Estrogen-induced DNA synthesis in vascular endothelial cells is mediated by ROS signaling

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Felty Quentin

2006-04-01

to be dose dependent. Conclusion We have shown that estrogen exposure stimulates the rapid production of intracellular ROS and they are involved in growth signaling of endothelial cells. It appears that the early estrogen signaling does not require estrogen receptor genomic signaling because we can inhibit estrogen-induced DNA synthesis by antioxidants. Findings of this study may further expand research defining the underlying mechanism of how estrogen may promote vascular lesions. It also provides important information for the design of new antioxidant-based drugs or new antioxidant gene therapy to protect the cardiovascular health of individuals sensitive to estrogen.

Oridonin stabilizes retinoic acid receptor alpha through ROS-activated NF-κB signaling.

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Cao, Yang; Wei, Wei; Zhang, Nan; Yu, Qing; Xu, Wen-Bin; Yu, Wen-Jun; Chen, Guo-Qiang; Wu, Ying-Li; Yan, Hua

2015-04-10

Retinoic acid receptor alpha (RARα) plays an essential role in the regulation of many biological processes, such as hematopoietic cell differentiation, while abnormal RARα function contributes to the pathogenesis of certain diseases including cancers, especially acute promyelocytic leukemia (APL). Recently, oridonin, a natural diterpenoid isolated from Rabdosia rubescens, was demonstrated to regulate RARα by increasing its protein level. However, the underlying molecular mechanism for this action has not been fully elucidated. In the APL cell line, NB4, the effect of oridonin on RARα protein was analyzed by western blot and real-time quantitative RT-PCR analyses. Flow cytometry was performed to detect intracellular levels of reactive oxygen species (ROS). The association between nuclear factor-kappa B (NF-κB) signaling and the effect of oridonin was assessed using specific inhibitors, shRNA gene knockdown, and immunofluorescence assays. In addition, primary leukemia cells were treated with oridonin and analyzed by western blot in this study. RARα possesses transcriptional activity in the presence of its ligand, all-trans retinoic acid (ATRA). Oridonin remarkably stabilized the RARα protein, which retained transcriptional activity. Oridonin also moderately increased intracellular ROS levels, while pretreatment with the ROS scavenger, N-acetyl-l-cysteine (NAC), dramatically abrogated RARα stabilization by oridonin. More intriguingly, direct exposure to low concentrations of H2O2 also increased RARα protein but not mRNA levels, suggesting a role for ROS in oridonin stabilization of RARα protein. Further investigations showed that NAC antagonized oridonin-induced activation of NF-κB signaling, while the NF-κB signaling inhibitor, Bay 11-7082, effectively blocked the oridonin increase in RARα protein levels. In line with this, over-expression of IκΒα (A32/36), a super-repressor form of IκΒα, or NF-κB-p65 knockdown inhibited oridonin or H2O2-induced

ROS signaling, oxidative stress and Nrf2 in pancreatic beta-cell function

International Nuclear Information System (INIS)

Pi Jingbo; Zhang Qiang; Fu Jingqi; Woods, Courtney G.; Hou Yongyong; Corkey, Barbara E.; Collins, Sheila; Andersen, Melvin E.

2010-01-01

This review focuses on the emerging evidence that reactive oxygen species (ROS) derived from glucose metabolism, such as H 2 O 2 , act as metabolic signaling molecules for glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells. Particular emphasis is placed on the potential inhibitory role of endogenous antioxidants, which rise in response to oxidative stress, in glucose-triggered ROS and GSIS. We propose that cellular adaptive response to oxidative stress challenge, such as nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant induction, plays paradoxical roles in pancreatic beta-cell function. On the one hand, induction of antioxidant enzymes protects beta-cells from oxidative damage and possible cell death, thus minimizing oxidative damage-related impairment of insulin secretion. On the other hand, the induction of antioxidant enzymes by Nrf2 activation blunts glucose-triggered ROS signaling, thus resulting in reduced GSIS. These two premises are potentially relevant to impairment of beta-cells occurring in the late and early stage of Type 2 diabetes, respectively. In addition, we summarized our recent findings that persistent oxidative stress due to absence of uncoupling protein 2 activates cellular adaptive response which is associated with impaired pancreatic beta-cell function.

Silver Nanoparticles Induce HePG-2 Cells Apoptosis Through ROS-Mediated Signaling Pathways

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Zhu, Bing; Li, Yinghua; Lin, Zhengfang; Zhao, Mingqi; Xu, Tiantian; Wang, Changbing; Deng, Ning

2016-04-01

Recently, silver nanoparticles (AgNPs) have been shown to provide a novel approach to overcome tumors, especially those of hepatocarcinoma. However, the anticancer mechanism of silver nanoparticles is unclear. Thus, the purpose of this study was to estimate the effect of AgNPs on proliferation and activation of ROS-mediated signaling pathway on human hepatocellular carcinoma HePG-2 cells. A simple chemical method for preparing AgNPs with superior anticancer activity has been showed in this study. AgNPs were detected by transmission electronic microscopy (TEM) and energy dispersive X-ray (EDX). The size distribution and zeta potential of silver nanoparticles were detected by Zetasizer Nano. The average size of AgNPs (2 nm) observably increased the cellular uptake by endocytosis. AgNPs markedly inhibited the proliferation of HePG-2 cells through induction of apoptosis with caspase-3 activation and PARP cleavage. AgNPs with dose-dependent manner significantly increased the apoptotic cell population (sub-G1). Furthermore, AgNP-induced apoptosis was found dependent on the overproduction of reactive oxygen species (ROS) and affecting of MAPKs and AKT signaling and DNA damage-mediated p53 phosphorylation to advance HePG-2 cells apoptosis. Therefore, our results show that the mechanism of ROS-mediated signaling pathways may provide useful information in AgNP-induced HePG-2 cell apoptosis.

Matrine pretreatment improves cardiac function in rats with diabetic cardiomyopathy via suppressing ROS/TLR-4 signaling pathway.

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Liu, Zhong-wei; Wang, Jun-kui; Qiu, Chuan; Guan, Gong-chang; Liu, Xin-hong; Li, Shang-jian; Deng, Zheng-rong

2015-03-01

Matrine is an alkaloid from Sophora alopecuroides L, which has shown a variety of pharmacological activities and potential therapeutic value in cardiovascular diseases. In this study we examined the protective effects of matrine against diabetic cardiomyopathy (DCM) in rats. Male SD rats were injected with streptozotocin (STZ) to induce DCM. One group of DCM rats was pretreated with matrine (200 mg·kg(-1)·d(-1), po) for 10 consecutive days before STZ injection. Left ventricular function was evaluated using invasive hemodynamic examination, and myocardiac apoptosis was assessed. Primary rat myocytes were used for in vitro experiments. Intracellular ROS generation, MDA content and GPx activity were determined. Real-time PCR and Western blotting were performed to detect the expression of relevant mRNAs and proteins. DCM rats exhibited abnormally elevated non-fasting blood glucose levels at 4 weeks after STZ injection, and LV function impairment at 16 weeks. The cardiac tissues of DCM rats showed markedly increased apoptosis, excessive ROS production, and activation of TLR-4/MyD-88/caspase-8/caspase-3 signaling. Pretreatment with matrine significantly decreased non-fasting blood glucose levels and improved LV function in DCM rats, which were associated with reducing apoptosis and ROS production, and suppressing TLR-4/MyD-88/caspase-8/caspase-3 signaling in cardiac tissues. Incubation in a high-glucose medium induced oxidative stress and activation of TLR-4/MyD-88 signaling in cultured myocytes in vitro, which were significantly attenuated by pretreatment with N-acetylcysteine. Excessive ROS production in DCM activates the TLR-4/MyD-88 signaling, resulting in cardiomyocyte apoptosis, whereas pretreatment with matrine improves cardiac function via suppressing ROS/TLR-4 signaling pathway.

Reward acts as a signal to control delay-period activity in delayed-response tasks.

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Ichihara-Takeda, Satoe; Takeda, Kazuyoshi; Funahashi, Shintaro

2010-03-31

Prefrontal delay-period activity represents a neural mechanism for the active maintenance of information and needs to be controlled by some signal to appropriately operate working memory. To examine whether reward-delivery acts as this signal, the effects of delay-period activity in response to unexpected reward-delivery were examined by analyzing single-neuron activity recorded in the primate dorsolateral prefrontal cortex. Among neurons that showed delay-period activity, 34% showed inhibition of this activity in response to unexpected reward-delivery. The delay-period activity of these neurons was affected by the expectation of reward-delivery. The strength of the reward signal in controlling the delay-period activity is related to the strength of the effect of reward information on the delay-period activity. These results indicate that reward-delivery acts as a signal to control delay-period activity.

Reactive oxygen species (ROS) and the heat stress response of Daphnia pulex: ROS-mediated activation of hypoxia-inducible factor 1 (HIF-1) and heat shock factor 1 (HSF-1) and the clustered expression of stress genes.

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Klumpen, Eva; Hoffschröer, Nadine; Zeis, Bettina; Gigengack, Ulrike; Dohmen, Elias; Paul, Rüdiger J

2017-01-01

Heat stress in ectotherms involves direct (e.g. protein damage) and/or indirect effects (temperature-induced hypoxia and ROS formation), which cause activation of the transcription factors (TF) heat shock factor 1 (HSF-1) and/or hypoxia-inducible factor 1 (HIF-1). The present study focused on the links between stress (ROS) signals, nuclear (n) and cytoplasmic (c) HSF-1/HIF-1 levels, and stress gene expression on mRNA and protein levels (e.g. heat-shock protein 90, HSP90) upon acute heat and ROS (H 2 O 2 ) stress. Acute heat stress (30°C) evoked fluctuations in ROS level. Different feeding regimens, which affected the glutathione (GSH) level, allowed altering the frequency of ROS fluctuations. Other data showed fluctuation frequency to depend also on ROS production rate. The heat-induced slow or fast ROS fluctuations (at high or low GSH levels) evoked slow or fast fluctuations in the levels of nHIF-1α, nHSF-1 and gene products (mRNAs and protein), albeit after different time delays. Time delays to ROS fluctuations were, for example,shorter for nHIF-1α than for nHSF-1 fluctuations, and nHIF-1α fluctuations preceded and nHSF-1 fluctuations followed fluctuations in HSP90 mRNA level. Cytoplasmic TF levels either changed little (cHIF-1α) or showed a steady increase (cHSF-1). Applying acute H 2 O 2 stress (at 20°C) revealed effects on nHIF-1α and mRNA levels, but no significant effects on nHSF-1 level. Transcriptome data additionally showed coordinated fluctuations of mRNA levels upon acute heat stress, involving mRNAs for HSPs and other stress proteins, with all corresponding genes carrying DNA binding motifs for HIF-1 and HSF-1. This study provided evidence for promoting effects of ROS and HIF-1 on early haemoglobin, HIF-1α and HSP90 mRNA expressions upon heat or ROS stress. The increasing cHSF-1 level likely affected nHSF-1 level and later HSP90 mRNA expression. Heat stress evoked ROS fluctuations, with this stress signal forwarded via nHIF-1 and nHSF-1

Skin Aging-Dependent Activation of the PI3K Signaling Pathway via Downregulation of PTEN Increases Intracellular ROS in Human Dermal Fibroblasts

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Eun-Mi Noh

2016-01-01

Full Text Available Reactive oxygen species (ROS play a major role in both chronological aging and photoaging. ROS induce skin aging through their damaging effect on cellular constituents. However, the origins of ROS have not been fully elucidated. We investigated that ROS generation of replicative senescent fibroblasts is generated by the modulation of phosphatidylinositol 3,4,5-triphosphate (PIP3 metabolism. Reduction of the PTEN protein, which dephosphorylates PIP3, was responsible for maintaining a high level of PIP3 in replicative cells and consequently mediated the activation of the phosphatidylinositol-3-OH kinase (PI3K/Akt pathway. Increased ROS production was blocked by inhibition of PI3K or protein kinase C (PKC or by NADPH oxidase activating in replicative senescent cells. These data indicate that the signal pathway to ROS generation in replicative aged skin cells can be stimulated by reduced PTEN level. Our results provide new insights into skin aging-associated modification of the PI3K/NADPH oxidase signaling pathway and its relationship with a skin aging-dependent increase of ROS in human dermal fibroblasts.

Spatio-temporal Model of Endogenous ROS and Raft-Dependent WNT/Beta-Catenin Signaling Driving Cell Fate Commitment in Human Neural Progenitor Cells

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Haack, Fiete; Lemcke, Heiko; Ewald, Roland; Rharass, Tareck; Uhrmacher, Adelinde M.

2015-01-01

Canonical WNT/β-catenin signaling is a central pathway in embryonic development, but it is also connected to a number of cancers and developmental disorders. Here we apply a combined in-vitro and in-silico approach to investigate the spatio-temporal regulation of WNT/β-catenin signaling during the early neural differentiation process of human neural progenitors cells (hNPCs), which form a new prospect for replacement therapies in the context of neurodegenerative diseases. Experimental measurements indicate a second signal mechanism, in addition to canonical WNT signaling, being involved in the regulation of nuclear β-catenin levels during the cell fate commitment phase of neural differentiation. We find that the biphasic activation of β-catenin signaling observed experimentally can only be explained through a model that combines Reactive Oxygen Species (ROS) and raft dependent WNT/β-catenin signaling. Accordingly after initiation of differentiation endogenous ROS activates DVL in a redox-dependent manner leading to a transient activation of down-stream β-catenin signaling, followed by continuous auto/paracrine WNT signaling, which crucially depends on lipid rafts. Our simulation studies further illustrate the elaborate spatio-temporal regulation of DVL, which, depending on its concentration and localization, may either act as direct inducer of the transient ROS/β-catenin signal or as amplifier during continuous auto-/parcrine WNT/β-catenin signaling. In addition we provide the first stochastic computational model of WNT/β-catenin signaling that combines membrane-related and intracellular processes, including lipid rafts/receptor dynamics as well as WNT- and ROS-dependent β-catenin activation. The model’s predictive ability is demonstrated under a wide range of varying conditions for in-vitro and in-silico reference data sets. Our in-silico approach is realized in a multi-level rule-based language, that facilitates the extension and modification of the

Targeting TRPM2 in ROS-Coupled Diseases

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Shinichiro Yamamoto

2016-09-01

Full Text Available Under pathological conditions such as inflammation and ischemia-reperfusion injury large amounts of reactive oxygen species (ROS are generated which, in return, contribute to the development and exacerbation of disease. The second member of the transient receptor potential (TRP melastatin subfamily, TRPM2, is a Ca2+-permeable non-selective cation channel, activated by ROS in an ADP-ribose mediated fashion. In other words, TRPM2 functions as a transducer that converts oxidative stress into Ca2+ signaling. There is good evidence that TRPM2 plays an important role in ROS-coupled diseases. For example, in monocytes the influx of Ca2+ through TRPM2 activated by ROS contributes to the aggravation of inflammation via chemokine production. In this review, the focus is on TRPM2 as a molecular linker between ROS and Ca2+ signaling in ROS-coupled diseases.

Targeting TRPM2 in ROS-Coupled Diseases.

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Yamamoto, Shinichiro; Shimizu, Shunichi

2016-09-07

Under pathological conditions such as inflammation and ischemia-reperfusion injury large amounts of reactive oxygen species (ROS) are generated which, in return, contribute to the development and exacerbation of disease. The second member of the transient receptor potential (TRP) melastatin subfamily, TRPM2, is a Ca(2+)-permeable non-selective cation channel, activated by ROS in an ADP-ribose mediated fashion. In other words, TRPM2 functions as a transducer that converts oxidative stress into Ca(2+) signaling. There is good evidence that TRPM2 plays an important role in ROS-coupled diseases. For example, in monocytes the influx of Ca(2+) through TRPM2 activated by ROS contributes to the aggravation of inflammation via chemokine production. In this review, the focus is on TRPM2 as a molecular linker between ROS and Ca(2+) signaling in ROS-coupled diseases.

Calcium and ROS: A mutual interplay

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Görlach, Agnes; Bertram, Katharina; Hudecova, Sona; Krizanova, Olga

2015-01-01

Calcium is an important second messenger involved in intra- and extracellular signaling cascades and plays an essential role in cell life and death decisions. The Ca2+ signaling network works in many different ways to regulate cellular processes that function over a wide dynamic range due to the action of buffers, pumps and exchangers on the plasma membrane as well as in internal stores. Calcium signaling pathways interact with other cellular signaling systems such as reactive oxygen species (ROS). Although initially considered to be potentially detrimental byproducts of aerobic metabolism, it is now clear that ROS generated in sub-toxic levels by different intracellular systems act as signaling molecules involved in various cellular processes including growth and cell death. Increasing evidence suggests a mutual interplay between calcium and ROS signaling systems which seems to have important implications for fine tuning cellular signaling networks. However, dysfunction in either of the systems might affect the other system thus potentiating harmful effects which might contribute to the pathogenesis of various disorders. PMID:26296072

Diapause formation and downregulation of insulin-like signaling via DAF-16/FOXO delays axonal degeneration and neuronal loss.

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Andrea Calixto

Full Text Available Axonal degeneration is a key event in the pathogenesis of neurodegenerative conditions. We show here that mec-4d triggered axonal degeneration of Caenorhabditis elegans neurons and mammalian axons share mechanistical similarities, as both are rescued by inhibition of calcium increase, mitochondrial dysfunction, and NMNAT overexpression. We then explore whether reactive oxygen species (ROS participate in axonal degeneration and neuronal demise. C. elegans dauers have enhanced anti-ROS systems, and dauer mec-4d worms are completely protected from axonal degeneration and neuronal loss. Mechanistically, downregulation of the Insulin/IGF-1-like signaling (IIS pathway protects neurons from degenerating in a DAF-16/FOXO-dependent manner and is related to superoxide dismutase and catalase-increased expression. Caloric restriction and systemic antioxidant treatment, which decrease oxidative damage, protect C. elegans axons from mec-4d-mediated degeneration and delay Wallerian degeneration in mice. In summary, we show that the IIS pathway is essential in maintaining neuronal homeostasis under pro-degenerative stimuli and identify ROS as a key intermediate of neuronal degeneration in vivo. Since axonal degeneration represents an early pathological event in neurodegeneration, our work identifies potential targets for therapeutic intervention in several conditions characterized by axonal loss and functional impairment.

