

    Reactive oxygen species (ROS) are produced within the follicle especially during the ovulatory process. ROS play a physiological role in the process of ovulation, e.g. follicle rapture. However, excessive amount of ROS causes oxidative stress and damages oocytes and luteinized granulosa cells. On the other hand, antioxidant defense systems including superoxide dismutase (SOD) or glutathione (GSH) are present in follicles. The balance between ROS and antioxidants within the follicle seems to b...

  1. Kinetics of oxygen species in an electrically driven singlet oxygen generator

    Energy Technology Data Exchange (ETDEWEB)

    Azyazov, V.N., E-mail: azyazov@fian.smr.ru [Samara State Aerospace University, 443086 (Russian Federation); Lebedev Physical Institute of RAS, Samara 443011 (Russian Federation); Torbin, A.P.; Pershin, A.A. [Samara State Aerospace University, 443086 (Russian Federation); Lebedev Physical Institute of RAS, Samara 443011 (Russian Federation); Mikheyev, P.A., E-mail: mikheyev@fian.smr.ru [Samara State Aerospace University, 443086 (Russian Federation); Lebedev Physical Institute of RAS, Samara 443011 (Russian Federation); Heaven, M.C., E-mail: mheaven@emory.edu [Emory University, Atlanta, GA 30322 (United States)

    2015-12-16

    Highlights: • Vibrational excitation of O{sub 3} increases the rate constant for O{sub 3} + O{sub 2}(a) → 2O{sub 2}(X) + O. • Vibrationally excited O{sub 3} is produced by the O + O{sub 2}(X) + M → O{sub 3} + M reaction. • Ozone concentrations are impacted by the reactions of vibrationally excited O{sub 3}. • Relevant to ozone concentrations in oxygen discharges and the upper atmosphere. - Abstract: The kinetics of oxygen species in the gaseous medium of a discharge singlet oxygen generator has been revisited. Vibrationally excited ozone O{sub 3}(υ) formed in O + O{sub 2} recombination is thought to be a significant agent in the deactivation of singlet oxygen O{sub 2}(a{sup 1}Δ), oxygen atom removal and ozone formation. It is shown that the process O{sub 3}(υ ⩾ 2) + O{sub 2}(a{sup 1}Δ) → 2O{sub 2} + O is the main O{sub 2}(a{sup 1}Δ) deactivation channel in the post-discharge zone. If no measures are taken to decrease the oxygen atom concentration, the contribution of this process to the overall O{sub 2}(a{sup 1}Δ) removal is significant, even in the discharge zone. A simplified model for the kinetics of vibrationally excited ozone is proposed. Calculations based on this model yield results that are in good agreement with the experimental data.

  2. Colletotrichum species causing anthracnose disease of chili in China

    NARCIS (Netherlands)

    Diao, Y.-Z.; Zhang, C.; Liu, F.; Wang, W.-Z.; Liu, L.; Cai, L.; Liu, X.-L.

    2017-01-01

    Anthracnose caused by Colletotrichum species is a serious disease of more than 30 plant genera. Several Colletotrichum species have been reported to infect chili in different countries. Although China is the largest chiliproducing country, little is known about the species that have been infecting

  3. Toxicological and pathophysiological roles of reactive oxygen and nitrogen species

    International Nuclear Information System (INIS)

    Roberts, Ruth A.; Smith, Robert A.; Safe, Stephen; Szabo, Csaba; Tjalkens, Ronald B.; Robertson, Fredika M.

    2010-01-01

    'Oxidative and Nitrative Stress in Toxicology and Disease' was the subject of a symposium held at the EUROTOX meeting in Dresden 15th September 2009. Reactive oxygen (ROS) and reactive nitrogen species (RNS) produced during tissue pathogenesis and in response to viral or chemical toxicants, induce a complex series of downstream adaptive and reparative events driven by the associated oxidative and nitrative stress. As highlighted by all the speakers, ROS and RNS can promote diverse biological responses associated with a spectrum of disorders including neurodegenerative/neuropsychiatric and cardiovascular diseases. Similar pathways are implicated during the process of liver and skin carcinogenesis. Mechanistically, reactive oxygen and nitrogen species drive sustained cell proliferation, cell death including both apoptosis and necrosis, formation of nuclear and mitochondrial DNA mutations, and in some cases stimulation of a pro-angiogenic environment. Here we illustrate the pivotal role played by oxidative and nitrative stress in cell death, inflammation and pain and its consequences for toxicology and disease pathogenesis. Examples are presented from five different perspectives ranging from in vitro model systems through to in vivo animal model systems and clinical outcomes.

  4. Reactive oxygen species in disease: Rebuttal of a conventional concept

    Directory of Open Access Journals (Sweden)

    Luis Vitetta

    2015-09-01

    Full Text Available The production of intracellular reactive oxygen species and reactive nitrogen species has long been proposed as leading to the random deleterious modification of macromolecules (i.e., nucleic acids, proteins with an associated progressive development of the age associated systemic diseases (e.g., diabetes, Parkinson’s disease as well as contributing to the ageing process.   Superoxide anion (hydrogen peroxide and nitric oxide (peroxynitrite comprise regulated intracellular second messenger pro-oxidant systems, with specific sub-cellular locales of production and are essential for the normal function of the metabolome and cellular electro-physiology.  We have posited that the formation of superoxide anion and its metabolic product hydrogen peroxide, and nitric oxide, do not conditionally lead to random damage of macromolecular species such as nucleic acids or proteins.  Under normal physiological conditions their production is intrinsically regulated that is very much consistent with their second messenger purpose of function.   We further propose that the concept of an orally administered small molecule antioxidant as a therapy to abrogate free radical activity (to control oxidative stress is a chimera.  As such we consider that free radicals are not a major overwhelming player in the development of the chronic diseases or the ageing process.

  5. [Relationship among the Oxygen Concentration, Reactive Oxygen Species and the Biological Characteristics of Mouse Bone Marrow Hematopoietic Stem Cells].

    Science.gov (United States)

    Ren, Si-Hua; He, Yu-Xin; Ma, Yi-Ran; Jin, Jing-Chun; Kang, Dan

    2016-02-01

    To investigate the effects of oxygen concentration and reactive oxygen species (ROS) on the biological characteristics of hematopoietic stem cells (HSC) and to analyzed the relationship among the oxygen concentration, ROS and the biological characteristics of mouse HSC through simulation of oxygen environment experienced by PB HSC during transplantation. The detection of reactive oxygen species (ROS), in vitro amplification, directional differentiation (BFU-E, CFU-GM, CFU-Mix), homing of adhesion molecules (CXCR4, CD44, VLA4, VLA5, P-selectin), migration rate, CFU-S of NOD/SCID mice irradiated with sublethal dose were performed to study the effect of oxgen concentration and reactive oxygen species on the biological characteristics of mouse BM-HSC and the relationship among them. The oxygen concentrations lower than normal oxygen concentration (especially hypoxic oxygen environment) could reduce ROS level and amplify more Lin(-) c-kit(+) Sca-1(+) BM HSC, which was more helpful to the growth of various colonies (BFU-E, CFU-GM, CFU-Mix) and to maintain the migratory ability of HSC, thus promoting CFU-S growth significantly after the transplantation of HSC in NOD/SCID mice irradiated by a sublethal dose. BM HSC exposed to oxygen environments of normal, inconstant oxygen level and strenuously thanging of oxygen concentration could result in higher level of ROS, at the same time, the above-mentioned features and functional indicators were relatively lower. The ROS levels of BM HSC in PB HSCT are closely related to the concentrations and stability of oxygen surrounding the cells. High oxygen concentration results in an high level of ROS, which is not helpful to maintain the biological characteristics of BM HSC. Before transplantation and in vitro amplification, the application of antioxidancs and constant oxygen level environments may be beneficial for transplantation of BMMSC.

  6. The bystander effect: is reactive oxygen species the driver?

    International Nuclear Information System (INIS)

    Szumiel, I.

    2003-01-01

    The paper reviews selected examples of the bystander effect, such as clonogenic survival decrease, chromosomal aberrations and mutations. The similarities and differences between the biological effects in directly targeted and bystander cells are briefly discussed. Also reviewed are the experimental data which support the role of reactive oxygen species (ROS), especially *O 2 - , as mediators of the bystander effect. Endogenously generated ROS, due to activation of NAD(P)H oxidases, play a kay role in the introduction of DNA damage in bystander cells. All the observed effects in bystander cells, such as alteration in gene expression patterns, chromosomal aberrations, sister chromatid exchanges, mutations, genome instability and neoplastic transformation are the consequence of DNA damage. (author)

  7. Mechanisms of nanotoxicity: Generation of reactive oxygen species

    Directory of Open Access Journals (Sweden)

    Peter P. Fu

    2014-03-01

    Full Text Available Nanotechnology is a rapidly developing field in the 21st century, and the commercial use of nanomaterials for novel applications is increasing exponentially. To date, the scientific basis for the cytotoxicity and genotoxicity of most manufactured nanomaterials are not understood. The mechanisms underlying the toxicity of nanomaterials have recently been studied intensively. An important mechanism of nanotoxicity is the generation of reactive oxygen species (ROS. Overproduction of ROS can induce oxidative stress, resulting in cells failing to maintain normal physiological redox-regulated functions. This in turn leads to DNA damage, unregulated cell signaling, change in cell motility, cytotoxicity, apoptosis, and cancer initiation. There are critical determinants that can affect the generation of ROS. These critical determinants, discussed briefly here, include: size, shape, particle surface, surface positive charges, surface-containing groups, particle dissolution, metal ion release from nanometals and nanometal oxides, UV light activation, aggregation, mode of interaction with cells, inflammation, and pH of the medium.

  8. Endogenous mechanisms of reactive oxygen species (ROS generation

    Directory of Open Access Journals (Sweden)

    Agata Sarniak

    2016-11-01

    Full Text Available The main cellular source of reactive oxygen species (ROS is mitochondrial respiratory chain and active NADPH responsible for “respiratory burst” of phagocytes. Whatsmore ROS are produced in endoplasmic reticulum, peroxisomes, with the participation of xanthine and endothelial oxidase and during autoxidation process of small molecules. Mitochondrial respiratory chain is the main cellular source of ROS. It is considered that in aerobic organisms ROS are mainly formed during normal oxygen metabolism, as byproducts of oxidative phosphorylation, during the synthesis of ATP. The intermembranous phagocyte enzyme – activated NADPH oxidase, responsible for the “respiratory burst” of phagocytes, which is another source of ROS, plays an important role in defense of organism against infections.The aim of this article is to resume actuall knowledge about structure and function of the mitochondrial electron transport chain in which ROS are the byproducts and about NADPH oxidase as well as the function of each of its components in the “respiratory burst” of phagocytes.

  9. Are mitochondria a permanent source of reactive oxygen species?

    Science.gov (United States)

    Staniek, K; Nohl, H

    2000-11-20

    The observation that in isolated mitochondria electrons may leak out of the respiratory chain to form superoxide radicals (O(2)(radical-)) has prompted the assumption that O(2)(radical-) formation is a compulsory by-product of respiration. Since mitochondrial O(2)(radical-) formation under homeostatic conditions could not be demonstrated in situ so far, conclusions drawn from isolated mitochondria must be considered with precaution. The present study reveals a link between electron deviation from the respiratory chain to oxygen and the coupling state in the presence of antimycin A. Another important factor is the analytical system applied for the detection of activated oxygen species. Due to the presence of superoxide dismutase in mitochondria, O(2)(radical-) release cannot be realistically determined in intact mitochondria. We therefore followed the release of the stable dismutation product H(2)O(2) by comparing most frequently used H(2)O(2) detection methods. The possible interaction of the detection systems with the respiratory chain was avoided by a recently developed method, which was compared with conventional methods. Irrespective of the methods applied, the substrates used for respiration and the state of respiration established, intact mitochondria could not be made to release H(2)O(2) from dismutating O(2)(radical-). Although regular mitochondrial respiration is unlikely to supply single electrons for O(2)(radical-) formation our study does not exclude the possibility of the respiratory chain becoming a radical source under certain conditions.

  10. Photosensitizing Nanoparticles and The Modulation of Reactive Oxygen Species generation

    Directory of Open Access Journals (Sweden)

    Dayane Batista Tada

    2015-05-01

    Full Text Available The association of PhotoSensitizer (PS molecules with nanoparticles (NPs forming photosensitizing NPs, has emerged as a therapeutic strategy to improve PS tumor targeting, to protect PS from deactivation reactions and to enhance both PS solubility and circulation time. Since association with NPs usually alters PS photophysical and photochemical properties, photosensitizing NPs are an important tool to modulate reactive oxygen species (ROS generation. Depending on the design of the photosensitizing NP, i.e., type of PS, the NP material and the method applied for the construction of the photosensitizing NP, the deactivation routes of the excited state can be controlled, allowing the generation of either singlet oxygen or other ROS. Controlling the type of generated ROS is desirable not only in biomedical applications, as in Photodynamic Therapy where the type of ROS affects therapeutic efficiency, but also in other technological relevant fields like energy conversion, where the electron and energy transfer processes are necessary to increase the efficiency of photoconversion cells. The current review highlights some of the recent developments in the design of Photosensitizing NPs aimed at modulating the primary photochemical events after light absorption.

  11. Mechanism of artemisinin phytotoxicity action: induction of reactive oxygen species and cell death in lettuce seedlings.

    Science.gov (United States)

    Yan, Zhi-Qiang; Wang, Dan-Dan; Ding, Lan; Cui, Hai-Yan; Jin, Hui; Yang, Xiao-Yan; Yang, Jian-She; Qin, Bo

    2015-03-01

    Artemisinin has been recognized as an allelochemical that inhibits growth of several plant species. However, its mode of action is not well clarified. In this study, the mechanism of artemisinin phytotoxicity on lettuce seedlings was investigated. Root and shoot elongation of lettuce seedlings were inhibited by artemisinin in a concentration-dependent manner. The compound effectively arrested cell division and caused loss of cell viability in root tips of lettuce. Overproduction of reactive oxygen species (ROS) was induced by artemisinin. Lipid peroxidation, proline overproduction and reduction of chlorophyll content in lettuce seedlings were found after treatments. These results suggested that artemisinin could induce ROS overproduction, which caused membrane lipids peroxidation and cell death, and impacted mitosis and physiological processes, resulting in growth inhibition of receptor plants. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  12. Reactive oxygen species, essential molecules, during plant-pathogen interactions.

    Science.gov (United States)

    Camejo, Daymi; Guzmán-Cedeño, Ángel; Moreno, Alexander

    2016-06-01

    Reactive oxygen species (ROS) are continually generated as a consequence of the normal metabolism in aerobic organisms. Accumulation and release of ROS into cell take place in response to a wide variety of adverse environmental conditions including salt, temperature, cold stresses and pathogen attack, among others. In plants, peroxidases class III, NADPH oxidase (NOX) locates in cell wall and plasma membrane, respectively, may be mainly enzymatic systems involving ROS generation. It is well documented that ROS play a dual role into cells, acting as important signal transduction molecules and as toxic molecules with strong oxidant power, however some aspects related to its function during plant-pathogen interactions remain unclear. This review focuses on the principal enzymatic systems involving ROS generation addressing the role of ROS as signal molecules during plant-pathogen interactions. We described how the chloroplasts, mitochondria and peroxisomes perceive the external stimuli as pathogen invasion, and trigger resistance response using ROS as signal molecule. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  13. REACTIVE OXYGEN SPECIES AT THE CROSSROADS OF INFLAMMASOME AND INFLAMMATION

    Directory of Open Access Journals (Sweden)

    Anantha eHarijith

    2014-09-01

    Full Text Available Inflammasomes form a crucial part of the innate immune system. These are multi-protein oligomer platforms that are composed of intracellular sensors which are coupled with caspase and interleukin activating systems. Nod-like receptor protein (NLRP 3, and 6 and NLRC4 and AIM2 are the prominent members of the inflammasome family. Inflammasome activation leads to pyroptosis, a process of programmed cell death distinct from apoptosis through activation of Caspase and further downstream targets such as IL-1β and IL-18 leading to activation of inflammatory cascade. Reactive oxygen species (ROS serve as important inflammasome activating signals. ROS activate inflammasome through mitogen-activated protein kinases (MAPK and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2. Dysregulation of inflammasome is plays a significant role in various pathological process. Viral infections such as Dengue and Respiratory syncytial virus activate inflammasomes. Crystal compounds in silicosis and gout also activate ROS. In diabetes, inhibition of autophagy with resultant accumulation of dysfunctional mitochondria leads to enhanced ROS production activating inflammasomes. Activation of inflammasomes can be dampened by antioxidants such as SIRT-1. Inflammasome and related cascade could serve as future therapeutic targets for various pathological conditions.

  14. Reactive oxygen species (ROS) and cancer: Role of antioxidative nutraceuticals.

    Science.gov (United States)

    Prasad, Sahdeo; Gupta, Subash C; Tyagi, Amit K

    2017-02-28

    Extensive research over the past half a century indicates that reactive oxygen species (ROS) play an important role in cancer. Although low levels of ROS can be beneficial, excessive accumulation can promote cancer. One characteristic of cancer cells that distinguishes them from normal cells is their ability to produce increased numbers of ROS and their increased dependence on an antioxidant defense system. ROS are produced as a byproduct intracellularly by mitochondria and other cellular elements and exogenously by pollutants, tobacco, smoke, drugs, xenobiotics, and radiation. ROS modulate various cell signaling pathways, which are primarily mediated through the transcription factors NF-κB and STAT3, hypoxia-inducible factor-1α, kinases, growth factors, cytokines and other proteins, and enzymes; these pathways have been linked to cellular transformation, inflammation, tumor survival, proliferation, invasion, angiogenesis, and metastasis of cancer. ROS are also associated with epigenetic changes in genes, which is helpful in diagnosing diseases. This review considers the role of ROS in the various stages of cancer development. Finally, we provide evidence that nutraceuticals derived from Mother Nature are highly effective in eliminating cancer cells. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Use the Protonmotive Force: Mitochondrial Uncoupling and Reactive Oxygen Species.

    Science.gov (United States)

    Berry, Brandon J; Trewin, Adam J; Amitrano, Andrea M; Kim, Minsoo; Wojtovich, Andrew P

    2018-04-04

    Mitochondrial respiration results in an electrochemical proton gradient, or protonmotive force (pmf), across the mitochondrial inner membrane. The pmf is a form of potential energy consisting of charge (∆ψ m ) and chemical (∆pH) components, that together drive ATP production. In a process called uncoupling, proton leak into the mitochondrial matrix independent of ATP production dissipates the pmf and energy is lost as heat. Other events can directly dissipate the pmf independent of ATP production as well, such as chemical exposure or mechanisms involving regulated mitochondrial membrane electrolyte transport. Uncoupling has defined roles in metabolic plasticity and can be linked through signal transduction to physiologic events. In the latter case, the pmf impacts mitochondrial reactive oxygen species (ROS) production. Although capable of molecular damage, ROS also have signaling properties that depend on the timing, location, and quantity of their production. In this review, we provide a general overview of mitochondrial ROS production, mechanisms of uncoupling, and how these work in tandem to affect physiology and pathologies, including obesity, cardiovascular disease, and immunity. Overall, we highlight that isolated bioenergetic models-mitochondria and cells-only partially recapitulate the complex link between the pmf and ROS signaling that occurs in vivo. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Targeted modulation of reactive oxygen species in the vascular endothelium.

    Science.gov (United States)

    Shuvaev, Vladimir V; Muzykantov, Vladimir R

    2011-07-15

    '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 H(2)O(2). 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. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Mechanisms of nanotoxicity: generation of reactive oxygen species.

    Science.gov (United States)

    Fu, Peter P; Xia, Qingsu; Hwang, Huey-Min; Ray, Paresh C; Yu, Hongtao

    2014-03-01

    Nanotechnology is a rapidly developing field in the 21(st) century, and the commercial use of nanomaterials for novel applications is increasing exponentially. To date, the scientific basis for the cytotoxicity and genotoxicity of most manufactured nanomaterials are not understood. The mechanisms underlying the toxicity of nanomaterials have recently been studied intensively. An important mechanism of nanotoxicity is the generation of reactive oxygen species (ROS). Overproduction of ROS can induce oxidative stress, resulting in cells failing to maintain normal physiological redox-regulated functions. This in turn leads to DNA damage, unregulated cell signaling, change in cell motility, cytotoxicity, apoptosis, and cancer initiation. There are critical determinants that can affect the generation of ROS. These critical determinants, discussed briefly here, include: size, shape, particle surface, surface positive charges, surface-containing groups, particle dissolution, metal ion release from nanometals and nanometal oxides, UV light activation, aggregation, mode of interaction with cells, inflammation, and pH of the medium. Copyright © 2014. Published by Elsevier B.V.

  18. Salicylic acid signaling inhibits apoplastic reactive oxygen species signaling.

    Science.gov (United States)

    Xu, Enjun; Brosché, Mikael

    2014-06-04

    Reactive oxygen species (ROS) are used by plants as signaling molecules during stress and development. Given the amount of possible challenges a plant face from their environment, plants need to activate and prioritize between potentially conflicting defense signaling pathways. Until recently, most studies on signal interactions have focused on phytohormone interaction, such as the antagonistic relationship between salicylic acid (SA)-jasmonic acid and cytokinin-auxin. In this study, we report an antagonistic interaction between SA signaling and apoplastic ROS signaling. Treatment with ozone (O3) leads to a ROS burst in the apoplast and induces extensive changes in gene expression and elevation of defense hormones. However, Arabidopsis thaliana dnd1 (defense no death1) exhibited an attenuated response to O3. In addition, the dnd1 mutant displayed constitutive expression of defense genes and spontaneous cell death. To determine the exact process which blocks the apoplastic ROS signaling, double and triple mutants involved in various signaling pathway were generated in dnd1 background. Simultaneous elimination of SA-dependent and SA-independent signaling components from dnd1 restored its responsiveness to O3. Conversely, pre-treatment of plants with SA or using mutants that constitutively activate SA signaling led to an attenuation of changes in gene expression elicited by O3. Based upon these findings, we conclude that plants are able to prioritize the response between ROS and SA via an antagonistic action of SA and SA signaling on apoplastic ROS signaling.

  19. Light irradiation helps magnetotactic bacteria eliminate intracellular reactive oxygen species.

    Science.gov (United States)

    Li, Kefeng; Wang, Pingping; Chen, Chuanfang; Chen, Changyou; Li, Lulu; Song, Tao

    2017-09-01

    Magnetotactic bacteria (MTB) demonstrate photoresponse. However, little is known about the biological significance of this behaviour. Magnetosomes exhibit peroxidase-like activity and can scavenge reactive oxygen species (ROS). Magnetosomes extracted from the Magnetospirillum magneticum strain AMB-1 show enhanced peroxidase-like activity under illumination. The present study investigated the effects of light irradiation on nonmagnetic (without magnetosomes) and magnetic (with magnetosomes) AMB-1 cells. Results showed that light irradiation did not affect the growth of nonmagnetic and magnetic cells but significantly increased magnetosome synthesis and reduced intracellular ROS level in magnetic cells. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to analyse the expression level of magnetosome formation-associated genes (mamA, mms6, mms13 and mmsF) and stress-related genes (recA, oxyR, SOD, amb0664 and amb2684). Results showed that light irradiation upregulated the expression of mms6, mms13 and mmsF. Furthermore, light irradiation upregulated the expression of stress-related genes in nonmagnetic cells but downregulated them in magnetic cells. Additionally, magnetic cells exhibited stronger phototactic behaviour than nonmagnetic ones. These results suggested that light irradiation could heighten the ability of MTB to eliminate intracellular ROS and help them adapt to lighted environments. This phenomenon may be related to the enhanced peroxidase-like activity of magnetosomes under light irradiation. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Matairesinol inhibits angiogenesis via suppression of mitochondrial reactive oxygen species

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Boram; Kim, Ki Hyun; Jung, Hye Jin [Chemical Genomics National Research Laboratory, Department of Biotechnology, Translational Research Center for Protein Function Control, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Kwon, Ho Jeong, E-mail: kwonhj@yonsei.ac.kr [Chemical Genomics National Research Laboratory, Department of Biotechnology, Translational Research Center for Protein Function Control, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2012-04-27

    Highlights: Black-Right-Pointing-Pointer Matairesinol suppresses mitochondrial ROS generation during hypoxia. Black-Right-Pointing-Pointer Matairesinol exhibits potent anti-angiogenic activity both in vitro and in vivo. Black-Right-Pointing-Pointer Matairesinol could be a basis for the development of novel anti-angiogenic agents. -- Abstract: 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{alpha} in hypoxic HeLa cells. These results demonstrate that matairesinol could function as a novel angiogenesis inhibitor by suppressing mROS signaling.

  1. Pleiotropic Effects of Biguanides on Mitochondrial Reactive Oxygen Species Production

    Directory of Open Access Journals (Sweden)

    Alena Pecinova

    2017-01-01

    Full Text Available Metformin is widely prescribed as a first-choice antihyperglycemic drug for treatment of type 2 diabetes mellitus, and recent epidemiological studies showed its utility also in cancer therapy. Although it is in use since the 1970s, its molecular target, either for antihyperglycemic or antineoplastic action, remains elusive. However, the body of the research on metformin effect oscillates around mitochondrial metabolism, including the function of oxidative phosphorylation (OXPHOS apparatus. In this study, we focused on direct inhibitory mechanism of biguanides (metformin and phenformin on OXPHOS complexes and its functional impact, using the model of isolated brown adipose tissue mitochondria. We demonstrate that biguanides nonspecifically target the activities of all respiratory chain dehydrogenases (mitochondrial NADH, succinate, and glycerophosphate dehydrogenases, but only at very high concentrations (10−2–10−1 M that highly exceed cellular concentrations observed during the treatment. In addition, these concentrations of biguanides also trigger burst of reactive oxygen species production which, in combination with pleiotropic OXPHOS inhibition, can be toxic for the organism. We conclude that the beneficial effect of biguanides should probably be associated with subtler mechanism, different from the generalized inhibition of the respiratory chain.

  2. Role of Melanin in Melanocyte Dysregulation of Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Noah C. Jenkins

    2013-01-01

    Full Text Available We have recently reported a potential alternative tumor suppressor function for p16 relating to its capacity to regulate oxidative stress and observed that oxidative dysregulation in p16-depleted cells was most profound in melanocytes, compared to keratinocytes or fibroblasts. Moreover, in the absence of p16 depletion or exogenous oxidative insult, melanocytes exhibited significantly higher basal levels of reactive oxygen species (ROS than these other epidermal cell types. Given the role of oxidative stress in melanoma development, we speculated that this increased susceptibility of melanocytes to oxidative stress (and greater reliance on p16 for suppression of ROS may explain why genetic compromise of p16 is more commonly associated with predisposition to melanoma rather than other cancers. Here we show that the presence of melanin accounts for this differential oxidative stress in normal and p16-depleted melanocytes. Thus the presence of melanin in the skin appears to be a double-edged sword: it protects melanocytes as well as neighboring keratinocytes in the skin through its capacity to absorb UV radiation, but its synthesis in melanocytes results in higher levels of intracellular ROS that may increase melanoma susceptibility.

  3. Mitochondrial Reactive Oxygen Species Trigger Hypoxia-Induced Transcription

    Science.gov (United States)

    Chandel, N. S.; Maltepe, E.; Goldwasser, E.; Mathieu, C. E.; Simon, M. C.; Schumacker, P. T.

    1998-09-01

    Transcriptional activation of erythropoietin, glycolytic enzymes, and vascular endothelial growth factor occurs during hypoxia or in response to cobalt chloride (CoCl2) in Hep3B cells. However, neither the mechanism of cellular O2 sensing nor that of cobalt is fully understood. We tested whether mitochondria act as O2 sensors during hypoxia and whether hypoxia and cobalt activate transcription by increasing generation of reactive oxygen species (ROS). Results show (i) wild-type Hep3B cells increase ROS generation during hypoxia (1.5% O2) or CoCl2 incubation, (ii) Hep3B cells depleted of mitochondrial DNA (ρ 0 cells) fail to respire, fail to activate mRNA for erythropoietin, glycolytic enzymes, or vascular endothelial growth factor during hypoxia, and fail to increase ROS generation during hypoxia; (iii) ρ 0 cells increase ROS generation in response to CoCl2 and retain the ability to induce expression of these genes; and (iv) the antioxidants pyrrolidine dithiocarbamate and ebselen abolish transcriptional activation of these genes during hypoxia or CoCl2 in wild-type cells, and abolish the response to CoCl2 in ρ 0 cells. Thus, hypoxia activates transcription via a mitochondria-dependent signaling process involving increased ROS, whereas CoCl2 activates transcription by stimulating ROS generation via a mitochondria-independent mechanism.

  4. Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing.

    Science.gov (United States)

    Tan, Guoxin; Wang, Shuangying; Zhu, Ye; Zhou, Lei; Yu, Peng; Wang, Xiaolan; He, Tianrui; Chen, Junqi; Mao, Chuanbin; Ning, Chengyun

    2016-09-21

    Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Consequently, the bacteria are selectively killed on the cathode surface. However, the cell experiment suggested that the level of ROS is safe for normal mammalian cells.

  5. Colletotrichum species causing anthracnose disease of chili in China.

    Science.gov (United States)

    Diao, Y-Z; Zhang, C; Liu, F; Wang, W-Z; Liu, L; Cai, L; Liu, X-L

    2017-06-01

    Anthracnose caused by Colletotrichum species is a serious disease of more than 30 plant genera. Several Colletotrichum species have been reported to infect chili in different countries. Although China is the largest chili-producing country, little is known about the species that have been infecting chili locally. Therefore, we collected samples of diseased chili from 29 provinces of China, from which 1285 strains were isolated. The morphological characters of all strains were observed and compared, and multi-locus phylogenetic analyses (ITS, ACT , CAL , CHS-1 , GAPDH , TUB2 , and HIS3 ) were performed on selected representative strains. Fifteen Colletotrichum species were identified, with C. fioriniae , C. fructicola , C. gloeosporioides , C. scovillei , and C. truncatum being prevalent. Three new species, C. conoides , C. grossum , and C. liaoningense , were recognised and described in this paper. Colletotrichum aenigma , C. cliviae , C. endophytica , C. hymenocallidis , C. incanum , C. karstii , and C. viniferum were reported for the first time from chili. Pathogenicity of all species isolated from chili was confirmed, except for C. endophytica . The current study improves the understanding of species causing anthracnose on chili and provides useful information for the effective control of the disease in China.

  6. Effects of the Oxygenation level on Formation of Different Reactive Oxygen Species During Photodynamic Therapy

    OpenAIRE

    Price, Michael; Heilbrun, Lance; Kessel, David

    2013-01-01

    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 photokilli...

  7. Latitudinal shifts of introduced species: possible causes and implications

    Science.gov (United States)

    Qinfeng Guo; Dov F. Sax; Hong Qian; Regan Early

    2012-01-01

    This study aims to document shifts in the latitudinal distributions of non-native species relative to their own native distributions and to discuss possible causes and implications of these shifts. We used published and newly compiled data on intercontinentally introduced birds, mammals and plants. We found strong correlations between the latitudinal distributions...

  8. Waterborne Exophiala species causing disease in cold-blooded animals

    NARCIS (Netherlands)

    de Hoog, G.S.; Vicente, V.A.; Najafzadeh, M.J.; Harrak, M.J.; Badali, H.; Seyedmousavi, S.

    2011-01-01

    The majority of mesophilic waterborne species of the black yeast genus Exophiala (Chaetothyriales) belong to a single clade judging from SSU rDNA data. Most taxa are also found to cause cutaneous or disseminated infections in cold-blooded, water animals, occasionally reaching epidemic proportions.

  9. Waterborne Exophiala species causing disease in cold-blooded animals

    NARCIS (Netherlands)

    de Hoog, G.S.; Vicente, V.A.; Najafzadeh, M.J.; Harrak, M.J.; Badali, H.; Seyedmousavi, S.

    2012-01-01

    The majority of mesophilic waterborne species of the black yeast genus Exophiala (Chaetothyriales) belong to a single clade judging from SSU rDNA data. Most taxa are also found to cause cutaneous or disseminated infections in cold-blooded, water animals, occasionally reaching epidemic proportions.

  10. Chilli anthracnose disease caused by Colletotrichum species§

    Science.gov (United States)

    Than, Po Po; Prihastuti, Haryudian; Phoulivong, Sitthisack; Taylor, Paul W.J.; Hyde, Kevin D.

    2008-01-01

    Anthracnose disease is one of the major economic constraints to chilli production worldwide, especially in tropical and subtropical regions. Accurate taxonomic information is necessary for effective disease control management. In the Colletotrichum patho-system, different Colletotrichum species can be associated with anthracnose of the same host. Little information is known concerning the interactions of the species associated with the chilli anthracnose although several Colletotrichum species have been reported as causal agents of chilli anthracnose disease worldwide. The ambiguous taxonomic status of Colletotrichum species has resulted in inaccurate identification which may cause practical problems in plant breeding and disease management. Although the management and control of anthracnose disease are still being extensively researched, commercial cultivars of Capsicum annuum that are resistant to the pathogens that cause chilli anthracnose have not yet been developed. This paper reviews the causal agents of chilli anthracnose, the disease cycle, conventional methods in identification of the pathogen and molecular approaches that have been used for the identification of Colletotrichum species. Pathogenetic variation and population structure of the causal agents of chilli anthracnose along with the current taxonomic status of Colletotrichum species are discussed. Future developments leading to the disease management strategies are suggested. PMID:18837103

  11. Growth enhancement and gene expression of Arabidopsis thaliana irradiated with active oxygen species

    Science.gov (United States)

    Watanabe, Satoshi; Ono, Reoto; Hayashi, Nobuya; Shiratani, Masaharu; Tashiro, Kosuke; Kuhara, Satoru; Inoue, Asami; Yasuda, Kaori; Hagiwara, Hiroko

    2016-07-01

    The characteristics of plant growth enhancement effect and the mechanism of the enhancement induced by plasma irradiation are investigated using various active species in plasma. Active oxygen species in oxygen plasma are effective for growth enhancement of plants. DNA microarray analysis of Arabidopsis thaliana indicates that the genes coding proteins that counter oxidative stresses by eliminating active oxygen species are expressed at significantly high levels. The size of plant cells increases owing to oxygen plasma irradiation. The increases in gene expression levels and cell size suggest that the increase in the expression level of the expansin protein is essential for plant growth enhancement phenomena.

  12. Combined application of XANES and XPS to study oxygen species adsorbed on Ag foil

    CERN Document Server

    Bukhtiyarov, V I; Kaichev, V V; Knop-Gericke, A; Mayer, R W; Schloegl, R

    2001-01-01

    Adsorbed oxygen species realized in the course of ethylene epoxidation over polycrystalline silver have been characterized by X-ray absorption near the edge structure and X-ray photoelectron spectroscopy. Namely, the combined application of XANES and XPS in similar UHV conditions using the same sample allowed us to assign an XAS feature to the nucleophilic and electrophilic oxygen. This is of great significance, since these species are suggested to be included into the active center for ethylene epoxidation. The differences in the oxygen-silver bonding of these oxygen species are discussed.

  13. Free radicals, reactive oxygen species, oxidative stress and its classification.

    Science.gov (United States)

    Lushchak, Volodymyr I

    2014-12-05

    Reactive oxygen species (ROS) initially considered as only damaging agents in living organisms further were found to play positive roles also. This paper describes ROS homeostasis, principles of their investigation and technical approaches to investigate ROS-related processes. Especial attention is paid to complications related to experimental documentation of these processes, their diversity, spatiotemporal distribution, relationships with physiological state of the organisms. Imbalance between ROS generation and elimination in favor of the first with certain consequences for cell physiology has been called "oxidative stress". Although almost 30years passed since the first definition of oxidative stress was introduced by Helmut Sies, to date we have no accepted classification of oxidative stress. In order to fill up this gape here classification of oxidative stress based on its intensity is proposed. Due to that oxidative stress may be classified as basal oxidative stress (BOS), low intensity oxidative stress (LOS), intermediate intensity oxidative stress (IOS), and high intensity oxidative stress (HOS). Another classification of potential interest may differentiate three categories such as mild oxidative stress (MOS), temperate oxidative stress (TOS), and finally severe (strong) oxidative stress (SOS). Perspective directions of investigations in the field include development of sophisticated classification of oxidative stresses, accurate identification of cellular ROS targets and their arranged responses to ROS influence, real in situ functions and operation of so-called "antioxidants", intracellular spatiotemporal distribution and effects of ROS, deciphering of molecular mechanisms responsible for cellular response to ROS attacks, and ROS involvement in realization of normal cellular functions in cellular homeostasis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Emergence of unusual species of enterococci causing infections, South India

    Directory of Open Access Journals (Sweden)

    Rao Sambasiva R

    2005-03-01

    Full Text Available Abstract Background Enterococci tend to be one of the leading causes of nosocomial infections, with E. faecalis and E. faecium accounting up to 90% of the clinical isolates. Nevertheless, the incidence of other species of enterococci from clinical sources shows an alarming increase with the properties of intrinsic resistance to several antibiotics including beta-lactams and glycopeptides. Thus proper identification of enterococci to species level is quintessential for management and prevention of these bacteria in any healthcare facility. Hence this work was undertaken to study the prevalence of unusual species of enterococci causing human infections, in a tertiary care hospital in South India. Methods The study was conducted in a tertiary care hospital in South India from July 2001 to June 2003. Isolates of enterococci were collected from various clinical specimens and speciated using extensive phenotypic and physiological tests. Antimicrobial susceptibility testing were performed and interpreted as per NCCLS guidelines. Whole cell protein (WCP fingerprinting of enterococci were done for species validation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE and analyzed computationally. Results Our study showed the prevalence of unusual (non-faecalis and non-faecium enterococci and atypical (biochemical variant species of enterococci as 19% (46 isolates and 5% (12 isolates respectively. The 7 unusual species (46 isolates isolated and confirmed by phenotypic characterization includes: 15 E. gallinarum (6.2%, 10 E. avium (4.1%, 6 E. raffinosus (2.5%, 6 E. hirae (2.5%, 4 E. mundtii (1.7%, 3 E. casseliflavus-including the two atypical isolates (1.2% and 2 E. durans (0.8%. The 12 atypical enterococcal species (5% that showed aberrant sugar reactions in conventional phenotyping were confirmed as E. faecalis, E. faecium and E. casseliflavus respectively by WCP fingerprinting. The antimicrobial susceptibility testing depicted the

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

    Science.gov (United States)

    Price, Michael; Heilbrun, Lance; Kessel, David

    2013-01-01

    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. © 2013 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2013 The American Society of Photobiology.

  16. Effects of oxygen on responses to heating in two lizard species sampled along an elevational gradient.

    Science.gov (United States)

    DuBois, P Mason; Shea, Tanner K; Claunch, Natalie M; Taylor, Emily N

    2017-08-01

    Thermal tolerance is an important variable in predictive models about the effects of global climate change on species distributions, yet the physiological mechanisms responsible for reduced performance at high temperatures in air-breathing vertebrates are not clear. We conducted an experiment to examine how oxygen affects three variables exhibited by ectotherms as they heat-gaping threshold, panting threshold, and loss of righting response (the latter indicating the critical thermal maximum)-in two lizard species along an elevational (and therefore environmental oxygen partial pressure) gradient. Oxygen partial pressure did not impact these variables in either species. We also exposed lizards at each elevation to severely hypoxic gas to evaluate their responses to hypoxia. Severely low oxygen partial pressure treatments significantly reduced the gaping threshold, panting threshold, and critical thermal maximum. Further, under these extreme hypoxic conditions, these variables were strongly and positively related to partial pressure of oxygen. In an elevation where both species overlapped, the thermal tolerance of the high elevation species was less affected by hypoxia than that of the low elevation species, suggesting the high elevation species may be adapted to lower oxygen partial pressures. In the high elevation species, female lizards had higher thermal tolerance than males. Our data suggest that oxygen impacts the thermal tolerance of lizards, but only under severely hypoxic conditions, possibly as a result of hypoxia-induced anapyrexia. Copyright © 2017. Published by Elsevier Ltd.

  17. Rhinocerebrocutaneous mucormycosis caused by Mucor species: A rare causation

    Directory of Open Access Journals (Sweden)

    Snehal Balvant Lunge

    2015-01-01

    Full Text Available Rhinocerebral mucormycosis is the most common form of mucormycosis occurring commonly in patients of diabetic ketoacidosis. Fungi of the order Mucorales belong to six families, among whom Rhizopus is the most common, while Mucor is a rare cause. We report a 45-year-old female with uncontrolled diabetes mellitus diagnosed to have rhinocerebrocutaneous mucormycosis caused by Mucor species. The diagnosis was confirmed on histology and culture. A high-index of suspicion is required for early diagnosis and timely initiation of therapy to optimize the outcome. Our patient succumbed to her infection.

  18. Contribution of reactive oxygen species to the pathogenesis of pulmonary arterial hypertension

    Science.gov (United States)

    Naik, Jay S.; Weise-Cross, Laura; Detweiler, Neil D.; Herbert, Lindsay M.; Yellowhair, Tracylyn R.; Resta, Thomas C.

    2017-01-01

    Pulmonary arterial hypertension is associated with a decreased antioxidant capacity. However, neither the contribution of reactive oxygen species to pulmonary vasoconstrictor sensitivity, nor the therapeutic efficacy of antioxidant strategies in this setting are known. We hypothesized that reactive oxygen species play a central role in mediating both vasoconstrictor and arterial remodeling components of severe pulmonary arterial hypertension. We examined the effect of the chemical antioxidant, TEMPOL, on right ventricular systolic pressure, vascular remodeling, and enhanced vasoconstrictor reactivity in both chronic hypoxia and hypoxia/SU5416 rat models of pulmonary hypertension. SU5416 is a vascular endothelial growth factor receptor antagonist and the combination of chronic hypoxia/SU5416 produces a model of severe pulmonary arterial hypertension with vascular plexiform lesions/fibrosis that is not present with chronic hypoxia alone. The major findings from this study are: 1) compared to hypoxia alone, hypoxia/SU5416 exposure caused more severe pulmonary hypertension, right ventricular hypertrophy, adventitial lesion formation, and greater vasoconstrictor sensitivity through a superoxide and Rho kinase-dependent Ca2+ sensitization mechanism. 2) Chronic hypoxia increased medial muscularization and superoxide levels, however there was no effect of SU5416 to augment these responses. 3) Treatment with TEMPOL decreased right ventricular systolic pressure in both hypoxia and hypoxia/SU5416 groups. 4) This effect of TEMPOL was associated with normalization of vasoconstrictor responses, but not arterial remodeling. Rather, medial hypertrophy and adventitial fibrotic lesion formation were more pronounced following chronic TEMPOL treatment in hypoxia/SU5416 rats. Our findings support a major role for reactive oxygen species in mediating enhanced vasoconstrictor reactivity and pulmonary hypertension in both chronic hypoxia and hypoxia/SU5416 rat models, despite a

  19. Lycopene cyclase paralog CruP protects against reactive oxygen species in oxygenic photosynthetic organisms.

    Science.gov (United States)

    Bradbury, Louis M T; Shumskaya, Maria; Tzfadia, Oren; Wu, Shi-Biao; Kennelly, Edward J; Wurtzel, Eleanore T

    2012-07-03

    In photosynthetic organisms, carotenoids serve essential roles in photosynthesis and photoprotection. A previous report designated CruP as a secondary lycopene cyclase involved in carotenoid biosynthesis [Maresca J, et al. (2007) Proc Natl Acad Sci USA 104:11784-11789]. However, we found that cruP KO or cruP overexpression plants do not exhibit correspondingly reduced or increased production of cyclized carotenoids, which would be expected if CruP was a lycopene cyclase. Instead, we show that CruP aids in preventing accumulation of reactive oxygen species (ROS), thereby reducing accumulation of β-carotene-5,6-epoxide, a ROS-catalyzed autoxidation product, and inhibiting accumulation of anthocyanins, which are known chemical indicators of ROS. Plants with a nonfunctional cruP accumulate substantially higher levels of ROS and β-carotene-5,6-epoxide in green tissues. Plants overexpressing cruP show reduced levels of ROS, β-carotene-5,6-epoxide, and anthocyanins. The observed up-regulation of cruP transcripts under photoinhibitory and lipid peroxidation-inducing conditions, such as high light stress, cold stress, anoxia, and low levels of CO(2), fits with a role for CruP in mitigating the effects of ROS. Phylogenetic distribution of CruP in prokaryotes showed that the gene is only present in cyanobacteria that live in habitats characterized by large variation in temperature and inorganic carbon availability. Therefore, CruP represents a unique target for developing resilient plants and algae needed to supply food and biofuels in the face of global climate change.

  20. Photo-excitation of carotenoids causes cytotoxicity via singlet oxygen production

    International Nuclear Information System (INIS)

    Yoshii, Hiroshi; Yoshii, Yukie; Asai, Tatsuya; Furukawa, Takako; Takaichi, Shinichi; Fujibayashi, Yasuhisa

    2012-01-01

    Highlights: ► Some photo-excited carotenoids have photosensitizing ability. ► They are able to produce ROS. ► Photo-excited fucoxanthin can produce singlet oxygen through energy transfer. -- Abstract: Carotenoids, natural pigments widely distributed in algae and plants, have a conjugated double bond system. Their excitation energies are correlated with conjugation length. We hypothesized that carotenoids whose energy states are above the singlet excited state of oxygen (singlet oxygen) would possess photosensitizing properties. Here, we demonstrated that human skin melanoma (A375) cells are damaged through the photo-excitation of several carotenoids (neoxanthin, fucoxanthin and siphonaxanthin). In contrast, photo-excitation of carotenoids that possess energy states below that of singlet oxygen, such as β-carotene, lutein, loroxanthin and violaxanthin, did not enhance cell death. Production of reactive oxygen species (ROS) by photo-excited fucoxanthin or neoxanthin was confirmed using a reporter assay for ROS production with HeLa Hyper cells, which express a fluorescent indicator protein for intracellular ROS. Fucoxanthin and neoxanthin also showed high cellular penetration and retention. Electron spin resonance spectra using 2,2,6,6-tetramethil-4-piperidone as a singlet oxygen trapping agent demonstrated that singlet oxygen was produced via energy transfer from photo-excited fucoxanthin to oxygen molecules. These results suggest that carotenoids such as fucoxanthin, which are capable of singlet oxygen production through photo-excitation and show good penetration and retention in target cells, are useful as photosensitizers in photodynamic therapy for skin disease.

  1. Mitochondrial Signaling in Plants Under Hypoxia: Use of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS)

    DEFF Research Database (Denmark)

    Hebelstrup, Kim; Møller, Ian Max

    2015-01-01

    Hypoxia commonly occurs in roots in water-saturated soil and in maturing and germinating seeds. We here review the role of the mitochondria in the cellular response to hypoxia with an emphasis on the turnover of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) and their potential...

  2. Involvement of oxygen reactive species in the cellular response of carcinoma cells to irradiation

    International Nuclear Information System (INIS)

    Tulard, A.

    2004-06-01

    After a presentation of oxygen reactive species and their sources, the author describes the enzymatic and non-enzymatic anti-oxidative defenses, the physiological roles of oxygen reactive species, the oxidative stress, the water radiolysis, the anti-oxidative enzymes and the effects of ionizing radiations. The author then reports an investigation on the contribution of oxygen reactive species in the cellular response to irradiation, and an investigation on the influence of the breathing chain on the persistence of a radio-induced oxidative stress. He also reports a research on molecular mechanisms involved in the cellular radio-sensitivity

  3. Reactive oxygen species in the paraventricular nucleus of the hypothalamus alter sympathetic activity during metabolic syndrome.

    Directory of Open Access Journals (Sweden)

    JOSIANE CAMPOS CRUZ

    2015-12-01

    Full Text Available The paraventricular nucleus of the hypothalamus (PVN contains heterogeneous populations of neurons involved in autonomic and neuroendocrine regulation. The PVN plays an important role in the sympathoexcitatory response to increasing circulating levels of angiotensin II (Ang-II, which activates AT1 receptors in the circumventricular organs (OCVs, mainly in the subfornical organ (SFO. Circulating Ang-II induces a de novo synthesis of Ang-II in SFO neurons projecting to pre-autonomic PVN neurons. Activation of AT1 receptors induces intracellular increases in reactive oxygen species (ROS, leading to increases in sympathetic nerve activity (SNA. Chronic sympathetic nerve activation promotes a series of metabolic disorders that characterizes the metabolic syndrome (MetS: dyslipidemia, hyperinsulinemia, glucose intolerance, hyperleptinemia and elevated plasma hormone levels, such as noradrenaline, glucocorticoids, leptin, insulin and Ang-II. This review will discuss the contribution of our laboratory and others regarding the sympathoexcitation caused by peripheral Ang-II-induced reactive oxygen species along the subfornical organ and paraventricular nucleus of the hypothalamus. We hypothesize that this mechanism could be involved in metabolic disorders underlying MetS.

  4. Reactive oxygen species produced by irradiation of some phthalocyanine derivatives

    Czech Academy of Sciences Publication Activity Database

    Černý, J.; Karásková, M.; Rakušan, J.; Nešpůrek, Stanislav

    2010-01-01

    Roč. 210, č. 1 (2010), s. 82-88 ISSN 1010-6030 R&D Projects: GA AV ČR KAN400720701 Institutional research plan: CEZ:AV0Z40500505 Keywords : singlet oxygen * photosensitizer * phthalocyanine Subject RIV: CG - Electrochemistry Impact factor: 2.243, year: 2010

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

    DEFF Research Database (Denmark)

    Li, Hui; Jubelirer, Sara; Garcia Costas, Amaya M

    2009-01-01

    include cytochrome bd quinol oxidase, NADH oxidase, rubredoxin oxygen oxidoreductase, several thiol peroxidases, alkyl hydroperoxide reductase, superoxide dismutase, methionine sulfoxide reductase, and rubrerythrin. To test the physiological functions of some of these proteins, ten genes were...

  6. Effects of Reactive Oxygen Species on Tubular Transport along the Nephron.

    Science.gov (United States)

    Gonzalez-Vicente, Agustin; Garvin, Jeffrey L

    2017-03-23

    Reactive oxygen species (ROS) are oxygen-containing molecules naturally occurring in both inorganic and biological chemical systems. Due to their high reactivity and potentially damaging effects to biomolecules, cells express a battery of enzymes to rapidly metabolize them to innocuous intermediaries. Initially, ROS were considered by biologists as dangerous byproducts of respiration capable of causing oxidative stress, a condition in which overproduction of ROS leads to a reduction in protective molecules and enzymes and consequent damage to lipids, proteins, and DNA. In fact, ROS are used by immune systems to kill virus and bacteria, causing inflammation and local tissue damage. Today, we know that the functions of ROS are not so limited, and that they also act as signaling molecules mediating processes as diverse as gene expression, mechanosensation, and epithelial transport. In the kidney, ROS such as nitric oxide (NO), superoxide (O₂ - ), and their derivative molecules hydrogen peroxide (H₂O₂) and peroxynitrite (ONO₂ - ) regulate solute and water reabsorption, which is vital to maintain electrolyte homeostasis and extracellular fluid volume. This article reviews the effects of NO, O₂ - , ONO₂ - , and H₂O₂ on water and electrolyte reabsorption in proximal tubules, thick ascending limbs, and collecting ducts, and the effects of NO and O₂ - in the macula densa on tubuloglomerular feedback.

  7. Nitric Oxide and Reactive Oxygen Species in the Pathogenesis of Preeclampsia

    Directory of Open Access Journals (Sweden)

    Keiichi Matsubara

    2015-03-01

    Full Text Available Preeclampsia (PE is characterized by disturbed extravillous trophoblast migration toward uterine spiral arteries leading to increased uteroplacental vascular resistance and by vascular dysfunction resulting in reduced systemic vasodilatory properties. Its pathogenesis is mediated by an altered bioavailability of nitric oxide (NO and tissue damage caused by increased levels of reactive oxygen species (ROS. Furthermore, superoxide (O2− rapidly inactivates NO and forms peroxynitrite (ONOO−. It is known that ONOO− accumulates in the placental tissues and injures the placental function in PE. In addition, ROS could stimulate platelet adhesion and aggregation leading to intravascular coagulopathy. ROS-induced coagulopathy causes placental infarction and impairs the uteroplacental blood flow in PE. The disorders could lead to the reduction of oxygen and nutrients required for normal fetal development resulting in fetal growth restriction. On the other hand, several antioxidants scavenge ROS and protect tissues against oxidative damage. Placental antioxidants including catalase, superoxide dismutase (SOD, and glutathione peroxidase (GPx protect the vasculature from ROS and maintain the vascular function. However, placental ischemia in PE decreases the antioxidant activity resulting in further elevated oxidative stress, which leads to the appearance of the pathological conditions of PE including hypertension and proteinuria. Oxidative stress is defined as an imbalance between ROS and antioxidant activity. This review provides new insights about roles of oxidative stress in the pathophysiology of PE.

  8. Jellyfish blooms in China: Dominant species, causes and consequences

    International Nuclear Information System (INIS)

    Dong Zhijun; Liu Dongyan; Keesing, John K.

    2010-01-01

    Three jellyfish species, Aurelia aurita, Cyanea nozakii and Nemopilema nomurai, form large blooms in Chinese seas. We report on the distribution and increasing incidence of jellyfish blooms and their consequences in Chinese coastal seas and analyze their relationship to anthropogenically derived changes to the environment in order to determine the possible causes. A. aurita, C. nozakii and N. nomurai form blooms in the temperate Chinese seas including the northern East China Sea, Yellow Sea and Bohai Sea. N. nomurai forms offshore blooms while the other two species bloom mainly in inshore areas. Eutrophication, overfishing, habitat modification for aquaculture and climate change are all possible contributory factors facilitating plausible mechanisms for the proliferation of jellyfish blooms. In the absence of improvement in coastal marine ecosystem health, jellyfish blooms could be sustained and may even spread from the locations in which they now occur.

  9. Neonatal purpura fulminans caused by rare Citrobacter species

    Directory of Open Access Journals (Sweden)

    Sanjiv Vijay Choudhary

    2018-01-01

    Full Text Available A 23-day-old neonate, born of nonconsangious marriage, admitted to Neonatal Intensive Care Unit for hypernatremic dehydration with petechiae and ecchymotic patches and necrotic skin lesions for 10–12 days was referred to dermatology department. On the general examination, pulse was 158/min, and respiratory rate was 52/min, and systemic examination was normal. Hematological investigations showed pancytopenia. Bleeding time was normal but prothrombin time and activated partial thromboplastin time reports were prolonged. D-dimer levels were elevated. Urine and stool were normal. Blood culture and sensitivity report revealed the growth of Citrobacter species with sensitivity to ciprofloxacin, amikacin, tetracycline, and resistance to Imipenem. Histopathology revealed epidermal hyperkeratosis with epidermal-dermal splitting, vessels showing fibrin occlusion with red blood cell extravasation into the perivascular areas in dermis along with dermal necrosis. To the best of our knowledge, this might be the first case of purpura fulminans in a neonate caused by rare Citrobacter species.

  10. Oxygen-containing coke species in zeolite-catalyzed conversion of methanol to hydrocarbons

    KAUST Repository

    Liu, Zhaohui; Dong, Xinglong; Liu, Xin; Han, Yu

    2016-01-01

    Zeolites are the most commonly used catalysts for methanol-to-hydrocarbon (MTH) conversion. Here, we identified two oxygen-containing compounds as coke species in zeolite catalysts after MTH reactions. We investigated the possible influences

  11. Oxygen isotopic analyses of individual planktic foraminifera species: Implications for seasonality in the western Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Niitsuma, N.; Naik, S.S.

    The variation of stable isotopes between individual shells of planktic foraminifera of a given species and size may provide short-term seasonal insight on Paleoceanography. In this context, oxygen isotope analyses of individual Globigerinoides...

  12. Prodrugs activated by reactive oxygen species for use in the treatment of inflammatory diseases and cancer

    DEFF Research Database (Denmark)

    2018-01-01

    Prodrugs activated predominantly or exclusively in inflammatory tissue, more particularly prodrugs of methotrexate and derivatives thereof, which are selectively activated by Reactive Oxygen Species (ROS) in inflammatory tissues associated with cancer and inflammatory diseases, as well as method...

  13. Mitochondrion-derived reactive oxygen species lead to enhanced amyloid beta formation

    NARCIS (Netherlands)

    Leuner, K.; Schutt, T.; Kurz, C.; Eckert, S.H.; Schiller, C.; Occhipinti, A.; Mai, S.; Jendrach, M.; Eckert, G.P.; Kruse, S.E.; Palmiter, R.D.; Brandt, U.; Drose, S.; Wittig, I.; Willem, M.; Haass, C.; Reichert, A.S.; Muller, W.E.

    2012-01-01

    AIMS: Intracellular amyloid beta (Abeta) oligomers and extracellular Abeta plaques are key players in the progression of sporadic Alzheimer's disease (AD). Still, the molecular signals triggering Abeta production are largely unclear. We asked whether mitochondrion-derived reactive oxygen species

  14. Solar light-induced production of reactive oxygen species by single walled carbon nanotubes in water

    Science.gov (United States)

    Photosensitizing processes of engineered nanomaterials (ENMs) which include photo-induced production of reactive oxygen species (ROS) convert light energy into oxidizing chemical energy that mediates transformations of nanomaterials. The oxidative stress associated with ROS may p...

  15. DMPD: NF-kappaB activation by reactive oxygen species: fifteen years later. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16723122 NF-kappaB activation by reactive oxygen species: fifteen years later. Gloi...svg) (.html) (.csml) Show NF-kappaB activation by reactive oxygen species: fifteen years later. PubmedID 167...23122 Title NF-kappaB activation by reactive oxygen species: fifteen years later.

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

    Directory of Open Access Journals (Sweden)

    Okada Futoshi

    2005-09-01

    Full Text Available Abstract 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.

  17. Restraining reactive oxygen species in Listeria monocytogenes promotes the apoptosis of glial cells.

    Science.gov (United States)

    Li, Sen; Li, Yixuan; Chen, Guowei; Zhang, Jingchen; Xu, Fei; Wu, Man

    2017-07-01

    Listeria monocytogenes is a facultative anaerobic foodborne pathogen that can traverse the blood-brain barrier and cause brain infection. L. monocytogenes infection induces host cell apoptosis in several cell types. In this study, we investigated the apoptosis of human glioma cell line U251 invaded by L. monocytogenes and evaluated the function of bacterial reactive oxygen species (ROS) during infection. Bacterial ROS level was reduced by carrying out treatment with N-acetyl cysteine (NAC) and diphenyleneiodonium chloride (DPI). After infection, the apoptosis of U251 cells was examined by flow cytometry assay and propidium iodide staining. DPI and NAC efficiently decreased ROS level in L. monocytogenes without affecting bacterial growth. Moreover, the apoptosis of glial cells was enhanced upon invasion of DPI- and NAC-pretreated L. monocytogenes. Results indicate that the apoptosis of glial cells can be induced by L. monocytogenes, and that the inhibition of bacterial ROS increases the apoptosis of host cells.

  18. Reactive species formed on proteins exposed to singlet oxygen

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan

    2004-01-01

    Singlet oxygen ((1)O(2)) is believed to be generated in biological systems by a range of endogenous processes (e.g. enzymatic and chemical reactions) and exogenous stimuli (e.g. UV or visible light in the presence of a sensitiser). Kinetic data is consistent with proteins being a major target...... hydroperoxides, which can be reduced to the corresponding alcohols; other products arising from radical intermediates can also be generated, particularly in the presence of UV light and metal ions. With His side-chains, poorly characterised peroxides are also formed. Reaction with Met and Cys has been proposed...

  19. Marine species in ambient low-oxygen regions subject to double jeopardy impacts of climate change.

    Science.gov (United States)

    Stortini, Christine H; Chabot, Denis; Shackell, Nancy L

    2017-06-01

    We have learned much about the impacts of warming on the productivity and distribution of marine organisms, but less about the impact of warming combined with other environmental stressors, including oxygen depletion. Also, the combined impact of multiple environmental stressors requires evaluation at the scales most relevant to resource managers. We use the Gulf of St. Lawrence, Canada, characterized by a large permanently hypoxic zone, as a case study. Species distribution models were used to predict the impact of multiple scenarios of warming and oxygen depletion on the local density of three commercially and ecologically important species. Substantial changes are projected within 20-40 years. A eurythermal depleted species already limited to shallow, oxygen-rich refuge habitat (Atlantic cod) may be relatively uninfluenced by oxygen depletion but increase in density within refuge areas with warming. A more stenothermal, deep-dwelling species (Greenland halibut) is projected to lose ~55% of its high-density areas under the combined impacts of warming and oxygen depletion. Another deep-dwelling, more eurythermal species (Northern shrimp) would lose ~4% of its high-density areas due to oxygen depletion alone, but these impacts may be buffered by warming, which may increase density by 8% in less hypoxic areas, but decrease density by ~20% in the warmest parts of the region. Due to local climate variability and extreme events, and that our models cannot project changes in species sensitivity to hypoxia with warming, our results should be considered conservative. We present an approach to effectively evaluate the individual and cumulative impacts of multiple environmental stressors on a species-by-species basis at the scales most relevant to managers. Our study may provide a basis for work in other low-oxygen regions and should contribute to a growing literature base in climate science, which will continue to be of support for resource managers as climate change

  20. Phototoxicity Evaluation of Pharmaceutical Substances with a Reactive Oxygen Species Assay Using Ultraviolet A

    Science.gov (United States)

    Lee, Yong Sun; Yi, Jung-Sun; Lim, Hye Rim; Kim, Tae Sung; Ahn, Il Young; Ko, Kyungyuk; Kim, JooHwan; Park, Hye-Kyung; Sohn, Soo Jung; Lee, Jong Kwon

    2017-01-01

    With ultraviolet and visible light exposure, some pharmaceutical substances applied systemically or topically may cause phototoxic skin irritation. The major factor in phototoxicity is the generation of reactive oxygen species (ROS) such as singlet oxygen and superoxide anion that cause oxidative damage to DNA, lipids and proteins. Thus, measuring the generation of ROS can predict the phototoxic potential of a given substance indirectly. For this reason, a standard ROS assay (ROS assay) was developed and validated and provides an alternative method for phototoxicity evaluation. However, negative substances are over-predicted by the assay. Except for ultraviolet A (UVA), other UV ranges are not a major factor in causing phototoxicity and may lead to incorrect labeling of some non-phototoxic substances as being phototoxic in the ROS assay when using a solar simulator. A UVA stimulator is also widely used to evaluate phototoxicity in various test substances. Consequently, we identified the applicability of a UVA simulator to the ROS assay for photoreactivity. In this study, we tested 60 pharmaceutical substances including 50 phototoxins and 10 non-phototoxins to predict their phototoxic potential via the ROS assay with a UVA simulator. Following the ROS protocol, all test substances were dissolved in dimethyl sulfoxide or sodium phosphate buffer. The final concentration of the test solutions in the reaction mixture was 20 to 200 μM. The exposure was with 2.0~2.2 mW/cm2 irradiance and optimization for a relevant dose of UVA was performed. The generation of ROS was compared before and after UVA exposure and was measured by a microplate spectrophotometer. Sensitivity and specificity values were 85.7% and 100.0% respectively, and the accuracy was 88.1%. From this analysis, the ROS assay with a UVA simulator is suitable for testing the photoreactivity and estimating the phototoxic potential of various test pharmaceutical substances. PMID:28133512

  1. Direct observation of the dealloying process of a platinum–yttrium nanoparticle fuel cell cathode and its oxygenated species during the oxygen reduction reaction

    DEFF Research Database (Denmark)

    Malacrida, Paolo; Sanchez Casalongue, Hernan G.; Masini, Federico

    2015-01-01

    . It proceeds through the progressive oxidation of alloyed Y atoms, soon leading to the accumulation of Y3+ cations at the cathode. Acid leaching with sulfuric acid is capable of accelerating the dealloying process and removing these Y3+ cations which might cause long term degradation of the membrane. The use...... of APXPS under near operating conditions allowed observing the population of oxygenated surface species as a function of the electrochemical potential. Similar to the case of pure Pt nanoparticles, non-hydrated hydroxide plays a key role in the ORR catalytic process....

  2. Involvement of reactive oxygen species (ROS) in the induction of genetic instability by radiation

    International Nuclear Information System (INIS)

    Tominaga, Hideyuki; Kodama, Seiji; Suzuki, Keiji; Watanabe, Masami; Matsuda, Naoki

    2004-01-01

    Radiation generates reactive oxygen species (ROS) that interact with cellular molecules, including DNA, lipids, and proteins. To know how ROS contribute to the induction of genetic instability, we examined the effect of the anti-ROS condition, using both ascorbic acid phosphate (APM) treatment or a low oxygen condition, on the induction of delayed reproductive cell death and delayed chromosome aberrations. The primary surviving colonies of mouse m5S-derived cl. 2011-14 cells irradiated with 6 Gy of X-rays were replated and allowed to form secondary colonies. The anti-ROS treatments were applied to either preirradiation culture or postirradiation cultures for primary or secondary colony formation. Both anti-ROS conditions relieved X-ray-induced acute cell killing to a similar extent. These anti-ROS conditions also relieved genetic instability when those conditions were applied during primary colony formation. However, no effect was observed when the conditions were applied during preirradiation culture and secondary colony formation. We also demonstrated that the amounts of ROS in X-ray-irradiated cells rapidly increase and then decrease at 6 hr postirradiation, and the levels of ROS then gradually decrease to a baseline within 2 weeks. The APM treatment kept the ROS production at a lower level than an untreated control. These results suggest that the cause of genetic instability might be fixed by ROS during a 2-week postirradiation period. (author)

  3. High salt-induced excess reactive oxygen species production resulted in heart tube malformation during gastrulation.

    Science.gov (United States)

    Gao, Lin-Rui; Wang, Guang; Zhang, Jing; Li, Shuai; Chuai, Manli; Bao, Yongping; Hocher, Berthold; Yang, Xuesong

    2018-09-01

    An association has been proved between high salt consumption and cardiovascular mortality. In vertebrates, the heart is the first functional organ to be formed. However, it is not clear whether high-salt exposure has an adverse impact on cardiogenesis. Here we report high-salt exposure inhibited basement membrane breakdown by affecting RhoA, thus disturbing the expression of Slug/E-cadherin/N-cadherin/Laminin and interfering with mesoderm formation during the epithelial-mesenchymal transition(EMT). Furthermore, the DiI + cell migration trajectory in vivo and scratch wound assays in vitro indicated that high-salt exposure restricted cell migration of cardiac progenitors, which was caused by the weaker cytoskeleton structure and unaltered corresponding adhesion junctions at HH7. Besides, down-regulation of GATA4/5/6, Nkx2.5, TBX5, and Mef2c and up-regulation of Wnt3a/β-catenin caused aberrant cardiomyocyte differentiation at HH7 and HH10. High-salt exposure also inhibited cell proliferation and promoted apoptosis. Most importantly, our study revealed that excessive reactive oxygen species(ROS)generated by high salt disturbed the expression of cardiac-related genes, detrimentally affecting the above process including EMT, cell migration, differentiation, cell proliferation and apoptosis, which is the major cause of malformation of heart tubes. © 2018 Wiley Periodicals, Inc.

  4. Detection of reactive oxygen species in isolated, perfused lungs by electron spin resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    Schudt Christian

    2005-07-01

    Full Text Available Abstract Background The sources and measurement of reactive oxygen species (ROS in intact organs are largely unresolved. This may be related to methodological problems associated with the techniques currently employed for ROS detection. Electron spin resonance (ESR with spin trapping is a specific method for ROS detection, and may address some these technical problems. Methods We have established a protocol for the measurement of intravascular ROS release from isolated buffer-perfused and ventilated rabbit and mouse lungs, combining lung perfusion with the spin probe l-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CPH and ESR spectroscopy. We then employed this technique to characterize hypoxia-dependent ROS release, with specific attention paid to NADPH oxidase-dependent superoxide formation as a possible vasoconstrictor pathway. Results While perfusing lungs with CPH over a range of inspired oxygen concentrations (1–21 %, the rate of CP• formation exhibited an oxygen-dependence, with a minimum at 2.5 % O2. Addition of superoxide dismutase (SOD to the buffer fluid illustrated that a minor proportion of this intravascular ROS leak was attributable to superoxide. Stimulation of the lungs by injection of phorbol-12-myristate-13-acetate (PMA into the pulmonary artery caused a rapid increase in CP• formation, concomitant with pulmonary vasoconstriction. Both the PMA-induced CPH oxidation and the vasoconstrictor response were largely suppressed by SOD. When the PMA challenge was performed at different oxygen concentrations, maximum superoxide liberation and pulmonary vasoconstriction occurred at 5 % O2. Using a NADPH oxidase inhibitor and NADPH-oxidase deficient mice, we illustrated that the PMA-induced superoxide release was attributable to the stimulation of NADPH oxidases. Conclusion The perfusion of isolated lungs with CPH is suitable for detection of intravascular ROS release by ESR spectroscopy. We employed this technique to

  5. Reactive Oxygen Species on the Early Earth and Survival of Bacteria

    Science.gov (United States)

    Balk, Melikea; Mason, Paul; Stams, Alfons J. M.; Smidt, Hauke; Freund, Friedemann; Rothschild, Lynn

    2011-01-01

    An oxygen-rich atmosphere appears to have been a prerequisite for complex, multicellular life to evolve on Earth and possibly elsewhere in the Universe. However it remains unclear how free oxygen first became available on the early Earth. A potentially important, and as yet poorly constrained pathway, is the production of oxygen through the weathering of rocks and release into the near-surface environment. Reactive Oxygen Species (ROS), as precursors to molecular oxygen, are a key step in this process, and may have had a decisive impact on the evolution of life, present and past. ROS are generated from minerals in igneous rocks during hydrolysis of peroxy defects, which consist of pairs of oxygen anions oxidized to the valence state -1 and during (bio) transformations of iron sulphide minerals. ROS are produced and consumed by intracellular and extracellular reactions of Fe, Mn, C, N, and S species. We propose that, despite an overall reducing or neutral oxidation state of the macroenvironment and the absence of free O2 in the atmosphere, organisms on the early Earth had to cope with ROS in their microenvironments. They were thus under evolutionary pressure to develop enzymatic and other defences against the potentially dangerous, even lethal effects of oxygen and its derived ROS. Conversely it appears that microorganisms learned to take advantage of the enormous reactive potential and energy gain provided by nascent oxygen. We investigate how oxygen might be released through weathering. We test microorganisms in contact with rock surfaces and iron sulphides. We model bacteria such as Deionococcus radiodurans and Desulfotomaculum, Moorella and Bacillus species for their ability to grow or survive in the presence of ROS. We examine how early Life might have adapted to oxygen.

  6. Using Paraquat to Generate Anion Free Radicals and Hydrogen Peroxide in "In Vitro": Antioxidant Effect of Vitamin E--A Procedure to Teach Theoretical and Experimental Principles of Reactive Oxygen Species Biochemistry

    Science.gov (United States)

    Jimenez-Del-Rio, Marlene; Suarez-Cedeno, Gerson; Velez-Pardo, Carlos

    2010-01-01

    The theoretical basis of reactive oxygen species and their impact on health issues are relatively easy to understand by biomedical students. The detection of reactive oxygen species requires expensive equipment, the procedures are time consuming and costly, and the results are hard to interpret. Moreover, cause-and-effect relationships in the…

  7. Radiation induces aerobic glycolysis through reactive oxygen species

    International Nuclear Information System (INIS)

    Zhong, Jim; Rajaram, Narasimhan; Brizel, David M.; Frees, Amy E.; Ramanujam, Nirmala; Batinic-Haberle, Ines; Dewhirst, Mark W.