Oxygen Consumption and Usage During Physical Exercise: The Balance Between Oxidative Stress and ROS-Dependent Adaptive Signaling

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Zhao, Zhongfu; Koltai, Erika; Ohno, Hideki; Atalay, Mustafa

2013-01-01

Abstract The complexity of human DNA has been affected by aerobic metabolism, including endurance exercise and oxygen toxicity. Aerobic endurance exercise could play an important role in the evolution of Homo sapiens, and oxygen was not important just for survival, but it was crucial to redox-mediated adaptation. The metabolic challenge during physical exercise results in an elevated generation of reactive oxygen species (ROS) that are important modulators of muscle contraction, antioxidant protection, and oxidative damage repair, which at moderate levels generate physiological responses. Several factors of mitochondrial biogenesis, such as peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), mitogen-activated protein kinase, and SIRT1, are modulated by exercise-associated changes in the redox milieu. PGC-1α activation could result in decreased oxidative challenge, either by upregulation of antioxidant enzymes and/or by an increased number of mitochondria that allows lower levels of respiratory activity for the same degree of ATP generation. Endogenous thiol antioxidants glutathione and thioredoxin are modulated with high oxygen consumption and ROS generation during physical exercise, controlling cellular function through redox-sensitive signaling and protein–protein interactions. Endurance exercise-related angiogenesis, up to a significant degree, is regulated by ROS-mediated activation of hypoxia-inducible factor 1α. Moreover, the exercise-associated ROS production could be important to DNA methylation and post-translation modifications of histone residues, which create heritable adaptive conditions based on epigenetic features of chromosomes. Accumulating data indicate that exercise with moderate intensity has systemic and complex health-promoting effects, which undoubtedly involve regulation of redox homeostasis and signaling. Antioxid. Redox Signal. 18, 1208–1246. PMID:22978553

Effects of Ursodeoxycholic Acid and Insulin on Palmitate-Induced ROS Production and Down-Regulation of PI3K/Akt Signaling Activity.

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Yokoyama, Kunihiro; Tatsumi, Yasuaki; Hayashi, Kazuhiko; Goto, Hidemi; Ishikawa, Tetsuya; Wakusawa, Shinya

2017-01-01

In obese and diabetic patients, plasma free fatty acid (FFA) levels are often elevated and may play a causal role in insulin resistance and reactive oxygen species (ROS) production. We have previously shown that ursodeoxycholic acid (UDCA) has antioxidative activity through the phosphatidylinositol 3-kinase (PI3K)/Akt signaling-mediated glutathione production. In this study, we investigated the effects of UDCA on insulin response by analyzing intracellular ROS and the activation of the PI3K/Akt signaling pathway in HepG2 cells treated with palmitate. The level of ROS was quantified using 2',7'-dichlorodihydrofluorescein diacetate (H 2 DCFDA), and the activation of the PI3K/Akt signaling pathway was determined by Western blotting assay using appropriate antibodies. The intracellular ROS levels were increased by palmitate but were reduced by treatment with UDCA and insulin. Furthermore, insulin significantly stimulated the phosphorylation of Akt. When the cells were pre-treated with palmitate, insulin-induced Akt-phosphorylation was markedly inhibited. However, when the cells were treated with palmitate and UDCA, the effects of insulin were partially restored. UDCA may have protective effects against palmitate-induced decreases in responsiveness to insulin.

Activation of AMPA receptor promotes TNF-α release via the ROS-cSrc-NFκB signaling cascade in RAW264.7 macrophages

Energy Technology Data Exchange (ETDEWEB)

Cheng, Xiu-Li [Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing (China); Ding, Fan [Office of Scientific R& D, Tsinghua University, Beijing (China); Li, Hui; Tan, Xiao-Qiu [Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing (China); Liu, Xiao [Department of Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing (China); Cao, Ji-Min, E-mail: caojimin@126.com [Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing (China); Gao, Xue, E-mail: longlongnose@163.com [Department of Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing (China)

2015-05-29

The relationship between glutamate signaling and inflammation has not been well defined. This study aimed to investigate the role of AMPA receptor (AMPAR) in the expression and release of tumor necrosis factor-alpha (TNF-α) from macrophages and the underlying mechanisms. A series of approaches, including confocal microscopy, immunofluorescency, flow cytometry, ELISA and Western blotting, were used to estimate the expression of AMPAR and downstream signaling molecules, TNF-α release and reactive oxygen species (ROS) generation in the macrophage-like RAW264.7 cells. The results demonstrated that AMPAR was expressed in RAW264.7 cells. AMPA significantly enhanced TNF-α release from RAW264.7 cells, and this effect was abolished by CNQX (AMPAR antagonist). AMPA also induced elevation of ROS production, phosphorylation of c-Src and activation of nuclear factor (NF)-κB in RAW264.7 cells. Blocking c-Src by PP2, scavenging ROS by glutathione (GSH) or inhibiting NF-κB activation by pyrrolidine dithiocarbamate (PDTC) decreased TNF-α production from RAW264.7 cells. We concluded that AMPA promotes TNF-α release in RAW264.7 macrophages likely through the following signaling cascade: AMPAR activation → ROS generation → c-Src phosphorylation → NF-κB activation → TNF-α elevation. The study suggests that AMPAR may participate in macrophage activation and inflammation. - Highlights: • AMPAR is expressed in RAW264.7 macrophages and is upregulated by AMPA stimulation. • Activation of AMPAR stimulates TNF-α release in macrophages through the ROS-cSrc-NFκB signaling cascade. • Macrophage AMPAR signaling may play an important role in inflammation.

Signal Propagation Delay as a Barrier to Control Applications in WAN

DEFF Research Database (Denmark)

Knudsen, Thomas Phillip; Patel, A.; Pedersen, Jens Myrup

With the advent in WAN of delay sensitive technical applications, such as remote control, signal propagation delay becomes a major problem. The extent of the problem is analysed by lower bounding the delay in relation to different transmission media. Requirements for reliability and bandwidth are...... are considered. The consequences of this bounding for communication network planning and provisioning are discussed in relation to mitigating the effects of signal propagation delay as a barrier to the penetration of control applications into WAN......With the advent in WAN of delay sensitive technical applications, such as remote control, signal propagation delay becomes a major problem. The extent of the problem is analysed by lower bounding the delay in relation to different transmission media. Requirements for reliability and bandwidth...

N-acetylcysteine attenuates hexavalent chromium-induced hypersensitivity through inhibition of cell death, ROS-related signaling and cytokine expression.

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Yu-Hsuan Lee

Full Text Available Chromium hypersensitivity (chromium-induced allergic contact dermatitis is an important issue in occupational skin disease. Hexavalent chromium (Cr (VI can activate the Akt, Nuclear factor κB (NF-κB, and Mitogen-activated protein kinase (MAPK pathways and induce cell death, via the effects of reactive oxygen species (ROS. Recently, cell death stimuli have been proposed to regulate the release of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α and interleukin-1 (IL-1. However, the exact effects of ROS on the signaling molecules and cytotoxicity involved in Cr(VI-induced hypersensitivity have not yet been fully demonstrated. N-acetylcysteine (NAC could increase glutathione levels in the skin and act as an antioxidant. In this study, we investigated the effects of NAC on attenuating the Cr(VI-triggered ROS signaling in both normal keratinocyte cells (HaCaT cells and a guinea pig (GP model. The results showed the induction of apoptosis, autophagy and ROS were observed after different concentrations of Cr(VI treatment. HaCaT cells pretreated with NAC exhibited a decrease in apoptosis and autophagy, which could affect cell viability. In addition, Cr (VI activated the Akt, NF-κB and MAPK pathways thereby increasing IL-1α and TNF-α production. However, all of these stimulation phenomena could be inhibited by NAC in both of in vitro and in vivo studies. These novel findings indicate that NAC may prevent the development of chromium hypersensitivity by inhibiting of ROS-induced cell death and cytokine expression.

Benzoquinone activates the ERK/MAPK signaling pathway via ROS production in HL-60 cells

International Nuclear Information System (INIS)

Ruiz-Ramos, Ruben; Cebrian, Mariano E.; Garrido, Efrain

2005-01-01

Benzene (BZ) is a class I carcinogen and its oxidation to reactive intermediates is a prerequisite of hematoxicity and myelotoxicity. The generated metabolites include hydroquinone, which is further oxidized to the highly reactive 1,4-benzoquinone (BQ) in bone marrow. Therefore, we explored the mechanisms underlying BQ-induced HL-60 cell proliferation by studying the role of BQ-induced reactive oxygen species (ROS) in the activation of the ERK-MAPK signaling pathway. BQ treatment (0.01-30 μM) showed that doses below 10 μM did not significantly reduce viability. ROS production after 3 μM BQ treatment increased threefold; however, catalase addition reduced ROS generation to basal levels. FACS analysis showed that BQ induced a fivefold increase in the proportion of cells in S-phase. We also observed a high proportion of Bromodeoxyuridine (BrdU) stained cells, indicating a higher DNA synthesis rate. BQ also produced rapid and prolonged phosphorylation of ERK1/2 proteins. Simultaneous treatment with catalase or PD98059, a potent MEK protein inhibitor, reduced cell recruitment into the S-phase and also abolished the ERK1/2 protein phosphorylation induced by BQ, suggesting that MEK/ERK is an important pathway involved in BQ-induced ROS mediated proliferation. The prolonged activation of ERK1/2 contributes to explain the increased S-phase cell recruitment and to understand the leukemogenic processes associated with exposure to benzene metabolites. Thus, the possible mechanism by which BQ induce HL-60 cells to enter the cell cycle and proliferate is linked to ROS production and its growth promoting effects by specific activation of regulating genes known to be activated by redox mechanisms

Iron overload promotes erythroid apoptosis through regulating HIF-1a/ROS signaling pathway in patients with myelodysplastic syndrome.

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Zheng, Qing-Qing; Zhao, You-Shan; Guo, Juan; Zhao, Si-da; Song, Lu-Xi; Fei, Cheng-Ming; Zhang, Zheng; Li, Xiao; Chang, Chun-Kang

2017-07-01

Erythroid apoptosis increases significantly in myelodysplastic syndrome (MDS) patients with iron overload, but the underlying mechanism is not fully clear. In this study, we aim to explore the effect of HIF-1a/ROS on erythroid apoptosis in MDS patients with iron overload. We found that iron overload injured cellular functions through up-regulating ROS levels in MDS/AML cells, including inhibited cell viability, increased cell apoptosis and blocked cell cycle at G0/G1 phase. Interestingly, overexpression of hypoxia inducible factor-1a (HIF-1a), which was under-expressed in iron overload models, reduced ROS levels and attenuated cell damage caused by iron overload in MDS/AML cells. And gene knockdown of HIF-1a got the similar results as iron overload in MDS/AML cells. Furthermore, iron overload caused high erythroid apoptosis was closely related with ROS in MDS patients. Importantly, the HIF-1a protein levels of erythrocytes elevated obviously after incubation with desferrioxamine (DFO) from MDS patients with iron overload, accompanied by ROS levels inhibited and erythroid apoptosis reduced. Taken together, our findings determine that the HIF-1a/ROS signaling pathway plays a key role in promoting erythroid apoptosis in MDS patients with iron overload. Copyright © 2017 Elsevier Ltd. All rights reserved.

The role of mitochondrial ROS in the aging brain.

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Stefanatos, Rhoda; Sanz, Alberto

2018-03-01

The brain is the most complex human organ, consuming more energy than any other tissue in proportion to its size. It relies heavily on mitochondria to produce energy and is made up of mitotic and postmitotic cells that need to closely coordinate their metabolism to maintain essential bodily functions. During aging, damaged mitochondria that produce less ATP and more reactive oxygen species (ROS) accumulate. The current consensus is that ROS cause oxidative stress, damaging mitochondria and resulting in an energetic crisis that triggers neurodegenerative diseases and accelerates aging. However, in model organisms, increasing mitochondrial ROS (mtROS) in the brain extends lifespan, suggesting that ROS may participate in signaling that protects the brain. Here, we summarize the mechanisms by which mtROS are produced at the molecular level, how different brain cells and regions produce different amounts of mtROS, and how mtROS levels change during aging. Finally, we critically discuss the possible roles of ROS in aging as signaling molecules and damaging agents, addressing whether age-associated increases in mtROS are a cause or a consequence of aging. © 2017 Federation of European Biochemical Societies.

Delay line MWPC hazard signals inspector

International Nuclear Information System (INIS)

Turner, D.B.; Kirsten, F.; Guiragossian, Z.G.T.; Schilling, R.

1976-01-01

The Hazard Inspector is a CAMAC module which divides a MWPC delay line into 8 independent signal monitor and control segments. Independent control effectively reduces delay line occupation time and cuts the number of background and non-trigger particles accepted by the 4XQT charge-time-pulse-width digitizer, a device presented in a separate communication. Only segments containing legitimate information are digitized. Non-trigger related events are gated out at the digitizer, and contaminating hits are noted for computer correction

The Effects of Aronia melanocarpa 'Viking' Extracts in Attenuating RANKL-Induced Osteoclastic Differentiation by Inhibiting ROS Generation and c-FOS/NFATc1 Signaling.

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Ghosh, Mithun; Kim, In Sook; Lee, Young Min; Hong, Seong Min; Lee, Taek Hwan; Lim, Ji Hong; Debnath, Trishna; Lim, Beong Ou

2018-03-08

This study aimed to determine the anti-osteoclastogenic effects of extracts from Aronia melanocarpa 'Viking' (AM) and identify the underlying mechanisms in vitro. Reactive oxygen species (ROS) are signal mediators in osteoclast differentiation. AM extracts inhibited ROS production in RAW 264.7 cells in a dose-dependent manner and exhibited strong radical scavenging activity. The extracts also attenuated the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts. To attain molecular insights, the effect of the extracts on the signaling pathways induced by receptor activator of nuclear factor kappa B ligand (RANKL) were also investigated. RANKL triggers many transcription factors through the activation of mitogen-activated protein kinase (MAPK) and ROS, leading to the induction of osteoclast-specific genes. The extracts significantly suppressed RANKL-induced activation of MAPKs, such as extracellular signal-regulated kinase (ERK), c-Jun- N -terminal kinase (JNK) and p38 and consequently led to the downregulation of c-Fos and nuclear factor of activated T cells 1 (NFATc1) protein expression which ultimately suppress the activation of the osteoclast-specific genes, cathepsin K, TRAP, calcitonin receptor and integrin β₃. In conclusion, our findings suggest that AM extracts inhibited RANKL-induced osteoclast differentiation by downregulating ROS generation and inactivating JNK/ERK/p38, nuclear factor kappa B (NF-κB)-mediated c-Fos and NFATc1 signaling pathway.

Microscopic Control Delay Modeling at Signalized Arterials Using Bluetooth Technology

OpenAIRE

Rajasekhar, Lakshmi

2011-01-01

Real-time control delay estimation is an important performance measure for any intersection to improve the signal timing plans dynamically in real-time and hence improve the overall system performance. Control delay estimates helps to determine the level-of-service (LOS) characteristics of various approaches at an intersection and takes into account deceleration delay, stopped delay and acceleration delay. All kinds of traffic delay calculation especially control delay calculation has always ...

Cadmium induces carcinogenesis in BEAS-2B cells through ROS-dependent activation of PI3K/AKT/GSK-3β/β-catenin signaling

Energy Technology Data Exchange (ETDEWEB)

Son, Young-Ok; Wang, Lei; Poyil, Pratheeshkumar; Budhraja, Amit; Hitron, J. Andrew; Zhang, Zhuo [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY (United States); Lee, Jeong-Chae [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY (United States); School of Dentistry and Institute of Oral Biosciences (BK21 program), Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Shi, Xianglin, E-mail: xshi5@email.uky.edu [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY (United States)

2012-10-15

Cadmium has been widely used in industry and is known to be carcinogenic to humans. Although it is widely accepted that chronic exposure to cadmium increases the incidence of cancer, the mechanisms underlying cadmium-induced carcinogenesis are unclear. The main aim of this study was to investigate the role of reactive oxygen species (ROS) in cadmium-induced carcinogenesis and the signal transduction pathways involved. Chronic exposure of human bronchial epithelial BEAS-2B cells to cadmium induced cell transformation, as evidenced by anchorage-independent growth in soft agar and clonogenic assays. Chronic cadmium treatment also increased the potential of these cells to invade and migrate. Injection of cadmium-stimulated cells into nude mice resulted in the formation of tumors. In contrast, the cadmium-mediated increases in colony formation, cell invasion and migration were prevented by transfection with catalase, superoxide dismutase-1 (SOD1), or SOD2. In particular, chronic cadmium exposure led to activation of signaling cascades involving PI3K, AKT, GSK-3β, and β-catenin and transfection with each of the above antioxidant enzymes markedly inhibited cadmium-mediated activation of these signaling proteins. Inhibitors specific for AKT or β-catenin almost completely suppressed the cadmium-mediated increase in total and active β-catenin proteins and colony formation. Moreover, there was a marked induction of AKT, GSK-3β, β-catenin, and carcinogenic markers in tumor tissues formed in mice after injection with cadmium-stimulated cells. Collectively, our findings suggest a direct involvement of ROS in cadmium-induced carcinogenesis and implicate a role of AKT/GSK-3β/β-catenin signaling in this process. -- Highlights: ► Chronic exposure to cadmium induces carcinogenic properties in BEAS-2B cells. ► ROS involved in cadmium-induced tumorigenicity of BEAS-2B cells. ► Cadmium activates ROS-dependent AKT/GSK-3β/β-catenin-mediated signaling. ► ROS

Curcumin Induced Human Gastric Cancer BGC-823 Cells Apoptosis by ROS-Mediated ASK1-MKK4-JNK Stress Signaling Pathway

Directory of Open Access Journals (Sweden)

Tao Liang

2014-09-01

Full Text Available The signaling mediated by stress-activated MAP kinases (MAPK, c-Jun N-terminal kinase (JNK has well-established importance in cancer. In the present report, we investigated the effects of curcumin on the signaling pathway in human gastric cancer BGC-823 cells. Curcumin induced reactive oxygen species (ROS production and BGC-823 cells apoptosis. Inhibition of ROS generation by antioxidant (NAC or Trion significantly prevented curcumin-mediated apoptosis. Notably, we observed that curcumin activated ASK1, a MAPKKK that is oxidative stress sensitive and responsible to phosphorylation of JNK via triggering cascades, up-regulated an upstream effector of the JNK, MKK4, and phosphorylated JNK protein expression in BGC-823 cells. However, curcumin induced ASK1-MKK4-JNK signaling was attenuated by NAC. All the findings confirm the possibility that oxidative stress-activated ASK1-MKK4-JNK signaling cascade promotes the apoptotic response in curcumin-treated BGC-823 cells.

Live longer on MARS: a yeast paradigm of mitochondrial adaptive ROS signaling in aging

Directory of Open Access Journals (Sweden)

Gerald S. Shadel

2014-04-01

Full Text Available Adaptive responses to stress, including hormesis, have been implicated in longevity, but their mechanisms and out comes are not fully understood. Here, I briefly summarize a longevity mechanism elucidated in the budding yeast chronological lifespan model by which Mitochondrial Adaptive ROS Signaling (MARS promotes beneficial epigenetic and metabolic remodeling. The potential relevance of MARS to the human disease Ataxia-Telangiectasia and as a potential anti-aging target is discussed.

ROS Hexapod

Science.gov (United States)

Davis, Kirsch; Bankieris, Derek

2016-01-01

As an intern project for NASA Johnson Space Center (JSC), my job was to familiarize myself and operate a Robotics Operating System (ROS). The project outcome converted existing software assets into ROS using nodes, enabling a robotic Hexapod to communicate to be functional and controlled by an existing PlayStation 3 (PS3) controller. Existing control algorithms and current libraries have no ROS capabilities within the Hexapod C++ source code when the internship started, but that has changed throughout my internship. Conversion of C++ codes to ROS enabled existing code to be compatible with ROS, and is now controlled using an existing PS3 controller. Furthermore, my job description was to design ROS messages and script programs that enabled assets to participate in the ROS ecosystem by subscribing and publishing messages. Software programming source code is written in directories using C++. Testing of software assets included compiling code within the Linux environment using a terminal. The terminal ran the code from a directory. Several problems occurred while compiling code and the code would not compile. So modifying code to where C++ can read the source code were made. Once the code was compiled and ran, the code was uploaded to Hexapod and then controlled by a PS3 controller. The project outcome has the Hexapod fully functional and compatible with ROS and operates using the PlayStation 3 controller. In addition, an open source software (IDE) Arduino board will be integrated into the ecosystem with designing circuitry on a breadboard to add additional behavior with push buttons, potentiometers and other simple elements in the electrical circuitry. Other projects with the Arduino will be a GPS module, digital clock that will run off 22 satellites to show accurate real time using a GPS signal and an internal patch antenna to communicate with satellites. In addition, this internship experience has led me to pursue myself to learn coding more efficiently and

Transcriptomic profiling of linolenic acid-responsive genes in ROS signalling from RNA-seq data in Arabidopsis

Directory of Open Access Journals (Sweden)

Capilla eMata-Pérez

2015-03-01

Full Text Available Linolenic acid (Ln released from chloroplast membrane galactolipids is a precursor of the phytohormone jasmonic acid (JA. The involvement of this hormone in different plant biological processes, such as responses to biotic stress conditions, has been extensively studied. However, the role of Ln in the regulation of gene expression during abiotic stress situations mediated by cellular redox changes and/or by oxidative stress processes remains poorly understood. An RNA-seq approach has increased our knowledge of the interplay among Ln, oxidative stress and ROS signalling that mediates abiotic stress conditions. Transcriptome analysis with the aid of RNA-seq in the absence of oxidative stress revealed that the incubation of Arabidopsis thaliana cell suspension cultures (ACSC with Ln resulted in the modulation of 7525 genes, of which 3034 genes had a 2 fold-change, being 533 up- and 2501 down-regulated genes, respectively. Thus, RNA-seq data analysis showed that an important set of these genes were associated with the jasmonic acid biosynthetic pathway including lypoxygenases (LOXs and Allene oxide cyclases (AOCs. In addition, several transcription factor families involved in the response to biotic stress conditions (pathogen attacks or herbivore feeding, such as WRKY, JAZ, MYC and LRR were also modified in response to Ln. However, this study also shows that Ln has the capacity to modulate the expression of genes involved in the response to abiotic stress conditions, particularly those mediated by ROS signalling. In this regard, we were able to identify new targets such as galactinol synthase 1 (GOLS1, methionine sulfoxide reductase (MSR and alkenal reductase in ACSC. It is therefore possible to suggest that, in the absence of any oxidative stress, Ln is capable of modulating new sets of genes involved in the signalling mechanism mediated by additional abiotic stresses (salinity, UV and high light intensity and especially in stresses mediated by ROS.

ROS and calcium signaling mediated pathways involved in stress responses of the marine microalgae Dunaliella salina to enhanced UV-B radiation.

Science.gov (United States)

Zhang, Xinxin; Tang, Xuexi; Wang, Ming; Zhang, Wei; Zhou, Bin; Wang, You

2017-08-01

UV-B ray has been addressed to trigger common metabolic responses on marine microalgae, however, the upstream events responsible for these changes in marine microalgae are poorly understood. In the present study, a species of marine green microalgae Dunaliella salina was exposed to a series of enhanced UV-B radiation ranging from 0.25 to 1.00 KJ·m -2 per day. The role of ROS and calcium signaling in the D. salina responses to UV-B was discussed. Results showed that enhanced UV-B radiation markedly decreased the cell density in a dose-dependent manner, but the contents of protein and glycerol that were essential for cell growth increased. It suggested that it was cell division instead of cell growth that UV-B exerted negative effects on. The subcellular damages on nuclei and plasmalemma further evidenced the hypothesis. The nutrient absorption was affected with UV-B exposure, and the inhibition on PO 4 3- uptake was more serious compared to NO 3 - uptake. UV-B radiation promoted reactive oxygen species (ROS) formation and thiobarbituric acid reactive substances (TBARS) contents, decreased the redox status and altered the antioxidant enzyme activities. The addition of the ROS scavenger and the glutathione biosynthesis precursor N-acetyl-l-cysteine (NAC) alleviated the stress degree, implying ROS-mediated pathway was involved in the stress response to UV-B radiation. Transient increase in Ca 2+ -ATPase was triggered simultaneously with UV-B exposure. Meanwhile, the addition of an intracellular free calcium chelator aggravated the damage of cell division, but exogenous calcium and ion channel blocker applications did not, inferring that endogenously initiated calcium signaling played roles in response to UV-B. Cross-talk analysis showed a relatively clear relationship between ROS inhibition and Ca 2+ -ATPase suppression, and a relation between Ca 2+ inhibition and GPx activity change was also observed. It was thus presumed that ROS-coupled calcium signaling via the

Nonlinear Estimation of Discrete-Time Signals Under Random Observation Delay

International Nuclear Information System (INIS)

Caballero-Aguila, R.; Jimenez-Lopez, J. D.; Hermoso-Carazo, A.; Linares-Perez, J.; Nakamori, S.

2008-01-01

This paper presents an approximation to the nonlinear least-squares estimation problem of discrete-time stochastic signals using nonlinear observations with additive white noise which can be randomly delayed by one sampling time. The observation delay is modelled by a sequence of independent Bernoulli random variables whose values, zero or one, indicate that the real observation arrives on time or it is delayed and, hence, the available measurement to estimate the signal is not up-to-date. Assuming that the state-space model generating the signal is unknown and only the covariance functions of the processes involved in the observation equation are ready for use, a filtering algorithm based on linear approximations of the real observations is proposed.

Ascorbic acid alters cell fate commitment of human neural progenitors in a WNT/β-catenin/ROS signaling dependent manner.

Science.gov (United States)

Rharass, Tareck; Lantow, Margareta; Gbankoto, Adam; Weiss, Dieter G; Panáková, Daniela; Lucas, Stéphanie

2017-10-16

Improving the neuronal yield from in vitro cultivated neural progenitor cells (NPCs) is an essential challenge in transplantation therapy in neurological disorders. In this regard, Ascorbic acid (AA) is widely used to expand neurogenesis from NPCs in cultures although the mechanisms of its action remain unclear. Neurogenesis from NPCs is regulated by the redox-sensitive WNT/β-catenin signaling pathway. We therefore aimed to investigate how AA interacts with this pathway and potentiates neurogenesis. Effects of 200 μM AA were compared with the pro-neurogenic reagent and WNT/β-catenin signaling agonist lithium chloride (LiCl), and molecules with antioxidant activities i.e. N-acetyl-L-cysteine (NAC) and ruthenium red (RuR), in differentiating neural progenitor ReNcell VM cells. Cells were supplemented with reagents for two periods of treatment: a full period encompassing the whole differentiation process versus an early short period that is restricted to the cell fate commitment stage. Intracellular redox balance and reactive oxygen species (ROS) metabolism were examined by flow cytometry using redox and ROS sensors. Confocal microscopy was performed to assess cell viability, neuronal yield, and levels of two proteins: Nucleoredoxin (NXN) and the WNT/β-catenin signaling component Dishevelled 2 (DVL2). TUBB3 and MYC gene responses were evaluated by quantitative real-time PCR. DVL2-NXN complex dissociation was measured by fluorescence resonance energy transfer (FRET). In contrast to NAC which predictably exhibited an antioxidant effect, AA treatment enhanced ROS metabolism with no cytotoxic induction. Both drugs altered ROS levels only at the early stage of the differentiation as no changes were held beyond the neuronal fate commitment stage. FRET studies showed that AA treatment accelerated the redox-dependent release of the initial pool of DVL2 from its sequestration by NXN, while RuR treatment hampered the dissociation of the two proteins. Accordingly, AA

Measurement System for Playout Delay of TV Signals

NARCIS (Netherlands)

Kooij, W.J.; Stokking, H.M.; Brandenburg, R. van; Boer, P.T. de

2014-01-01

TV signals are carried towards end-users using different (broadcast) technologies and by different providers. This is causing differences in the playout timing of the TV signal at different locations and devices. Authors have developed a measurement system for measuring the relative playout delay of

ROS are critical for endometrial breakdown via NF-κB-COX-2 signaling in a female mouse menstrual-like model.

Science.gov (United States)

Wu, Bin; Chen, Xihua; He, Bin; Liu, Shuyan; Li, Yunfeng; Wang, Qianxing; Gao, Haijun; Wang, Shufang; Liu, Jianbing; Zhang, Shucheng; Xu, Xiangbo; Wang, Jiedong

2014-09-01

Progesterone withdrawal triggers endometrial breakdown and shedding during menstruation. Menstruation results from inflammatory responses; however, the role of reactive oxygen species (ROS) in menstruation remains unclear. In this study, we explored the role of ROS in endometrial breakdown and shedding. We found that ROS levels were significantly increased before endometrial breakdown in a mouse menstrual-like model. Vaginal smear inspection, morphology of uterine horns, and endometrial histology examination showed that a broad range of ROS scavengers significantly inhibited endometrial breakdown in this model. Furthermore, Western blot and immunohistochemical analysis showed that the intracellular translocation of p50 and p65 from the cytoplasm into the nucleus was blocked by ROS scavengers and real-time PCR showed that cyclooxygenase-2 (COX-2) mRNA expression was decreased by ROS scavengers. Similar changes also occurred in human stromal cells in vitro. Furthermore, Western blotting and real-time PCR showed that one ROS, hydrogen peroxide (H2O2), promoted translocation of p50 and p65 from the cytoplasm to the nucleus and increased COX-2 mRNA expression along with progesterone maintenance. The nuclear factor κB inhibitor MG132 reduced the occurrence of these changes in human stromal cells in vitro. Viewed as a whole, our results provide evidence that certain ROS are important for endometrial breakdown and shedding in a mouse menstrual-like model and function at least partially via nuclear factor-κB/COX-2 signaling. Similar changes observed in human stromal cells could also implicate ROS as important mediators of human menstruation.

The Effects of Aronia melanocarpa ‘Viking’ Extracts in Attenuating RANKL-Induced Osteoclastic Differentiation by Inhibiting ROS Generation and c-FOS/NFATc1 Signaling

Directory of Open Access Journals (Sweden)

Mithun Ghosh

2018-03-01

Full Text Available This study aimed to determine the anti-osteoclastogenic effects of extracts from Aronia melanocarpa ‘Viking’ (AM and identify the underlying mechanisms in vitro. Reactive oxygen species (ROS are signal mediators in osteoclast differentiation. AM extracts inhibited ROS production in RAW 264.7 cells in a dose-dependent manner and exhibited strong radical scavenging activity. The extracts also attenuated the number of tartrate-resistant acid phosphatase (TRAP-positive multinucleated osteoclasts. To attain molecular insights, the effect of the extracts on the signaling pathways induced by receptor activator of nuclear factor kappa B ligand (RANKL were also investigated. RANKL triggers many transcription factors through the activation of mitogen-activated protein kinase (MAPK and ROS, leading to the induction of osteoclast-specific genes. The extracts significantly suppressed RANKL-induced activation of MAPKs, such as extracellular signal-regulated kinase (ERK, c-Jun-N-terminal kinase (JNK and p38 and consequently led to the downregulation of c-Fos and nuclear factor of activated T cells 1 (NFATc1 protein expression which ultimately suppress the activation of the osteoclast-specific genes, cathepsin K, TRAP, calcitonin receptor and integrin β3. In conclusion, our findings suggest that AM extracts inhibited RANKL-induced osteoclast differentiation by downregulating ROS generation and inactivating JNK/ERK/p38, nuclear factor kappa B (NF-κB-mediated c-Fos and NFATc1 signaling pathway.

Improved delayed signal cancellation-based SRF-PLL for unbalanced grid

DEFF Research Database (Denmark)

Messo, Tuomas; Sihvo, Jussi; Yang, Dongsheng

2017-01-01

Problems with power quality in the grid have gained a lot of attention recently due to rapid increase in the amount of grid-connected power converters. The converter should produce sinusoidal currents also during abnormal conditions, such as unbalanced grid voltages. Several methods, like...... the delayed signal cancellation-based method (DSC), have been proposed to alleviate the detrimental effect of unbalance. This paper proposes an improvement to a delayed signal cancellation based synchronization algorithm for unbalanced grids. The proposed PLL structure employs only half of the delay required...

TMEPAI regulates EMT in lung cancer cells by modulating the ROS and IRS-1 signaling pathways.

Science.gov (United States)

Hu, Ying; He, Kai; Wang, Dongmei; Yuan, Xinwang; Liu, Yi; Ji, Hongbin; Song, Jianguo

2013-08-01

The epithelial-mesenchymal transition (EMT) has been implicated in various pathophysiological processes, including cancer cell migration and distal metastasis. Reactive oxygen species (ROS) and insulin receptor substrate-1 (IRS-1) are important in cancer progression and regulation of EMT. To explore the biological significance and regulatory mechanism of EMT, we determined the expression, the biological function and the signaling pathway of prostate transmembrane protein, androgen induced-1 (TMEPAI), during the induction of EMT and cell migration. Transforming growth factor (TGF)-β1 significantly upregulated the expression of TMEPAI during EMT in human lung adenocarcinoma. Depletion of TMEPAI abolished TGF-β1-induced downregulation of ferritin heavy chain and the subsequent generation of ROS, thus suppressing TGF-β1-induced EMT and cell migration. In addition, increased ROS production and overexpression of TMEPAI downregulated the level of IRS-1. Both the addition of H2O2 and IRS-1 small interfering RNA rescued the ability of TGF-β1 to induce EMT in TMEPAI-depleted cells. Remarkably, the levels of TMEPAI in lung tumor tissues are very high, whereas its expression in normal lung epithelium is very low. Moreover, TMEPAI expression was positively correlated with the cell mesenchymal phenotype and migration potential. Our work reveals that TMEPAI contributes to TGF-β1-induced EMT through ROS production and IRS-1 downregulation in lung cancer cells.

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)

Recent advances in intracellular and in vivo ROS sensing: focus on nanoparticle and nanotube applications.

Science.gov (United States)

Uusitalo, Larissa M; Hempel, Nadine

2012-01-01

Reactive oxygen species (ROS) are increasingly being implicated in the regulation of cellular signaling cascades. Intracellular ROS fluxes are associated with cellular function ranging from proliferation to cell death. Moreover, the importance of subtle, spatio-temporal shifts in ROS during localized cellular signaling events is being realized. Understanding the biochemical nature of the ROS involved will enhance our knowledge of redox-signaling. An ideal intracellular sensor should therefore resolve real-time, localized ROS changes, be highly sensitive to physiologically relevant shifts in ROS and provide specificity towards a particular molecule. For in vivo applications issues such as bioavailability of the probe, tissue penetrance of the signal and signal-to-noise ratio also need to be considered. In the past researchers have heavily relied on the use of ROS-sensitive fluorescent probes and, more recently, genetically engineered ROS sensors. However, there is a great need to improve on current methods to address the above issues. Recently, the field of molecular sensing and imaging has begun to take advantage of the unique physico-chemical properties of nanoparticles and nanotubes. Here we discuss the recent advances in the use of these nanostructures as alternative platforms for ROS sensing, with particular emphasis on intracellular and in vivo ROS detection and quantification.

Joint Maximum Likelihood Time Delay Estimation of Unknown Event-Related Potential Signals for EEG Sensor Signal Quality Enhancement

Science.gov (United States)

Kim, Kyungsoo; Lim, Sung-Ho; Lee, Jaeseok; Kang, Won-Seok; Moon, Cheil; Choi, Ji-Woong

2016-01-01

Electroencephalograms (EEGs) measure a brain signal that contains abundant information about the human brain function and health. For this reason, recent clinical brain research and brain computer interface (BCI) studies use EEG signals in many applications. Due to the significant noise in EEG traces, signal processing to enhance the signal to noise power ratio (SNR) is necessary for EEG analysis, especially for non-invasive EEG. A typical method to improve the SNR is averaging many trials of event related potential (ERP) signal that represents a brain’s response to a particular stimulus or a task. The averaging, however, is very sensitive to variable delays. In this study, we propose two time delay estimation (TDE) schemes based on a joint maximum likelihood (ML) criterion to compensate the uncertain delays which may be different in each trial. We evaluate the performance for different types of signals such as random, deterministic, and real EEG signals. The results show that the proposed schemes provide better performance than other conventional schemes employing averaged signal as a reference, e.g., up to 4 dB gain at the expected delay error of 10°. PMID:27322267

Joint Maximum Likelihood Time Delay Estimation of Unknown Event-Related Potential Signals for EEG Sensor Signal Quality Enhancement

Directory of Open Access Journals (Sweden)

Kyungsoo Kim

2016-06-01

Full Text Available Electroencephalograms (EEGs measure a brain signal that contains abundant information about the human brain function and health. For this reason, recent clinical brain research and brain computer interface (BCI studies use EEG signals in many applications. Due to the significant noise in EEG traces, signal processing to enhance the signal to noise power ratio (SNR is necessary for EEG analysis, especially for non-invasive EEG. A typical method to improve the SNR is averaging many trials of event related potential (ERP signal that represents a brain’s response to a particular stimulus or a task. The averaging, however, is very sensitive to variable delays. In this study, we propose two time delay estimation (TDE schemes based on a joint maximum likelihood (ML criterion to compensate the uncertain delays which may be different in each trial. We evaluate the performance for different types of signals such as random, deterministic, and real EEG signals. The results show that the proposed schemes provide better performance than other conventional schemes employing averaged signal as a reference, e.g., up to 4 dB gain at the expected delay error of 10°.