    2013-01-01

    Background and purpose: Although radiation induced reoxygenation has been thought to increase radiosensitivity, we have shown that its associated oxidative stress can have radioprotective effects, including stabilization of the transcription factor hypoxia inducible factor 1 (HIF-1). HIF-1 is known to regulate many of the glycolytic enzymes, thereby promoting aerobic glycolysis, which is known to promote treatment resistance. Thus, we hypothesized that reoxygenation after radiation would increase glycolysis. We previously showed that blockade of oxidative stress using a superoxide dismutase (SOD) mimic during reoxygenation can downregulate HIF-1 activity. Here we tested whether concurrent use of this drug with radiotherapy would reduce the switch to a glycolytic phenotype. Materials and methods: 40 mice with skin fold window chambers implanted with 4T1 mammary carcinomas were randomized into (1) no treatment, (2) radiation alone, (3) SOD mimic alone, and (4) SOD mimic with concurrent radiation. All mice were imaged on the ninth day following tumor implantation (30 h following radiation treatment) following injection of a fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG). Hemoglobin saturation was measured by using hyperspectral imaging to quantify oxygenation state. Results: Mice treated with radiation showed significantly higher 2-NBDG fluorescence compared to controls (p = 0.007). Hemoglobin saturation analysis demonstrated reoxygenation following radiation, coinciding with the observed increase in glycolysis. The concurrent use of the SOD mimic with radiation demonstrated a significant reduction in 2-NBDG fluorescence compared to effects seen after radiation alone, while having no effect on reoxygenation. Conclusions: Radiation induces an increase in tumor glucose demand approximately 30 h following therapy during reoxygenation. The use of an SOD mimic can prevent the increase in aerobic glycolysis when used

  8. Comparative analyses of Legionella species identifies genetic features of strains causing Legionnaires' disease.

    Science.gov (United States)

    Gomez-Valero, Laura; Rusniok, Christophe; Rolando, Monica; Neou, Mario; Dervins-Ravault, Delphine; Demirtas, Jasmin; Rouy, Zoe; Moore, Robert J; Chen, Honglei; Petty, Nicola K; Jarraud, Sophie; Etienne, Jerome; Steinert, Michael; Heuner, Klaus; Gribaldo, Simonetta; Médigue, Claudine; Glöckner, Gernot; Hartland, Elizabeth L; Buchrieser, Carmen

    2014-01-01

    The genus Legionella comprises over 60 species. However, L. pneumophila and L. longbeachae alone cause over 95% of Legionnaires’ disease. To identify the genetic bases underlying the different capacities to cause disease we sequenced and compared the genomes of L. micdadei, L. hackeliae and L. fallonii (LLAP10), which are all rarely isolated from humans. We show that these Legionella species possess different virulence capacities in amoeba and macrophages, correlating with their occurrence in humans. Our comparative analysis of 11 Legionella genomes belonging to five species reveals highly heterogeneous genome content with over 60% representing species-specific genes; these comprise a complete prophage in L. micdadei, the first ever identified in a Legionella genome. Mobile elements are abundant in Legionella genomes; many encode type IV secretion systems for conjugative transfer, pointing to their importance for adaptation of the genus. The Dot/Icm secretion system is conserved, although the core set of substrates is small, as only 24 out of over 300 described Dot/Icm effector genes are present in all Legionella species. We also identified new eukaryotic motifs including thaumatin, synaptobrevin or clathrin/coatomer adaptine like domains. Legionella genomes are highly dynamic due to a large mobilome mainly comprising type IV secretion systems, while a minority of core substrates is shared among the diverse species. Eukaryotic like proteins and motifs remain a hallmark of the genus Legionella. Key factors such as proteins involved in oxygen binding, iron storage, host membrane transport and certain Dot/Icm substrates are specific features of disease-related strains.

  9. Moscatilin Inhibits Lung Cancer Cell Motility and Invasion via Suppression of Endogenous Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Akkarawut Kowitdamrong

    2013-01-01

    Full Text Available Lung cancer is the leading cause of death among cancer patients worldwide, and most of them have died from metastasis. Migration and invasion are prerequisite processes associated with high metastasis potential in cancers. Moscatilin, a bibenzyl derivative isolated from the Thai orchid Dendrobium pulchellum, has been shown to have anticancer effect against numerous cancer cell lines. However, little is known regarding the effect of moscatilin on cancer cell migration and invasion. The present study demonstrates that nontoxic concentrations of moscatilin were able to inhibit human nonsmall cell lung cancer H23 cell migration and invasion. The inhibitory effect of moscatilin was associated with an attenuation of endogenous reactive oxygen species (ROS, in which hydroxyl radical (OH∙ was identified as a dominant species in the suppression of filopodia formation. Western blot analysis also revealed that moscatilin downregulated activated focal adhesion kinase (phosphorylated FAK, Tyr 397 and activated ATP-dependent tyrosine kinase (phosphorylated Akt, Ser 473, whereas their parental counterparts were not detectable changed. In conclusion, our results indicate the novel molecular basis of moscalitin-inhibiting lung cancer cell motility and invasion and demonstrate a promising antimetastatic potential of such an agent for lung cancer therapy.

  10. Generation of reactive oxygen species from porous silicon microparticles in cell culture medium.

    Science.gov (United States)

    Low, Suet Peng; Williams, Keryn A; Canham, Leigh T; Voelcker, Nicolas H

    2010-06-01

    Nanostructured (porous) silicon is a promising biodegradable biomaterial, which is being intensively researched as a tissue engineering scaffold and drug-delivery vehicle. Here, we tested the biocompatibility of non-treated and thermally-oxidized porous silicon particles using an indirect cell viability assay. Initial direct cell culture on porous silicon determined that human lens epithelial cells only poorly adhered to non-treated porous silicon. Using an indirect cell culture assay, we found that non-treated microparticles caused complete cell death, indicating that these particles generated a toxic product in cell culture medium. In contrast, thermally-oxidized microparticles did not reduce cell viability significantly. We found evidence for the generation of reactive oxygen species (ROS) by means of the fluorescent probe 2',7'-dichlorofluorescin. Our results suggest that non-treated porous silicon microparticles produced ROS, which interacted with the components of the cell culture medium, leading to the formation of cytotoxic species. Oxidation of porous silicon microparticles not only mitigated, but also abolished the toxic effects.

  11. Interconnection of reactive oxygen species chemistry across the interfaces of atmospheric, environmental, and biological processes.

    Science.gov (United States)

    Anglada, Josep M; Martins-Costa, Marilia; Francisco, Joseph S; Ruiz-López, Manuel F

    2015-03-17

    Oxidation reactions are ubiquitous and play key roles in the chemistry of the atmosphere, in water treatment processes, and in aerobic organisms. Ozone (O3), hydrogen peroxide (H2O2), hydrogen polyoxides (H2Ox, x > 2), associated hydroxyl and hydroperoxyl radicals (HOx = OH and HO2), and superoxide and ozonide anions (O2(-) and O3(-), respectively) are the primary oxidants in these systems. They are commonly classified as reactive oxygen species (ROS). Atmospheric chemistry is driven by a complex system of chain reactions of species, including nitrogen oxides, hydroxyl and hydroperoxide radicals, alkoxy and peroxy radicals, and ozone. HOx radicals contribute to keeping air clean, but in polluted areas, the ozone concentration increases and creates a negative impact on plants and animals. Indeed, ozone concentration is used to assess air quality worldwide. Clouds have a direct effect on the chemical composition of the atmosphere. On one hand, cloud droplets absorb many trace atmospheric gases, which can be scavenged by rain and fog. On the other hand, ionic species can form in this medium, which makes the chemistry of the atmosphere richer and more complex. Furthermore, recent studies have suggested that air-cloud interfaces might have a significant impact on the overall chemistry of the troposphere. Despite the large differences in molecular composition, concentration, and thermodynamic conditions among atmospheric, environmental, and biological systems, the underlying chemistry involving ROS has many similarities. In this Account, we examine ROS and discuss the chemical characteristics common to all of these systems. In water treatment, ROS are key components of an important subset of advanced oxidation processes. Ozonation, peroxone chemistry, and Fenton reactions play important roles in generating sufficient amounts of hydroxyl radicals to purify wastewater. Biochemical processes within living organisms also involve ROS. These species can come from pollutants in

  12. Combined effect of protein and oxygen on reactive oxygen and nitrogen species in the plasma treatment of tissue

    Science.gov (United States)

    Gaur, Nishtha; Szili, Endre J.; Oh, Jun-Seok; Hong, Sung-Ha; Michelmore, Andrew; Graves, David B.; Hatta, Akimitsu; Short, Robert D.

    2015-09-01

    The influence of protein and molecular, ground state oxygen (O2) on the plasma generation, and transport of reactive oxygen and nitrogen species (RONS) in tissue are investigated. A tissue target, comprising a 1 mm thick gelatin film (a surrogate for real tissue), is placed on top of a 96-well plate; each well is filled with phosphate buffered saline (PBS, pH 7.4) containing one fluorescent or colorimetric reporter that is specific for one of three RONS (i.e., H2O2, NO2-, or OH•) or a broad spectrum reactive oxygen species reporter (2,7-dichlorodihydrofluorescein). A helium cold atmospheric plasma (CAP) jet contacts the top of the gelatin surface, and the concentrations of RONS generated in PBS are measured on a microplate reader. The data show that H2O2, NO2-, or OH• are generated in PBS underneath the target. Independently, measurements are made of the O2 concentration in the PBS with and without the gelatin target. Adding bovine serum albumin protein to the PBS or gelatin shows that protein either raises or inhibits RONS depending upon the O2 concentration. Our results are discussed in the context of plasma-soft tissue interactions that are important in the development of CAP technology for medicine, biology, and food manufacturing.

  13. Nitric oxide and reactive oxygen species in limb vascular function

    DEFF Research Database (Denmark)

    Gliemann, Lasse; Nyberg, Michael Permin; Hellsten, Ylva

    2014-01-01

    and xanthine oxidase and the degree of ROS removal through the antioxidant defense system. The development of cardiovascular disease has been proposed to be closely related to a reduced bioavailability of NO in parallel with an increased presence of ROS. Excessive levels of ROS not only lower...... the bioavailability of NO but may also cause cellular damage in the cardiovascular system. Physical activity has been shown to greatly improve cardiovascular function, in part through improved bioavailability of NO, enhanced endogenous antioxidant defense and a lowering of the expression of ROS forming enzymes...

  14. Prevalence & susceptibility to fluconazole of Candida species causing vulvovaginitis.

    Science.gov (United States)

    Mohanty, Srujana; Xess, Immaculata; Hasan, Fahmi; Kapil, Arti; Mittal, Suneeta; Tolosa, Jorge E

    2007-09-01

    Vulvovaginal candidiasis is an important cause of morbidity in women of reproductive age. This study was carried out to determine the species prevalence and susceptibility pattern to fluconazole of yeasts isolated from the vagina of symptomatic women. This prospective study was conducted in a rural primary health care center of north India from May 2003 to April 2004 and included 601 married, sexually active women (18-49 yr) with the self reported symptoms of vaginal discharge and/or genital itching and/or genital burning. Specific aetiology of the genitourinary symptoms including candidal infection were determined. Specimens from the lateral wall of vagina were subjected to direct wet mount microscopy and fungal culture on Sabouraud's dextrose agar. Susceptibility testing to fluconazole was carried out using broth microdilution method. Yeasts were isolated in 111 (18.5%) women and these consisted of Candida glabrata (56, 50.4%), C. albicans (39, 35.1%), C. tropicalis (12, 10.8%), C. krusei (3, 2.7%) and C. parapsilosis (1, 0.9%). Susceptibility testing carried out on 30 representative isolates (15 C. glabrata, 10 C. albicans, 4 C. tropicalis and 1 C. parapsilosis) revealed that 21 isolates (70%) were susceptible (MIC, < or = 8 microg/ml) to fluconazole while 9 (30%) were susceptible-dose dependent (S-DD, MIC 16-32 microg/ml). Our findings suggest a low prevalence of fluconazole resistance in vaginal candida isolates in our population. However, a high prevalence of non-albicans candida species and increased dose-dependent resistance in these isolates necessitates vigilance since this may warrant a change in the optimal therapy of non-albicans candida vaginitis.

  15. Manipulation of environmental oxygen modifies reactive oxygen and nitrogen species generation during myogenesis

    Directory of Open Access Journals (Sweden)

    Rachel McCormick

    2016-08-01

    Data demonstrate that satellite cell proliferation increased when cells were grown in 6% O2 compared with 20% O2. Myoblasts grown in 20% O2 showed an increase in DCF fluorescence and DHE oxidation compared with myoblasts grown at 6% O2. Myotubes grown in 20% O2 also showed an increase in DCF and DAF-FM fluorescence and DHE oxidation compared with myotubes grown in 6% O2. The catalase and MnSOD contents were also increased in myoblasts and myotubes that were maintained in 20% O2 compared with myoblasts and myotubes grown in 6% O2. These data indicate that intracellular RONS activities in myoblasts and myotubes at rest are influenced by changes in environmental oxygen concentration and that the increased ROS may influence myogenesis in a negative manner.

  16. The Role of Reactive Oxygen Species and Autophagy in Periodontitis and Their Potential Linkage

    Directory of Open Access Journals (Sweden)

    Chengcheng Liu

    2017-06-01

    Full Text Available Periodontitis is a chronic inflammatory disease that causes damage to periodontal tissues, which include the gingiva, periodontal ligament, and alveolar bone. The major cause of periodontal tissue destruction is an inappropriate host response to microorganisms and their products. Specifically, a homeostatic imbalance between reactive oxygen species (ROS and antioxidant defense systems has been implicated in the pathogenesis of periodontitis. Elevated levels of ROS acting as intracellular signal transducers result in autophagy, which plays a dual role in periodontitis by promoting cell death or blocking apoptosis in infected cells. Autophagy can also regulate ROS generation and scavenging. Investigations are ongoing to elucidate the crosstalk mechanisms between ROS and autophagy. Here, we review the physiological and pathological roles of ROS and autophagy in periodontal tissues. The redox-sensitive pathways related to autophagy, such as mTORC1, Beclin 1, and the Atg12-Atg5 complex, are explored in depth to provide a comprehensive overview of the crosstalk between ROS and autophagy. Based on the current evidence, we suggest that a potential linkage between ROS and autophagy is involved in the pathogenesis of periodontitis.

  17. Super-oxidation of silicon nanoclusters: magnetism and reactive oxygen species at the surface

    Energy Technology Data Exchange (ETDEWEB)

    Lepeshkin, Sergey; Baturin, Vladimir; Tikhonov, Evgeny; Matsko, Nikita; Uspenskii, Yurii; Naumova, Anastasia; Feya, Oleg; Schoonen, Martin A.; Oganov, Artem R.

    2016-01-01

    Oxidation of silicon nanoclusters depending on the temperature and oxygen pressure is explored from first principles using the evolutionary algorithm, and structural and thermodynamic analysis. From our calculations of 90 SinOm clusters we found that under normal conditions oxidation does not stop at the stoichiometric SiO2 composition, as it does in bulk silicon, but goes further placing extra oxygen atoms on the cluster surface. These extra atoms are responsible for light emission, relevant to reactive oxygen species and many of them are magnetic. We argue that the super-oxidation effect is size-independent and discuss its relevance to nanotechnology and miscellaneous applications, including biomedical ones.

  18. Measuring reactive oxygen and nitrogen species with fluorescent probes: challenges and limitations

    Science.gov (United States)

    Kalyanaraman, Balaraman; Darley-Usmar, Victor; Davies, Kelvin J.A.; Dennery, Phyllis A.; Forman, Henry Jay; Grisham, Matthew B.; Mann, Giovanni E.; Moore, Kevin; Roberts, L. Jackson; Ischiropoulos, Harry

    2013-01-01

    The purpose of this position paper is to present a critical analysis of the challenges and limitations of the most widely used fluorescent probes for detecting and measuring reactive oxygen and nitrogen species. Where feasible, we have made recommendations for the use of alternate probes and appropriate analytical techniques that measure the specific products formed from the reactions between fluorescent probes and reactive oxygen and nitrogen species. We have proposed guidelines that will help present and future researchers with regard to the optimal use of selected fluorescent probes and interpretation of results. PMID:22027063

  19. Assessing the impacts of deoxygenation on marine species using blood-oxygen binding thresholds as proxies for hypoxia tolerance in the water column

    Science.gov (United States)

    Smith-Mislan, A.; Deutsch, C.; Dunne, J. P.; Sarmiento, J. L.

    2016-02-01

    Oxygen and temperature decrease, often rapidly, from shallow to deeper depths, restricting the ability of marine species to use the vertical habitat. One physiological trait that determines the tolerance of organisms to low oxygen is the oxygen affinity of respiratory pigments, hemoglobin and hemocyanin, in the blood. Oxygen affinity is sensitive to temperature because the reversible reaction between oxygen and blood pigments absorbs or releases energy, called the heat of oxygenation. To quantify the range of oxygen affinities for marine species, we surveyed the literature for measurements of oxygen binding to blood at multiple temperatures. Oxygen affinity is mapped within the ocean environment using the depth at which oxygen pressure decreases to the point at which the blood is 50% oxygenated (P50 depth) as organisms move from the surface to depth in the ocean water column. We calculate P50 depths for hydrographic observations and model simulations and find that vertical gradients in both temperature and oxygen impact the vertical position and areal extent of P50 depths. Shifts in P50 due to temperature cause physiological types with the same P50 in the surface ocean to have different P50 depths and physiological types with different P50's in the surface ocean to have the same P50 depth. The vertical distances between P50 depths are spatially variable, which may determine the frequency of ecological interactions, such as competition and predation. P50 depths provide new insights into the historical and future impacts of changing hypoxic zones on species living in pelagic habitats.

  20. Pretreatment of Parsley (Petroselinum crispum L.) Suspension Cultures with Methyl Jasmonate Enhances Elicitation of Activated Oxygen Species.

    Science.gov (United States)

    Kauss, H.; Jeblick, W.; Ziegler, J.; Krabler, W.

    1994-01-01

    Suspension-cultured cells of parsley (Petroselinum crispum L.) were used to demonstrate an influence of jasmonic acid methyl ester (JAME) on the elicitation of activated oxygen species. Preincubation of the cell cultures for 1 d with JAME greatly enhanced the subsequent induction by an elicitor preparation from cell walls of Phytophtora megasperma f. sp. glycinea (Pmg elicitor) and by the polycation chitosan. Shorter preincubation times with JAME were less efficient, and the effect was saturated at about 5 [mu]M JAME. Treatment of the crude Pmg elicitor with trypsin abolished induction of activated oxygen species, an effect similar to that seen with elicitation of coumarin secretion. These results suggest that JAME conditioned the parsley suspension cells in a time-dependent manner to become more responsive to elicitation, reminiscent of developmental effects caused by JAME in whole plants. It is interesting that pretreatment of the parsley cultures with 2,6-dichloroisonicotinic and 5-chlorosalicylic acid only slightly enhanced the elicitation of activated oxygen species, whereas these substances greatly enhanced the elicitation of coumarin secretion. Therefore, these presumed inducers of systemic acquired resistance exhibit a specificity different from JAME. PMID:12232189

  1. Enhanced reactive oxygen species overexpression by CuO nanoparticles in poorly differentiated hepatocellular carcinoma cells

    Science.gov (United States)

    Kung, Mei-Lang; Hsieh, Shu-Ling; Wu, Chih-Chung; Chu, Tian-Huei; Lin, Yu-Chun; Yeh, Bi-Wen; Hsieh, Shuchen

    2015-01-01

    Copper oxide nanoparticles (CuO NPs) are known to exhibit toxic effects on a variety of cell types and organs. To determine the oxidative impact of CuO NPs on hepatocellular carcinoma (HCC) cells, well-differentiated (HepG2) and poorly differentiated (SK-Hep-1) cells were exposed to CuO NPs. Cell viability assay showed that the median inhibition concentration (IC50) for SK-Hep-1 and HepG2 cells was 25 μg ml-1 and 85 μg ml-1, respectively. Cellular fluorescence intensity using DCFH-DA staining analysis revealed significant intracellular reactive oxygen species (ROS) generation of up to 242% in SK-Hep-1 cells, compared with 86% in HepG2 cells. HPLC analysis demonstrated that a CuO NP treatment caused cellular GSH depletion of 58% and a GSH/GSSG ratio decrease to ~0.1 in SK-Hep-1 cells. The oxidative stress caused by enhanced superoxide anion production was observed in both HepG2 (146%) and SK-Hep-1 (192%) cells. The Griess assay verified that CuO NPs induced NO production (170%) in SK-Hep-1 cells. Comet assay and western blot further demonstrated that CuO NPs induced severe DNA strand breakage (70%) in SK-Hep-1 cells and caused DNA damage via increased γ-H2AX levels. These results suggest that well-differentiated HepG2 cells possess a robust antioxidant defense system against CuO NP-induced ROS stress and exhibit more tolerance to oxidative stress. Conversely, poorly differentiated SK-Hep-1 cells exhibited a deregulated antioxidant defense system that allowed accumulation of CuO NP-induced ROS and resulted in severe cytotoxicity.Copper oxide nanoparticles (CuO NPs) are known to exhibit toxic effects on a variety of cell types and organs. To determine the oxidative impact of CuO NPs on hepatocellular carcinoma (HCC) cells, well-differentiated (HepG2) and poorly differentiated (SK-Hep-1) cells were exposed to CuO NPs. Cell viability assay showed that the median inhibition concentration (IC50) for SK-Hep-1 and HepG2 cells was 25 μg ml-1 and 85 μg ml-1, respectively

  2. Reactive oxygen species-driven HIF1α triggers accelerated glycolysis in endothelial cells exposed to low oxygen tension

    International Nuclear Information System (INIS)

    Paik, Jin-Young; Jung, Kyung-Ho; Lee, Jin-Hee; Park, Jin-Won; Lee, Kyung-Han

    2017-01-01

    Endothelial cells and their metabolic state regulate glucose transport into underlying tissues. Here, we show that low oxygen tension stimulates human umbilical vein endothelial cell 18 F–fluorodeoxyglucose ( 18 F–FDG) uptake and lactate production. This was accompanied by augmented hexokinase activity and membrane Glut-1, and increased accumulation of hypoxia-inducible factor-1α (HIF1α). Restoration of oxygen reversed the metabolic effect, but this was blocked by HIF1α stabilization. Hypoxia-stimulated 18 F–FDG uptake was completely abrogated by silencing of HIF1α expression or by a specific inhibitor. There was a rapid and marked increase of reactive oxygen species (ROS) by hypoxia, and ROS scavenging or NADPH oxidase inhibition completely abolished hypoxia-stimulated HIF1α and 18 F–FDG accumulation, placing ROS production upstream of HIF1α signaling. Hypoxia-stimulated HIF1α and 18 F–FDG accumulation was blocked by the protein kinase C (PKC) inhibitor, staurosporine. The phosphatidylinositol 3-kinase (PI3K) inhibitor, wortmannin, blocked hypoxia-stimulated 18 F–FDG uptake and attenuated hypoxia-responsive element binding of HIF1α without influencing its accumulation. Thus, ROS-driven HIF1α accumulation, along with PKC and PI3K signaling, play a key role in triggering accelerated glycolysis in endothelial cells under hypoxia, thereby contributing to 18 F–FDG transport.

  3. Chilli anthracnose disease caused by Colletotrichum species§

    OpenAIRE

    Than, Po Po; Prihastuti, Haryudian; Phoulivong, Sitthisack; Taylor, Paul W.J.; Hyde, Kevin D.

    2008-01-01

    Anthracnose disease is one of the major economic constraints to chilli production worldwide, especially in tropical and subtropical regions. Accurate taxonomic information is necessary for effective disease control management. In the Colletotrichum patho-system, different Colletotrichum species can be associated with anthracnose of the same host. Little information is known concerning the interactions of the species associated with the chilli anthracnose although several Colletotrichum specie...

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

    Science.gov (United States)

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

    2009-01-01

    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...

  5. Lysosome-Targeting Amplifiers of Reactive Oxygen Species as Anticancer Prodrugs

    Czech Academy of Sciences Publication Activity Database

    Daum, S.; Reshetnikov, M.S.V.; Šíša, Miroslav; Dumych, T.; Lootsik, M. D.; Bilyy, R.; Bila, E.; Janko, C.; Alexiou, C.; Herrmann, M.; Sellner, L.; Mokhir, A.

    2017-01-01

    Roč. 56, č. 49 (2017), s. 15545-15549 ISSN 1433-7851 Institutional support: RVO:61389030 Keywords : aminoferrocene * cancer * lysosomes * prodrugs * reactive oxygen species Subject RIV: ED - Physiology OBOR OECD: Organic chemistry Impact factor: 11.994, year: 2016

  6. Herbivore derived fatty acid-amides elicit reactive oxygen species burst in plants

    Science.gov (United States)

    The formation of a reactive oxygen species (ROS) burst is a central response of plants to many forms of stress including pathogen attack, several abiotic stresses, damage and insect infestation. These ROS act as a direct defense as well as signaling and regulatory molecules. Perception of microbe or...

  7. Urbanization causes shifts in species' trait state frequencies

    NARCIS (Netherlands)

    Knapp, S.; Kühn, I.; Wittig, R.; Ozinga, W.A.; Poschlod, P.; Klotz, S.

    2008-01-01

    Urbanization is one of the most extreme forms of land transformation. It is supposed to change the frequencies of species trait states in species assemblages.We hypothesize that the flora of urban and rural areas differs in the frequency of trait states and ask which traits enable a plant to cope

  8. Explorations on Temperature, Oxygen, Nutrients and Habitat Demands of Fish Species Found in River Coruh

    Directory of Open Access Journals (Sweden)

    Bilal Akbulut

    2009-04-01

    Full Text Available For the protection of our natural resources, fish species being economic and ecological richness of the natural in the basin of the Çoruh to know their request is extremely a vital important issue. In this study, temperature and oxygen demand, food and habitat of 18 fish species in six families found in river Çoruh assessed and discussed with the literature and database. Limiting the impact of water temperature on the reproductive, growth and nutrition emphasized. The fish species in the basin spawn at temperatures between 14-30°C according to database. Three species belonging to a family feed with animal food floating in the water. The species belonging to the other families more feed mixed with plant and animal foods diet in the floor or near the ground. Importance of their environmental demands has clarified for conservation and sustainable use of these fish species inhabiting in Çoruh River.

  9. Tuning of redox regulatory mechanisms, reactive oxygen species and redox homeostasis under salinity stress

    Directory of Open Access Journals (Sweden)

    Hossain eSazzad

    2016-05-01

    Full Text Available Soil salinity is a crucial environmental constraint which limits biomass production at many sites on a global scale. Saline growth conditions cause osmotic and ionic imbalances, oxidative stress and perturb metabolism, e.g. the photosynthetic electron flow. The plant ability to tolerate salinity is determined by multiple biochemical and physiological mechanisms protecting cell functions, in particular by regulating proper water relations and maintaining ion homeostasis. Redox homeostasis is a fundamental cell property. Its regulation includes control of reactive oxygen species (ROS generation, sensing deviation from and readjustment of the cellular redox state. All these redox related functions have been recognized as decisive factors in salinity acclimation and adaptation. This review focuses on the core response of plants to overcome the challenges of salinity stress through regulation of ROS generation and detoxification systems and to maintain redox homeostasis. Emphasis is given to the role of NADH oxidase (RBOH, alternative oxidase (AOX, the plastid terminal oxidase (PTOX and the malate valve with the malate dehydrogenase isoforms under salt stress. Overwhelming evidence assigns an essential auxiliary function of ROS and redox homeostasis to salinity acclimation of plants.

  10. Mercuric ions inhibit mitogen-activated protein kinase dephosphorylation by inducing reactive oxygen species

    International Nuclear Information System (INIS)

    Haase, Hajo; Engelhardt, Gabriela; Hebel, Silke; Rink, Lothar

    2011-01-01

    Mercury intoxication profoundly affects the immune system, in particular, signal transduction of immune cells. However, the mechanism of the interaction of mercury with cellular signaling pathways, such as mitogen activated protein kinases (MAPK), remains elusive. Therefore, the objective of this study is to investigate three potential ways in which Hg 2+ ions could inhibit MAPK dephosphorylation in the human T-cell line Jurkat: (1) by direct binding to phosphatases; (2) by releasing cellular zinc (Zn 2+ ); and (3) by inducing reactive oxygen species (ROS). Hg 2+ causes production of ROS, measured by dihydrorhodamine 123, and triggers ROS-mediated Zn 2+ release, detected with FluoZin-3. Yet, phosphatase-inhibition is not mediated by binding of Zn 2+ or Hg 2+ . Rather, phosphatases are inactivated by at least two forms of thiol oxidation; initial inhibition is reversible with reducing agents such as Tris(2-carboxyethyl)phosphine. Prolonged inhibition leads to non-reversible phosphatase oxidation, presumably oxidizing the cysteine thiol to sulfinic- or sulfonic acid. Notably, phosphatases are a particularly sensitive target for Hg 2+ -induced oxidation, because phosphatase activity is inhibited at concentrations of Hg 2+ that have only minor impact on over all thiol oxidation. This phosphatase inhibition results in augmented, ROS-dependent MAPK phosphorylation. MAPK are important regulators of T-cell function, and MAPK-activation by inhibition of phosphatases seems to be one of the molecular mechanisms by which mercury affects the immune system.

  11. Levels of semenogelin in human spermatozoa decrease during capacitation: involvement of reactive oxygen species and zinc.

    Science.gov (United States)

    de Lamirande, E; Lamothe, G

    2010-07-01

    Semenogelin (Sg), the main protein of human semen coagulum, prevents sperm capacitation. The objective of this study was to examine the role of Sg and its mechanism of action. Sg blocked sperm capacitation triggered by various stimuli, via inhibition of superoxide anion (O(2)*-; luminescence assay) and nitric oxide (NO*; tested using diaminofluorescein) generation. Triton-soluble and -insoluble sperm fractions contained Sg and Sg peptides (immunoblotting), the level of which decreased with initiation of capacitation. This drop was prevented by superoxide dismutase and NO* synthase inhibitor and was reproduced by addition of O(2)*- and NO*. Zinc (Zn(2+)) blocked and a zinc chelator (TPEN) promoted the decline in Sg levels. There was a decreased labelling of Sg on the head in capacitating spermatozoa with the two fixation techniques tested (immunocytochemistry). Reactive oxygen species (ROS) (O(2)*- and NO*) caused, these changes, and zinc prevented them. Spermatozoa quickly internalized Sg upon incubation and Sg was then rapidly degraded in a zinc-inhibitable manner. Sg blocked capacitation mainly via inhibition of ROS generation. Spermatozoa appeared permeable to Sg and processed Sg in a zinc-inhibitable fashion. ROS themselves could promote sperm disposal of Sg which maybe one of the mechanisms that allows initiation of capacitation.

  12. Reactive oxygen species are key mediators of the nitric oxide apoptotic pathway in anterior pituitary cells.

    Science.gov (United States)

    Machiavelli, Leticia I; Poliandri, Ariel H; Quinteros, Fernanda A; Cabilla, Jimena P; Duvilanski, Beatriz H

    2007-03-01

    We previously showed that long-term exposure of anterior pituitary cells to nitric oxide (NO) induces apoptosis. The intracellular signals underlying this effect remained unclear. In this study, we searched for possible mechanisms involved in the early stages of the NO apoptotic cascade. Caspase 3 was activated by NO with no apparent disruption of mitochondrial membrane potential. NO caused a rapid increase of reactive oxygen species (ROS), and this increase seems to be dependent of mitochondrial electron transport chain. The antioxidant N-acetyl-cysteine avoided ROS increase, prevented the NO-induced caspase 3 activation, and reduced the NO apoptotic effect. Catalase was inactivated by NO, while glutathione peroxidase (GPx) activity and reduced glutathione (GSH) were not modified at first, but increased at later times of NO exposure. The increase of GSH level is important for the scavenging of the NO-induced ROS overproduction. Our results indicate that ROS have an essential role as a trigger of the NO apoptotic cascade in anterior pituitary cells. The permanent inhibition of catalase may strengthen the oxidative damage induced by NO. GPx activity and GSH level augment in response to the oxidative damage, though this increase seems not to be enough to rescue the cells from the NO effect.

  13. Roles of Reactive Oxygen Species in Anticancer Therapy with Salvia miltiorrhiza Bunge

    Directory of Open Access Journals (Sweden)

    Yu-Chiang Hung

    2016-01-01

    Full Text Available Cancer is a leading cause of death worldwide. We aim to provide a systematic review about the roles of reactive oxygen species (ROS in anticancer therapy with Salvia miltiorrhiza Bunge (Danshen. Danshen, including its lipophilic and hydrophilic constituents, is potentially beneficial for treating various cancers. The mechanisms of ROS-related anticancer effects of Danshen vary depending on the specific type of cancer cells involved. Danshen may enhance TNF-α-induced apoptosis, upregulate caspase-3, caspase-8, caspase-9, endoplasmic reticulum stress, P21, P53, Bax/Bcl-2, DR5, and AMP-activated protein kinase, or activate the p38/JNK, mitogen-activated protein kinase, and FasL signaling pathways. Conversely, Danshen may downregulate human telomerase reverse transcriptase mRNA, telomerase, survivin, vascular endothelial growth factor/vascular endothelial growth factor receptor 2, CD31, NF-κB, Erk1/2, matrix metalloproteinases, microtubule assembly, and receptor tyrosine kinases including epidermal growth factor receptors, HER2, and P-glycoprotein and inhibit the PI3K/Akt/mTOR or estrogen receptor signaling pathways. Therefore, Danshen may inhibit cancer cells proliferation through antioxidation on tumor initiation and induce apoptosis or autophagy through ROS generation on tumor progression, tumor promotion, and tumor metastasis. Based on the available evidence regarding its anticancer properties, this review provides new insights for further anticancer research or clinical trials with Danshen.

  14. Pre-Transplantation Blockade of TNF-α-Mediated Oxygen Species Accumulation Protects Hematopoietic Stem Cells.

    Science.gov (United States)

    Ishida, Takashi; Suzuki, Sachie; Lai, Chen-Yi; Yamazaki, Satoshi; Kakuta, Shigeru; Iwakura, Yoichiro; Nojima, Masanori; Takeuchi, Yasuo; Higashihara, Masaaki; Nakauchi, Hiromitsu; Otsu, Makoto

    2017-04-01

    Hematopoietic stem cell (HSC) transplantation (HSCT) for malignancy requires toxic pre-conditioning to maximize anti-tumor effects and donor-HSC engraftment. While this induces bone marrow (BM)-localized inflammation, how this BM environmental change affects transplanted HSCs in vivo remains largely unknown. We here report that, depending on interval between irradiation and HSCT, residence within lethally irradiated recipient BM compromises donor-HSC reconstitution ability. Both in vivo and in vitro we demonstrate that, among inflammatory cytokines, TNF-α plays a role in HSC damage: TNF-α stimulation leads to accumulation of reactive oxygen species (ROS) in highly purified hematopoietic stem/progenitor cells (HSCs/HSPCs). Transplantation of flow-cytometry-sorted murine HSCs reveals damaging effects of accumulated ROS on HSCs. Short-term incubation either with an specific inhibitor of tumor necrosis factor receptor 1 signaling or an antioxidant N-acetyl-L-cysteine (NAC) prevents TNF-α-mediated ROS accumulation in HSCs. Importantly, pre-transplantation exposure to NAC successfully demonstrats protective effects in inflammatory BM on graft-HSCs, exhibiting better reconstitution capability than that of nonprotected control grafts. We thus suggest that in vivo protection of graft-HSCs from BM inflammation is a feasible and attractive approach, which may lead to improved hematopoietic reconstitution kinetics in transplantation with myeloablative conditioning that inevitably causes inflammation in recipient BM. Stem Cells 2017;35:989-1002. © 2016 The Authors STEM CELLS published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

  15. The epigenetic landscape related to reactive oxygen species formation in the cardiovascular system.

    Science.gov (United States)

    Kietzmann, Thomas; Petry, Andreas; Shvetsova, Antonina; Gerhold, Joachim M; Görlach, Agnes

    2017-06-01

    Cardiovascular diseases are among the leading causes of death worldwide. Reactive oxygen species (ROS) can act as damaging molecules but also represent central hubs in cellular signalling networks. Increasing evidence indicates that ROS play an important role in the pathogenesis of cardiovascular diseases, although the underlying mechanisms and consequences of pathophysiologically elevated ROS in the cardiovascular system are still not completely resolved. More recently, alterations of the epigenetic landscape, which can affect DNA methylation, post-translational histone modifications, ATP-dependent alterations to chromatin and non-coding RNA transcripts, have been considered to be of increasing importance in the pathogenesis of cardiovascular diseases. While it has long been accepted that epigenetic changes are imprinted during development or even inherited and are not changed after reaching the lineage-specific expression profile, it becomes more and more clear that epigenetic modifications are highly dynamic. Thus, they might provide an important link between the actions of ROS and cardiovascular diseases. This review will provide an overview of the role of ROS in modulating the epigenetic landscape in the context of the cardiovascular system. This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc. © 2017 The British Pharmacological Society.

  16. Generation of Reactive Oxygen Species via NOXa Is Important for Development and Pathogenicity of Mycosphaerella graminicola.

    Science.gov (United States)

    Choi, Yoon-E; Lee, Changsu; Goodwin, Stephen B

    2016-03-01

    The ascomycete fungus Mycosphaerella graminicola (synonym Zymoseptoria tritici) is an important pathogen of wheat causing economically significant losses. The primary nutritional mode of this fungus is thought to be hemibiotrophic. This pathogenic lifestyle is associated with an early biotrophic stage of nutrient uptake followed by a necrotrophic stage aided possibly by production of a toxin or reactive oxygen species (ROS). In many other fungi, the genes CREA and AREA are important during the biotrophic stage of infection, while the NOXa gene product is important during necrotrophic growth. To test the hypothesis that these genes are important for pathogenicity of M. graminicola, we employed an over-expression strategy for the selected target genes CREA, AREA, and NOXa, which might function as regulators of nutrient acquisition or ROS generation. Increased expressions of CREA, AREA, and NOXa in M. graminicola were confirmed via quantitative real-time PCR and strains were subsequently assayed for pathogenicity. Among them, the NOXa over-expression strain, NO2, resulted in significantly increased virulence. Moreover, instead of the usual filamentous growth, we observed a predominance of yeast-like growth of NO2 which was correlated with ROS production. Our data indicate that ROS generation via NOXa is important to pathogenicity as well as development in M. graminicola.

  17. Irradiation of skin with visible light induces reactive oxygen species and matrix-degrading enzymes.

    Science.gov (United States)

    Liebel, Frank; Kaur, Simarna; Ruvolo, Eduardo; Kollias, Nikiforos; Southall, Michael D

    2012-07-01

    Daily skin exposure to solar radiation causes cells to produce reactive oxygen species (ROS), which are a primary factor in skin damage. Although the contribution of the UV component to skin damage has been established, few studies have examined the effects of non-UV solar radiation on skin physiology. Solar radiation comprises UV, and thus the purpose of this study was to examine the physiological response of skin to visible light (400-700 nm). Irradiation of human skin equivalents with visible light induced production of ROS, proinflammatory cytokines, and matrix metalloproteinase (MMP)-1 expression. Commercially available sunscreens were found to have minimal effects on reducing visible light-induced ROS, suggesting that UVA/UVB sunscreens do not protect the skin from visible light-induced responses. Using clinical models to assess the generation of free radicals from oxidative stress, higher levels of free radical activity were found after visible light exposure. Pretreatment with a photostable UVA/UVB sunscreen containing an antioxidant combination significantly reduced the production of ROS, cytokines, and MMP expression in vitro, and decreased oxidative stress in human subjects after visible light irradiation. Taken together, these findings suggest that other portions of the solar spectrum aside from UV, particularly visible light, may also contribute to signs of premature photoaging in skin.

  18. Zooplankton Distribution and Species Composition Along an Oxygen Gradient in Puget Sound, WA

    Science.gov (United States)

    Keister, J. E.; Essington, T.; Li, L.; Horne, J. K.; Sato, M.; Parker-Stetter, S. L.; Moriarty, P.

    2016-02-01

    Low dissolved oxygen (hypoxia) is one of the most pronounced, pervasive, and significant disturbances in marine ecosystems, yet our understanding of its effects is incomplete, particularly with respect to impacts on lower trophic levels. As part of a study of how hypoxia affects predator-prey relationships and energy flow through marine food webs, we are studying relationships between ocean chemistry and zooplankton in Puget Sound, Washington—a deep, seasonally hypoxic fjord in the Pacific Northwest that supports a productive and diverse pelagic community. From summer through fall in two years that differed in the timing and intensity of hypoxia, we conducted multi-frequency bioacoustic surveys, CTD casts, and depth-stratified zooplankton sampling to examine changes in distribution and species composition of animals in relation to oxygen concentrations. We exploited a natural gradient in oxygen along the axis of the fjord by sampling at moderately hypoxic and normoxic sites with otherwise similar hydrography and species composition to disentangle the effects of oxygen from changes in other environmental factors. Our results support the hypothesis that zooplankton species composition and vertical distributions are altered by hypoxia, but only when examined at the species and life-stage level. Relatively few taxa showed clear responses to hypoxia, and bioacoustic backscatter data (which was dominated by adult euphausiids and amphipods) indicated that those taxa were not affected by the levels of hypoxia we observed. Examination of net tow data revealed more subtle changes, including behavioral avoidance of low oxygen by some copepods and young euphausiid life stages. Overall, the high species diversity and relatively low susceptibility of many zooplankton to hypoxia in Puget Sound may confer ecosystem resilience to near-future projected changes in this region.

  19. Reactive oxygen species accumulation and homeostasis are involved in plant immunity to an opportunistic fungal pathogen.

    Science.gov (United States)

    Taheri, Parissa; Kakooee, Tahereh

    2017-09-01

    Alternaria blight is a major and destructive disease of potato worldwide. In recent years, A. tenuissima is recognized as the most prevalent species of this phytopathogenic fungus in potato fields of Asian countries, which causes high yield losses every year. Any potato cultivar with complete resistance to this disease is not recognized, so far. Therefore, screening resistance levels of potatoes and identification of plant defense mechanisms against this fungus might be important for designing novel and effective disease management strategies for controlling the disease. In this research, the role of reactive oxygen species, antioxidants, lignin and phenolics in potato basal resistance to A. tenuissima was compared in the partially resistant Ramus and susceptible Bamba cultivars. Priming O 2 - and H 2 O 2 production and enhanced activity of peroxidase (POX) and catalase (CAT) during interaction with A. tenuissima were observed in Ramus cultivar. Application of ROS generating systems and scavengers revealed critical role of O 2 - and H 2 O 2 in potato defense, which was associated with lignification and phenolics production. More OH - and lipid peroxidation in the susceptible Bamba compared to Ramus cultivar showed their negative effects on resistance. Priming the POX and CAT activity, in correlation with upregulation of the corresponding genes was observed in Ramus. The POX and CAT inhibitors increased disease progress, which was related with decreased lignification. This assay demonstrated not only POX-dependency of lignification, but also its dependence on CAT. However, POX had more importance than CAT in potato defense and in lignification. These findings highlight the function of ROS accumulation and homeostasis in potato resistance against A. tenuissima. Copyright © 2017 Elsevier GmbH. All rights reserved.

  20. Electron Paramagnetic Resonance Measurements of Reactive Oxygen Species by Cyclic Hydroxylamine Spin Probes.

    Science.gov (United States)

    Dikalov, Sergey I; Polienko, Yuliya F; Kirilyuk, Igor

    2018-05-20

    Oxidative stress contributes to numerous pathophysiological conditions such as development of cancer, neurodegenerative, and cardiovascular diseases. A variety of measurements of oxidative stress markers in biological systems have been developed; however, many of these methods are not specific, can produce artifacts, and do not directly detect the free radicals and reactive oxygen species (ROS) that cause oxidative stress. Electron paramagnetic resonance (EPR) is a unique tool that allows direct measurements of free radical species. Cyclic hydroxylamines are useful and convenient molecular probes that readily react with ROS to produce stable nitroxide radicals, which can be quantitatively measured by EPR. In this work, we critically review recent applications of various cyclic hydroxylamine spin probes in biology to study oxidative stress, their advantages, and the shortcomings. Recent Advances: In the past decade, a number of new cyclic hydroxylamine spin probes have been developed and their successful application for ROS measurement using EPR has been published. These new state-of-the-art methods provide improved selectivity and sensitivity for in vitro and in vivo studies. Although cyclic hydroxylamine spin probes EPR application has been previously described, there has been lack of translation of these new methods into biomedical research, limiting their widespread use. This work summarizes "best practice" in applications of cyclic hydroxylamine spin probes to assist with EPR studies of oxidative stress. Additional studies to advance hydroxylamine spin probes from the "basic science" to biomedical applications are needed and could lead to better understanding of pathological conditions associated with oxidative stress. Antioxid. Redox Signal. 28, 1433-1443.

  1. Mitochondrial Reactive Oxygen Species (ROS) and ROS-Induced ROS Release

    Science.gov (United States)

    Zorov, Dmitry B.; Juhaszova, Magdalena; Sollott, Steven J.

    2014-01-01

    Byproducts of normal mitochondrial metabolism and homeostasis include the buildup of potentially damaging levels of reactive oxygen species (ROS), Ca2+, etc., which must be normalized. Evidence suggests that brief mitochondrial permeability transition pore (mPTP) openings play an important physiological role maintaining healthy mitochondria homeostasis. Adaptive and maladaptive responses to redox stress may involve mitochondrial channels such as mPTP and inner membrane anion channel (IMAC). Their activation causes intra- and intermitochondrial redox-environment changes leading to ROS release. This regenerative cycle of mitochondrial ROS formation and release was named ROS-induced ROS release (RIRR). Brief, reversible mPTP opening-associated ROS release apparently constitutes an adaptive housekeeping function by the timely release from mitochondria of accumulated potentially toxic levels of ROS (and Ca2+). At higher ROS levels, longer mPTP openings may release a ROS burst leading to destruction of mitochondria, and if propagated from mitochondrion to mitochondrion, of the cell itself. The destructive function of RIRR may serve a physiological role by removal of unwanted cells or damaged mitochondria, or cause the pathological elimination of vital and essential mitochondria and cells. The adaptive release of sufficient ROS into the vicinity of mitochondria may also activate local pools of redox-sensitive enzymes involved in protective signaling pathways that limit ischemic damage to mitochondria and cells in that area. Maladaptive mPTP- or IMAC-related RIRR may also be playing a role in aging. Because the mechanism of mitochondrial RIRR highlights the central role of mitochondria-formed ROS, we discuss all of the known ROS-producing sites (shown in vitro) and their relevance to the mitochondrial ROS production in vivo. PMID:24987008

  2. E-Cigarette Aerosol Exposure Induces Reactive Oxygen Species, DNA Damage, and Cell Death in Vascular Endothelial Cells.

    Science.gov (United States)

    Anderson, Chastain; Majeste, Andrew; Hanus, Jakub; Wang, Shusheng

    2016-12-01

    Cigarette smoking remains one of the leading causes of preventable death worldwide. Vascular cell death and dysfunction is a central or exacerbating component in the majority of cigarette smoking related pathologies. The recent development of the electronic nicotine delivery systems known as e-cigarettes provides an alternative to conventional cigarette smoking; however, the potential vascular health risks of e-cigarette use remain unclear. This study evaluates the effects of e-cigarette aerosol extract (EAE) and conventional cigarette smoke extract (CSE) on human umbilical vein endothelial cells (HUVECs). A laboratory apparatus was designed to produce extracts from e-cigarettes and conventional cigarettes according to established protocols for cigarette smoking. EAE or conventional CSE was applied to human vascular endothelial cells for 4-72 h, dependent on the assay. Treated cells were assayed for reactive oxygen species, DNA damage, cell viability, and markers of programmed cell death pathways. Additionally, the anti-oxidants α-tocopherol and n-acetyl-l-cysteine were used to attempt to rescue e-cigarette induced cell death. Our results indicate that e-cigarette aerosol is capable of inducing reactive oxygen species, causing DNA damage, and significantly reducing cell viability in a concentration dependent fashion. Immunofluorescent and flow cytometry analysis indicate that both the apoptosis and programmed necrosis pathways are triggered by e-cigarette aerosol treatment. Additionally, anti-oxidant treatment provides a partial rescue of the induced cell death, indicating that reactive oxygen species play a causal role in e-cigarette induced cytotoxicity. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  3. Crosstalk between nitrite, myoglobin and reactive oxygen species to regulate vasodilation under hypoxia.

    Directory of Open Access Journals (Sweden)

    Matthias Totzeck

    Full Text Available The systemic response to decreasing oxygen levels is hypoxic vasodilation. While this mechanism has been known for more than a century, the underlying cellular events have remained incompletely understood. Nitrite signaling is critically involved in vessel relaxation under hypoxia. This can be attributed to the presence of myoglobin in the vessel wall together with other potential nitrite reductases, which generate nitric oxide, one of the most potent vasodilatory signaling molecules. Questions remain relating to the precise concentration of nitrite and the exact dose-response relations between nitrite and myoglobin under hypoxia. It is furthermore unclear whether regulatory mechanisms exist which balance this interaction. Nitrite tissue levels were similar across all species investigated. We then investigated the exact fractional myoglobin desaturation in an ex vivo approach when gassing with 1% oxygen. Within a short time frame myoglobin desaturated to 58±12%. Given that myoglobin significantly contributes to nitrite reduction under hypoxia, dose-response experiments using physiological to pharmacological nitrite concentrations were conducted. Along all concentrations, abrogation of myoglobin in mice impaired vasodilation. As reactive oxygen species may counteract the vasodilatory response, we used superoxide dismutase and its mimic tempol as well as catalase and ebselen to reduce the levels of reactive oxygen species during hypoxic vasodilation. Incubation of tempol in conjunction with catalase alone and catalase/ebselen increased the vasodilatory response to nitrite. Our study shows that modest hypoxia leads to a significant nitrite-dependent vessel relaxation. This requires the presence of vascular myoglobin for both physiological and pharmacological nitrite levels. Reactive oxygen species, in turn, modulate this vasodilation response.

  4. Species Adulteration in the Herbal Trade: Causes, Consequences and Mitigation.

    Science.gov (United States)

    Srirama, Ramanujam; Santhosh Kumar, J U; Seethapathy, G S; Newmaster, Steven G; Ragupathy, S; Ganeshaiah, K N; Uma Shaanker, R; Ravikanth, Gudasalamani

    2017-08-01

    The global economy of the international trade of herbal products has been increasing by 15% annually, with the raw material for most herbal products being sourced from South and Southeast Asian countries. In India, of the 8000 species of medicinal plants harvested from the wild, approximately 960 are in the active trade. With increasing international trade in herbal medicinal products, there is also increasing concern about the widespread adulteration and species admixtures in the raw herbal trade. The adverse consequences of such species adulteration on the health and safety of consumers have only recently begun to be recognised and documented. We provide a comprehensive review of the nature and magnitude of species adulteration in the raw herbal trade, and identify the underlying drivers that might lead to such adulteration. We also discuss the possible biological and chemical equivalence of species that are used as adulterants and substitutes, and the consequences thereof to consumer health and safety, and propose a framework for the development of a herbal trade authentication service that can help regulate the herbal trade market.

  5. Diagnostics of Tree Diseases Caused by Phytophthora austrocedri Species.

    Science.gov (United States)

    Mulholland, Vincent; Elliot, Matthew; Green, Sarah

    2015-01-01

    We present methods for the detection and quantification of four Phytophthora species which are pathogenic on trees; Phytophthora ramorum, Phytophthora kernoviae, Phytophthora lateralis, and Phytophthora austrocedri. Nucleic acid extraction methods are presented for phloem tissue from trees, soil, and pure cultures on agar plates. Real-time PCR methods are presented and include primer and probe sets for each species, general advice on real-time PCR setup and data analysis. A method for sequence-based identification, useful for pure cultures, is also included.

  6. Comparison of stainless and mild steel welding fumes in generation of reactive oxygen species

    Directory of Open Access Journals (Sweden)

    Frazer David

    2010-11-01

    Full Text Available Abstract Background Welding fumes consist of a wide range of complex metal oxide particles which can be deposited in all regions of the respiratory tract. The welding aerosol is not homogeneous and is generated mostly from the electrode/wire. Over 390,000 welders were reported in the U.S. in 2008 while over 1 million full-time welders were working worldwide. Many health effects are presently under investigation from exposure to welding fumes. Welding fume pulmonary effects have been associated with bronchitis, metal fume fever, cancer and functional changes in the lung. Our investigation focused on the generation of free radicals and reactive oxygen species from stainless and mild steel welding fumes generated by a gas metal arc robotic welder. An inhalation exposure chamber located at NIOSH was used to collect the welding fume particles. Results Our results show that hydroxyl radicals (.OH were generated from reactions with H2O2 and after exposure to cells. Catalase reduced the generation of .OH from exposed cells indicating the involvement of H2O2. The welding fume suspension also showed the ability to cause lipid peroxidation, effect O2 consumption, induce H2O2 generation in cells, and cause DNA damage. Conclusion Increase in oxidative damage observed in the cellular exposures correlated well with .OH generation in size and type of welding fumes, indicating the influence of metal type and transition state on radical production as well as associated damage. Our results demonstrate that both types of welding fumes are able to generate ROS and ROS-related damage over a range of particle sizes; however, the stainless steel fumes consistently showed a significantly higher reactivity and radical generation capacity. The chemical composition of the steel had a significant impact on the ROS generation capacity with the stainless steel containing Cr and Ni causing more damage than the mild steel. Our results suggest that welding fumes may cause acute

  7. Post-operative Wound Site Infection Caused by Nocardia species

    Directory of Open Access Journals (Sweden)

    Sunayana M. Jangla

    2018-04-01

    Full Text Available A61 year old diabetic female who was a known case of breast carcinoma and had undergone mastectomy was admitted with discharge from the post-operative wound site. Nocardia species was isolated from the discharge. She responded to treatment with trimethoprim-sulfamethoxazole.

  8. Characterisation of Neofusicoccum species causing mango dieback in Italy

    NARCIS (Netherlands)

    Ismail, A.; Cirvilleri, G.; Lombard, L.; Crous, P.W.; Groenewald, J.Z.; Polizzi, G.

    2013-01-01

    Species of Botryosphaeriaceae are important fungal pathogens of mango worldwide. A survey of 11 mango orchards located in the provinces of Catania, Messina, Palermo and Ragusa (Sicily, southern Italy), resulted in the isolation of a large number (76) of Neofusicoccum isolates associated with decline

  9. First human-caused extinction of a cetacean species?

    Science.gov (United States)

    Turvey, Samuel T; Pitman, Robert L; Taylor, Barbara L; Barlow, Jay; Akamatsu, Tomonari; Barrett, Leigh A; Zhao, Xiujiang; Reeves, Randall R; Stewart, Brent S; Wang, Kexiong; Wei, Zhuo; Zhang, Xianfeng; Pusser, L T; Richlen, Michael; Brandon, John R; Wang, Ding

    2007-10-22

    The Yangtze River dolphin or baiji (Lipotes vexillifer), an obligate freshwater odontocete known only from the middle-lower Yangtze River system and neighbouring Qiantang River in eastern China, has long been recognized as one of the world's rarest and most threatened mammal species. The status of the baiji has not been investigated since the late 1990s, when the surviving population was estimated to be as low as 13 individuals. An intensive six-week multi-vessel visual and acoustic survey carried out in November-December 2006, covering the entire historical range of the baiji in the main Yangtze channel, failed to find any evidence that the species survives. We are forced to conclude that the baiji is now likely to be extinct, probably due to unsustainable by-catch in local fisheries. This represents the first global extinction of a large vertebrate for over 50 years, only the fourth disappearance of an entire mammal family since AD 1500, and the first cetacean species to be driven to extinction by human activity. Immediate and extreme measures may be necessary to prevent the extinction of other endangered cetaceans, including the sympatric Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis).

  10. Release of intracellular Calcium increase production of mitochondrial reactive oxygen species in renal distal epithelial cells

    DEFF Research Database (Denmark)

    Bjerregaard, Henning F.

    peroxide (H2O2) has traditionally been regarded as toxic by-products of aerobic metabolism. However, recent findings indicate that H2O2 act as a signalling molecule. The aim of the present study was to monitor, in real time, the rates of ROS generation in order to directly determine their production......Release of intracellular Calcium increase production of mitochondrial reactive oxygen species in renal distal epithelial cells. Henning F. Bjerregaard, Roskilde University, Department of Science, Systems and Models , 4000 Roskilde, Denmark. HFB@ RUC.DK Reactive oxygen species (ROS) like, hydrogen...... to G-protein stimulation of phospholipase C and release of inositol -3 phosphate. Cd (0.4 mM) treatment of A6 cells enhanced the ROS production after one minutes incubation. The production rate was constant for at least 10 to 20 min. Experiments showed that the Cd induced increase in ROS production...

  11. Staphyloxanthin photobleaching sensitizes methicillin-resistant Staphylococcus aureus to reactive oxygen species attack

    Science.gov (United States)

    Dong, Pu-Ting; Mohammad, Haroon; Hui, Jie; Wang, Xiaoyu; Li, Junjie; Liang, Lijia; Seleem, Mohamed N.; Cheng, Ji-Xin

    2018-02-01

    Given that the dearth of new antibiotic development loads an existential burden on successful infectious disease therapy, health organizations are calling for alternative approaches to combat methicillin-resistant Staphylococcus aureus (MRSA) infections. Here, we report a drug-free photonic approach to eliminate MRSA through photobleaching of staphyloxanthin, an indispensable membrane-bound antioxidant of S. aureus. The photobleaching process, uncovered through a transient absorption imaging study and quantitated by absorption spectroscopy and mass spectrometry, decomposes staphyloxanthin, and sensitizes MRSA to reactive oxygen species attack. Consequently, staphyloxanthin bleaching by low-level blue light eradicates MRSA synergistically with external or internal reactive oxygen species. The effectiveness of this synergistic therapy is validated in MRSA culture, MRSAinfected macrophage cells. Collectively, these findings highlight broad applications of staphyloxanthin photobleaching for treatment of MRSA infections.

  12. Identification of different oxygen species in oxide nanostructures with 17O solid-state NMR spectroscopy

    Science.gov (United States)

    Wang, Meng; Wu, Xin-Ping; Zheng, Sujuan; Zhao, Li; Li, Lei; Shen, Li; Gao, Yuxian; Xue, Nianhua; Guo, Xuefeng; Huang, Weixin; Gan, Zhehong; Blanc, Frédéric; Yu, Zhiwu; Ke, Xiaokang; Ding, Weiping; Gong, Xue-Qing; Grey, Clare P.; Peng, Luming

    2015-01-01

    Nanostructured oxides find multiple uses in a diverse range of applications including catalysis, energy storage, and environmental management, their higher surface areas, and, in some cases, electronic properties resulting in different physical properties from their bulk counterparts. Developing structure-property relations for these materials requires a determination of surface and subsurface structure. Although microscopy plays a critical role owing to the fact that the volumes sampled by such techniques may not be representative of the whole sample, complementary characterization methods are urgently required. We develop a simple nuclear magnetic resonance (NMR) strategy to detect the first few layers of a nanomaterial, demonstrating the approach with technologically relevant ceria nanoparticles. We show that the 17O resonances arising from the first to third surface layer oxygen ions, hydroxyl sites, and oxygen species near vacancies can be distinguished from the oxygen ions in the bulk, with higher-frequency 17O chemical shifts being observed for the lower coordinated surface sites. H217O can be used to selectively enrich surface sites, allowing only these particular active sites to be monitored in a chemical process. 17O NMR spectra of thermally treated nanosized ceria clearly show how different oxygen species interconvert at elevated temperature. Density functional theory calculations confirm the assignments and reveal a strong dependence of chemical shift on the nature of the surface. These results open up new strategies for characterizing nanostructured oxides and their applications. PMID:26601133

  13. Ratiometric reactive oxygen species nanoprobe for noninvasive in vivo imaging of subcutaneous inflammation/infection

    OpenAIRE

    Zhou, Jun; Weng, Hong; Huang, Yihui; Gu, Yueqing; Tang, Liping; Hu, Wenjing

    2016-01-01

    Release of reactive oxygen species (ROS) accompanied with acute inflammation and infection often results in cell death and tissue injury. Several ROS-reactive bioluminescent probes have been investigated in recent years to detect ROS activity in vivo. Unfortunately, these probes cannot be used to quantify the degree of ROS activity and inflammatory responses due to the fact that the extent of the bioluminescent signals is also probe-concentration dependent. To address this challenge, we fabri...

  14. Real-time in vivo detection of biomaterial-induced reactive oxygen species

    OpenAIRE

    Liu, Wendy F.; Ma, Minglin; Bratlie, Kaitlin M.; Dang, Tram T.; Langer, Robert; Anderson, Daniel G.

    2010-01-01

    The non-specific host response to implanted biomaterials is often a key challenge of medical device design. To evaluate biocompatibility, measuring the release of reactive oxygen species (ROS) produced by inflammatory cells in response to biomaterial surfaces is a well-established method. However, the detection of ROS in response to materials implanted in vivo has not yet been demonstrated. Here, we develop a bioluminescence whole animal imaging approach to observe ROS released in response to...

  15. Reactive oxygen species formation during tetanic contractions in single isolated Xenopus myofibers

    OpenAIRE

    Zuo, Li; Nogueira, Leonardo; Hogan, Michael C.

    2011-01-01

    Contracting skeletal muscle produces reactive oxygen species (ROS) that have been shown to affect muscle function and adaptation. However, real-time measurement of ROS in contracting myofibers has proven to be difficult. We used amphibian (Xenopus laevis) muscle to test the hypothesis that ROS are formed during contractile activity in isolated single skeletal muscle fibers and that this contraction-induced ROS formation affects fatigue development. Single myofibers were loaded with 5 μM dihyd...

  16. Low Po2 conditions induce reactive oxygen species formation during contractions in single skeletal muscle fibers

    OpenAIRE

    Zuo, Li; Shiah, Amy; Roberts, William J.; Chien, Michael T.; Wagner, Peter D.; Hogan, Michael C.

    2013-01-01

    Contractions in whole skeletal muscle during hypoxia are known to generate reactive oxygen species (ROS); however, identification of real-time ROS formation within isolated single skeletal muscle fibers has been challenging. Consequently, there is no convincing evidence showing increased ROS production in intact contracting fibers under low Po2 conditions. Therefore, we hypothesized that intracellular ROS generation in single contracting skeletal myofibers increases during low Po2 compared wi...

  17. Global Inhibition of Reactive Oxygen Species (ROS) Inhibits Paclitaxel-Induced Painful Peripheral Neuropathy

    OpenAIRE

    Fidanboylu, Mehmet; Griffiths, Lisa A.; Flatters, Sarah J. L.

    2011-01-01

    Paclitaxel (Taxol (R)) is a widely used chemotherapeutic agent that has a major dose limiting side-effect of painful peripheral neuropathy. Currently there is no effective therapy for the prevention or treatment of chemotherapy-induced painful peripheral neuropathies. Evidence for mitochondrial dysfunction during paclitaxel-induced pain was previously indicated with the presence of swollen and vacuolated neuronal mitochondria. As mitochondria are a major source of reactive oxygen species (ROS...

  18. The scavenging effects of tea polyphenol and quercetin on active oxygen species

    International Nuclear Information System (INIS)

    Fang Ruoying; Cheng Jiwu; Hu Tianxi; Tu Tiechen; Dong Jirong; Wang Wenfeng; Lin Nianyun

    1993-01-01

    The abilities of scavenging active oxygen species, O 2 free radical and OH., by tea polyphenols and quercetin have been studied by chemiluminescence, ESR and pulse radiolysis. Tea polyphenols and quercetin are all phenolic antioxidants. The synergetic studies show that both tea polyphenols and quercetin are strong free radical scavengers. Tea polyphenols are better than quercetin. the results from CL studies are in good accord with those from ESR and PR studies

  19. Respiratory adaptations to oxygen lack in three species of Glossiphoniidae (Hirudinea) in Lake Esrom, Denmark

    DEFF Research Database (Denmark)

    Pohle, B. D.; Hamburger, K.

    2005-01-01

    The weight-specific respiration rate (µl O2 mg-1 AFDW h-1) of three species of leech from Lake Esrom, Denmark, Glossiphonia concolor, G. complanata and Helobdella stagnalis was measured in a closed stirred chamber with a micro electrode. At declining oxygen concentration (mg O2 l-1) all three spe...... at 10 and 20 °C, respectively. The results were discussed in relation to habitat and spatial distribution of the three species in the lake....

  20. Atmospheric plasma generates oxygen atoms as oxidizing species in aqueous solutions

    Czech Academy of Sciences Publication Activity Database

    Hefny, M.M.; Pattyn, C.; Lukeš, Petr; Benedikt, J.

    2016-01-01

    Roč. 49, č. 40 (2016), s. 404002 ISSN 0022-3727 R&D Projects: GA MŠk(CZ) LD14080 Grant - others:European Cooperation in Science and Technology(XE) COST TD1208 Institutional support: RVO:61389021 Keywords : atmospheric pressure plasma * transport of reactive species * reactive oxygen species * aqueous phase chemistry * plasma and liquids * phenol aqueous chemistry Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.588, year: 2016 http://iopscience.iop.org/article/10.1088/0022-3727/49/40/404002

  1. Furfural induces reactive oxygen species accumulation and cellular damage in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Slininger Patricia J

    2010-01-01

    Full Text Available Abstract Background Biofuels offer a viable alternative to petroleum-based fuel. However, current methods are not sufficient and the technology required in order to use lignocellulosic biomass as a fermentation substrate faces several challenges. One challenge is the need for a robust fermentative microorganism that can tolerate the inhibitors present during lignocellulosic fermentation. These inhibitors include the furan aldehyde, furfural, which is released as a byproduct of pentose dehydration during the weak acid pretreatment of lignocellulose. In order to survive in the presence of furfural, yeast cells need not only to reduce furfural to the less toxic furan methanol, but also to protect themselves and repair any damage caused by the furfural. Since furfural tolerance in yeast requires a functional pentose phosphate pathway (PPP, and the PPP is associated with reactive oxygen species (ROS tolerance, we decided to investigate whether or not furfural induces ROS and its related cellular damage in yeast. Results We demonstrated that furfural induces the accumulation of ROS in Saccharomyces cerevisiae. In addition, furfural was shown to cause cellular damage that is consistent with ROS accumulation in cells which includes damage to mitochondria and vacuole membranes, the actin cytoskeleton and nuclear chromatin. The furfural-induced damage is less severe when yeast are grown in a furfural concentration (25 mM that allows for eventual growth after an extended lag compared to a concentration of furfural (50 mM that prevents growth. Conclusion These data suggest that when yeast cells encounter the inhibitor furfural, they not only need to reduce furfural into furan methanol but also to protect themselves from the cellular effects of furfural and repair any damage caused. The reduced cellular damage seen at 25 mM furfural compared to 50 mM furfural may be linked to the observation that at 25 mM furfural yeast were able to exit the furfural

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

    Science.gov (United States)

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

    2012-02-01

    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.

  3. Neuroprotection of taurine against reactive oxygen species is associated with inhibiting NADPH oxidases.

    Science.gov (United States)

    Han, Zhou; Gao, Li-Yan; Lin, Yu-Hui; Chang, Lei; Wu, Hai-Yin; Luo, Chun-Xia; Zhu, Dong-Ya

    2016-04-15

    It is well established that taurine shows potent protection against glutamate-induced injury to neurons in stroke. The neuroprotection may result from multiple mechanisms. Increasing evidences suggest that NADPH oxidases (Nox), the primary source of superoxide induced by N-methyl-d-aspartate (NMDA) receptor activation, are involved in the process of oxidative stress. We found that 100μM NMDA induced oxidative stress by increasing the reactive oxygen species level, which contributed to the cell death, in vitro. Neuron cultures pretreated with 25mM taurine showed lower percentage of death cells and declined reactive oxygen species level. Moreover, taurine attenuated Nox2/Nox4 protein expression and enzyme activity and declined intracellular calcium intensity during NMDA-induced neuron injury. Additionally, taurine also showed neuroprotection against H2O2-induced injury, accompanying with Nox inhibition. So, we suppose that protection of taurine against reactive oxygen species during NMDA-induced neuron injury is associated with Nox inhibition, probably in a calcium-dependent manner. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Nitric Oxide is Required for Homeostasis of Oxygen and Reactive Oxygen Species in Barley Roots under Aerobic Conditions

    DEFF Research Database (Denmark)

    Gupta, Kapuganti J; Hebelstrup, Kim; Kruger, Nicholas J

    2014-01-01

    Oxygen, the terminal electron acceptor for mitochondrial electron transport, is vital for plants because of its role in the production of ATP by oxidative phosphorylation. While photosynthetic oxygen production contributes to the oxygen supply in leaves, reducing the risk of oxygen limitation of ...... electron transport chain (Gupta et al., 2011). Thus, NO could influence oxygen consumption under normal aerobic conditions in roots, and it is this specific function that is assessed here.......Oxygen, the terminal electron acceptor for mitochondrial electron transport, is vital for plants because of its role in the production of ATP by oxidative phosphorylation. While photosynthetic oxygen production contributes to the oxygen supply in leaves, reducing the risk of oxygen limitation...

  5. Integration of intracellular telomerase monitoring by electrochemiluminescence technology and targeted cancer therapy by reactive oxygen species.

    Science.gov (United States)

    Zhang, Huairong; Li, Binxiao; Sun, Zhaomei; Zhou, Hong; Zhang, Shusheng

    2017-12-01

    Cancer therapies based on reactive oxygen species (ROS) have emerged as promising clinical treatments. Electrochemiluminescence (ECL) technology has also attracted considerable attention in the field of clinical diagnosis. However, studies about the integration of ECL diagnosis and ROS cancer therapy are very rare. Here we introduce a novel strategy that employs ECL technology and ROS to fill the above vacancy. Briefly, an ITO electrode was electrodeposited with polyluminol-Pt NPs composite films and modified with aptamer DNA to capture HL-60 cancer cells with high specificity. After that, mesoporous silica nanoparticles (MSNs) filled with phorbol 12-myristate 13-acetate (PMA) were closed by the telomerase primer DNA (T-primer DNA) and aptamer. After aptamer on MSN@PMA recognized and combined with the HL-60 cancer cells with high specificity, T-primer DNA on MSN@PMA could be moved away from the MSN@PMA surface after extension by telomerase in the HL-60 cancer cells and PMA was released to induce the production of ROS by the HL-60 cancer cells. After that, the polyluminol-Pt NPs composite films could react with hydrogen peroxide (a major ROS) and generate an ECL signal. Thus the intracellular telomerase activity of the HL-60 cancer cells could be detected in situ . Besides, ROS could induce apoptosis in the HL-60 cancer cells with high efficacy by causing oxidative damage to the lipids, protein, and DNA. Above all, the designed platform could not only detect intracellular telomerase activity instead of that of extracted telomerase, but could also kill targeted tumors by ECL technology and ROS.