Endoplasmic Reticulum Stress and Associated ROS

Directory of Open Access Journals (Sweden)

Hafiz Maher Ali Zeeshan

2016-03-01

Full Text Available The endoplasmic reticulum (ER is a fascinating network of tubules through which secretory and transmembrane proteins enter unfolded and exit as either folded or misfolded proteins, after which they are directed either toward other organelles or to degradation, respectively. The ER redox environment dictates the fate of entering proteins, and the level of redox signaling mediators modulates the level of reactive oxygen species (ROS. Accumulating evidence suggests the interrelation of ER stress and ROS with redox signaling mediators such as protein disulfide isomerase (PDI-endoplasmic reticulum oxidoreductin (ERO-1, glutathione (GSH/glutathione disuphide (GSSG, NADPH oxidase 4 (Nox4, NADPH-P450 reductase (NPR, and calcium. Here, we reviewed persistent ER stress and protein misfolding-initiated ROS cascades and their significant roles in the pathogenesis of multiple human disorders, including neurodegenerative diseases, diabetes mellitus, atherosclerosis, inflammation, ischemia, and kidney and liver diseases.

ROS and RNS in plant physiology: an overview.

Science.gov (United States)

Del Río, Luis A

2015-05-01

The production of reactive oxygen species (ROS) is the unavoidable consequence of aerobic life. ROS is a collective term that includes both oxygen radicals, like superoxide (O 2. -) and hydroxyl (·OH) radicals, and other non-radicals such as hydrogen peroxide (H2O2), singlet oxygen ((1)O2 or (1)Δg), etc. In plants, ROS are produced in different cell compartments and are oxidizing species, particularly hydroxyl radicals and singlet oxygen, that can produce serious damage in biological systems (oxidative stress). However, plant cells also have an array of antioxidants which, normally, can scavenge the excess oxidants produced and so avoid deleterious effects on the plant cell bio-molecules. The concept of 'oxidative stress' was re-evaluated in recent years and the term 'oxidative signalling' was created. This means that ROS production, apart from being a potentially harmful process, is also an important component of the signalling network that plants use for their development and for responding to environmental challenges. It is known that ROS play an important role regulating numerous biological processes such as growth, development, response to biotic and environmental stresses, and programmed cell death. The term reactive nitrogen species (RNS) includes radicals like nitric oxide (NO· ) and nitric dioxide (NO2.), as well as non-radicals such as nitrous acid (HNO2) and dinitrogen tetroxide (N2O4), among others. RNS are also produced in plants although the generating systems have still not been fully characterized. Nitric oxide (NO·) has an important function as a key signalling molecule in plant growth, development, and senescence, and RNS, like ROS, also play an important role as signalling molecules in the response to environmental (abiotic) stress. Similarly, NO· is a key mediator, in co-operation with ROS, in the defence response to pathogen attacks in plants. ROS and RNS have been demonstrated to have an increasingly important role in biology and medicine

Up-regulation of ROS by mitochondria-dependent bystander signaling contributes to genotoxicity of bystander effects

International Nuclear Information System (INIS)

Chen Shaopeng; Zhao Ye; Zhao Guoping; Han Wei; Bao Lingzhi; Yu, K.N.; Wu Lijun

2009-01-01

Genomic instability can be observed in bystander cells. However, the underlying mechanism(s) is still relatively unclear. In a previous study, we found that irradiated cells released mitochondria-dependent intracellular factor(s) which could lead to bystander γ-H2AX induction. In this paper, we used normal (ρ + ) and mtDNA-depleted (ρ 0 ) human-hamster hybrid cells to investigate mitochondrial effects on the genotoxicity in bystander effect through medium transfer experiments. Through the detection of DNA double-strand breaks with γ-H2AX, we found that the fraction of γ-H2AX positive cells changed with time when irradiation conditioned cell medium (ICCM) were harvested. ICCM harvested from irradiated ρ + cells at 10 min post-irradiation (ρ + ICCM 10min ) caused larger increases of bystander γ-H2AX induction comparing to ρ 0 ICCM 10min , which only caused a slight increase of bystander γ-H2AX induction. The ρ + ICCM 10min could also result in the up-regulation of ROS production (increased by 35% at 10 min), while there was no significant increase in cells treated with ρ 0 ICCM 10min . We treated cells with dimethyl sulfoxide (DMSO), the scavenger of ROS, and quenched γ-H2AX induction by ρ + ICCM. Furthermore, after the medium had been transferred and the cells were continuously cultured for 7 days, we found significantly increased CD59 - gene loci mutation (increased by 45.9%) and delayed cell death in the progeny of ρ + ICCM-treated bystander cells. In conclusion, the work presented here suggested that up-regulation of the mitochondria-dependent ROS might be very important in mediating genotoxicity of bystander effects.

Damaged-self recognition in common bean (Phaseolus vulgaris shows taxonomic specificity and triggers signalling via reactive oxygen species (ROS

Directory of Open Access Journals (Sweden)

Dalia eDuran

2014-10-01

Full Text Available Plants require reliable mechanisms to detect injury. Danger signals or 'damage-associated molecular patterns' (DAMPs are released from stressed host cells and allow injury detection independently of enemy-derived molecules. We studied the response of common bean (Phaseolus vulgaris to the application of leaf homogenate as a source of DAMPs and measured the production of reactive oxygen species (ROS as an early response and the secretion of extrafloral nectar (EFN as a jasmonic acid (JA–dependent late response. We observed a strong taxonomic signal in the response to different leaf homogenates. ROS formation and EFN secretion were highly correlated and responded most strongly to leaf homogenates produced using the same cultivar or closely related accessions, less to a distantly related cultivar of common bean or each of the two congeneric species, P. lunatus and P. coccineus, and not at all to homogenates prepared from species in different genera, not even when using other Fabaceae. Interestingly, leaf homogenates also reduced the infection by the bacterial pathogen, Pseudomonas syringae, when they were applied directly before challenging, although the same homogenates exhibited no direct in vitro inhibitory effect in the bacterium. We conclude that ROS signaling is associated to the induction of EFN secretion and that the specific blend of DAMPs that are released from damaged cells allows the plant to distinguish the 'damaged self' from the damaged 'non-self'. The very early responses of plants to DAMPs can trigger resistance to both, herbivores and pathogens, which should be adaptive because injury facilitates infection, independently of its causal reason.

Detection of ROS Induced Proteomic Signatures by Mass Spectrometry

Directory of Open Access Journals (Sweden)

Brian McDonagh

2017-07-01

Full Text Available Reversible and irreversible post-translational modifications (PTMs induced by endogenously generated reactive oxygen species (ROS in regulatory enzymes and proteins plays an essential role in cellular signaling. Almost all cellular processes including metabolism, transcription, translation and degradation have been identified as containing redox regulated proteins. Specific redox modifications of key amino acids generated by ROS offers a dynamic and versatile means to rapidly alter the activity or functional structure of proteins in response to biochemical, environmental, genetic and pathological perturbations. How the proteome responds to these stimuli is of critical importance in oxidant physiology, as it can regulate the cell stress response by reversible and irreversible PTMs, affecting protein activity and protein-protein interactions. Due to the highly labile nature of many ROS species, applying redox proteomics can provide a signature footprint of the ROS species generated. Ideally redox proteomic approaches would allow; (1 the identification of the specific PTM, (2 identification of the amino acid residue that is modified and (3 the percentage of the protein containing the PTM. New developments in MS offer the opportunity of a more sensitive targeted proteomic approach and retrospective data analysis. Subsequent bioinformatics analysis can provide an insight into the biochemical and physiological pathways or cell signaling cascades that are affected by ROS generation. This mini-review will detail current redox proteomic approaches to identify and quantify ROS induced PTMs and the subsequent effects on cellular signaling.

Robot operating system (ROS) the complete reference

CERN Document Server

The objective of this book is to provide the reader with a comprehensive coverage on the Robot Operating Systems (ROS) and latest related systems, which is currently considered as the main development framework for robotics applications. The book includes twenty-seven chapters organized into eight parts. Part 1 presents the basics and foundations of ROS. In Part 2, four chapters deal with navigation, motion and planning. Part 3 provides four examples of service and experimental robots. Part 4 deals with real-world deployment of applications. Part 5 presents signal-processing tools for perception and sensing. Part 6 provides software engineering methodologies to design complex software with ROS. Simulations frameworks are presented in Part 7. Finally, Part 8 presents advanced tools and frameworks for ROS including multi-master extension, network introspection, controllers and cognitive systems. This book will be a valuable companion for ROS users and developers to learn more ROS capabilities and features.   ...

Stochastic resonance in a time-delayed asymmetric bistable system with mixed periodic signal

International Nuclear Information System (INIS)

Yong-Feng, Guo; Wei, Xu; Liang, Wang

2010-01-01

This paper studies the phenomenon of stochastic resonance in an asymmetric bistable system with time-delayed feedback and mixed periodic signal by using the theory of signal-to-noise ratio in the adiabatic limit. A general approximate Fokker–Planck equation and the expression of the signal-to-noise ratio are derived through the small time delay approximation at both fundamental harmonics and mixed harmonics. The effects of the additive noise intensity Q, multiplicative noise intensity D, static asymmetry r and delay time τ on the signal-to-noise ratio are discussed. It is found that the higher mixed harmonics and the static asymmetry r can restrain stochastic resonance, and the delay time τ can enhance stochastic resonance. Moreover, the longer the delay time τ is, the larger the additive noise intensity Q and the multiplicative noise intensity D are, when the stochastic resonance appears. (general)

Estimating Angle of Arrival (AOA for Wideband Signal by Sensor Delay Line (SDL and Tapped Delay Line (TDL Processors

Directory of Open Access Journals (Sweden)

Bassim Sayed Mohammed

2018-04-01

Full Text Available Angle of arrival (AOA estimation for wideband signal becomes more necessary for modern communication systems like Global System for Mobile (GSM, satellite, military applications and spread spectrum (frequency hopping and direct sequence. Most of the researchers are focusing on how to cancel the effects of signal bandwidth on AOA estimation performance by using a transversal filter (tap delay line (TDL. Most of the researchers were using two elements array antenna to study these effects. In this research, a general case of proposed (M array elements is used. A transversal filter (TDL in phase adaptive array antenna system is used to calculate the optimum number of taps required to compensate these effect. The proposed system uses a phase adaptive array antenna in conjunction with LMS algorithm to work an angle of arrival (AOA estimator for wideband signals rather than interference canceller. An alternative solution to compensate for the effect of signal bandwidth is proposed by using sensor delay line (SDL instead of fixed delay unit since it has variable time sampling in the time domain and not fixed time delay, depending on the angle of arrival of received signals. The proposed system has the ability to estimate two parameters for received signals simultaneously (the output Signal to Noise Ratio (SNR and AOA, unlike others systems which estimate AOA only. The comparison of the simulation results with Multiple Signal Classification (MUSIC technique showed that the proposed system gives good results for estimating AOA and the output SNR for wideband signals. (SDL processor shows better performance result than (TDL processor. MUSIC technique with both (SDL and (TDL processors shows unacceptable results for estimating (AOA for the wideband signal.

Whistler-mode signals: Group delay by cross correlation

International Nuclear Information System (INIS)

Thomson, N.R.

1975-01-01

Group travel times of 18.6 kHz whistler-mode signals from NLK, Seattle, to Wellington, New Zealand, are now being measured using the normal FSK transmissions. This is done using a mini-computer programmed to perform real-time cross correlations between two receivers: one receiver gets its signal from a whip aerial on which the ground wave (subionospheric mode) dominates, while the other gets its signal from a loop oriented for minimum ground wave. Group travel time can thus be measured continuously while there are whistler-mode signals present. Delays of 0.2--0.8 seconds have been found

d,l-Sulforaphane Induces ROS-Dependent Apoptosis in Human Gliomablastoma Cells by Inactivating STAT3 Signaling Pathway

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Ziwei Miao

2017-01-01

Full Text Available d,l-Sulforaphane (SFN, a synthetic analogue of broccoli-derived isomer l-SFN, exerts cytotoxic effects on multiple tumor cell types through different mechanisms and is more potent than the l-isomer at inhibiting cancer growth. However, the means by which SFN impairs glioblastoma (GBM cells remains poorly understood. In this study, we investigated the anti-cancer effect of SFN in GBM cells and determined the underlying molecular mechanisms. Cell viability assays, flow cytometry, immunofluorescence, and Western blot results revealed that SFN could induced apoptosis of GBM cells in a dose- and time-dependent manner, via up-regulation of caspase-3 and Bax, and down-regulation of Bcl-2. Mechanistically, SFN treatment led to increase the intracellular reactive oxygen species (ROS level in GBM cells. Meanwhile, SFN also suppressed both constitutive and IL-6-induced phosphorylation of STAT3, and the activation of upstream JAK2 and Src tyrosine kinases, dose- and time-dependently. Moreover, blockage of ROS production by using the ROS inhibitor N-acetyl-l-cysteine totally reversed SFN-mediated down-regulation of JAK2/Src-STAT3 signaling activation and the subsequent effects on apoptosis by blocking the induction of apoptosis-related genes in GBM cells. Taken together, our data suggests that SFN induces apoptosis in GBM cells via ROS-dependent inactivation of STAT3 phosphorylation. These findings motivate further evaluation of SFN as a cancer chemopreventive agent in GBM treatment.

Up-regulation of ROS by mitochondria-dependent bystander signaling contributes to genotoxicity of bystander effects

Energy Technology Data Exchange (ETDEWEB)

Chen Shaopeng [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Zhao Ye; Zhao Guoping [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Han Wei [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Bao Lingzhi [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, K.N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Wu Lijun, E-mail: ljw@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2009-06-18

Genomic instability can be observed in bystander cells. However, the underlying mechanism(s) is still relatively unclear. In a previous study, we found that irradiated cells released mitochondria-dependent intracellular factor(s) which could lead to bystander {gamma}-H2AX induction. In this paper, we used normal ({rho}{sup +}) and mtDNA-depleted ({rho}{sup 0}) human-hamster hybrid cells to investigate mitochondrial effects on the genotoxicity in bystander effect through medium transfer experiments. Through the detection of DNA double-strand breaks with {gamma}-H2AX, we found that the fraction of {gamma}-H2AX positive cells changed with time when irradiation conditioned cell medium (ICCM) were harvested. ICCM harvested from irradiated {rho}{sup +} cells at 10 min post-irradiation ({rho}{sup +} ICCM{sub 10min}) caused larger increases of bystander {gamma}-H2AX induction comparing to {rho}{sup 0} ICCM{sub 10min}, which only caused a slight increase of bystander {gamma}-H2AX induction. The {rho}{sup +} ICCM{sub 10min} could also result in the up-regulation of ROS production (increased by 35% at 10 min), while there was no significant increase in cells treated with {rho}{sup 0} ICCM{sub 10min}. We treated cells with dimethyl sulfoxide (DMSO), the scavenger of ROS, and quenched {gamma}-H2AX induction by {rho}{sup +} ICCM. Furthermore, after the medium had been transferred and the cells were continuously cultured for 7 days, we found significantly increased CD59{sup -} gene loci mutation (increased by 45.9%) and delayed cell death in the progeny of {rho}{sup +} ICCM-treated bystander cells. In conclusion, the work presented here suggested that up-regulation of the mitochondria-dependent ROS might be very important in mediating genotoxicity of bystander effects.

Research On Variable-Length Transfer Delay and Delayed Signal Cancellation Based PLLs

DEFF Research Database (Denmark)

Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

2018-01-01

large frequency drifts are anticipated and a high accuracy is required. To the best of authors' knowledge, the small-signal modeling of a variable-length delay-based PLL has not yet been conducted. The main aim of this paper is to cover this gap. The tuning procedure and analysis of these PLLs...

Unravelling how plants benefit from ROS and NO reactions, while resisting oxidative stress.

Science.gov (United States)

Considine, Michael J; Sandalio, Luisa Maria; Foyer, Christine Helen

2015-09-01

Reactive oxygen species (ROS) and reactive nitrogen species (RNS), such as nitric oxide (NO), play crucial roles in the signal transduction pathways that regulate plant growth, development and defence responses, providing a nexus of reduction/oxidation (redox) control that impacts on nearly every aspect of plant biology. Here we summarize current knowledge and concepts that lay the foundations of a new vision for ROS/RNS functions – particularly through signalling hubs – for the next decade. Plants have mastered the art of redox control using ROS and RNS as secondary messengers to regulate a diverse range of protein functions through redox-based, post-translational modifications that act as regulators of molecular master-switches. Much current focus concerns the impact of this regulation on local and systemic signalling pathways, as well as understanding how such reactive molecules can be effectively used in the control of plant growth and stress responses. The spectre of oxidative stress still overshadows much of our current philosophy and understanding of ROS and RNS functions. While many questions remain to be addressed – for example regarding inter-organellar regulation and communication, the control of hypoxia and how ROS/RNS signalling is used in plant cells, not only to trigger acclimation responses but also to create molecular memories of stress – it is clear that ROS and RNS function as vital signals of living cells.

ROS and myokines promote muscle adaptation to exercise

DEFF Research Database (Denmark)

Scheele, Camilla; Nielsen, Søren; Pedersen, Bente K

2009-01-01

in skeletal muscle. In fact, it seems that exercise-induced ROS are able to stimulate cytokine production from skeletal muscle. Despite the initial view that ROS were potentially cell damaging, it now seems possible that these substances have important roles in the regulation of cell signaling. Muscle......-derived cytokines, so-called 'myokines', are distinguished from inflammation and instead possess important anti-inflammatory and metabolic properties. In this opinion piece, we suggest that both ROS and myokines are important players in muscle adaptation to exercise....

Calcium oxalate crystals induces tight junction disruption in distal renal tubular epithelial cells by activating ROS/Akt/p38 MAPK signaling pathway.

Science.gov (United States)

Yu, Lei; Gan, Xiuguo; Liu, Xukun; An, Ruihua

2017-11-01

Tight junction plays important roles in regulating paracellular transports and maintaining cell polarity. Calcium oxalate monohydrate (COM) crystals, the major crystalline composition of kidney stones, have been demonstrated to be able to cause tight junction disruption to accelerate renal cell injury. However, the cellular signaling involved in COM crystal-induced tight junction disruption remains largely to be investigated. In the present study, we proved that COM crystals induced tight junction disruption by activating ROS/Akt/p38 MAPK pathway. Treating Madin-Darby canine kidney (MDCK) cells with COM crystals induced a substantial increasing of ROS generation and activation of Akt that triggered subsequential activation of ASK1 and p38 mitogen-activated protein kinase (MAPK). Western blot revealed a significantly decreased expression of ZO-1 and occludin, two important structural proteins of tight junction. Besides, redistribution and dissociation of ZO-1 were observed by COM crystals treatment. Inhibition of ROS by N-acetyl-l-cysteine (NAC) attenuated the activation of Akt, ASK1, p38 MAPK, and down-regulation of ZO-1 and occludin. The redistribution and dissociation of ZO-1 were also alleviated by NAC treatment. These results indicated that ROS were involved in the regulation of tight junction disruption induced by COM crystals. In addition, the down-regulation of ZO-1 and occludin, the phosphorylation of ASK1 and p38 MAPK were also attenuated by MK-2206, an inhibitor of Akt kinase, implying Akt was involved in the disruption of tight junction upstream of p38 MAPK. Thus, these results suggested that ROS-Akt-p38 MAPK signaling pathway was activated in COM crystal-induced disruption of tight junction in MDCK cells.

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.

Hyperoxia activates ATM independent from mitochondrial ROS and dysfunction.

Science.gov (United States)

Resseguie, Emily A; Staversky, Rhonda J; Brookes, Paul S; O'Reilly, Michael A

2015-08-01

High levels of oxygen (hyperoxia) are often used to treat individuals with respiratory distress, yet prolonged hyperoxia causes mitochondrial dysfunction and excessive reactive oxygen species (ROS) that can damage molecules such as DNA. Ataxia telangiectasia mutated (ATM) kinase is activated by nuclear DNA double strand breaks and delays hyperoxia-induced cell death through downstream targets p53 and p21. Evidence for its role in regulating mitochondrial function is emerging, yet it has not been determined if mitochondrial dysfunction or ROS activates ATM. Because ATM maintains mitochondrial homeostasis, we hypothesized that hyperoxia induces both mitochondrial dysfunction and ROS that activate ATM. In A549 lung epithelial cells, hyperoxia decreased mitochondrial respiratory reserve capacity at 12h and basal respiration by 48 h. ROS were significantly increased at 24h, yet mitochondrial DNA double strand breaks were not detected. ATM was not required for activating p53 when mitochondrial respiration was inhibited by chronic exposure to antimycin A. Also, ATM was not further activated by mitochondrial ROS, which were enhanced by depleting manganese superoxide dismutase (SOD2). In contrast, ATM dampened the accumulation of mitochondrial ROS during exposure to hyperoxia. Our findings suggest that hyperoxia-induced mitochondrial dysfunction and ROS do not activate ATM. ATM more likely carries out its canonical response to nuclear DNA damage and may function to attenuate mitochondrial ROS that contribute to oxygen toxicity. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

The role of 12/15-lipoxygenases in ROS-mediated neuronal cell death

OpenAIRE

Tobaben, Svenja

2011-01-01

Oxidative stress has been established as a key trigger of neuronal dysfunction and death in age-related neurodegenerative diseases and in delayed neuronal death after acute brain injury by ischemic stroke or brain trauma. Despite increasing knowledge on the toxicity of reactive oxygen species (ROS) and oxidized reaction products that may further accelerate neuronal cell death, the major sources of ROS formation and the mechanisms ...

Delays at signalized intersections with exhaustive traffic control

NARCIS (Netherlands)

Boon, M.A.A.; Adan, I.J.B.F.; Winands, E.M.M.; Down, D.G.

2012-01-01

In this paper, we study a traffic intersection with vehicle-actuated traffic signal control. Traffic lights stay green until all lanes within a group are emptied. Assuming general renewal arrival processes, we derive exact limiting distributions of the delays under heavy traffic (HT) conditions.

Minoxidil sulfate induced the increase in blood-brain tumor barrier permeability through ROS/RhoA/PI3K/PKB signaling pathway.

Science.gov (United States)

Gu, Yan-ting; Xue, Yi-xue; Wang, Yan-feng; Wang, Jin-hui; Chen, Xia; ShangGuan, Qian-ru; Lian, Yan; Zhong, Lei; Meng, Ying-nan

2013-12-01

Adenosine 5'-triphosphate-sensitive potassium channel (KATP channel) activator, minoxidil sulfate (MS), can selectively increase the permeability of the blood-tumor barrier (BTB); however, the mechanism by which this occurs is still under investigation. Using a rat brain glioma (C6) model, we first examined the expression levels of occludin and claudin-5 at different time points after intracarotid infusion of MS (30 μg/kg/min) by western blotting. Compared to MS treatment for 0 min group, the protein expression levels of occludin and claudin-5 in brain tumor tissue of rats showed no changes within 1 h and began to decrease significantly after 2 h of MS infusion. Based on these findings, we then used an in vitro BTB model and selective inhibitors of diverse signaling pathways to investigate whether reactive oxygen species (ROS)/RhoA/PI3K/PKB pathway play a key role in the process of the increase of BTB permeability induced by MS. The inhibitor of ROS or RhoA or PI3K or PKB significantly attenuated the expression of tight junction (TJ) protein and the increase of the BTB permeability after 2 h of MS treatment. In addition, the significant increases in RhoA activity and PKB phosphorylation after MS administration were observed, which were partly inhibited by N-2-mercaptopropionyl glycine (MPG) or C3 exoenzyme or LY294002 pretreatment. The present study indicates that the activation of signaling cascades involving ROS/RhoA/PI3K/PKB in BTB was required for the increase of BTB permeability induced by MS. Taken together, all of these results suggested that MS might increase BTB permeability in a time-dependent manner by down-regulating TJ protein expression and this effect could be related to ROS/RhoA/PI3K/PKB signal pathway. Copyright © 2013 Elsevier Ltd. All rights reserved.

Nox2-dependent ROS signaling protects against skeletal ageing

Science.gov (United States)

Bone remodeling is age-dependently regulated and changes dramatically during the course of development. Progressive accumulation of reactive oxygen species (ROS), including superoxide, hydrogen peroxide, and hydroxyl radicals, has been suspected to be the leading cause of many inflammatory and degen...

Muramyl dipeptide (MDP) induces reactive oxygen species (ROS) generation via the NOD2/COX-2/NOX4 signaling pathway in human umbilical vein endothelial cells (HUVECs).

Science.gov (United States)

Kong, Ling-Jun; Liu, Xiao-Qian; Xue, Ying; Gao, Wei; Lv, Qian-Zhou

2018-03-20

Vascular endothelium dysfunction caused by oxidative stress accelerates the pathologic process of cardiovascular diseases. NOD2, an essential receptor of innate immune system, has been demonstrated to play a critical role in atherosclerosis. Here, the aim of our study was to investigate the effect and underlying molecular mechanism of muramyl dipeptide (MDP) on NOX4-mediated ROS generation in human umbilical vein endothelial cells (HUVECs). 2,7-dichlorofluorescein diacetate staining was to measure the intracellular ROS level and showed MDP promoted ROS production in a time- and dose-dependent manner. The mRNA and protein levels of NOX4 and COX-2 were detected by real-time PCR and western blot. Small interfering RNA (siRNA) was used to silence NOD2 or COX-2 gene expression and investigate the mechanism of NOD2-mediated signaling pathway in HUVECs. Data showed that MDP induced NOX4 and COX-2 expression in a time- and dose-dependent manner. NOD2 knock-down suppressed up-regulation of COX-2 and NOX4 in HUVECs treated with MDP. Furthermore, silence of COX-2 in HUVECs down-regulated the NOX4 expression after MDP stimulation. Collectively, we indicated that NOD2 played a leading role in MDP-induced COX-2/NOX4/ROS signaling pathway in HUVECs, which was a novel regulatory mechanism in the progress of ROS generation.

Feedforward Delay Estimators in Adverse Multipath Propagation for Galileo and Modernized GPS Signals

Directory of Open Access Journals (Sweden)

Lohan Elena Simona

2006-01-01

Full Text Available The estimation with high accuracy of the line-of-sight delay is a prerequisite for all global navigation satellite systems. The delay locked loops and their enhanced variants are the structures of choice for the commercial GNSS receivers, but their performance in severe multipath scenarios is still rather limited. The new satellite positioning system proposals specify higher code-epoch lengths compared to the traditional GPS signal and the use of a new modulation, the binary offset carrier (BOC modulation, which triggers new challenges in the delay tracking stage. We propose and analyze here the use of feedforward delay estimation techniques in order to improve the accuracy of the delay estimation in severe multipath scenarios. First, we give an extensive review of feedforward delay estimation techniques for CDMA signals in fading channels, by taking into account the impact of BOC modulation. Second, we extend the techniques previously proposed by the authors in the context of wideband CDMA delay estimation (e.g., Teager-Kaiser and the projection onto convex sets to the BOC-modulated signals. These techniques are presented as possible alternatives to the feedback tracking loops. A particular attention is on the scenarios with closely spaced paths. We also discuss how these feedforward techniques can be implemented via DSPs.

Acidic environment leads to ROS-induced MAPK signaling in cancer cells.

Directory of Open Access Journals (Sweden)

Anne Riemann

Full Text Available Tumor micromilieu often shows pronounced acidosis forcing cells to adapt their phenotype towards enhanced tumorigenesis induced by altered cellular signalling and transcriptional regulation. In the presents study mechanisms and potential consequences of the crosstalk between extra- and intracellular pH (pH(e, pH(i and mitogen-activated-protein-kinases (ERK1/2, p38 was analyzed. Data were obtained mainly in AT1 R-3327 prostate carcinoma cells, but the principle importance was confirmed in 5 other cell types. Extracellular acidosis leads to a rapid and sustained decrease of pH(i in parallel to p38 phosphorylation in all cell types and to ERK1/2 phosphorylation in 3 of 6 cell types. Furthermore, p38 phosphorylation was elicited by sole intracellular lactacidosis at normal pH(e. Inhibition of ERK1/2 phosphorylation during acidosis led to necrotic cell death. No evidence for the involvement of the kinases c-SRC, PKC, PKA, PI3K or EGFR nor changes in cell volume in acidosis-induced MAPK activation was obtained. However, our data reveal that acidosis enhances the formation of reactive oxygen species (ROS, probably originating from mitochondria, which subsequently trigger MAPK phosphorylation. Scavenging of ROS prevented acidosis-induced MAPK phosphorylation whereas addition of H(2O(2 enhanced it. Finally, acidosis increased phosphorylation of the transcription factor CREB via p38, leading to increased transcriptional activity of a CRE-reporter even 24 h after switching the cells back to a normal environmental milieu. Thus, an acidic tumor microenvironment can induce a longer lasting p38-CREB-medited change in the transcriptional program, which may maintain the altered phenotype even when the cells leave the tumor environment.

Real-time traffic signal optimization model based on average delay time per person

Directory of Open Access Journals (Sweden)

Pengpeng Jiao

2015-10-01

Full Text Available Real-time traffic signal control is very important for relieving urban traffic congestion. Many existing traffic control models were formulated using optimization approach, with the objective functions of minimizing vehicle delay time. To improve people’s trip efficiency, this article aims to minimize delay time per person. Based on the time-varying traffic flow data at intersections, the article first fits curves of accumulative arrival and departure vehicles, as well as the corresponding functions. Moreover, this article transfers vehicle delay time to personal delay time using average passenger load of cars and buses, employs such time as the objective function, and proposes a signal timing optimization model for intersections to achieve real-time signal parameters, including cycle length and green time. This research further implements a case study based on practical data collected at an intersection in Beijing, China. The average delay time per person and queue length are employed as evaluation indices to show the performances of the model. The results show that the proposed methodology is capable of improving traffic efficiency and is very effective for real-world applications.

The ROS-mediated activation of IL-6/STAT3 signaling pathway is involved in the 27-hydroxycholesterol-induced cellular senescence in nerve cells.

Science.gov (United States)

Liu, Jiao; Liu, Yun; Chen, Juan; Hu, Chunyan; Teng, Mengying; Jiao, Kailin; Shen, Zhaoxia; Zhu, Dongmei; Yue, Jia; Li, Zhong; Li, Yuan

2017-12-01

The oxysterol 27-hydroxycholesterol (27HC) is a selective estrogen receptor modulator (SERMs), which like endogenous estrogen 17β-estradiol (E 2 ) induces the proliferation of ER-positive breast cancer cells in vitro. Interestingly, the observation that 27HC induces adverse effects in neural system, distinguishing it from E 2 . It has been suggested that high levels of circulating cholesterol increase the entry of 27HC into the brain, which may induce learning and memory impairment. Based on this evidence, 27HC may be associated with neurodegenerative processes and interrupted cholesterol homeostasis in the brain. However, the biological events that participate in this process remain largely elusive. In the present study, we demonstrated that 27HC induced apparent cellular senescence in nerve cells. Senescence-associated β-galactosidase (SA-β-Gal) assay revealed that 27HC induced senescence in both BV2 cells and PC12 cells. Furthermore, we demonstrated that 27HC promoted the accumulation of cellular reactive oxygen species (ROS) in nerve cells and subsequently activation of IL-6/STAT3 signaling pathway. Notably, treatment with the ROS scavenger N-acetylcysteine (NAC) markedly blocked 27HC-induced ROS production and activation of IL-6/STAT3 signaling pathway. Either blocking the generation of ROS or inhibition of IL-6/STAT3 both attenuated 27HC-induced cellular senescence. In sum, these findings not only suggested a mechanism whereby 27HC induced cellular senescence in nerve cells, but also helped to recognize the 27HC as a novel harmful factor in neurodegenerative diseases. Copyright © 2017. Published by Elsevier Ltd.

Protective effects of andrographolide analogue AL-1 on ROS-induced RIN-mβ cell death by inducing ROS generation.

Directory of Open Access Journals (Sweden)

Guang-Rong Yan

Full Text Available Oxidative stress is considered to be a major factor contributing to pathogenesis and progression of many diseases. A novel andrographolide-lipoic acid conjugate (AL-1 could protect pancreatic β-cells from reactive oxygen species (ROS-induced oxidative injury. However, its protective mechanism is still unclear. In this work, we used proteomics to identify AL-1-regulated proteins in β-cells and found that 13 of the 71 proteins regulated by AL-1 were closely associated with antioxidation. These differential proteins were mainly involved in the ERK1/2 and AKT1 signaling pathways. Functional investigation demonstrated that AL-1 exerted its protective effects on H2O2-induced cell death of β-cells by generating NADPH oxidase-dependent ROS to activate ERK1/2 and AKT1 signaling pathways. As a consequence, the expressions of antioxidant proteins including Trx1, Prx1 and Prx5, and anti-apoptotic proteins including PDCD6IP, prohibitin, galectin-1 and HSP were upregulated. AL-1 probably worked as a "vaccinum" to activate the cellular antioxidant system by inducing the generation of low concentration ROS which then reciprocally protected β-cells from oxidative damage caused by high-level ROS from H2O2. To the best of our knowledge, this is the first comprehensive proteomic analysis illustrating a novel molecular mechanism for the protective effects of antioxidants on β-cells from H2O2-induced cell death.

Picrasidine I from Picrasma Quassioides Suppresses Osteoclastogenesis via Inhibition of RANKL Induced Signaling Pathways and Attenuation of ROS Production

Directory of Open Access Journals (Sweden)

Lingbo Kong

2017-10-01

Full Text Available Background/Aims: Osteoporosis is a metabolic bone disorder that tortures about millions of people worldwide. Recent study demonstrated agents derived from picrasma quassioides is a promising drug for targets multiple signaling pathways. However its potential in treatment of bone loss has not been fully understood. Methods: The bone marrow macrophages (BMMs were cultured and induced with M-CSF and RANKL followed by picrasidine I (PI treatment. Then the effects of PI on osteoclast formation were evaluated by counting tartrate-resistant acid phosphatase (TRAP-positive multinucleated cells. Moreover, effects of PI on bone resorption activity of mature osteoclast were studied through bone resorption pit counting and actin ring structure analysis. Further, the involved potential signaling pathways cross-talking were investigated by performed Western blotting and quantitative real-time PCR examination. Results: Results demonstrated PI strongly inhibited RANKL induced osteoclast formation from its precursors. Mechanistically, the inhibitory effect of PI on osteoclast differentiation was due to the suppression of osteoclastogenic transcription factors, c-Fos and NFATc1. Moreover, PI markedly blocked the RANKL-induced osteoclastogenesis by attenuating MAPKs and NF-κB signaling pathways. In addition, PI decreased the ROS generation in osteoclast and osteoblast. Conclusion: Taken together our data demonstrate that PI has antiosteoclastogenic effect by inhibiting inflammation induced activation of MAPKs, NF-κB and ROS generation followed by suppressing the gene expression of c-Fos and NFATc1 in osteoclast precursors.

Oxidative stress activates the TRPM2-Ca2+-CaMKII-ROS signaling loop to induce cell death in cancer cells.

Science.gov (United States)

Wang, Qian; Huang, Lihong; Yue, Jianbo

2017-06-01

High intracellular levels of reactive oxygen species (ROS) cause oxidative stress that results in numerous pathologies, including cell death. Transient potential receptor melastatin-2 (TRPM2), a Ca 2+ -permeable cation channel, is mainly activated by intracellular adenosine diphosphate ribose (ADPR) in response to oxidative stress. Here we studied the role and mechanisms of TRPM2-mediated Ca 2+ influx on oxidative stress-induced cell death in cancer cells. We found that oxidative stress activated the TRPM2-Ca 2+ -CaMKII cascade to inhibit early autophagy induction, which ultimately led to cell death in TRPM2 expressing cancer cells. On the other hand, TRPM2 knockdown switched cells from cell death to autophagy for survival in response to oxidative stress. Moreover, we found that oxidative stress activated the TRPM2-CaMKII cascade to further induce intracellular ROS production, which led to mitochondria fragmentation and loss of mitochondrial membrane potential. In summary, our data demonstrated that oxidative stress activates the TRPM2-Ca 2+ -CaMKII-ROS signal loop to inhibit autophagy and induce cell death. Copyright © 2016 Elsevier B.V. All rights reserved.

PKCδ phosphorylation is an upstream event of GSK3 inactivation-mediated ROS generation in TGF-β1-induced senescence.

Science.gov (United States)

Byun, H-O; Jung, H-J; Kim, M-J; Yoon, G

2014-09-01

Transforming growth factor β1 (TGF-β1) induces Mv1Lu cell senescence through inactivating glycogen synthase kinase 3 (GSK3), thereby inactivating complex IV and increasing intracellular ROS. In the present study, we identified protein kinase C delta (PKCδ) as an upstream regulator of GSK3 inactivation in this mechanism of TGF-β1-induced senescence. When Mv1Lu cells were exposed to TGF-β1, PKCδ phosphorylation simultaneously increased with GSK3 phosphorylation, and then AKT and ERK were phosphorylated. AKT phosphorylation and Smad signaling were independent of GSK3 phosphorylation, but ERK phosphorylation was downstream of GSK3 inactivation. TGF-β1-triggered GSK3 phosphorylation was blocked by inhibition of PKCδ, using its pharmacological inhibitor, Rottlerin, or overexpression of a dominant negative PKCδ mutant, but GSK3 inhibition with SB415286 did not alter PKCδ phosphorylation. Activation of PKCδ by PMA delayed cell growth and increased intracellular ROS level, but did not induce senescent phenotypes. In addition, overexpression of wild type or a constitutively active PKCδ mutant was enough to delay cell growth and decrease the mitochondrial oxygen consumption rate and complex IV activity, but weakly induce senescence. However, PMA treatment on Mv1Lu cells, which overexpress wild type and constitutively active PKCδ mutants, effectively induced senescence. These results indicate that PKCδ plays a key role in TGF-β1-induced senescence of Mv1Lu cells through the phosphorylation of GSK3, thereby triggering mitochondrial complex IV dysfunction and intracellular ROS generation.