  6. Roles of mitochondrial fragmentation and reactive oxygen species in mitochondrial dysfunction and myocardial insulin resistance

    International Nuclear Information System (INIS)

    Watanabe, Tomoyuki; Saotome, Masao; Nobuhara, Mamoru; Sakamoto, Atsushi; Urushida, Tsuyoshi; Katoh, Hideki; Satoh, Hiroshi; Funaki, Makoto; Hayashi, Hideharu

    2014-01-01

    Purpose: Evidence suggests an association between aberrant mitochondrial dynamics and cardiac diseases. Because myocardial metabolic deficiency caused by insulin resistance plays a crucial role in heart disease, we investigated the role of dynamin-related protein-1 (DRP1; a mitochondrial fission protein) in the pathogenesis of myocardial insulin resistance. Methods and Results: DRP1-expressing H9c2 myocytes, which had fragmented mitochondria with mitochondrial membrane potential (ΔΨ m ) depolarization, exhibited attenuated insulin signaling and 2-deoxy-D-glucose (2-DG) uptake, indicating insulin resistance. Treatment of the DRP1-expressing myocytes with Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride (TMPyP) significantly improved insulin resistance and mitochondrial dysfunction. When myocytes were exposed to hydrogen peroxide (H 2 O 2 ), they increased DRP1 expression and mitochondrial fragmentation, resulting in ΔΨ m depolarization and insulin resistance. When DRP1 was suppressed by siRNA, H 2 O 2 -induced mitochondrial dysfunction and insulin resistance were restored. Our results suggest that a mutual enhancement between DRP1 and reactive oxygen species could induce mitochondrial dysfunction and myocardial insulin resistance. In palmitate-induced insulin-resistant myocytes, neither DRP1-suppression nor TMPyP restored the ΔΨ m depolarization and impaired 2-DG uptake, however they improved insulin signaling. Conclusions: A mutual enhancement between DRP1 and ROS could promote mitochondrial dysfunction and inhibition of insulin signal transduction. However, other mechanisms, including lipid metabolite-induced mitochondrial dysfunction, may be involved in palmitate-induced insulin resistance. - Highlights: • DRP1 promotes mitochondrial fragmentation and insulin-resistance. • A mutual enhancement between DRP1 and ROS ipromotes insulin-resistance. • Palmitate increases DRP1 expression and induces insulin-resistance. • Inhibition of DRP or ROS

  7. Roles of mitochondrial fragmentation and reactive oxygen species in mitochondrial dysfunction and myocardial insulin resistance

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Tomoyuki [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan); Saotome, Masao, E-mail: msaotome@hama-med.ac.jp [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan); Nobuhara, Mamoru; Sakamoto, Atsushi; Urushida, Tsuyoshi; Katoh, Hideki; Satoh, Hiroshi [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan); Funaki, Makoto [Clinical Research Center for Diabetes, Tokushima University Hospital, 2-50-1 Kuramoto-cho, Tokushima 770-8503 (Japan); Hayashi, Hideharu [Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192 (Japan)

    2014-05-01

    Purpose: Evidence suggests an association between aberrant mitochondrial dynamics and cardiac diseases. Because myocardial metabolic deficiency caused by insulin resistance plays a crucial role in heart disease, we investigated the role of dynamin-related protein-1 (DRP1; a mitochondrial fission protein) in the pathogenesis of myocardial insulin resistance. Methods and Results: DRP1-expressing H9c2 myocytes, which had fragmented mitochondria with mitochondrial membrane potential (ΔΨ{sub m}) depolarization, exhibited attenuated insulin signaling and 2-deoxy-D-glucose (2-DG) uptake, indicating insulin resistance. Treatment of the DRP1-expressing myocytes with Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride (TMPyP) significantly improved insulin resistance and mitochondrial dysfunction. When myocytes were exposed to hydrogen peroxide (H{sub 2}O{sub 2}), they increased DRP1 expression and mitochondrial fragmentation, resulting in ΔΨ{sub m} depolarization and insulin resistance. When DRP1 was suppressed by siRNA, H{sub 2}O{sub 2}-induced mitochondrial dysfunction and insulin resistance were restored. Our results suggest that a mutual enhancement between DRP1 and reactive oxygen species could induce mitochondrial dysfunction and myocardial insulin resistance. In palmitate-induced insulin-resistant myocytes, neither DRP1-suppression nor TMPyP restored the ΔΨ{sub m} depolarization and impaired 2-DG uptake, however they improved insulin signaling. Conclusions: A mutual enhancement between DRP1 and ROS could promote mitochondrial dysfunction and inhibition of insulin signal transduction. However, other mechanisms, including lipid metabolite-induced mitochondrial dysfunction, may be involved in palmitate-induced insulin resistance. - Highlights: • DRP1 promotes mitochondrial fragmentation and insulin-resistance. • A mutual enhancement between DRP1 and ROS ipromotes insulin-resistance. • Palmitate increases DRP1 expression and induces insulin

  8. PKCα promotes generation of reactive oxygen species via DUOX2 in hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Wang, Jiajun; Shao, Miaomiao; Liu, Min; Peng, Peike; Li, Lili; Wu, Weicheng; Wang, Lan; Duan, Fangfang; Zhang, Mingming; Song, Shushu; Jia, Dongwei; Ruan, Yuanyuan; Gu, Jianxin

    2015-01-01

    Hepatocellular carcinoma (HCC) remains the second leading cause of cancer-related death worldwide, and elevated rates of reactive oxygen species (ROS) have long been considered as a hallmark of almost all types of cancer including HCC. Protein kinase C alpha (PKCα), a serine/threonine kinase among conventional PKC family, is recognized as a major player in signal transduction and tumor progression. Overexpression of PKCα is commonly observed in human HCC and associated with its poor prognosis. However, how PKCα is involved in hepatocellular carcinogenesis remains not fully understood. In this study, we found that among the members of conventional PKC family, PKCα, but not PKCβI or βII, promoted ROS production in HCC cells. PKCα stimulated generation of ROS by up-regulating DUOX2 at post-transcriptional level. Depletion of DUOX2 abrogated PKCα-induced activation of AKT/MAPK pathways as well as cell proliferation, migration and invasion in HCC cells. Moreover, the expression of DUOX2 and PKCα was well positively correlated in both HCC cell lines and patient samples. Collectively, our findings demonstrate that PKCα plays a critical role in HCC development by inducing DUOX2 expression and ROS generation, and propose a strategy to target PKCα/DUOX2 as a potential adjuvant therapy for HCC treatment. - Highlights: • PKCα promotes the generation of ROS in hepatocellular carcinoma. • PKCα induces ROS production by up-regulating DUOX2 at post-transcriptional level. • DUOX2 is required for PKCα-induced AKT/MAPK activation and tumor progression in HCC. • The expression of PKCα is positively correlated with DUOX2 in HCC

  9. Convergent Evolution of Pathogen Effectors toward Reactive Oxygen Species Signaling Networks in Plants.

    Science.gov (United States)

    Jwa, Nam-Soo; Hwang, Byung Kook

    2017-01-01

    Microbial pathogens have evolved protein effectors to promote virulence and cause disease in host plants. Pathogen effectors delivered into plant cells suppress plant immune responses and modulate host metabolism to support the infection processes of pathogens. Reactive oxygen species (ROS) act as cellular signaling molecules to trigger plant immune responses, such as pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity. In this review, we discuss recent insights into the molecular functions of pathogen effectors that target multiple steps in the ROS signaling pathway in plants. The perception of PAMPs by pattern recognition receptors leads to the rapid and strong production of ROS through activation of NADPH oxidase Respiratory Burst Oxidase Homologs (RBOHs) as well as peroxidases. Specific pathogen effectors directly or indirectly interact with plant nucleotide-binding leucine-rich repeat receptors to induce ROS production and the hypersensitive response in plant cells. By contrast, virulent pathogens possess effectors capable of suppressing plant ROS bursts in different ways during infection. PAMP-triggered ROS bursts are suppressed by pathogen effectors that target mitogen-activated protein kinase cascades. Moreover, pathogen effectors target vesicle trafficking or metabolic priming, leading to the suppression of ROS production. Secreted pathogen effectors block the metabolic coenzyme NADP-malic enzyme, inhibiting the transfer of electrons to the NADPH oxidases (RBOHs) responsible for ROS generation. Collectively, pathogen effectors may have evolved to converge on a common host protein network to suppress the common plant immune system, including the ROS burst and cell death response in plants.

  10. Convergent Evolution of Pathogen Effectors toward Reactive Oxygen Species Signaling Networks in Plants

    Directory of Open Access Journals (Sweden)

    Nam-Soo Jwa

    2017-09-01

    Full Text Available Microbial pathogens have evolved protein effectors to promote virulence and cause disease in host plants. Pathogen effectors delivered into plant cells suppress plant immune responses and modulate host metabolism to support the infection processes of pathogens. Reactive oxygen species (ROS act as cellular signaling molecules to trigger plant immune responses, such as pathogen-associated molecular pattern (PAMP-triggered immunity (PTI and effector-triggered immunity. In this review, we discuss recent insights into the molecular functions of pathogen effectors that target multiple steps in the ROS signaling pathway in plants. The perception of PAMPs by pattern recognition receptors leads to the rapid and strong production of ROS through activation of NADPH oxidase Respiratory Burst Oxidase Homologs (RBOHs as well as peroxidases. Specific pathogen effectors directly or indirectly interact with plant nucleotide-binding leucine-rich repeat receptors to induce ROS production and the hypersensitive response in plant cells. By contrast, virulent pathogens possess effectors capable of suppressing plant ROS bursts in different ways during infection. PAMP-triggered ROS bursts are suppressed by pathogen effectors that target mitogen-activated protein kinase cascades. Moreover, pathogen effectors target vesicle trafficking or metabolic priming, leading to the suppression of ROS production. Secreted pathogen effectors block the metabolic coenzyme NADP-malic enzyme, inhibiting the transfer of electrons to the NADPH oxidases (RBOHs responsible for ROS generation. Collectively, pathogen effectors may have evolved to converge on a common host protein network to suppress the common plant immune system, including the ROS burst and cell death response in plants.

  11. Iron and Reactive Oxygen Species: Friends or Foes of Cancer Cells?

    Science.gov (United States)

    Bystrom, Laura M.

    2014-01-01

    Abstract Significance: In this review, the dual nature of both iron and reactive oxygen species (ROS) will be explored in normal and cancer cell metabolism. Although iron and ROS play important roles in cellular homeostasis, they may also contribute to carcinogenesis. On the other hand, many studies have indicated that abrogation of iron metabolism, elevation of ROS, or modification of redox regulatory mechanisms in cancer cells, should be considered as therapeutic approaches for cancer. Recent Advances: Drugs that target different aspects of iron metabolism may be promising therapeutics for cancer. The ability of iron chelators to cause iron depletion and/or elevate ROS levels indicates that these types of compounds have more potential as antitumor medicines than originally expected. Other natural and synthetic compounds that target pathways involved in ROS homeostasis also have potential value alone or in combination with current chemotherapeutics. Critical Issues: Although ROS induction and iron depletion may be targets for cancer therapies, the optimal therapeutic strategies have yet to be identified. This review highlights some of the research that strives to identify such therapeutics. Future Directions: More studies are needed to better understand the role of iron and ROS in carcinogenesis not only as cancer promoters, but also as cytotoxic agents to cancer cells and cancer stem cells (CSCs). Moreover, the structure–activity effects of iron chelators and other compounds that increase ROS and/or disrupt iron metabolism need to be further evaluated to assess the effectiveness and selectivity of these compounds against both cancer and CSCs. Antioxid. Redox Signal. 20, 1917–1924. PMID:23198911

  12. Reactive oxygen species mediate TNFR1 increase after TRPV1 activation in mouse DRG neurons

    Directory of Open Access Journals (Sweden)

    Westlund Karin N

    2009-06-01

    Full Text Available Abstract Background Transient receptor potential vanilloid subtype 1 (TRPV1 is activated by low pH/protons and is well known to be involved in hyperalgesia during inflammation. Tumor necrosis factor α (TNF-α, a proinflammatory cytokine, is involved in nociceptive responses causing hyperalgesia through TNF receptor type 1 (TNFR1 activation. Reactive oxygen species (ROS production is also prominently increased in inflamed tissue. The present study investigated TNFR1 receptors in primary cultured mouse dorsal root ganglion (DRG neurons after TRPV1 activation and the involvement of ROS. C57BL/6 mice, both TRPV1 knockout and wild type, were used for immunofluorescent and live cell imaging. The L4 and L5 DRGs were dissected bilaterally and cultured overnight. TRPV1 was stimulated with capsaicin or its potent analog, resiniferatoxin. ROS production was measured with live cell imaging and TNFR1 was detected with immunofluorescence in DRG primary cultures. The TRPV1 knockout mice, TRPV1 antagonist, capsazepine, and ROS scavenger, N-tert-Butyl-α-phenylnitrone (PBN, were employed to explore the functional relationship among TRPV1, ROS and TNFR1 in these studies. Results The results demonstrate that TRPV1 activation increases TNFR1 receptors and ROS generation in primary cultures of mouse DRG neurons. Activated increases in TNFR1 receptors and ROS production are absent in TRPV1 deficient mice. The PBN blocks increases in TNFR1 and ROS production induced by capsaicin/resiniferatoxin. Conclusion TRPV1 activation increases TNFR1 in cultured mouse DRG neurons through a ROS signaling pathway, a novel sensitization mechanism in DRG neurons.

  13. Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming

    Science.gov (United States)

    Paital, Biswaranjan; Panda, Sumana Kumari; Hati, Akshaya Kumar; Mohanty, Bobllina; Mohapatra, Manoj Kumar; Kanungo, Shyama; Chainy, Gagan Bihari Nityananda

    2016-01-01

    The world is projected to experience an approximate doubling of atmospheric CO2 concentration in the next decades. Rise in atmospheric CO2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 °C-5.8 °C by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species (ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress (OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to

  14. PKCα promotes generation of reactive oxygen species via DUOX2 in hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiajun; Shao, Miaomiao; Liu, Min; Peng, Peike; Li, Lili; Wu, Weicheng; Wang, Lan [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, 200032 Shanghai (China); Duan, Fangfang [Institute of Biomedical Science, Fudan University, Shanghai (China); Zhang, Mingming; Song, Shushu [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, 200032 Shanghai (China); Jia, Dongwei, E-mail: jiadongwei@fudan.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, 200032 Shanghai (China); Ruan, Yuanyuan, E-mail: yuanyuanruan@fudan.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, 200032 Shanghai (China); Gu, Jianxin [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, 200032 Shanghai (China); Institute of Biomedical Science, Fudan University, Shanghai (China)

    2015-08-07

    Hepatocellular carcinoma (HCC) remains the second leading cause of cancer-related death worldwide, and elevated rates of reactive oxygen species (ROS) have long been considered as a hallmark of almost all types of cancer including HCC. Protein kinase C alpha (PKCα), a serine/threonine kinase among conventional PKC family, is recognized as a major player in signal transduction and tumor progression. Overexpression of PKCα is commonly observed in human HCC and associated with its poor prognosis. However, how PKCα is involved in hepatocellular carcinogenesis remains not fully understood. In this study, we found that among the members of conventional PKC family, PKCα, but not PKCβI or βII, promoted ROS production in HCC cells. PKCα stimulated generation of ROS by up-regulating DUOX2 at post-transcriptional level. Depletion of DUOX2 abrogated PKCα-induced activation of AKT/MAPK pathways as well as cell proliferation, migration and invasion in HCC cells. Moreover, the expression of DUOX2 and PKCα was well positively correlated in both HCC cell lines and patient samples. Collectively, our findings demonstrate that PKCα plays a critical role in HCC development by inducing DUOX2 expression and ROS generation, and propose a strategy to target PKCα/DUOX2 as a potential adjuvant therapy for HCC treatment. - Highlights: • PKCα promotes the generation of ROS in hepatocellular carcinoma. • PKCα induces ROS production by up-regulating DUOX2 at post-transcriptional level. • DUOX2 is required for PKCα-induced AKT/MAPK activation and tumor progression in HCC. • The expression of PKCα is positively correlated with DUOX2 in HCC.

  15. Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming.

    Science.gov (United States)

    Paital, Biswaranjan; Panda, Sumana Kumari; Hati, Akshaya Kumar; Mohanty, Bobllina; Mohapatra, Manoj Kumar; Kanungo, Shyama; Chainy, Gagan Bihari Nityananda

    2016-02-26

    The world is projected to experience an approximate doubling of atmospheric CO2 concentration in the next decades. Rise in atmospheric CO2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 °C-5.8 °C by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species (ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress (OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to

  16. AMPK signaling in skeletal muscle during exercise: Role of reactive oxygen and nitrogen species.

    Science.gov (United States)

    Morales-Alamo, David; Calbet, Jose A L

    2016-09-01

    Reactive oxygen and nitrogen species (RONS) are generated during exercise depending on intensity, duration and training status. A greater amount of RONS is released during repeated high-intensity sprint exercise and when the exercise is performed in hypoxia. By activating adenosine monophosphate-activated kinase (AMPK), RONS play a critical role in the regulation of muscle metabolism but also in the adaptive responses to exercise training. RONS may activate AMPK by direct an indirect mechanisms. Directly, RONS may activate or deactivate AMPK by modifying RONS-sensitive residues of the AMPK-α subunit. Indirectly, RONS may activate AMPK by reducing mitochondrial ATP synthesis, leading to an increased AMP:ATP ratio and subsequent Thr(172)-AMPK phosphorylation by the two main AMPK kinases: LKB1 and CaMKKβ. In presence of RONS the rate of Thr(172)-AMPK dephosphorylation is reduced. RONS may activate LKB1 through Sestrin2 and SIRT1 (NAD(+)/NADH.H(+)-dependent deacetylase). RONS may also activate CaMKKβ by direct modification of RONS sensitive motifs and, indirectly, by activating the ryanodine receptor (Ryr) to release Ca(2+). Both too high (hypoxia) and too low (ingestion of antioxidants) RONS levels may lead to Ser(485)-AMPKα1/Ser(491)-AMPKα2 phosphorylation causing inhibition of Thr(172)-AMPKα phosphorylation. Exercise training increases muscle antioxidant capacity. When the same high-intensity training is applied to arm and leg muscles, arm muscles show signs of increased oxidative stress and reduced mitochondrial biogenesis, which may be explained by differences in RONS-sensing mechanisms and basal antioxidant capacities between arm and leg muscles. Efficient adaptation to exercise training requires optimal exposure to pulses of RONS. Inappropriate training stimulus may lead to excessive RONS formation, oxidative inactivation of AMPK and reduced adaptation or even maladaptation. Theoretically, exercise programs should be designed taking into account the

  17. Detection and Characterization of Reactive Oxygen and Nitrogen Species in Biological Systems by Monitoring Species-Specific Products.

    Science.gov (United States)

    Hardy, Micael; Zielonka, Jacek; Karoui, Hakim; Sikora, Adam; Michalski, Radosław; Podsiadły, Radosław; Lopez, Marcos; Vasquez-Vivar, Jeannette; Kalyanaraman, Balaraman; Ouari, Olivier

    2018-05-20

    Since the discovery of the superoxide dismutase enzyme, the generation and fate of short-lived oxidizing, nitrosating, nitrating, and halogenating species in biological systems has been of great interest. Despite the significance of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in numerous diseases and intracellular signaling, the rigorous detection of ROS and RNS has remained a challenge. Recent Advances: Chemical characterization of the reactions of selected ROS and RNS with electron paramagnetic resonance (EPR) spin traps and fluorescent probes led to the establishment of species-specific products, which can be used for specific detection of several forms of ROS and RNS in cell-free systems and in cultured cells in vitro and in animals in vivo. Profiling oxidation products from the ROS and RNS probes provides a rigorous method for detection of those species in biological systems. Formation and detection of species-specific products from the probes enables accurate characterization of the oxidative environment in cells. Measurement of the total signal (fluorescence, chemiluminescence, etc.) intensity does not allow for identification of the ROS/RNS formed. It is critical to identify the products formed by using chromatographic or other rigorous techniques. Product analyses should be accompanied by monitoring of the intracellular probe level, another factor controlling the yield of the product(s) formed. More work is required to characterize the chemical reactivity of the ROS/RNS probes, and to develop new probes/detection approaches enabling real-time, selective monitoring of the specific products formed from the probes. Antioxid. Redox Signal. 28, 1416-1432.

  18. The characterisation of vapour-phase alkali metal-tellurium-oxygen species

    International Nuclear Information System (INIS)

    Gomme, R.A.; Ogden, J.S.; Bowsher, B.R.

    1986-10-01

    Detailed assessments of hypothetical severe accidents in light water reactors require the identification of the chemical forms of the radionuclides in order to determine their transport characteristics. Caesium and tellurium are important volatile fission products in accident scenarios. This report describes detailed studies to characterise the chemical species that vaporise from heated mixtures of various alkali metal-tellurium-oxygen systems. The molecular species were characterised by a combination of quadrupole mass spectrometry and matrix isolation-infrared spectroscopy undertaken in conjunction with experiments involving oxygen-18 substitution. The resulting spectra were interpreted in terms of a vapour-phase molecule with the stoichiometry M 2 TeO 3 (M = K,Rb,Cs) for M/Te molecular ratios of ∼ 2, and polymeric species for ratios < 2. This work has demonstrated the stability of caesium tellurite. The formation of this relatively low-volatility, water-soluble species could significantly modify the transport and release of caesium and tellurium. The data presented in this report should allow more comprehensive thermodynamic calculations to be undertaken that assist in the quantification of fission product behaviour during severe reactor accidents. (author)

  19. The role of reactive oxygen species in near-ultraviolet (320-400 nm) light inactivation of Escherichia coli

    International Nuclear Information System (INIS)

    Sammartano, L.J.

    1988-01-01

    The purpose of the present study was to further elucidate the mechanism of near-UV inactivation in Escherichia coli. Several genetic and biochemical techniques were employed to examine the role of oxygen reactive species in near-UV mediated damage to DNA and membrane components, and to identify endogenous photosensitizers. The results demonstrate that the near-UV inactivation process is initiated when the radiant energy is absorbed by components of the respiratory chain, including cytochromes. The absorption of energy causes the chromophore to be electronically excited into the triplet state which leads to subsequent generation of oxygen reactive species within the membrane. The first line of cellular defense against this oxidative stress is a complex network of antioxidants and scavengers, including catalase, superoxide dismutase and glutathione reductase. E. coli cells also have a second line of defense that incorporates repair systems. In this study evidence is provided for an excision repair pathway that is unique to near-UV mediated damage. Results suggest that a unique, but as yet unidentified, DNA lesion occurs in near-UV irradiated cells. Evidence is also presented that shows near-UV mediated damage also occurs in the membrane

  20. Exposure of Bacterial Biofilms to Electrical Current Leads to Cell Death Mediated in Part by Reactive Oxygen Species.

    Science.gov (United States)

    Brinkman, Cassandra L; Schmidt-Malan, Suzannah M; Karau, Melissa J; Greenwood-Quaintance, Kerryl; Hassett, Daniel J; Mandrekar, Jayawant N; Patel, Robin

    2016-01-01

    Bacterial biofilms may form on indwelling medical devices such as prosthetic joints, heart valves and catheters, causing challenging-to-treat infections. We have previously described the 'electricidal effect', in which bacterial biofilms are decreased following exposure to direct electrical current. Herein, we sought to determine if the decreased bacterial quantities are due to detachment of biofilms or cell death and to investigate the role that reactive oxygen species (ROS) play in the observed effect. Using confocal and electron microscopy and flow cytometry, we found that direct current (DC) leads to cell death and changes in the architecture of biofilms formed by Gram-positive and Gram-negative bacteria. Reactive oxygen species (ROS) appear to play a role in DC-associated cell death, as there was an increase in ROS-production by Staphylococcus aureus and Staphylococcus epidermidis biofilms following exposure to DC. An increase in the production of ROS response enzymes catalase and superoxide dismutase (SOD) was observed for S. aureus, S. epidermidis and Pseudomonas aeruginosa biofilms following exposure to DC. Additionally, biofilms were protected from cell death when supplemented with antioxidants and oxidant scavengers, including catalase, mannitol and Tempol. Knocking out SOD (sodAB) in P. aeruginosa led to an enhanced DC effect. Microarray analysis of P. aeruginosa PAO1 showed transcriptional changes in genes related to the stress response and cell death. In conclusion, the electricidal effect results in death of bacteria in biofilms, mediated, at least in part, by production of ROS.

  1. Hydrous Ferric Oxides in Sediment Catalyze Formation of Reactive Oxygen Species during Sulfide Oxidation

    Directory of Open Access Journals (Sweden)

    Sarah A. Murphy

    2016-11-01

    Full Text Available Abstract: This article describes the formation of reactive oxygen species as a result of the oxidation of dissolved sulfide by Fe(III-containing sediments suspended in oxygenated seawater over the pH range 7.00 and 8.25. Sediment samples were obtained from across the coastal littoral zone in South Carolina, US, at locations from the beach edge to the forested edge of a Spartina dominated estuarine salt marsh and suspended in aerated seawater. Reactive oxygen species (superoxide and hydrogen peroxide production was initiated in sediment suspensions by the addition of sodium bisulfide. The subsequent loss of HS-, formation of Fe(II (as indicated by Ferrozine, and superoxide and hydrogen peroxide were monitored over time. The concentration of superoxide rose from the baseline and then persisted at an apparent steady state concentration of approximately 500 nanomolar at pH 8.25 and 200 nanomolar at pH 7.00 respectively until >97% hydrogen sulfide was consumed. Measured superoxide was used to predict hydrogen peroxide yield based on superoxide dismutation. Dismutation alone quantitatively predicted hydrogen peroxide formation at pH 8.25 but over predicted hydrogen peroxide formation at pH 7 by a factor of approximately 102. Experiments conducted with episodic spikes of added hydrogen peroxide indicated rapid hydrogen peroxide consumption could account for its apparent low instantaneous yield, presumably the result of its reaction with Fe(II species, polysulfides or bisulfite. All sediment samples were characterized for total Fe, Cu, Mn, Ni, Co and hydrous ferric oxide by acid extraction followed by mass spectrometric or spectroscopic characterization. Sediments with the highest loadings of hydrous ferric oxide were the only sediments that produced significant dissolved Fe(II species or ROS as a result of sulfide exposure.

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

    Science.gov (United States)

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

    2011-06-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chibli, H.; Carlini, L.; Park, S.; Dimitrijevic, N. M.; Nadeau, J. L. (Center for Nanoscale Materials); ( CSE); (McGill Univ.)

    2011-01-01

    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.

  4. The antioxidant action of Polypodium leucotomos extract and kojic acid: reactions with reactive oxygen species

    Directory of Open Access Journals (Sweden)

    A.J. Gomes

    2001-11-01

    Full Text Available Two natural products Polypodium leucotomos extract (PL and kojic acid (KA were tested for their ability to scavenge reactive oxygen species (·OH, ·O2-, H2O2, ¹O2 in phosphate buffer. Hydroxyl radicals were generated by the Fenton reaction, and the rate constants of scavenging were 1.6 x 10(9 M-1 s-1 for KA and 1.0 x 10(9 M-1 s-1 for PL, similar to that of ethanol (1.4 x 10(9 M-1 s-1. With superoxide anions generated by the xanthine/hypoxanthine system, KA and PL (0.2-1.0 mg/ml inhibited ·O2-dependent reduction of nitroblue tetrazolium by up to 30 and 31%, respectively. In the detection of ¹O2 by rose bengal irradiation, PL at 1.0 mg/ml quenched singlet oxygen by 43% relative to azide and KA by 36%. The present study demonstrates that PL showed an antioxidant effect, scavenging three of four reactive oxygen species tested here. Unlike KA, PL did not significantly scavenge hydrogen peroxide.

  5. Reactive oxygen species: role in the development of cancer and various chronic conditions

    Directory of Open Access Journals (Sweden)

    Waris Gulam

    2006-05-01

    Full Text Available Abstract Oxygen derived species such as superoxide radical, hydrogen peroxide, singlet oxygen and hydroxyl radical are well known to be cytotoxic and have been implicated in the etiology of a wide array of human diseases, including cancer. Various carcinogens may also partly exert their effect by generating reactive oxygen species (ROS during their metabolism. Oxidative damage to cellular DNA can lead to mutations and may, therefore, play an important role in the initiation and progression of multistage carcinogenesis. The changes in DNA such as base modification, rearrangement of DNA sequence, miscoding of DNA lesion, gene duplication and the activation of oncogenes may be involved in the initiation of various cancers. Elevated levels of ROS and down regulation of ROS scavengers and antioxidant enzymes are associated with various human diseases including various cancers. ROS are also implicated in diabtes and neurodegenerative diseases. ROS influences central cellular processes such as proliferation a, apoptosis, senescence which are implicated in the development of cancer. Understanding the role of ROS as key mediators in signaling cascades may provide various opportunities for pharmacological intervention.

  6. Reactive oxygen species explicit dosimetry (ROSED) of a type 1 photosensitizer

    Science.gov (United States)

    Ong, Yi Hong; Kim, Michele M.; Huang, Zheng; Zhu, Timothy C.

    2018-02-01

    Type I photodynamic therapy (PDT) is based on the use of photochemical reactions mediated through an interaction between a tumor-selective photosensitizer, photoexcitation with a specific wavelength of light, and production of reactive oxygen species (ROS). The goal of this study is to develop a model to calculate reactive oxygen species concentration ([ROS]rx) after Tookad®-mediated vascular PDT. Mice with radiation-induced fibrosarcoma (RIF) tumors were treated with different light fluence and fluence rate conditions. Explicit measurements of photosensitizer drug concentration were made via diffuse reflective absorption spectrum using a contact probe before and after PDT. Blood flow and tissue oxygen concentration over time were measured during PDT as a mean to validate the photochemical parameters for the ROSED calculation. Cure index was computed from the rate of tumor regrowth after treatment and was compared against three calculated dose metrics: total light fluence, PDT dose, reacted [ROS]rx. The tumor growth study demonstrates that [ROS]rx serves as a better dosimetric quantity for predicting treatment outcome, as a clinically relevant tumor growth endpoint.

  7. A comparative kinetic and mechanistic study between tetrahydrozoline and naphazoline toward photogenerated reactive oxygen species.

    Science.gov (United States)

    Criado, Susana; García, Norman A

    2010-01-01

    Kinetic and mechanistic aspects of the vitamin B2 (riboflavin [Rf])-sensitized photo-oxidation of the imidazoline derivates (IDs) naphazoline (NPZ) and tetrahydrozoline (THZ) were investigated in aqueous solution. The process appears as important on biomedical grounds, considering that the vitamin is endogenously present in humans, and IDs are active components of ocular medicaments of topical application. Under aerobic visible light irradiation, a complex picture of competitive interactions between sensitizer, substrates and dissolved oxygen takes place: the singlet and triplet ((3)Rf*) excited states of Rf are quenched by the IDs: with IDs concentrations ca. 5.0 mM and 0.02 mM Rf, (3)Rf* is quenched by IDs, in a competitive fashion with dissolved ground state oxygen. Additionally, the reactive oxygen species: O(2)((1)Delta(g)), O(2)(*-), HO(*) and H(2)O(2), generated from (3)Rf* and Rf(*-), were detected with the employment of time-resolved methods or specific scavengers. Oxygen uptake experiments indicate that, for NPZ, only H(2)O(2) was involved in the photo-oxidation. In the case of THZ, O(2)(*-), HO(*) and H(2)O(2) were detected, whereas only HO(*) was unambiguously identified as THZ oxidative agents. Upon direct UV light irradiation NPZ and THZ generate O(2)((1)Delta(g)), with quantum yields of 0.2 (literature value, employed as a reference) and 0.08, respectively, in acetonitrile.

  8. Photofunctional Co-Cr Alloy Generating Reactive Oxygen Species for Photodynamic Applications

    Directory of Open Access Journals (Sweden)

    Kang-Kyun Wang

    2013-01-01

    Full Text Available We report the fabrication of photofunctional Co-Cr alloy plate that is prepared by a simple modification process for photodynamic application. Photoinduced functionality is provided by the photosensitizer of hematoporphyrin (Hp that initially generates reactive oxygen species (ROS such as superoxide anion radical and singlet oxygen. The photosensitizer with carboxyl group was chemically bonded to the surface of the Co-Cr alloy plate by esterification reaction. Microstructure and elemental composition of the Co-Cr alloy plate were checked with scanning electron microscopy (SEM and energy dispersive X-ray spectrometer (EDS. Fabrication of the photofunctionality of the Co-Cr alloy plate was confirmed with X-ray photoelectron spectroscopy (XPS, reflectance UV-Vis absorption, and emission spectroscopy. Reactive oxygen generation from the photofunctional Co-Cr alloy plate was confirmed by using the decomposition reaction of 1,3-diphenylisobenzofuran (DPBF. The results suggest that the immobilized photosensitizer molecules on the surface of Co-Cr alloy plate still possess their optical and functional properties including reactive oxygen generation. To open the possibility for its application as a photodynamic material to biological system, the fabricated photofunctional Co-Cr alloy is applied to the decomposition of smooth muscle cells.

  9. Heavy-metal-induced reactive oxygen species: phytotoxicity and physicochemical changes in plants.

    Science.gov (United States)

    Shahid, Muhammad; Pourrut, Bertrand; Dumat, Camille; Nadeem, Muhammad; Aslam, Muhammad; Pinelli, Eric

    2014-01-01

    As a result of the industrial revolution, anthropogenic activities have enhanced there distribution of many toxic heavy metals from the earth's crust to different environmental compartments. Environmental pollution by toxic heavy metals is increasing worldwide, and poses a rising threat to both the environment and to human health.Plants are exposed to heavy metals from various sources: mining and refining of ores, fertilizer and pesticide applications, battery chemicals, disposal of solid wastes(including sewage sludge), irrigation with wastewater, vehicular exhaust emissions and adjacent industrial activity.Heavy metals induce various morphological, physiological, and biochemical dysfunctions in plants, either directly or indirectly, and cause various damaging effects. The most frequently documented and earliest consequence of heavy metal toxicity in plants cells is the overproduction of ROS. Unlike redox-active metals such as iron and copper, heavy metals (e.g, Pb, Cd, Ni, AI, Mn and Zn) cannot generate ROS directly by participating in biological redox reactions such as Haber Weiss/Fenton reactions. However, these metals induce ROS generation via different indirect mechanisms, such as stimulating the activity of NADPH oxidases, displacing essential cations from specific binding sites of enzymes and inhibiting enzymatic activities from their affinity for -SH groups on the enzyme.Under normal conditions, ROS play several essential roles in regulating the expression of different genes. Reactive oxygen species control numerous processes like the cell cycle, plant growth, abiotic stress responses, systemic signalling, programmed cell death, pathogen defence and development. Enhanced generation of these species from heavy metal toxicity deteriorates the intrinsic antioxidant defense system of cells, and causes oxidative stress. Cells with oxidative stress display various chemical,biological and physiological toxic symptoms as a result of the interaction between ROS and

  10. Extracorporeal membrane oxygenation causes loss of intestinal epithelial barrier in the newborn piglet.

    Science.gov (United States)

    Kurundkar, Ashish R; Killingsworth, Cheryl R; McIlwain, R Britt; Timpa, Joseph G; Hartman, Yolanda E; He, Dongning; Karnatak, Rajendra K; Neel, Mary L; Clancy, John P; Anantharamaiah, G M; Maheshwari, Akhil

    2010-08-01

    Extracorporeal membrane oxygenation (ECMO) is an important life-support system used in neonates and young children with intractable cardiorespiratory failure. In this study, we used our porcine neonatal model of venoarterial ECMO to investigate whether ECMO causes gut barrier dysfunction. We subjected 3-wk-old previously healthy piglets to venoarterial ECMO for up to 8 h and evaluated gut mucosal permeability, bacterial translocation, plasma levels of bacterial products, and ultrastructural changes in gut epithelium. We also measured plasma lipopolysaccharide (LPS) levels in a small cohort of human neonates receiving ECMO. In our porcine model, ECMO caused a rapid increase in gut mucosal permeability within the first 2 h of treatment, leading to a 6- to 10-fold rise in circulating bacterial products. These changes in barrier function were associated with cytoskeletal condensation in epithelial cells, which was explained by phosphorylation of a myosin II regulatory light chain. In support of these findings, we also detected elevated plasma LPS levels in human neonates receiving ECMO, indicating a similar loss of gut barrier function in these infants. On the basis of these data, we conclude that ECMO is an independent cause of gut barrier dysfunction and bacterial translocation may be an important contributor to ECMO-related inflammation.

  11. Loss in species caused by tropical deforestation and their recovery through management

    Science.gov (United States)

    Ariel E. Lugo; John A. Parrotta; Sandra Brown

    1993-01-01

    The loss of species as a result of deforestation and degradation of tropical forest lands is widely discussed. Models based on island biogeography theory are used to evaluate the relationship between extinctions of species and deforestation. The analysis shows that natural resiliency causes the models to overestimate the rates of species extinctions for given...

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

    International Nuclear Information System (INIS)

    Popolan, Denisia M.; Bernhardt, Thorsten M.

    2011-01-01

    The oxidation of carbon monoxide with nitrous oxide on mass-selected Au 3 + and Ag 3 + 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 3 + the cluster itself acts as reactive species that facilitates the formation of CO 2 from N 2 O and CO, for silver the oxidized clusters Ag 3 O x + (n= 1-3) are identified as active in the CO oxidation reaction. Thus, in the case of the silver cluster cations N 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.

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

    Science.gov (United States)

    Popolan, Denisia M.; Bernhardt, Thorsten M.

    2011-03-01

    The oxidation of carbon monoxide with nitrous oxide on mass-selected Au3+ and Ag3+ 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 Au3+ the cluster itself acts as reactive species that facilitates the formation of CO2 from N2O and CO, for silver the oxidized clusters Ag3Ox+ (n = 1-3) are identified as active in the CO oxidation reaction. Thus, in the case of the silver cluster cations N2O 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.

  14. Developing Master Keys to Brain Pathology, Cancer and Aging from the Structural Biology of Proteins Controlling Reactive Oxygen Species and DNA Repair

    Science.gov (United States)

    Perry, J. Jefferson P.; Fan, Li; Tainer, John A.

    2007-01-01

    This review is focused on proteins with key roles in pathways controlling either reactive oxygen species or DNA damage responses, both of which are essential for preserving the nervous system. An imbalance of reactive oxygen species or inappropriate DNA damage response likely causes mutational or cytotoxic outcomes, which may lead to cancer and/or aging phenotypes. Moreover, individuals with hereditary disorders in proteins of these cellular pathways have significant neurological abnormalities. Mutations in a superoxide dismutase, which removes oxygen free radicals, may cause the neurodegenerative disease amyotrophic lateral sclerosis. Additionally, DNA repair disorders that affect the brain to varying extents include ataxia-telangiectasia-like disorder, Cockayne syndrome or Werner syndrome. Here, we highlight recent advances gained through structural biochemistry studies on enzymes linked to these disorders and other related enzymes acting within the same cellular pathways. We describe the current understanding of how these vital proteins coordinate chemical steps and integrate cellular signaling and response events. Significantly, these structural studies may provide a set of master keys to developing a unified understanding of the survival mechanisms utilized after insults by reactive oxygen species and genotoxic agents, and also provide a basis for developing an informed intervention in brain tumor and neurodegenerative disease progression. PMID:17174478

  15. MINIMAL ROLE FOR REACTIVE OXYGEN SPECIES IN DICHLOROACETIC ACID-INDUCED DYSMORPHOLOGY IN MOUSE WHOLE EMBRYO CULTURE.

    Science.gov (United States)

    Administration of dichloroacetate (DCA) to pregnant rats produces craniofacial, heart and other defects in their offspring. Exposure of zebrafish to DCA induces malformations and increases superoxide and nitric oxide production suggesting that reactive oxygen species (ROS) are as...

  16. Thiazolidinone prodrugs activated by reactive oxygen species for use in the treatment of inflammatory diseases and cancer

    DEFF Research Database (Denmark)

    2018-01-01

    Prodrugs activated predominantly or exclusively in inflammatory tissue, more particularly prodrugs of methotrexate and derivatives thereof, which are selectively activated by Reactive Oxygen Species (ROS) in inflammatory tissues associated with cancer and inflammatory diseases, as well as method...

  17. Phenol by direct hydroxylation of benzene with nitrous oxide - role of surface oxygen species in the reaction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Reitzmann, A.; Klemm, E.; Emig, G. [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Technische Chemie 1; Buchholz, S.A.; Zanthoff, H.W. [Bochum Univ. (Germany). Inst. of Technical Chemistry

    1998-12-31

    Transient experiments in a Temporal Analysis of Products (TAP) Reactor were performed to elucidate the role of surface oyxgen species in the oxidation of benzene to phenol on ZSM-5 type zeolites with nitrous oxide as a selective oxidant. It was shown by puls experiments with nitrous oxide that the mean lifetime of the generated surface oxygen species is between 0.2s at 500 C and about 4.2 s at 400 C. Afterwards the surface oxygen species desorb as molecular oxygen into the gas phase where total oxidation will take place if hydrocarbons are present. Dual puls experiments consisting of a nitrous oxide puls followed by a benzene puls allowed studying the reactivity of the surface oxygen species formed during the first puls. The observation of the phenol formation was impeded due to the strong sorption of phenol. Multipulse experiments were necessary to reach a pseudo steady state phenol yield. (orig.)

  18. The determination and analysis of site-specific rates of mitochondrial reactive oxygen species production

    DEFF Research Database (Denmark)

    Quinlan, Casey L; Perevoschikova, Irina V; Goncalves, Renata L S

    2013-01-01

    Mitochondrial reactive oxygen species (ROS) are widely implicated in physiological and pathological pathways. We propose that it is critical to understand the specific sites of mitochondrial ROS production and their mechanisms of action. Mitochondria possess at least eight distinct sites of ROS...... production in the electron transport chain and matrix compartment. In this chapter, we describe the nature of the mitochondrial ROS-producing machinery and the relative capacities of each site. We provide detailed methods for the measurement of H2O2 release and the conditions under which maximal rates from...

  19. Redox state, reactive oxygen species and adaptive growth in colonial hydroids.

    Science.gov (United States)

    Blackstone, N W

    2001-06-01

    Colonial metazoans often encrust surfaces over which the food supply varies in time or space. In such an environment, adaptive colony development entails adjusting the timing and spacing of feeding structures and gastrovascular connections to correspond to this variable food supply. To investigate the possibility of such adaptive growth, within-colony differential feeding experiments were carried out using the hydroid Podocoryna carnea. Indeed, such colonies strongly exhibited adaptive growth, developing dense arrays of polyps (feeding structures) and gastrovascular connections in areas that were fed relative to areas that were starved, and this effect became more consistent over time. To investigate mechanisms of signaling between the food supply and colony development, measurements were taken of metabolic parameters that have been implicated in signal transduction in other systems, particularly redox state and levels of reactive oxygen species. Utilizing fluorescence microscopy of P. carnea cells in vivo, simultaneous measurements of redox state [using NAD(P)H] and hydrogen peroxide (using 2',7'-dichlorofluorescin diacetate) were taken. Both measures focused on polyp epitheliomuscular cells, since these exhibit the greatest metabolic activity. Colonies 3-5h after feeding were relatively oxidized, with low levels of peroxide, while colonies 24h after feeding were relatively reduced, with high levels of peroxide. The functional role of polyps in feeding and generating gastrovascular flow probably produced this dichotomy. Polyps 3-5h after feeding contract maximally, and this metabolic demand probably shifts the redox state in the direction of oxidation and diminishes levels of reactive oxygen species. In contrast, 24h after feeding, polyps are quiescent, and this lack of metabolic demand probably shifts the redox state in the direction of reduction and increases levels of reactive oxygen species. Within-colony differential feeding experiments were carried out on

  20. Impact of reactive oxygen species on antioxidant capacity of male reproductive system.

    Science.gov (United States)

    Riaz, Muhammad; Mahmood, Zahed; Shahid, Muhammad; Saeed, M Usman Qamar; Tahir, Imtiaz Mahmood; Shah, Sm Ali; Munir, Naveed; El-Ghorab, Ahmed

    2016-09-01

    The present research work was aimed to study the mutual interaction of reactive oxygen species (ROS) and basal cells antioxidant capacity in the male reproductive system and to further establish the association between selected heavy metals and stress markers. Total oxidant status (TOS) and total antioxidant status (TAS) of serum and seminal plasma were determined by automated photometric methods. The concentrations of Selenium (Se), Lead (Pb), and Cadmium (Cd) were determined by using atomic absorption spectrophotometer. The TOS was increased significantly (P male infertility. © The Author(s) 2015.

  1. Reactive oxygen species modulator 1, a novel protein, combined with carcinoembryonic antigen in differentiating malignant from benign pleural effusion.

    Science.gov (United States)

    Chen, Xianmeng; Zhang, Na; Dong, Jiahui; Sun, Gengyun

    2017-05-01

    The differential diagnosis of malignant pleural effusion and benign pleural effusion remains a clinical problem. Reactive oxygen species modulator 1 is a novel protein overexpressed in various human tumors. The objective of this study was to evaluate the diagnostic value of joint detection of reactive oxygen species modulator 1 and carcinoembryonic antigen in the differential diagnosis of malignant pleural effusion and benign pleural effusion. One hundred two consecutive patients with pleural effusion (including 52 malignant pleural effusion and 50 benign pleural effusion) were registered in this study. Levels of reactive oxygen species modulator 1 and carcinoembryonic antigen were measured by enzyme-linked immunosorbent assay and radioimmunoassay, respectively. Results showed that the concentrations of reactive oxygen species modulator 1 both in pleural fluid and serum of patients with malignant pleural effusion were significantly higher than those of benign pleural effusion (both p pleural fluid reactive oxygen species modulator 1 were 61.54% and 82.00%, respectively, with the optimized cutoff value of 589.70 pg/mL. However, the diagnostic sensitivity and specificity of serum reactive oxygen species modulator 1 were only 41.38% and 86.21%, respectively, with the cutoff value of 27.22 ng/mL, indicating that serum reactive oxygen species modulator 1 may not be a good option in the differential diagnosis of malignant pleural effusion and benign pleural effusion. The sensitivity and specificity of pleural fluid carcinoembryonic antigen were 69.23% and 88.00%, respectively, at the cutoff value of 3.05 ng/mL, while serum carcinoembryonic antigen were 80.77% and 72.00% at the cutoff value of 2.60 ng/mL. The sensitivity could be raised to 88.17% in parallel detection of plural fluid reactive oxygen species modulator 1 and carcinoembryonic antigen concentration, and the specificity could be improved to 97.84% in serial detection.

  2. Enhancement of the Acrolein-Induced Production of Reactive Oxygen Species and Lung Injury by GADD34

    Directory of Open Access Journals (Sweden)

    Yang Sun

    2015-01-01

    Full Text Available Chronic obstructive pulmonary disease (COPD is characterized by lung destruction and inflammation. As a major compound of cigarette smoke, acrolein plays a critical role in the induction of respiratory diseases. GADD34 is known as a growth arrest and DNA damage-related gene, which can be overexpressed in adverse environmental conditions. Here we investigated the effects of GADD34 on acrolein-induced lung injury. The intranasal exposure of acrolein induced the expression of GADD34, developing the pulmonary damage with inflammation and increase of reactive oxygen species (ROS. Conversely, the integrality of pulmonary structure was preserved and the generation of ROS was reduced in GADD34-knockout mice. Acrolein-induced phosphorylation of eIF2α in GADD34-knockout epithelial cells by shRNA protected cell death by reducing misfolded protein-caused oxidative stress. These data indicate that GADD34 participates in the development of acrolein-induced lung injury.

  3. Enhancement of the acrolein-induced production of reactive oxygen species and lung injury by GADD34.

    Science.gov (United States)

    Sun, Yang; Ito, Sachiko; Nishio, Naomi; Tanaka, Yuriko; Chen, Nana; Liu, Lintao; Isobe, Ken-ichi

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) is characterized by lung destruction and inflammation. As a major compound of cigarette smoke, acrolein plays a critical role in the induction of respiratory diseases. GADD34 is known as a growth arrest and DNA damage-related gene, which can be overexpressed in adverse environmental conditions. Here we investigated the effects of GADD34 on acrolein-induced lung injury. The intranasal exposure of acrolein induced the expression of GADD34, developing the pulmonary damage with inflammation and increase of reactive oxygen species (ROS). Conversely, the integrality of pulmonary structure was preserved and the generation of ROS was reduced in GADD34-knockout mice. Acrolein-induced phosphorylation of eIF2α in GADD34-knockout epithelial cells by shRNA protected cell death by reducing misfolded protein-caused oxidative stress. These data indicate that GADD34 participates in the development of acrolein-induced lung injury.

  4. PVP-coated silver nanoparticles and silver ions induce reactive oxygen species, apoptosis and necrosis in THP-1 monocytes

    DEFF Research Database (Denmark)

    Foldbjerg, Rasmus; Olesen, Ping Liu; Hougaard, Mads

    2009-01-01

    , both Ag NPs and Ag+ were shown to induce apoptosis and necrosis in THP-1 cells depending on dose and exposure time. Furthermore, the presence of apoptosis could be confirmed by the TUNEL method. A number of studies have implicated the production of reactive oxygen species (ROS) in cytotoxicity mediated...... the effect of well characterized, PVP-coated Ag NPs (69 nm ± 3 nm) and Ag+ in a human monocytic cell line (THP-1). Characterization of the Ag NPs was conducted in both stock suspension and cell media with or without serum and antibiotics. By using the flowcytometric annexin V/propidium iodide (PI) assay...... by NPs. We used the fluorogenic probe, 2′,7′-dichlorofluorescein to assess the levels of intracellular ROS during exposure to Ag NPs and Ag+. A drastic increase in ROS levels could be detected after 6–24 h suggesting that oxidative stress is an important mediator of cytotoxicity caused by Ag NPs and Ag+....

  5. Enhancement of the Acrolein-Induced Production of Reactive Oxygen Species and Lung Injury by GADD34

    Science.gov (United States)

    Sun, Yang; Ito, Sachiko; Nishio, Naomi; Tanaka, Yuriko; Chen, Nana; Isobe, Ken-ichi

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) is characterized by lung destruction and inflammation. As a major compound of cigarette smoke, acrolein plays a critical role in the induction of respiratory diseases. GADD34 is known as a growth arrest and DNA damage-related gene, which can be overexpressed in adverse environmental conditions. Here we investigated the effects of GADD34 on acrolein-induced lung injury. The intranasal exposure of acrolein induced the expression of GADD34, developing the pulmonary damage with inflammation and increase of reactive oxygen species (ROS). Conversely, the integrality of pulmonary structure was preserved and the generation of ROS was reduced in GADD34-knockout mice. Acrolein-induced phosphorylation of eIF2α in GADD34-knockout epithelial cells by shRNA protected cell death by reducing misfolded protein-caused oxidative stress. These data indicate that GADD34 participates in the development of acrolein-induced lung injury. PMID:25821552

  6. Production of reactive oxygen species during the aerobic and anaerobic exercise

    Directory of Open Access Journals (Sweden)

    Edilson Serpeloni Cyrino

    2006-06-01

    Full Text Available The protective effect of physical exercise against diseases is well established in literature, although it is known that exercising generates free radicals. Despite the mitochondria being the main source of free radicals, the processes of ischemia, inflammation, and reperfusion can also form free radicals. The purpose of this literature review was to investigate the impact of both aerobic and anaerobic physical exercise on the generation of reactive oxygen species (ROS. We verified that cellular and tissue damage by free radicals, caused by lipid peroxidation and inflammation, occurs in both types of physical exercises, especially in high intensity efforts. There are indications that ROS generation during physical exercise cannot be modulated by regular training, however, the cellular environment can increase antioxidant endogenous concentration to compensate for that stress. Moreover, ROS regulation can differently occur in aerobic and anaerobic exercises. Therefore, the control of oxidative stress may be very important, particularly, in anaerobic exercises. RESUMOO efeito protetor do exercício físico contra doenças está bem estabelecido na literatura, embora haja conhecimento de que sua prática gera radicais livres. Apesar de a mitocôndria ser a principal fonte de radicais livres, os processos de isquemia, inflamação e reperfusão também podem causar formação de radicais livres. Apartir de uma ampla revisão da literatura, o objetivo deste estudo foi investigar o impacto do exercício físico sob condições de aerobiose e anaerobiose sobre a geração de espécies reativas de oxigênio (ERO. Verificou-se que o dano celular e tecidual por radicais livres, causado por peroxidação lipídica e inflamação, ocorre em ambos os tipos de exercícios físicos, sobretudo em esforços de alta intensidade. Existem indicações de que a geração de ERO durante o exercício físico não pode ser modulada pelo treinamento regular, contudo, o

  7. Physalis angulata induces death of promastigotes and amastigotes of Leishmania (Leishmania) amazonensis via the generation of reactive oxygen species.

    Science.gov (United States)

    Da Silva, B J M; Da Silva, R R P; Rodrigues, A P D; Farias, L H S; Do Nascimento, J L M; Silva, E O

    2016-03-01

    Leishmaniasis are a neglected group of emerging diseases that have been found in 98 countries and are caused by protozoa of the genus Leishmania. The therapy for leishmaniasis causes several side effects and leads to drug-resistant strains. Natural products from plants have exhibited activities against Leishmania in various experimental models. Physalis angulata is a widely used plant in popular medicine, and in the literature it has well-documented leishmanicidal activity. However, its mechanism of action is still unknown. Thus, this study aims to evaluate the mechanism driving the leishmanicidal activity of an aqueous extract of P. angulata root (AEPa). AEPa was effective against both promastigotes and intracellular amastigote forms of Leishmania amazonensis. This effect was mediated by an increase of reactive oxygen species (ROS), but not of nitric oxide (NO). The increased production of ROS induces cell death by phenotypes seems by apoptosis cell death in Leishmania, but not autophagy or necrosis. In addition, morphological analysis of macrophages showed that AEPa induced a high number of cytoplasmic projections, increased the volume of cytoplasm and number of vacuoles, caused cytoskeleton alterations and resulted in high spreading ability. AEPa also promoted superoxide anion (O2(-)) production in both uninfected macrophages and those infected with Leishmania. Therefore, these results revealed that AEPa causes cell death by phenotypes seems by apoptosis cell death in L. amazonensis and modulates macrophage activation through morphofunctional alterations and O2(-) generation to induce Leishmania death. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Oxygen-containing coke species in zeolite-catalyzed conversion of methanol to hydrocarbons

    KAUST Repository

    Liu, Zhaohui

    2016-10-06

    Zeolites are the most commonly used catalysts for methanol-to-hydrocarbon (MTH) conversion. Here, we identified two oxygen-containing compounds as coke species in zeolite catalysts after MTH reactions. We investigated the possible influences of the oxygen-containing compounds on coke formation, catalyst deactivation, product selectivity, and the induction period of the MTH reaction through a series of controlled experiments in which one of the identified compounds (2,3-dimethyl-2-cyclopenten-1-one) was co-fed with methanol over a zeolite H-ZSM-5 catalyst. Our results allow us to infer that once produced, the oxygen-containing compounds block the Brønsted acid sites by strong chemisorption and their rapid conversion to aromatics expedites the formation of coke and thus the deactivation of the catalyst. A minor effect of the production of such compounds during the MTH reaction is that the aromatic-based catalytic cycle can be slightly promoted to give higher selectivity to ethylene.

  9. Reactive oxygen species production, induced by atmospheric modification, alter conidial quality of Beauveria bassiana.

    Science.gov (United States)

    Pérez-Guzmán, D; Montesinos-Matías, R; Arce-Cervantes, O; Gómez-Quiroz, L E; Loera, O; Garza-López, P M

    2016-08-01

    The aim of this study was to determine the relationship between reactive oxygen species (ROS) production and conidial infectivity in Beauveria bassiana. Beauveria bassiana Bb 882.5 was cultured in solid-state culture (SSC) using rice under three oxygen conditions (21%, or pulses at 16 and 26%). Hydrophobicity was determined using exclusion phase assay. Bioassays with larvae or adults of Tenebrio molitor allowed the measurements of infectivity parameters. A fluorometric method was used for ROS quantification (superoxide and total peroxides). NADPH oxidase (NOX) activity was determined by specific inhibition. Conidial hydrophobicity decreased by O2 pulses. Mortality of larvae was only achieved with conidia harvested from cultures under 21% O2 ; whereas for adult insects, the infectivity parameters deteriorated in conidia obtained after pulses at 16 and 26% O2 . At day 7, ROS production increased after 16 and 26% O2 treatments. NOX activity induced ROS production at early stages of the culture. Modification of atmospheric oxygen increases ROS production, reducing conidial quality and infectivity. This is the first study in which conidial infectivity and ROS production in B. bassiana has been related, enhancing the knowledge of the effect of O2 pulses in B. bassiana. © 2016 The Society for Applied Microbiology.

  10. The role of reactive oxygen species in the degradation of lignin derived dissolved organic matter

    Science.gov (United States)

    Waggoner, Derek C.; Wozniak, Andrew S.; Cory, Rose M.; Hatcher, Patrick G.

    2017-07-01

    Evidence suggests that reactive oxygen species (ROS) are important in transforming the chemical composition of the large pool of terrestrially-derived dissolved organic matter (DOM) exported from land to water annually. However, due to the challenges inherent in isolating the effects of individual ROS on DOM composition, the role of ROS in the photochemical alteration of DOM remains poorly characterized. In this work, terrestrial DOM was independently exposed to singlet oxygen (1O2), and superoxide (O2-rad under controlled laboratory conditions). Using ultra-high resolution mass spectrometry to track molecular level alterations of DOM by ROS, these findings suggest exposure to 1O2 (generated using Rose Bengal and visible light) removed formulas with an O/C > 0.3, and primarily resulted in DOM comprised of formulas with higher oxygen content, while O2-rad exposure (from KO2 in DMSO) removed formulas with O/C 1.5). Comparison of DOM altered by ROS in this study to riverine and coastal DOM showed that (20-80%) overlap in formulas, providing evidence for the role of ROS in shaping the composition of DOM exported from rivers to oceans.

  11. Covariance of oxygen and hydrogen isotopic composition in plant water: Species effects

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, L.W.; DeNiro, M.J. (Univ. of California, Los Angeles (United States))

    1989-12-01

    Leaf water becomes enriched in the heavy isotopes of oxygen and hydrogen during evapotranspiration. The magnitude of the enrichment has been shown to be influenced by temperature and humidity, but the effects of species-specific factors on leaf water enrichment of D and {sup 18}O have not been studied for different plants growing together. To learn whether leaf water enrichment patterns and processes for D and {sup 18}O are different for individual species growing under the same environmental conditions the authors tested the proposal that leaf waters in plants with crassulacean acid metabolism (CAM) show high sloped (m in the leaf water equation {delta}D = m {delta}{sup 18}O + b) than in C{sub 3} plants. They determined the relationships between the stable hydrogen ({delta}D) and oxygen ({delta}{sup 18}O) isotope ratios of leaf waters collected during the diurnal cycle of evapotranspiration for Yucca schidigera, Ephedra aspera, Agave deserti, Prunus ilicifolia, Yucca whipplei, Heteromeles arbutifolia, Dyckia fosteriana, Simmondsia chinensis, and Encelia farinosa growing at two sites in southern California. The findings indicate that m in the aforementioned equation is related to the overall residence time for water in the leaf and proportions of water subjected to repeated evapotranspiration enrichments of heavy isotopes.

  12. Electron Spin Resonance Spectroscopy for Studying the Generation and Scavenging of Reactive Oxygen Species by Nanomaterials

    Science.gov (United States)

    Yin, Jun-Jie; Zhao, Baozhong; Xia, Qingsu; Fu, Peter P.

    2013-09-01

    One fundamental mechanism widely described for nanotoxicity involves oxidative damage due to generation of free radicals and other reactive oxygen species. Indeed, the ability of nanoscale materials to facilitate the transfer of electrons, and thereby promote oxidative damage or in some instances provide antioxidant protection, may be a fundamental property of these materials. Any assessment of a nanoscale material's safety must therefore consider the potential for toxicity arising from oxidative damage. Therefore, rapid and predictive methods are needed to assess oxidative damage elicited by nanoscale materials. The use of electron spin resonance (ESR) to study free radical related bioactivity of nanomaterials has several advantages for free radical determination and identification. Specifically it can directly assess antioxidant quenching or prooxidant generation of relevant free radicals and reactive oxygen species. In this chapter, we have reported some nonclassical behaviors of the electron spin relaxation properties of unpaired electrons in different fullerenes and the investigation of anti/prooxidant activity by various types of nanomaterials using ESR. In addition, we have reviewed the mechanisms of free radical formation photosensitized by different nanomaterials. This chapter also included the use of spin labels, spin traps and ESR oximetry to systematically examine the enzymatic mimetic activities of nanomaterials.

  13. The Escherichia coli BtuE protein functions as a resistance determinant against reactive oxygen species.

    Directory of Open Access Journals (Sweden)

    Felipe A Arenas

    2011-01-01

    Full Text Available This work shows that the recently described Escherichia coli BtuE peroxidase protects the bacterium against oxidative stress that is generated by tellurite and by other reactive oxygen species elicitors (ROS. Cells lacking btuE (ΔbtuE displayed higher sensitivity to K(2TeO(3 and other oxidative stress-generating agents than did the isogenic, parental, wild-type strain. They also exhibited increased levels of cytoplasmic reactive oxygen species, oxidized proteins, thiobarbituric acid reactive substances, and lipoperoxides. E. coli ΔbtuE that was exposed to tellurite or H(2O(2 did not show growth changes relative to wild type cells either in aerobic or anaerobic conditions. Nevertheless, the elimination of btuE from cells deficient in catalases/peroxidases (Hpx(- resulted in impaired growth and resistance to these toxicants only in aerobic conditions, suggesting that BtuE is involved in the defense against oxidative damage. Genetic complementation of E. coli ΔbtuE restored toxicant resistance to levels exhibited by the wild type strain. As expected, btuE overexpression resulted in decreased amounts of oxidative damage products as well as in lower transcriptional levels of the oxidative stress-induced genes ibpA, soxS and katG.

  14. Candida albicans Biofilms Do Not Trigger Reactive Oxygen Species and Evade Neutrophil Killing

    Science.gov (United States)

    Xie, Zhihong; Thompson, Angela; Sobue, Takanori; Kashleva, Helena; Xu, Hongbin; Vasilakos, John; Dongari-Bagtzoglou, Anna

    2012-01-01

    Neutrophils are found within Candida albicans biofilms in vivo and could play a crucial role in clearing the pathogen from biofilms forming on catheters and mucosal surfaces. Our goal was to compare the antimicrobial activity of neutrophils against developing and mature C. albicans biofilms and identify biofilm-specific properties mediating resistance to immune cells. Antibiofilm activity was measured with the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)2H-tetrazolium-5-carboxanilide assay and a molecular Candida viability assay. Reactive oxygen species generation was assessed by measuring fluorescence of 5-(and-6)-chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate, acetyl ester in preloaded neutrophils. We found that mature biofilms were resistant to leukocytic killing and did not trigger reactive oxygen species, even though neutrophils retained their viability and functional activation potential. Beta-glucans found in the extracellular matrix negatively affected antibiofilm activities. We conclude that these polymers act as a decoy mechanism to prevent neutrophil activation and that this represents an important innate immune evasion mechanism of C. albicans biofilms. PMID:23033146

  15. Reactive oxygen species and lipid peroxidation product-scavenging ability of yogurt organisms.

    Science.gov (United States)

    Lin, M Y; Yen, C L

    1999-08-01

    The antioxidative activity of the intracellular extracts of yogurt organisms was investigated. All 11 strains tested, including five strains of Streptococcus thermophilus and six strains of Lactobacillus delbrueckii ssp. bulgaricus, demonstrated an antioxidative effect on the inhibition of linoleic acid peroxidation. The antioxidative effect of intracellular extracts of 10(8) cells of yogurt organisms was equivalent to 25 to 96 ppm butylated hydroxytoluene, which indicated that all strains demonstrated excellent antioxidative activity. The scavenging of reactive oxygen species, hydroxyl radical, and hydrogen peroxide was studied for intracellular extracts of yogurt organisms. All strains showed reactive oxygen species-scavenging ability. Lactobacillus delbrueckii ssp. bulgaricus Lb demonstrated the highest hydroxyl radical-scavenging ability at 234 microM. Streptococcus thermophilus MC and 821 and L. delbrueckii ssp. bulgaricus 448 and 449 scavenged the most hydrogen peroxide at approximately 50 microM. The scavenging ability of lipid peroxidation products, t-butylhydroperoxide and malondialdehyde, was also evaluated. Results showed that the extracts were not able to scavenge the t-butylhydroperoxide. Nevertheless, malondialdehyde was scavenged well by most strains.

  16. Photoluminescent Gold Nanoclusters in Cancer Cells: Cellular Uptake, Toxicity, and Generation of Reactive Oxygen Species.

    Science.gov (United States)

    Matulionyte, Marija; Dapkute, Dominyka; Budenaite, Laima; Jarockyte, Greta; Rotomskis, Ricardas

    2017-02-10

    In recent years, photoluminescent gold nanoclusters have attracted considerable interest in both fundamental biomedical research and practical applications. Due to their ultrasmall size, unique molecule-like optical properties, and facile synthesis gold nanoclusters have been considered very promising photoluminescent agents for biosensing, bioimaging, and targeted therapy. Yet, interaction of such ultra-small nanoclusters with cells and other biological objects remains poorly understood. Therefore, the assessment of the biocompatibility and potential toxicity of gold nanoclusters is of major importance before their clinical application. In this study, the cellular uptake, cytotoxicity, and intracellular generation of reactive oxygen species (ROS) of bovine serum albumin-encapsulated (BSA-Au NCs) and 2-(N-morpholino) ethanesulfonic acid (MES)capped photoluminescent gold nanoclusters (Au-MES NCs) were investigated. The results showed that BSA-Au NCs accumulate in cells in a similar manner as BSA alone, indicating an endocytotic uptake mechanism while ultrasmall Au-MES NCs were distributed homogeneously throughout the whole cell volume including cell nucleus. The cytotoxicity of BSA-Au NCs was negligible, demonstrating good biocompatibility of such BSA-protected Au NCs. In contrast, possibly due to ultrasmall size and thin coating layer, Au-MES NCs exhibited exposure time-dependent high cytotoxicity and higher reactivity which led to highly increased generation of reactive oxygen species. The results demonstrate the importance of the coating layer to biocompatibility and toxicity of ultrasmall photoluminescent gold nanoclusters.

  17. Photoluminescent Gold Nanoclusters in Cancer Cells: Cellular Uptake, Toxicity, and Generation of Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Marija Matulionyte

    2017-02-01

    Full Text Available In recent years, photoluminescent gold nanoclusters have attracted considerable interest in both fundamental biomedical research and practical applications. Due to their ultrasmall size, unique molecule-like optical properties, and facile synthesis gold nanoclusters have been considered very promising photoluminescent agents for biosensing, bioimaging, and targeted therapy. Yet, interaction of such ultra-small nanoclusters with cells and other biological objects remains poorly understood. Therefore, the assessment of the biocompatibility and potential toxicity of gold nanoclusters is of major importance before their clinical application. In this study, the cellular uptake, cytotoxicity, and intracellular generation of reactive oxygen species (ROS of bovine serum albumin-encapsulated (BSA-Au NCs and 2-(N-morpholino ethanesulfonic acid (MEScapped photoluminescent gold nanoclusters (Au-MES NCs were investigated. The results showed that BSA-Au NCs accumulate in cells in a similar manner as BSA alone, indicating an endocytotic uptake mechanism while ultrasmall Au-MES NCs were distributed homogeneously throughout the whole cell volume including cell nucleus. The cytotoxicity of BSA-Au NCs was negligible, demonstrating good biocompatibility of such BSA-protected Au NCs. In contrast, possibly due to ultrasmall size and thin coating layer, Au-MES NCs exhibited exposure time-dependent high cytotoxicity and higher reactivity which led to highly increased generation of reactive oxygen species. The results demonstrate the importance of the coating layer to biocompatibility and toxicity of ultrasmall photoluminescent gold nanoclusters.

  18. Reactive oxygen species and nitric oxide in plant mitochondria: origin and redundant regulatory systems.

    Science.gov (United States)

    Blokhina, Olga; Fagerstedt, Kurt V

    2010-04-01

    Plant mitochondria differ from their mammalian counterparts in many respects, which are due to the unique and variable surroundings of plant mitochondria. In green leaves, plant mitochondria are surrounded by ample respiratory substrates and abundant molecular oxygen, both resulting from active photosynthesis, while in roots and bulky rhizomes and fruit carbohydrates may be plenty, whereas oxygen levels are falling. Several enzymatic complexes in mitochondrial electron transport chain (ETC) are capable of reactive oxygen species (ROS) formation under physiological and pathological conditions. Inherently connected parameters such as the redox state of electron carriers in the ETC, ATP synthase activity and inner mitochondrial membrane potential, when affected by external stimuli, can give rise to ROS formation via complexes I and III, and by reverse electron transport (RET) from complex II. Superoxide radicals produced are quickly scavenged by superoxide dismutase (MnSOD), and the resulting H(2)O(2) is detoxified by peroxiredoxin-thioredoxin system or by the enzymes of ascorbate-glutathione cycle, found in the mitochondrial matrix. Arginine-dependent nitric oxide (NO)-releasing activity of enzymatic origin has been detected in plant mitochondria. The molecular identity of the enzyme is not clear but the involvement of mitochondria-localized enzymes responsible for arginine catabolism, arginase and ornithine aminotransferase has been shown in the regulation of NO efflux. Besides direct control by antioxidants, mitochondrial ROS production is tightly controlled by multiple redundant systems affecting inner membrane potential: NAD(P)H-dependent dehydrogenases, alternative oxidase (AOX), uncoupling proteins, ATP-sensitive K(+) channel and a number of matrix and intermembrane enzymes capable of direct electron donation to ETC. NO removal, on the other hand, takes place either by reactions with molecular oxygen or superoxide resulting in peroxynitrite, nitrite or nitrate

  19. A new Legionella species, Legionella feeleii species nova, causes Pontiac fever in an automobile plant.

    Science.gov (United States)

    Herwaldt, L A; Gorman, G W; McGrath, T; Toma, S; Brake, B; Hightower, A W; Jones, J; Reingold, A L; Boxer, P A; Tang, P W

    1984-03-01

    From 15 to 21 August 1981, Pontiac fever affected 317 automobile assembly plant workers. Results of serologic tests were negative for Mycoplasma, Chlamydia, respiratory tract viruses, and previously described legionellae. A gram-negative, rod-shaped organism (WO-44C) that did not grow on blood agar, required L-cysteine for growth, and contained large amounts of branched-chain fatty acids was isolated from a water-based coolant. The organism did not react with antisera against other legionellae, and on DNA hybridization the organism was less than 10% related to other Legionella species. Geometric mean titers found by indirect fluorescent antibody testing to WO-44C were significantly higher in ill employees than in controls (p = 0.0001). Attack rates by department decreased linearly with the department's distance from the implicated coolant system. The etiologic agent apparently was a new Legionella species; we propose the name Legionella feeleii species nova (AATC 35072). This is the first outbreak of nonpneumonic legionellosis in which the etiologic agent is not L. pneumophila, serogroup 1.

  20. QUANTIFYING AND MODELING THE RISK OF DISTURBANCE TO ECOSYSTEMS CAUSED BY INVASIVE SPECIES

    Science.gov (United States)

    Invasive species are biological pollutants that threaten ecosystem health. Identifying the mechanisms of invasive and developing predictive models of invasion will be critical to developing risk management strategies for limiting the economic and environmental damage caused by i...