Delayed Dopamine Signaling of Energy Level Builds Appetitive Long-Term Memory in Drosophila

OpenAIRE

Pierre-Yves Musso; Paul Tchenio; Thomas Preat

2015-01-01

Sensory cues relevant to a food source, such as odors, can be associated with post-ingestion signals related either to food energetic value or toxicity. Despite numerous behavioral studies, a global understanding of the mechanisms underlying these long delay associations remains out of reach. Here, we demonstrate in Drosophila that the long-term association between an odor and a nutritious sugar depends on delayed post-ingestion signaling of energy level. We show at the neural circuit level t...

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.

Delay Pressure Detection Method to Eliminate Pump Pressure Interference on the Downhole Mud Pressure Signals

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Yue Shen

2013-01-01

Full Text Available The feasibility of applying delay pressure detection method to eliminate mud pump pressure interference on the downhole mud pressure signals is studied. Two pressure sensors mounted on the mud pipe in some distance apart are provided to detect the downhole mud continuous pressure wave signals on the surface according to the delayed time produced by mud pressure wave transmitting between the two sensors. A mathematical model of delay pressure detection is built by analysis of transmission path between mud pump pressure interference and downhole mud pressure signals. Considering pressure signal transmission characteristics of the mud pipe, a mathematical model of ideal low-pass filter for limited frequency band signal is introduced to study the pole frequency impact on the signal reconstruction and the constraints of pressure sensor distance are obtained by pole frequencies analysis. Theoretical calculation and numerical simulation show that the method can effectively eliminate mud pump pressure interference and the downhole mud continuous pressure wave signals can be reconstructed successfully with a significant improvement in signal-to-noise ratio (SNR in the condition of satisfying the constraints of pressure sensor distance.

Delayed Dopamine Signaling of Energy Level Builds Appetitive Long-Term Memory in Drosophila

Directory of Open Access Journals (Sweden)

Pierre-Yves Musso

2015-02-01

Full Text Available Sensory cues relevant to a food source, such as odors, can be associated with post-ingestion signals related either to food energetic value or toxicity. Despite numerous behavioral studies, a global understanding of the mechanisms underlying these long delay associations remains out of reach. Here, we demonstrate in Drosophila that the long-term association between an odor and a nutritious sugar depends on delayed post-ingestion signaling of energy level. We show at the neural circuit level that the activity of two pairs of dopaminergic neurons is necessary and sufficient to signal energy level to the olfactory memory center. Accordingly, we have identified in these dopaminergic neurons a delayed calcium trace that correlates with appetitive long-term memory formation. Altogether, these findings demonstrate that the Drosophila brain remembers food quality through a two-step mechanism that consists of the integration of olfactory and gustatory sensory information and then post-ingestion energetic value.

Delayed dopamine signaling of energy level builds appetitive long-term memory in Drosophila.

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Musso, Pierre-Yves; Tchenio, Paul; Preat, Thomas

2015-02-24

Sensory cues relevant to a food source, such as odors, can be associated with post-ingestion signals related either to food energetic value or toxicity. Despite numerous behavioral studies, a global understanding of the mechanisms underlying these long delay associations remains out of reach. Here, we demonstrate in Drosophila that the long-term association between an odor and a nutritious sugar depends on delayed post-ingestion signaling of energy level. We show at the neural circuit level that the activity of two pairs of dopaminergic neurons is necessary and sufficient to signal energy level to the olfactory memory center. Accordingly, we have identified in these dopaminergic neurons a delayed calcium trace that correlates with appetitive long-term memory formation. Altogether, these findings demonstrate that the Drosophila brain remembers food quality through a two-step mechanism that consists of the integration of olfactory and gustatory sensory information and then post-ingestion energetic value. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Stochastic resonance in a bistable system subject to multi-time-delayed feedback and aperiodic signal

International Nuclear Information System (INIS)

Li Jianlong; Zeng Lingzao

2010-01-01

We discuss in detail the effects of the multi-time-delayed feedback driven by an aperiodic signal on the output of a stochastic resonance (SR) system. The effective potential function and dynamical probability density function (PDF) are derived. To measure the performance of the SR system in the presence of a binary random signal, the bit error rate (BER) defined by the dynamical PDF is employed, as is commonly used in digital communications. We find that the delay time, strength of the feedback, and number of time-delayed terms can change the effective potential function and the effective amplitude of the signal, and then affect the BER of the SR system. The numerical simulations strongly support the theoretical results. The goal of this investigation is to explore the effects of the multi-time-delayed feedback on SR and give a guidance to nonlinear systems in the application of information processing.

Activation of PAR-1/NADPH Oxidase/ROS Signaling Pathways is Crucial for the Thrombin-Induced sFlt-1 Production in Extravillous Trophoblasts: Possible Involvement in the Pathogenesis of Preeclampsia

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Qi-tao Huang

2015-03-01

Full Text Available Backgrounds/Aims: Preeclampsia was characterized by excessive thrombin generation in placentas and previous researches showed that thrombin could enhance soluble Fms-like tyrosine kinase 1 (sFlt-1 expression in first trimester trophoblasts. However, the detailed mechanism for the sFlt-1 over-production induced by thrombin was largely unknown. The purpose of this study was to explore the possible signaling pathway of thrombin-induced sFlt-1 production in extravillous trophoblasts (EVT. Methods: An EVT cell line (HRT-8/SVneo was treated with various concentrations of thrombin. The mRNA expression and protein secretion of sFlt-1 in EVT were detected with real-time polymerase chain reaction and ELISA, respectively. The levels of intracellular reactive oxygen species (ROS production were determined by DCFH-DA. Results: Exposure of EVT to thrombin induced increased intracellular ROS generation and overexpression of sFlt-1 at both mRNA and protein levels in a dose dependent manner. Short interfering RNA (siRNA directed against PAR-1 or apocynin (an inhibitor of NADPH oxidase could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels. Conclusions: Our results suggested that thrombin increased sFlt-1 production in EVT via the PAR-1 /NADPH oxidase /ROS signaling pathway. This also highlights the PAR-1 / NADPH oxidase / ROS pathway might be a potential therapeutic target for the prevention of preeclampsia in the future.

Activation of PAR-1/NADPH oxidase/ROS signaling pathways is crucial for the thrombin-induced sFlt-1 production in extravillous trophoblasts: possible involvement in the pathogenesis of preeclampsia.

Science.gov (United States)

Huang, Qi-Tao; Chen, Jian-Hong; Hang, Li-Lin; Liu, Shi-San; Zhong, Mei

2015-01-01

Preeclampsia was characterized by excessive thrombin generation in placentas and previous researches showed that thrombin could enhance soluble Fms-like tyrosine kinase 1 (sFlt-1) expression in first trimester trophoblasts. However, the detailed mechanism for the sFlt-1 over-production induced by thrombin was largely unknown. The purpose of this study was to explore the possible signaling pathway of thrombin-induced sFlt-1 production in extravillous trophoblasts (EVT). An EVT cell line (HRT-8/SVneo) was treated with various concentrations of thrombin. The mRNA expression and protein secretion of sFlt-1 in EVT were detected with real-time polymerase chain reaction and ELISA, respectively. The levels of intracellular reactive oxygen species (ROS) production were determined by DCFH-DA. Exposure of EVT to thrombin induced increased intracellular ROS generation and overexpression of sFlt-1 at both mRNA and protein levels in a dose dependent manner. Short interfering RNA (siRNA) directed against PAR-1 or apocynin (an inhibitor of NADPH oxidase) could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels. Our results suggested that thrombin increased sFlt-1 production in EVT via the PAR-1 /NADPH oxidase /ROS signaling pathway. This also highlights the PAR-1 / NADPH oxidase / ROS pathway might be a potential therapeutic target for the prevention of preeclampsia in the future. © 2015 S. Karger AG, Basel.

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)

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.

Impact of MAC Delay on AUV Localization: Underwater Localization Based on Hyperbolic Frequency Modulation Signal.

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Kim, Sungryul; Yoo, Younghwan

2018-01-26

Medium Access Control (MAC) delay which occurs between the anchor node's transmissions is one of the error sources in underwater localization. In particular, in AUV localization, the MAC delay significantly degrades the ranging accuracy. The Cramer-Rao Low Bound (CRLB) definition theoretically proves that the MAC delay significantly degrades the localization performance. This paper proposes underwater localization combined with multiple access technology to decouple the localization performance from the MAC delay. Towards this goal, we adopt hyperbolic frequency modulation (HFM) signal that provides multiplexing based on its good property, high-temporal correlation. Owing to the multiplexing ability of the HFM signal, the anchor nodes can transmit packets without MAC delay, i.e., simultaneous transmission is possible. In addition, the simulation results show that the simultaneous transmission is not an optional communication scheme, but essential for the localization of mobile object in underwater.

Hypoxia Downregulates MAPK/ERK but Not STAT3 Signaling in ROS-Dependent and HIF-1-Independent Manners in Mouse Embryonic Stem Cells

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Jan Kučera

2017-01-01

Full Text Available Hypoxia is involved in the regulation of stem cell fate, and hypoxia-inducible factor 1 (HIF-1 is the master regulator of hypoxic response. Here, we focus on the effect of hypoxia on intracellular signaling pathways responsible for mouse embryonic stem (ES cell maintenance. We employed wild-type and HIF-1α-deficient ES cells to investigate hypoxic response in the ERK, Akt, and STAT3 pathways. Cultivation in 1% O2 for 24 h resulted in the strong dephosphorylation of ERK and its upstream kinases and to a lesser extent of Akt in an HIF-1-independent manner, while STAT3 phosphorylation remained unaffected. Downregulation of ERK could not be mimicked either by pharmacologically induced hypoxia or by the overexpression. Dual-specificity phosphatases (DUSP 1, 5, and 6 are hypoxia-sensitive MAPK-specific phosphatases involved in ERK downregulation, and protein phosphatase 2A (PP2A regulates both ERK and Akt. However, combining multiple approaches, we revealed the limited significance of DUSPs and PP2A in the hypoxia-mediated attenuation of ERK signaling. Interestingly, we observed a decreased reactive oxygen species (ROS level in hypoxia and a similar phosphorylation pattern for ERK when the cells were supplemented with glutathione. Therefore, we suggest a potential role for the ROS-dependent attenuation of ERK signaling in hypoxia, without the involvement of HIF-1.

Hyperoxia-induced p47phox activation and ROS generation is mediated through S1P transporter Spns2, and S1P/S1P1&2 signaling axis in lung endothelium.

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Harijith, Anantha; Pendyala, Srikanth; Ebenezer, David L; Ha, Alison W; Fu, Panfeng; Wang, Yue-Ting; Ma, Ke; Toth, Peter T; Berdyshev, Evgeny V; Kanteti, Prasad; Natarajan, Viswanathan

2016-08-01

Hyperoxia-induced lung injury adversely affects ICU patients and neonates on ventilator assisted breathing. The underlying culprit appears to be reactive oxygen species (ROS)-induced lung damage. The major contributor of hyperoxia-induced ROS is activation of the multiprotein enzyme complex NADPH oxidase. Sphingosine-1-phosphate (S1P) signaling is known to be involved in hyperoxia-mediated ROS generation; however, the mechanism(s) of S1P-induced NADPH oxidase activation is unclear. Here, we investigated various steps in the S1P signaling pathway mediating ROS production in response to hyperoxia in lung endothelium. Of the two closely related sphingosine kinases (SphKs)1 and 2, which synthesize S1P from sphingosine, only Sphk1(-/-) mice conferred protection against hyperoxia-induced lung injury. S1P is metabolized predominantly by S1P lyase and partial deletion of Sgpl1 (Sgpl1(+/-)) in mice accentuated lung injury. Hyperoxia stimulated S1P accumulation in human lung microvascular endothelial cells (HLMVECs), and downregulation of S1P transporter spinster homolog 2 (Spns2) or S1P receptors S1P1&2, but not S1P3, using specific siRNA attenuated hyperoxia-induced p47(phox) translocation to cell periphery and ROS generation in HLMVECs. These results suggest a role for Spns2 and S1P1&2 in hyperoxia-mediated ROS generation. In addition, p47(phox) (phox:phagocyte oxidase) activation and ROS generation was also reduced by PF543, a specific SphK1 inhibitor in HLMVECs. Our data indicate a novel role for Spns2 and S1P1&2 in the activation of p47(phox) and production of ROS involved in hyperoxia-mediated lung injury in neonatal and adult mice. Copyright © 2016 the American Physiological Society.

ROS Are Required for Mouse Spermatogonial Stem Cell Self-Renewal

OpenAIRE

Morimoto, Hiroko; Iwata, Kazumi; Ogonuki, Narumi; Inoue, Kimiko; Ogura, Atsuo; Kanatsu-Shinohara, Mito; Morimoto, Takeshi; Yabe-Nishimura, Chihiro; Shinohara, Takashi

2013-01-01

Reactive oxygen species (ROS) generation is implicated in stem cell self-renewal in several tissues but is thought to be detrimental for spermatogenesis as well as spermatogonial stem cells (SSCs). Using cultured SSCs, we show that ROS are generated via the AKT and MEK signaling pathways under conditions where the growth factors glial cell line-derived neurotrophic factor and fibroblast growth factor 2 drive SSC self-renewal and, instead, stimulate self-renewal at physiological levels. SSCs d...

Low Emissions and Delay Optimization for an Isolated Signalized Intersection Based on Vehicular Trajectories.

Science.gov (United States)

Lin, Ciyun; Gong, Bowen; Qu, Xin

2015-01-01

A traditional traffic signal control system is established based on vehicular delay, queue length, saturation and other indicators. However, due to the increasing severity of urban environmental pollution issues and the development of a resource-saving and environmentally friendly social philosophy, the development of low-carbon and energy-efficient urban transport is required. This paper first defines vehicular trajectories and the calculation of vehicular emissions based on VSP. Next, a regression analysis method is used to quantify the relationship between vehicular emissions and delay, and a traffic signal control model is established to reduce emissions and delay using the enumeration method combined with saturation constraints. Finally, one typical intersection of Changchun is selected to verify the model proposed in this paper; its performance efficiency is also compared using simulations in VISSIM. The results of this study show that the proposed model can significantly reduce vehicle delay and traffic emissions simultaneously.

Heme-induced ROS in Trypanosoma cruzi activates CaMKII-like that triggers epimastigote proliferation. One helpful effect of ROS.

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Natália Pereira de Almeida Nogueira

Full Text Available Heme is a ubiquitous molecule that has a number of physiological roles. The toxic effects of this molecule have been demonstrated in various models, based on both its pro-oxidant nature and through a detergent mechanism. It is estimated that about 10 mM of heme is released during blood digestion in the blood-sucking bug's midgut. The parasite Trypanosoma cruzi, the agent of Chagas' disease, proliferates in the midgut of the insect vector; however, heme metabolism in trypanosomatids remains to be elucidated. Here we provide a mechanistic explanation for the proliferative effects of heme on trypanosomatids. Heme, but not other porphyrins, induced T. cruzi proliferation, and this phenomenon was accompanied by a marked increase in reactive oxygen species (ROS formation in epimastigotes when monitored by ROS-sensitive fluorescent probes. Heme-induced ROS production was time- and concentration-dependent. In addition, lipid peroxidation and the formation of 4-hydroxy-2-nonenal (4-HNE adducts with parasite proteins were increased in epimastigotes in the presence of heme. Conversely, the antioxidants urate and GSH reversed the heme-induced ROS. Urate also decreased parasite proliferation. Among several protein kinase inhibitors tested only specific inhibitors of CaMKII, KN93 and Myr-AIP, were able to abolish heme-induced ROS formation in epimastigotes leading to parasite growth impairment. Taken together, these data provide new insight into T. cruzi- insect vector interactions: heme, a molecule from the blood digestion, triggers epimastigote proliferation through a redox-sensitive signalling mechanism.

Downregulation of B-myb promotes senescence via the ROS-mediated p53/p21 pathway, in vascular endothelial cells.

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Zhou, Zhihui; Yin, Yanlin; Chang, Qun; Sun, Guanqun; Lin, Jiahui; Dai, Yalei

2017-04-01

To reveal whether B-myb is involved in preventing senescence of vascular endothelial cells, and if so, to identify possible mechanisms for it. C57/BL6 male mice and primary human aortic endothelial cells (HAECs) were used. Bleomycin was applied to induce stress-related premature senescence. B-myb knockdown was achieved using an siRNA technique and cell senescence was assessed using the senescence-associated β-galactosidase (SA-β-gal) assay. Intracellular reactive oxygen species (ROS) production was analysed using an ROS assay kit and cell proliferation was evaluated using KFluor488 EdU kit. Capillary tube network formation was determined by Matrigel assay. Expressions of mRNA and protein levels were detected by real-time PCR and western blotting. B-myb expression significantly decreased, while p53 and p21 expressions increased in the aortas of aged mice. This expression pattern was also found in replicative senescent HAECs and senescent HAECs induced by bleomycin. B-myb knockdown resulted in upregulation of p22 phox , ROS accumulation and cell senescence of HAECs. Downregulation of B-myb significantly inhibited cell proliferation and capillary tube network formation and activated the p53/p21 signalling pathway. Blocking ROS production or inhibiting p53 activation remarkably attenuated SA-β-gal activity and delayed cell senescence induced by B-myb-silencing. Downregulation of B-myb induced senescence by upregulation of p22 phox and activation of the ROS/p53/p21 pathway, in our vascular endothelial cells, suggesting that B-myb may be a novel candidate for regulating cell senescence to protect against endothelial senescence-related cardiovascular diseases. © 2016 John Wiley & Sons Ltd.

Mitochondria and Mitochondrial ROS in Cancer: Novel Targets for Anticancer Therapy.