  1. Comparative ecology of capsular Exophiala species causing disseminated infection in humans

    NARCIS (Netherlands)

    Song, Y. (Yinggai); Laureijssen-van de Sande, W.W.J. (Wendy W.J.); Moreno, L.F. (Leandro F.); van den Ende, B.G. (Bert Gerrits); Li, R. (Ruoyu); S. de Hoog (Sybren)

    2017-01-01

    textabstractExophiala spinifera and Exophiala dermatitidis (Fungi: Chaetothyriales) are black yeast agents potentially causing disseminated infection in apparently healthy humans. They are the only Exophiala species producing extracellular polysaccharides around yeast cells. In order to gain

  2. Effect of polyunsaturated fatty acids on the reactive oxygen and nitrogen species production by raw 264.7 macrophages

    Czech Academy of Sciences Publication Activity Database

    Ambrožová, Gabriela; Pekarová, Michaela; Lojek, Antonín

    2010-01-01

    Roč. 49, č. 3 (2010), s. 133-139 ISSN 1436-6207 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : polyunsaturated fatty acids * reactive oxygen species * reactive nitrogen species Subject RIV: BO - Biophysics Impact factor: 3.343, year: 2010

  3. Pyricularia graminis-tritici, a new Pyricularia species causing wheat blast

    NARCIS (Netherlands)

    Castroagudín, V.L.; Moreira, S.I.; Pereira, D.A.S.; Moreira, S.S.; Brunner, P.C.; Maciel, J.L.N.; Crous, P.W.; McDonald, B.A.; Alves, E.; Ceresini, P.C.

    2016-01-01

    Pyricularia oryzae is a species complex that causes blast disease on more than 50 species of poaceous plants. Pyricularia oryzae has a worldwide distribution as a rice pathogen and in the last 30 years emerged as an important wheat pathogen in southern Brazil. We conducted phylogenetic analyses

  4. Reactive oxygen species are involved in lipopolysaccharide-induced intrauterine growth restriction and skeletal development retardation in mice.

    Science.gov (United States)

    Xu, De-Xiang; Chen, Yuan-Hua; Zhao, Lei; Wang, Hua; Wei, Wei

    2006-12-01

    Maternal infection is a cause of adverse developmental outcomes including embryonic resorption, intrauterine fetal death, and preterm labor. Lipopolysaccharide-induced developmental toxicity at early gestational stages has been well characterized. The purpose of the present study was to investigate the effects of maternal lipopolysaccharide exposure at late gestational stages on intrauterine fetal growth and skeletal development and to assess the potential role of reactive oxygen species in lipopolysaccharide-induced intrauterine fetal growth restriction and skeletal development retardation. The timed pregnant CD-1 mice were intraperitoneally injected with lipopolysaccharide (25 to 75 microg/kg per day) on gestational day 15 to 17. To investigate the role of reactive oxygen species on lipopolysaccharide-induced intrauterine fetal growth restriction and skeletal development retardation, the pregnant mice were injected with alpha-phenyl-N-t-butylnitrone (100 mg/kg, intraperitoneally) at 30 minutes before lipopolysaccharide (75 microg/kg per day, intraperitoneally), followed by an additional dose of alpha-phenyl-N-t-butylnitrone (50 mg/kg, intraperitoneally) at 3 hours after lipopolysaccharide. The number of live fetuses, dead fetuses, and resorption sites was counted on gestational day 18. Live fetuses in each litter were weighed. Crown-rump and tail lengths were examined and skeletal development was evaluated. Maternal lipopolysaccharide exposure significantly increased fetal mortality, reduced fetal weight and crown-rump and tail lengths of live fetuses, and retarded skeletal ossification in caudal vertebrae, anterior and posterior phalanges, and supraoccipital bone in a dose-dependent manner. Alpha-phenyl-N-t-butylnitrone, a free radical spin-trapping agent, almost completely blocked lipopolysaccharide-induced fetal death (63.2% in lipopolysaccharide group versus 6.5% in alpha-phenyl-N-t-butylnitrone + lipopolysaccharide group, P intrauterine growth restriction

  5. Promotion of hydrogen entry into iron from NaOH solution by iron-oxygen species

    International Nuclear Information System (INIS)

    Flis-Kabulska, I.; Flis, J.; Zakroczymski, T.

    2007-01-01

    This study was carried out to explain reasons of the enhanced hydrogen entry into iron at low polarisations. Hydrogen permeation rate (HPR) through a 35-μm thick iron membrane was studied with the electrochemical technique in 0.1 M NaOH at 25 o C. A rotating split-ring disk electrode was used to detect soluble Fe(II) species. Enhanced hydrogen entry (HPR peaks) was observed at low cathodic and low anodic polarisations during voltammetric cycling, and also during galvanostatic anodic polarisation applied after cathodic charging. HPR peaks occurred at potentials from about -1.2 to -0.9 V (NHE) which were more cathodic than the potentials of thermodynamic stability of Fe(OH) 2 or Fe 3 O 4 , and of the formation of soluble Fe(II) species. It has been suggested that the enhanced hydrogen entry is associated with the presence of FeOH ad . In this species oxygen is bound with hydrogen (oxo-hydride), hence it can be supposed that the mechanism of its promoting effect can be similar to that of hydrides of other elements of the VIb group

  6. Generation of reactive oxygen species (ROS) is a key factor for stimulation of macrophage proliferation by ceramide 1-phosphate

    International Nuclear Information System (INIS)

    Arana, Lide; Gangoiti, Patricia; Ouro, Alberto; Rivera, Io-Guané; Ordoñez, Marta; Trueba, Miguel; Lankalapalli, Ravi S.; Bittman, Robert; Gomez-Muñoz, Antonio

    2012-01-01

    We previously demonstrated that ceramide 1-phosphate (C1P) is mitogenic for fibroblasts and macrophages. However, the mechanisms involved in this action were only partially described. Here, we demonstrate that C1P stimulates reactive oxygen species (ROS) formation in primary bone marrow-derived macrophages, and that ROS are required for the mitogenic effect of C1P. ROS production was dependent upon prior activation of NADPH oxidase by C1P, which was determined by measuring phosphorylation of the p40phox subunit and translocation of p47phox from the cytosol to the plasma membrane. In addition, C1P activated cytosolic calcium-dependent phospholipase A 2 and protein kinase C-α, and NADPH oxidase activation was blocked by selective inhibitors of these enzymes. These inhibitors, and inhibitors of ROS production, blocked the mitogenic effect of C1P. By using BHNB-C1P (a photolabile caged-C1P analog), we demonstrate that all of these C1P actions are caused by intracellular C1P. It can be concluded that the enzyme responsible for C1P-stimulated ROS generation in bone marrow-derived macrophages is NADPH oxidase, and that this enzyme is downstream of PKC-α and cPLA 2 -α in this pathway. -- Highlights: ► Ceramide 1-phosphate (C1P) stimulates reactive oxygen species (ROS) formation. ► The enzyme responsible for ROS generation by C1P in macrophages is NADPH oxidase. ► NADPH oxidase lies downstream of cPLA 2 -α and PKC-α in this pathway. ► ROS generation is essential for the stimulation of macrophage proliferation by C1P.

  7. Diffusion of a multi-species component and its role in oxygen and water transport in silicates

    Science.gov (United States)

    Zhang, Youxue; Stolper, E. M.; Wasserburg, G. J.

    1991-01-01

    The diffusion of a multispecies component is complicated by the different diffusion coefficient of each species and the interconversion reactions among the species. A diffusion equation is derived that incorporates the diffusive fluxes of all species contributing to the component's concentration. The effect of speciation on diffusion is investigated experimentally by measuring concentration profiles of all species developed during diffusion experiments. Data on water diffusion in rhyolitic glasses indicate that H2O molecules predominate over OH groups as the diffusing species at very low to high water concentrations. A simple theoretical relationship is drawn between the effective total oxygen diffusion coefficient and the total water concentration of silicates at low water content.

  8. Depletion of oxygen, nitrate and nitrite in the Peruvian oxygen minimum zone cause an imbalance of benthic nitrogen fluxes

    Science.gov (United States)

    Sommer, S.; Gier, J.; Treude, T.; Lomnitz, U.; Dengler, M.; Cardich, J.; Dale, A. W.

    2016-06-01

    Oxygen minimum zones (OMZ) are key regions for fixed nitrogen loss in both the sediments and the water column. During this study, the benthic contribution to N cycling was investigated at ten sites along a depth transect (74-989 m) across the Peruvian OMZ at 12°S. O2 levels were below detection limit down to ~500 m. Benthic fluxes of N2, NO3-, NO2-, NH4+, H2S and O2 were measured using benthic landers. Flux measurements on the shelf were made under extreme geochemical conditions consisting of a lack of O2, NO3- and NO2- in the bottom water and elevated seafloor sulphide release. These particular conditions were associated with a large imbalance in the benthic nitrogen cycle. The sediments on the shelf were densely covered by filamentous sulphur bacteria Thioploca, and were identified as major recycling sites for DIN releasing high amounts of NH4+up to 21.2 mmol m-2 d-1 that were far in excess of NH4+ release by ammonification. This difference was attributed to dissimilatory nitrate (or nitrite) reduction to ammonium (DNRA) that was partly being sustained by NO3- stored within the sulphur oxidizing bacteria. Sediments within the core of the OMZ (ca. 200-400 m) also displayed an excess flux of N of 3.5 mmol m-2 d-1 mainly as N2. Benthic nitrogen and sulphur cycling in the Peruvian OMZ appears to be particularly susceptible to bottom water fluctuations in O2, NO3- and NO2-, and may accelerate the onset of pelagic euxinia when NO3- and NO2- become depleted.

  9. Real-Time In Vivo Monitoring of Reactive Oxygen Species in Guard Cells.

    Science.gov (United States)

    Park, Ky Young; Roubelakis-Angelakis, Kalliopi A

    2018-01-01

    The intra-/intercellular homeostasis of reactive oxygen species (ROS), and especially of superoxides (O 2 .- ) and hydrogen peroxide (O 2 .- ) participate in signalling cascades which dictate developmental processes and reactions to biotic/abiotic stresses. Polyamine oxidases terminally oxidize/back convert polyamines generating H 2 O 2 . Recently, an NADPH-oxidase/Polyamine oxidase feedback loop was identified to control oxidative burst under salinity. Thus, the real-time localization/monitoring of ROS in specific cells, such as the guard cells, can be of great interest. Here we present a detailed description of the real-time in vivo monitoring of ROS in the guard cells using H 2 O 2 - and O 2 .- specific fluorescing probes, which can be used for studying ROS accumulation generated from any source, including the amine oxidases-dependent pathway, during development and stress.

  10. Chaetocin reactivates the lytic replication of Epstein-Barr virus from latency via reactive oxygen species.

    Science.gov (United States)

    Zhang, Shilun; Yin, Juan; Zhong, Jiang

    2017-01-01

    Oxidative stress, regarded as a negative effect of free radicals in vivo, takes place when organisms suffer from harmful stimuli. Some viruses can induce the release of reactive oxygen species (ROS) in infected cells, which may be closely related with their pathogenicity. In this report, chaetocin, a fungal metabolite reported to have antimicrobial and cytostatic activity, was studied for its effect on the activation of latent Epstein-Barr virus (EBV) in B95-8 cells. We found that chaetocin remarkably up-regulated EBV lytic transcription and DNA replication at a low concentration (50 nmol L -1 ). The activation of latent EBV was accompanied by an increased cellular ROS level. N-acetyl-L-cysteine (NAC), an ROS inhibitor, suppressed chaetocin-induced EBV activation. Chaetocin had little effect on histone H3K9 methylation, while NAC also significantly reduced H3K9 methylation. These results suggested that chaetocin reactivates latent EBV primarily via ROS pathways.

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

    Science.gov (United States)

    Schillinger, Kurt J.; Patel, Vickas V.

    2012-01-01

    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

  12. Research on killing Escherichia Coli by reactive oxygen species based on strong ionization discharging plasma

    International Nuclear Information System (INIS)

    Li, Y J; Tian, Y P; Zhang, Z T; Li, R H; Cai, L J; Gao, J Y

    2013-01-01

    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.

  13. Enhanced reactive oxygen species through direct copper sulfide nanoparticle-doxorubicin complexation

    Science.gov (United States)

    Li, Yajuan; Cupo, Michela; Guo, Liangran; Scott, Julie; Chen, Yi-Tzai; Yan, Bingfang; Lu, Wei

    2017-12-01

    CuS-based nanostructures loading the chemotherapeutic agent doxorubicin (DOX) exerted excellent cancer photothermal chemotherapy under multi-external stimuli. The DOX loading was generally designed through electrostatic interaction or chemical linkers. However, the interaction between DOX molecules and CuS nanoparticles has not been investigated. In this work, we use PEGylated hollow copper sulfide nanoparticles (HCuSNPs) to directly load DOX through the DOX/Cu2+ chelation process. Distinctively, the synthesized PEG-HCuSNPs-DOX release the DOX/Cu2+ complexes into surrounding environment, which generate significant reactive oxygen species (ROS) in a controlled manner by near-infrared laser. The CuS nanoparticle-mediated photothermal ablation facilitates the ROS-induced cancer cell killing effect. Our current work reveals a DOX/Cu2+-mediated ROS-enhanced cell-killing effect in addition to conventional photothermal chemotherapy through the direct CuS nanoparticle-DOX complexation.

  14. Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells

    International Nuclear Information System (INIS)

    Hong, Sung-Ha; Jenkins, A Toby A; Szili, Endre J; Short, Robert D

    2014-01-01

    This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine. (fast track communication)

  15. Temperature controls oxidative phosphorylation and reactive oxygen species production through uncoupling in rat skeletal muscle mitochondria.

    Science.gov (United States)

    Jarmuszkiewicz, Wieslawa; Woyda-Ploszczyca, Andrzej; Koziel, Agnieszka; Majerczak, Joanna; Zoladz, Jerzy A

    2015-06-01

    Mitochondrial respiratory and phosphorylation activities, mitochondrial uncoupling, and hydrogen peroxide formation were studied in isolated rat skeletal muscle mitochondria during experimentally induced hypothermia (25 °C) and hyperthermia (42 °C) compared to the physiological temperature of resting muscle (35 °C). For nonphosphorylating mitochondria, increasing the temperature from 25 to 42 °C led to a decrease in membrane potential, hydrogen peroxide production, and quinone reduction levels. For phosphorylating mitochondria, no temperature-dependent changes in these mitochondrial functions were observed. However, the efficiency of oxidative phosphorylation decreased, whereas the oxidation and phosphorylation rates and oxidative capacities of the mitochondria increased, with increasing assay temperature. An increase in proton leak, including uncoupling protein-mediated proton leak, was observed with increasing assay temperature, which could explain the reduced oxidative phosphorylation efficiency and reactive oxygen species production. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Reactive Oxygen Species-Mediated Mechanisms of Action of Targeted Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Hanna-Riikka Teppo

    2017-01-01

    Full Text Available Targeted cancer therapies, involving tyrosine kinase inhibitors and monoclonal antibodies, for example, have recently led to substantial prolongation of survival in many metastatic cancers. Compared with traditional chemotherapy and radiotherapy, where reactive oxygen species (ROS have been directly linked to the mediation of cytotoxic effects and adverse events, the field of oxidative stress regulation is still emerging in targeted cancer therapies. Here, we provide a comprehensive review regarding the current evidence of ROS-mediated effects of antibodies and tyrosine kinase inhibitors, use of which has been indicated in the treatment of solid malignancies and lymphomas. It can be concluded that there is rapidly emerging evidence of ROS-mediated effects of some of these compounds, which is also relevant in the context of drug resistance and how to overcome it.

  17. The Role of Heme and Reactive Oxygen Species in Proliferation and Survival of Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Marcia Cristina Paes

    2011-01-01

    Full Text Available Trypanosoma cruzi, the protozoan responsible for Chagas disease, has a complex life cycle comprehending two distinct hosts and a series of morphological and functional transformations. Hemoglobin degradation inside the insect vector releases high amounts of heme, and this molecule is known to exert a number of physiological functions. Moreover, the absence of its complete biosynthetic pathway in T. cruzi indicates heme as an essential molecule for this trypanosomatid survival. Within the hosts, T. cruzi has to cope with sudden environmental changes especially in the redox status and heme is able to increase the basal production of reactive oxygen species (ROS which can be also produced as byproducts of the parasite aerobic metabolism. In this regard, ROS sensing is likely to be an important mechanism for the adaptation and interaction of these organisms with their hosts. In this paper we discuss the main features of heme and ROS susceptibility in T. cruzi biology.

  18. Inactivation of pyruvate dehydrogenase kinase 2 by mitochondrial reactive oxygen species.

    Science.gov (United States)

    Hurd, Thomas R; Collins, Yvonne; Abakumova, Irina; Chouchani, Edward T; Baranowski, Bartlomiej; Fearnley, Ian M; Prime, Tracy A; Murphy, Michael P; James, Andrew M

    2012-10-12

    Reactive oxygen species are byproducts of mitochondrial respiration and thus potential regulators of mitochondrial function. Pyruvate dehydrogenase kinase 2 (PDHK2) inhibits the pyruvate dehydrogenase complex, thereby regulating entry of carbohydrates into the tricarboxylic acid (TCA) cycle. Here we show that PDHK2 activity is inhibited by low levels of hydrogen peroxide (H(2)O(2)) generated by the respiratory chain. This occurs via reversible oxidation of cysteine residues 45 and 392 on PDHK2 and results in increased pyruvate dehydrogenase complex activity. H(2)O(2) derives from superoxide (O(2)(.)), and we show that conditions that inhibit PDHK2 also inactivate the TCA cycle enzyme, aconitase. These findings suggest that under conditions of high mitochondrial O(2)(.) production, such as may occur under nutrient excess and low ATP demand, the increase in O(2)() and H(2)O(2) may provide feedback signals to modulate mitochondrial metabolism.

  19. The Injury and Therapy of Reactive Oxygen Species in Intracerebral Hemorrhage Looking at Mitochondria

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    Jie Qu

    2016-01-01

    Full Text Available Intracerebral hemorrhage is an emerging major health problem often resulting in death or disability. Reactive oxygen species (ROS have been identified as one of the major damaging factors in ischemic stroke. However, there is less discussion about ROS in hemorrhage stroke. Metabolic products of hemoglobin, excitatory amino acids, and inflammatory cells are all sources of ROS, and ROS harm the central nervous system through cell death and structural damage, especially disruption of the blood-brain barrier. We have considered the antioxidant system of the CNS itself and the drugs aiming to decrease ROS after ICH, and we find that mitochondria are key players in all of these aspects. Moreover, when the mitochondrial permeability transition pore opens, ROS-induced ROS release, which leads to extensive liberation of ROS and mitochondrial failure, occurs. Therefore, the mitochondrion may be a significant target for elucidating the problem of ROS in ICH; however, additional experimental support is required.

  20. Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells

    Science.gov (United States)

    Hong, Sung-Ha; Szili, Endre J.; Jenkins, A. Toby A.; Short, Robert D.

    2014-09-01

    This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine.

  1. Hemoglobin fructation promotes heme degradation through the generation of endogenous reactive oxygen species

    Science.gov (United States)

    Goodarzi, M.; Moosavi-Movahedi, A. A.; Habibi-Rezaei, M.; Shourian, M.; Ghourchian, H.; Ahmad, F.; Farhadi, M.; Saboury, A. A.; Sheibani, N.

    2014-09-01

    Protein glycation is a cascade of nonenzymatic reactions between reducing sugars and amino groups of proteins. It is referred to as fructation when the reducing monosaccharide is fructose. Some potential mechanisms have been suggested for the generation of reactive oxygen species (ROS) by protein glycation reactions in the presence of glucose. In this state, glucose autoxidation, ketoamine, and oxidative advance glycation end products (AGEs) formation are considered as major sources of ROS and perhaps heme degradation during hemoglobin glycation. However, whether fructose mediated glycation produces ROS and heme degradation is unknown. Here we report that ROS (H2O2) production occurred during hemoglobin fructation in vitro using chemiluminescence methods. The enhanced heme exposure and degradation were determined using UV-Vis and fluorescence spectrophotometry. Following accumulation of ROS, heme degradation products were accumulated reaching a plateau along with the detected ROS. Thus, fructose may make a significant contribution to the production of ROS, glycation of proteins, and heme degradation during diabetes.

  2. Horseradish peroxidase embedded in polyacrylamide nanoparticles enables optical detection of reactive oxygen species

    DEFF Research Database (Denmark)

    Poulsen, A.K.; Scharff-Poulsen, Anne Marie; Olsen, L.F.

    2007-01-01

    We have synthesized and characterized new nanometer-sized polyacrylamide particles containing horseradish peroxidase and fluorescent dyes. Proteins and dyes are encapsulated by radical polymerization in inverse microemulsion. The activity of the encapsulated enzyme has been examined and it mainta......We have synthesized and characterized new nanometer-sized polyacrylamide particles containing horseradish peroxidase and fluorescent dyes. Proteins and dyes are encapsulated by radical polymerization in inverse microemulsion. The activity of the encapsulated enzyme has been examined...... for quantification of hydrogen peroxide and other reactive oxygen species in microenvironments, and we propose that the particles may find use as nanosensors for use in, e.g., living cells. (C) 2007 Elsevier Inc. All rights reserved....

  3. Reactive oxygen species-related activities of nano-iron metal and nano-iron oxides.

    Science.gov (United States)

    Wu, Haohao; Yin, Jun-Jie; Wamer, Wayne G; Zeng, Mingyong; Lo, Y Martin

    2014-03-01

    Nano-iron metal and nano-iron oxides are among the most widely used engineered and naturally occurring nanostructures, and the increasing incidence of biological exposure to these nanostructures has raised concerns about their biotoxicity. Reactive oxygen species (ROS)-induced oxidative stress is one of the most accepted toxic mechanisms and, in the past decades, considerable efforts have been made to investigate the ROS-related activities of iron nanostructures. In this review, we summarize activities of nano-iron metal and nano-iron oxides in ROS-related redox processes, addressing in detail the known homogeneous and heterogeneous redox mechanisms involved in these processes, intrinsic ROS-related properties of iron nanostructures (chemical composition, particle size, and crystalline phase), and ROS-related bio-microenvironmental factors, including physiological pH and buffers, biogenic reducing agents, and other organic substances. Copyright © 2014. Published by Elsevier B.V.

  4. Using consensus bayesian network to model the reactive oxygen species regulatory pathway.

    Directory of Open Access Journals (Sweden)

    Liangdong Hu

    Full Text Available Bayesian network is one of the most successful graph models for representing the reactive oxygen species regulatory pathway. With the increasing number of microarray measurements, it is possible to construct the bayesian network from microarray data directly. Although large numbers of bayesian network learning algorithms have been developed, when applying them to learn bayesian networks from microarray data, the accuracies are low due to that the databases they used to learn bayesian networks contain too few microarray data. In this paper, we propose a consensus bayesian network which is constructed by combining bayesian networks from relevant literatures and bayesian networks learned from microarray data. It would have a higher accuracy than the bayesian networks learned from one database. In the experiment, we validated the bayesian network combination algorithm on several classic machine learning databases and used the consensus bayesian network to model the Escherichia coli's ROS pathway.

  5. ent-Jungermannenone C Triggers Reactive Oxygen Species-Dependent Cell Differentiation in Leukemia Cells.

    Science.gov (United States)

    Yue, Zongwei; Xiao, Xinhua; Wu, Jinbao; Zhou, Xiaozhou; Liu, Weilong; Liu, Yaxi; Li, Houhua; Chen, Guoqiang; Wu, Yingli; Lei, Xiaoguang

    2018-02-23

    Acute myeloid leukemia (AML) is a hematologic malignancy that is characterized by clonal proliferation of myeloid blasts. Despite the progress that has been made in the treatment of various malignant hematopoietic diseases, the effective treatment of AML remains very challenging. Differentiation therapy has emerged as a promising approach for leukemia treatment, and new and effective chemical agents to trigger the differentiation of AML cells, especially drug-resistant cells, are urgently required. Herein, the natural product jungermannenone C, a tetracyclic diterpenoid isolated from liverworts, is reported to induce cell differentiation in AML cells. Interestingly, the unnatural enantiomer of jungermannenone C (1) was found to be more potent than jungermannenone C in inducing cell differentiation. Furthermore, compound 1 targets peroxiredoxins I and II by selectively binding to the conserved cysteine residues and leads to cellular reactive oxygen species accumulation. Accordingly, ent-jungermannenone C (1) shows potential for further investigation as an effective differentiation therapy against AML.

  6. Reactive Oxygen and Nitrogen Species in the Development of Pulmonary Hypertension

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    David J.R. Fulton

    2017-07-01

    Full Text Available Pulmonary arterial hypertension (PAH is a progressive disease of the lung vasculature that involves the loss of endothelial function together with inappropriate smooth muscle cell growth, inflammation, and fibrosis. These changes underlie a progressive remodeling of blood vessels that alters flow and increases pulmonary blood pressure. Elevated pressures in the pulmonary artery imparts a chronic stress on the right ventricle which undergoes compensatory hypertrophy but eventually fails. How PAH develops remains incompletely understood and evidence for the altered production of reactive oxygen and nitrogen species (ROS, RNS respectively in the pulmonary circulation has been well documented. There are many different types of ROS and RNS, multiple sources, and collective actions and interactions. This review summarizes past and current knowledge of the sources of ROS and RNS and how they may contribute to the loss of endothelial function and changes in smooth muscle proliferation in the pulmonary circulation.

  7. Mitochondrial reactive oxygen species regulate the strength of inhibitory GABA-mediated synaptic transmission

    Science.gov (United States)

    Accardi, Michael V.; Daniels, Bryan A.; Brown, Patricia M. G. E.; Fritschy, Jean-Marc; Tyagarajan, Shiva K.; Bowie, Derek

    2014-01-01

    Neuronal communication imposes a heavy metabolic burden in maintaining ionic gradients essential for action potential firing and synaptic signalling. Although cellular metabolism is known to regulate excitatory neurotransmission, it is still unclear whether the brain’s energy supply affects inhibitory signalling. Here we show that mitochondrial-derived reactive oxygen species (mROS) regulate the strength of postsynaptic GABAA receptors at inhibitory synapses of cerebellar stellate cells. Inhibition is strengthened through a mechanism that selectively recruits α3-containing GABAA receptors into synapses with no discernible effect on resident α1-containing receptors. Since mROS promotes the emergence of postsynaptic events with unique kinetic properties, we conclude that newly recruited α3-containing GABAA receptors are activated by neurotransmitter released onto discrete postsynaptic sites. Although traditionally associated with oxidative stress in neurodegenerative disease, our data identify mROS as a putative homeostatic signalling molecule coupling cellular metabolism to the strength of inhibitory transmission.

  8. Influence of Vitamins on Secondary Reactive Oxygen Species Production in Sera of Patients with Resectable NSCLC

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    Thierry Patrice

    2016-07-01

    Full Text Available Background: Singlet oxygen (1O2 oxidizes targets through the production of secondary reactive oxygen species (SOS. Cancers induce oxidative stress changing with progression, the resulting antioxidant status differing from one patient to the other. The aim of this study was to determine the oxidative status of patients with resectable Non-Small cell lung cancers (NSCLC and the potential influence of antioxidants, compared to sera from healthy donors. Materials and Methods: Serum samples from 10 women and 28 men, 19 adenocarcinomas (ADK, 15 patients N1 or M1 were submitted to a photoreaction producing 1O2. Then, samples were supplemented with vitamins (Vit C, Vit E, or glutathione (GSH. Results: Squamous cell carcinomas (SCC and metastatic SCCs induced a lower SOS rate. While Vit C increased SOS in controls as in patients with metastases, Vit E or the combination of Vit E and C strongly reduced SOS. GSH alone lightly decreased SOS in controls but had no effect in patients either alone or combined with Vit C. Conclusion: In “early” lung cancers, SOS are comparable or lower than for healthy persons. The role of Vitamins varies with gender, cancer type, and metastases. This suggests that an eventual supplementation should be performed on a per-patient basis to evidence any effect.

  9. The role of metals in production and scavenging of reactive oxygen species in photosystem II.

    Science.gov (United States)

    Pospíšil, Pavel

    2014-07-01

    Metal ions play a crucial role in enzymatic reactions in all photosynthetic organisms such as cyanobacteria, algae and plants. It well known that metal ions maintain the binding of substrate in the active site of the metalloenzymes and control the redox activity of the metalloenzyme in the enzymatic reaction. A large pigment-protein complex, PSII, known to serve as a water-plastoquinone oxidoreductase, contains three metal centers comprising non-heme iron, heme iron of Cyt b559 and the water-splitting manganese complex. Metal ions bound to PSII proteins maintain the electron transport from water to plastoquinone and regulate the pro-oxidant and antioxidant activity in PSII. In this review, attention is focused on the role of PSII metal centers in (i) the formation of superoxide anion and hydroxyl radicals by sequential one-electron reduction of molecular oxygen and the formation of hydrogen peroxide by incomplete two-electron oxidation of water; and (ii) the elimination of superoxide anion radical by one-electron oxidation and reduction (superoxide dismutase activity) and of hydrogen peroxide by two-electron oxidation and reduction (catalase activity). The balance between the formation and elimination of reactive oxygen species by PSII metal centers is discussed as an important aspect in the prevention of photo-oxidative damage of PSII proteins and lipids. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  10. Effect of ectomycorrhizal colonization and drought on reactive oxygen species metabolism of Nothofagus dombeyi roots.

    Science.gov (United States)

    Alvarez, Maricel; Huygens, Dries; Fernandez, Carlos; Gacitúa, Yessy; Olivares, Erick; Saavedra, Isabel; Alberdi, Miren; Valenzuela, Eduardo

    2009-08-01

    Infection with ectomycorrhizal fungi can increase the ability of plants to resist drought stress through morphophysiological and biochemical mechanisms. However, the metabolism of antioxidative enzyme activities in the ectomycorrhizal symbiosis remains poorly understood. This study investigated biomass production, reactive oxygen metabolism (hydrogen peroxide and malondialdehyde concentration) and antioxidant enzyme activity (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) in pure cultures of the ectomycorrhizal fungi Descolea antartica Sing. and Pisolithus tinctorius (Pers.) Coker & Couch, and non-mycorrhizal and mycorrhizal roots of Nothofagus dombeyi (Mirb.) roots under well-watered conditions and drought conditions (DC). The studied ectomycorrhizal fungi regulated their antioxidative enzyme metabolism differentially in response to drought, resulting in cellular damage in D. antartica but not in P. tinctorius. Ectomycorrhizal inoculation and water treatment had a significant effect on all parameters studied, including relative water content of the plant. As such, N. dombeyi plants in symbiosis experienced a lower oxidative stress effect than non-mycorrhizal plants under DC. Additionally, ectomycorrhizal N. dombeyi roots showed a greater antioxidant enzyme activity relative to non-mycorrhizal roots, an effect which was further expressed under DC. The association between the non-specific P. tinctorius and N. dombeyi had a more effective reactive oxygen species (ROS) metabolism than the specific D. antartica-N. dombeyi symbiosis. We conclude that the combination of effective ROS prevention and ROS detoxification by ectomycorrhizal plants resulted in reduced cellular damage and increased plant growth relative to non-mycorrhizal plants under drought.

  11. Cross talk between increased intracellular zinc (Zn2+) and accumulation of reactive oxygen species in chemical ischemia.

    Science.gov (United States)

    Slepchenko, Kira G; Lu, Qiping; Li, Yang V

    2017-10-01

    Both zinc (Zn 2+ ) and reactive oxygen species (ROS) have been shown to accumulate during hypoxic-ischemic stress and play important roles in pathological processes. To understand the cross talk between the two of them, here we studied Zn 2+ and ROS accumulation by employing fluorescent probes in HeLa cells to further the understanding of the cause and effect relationship of these two important cellular signaling systems during chemical-ischemia, stimulated by oxygen and glucose deprivation (OGD). We observed two Zn 2+ rises that were divided into four phases in the course of 30 min of OGD. The first Zn 2+ rise was a transient, which was followed by a latent phase during which Zn 2+ levels recovered; however, levels remained above a basal level in most cells. The final phase was the second Zn 2+ rise, which reached a sustained plateau called Zn 2+ overload. Zn 2+ rises were not observed when Zn 2+ was removed by TPEN (a Zn 2+ chelator) or thapsigargin (depleting Zn 2+ from intracellular stores) treatment, indicating that Zn 2+ was from intracellular storage. Damaging mitochondria with FCCP significantly reduced the second Zn 2+ rise, indicating that the mitochondrial Zn 2+ accumulation contributes to Zn 2+ overload. We also detected two OGD-induced ROS rises. Two Zn 2+ rises preceded two ROS rises. Removal of Zn 2+ reduced or delayed OGD- and FCCP-induced ROS generation, indicating that Zn 2+ contributes to mitochondrial ROS generation. There was a Zn 2+ -induced increase in the functional component of NADPH oxidase, p47 phox , thus suggesting that NADPH oxidase may mediate Zn 2+ -induced ROS accumulation. We suggest a new mechanism of cross talk between Zn 2+ and mitochondrial ROS through positive feedback processes that eventually causes excessive free Zn 2+ and ROS accumulations during the course of ischemic stress. Copyright © 2017 the American Physiological Society.

  12. Mitochondrial Reactive Oxygen Species Mediate Cardiac Structural, Functional, and Mitochondrial Consequences of Diet-Induced Metabolic Heart Disease.

    Science.gov (United States)

    Sverdlov, Aaron L; Elezaby, Aly; Qin, Fuzhong; Behring, Jessica B; Luptak, Ivan; Calamaras, Timothy D; Siwik, Deborah A; Miller, Edward J; Liesa, Marc; Shirihai, Orian S; Pimentel, David R; Cohen, Richard A; Bachschmid, Markus M; Colucci, Wilson S

    2016-01-11

    Mitochondrial reactive oxygen species (ROS) are associated with metabolic heart disease (MHD). However, the mechanism by which ROS cause MHD is unknown. We tested the hypothesis that mitochondrial ROS are a key mediator of MHD. Mice fed a high-fat high-sucrose (HFHS) diet develop MHD with cardiac diastolic and mitochondrial dysfunction that is associated with oxidative posttranslational modifications of cardiac mitochondrial proteins. Transgenic mice that express catalase in mitochondria and wild-type mice were fed an HFHS or control diet for 4 months. Cardiac mitochondria from HFHS-fed wild-type mice had a 3-fold greater rate of H2O2 production (P=0.001 versus control diet fed), a 30% decrease in complex II substrate-driven oxygen consumption (P=0.006), 21% to 23% decreases in complex I and II substrate-driven ATP synthesis (P=0.01), and a 62% decrease in complex II activity (P=0.002). In transgenic mice that express catalase in mitochondria, all HFHS diet-induced mitochondrial abnormalities were ameliorated, as were left ventricular hypertrophy and diastolic dysfunction. In HFHS-fed wild-type mice complex II substrate-driven ATP synthesis and activity were restored ex vivo by dithiothreitol (5 mmol/L), suggesting a role for reversible cysteine oxidative posttranslational modifications. In vitro site-directed mutation of complex II subunit B Cys100 or Cys103 to redox-insensitive serines prevented complex II dysfunction induced by ROS or high glucose/high palmitate in the medium. Mitochondrial ROS are pathogenic in MHD and contribute to mitochondrial dysfunction, at least in part, by causing oxidative posttranslational modifications of complex I and II proteins including reversible oxidative posttranslational modifications of complex II subunit B Cys100 and Cys103. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  13. Botrytis californica, a new cryptic species in the B. cinerea species complex causing gray mold in blueberries and table grapes.

    Science.gov (United States)

    Saito, S; Margosan, D; Michailides, T J; Xiao, C L

    2016-01-01

    The Botrytis cinerea species complex comprises two cryptic species, originally referred to Group I and Group II based on Bc-hch gene RFLP haplotyping. Group I was described as a new cryptic species B. pseudocinerea During a survey of Botrytis spp. causing gray mold in blueberries and table grapes in the Central Valley of California, six isolates, three from blueberries and three from table grapes, were placed in Group I but had a distinct morphological character with conidiophores significantly longer than those of B. cinerea and B. pseudocinerea We compared these with B. cinerea and B. pseudocinerea by examining morphological and physiological characters, sensitivity to fenhexamid and phylogenetic analysis inferred from sequences of three nuclear genes. Phylogenetic analysis with the three partial gene sequences encoding glyceraldehyde-3-phosate dehydrogenase (G3PDH), heat-shock protein 60 (HSP60) and DNA-dependent RNA polymerase subunit II (RPB2) supported the proposal of a new Botrytis species, B. californica, which is closely related genetically to B. cinerea, B. pseudocinerea and B. sinoviticola, all known as causal agents of gray mold of grapes. Botrytis californica caused decay on blueberry and table grape fruit inoculated with the fungus. This study suggests that B. californica is a cryptic species sympatric with B. cinerea on blueberries and table grapes in California. © 2016 by The Mycological Society of America.

  14. Protective effects of myricitrin against osteoporosis via reducing reactive oxygen species and bone-resorbing cytokines

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qiang; Gao, Bo; Wang, Long; Hu, Ya-Qian; Lu, Wei-Guang; Yang, Liu; Luo, Zhuo-Jing; Liu, Jian, E-mail: liujianhq@sina.com

    2014-11-01

    Oxidative stress is a crucial pathogenic factor in the development of osteoporosis. Myricitrin, isolated from Myrica cerifera, is a potent antioxidant. We hypothesized that myricitrin possessed protective effects against osteoporosis by partially reducing reactive oxygen species (ROS) and bone-resorbing cytokines in osteoblastic MC3T3-E1 cells and human bone marrow stromal cells (hBMSCs). We investigated myricitrin on osteogenic differentiation under oxidative stress. Hydrogen peroxide (H{sub 2}O{sub 2}) was used to establish an oxidative cell injury model. Our results revealed that myricitrin significantly improved some osteogenic markers in these cells. Myricitrin decreased lipid production and reduced peroxisome proliferator-activated receptor gamma-2 (PPARγ2) expression in hBMSCs. Moreover, myricitrin reduced the expression of receptor activator of nuclear factor kappa-B ligand (RANKL) and IL-6 and partially suppressed ROS production. In vivo, we established a murine ovariectomized (OVX) osteoporosis model. Our results demonstrated that myricitrin supplementation reduced serum malondialdehyde (MDA) activity and increased reduced glutathione (GSH) activity. Importantly, it ameliorated the micro-architecture of trabecular bones in the 4th lumbar vertebrae (L4) and distal femur. Taken together, these results indicated that the protective effects of myricitrin against osteoporosis are linked to a reduction in ROS and bone-resorbing cytokines, suggesting that myricitrin may be useful in bone metabolism diseases, particularly osteoporosis. - Highlights: • Myricitrin protects MC3T3-E1 cells and hBMSCs from oxidative stress. • It is accompanied by a decrease in oxidative stress and bone-resorbing cytokines. • Myricitrin decreases serum reactive oxygen species to some degree. • Myricitrin partly reverses ovariectomy effects in vivo. • Myricitrin may represent a beneficial anti-osteoporosis treatment method.

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

    Directory of Open Access Journals (Sweden)

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

    2012-01-01

    Full Text Available 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 μM 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.

  16. Reactive Oxygen Species Production by Forward and Reverse Electron Fluxes in the Mitochondrial Respiratory Chain

    Science.gov (United States)

    Selivanov, Vitaly A.; Votyakova, Tatyana V.; Pivtoraiko, Violetta N.; Zeak, Jennifer; Sukhomlin, Tatiana; Trucco, Massimo; Roca, Josep; Cascante, Marta

    2011-01-01

    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. PMID:21483483

  17. Reactive Oxygen Species Play a Role in the Infection of the Necrotrophic Fungi, Rhizoctonia solani in Wheat.

    Science.gov (United States)

    Foley, Rhonda C; Kidd, Brendan N; Hane, James K; Anderson, Jonathan P; Singh, Karam B

    2016-01-01

    Rhizoctonia solani is a nectrotrophic fungal pathogen that causes billions of dollars of damage to agriculture worldwide and infects a broad host range including wheat, rice, potato and legumes. In this study we identify wheat genes that are differentially expressed in response to the R. solani isolate, AG8, using microarray technology. A significant number of wheat genes identified in this screen were involved in reactive oxygen species (ROS) production and redox regulation. Levels of ROS species were increased in wheat root tissue following R. solani infection as determined by Nitro Blue Tetrazolium (NBT), 3,3'-diaminobenzidine (DAB) and titanium sulphate measurements. Pathogen/ROS related genes from R. solani were also tested for expression patterns upon wheat infection. TmpL, a R. solani gene homologous to a gene associated with ROS regulation in Alternaria brassicicola, and OAH, a R. solani gene homologous to oxaloacetate acetylhydrolase which has been shown to produce oxalic acid in Sclerotinia sclerotiorum, were highly induced in R. solani when infecting wheat. We speculate that the interplay between the wheat and R. solani ROS generating proteins may be important for determining the outcome of the wheat/R. solani interaction.

  18. Reactive Oxygen Species Play a Role in the Infection of the Necrotrophic Fungi, Rhizoctonia solani in Wheat.

    Directory of Open Access Journals (Sweden)

    Rhonda C Foley

    Full Text Available Rhizoctonia solani is a nectrotrophic fungal pathogen that causes billions of dollars of damage to agriculture worldwide and infects a broad host range including wheat, rice, potato and legumes. In this study we identify wheat genes that are differentially expressed in response to the R. solani isolate, AG8, using microarray technology. A significant number of wheat genes identified in this screen were involved in reactive oxygen species (ROS production and redox regulation. Levels of ROS species were increased in wheat root tissue following R. solani infection as determined by Nitro Blue Tetrazolium (NBT, 3,3'-diaminobenzidine (DAB and titanium sulphate measurements. Pathogen/ROS related genes from R. solani were also tested for expression patterns upon wheat infection. TmpL, a R. solani gene homologous to a gene associated with ROS regulation in Alternaria brassicicola, and OAH, a R. solani gene homologous to oxaloacetate acetylhydrolase which has been shown to produce oxalic acid in Sclerotinia sclerotiorum, were highly induced in R. solani when infecting wheat. We speculate that the interplay between the wheat and R. solani ROS generating proteins may be important for determining the outcome of the wheat/R. solani interaction.

  19. Reactive oxygen species' role in endothelial dysfunction by electron paramagnetic resonance

    Science.gov (United States)

    Wassall, Cynthia D.

    The endothelium is a single layer of cells lining the arteries and is involved in many physiological reactions which are responsible for vascular tone. Free radicals are important participants in these chemical reactions in the endothelium. Here we quantify free radicals, ex vivo, in biological tissue with continuous wave electron paramagnetic resonance (EPR). In all of the experiments in this thesis, we use a novel EPR spin trapping technique that has been developed for tissue segments. EPR spin trapping is often considered the 'gold standard' in reactive oxygen species (ROS) detection because of its sensitivity and non-invasive nature. In all experiments, tissue was placed in physiological saline solution with 190-mM PBN (N-tert -butyl-α-phenylnitrone), 10% by volume dimethyl-sulphoxide (DMSO) for cryopreservation, and incubated in the dark for between 30 minutes up to 2 hours at 37°C while gently being stirred. Tissue and supernatant were then loaded into a syringe and frozen at -80°C until EPR analysis. In our experiments, the EPR spectra were normalized with respect to tissue volume. Conducting experiments at liquid nitrogen temperature leads to some experimental advantages. The freezing of the spin adducts renders them stable over a longer period, which allows ample time to analyze tissue samples for ROS. The dielectric constant of ice is greatly reduced over its liquid counterpart; this property of water enables larger sample volumes to be inserted into the EPR cavity without overloading it and leads to enhanced signal detection. Due to Maxwell-Boltzmann statistics, the population difference goes up as the temperature goes down, so this phenomenon enhances the signal intensity as well. With the 'gold standard' assertion in mind, we investigated whether slicing tissue to assay ROS that is commonly used in fluorescence experiments will show more free radical generation than tissue of a similar volume that remains unsliced. Sliced tissue exhibited a 76

  20. Shifts in coastal sediment oxygenation cause pronounced changes in microbial community composition and associated metabolism

    DEFF Research Database (Denmark)

    Broman, Elias; Sjöstedt, Johanna; Pinhassi, Jarone

    2017-01-01

    . In particular, the intermediate site sediments responded differently upon oxygenation compared to the anoxic and oxic site sediments. This included a microbial community composition with more habitat generalists, lower amounts of RNA transcripts attributed to methane oxidation, and a reduced rate of organic...... efforts, depend largely on the oxygenation history of sites. Furthermore, it was shown that re-oxygenation efforts to remediate dead zones could ultimately be facilitated by in situ microbial molecular mechanisms involved in removal of toxic H2S and the potent greenhouse gas methane....

  1. Induction of reactive oxygen species in marine phytoplankton under crude oil exposure.

    Science.gov (United States)

    Ozhan, Koray; Zahraeifard, Sara; Smith, Aaron P; Bargu, Sibel

    2015-12-01

    Exposure of phytoplankton to the water-accommodated fraction of crude oil can elicit a number of stress responses, but the mechanisms that drive these responses are unclear. South Louisiana crude oil was selected to investigate its effects on population growth, chlorophyll a (Chl a) content, antioxidative defense, and lipid peroxidation, for the marine diatom, Ditylum brightwellii, and the dinoflagellate, Heterocapsa triquetra, in laboratory-based microcosm experiments. The transcript levels of several possible stress-responsive genes in D. brightwellii were also measured. The microalgae were exposed to crude oil for up to 96 h, and Chl a content, superoxide dismutase (SOD), the glutathione pool (GSH and GSSG), and lipid peroxidation content were analyzed. The cell growth of both phytoplankton species was inhibited with increasing crude oil concentrations. Crude oil exposure did not affect Chl a content significantly in cells. SOD activities showed similar responses in both species, being enhanced at 4- and 8-mg/L crude oil exposure. Only H. triquetra demonstrated enhanced activity in GSSG pool and lipid peroxidation at 8-mg/L crude oil exposure, suggesting that phytoplankton species have distinct physiological responses and tolerance levels to crude oil exposure. This study indicated the activation of reactive oxygen species (ROS) in phytoplankton under crude oil exposure; however, the progressive damage in cells is still unknown. Thus, ROS-related damage in nucleic acid, lipids, proteins, and DNA, due to crude oil exposure could be a worthwhile subject of study to better understand crude oil toxicity at the base of the food web.

  2. Shifts in coastal sediment oxygenation cause pronounced changes in microbial community composition and associated metabolism.

    Science.gov (United States)

    Broman, Elias; Sjöstedt, Johanna; Pinhassi, Jarone; Dopson, Mark

    2017-08-09

    A key characteristic of eutrophication in coastal seas is the expansion of hypoxic bottom waters, often referred to as 'dead zones'. One proposed remediation strategy for coastal dead zones in the Baltic Sea is to mix the water column using pump stations, circulating oxygenated water to the sea bottom. Although microbial metabolism in the sediment surface is recognized as key in regulating bulk chemical fluxes, it remains unknown how the microbial community and its metabolic processes are influenced by shifts in oxygen availability. Here, coastal Baltic Sea sediments sampled from oxic and anoxic sites, plus an intermediate area subjected to episodic oxygenation, were experimentally exposed to oxygen shifts. Chemical, 16S rRNA gene, metagenomic, and metatranscriptomic analyses were conducted to investigate changes in chemistry fluxes, microbial community structure, and metabolic functions in the sediment surface. Compared to anoxic controls, oxygenation of anoxic sediment resulted in a proliferation of bacterial populations in the facultative anaerobic genus Sulfurovum that are capable of oxidizing toxic sulfide. Furthermore, the oxygenated sediment had higher amounts of RNA transcripts annotated as sqr, fccB, and dsrA involved in sulfide oxidation. In addition, the importance of cryptic sulfur cycling was highlighted by the oxidative genes listed above as well as dsvA, ttrB, dmsA, and ddhAB that encode reductive processes being identified in anoxic and intermediate sediments turned oxic. In particular, the intermediate site sediments responded differently upon oxygenation compared to the anoxic and oxic site sediments. This included a microbial community composition with more habitat generalists, lower amounts of RNA transcripts attributed to methane oxidation, and a reduced rate of organic matter degradation. These novel data emphasize that genetic expression analyses has the power to identify key molecular mechanisms that regulate microbial community responses

  3. Lysosomal membrane permeabilization: Carbon nanohorn-induced reactive oxygen species generation and toxicity by this neglected mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Mei, E-mail: happy_deercn@163.com [Nanotube Research Center, National Institute of Advanced Industrial Science and Technology 5-2, 1-1-1 Higashi, Tsukuba 305-8565 (Japan); Zhang, Minfang; Tahara, Yoshio; Chechetka, Svetlana; Miyako, Eijiro [Nanotube Research Center, National Institute of Advanced Industrial Science and Technology 5-2, 1-1-1 Higashi, Tsukuba 305-8565 (Japan); Iijima, Sumio [Nanotube Research Center, National Institute of Advanced Industrial Science and Technology 5-2, 1-1-1 Higashi, Tsukuba 305-8565 (Japan); Faculty of Science and Technology, Meijo University, 1-501 Shiogamaguchi, Tenpaku, Nagoya 468-8502 (Japan); Yudasaka, Masako, E-mail: m-yudasaka@aist.go.jp [Nanotube Research Center, National Institute of Advanced Industrial Science and Technology 5-2, 1-1-1 Higashi, Tsukuba 305-8565 (Japan)

    2014-10-01

    Understanding the molecular mechanisms responsible for the cytotoxic effects of carbon nanomaterials is important for their future biomedical applications. Carbon nanotubular materials induce the generation of reactive oxygen species (ROS), which causes cell death; however, the exact details of this process are still unclear. Here, we identify a mechanism of ROS generation that is involved in the apoptosis of RAW264.7 macrophages caused by excess uptake of carbon nanohorns (CNHs), a typical type of carbon nanotubule. CNH accumulated in the lysosomes, where they induced lysosomal membrane permeabilization (LMP) and the subsequent release of lysosomal proteases, such as cathepsins, which in turn caused mitochondrial dysfunction and triggered the generation of ROS in the mitochondria. The nicotinamide adenine dinucleotide phosphate oxidase was not directly involved in CNH-related ROS production, and the ROS generation cannot be regulated by mitochondrial electron transport chain. ROS fed back to amplify the mitochondrial dysfunction, leading to the subsequent activation of caspases and cell apoptosis. Carbon nanotubules commonly accumulate in the lysosomes after internalization in cells; however, lysosomal dysfunction has not attracted much attention in toxicity studies of these materials. These results suggest that LMP, a neglected mechanism, may be the primary reason for carbon nanotubule toxicity. - Highlights: • We clarify an apoptotic mechanism of RAW264.7 cells caused by carbon nanohorns. • In the meantime, the mechanism of CNH-induced ROS generation is identified. • LMP is the initial factor of CNH-induced ROS generation and cell death. • Cathepsins work as mediators that connect LMP and mitochondrial dysfunction.

  4. Diverse Colletotrichum species cause anthracnose of tea plants (Camellia sinensis (L.) O. Kuntze) in China.

    Science.gov (United States)

    Wang, Yu-Chun; Hao, Xin-Yuan; Wang, Lu; Bin Xiao; Wang, Xin-Chao; Yang, Ya-Jun

    2016-10-26

    Anthracnose caused by Colletotrichum is one of the most severe diseases that can afflict Camellia sinensis. However, research on the diversity and geographical distribution of Colletotrichum in China remain limited. In this study, 106 Colletotrichum isolates were collected from diseased leaves of Ca. sinensis cultivated in the 15 main tea production provinces in China. Multi-locus phylogenetic analysis coupled with morphological identification showed that the collected isolates belonged to 11 species, including 6 known species (C. camelliae, C. cliviae, C. fioriniae, C. fructicola, C. karstii, and C. siamense), 3 new record species (C. aenigma, C. endophytica, and C. truncatum), 1 novel species (C. wuxiense), and 1 indistinguishable strain, herein described as Colletotrichum sp. Of these species, C. camelliae and C. fructicola were the dominant species causing anthracnose in Ca. sinensis. In addition, our study provided further evidence that phylogenetic analysis using a combination of ApMat and GS sequences can be used to effectively resolve the taxonomic relationships within the C. gloeosporioides species complex. Finally, pathogenicity tests suggested that C. camelliae, C. aenigma, and C. endophytica are more invasive than other species after the inoculation of the leaves of Ca. sinensis.

  5. Modulation of Neutrophil Extracellular Trap and Reactive Oxygen Species Release by Periodontal Bacteria.

    Science.gov (United States)

    Hirschfeld, Josefine; White, Phillipa C; Milward, Michael R; Cooper, Paul R; Chapple, Iain L C

    2017-12-01

    Oral bacteria are the main trigger for the development of periodontitis, and some species are known to modulate neutrophil function. This study aimed to explore the release of neutrophil extracellular traps (NETs), associated antimicrobial proteins, and reactive oxygen species (ROS) in response to periodontal bacteria, as well as the underlying pathways. Isolated peripheral blood neutrophils were stimulated with 19 periodontal bacteria. NET and ROS release, as well as the expression of NET-bound antimicrobial proteins, elastase, myeloperoxidase, and cathepsin G, in response to these species was measured using fluorescence-based assays. NET and ROS release was monitored after the addition of NADP (NADPH) oxidase pathway modulators and inhibitors of Toll-like receptors (TLRs). Moreover, bacterial entrapment by NETs was visualized microscopically, and bacterial killing was assessed by bacterial culture. Certain microorganisms, e.g., Veillonella parvula and Streptococcus gordonii , stimulated higher levels of ROS and NET release than others. NETs were found to entrap, but not kill, all periodontal bacteria tested. NADPH oxidase pathway modulators decreased ROS production but not NET production in response to the bacteria. Interestingly, TLR inhibitors did not impact ROS and NET release. These data suggest that the variability in the neutrophil response toward different bacteria may contribute to the pathogenesis of periodontal diseases by mechanisms such as bacterial avoidance of host responses and activation of neutrophils. Moreover, our results indicate that bacterium-stimulated NET release may arise in part via NADPH oxidase-independent mechanisms. The role of TLR signaling in bacterium-induced ROS and NET release needs to be further elucidated. Copyright © 2017 American Society for Microbiology.

  6. Comparison of Mitochondrial Reactive Oxygen Species Production of Ectothermic and Endothermic Fish Muscle

    Directory of Open Access Journals (Sweden)

    Lilian Wiens

    2017-09-01

    Full Text Available Recently we demonstrated that the capacity of isolated muscle mitochondria to produce reactive oxygen species, measured as H2O2 efflux, is temperature-sensitive in isolated muscle mitochondria of ectothermic fish and the rat, a representative endothermic mammal. However, at physiological temperatures (15° and 37°C for the fish and rat, respectively, the fraction of total mitochondrial electron flux that generated H2O2, the fractional electron leak (FEL, was far lower in the rat than in fish. Those results suggested that the elevated body temperatures associated with endothermy may lead to a compensatory decrease in mitochondrial ROS production relative to respiratory capacity. To test this hypothesis we compare slow twitch (red muscle mitochondria from the endothermic Pacific bluefin tuna (Thunnus orientalis with mitochondria from three ectothermic fishes [rainbow trout (Oncorhynchus mykiss, common carp (Cyprinus carpio, and the lake sturgeon (Acipenser fulvescens] and the rat. At a common assay temperature (25°C rates of mitochondrial respiration and H2O2 efflux were similar in tuna and the other fishes. The thermal sensitivity of fish mitochondria was similar irrespective of ectothermy or endothermy. Comparing tuna to the rat at a common temperature, respiration rates were similar, or lower depending on mitochondrial substrates. FEL was not different across fish species at a common assay temperature (25°C but was markedly higher in fishes than in rat. Overall, endothermy and warming of Pacific Bluefin tuna red muscle may increase the potential for ROS production by muscle mitochondria but the evolution of endothermy in this species is not necessarily associated with a compensatory reduction of ROS production relative to the respiratory capacity of mitochondria.

  7. Determination of reactive oxygen species from ZnO micro-nano structures with shape-dependent photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    He, Weiwei; Zhao, Hongxiao; Jia, Huimin [Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Yin, Jun-Jie [Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, MD 20740 (United States); Zheng, Zhi, E-mail: zhengzhi99999@gmail.com [Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China)

    2014-05-01

    Graphical abstract: ZnO micro/nano structures with shape dependent photocatalytic activity were prepared by hydrothermal reaction. The generations of hydroxyl radical, superoxide and singlet oxygen from irradiated ZnO were identified precisely by electron spin resonance spectroscopy. The type of reactive oxygen species was determined by band gap structure of ZnO. - Highlights: • ZnO micro/nano structures with different morphologies were prepared by solvothermal reaction. • Multi-pod like ZnO structures exhibited superior photocatalytic activity. • The generations of hydroxyl radical, superoxide and singlet oxygen from irradiated ZnO were characterized precisely by electron spin resonance spectroscopy. • The type of reactive oxygen species was determined by band gap structure of ZnO. - Abstract: ZnO micro/nano structures with different morphologies have been prepared by the changing solvents used during their synthesis by solvothermal reaction. Three typical shapes of ZnO structures including hexagonal, bell bottom like and multi-pod formed and were characterized by scanning electron microscopy and X-ray diffraction. Multi pod like ZnO structures exhibited the highest photocatalytic activity toward degradation of methyl orange. Using electron spin resonance spectroscopy coupled with spin trapping techniques, we demonstrate an effective way to identify precisely the generation of hydroxyl radicals, superoxide and singlet oxygen from the irradiated ZnO multi pod structures. The type of reactive oxygen species formed was predictable from the band gap structure of ZnO. These results indicate that the shape of micro-nano structures significantly affects the photocatalytic activity of ZnO, and demonstrate the value of electron spin resonance spectroscopy for characterizing the type of reactive oxygen species formed during photoexcitation of semiconductors.

  8. Determination of reactive oxygen species from ZnO micro-nano structures with shape-dependent photocatalytic activity

    International Nuclear Information System (INIS)

    He, Weiwei; Zhao, Hongxiao; Jia, Huimin; Yin, Jun-Jie; Zheng, Zhi

    2014-01-01

    Graphical abstract: ZnO micro/nano structures with shape dependent photocatalytic activity were prepared by hydrothermal reaction. The generations of hydroxyl radical, superoxide and singlet oxygen from irradiated ZnO were identified precisely by electron spin resonance spectroscopy. The type of reactive oxygen species was determined by band gap structure of ZnO. - Highlights: • ZnO micro/nano structures with different morphologies were prepared by solvothermal reaction. • Multi-pod like ZnO structures exhibited superior photocatalytic activity. • The generations of hydroxyl radical, superoxide and singlet oxygen from irradiated ZnO were characterized precisely by electron spin resonance spectroscopy. • The type of reactive oxygen species was determined by band gap structure of ZnO. - Abstract: ZnO micro/nano structures with different morphologies have been prepared by the changing solvents used during their synthesis by solvothermal reaction. Three typical shapes of ZnO structures including hexagonal, bell bottom like and multi-pod formed and were characterized by scanning electron microscopy and X-ray diffraction. Multi pod like ZnO structures exhibited the highest photocatalytic activity toward degradation of methyl orange. Using electron spin resonance spectroscopy coupled with spin trapping techniques, we demonstrate an effective way to identify precisely the generation of hydroxyl radicals, superoxide and singlet oxygen from the irradiated ZnO multi pod structures. The type of reactive oxygen species formed was predictable from the band gap structure of ZnO. These results indicate that the shape of micro-nano structures significantly affects the photocatalytic activity of ZnO, and demonstrate the value of electron spin resonance spectroscopy for characterizing the type of reactive oxygen species formed during photoexcitation of semiconductors

  9. Inverse correlation between reactive oxygen species in unwashed semen and sperm motion parameters as measured by a computer-assisted semen analyzer.

    Science.gov (United States)

    Takeshima, Teppei; Yumura, Yasushi; Yasuda, Kengo; Sanjo, Hiroyuki; Kuroda, Shinnosuke; Yamanaka, Hiroyuki; Iwasaki, Akira

    2017-01-01

    This study investigated the correlation between sperm motion parameters obtained by a computer-assisted semen analyzer and levels of reactive oxygen species in unwashed semen. In total, 847 patients, except for azoospermic patients were investigated. At the time of each patient's first consultation, semen parameters were measured using SMAS™ or CellSoft 3000™, and production of reactive oxygen species was measured using a computer-driven LKB Wallac Luminometer 1251 Analyzer. The patients were divided into two groups: reactive oxygen species - positive and negative. The semen parameters within each group were measured using one of the two computer-assisted semen analyzer systems and then compared. Correlations between reactive oxygen species levels and sperm motion parameters in semen from the reactive oxygen species - positive group were also investigated. Reactive oxygen species were detected in semen samples of 282 cases (33.3%). Sperm concentration (P semen damage sperm concentration, motility, and other sperm motion parameters.

  10. Covariance of oxygen and hydrogen isotopic compositions in plant water: species effects

    International Nuclear Information System (INIS)

    Cooper, L.W.; DeNiro, M.J.

    1989-01-01

    Leaf water becomes enriched in the heavy isotopes of oxygen and hydrogen during evapotranspiration. The magnitude of the enrichment has been shown to be influenced by temperature and humidity, but the effects of species—specific factors on leaf water enrichment of D and 18 O have not been studied for different plants growing together. Accordingly, to learn whether leaf water enrichment patterns and processes for D and 18 O are different for individual species growing under the same environmental conditions we tested the proposal that leaf waters in plants with crassulacean acid metabolism (CAM) show higher slopes (m in the leaf water equation °D = m ° 18 O + b) than in C 3 plants. We determined the relationships between the stable hydrogen (°D) and oxygen (° 18 O) isotope ratios of leaf waters collected during the diurnal cycle of evapotranspiration for Yucca schidigera, Ephedra aspera, Agave deserti, Prunus ilicifolia, Yucca whipplei, Heteromeles arbutifolia, Dyckia fosteriana, Simmondsia chinensis, and Encelia farinosa growing at two sites in southern California. Slopes (m in the above leaf water equation) ranged from 1.50 to 3.21, compared to °8 for meteoric water, but differences in slope could not be attributed to carboxylation pathway (CAM vs. C 3 ) nor climate (coastal California vs. Sonoran Desert). Higher slopes were correlated with greater overall ranges of leaf water enrichment of D and 18 O. Water in plants with higher slopes also differed most from unaltered meteoric water. Leaf water isotope ratios in plants with lower slopes were better correlated with temperature and humidity. The findings indicate that m in the aforementioned equation is related to the overall residence time for water in the leaf and proportions of water subjected to repeated evapotranspiration enrichments of heavy isotopes

  11. Release of proteins from intact chloroplasts induced by reactive oxygen species during biotic and abiotic stress.

    Science.gov (United States)

    Kwon, Kwang-Chul; Verma, Dheeraj; Jin, Shuangxia; Singh, Nameirakpam D; Daniell, Henry

    2013-01-01

    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

  12. Release of proteins from intact chloroplasts induced by reactive oxygen species during biotic and abiotic stress.

    Directory of Open Access Journals (Sweden)

    Kwang-Chul Kwon

    Full Text Available 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

  13. Catheter-related bacteraemia and infective endocarditis caused by Kocuria species.

    Science.gov (United States)

    Lai, C C; Wang, J Y; Lin, S H; Tan, C K; Wang, C Y; Liao, C H; Chou, C H; Huang, Y T; Lin, H I; Hsueh, P R

    2011-02-01

    We describe five patients with positive blood culture for Kocuria species. Three patients had catheter-related bacteraemia and one had infective endocarditis caused by Kocuria kristinae, and one had a K. marina isolate, which was considered to be a contaminant. Identification of the isolates was further confirmed by 16S rRNA gene sequence analysis. In conclusion, Kocuria species are an unusual cause of infection in immunocompromised patients. Accurate identification with molecular methods is imperative for the diagnosis of these unusual pathogens. © 2010 The Authors. Journal Compilation © 2010 European Society of Clinical Microbiology and Infectious Diseases.

  14. Species specificity of resistance to oxygen diffusion in thin cuticular membranes from amphibious plants

    DEFF Research Database (Denmark)

    Frost-Christensen, Henning; Jørgensen, Lise Bolt; Floto, Franz

    2003-01-01

    oxygen, diffusion, cuticula, amphibious plants, Hygrophila, Berula, Lobelia, Mentha, Potamogeton, Veronica, aquatic plants, submerged plants......oxygen, diffusion, cuticula, amphibious plants, Hygrophila, Berula, Lobelia, Mentha, Potamogeton, Veronica, aquatic plants, submerged plants...

  15. Mobile phone radiation induces reactive oxygen species production and DNA damage in human spermatozoa in vitro.

    Directory of Open Access Journals (Sweden)

    Geoffry N De Iuliis

    Full Text Available 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

  16. The Synergistic Effect of Proteins and Reactive Oxygen Species on Electrochemical Behaviour of 316L Stainless Steel for Biomedical Applications

    Science.gov (United States)

    Simionescu, N.; Benea, L.; Dumitrascu, V. M.

    2018-06-01

    The stainless steels, especially 316L type is the most used metallic biomaterials for biomedical applications due to their good biocompatibility, low price, excellent corrosion resistance, availability, easy processing and high strength. Due to these favorable properties 316L stainless steel has become the most attractive biomaterial for dental implants, stents and orthopedic implants. However an implant material in the human body is exposed to an action effect of other molecules, including proteins (such as albumin) and reactive oxygen species (such as hydrogen peroxide - H2O2 ) produced by bacteria and immune cells. In the literature there are few studies to follow the effect of proteins and reactive oxygen species on 316L stainless steel used as implant material and are still unclear. The degree of corrosion resistance is the first criterion in the use of a metallic biomaterial in the oral or body environment. The aim of this research work is to investigate the influence of proteins (albumin) and reactive oxygen species (H2O2 ) in combination, taking into account the synergistic effect of these two factors on 316L stainless steel. Albumin is present in the body near implants and reactive oxygen species could appear in inflammatory processes as well. The study shows that the presence of albumin and reactive species influences the corrosion resistance of 316L stainless steel in biological solutions. In this research work the corrosion behavior of 316L stainless steel is analyzed by electrochemical methods such as: open circuit potential (OCP), Electrochemical Impedance Spectroscopy (EIS). It was found that, the electrochemical results are in a good agreement with micro photographs taken before and after corrosion assays. The albumin and reactive oxygen species have influence on 316L stainless steel behavior.

  17. Fast Oxidation Processes in a Naturally Reduced Aquifer Zone Caused by Dissolved Oxygen

    Science.gov (United States)

    Davis, J. A.; Jemison, N. E.; Williams, K. H.; Hobson, C.; Bush, R. P.

    2014-12-01

    The occurrence of naturally reduced zones is quite common in alluvial aquifers in the western U.S.A. due to the burial of woody debris in flood plains. The naturally reduced zones are heterogeneously dispersed in such aquifers and are characterized by high concentrations of organic carbon and reduced phases, including iron sulfides and reduced forms of metals, including uranium(IV). The persistence of high concentrations of dissolved uranium(VI) at uranium-contaminated aquifers on the Colorado Plateau has been attributed to slow oxidation of insoluble uranium(IV) mineral phases that are found in association with these natural reducing zones, although there is little understanding of the relative importance of various potential oxidants. Three field experiments were conducted within an alluvial aquifer adjacent to the Colorado River near Rifle, CO wherein groundwater associated with naturally reduced zones was pumped into a gas-impermeable tank, mixed with a conservative tracer (Br-), bubbled with a gas phase composed of 97% O2 and 3% CO2, and then returned to the subsurface in the same well from which it was withdrawn. Within minutes of re-injection of the oxygenated groundwater, dissolved uranium(VI) concentrations increased from less than 1 μM to greater than 2.5 μM, demonstrating that oxygen can be an important oxidant for uranium in these field systems if supplied to the naturally reduced zones. Small concentrations of nitrate were also observed in the previously nitrate-free groundwater, and Fe(II) decreased to the detection limit. These results contrast with other laboratory and field results in which oxygen was introduced to systems containing high concentrations of mackinawite (FeS) rather than the more crystalline iron sulfides found in aged, naturally reduced zones. The flux of oxygen to the naturally reduced zones in the alluvial aquifers occurs mainly through interactions between groundwater and gas phases at the water table, and seasonal variations

  18. Sirtuin-3 (Sirt3) regulates skeletal muscle metabolism and insulin signaling via altered mitochondrial oxidation and reactive oxygen species production

    DEFF Research Database (Denmark)

    Jing, Enxuan; Emanuelli, Brice; Hirschey, Matthew D

    2011-01-01

    Sirt3 is a member of the sirtuin family of protein deacetylases that is localized in mitochondria and regulates mitochondrial function. Sirt3 expression in skeletal muscle is decreased in models of type 1 and type 2 diabetes and regulated by feeding, fasting, and caloric restriction. Sirt3 knockout...... mice exhibit decreased oxygen consumption and develop oxidative stress in skeletal muscle, leading to JNK activation and impaired insulin signaling. This effect is mimicked by knockdown of Sirt3 in cultured myoblasts, which exhibit reduced mitochondrial oxidation, increased reactive oxygen species......, activation of JNK, increased serine and decreased tyrosine phosphorylation of IRS-1, and decreased insulin signaling. Thus, Sirt3 plays an important role in diabetes through regulation of mitochondrial oxidation, reactive oxygen species production, and insulin resistance in skeletal muscle....

  19. Risk factors for fatal candidemia caused by Candida albicans and non-albicans Candida species

    Directory of Open Access Journals (Sweden)

    Tang Ran-Bin

    2005-04-01

    Full Text Available Abstract Background Invasive fungal infections, such as candidemia, caused by Candida species have been increasing. Candidemia is not only associated with a high mortality (30% to 40% but also extends the length of hospital stay and increases the costs of medical care. Sepsis caused by Candida species is clinically indistinguishable from bacterial infections. Although, the clinical presentations of the patients with candidemia caused by Candida albicans and non-albicans Candida species (NAC are indistinguishable, the susceptibilities to antifungal agents of these species are different. In this study, we attempted to identify the risk factors for candidemia caused by C. albicans and NAC in the hope that this may guide initial empiric therapy. Methods A retrospective chart review was conducted during 1996 to 1999 at the Veterans General Hospital-Taipei. Results There were 130 fatal cases of candidemia, including 68 patients with C. albicans and 62 with NAC. Candidemia was the most likely cause of death in 55 of the 130 patients (42.3 %. There was no significant difference in the distribution of Candida species between those died of candidemia and those died of underlying conditions. Patients who had one of the following conditions were more likely to have C. albicans, age ≧ 65 years, immunosuppression accounted to prior use of steroids, leukocytosis, in the intensive care unit (ICU, and intravascular and urinary catheters. Patients who had undergone cancer chemotherapy often appeared less critically ill and were more likely to have NAC. Conclusion Clinical and epidemiological differences in the risk factors between candidemia caused by C. albicans and NAC may provide helpful clues to initiate empiric therapy for patients infected with C. albicans versus NAC.

  20. Risk factors for fatal candidemia caused by Candida albicans and non-albicans Candida species

    Science.gov (United States)

    Cheng, Ming-Fang; Yang, Yun-Liang; Yao, Tzy-Jyun; Lin, Chin-Yu; Liu, Jih-Shin; Tang, Ran-Bin; Yu, Kwok-Woon; Fan, Yu-Hua; Hsieh, Kai-Sheng; Ho, Monto; Lo, Hsiu-Jung

    2005-01-01

    Background Invasive fungal infections, such as candidemia, caused by Candida species have been increasing. Candidemia is not only associated with a high mortality (30% to 40%) but also extends the length of hospital stay and increases the costs of medical care. Sepsis caused by Candida species is clinically indistinguishable from bacterial infections. Although, the clinical presentations of the patients with candidemia caused by Candida albicans and non-albicans Candida species (NAC) are indistinguishable, the susceptibilities to antifungal agents of these species are different. In this study, we attempted to identify the risk factors for candidemia caused by C. albicans and NAC in the hope that this may guide initial empiric therapy. Methods A retrospective chart review was conducted during 1996 to 1999 at the Veterans General Hospital-Taipei. Results There were 130 fatal cases of candidemia, including 68 patients with C. albicans and 62 with NAC. Candidemia was the most likely cause of death in 55 of the 130 patients (42.3 %). There was no significant difference in the distribution of Candida species between those died of candidemia and those died of underlying conditions. Patients who had one of the following conditions were more likely to have C. albicans, age ≧ 65 years, immunosuppression accounted to prior use of steroids, leukocytosis, in the intensive care unit (ICU), and intravascular and urinary catheters. Patients who had undergone cancer chemotherapy often appeared less critically ill and were more likely to have NAC. Conclusion Clinical and epidemiological differences in the risk factors between candidemia caused by C. albicans and NAC may provide helpful clues to initiate empiric therapy for patients infected with C. albicans versus NAC. PMID:15813977

  1. The role of UCP 1 in production of reactive oxygen species by mitochondria isolated from brown adipose tissue

    Czech Academy of Sciences Publication Activity Database

    Dlasková, Andrea; Clarke, K.J.; Porter, R. K.