Science.gov (United States)

Yang, Yuhui; Karakhanova, Svetlana; Hartwig, Werner; D'Haese, Jan G; Philippov, Pavel P; Werner, Jens; Bazhin, Alexandr V

2016-12-01

Mitochondria are indispensable for energy metabolism, apoptosis regulation, and cell signaling. Mitochondria in malignant cells differ structurally and functionally from those in normal cells and participate actively in metabolic reprogramming. Mitochondria in cancer cells are characterized by reactive oxygen species (ROS) overproduction, which promotes cancer development by inducing genomic instability, modifying gene expression, and participating in signaling pathways. Mitochondrial and nuclear DNA mutations caused by oxidative damage that impair the oxidative phosphorylation process will result in further mitochondrial ROS production, completing the "vicious cycle" between mitochondria, ROS, genomic instability, and cancer development. The multiple essential roles of mitochondria have been utilized for designing novel mitochondria-targeted anticancer agents. Selective drug delivery to mitochondria helps to increase specificity and reduce toxicity of these agents. In order to reduce mitochondrial ROS production, mitochondria-targeted antioxidants can specifically accumulate in mitochondria by affiliating to a lipophilic penetrating cation and prevent mitochondria from oxidative damage. In consistence with the oncogenic role of ROS, mitochondria-targeted antioxidants are found to be effective in cancer prevention and anticancer therapy. A better understanding of the role played by mitochondria in cancer development will help to reveal more therapeutic targets, and will help to increase the activity and selectivity of mitochondria-targeted anticancer drugs. In this review we summarized the impact of mitochondria on cancer and gave summary about the possibilities to target mitochondria for anticancer therapies. J. Cell. Physiol. 231: 2570-2581, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

ROS detoxification and proinflammatory cytokines are linked by p38 MAPK signaling in a model of mature astrocyte activation.

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Adrian Nahirnyj

Full Text Available Astrocytes are the most abundant glial cell in the retinal nerve fiber layer (NFL and optic nerve head (ONH, and perform essential roles in maintaining retinal ganglion cell (RGC detoxification and homeostasis. Mature astrocytes are relatively quiescent, but rapidly undergo a phenotypic switch in response to insult, characterized by upregulation of intermediate filament proteins, loss of glutamate buffering, secretion of pro-inflammatory cytokines, and increased antioxidant production. These changes result in both positive and negative influences on RGCs. However, the mechanism regulating these responses is still unclear, and pharmacologic strategies to modulate select aspects of this switch have not been thoroughly explored. Here we describe a system for rapid culture of mature astrocytes from the adult rat retina that remain relatively quiescent, but respond robustly when challenged with oxidative damage, a key pathogenic stress associated with inner retinal injury. When primary astrocytes were exposed to reactive oxygen species (ROS we consistently observed characteristic changes in activation markers, along with increased expression of detoxifying genes, and secretion of proinflammatory cytokines. This in vitro model was then used for a pilot chemical screen to target specific aspects of this switch. Increased activity of p38α and β Mitogen Activated Protein Kinases (MAPKs were identified as a necessary signal regulating expression of MnSOD, and heme oxygenase 1 (HO-1, with consequent changes in ROS-mediated injury. Additionally, multiplex cytokine profiling detected p38 MAPK-dependent secretion of IL-6, MCP-1, and MIP-2α, which are proinflammatory signals recently implicated in damage to the inner retina. These data provide a mechanism to link increased oxidative stress to proinflammatory signaling by astrocytes, and establish this assay as a useful model to further dissect factors regulating the reactive switch.

ROS, Cell Senescence, and Novel Molecular Mechanisms in Aging and Age-Related Diseases

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Pierpaola Davalli

2016-01-01

Full Text Available The aging process worsens the human body functions at multiple levels, thus causing its gradual decrease to resist stress, damage, and disease. Besides changes in gene expression and metabolic control, the aging rate has been associated with the production of high levels of Reactive Oxygen Species (ROS and/or Reactive Nitrosative Species (RNS. Specific increases of ROS level have been demonstrated as potentially critical for induction and maintenance of cell senescence process. Causal connection between ROS, aging, age-related pathologies, and cell senescence is studied intensely. Senescent cells have been proposed as a target for interventions to delay the aging and its related diseases or to improve the diseases treatment. Therapeutic interventions towards senescent cells might allow restoring the health and curing the diseases that share basal processes, rather than curing each disease in separate and symptomatic way. Here, we review observations on ROS ability of inducing cell senescence through novel mechanisms that underpin aging processes. Particular emphasis is addressed to the novel mechanisms of ROS involvement in epigenetic regulation of cell senescence and aging, with the aim to individuate specific pathways, which might promote healthy lifespan and improve aging.

Low Emissions and Delay Optimization for an Isolated Signalized Intersection Based on Vehicular Trajectories.

Directory of Open Access Journals (Sweden)

Ciyun Lin

Full Text Available A traditional traffic signal control system is established based on vehicular delay, queue length, saturation and other indicators. However, due to the increasing severity of urban environmental pollution issues and the development of a resource-saving and environmentally friendly social philosophy, the development of low-carbon and energy-efficient urban transport is required. This paper first defines vehicular trajectories and the calculation of vehicular emissions based on VSP. Next, a regression analysis method is used to quantify the relationship between vehicular emissions and delay, and a traffic signal control model is established to reduce emissions and delay using the enumeration method combined with saturation constraints. Finally, one typical intersection of Changchun is selected to verify the model proposed in this paper; its performance efficiency is also compared using simulations in VISSIM. The results of this study show that the proposed model can significantly reduce vehicle delay and traffic emissions simultaneously.

Variable delay-to-signal: a fast paradigm for assessment of aspects of impulsivity in rats

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Hugo eLeite-Almeida

2013-10-01

Full Text Available Testing impulsive behavior in rodents is challenging and labor-intensive. We developed a new behavioral paradigm – the Variable Delay-to-Signal (VDS test – that provides rapid and simultaneous assessment of response and decision impulsivity in rodents. Presentation of a light at variable delays signals the permission for action (nose poke contingent with a reward. Two blocks of 25 trials at 3s delay flank a block of 70 trials in which light is presented with randomly selected 6s or 12s delays. Exposure to such large delays boosts the rate of premature responses when the delay drops to 3s in the final block, an effect that is blunted by an acute methamphetamine challenge and that correlates with the delay-discounting paradigm (choice impulsivity. Finally, as expected, treatment with the NMDA antagonist MK-801 caused a generalized response increase in all VDS blocks. The pharmacological validation, particularly with methamphetamine which has a well established dual effect on response and decision impulsivity, and the correlations between the impulsive behavior in the delay-discounting and VDS paradigms, suggests that the later is able to provide, in a single session, a multi-dimensional assessment of impulsive behavior.

Extinction ratio enhancement of SOA-based delayed-interference signal converter using detuned filtering

Science.gov (United States)

Zhang, B.; Kumar, S.; Yan, L.-S.; Willner, A. E.

2007-12-01

We demonstrate experimentally >3 dB extinction ratio improvement at the output of SOA-based delayed-interference signal converter (DISC) using optical off-centered filtering. Through careful modeling of the carrier and the phase dynamics, we explain in detail the origin of sub-pulses in the wavelength converted output, with an emphasis on the time-resolved frequency chirping of the output signal. Through our simulations we conclude that the sub-pulses and the main-pulses are oppositely chirped, which is also verified experimentally by analyzing the output with a chirp form analyzer. We propose and demonstrate an optical off-center filtering technique which effectively suppresses these sub-pulses. The effects of filter detuning and phase bias adjustment in the delayed-interferometer are experimentally characterized and optimized, leading to a >3 dB extinction ratio enhancement of the output signal.

Broadband true time delay for microwave signal processing, using slow light based on stimulated Brillouin scattering in optical fibers.

Science.gov (United States)

Chin, Sanghoon; Thévenaz, Luc; Sancho, Juan; Sales, Salvador; Capmany, José; Berger, Perrine; Bourderionnet, Jérôme; Dolfi, Daniel

2010-10-11

We experimentally demonstrate a novel technique to process broadband microwave signals, using all-optically tunable true time delay in optical fibers. The configuration to achieve true time delay basically consists of two main stages: photonic RF phase shifter and slow light, based on stimulated Brillouin scattering in fibers. Dispersion properties of fibers are controlled, separately at optical carrier frequency and in the vicinity of microwave signal bandwidth. This way time delay induced within the signal bandwidth can be manipulated to correctly act as true time delay with a proper phase compensation introduced to the optical carrier. We completely analyzed the generated true time delay as a promising solution to feed phased array antenna for radar systems and to develop dynamically reconfigurable microwave photonic filters.

ROS mediates interferon gamma induced phosphorylation of Src, through the Raf/ERK pathway, in MCF-7 human breast cancer cell line.

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Zibara, Kazem; Zeidan, Asad; Bjeije, Hassan; Kassem, Nouhad; Badran, Bassam; El-Zein, Nabil

2017-03-01

Interferon gamma (IFN-ɣ) is a pleiotropic cytokine which plays dual contrasting roles in cancer. Although IFN-ɣ has been clinically used to treat various malignancies, it was recently shown to have protumorigenic activities. Reactive oxygen species (ROS) are overproduced in cancer cells, mainly due to NADPH oxidase activity, which results into several changes in signaling pathways. In this study, we examined IFN-ɣ effect on the phosphorylation levels of key signaling proteins, through ROS production, in the human breast cancer cell line MCF-7. After treatment by IFN-ɣ, results showed a significant increase in the phosphorylation of STAT1, Src, raf, AKT, ERK1/2 and p38 signaling molecules, in a time specific manner. Src and Raf were found to be involved in early stages of IFN-ɣ signaling since their phosphorylation increased very rapidly. Selective inhibition of Src-family kinases resulted in an immediate significant decrease in the phosphorylation status of Raf and ERK1/2, but not p38 and AKT. On the other hand, IFN-ɣ resulted in ROS generation, through H 2 O 2 production, whereas pre-treatment with the ROS inhibitor NAC caused ROS inhibition and a significant decrease in the phosphorylation levels of AKT, ERK1/2, p38 and STAT1. Moreover, pretreatment with a selective NOX1 inhibitor resulted in a significant decrease of AKT phosphorylation. Finally, no direct relationship was found between ROS production and calcium mobilization. In summary, IFN-ɣ signaling in MCF-7 cell line is ROS-dependent and follows the Src/Raf/ERK pathway whereas its signaling through the AKT pathway is highly dependent on NOX1.

Amplification of weak signals via the non-adiabatic regime of stochastic resonance in a bistable dynamical system with time delay

International Nuclear Information System (INIS)

Du Luchun; Mei Dongcheng

2011-01-01

The non-adiabatic regime of stochastic resonance (SR) in a bistable system with time delay, an additive white noise and a periodic signal was investigated. The signal power amplification η was employed to characterize the SR of the system. The simulation results indicate that (i) in the case of intermediate frequency Ω of the periodic signal, the typical behavior of SR is lowered monotonically by increasing the delay time τ; in the case of large Ω, τ weakens the SR behavior and then enhances it, with a non-monotonic behavior as a function of time delay; (ii) time delay induces SR when A is above the threshold, whereas no such resonance exists in the absence of time delay; (iii) time delay induces a transition from bimodal to unimodal configuration of η; (iv) varying the particular form of time delay results in different phenomena.

The Role of Reactive Oxygen Species (ROS in the Biological Activities of Metallic Nanoparticles

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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.

Elucidating hormonal/ROS networks during seed germination: insights and perspectives

DEFF Research Database (Denmark)

Diaz-Vivancos, Pedro; Barba Espin, Gregorio; Hernández, José Antonio

2013-01-01

” technologies together with physiological and biochemical approaches have revealed that seed germination is a very complex process that depends on multiple biochemical and molecular variables. The pivotal role of phytohormones in promoting germination now appears to be interdependent with ROS metabolism......While authors have traditionally emphasized the deleterious effects of reactive oxygen species (ROS) on seed biology, their role as signaling molecules during seed dormancy alleviation and germination is now the focus of many studies around the world. Over the last few years, studies using “-omics......, involving mitogen-activated protein kinase cascade activation, gene expression and post-translational protein modifications. This review is, thus, an attempt to summarize the new discoveries involving ROS and seed germination. The study of these interactions may supply markers of seed quality that might...

Reactive oxygen species signaling and stomatal movement: Current updates and future perspectives

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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.

Development of a methodology for analysis of delayed-neutron signals

International Nuclear Information System (INIS)

Gross, K.C.; Strain, R.V.; Fryer, R.M.

1980-02-01

Experimental and analytical techniques have been developed for analysis and characterization of delayed-neutron (DN) signals that can provide diagnostic information to augment data from cover-gas analyses in the detection and identification of breached elements in an LMFBR. Eleven flow-reduction tests have been run in EBR-II to provide base data support for predicting DN signal characteristics during exposed-fuel operation. Results from the tests demonstrate the feasibility and practicability of response-analysis techniques for determining (a) the transit time, T/sub tr/, for DN emitters traveling from the core to the detector and (b) the isotropic holdup time, T/sub h/, of DN precursors in the fuel element

Stanniocalcin-1 Protects a Mouse Model from Renal Ischemia-Reperfusion Injury by Affecting ROS-Mediated Multiple Signaling Pathways.

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Liu, Dajun; Shang, Huiping; Liu, Ying

2016-07-12

Stanniocalcin-1 (STC-1) protects against renal ischemia-reperfusion injury (RIRI). However, the molecular mechanisms remain widely unknown. STC-1 inhibits reactive oxygen species (ROS), whereas most ROS-mediated pathways are associated with ischemic injury. Therefore, to explore the mechanism, the effects of STC-1 on ROS-medicated pathways were studied. Non-traumatic vascular clamps were used to establish RIRI mouse models. The serum levels of STC-1, interleukin-6 (IL-6), interferon (IFN) γ, P53, and capase-3 were measured by ELISA kits. Superoxide dismutase (SOD) and malondialdehyde (MDA) were measured by fluorescence spectrofluorometer. All these molecules changed significantly in a RIRI model mouse when compared with those in a sham control. Kidney cells were isolated from sham and model mice. STC-1 was overexpressed or knockout in these kidney cells. The molecules in ROS-medicated pathways were measured by real-time quantitative PCR and Western blot. The results showed that STC-1 is an effective ROS scavenger. The serum levels of STC-1, MDA and SOD activity were increased while the serum levels of IL-6, iIFN-γ, P53, and capase-3 were decreased in a model group when compared with a sham control (p ROS-mediated molecules. Therefore, STC-1 maybe improve anti-inflammation, anti-oxidant and anti-apoptosis activities by affecting ROS-mediated pathways, especially the phospho-modifications of the respective proteins, resulting in the increase of SOD and reduce of capase-3, p53, IL-6 and IFN-γ.

Advanced glycation end products delay corneal epithelial wound healing through reactive oxygen species generation.

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Shi, Long; Chen, Hongmei; Yu, Xiaoming; Wu, Xinyi

2013-11-01

Delayed healing of corneal epithelial wounds is a serious complication in diabetes. Advanced glycation end products (AGEs) are intimately associated with the diabetic complications and are deleterious to the wound healing process. However, the effect of AGEs on corneal epithelial wound healing has not yet been evaluated. In the present study, we investigated the effect of AGE-modified bovine serum albumin (BSA) on corneal epithelial wound healing and its underlying mechanisms. Our data showed that AGE-BSA significantly increased the generation of intracellular ROS in telomerase-immortalized human corneal epithelial cells. However, the generation of intracellular ROS was completely inhibited by antioxidant N-acetylcysteine (NAC), anti-receptor of AGEs (RAGE) antibodies, or the inhibitor of NADPH oxidase. Moreover, AGE-BSA increased NADPH oxidase activity and protein expression of NADPH oxidase subunits, p22phox and Nox4, but anti-RAGE antibodies eliminated these effects. Furthermore, prevention of intracellular ROS generation using NAC or anti-RAGE antibodies rescued AGE-BSA-delayed epithelial wound healing in porcine corneal organ culture. In conclusion, our results demonstrated that AGE-BSA impaired corneal epithelial wound healing ex vivo. AGE-BSA increased intracellular ROS generation through NADPH oxidase activation, which accounted for the delayed corneal epithelial wound healing. These results may provide better insights for understanding the mechanism of delayed healing of corneal epithelial wounds in diabetes.

Fast realization of nonrecursive digital filters with limits on signal delay

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Titov, M. A.; Bondarenko, N. N.

1983-07-01

Attention is given to the problem of achieving a fast realization of nonrecursive digital filters with the aim of reducing signal delay. It is shown that a realization wherein the impulse characteristic of the filter is divided into blocks satisfies the delay requirements and is almost as economical in terms of the number of multiplications as conventional fast convolution. In addition, the block method leads to a reduction in the needed size of the memory and in the number of additions; the short-convolution procedure is substantially simplified. Finally, the block method facilitates the paralleling of computations owing to the simple transfers between subfilters.

Andrographolide, a Novel NF-κB Inhibitor, Induces Vascular Smooth Muscle Cell Apoptosis via a Ceramide-p47phox-ROS Signaling Cascade

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Yu-Ying Chen

2013-01-01

Full Text Available Atherosclerosis is linked with the development of many cardiovascular complications. Abnormal proliferation of vascular smooth muscle cells (VSMCs plays a crucial role in the development of atherosclerosis. Accordingly, the apoptosis of VSMCs, which occurs in the progression of vascular proliferation, may provide a beneficial strategy for managing cardiovascular diseases. Andrographolide, a novel nuclear factor-κB inhibitor, is the most active and critical constituent isolated from the leaves of Andrographis paniculata. Recent studies have indicated that andrographolide is a potential therapeutic agent for treating cancer through the induction of apoptosis. In this study, the apoptosis-inducing activity and mechanisms in andrographolide-treated rat VSMCs were characterized. Andrographolide significantly induced reactive oxygen species (ROS formation, p53 activation, Bax, and active caspase-3 expression, and these phenomena were suppressed by pretreating the cells with N-acetyl-L-cysteine, a ROS scavenger, or diphenylene iodonium, a nicotinamide adenine dinucleotide phosphate (NADPH oxidase (Nox inhibitor. Furthermore, p47phox, a Nox subunit protein, was phosphorylated in andrographolide-treated rat VSMCs. However, pretreatment with 3-O-methyl-sphingomyelin, a neutral sphingomyelinase inhibitor, significantly inhibited andrographolide-induced p47phox phosphorylation as well as Bax and active caspase-3 expression. Our results collectively demonstrate that andrographolide-reduced cell viability can be attributed to apoptosis in VSMCs, and this apoptosis-inducing activity was associated with the ceramide-p47phox-ROS signaling cascade.

JS-K promotes apoptosis by inducing ROS production in human prostate cancer cells.

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Qiu, Mingning; Chen, Lieqian; Tan, Guobin; Ke, Longzhi; Zhang, Sai; Chen, Hege; Liu, Jianjun

2017-03-01

Reactive oxygen species (ROS) are chemical species that alter redox status, and are responsible for inducing carcinogenesis. The purpose of the present study was to assess the effects of the glutathione S transferase-activated nitric oxide donor prodrug, JS-K, on ROS accumulation and on proliferation and apoptosis in human prostate cancer cells. Cell proliferation and apoptosis, ROS accumulation and the activation of the mitochondrial signaling pathway were measured. The results demonstrated that JS-K may inhibit prostate cancer cell growth in a dose- and time-dependent manner, and induce ROS accumulation and apoptosis in a dose-dependent manner. With increasing concentrations of JS-K, expression of pro-apoptotic proteins increased, but Bcl-2 expression decreased. Additionally, the antioxidant N-acetylcysteine reversed JS-K-induced cell apoptosis; conversely, the pro-oxidant glutathione disulfide exacerbated JS-K-induced apoptosis. In conclusion, the data suggest that JS-K induces prostate cancer cell apoptosis by increasing ROS levels.