    2010-01-01

    Roč. 1797, č. 8 (2010), s. 1470-1476 ISSN 0005-2728 Institutional research plan: CEZ:AV0Z50110509 Keywords : Mitochondria * Reactive oxygen species * Uncoupling protein 1 Subject RIV: ED - Physiology Impact factor: 5.132, year: 2010

  2. Intracellular expression of reactive oxygen species-generating NADPH oxidase NOX4 in normal and cancer thyroid tissues

    NARCIS (Netherlands)

    Weyemi, Urbain; Caillou, Bernard; Talbot, Monique; Ameziane-El-Hassani, Rabii; Lacroix, Ludovic; Lagent-Chevallier, Odile; Al Ghuzlan, Abir; Roos, Dirk; Bidart, Jean-Michel; Virion, Alain; Schlumberger, Martin; Dupuy, Corinne

    2010-01-01

    NADPH oxidase 4 (NOX4) belongs to the NOX family that generates reactive oxygen species (ROS). Function and tissue distribution of NOX4 have not yet been entirely clarified. To date, in the thyroid gland, only DUOX1/2 NOX systems have been described. NOX4 mRNA expression, as shown by real-time PCR,

  3. Induction of molecular endpoints by reactive oxygen species in human lung cells predicted by physical chemical properties of engineered nanoparticles

    Science.gov (United States)

    A series of six titanium dioxide and two cerium oxide engineered nanomaterials were assessed for their ability to induce cytotoxicity, reactive oxygen species (ROS), and various types of DNA and protein damage in human respiratory BEAS-2B cells exposed in vitro for 72 hours at se...

  4. Surgery-induced reactive oxygen species enhance colon carcinoma cell binding by disrupting the liver endothelial cell lining

    NARCIS (Netherlands)

    Gül, Nuray; Bögels, Marijn; Grewal, Simran; van der Meer, Anne Jan; Rojas, Lucy Baldeon; Fluitsma, Donna M.; van den Tol, M. Petrousjka; Hoeben, Kees A.; van Marle, Jan; de Vries, Helga E.; Beelen, Robert H. J.; van Egmond, Marjolein

    2011-01-01

    Resection of primary colorectal cancer is associated with enhanced risk of development of liver metastases. It was previously demonstrated that surgery initiated an early inflammatory response resulting in elevated tumour cell adhesion in the liver. Because reactive oxygen species (ROS) are shown to

  5. Surgery-induced reactive oxygen species enhance colon carcinoma cell binding by disrupting the liver endothelial cell lining

    NARCIS (Netherlands)

    Gül, N.; Bögels, M.; Grewal, S.; van der Meer, A.J.; Rojas, L.B.; Fluitsma, D.M.; van den Tol, M.P.; Hoeben, K.A.; van Marle, J.; de Vries, H.E.; Beelen, R.H.J.; van Egmond, M.

    2011-01-01

    Objective: Resection of primary colorectal cancer is associated with enhanced risk of development of liver metastases. It was previously demonstrated that surgery initiated an early inflammatory response resulting in elevated tumour cell adhesion in the liver. Because reactive oxygen species (ROS)

  6. Surgery-induced reactive oxygen species enhance colon carcinoma cell binding by disrupting the liver endothelial cell lining

    NARCIS (Netherlands)

    Gul, N.; Bogels, M.; Grewal, S.; van der Meer, A.J.; Rojas, L.B.; Fluitsma, D.M.; van den Tol, M.P.; Hoeben, K.A.; van Marle, J.; de Vries, H.E.; Beelen, R.H.J.; van Egmond, M.

    2011-01-01

    Objective Resection of primary colorectal cancer is associated with enhanced risk of development of liver metastases. It was previously demonstrated that surgery initiated an early inflammatory response resulting in elevated tumour cell adhesion in the liver. Because reactive oxygen species (ROS)

  7. Role of histamine receptors in the effects of histamine on the production of reactive oxygen species by whole blood phagocytes

    Czech Academy of Sciences Publication Activity Database

    Vašíček, Ondřej; Lojek, Antonín; Jančinová, V.; Nosál, R.; Číž, Milan

    2014-01-01

    Roč. 100, č. 1 (2014), s. 67-72 ISSN 0024-3205 R&D Projects: GA MŠk(CZ) LD11010 Institutional support: RVO:68081707 Keywords : Histamine * Histamine receptors * Reactive oxygen species Subject RIV: BO - Biophysics Impact factor: 2.702, year: 2014

  8. Oxygen isotope fractionations across individual leaf carbohydrates in grass and tree species.

    Science.gov (United States)

    Lehmann, Marco M; Gamarra, Bruno; Kahmen, Ansgar; Siegwolf, Rolf T W; Saurer, Matthias

    2017-08-01

    Almost no δ 18 O data are available for leaf carbohydrates, leaving a gap in the understanding of the δ 18 O relationship between leaf water and cellulose. We measured δ 18 O values of bulk leaf water (δ 18 O LW ) and individual leaf carbohydrates (e.g. fructose, glucose and sucrose) in grass and tree species and δ 18 O of leaf cellulose in grasses. The grasses were grown under two relative humidity (rH) conditions. Sucrose was generally 18 O-enriched compared with hexoses across all species with an apparent biosynthetic fractionation factor (ε bio ) of more than 27‰ relative to δ 18 O LW , which might be explained by isotopic leaf water and sucrose synthesis gradients. δ 18 O LW and δ 18 O values of carbohydrates and cellulose in grasses were strongly related, indicating that the leaf water signal in carbohydrates was transferred to cellulose (ε bio  = 25.1‰). Interestingly, damping factor p ex p x , which reflects oxygen isotope exchange with less enriched water during cellulose synthesis, responded to rH conditions if modelled from δ 18 O LW but not if modelled directly from δ 18 O of individual carbohydrates. We conclude that δ 18 O LW is not always a good substitute for δ 18 O of synthesis water due to isotopic leaf water gradients. Thus, compound-specific δ 18 O analyses of individual carbohydrates are helpful to better constrain (post-)photosynthetic isotope fractionation processes in plants. © 2017 John Wiley & Sons Ltd.

  9. Pentose Phosphate Shunt Modulates Reactive Oxygen Species and Nitric Oxide Production Controlling Trypanosoma cruzi in Macrophages

    Directory of Open Access Journals (Sweden)

    Sue-jie Koo

    2018-02-01

    Full Text Available Metabolism provides substrates for reactive oxygen species (ROS and nitric oxide (NO generation, which are a part of the macrophage (Mφ anti-microbial response. Mφs infected with Trypanosoma cruzi (Tc produce insufficient levels of oxidative species and lower levels of glycolysis compared to classical Mφs. How Mφs fail to elicit a potent ROS/NO response during infection and its link to glycolysis is unknown. Herein, we evaluated for ROS, NO, and cytokine production in the presence of metabolic modulators of glycolysis and the Krebs cycle. Metabolic status was analyzed by Seahorse Flux Analyzer and mass spectrometry and validated by RNAi. Tc infection of RAW264.7 or bone marrow-derived Mφs elicited a substantial increase in peroxisome proliferator-activated receptor (PPAR-α expression and pro-inflammatory cytokine release, and moderate levels of ROS/NO by 18 h. Interferon (IFN-γ addition enhanced the Tc-induced ROS/NO release and shut down mitochondrial respiration to the levels noted in classical Mφs. Inhibition of PPAR-α attenuated the ROS/NO response and was insufficient for complete metabolic shift. Deprivation of glucose and inhibition of pyruvate transport showed that Krebs cycle and glycolysis support ROS/NO generation in Tc + IFN-γ stimulated Mφs. Metabolic profiling and RNAi studies showed that glycolysis-pentose phosphate pathway (PPP at 6-phosphogluconate dehydrogenase was essential for ROS/NO response and control of parasite replication in Mφ. We conclude that IFN-γ, but not inhibition of PPAR-α, supports metabolic upregulation of glycolytic-PPP for eliciting potent ROS/NO response in Tc-infected Mφs. Chemical analogs enhancing the glucose-PPP will be beneficial in controlling Tc replication and dissemination by Mφs.

  10. Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species.

    Science.gov (United States)

    Arjunan, Krishna Priya; Friedman, Gary; Fridman, Alexander; Clyne, Alisa Morss

    2012-01-07

    Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), has recently emerged as an efficient tool in medical applications including blood coagulation, sterilization and malignant cell apoptosis. Liquids and porcine aortic endothelial cells were treated with a non-thermal dielectric barrier discharge plasma in vitro. Plasma treatment of phosphate-buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration observed in serum-free medium compared with PBS. Species concentration inside cells peaked 1 h after treatment, followed by a decrease 3 h post treatment. Endothelial cells treated with a plasma dose of 4.2 J cm(-2) had 1.7 times more cells than untreated samples 5 days after plasma treatment. The 4.2 J cm(-2) plasma dose increased two-dimensional migration distance by 40 per cent compared with untreated control, while the number of cells that migrated through a three-dimensional collagen gel increased by 15 per cent. Tube formation was also enhanced by plasma treatment, with tube lengths in plasma-treated samples measuring 2.6 times longer than control samples. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers abrogated these angiogenic effects. These data indicate that plasma enhanced proliferation, migration and tube formation is due to FGF-2 release induced by plasma-produced ROS. Non-thermal plasma may be used as a potential tool for applying ROS in precise doses to enhance vascularization.

  11. Mitochondrial Reactive Oxygen Species and Kidney Hypoxia in the Development of Diabetic Nephropathy.

    Science.gov (United States)

    Schiffer, Tomas A; Friederich-Persson, Malou

    2017-01-01

    The underlying mechanisms in the development of diabetic nephropathy are currently unclear and likely consist of a series of dynamic events from the early to late stages of the disease. Diabetic nephropathy is currently without curative treatments and it is acknowledged that even the earliest clinical manifestation of nephropathy is preceded by an established morphological renal injury that is in turn preceded by functional and metabolic alterations. An early manifestation of the diabetic kidney is the development of kidney hypoxia that has been acknowledged as a common pathway to nephropathy. There have been reports of altered mitochondrial function in the diabetic kidney such as altered mitophagy, mitochondrial dynamics, uncoupling, and cellular signaling through hypoxia inducible factors and AMP-kinase. These factors are also likely to be intertwined in a complex manner. In this review, we discuss how these pathways are connected to mitochondrial production of reactive oxygen species (ROS) and how they may relate to the development of kidney hypoxia in diabetic nephropathy. From available literature, it is evident that early correction and/or prevention of mitochondrial dysfunction may be pivotal in the prevention and treatment of diabetic nephropathy.

  12. Hydrolase stabilization via entanglement in poly(propylene sulfide) nanoparticles: stability towards reactive oxygen species

    International Nuclear Information System (INIS)

    Allen, Brett L; Johnson, Jermaine D; Walker, Jeremy P

    2012-01-01

    In the advancement of green syntheses and sustainable reactions, enzymatic biocatalysis offers extremely high reaction rates and selectivity that goes far beyond the reach of chemical catalysts; however, these enzymes suffer from typical environmental constraints, e.g. operational temperature, pH and tolerance to oxidative environments. A common hydrolase enzyme, diisopropylfluorophosphatase (DFPase, EC 3.1.8.2), has demonstrated a pronounced efficacy for the hydrolysis of a variety of substrates for potential toxin remediation, but suffers from the aforementioned limitations. As a means to enhance DFPase’s stability in oxidative environments, enzymatic covalent immobilization within the polymeric matrix of poly(propylene sulfide) (PPS) nanoparticles was performed. By modifying the enzyme’s exposed lysine residues via thiolation, DFPase is utilized as a comonomer/crosslinker in a mild emulsion polymerization. The resultant polymeric polysulfide shell acts as a ‘sacrificial barrier’ by first oxidizing to polysulfoxides and polysulfones, rendering DFPase in an active state. DFPase–PPS nanoparticles thus retain activity upon exposure to as high as 50 parts per million (ppm) of hypochlorous acid (HOCl), while native DFPase is observed as inactive at 500 parts per billion (ppb). This trend is also confirmed by enzyme-generated (chloroperoxidase (CPO), EC 1.11.1.10) reactive oxygen species (ROS) including both HOCl (3 ppm) and ClO 2 (100 ppm). (paper)

  13. Antifungal Effect of Arabidopsis SGT1 Proteins via Mitochondrial Reactive Oxygen Species.

    Science.gov (United States)

    Park, Seong-Cheol; Cheong, Mi Sun; Kim, Eun-Ji; Kim, Jin Hyo; Chi, Yong Hun; Jang, Mi-Kyeong

    2017-09-27

    The highly conserved SGT1 (suppressor of the G2 alleles of skp1) proteins from Arabidopsis are known to contribute to plant resistance to pathogens. While SGT1 proteins respond to fungal pathogens, their antifungal activity is not reported and the mechanism for this inhibition is not well understood. Therefore, recombinant Arabidopsis SGT1 proteins were cloned, expressed, and purified to evaluate their antifungal activity, resulting in their potent inhibition of pathogen growth. Dye-labeled proteins are localized to the cytosol of Candida albicans cells without the disruption of the cell membrane. Moreover, we showed that entry of the proteins into C. albicans cells resulted in the accumulation of reactive oxygen species (ROS) and cell death via altered mitochondrial potential. Morphological changes of C. albicans cells in the presence of proteins were visualized by scanning electron microscopy. Our data suggest that AtSGT1 proteins play a critical role in plant resistance to pathogenic fungal infection and they can be classified to a new plant antifungal protein.

  14. Reactive oxygen species acts as executor in radiation enhancement and autophagy inducing by AgNPs.

    Science.gov (United States)

    Wu, Hao; Lin, Jun; Liu, Peidang; Huang, Zhihai; Zhao, Peng; Jin, Haizhen; Ma, Jun; Wen, Longping; Gu, Ning

    2016-09-01

    Malignant glioma is one of the most common intracranial tumor with a dismal prognosis. The radiosensitizing effect of silver nanoparticles (AgNPs) on glioma both in vitro and in vivo were demonstrated in the previous studies of our group. However, the underlying mechanism is still unclear. In this present study, the use of antioxidants is employed for the regulating of reactive oxygen species (ROS) in U251 cells treated with various agents, and the results shows that ROS played an essential role in the autophagy inducing and radiosensitization effect of AgNPs. Moreover, the inhibition of protective autophagy with 3-MA is another way to increase ROS, resulting in the increasing of cell death and apoptosis. Taken together, understanding the relationship between the elevated ROS and autophagy and the effect of ROS should be useful to the clinical applications of AgNPs. These findings could potentially be exploited for new therapeutic strategies in glioma radiotherapy. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Extracellular ultrathin fibers sensitive to intracellular reactive oxygen species: Formation of intercellular membrane bridges

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Se-Hui; Park, Jin-Young; Joo, Jung-Hoon; Kim, Young-Myeong; Ha, Kwon-Soo, E-mail: ksha@kangwon.ac.kr

    2011-07-15

    Membrane bridges are key cellular structures involved in intercellular communication; however, dynamics for their formation are not well understood. We demonstrated the formation and regulation of novel extracellular ultrathin fibers in NIH3T3 cells using confocal and atomic force microscopy. At adjacent regions of neighboring cells, phorbol 12-myristate 13-acetate (PMA) and glucose oxidase induced ultrathin fiber formation, which was prevented by Trolox, a reactive oxygen species (ROS) scavenger. The height of ROS-sensitive ultrathin fibers ranged from 2 to 4 nm. PMA-induced formation of ultrathin fibers was inhibited by cytochalasin D, but not by Taxol or colchicine, indicating that ultrathin fibers mainly comprise microfilaments. PMA-induced ultrathin fibers underwent dynamic structural changes, resulting in formation of intercellular membrane bridges. Thus, these fibers are formed by a mechanism(s) involving ROS and involved in formation of intercellular membrane bridges. Furthermore, ultrastructural imaging of ultrathin fibers may contribute to understanding the diverse mechanisms of cell-to-cell communication and the intercellular transfer of biomolecules, including proteins and cell organelles.

  16. Friend or foe? Reactive oxygen species production, scavenging and signaling in plant response to environmental stresses.

    Science.gov (United States)

    Czarnocka, Weronika; Karpiński, Stanisław

    2018-01-10

    In the natural environment, plants are exposed to a variety of biotic and abiotic stress conditions that trigger rapid changes in the production and scavenging of reactive oxygen species (ROS). The production and scavenging of ROS is compartmentalized, which means that, depending on stimuli type, they can be generated and eliminated in different cellular compartments such as the apoplast, plasma membrane, chloroplasts, mitochondria, peroxisomes, and endoplasmic reticulum. Although the accumulation of ROS is generally harmful to cells, ROS play an important role in signaling pathways that regulate acclimatory and defense responses in plants, such as systemic acquired acclimation (SAA) and systemic acquired resistance (SAR). However, high accumulations of ROS can also trigger redox homeostasis disturbance which can lead to cell death, and in consequence, to a limitation in biomass and yield production. Different ROS have various half-lifetimes and degrees of reactivity toward molecular components such as lipids, proteins, and nucleic acids. Thus, they play different roles in intra- and extra-cellular signaling. Despite their possible damaging effect, ROS should mainly be considered as signaling molecules that regulate local and systemic acclimatory and defense responses. Over the past two decades it has been proven that ROS together with non-photochemical quenching (NPQ), hormones, Ca 2+ waves, and electrical signals are the main players in SAA and SAR, two physiological processes essential for plant survival and productivity in unfavorable conditions. Copyright © 2018. Published by Elsevier Inc.

  17. Controllable generation of reactive oxygen species by femtosecond-laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Wei; He, Hao, E-mail: haohe@tju.edu.cn; Wang, Yintao; Wang, Yisen; Hu, Minglie; Wang, Chingyue [Ultrafast Laser Laboratory, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin (China)

    2014-02-24

    Femtosecond lasers have been advancing Biophotonics research in the past two decades with multiphoton microscopy, microsurgery, and photodynamic therapy. Nevertheless, laser irradiation is identified to bring photodamage to cells via reactive oxygen species (ROS) generation with unclear mechanism. Meanwhile, currently in biological researches, there is no effective method to provide controllable ROS production precisely, which originally is leaked from mitochondria during respiration and plays a key role in a lot of important cellular processes and cellular signaling pathways. In this study, we show the process of how the tightly focused femtosecond-laser induces ROS generation solely in mitochondria at the very beginning and then release to cytosol if the stimulus is intense enough. At certain weak power levels, the laser pulses induce merely moderate Ca{sup 2+} release but this is necessary for the laser to generate ROS in mitochondria. Cellular original ROS are also involved with a small contribution. When the power is above a threshold, ROS are then released to cytosol, indicating photodamage overwhelming cellular repair ability. The mechanisms in those two cases are quite different. Those results clarify parts of the mechanism in laser-induced ROS generation. Hence, it is possible to further this optical scheme to provide controllable ROS generation for ROS-related biological researches including mitochondrial diseases and aging.

  18. Development of nitroxide radicals–containing polymer for scavenging reactive oxygen species from cigarette smoke

    International Nuclear Information System (INIS)

    Yoshitomi, Toru; Kuramochi, Kazuhiro; Binh Vong, Long; Nagasaki, Yukio

    2014-01-01

    We developed a nitroxide radicals–containing polymer (NRP), which is composed of poly(4-methylstyrene) possessing nitroxide radicals as a side chain via amine linkage, to scavenge reactive oxygen species (ROS) from cigarette smoke. In this study, the NRP was coated onto cigarette filters and its ROS-scavenging activity from streaming cigarette smoke was evaluated. The intensity of electron spin resonance signals of the NRP in the filter decreased after exposure to cigarette smoke, indicating consumption of nitroxide radicals. To evaluate the ROS-scavenging activity of the NRP-coated filter, the amount of peroxy radicals in an extract of cigarette smoke was measured using UV–visible spectrophotometry and 1,1-diphenyl-2-picrylhydrazyl (DPPH). The absorbance of DPPH at 517 nm decreased with exposure to cigarette smoke. When NRP-coated filters were used, the decrease in the absorbance of DPPH was prevented. In contrast, both poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters, which have no nitroxide radical, did not show any effect, indicating that the nitroxide radicals in the NRP scavenge the ROS in cigarette smoke. As a result, the extract of cigarette smoke passed through the NRP-coated filter has a lower cellular toxicity than smoke passed through poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters. Accordingly, NRP is a promising material for ROS scavenging from cigarette smoke. (papers)

  19. [Comparison of reactive oxygen species production in neat semen and washed spermatozoa].

    Science.gov (United States)

    Svobodová, M; Oborná, I; Fingerová, H; Novotný, J; Brezinová, J; Radová, L; Vyslouzilová, J; Horáková, J; Grohmannová, J

    2009-12-01

    To determine Reactive Oxygen Species (ROS) production in neat semen and spermatozoa suspension using chemiluminescence and to examine correlation between both methods. Prospective laboratory study. Department of Obstetric and Gynecology, University Hospital, Olomouc. The study included fertile volunteers (FV, n = 17), men from infertile couples (NM, n = 19) and men with idiopathic infertility (NMI, n = 15). ROS levels were determined by the same method in neat and washed semen samples. The ROS production in neat semen was lower than that in spermatozoa suspension. There was no significant diference in ROS production between volunteers and males from infertile couples. There was a significant correlation between log ROS in neat semen and in spermatozoa suspension in studied groups (FV r = 0.85, p = 1.5 x 10(-5); NM r = 0.76, p neat semen is simpler, faster and better reflecting the actual level of oxidative stress than the same measurement in spermatozoa suspension. The implementation of this method can complement the algorithm of diagnostics and treatment of male infertility and be helpful in selection of patients for antioxidant or antibiotic treatment.

  20. Real-time in vivo detection of biomaterial-induced reactive oxygen species.

    Science.gov (United States)

    Liu, Wendy F; Ma, Minglin; Bratlie, Kaitlin M; Dang, Tram T; Langer, Robert; Anderson, Daniel G

    2011-03-01

    The non-specific host response to implanted biomaterials is often a key challenge of medical device design. To evaluate biocompatibility, measuring the release of reactive oxygen species (ROS) produced by inflammatory cells in response to biomaterial surfaces is a well-established method. However, the detection of ROS in response to materials implanted in vivo has not yet been demonstrated. Here, we develop a bioluminescence whole animal imaging approach to observe ROS released in response to subcutaneously-implanted materials in live animals. We compared the real-time generation of ROS in response to two representative materials, polystyrene and alginate, over the course of 28 days. High levels of ROS were observed near polystyrene, but not alginate implants, and persisted throughout the course of 28 days. Histological analysis revealed that high levels of ROS correlated not only with the presence of phagocytic cells at early timepoints, but also fibrosis at later timepoints, suggesting that ROS may be involved in both the acute and chronic phase of the foreign body response. These data are the first in vivo demonstration of ROS generation in response to implanted materials, and describe a novel technique to evaluate the host response. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Challenging the dogma of mitochondrial reactive oxygen species overproduction in diabetic kidney disease.

    Science.gov (United States)

    Coughlan, Melinda T; Sharma, Kumar

    2016-08-01

    The paradigm that high glucose drives overproduction of superoxide from mitochondria as a unifying theory to explain end organ damage in diabetes complications has been tightly held for more than a decade. With the recent development of techniques and probes to measure the production of distinct reactive oxygen species (ROS) in vivo, this widely held dogma is now being challenged with the emerging view that specific ROS moieties are essential for the function of specific intracellular signaling pathways and represent normal mitochondrial function. This review will provide a balanced overview of the dual nature of ROS, detailing current evidence for ROS overproduction in diabetic kidney disease, with a focus on cell types and sources of ROS. The technical aspects of measurement of mitochondrial ROS, both in isolated mitochondria and emerging in vivo methods will be discussed. The counterargument, that mitochondrial ROS production is reduced in diabetic complications, is consistent with a growing recognition that stimulation of mitochondrial biogenesis and oxidative phosphorylation activity reduces inflammation and fibrosis. It is clear that there is an urgent need to fully characterize ROS production paying particular attention to spatiotemporal aspects and to factor in the relevance of ROS in the regulation of cellular signaling in the pathogenesis of diabetic kidney disease. With improved tools and real-time imaging capacity, a greater understanding of the complex role of ROS will be able to guide novel therapeutic regimens. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  2. Fine tuning of reactive oxygen species homeostasis regulates primed immune responses in Arabidopsis.

    Science.gov (United States)

    Pastor, Victoria; Luna, Estrella; Ton, Jurriaan; Cerezo, Miguel; García-Agustín, Pilar; Flors, Victor

    2013-11-01

    Selected stimuli can prime the plant immune system for a faster and stronger defense reaction to pathogen attack. Pretreatment of Arabidopsis with the chemical agent β-aminobutyric acid (BABA) augmented H2O2 and callose production after induction with the pathogen-associated molecular pattern (PAMP) chitosan, or inoculation with the necrotrophic fungus Plectosphaerella cucumerina. However, BABA failed to prime H2O2 and callose production after challenge with the bacterial PAMP Flg22. Analysis of Arabidopsis mutants in reactive oxygen species (ROS) production (rbohD) or ROS scavenging (pad2, vtc1, and cat2) suggested a regulatory role for ROS homeostasis in priming of chitosan- and P. cucumerina-inducible callose and ROS. Moreover, rbohD and pad2 were both impaired in BABA-induced resistance against P. cucumerina. Gene expression analysis revealed direct induction of NADPH/respiratory burst oxidase protein D (RBOHD), γ-glutamylcysteine synthetase 1 (GSH1), and vitamin C defective 1 (VTC1) genes after BABA treatment. Conversely, ascorbate peroxidase 1 (APX1) transcription was repressed by BABA after challenge with chitosan or P. cucumerina, probably to provide a more oxidized environment in the cell and facilitate augmented ROS accumulation. Measuring ratios between reduced and oxidized glutathione confirmed that augmented defense expression in primed plants is associated with a more oxidized cellular status. Together, our data indicate that an altered ROS equilibrium is required for augmented defense expression in primed plants.

  3. Interaction between Mitochondrial Reactive Oxygen Species, Heme Oxygenase, and Nitric Oxide Synthase Stimulates Phagocytosis in Macrophages

    Directory of Open Access Journals (Sweden)

    Andrea Müllebner

    2018-01-01

    Full Text Available BackgroundMacrophages are cells of the innate immune system that populate every organ. They are required not only for defense against invading pathogens and tissue repair but also for maintenance of tissue homeostasis and iron homeostasis.AimThe aim of this study is to understand whether heme oxygenase (HO and nitric oxide synthase (NOS contribute to the regulation of nicotinamide adenine dinucleotide phosphate oxidase (NOX activity and phagocytosis, two key components of macrophage function.MethodsThis study was carried out using resting J774A.1 macrophages treated with hemin or vehicle. Activity of NOS, HO, or NOX was inhibited using specific inhibitors. Reactive oxygen species (ROS formation was determined by Amplex® red assay, and phagocytosis was measured using fluorescein isothiocyanate-labeled bacteria. In addition, we analyzed the fate of the intracellular heme by using electron spin resonance.ResultsWe show that both enzymes NOS and HO are essential for phagocytic activity of macrophages. NOS does not directly affect phagocytosis, but stimulates NOX activity via nitric oxide-triggered ROS production of mitochondria. Treatment of macrophages with hemin results in intracellular accumulation of ferrous heme and an inhibition of phagocytosis. In contrast to NOS, HO products, including carbon monoxide, neither clearly affect NOX activity nor clearly affect phagocytosis, but phagocytosis is accelerated by HO-mediated degradation of heme.ConclusionBoth enzymes contribute to the bactericidal activity of macrophages independently, by controlling different pathways.

  4. Reactive Oxygen Species Regulate the Inflammatory Function of NKT Cells through Promyelocytic Leukemia Zinc Finger.

    Science.gov (United States)

    Kim, Yeung-Hyen; Kumar, Ajay; Chang, Cheong-Hee; Pyaram, Kalyani

    2017-11-15

    Reactive oxygen species (ROS) are byproducts of aerobic metabolism and contribute to both physiological and pathological conditions as second messengers. ROS are essential for activation of T cells, but how ROS influence NKT cells is unknown. In the present study, we investigated the role of ROS in NKT cell function. We found that NKT cells, but not CD4 or CD8 T cells, have dramatically high ROS in the spleen and liver of mice but not in the thymus or adipose tissues. Accordingly, ROS-high NKT cells exhibited increased susceptibility and apoptotic cell death with oxidative stress. High ROS in the peripheral NKT cells were primarily produced by NADPH oxidases and not mitochondria. We observed that sorted ROS-high NKT cells were enriched in NKT1 and NKT17 cells, whereas NKT2 cells were dominant in ROS-low cells. Furthermore, treatment of NKT cells with antioxidants led to reduced frequencies of IFN-γ- and IL-17-expressing cells, indicating that ROS play a role in regulating the inflammatory function of NKT cells. The transcription factor promyelocytic leukemia zinc finger (PLZF) seemed to control the ROS levels. NKT cells from adipose tissues that do not express PLZF and those from PLZF haplodeficient mice have low ROS. Conversely, ROS were highly elevated in CD4 T cells from mice ectopically expressing PLZF. Thus, our findings demonstrate that PLZF controls ROS levels, which in turn governs the inflammatory function of NKT cells. Copyright © 2017 by The American Association of Immunologists, Inc.

  5. Reactive oxygen species as a signal in glucose-stimulated insulin secretion.

    Science.gov (United States)

    Pi, Jingbo; Bai, Yushi; Zhang, Qiang; Wong, Victoria; Floering, Lisa M; Daniel, Kiefer; Reece, Jeffrey M; Deeney, Jude T; Andersen, Melvin E; Corkey, Barbara E; Collins, Sheila

    2007-07-01

    One of the unique features of beta-cells is their relatively low expression of many antioxidant enzymes. This could render beta-cells susceptible to oxidative damage but may also provide a system that is sensitive to reactive oxygen species as signals. In isolated mouse islets and INS-1(832/13) cells, glucose increases intracellular accumulation of H2O2. In both models, insulin secretion could be stimulated by provision of either exogenous H2O2 or diethyl maleate, which raises intracellular H2O2 levels. Provision of exogenous H2O2 scavengers, including cell permeable catalase and N-acetyl-L-cysteine, inhibited glucose-stimulated H2O2 accumulation and insulin secretion (GSIS). In contrast, cell permeable superoxide dismutase, which metabolizes superoxide into H2O2, had no effect on GSIS. Because oxidative stress is an important risk factor for beta-cell dysfunction in diabetes, the relationship between glucose-induced H2O2 generation and GSIS was investigated under various oxidative stress conditions. Acute exposure of isolated mouse islets or INS-1(832/13) cells to oxidative stressors, including arsenite, 4-hydroxynonenal, and methylglyoxal, led to decreased GSIS. This impaired GSIS was associated with increases in a battery of endogenous antioxidant enzymes. Taken together, these findings suggest that H2O2 derived from glucose metabolism is one of the metabolic signals for insulin secretion, whereas oxidative stress may disturb its signaling function.

  6. Small molecule CP-31398 induces reactive oxygen species-dependent apoptosis in human multiple myeloma.

    Science.gov (United States)

    Arihara, Yohei; Takada, Kohichi; Kamihara, Yusuke; Hayasaka, Naotaka; Nakamura, Hajime; Murase, Kazuyuki; Ikeda, Hiroshi; Iyama, Satoshi; Sato, Tsutomu; Miyanishi, Koji; Kobune, Masayoshi; Kato, Junji

    2017-09-12

    Reactive oxygen species (ROS) are normal byproducts of a wide variety of cellular processes. ROS have dual functional roles in cancer cell pathophysiology. At low to moderate levels, ROS act as signaling transducers to activate cell proliferation, migration, invasion, and angiogenesis. In contrast, high levels of ROS induce cell death. In multiple myeloma (MM), ROS overproduction is the trigger for apoptosis induced by several anticancer compounds, including proteasome inhibitors. However, no drugs for which oxidative stress is the main mechanism of action are currently used for treatment of MM in clinical situations. In this study, we demonstrate that the p53-activating small molecule CP-31398 (CP) effectively inhibits the growth of MM cell lines and primary MM isolates from patients. CP also suppresses the growth of MM xenografts in mice. Mechanistically, CP was found to induce intrinsic apoptosis in MM cells via increasing ROS production. Interestingly, CP-induced apoptosis occurs regardless of the p53 status, suggesting that CP has additional mechanisms of action. Our findings thus indicate that CP could be an attractive candidate for treatment of MM patients harboring p53 abnormalities; this satisfies an unmet clinical need, as such individuals currently have a poor prognosis.

  7. Brain infarction correlates more closely with acrolein than with reactive oxygen species.

    Science.gov (United States)

    Saiki, Ryotaro; Park, Hyerim; Ishii, Itsuko; Yoshida, Madoka; Nishimura, Kazuhiro; Toida, Toshihiko; Tatsukawa, Hideki; Kojima, Soichi; Ikeguchi, Yoshihiko; Pegg, Anthony E; Kashiwagi, Keiko; Igarashi, Kazuei

    2011-01-28

    Although it is thought that the major factor responsible for cell damage is reactive oxygen species (ROS), our recent studies have shown that acrolein is more toxic than ROS. Thus, the relative importance of acrolein and ROS in cell damage during brain infarction was compared using photochemically induced thrombosis model mice. The levels of acrolein-conjugated albumin, and of 4-hydroxynonenal (HNE)-conjugated albumin and 8-OHdG were evaluated as indicators of damage produced by acrolein and ROS, respectively. The increase in acrolein-conjugated albumin was much greater than the increase in HNE-conjugated albumin or 8-OHdG, suggesting that acrolein is more strongly involved in cell damage than ROS during brain infarction. It was also shown that infarction led more readily to RNA damage than to DNA or phospholipid damage. As a consequence, polyamines were released from RNA, and acrolein was produced from polyamines, especially from spermine by spermine oxidase. Production of acrolein from spermine by spermine oxidase was clarified using spermine synthase-deficient Gy mice and transglutaminase 2-knockout mice, in which spermine content is negligible or spermidine/spermine N(1)-acetyltransferase activity is elevated. Copyright © 2010 Elsevier Inc. All rights reserved.

  8. Acrolein activates matrix metalloproteinases by increasing reactive oxygen species in macrophages.

    Science.gov (United States)

    O'Toole, Timothy E; Zheng, Yu-Ting; Hellmann, Jason; Conklin, Daniel J; Barski, Oleg; Bhatnagar, Aruni

    2009-04-15

    Acrolein is a ubiquitous component of environmental pollutants such as automobile exhaust, cigarette, wood, and coal smoke. It is also a natural constituent of several foods and is generated endogenously during inflammation or oxidation of unsaturated lipids. Because increased inflammation and episodic exposure to acrolein-rich pollutants such as traffic emissions or cigarette smoke have been linked to acute myocardial infarction, we examined the effects of acrolein on matrix metalloproteinases (MMPs), which destabilize atherosclerotic plaques. Our studies show that exposure to acrolein resulted in the secretion of MMP-9 from differentiated THP-1 macrophages. Acrolein-treatment of macrophages also led to an increase in reactive oxygen species (ROS), free intracellular calcium ([Ca2+](i)), and xanthine oxidase (XO) activity. ROS production was prevented by allopurinol, but not by rotenone or apocynin and by buffering changes in [Ca2+](I) with BAPTA-AM. The increase in MMP production was abolished by pre-treatment with the antioxidants Tiron and N-acetyl cysteine (NAC) or with the xanthine oxidase inhibitors allopurinol or oxypurinol. Finally, MMP activity was significantly stimulated in aortic sections from apoE-null mice containing advanced atherosclerotic lesions after exposure to acrolein ex vivo. These observations suggest that acrolein exposure results in MMP secretion from macrophages via a mechanism that involves an increase in [Ca2+](I), leading to xanthine oxidase activation and an increase in ROS production. ROS-dependent activation of MMPs by acrolein could destabilize atherosclerotic lesions during brief episodes of inflammation or pollutant exposure.

  9. Acrolein activates matrix metalloproteinases by increasing reactive oxygen species in macrophages

    International Nuclear Information System (INIS)

    O'Toole, Timothy E.; Zheng Yuting; Hellmann, Jason; Conklin, Daniel J.; Barski, Oleg; Bhatnagar, Aruni

    2009-01-01

    Acrolein is a ubiquitous component of environmental pollutants such as automobile exhaust, cigarette, wood, and coal smoke. It is also a natural constituent of several foods and is generated endogenously during inflammation or oxidation of unsaturated lipids. Because increased inflammation and episodic exposure to acrolein-rich pollutants such as traffic emissions or cigarette smoke have been linked to acute myocardial infarction, we examined the effects of acrolein on matrix metalloproteinases (MMPs), which destabilize atherosclerotic plaques. Our studies show that exposure to acrolein resulted in the secretion of MMP-9 from differentiated THP-1 macrophages. Acrolein-treatment of macrophages also led to an increase in reactive oxygen species (ROS), free intracellular calcium ([Ca 2+ ] i ), and xanthine oxidase (XO) activity. ROS production was prevented by allopurinol, but not by rotenone or apocynin and by buffering changes in [Ca 2+ ] I with BAPTA-AM. The increase in MMP production was abolished by pre-treatment with the antioxidants Tiron and N-acetyl cysteine (NAC) or with the xanthine oxidase inhibitors allopurinol or oxypurinol. Finally, MMP activity was significantly stimulated in aortic sections from apoE-null mice containing advanced atherosclerotic lesions after exposure to acrolein ex vivo. These observations suggest that acrolein exposure results in MMP secretion from macrophages via a mechanism that involves an increase in [Ca 2+ ] I , leading to xanthine oxidase activation and an increase in ROS production. ROS-dependent activation of MMPs by acrolein could destabilize atherosclerotic lesions during brief episodes of inflammation or pollutant exposure.

  10. Plasmonic photocatalyst-like fluorescent proteins for generating reactive oxygen species

    Science.gov (United States)

    Leem, Jung Woo; Kim, Seong-Ryul; Choi, Kwang-Ho; Kim, Young L.

    2018-03-01

    The recent advances in photocatalysis have opened a variety of new possibilities for energy and biomedical applications. In particular, plasmonic photocatalysis using hybridization of semiconductor materials and metal nanoparticles has recently facilitated the rapid progress in enhancing photocatalytic efficiency under visible or solar light. One critical underlying aspect of photocatalysis is that it generates and releases reactive oxygen species (ROS) as intermediate or final products upon light excitation or activation. Although plasmonic photocatalysis overcomes the limitation of UV irradiation, synthesized metal/semiconductor nanomaterial photocatalysts often bring up biohazardous and environmental issues. In this respect, this review article is centered in identifying natural photosensitizing organic materials that can generate similar types of ROS as those of plasmonic photocatalysis. In particular, we propose the idea of plasmonic photocatalyst-like fluorescent proteins for ROS generation under visible light irradiation. We recapitulate fluorescent proteins that have Type I and Type II photosensitization properties in a comparable manner to plasmonic photocatalysis. Plasmonic photocatalysis and protein photosensitization have not yet been compared systemically in terms of ROS photogeneration under visible light, although the phototoxicity and cytotoxicity of some fluorescent proteins are well recognized. A comprehensive understanding of plasmonic photocatalyst-like fluorescent proteins and their potential advantages will lead us to explore new environmental, biomedical, and defense applications.

  11. Reactive oxygen species production and Brugia pahangi survivorship in Aedes polynesiensis with artificial Wolbachia infection types.

    Directory of Open Access Journals (Sweden)

    Elizabeth S Andrews

    Full Text Available Heterologous transinfection with the endosymbiotic bacterium Wolbachia has been shown previously to induce pathogen interference phenotypes in mosquito hosts. Here we examine an artificially infected strain of Aedes polynesiensis, the primary vector of Wuchereria bancrofti, which is the causative agent of Lymphatic filariasis (LF throughout much of the South Pacific. Embryonic microinjection was used to transfer the wAlbB infection from Aedes albopictus into an aposymbiotic strain of Ae. polynesiensis. The resulting strain (designated "MTB" experiences a stable artificial infection with high maternal inheritance. Reciprocal crosses of MTB with naturally infected wild-type Ae. polynesiensis demonstrate strong bidirectional incompatibility. Levels of reactive oxygen species (ROS in the MTB strain differ significantly relative to that of the wild-type, indicating an impaired ability to regulate oxidative stress. Following a challenge with Brugia pahangi, the number of filarial worms achieving the infective stage is significantly reduced in MTB as compared to the naturally infected and aposymbiotic strains. Survivorship of MTB differed significantly from that of the wild-type, with an interactive effect between survivorship and blood feeding. The results demonstrate a direct correlation between decreased ROS levels and decreased survival of adult female Aedes polynesiensis. The results are discussed in relation to the interaction of Wolbachia with ROS production and antioxidant expression, iron homeostasis and the insect immune system. We discuss the potential applied use of the MTB strain for impacting Ae. polynesiensis populations and strategies for reducing LF incidence in the South Pacific.

  12. Reactive oxygen species inactivation improves pancreatic capillary blood flow in caerulein-induced pancreatitis in rats

    Directory of Open Access Journals (Sweden)

    Meirelles Jr. Roberto Ferreira

    2003-01-01

    Full Text Available PURPOSE: Reactive oxygen species (ROS inactivation was studied to determine alterations in the pancreatic capillary blood flow (PCBF during caerulein-induced pancreatitis in rats. METHODS: A laser-Doppler flowmeter to measure PCBF and N-t-Butyl-Phenylnitrone (PBN compound to inactivate ROS were used. Forty rats were divided in groups: 1 control; 2 caerulein; 3 PBN; 4 caerulein+PBN. Serum biochemistry and histopathological analyses were performed. RESULTS: PCBF measured a mean of 109.08 ± 14.54%, 68.24 ± 10.47%, 102.18 ± 10.23% and 87.73 ± 18.72% in groups 1, 2, 3 and 4, respectively. PCBF in groups 2 and 4 decreased 31.75 ± 16.79% and 12.26 ± 15.24%, respectively. Serum amylase was 1323.70 ± 239.10 U/l, 2184.60 ± 700.46 U/l, 1379.80 ± 265.72 U/l and 1622.10 ± 314.60 U/l in groups 1, 2, 3 and 4, respectively. There was a significant difference in the PCBF and serum amylase when compared groups 2 and 4. Cytoplasmatic vacuolation was present in groups 2 and 4. Otherwise, no qualitative changes were seen. CONCLUSION: ROS inactivation improves PCBF and minimizes the serum amylase increase during caerulein-induced pancreatitis. ROS effect may be one of the leading causative events in this model of acute pancreatitis.

  13. Controllable generation of reactive oxygen species by femtosecond-laser irradiation

    Science.gov (United States)

    Yan, Wei; He, Hao; Wang, Yintao; Wang, Yisen; Hu, Minglie; Wang, Chingyue

    2014-02-01

    Femtosecond lasers have been advancing Biophotonics research in the past two decades with multiphoton microscopy, microsurgery, and photodynamic therapy. Nevertheless, laser irradiation is identified to bring photodamage to cells via reactive oxygen species (ROS) generation with unclear mechanism. Meanwhile, currently in biological researches, there is no effective method to provide controllable ROS production precisely, which originally is leaked from mitochondria during respiration and plays a key role in a lot of important cellular processes and cellular signaling pathways. In this study, we show the process of how the tightly focused femtosecond-laser induces ROS generation solely in mitochondria at the very beginning and then release to cytosol if the stimulus is intense enough. At certain weak power levels, the laser pulses induce merely moderate Ca2+ release but this is necessary for the laser to generate ROS in mitochondria. Cellular original ROS are also involved with a small contribution. When the power is above a threshold, ROS are then released to cytosol, indicating photodamage overwhelming cellular repair ability. The mechanisms in those two cases are quite different. Those results clarify parts of the mechanism in laser-induced ROS generation. Hence, it is possible to further this optical scheme to provide controllable ROS generation for ROS-related biological researches including mitochondrial diseases and aging.

  14. Detection of the Level of Reactive Oxygen Species Induced by Ionizing Radiation in Cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Chung, Dong Min; Kim, Jin-Hong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    By definition, the direct effect is referred to interaction between photon and DNA molecule, whereas the indirect effect is mediated by the reactive oxygen species (ROS) generated by radiolysis and subsequent reaction. It has been reported that ROS produced after exposure to IR can react with cellular materials such as DNA, proteins, carbohydrates and lipids. ROS is free radicals such as the superoxide anion, hydroxyl radicals and the non-radical hydrogen peroxide. Cells generate ROS during aerobic metabolism. Excessive production of ROS can lead to oxidative stress, genetic alteration and even cell death. It has been reported that ROS plays a critical role in radiation-induced cell injury. Thus, it is of great interest to determine the radiation-induced ROS level. Many kinds of methods to detect the level of ROS have been developed so far. There were random changes of fluorescence intensity in the treatment after irradiation. This result meant that this protocol was not appropriate for determination of radiation-induced ROS. On the other hand, the fluorescence intensity was increased in a dose-dependent manner when the cells were treated with the DCFH-DA solution before irradiation. Conclusions can be drawn from the experimental results of this study. In order to properly measure the ROS level in the cells exposed to ionizing radiation, the cells should be treated with the DCFH-DA solution before irradiation.

  15. Effects of combined radiofrequency radiation exposure on levels of reactive oxygen species in neuronal cells

    International Nuclear Information System (INIS)

    Kang, Kyoung Ah; Lee, Hyung Chul; Lee, Je-Jung

    2014-01-01

    The objective of this study was to investigate the effects of the combined RF radiation (837 MHz CDMA plus 1950 MHz WCDMA) signal on levels of intracellular reactive oxygen species (ROS) in neuronal cells. Exposure of the combined RF signal was conducted at specific absorption rate values of 2 W/kg of CDMA plus 2 W/kg of WCDMA for 2 h. Co-exposure to combined RF radiation with either H 2 O 2 or menadione was also performed. The experimental exposure groups were incubator control, sham-exposed, combined RF radiation-exposed with or without either H 2 O 2 or menadione groups. The intracellular ROS level was measured by flow cytometry using the fluorescent probe dichlorofluorescein diacetate. Intracellular ROS levels were not consistently affected by combined RF radiation exposure alone in a time-dependent manner in U87, PC12 or SH-SY5Y cells. In neuronal cells exposed to combined RF radiation with either H 2 O 2 or menadione, intracellular ROS levels showed no statically significant alteration compared with exposure to menadione or H 2 O 2 alone. These findings indicate that neither combined RF radiation alone nor combined RF radiation with menadione or H 2 O 2 influences the intracellular ROS level in neuronal cells such as U87, PC12 or SH-SY5Y. (author)

  16. Reactive oxygen species induced by Streptococcus pyogenes invasion trigger apoptotic cell death in infected epithelial cells.

    Science.gov (United States)

    Aikawa, Chihiro; Nozawa, Takashi; Maruyama, Fumito; Tsumoto, Kohei; Hamada, Shigeyuki; Nakagawa, Ichiro

    2010-06-01

    Streptococcus pyogenes (group A streptococcus, GAS), one of the most common pathogens of humans, attaches and invades into human pharyngeal or skin epithelial cells. We have previously reported that induction of apoptosis is associated with GAS invasion, which induces mitochondrial dysfunction and apoptotic cell death. We demonstrate here that GAS-induced apoptosis is mediated by reactive oxygen species (ROS) production. Both the induction of apoptosis and ROS production markedly increased upon invasion of wild-type GAS strain JRS4 into HeLa cells; however, the apoptotic response was not observed in fibronectin-binding protein F1-disrupted mutant SAM1-infected cells. In Bcl-2-overexpressing HeLa cells (HBD98-2-4), the induction of apoptosis, ROS production and mitochondrial dysfunction were significantly suppressed, whereas the numbers of invaded GAS was not different between HeLa (mock cells) and the HeLa HBD98-2-4 cells. Whereas Rac1 activation occurred during GAS invasion, ROS production in GAS-infected cells was clearly inhibited by transfection with the Rac1 mutants (L37 or V12L37), but not by the dominant active mutant (V12L61) or by the dominant negative mutant (N17). These observations indicate that GAS invasion triggers ROS production through Rac1 activation and generated ROS induced mitochondrial dysfunction leading to cellular apoptosis.

  17. Reactive oxygen species mediates homocysteine-induced mitochondrial biogenesis in human endothelial cells: Modulation by antioxidants

    International Nuclear Information System (INIS)

    Perez-de-Arce, Karen; Foncea, Rocio; Leighton, Federico

    2005-01-01

    It has been proposed that homocysteine (Hcy)-induces endothelial dysfunction and atherosclerosis by generation of reactive oxygen species (ROS). A previous report has shown that Hcy promotes mitochondrial damage. Considering that oxidative stress can affect mitochondrial biogenesis, we hypothesized that Hcy-induced ROS in endothelial cells may lead to increased mitochondrial biogenesis. We found that Hcy-induced ROS (1.85-fold), leading to a NF-κB activation and increase the formation of 3-nitrotyrosine. Furthermore, expression of the mitochondrial biogenesis factors, nuclear respiratory factor-1 and mitochondrial transcription factor A, was significantly elevated in Hcy-treated cells. These changes were accompanied by increase in mitochondrial mass and higher mRNA and protein expression of the subunit III of cytochrome c oxidase. These effects were significantly prevented by pretreatment with the antioxidants, catechin and trolox. Taken together, our results suggest that ROS is an important mediator of mitochondrial biogenesis induced by Hcy, and that modulation of oxidative stress by antioxidants may protect against the adverse vascular effects of Hcy

  18. Iron- and ferritin-dependent reactive oxygen species distribution: impact on Arabidopsis root system architecture.

    Science.gov (United States)

    Reyt, Guilhem; Boudouf, Soukaina; Boucherez, Jossia; Gaymard, Frédéric; Briat, Jean-Francois

    2015-03-01

    Iron (Fe) homeostasis is integrated with the production of reactive oxygen species (ROS), and distribution at the root tip participates in the control of root growth. Excess Fe increases ferritin abundance, enabling the storage of Fe, which contributes to protection of plants against Fe-induced oxidative stress. AtFer1 and AtFer3 are the two ferritin genes expressed in the meristematic zone, pericycle and endodermis of the Arabidopsis thaliana root, and it is in these regions that we observe Fe stained dots. This staining disappears in the triple fer1-3-4 ferritin mutant. Fe excess decreases primary root length in the same way in wild-type and in fer1-3-4 mutant. In contrast, the Fe-mediated decrease of lateral root (LR) length and density is enhanced in fer1-3-4 plants due to a defect in LR emergence. We observe that this interaction between excess Fe, ferritin, and root system architecture (RSA) is in part mediated by the H2O2/O2·- balance between the root cell proliferation and differentiation zones regulated by the UPB1 transcription factor. Meristem size is also decreased in response to Fe excess in ferritin mutant plants, implicating cell cycle arrest mediated by the ROS-activated SMR5/SMR7 cyclin-dependent kinase inhibitors pathway in the interaction between Fe and RSA. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  19. The Emerging Role of Reactive Oxygen Species Signaling during Lateral Root Development.

    Science.gov (United States)

    Manzano, Concepción; Pallero-Baena, Mercedes; Casimiro, Ilda; De Rybel, Bert; Orman-Ligeza, Beata; Van Isterdael, Gert; Beeckman, Tom; Draye, Xavier; Casero, Pedro; Del Pozo, Juan C

    2014-07-01

    Overall root architecture is the combined result of primary and lateral root growth and is influenced by both intrinsic genetic programs and external signals. One of the main questions for root biologists is how plants control the number of lateral root primordia and their emergence through the main root. We recently identified S-phase kinase-associated protein2 (SKP2B) as a new early marker for lateral root development. Here, we took advantage of its specific expression pattern in Arabidopsis (Arabidopsis thaliana) in a cell-sorting and transcriptomic approach to generate a lateral root-specific cell sorting SKP2B data set that represents the endogenous genetic developmental program. We first validated this data set by showing that many of the identified genes have a function during root growth or lateral root development. Importantly, genes encoding peroxidases were highly represented in our data set. Thus, we next focused on this class of enzymes and showed, using genetic and chemical inhibitor studies, that peroxidase activity and reactive oxygen species signaling are specifically required during lateral root emergence but, intriguingly, not for primordium specification itself. © 2014 American Society of Plant Biologists. All Rights Reserved.

  20. Dim artificial light at night affects mating, reproductive output, and reactive oxygen species in Drosophila melanogaster.

    Science.gov (United States)

    McLay, Lucy Katherine; Nagarajan-Radha, Venkatesh; Green, Mark Philip; Jones, Therésa Melanie

    2018-05-07

    Humans are lighting the night-time environment with ever increasing extent and intensity, resulting in a variety of negative ecological effects in individuals and populations. Effects of light at night on reproductive fitness traits are demonstrated across taxa however, the mechanisms underlying these effects are largely untested. One possible mechanism is that light at night may result in perturbed reactive oxygen species (ROS) and oxidative stress levels. Here, we reared Drosophila melanogaster under either dim (10 lx) light or no light (0 lx) at night for three generations and then compared mating and lifetime oviposition patterns. In a second experiment, we explored whether exposure to light at night treatments resulted in variation in ROS levels in the heads and ovaries of six, 23- and 36-day-old females. We demonstrate that dim light at night affects mating and reproductive output: 10 lx flies courted for longer prior to mating, and female oviposition patterns differed to 0 lx females. ROS levels were lower in the ovaries but not heads, of 10 lx compared with 0 lx females. We suggest that reduced ROS levels may reflect changes in ovarian physiology and cell signaling, which may be related to the differences observed in oviposition patterns. Taken together, our results indicate negative consequences for invertebrates under more stressful, urban, lit conditions and further investigation into the mechanisms driving these changes is warranted to manage invertebrate communities in a brighter future. © 2018 Wiley Periodicals, Inc.

  1. Photoreactivity of Metal-Organic Frameworks in Aqueous Solutions: Metal Dependence of Reactive Oxygen Species Production.

    Science.gov (United States)

    Liu, Kai; Gao, Yanxin; Liu, Jing; Wen, Yifan; Zhao, Yingcan; Zhang, Kunyang; Yu, Gang

    2016-04-05

    Promising applications of metal-organic frameworks (MOFs) in various fields have raised concern over their environmental fate and safety upon inevitable discharge into aqueous environments. Currently, no information regarding the transformation processes of MOFs is available. Due to the presence of repetitive π-bond structure and semiconductive property, photochemical transformations are an important fate process that affects the performance of MOFs in practical applications. In the current study, the generation of reactive oxygen species (ROS) in isoreticular MIL-53s was studied. Scavengers were employed to probe the production of (1)O2, O2(•-), and •OH, respectively. In general, MIL-53(Cr) and MIL-53(Fe) are dominated by type I and II photosensitization reactions, respectively, and MIL-53(Al) appears to be less photoreactive. The generation of ROS in MIL-53(Fe) may be underestimated due to dismutation. Further investigation of MIL-53(Fe) encapsulated diclofenac transformation revealed that diclofenac can be easily transformed by MIL-53(Fe) generated ROS. However, the cytotoxicity results implied that the ROS generated from MIL-53s have little effect on the viability of the human hepatocyte (HepG2) cell line. These results suggest that the photogeneration of ROS by MOFs may be metal-node dependent, and the application of MIL-53s as drug carriers needs to be carefully considered due to their high photoreactivity.

  2. Global Plant Stress Signaling: Reactive Oxygen Species at the Cross-Road

    Directory of Open Access Journals (Sweden)

    Nasser eSewelam

    2016-02-01

    Full Text Available Current technologies have changed biology into a data-intensive field and significantly increased our understanding of signal transduction pathways in plants. However, global defense signaling networks in plants have not been established yet. Considering the apparent intricate nature of signaling mechanisms in plants (due to their sessile nature, studying the points at which different signaling pathways converge, rather than the branches, represents a good start to unravel global plant signaling networks. In this regard, growing evidence shows that the generation of reactive oxygen species (ROS is one of the most common plant responses to different stresses, representing a point at which various signaling pathways come together. In this review, the complex nature of plant stress signaling networks will be discussed. An emphasis on different signaling players with a specific attention to ROS as the primary source of the signaling battery in plants will be presented. The interactions between ROS and other signaling components, e.g. calcium, redox homeostasis, membranes, G-proteins, MAPKs, plant hormones and transcription factors will be assessed. A better understanding of the vital roles ROS are playing in plant signaling would help innovate new strategies to improve plant productivity under the circumstances of the increasing severity of environmental conditions and the high demand of food and energy worldwide

  3. Cold stress increases reactive oxygen species formation via TRPA1 activation in A549 cells.

    Science.gov (United States)

    Sun, Wenwu; Wang, Zhonghua; Cao, Jianping; Cui, Haiyang; Ma, Zhuang

    2016-03-01

    Reactive oxygen species (ROS) are responsible for lung damage during inhalation of cold air. However, the mechanism of the ROS production induced by cold stress in the lung is still unclear. In this work, we measured the changes of ROS and the cytosolic Ca(2+) concentration ([Ca(2+)]c) in A549 cell. We observed that cold stress (from 20 to 5 °C) exposure of A549 cell resulted in an increase of ROS and [Ca(2+)]c, which was completely attenuated by removing Ca(2+) from medium. Further experiments showed that cold-sensing transient receptor potential subfamily member 1 (TRPA1) agonist (allyl isothiocyanate, AITC) increased the production of ROS and the level of [Ca(2+)]c in A549 cell. Moreover, HC-030031, a TRPA1 selective antagonist, significantly inhibited the enhanced ROS and [Ca(2+)]c induced by AITC or cold stimulation, respectively. Taken together, these data demonstrated that TRPA1 activation played an important role in the enhanced production of ROS induced by cold stress in A549 cell.

  4. Controlled intracellular generation of reactive oxygen species in human mesenchymal stem cells using porphyrin conjugated nanoparticles.

    Science.gov (United States)

    Lavado, Andrea S; Chauhan, Veeren M; Zen, Amer Alhaj; Giuntini, Francesca; Jones, D Rhodri E; Boyle, Ross W; Beeby, Andrew; Chan, Weng C; Aylott, Jonathan W

    2015-09-14

    Nanoparticles capable of generating controlled amounts of intracellular reactive oxygen species (ROS), that advance the study of oxidative stress and cellular communication, were synthesized by functionalizing polyacrylamide nanoparticles with zinc(II) porphyrin photosensitisers. Controlled ROS production was demonstrated in human mesenchymal stem cells (hMSCs) through (1) production of nanoparticles functionalized with varying percentages of Zn(II) porphyrin and (2) modulating the number of doses of excitation light to internalized nanoparticles. hMSCs challenged with nanoparticles functionalized with increasing percentages of Zn(II) porphyrin and high numbers of irradiations of excitation light were found to generate greater amounts of ROS. A novel dye, which is transformed into fluorescent 7-hydroxy-4-trifluoromethyl-coumarin in the presence of hydrogen peroxide, provided an indirect indicator for cumulative ROS production. The mitochondrial membrane potential was monitored to investigate the destructive effect of increased intracellular ROS production. Flow cytometric analysis of nanoparticle treated hMSCs suggested irradiation with excitation light signalled controlled apoptotic cell death, rather than uncontrolled necrotic cell death. Increased intracellular ROS production did not induce phenotypic changes in hMSC subcultures.

  5. Screening reactive oxygen species scavenging properties of platinum nanoparticles on a microfluidic chip.

    Science.gov (United States)

    Zheng, Wenfu; Jiang, Bo; Hao, Yi; Zhao, Yuyun; Zhang, Wei; Jiang, Xingyu

    2014-09-12

    Hyperglycemia, hyperlipidemia and inflammation are key risk factors for atherosclerosis and can lead to overproduction of reactive oxygen species (ROS), which plays a critical role in vascular endothelial dysfunction and subsequent progress of atherosclerosis. However, there is currently a lack of effective drugs that deal with ROS. Platinum nanoparticles (Pt-NPs) have proven to be promising antioxidant drugs in vitro and in vivo. To optimize the efficacy of Pt-NP based drugs, we synthesized and characterized the ROS scavenging properties of three kinds of small molecules that capped Pt-NPs (Pt-AMP-NPs, Pt-ATT-NPs, Pt-MI-NPs) on a blood vessel-mimicking microfluidic chip. The Pt-NPs showed superior superoxide dismutase (SOD)-like functions and can scavenge ROS and recover compromised cell-cell junctions under hyperglycemic, hyperlipidemic and proinflammatory conditions. Amongst these NPs, Pt-AMP-NPs showed the most superior antioxidant properties, suggesting its potency to serve as a novel drug to treat vascular diseases such as atherosclerosis. Our microfluidic chip, providing physiological hemodynamic conditions for the experiments, is potentially a promising tool for a wide range of biological research on the vascular system.

  6. The Role of Reactive Oxygen Species (ROS in the Biological Activities of Metallic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Ahmed Abdal Dayem

    2017-01-01

    Full Text Available Nanoparticles (NPs possess unique physical and chemical properties that make them appropriate for various applications. The structural alteration of metallic NPs leads to different biological functions, specifically resulting in different potentials for the generation of reactive oxygen species (ROS. The amount of ROS produced by metallic NPs correlates with particle size, shape, surface area, and chemistry. ROS possess multiple functions in cellular biology, with ROS generation a key factor in metallic NP-induced toxicity, as well as modulation of cellular signaling involved in cell death, proliferation, and differentiation. In this review, we briefly explained NP classes and their biomedical applications and describe the sources and roles of ROS in NP-related biological functions in vitro and in vivo. Furthermore, we also described the roles of metal NP-induced ROS generation in stem cell biology. Although the roles of ROS in metallic NP-related biological functions requires further investigation, modulation and characterization of metallic NP-induced ROS production are promising in the application of metallic NPs in the areas of regenerative medicine and medical devices.

  7. Monochloramine produces reactive oxygen species in liver by converting xanthine dehydrogenase into xanthine oxidase.

    Science.gov (United States)

    Sakuma, Satoru; Miyoshi, Emi; Sadatoku, Namiko; Fujita, Junko; Negoro, Miki; Arakawa, Yukio; Fujimoto, Yohko

    2009-09-15

    In the present study, we assessed the influence of monochloramine (NH(2)Cl) on the conversion of xanthine dehydrogenase (XD) into xanthine oxidase (XO) in rat liver in vitro. When incubated with the partially purified cytosolic fraction from rat liver, NH(2)Cl (2.5-20 microM) dose-dependently enhanced XO activity concomitant with a decrease in XD activity, implying that NH(2)Cl can convert XD into the reactive oxygen species (ROS) producing form XO. The NH(2)Cl (5 microM)-induced XD/XO interconversion in the rat liver cytosol was completely inhibited when added in combination with an inhibitor of NH(2)Cl methionine (25 microM). A sulfhydryl reducing agent, dithiothreitol at concentrations of 0.1, 1 and 5 mM also dose-dependently reversed the NH(2)Cl (5 microM)-induced XD/XO interconversion. These imply that NH(2)Cl itself acts on the XD/XO interconversion, and that this conversion occurs at the cysteine residues in XD. Furthermore, using the fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate, it was found that NH(2)Cl could increase ROS generation in the cytoplasm of rat primary hepatocyte cultures, and that this increase might be reversed by an XO inhibitor, allopurinol. These results suggest that NH(2)Cl has the potential to convert XD into XO in the liver, which in turn may induce the ROS generation in this region.

  8. Rapid and transient stimulation of intracellular reactive oxygen species by melatonin in normal and tumor leukocytes

    International Nuclear Information System (INIS)

    Radogna, Flavia; Paternoster, Laura; De Nicola, Milena; Cerella, Claudia; Ammendola, Sergio; Bedini, Annalida; Tarzia, Giorgio; Aquilano, Katia; Ciriolo, Maria; Ghibelli, Lina

    2009-01-01

    Melatonin is a modified tryptophan with potent biological activity, exerted by stimulation of specific plasma membrane (MT1/MT2) receptors, by lower affinity intracellular enzymatic targets (quinone reductase, calmodulin), or through its strong anti-oxidant ability. Scattered studies also report a perplexing pro-oxidant activity, showing that melatonin is able to stimulate production of intracellular reactive oxygen species (ROS). Here we show that on U937 human monocytes melatonin promotes intracellular ROS in a fast (< 1 min) and transient (up to 5-6 h) way. Melatonin equally elicits its pro-radical effect on a set of normal or tumor leukocytes; intriguingly, ROS production does not lead to oxidative stress, as shown by absence of protein carbonylation, maintenance of free thiols, preservation of viability and regular proliferation rate. ROS production is independent from MT1/MT2 receptor interaction, since a) requires micromolar (as opposed to nanomolar) doses of melatonin; b) is not contrasted by the specific MT1/MT2 antagonist luzindole; c) is not mimicked by a set of MT1/MT2 high affinity melatonin analogues. Instead, chlorpromazine, the calmodulin inhibitor shown to prevent melatonin-calmodulin interaction, also prevents melatonin pro-radical effect, suggesting that the low affinity binding to calmodulin (in the micromolar range) may promote ROS production.

  9. Regulation of radiation protective agents on cell damage induced by reactive oxygen species

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Hee; Lee, Si Eun; Ju, Eun Mi; Gao, Eu Feng [Kyung Hee University, Seoul (Korea)

    2002-04-01

    In this study, we developed candidates of new radio-protective agents and elucidated the regulation mechanism of these candidates on cell damage induced by reactive oxygen species. The methanol extracts and ethylacetate fractions of NP-1, NP-5, NP-7, NP-11, NP-12 and NP-14 showed higher radical scavenging activity. The extracts of NP-7, NP-12 and NP-14 showed strong protective effect against oxidative damage induced by UV and H{sub 2}O{sub 2}. The most of samples enhanced SOD, CAT and GPX activity in V79-4 cells. The protective effect of samples on H{sub 2}O{sub 2}-induced apoptosis was observed with microscope and flow cytometer. Cells exposed to H{sub 2}O{sub 2} exhibit distinct morphological features of programmed cell death, such as nuclear fragmentation and increase in the percentage of cells with a sub-G1 DNA content. However, cells which was pretreated with samples significantly reduced the characteristics of apoptotic cells. Their morphological observation and DNA profiles were similar to those of the control cells. NP-14 which had excellent antioxidant activity restored G2/M arrest induced by oxidative stress. These data suggested that natural medicinal plants protected H{sub 2}O{sub 2}-induced apoptosis. 42 refs., 29 figs., 11 tabs. (Author)

  10. N-acetyltransferase Mpr1 confers ethanol tolerance on Saccharomyces cerevisiae by reducing reactive oxygen species

    Energy Technology Data Exchange (ETDEWEB)

    Du, Xiaoyi [Fukui Prefectural Univ., Fukui (Japan). Dept. of Bioscience; Takagi, Hiroshi [Nara Inst. of Science and Technology, Ikoma, Nara (Japan). Graduate School of Biological Sciences

    2007-07-15

    N-Acetyltransferase Mpr1 of Saccharomyces cerevisiae can reduce intracellular oxidation levels and protect yeast cells under oxidative stress, including H{sub 2}O{sub 2}, heat-shock, or freeze-thaw treatment. Unlike many antioxidant enzyme genes induced in response to oxidative stress, the MPR1 gene seems to be constitutively expressed in yeast cells. Based on a recent report that ethanol toxicity is correlated with the production of reactive oxygen species (ROS), we examined here the role of Mpr1 under ethanol stress conditions. The null mutant of the MPR1 and MPR2 genes showed hypersensitivity to ethanol stress, and the expression of the MPR1 gene conferred stress tolerance. We also found that yeast cells exhibited increased ROS levels during exposure to ethanol stress, and that Mpr1 protects yeast cells from ethanol stress by reducing intracellular ROS levels. When the MPR1 gene was overexpressed in antioxidant enzyme-deficient mutants, increased resistance to H{sub 2}O{sub 2} or heat shock was observed in cells lacking the CTA1, CTT1, or GPX1 gene encoding catalase A, catalase T, or glutathione peroxidase, respectively. These results suggest that Mpr1 might compensate the function of enzymes that detoxify H{sub 2}O{sub 2}. Hence, Mpr1 has promising potential for the breeding of novel ethanol-tolerant yeast strains. (orig.)

  11. Effects of reactive oxygen species on cellular wall disassembly of banana fruit during ripening.

    Science.gov (United States)

    Cheng, Guiping; Duan, Xuewu; Shi, John; Lu, Wangjin; Luo, Yunbo; Jiang, Weibo; Jiang, Yueming

    2008-07-15

    Fruit softening is generally attributed to cell wall disassembly. Experiments were conducted to investigate effects of various reactive oxygen species (ROS) on in vitro cellular wall disassembly of harvested banana fruit. The alcohol-extracted insoluble residue (AEIR) was obtained from the pulp tissues of banana fruit at various ripening stages and then used to examine the disassembly of cellular wall polysaccharides in the presence of superoxide anion (O2(-)), hydrogen peroxide (H2O2) or hydroxyl radical (OH) and their scavengers. The presence of OH accelerated significantly disassembly of cellular wall polysaccharides in terms of the increase in contents of total sugars released and uronic acid, and the decrease in molecular mass of soluble polysaccharides, using gel permeation chromatography. However, the treatment with H2O2 or O2(-) showed no significant effect on the disassembly of cellular wall polysaccharides. Furthermore, the degradation of the de-esterified AEIR was more susceptible to OH attack than the esterified AEIR. In addition, the effect of OH could be inhibited in the presence of OH scavenger. This study suggests that disassembly of cellular wall polysaccharides could be initiated by OH as the solublisation of the polysaccharides increased, which, in turn, accelerated fruit softening. Copyright © 2008 Elsevier Ltd. All rights reserved.

  12. Horseradish Peroxidase-Encapsulated Hollow Silica Nanospheres for Intracellular Sensing of Reactive Oxygen Species

    Science.gov (United States)

    Chen, Hsin-Yi; Wu, Si-Han; Chen, Chien-Tsu; Chen, Yi-Ping; Chang, Feng-Peng; Chien, Fan-Ching; Mou, Chung-Yuan

    2018-04-01

    Reactive oxygen species (ROS) have crucial roles in cell signaling and homeostasis. Overproduction of ROS can induce oxidative damage to various biomolecules and cellular structures. Therefore, developing an approach capable of monitoring and quantifying ROS in living cells is significant for physiology and clinical diagnoses. Some cell-permeable fluorogenic probes developed are useful for the detection of ROS while in conjunction with horseradish peroxidase (HRP). Their intracellular scenario is however hindered by the membrane-impermeable property of enzymes. Herein, a new approach for intracellular sensing of ROS by using horseradish peroxidase-encapsulated hollow silica nanospheres (designated HRP@HSNs), with satisfactory catalytic activity, cell membrane permeability, and biocompatibility, was prepared via a microemulsion method. These HRP@HSNs, combined with selective probes or targeting ligands, could be foreseen as ROS-detecting tools in specific organelles or cell types. As such, dihydrorhodamine 123-coupled HRP@HSNs were used for the qualitative and semi-quantitative analysis of physiological H2O2 levels in activated RAW 264.7 macrophages. We envision that this HSNs encapsulating active enzymes can be conjugated with selective probes and targeting ligands to detect ROS in specific organelles or cell types of interest.

  13. Salinomycin induces autophagy in colon and breast cancer cells with concomitant generation of reactive oxygen species.

    Directory of Open Access Journals (Sweden)

    Berlinda Verdoodt

    Full Text Available BACKGROUND: Salinomycin is a polyether ionophore antibiotic that has recently been shown to induce cell death in human cancer cells displaying multiple mechanisms of drug resistance. The underlying mechanisms leading to cell death after salinomycin treatment have not been well characterized. We therefore investigated the role of salinomycin in caspase dependent and independent cell death in colon cancer (SW480, SW620, RKO and breast cancer cell lines (MCF-7, T47D, MDA-MB-453. METHODOLOGY/PRINCIPAL FINDINGS: We detected features of apoptosis in all cell lines tested, but the executor caspases 3 and 7 were only strongly activated in RKO and MDA-MB-453 cells. MCF-7 and SW620 cells instead presented features of autophagy such as cytoplasmic vacuolization and LC3 processing. Caspase proficient cell lines activated autophagy at lower salinomycin concentrations and before the onset of caspase activation. Salinomycin also led to the formation of reactive oxygen species (ROS eliciting JNK activation and induction of the transcription factor JUN. Salinomycin mediated cell death could be partially inhibited by the free radical scavenger N-acetyl-cysteine, implicating ROS formation in the mechanism of salinomycin toxicity. CONCLUSIONS: Our data indicate that, in addition to its previously reported induction of caspase dependent apoptosis, the initiation of autophagy is an important and early effect of salinomycin in tumor cells.

  14. Reactive oxygen species signaling and stomatal movement: Current updates and future perspectives

    Directory of Open Access Journals (Sweden)

    Rachana Singh

    2017-04-01

    Full Text Available Reactive oxygen species (ROS, a by-product of aerobic metabolism were initially studied in context to their damaging effect but recent decades witnessed significant advancements in understanding the role of ROS as signaling molecules. Contrary to earlier views, it is becoming evident that ROS production is not necessarily a symptom of cellular dysfunction but it might represent a necessary signal in adjusting the cellular machinery according to the altered conditions. Stomatal movement is controlled by multifaceted signaling network in response to endogenous and environmental signals. Furthermore, the stomatal aperture is regulated by a coordinated action of signaling proteins, ROS-generating enzymes, and downstream executors like transporters, ion pumps, plasma membrane channels, which control the turgor pressure of the guard cell. The earliest hallmarks of stomatal closure are ROS accumulation in the apoplast and chloroplasts and thereafter, there is a successive increase in cytoplasmic Ca2+ level which rules the multiple kinases activity that in turn regulates the activity of ROS-generating enzymes and various ion channels. In addition, ROS also regulate the action of multiple proteins directly by oxidative post translational modifications to adjust guard cell signaling. Notwithstanding, an active progress has been made with ROS signaling mechanism but the regulatory action for ROS signaling processes in stomatal movement is still fragmentary. Therefore, keeping in view the above facts, in this mini review the basic concepts and role of ROS signaling in the stomatal movement have been presented comprehensively along with recent highlights.

  15. Reactive Oxygen Species and Antioxidant in Seminal Plasma and Their Impact on Male Fertility

    Directory of Open Access Journals (Sweden)

    Mohammad Eid Hammadeh

    2009-01-01

    Full Text Available Spermatozoa generate reactive oxygen species (ROS in physiological amounts, which play arole in sperm functions during sperm capacitation, acrosome reaction (AR, and oocyte fusion. Inaddition, damaged sperm are likely to be the source of ROS. The most important ROS producedby human sperm are hydrogen peroxide, superoxide anion and hydroxyl radicals. Besides, humanseminal plasma and sperm possess an antioxidant system to scavenge ROS and prevent ROS relatedcellular damage. Under normal circumstances, there is an appropriate balance between oxidants andantioxidants. A shift in the levels of ROS towards pro-oxidants in semen can induce oxidative stress(OS on spermatozoa.Male infertility is associated with increased ROS and decreased total antioxidant activity in theseminal plasma. ROS induce nuclear DNA strand breaks. Besides, due to a high polyunsaturatedfatty acid content human sperm plasma membranes are highly sensitive to ROS induced lipidperoxidation thus decreasing membrane fluidity. This will result in increased lipid peroxidation(LPO, decreased sperm motility, viability, function and ultimately lead to infertility. The protectiveaction of antioxidants against the deleterious effect of ROS on cellular lipids, proteins and DNA hasbeen supported by several scientific studies.The purpose of the present review is to address the possible relationship between ROS andantioxidants production in seminal plasma, and the role they may play in influencing the outcomeof assisted reproductive technology (ART.

  16. Quorum sensing circuit and reactive oxygen species resistance in Deinococcus sp.

    Science.gov (United States)

    Fernandez-Bunster, G; Gonzalez, C; Barros, J; Martinez, M

    2012-12-01

    Genus Deinococcus is characterized by an increased resistance toward reactive oxygen species (ROS). The chromosome of five strains belonging to this genus has been sequenced and the presence of a luxS-like gene was deduced from their genome sequences. The aim of this study was to assess if a complete QS circuit is present in Deinococcus sp. and if this QS is associated with ROS. Primers for searching luxS-like gene and the putative receptor gene, namely ai2R, were designed. AI-2 signal production was evaluated by luminescence analysis using Vibrio harveyi BB170 as reporter strain. AI-2 signal was also evaluated by competitive assays using cinnamaldehyde, ascorbic acid, and 3-mercaptopropionic acid as interfering molecules. Potassium tellurite and metronidazole were used as oxidative stressors. A luxS-like gene as well as an ai2R gene was detected in strain UDEC-P1 by PCR. Cell-free supernatant of strain UDEC-P1 culture induced luminescence in V. harveyi BB170, and this property was inhibited with the three interfering molecules. The oxidative stressors metronidazole and potassium tellurite decreased Deinococcus sp. viability, but increased luminescence of the reporter strain. The results demonstrate that both a functional luxS-like gene and a putative receptor for AI-2 signal are present in Deinococcus sp. strain UDEC-P1. This finding also suggests that a complete QS circuit is present in this genus, which could be related to oxidative stress.

  17. Alpha-synuclein induces lysosomal rupture and cathepsin dependent reactive oxygen species following endocytosis.

    Directory of Open Access Journals (Sweden)

    David Freeman

    Full Text Available α-synuclein dysregulation is a critical aspect of Parkinson's disease pathology. Recent studies have observed that α-synuclein aggregates are cytotoxic to cells in culture and that this toxicity can be spread between cells. However, the molecular mechanisms governing this cytotoxicity and spread are poorly characterized. Recent studies of viruses and bacteria, which achieve their cytoplasmic entry by rupturing intracellular vesicles, have utilized the redistribution of galectin proteins as a tool to measure vesicle rupture by these organisms. Using this approach, we demonstrate that α-synuclein aggregates can induce the rupture of lysosomes following their endocytosis in neuronal cell lines. This rupture can be induced by the addition of α-synuclein aggregates directly into cells as well as by cell-to-cell transfer of α-synuclein. We also observe that lysosomal rupture by α-synuclein induces a cathepsin B dependent increase in reactive oxygen species (ROS in target cells. Finally, we observe that α-synuclein aggregates can induce inflammasome activation in THP-1 cells. Lysosomal rupture is known to induce mitochondrial dysfunction and inflammation, both of which are well established aspects of Parkinson's disease, thus connecting these aspects of Parkinson's disease to the propagation of α-synuclein pathology in cells.

  18. Sibutramine provokes apoptosis of aortic endothelial cells through altered production of reactive oxygen and nitrogen species.

    Science.gov (United States)

    Morikawa, Yoshifumi; Shibata, Akinobu; Okumura, Naoko; Ikari, Akira; Sasajima, Yasuhide; Suenami, Koichi; Sato, Kiyohito; Takekoshi, Yuji; El-Kabbani, Ossama; Matsunaga, Toshiyuki

    2017-01-01

    Overdose administration of sibutramine, a serotonin-noradrenalin reuptake inhibitor, is considered to elicit severe side effects including hypertension, whose pathogenic mechanism remains unclear. Here, we found that 48-h incubation with >10μM sibutramine provokes apoptosis of human aortic endothelial (HAE) cells. Treatment with the lethal concentration of sibutramine facilitated production of reactive oxygen species (ROS), altered expression of endoplasmic reticulum stress response genes (heat shock protein 70 and C/EBP homologous protein), and inactivated 26S proteasome-based proteolysis. The treatment also decreased cellular level of nitric oxide (NO) through lowering of expression and activity of endothelial NO synthase. These results suggest that ROS production and depletion of NO are crucial events in the apoptotic mechanism and may be linked to the pathogenesis of vasoconstriction elicited by the drug. Compared to sibutramine, its metabolites (N-desmethylsibutramine and N-didesmethylsibutramine) were much less cytotoxic to HAE cells, which hardly metabolized sibutramine. In contrast, both the drug and metabolites showed low cytotoxicity to hepatic HepG2 cells with high metabolic potency and expression of cytochrome P450 (CYP) 3A4. The cytotoxicity of sibutramine to HepG2 and Chang Liver cells was remarkably augmented by inhibition and knockdown of CYP3A4. This study also suggests an inverse relationship between sibutramine cytotoxicity and CYP3A4-mediated metabolism into the N-desmethyl metabolites. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. α-Syntrophin stabilizes catalase to reduce endogenous reactive oxygen species levels during myoblast differentiation.

    Science.gov (United States)

    Moon, Jae Yun; Choi, Su Jin; Heo, Cheol Ho; Kim, Hwan Myung; Kim, Hye Sun

    2017-07-01

    α-Syntrophin is a component of the dystrophin-glycoprotein complex that interacts with various intracellular signaling proteins in muscle cells. The α-syntrophin knock-down C2 cell line (SNKD), established by infecting lentivirus particles with α-syntrophin shRNA, is characterized by a defect in terminal differentiation and increase in cell death. Since myoblast differentiation is accompanied by intensive mitochondrial biogenesis, the generation of intracellular reactive oxygen species (ROS) is also increased during myogenesis. Two-photon microscopy imaging showed that excessive intracellular ROS accumulated during the differentiation of SNKD cells as compared with control cells. The formation of 4-hydroxynonenal adduct, a byproduct of lipid peroxidation during oxidative stress, significantly increased in differentiated SNKD myotubes and was dramatically reduced by epigallocatechin-3-gallate, a well-known ROS scavenger. Among antioxidant enzymes, catalase was significantly decreased during differentiation of SNKD cells without changes at the mRNA level. Of interest was the finding that the degradation of catalase was rescued by MG132, a proteasome inhibitor, in the SNKD cells. This study demonstrates a novel function of α-syntrophin. This protein plays an important role in the regulation of oxidative stress from endogenously generated ROS during myoblast differentiation by modulating the protein stability of catalase. © 2017 Federation of European Biochemical Societies.

  20. Anxiety-induced plasma norepinephrine augmentation increases reactive oxygen species formation by monocytes in essential hypertension.

    Science.gov (United States)

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

    2006-06-01

    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. In Protocol 1, a cross-sectional study was performed in 146 hypertensive patients to evaluate whether anxiety and depression affect BP and ROS formation by MNC through increasing plasma catecholamines. In Protocol 2, a 6-month randomized controlled trial using a subtherapeutic dose of the alpha(1)-adrenergic receptor antagonist doxazosin (1 mg/day) versus placebo in 86 patients with essential hypertension was performed to determine whether the increase in ROS formation by MNC was independent of BP. In Protocol 1, a significant relationship was observed between the following: trait anxiety and plasma norepinephrine (r = 0.32, P anxiety may increase plasma norepinephrine and increase ROS formation by MNC independent of BP in hypertensive patients.

  1. Nicorandil prevents sirolimus-induced production of reactive oxygen species, endothelial dysfunction, and thrombus formation

    Directory of Open Access Journals (Sweden)

    Ken Aizawa

    2015-03-01

    Full Text Available Sirolimus (SRL is widely used to prevent restenosis after percutaneous coronary intervention. However, its beneficial effect is hampered by complications of thrombosis. Several studies imply that reactive oxygen species (ROS play a critical role in endothelial dysfunction and thrombus formation. The present study investigated the protective effect of nicorandil (NIC, an anti-angina agent, on SRL-associated thrombosis. In human coronary artery endothelial cells (HCAECs, SRL stimulated ROS production, which was prevented by co-treatment with NIC. The preventive effect of NIC on ROS was abolished by 5-hydroxydecanoate but not by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one. NIC also inhibited SRL-induced up-regulation of NADPH oxidase subunit p22phox mRNA. Co-treatment with NIC and SRL significantly up-regulated superoxide dismutase 2. NIC treatment significantly improved SRL-induced decrease in viability of HCAECs. The functional relevance of the preventive effects of NIC on SRL-induced ROS production and impairment of endothelial viability was investigated in a mouse model of thrombosis. Pretreatment with NIC inhibited the SRL-induced acceleration of FeCl3-initiated thrombus formation and ROS production in the testicular arteries of mice. In conclusion, NIC prevented SRL-induced thrombus formation, presumably due to the reduction of ROS and to endothelial protection. The therapeutic efficacy of NIC could represent an additional option in the prevention of SRL-related thrombosis.

  2. Controllable generation of reactive oxygen species by femtosecond-laser irradiation

    International Nuclear Information System (INIS)

    Yan, Wei; He, Hao; Wang, Yintao; Wang, Yisen; Hu, Minglie; Wang, Chingyue

    2014-01-01

    Femtosecond lasers have been advancing Biophotonics research in the past two decades with multiphoton microscopy, microsurgery, and photodynamic therapy. Nevertheless, laser irradiation is identified to bring photodamage to cells via reactive oxygen species (ROS) generation with unclear mechanism. Meanwhile, currently in biological researches, there is no effective method to provide controllable ROS production precisely, which originally is leaked from mitochondria during respiration and plays a key role in a lot of important cellular processes and cellular signaling pathways. In this study, we show the process of how the tightly focused femtosecond-laser induces ROS generation solely in mitochondria at the very beginning and then release to cytosol if the stimulus is intense enough. At certain weak power levels, the laser pulses induce merely moderate Ca 2+ release but this is necessary for the laser to generate ROS in mitochondria. Cellular original ROS are also involved with a small contribution. When the power is above a threshold, ROS are then released to cytosol, indicating photodamage overwhelming cellular repair ability. The mechanisms in those two cases are quite different. Those results clarify parts of the mechanism in laser-induced ROS generation. Hence, it is possible to further this optical scheme to provide controllable ROS generation for ROS-related biological researches including mitochondrial diseases and aging

  3. (±)-2-Chloropropionic acid elevates reactive oxygen species formation in human neutrophil granulocytes

    International Nuclear Information System (INIS)

    Aam, B.B.; Fonnum, F.

    2006-01-01

    (±)-2-Chloropropionic acid (2-CPA) is a neurotoxic compound which kills cerebellar granule cells in vivo, and makes cerebellar granule cells in vitro produce reactive oxygen species (ROS). We have studied the effect of 2-CPA on ROS formation in human neutrophil granulocytes in vitro. We found an increased formation of ROS after 2-CPA exposure using three different methods; the fluorescent probe DCFH-DA and the chemiluminescent probes lucigenin and luminol. Four different inhibitors of ROS formation were tested on the cells in combination with 2-CPA to characterize the signalling pathways. The spin-trap s-PBN, the ERK1/2 inhibitor U0126 and the antioxidant Vitamin E inhibited the 2-CPA-induced ROS formation completely, while the mitochondrial transition permeability pore blocker cyclosporine A inhibited the ROS formation partly. We also found that 2-CPA induced an increased nitric oxide production in the cells by using the Griess reagent. The level of reduced glutathione, measured with the DTNB assay, was decreased after exposure to high concentrations of 2-CPA. Western blotting analysis showed that 2-CPA exposure led to an elevated phosphorylation of ERK MAP kinase. This phosphorylation was inhibited by U0126. Based on these experiments it seems like the mechanisms for 2-CPA induced toxicity involves ROS formation and is similar in neutrophil granulocytes as earlier shown in cerebellar granule cells. This also implies that 2-CPA may be immunotoxic

  4. The Effect of Reactive Oxygen Species on Embryo Quality in IVF.

    Science.gov (United States)

    Siristatidis, Charalampos; Vogiatzi, Paraskevi; Varounis, Christos; Askoxylaki, Marily; Chrelias, Charalampos; Papantoniou, Nikolaos

    2016-01-01

    BACKROUND/AIM: Reactive oxygen species (ROS) are involved in critical biological processes in human reproduction. The aim of this study was to evaluate the association of embryo quality following in vitro fertilization (IVF), with ROS levels in the serum and follicular fluid (FF). Eighty-five participants underwent ovarian stimulation and IVF; ROS levels were measured in blood samples on the day of oocyte retrieval and in the FF from follicular aspirates using enzyme-linked immunosorbent assay. These values were associated with the quality of embryos generated. Univariable zero-inflated Poisson model revealed that ROS levels at both oocyte retrieval and in FF were not associated with the number of grade I, II, III and IV embryos (p>0.05). Age, body mass index, stimulation protocol and smoking status were not associated with the number of embryos of any grade (p>0.05). Neither ROS levels in serum nor in FF are associated with the quality of embryos produced following IVF. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  5. Alpha-particles microbeam irradiation: impact of reactive oxygen species in bystander effect

    International Nuclear Information System (INIS)

    Hanot, M.

    2008-11-01

    Ionizing radiation-induced bystander effects arise in bystander cells that receive signals from directly irradiated cells. To date, free radicals are believed to play an active role in the bystander response, but this is incompletely characterized. To mark temporal and spatial impacts of bystander effect, we employed a precise α-particle microbeam to target a small fraction of sub-confluent osteoblastic cell cultures (MC3T3-E1). We identified the cellular membrane and mitochondria like two distinct places generating reactive oxygen species. The global oxidative stress observed after irradiation was significantly attenuated after filipin treatment, evidencing the pivotal role of membrane in MC3T3-E1 cells bystander response. To determine impact of bystander effect at a cell level, cellular consequences of this membrane-dependant bystander effect were then investigated. A variable fraction of the cell population (10 to 100%) was individually targeted. In this case, mitotic death and micronuclei yield both increased in bystander cells as well as in targeted cells demonstrating a role of bystander signals between irradiated cells in an autocrine or paracrine manner. Our results indicate a complex interaction of direct irradiation and bystander signals that lead to a membrane-dependant amplification of cell responses. (author)

  6. Reactive oxygen species dynamics in roots of salt sensitive and salt tolerant cultivars of rice.

    Science.gov (United States)

    Saini, Shivani; Kaur, Navdeep; Pati, Pratap Kumar

    2018-06-01

    Salinity stress is one of the major constraints for growth and survival of plants that affects rice productivity worldwide. Hence, in the present study, roots of two contrasting salinity sensitive cultivars, IR64 (IR64, salt sensitive) and Luna Suvarna (LS, salt tolerant) were compared with regard to the levels of reactive oxygen species (ROS) to derive clues for their differential salt stress adaptation mechanisms. In our investigation, the tolerant cultivar exhibited longer primary roots, more lateral roots, higher root number leading to increased root biomass, with respect to IR64. It was observed that LS roots maintained higher level of H 2 O 2 in comparison to IR64. The activities of various enzymes involved in enzymatic antioxidant defense mechanism (SOD, CAT, GPX, DHAR and MDHAR) were found to be greater in LS roots. Further, the higher transcript level accumulation of genes encoding ROS generating (RbohA, RbohD and RbohE) and scavenging enzymes (Fe-SOD, Chloroplastic Cu/Zn-SOD, CAT and DHAR) were noticed in the roots of tolerant cultivar, LS. Moreover, the content of other stress markers such as total protein and proline were also elevated in LS roots. While, the expression of proline biosynthesis gene (P5CS) and proline catabolism gene (PDH) was observed to be lower in LS. Copyright © 2018. Published by Elsevier Inc.

  7. Phenolic extract of Dialium guineense pulp enhances reactive oxygen species detoxification in aflatoxin B₁ hepatocarcinogenesis.

    Science.gov (United States)

    Adeleye, Abdulwasiu O; Ajiboye, Taofeek O; Iliasu, Ganiyat A; Abdussalam, Folakemi A; Balogun, Abdulazeez; Ojewuyi, Oluwayemisi B; Yakubu, Musa T

    2014-08-01

    This study investigated the effect of Dialium guineense pulp phenolic extract on aflatoxin B1 (AFB1)-induced oxidative imbalance in rat liver. Reactive oxygen species (ROS) scavenging potentials of free and bound phenolic extract of D. guineense (0.2-1.0 mg/mL) were investigated in vitro using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide ion (O2(-)), hydrogen peroxide (H2O2), hydroxyl radical, and ferric ion reducing system. In the in vivo study, 35 animals were randomized into seven groups of five rats each. Free and bound phenolic extract (1 mg/mL) produced 66.42% and 93.08%, 57.1% and 86.0%, 62.0% and 90.05%, and 60.11% and 72.37% scavenging effect on DPPH radical, O2(-) radical, H2O2, and hydroxyl radical, while ferric ion was significantly reduced. An AFB1-mediated decrease in the activities of ROS detoxifying enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glucose 6 phosphate dehydrogenase) was significantly attenuated (P<.05). AFB1-mediated elevation in the concentrations of oxidative stress biomarkers; malondialdehyde, conjugated dienes, lipid hydroperoxides, protein carbonyl, and percentage DNA fragmentation were significantly lowered by D. guineense phenolic extract (P<.05). Overall, the in vitro and in vivo effects suggest that D. guineense phenolic extract elicited ROS scavenging and detoxification potentials, as well as the capability of preventing lipid peroxidation, protein oxidation, and DNA fragmentation.

  8. The Role of Mitochondrial Reactive Oxygen Species in Cardiovascular Injury and Protective Strategies

    Directory of Open Access Journals (Sweden)

    Danina M. Muntean

    2016-01-01

    Full Text Available Ischaemia/reperfusion (I/R injury of the heart represents a major health burden mainly associated with acute coronary syndromes. While timely coronary reperfusion has become the established routine therapy in patients with ST-elevation myocardial infarction, the restoration of blood flow into the previously ischaemic area is always accompanied by myocardial injury. The central mechanism involved in this phenomenon is represented by the excessive generation of reactive oxygen species (ROS. Besides their harmful role when highly generated during early reperfusion, minimal ROS formation during ischaemia and/or at reperfusion is critical for the redox signaling of cardioprotection. In the past decades, mitochondria have emerged as the major source of ROS as well as a critical target for cardioprotective strategies at reperfusion. Mitochondria dysfunction associated with I/R myocardial injury is further described and ultimately analyzed with respect to its role as source of both deleterious and beneficial ROS. Furthermore, the contribution of ROS in the highly investigated field of conditioning strategies is analyzed. In the end, the vascular sources of mitochondria-derived ROS are briefly reviewed.

  9. Glycidamide inhibits progesterone production through reactive oxygen species-induced apoptosis in R2C Rat Leydig Cells.

    Science.gov (United States)

    Li, Mingwei; Sun, Jianxia; Zou, Feiyan; Bai, Shun; Jiang, Xinwei; Jiao, Rui; Ou, Shiyi; Zhang, Hui; Su, Zhijian; Huang, Yadong; Bai, Weibin

    2017-10-01

    The food contaminant acrylamide (AA) is usually recognized as a probable human carcinogen. In addition, AA has also been found able to induce male infertility in animals. Interestingly, resent research work revealed that the toxic effect of AA on the ability of male reproduction in vivo may due to glycidamide (GA) which is the metabolite of AA. In this study, R2C Leydig cells was used to investigate the toxic effects of GA on progesterone production. GA caused dose-dependent inhibition on the cell growth, with IC 25 , IC 50, and IC 75 values found at 0.635, 0.872, and 1.198 mM, respectively. The results of single cell gel/Comet assay showed that GA significantly induced early-phase cell apoptosis, reduced progesterone production, as well as decreasing the protein expression of steroidogenic acute regulatory (StAR) in R2C cells. Furthermore, GA induced overproduction of intracellular reactive oxygen species (ROS), upregulated Bax expression, decreased mitochondrial membrane potential, and triggered mitochondria-mediated cell apoptosis. Consequently, the downstream effector caspase-3 was activated, resulting in Leydig cells apoptosis. Overall, our results showed that GA could damage R2C Leydig cells by the lesion of the ability of progesterone genesis and inducing cells apoptosis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Pentagalloyl glucose increases elastin deposition, decreases reactive oxygen species and matrix metalloproteinase activity in pulmonary fibroblasts under inflammatory conditions.

    Science.gov (United States)

    Parasaram, Vaideesh; Nosoudi, Nasim; Chowdhury, Aniqa; Vyavahare, Naren

    2018-04-30

    Emphysema is characterized by degradation of lung alveoli that leads to poor airflow in lungs. Irreversible elastic fiber degradation by matrix metalloproteinases (MMPs) and reactive oxygen species (ROS) activity leads to loss of elasticity and drives the progression of this disease. We investigated if a polyphenol, pentagalloyl glucose (PGG) can increase elastin production in pulmonary fibroblasts. We also studied the effect of PGG treatment in reducing MMP activity and ROS levels in cells. We exposed rat pulmonary fibroblasts to two different types of inflammatory environments i.e., tumor necrosis factor-α (TNF-α) and cigarette smoke extract (CSE) to mimic the disease. Parameters like lysyl oxidase (LOX) and elastin gene expression, MMP-9 activity in the medium, lysyl oxidase (LOX) activity and ROS levels were studied to assess the effect of PGG on pulmonary fibroblasts. CSE inhibited lysyl oxidase (LOX) enzyme activity that resulted in a decreased elastin formation. Similarly, TNF-α treated cells showed less elastin in the cell layers. Both these agents caused increase in MMP activity and ROS levels in cells. However, when supplemented with PGG treatment along with these two inflammatory agents, we saw a significant increase in elastin deposition, reduction in both MMP activity and ROS levels. Thus PGG, which has anti-inflammatory, anti-oxidant properties coupled with its ability to aid in elastic fiber formation, can be a multifunctional drug to potentially arrest the progression of emphysema. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. The effects of quercetin towards reactive oxygen species levels and glutathione in Toxoplasma gondii profilin-exposed adipocytes in vitro

    Directory of Open Access Journals (Sweden)

    Yulia D.S.

    2018-04-01

    Full Text Available Toxoplasma gondii (T. gondii has been found to potentially cause adipocyte dysfunction by activating the inflammatory pathways through its profilin. In response to inflammation, adipocytes produce Reactive Oxygen Species (ROS. To scavenge ROS, endogenous or exogenous antioxidants are required. Glutathione (GSH is one of enzimatic antioxidant that abundant in all of body cells. Quercetin, an exogenous antioxidant, can be widely found in natural products. This research aims to explore the effects of quercetin towards ROS and GSH stimulated from T. gondii profilin-exposed adipocytes. To achieve this, adipocytes were exposed to 20 µM T. gondii profilin and treated with four doses of quercetin; 31.25, 62.5, 125, and 250 µM. The results showed that quercetin significantly reduced the ROS levels (p <0,001 and significantly increased GSH (p <0,001 in T. gondii profilin-exposed adipocytes compared to untreated cells, with an effective dose of 62.5µM. This study implies that quercetin might be a promising candidate for development of antioxidant treatment interventions to prevent toxoplasmosis-mediated adipocytopathy.

  12. Phenethyl isothiocyanate inhibits growth of human chronic myeloid leukemia K562 cells via reactive oxygen species generation and caspases.

    Science.gov (United States)

    Wang, Yating; Wei, Sixi; Wang, Jishi; Fang, Qin; Chai, Qixiang

    2014-07-01

    Phenethyl isothiocyanate (PEITC), a potential cancer chemopreventive constituent of cruciferous vegetables, including watercress, has been reported to inhibit cancer cell growth by arresting the cell cycle and inducing apoptosis in various human cancer cell models. However, the role of PEITC in the inhibition of human chronic myeloid leukemia (CML) K562 cell growth and its underlying mechanisms have yet to be elucidated. In the present study, PEITC was found to induce cell death through the induction of reactive oxygen species (ROS) stress and oxidative damage. Heme oxygenase‑1 (HO‑1), which participates in the development of numerous tumors and the sensitivity of these tumors to chemotherapeutic drugs, plays a protective role by modulating oxidative injury. Therefore, the present study assessed the inhibitory effect of PEITC on K562 cells and whether HO‑1 facilitated cell apoptosis and ROS generation. PEITC was found to suppress cell growth and cause apoptosis by promoting Fas and Fas ligand expression, increasing ROS generation and by the successive release of cytochrome c as well as the activation of caspase‑9 and caspase‑3. PEITC was also combined with the HO‑1 inhibitor zinc protoporphyrin IX and the inducer hemin to assess whether HO‑1 determines cell survival and ROS generation. The results of the present study suggest that PEITC may be a potential anti‑tumor compound for CML therapy, and that HO‑1 has a critical function in PEITC‑induced apoptosis and ROS generation.

  13. Antimony trichloride induces a loss of cell viability via reactive oxygen species-dependent autophagy in A549 cells.

    Science.gov (United States)

    Zhao, Xinyuan; Xing, Fengjun; Cong, Yewen; Zhuang, Yin; Han, Muxi; Wu, Zhiqiang; Yu, Shali; Wei, Haiyan; Wang, Xiaoke; Chen, Gang

    2017-12-01

    Antimony (Sb) is one of the most prevalent heavy metals and frequently leads to biological toxicity. Although autophagy is believed to be involved in metal-associated cytotoxicity, there is no evidence of its involvement following exposure. Moreover, the underlying mechanism of autophagy remains unclear. In this study, treatment with antimony trichloride caused autophagy in a dose- and time-dependent manner in A549 cells but did not affect the level of Atg5 or Atg7 mRNA expression. Furthermore, Sb enhanced autophagic flux while upregulating p62 gene and protein levels. The classic mechanistic target of rapamycin (mTOR) pathway is not involved in Sb-induced autophagy. However, Sb-induced autophagy and the upregulation of p62 were inhibited by treatment with the antioxidant N-acetylcysteine (NAC). Subsequent analyses demonstrated that the inhibition of autophagy protected A549 cells from a loss of cell viability, while the activation of autophagy by rapamycin had the opposite effect. These data suggest that reactive oxygen species-dependent autophagy mediates Sb-stimulated cell viability loss in A549 cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Reactive oxygen species-mediated DNA damage and apoptosis in human skin epidermal cells after exposure to nickel nanoparticles.

    Science.gov (United States)

    Alarifi, Saud; Ali, Daoud; Alakhtani, Saad; Al Suhaibani, Entissar S; Al-Qahtani, Ahmed A

    2014-01-01

    Nickel nanoparticles (NiNPs) are increasingly used in various applications due to their unique properties. However, there is little information concerning the toxicity of NiNPs in the human skin cell (A431). The present study was designed to investigate the cytotoxicity, apoptosis, and DNA damage due to NiNPs in A431 cells. A cellular proliferative capacity test showed that NiNPs induce significant cytotoxicity in a dose- and time-dependent manner. NiNPs were also found to induce oxidative stress evidenced by the generation of reactive oxygen species (ROS) and depletion of glutathione (GSH). Further, co-treatment with the antioxidant N-acetylcysteine (NAC) mitigated the ROS generation due to NiNPs, suggesting the potential mechanism of oxidative stress. NiNPs also induced significant elevation of lipid peroxidation, catalase, and superoxide dismutase and caspase-3 activity in A431 cells. In addition, NAC suppressed NiNP-induced caspase-3 activity. DNA fragmentation analysis using the comet assay showed that the NiNPs cause genotoxicity in a dose- and time-dependent manner. Therefore, the study points out the capability of the NiNPs to induce oxidative stress resulting in apoptosis and genotoxicity. This study warrants more careful assessment of NiNPs before their industrial applications.

  15. Induction of Apoptosis in Human Multiple Myeloma Cell Lines by Ebselen via Enhancing the Endogenous Reactive Oxygen Species Production

    Directory of Open Access Journals (Sweden)

    Liang Zhang

    2014-01-01

    Full Text Available Ebselen a selenoorganic compound showing glutathione peroxidase like activity is an anti-inflammatory and antioxidative agent. Its cytoprotective activity has been investigated in recent years. However, experimental evidence also shows that ebselen causes cell death in several cancer cell types whose mechanism has not yet been elucidated. In this study, we examined the effect of ebselen on multiple myeloma (MM cell lines in vitro. The results showed that ebselen significantly enhanced the production of reactive oxygen species (ROS accompanied by cell viability decrease and apoptosis rate increase. Further studies revealed that ebselen can induce Bax redistribution from the cytosol to mitochondria leading to mitochondrial membrane potential ΔΨm changes and cytochrome C release from the mitochondria to cytosol. Furtherly, we found that exogenous addition of N-acetyl cysteine (NAC completely diminished the cell damage induced by ebselen. This result suggests that relatively high concentration of ebselen can induce MM cells apoptosis in culture by enhancing the production of endogenous ROS and triggering mitochondria mediated apoptotic pathway.

  16. Trichomonas vaginalis Induces SiHa Cell Apoptosis by NF-κB Inactivation via Reactive Oxygen Species

    Science.gov (United States)

    Quan, Juan-Hua; Kang, Byung-Hun; Yang, Jung-Bo; Rhee, Yun-Ee; Noh, Heung-Tae; Choi, In-Wook; Cha, Guang-Ho; Yuk, Jae-Min

    2017-01-01

    Trichomonas vaginalis induces apoptosis in host cells through various mechanisms; however, little is known about the relationship between apoptosis, reactive oxygen species (ROS), and NF-κB signaling pathways in the cervical mucosal epithelium. Here, we evaluated apoptotic events, ROS production, and NF-κB activity in T. vaginalis-treated cervical mucosal epithelial SiHa cells, with or without specific inhibitors, using fluorescence microscopy, DNA fragmentation assays, subcellular fractionation, western blotting, and luciferase reporter assay. SiHa cells treated with live T. vaginalis at a multiplicity of infection of 5 (MOI 5) for 4 h produced intracellular and mitochondrial ROS in a parasite-load-dependent manner. Incubation with T. vaginalis caused DNA fragmentation, cleavage of caspase 3 and PARP, and release of cytochrome c into the cytoplasm. T. vaginalis-treated SiHa cells showed transient early NF-κB p65 nuclear translocation, which dramatically dropped at 4 h after treatment. Suppression of NF-κB activity was dependent on parasite burden. However, treatment with the ROS scavenger, N-acetyl-C-cysteine (NAC), reversed the effect of T. vaginalis on apoptosis and NF-κB inactivation in SiHa cells. Taken together, T. vaginalis induces apoptosis in human cervical mucosal epithelial cells by parasite-dose-dependent ROS production through an NF-κB-regulated, mitochondria-mediated pathway. PMID:29410962

  17. Differential expression of islet glutaredoxin 1 and 5 with high reactive oxygen species production in a mouse model of diabesity.

    Science.gov (United States)

    Petry, Sebastian Friedrich; Sharifpanah, Fatemeh; Sauer, Heinrich; Linn, Thomas

    2017-01-01

    The onset and progression of diabetes mellitus type 2 is highly contingent on the amount of functional beta-cell mass. An underlying cause of beta-cell decay in diabetes is oxidative stress, which markedly affects the insulin producing pancreatic cells due to their poor antioxidant defence capacity. Consequently, disturbances of cellular redox signaling have been implicated to play a major role in beta-cell loss in diabetes mellitus type 2. There is evidence suggesting that the glutaredoxin (Grx) system exerts a protective role for pancreatic islets, but the exact mechanisms have not yet been elucidated. In this study, a mouse model for diabetes mellitus type 2 was used to gain further insight into the significance of Grx for the islets of Langerhans in the diabetic metabolism. We have observed distinct differences in the expression levels of Grx in pancreatic islets between obese, diabetic db mice and lean, non-diabetic controls. This finding is the first report about a decrease of Grx expression levels in pancreatic islets of diabetic mice which was accompanied by declining insulin secretion, increase of reactive oxygen species (ROS) production level, and cell cycle alterations. These data demonstrate the essential role of the Grx system for the beta-cell during metabolic stress which may provide a new target for diabetes mellitus type 2 treatment.

  18. Trichomonas vaginalis Induces SiHa Cell Apoptosis by NF-κB Inactivation via Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Juan-Hua Quan

    2017-01-01

    Full Text Available Trichomonas vaginalis induces apoptosis in host cells through various mechanisms; however, little is known about the relationship between apoptosis, reactive oxygen species (ROS, and NF-κB signaling pathways in the cervical mucosal epithelium. Here, we evaluated apoptotic events, ROS production, and NF-κB activity in T. vaginalis-treated cervical mucosal epithelial SiHa cells, with or without specific inhibitors, using fluorescence microscopy, DNA fragmentation assays, subcellular fractionation, western blotting, and luciferase reporter assay. SiHa cells treated with live T. vaginalis at a multiplicity of infection of 5 (MOI 5 for 4 h produced intracellular and mitochondrial ROS in a parasite-load-dependent manner. Incubation with T. vaginalis caused DNA fragmentation, cleavage of caspase 3 and PARP, and release of cytochrome c into the cytoplasm. T. vaginalis-treated SiHa cells showed transient early NF-κB p65 nuclear translocation, which dramatically dropped at 4 h after treatment. Suppression of NF-κB activity was dependent on parasite burden. However, treatment with the ROS scavenger, N-acetyl-C-cysteine (NAC, reversed the effect of T. vaginalis on apoptosis and NF-κB inactivation in SiHa cells. Taken together, T. vaginalis induces apoptosis in human cervical mucosal epithelial cells by parasite-dose-dependent ROS production through an NF-κB-regulated, mitochondria-mediated pathway.

  19. Induction of apoptosis in human multiple myeloma cell lines by ebselen via enhancing the endogenous reactive oxygen species production.

    Science.gov (United States)

    Zhang, Liang; Zhou, Liwei; Du, Jia; Li, Mengxia; Qian, Chengyuan; Cheng, Yi; Peng, Yang; Xie, Jiayin; Wang, Dong

    2014-01-01

    Ebselen a selenoorganic compound showing glutathione peroxidase like activity is an anti-inflammatory and antioxidative agent. Its cytoprotective activity has been investigated in recent years. However, experimental evidence also shows that ebselen causes cell death in several cancer cell types whose mechanism has not yet been elucidated. In this study, we examined the effect of ebselen on multiple myeloma (MM) cell lines in vitro. The results showed that ebselen significantly enhanced the production of reactive oxygen species (ROS) accompanied by cell viability decrease and apoptosis rate increase. Further studies revealed that ebselen can induce Bax redistribution from the cytosol to mitochondria leading to mitochondrial membrane potential ΔΨm changes and cytochrome C release from the mitochondria to cytosol. Furtherly, we found that exogenous addition of N-acetyl cysteine (NAC) completely diminished the cell damage induced by ebselen. This result suggests that relatively high concentration of ebselen can induce MM cells apoptosis in culture by enhancing the production of endogenous ROS and triggering mitochondria mediated apoptotic pathway.

  20. Exposure to ultrafine particles, intracellular production of reactive oxygen species in leukocytes and altered levels of endothelial progenitor cells

    International Nuclear Information System (INIS)

    Jantzen, Kim; Møller, Peter; Karottki, Dorina Gabriela; Olsen, Yulia; Bekö, Gabriel; Clausen, Geo; Hersoug, Lars-Georg; Loft, Steffen

    2016-01-01

    Exposure to particles in the fine and ultrafine size range has been linked to induction of low-grade systemic inflammation, oxidative stress and development of cardiovascular diseases. Declining levels of endothelial progenitor cells within systemic circulation have likewise been linked to progression of cardiovascular diseases. The objective was to determine if exposure to fine and ultrafine particles from indoor and outdoor sources, assessed by personal and residential indoor monitoring, is associated with altered levels of endothelial progenitor cells, and whether such effects are related to leukocyte-mediated oxidative stress. The study utilized a cross sectional design performed in 58 study participants from a larger cohort. Levels of circulating endothelial progenitor cells, defined as either late (CD34 + KDR + cells) or early (CD34 + CD133 + KDR + cells) subsets were measured using polychromatic flow cytometry. We additionally measured production of reactive oxygen species in leukocyte subsets (lymphocytes, monocytes and granulocytes) by flow cytometry using intracellular 2′,7′-dichlorofluoroscein. The measurements encompassed both basal levels of reactive oxygen species production and capacity for reactive oxygen species production for each leukocyte subset. We found that the late endothelial progenitor subset was negatively associated with levels of ultrafine particles measured within the participant residences and with reactive oxygen species production capacity in lymphocytes. Additionally, the early endothelial progenitor cell levels were positively associated with a personalised measure of ultrafine particle exposure and negatively associated with both basal and capacity for reactive oxygen species production in lymphocytes and granulocytes, respectively. Our results indicate that exposure to fine and ultrafine particles derived from indoor sources may have adverse effects on human vascular health.

  1. Impact of oxygen concentration on yields of DNA damages caused by ionizing radiation

    Czech Academy of Sciences Publication Activity Database

    Štěpán, Václav; Davídková, Marie

    2008-01-01

    Roč. 101, 012015 (2008), s. 1-4 ISSN 1742-6588. [Radiation Damage in Biomolecular Systems, RADAM'07. Dublin, 19.06.2007-22.06.2007] R&D Projects: GA ČR(CZ) GD202/05/H031; GA ČR GA202/05/2728 Institutional research plan: CEZ:AV0Z10480505 Keywords : radiation damage to DNA * oxygen concentration * theoretical modeling Subject RIV: BO - Biophysics

  2. NEBULAR WATER DEPLETION AS THE CAUSE OF JUPITER'S LOW OXYGEN ABUNDANCE

    International Nuclear Information System (INIS)

    Mousis, Olivier; Lunine, Jonathan I.; Madhusudhan, Nikku; Johnson, Torrence V.

    2012-01-01

    Motivated by recent spectroscopic observations suggesting that atmospheres of some extrasolar giant planets are carbon-rich, i.e., carbon/oxygen ratio (C/O) ≥ 1, we find that the whole set of compositional data for Jupiter is consistent with the hypothesis that it should be a carbon-rich giant planet. We show that the formation of Jupiter in the cold outer part of an oxygen-depleted disk (C/O ∼ 1) reproduces the measured Jovian elemental abundances at least as well as the hitherto canonical model of Jupiter formed in a disk of solar composition (C/O 0.54). The resulting O abundance in Jupiter's envelope is then moderately enriched by a factor of ∼2 × solar (instead of ∼7 × solar) and is found to be consistent with values predicted by thermochemical models of the atmosphere. That Jupiter formed in a disk with C/O ∼ 1 implies that water ice was heterogeneously distributed over several AU beyond the snow line in the primordial nebula and that the fraction of water contained in icy planetesimals was a strong function of their formation location and time. The Jovian oxygen abundance to be measured by NASA's Juno mission en route to Jupiter will provide a direct and strict test of our predictions.

  3. NEBULAR WATER DEPLETION AS THE CAUSE OF JUPITER'S LOW OXYGEN ABUNDANCE

    Energy Technology Data Exchange (ETDEWEB)

    Mousis, Olivier [Universite de Franche-Comte, Institut UTINAM, CNRS/INSU, UMR 6213, Observatoire des Sciences de l' Univers de Besancon (France); Lunine, Jonathan I. [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States); Madhusudhan, Nikku [Yale Center for Astronomy and Astrophysics, Department of Physics, Yale University, New Haven, CT 06511 (United States); Johnson, Torrence V., E-mail: olivier.mousis@obs-besancon.fr [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2012-05-20

    Motivated by recent spectroscopic observations suggesting that atmospheres of some extrasolar giant planets are carbon-rich, i.e., carbon/oxygen ratio (C/O) {>=} 1, we find that the whole set of compositional data for Jupiter is consistent with the hypothesis that it should be a carbon-rich giant planet. We show that the formation of Jupiter in the cold outer part of an oxygen-depleted disk (C/O {approx} 1) reproduces the measured Jovian elemental abundances at least as well as the hitherto canonical model of Jupiter formed in a disk of solar composition (C/O 0.54). The resulting O abundance in Jupiter's envelope is then moderately enriched by a factor of {approx}2 Multiplication-Sign solar (instead of {approx}7 Multiplication-Sign solar) and is found to be consistent with values predicted by thermochemical models of the atmosphere. That Jupiter formed in a disk with C/O {approx} 1 implies that water ice was heterogeneously distributed over several AU beyond the snow line in the primordial nebula and that the fraction of water contained in icy planetesimals was a strong function of their formation location and time. The Jovian oxygen abundance to be measured by NASA's Juno mission en route to Jupiter will provide a direct and strict test of our predictions.

  4. Asphyxiation death caused by oxygen-depleting cargo on a ship.

    Science.gov (United States)

    Sundal, Marjana Kjetland; Lilleng, Peer Kaare; Barane, Hans; Morild, Inge; Vevelstad, Merete

    2017-10-01

    The extreme danger associated with entering enclosed spaces loaded with oxygen-depleting organic cargo in ships and tanks is obviously underestimated, both among crew and management. We present a case report to highlight this occupational hazard and to increase the knowledge about the imperative precautions, in order to prevent future accidents. An experienced customs officer was found lifeless at the bottom of the unattended cargo hold on a ship loaded with woodchips. The oxygen content in the cargo atmosphere was below 2%, which is incompatible with life. Forensic autopsy revealed injuries related to the fall, and there were no positive toxicological findings in blood, lung or urine. Management and workers must be taught about the extreme rapidity of developing unconsciousness and asphyxiant death when entering enclosed spaces loaded with oxygen-depleting cargo. Even a single inhalation can result in unconsciousness and death. Dozens of annual deaths and severe injuries can easily be prevented if simple precautions are followed. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Reactive oxygen species on bone mineral density and mechanics in Cu,Zn superoxide dismutase (Sod1) knockout mice

    International Nuclear Information System (INIS)

    Smietana, Michael J.; Arruda, Ellen M.; Faulkner, John A.; Brooks, Susan V.; Larkin, Lisa M.

    2010-01-01

    Research highlights: → Reactive oxygen species (ROS) are considered to be a factor in the onset of a number of age-associated conditions, including loss of BMD. → Cu,Zn-superoxide dismutase (Sod1) deficient mice have increased ROS, reduced bone mineral density, decreased bending stiffness, and decreased strength compared to WT controls. → Increased ROS caused by the deficiency of Sod1, may be responsible for the changes in BMD and bone mechanics and therefore represent an appropriate model for studying mechanisms of age-associated bone loss. -- Abstract: Reactive oxygen species (ROS) play a role in a number of degenerative conditions including osteoporosis. Mice deficient in Cu,Zn-superoxide dismutase (Sod1) (Sod1 -/- mice) have elevated oxidative stress and decreased muscle mass and strength compared to wild-type mice (WT) and appear to have an accelerated muscular aging phenotype. Thus, Sod1 -/- mice may be a good model for evaluating the effects of free radical generation on diseases associated with aging. In this experiment, we tested the hypothesis that the structural integrity of bone as measured by bending stiffness (EI; N/mm 2 ) and strength (MPa) is diminished in Sod1 -/- compared to WT mice. Femurs were obtained from male and female WT and Sod1 -/- mice at 8 months of age and three-point bending tests were used to determine bending stiffness and strength. Bones were also analyzed for bone mineral density (BMD; mg/cc) using micro-computed tomography. Femurs were approximately equal in length across all groups, and there were no significant differences in BMD or EI with respect to gender in either genotype. Although male and female mice demonstrated similar properties within each genotype, Sod1 -/- mice exhibited lower BMD and EI of femurs from both males and females compared with gender matched WT mice. Strength of femurs was also lower in Sod1 -/- mice compared to WT as well as between genders. These data indicate that increased oxidative stress

  6. Toxicity of nano-TiO2 on algae and the site of reactive oxygen species production

    International Nuclear Information System (INIS)

    Li, Fengmin; Liang, Zhi; Zheng, Xiang; Zhao, Wei; Wu, Miao; Wang, Zhenyu

    2015-01-01

    Highlights: • The growth of two species of algae was inhibited under nano-TiO 2 exposure. • Oxidative stress was one of the mechanisms of toxicity of nano-TiO 2 on algae. • The site of ROS production was the electron transfer chain of chloroplast. - Abstract: Given the extensive use of nanomaterials, they may enter aquatic environments and harm the growth of algae, which are primary producers in an aquatic ecosystem. Thus, the balance of an aquatic ecosystem may be destroyed. In this study, Karenia brevis and Skeletonema costatum were exposed to nano-TiO 2 (anatase, average particle size of 5–10 nm, specific surface area of 210 ± 10 m 2 g −1 ) to assess the effects of nano-TiO 2 on algae. The findings of transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDX) and scanning electron microscopy (SEM) demonstrate aggregation of nano-TiO 2 in the algal suspension. Nano-TiO 2 was also found to be inside algal cells. The growth of the two species of algae was inhibited under nano-TiO 2 exposure. The 72 h EC 50 values of nano-TiO 2 to K. brevis and S. costatum were 10.69 and 7.37 mg L −1 , respectively. TEM showed that the cell membrane of K. brevis was destroyed and its organelles were almost undistinguished under nano-TiO 2 exposure. The malondialdehyde (MDA) contents of K. brevis and S. costatum significantly increased compared with those of the control (p < 0.05). Meanwhile, superoxide dismutase (SOD) and catalase activities (CAT) of K. brevis and S. costatum changed in different ways. The reactive oxygen species (ROS) levels in both species were significantly higher than those of the control (p < 0.05). The site of ROS production and accumulation in K. brevis and S. costatum under nano-TiO 2 exposure was explored with the addition of inhibitors of different electron transfer chains. This study indicated that nano-TiO 2 in algal suspensions inhibited the growth of K. brevis and S. costatum. This effect was attributed to oxidative

  7. Toxicity of nano-TiO{sub 2} on algae and the site of reactive oxygen species production

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fengmin, E-mail: lifengmin@ouc.edu.cn [Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Technology, Ocean University of China, Qingdao 266100 (China); Liang, Zhi [Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Technology, Ocean University of China, Qingdao 266100 (China); Zheng, Xiang, E-mail: zhengxiang7825@sina.com [School of Environment and Natural Resources, Renmin University of China, Beijing 100872 (China); Zhao, Wei; Wu, Miao; Wang, Zhenyu [Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Technology, Ocean University of China, Qingdao 266100 (China)

    2015-01-15

    Highlights: • The growth of two species of algae was inhibited under nano-TiO{sub 2} exposure. • Oxidative stress was one of the mechanisms of toxicity of nano-TiO{sub 2} on algae. • The site of ROS production was the electron transfer chain of chloroplast. - Abstract: Given the extensive use of nanomaterials, they may enter aquatic environments and harm the growth of algae, which are primary producers in an aquatic ecosystem. Thus, the balance of an aquatic ecosystem may be destroyed. In this study, Karenia brevis and Skeletonema costatum were exposed to nano-TiO{sub 2} (anatase, average particle size of 5–10 nm, specific surface area of 210 ± 10 m{sup 2} g{sup −1}) to assess the effects of nano-TiO{sub 2} on algae. The findings of transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDX) and scanning electron microscopy (SEM) demonstrate aggregation of nano-TiO{sub 2} in the algal suspension. Nano-TiO{sub 2} was also found to be inside algal cells. The growth of the two species of algae was inhibited under nano-TiO{sub 2} exposure. The 72 h EC{sub 50} values of nano-TiO{sub 2} to K. brevis and S. costatum were 10.69 and 7.37 mg L{sup −1}, respectively. TEM showed that the cell membrane of K. brevis was destroyed and its organelles were almost undistinguished under nano-TiO{sub 2} exposure. The malondialdehyde (MDA) contents of K. brevis and S. costatum significantly increased compared with those of the control (p < 0.05). Meanwhile, superoxide dismutase (SOD) and catalase activities (CAT) of K. brevis and S. costatum changed in different ways. The reactive oxygen species (ROS) levels in both species were significantly higher than those of the control (p < 0.05). The site of ROS production and accumulation in K. brevis and S. costatum under nano-TiO{sub 2} exposure was explored with the addition of inhibitors of different electron transfer chains. This study indicated that nano-TiO{sub 2} in algal suspensions inhibited the growth

  8. Effect of atmospheric aging on volatility and reactive oxygen species of biodiesel exhaust nano-particles

    Science.gov (United States)

    Pourkhesalian, A. M.; Stevanovic, S.; Rahman, M. M.; Faghihi, E. M.; Bottle, S. E.; Masri, A. R.; Brown, R. J.; Ristovski, Z. D.

    2015-08-01

    In the prospect of limited energy resources and climate change, effects of alternative biofuels on primary emissions are being extensively studied. Our two recent studies have shown that biodiesel fuel composition has a significant impact on primary particulate matter emissions. It was also shown that particulate matter caused by biodiesels was substantially different from the emissions due to petroleum diesel. Emissions appeared to have higher oxidative potential with the increase in oxygen content and decrease of carbon chain length and unsaturation levels of fuel molecules. Overall, both studies concluded that chemical composition of biodiesel is more important than its physical properties in controlling exhaust particle emissions. This suggests that the atmospheric aging processes, including secondary organic aerosol formation, of emissions from different fuels will be different as well. In this study, measurements were conducted on a modern common-rail diesel engine. To get more information on realistic properties of tested biodiesel particulate matter once they are released into the atmosphere, particulate matter was exposed to atmospheric oxidants, ozone and ultra-violet light; and the change in their properties was monitored for different biodiesel blends. Upon the exposure to oxidative agents, the chemical composition of the exhaust changes. It triggers the cascade of photochemical reactions resulting in the partitioning of semi-volatile compounds between the gas and particulate phase. In most of the cases, aging lead to the increase in volatility and oxidative potential, and the increment of change was mainly dependent on the chemical composition of fuels as the leading cause for the amount and the type of semi-volatile compounds present in the exhaust.

  9. Anticancer effect of (S)-crizotinib on osteosarcoma cells by targeting MTH1 and activating reactive oxygen species.

    Science.gov (United States)

    Qing, Xiangcheng; Shao, Zengwu; Lv, Xiao; Pu, Feifei; Gao, Feng; Liu, Lei; Shi, Deyao

    2018-04-01

    MTH1 has become a new rising star in the field of 'cancer phenotypic lethality' and can be targeted in many kinds of tumors. This study aimed to explore the anticancer effect of MTH1-targeted drug (S)-crizotinib on osteosarcoma (OS) cells. We detected MTH1 expression in OS tissues and cells using immunohistochemistry and western blot. The effects of MTH1 on OS cell viability were explored using the siRNA technique and CCK8. The anticancer effects of the MTH1-targeted drug (S)-crizotinib on OS cells were explored by in-vitro assays. The intracellular 8-oxo-dGTP level and oxygen reactive species (ROS) of OS cells were detected by Cy3-conjugated avidin staining and dichlorofluorescein diacetate staining, respectively. The expression of MTH1 was significantly higher in OS tissues and cell lines than that in the corresponding adjacent tissues and osteoblastic cell line. The proliferation of OS cells was significantly inhibited through knockdown of MTH1 by siRNA technology. (S)-Crizotinib could inhibit the proliferation of OS cells with an increase in the apoptosis levels and causing G0/G1 arrest by targeting MTH1 and activating ROS. In addition, (S)-crizotinib could inhibit the migration of OS cells. (S)-Crizotinib could suppress the proliferation and migration, cause G0/G1 arrest, and increase the apoptosis level of OS cells by targeting MTH1 and activating ROS. This study will provide a promising therapeutic target and the theoretical basis for the clinical application of (S)-crizotinib in OS.

  10. The Fumarate Reductase of Bacteroides thetaiotaomicron, unlike That of Escherichia coli, Is Configured so that It Does Not Generate Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Zheng Lu

    2017-01-01

    Full Text Available The impact of oxidative stress upon organismal fitness is most apparent in the phenomenon of obligate anaerobiosis. The root cause may be multifaceted, but the intracellular generation of reactive oxygen species (ROS likely plays a key role. ROS are formed when redox enzymes accidentally transfer electrons to oxygen rather than to their physiological substrates. In this study, we confirm that the predominant intestinal anaerobe Bacteroides thetaiotaomicron generates intracellular ROS at a very high rate when it is aerated. Fumarate reductase (Frd is a prominent enzyme in the anaerobic metabolism of many bacteria, including B. thetaiotaomicron, and prior studies of Escherichia coli Frd showed that the enzyme is unusually prone to ROS generation. Surprisingly, in this study biochemical analysis demonstrated that the B. thetaiotaomicron Frd does not react with oxygen at all: neither superoxide nor hydrogen peroxide is formed. Subunit-swapping experiments indicated that this difference does not derive from the flavoprotein subunit at which ROS normally arise. Experiments with the related enzyme succinate dehydrogenase discouraged the hypothesis that heme moieties are responsible. Thus, resistance to oxidation may reflect a shift of electron density away from the flavin moiety toward the iron-sulfur clusters. This study shows that the autoxidizability of a redox enzyme can be suppressed by subtle modifications that do not compromise its physiological function. One implication is that selective pressures might enhance the oxygen tolerance of an organism by manipulating the electronic properties of its redox enzymes so they do not generate ROS.

  11. Comparative study of activities in reactive oxygen species production/defense system in mitochondria of rat brain and liver, and their susceptibility to methylmercury toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Mori, N.; Hirayama, K. [Kumamoto University, School of Health Science, Kumamoto (Japan); Yasutake, A. [National Institute for Minamata Disease, Minamata (Japan)

    2007-11-15

    The involvement of oxidative stress has been suggested as a mechanism for neurotoxicity caused by methylmercury (MeHg), but the mechanism for MeHg selective toxicity in the central nervous system is still unclear. In this research, to clarify the mechanism of selective neurotoxicity caused by MeHg, the oxygen consumption levels, the reactive oxygen species (ROS) production rates and several antioxidant levels in mitochondria were compared among the cerebrum, cerebellum and liver of male Wistar rats. In addition, the alterations of these indexes were examined in MeHg-intoxicated rats (oral administration of 10 mg/kg day, for 5 days). Although the cerebrum and cerebellum in intact rats showed higher mitochondrial oxygen consumption levels and ROS production rates than the liver, glutathione peroxidase (GPX) and superoxide dismutase (SOD) activities were much lower in the cerebrum and cerebellum than in the liver. Especially, the cerebellum showed the highest oxygen consumption and ROS production rate and the lowest mitochondrial glutathione (GSH) levels among the tissues examined. In the MeHg-treated rats, decrease in the oxygen consumption and increase in the ROS generation were found only in the cerebellum mitochondria, despite a lower Hg accumulation in the mitochondrial fraction compared to the liver. Since MeHg treatment produced an enhancement of ROS generation in cerebellum mitochondria supplemented with succinate substrates, MeHg-induced oxidative stress might affect the complex II-III mediated pathway in the electron transfer chain in the cerebellum mitochondria. Our study suggested that inborn factors, high production system activity and low defense system activity of ROS in the brain, would relate to the high susceptibility of the central nervous system to MeHg toxicity. (orig.)

  12. Bartonella Species, an Emerging Cause of Blood-Culture-Negative Endocarditis.

    Science.gov (United States)

    Okaro, Udoka; Addisu, Anteneh; Casanas, Beata; Anderson, Burt

    2017-07-01

    Since the reclassification of the genus Bartonella in 1993, the number of species has grown from 1 to 45 currently designated members. Likewise, the association of different Bartonella species with human disease continues to grow, as does the range of clinical presentations associated with these bacteria. Among these, blood-culture-negative endocarditis stands out as a common, often undiagnosed, clinical presentation of infection with several different Bartonella species. The limitations of laboratory tests resulting in this underdiagnosis of Bartonella endocarditis are discussed. The varied clinical picture of Bartonella infection and a review of clinical aspects of endocarditis caused by Bartonella are presented. We also summarize the current knowledge of the molecular basis of Bartonella pathogenesis, focusing on surface adhesins in the two Bartonella species that most commonly cause endocarditis, B. henselae and B. quintana . We discuss evidence that surface adhesins are important factors for autoaggregation and biofilm formation by Bartonella species. Finally, we propose that biofilm formation is a critical step in the formation of vegetative masses during Bartonella -mediated endocarditis and represents a potential reservoir for persistence by these bacteria. Copyright © 2017 American Society for Microbiology.

  13. Deep Nitrate Deficit Observed in the Highly Oxygenated East/Japan Sea and Its Possible Cause

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    Il-Nam Kim

    2012-01-01

    Full Text Available We present evidence of denitrification on the continental slopes of the Ulleung Basin (UB and the Eastern Japan Basin (EJB near the Tatar Strait (TtS in the East/Japan Sea (EJS, despite its high water column dissolved oxygen concentrations. Some nutrient concentration data deviate significantly from the fitted regression line of nitrate (N vs. phosphate (P in deep waters, indicating a loss of nitrate in the region. The EJS has a lower N/P ratio (ca. 12.4 below 300 dbar than a traditional Redfield ratio (16. The N/P ratio and oxygen concentration are substantially lower at several locations whose depths are close to the sediment-water interface, near TtS (500 - 1100 dbar and in UB (1100 - 2200 dbar. The decreased nitrate concentration is smaller than the expected nitrate level (a low N/P ratio of < 12.4, and a secondary nitrite peak near the bottom of these two regions: taken collectively, both indicate the presence of denitrification in the bottom layer. It is speculated that active re-mineralization and denitrification may occur simultaneously along the rich organic matter bottom layer on the slope environment. Denitrification rates are estimated at ~3 - 33 μmol N m-2 d-1. Current estimates do not support the previous idea of basin-wide denitrification in EJS, although the N/P ratio is low like in other hypoxic/anoxic seas. A better understanding of the denitrification process is necessary for predicting future changes of nitrogen cycle in the well-oxygenated EJS considering the decadal-scale physical and biogeochemical changes that have occurred.

  14. Antioxidant enzyme expression and reactive oxygen species damage in prostatic intraepithelial neoplasia and cancer.

    Science.gov (United States)

    Bostwick, D G; Alexander, E E; Singh, R; Shan, A; Qian, J; Santella, R M; Oberley, L W; Yan, T; Zhong, W; Jiang, X; Oberley, T D

    2000-07-01

    Oxidative stress results in damage to cellular structures and has been linked to many diseases, including cancer. The authors sought to determine whether the expression of three major antioxidant enzymes, copper-zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), and catalase, was altered in human prostate carcinoma and its likely precursor, high grade prostatic intraepithelial neoplasia (PIN). The level of reactive oxygen species damage was evaluated by measuring the expression of the DNA adduct 8-hydroxydeoxyguanosine. The authors evaluated the tissue expression of the antioxidant enzymes in prostate carcinoma by immunohistochemistry, immunogold electron microscopy, and enzymatic assay. The polymerase chain reaction was used to amplify and screen tissue specimens for the genes of SOD1, SOD2, and extracellular SOD (SOD3). Matched paraffin embedded tissue sections were evaluated by RNA in situ hybridization for expression of SOD1 and immunohistochemically for the DNA adduct 8-hydroxydeoxyguanosine. All prostatic tissues, including cancer, displayed immunoreactivity for the three antioxidant enzymes in epithelial cells, with no staining of the stroma, inflammatory cells, or endothelial cells. The number of immunoreactive cells was greater in benign epithelium than in PIN and cancer for each enzyme. The mean percentage and intensity of immunoreactive cells was greatest for SOD2, intermediate for SOD1, and lower for catalase. Staining in cancer was heterogeneous. Immunogold ultrasound studies revealed strong mitochondrial labeling for SOD2, which was greater in benign epithelium than in cancer; SOD1 labeling was invariably weaker, with nuclear labeling in benign epithelium and cytoplasmic labeling in cancer cells. There was no difference in enzyme activity for the three antioxidant enzymes between benign epithelium and cancer. No mutations were found in the 5 exons of SOD1, 5 exons of SOD2, and 3 exons of SOD3, except for 3 of 20 cases with

  15. AKTIVITAS REACTIVE OXYGEN SPECIES MAKROFAG AKIBAT STIMULASI GEL LIDAH BUAYA PADA INFEKSI Salmonella typhimurium

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    R. Susanti

    2012-09-01

    Full Text Available Reactive Oxygen Species (ROS merupakan salah satu lethal chemical yang dapatmembunuh dan mengeliminasi bakteri pada sel fagosit. Lidah Buaya (Aloevera banyak dipakai sebagai pengobatan tradisional, tetapi belum ada buktiilmiah sampai tingkat seluler apalagi subseluler dalam hal efek imunostimulanpada penyakit infeksi. Tujuan penelitian ini adalah untuk mengetahui aktivitasimunostimulan dari gel lidah buaya yang ditunjukkan oleh aktivitas ROS makrofagsecara in vivo terhadap infeksi bakteri patogen Salmonella typhimurium. Sebanyak24 ekor mencit BABL/c betina umur 8-10 minggu berat 20-30 gram dikelompokkansecara acak menjadi empat kelompok, masing-masing kelompok enam ekor.Kelompok kontrol tidak diberi gel Aloe vera, sementara kelompok P1, P2, dan P3berturut-turut diberi gel Aloe vera 0,5 ml/ekor/hari; 1,0 ml/ekor/hari, dan 1,5ml/ekor/hari. Pemberian gel Aloe vera dilakukan selama sembilan hari. Pada harike-6, mencit diinfeksi bakteri patogen Salmonella typhimurium intraperitoneal105 CFU. Selanjutnya pada hari ke-10 mencit didislokasi dan dibedah, diambilmakrofag dari peritoneum untuk dianalisis produksi ROS-nya. Hasil penelitianmenunjukkan bahwa pemberian gel Aloe vera berpengaruh signi..ikan terhadappeningkatan produksi ROS makrofag mencit BALB/c yang diinfeksi Salmonellatyphimurium. Terdapat perbedaan secara signi..ikan antara kelompok kontroldengan kelompok P1, P2, dan P3, tetapi tidak terdapat perbedaan signi..ikan antarkelompok P1, P2, dan P3. Pemberian gel Aloe vera dosis 0,5 ml/ekor/hari sudahmampu meningkatkan produksi ROS makrofag. Reactive Oxygen Species (ROS is one of lethal chemicals that can kill and eliminatebacteria in phagocytic cells. Aloe vera is widely used as traditional medicine, but thereis no scienti..ic evidence to prove the effect of immunostimulatory of the Aloe vera gel oninfectious disease in the cellular or subcellular level. This research aims to determinethe immunostimulatory activity of Aloe vera gel showed by

  16. Controlled intracellular generation of reactive oxygen species in human mesenchymal stem cells using porphyrin conjugated nanoparticles

    Science.gov (United States)

    Lavado, Andrea S.; Chauhan, Veeren M.; Alhaj Zen, Amer; Giuntini, Francesca; Jones, D. Rhodri E.; Boyle, Ross W.; Beeby, Andrew; Chan, Weng C.; Aylott, Jonathan W.

    2015-08-01

    Nanoparticles capable of generating controlled amounts of intracellular reactive oxygen species (ROS), that advance the study of oxidative stress and cellular communication, were synthesized by functionalizing polyacrylamide nanoparticles with zinc(ii) porphyrin photosensitisers. Controlled ROS production was demonstrated in human mesenchymal stem cells (hMSCs) through (1) production of nanoparticles functionalized with varying percentages of Zn(ii) porphyrin and (2) modulating the number of doses of excitation light to internalized nanoparticles. hMSCs challenged with nanoparticles functionalized with increasing percentages of Zn(ii) porphyrin and high numbers of irradiations of excitation light were found to generate greater amounts of ROS. A novel dye, which is transformed into fluorescent 7-hydroxy-4-trifluoromethyl-coumarin in the presence of hydrogen peroxide, provided an indirect indicator for cumulative ROS production. The mitochondrial membrane potential was monitored to investigate the destructive effect of increased intracellular ROS production. Flow cytometric analysis of nanoparticle treated hMSCs suggested irradiation with excitation light signalled controlled apoptotic cell death, rather than uncontrolled necrotic cell death. Increased intracellular ROS production did not induce phenotypic changes in hMSC subcultures.Nanoparticles capable of generating controlled amounts of intracellular reactive oxygen species (ROS), that advance the study of oxidative stress and cellular communication, were synthesized by functionalizing polyacrylamide nanoparticles with zinc(ii) porphyrin photosensitisers. Controlled ROS production was demonstrated in human mesenchymal stem cells (hMSCs) through (1) production of nanoparticles functionalized with varying percentages of Zn(ii) porphyrin and (2) modulating the number of doses of excitation light to internalized nanoparticles. hMSCs challenged with nanoparticles functionalized with increasing percentages of Zn

  17. Modulation of adipocyte lipogenesis by octanoate: involvement of reactive oxygen species

    Directory of Open Access Journals (Sweden)

    Han Jianrong

    2006-07-01

    Full Text Available Abstract Background Octanoate is a medium-chain fatty acid (MCFA that is rich in milk and tropical dietary lipids. It also accounts for 70% of the fatty acids in commercial medium chain triglycerides (MCT. Use of MCT for weight control tracks back to early 1950s and is highlighted by recent clinical trials. The molecular mechanisms of the weight reduction effect remain not completely understood. The findings of significant amounts of MCFA in adipose tissue in MCT-fed animals and humans suggest a direct influence of MCFA on fat cell functions. Methods 3T3-L1 adipocytes were treated with octanoate in a high glucose culture medium supplemented with 10% fetal bovine serum and 170 nM insulin. The effects on lipogenesis, fatty acid oxidation, cellular concentration of reactive oxygen species (ROS, and the expression and activity of peroxisome proliferator receptor gamma (PPARγ and its associated lipogenic genes were assessed. In selected experiments, long-chain fatty acid oleate, PPARγ agonist troglitazone, and antioxidant N-acetylcysteine were used in parallel. Effects of insulin, L-carnitine, and etomoxir on β-oxidation were also measured. Results β-oxidation of octanoate was primarily independent of CPT-I. Treatment with octanoate was linked to an increase in ROS in adipocytes, a decrease in triglyceride synthesis, and reduction of lipogenic gene expression. Co-treatment with troglitazone, N-acetylcysteine, or over-expression of glutathione peroxidase largely reversed the effects of octanoate. Conclusion These findings suggest that octanoate-mediated inactivation of PPARγ might contribute to the down regulation of lipogenic genes in adipocytes, and ROS appears to be involved as a mediator in this process.

  18. Impact of hypothalamic reactive oxygen species in the control of energy metabolism and food intake

    Directory of Open Access Journals (Sweden)

    Anne eDrougard

    2015-02-01

    Full Text Available Hypothalamus is a key area involved in the control of metabolism and food intake via the integrations of numerous signals (hormones, neurotransmitters, metabolites from various origins. These factors modify hypothalamic neurons activity and generate adequate molecular and behavioral responses to control energy balance. In this complex integrative system, a new concept has been developed in recent years, that includes reactive oxygen species (ROS as a critical player in energy balance. ROS are known to act in many signaling pathways in different peripheral organs, but also in hypothalamus where they regulate food intake and metabolism by acting on different types of neurons, including proopiomelanocortin (POMC and agouti-related protein (AgRP/neuropeptide Y (NPY neurons. Hypothalamic ROS release is under the influence of different factors such as pancreatic and gut hormones, adipokines (leptin, apelin,..., neurotransmitters and nutrients (glucose, lipids,.... The sources of ROS production are multiple including NADPH oxidase, but also the mitochondria which is considered as the main ROS producer in the brain. ROS are considered as signaling molecules, but conversely impairment of this neuronal signaling ROS pathway contributes to alterations of autonomic nervous system and neuroendocrine function, leading to metabolic diseases such as obesity and type 2 diabetes.In this review we focus our attention on factors that are able to modulate hypothalamic ROS release in order to control food intake and energy metabolism, and whose deregulations could participate to the development of pathological conditions. This novel insight reveals an original mechanism in the hypothalamus that controls energy balance and identify hypothalamic ROS signaling as a potential therapeutic strategy to treat metabolic disorders.

  19. Selenoprotein P Inhibits Radiation-Induced Late Reactive Oxygen Species Accumulation and Normal Cell Injury

    Energy Technology Data Exchange (ETDEWEB)

    Eckers, Jaimee C.; Kalen, Amanda L.; Xiao, Wusheng; Sarsour, Ehab H.; Goswami, Prabhat C., E-mail: prabhat-goswami@uiowa.edu

    2013-11-01

    Purpose: Radiation is a common mode of cancer therapy whose outcome is often limited because of normal tissue toxicity. We have shown previously that the accumulation of radiation-induced late reactive oxygen species (ROS) precedes cell death, suggesting that metabolic oxidative stress could regulate cellular radiation response. The purpose of this study was to investigate whether selenoprotein P (SEPP1), a major supplier of selenium to tissues and an antioxidant, regulates late ROS accumulation and toxicity in irradiated normal human fibroblasts (NHFs). Methods and Materials: Flow cytometry analysis of cell viability, cell cycle phase distribution, and dihydroethidium oxidation, along with clonogenic assays, were used to measure oxidative stress and toxicity. Human antioxidant mechanisms array and quantitative real-time polymerase chain reaction assays were used to measure gene expression during late ROS accumulation in irradiated NHFs. Sodium selenite addition and SEPP1 overexpression were used to determine the causality of SEPP1 regulating late ROS accumulation and toxicity in irradiated NHFs. Results: Irradiated NHFs showed late ROS accumulation (4.5-fold increase from control; P<.05) that occurs after activation of the cell cycle checkpoint pathways and precedes cell death. The mRNA levels of CuZn- and Mn-superoxide dismutase, catalase, peroxiredoxin 3, and thioredoxin reductase 1 increased approximately 2- to 3-fold, whereas mRNA levels of cold shock domain containing E1 and SEPP1 increased more than 6-fold (P<.05). The addition of sodium selenite before the radiation treatment suppressed toxicity (45%; P<.05). SEPP1 overexpression suppressed radiation-induced late ROS accumulation (35%; P<.05) and protected NHFs from radiation-induced toxicity (58%; P<.05). Conclusion: SEPP1 mitigates radiation-induced late ROS accumulation and normal cell injury.

  20. Pivotal Roles of Ginsenoside Rg3 in Tumor Apoptosis Through Regulation of Reactive Oxygen Species.

    Science.gov (United States)

    Sun, Hwa Yeon; Lee, Jun Hee; Han, Yong-Seok; Yoon, Yeo Min; Yun, Chul Won; Kim, Jae Heon; Song, Yun Seob; Lee, Sang Hun

    2016-09-01

    Elevated production of reactive oxygen species (ROS) is observed in various cancer types and pathophysiological conditions. In cancer cells, ROS induce cell proliferation, genetic instability, and a malignant phenotype. Ginsenoside Rg3 is the main pharmacologically active component in ginseng and has been reported to have an antioxidant effect. To overcome lung cancer by regulating the ROS level, we investigated the antitumor effect and mechanism of Rg3 and its antioxidative property on Lewis lung carcinoma (LLC) cells. Inhibition of ROS was suppressed in LLC cells by Rg3 treatment, and these cells were used to investigate the antioxidant, antiproliferative, and antitumor effects in LLC cells. ROS production was increased in cells grown in serum-containing media (conditioned media) compared to those grown in serum-free media. The high level of ROS induced LLC cell proliferation, but treatment with Rg3 (200 ng/ml) resulted in reduction of ROS, leading to inhibition of cell proliferation. Treatment with Rg3 significantly reduced cyclin and cyclin-dependent kinase expression in LLC cells. Additionally, Rg3 treatment significantly suppressed activation of mitogen-activated protein kinases and induced LLC cell apoptosis through activation of pro-apoptotic proteins and suppression of anti-apoptotic proteins. Taken together, these findings demonstrate the role of Rg3 in reduction of the intracellular ROS level, attenuation of proliferation via augmentation of cell cycle- and cell proliferation-associated proteins, and activation of apoptosis through regulation of apoptosis-associated proteins in LLC. These findings suggest that Rg3 could be used as a therapeutic agent in lung cancer. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  1. IGF-I enhances cellular senescence via the reactive oxygen species-p53 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Handayaningsih, Anastasia-Evi; Takahashi, Michiko; Fukuoka, Hidenori; Iguchi, Genzo; Nishizawa, Hitoshi; Yamamoto, Masaaki; Suda, Kentaro [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Takahashi, Yutaka, E-mail: takahash@med.kobe-u.ac.jp [Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Cellular senescence plays an important role in tumorigenesis and aging process. Black-Right-Pointing-Pointer We demonstrated IGF-I enhanced cellular senescence in primary confluent cells. Black-Right-Pointing-Pointer IGF-I enhanced cellular senescence in the ROS and p53-dependent manner. Black-Right-Pointing-Pointer These results may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging. -- Abstract: Cellular senescence is characterized by growth arrest, enlarged and flattened cell morphology, the expression of senescence-associated {beta}-galactosidase (SA-{beta}-gal), and by activation of tumor suppressor networks. Insulin-like growth factor-I (IGF-I) plays a critical role in cellular growth, proliferation, tumorigenesis, and regulation of aging. In the present study, we show that IGF-I enhances cellular senescence in mouse, rat, and human primary cells in the confluent state. IGF-I induced expression of a DNA damage marker, {gamma}H2AX, the increased levels of p53 and p21 proteins, and activated SA-{beta}-gal. In the confluent state, an altered downstream signaling of IGF-I receptor was observed. Treatment with a reactive oxygen species (ROS) scavenger, N-acetylcystein (NAC) significantly suppressed induction of these markers, indicating that ROS are involved in the induction of cellular senescence by IGF-I. In p53-null mouse embryonic fibroblasts, the IGF-I-induced augmentation of SA-{beta}-gal and p21 was inhibited, demonstrating that p53 is required for cellular senescence induced by IGF-I. Thus, these data reveal a novel pathway whereby IGF-I enhances cellular senescence in the ROS and p53-dependent manner and may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging.

  2. A high precision method for quantitative measurements of reactive oxygen species in frozen biopsies.

    Directory of Open Access Journals (Sweden)

    Kirsti Berg

    Full Text Available OBJECTIVE: An electron paramagnetic resonance (EPR technique using the spin probe cyclic hydroxylamine 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CMH was introduced as a versatile method for high precision quantification of reactive oxygen species, including the superoxide radical in frozen biological samples such as cell suspensions, blood or biopsies. MATERIALS AND METHODS: Loss of measurement precision and accuracy due to variations in sample size and shape were minimized by assembling the sample in a well-defined volume. Measurement was carried out at low temperature (150 K using a nitrogen flow Dewar. The signal intensity was measured from the EPR 1st derivative amplitude, and related to a sample, 3-carboxy-proxyl (CP• with known spin concentration. RESULTS: The absolute spin concentration could be quantified with a precision and accuracy better than ±10 µM (k = 1. The spin concentration of samples stored at -80°C could be reproduced after 6 months of storage well within the same error estimate. CONCLUSION: The absolute spin concentration in wet biological samples such as biopsies, water solutions and cell cultures could be quantified with higher precision and accuracy than normally achievable using common techniques such as flat cells, tissue cells and various capillary tubes. In addition; biological samples could be collected and stored for future incubation with spin probe, and also further stored up to at least six months before EPR analysis, without loss of signal intensity. This opens for the possibility to store and transport incubated biological samples with known accuracy of the spin concentration over time.

  3. Reactive oxygen species promote heat shock protein 90-mediated HBV capsid assembly

    International Nuclear Information System (INIS)

    Kim, Yoon Sik; Seo, Hyun Wook; Jung, Guhung

    2015-01-01

    Hepatitis B virus (HBV) infection induces reactive oxygen species (ROS) production and has been associated with the development of hepatocellular carcinoma (HCC). ROS are also an important factor in HCC because the accumulated ROS leads to abnormal cell proliferation and chromosome mutation. In oxidative stress, heat shock protein 90 (Hsp90) and glutathione (GSH) function as part of the defense mechanism. Hsp90 prevents cellular component from oxidative stress, and GSH acts as antioxidants scavenging ROS in the cell. However, it is not known whether molecules regulated by oxidative stress are involved in HBV capsid assembly. Based on the previous study that Hsp90 facilitates HBV capsid assembly, which is an important step for the packing of viral particles, here, we show that ROS enrich Hsp90-driven HBV capsid formation. In cell-free system, HBV capsid assembly was facilitated by ROS with Hsp90, whereas it was decreased without Hsp90. In addition, GSH inhibited the function of Hsp90 to decrease HBV capsid assembly. Consistent with the result of cell-free system, ROS and buthionine sulfoximine (BS), an inhibitor of GSH synthesis, increased HBV capsid formation in HepG2.2.15 cells. Thus, our study uncovers the interplay between ROS and Hsp90 during HBV capsid assembly. - Highlights: • We examined H 2 O 2 and GSH modulate HBV capsid assembly. • H 2 O 2 facilitates HBV capsid assembly in the presence of Hsp90. • GSH inhibits function of Hsp90 in facilitating HBV capsid assembly. • H 2 O 2 and GSH induce conformation change of Hsp90

  4. Reactive oxygen species in unstimulated hemocytes of the pacific oyster Crassostrea gigas: a mitochondrial involvement.

    Directory of Open Access Journals (Sweden)

    Ludovic Donaghy

    Full Text Available 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 (Δψ(m of hemocytes. First, this work confirmed the specificity of JC-10 probe to measure Δψ(m in oyster hemocytes, without being affected by ΔpH, 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 Δψ(m and ΔpH. 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.

  5. Impact of hypothalamic reactive oxygen species in the regulation of energy metabolism and food intake.

    Science.gov (United States)

    Drougard, Anne; Fournel, Audren; Valet, Philippe; Knauf, Claude

    2015-01-01

    Hypothalamus is a key area involved in the control of metabolism and food intake via the integrations of numerous signals (hormones, neurotransmitters, metabolites) from various origins. These factors modify hypothalamic neurons activity and generate adequate molecular and behavioral responses to control energy balance. In this complex integrative system, a new concept has been developed in recent years, that includes reactive oxygen species (ROS) as a critical player in energy balance. ROS are known to act in many signaling pathways in different peripheral organs, but also in hypothalamus where they regulate food intake and metabolism by acting on different types of neurons, including proopiomelanocortin (POMC) and agouti-related protein (AgRP)/neuropeptide Y (NPY) neurons. Hypothalamic ROS release is under the influence of different factors such as pancreatic and gut hormones, adipokines (leptin, apelin,…), neurotransmitters and nutrients (glucose, lipids,…). The sources of ROS production are multiple including NADPH oxidase, but also the mitochondria which is considered as the main ROS producer in the brain. ROS are considered as signaling molecules, but conversely impairment of this neuronal signaling ROS pathway contributes to alterations of autonomic nervous system and neuroendocrine function, leading to metabolic diseases such as obesity and type 2 diabetes. In this review we focus our attention on factors that are able to modulate hypothalamic ROS release in order to control food intake and energy metabolism, and whose deregulations could participate to the development of pathological conditions. This novel insight reveals an original mechanism in the hypothalamus that controls energy balance and identify hypothalamic ROS signaling as a potential therapeutic strategy to treat metabolic disorders.

  6. Live Candida albicans Suppresses Production of Reactive Oxygen Species in Phagocytes▿ †

    Science.gov (United States)

    Wellington, Melanie; Dolan, Kristy; Krysan, Damian J.

    2009-01-01

    Production of reactive oxygen species (ROS) is an important aspect of phagocyte-mediated host responses. Since phagocytes play a crucial role in the host response to Candida albicans, we examined the ability of Candida to modulate phagocyte ROS production. ROS production was measured in the murine macrophage cell line J774 and in primary phagocytes using luminol-enhanced chemiluminescence. J774 cells, murine polymorphonuclear leukocytes (PMN), human monocytes, and human PMN treated with live C. albicans produced significantly less ROS than phagocytes treated with heat-killed C. albicans. Live C. albicans also suppressed ROS production in murine bone marrow-derived macrophages from C57BL/6 mice, but not from BALB/c mice. Live C. albicans also suppressed ROS in response to external stimuli. C. albicans and Candida glabrata suppressed ROS production by phagocytes, whereas Saccharomyces cerevisiae stimulated ROS production. The cell wall is the initial point of contact between Candida and phagocytes, but isolated cell walls from both heat-killed and live C. albicans stimulated ROS production. Heat-killed C. albicans has increased surface exposure of 1,3-β-glucan, a cell wall component that can stimulate phagocytes. To determine whether surface 1,3-β-glucan exposure accounted for the difference in ROS production, live C. albicans cells were treated with a sublethal dose of caspofungin to increase surface 1,3-β-glucan exposure. Caspofungin-treated C. albicans was fully able to suppress ROS production, indicating that suppression of ROS overrides stimulatory signals from 1,3-β-glucan. These studies indicate that live C. albicans actively suppresses ROS production in phagocytes in vitro, which may represent an important immune evasion mechanism. PMID:18981256

  7. Induction of apoptosis by plumbagin through reactive oxygen species-mediated inhibition of topoisomerase II

    International Nuclear Information System (INIS)

    Kawiak, Anna; Piosik, Jacek; Stasilojc, Grzegorz; Gwizdek-Wisniewska, Anna; Marczak, Lukasz; Stobiecki, Maciej; Bigda, Jacek; Lojkowska, Ewa

    2007-01-01

    Reactive oxygen species (ROS) have been recognized as key molecules, which can selectively modify proteins and therefore regulate cellular signalling including apoptosis. Plumbagin, a naphthoquinone exhibiting antitumor activity, is known to generate ROS and has been found to inhibit the activity of topoisomerase II (Topo II) through the stabilization of the Topo II-DNA cleavable complex. The objective of this research was to clarify the role of ROS and Topo II inhibition in the induction of apoptosis mediated by plumbagin. As determined by the comet assay, plumbagin induced DNA cleavage in HL-60 cells, whereas in a cell line with reduced Topo II activity-HL-60/MX2, the level of DNA damage was significantly decreased. The onset of DNA strand break formation in HL-60 cells was delayed in comparison with the generation of intracellular ROS. In HL-60/MX2 cells, ROS were generated at a similar rate, whereas a significant reduction in the level of DNA damage was detected. The pretreatment of cells with N-acetylcysteine (NAC) attenuated plumbagin-induced DNA damage, pointing out to the involvement of ROS generation in cleavable complex formation. These results suggest that plumbagin-induced ROS does not directly damage DNA but requires the involvement of Topo II. Furthermore, experiments carried out using light spectroscopy indicated no direct interactions between plumbagin and DNA. The induction of apoptosis was significantly delayed in HL-60/MX2 cells indicating the involvement of Topo II inhibition in plumbagin-mediated apoptosis. Thus, these findings strongly suggest ROS-mediated inhibition of Topo II as an important mechanism contributing to the apoptosis-inducing properties of plumbagin

  8. Low Po2 conditions induce reactive oxygen species formation during contractions in single skeletal muscle fibers

    Science.gov (United States)

    Shiah, Amy; Roberts, William J.; Chien, Michael T.; Wagner, Peter D.; Hogan, Michael C.

    2013-01-01

    Contractions in whole skeletal muscle during hypoxia are known to generate reactive oxygen species (ROS); however, identification of real-time ROS formation within isolated single skeletal muscle fibers has been challenging. Consequently, there is no convincing evidence showing increased ROS production in intact contracting fibers under low Po2 conditions. Therefore, we hypothesized that intracellular ROS generation in single contracting skeletal myofibers increases during low Po2 compared with a value approximating normal resting Po2. Dihydrofluorescein was loaded into single frog (Xenopus) fibers, and fluorescence was used to monitor ROS using confocal microscopy. Myofibers were exposed to two maximal tetanic contractile periods (1 contraction/3 s for 2 min, separated by a 60-min rest period), each consisting of one of the following treatments: high Po2 (30 Torr), low Po2 (3–5 Torr), high Po2 with ebselen (antioxidant), or low Po2 with ebselen. Ebselen (10 μM) was administered before the designated contractile period. ROS formation during low Po2 treatment was greater than during high Po2 treatment, and ebselen decreased ROS generation in both low- and high-Po2 conditions (P Po2. Force was reduced >30% for each condition except low Po2 with ebselen, which only decreased ∼15%. We concluded that single myofibers under low Po2 conditions develop accelerated and more oxidative stress than at Po2 = 30 Torr (normal human resting Po2). Ebselen decreases ROS formation in both low and high Po2, but only mitigates skeletal muscle fatigue during reduced Po2 conditions. PMID:23576612

  9. Effect of magnesium on reactive oxygen species production in the thigh muscles of broiler chickens.

    Science.gov (United States)

    Liu, Y X; Guo, Y M; Wang, Z

    2007-02-01

    1. The objective of the present study was to investigate the effect of magnesium (Mg) on reactive oxygen species (ROS) production in the thigh muscles of broiler chickens. A total of 96 1-d-old male Arbor Acre broiler chickens were randomly allocated into two groups, fed either on low-Mg or control diets containing about 1.2 g/kg or 2.4 g Mg/kg dry matter. 2. The low-Mg diet significantly increased malondialdehyde (MDA) concentration and decreased glutathione (GSH) in the thigh muscles of broiler chickens. ROS production in the thigh muscle homogenate was significantly higher in the low-Mg group than in the control group. Compared with the control, muscle Mg concentration of broiler chickens from the low-Mg group decreased by 9.5%. 3. Complex II and III activities of the mitochondrial electron transport chain in broilers on low-Mg diet increased by 23 and 35%, respectively. Significant negative correlations between ROS production and the activities of mitochondrial electron transport chain (ETC) complexes were observed. 4. The low-Mg diet did not influence contents of iron (Fe) or calcium (Ca) in the thigh muscles of broiler chickens and did not influence unsaturated fatty acid composition (except C18:2) in the thigh muscles. 5. A low-Mg diet decreased Mg concentration in the thigh muscles of broiler chickens and then induced higher activities of mitochondrial ETC, consequently increasing ROS production. These results suggest that Mg modulates the oxidation-anti-oxidation system of the thigh muscles at least partly through affecting ROS production.

  10. Green synthesized silver nanoparticles destroy multidrug resistant bacteria via reactive oxygen species mediated membrane damage

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    Balaram Das

    2017-09-01

    Full Text Available The growing need of antimicrobial agent for novel therapies against multi-drug resistant bacteria has drawn researchers to green nanotechnology. Especially, eco-friendly biosynthesis of silver nanoparticles (Ag NPs has shown its interesting impact against bacterial infection in laboratory research. In this study, a simple method was developed to form Ag NPs at room temperature, bio-reduction of silver ions from silver nitrate salt by leaf extract from Ocimum gratissimum. The Ag NPs appear to be capped with plant proteins, but are otherwise highly crystalline and pure. The Ag NPs have a zeta potential of −15 mV, a hydrodynamic diameter of 31 nm with polydispersity index of 0.65, and dry sizes of 18 ± 3 nm and 16 ± 2 nm, based on scanning and transmission electron microscopy respectively. The minimum inhibitory concentration (MIC of the Ag NPs against a multi-drug resistant Escherichia coli was 4 μg/mL and the minimum bactericidal concentration (MBC was 8 μg/mL, while the MIC and MBC against a resistant strain of Staphylococcus aureus were slightly higher at 8 μg/mL and 16 μg/mL respectively. Further, the Ag NPs inhibited biofilm formation by both Escherichia coli and S. aureus at concentrations similar to the MIC for each strain. Treatment of E. coli and S. aureus with Ag NPs resulted in damage to the surface of the cells and the production of reactive oxygen species. Both mechanisms likely contribute to bacterial cell death. In summary, this new method appears promising for green biosynthesis of pure Ag NPs with potent antimicrobial activity.

  11. Reactive oxygen species promote heat shock protein 90-mediated HBV capsid assembly

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    Kim, Yoon Sik, E-mail: yumshak@naver.com; Seo, Hyun Wook, E-mail: suruk@naver.com; Jung, Guhung, E-mail: drjung@snu.ac.kr

    2015-02-13

    Hepatitis B virus (HBV) infection induces reactive oxygen species (ROS) production and has been associated with the development of hepatocellular carcinoma (HCC). ROS are also an important factor in HCC because the accumulated ROS leads to abnormal cell proliferation and chromosome mutation. In oxidative stress, heat shock protein 90 (Hsp90) and glutathione (GSH) function as part of the defense mechanism. Hsp90 prevents cellular component from oxidative stress, and GSH acts as antioxidants scavenging ROS in the cell. However, it is not known whether molecules regulated by oxidative stress are involved in HBV capsid assembly. Based on the previous study that Hsp90 facilitates HBV capsid assembly, which is an important step for the packing of viral particles, here, we show that ROS enrich Hsp90-driven HBV capsid formation. In cell-free system, HBV capsid assembly was facilitated by ROS with Hsp90, whereas it was decreased without Hsp90. In addition, GSH inhibited the function of Hsp90 to decrease HBV capsid assembly. Consistent with the result of cell-free system, ROS and buthionine sulfoximine (BS), an inhibitor of GSH synthesis, increased HBV capsid formation in HepG2.2.15 cells. Thus, our study uncovers the interplay between ROS and Hsp90 during HBV capsid assembly. - Highlights: • We examined H{sub 2}O{sub 2} and GSH modulate HBV capsid assembly. • H{sub 2}O{sub 2} facilitates HBV capsid assembly in the presence of Hsp90. • GSH inhibits function of Hsp90 in facilitating HBV capsid assembly. • H{sub 2}O{sub 2} and GSH induce conformation change of Hsp90.

  12. Curcumin-induced inhibition of cellular reactive oxygen species generation: novel therapeutic implications.

    Science.gov (United States)

    Balasubramanyam, M; Koteswari, A Adaikala; Kumar, R Sampath; Monickaraj, S Finny; Maheswari, J Uma; Mohan, V

    2003-12-01

    There is evidence for increased levels of circulating reactive oxygen species (ROS) in diabetics, as indirectly inferred by the findings of increased lipid peroxidation and decreased antioxidant status. Direct measurements of intracellular generation of ROS using fluorescent dyes also demonstrate an association of oxidative stress with diabetes. Although phenolic compounds attenuate oxidative stress-related tissue damage, there are concerns over toxicity of synthetic phenolic antioxidants and this has considerably stimulated interest in investigating the role of natural phenolics in medicinal applications. Curcumin (the primary active principle in turmeric, Curcuma longa Linn.) has been claimed to represent a potential antioxidant and antiinflammatory agent with phytonutrient and bioprotective properties. However there are lack of molecular studies to demonstrate its cellular action and potential molecular targets. In this study the antioxidant effect of curcumin as a function of changes in cellular ROS generation was tested. Our results clearly demonstrate that curcumin abolished both phorbol-12 myristate-13 acetate (PMA) and thapsigargin-induced ROS generation in cells from control and diabetic subjects. The pattern of these ROS inhibitory effects as a function of dose-dependency suggests that curcumin mechanistically interferes with protein kinase C (PKC) and calcium regulation. Simultaneous measurements of ROS and Ca2+ influx suggest that a rise in cytosolic Ca2+ may be a trigger for increased ROS generation. We suggest that the antioxidant and antiangeogenic actions of curcumin, as a mechanism of inhibition of Ca2+ entry and PKC activity, should be further exploited to develop suitable and novel drugs for the treatment of diabetic retinopathy and other diabetic complications.

  13. Sites of reactive oxygen species generation by mitochondria oxidizing different substrates

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    Casey L. Quinlan

    2013-01-01

    Full Text Available Mitochondrial radical production is important in redox signaling, aging and disease, but the relative contributions of different production sites are poorly understood. We analyzed the rates of superoxide/H2O2 production from different defined sites in rat skeletal muscle mitochondria oxidizing a variety of conventional substrates in the absence of added inhibitors: succinate; glycerol 3-phosphate; palmitoylcarnitine plus carnitine; or glutamate plus malate. In all cases, the sum of the estimated rates accounted fully for the measured overall rates. There were two striking results. First, the overall rates differed by an order of magnitude between substrates. Second, the relative contribution of each site was very different with different substrates. During succinate oxidation, most of the superoxide production was from the site of quinone reduction in complex I (site IQ, with small contributions from the flavin site in complex I (site IF and the quinol oxidation site in complex III (site IIIQo. However, with glutamate plus malate as substrate, site IQ made little or no contribution, and production was shared between site IF, site IIIQo and 2-oxoglutarate dehydrogenase. With palmitoylcarnitine as substrate, the flavin site in complex II (site IIF was a major contributor (together with sites IF and IIIQo, and with glycerol 3-phosphate as substrate, five different sites all contributed, including glycerol 3-phosphate dehydrogenase. Thus, the relative and absolute contributions of specific sites to the production of reactive oxygen species in isolated mitochondria depend very strongly on the substrates being oxidized, and the same is likely true in cells and in vivo.

  14. Salicylic Acid Alleviates Aluminum Toxicity in Soybean Roots through Modulation of Reactive Oxygen Species Metabolism

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    Ning Liu

    2017-11-01

    Full Text Available As an important signal molecule, salicylic acid (SA improves plant tolerance to aluminum (Al stress. The objective of this study was to investigate the effects of exogenous SA application on the dynamics of endogenous SA and reactive oxygen species in soybean (Glycine max L. exposed to Al stress. The roots of soybean seedlings were exposed to a combination of AlCl3 (30 μM and SA (10 μM/PAC (100 μM, paclobutrazol, SA biosynthesis inhibitor for 3, 6, 9, and 12 h. Al stress induced an increase in endogenous SA concentration in a time-dependent manner, also verified by the up-regulated expression of GmNPR1, an SA-responsive gene. Al stress increased the activities of phenylalanine ammonia-lyase (PAL and benzoic acid 2-hydroxylase (BA2H, and the contents of SA, O2- and malondialdehyde (MDA in the root apex. The application of exogenous SA increased PAL and BA2H, and reduced O2- and MDA contents in soybean roots under Al stress. PAC inhibited the SA induced increase in BA2H activity. In addition, the SA application resulted in a rapid increase in hydrogen peroxide (H2O2 concentration under Al stress, followed by a sharp decrease. Compared with the plants exposed to Al alone, Al+SA plants possessed higher activities of superoxide dismutase, peroxidase, and ascorbate peroxidase, and lower catalase activity, indicating that SA alleviated Al-induced oxidative damage. These results suggested that PAL and BA2H were involved in Al-induced SA production and showed that SA alleviated the adverse effects of Al toxicity by modulating the cellular H2O2 level and the antioxidant enzyme activities in the soybean root apex.

  15. Vascular smooth muscle modulates endothelial control of vasoreactivity via reactive oxygen species production through myoendothelial communications.

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    Marie Billaud

    Full Text Available BACKGROUND: Endothelial control of vascular smooth muscle plays a major role in the resulting vasoreactivity implicated in physiological or pathological circulatory processes. However, a comprehensive understanding of endothelial (EC/smooth muscle cells (SMC crosstalk is far from complete. Here, we have examined the role of gap junctions and reactive oxygen species (ROS in this crosstalk and we demonstrate an active contribution of SMC to endothelial control of vasomotor tone. METHODOLOGY/PRINCIPAL FINDINGS: In small intrapulmonary arteries, quantitative RT-PCR, Western Blot analyses and immunofluorescent labeling evidenced connexin (Cx 37, 40 and 43 in EC and/or SMC. Functional experiments showed that the Cx-mimetic peptide targeted against Cx 37 and Cx 43 ((37,43Gap27 (1 reduced contractile and calcium responses to serotonin (5-HT simultaneously recorded in pulmonary arteries and (2 abolished the diffusion in SMC of carboxyfluorescein-AM loaded in EC. Similarly, contractile and calcium responses to 5-HT were decreased by superoxide dismutase and catalase which, catabolise superoxide anion and H(2O(2, respectively. Both Cx- and ROS-mediated effects on the responses to 5-HT were reversed by L-NAME, a NO synthase inhibitor or endothelium removal. Electronic paramagnetic resonance directly demonstrated that 5-HT-induced superoxide anion production originated from the SMC. Finally, whereas 5-HT increased NO production, it also decreased cyclic GMP content in isolated intact arteries. CONCLUSIONS/SIGNIFICANCE: These data demonstrate that agonist-induced ROS production in SMC targeting EC via myoendothelial gap junctions reduces endothelial NO-dependent control of pulmonary vasoreactivity. Such SMC modulation of endothelial control may represent a signaling pathway controlling vasoreactivity under not only physiological but also pathological conditions that often implicate excessive ROS production.

  16. Reactive oxygen species are crucial for hydroxychavicol toxicity toward KB epithelial cells.

    Science.gov (United States)

    Jeng, J H; Wang, Y J; Chang, W H; Wu, H L; Li, C H; Uang, B J; Kang, J J; Lee, J J; Hahn, L J; Lin, B R; Chang, M C

    2004-01-01

    Betel quid (BQ) chewing shows a strong correlation to the incidence of oral submucous fibrosis (OSF), leukoplakia and oral cancer. BQ contains mainly areca nut, lime, Piper betle leaf (PBL) and the inflorescence of P. betle (IPB). Hydroxychavicol (4-allyl-catechol, HC), as a major phenolic compound in PBL and IPB, is shown to induce oxidative stress, glutathione (GSH) depletion and cell cycle deregulation. Using bivariate BrdU/PI flow cytometry, KB cells in DNA synthesis (S phase) are shown to be sensitive to the toxic effect of HC and show cell cycle arrest and apoptosis following exposure to 0.1 and 0.3 mM HC. HC-induced apoptosis and cell cycle arrest are associated with mitochondrial membrane potential (delta Psim) depolarization as revealed by a decrease in rhodamine fluorescence. N-acetyl-L-cysteine (1 mM), superoxide dismutase (100 U/ml) and catalase (1000 U/ml) were effective in prevention of HC-induced GSH depletion (as indicated by chloromethylfluorescein fluorescence), reactive oxygen species (ROS) production (by dichlorofluorescein fluorescence), cell cycle arrest and apoptosis. However, dimethylthiourea (2 mM), neocuproine (1 mM), 1,10-phenanthroline (200 microM) and desferrioxamine (0.5 mM) showed little effect on HC-induced cell changes. HC elevated the cellular and mitochondrial GSH levels at moderate concentrations (0.05-0.1 mM), whereas at a concentration of 0.3 mM, inhibitory effects were noted. These results indicate that HC consumption may be associated with BQ-chewing-related oral mucosal diseases via GSH depletion, ROS production, mitochondrial dysfunction, cell cycle disturbance and the induction of apoptosis. These events are related to the production of superoxide radicals and hydrogen peroxide.

  17. Global inhibition of reactive oxygen species (ROS inhibits paclitaxel-induced painful peripheral neuropathy.

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    Mehmet Fidanboylu

    Full Text Available Paclitaxel (Taxol® is a widely used chemotherapeutic agent that has a major dose limiting side-effect of painful peripheral neuropathy. Currently there is no effective therapy for the prevention or treatment of chemotherapy-induced painful peripheral neuropathies. Evidence for mitochondrial dysfunction during paclitaxel-induced pain was previously indicated with the presence of swollen and vacuolated neuronal mitochondria. As mitochondria are a major source of reactive oxygen species (ROS, the aim of this study was to examine whether pharmacological inhibition of ROS could reverse established paclitaxel-induced pain or prevent the development of paclitaxel-induced pain. Using a rat model of paclitaxel-induced pain (intraperitoneal 2 mg/kg paclitaxel on days 0, 2, 4 & 6, the effects of a non-specific ROS scavenger, N-tert-Butyl-α-phenylnitrone (PBN and a superoxide selective scavenger, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL were compared. Systemic 100 mg/kg PBN administration markedly inhibited established paclitaxel-induced mechanical hypersensitivity to von Frey 8 g and 15 g stimulation and cold hypersensitivity to plantar acetone application. Daily systemic administration of 50 mg/kg PBN (days -1 to 13 completely prevented mechanical hypersensitivity to von Frey 4 g and 8 g stimulation and significantly attenuated mechanical hypersensitivity to von Frey 15 g. Systemic 100 mg/kg TEMPOL had no effect on established paclitaxel-induced mechanical or cold hypersensitivity. High dose (250 mg/kg systemic TEMPOL significantly inhibited mechanical hypersensitivity to von Frey 8 g & 15 g, but to a lesser extent than PBN. Daily systemic administration of 100 mg/kg TEMPOL (day -1 to 12 did not affect the development of paclitaxel-induced mechanical hypersensitivity. These data suggest that ROS play a causal role in the development and maintenance of paclitaxel-induced pain, but such effects cannot be attributed to superoxide radicals

  18. Fanconi anemia links reactive oxygen species to insulin resistance and obesity.

    Science.gov (United States)

    Li, Jie; Sipple, Jared; Maynard, Suzette; Mehta, Parinda A; Rose, Susan R; Davies, Stella M; Pang, Qishen

    2012-10-15

    Insulin resistance is a hallmark of obesity and type 2 diabetes. Reactive oxygen species (ROS) have been proposed to play a causal role in insulin resistance. However, evidence linking ROS to insulin resistance in disease settings has been scant. Since both oxidative stress and diabetes have been observed in patients with the Fanconi anemia (FA), we sought to investigate the link between ROS and insulin resistance in this unique disease model. Mice deficient for the Fanconi anemia complementation group A (Fanca) or Fanconi anemia complementation group C (Fancc) gene seem to be diabetes-prone, as manifested by significant hyperglycemia and hyperinsulinemia, and rapid weight gain when fed with a high-fat diet. These phenotypic features of insulin resistance are characterized by two critical events in insulin signaling: a reduction in tyrosine phosphorylation of the insulin receptor (IR) and an increase in inhibitory serine phosphorylation of the IR substrate-1 in the liver, muscle, and fat tissues from the insulin-challenged FA mice. High levels of ROS, spontaneously accumulated or generated by tumor necrosis factor alpha in these insulin-sensitive tissues of FA mice, were shown to underlie the FA insulin resistance. Treatment of FA mice with the natural anti-oxidant Quercetin restores IR signaling and ameliorates the diabetes- and obesity-prone phenotypes. Finally, pairwise screen identifies protein-tyrosine phosphatase (PTP)-α and stress kinase double-stranded RNA-dependent protein kinase (PKR) that mediate the ROS effect on FA insulin resistance. These findings establish a pathogenic and mechanistic link between ROS and insulin resistance in a unique human disease setting. ROS accumulation contributes to the insulin resistance in FA deficiency by targeting both PTP-α and PKR.

  19. Testosterone improves erectile function through inhibition of reactive oxygen species generation in castrated rats

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    Rui Li

    2016-05-01

    Full Text Available Testosterone is overwhelmingly important in regulating erectile physiology. However, the associated molecular mechanisms are poorly understood. The purpose of this study was to explore the effects and mechanisms of testosterone in erectile dysfunction (ED in castrated rats. Forty male Sprague-Dawley rats were randomized to four groups (control, sham-operated, castration and castration-with-testosterone-replacement. Reactive oxygen species (ROS production was measured by dihydroethidium (DHE staining. Erectile function was assessed by the recording of intracavernous pressure (ICP and mean arterial blood pressure (MAP. Protein expression levels were examined by western blotting. We found that castration reduced erectile function and that testosterone restored it. Nitric oxide synthase (NOS activity was decrease in the castrated rats, and testosterone administration attenuated this decrease (each p < 0.05. The testosterone, dihydrotestosterone, cyclic guanosine monophosphate (cGMP and cyclic adenosine monophosphate (cAMP concentrations were lower in the castrated rats, and testosterone restored these levels (each p < 0.05. Furthermore, the cyclooxygenase-2 (COX-2 and prostacyclin synthase (PTGIS expression levels and phospho-endothelial nitric oxide synthase (p-eNOS, Ser1177/endothelial nitric oxide synthase (eNOS ratio were reduced in the castrated rats compared with the controls (each p < 0.05. In addition, the p40phox and p67phox expression levels were increased in the castrated rats, and testosterone reversed these changes (each p < 0.05. Overall, our results demonstrate that testosterone ameliorates ED after castration by reducing ROS production and increasing the activity of the eNOS/cGMP and COX-2/PTGIS/cAMP signaling pathways.

  20. Salicylic acid alleviates aluminum toxicity in soybean roots through modulation of reactive oxygen species metabolism

    Science.gov (United States)

    Liu, Ning; Song, Fengbin; Zhu, Xiancan; You, Jiangfeng; Yang, Zhenming; Li, Xiangnan

    2017-11-01

    As an important signal molecule, salicylic acid (SA) improves plant tolerance to aluminum (Al) stress. The objective of this study was to investigate the effects of exogenous SA application on the dynamics of endogenous SA and reactive oxygen species in soybean (Glycine max L.) exposed to Al stress. The roots of soybean seedlings were exposed to a combination of AlCl3 (30 μM) and SA (10 μM)/PAC (100 μM, paclobutrazol, SA biosynthesis inhibitor) for 3, 6, 9 and 12 h. Al stress induced an increase in endogenous SA concentration in a time-dependent manner, also verified by the up-regulated expression of GmNPR1, an SA-responsive gene. Al stress increased the activities of phenylalanine ammonia-lyase (PAL) and benzoic acid 2-hydroxylase (BA2H), and the contents of SA, O2- and malondialdehyde (MDA) in the root apex. The application of exogenous SA increased PAL and BA2H, and reduced O2- and MDA contents in soybean roots under Al stress. PAC inhibited the SA induced increase in BA2H activity. In addition, the SA application resulted in a rapid increase in hydrogen peroxide (H2O2) concentration under Al stress, followed by a sharp decrease. Compared with the plants exposed to Al alone, Al+SA plants possessed higher activities of superoxide dismutase, peroxidase and ascorbate peroxidase, and lower catalase activity, indicating that SA alleviated Al-induced oxidative damage. These results suggested that PAL and BA2H were involved in Al-induced SA production and showed that SA alleviated the adverse effects of Al toxicity by modulating the cellular H2O2 level and the antioxidant enzyme activities in the soybean root apex.

  1. Fetal programming alters reactive oxygen species production in sheep cardiac mitochondria.

    Science.gov (United States)

    von Bergen, Nicholas H; Koppenhafer, Stacia L; Spitz, Douglas R; Volk, Kenneth A; Patel, Sonali S; Roghair, Robert D; Lamb, Fred S; Segar, Jeffrey L; Scholz, Thomas D

    2009-04-01

    Exposure to an adverse intrauterine environment is recognized as an important risk factor for the development of cardiovascular disease later in life. Although oxidative stress has been proposed as a mechanism for the fetal programming phenotype, the role of mitochondrial O(2)(*-) (superoxide radical) production has not been explored. To determine whether mitochondrial ROS (reactive oxygen species) production is altered by in utero programming, pregnant ewes were given a 48-h dexamethasone (dexamethasone-exposed, 0.28 mg.kg(-1) of body weight.day(-1)) or saline (control) infusion at 27-28 days gestation (term=145 days). Intact left ventricular mitochondria and freeze-thaw mitochondrial membranes were studied from offspring at 4-months of age. AmplexRed was used to measure H(2)O(2) production. Activities of the antioxidant enzymes Mn-SOD (manganese superoxide dismutase), GPx (glutathione peroxidase) and catalase were measured. Compared with controls, a significant increase in Complex I H(2)O(2) production was found in intact mitochondria from dexamethasone-exposed animals. The treatment differences in Complex I-driven H(2)O(2) production were not seen in mitochondrial membranes. Consistent changes in H(2)O(2) production from Complex III in programmed animals were not found. Despite the increase in H(2)O(2) production in intact mitochondria from programmed animals, dexamethasone exposure significantly increased mitochondrial catalase activity, whereas Mn-SOD and GPx activities were unchanged. The results of the present study point to an increase in the rate of release of H(2)O(2) from programmed mitochondria despite an increase in catalase activity. Greater mitochondrial H(2)O(2) release into the cell may play a role in the development of adult disease following exposure to an adverse intrauterine environment.

  2. Scoparone attenuates RANKL-induced osteoclastic differentiation through controlling reactive oxygen species production and scavenging

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Hyun; Jang, Hae-Dong, E-mail: haedong@hnu.kr

    2015-02-15

    Scoparone, one of the bioactive components of Artemisia capillaris Thunb, has various biological properties including immunosuppressive, hepatoprotective, anti-allergic, anti-inflammatory, and antioxidant effects. This study aims at evaluating the anti-osteoporotic effect of scoparone and its underlying mechanism in vitro. Scoparone demonstrated potent cellular antioxidant capacity. It was also found that scoparone inhibited the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation and suppressed cathepsin K and tartrate-resistant acid phosphatase (TRAP) expression via c-jun N-terminal kinase (JNK)/extracellular signal-regulated kinase (ERK)/p38-mediated c-Fos–nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) signaling pathway. During osteoclast differentiation, the production of general reactive oxygen species (ROS) and superoxide anions was dose-dependently attenuated by scoparone. In addition, scoparone diminished NADPH (nicotinamide adenine dinucleotide phosphate) oxidase 1 (Nox1) expression and activation via the tumor necrosis factor receptor-associated factor 6 (TRAF6)–cSrc–phosphatidylinositol 3-kinase (PI3k) signaling pathway and prevented the disruption of mitochondrial electron transport chain system. Furthermore, scoparone augmented the expression of superoxide dismutase 1 (SOD1) and catalase (CAT). The overall results indicate that the inhibitory effect of scoparone on RANKL-induced osteoclast differentiation is attributed to the suppressive effect on ROS and superoxide anion production by inhibiting Nox1 expression and activation and protecting the mitochondrial electron transport chain system and the scavenging effect of ROS resulting from elevated SOD1 and CAT expression. - Highlights: • Scoparone dose-dependently inhibited RANKL-induced osteoclast differentiation. • Scoparone diminished general ROS and superoxide anions in a dose-dependent manner. • Scoparone inhibited Nox1 expression and

  3. Mining the enzymes involved in the detoxification of reactive oxygen species (ROS) in sugarcane.

    Science.gov (United States)

    Kurama, Eiko E; Fenille, Roseli C; Rosa, Vicente E; Rosa, Daniel D; Ulian, Eugenio C

    2002-07-01

    Summary Adopting the sequencing of expressed sequence tags (ESTs) of a sugarcane database derived from libraries induced and not induced by pathogens, we identified EST clusters homologous to genes corresponding to enzymes involved in the detoxification of reactive oxygen species. The predicted amino acids of these enzymes are superoxide dismutases (SODs), glutathione-S-transferase (GST), glutathione peroxidase (GPX), and catalases. Three MnSOD mitochondrial precursors and 10 CuZnSOD were identified in sugarcane: the MnSOD mitochondrial precursor is 96% similar to the maize MnSOD mitochondrial precursor and, of the 10 CuZnSOD identified, seven were 98% identical to maize cytosolic CuZnSOD4 and one was 67% identical to putative peroxisomal CuZnSOD from Arabidopsis. Three homologues to class Phi GST were 87-88% identical to GST III from maize. Five GPX homologues were identified: three were homologous to cytosolic GPX from barley, one was 88% identical to phospholipid hydroperoxide glutathione peroxidase (PHGPX) from rice, and the last was 71% identical to GPX from A. thaliana. Three enzymes similar to maize catalase were identified in sugarcane: two were similar to catalase isozyme 3 and catalase chain 3 from maize, which are mitochondrial, and one was similar to catalase isozyme 1 from maize, whose location is peroxisomal subcellular. All enzymes were induced in all sugarcane libraries (flower, seed, root, callus, leaves) and also in the pathogen-induced libraries, except for CuZnSOD whose cDNA was detected in none of the libraries induced by pathogens (Acetobacter diazotroficans and Herbaspirillum rubrisubalbicans). The expression of the enzymes SOD, GST, GPX, and catalases involved in the detoxification was examined using reverse transcriptase-polymerase chain reaction in cDNA from leaves of sugarcane under biotic stress conditions, inoculated with Puccinia melanocephala, the causal agent of sugarcane rust disease.

  4. Reactive Oxygen Species and Their Implications on CD4+ T Cells in Type 1 Diabetes.

    Science.gov (United States)

    Previte, Dana M; Piganelli, Jon D

    2017-11-28

    Previous work has indicated that type 1 diabetes (T1D) pathology is highly driven by reactive oxygen species (ROS). One way in which ROS shape the autoimmune response demonstrated in T1D is by promoting CD4 + T cell activation and differentiation. As CD4 + T cells are a significant contributor to pancreatic β cell destruction in T1D, understanding how ROS impact their development, activation, and differentiation is critical. Recent Advances: CD4 + T cells themselves generate ROS via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase expression and electron transport chain activity. Moreover, T cells can also be exposed to exogenous ROS generated by other immune cells (e.g., macrophages and dendritic cells) and β cells. Genetically modified animals and ROS inhibitors have demonstrated that ROS blockade during activation results in CD4 + T cell hyporesponsiveness and reduced diabetes incidence. Critical Issues and Future Directions: Although the majority of studies with regard to T1D and CD4 + T cells have been done to examine the influence of redox on CD4 + T cell activation, this is not the only circumstance in which a T cell can be impacted by redox. ROS and redox have also been shown to play roles in CD4 + T cell-related tolerogenic mechanisms, including thymic selection and regulatory T cell-mediated suppression. However, the effect of these mechanisms with respect to T1D pathogenesis remains elusive. Therefore, pursuing these avenues may provide valuable insight into the global role of ROS and redox in autoreactive CD4 + T cell formation and function. Antioxid. Redox Signal. 00, 000-000.

  5. Role of reactive oxygen species in the radiation response of human hematopoietic stem/progenitor cells.

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    Masaru Yamaguchi

    Full Text Available Hematopoietic stem/progenitor cells (HSPCs, which are present in small numbers in hematopoietic tissues, can differentiate into all hematopoietic lineages and self-renew to maintain their undifferentiated phenotype. HSPCs are extremely sensitive to oxidative stressors such as anti-cancer agents, radiation, and the extensive accumulation of reactive oxygen species (ROS. The quiescence and stemness of HSPCs are maintained by the regulation of mitochondrial biogenesis, ROS, and energy homeostasis in a special microenvironment called the stem cell niche. The present study evaluated the relationship between the production of intracellular ROS and mitochondrial function during the proliferation and differentiation of X-irradiated CD34(+ cells prepared from human placental/umbilical cord blood HSPCs. Highly purified CD34(+ HSPCs exposed to X-rays were cultured in liquid and semi-solid medium supplemented with hematopoietic cytokines. X-irradiated CD34(+ HSPCs treated with hematopoietic cytokines, which promote their proliferation and differentiation, exhibited dramatically suppressed cell growth and clonogenic potential. The amount of intracellular ROS in X-irradiated CD34(+ HSPCs was significantly higher than that in non-irradiated cells during the culture period. However, neither the intracellular mitochondrial content nor the mitochondrial superoxide production was elevated in X-irradiated CD34(+ HSPCs compared with non-irradiated cells. Radiation-induced gamma-H2AX expression was observed immediately following exposure to 4 Gy of X-rays and gradually decreased during the culture period. This study reveals that X-irradiation can increase persistent intracellular ROS in human CD34(+ HSPCs, which may not result from mitochondrial ROS due to mitochondrial dysfunction, and indicates that substantial DNA double-strand breakage can critically reduce the stem cell function.

  6. Reactive Oxygen Species and Mitochondrial Homeostasis as Regulators of Stem Cell Fate and Function.

    Science.gov (United States)

    Tan, Darren Q; Suda, Toshio

    2018-07-10

    The precise role and impact of reactive oxygen species (ROS) in stem cells, which are essential for lifelong tissue homeostasis and regeneration, remain of significant interest to the field. The long-term regenerative potential of a stem cell compartment is determined by the delicate balance between quiescence, self-renewal, and differentiation, all of which can be influenced by ROS levels. Recent Advances: The past decade has seen a growing appreciation for the importance of ROS and redox homeostasis in various stem cell compartments, particularly those of hematopoietic, neural, and muscle tissues. In recent years, the importance of proteostasis and mitochondria in relation to stem cell biology and redox homeostasis has garnered considerable interest. Here, we explore the reciprocal relationship between ROS and stem cells, with significant emphasis on mitochondria as a core component of redox homeostasis. We discuss how redox signaling, involving cell-fate determining protein kinases and transcription factors, can control stem cell function and fate. We also address the impact of oxidative stress on stem cells, especially oxidative damage of lipids, proteins, and nucleic acids. We further discuss ROS management in stem cells, and present recent evidence supporting the importance of mitochondrial activity and its modulation (via mitochondrial clearance, biogenesis, dynamics, and distribution [i.e., segregation and transfer]) in stem cell redox homeostasis. Therefore, elucidating the intricate links between mitochondria, cellular metabolism, and redox homeostasis is envisioned to be critical for our understanding of ROS in stem cell biology and its therapeutic relevance in regenerative medicine. Antioxid. Redox Signal. 00, 000-000.

  7. Genomic evidence of reactive oxygen species elevation in papillary thyroid carcinoma with Hashimoto thyroiditis.

    Science.gov (United States)

    Yi, Jin Wook; Park, Ji Yeon; Sung, Ji-Youn; Kwak, Sang Hyuk; Yu, Jihan; Chang, Ji Hyun; Kim, Jo-Heon; Ha, Sang Yun; Paik, Eun Kyung; Lee, Woo Seung; Kim, Su-Jin; Lee, Kyu Eun; Kim, Ju Han

    2015-01-01

    Elevated levels of reactive oxygen species (ROS) have been proposed as a risk factor for the development of papillary thyroid carcinoma (PTC) in patients with Hashimoto thyroiditis (HT). However, it has yet to be proven that the total levels of ROS are sufficiently increased to contribute to carcinogenesis. We hypothesized that if the ROS levels were increased in HT, ROS-related genes would also be differently expressed in PTC with HT. To find differentially expressed genes (DEGs) we analyzed data from the Cancer Genomic Atlas, gene expression data from RNA sequencing: 33 from normal thyroid tissue, 232 from PTC without HT, and 60 from PTC with HT. We prepared 402 ROS-related genes from three gene sets by genomic database searching. We also analyzed a public microarray data to validate our results. Thirty-three ROS related genes were up-regulated in PTC with HT, whereas there were only nine genes in PTC without HT (Chi-square p-value < 0.001). Mean log2 fold changes of up-regulated genes was 0.562 in HT group and 0.252 in PTC without HT group (t-test p-value = 0.001). In microarray data analysis, 12 of 32 ROS-related genes showed the same differential expression pattern with statistical significance. In gene ontology analysis, up-regulated ROS-related genes were related with ROS metabolism and apoptosis. Immune function-related and carcinogenesis-related gene sets were enriched only in HT group in Gene Set Enrichment Analysis. Our results suggested that ROS levels may be increased in PTC with HT. Increased levels of ROS may contribute to PTC development in patients with HT.

  8. Sibutramine provokes apoptosis of aortic endothelial cells through altered production of reactive oxygen and nitrogen species

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, Yoshifumi [Forensic Science Laboratory, Gifu Prefectural Police Headquarters, Gifu 500-8501 (Japan); Shibata, Akinobu; Okumura, Naoko; Ikari, Akira [Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu 501-1196 (Japan); Sasajima, Yasuhide; Suenami, Koichi; Sato, Kiyohito; Takekoshi, Yuji [Forensic Science Laboratory, Gifu Prefectural Police Headquarters, Gifu 500-8501 (Japan); El-Kabbani, Ossama [Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Matsunaga, Toshiyuki, E-mail: matsunagat@gifu-pu.ac.jp [Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu 501-1196 (Japan)

    2017-01-01

    Overdose administration of sibutramine, a serotonin-noradrenalin reuptake inhibitor, is considered to elicit severe side effects including hypertension, whose pathogenic mechanism remains unclear. Here, we found that 48-h incubation with > 10 μM sibutramine provokes apoptosis of human aortic endothelial (HAE) cells. Treatment with the lethal concentration of sibutramine facilitated production of reactive oxygen species (ROS), altered expression of endoplasmic reticulum stress response genes (heat shock protein 70 and C/EBP homologous protein), and inactivated 26S proteasome-based proteolysis. The treatment also decreased cellular level of nitric oxide (NO) through lowering of expression and activity of endothelial NO synthase. These results suggest that ROS production and depletion of NO are crucial events in the apoptotic mechanism and may be linked to the pathogenesis of vasoconstriction elicited by the drug. Compared to sibutramine, its metabolites (N-desmethylsibutramine and N-didesmethylsibutramine) were much less cytotoxic to HAE cells, which hardly metabolized sibutramine. In contrast, both the drug and metabolites showed low cytotoxicity to hepatic HepG2 cells with high metabolic potency and expression of cytochrome P450 (CYP) 3A4. The cytotoxicity of sibutramine to HepG2 and Chang Liver cells was remarkably augmented by inhibition and knockdown of CYP3A4. This study also suggests an inverse relationship between sibutramine cytotoxicity and CYP3A4-mediated metabolism into the N-desmethyl metabolites. - Highlights: • Treatment with sibutramine, an anorexiant, induces endothelial cell apoptosis. • The apoptotic mechanism includes induction of ROS and NO depletion. • There is an inverse relationship between sibutramine cytotoxicity and its metabolism.

  9. Light-Emitting Photon-Upconversion Nanoparticles in the Generation of Transdermal Reactive-Oxygen Species.

    Science.gov (United States)

    Prieto, Martin; Rwei, Alina Y; Alejo, Teresa; Wei, Tuo; Lopez-Franco, Maria Teresa; Mendoza, Gracia; Sebastian, Victor; Kohane, Daniel S; Arruebo, Manuel

    2017-12-06

    Common photosensitizers used in photodynamic therapy do not penetrate the skin effectively. In addition, the visible blue and red lights used to excite such photosensitizers have shallow penetration depths through tissue. To overcome these limitations, we have synthesized ultraviolet- and visible-light-emitting, energy-transfer-based upconversion nanoparticles and coencapsulated them inside PLGA-PEG (methoxy poly(ethylene glycol)-b-poly(lactic-co-glycolic acid)) nanoparticles with the photosensitizer protoporphyrin IX. Nd 3+ has been introduced as a sensitizer in the upconversion nanostructure to allow its excitation at 808 nm. The subcytotoxic doses of the hybrid nanoparticles have been evaluated on different cell lines (i.e., fibroblasts, HaCaT, THP-1 monocytic cell line, U251MG (glioblastoma cell line), and mMSCs (murine mesenchymal stem cells). Upon NIR (near infrared)-light excitation, the upconversion nanoparticles emitted UV and VIS light, which consequently activated the generation of reactive-oxygen species (ROS). In addition, after irradiating at 808 nm, the resulting hybrid nanoparticles containing both upconversion nanoparticles and protoporphyrin IX generated 3.4 times more ROS than PLGA-PEG nanoparticles containing just the same dose of protoporphyrin IX. Their photodynamic effect was also assayed on different cell cultures, demonstrating their efficacy in selectively killing treated and irradiated cells. Compared to the topical application of the free photosensitizer, enhanced skin permeation and penetration were observed for the nanoparticulate formulation, using an ex vivo human-skin-permeation experiment. Whereas free protoporphyrin IX remained located at the outer layer of the skin, nanoparticle-encapsulated protoporphyrin IX was able to penetrate through the epidermal layer slightly into the dermis.

  10. The tripeptide feG regulates the production of intracellular reactive oxygen species by neutrophils

    Directory of Open Access Journals (Sweden)

    Davison Joseph S

    2006-06-01

    Full Text Available Abstract Background The D-isomeric form of the tripeptide FEG (feG is a potent anti-inflammatory agent that suppresses type I hypersensitivity (IgE-mediated allergic reactions in several animal species. One of feG's primary actions is to inhibit leukocyte activation resulting in loss of their adhesive and migratory properties. Since activation of neutrophils is often associated with an increase in respiratory burst with the generation of reactive oxygen species (ROS, we examined the effect of feG on the respiratory burst in neutrophils of antigen-sensitized rats. A role for protein kinase C (PKC in the actions of feG was evaluated by using selective isoform inhibitors for PKC. Results At 18h after antigen (ovalbumin challenge of sensitized Sprague-Dawley rats a pronounced neutrophilia occurred; a response that was reduced in animals treated with feG (100 μg/kg. With antigen-challenged animals the protein kinase C (PKC activator, PMA, significantly increased intracellular ROS of circulating neutrophils, as determined by flow cytometry using the fluorescent probe dihydrorhodamine-123. This increase was prevented by treatment with feG at the time of antigen challenge. The inhibitor of PKCδ, rottlerin, which effectively prevented intracellular ROS production by circulating neutrophils of animals receiving a naïve antigen, failed to inhibit PMA-stimulated ROS production if the animals were challenged with antigen. feG treatment, however, re-established the inhibitory effects of the PKCδ inhibitor on intracellular ROS production. The extracellular release of superoxide anion, evaluated by measuring the oxidative reduction of cytochrome C, was neither modified by antigen challenge nor feG treatment. However, hispidin, an inhibitor of PKCβ, inhibited the release of superoxide anion from circulating leukocytes in all groups of animals. feG prevented the increased expression of the β1-integrin CD49d on the circulating neutrophils elicited by antigen

  11. Radiation-Driven Formation of Reactive Oxygen Species in Oxychlorine-Containing Mars Surface Analogues

    Science.gov (United States)

    Georgiou, Christos D.; Zisimopoulos, Dimitrios; Kalaitzopoulou, Electra; Quinn, Richard C.

    2017-04-01

    The present study demonstrates that γ-radiolyzed perchlorate-containing Mars soil salt analogues (in a CO2 atmosphere) generate upon H2O wetting the reactive oxygen species (ROS) superoxide radical (O2•-), hydrogen peroxide (H2O2), and hydroxyl radicals (•OH). This study also validates that analogue radiolysis forms oxychlorine species that, in turn, can UV-photolyze to •OH upon UV photolysis. This investigation was made possible by the development of a new assay for inorganic-origin O2•- and H2O2 determination and by the modification of a previous assay for soil •OH. Results show that radiolyzed Mg(ClO4)2 generates H2O2 and •OH; and when included as part of a mixture analogous to the salt composition of samples analyzed at the Mars Phoenix site, the analogue generated O2•-, H2O2, and •OH, with •OH levels 150-fold higher than in the radiolyzed Mg(ClO4)2 samples. Radiolyzed Mars Phoenix site salt analogue that did not contain Mg(ClO4)2 generated only •OH also at 150-fold higher concentration than Mg(ClO4)2 alone. Additionally, UV photolysis of the perchlorate γ radiolysis product chlorite (ClO2-) generated the oxychlorine products trihalide (Cl3-), chlorine dioxide (ClO2•), and hypochlorite (ClO-), with the formation of •OH by UV photolysis of ClO-. While the generation of ROS may have contributed in part to 14CO2 production in the Viking Labeled Release (LR) experiment and O2 (g) release in the Viking Gas Exchange (GEx) experiment, our results indicate that they are not likely to be the major contributor to the LR and GEx results. However, due to their highly reactive nature, they are expected to play a significant role in the alteration of organics on Mars. Additionally, experiments with hypochlorite show that the thermal stability of NaClO is in the range of the thermal stability observed for thermally liable oxidant responsible for the Viking LR results.

  12. Macrobenthic zonation caused by the oxygen minimum zone on the shelf and slope off central Chile

    Science.gov (United States)

    Gallardo, V. A.; Palma, M.; Carrasco, F. D.; Gutiérrez, D.; Levin, L. A.; Cañete, J. I.

    2004-10-01

    The relationship between macrobenthic (⩾300 μm) zonation and the oxygen minimum zone (OMZ: O 2Chile. Four study sites were sampled during March-April 1999 for abiotic factors, macrofaunal density, biomass, mean individual size, and diversity. Within the OMZ (122-206 m), the macrofaunal density was high (16,478-21,381 individuals m -2) and 69-89% of the organisms were soft-bodied. Density was highest (21,381 individuals m -2), biomass lowest (16.95 g wet weight m -2), and individual size smallest (0.07 mg C individuals -1) at the shelf break site (206 m). Polychaete worms made up 71% of the total abundance, crustaceans 16%, and mollusks only 2%. Total abundance beneath the OMZ (mid-slope site, ˜840 m) was 49% crustaceans and 43% polychaetes. Although existing literature originally led to the hypothesis that both diversity and biomass within the OMZ would be lower than beneath the OMZ, in the present study this was only true for diversity. Biomass distribution, on the other hand, was concave along the depth gradient; the highest values were near the upper edge of (122 m) and beneath (840 m) the OMZ. Indices of the macrofaunal community structure varied in relation to bottom-water oxygen concentration, chlorophyll- a, phaeopigments, and sulfide concentration, but not in relation to grain size, C, N, mud, porosity, redox potential, a bottom-water temperature.

  13. Production of reactive oxygen species from abraded silicates. Implications for the reactivity of the Martian soil

    Science.gov (United States)

    Bak, Ebbe N.; Zafirov, Kaloyan; Merrison, Jonathan P.; Jensen, Svend J. Knak; Nørnberg, Per; Gunnlaugsson, Haraldur P.; Finster, Kai

    2017-09-01

    The results of the Labeled Release and the Gas Exchange experiments conducted on Mars by the Viking Landers show that compounds in the Martian soil can cause oxidation of organics and a release of oxygen in the presence of water. Several sources have been proposed for the oxidizing compounds, but none has been validated in situ and the cause of the observed oxidation has not been resolved. In this study, laboratory simulations of saltation were conducted to examine if and under which conditions wind abrasion of silicates, a process that is common on the Martian surface, can give rise to oxidants in the form of hydrogen peroxide (H2O2) and hydroxyl radicals (ṡOH). We found that silicate samples abraded in simulated Martian atmospheres gave rise to a significant production of H2O2 and ṡOH upon contact with water. Our experiments demonstrated that abraded silicates could lead to a production of H2O2 facilitated by atmospheric O2 and inhibited by carbon dioxide. Furthermore, during simulated saltation the silicate particles became triboelectrically charged and at pressures similar to the Martian surface pressure we observed glow discharges. Electrical discharges can cause dissociation of CO2 and through subsequent reactions lead to a production of H2O2. These results indicate that the reactions linked to electrical discharges are the dominant source of H2O2 during saltation of silicates in a simulated Martian atmosphere, given the low pressure and the relatively high concentration of CO2. Our experiments provide evidence that wind driven abrasion could enhance the reactivity of the Martian soil and thereby could have contributed to the oxidation of organic compounds and the O2 release observed in the Labeled Release and the Gas Exchange experiments. Furthermore, the release of H2O2 and ṡOH from abraded silicates could have a negative effect on the persistence of organic compounds in the Martian soil and the habitability of the Martian surface.

  14. The role of positive selection in determining the molecular cause of species differences in disease

    Directory of Open Access Journals (Sweden)

    Foord Steven M

    2008-10-01

    between species is an important way to gain insight into their molecular causes and may provide a method to predict when animal models do not mirror human biology.

  15. Clinical manifestations of bacteremia caused by Aeromonas species in southern Taiwan.

    Directory of Open Access Journals (Sweden)

    Hung-Jen Tang

    Full Text Available This study is conducted to investigate the clinical characteristics of patients with bacteremia caused by Aeromonas species.Patients with bacteremia caused by Aeromonas species during the period 2009 to 2013 were identified from a computerized database of a regional hospital in southern Taiwan. The medical records of these patients were retrospectively reviewed.A total of 91 patients with bacteremia due to Aeromonas species were identified. In addition to 16 (17.6% primary bacteremia, the most common source of secondary infection is peritonitis (n = 27, 29.7%, followed by biliary tract infection (n = 18, 19.8%, and SSTI (n = 12, 13.2%, pneumonia (n = 9, 9.9%, catheter-related bloodstream infection (n =  5, 5.5%, and genitourinary tract infection (n = 4, 4.4%. A. hydrophila (n = 35, 38.5% was the most common pathogen, followed by A. veronii biovar sobria (n = 31, 34.1%, A. caviae (n = 14, 15.4%, and A. veronii biovar veronii (n = 9, 9.9%. Forty-three (47.3% patients were classified as healthcare-associated infections (HCAI causes by Aeromonas species, and patients with HCAI were more likely to have cancer, and receive immunosuppressant than patients with community-acquired bacteremia. The overall outcomes, including rate of ICU admission, acute respiratory failure, and mortality were 33.3%, 28.6%, and 23.1%, respectively. Multivariate analysis showed that the in-hospital day mortality was significantly associated only with underlying cancer (P <.001, and initial shock (P <.001.Aeromonas species should be considered one of the causative pathogens of healthcare-associated bacteremia, especially in immunocompromised patients. In addition, it can be associated with high fatality. Cancer and initial shock were the poor prognostic factors.

  16. Identification of colletotrichum species causing anthracnose on tahiti lime, tree tomato and mango

    OpenAIRE

    Martínez, Erika P.; Hío, Juan C.; Osorio1, Jairo A.; Torres, María F.

    2009-01-01

    In Colombia, citrus, tree tomato and mango crops are likely to suffer considerable losses from anthracnose caused by several Colletotrichum species, which were identified by the present study on infected organs of the three fruit crops, sampled in different regions of the country. Identification was based on their morphological and molecular characteristics, as well as on fungicide (benomyl and copper hydroxide) sensitivity and pathogenicity tests. The latter assessed infectivity on both the ...

  17. First Molecular Characterization of Leishmania Species Causing Visceral Leishmaniasis among Children in Yemen.

    Science.gov (United States)

    Mahdy, Mohammed A K; Al-Mekhlafi, Abdulsalam M; Abdul-Ghani, Rashad; Saif-Ali, Reyadh; Al-Mekhlafi, Hesham M; Al-Eryani, Samira M; Lim, Yvonne A L; Mahmud, Rohela

    2016-01-01

    Visceral leishmaniasis (VL) is a debilitating, often fatal disease caused by Leishmania donovani complex; however, it is a neglected tropical disease. L. donovani complex comprises two closely related species, L. donovani that is mostly anthroponotic and L. infantum that is zoonotic. Differentiation between these two species is critical due to the differences in their epidemiology and pathology. However, they cannot be differentiated morphologically, and their speciation using isoenzyme-based methods poses a difficult task and may be unreliable. Molecular characterization is now the most reliable method to differentiate between them and to determine their phylogenetic relationships. The present study aims to characterize Leishmania species isolated from bone marrows of Yemeni pediatric patients using sequence analysis of the ribosomal internal transcribed spacer-1 (ITS1) gene. Out of 41 isolates from Giemsa-stained bone marrow smears, 25 isolates were successfully amplified by nested polymerase chain reaction and sequenced in both directions. Phylogenetic analysis using neighbor joining method placed all study isolates in one cluster with L. donovani complex (99% bootstrap). The analysis of ITS1 for microsatellite repeat numbers identified L. infantum in 11 isolates and L. donovani in 14 isolates. These data suggest the possibility of both anthroponotic and zoonotic transmission of VL-causing Leishmania species in Yemen. Exploring the possible animal reservoir hosts is therefore needed for effective control to be achieved.

  18. Pyogranulomatous Pneumonia in Goats Caused by an Undescribed Porphyromonas Species, “Porphyromonas katsikii”

    Science.gov (United States)

    Filioussis, George; Petridou, Evanthia; Karavanis, Emmanouel

    2014-01-01

    A yet-undescribed bacterial species, tentatively named “Porphyromonas katsikii,” was isolated from individuals of a small goat herd with pyogranulomatous pneumonia during an outbreak of acute respiratory disease. The isolated bacteria grew in the form of black-pigmented colonies after 14 days of incubation under anaerobic conditions at 37°C on a tryptic soy blood agar medium. The bacteria were identified as a yet-undescribed Porphyromonas species by determination of the nucleotide sequence of the rrs 16S rRNA gene, and this species was tentatively named Porphyromonas katsikii. PCR amplification with specific primers for this yet-undescribed species revealed the presence of P. katsikii in the lung tissue of all affected animals, while no PCR signals were evidenced from the lungs of healthy goats or from goats with pasteurellosis caused by Mannheimia haemolytica. These data indicate P. katsikii as the causative agent of acute respiratory distress. P. katsikii is phylogenetically related to Porphyromonas somerae and Porphyromonas levii, which cause pathologies in humans and animals, respectively. P. katsikii was not detected by PCR from samples of the gingival pockets or of the faces of healthy goats. PMID:25540395

  19. Pyogranulomatous pneumonia in goats caused by an undescribed Porphyromonas species, "Porphyromonas katsikii".

    Science.gov (United States)

    Filioussis, George; Petridou, Evanthia; Karavanis, Emmanouel; Frey, Joachim

    2015-03-01

    A yet-undescribed bacterial species, tentatively named "Porphyromonas katsikii," was isolated from individuals of a small goat herd with pyogranulomatous pneumonia during an outbreak of acute respiratory disease. The isolated bacteria grew in the form of black-pigmented colonies after 14 days of incubation under anaerobic conditions at 37°C on a tryptic soy blood agar medium. The bacteria were identified as a yet-undescribed Porphyromonas species by determination of the nucleotide sequence of the rrs 16S rRNA gene, and this species was tentatively named Porphyromonas katsikii. PCR amplification with specific primers for this yet-undescribed species revealed the presence of P. katsikii in the lung tissue of all affected animals, while no PCR signals were evidenced from the lungs of healthy goats or from goats with pasteurellosis caused by Mannheimia haemolytica. These data indicate P. katsikii as the causative agent of acute respiratory distress. P. katsikii is phylogenetically related to Porphyromonas somerae and Porphyromonas levii, which cause pathologies in humans and animals, respectively. P. katsikii was not detected by PCR from samples of the gingival pockets or of the faces of healthy goats. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. Differential Activation of Human Keratinocytes by Leishmania Species Causing Localized or Disseminated Disease.

    Science.gov (United States)

    Scorza, Breanna M; Wacker, Mark A; Messingham, Kelly; Kim, Peter; Klingelhutz, Aloysius; Fairley, Janet; Wilson, Mary E

    2017-10-01

    All Leishmania species parasites are introduced into mammalian skin through a sand fly bite, but different species cause distinct clinical outcomes. Mouse studies suggest that early responses are critical determinants of subsequent adaptive immunity in leishmaniasis, yet few studies address the role of keratinocytes, the most abundant cell in the epidermis. We hypothesized that Leishmania infection causes keratinocytes to produce immunomodulatory factors that influence the outcome of infection. Incubation of primary or immortalized human keratinocytes with Leishmania infantum or Leishmania major, which cause visceral or cutaneous leishmaniasis, respectively, elicited dramatically different responses. Keratinocytes incubated with L. infantum significantly increased expression of proinflammatory genes for IL-6, IL-8, tumor necrosis factor, and IL-1B, whereas keratinocytes exposed to several L. major isolates did not. Furthermore, keratinocyte-monocyte co-incubation studies across a 4 µM semipermeable membrane suggested that L. infantum-exposed keratinocytes release soluble factors that enhance monocyte control of intracellular L. infantum replication (P Leishmania species that may affect the course of disease. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Projections of climate-driven changes in tuna vertical habitat based on species-specific differences in blood oxygen affinity.

    Science.gov (United States)

    Mislan, K A S; Deutsch, Curtis A; Brill, Richard W; Dunne, John P; Sarmiento, Jorge L

    2017-10-01

    Oxygen concentrations are hypothesized to decrease in many areas of the ocean as a result of anthropogenically driven climate change, resulting in habitat compression for pelagic animals. The oxygen partial pressure, pO 2 , at which blood is 50% saturated (P 50 ) is a measure of blood oxygen affinity and a gauge of the tolerance of animals for low ambient oxygen. Tuna species display a wide range of blood oxygen affinities (i.e., P 50 values) and therefore may be differentially impacted by habitat compression as they make extensive vertical movements to forage on subdaily time scales. To project the effects of end-of-the-century climate change on tuna habitat, we calculate tuna P 50 depths (i.e., the vertical position in the water column at which ambient pO 2 is equal to species-specific blood P 50 values) from 21st century Earth System Model (ESM) projections included in the fifth phase of the Climate Model Intercomparison Project (CMIP5). Overall, we project P 50 depths to shoal, indicating likely habitat compression for tuna species due to climate change. Tunas that will be most impacted by shoaling are Pacific and southern bluefin tunas-habitat compression is projected for the entire geographic range of Pacific bluefin tuna and for the spawning region of southern bluefin tuna. Vertical shifts in P 50 depths will potentially influence resource partitioning among Pacific bluefin, bigeye, yellowfin, and skipjack tunas in the northern subtropical and eastern tropical Pacific Ocean, the Arabian Sea, and the Bay of Bengal. By establishing linkages between tuna physiology and environmental conditions, we provide a mechanistic basis to project the effects of anthropogenic climate change on tuna habitats. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  2. Induction of Tca8113 tumor cell apoptosis by icotinib is associated with reactive oxygen species mediated p38-MAPK activation.

    Science.gov (United States)

    Yang, Cailing; Yan, Jianguo; Yuan, Guoyan; Zhang, Yinghua; Lu, Derong; Ren, Mingxin; Cui, Weigang

    2014-08-01

    Icotinib, a selective EGFR tyrosine kinase inhibitor (EGFR-TKI), has been shown to exhibit anti-tumor activity against several tumor cell lines. However, the exact molecular mechanism of icotinib's anti-tumor effect remains unknown. This study aims to examine the zytotoxic effect of icotinib on Tca8113 cells and its potential molecular mechanism. Icotinib significantly resulted in dose-dependent cell death as determined by MTT assay, accompanied by increased levels of Bax and DNA fragmentation. Icotinib could also induce Reactive Oxygen Species (ROS) generation. Further studies confirmed that scavenging of reactive oxygen species by N-acetyl-L-cysteine (NAC), and pharmacological inhibition of MAPK reversed icotinib-induced apoptosis in Tca8113 cells. Our data provide evidence that icotinib induces apoptosis, possibly via ROS-mediated MAPK pathway in Tca8113 cells.

  3. Intra-species diversity and epidemiology varies among coagulase-negative Staphylococcus species causing bovine intramammary infections.

    Science.gov (United States)

    Piessens, V; De Vliegher, S; Verbist, B; Braem, G; Van Nuffel, A; De Vuyst, L; Heyndrickx, M; Van Coillie, E

    2012-02-24

    Although many studies report coagulase-negative staphylococci (CNS) as the predominant cause of subclinical bovine mastitis, their epidemiology is poorly understood. In the current study, the genetic diversity within four CNS species frequently associated with bovine intramammary infections, Staphylococcus haemolyticus, S. simulans, S. chromogenes, and S. epidermidis, was determined. For epidemiological purposes, CNS genotypes recovered from bovine milk collected on six Flemish dairy farms were compared with those from the farm environment, and their distribution within the farms was investigated. Genetic diversity was assessed by two molecular typing techniques, amplification fragment length polymorphism (AFLP) and random amplification of polymorphic DNA (RAPD) analysis. Subtyping revealed the highest genetic heterogeneity among S. haemolyticus isolates. A large variety of genotypes was found among environmental isolates, of which several could be linked with intramammary infection, indicating that the environment could act as a potential source for infection. For S. simulans, various genotypes were found in the environment, but a link with IMI was less obvious. For S. epidermidis and S. chromogenes, genetic heterogeneity was limited and the sporadic isolates from environment displayed largely the same genotypes as those from milk. The higher clonality of the S. epidermidis and S. chromogenes isolates from milk suggests that specific genotypes probably disseminate within herds and are more udder-adapted. Environmental sources and cow-to-cow transmission both seem to be involved in the epidemiology of CNS, although their relative importance might substantially vary between species. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Large herbivores maintain termite-caused differences in herbaceous species diversity patterns.

    Science.gov (United States)

    Okullo, Paul; Moe, Stein R

    2012-09-01

    Termites and large herbivores affect African savanna plant communities. Both functional groups are also important for nutrient redistribution across the landscape. We conducted an experiment to study how termites and large herbivores, alone and in combination, affect herbaceous species diversity patterns in an African savanna. Herbaceous vegetation on large vegetated Macrotermes mounds (with and without large herbivores) and on adjacent savanna areas (with and without large herbivores) was monitored over three years in Lake Mburo National Park, Uganda. We found substantial differences in species richness, alpha diversity, evenness, and stability between termite mound herbaceous vegetation and adjacent savanna vegetation. Within months of fencing, levels of species richness, evenness, and stability were no longer significantly different between savanna and mounds. However, fencing reduced the cumulative number of species, particularly for forbs, of which 48% of the species were lost. Fencing increased the beta diversity (dissimilarity among plots) on the resource-poor (in terms of both nutrients and soil moisture) savanna areas, while it did not significantly affect beta diversity on the resource-rich termite mounds. While termites cause substantial heterogeneity in savanna vegetation, large herbivores further amplify these differences by reducing beta diversity on the savanna areas. Large herbivores are, however, responsible for the maintenance of a large number of forbs at the landscape level. These findings suggest that the mechanisms underlying the effects of termites and large herbivores on savanna plant communities scale up to shape community structure and dynamics at a landscape level.

  5. Reactive oxygen species play no role in the candidacidal activity of the salivary antimicrobial peptide histatin 5

    OpenAIRE

    Veerman, Enno C. I.; Nazmi, Kamran; van '​t HOF, Wim; Bolscher, Jan G. M.; den Hertog, Alice L.; Nieuw Amerongen, Arie V.

    2004-01-01

    The mechanism of action of antimicrobial peptides is still a matter of debate. The formation of ROS (reactive oxygen species) has been suggested to be the crucial step in the fungicidal mechanism of a number of antimicrobial peptides, including histatin 5 and lactoferrin-derived peptides. In the present study we have investigated the effects of histatin 5 and of a more amphipathic synthetic derivative, dhvar4, on the generation of ROS in the yeast Candida albicans, using dihydroethidium as an...

  6. Production of Reactive Oxygen Species by Multipotent Stromal Cells/Mesenchymal Stem Cells Upon Exposure to Fas Ligand

    OpenAIRE

    Rodrigues, Melanie; Turner, Omari; Stolz, Donna; Griffith, Linda G.; Wells, Alan

    2011-01-01

    Multipotent stromal cells (MSCs) can be differentiated into osteoblasts and chondrocytes, making these cells candidates to regenerate cranio-facial injuries and lesions in long bones. A major problem with cell replacement therapy, however, is the loss of transplanted MSCs at the site of graft. Reactive oxygen species (ROS) and nonspecific inflammation generated at the ischemic site have been hypothesized to lead to MSCs loss; studies in vitro show MSCs dying both in the presence of ROS or cyt...

  7. Role of reactive oxygen species and Bcl-2 family proteins in TNF-α-induced apoptosis of lymphocytes.

    Science.gov (United States)

    Ryazanceva, N V; Novickiy, V V; Zhukova, O B; Biktasova, A K; Chechina, O E; Sazonova, E V; Belkina, M V; Chasovskih, N Yu; Khaitova, Z K

    2010-08-01

    We studied the in vitro apoptosis-inducing effect of recombinant TNF-α (rTNF-α) on blood lymphocytes from healthy donors. rTNF-α-induced apoptosis was accompanied by an increase in the number of cells with low mitochondrial transmembrane potential, increased intracellular content of reactive oxygen species, reduced content of Bcl-2, Bcl-xL, and Bax proteins, and elevated Bad content. The molecular mechanisms of these changes are discussed.

  8. Oxidative damage of U937 human leukemic cells caused by hydroxyl radical results in singlet oxygen formation.

    Directory of Open Access Journals (Sweden)

    Marek Rác

    Full Text Available The exposure of human cells to oxidative stress leads to the oxidation of biomolecules such as lipids, proteins and nuclei acids. In this study, the oxidation of lipids, proteins and DNA was studied after the addition of hydrogen peroxide and Fenton reagent to cell suspension containing human leukemic monocyte lymphoma cell line U937. EPR spin-trapping data showed that the addition of hydrogen peroxide to the cell suspension formed hydroxyl radical via Fenton reaction mediated by endogenous metals. The malondialdehyde HPLC analysis showed no lipid peroxidation after the addition of hydrogen peroxide, whereas the Fenton reagent caused significant lipid peroxidation. The formation of protein carbonyls monitored by dot blot immunoassay and the DNA fragmentation measured by comet assay occurred after the addition of both hydrogen peroxide and Fenton reagent. Oxidative damage of biomolecules leads to the formation of singlet oxygen as conformed by EPR spin-trapping spectroscopy and the green fluorescence of singlet oxygen sensor green detected by confocal laser scanning microscopy. It is proposed here that singlet oxygen is formed by the decomposition of high-energy intermediates such as dioxetane or tetroxide formed by oxidative damage of biomolecules.

  9. Role of reactive oxygen species in arsenic-induced transformation of human lung bronchial epithelial (BEAS-2B) cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhuo, E-mail: zhuo.zhang@uky.edu [Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536 (United States); Pratheeshkumar, Poyil; Budhraja, Amit; Son, Young-Ok [Center for Research on Environmental Diseases, University of Kentucky, Lexington, KY 40536 (United States); Kim, Donghern [Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536 (United States); Shi, Xianglin [Center for Research on Environmental Diseases, University of Kentucky, Lexington, KY 40536 (United States)

    2015-01-09

    Highlights: • Short term exposure of cells to arsenic causes ROS generation. • Chronical exposure of cells to arsenic causes malignant cell transformation. • Inhibition of ROS generation reduces cell transformation by arsenic. • Arsenic-transformed cells exhibit reduced capacity of generating ROS. • Arsenic-transformed cells exhibit increased levels of antioxidants. - Abstract: Arsenic is an environmental carcinogen, its mechanisms of carcinogenesis remain to be investigated. Reactive oxygen species (ROS) are considered to be important. A previous study (Carpenter et al., 2011) has measured ROS level in human lung bronchial epithelial (BEAS-2B) cells and arsenic-transformed BEAS-2B cells and found that ROS levels were higher in transformed cells than that in parent normal cells. Based on these observations, the authors concluded that cell transformation induced by arsenic is mediated by increased cellular levels of ROS. This conclusion is problematic because this study only measured the basal ROS levels in transformed and parent cells and did not investigate the role of ROS in the process of arsenic-induced cell transformation. The levels of ROS in arsenic-transformed cells represent the result and not the cause of cell transformation. Thus question concerning whether ROS are important in arsenic-induced cell transformation remains to be answered. In the present study, we used expressions of catalase (antioxidant against H{sub 2}O{sub 2}) and superoxide dismutase 2 (SOD2, antioxidant against O{sub 2}{sup ·−}) to decrease ROS level and investigated their role in the process of arsenic-induced cell transformation. Our results show that inhibition of ROS by antioxidant enzymes decreased arsenic-induced cell transformation, demonstrating that ROS are important in this process. We have also shown that in arsenic-transformed cells, ROS generation was lower and levels of antioxidants are higher than those in parent cells, in a disagreement with the previous

  10. Role of reactive oxygen species in arsenic-induced transformation of human lung bronchial epithelial (BEAS-2B) cells

    International Nuclear Information System (INIS)

    Zhang, Zhuo; Pratheeshkumar, Poyil; Budhraja, Amit; Son, Young-Ok; Kim, Donghern; Shi, Xianglin

    2015-01-01

    Highlights: • Short term exposure of cells to arsenic causes ROS generation. • Chronical exposure of cells to arsenic causes malignant cell transformation. • Inhibition of ROS generation reduces cell transformation by arsenic. • Arsenic-transformed cells exhibit reduced capacity of generating ROS. • Arsenic-transformed cells exhibit increased levels of antioxidants. - Abstract: Arsenic is an environmental carcinogen, its mechanisms of carcinogenesis remain to be investigated. Reactive oxygen species (ROS) are considered to be important. A previous study (Carpenter et al., 2011) has measured ROS level in human lung bronchial epithelial (BEAS-2B) cells and arsenic-transformed BEAS-2B cells and found that ROS levels were higher in transformed cells than that in parent normal cells. Based on these observations, the authors concluded that cell transformation induced by arsenic is mediated by increased cellular levels of ROS. This conclusion is problematic because this study only measured the basal ROS levels in transformed and parent cells and did not investigate the role of ROS in the process of arsenic-induced cell transformation. The levels of ROS in arsenic-transformed cells represent the result and not the cause of cell transformation. Thus question concerning whether ROS are important in arsenic-induced cell transformation remains to be answered. In the present study, we used expressions of catalase (antioxidant against H 2 O 2 ) and superoxide dismutase 2 (SOD2, antioxidant against O 2 ·− ) to decrease ROS level and investigated their role in the process of arsenic-induced cell transformation. Our results show that inhibition of ROS by antioxidant enzymes decreased arsenic-induced cell transformation, demonstrating that ROS are important in this process. We have also shown that in arsenic-transformed cells, ROS generation was lower and levels of antioxidants are higher than those in parent cells, in a disagreement with the previous report. The

  11. Cell viability, reactive oxygen species, apoptosis, and necrosis in myoblast cultures exposed to low-level infrared laser.

    Science.gov (United States)

    Alexsandra da Silva Neto Trajano, Larissa; da Silva, Camila Luna; de Carvalho, Simone Nunes; Cortez, Erika; Mencalha, André Luiz; de Souza da Fonseca, Adenilson; Stumbo, Ana Carolina

    2016-07-01

    Low-level infrared laser is considered safe and effective for treatment of muscle injuries. However, the mechanism involved on beneficial effects of laser therapy are not understood. The aim was to evaluate cell viability, reactive oxygen species, apoptosis, and necrosis in myoblast cultures exposed to low-level infrared laser at therapeutic fluences. C2C12 myoblast cultures at different (2 and 10 %) fetal bovine serum (FBS) concentrations were exposed to low-level infrared laser (808 nm, 100 mW) at different fluences (10, 35, and 70 J/cm(2)) and evaluated after 24, 48, and 72 h. Cell viability was evaluated by WST-1 assay; reactive oxygen species (ROS), apoptosis, and necrosis were evaluated by flow cytometry. Cell viability was decreased atthe lowest FBS concentration. Laser exposure increased the cell viability in myoblast cultures at 2 % FBS after 48 and 72 h, but no significant increase in ROS was observed. Apoptosis was decreased at the higher fluence and necrosis was increased at lower fluence in myoblast cultures after 24 h of laser exposure at 2 % FBS. No laser-induced alterations were obtained at 10 % FBS. Results show that level of reactive oxygen species is not altered, at least to those evaluated in this study, but low-level infrared laser exposure affects cell viability, apoptosis, and necrosis in myoblast cultures depending on laser fluence and physiologic conditions of cells.

  12. On the Effects of Reactive Oxygen Species and Nitric Oxide on Red Blood Cell Deformability

    Directory of Open Access Journals (Sweden)

    Lukas Diederich

    2018-05-01

    Full Text Available The main function of red blood cells (RBCs is the transport of respiratory gases along the vascular tree. To fulfill their task, RBCs are able to elastically deform in response to mechanical forces and, pass through the narrow vessels of the microcirculation. Decreased RBC deformability was observed in pathological conditions linked to increased oxidative stress or decreased nitric oxide (NO bioavailability, like hypertension. Treatments with oxidants and with NO were shown to affect RBC deformability ex vivo, but the mechanisms underpinning these effects are unknown. In this study we investigate whether changes in intracellular redox status/oxidative stress or nitrosation reactions induced by reactive oxygen species (ROS or NO may affect RBC deformability. In a case-control study comparing RBCs from healthy and hypertensive participants, we found that RBC deformability was decreased, and levels of ROS were increased in RBCs from hypertensive patients as compared to RBCs from aged-matched healthy controls, while NO levels in RBCs were not significantly different. To study the effects of oxidants on RBC redox state and deformability, RBCs from healthy volunteers were treated with increasing concentrations of tert-butylhydroperoxide (t-BuOOH. We found that high concentrations of t-BuOOH (≥ 1 mM significantly decreased the GSH/GSSG ratio in RBCs, decreased RBC deformability and increased blood bulk viscosity. Moreover, RBCs from Nrf2 knockout (KO mice, a strain genetically deficient in a number of antioxidant/reducing enzymes, were more susceptible to t-BuOOH-induced impairment in RBC deformability as compared to wild type (WT mice. To study the role of NO in RBC deformability we treated RBC suspensions from human volunteers with NO donors and nitrosothiols and analyzed deformability of RBCs from mice lacking the endothelial NO synthase (eNOS. We found that NO donors induced S-nitrosation of the cytoskeletal protein spectrin, but did not affect

  13. HIV antiretroviral drug combination induces endothelial mitochondrial dysfunction and reactive oxygen species production, but not apoptosis

    International Nuclear Information System (INIS)

    Jiang Bo; Hebert, Valeria Y.; Li, Yuchi; Mathis, J. Michael; Alexander, J. Steven; Dugas, Tammy R.

    2007-01-01

    Numerous reports now indicate that HIV patients administered long-term antiretroviral therapy (ART) are at a greater risk for developing cardiovascular diseases. Endothelial dysfunction is an initiating event in atherogenesis and may contribute to HIV-associated atherosclerosis. We previously reported that ART induces direct endothelial dysfunction in rodents. In vitro treatment of human umbilical vein endothelial cells (HUVEC) with ART indicated endothelial mitochondrial dysfunction and a significant increase in the production of reactive oxygen species (ROS). In this study, we determined whether ART-induced endothelial dysfunction is mediated via mitochondria-derived ROS and whether this mitochondrial injury culminates in endothelial cell apoptosis. Two major components of ART combination therapy, a nucleoside reverse transcriptase inhibitor and a protease inhibitor, were tested, using AZT and indinavir as representatives for each. Microscopy utilizing fluorescent indicators of ROS and mitochondria demonstrated the mitochondrial localization of ART-induced ROS. MnTBAP, a cell-permeable metalloporphyrin antioxidant, abolished ART-induced ROS production. As a final step in confirming the mitochondrial origin of the ART-induced ROS, HUVEC were transduced with a cytosolic- compared to a mitochondria-targeted catalase. Transduction with the mitochondria-targeted catalase was more effective than cytoplasmic catalase in inhibiting the ROS and 8-isoprostane (8-iso-PGF 2α ) produced after treatment with either AZT or indinavir. However, both mitochondrial and cytoplasmic catalase attenuated ROS and 8-iso-PGF 2α production induced by the combination treatment, suggesting that in this case, the formation of cytoplasmic ROS may also occur, and thus, that the mechanism of toxicity in the combination treatment group may be different compared to treatment with AZT or indinavir alone. Finally, to determine whether ART-induced mitochondrial dysfunction and ROS production

  14. Adrenaline and reactive oxygen species elicit proteome and energetic metabolism modifications in freshly isolated rat cardiomyocytes

    International Nuclear Information System (INIS)

    Costa, Vera Marisa; Silva, Renata; Tavares, Ludgero Canario; Vitorino, Rui; Amado, Francisco; Carvalho, Felix; Bastos, Maria de Lourdes; Carvalho, Marcia; Carvalho, Rui Albuquerque; Remiao, Fernando

    2009-01-01

    The sustained elevation of plasma and interstitial catecholamine levels, namely adrenaline (ADR), and the generation of reactive oxygen species (ROS) are well recognized hallmarks of several cardiopathologic conditions, like cardiac ischemia/reperfusion (I/R) and heart failure (HF). The present work aimed to investigate the proteomics and energetic metabolism of cardiomyocytes incubated with ADR and/or ROS. To mimic pathologic conditions, freshly isolated calcium-tolerant cardiomyocytes from adult rat were incubated with ADR alone or in the presence of a system capable of generating ROS [(xanthine with xanthine oxidase) (XXO)]. Two-dimensional electrophoresis with matrix-assisted laser desorption/ionization and time-of-flight mass spectrometer analysis were used to define protein spot alterations in the cardiomyocytes incubated with ADR and/or ROS. Moreover, the energetic metabolism and the activity of mitochondrial complexes were evaluated by nuclear magnetic resonance and spectrophotometric determinations, respectively. The protein extract was mainly constituted by cardiac mitochondrial proteins and the alterations found were included in five functional classes: (i) structural proteins, notably myosin light chain-2; (ii) redox regulation proteins, in particular superoxide dismutase (SOD); (iii) energetic metabolism proteins, encompassing ATP synthase alpha chain and dihydrolipoyllysine-residue acetyltransferase component of pyruvate dehydrogenase complex; (iv) stress response proteins, like the heat shock proteins; and (v) regulatory proteins, like cytochrome c and voltage-dependent anion channel 1. The XXO system elicited alterations in cardiac contractile proteins, as they showed high levels of cleavage, and also altered energetic metabolism, through increased lactate and alanine levels. The cardiomyocytes incubation with ADR resulted in an accentuated increase in mitochondrial complexes activity and the decrease in alanine/lactate ratio, thus reflecting a high

  15. Photochemical Cycling of Reactive Oxygen Species in Hydrothermal Springs: Impacts on Biosignature Preservation

    Science.gov (United States)

    Mave, M. A.; Hinman, N. W.; Stevens, L.

    2017-12-01

    Biosignatures can be preserved via rapid entombment by aqueous minerals in a system. Wilson et al. (2000) found that high UV flux leads to increased production of reactive oxygen species (ROS), which promote iron (Fe) oxidation, and possible accumulation on microbial surfaces, leading to detectable microfossils. Hydrogen peroxide (H2O2) is a measurable ROS that serves as proxy for less stable ROS. Overall diel cycling of H2O2 is likely controlled by changes in photoreactive speciation of Fe (McKnight et al., 1988) in Fe-rich systems. To test this hypothesis, we conducted a 48-hour photochemical field study of Elk Pool in the Norris Geyser Basin at Yellowstone National Park in July, 2017 in which we measured UVA and UVB, along with H2O2 via the scopoletin fluorescence quenching method (Holm et al., 1987). Measurements were taken every few hours, and we found that maximum ROS production occurred during maximum UV irradiation. We also ran several experiments on-site in which we collected and altered spring water to either inactivate or catalyze naturally occurring reactions as well as to isolate primary mechanisms responsible for production of H2O2. Experiments were run in UV permeable Whirlpak bags and Fisherbrand tubes. Elk Pool showed only trace Fe content (pH 4) at the time of our study, so Fe-silica coated petrographic slides were added to the tube experiments (Fe-added experiments). Both sets of experiments included filtered and unfiltered spring water to differentiate biotic from abiotic mechanisms, and both UV-exposed and dark controls to separate UV-induced mechanisms for ROS formation. UV-exposed water always had greater ROS than dark experiments. Filtered spring water had higher ROS concentrations than unfiltered water, except when Fe was added. In the Fe-added experiments, unfiltered spring water had slightly greater ROS production relative to filtered water and had the lowest pH and highest aqueous Fe content after 7 hours. All Fe-added experiments showed

  16. Occurrence of anthracnose on highbush blueberry caused by colletotrichum species in Korea.

    Science.gov (United States)

    Kim, Wan Gyu; Hong, Sung Kee; Choi, Hyo Won; Lee, Young Kee

    2009-12-01

    A total of 82 isolates of Colletotrichum species were obtained from anthracnose symptoms of highbush blueberry trees grown in the Gochang area of Korea during a disease survey in 2008. Out of the isolates, 75 were identified as Colletotrichum gloeosporioides and the others as C. acutatum based on their morphological and cultural characteristics. Twenty six of C. gloeosporioides isolates produced their teleomorph Glomerella cingulata in PDA culture. Three isolates of each C. gloeosporioides and C. acutatum caused anthracnose symptoms on the leaves by artificial inoculation, which were similar to what was observed in the orchards. Previously in Korea, only C. gloeosporioides has been reported as causing anthracnose in blueberries. This is the first report that C. acutatum causes anthracnose in the highbush blueberry in Korea.

  17. Tetraspanin is required for generation of reactive oxygen species by the dual oxidase system in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Hiroki Moribe

    2012-09-01

    Full Text Available Reactive oxygen species (ROS are toxic but essential molecules responsible for host defense and cellular signaling. Conserved NADPH oxidase (NOX family enzymes direct the regulated production of ROS. Hydrogen peroxide (H(2O(2 generated by dual oxidases (DUOXs, a member of the NOX family, is crucial for innate mucosal immunity. In addition, H(2O(2 is required for cellular signaling mediated by protein modifications, such as the thyroid hormone biosynthetic pathway in mammals. In contrast to other NOX isozymes, the regulatory mechanisms of DUOX activity are less understood. Using Caenorhabditis elegans as a model, we demonstrate that the tetraspanin protein is required for induction of the DUOX signaling pathway in conjunction with the dual oxidase maturation factor (DUOXA. In the current study, we show that genetic mutation of DUOX (bli-3, DUOXA (doxa-1, and peroxidase (mlt-7 in C. elegans causes the same defects as a tetraspanin tsp-15 mutant, represented by exoskeletal deficiencies due to the failure of tyrosine cross-linking of collagen. The deficiency in the tsp-15 mutant was restored by co-expression of bli-3 and doxa-1, indicating the involvement of tsp-15 in the generation of ROS. H(2O(2 generation by BLI-3 was completely dependent on TSP-15 when reconstituted in mammalian cells. We also demonstrated that TSP-15, BLI-3, and DOXA-1 form complexes in vitro and in vivo. Cell-fusion-based analysis suggested that association with TSP-15 at the cell surface is crucial for BLI-3 activation to release H(2O(2. This study provides the first evidence for an essential role of tetraspanin in ROS generation.

  18. Involvement of reactive oxygen species in endosperm cap weakening and embryo elongation growth during lettuce seed germination

    Science.gov (United States)

    Zhang, Yu; Chen, Bingxian; Xu, Zhenjiang; Shi, Zhaowan; Chen, Shanli; Huang, Xi; Chen, Jianxun; Wang, Xiaofeng

    2014-01-01

    Endosperm cap (CAP) weakening and embryo elongation growth are prerequisites for the completion of lettuce seed germination. Although it has been proposed that the cell wall loosening underlying these processes results from an enzymatic mechanism, it is still unclear which enzymes are involved. Here it is shown that reactive oxygen species (ROS), which are non-enzymatic factors, may be involved in the two processes. In Guasihong lettuce seeds imbibed in water, O2·– and H2O2 accumulated and peroxidase activity increased in the CAP, whereas its puncture force decreased. In addition, in the radicle, the increase in embryo growth potential was accompanied by accumulation of O2·– and an increase in peroxidase activity. Imbibing seeds in 0.3% sodium dichloroisocyanurate (SDIC) reduced endosperm viability and the levels of O2·–, H2O2, and peroxidase activity in the CAP, whereas the decrease in its puncture force was inhibited. However, in the embryo, SDIC did not affect the accumulation of O2·–, peroxidase activity, and the embryo growth potential. As a result, SDIC caused atypical germination, in which the endosperm ruptured at the boundary between the CAP and lateral endosperm. ROS scavengers and ROS generation inhibitors inhibited the CAP weakening and also decreased the embryo growth potential, thus decreasing the percentage of seed germination. Exogenous ROS and ROS generation inducers increased the percentage of CAP rupture to some extent, and the addition of H2O2 to 0.3% SDIC enabled some seeds to undergo typical germination. PMID:24744430

  19. Hypoxia dysregulates the production of adiponectin and plasminogen activator inhibitor-1 independent of reactive oxygen species in adipocytes

    International Nuclear Information System (INIS)

    Chen Baoying; Lam, Karen S.L.; Wang Yu; Wu Donghai; Lam, Michael C.; Shen Jiangang; Wong Laiching; Hoo, Ruby L.C.; Zhang Jialiang; Xu Aimin

    2006-01-01

    Low plasma levels of adiponectin (hypoadiponectinemia) and elevated circulating concentrations of plasminogen activator inhibitor (PAI)-1 are causally associated with obesity-related insulin resistance and cardiovascular disease. However, the mechanism that mediates the aberrant production of these two adipokines in obesity remains poorly understood. In this study, we investigated the effects of hypoxia and reactive oxygen species (ROS) on production of adiponectin and PAI-1 in 3T3-L1 adipocytes. Quantitative PCR and immunoassays showed that ambient hypoxia markedly suppressed adiponectin mRNA expression and its protein secretion, and increased PAI-1 production in mature adipocytes. Dimethyloxallyl glycine, a stabilizer of hypoxia-inducible factor 1α (HIF-1α), mimicked the hypoxia-mediated modulations of these two adipokines. Hypoxia caused a modest elevation of ROS in adipocytes. However, ablation of intracellular ROS by antioxidants failed to alleviate hypoxia-induced aberrant production of adiponectin and PAI-1. On the other hand, the antioxidants could reverse hydrogen peroxide (H 2 O 2 )-induced dysregulation of adiponectin and PAI-1 production. H 2 O 2 treatment decreased the expression levels of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein (C/EBPα), but had no effect on HIF-1α, whereas hypoxia stabilized HIF-1α and decreased expression of C/EBPα, but not PPARγ. Taken together, these data suggest that hypoxia and ROS decrease adiponectin production and augment PAI-1 expression in adipocytes via distinct signaling pathways. These effects may contribute to hypoadiponectinemia and elevated PAI-1 levels in obesity, type 2 diabetes, and cardiovascular diseases

  20. A role for human mitochondrial complex II in the production of reactive oxygen species in human skin

    Directory of Open Access Journals (Sweden)

    Alasdair Anderson

    2014-01-01

    Full Text Available The mitochondrial respiratory chain is a major generator of cellular oxidative stress, thought to be an underlying cause of the carcinogenic and ageing process in many tissues including skin. Previous studies of the relative contributions of the respiratory chain (RC complexes I, II and III towards production of reactive oxygen species (ROS have focussed on rat tissues and certainly not on human skin which is surprising as this tissue is regularly exposed to UVA in sunlight, a potent generator of cellular oxidative stress. In a novel approach we have used an array of established specific metabolic inhibitors and DHR123 fluorescence to study the relative roles of the mitochondrial RC complexes in cellular ROS production in 2 types of human skin cells. These include additional enhancement of ROS production by exposure to physiological levels of UVA. The effects within epidermal and dermal derived skin cells are compared to other tissue cell types as well as those harbouring a compromised mitochondrial status (Rho-zero A549. The results show that the complex II inhibitor, TTFA, was the only RC inhibitor to significantly increase UVA-induced ROS production in both skin cell types (P<0.05 suggesting that the role of human skin complex II in terms of influencing ROS production is more important than previously thought particularly in comparison to liver cells. Interestingly, two-fold greater maximal activity of complex II enzyme was observed in both skin cell types compared to liver (P<0.001. The activities of RC enzymes appear to decrease with increasing age and telomere length is correlated with ageing. Our study showed that the level of maximal complex II activity was higher in the MRC5/hTERT (human lung fibroblasts transfected with telomerase cells than the corresponding wild type cells (P=0.0012 which can be considered (in terms of telomerase activity as models of younger and older cells respectively.

  1. Hydroxylated polychlorinated biphenyls increase reactive oxygen species formation and induce cell death in cultured cerebellar granule cells

    International Nuclear Information System (INIS)

    Dreiem, Anne; Rykken, Sidsel; Lehmler, Hans-Joachim; Robertson, Larry W.; Fonnum, Frode

    2009-01-01

    Polychlorinated biphenyls (PCBs) are persistent organic pollutants that bioaccumulate in the body, however, they can be metabolized to more water-soluble products. Although they are more readily excreted than the parent compounds, some of the metabolites are still hydrophobic and may be more available to target tissues, such as the brain. They can also cross the placenta and reach a developing foetus. Much less is known about the toxicity of PCB metabolites than about the parent compounds. In the present study, we have investigated the effects of eight hydroxylated (OH) PCB congeners (2'-OH PCB 3, 4-OH PCB 14, 4-OH PCB 34, 4'-OH PCB 35, 4-OH PCB 36, 4'-OH PCB 36, 4-OH PCB 39, and 4'-OH PCB 68) on reactive oxygen species (ROS) formation and cell viability in rat cerebellar granule cells. We found that, similar to their parent compounds, OH-PCBs are potent ROS inducers with potency 4-OH PCB 14 < 4-OH PCB 36 < 4-OH PCB 34 < 4'-OH PCB 36 < 4'-OH PCB 68 < 4-OH PCB 39 < 4'-OH PCB 35. 4-OH PCB 36 was the most potent cell death inducer, and caused apoptotic or necrotic morphology depending on concentration. Inhibition of ERK1/2 kinase with U0126 reduced both cell death and ROS formation, suggesting that ERK1/2 activation is involved in OH-PCB toxicity. The results indicate that the hydroxylation of PCBs may not constitute a detoxification reaction. Since OH-PCBs like their parent compounds are retained in the body and may be more widely distributed to sensitive tissues, it is important that not only the levels of the parent compounds but also the levels of their metabolites are taken into account during risk assessment of PCBs and related compounds.

  2. Dissolution and reactive oxygen species generation of inhaled cemented tungsten carbide particles in artificial human lung fluids

    International Nuclear Information System (INIS)

    Stefaniak, A B; Leonard, S S; Hoover, M D; Virji, M A; Day, G A

    2009-01-01

    Inhalation of both cobalt (Co) and tungsten carbide (WC) particles is associated with development of hard metal lung disease (HMD) via generation of reactive oxygen species (ROS), whereas Co alone is sufficient to cause asthma via solubilization and hapten formation. We characterized bulk and aerodynamically size-separated W, WC, Co, spray dryer (pre-sintered), and chamfer grinder (post-sintered) powders. ROS generation was measured in the murine RAW 264.7 cell line using electron spin resonance. When dose was normalized to surface area, hydroxyl radical generation was independent of particle size, which suggests that particle surface chemistry may be an important exposure factor. Chamfer grinder particles generated the highest levels of ROS, consistent with the hypothesis that intimate contact of metals is important for ROS generation. In artificial extracellular lung fluid, alkylbenzyldimethylammonium chloride (ABDC), added to prevent mold growth during experiments, did not influence dissolution of Co (44.0±5.2 vs. 48.3±6.4%); however, dissolution was higher (p<0.05) in the absence of phosphate (62.0±5.4 vs. 48.3±6.4%). In artificial macrophage phagolysosomal fluid, dissolution of Co (36.2±10.4%) does not appear to be influenced (p=0.30) by the absence of glycine (29.8±2.1%), phosphate (39.6±8.6%), or ABDC (44.0±10.5%). These results aid in assessing and understanding Co and W inhalation dosimetry.

  3. Necrostatin-1 protects against reactive oxygen species (ROS-induced hepatotoxicity in acetaminophen-induced acute liver failure

    Directory of Open Access Journals (Sweden)

    Kenji Takemoto

    2014-01-01

    Full Text Available Excessive acetaminophen (APAP use is one of the most common causes of acute liver failure. Various types of cell death in the damaged liver are linked to APAP-induced hepatotoxicity, and, of these, necrotic cell death of hepatocytes has been shown to be involved in disease pathogenesis. Until recently, necrosis was commonly considered to be a random and unregulated form of cell death; however, recent studies have identified a previously unknown form of programmed necrosis called receptor-interacting protein kinase (RIPK-dependent necrosis (or necroptosis, which is controlled by the kinases RIPK1 and RIPK3. Although RIPK-dependent necrosis has been implicated in a variety of disease states, including atherosclerosis, myocardial organ damage, stroke, ischemia–reperfusion injury, pancreatitis, and inflammatory bowel disease. However its involvement in APAP-induced hepatocyte necrosis remains elusive. Here, we showed that RIPK1 phosphorylation, which is a hallmark of RIPK-dependent necrosis, was induced by APAP, and the expression pattern of RIPK1 and RIPK3 in the liver overlapped with that of CYP2E1, whose activity around the central vein area has been demonstrated to be critical for the development of APAP-induced hepatic injury. Moreover, a RIPK1 inhibitor ameliorated APAP-induced hepatotoxicity in an animal model, which was underscored by significant suppression of the release of hepatic enzymes and cytokine expression levels. RIPK1 inhibition decreased reactive oxygen species levels produced in APAP-injured hepatocytes, whereas CYP2E1 expression and the depletion rate of total glutathione were unaffected. Of note, RIPK1 inhibition also conferred resistance to oxidative stress in hepatocytes. These data collectively demonstrated a RIPK-dependent necrotic mechanism operates in the APAP-injured liver and inhibition of this pathway may be beneficial for APAP-induced fulminant hepatic failure.

  4. Prooxidant action of furanone compounds: implication of reactive oxygen species in the metal-dependent strand breaks and the formation of 8-hydroxy-2'-deoxyguanosine in DNA.

    Science.gov (United States)

    Murakami, K; Haneda, M; Makino, T; Yoshino, M

    2007-07-01

    Prooxidant properties of furanone compounds including 2,5-furanone (furaneol, 4-hydroxy-2,5-dimethyl-furan-3-one), 4,5-furanone (4,5-dimethyl-3-hydroxy-2(5H)-furanone) (sotolone) and cyclotene (2-hydroxy-3-methyl-2-cyclopenten-1-one) were analyzed in relation to the metal-reducing activity. Only 2.5-furanone known as a "strawberry or pineapple furanone" inactivated aconitase the most sensitive enzyme to active oxygen in the presence of ferrous sulfate, suggesting the furaneol/iron-mediated generation of reactive oxygen species. 2,5-Furanone caused strand scission of pBR322 DNA in the presence of copper. Treatment of calf thymus DNA with 2,5-furanone plus copper produced 8-hydroxy-2'-deoxyguanosine in DNA. 2,5-Furanone showed a potent copper-reducing activity, and thus, DNA strand breaks and the formation of 8-hydroxy-2'-deoxyguanosine by 2,5-furanone can be initiated by the production of superoxide radical through the reduction of cupric ion to cuprous ion, resulting in the conversion to hydrogen peroxide and hydroxyl radical. However, an isomer and analog of 2,5-furanone, 4,5-furanone and cyclotene, respectively, did not show an inactivation of aconitase, DNA injuries including strand breakage and the formation of 8-hydroxy-2'-deoxyguanosine, and copper-reducing activity. Cytotoxic effect of 2,5-furanone with hydroxyketone structure can be explained by its prooxidant properties: furaneol/transition metal complex generates reactive oxygen species causing the inactivation of aconitase and the formation of DNA base damage by hydroxyl radical.

  5. Morphological and molecular characterization of Cladosporium cladosporioides species complex causing pecan tree leaf spot.

    Science.gov (United States)

    Walker, C; Muniz, M F B; Rolim, J M; Martins, R R O; Rosenthal, V C; Maciel, C G; Mezzomo, R; Reiniger, L R S

    2016-09-16

    The objective of this study was to characterize species of the Cladosporium cladosporioides complex isolated from pecan trees (Carya illinoinensis) with symptoms of leaf spot, based on morphological and molecular approaches. Morphological attributes were assessed using monosporic cultures on potato dextrose agar medium, which were examined for mycelial growth, sporulation, color, and conidia and ramoconidia size. Molecular characterization comprised isolation of DNA and subsequent amplification of the translation elongation factor 1α (TEF-1α) region. Three species of the C. cladosporioides complex were identified: C. cladosporioides, Cladosporium pseudocladosporioides, and Cladosporium subuliforme. Sporulation was the most important characteristic differentiating species of this genus. However, morphological features must be considered together with molecular analysis, as certain characters are indistinguishable between species. TEF-1αcan be effectively used to identify and group isolates belonging to the C. cladosporioides complex. The present study provides an important example of a methodology to ascertain similarity between isolates of this complex causing leaf spot in pecan trees, which should facilitate future pathogenicity studies.

  6. Fusarium species causing eumycetoma: Report of two cases and comprehensive review of the literature.

    Science.gov (United States)

    Al-Hatmi, Abdullah M S; Bonifaz, Alexandro; Tirado-Sánchez, Andrés; Meis, Jacques F; de Hoog, G Sybren; Ahmed, Sarah A

    2017-03-01

    Recently, mycetoma was added to the World Health Organization's list of neglected tropical disease priorities. Fusarium as a genus has been reported to cause eumycetoma, but little is known about the species involved in this infection and their identification. In this study, molecular tools were applied to identify Fusarium agents from human eumycetoma cases. The partial translation elongation factor 1-alpha (TEF-1α) gene was used as diagnostic parameter. Two additional cases of eumycetoma, due to F. keratoplasticum and F. pseudensiforme, respectively, are presented. A systematic literature review was performed to assess general features, identification, treatment and outcome of eumycetoma infections due to Fusarium species. Of the 20 reviewed patients, the majority (75%) were male. Most agents belonged to the F. solani species complex, ie F. keratoplasticum, F. pseudensiforme, and an undescribed lineage of F. solani. In addition, F. thapsinum, a member of Fusarium fujikuroi species complex was encountered. The main antifungal drugs used were itraconazole, ketoconazole and amphotericin B, but cure rates were low (15%). Partial response or relapse was observed in some cases, and a case ended in amputation. Clinical management of eumycetoma due to Fusarium is complex and combination therapy might be required to increase cure rates. © 2016 Blackwell Verlag GmbH.

  7. Generation of reactive oxygen species and charge carriers in plasmonic photocatalytic Au@TiO2 nanostructures with enhanced activity.

    Science.gov (United States)

    He, Weiwei; Cai, Junhui; Jiang, Xiumei; Yin, Jun-Jie; Meng, Qingbo

    2018-06-13

    The combination of semiconductor and plasmonic nanostructures, endowed with high efficiency light harvesting and surface plasmon confinement, has been a promising way for efficient utilization of solar energy. Although the surface plasmon resonance (SPR) assisted photocatalysis has been extensively studied, the photochemical mechanism, e.g. the effect of SPR on the generation of reactive oxygen species and charge carriers, is not well understood. In this study, we take Au@TiO2 nanostructures as a plasmonic photocatalyst to address this critical issue. The Au@TiO2 core/shell nanostructures with tunable SPR property were synthesized by the templating method with post annealing thermal treatment. It was found that Au@TiO2 nanostructures exhibit enhanced photocatalytic activity in either sunlight or visible light (λ > 420 nm). Electron spin resonance spectroscopy with spin trapping and spin labeling was used to investigate the enhancing effect of Au@TiO2 on the photo-induced reactive oxygen species and charge carriers. The formation of Au@TiO2 core/shell nanostructures resulted in a dramatic increase in light-induced generation of hydroxyl radicals, singlet oxygen, holes and electrons, as compared with TiO2 alone. This enhancement under visible light (λ > 420 nm) irradiation may be dominated by SPR induced local electrical field enhancement, while the enhancement under sunlight irradiation is dominated by the higher electron transfer from TiO2 to Au. These results unveiled that the superior photocatalytic activity of Au@TiO2 nanostructures correlates with enhanced generation of reactive oxygen species and charge carriers.

  8. The study of excited oxygen molecule gas species production and quenching on thermal protection system materials

    Science.gov (United States)

    Nordine, Paul C.; Fujimoto, Gordon T.; Greene, Frank T.

    1987-01-01

    The detection of excited oxygen and ozone molecules formed by surface catalyzed oxygen atom recombination and reaction was investigated by laser induced fluorescence (LIF), molecular beam mass spectrometric (MBMS), and field ionization (FI) techniques. The experiment used partially dissociated oxygen flows from a microwave discharge at pressures in the range from 60 to 400 Pa or from an inductively coupled RF discharge at atmospheric pressure. The catalyst materials investigated were nickel and the reaction cured glass coating used for Space Shuttle reusable surface insulation tiles. Nonradiative loss processes for the laser excited states makes LIF detection of O2 difficult such that formation of excited oxygen molecules could not be detected in the flow from the microwave discharge or in the gaseous products of atom loss on nickel. MBMS experiments showed that ozone was a product of heterogeneous O atom loss on nickel and tile surfaces at low temperatures and that ozone is lost on these materials at elevated temperatures. FI was separately investigated as a method by which excited oxygen molecules may be conveniently detected. Partial O2 dissociation decreases the current produced by FI of the gas.

  9. Environmental science: Oceans lose oxygen

    Science.gov (United States)

    Gilbert, Denis

    2017-02-01

    Oxygen is essential to most life in the ocean. An analysis shows that oxygen levels have declined by 2% in the global ocean over the past five decades, probably causing habitat loss for many fish and invertebrate species. See Letter p.335

  10. The Causes and Evolutionary Consequences of Mixed Singing in Two Hybridizing Songbird Species (Luscinia spp.)

    Science.gov (United States)

    Vokurková, Jana; Petrusková, Tereza; Reifová, Radka; Kozman, Alexandra; Mořkovský, Libor; Kipper, Silke; Weiss, Michael; Reif, Jiří; Dolata, Paweł T.; Petrusek, Adam

    2013-01-01

    Bird song plays an important role in the establishment and maintenance of prezygotic reproductive barriers. When two closely related species come into secondary contact, song convergence caused by acquisition of heterospecific songs into the birds’ repertoires is often observed. The proximate mechanisms responsible for such mixed singing, and its effect on the speciation process, are poorly understood. We used a combination of genetic and bioacoustic analyses to test whether mixed singing observed in the secondary contact zone of two passerine birds, the Thrush Nightingale (Luscinia luscinia) and the Common Nightingale (L. megarhynchos), is caused by introgressive hybridization. We analysed song recordings of both species from allopatric and sympatric populations together with genotype data from one mitochondrial and seven nuclear loci. Semi-automated comparisons of our recordings with an extensive catalogue of Common Nightingale song types confirmed that most of the analysed sympatric Thrush Nightingale males were ‘mixed singers’ that use heterospecific song types in their repertoires. None of these ‘mixed singers’ possessed any alleles introgressed from the Common Nightingale, suggesting that they were not backcross hybrids. We also analysed songs of five individuals with intermediate phenotype, which were identified as F1 hybrids between the Thrush Nightingale female and the Common Nightingale male by genetic analysis. Songs of three of these hybrids corresponded to the paternal species (Common Nightingale) but the remaining two sung a mixed song. Our results suggest that although hybridization might increase the tendency for learning songs from both parental species, interspecific cultural transmission is the major proximate mechanism explaining the occurrence of mixed singers among the sympatric Thrush Nightingales. We also provide evidence that mixed singing does not substantially increase the rate of interspecific hybridization and discuss the

  11. Antifungal Susceptibilities of Candida Species Causing Vulvovaginitis and Epidemiology of Recurrent Cases

    Science.gov (United States)

    Richter, Sandra S.; Galask, Rudolph P.; Messer, Shawn A.; Hollis, Richard J.; Diekema, Daniel J.; Pfaller, Michael A.

    2005-01-01

    There are limited data regarding the antifungal susceptibility of yeast causing vulvovaginal candidiasis, since cultures are rarely performed. Susceptibility testing was performed on vaginal yeast isolates collected from January 1998 to March 2001 from 429 patients with suspected vulvovaginal candidiasis. The charts of 84 patients with multiple positive cultures were reviewed. The 593 yeast isolates were Candida albicans (n = 420), Candida glabrata (n = 112), Candida parapsilosis (n = 30), Candida krusei (n = 12), Saccharomyces cerevisiae ( n = 9), Candida tropicalis (n = 8), Candida lusitaniae (n = 1), and Trichosporon sp. (n = 1). Multiple species suggesting mixed infection were isolated from 27 cultures. Resistance to fluconazole and flucytosine was observed infrequently (3.7% and 3.0%); 16.2% of isolates were resistant to itraconazole (MIC ≥ 1 μg/ml). The four imidazoles (econazole, clotrimazole, miconazole, and ketoconazole) were active: 94.3 to 98.5% were susceptible at ≤1 μg/ml. Among different species, elevated fluconazole MICs (≥16 μg/ml) were only observed in C. glabrata (15.2% resistant [R], 51.8% susceptible-dose dependent [S-DD]), C. parapsilosis (3.3% S-DD), S. cerevisiae (11.1% S-DD), and C. krusei (50% S-DD, 41.7% R, considered intrinsically fluconazole resistant). Resistance to itraconazole was observed among C. glabrata (74.1%), C. krusei (58.3%), S. cerevisiae (55.6%), and C. parapsilosis (3.4%). Among 84 patients with recurrent episodes, non-albicans species were more common (42% versus 20%). A ≥4-fold rise in fluconazole MIC was observed in only one patient with C. parapsilosis. These results support the use of azoles for empirical therapy of uncomplicated candidal vulvovaginitis. Recurrent episodes are more often caused by non-albicans species, for which azole agents are less likely to be effective. PMID:15872235

  12. Potential of Trichoderma species on Helminthosporium causing leaf spot on cane palm, Chrysalidocarpus lutescens.

    Science.gov (United States)

    Jegathambigai, V; Karunaratne, M D S D; Svinningen, A; Mikunthan, G

    2008-01-01

    The cane palm, Chrysalidocarpus lutescens is one among the plant material of the export industries in Sri Lanka. The export quality of C. lutescens was declined due to the repeated occurrence of a leaf spot caused by Helminthosporium. Widespread occurrence of the leaf spot affected the cane palm production and succumb it to a huge setback in the floriculture industry in Sri Lanka. Being an export industry eco-friendly means of disease control was the prime focus for a better management of such vulnerable disease. Trichoderma is a potential bio agent, which has definite role in suppressing the inoculum of Helminthosporium sp. This study aims to evaluate the efficacy of Trichoderma species to control naturally established leaf spot in cane palm under field conditions. Three isolates of T. viride and two isolates of T. harzianum were evaluated. All the Trichoderma species performed significantly in reducing the disease incidence. T. viride + T. harzianum combination (1 x 10(10) cfu/ml) was the best compared to chemical in decreasing the mean disease severity index and improving the frequency of healthy plants. The colour of the leaves regained due to the application of Trichoderma sp. The results revealed that leaf spot incidence was lowered significantly in cane palms treated with Trichoderma species followed by treatment with combination of Trichoderma sp. and fungicides. The fungicide mixture (hexaconozole 50 g/l + Isoprothiolane 400 g/l) failed to lower the disease incidence and had no effect in suppressing the inocula of Helminthosporium, although recommended. Mixing of Trichoderma species with fungicide did not exhibit any additive effect. The combination of different species of Trichoderma would target species of Helminthosporium that exist as a complex group under field conditions. The results also proved that the existence of heterogeneity in Helminthosporium that could be tackled and effectively controlled by a combination of different species of the bio

  13. Primary subacute epiphyseal osteomyelitis caused by Mycobacterium species in young children: a modern diagnostic approach.

    Science.gov (United States)

    El Houmami, N; Minodier, P; Bouvier, C; Seligmann, H; Jouve, J-L; Raoult, D; Fournier, P-E

    2017-05-01

    Primary epiphyseal subacute osteomyelitis (PESAO) caused by Mycobacterium species in young children is poorly recognized. We aimed to define the spectrum of this uncommon condition and to propose a novel diagnostic approach. We performed a systematic review of the literature on the PubMed website by selecting all reports of isolated infantile PESAO caused by Mycobacterium species since 1975. We identified 350 citations, of which 174 were assessed for eligibility based on title and abstract. The full text of 81 eligible citations was screened, and relevant data of 15 children under 4 years of age with mycobacterial PESAO were extracted. These data were pooled with those from our Institution. Data from 16 children were reviewed. The median age was 16 ± 7 months and the male:female ratio 1.7. The knee was the most common infection site (94%). The diagnosis of mycobacterial disease was delayed in all cases (range, 2 weeks to 6 months), and initially presumed by histology in 15 children (94%). Microbiologically proven diagnosis was confirmed by bone cultures in 8 of the 15 children (53%), and by specific PCR in 2 of the 3 culture-negative bone specimens (67%). Three children experienced long-term orthopedic complications despite surgical drainage and prolonged antimycobacterial regimens. All recently reported cases came from high-burden tuberculosis areas. Mycobacterium species contribute to the burden of infantile PESAO in endemic tuberculosis areas and may cause growth disturbances. We argue in favor of the early recognition of mycobacterial disease by specific molecular assays in children with infantile PESAO living in high-burden areas.

  14. Sunlight creates oxygenated species in water-soluble fractions of Deepwater horizon oil

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Phoebe Z. [Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Chen, Huan [National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); Podgorski, David C. [National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); Future Fuels Institute, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); McKenna, Amy M. [National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); Tarr, Matthew A., E-mail: mtarr@uno.edu [Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States)

    2014-09-15

    Graphical abstract: Sunlight oxygenates petroleum. - Highlights: • Oxidation seen in water-soluble oil fraction after exposure to simulated sunlight. • Oxygen addition occurred across a wide range of carbon number and DBE. • Oil compounds were susceptible to addition of multiple oxygens to each molecule. • Results provide understanding of fate of oil on water after exposure to sunlight. - Abstract: In order to assess the impact of sunlight on oil fate, Macondo well oil from the Deepwater Horizon (DWH) rig was mixed with pure water and irradiated with simulated sunlight. After irradiation, the water-soluble organics (WSO) from the dark and irradiated samples were extracted and characterized by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Liquid–liquid extraction yielded two fractions from dark and irradiated water/oil mixtures: acidic WSOs (negative-ion electrospray (ESI)), and base/neutral WSOs (positive-ion ESI) coupled to FT-ICR MS to catalog molecular-level transformations that occur to Macondo-derived WSOs after solar irradiation. Such direct measure of oil phototransformation has not been previously reported. The most abundant heteroatom class detected in the irradiated WSO acid fractions correspond to molecules that contain five oxygens (O{sub 5}), while the most abundant acids in the dark samples contain two oxygen atoms per molecule (O{sub 2}). Higher-order oxygen classes (O{sub 5}–O{sub 9}) were abundant in the irradiated samples, but <1.5% relative abundance in the dark sample. The increased abundance of higher-order oxygen classes in the irradiated samples relative to the dark samples indicates that photooxidized components of the Macondo crude oil become water-soluble after irradiation. The base/neutral fraction showed decreased abundance of pyridinic nitrogen (N{sub 1}) concurrent with an increased abundance of N{sub 1}O{sub x} classes after irradiation. The predominance of higher

  15. Expression of death-related genes and reactive oxygen species production in Skeletonema tropicum upon exposure to the polyunsaturated aldehyde octadienal

    Directory of Open Access Journals (Sweden)

    Alessandra A. Gallina

    2015-11-01

    Full Text Available The effects of 4E/Z-octadienal (OCTA on ScDSP-1 and ScDSP-2 gene expression and reactive oxygen species (ROS production were investigated in the marine diatom Skeletonema tropicum (formerly costatum using qRTPCR and flow cytometry. ScDSP-1 and ScDSP-2 genes have been previously shown to be involved in cell death in ageing cells and in response to photosynthetic stress. OCTA induced a differential, concentration-dependent DSP gene expression associated to ROS production, 821.6 and 97.7 folds higher for ScDSP-1 and ScDSP-2, respectively. Among the concentrations tested, only 8 μM OCTA, which caused a reduction of 50% in cell concentrations at 24 h, was able to elicit an expression pattern consistent with a signalling role. Interestingly, only intermediate levels of reactive oxygen species (ROS (i.e., 1.5±0.1 increase were observed to be elicited by such concentration. These results suggest that ROS are key components of the molecular cascade triggered by polyunsaturated aldehydes (PUA and leading to cell death. This could have implications for bloom final stages at sea, where PUA may act as effectors of diatom population dynamics through ROS acting as modulators.

  16. Inhibitory effects of polyphenol-enriched extract from Ziyang tea against human breast cancer MCF-7 cells through reactive oxygen species-dependent mitochondria molecular mechanism

    Directory of Open Access Journals (Sweden)

    Wenfeng Li

    2016-07-01

    Full Text Available A polyphenol-enriched extract from selenium-enriched Ziyang green tea (ZTP was selected to evaluate its antitumor effects against human breast cancer MCF-7 cells. In ZTP, (−-epigallocatechin gallate (28.2% was identified as the major catechin, followed by (−-epigallocatechin (5.7% and (−-epicatechin gallate (12.6%. ZTP was shown to inhibit MCF-7 cell proliferation (half maximal inhibitory concentration, IC50 = 172.2 μg/mL by blocking cell-cycle progression at the G0/G1 phase and inducing apoptotic death. Western blotting assay indicated that ZTP induced cell-cycle arrest by upregulation of p53 and reduced the expression of CDK2 in MCF-7 cells. ZTP-caused cell apoptosis was associated with an increase in Bax/Bcl-2 ratio, and activation of caspase-3 and -9. MCF-7 cells treated with ZTP also showed an overproduction of reactive oxygen species, suggesting that reactive oxygen species played an important role in the induction of apoptosis in MCF-7 cells. This is the first report showing that ZTP is a potential novel dietary agent for cancer chemoprevention or chemotherapy.

  17. Holographic monitoring of spatial distributions of singlet oxygen in water

    Science.gov (United States)

    Belashov, A. V.; Bel'tyukova, D. M.; Vasyutinskii, O. S.; Petrov, N. V.; Semenova, I. V.; Chupov, A. S.

    2014-12-01

    A method for monitoring spatial distributions of singlet oxygen in biological media has been developed. Singlet oxygen was generated using Radachlorin® photosensitizer, while thermal disturbances caused by nonradiative deactivation of singlet oxygen were detected by the holographic interferometry technique. Processing of interferograms yields temperature maps that characterize the deactivation process and show the distribution of singlet oxygen species.

  18. Regulation of reactive oxygen and nitrogen species by salicylic acid in rice plants under salinity stress conditions

    Science.gov (United States)

    Mun, Bong-Gyu; Khan, Abdul Latif; Waqas, Muhammad; Kim, Hyun-Ho; Shahzad, Raheem; Imran, Muhammad

    2018-01-01

    This study investigated the regulatory role of exogenous salicylic acid (SA) in rice and its effects on toxic reactive oxygen and nitrogen species during short-term salinity stress. SA application (0.5 and 1.0 mM) during salinity-induced stress (100 mM NaCl) resulted in significantly longer shoot length and higher chlorophyll and biomass accumulation than with salinity stress alone. NaCl-induced reactive oxygen species production led to increased levels of lipid peroxidation in rice plants, which were significantly reduced following SA application. A similar finding was observed for superoxide dismutase; however, catalase (CAT) and ascorbate peroxidase (APX) were significantly reduced in rice plants treated with SA and NaCl alone and in combination. The relative mRNA expression of OsCATA and OsAPX1 was lower in rice plants during SA stress. Regarding nitrogenous species, S-nitrosothiol (SNO) was significantly reduced initially (one day after treatment [DAT]) but then increased in plants subjected to single or combined stress conditions. Genes related to SNO biosynthesis, S-nitrosoglutathione reductase (GSNOR1), NO synthase-like activity (NOA), and nitrite reductase (NIR) were also assessed. The mRNA expression of GSNOR1 was increased relative to that of the control, whereas OsNOA was expressed at higher levels in plants treated with SA and NaCl alone relative to the control. The mRNA expression of OsNR was decreased in plants subjected to single or combination treatment, except at 2 DAT, compared to the control. In conclusion, the current findings suggest that SA can regulate the generation of NaCl-induced oxygen and nitrogen reactive species in rice plants. PMID:29558477

  19. Influence of reactive oxygen species during deposition of iron oxide films by high power impulse magnetron sputtering

    Science.gov (United States)

    Stranak, V.; Hubicka, Z.; Cada, M.; Bogdanowicz, R.; Wulff, H.; Helm, C. A.; Hippler, R.

    2018-03-01

    Iron oxide films were deposited using high power impulse magnetron sputtering (HiPIMS) of an iron cathode in an argon/oxygen gas mixture at different gas pressures (0.5 Pa, 1.5 Pa, and 5.0 Pa). The HiPIMS system was operated at a repetition frequency f  =  100 Hz with a duty cycle of 1%. A main goal is a comparison of film growth during conventional and electron cyclotron wave resonance-assisted HiPIMS. The deposition plasma was investigated by means of optical emission spectroscopy and energy-resolved mass spectrometry. Active oxygen species were detected and their kinetic energy was found to depend on the gas pressure. Deposited films were characterized by means of spectroscopic ellipsometry and grazing incidence x-ray diffraction. Optical properties and crystallinity of as-deposited films were found to depend on the deposition conditions. Deposition of hematite iron oxide films with the HiPIMS-ECWR discharge is attributed to the enhanced production of reactive oxygen species.

  20. Interspecies differences of candida species causing recurrent vulvovaginal candidiasis in response to fluconazole treatment

    Directory of Open Access Journals (Sweden)

    Siamak Naji

    2017-07-01

    Methods: The cross-sectional study was performed at Kowsar Gynecology Center, Motahhari educational hospital and Medical Mycology Center, Faculty of Medicine, Urmia, Iran, from October 2013 to July 2015. Those patients referred to the clinic with symptoms of vaginal discharge, itching or burning that swab samples from endo-exocervix and distal fornix discharge were taken. The vaginal discharge samples submitted to Medical Mycology Center, Urmia School of Medicine for the direct microscopic examination and cultures. Identification at the level of species was performed using CHROMagar Candida and Corn meal agar media. The molecular test polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP used for confirming culture results. For the susceptibility assay, disc diffusion method was performed with fluconazole and clotrimazole. Results: In these study 198 samples collected from patients with symptoms of vulvovaginal candidiasis, 77 vulvovaginal candidiasis cases were identified. Candida species are common in primary and recurrent cases in terms of frequency, Candida albicans (85.7%, Candida krusei (10.2% and Candida glabrata (4.1% were identified respectively. Total of 27 cases of recurrent vulvovaginal candidiasis, 10 cases were resistant to both clotrimazole and fluconazole (37% was observed that the most common species are resistant to treatment were Candida albicans by (82.1%, Candida krusei (14.3% and Candida glabrata (3.6% respectively. Drug resistance in Candida albicans, Candida krusei and Candida glabrata causing recurrent vulvovaginal candidiasis included 69.1%, 75% and 100% respectively. Conclusion: Our findings have shown frequency of resistant non-albicans Candida species to fluconazole and clotrimazole is increasing. There is a considerable difference between Candida albicans and non-albicans species, Candida glabrata for the resistance to fluconazole and clotrimazole.

  1. Reactive oxygen species regulated mitochondria-mediated apoptosis in PC12 cells exposed to chlorpyrifos

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Eun [Department of Pharmacology, College of Medicine, Hanyang University, Seoul (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Park, Jae Hyeon [Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of); Shin, In Chul [Department of Pharmacology, College of Medicine, Hanyang University, Seoul (Korea, Republic of); Koh, Hyun Chul, E-mail: hckoh@hanyang.ac.kr [Department of Pharmacology, College of Medicine, Hanyang University, Seoul (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of)

    2012-09-01

    Reactive oxidative species (ROS) generated by environmental toxicants including pesticides could be one of the factors underlying the neuronal cell damage in neurodegenerative diseases. In this study we found that chlorpyrifos (CPF) induced apoptosis in dopaminergic neuronal components of PC12 cells as demonstrated by the activation of caspases and nuclear condensation. Furthermore, CPF also reduced the tyrosine hydroxylase-positive immunoreactivity in substantia nigra of the rat. In addition, CPF induced inhibition of mitochondrial complex I activity. Importantly, N-acetyl cysteine (NAC) treatment effectively blocked apoptosis via the caspase-9 and caspase-3 pathways while NAC attenuated the inhibition of mitochondrial complex I activity as well as the oxidative metabolism of dopamine (DA). These results demonstrated that CPF-induced apoptosis was involved in mitochondrial dysfunction through the production of ROS. In the response of cellular antioxidant systems to CPF, we found that CPF treatment increased HO-1 expression while the expression of CuZnSOD and MnSOD was reduced. In addition, we found that CPF treatment activated MAPK pathways, including ERK 1/2, the JNK, and the p38 MAP kinase in a time-dependent manner. NAC treatment abolished MAPK phosphorylation caused by CPF, indicating that ROS are upstream signals of MAPK. Interestingly, MAPK inhibitors abolished cytotoxicity and reduced ROS generation by CPF treatment. Our results demonstrate that CPF induced neuronal cell death in part through MAPK activation via ROS generation, suggesting its potential to generate oxidative stress via mitochondrial damage and its involvement in oxidative stress-related neurodegenerative disease. -- Highlights: ► Chlorpyrifos induces apoptosis. ► Chlorpyrifos inhibits mitochondrial complex I activity. ► ROS is involved in chlorpyrifos-induced apoptosis. ► Chlorpyrifos affects cellular antioxidant systems. ► Chlorpyrifos-induced apoptosis mediates activation of MAPK.

  2. Reactive oxygen species regulated mitochondria-mediated apoptosis in PC12 cells exposed to chlorpyrifos

    International Nuclear Information System (INIS)

    Lee, Jeong Eun; Park, Jae Hyeon; Shin, In Chul; Koh, Hyun Chul

    2012-01-01

    Reactive oxidative species (ROS) generated by environmental toxicants including pesticides could be one of the factors underlying the neuronal cell damage in neurodegenerative diseases. In this study we found that chlorpyrifos (CPF) induced apoptosis in dopaminergic neuronal components of PC12 cells as demonstrated by the activation of caspases and nuclear condensation. Furthermore, CPF also reduced the tyrosine hydroxylase-positive immunoreactivity in substantia nigra of the rat. In addition, CPF induced inhibition of mitochondrial complex I activity. Importantly, N-acetyl cysteine (NAC) treatment effectively blocked apoptosis via the caspase-9 and caspase-3 pathways while NAC attenuated the inhibition of mitochondrial complex I activity as well as the oxidative metabolism of dopamine (DA). These results demonstrated that CPF-induced apoptosis was involved in mitochondrial dysfunction through the production of ROS. In the response of cellular antioxidant systems to CPF, we found that CPF treatment increased HO-1 expression while the expression of CuZnSOD and MnSOD was reduced. In addition, we found that CPF treatment activated MAPK pathways, including ERK 1/2, the JNK, and the p38 MAP kinase in a time-dependent manner. NAC treatment abolished MAPK phosphorylation caused by CPF, indicating that ROS are upstream signals of MAPK. Interestingly, MAPK inhibitors abolished cytotoxicity and reduced ROS generation by CPF treatment. Our results demonstrate that CPF induced neuronal cell death in part through MAPK activation via ROS generation, suggesting its potential to generate oxidative stress via mitochondrial damage and its involvement in oxidative stress-related neurodegenerative disease. -- Highlights: ► Chlorpyrifos induces apoptosis. ► Chlorpyrifos inhibits mitochondrial complex I activity. ► ROS is involved in chlorpyrifos-induced apoptosis. ► Chlorpyrifos affects cellular antioxidant systems. ► Chlorpyrifos-induced apoptosis mediates activation of MAPK.

  3. Emerging roles of hypoxia-inducible factors and reactive oxygen species in cancer and pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Shigeo Saito

    2015-06-01

    Full Text Available Eukaryotic organisms require oxygen homeostasis to maintain proper cellular function for survival. During conditions of low oxygen tension (hypoxia, cells activate the transcription of genes that induce an adaptive response, which supplies oxygen to tissues. Hypoxia and hypoxia-inducible factors (HIFs may contribute to the maintenance of putative cancer stem cells, which can continue self-renewal indefinitely and express stemness genes in hypoxic stress environments (stem cell niches. Reactive oxygen species (ROS have long been recognized as toxic by-products of aerobic metabolism that are harmful to living cells, leading to DNA damage, senescence, or cell death. HIFs may promote a cancer stem cell state, whereas the loss of HIFs induces the production of cellular ROS and activation of proteins p53 and p16Ink4a, which lead to tumor cell death and senescence. ROS seem to inhibit HIF regulation in cancer cells. By contrast, controversial data have suggested that hypoxia increases the generation of ROS, which prevents hydroxylation of HIF proteins by inducing their transcription as negative feedback. Moreover, hypoxic conditions enhance the generation of induced pluripotent stem cells (iPSCs. During reprogramming of somatic cells into a PSC state, cells attain a metabolic state typically observed in embryonic stem cells (ESCs. ESCs and iPSCs share similar bioenergetic metabolisms, including decreased mitochondrial number and activity, and induced anaerobic glycolysis. This review discusses the current knowledge regarding the emerging roles of ROS homeostasis in cellular reprogramming and the implications of hypoxic regulation in cancer development.

  4. High level of oxygen treatment causes cardiotoxicity with arrhythmias and redox modulation

    Energy Technology Data Exchange (ETDEWEB)

    Chapalamadugu, Kalyan C.; Panguluri, Siva K. [Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL (United States); Bennett, Eric S. [Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL (United States); Kolliputi, Narasaiah [Division of Allergy and Immunology, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL (United States); Tipparaju, Srinivas M., E-mail: stippara@health.usf.edu [Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL (United States)

    2015-01-01

    Hyperoxia exposure in mice leads to cardiac hypertrophy and voltage-gated potassium (Kv) channel remodeling. Because redox balance of pyridine nucleotides affects Kv function and hyperoxia alters cellular redox potential, we hypothesized that hyperoxia exposure leads to cardiac ion channel disturbances and redox changes resulting in arrhythmias. In the present study, we investigated the electrical changes and redox abnormalities caused by 72 h hyperoxia treatment in mice. Cardiac repolarization changes were assessed by acquiring electrocardiogram (ECG) and cardiac action potentials (AP). Biochemical assays were employed to identify the pyridine nucleotide changes, Kv1.5 expression and myocardial injury. Hyperoxia treatment caused marked bradycardia, arrhythmia and significantly prolonged (ms) the, RR (186.2 ± 10.7 vs. 146.4 ± 6.2), PR (46.8 ± 3.1 vs. 39.3 ± 1.6), QRS (10.8 ± 0.6 vs. 8.5 ± 0.2), QTc (57.1 ± 3.5 vs. 40 ± 1.4) and JT (13.4 ± 2.1 vs. 7.0 ± 0.5) intervals, when compared with normoxia group. Hyperoxia treatment also induced significant increase in cardiac action potential duration (APD) (ex-APD{sub 90}; 73.8 ± 9.5 vs. 50.9 ± 3.1 ms) and elevated levels of serum markers of myocardial injury; cardiac troponin I (TnI) and lactate dehydrogenase (LDH). Hyperoxia exposure altered cardiac levels of mRNA/protein expression of; Kv1.5, Kvβ subunits and SiRT1, and increased ratios of reduced pyridine nucleotides (NADH/NAD and NADPH/NADP). Inhibition of SiRT1 in H9C2 cells using Splitomicin resulted in decreased SiRT1 and Kv1.5 expression, suggesting that SiRT1 may mediate Kv1.5 downregulation. In conclusion, the cardiotoxic effects of hyperoxia exposure involve ion channel disturbances and redox changes resulting in arrhythmias. - Highlights: • Hyperoxia treatment leads to arrhythmia with prolonged QTc and action potential duration. • Hyperoxia treatment alters cardiac pyridine nucleotide [NAD(P)H/NAD(P)] levels. • SiRT1 and Kv1.5 are co

  5. High level of oxygen treatment causes cardiotoxicity with arrhythmias and redox modulation

    International Nuclear Information System (INIS)

    Chapalamadugu, Kalyan C.; Panguluri, Siva K.; Bennett, Eric S.; Kolliputi, Narasaiah; Tipparaju, Srinivas M.

    2015-01-01

    Hyperoxia exposure in mice leads to cardiac hypertrophy and voltage-gated potassium (Kv) channel remodeling. Because redox balance of pyridine nucleotides affects Kv function and hyperoxia alters cellular redox potential, we hypothesized that hyperoxia exposure leads to cardiac ion channel disturbances and redox changes resulting in arrhythmias. In the presen