Under fungal attack on a metalliferous soil: ROS or not ROS? Insights from Silene paradoxa L. growing under copper stress

International Nuclear Information System (INIS)

Taiti, Cosimo; Giorni, Elisabetta; Colzi, Ilaria; Pignattelli, Sara; Bazihizina, Nadia; Buccianti, Antonella; Luti, Simone; Pazzagli, Luigia; Mancuso, Stefano; Gonnelli, Cristina

2016-01-01

We investigated how the adaptation to metalliferous environments can influence the plant response to biotic stress. In a metallicolous and a non-metallicolous population of Silene paradoxa the induction of oxidative stress and the production of callose and volatiles were evaluated in the presence of copper and of the PAMP fungal protein cerato-platanin, separately and in combination. Our results showed incompatibility between the ordinary ROS-mediated response to fungal attack and the acquired mechanisms of preventing oxidative stress in the tolerant population. A similar situation was also demonstrated by the sensitive population growing in the presence of copper but, in this case, with a lack of certain responses, such as callose production. In addition, in terms of the joint behaviour of emitted volatiles, multivariate statistics showed that not only did the populations respond differently to the presence of copper or biotic stress, but also that the biotic and abiotic stresses interacted in different ways in the two populations. Our results demonstrated that the same incompatibility of hyperaccumulators in ROS-mediated biotic stress signals also seemed to be exhibited by the excluder metallophyte, but without the advantage of being able to rely on the elemental defence for plant protection from natural enemies. - Highlights: • Silene paradoxa plants from metalliferous and nonmetalliferous soil were studied. • Plants were exposed to Cerato-platanin in presence/absence of Cu in culture media. • ROS response was fully present in nonmetallicolous plants only in the absence of Cu. • Similar ROS response in metallicolous plants with or without Cu. - The adaptation to high concentrations of copper was found to interfere with the ordinary ROS-mediated response to fungal attack in an excluder metallophyte.

Caenorhabditis elegans as a model for understanding ROS function in physiology and disease

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Antonio Miranda-Vizuete

2017-04-01

Full Text Available ROS (reactive oxygen species are potentially damaging by-products of aerobic metabolism which, unchecked, can have detrimental effects on cell function. However, it is now widely accepted that, at physiological levels, certain ROS play important roles in cell signaling, acting as second messengers to regulate cell choices that contribute to the development, adaptation and survival of plants and animals. Despite important recent advances in the biochemical tools available to study redox-signaling, the molecular mechanisms underlying most of these responses remain poorly understood, particularly in multicellular organisms. As we will review here, C. elegans has emerged as a powerful animal model to elucidate these and other aspects of redox biology.

dq-Frame Cascaded Delayed Signal Cancellation-Based PLL

DEFF Research Database (Denmark)

Golestan, Saeed; Ramezani, Malek; Guerrero, Josep M.

2015-01-01

on their position in the PLL structure. Inspired from the concept of delayed signal cancellation (DSC), the idea of cascaded DSC (CDSC) has recently been introduced as an effective solution to improve the performance of the PLL under adverse grid conditions. However, the focus has been on the application of CDSC...... operator as the pre-filtering stage of PLL, and little work has been conducted on its application as the in-loop filtering stage of PLL. This paper provides a detailed analysis and design of dqCDSC-PLL (PLL with in-loop dq-frame CDSC operator). The study is started with an overview of this PLL...

Reactive oxygen species (ROS – a family of fate deciding molecules pivotal in constructive inflammation and wound healing

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N Bryan

2012-09-01

Full Text Available Wound healing requires a fine balance between the positive and deleterious effects of reactive oxygen species (ROS; a group of extremely potent molecules, rate limiting in successful tissue regeneration. A balanced ROS response will debride and disinfect a tissue and stimulate healthy tissue turnover; suppressed ROS will result in infection and an elevation in ROS will destroy otherwise healthy stromal tissue. Understanding and anticipating the ROS niche within a tissue will greatly enhance the potential to exogenously augment and manipulate healing.Tissue engineering solutions to augment successful healing and remodelling of wounded or diseased tissue rely on a controlled balance between the constructive and destructive capacity of the leukocyte secretome, including ROS.This review comprehensively considers leukocyte derived ROS in tissue repair with particular interest in surgical intervention with inclusion of a biomaterial. The article considers ROS fundamental chemistry, formation, stimulation and clearance before applying this to discuss the implications of ROS in healing tissue with and without a biomaterial. We also systematically discuss ROS in leukocyte signalling and compare and contrast experimental means of measuring ROS.

The interplay between autophagy and ROS in tumorigenesis

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Kongara, Sameera [Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ (United States); The Cancer Institute of New Jersey, New Brunswick, NJ (United States); Karantza, Vassiliki, E-mail: karantva@umdnj.edu [Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ (United States); The Cancer Institute of New Jersey, New Brunswick, NJ (United States); Division of Medical Oncology, Department of Internal Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ (United States)

2012-11-21

Reactive oxygen species (ROS) at physiological levels are important cell signaling molecules. However, aberrantly high ROS are intimately associated with disease and commonly observed in cancer. Mitochondria are primary sources of intracellular ROS, and their maintenance is essential to cellular health. Autophagy, an evolutionarily conserved process whereby cytoplasmic components are delivered to lysosomes for degradation, is responsible for mitochondrial turnover and removal of damaged mitochondria. Impaired autophagy is implicated in many pathological conditions, including neurological disorders, inflammatory bowel disease, diabetes, aging, and cancer. The first reports connecting autophagy to cancer showed that allelic loss of the essential autophagy gene BECLIN1 (BECN1) is prevalent in human breast, ovarian, and prostate cancers and that Becn1{sup +/-} mice develop mammary gland hyperplasias, lymphomas, lung and liver tumors. Subsequent studies demonstrated that Atg5{sup -/-} and Atg7{sup -/-} livers give rise to adenomas, Atg4C{sup -/-} mice are susceptible to chemical carcinogenesis, and Bif1{sup -/-} mice are prone to spontaneous tumors, indicating that autophagy defects promote tumorigenesis. Due to defective mitophagy, autophagy-deficient cells accumulate damaged mitochondria and deregulated ROS levels, which likely contribute to their tumor-initiating capacity. However, the role of autophagy in tumorigenesis is complex, as more recent work also revealed tumor dependence on autophagy: autophagy-competent mutant-Ras-expressing cells form tumors more efficiently than their autophagy-deficient counterparts; similarly, FIP200 deficiency suppresses PyMT-driven mammary tumorigenesis. These latter findings are attributed to the fact that tumors driven by powerful oncogenes have high metabolic demands catered to by autophagy. In this review, we discuss the relationship between ROS and autophagy and summarize our current knowledge on their functional interactions

The interplay between autophagy and ROS in tumorigenesis

International Nuclear Information System (INIS)

Kongara, Sameera; Karantza, Vassiliki

2012-01-01

Reactive oxygen species (ROS) at physiological levels are important cell signaling molecules. However, aberrantly high ROS are intimately associated with disease and commonly observed in cancer. Mitochondria are primary sources of intracellular ROS, and their maintenance is essential to cellular health. Autophagy, an evolutionarily conserved process whereby cytoplasmic components are delivered to lysosomes for degradation, is responsible for mitochondrial turnover and removal of damaged mitochondria. Impaired autophagy is implicated in many pathological conditions, including neurological disorders, inflammatory bowel disease, diabetes, aging, and cancer. The first reports connecting autophagy to cancer showed that allelic loss of the essential autophagy gene BECLIN1 (BECN1) is prevalent in human breast, ovarian, and prostate cancers and that Becn1 +/- mice develop mammary gland hyperplasias, lymphomas, lung and liver tumors. Subsequent studies demonstrated that Atg5 -/- and Atg7 -/- livers give rise to adenomas, Atg4C -/- mice are susceptible to chemical carcinogenesis, and Bif1 -/- mice are prone to spontaneous tumors, indicating that autophagy defects promote tumorigenesis. Due to defective mitophagy, autophagy-deficient cells accumulate damaged mitochondria and deregulated ROS levels, which likely contribute to their tumor-initiating capacity. However, the role of autophagy in tumorigenesis is complex, as more recent work also revealed tumor dependence on autophagy: autophagy-competent mutant-Ras-expressing cells form tumors more efficiently than their autophagy-deficient counterparts; similarly, FIP200 deficiency suppresses PyMT-driven mammary tumorigenesis. These latter findings are attributed to the fact that tumors driven by powerful oncogenes have high metabolic demands catered to by autophagy. In this review, we discuss the relationship between ROS and autophagy and summarize our current knowledge on their functional interactions in tumorigenesis.

Crosstalk between Rac1-mediated actin regulation and ROS production.

Science.gov (United States)

Acevedo, Alejandro; González-Billault, Christian

2018-02-20

The small RhoGTPase Rac1 is implicated in a variety of events related to actin cytoskeleton rearrangement. Remarkably, another event that is completely different from those related to actin regulation has the same relevance; the Rac1-mediated production of reactive oxygen species (ROS) through NADPH oxidases (NOX). Each outcome involves different Rac1 downstream effectors; on one hand, events related to the actin cytoskeleton require Rac1 to bind to WAVEs proteins and PAKs that ultimately promote actin branching and turnover, on the other, NOX-derived ROS production demands active Rac1 to be bound to a cytosolic activator of NOX. How Rac1-mediated signaling ends up promoting actin-related events, NOX-derived ROS, or both is poorly understood. Rac1 regulators, including scaffold proteins, are known to exert tight control over its functions. Hence, evidence of Rac1 regulatory events leading to both actin remodeling and NOX-mediated ROS generation are discussed. Moreover, cellular functions linked to physiological and pathological conditions that exhibit crosstalk between Rac1 outcomes are analyzed, while plausible roles in neuronal functions (and dysfunctions) are highlighted. Together, discussed evidence shed light on cellular mechanisms which requires Rac1 to direct either actin- and/or ROS-related events, helping to understand crucial roles of Rac1 dual functionality. Copyright © 2018 Elsevier Inc. All rights reserved.

DUOX enzyme activity promotes AKT signalling in prostate cancer cells.

Science.gov (United States)

Pettigrew, Christopher A; Clerkin, John S; Cotter, Thomas G

2012-12-01

Reactive oxygen species (ROS) and oxidative stress are related to tumour progression, and high levels of ROS have been observed in prostate tumours compared to normal prostate. ROS can positively influence AKT signalling and thereby promote cell survival. The aim of this project was to establish whether the ROS generated in prostate cancer cells positively regulate AKT signalling and enable resistance to apoptotic stimuli. In PC3 cells, dual oxidase (DUOX) enzymes actively generate ROS, which inactivate phosphatases, thereby maintaining AKT phosphorylation. Inhibition of DUOX by diphenylene iodium (DPI), intracellular calcium chelation and small-interfering RNA (siRNA) resulted in lower ROS levels, lower AKT and glycogen synthase kinase 3β (GSK3β) phosphorylation, as well as reduced cell viability and increased susceptibility to apoptosis stimulating fragment (FAS) induced apoptosis. This report shows that ROS levels in PC3 cells are constitutively maintained by DUOX enzymes, and these ROS positively regulate AKT signalling through inactivating phosphatases, leading to increased resistance to apoptosis.

Performance analysis of NOAA tropospheric signal delay model

International Nuclear Information System (INIS)

Ibrahim, Hassan E; El-Rabbany, Ahmed

2011-01-01

Tropospheric delay is one of the dominant global positioning system (GPS) errors, which degrades the positioning accuracy. Recent development in tropospheric modeling relies on implementation of more accurate numerical weather prediction (NWP) models. In North America one of the NWP-based tropospheric correction models is the NOAA Tropospheric Signal Delay Model (NOAATrop), which was developed by the US National Oceanic and Atmospheric Administration (NOAA). Because of its potential to improve the GPS positioning accuracy, the NOAATrop model became the focus of many researchers. In this paper, we analyzed the performance of the NOAATrop model and examined its effect on ionosphere-free-based precise point positioning (PPP) solution. We generated 3 year long tropospheric zenith total delay (ZTD) data series for the NOAATrop model, Hopfield model, and the International GNSS Services (IGS) final tropospheric correction product, respectively. These data sets were generated at ten IGS reference stations spanning Canada and the United States. We analyzed the NOAATrop ZTD data series and compared them with those of the Hopfield model. The IGS final tropospheric product was used as a reference. The analysis shows that the performance of the NOAATrop model is a function of both season (time of the year) and geographical location. However, its performance was superior to the Hopfield model in all cases. We further investigated the effect of implementing the NOAATrop model on the ionosphere-free-based PPP solution convergence and accuracy. It is shown that the use of the NOAATrop model improved the PPP solution convergence by 1%, 10% and 15% for the latitude, longitude and height components, respectively

Redox signaling during hypoxia in mammalian cells

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Kimberly A. Smith

2017-10-01

Full Text Available Hypoxia triggers a wide range of protective responses in mammalian cells, which are mediated through transcriptional and post-translational mechanisms. Redox signaling in cells by reactive oxygen species (ROS such as hydrogen peroxide (H2O2 occurs through the reversible oxidation of cysteine thiol groups, resulting in structural modifications that can change protein function profoundly. Mitochondria are an important source of ROS generation, and studies reveal that superoxide generation by the electron transport chain increases during hypoxia. Other sources of ROS, such as the NAD(PH oxidases, may also generate oxidant signals in hypoxia. This review considers the growing body of work indicating that increased ROS signals during hypoxia are responsible for regulating the activation of protective mechanisms in diverse cell types.

Po2 cycling protects diaphragm function during reoxygenation via ROS, Akt, ERK, and mitochondrial channels.

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Zuo, Li; Pannell, Benjamin K; Re, Anthony T; Best, Thomas M; Wagner, Peter D

2015-12-01

Po2 cycling, often referred to as intermittent hypoxia, involves exposing tissues to brief cycles of low oxygen environments immediately followed by hyperoxic conditions. After experiencing long-term hypoxia, muscle can be damaged during the subsequent reintroduction of oxygen, which leads to muscle dysfunction via reperfusion injury. The protective effect and mechanism behind Po2 cycling in skeletal muscle during reoxygenation have yet to be fully elucidated. We hypothesize that Po2 cycling effectively increases muscle fatigue resistance through reactive oxygen species (ROS), protein kinase B (Akt), extracellular signal-regulated kinase (ERK), and certain mitochondrial channels during reoxygenation. Using a dihydrofluorescein fluorescent probe, we detected the production of ROS in mouse diaphragmatic skeletal muscle in real time under confocal microscopy. Muscles treated with Po2 cycling displayed significantly attenuated ROS levels (n = 5; P ROS, Akt, ERK, as well as chemical stimulators to close mitochondrial ATP-sensitive potassium channel (KATP) or open mitochondrial permeability transition pore (mPTP). All these blockers or stimulators abolished improved muscle function with Po2 cycling treatment. This current investigation has discovered a correlation between KATP and mPTP and the Po2 cycling pathway in diaphragmatic skeletal muscle. Thus we have identified a unique signaling pathway that may involve ROS, Akt, ERK, and mitochondrial channels responsible for Po2 cycling protection during reoxygenation conditions in the diaphragm. Copyright © 2015 the American Physiological Society.

Brucein D, a Naturally Occurring Tetracyclic Triterpene Quassinoid, Induces Apoptosis in Pancreatic Cancer through ROS-Associated PI3K/Akt Signaling Pathway

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Zheng-Quan Lai

2017-12-01

Full Text Available Brucein D (BD, a major active quassinoid in Brucea javanica, has exhibited pronounced anticancer activities. However, the biologic mechanisms have not been fully explored. In this study, BD exhibited more potent cytotoxic effect on pancreatic cancer (PanCa cell lines, while exerted weaker cytotoxic effects on GES-1 cells (non-tumorigenic. BD was shown to elicit apoptosis through inducing both the intrinsic and extrinsic mitochondria-mediated caspase activations. Furthermore, the BD-induced apoptotic effects were dependent on the accumulated reactive oxygen species (ROS and inactivation of PI3K/Akt signaling pathway. Pretreatment with tempol completely prevented the cellular apoptosis induced by BD, and recovered the inactivation of AKT, which suggested ROS essentially involved in BD-elicited apoptosis and down-regulation of PI3K/Akt pathway. In addition, the results obtained from orthotopic xenograft in nude mice were congruent with those of the in vitro investigations. These results support the notion that BD held good potential to be further developed into an effective pharmaceutical agent for the treatment of PanCa.

Abstract and Effector-Selective Decision Signals Exhibit Qualitatively Distinct Dynamics before Delayed Perceptual Reports.

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Twomey, Deirdre M; Kelly, Simon P; O'Connell, Redmond G

2016-07-13

Electrophysiological research has isolated neural signatures of decision formation in a variety of brain regions. Studies in rodents and monkeys have focused primarily on effector-selective signals that translate the emerging decision into a specific motor plan, but, more recently, research on the human brain has identified an abstract signature of evidence accumulation that does not appear to play any direct role in action preparation. The functional dissociations between these distinct signal types have only begun to be characterized, and their dynamics during decisions with deferred actions with or without foreknowledge of stimulus-effector mapping, a commonly studied task scenario in single-unit and functional imaging investigations, have not been established. Here we traced the dynamics of distinct abstract and effector-selective decision signals in the form of the broad-band centro-parietal positivity (CPP) and limb-selective β-band (8-16 and 18-30 Hz) EEG activity, respectively, during delayed-reported motion direction decisions with and without foreknowledge of direction-response mapping. With foreknowledge, the CPP and β-band signals exhibited a similar gradual build-up following evidence onset, but whereas choice-predictive β-band activity persisted up until the delayed response, the CPP dropped toward baseline after peaking. Without foreknowledge, the CPP exhibited identical dynamics, whereas choice-selective β-band activity was eliminated. These findings highlight qualitative functional distinctions between effector-selective and abstract decision signals and are of relevance to the assumptions founding functional neuroimaging investigations of decision-making. Neural signatures of evidence accumulation have been isolated in numerous brain regions. Although animal neurophysiology has largely concentrated on effector-selective decision signals that translate the emerging decision into a specific motor plan, recent research on the human brain has

ROS-IGTL-Bridge: an open network interface for image-guided therapy using the ROS environment.

Science.gov (United States)

Frank, Tobias; Krieger, Axel; Leonard, Simon; Patel, Niravkumar A; Tokuda, Junichi

2017-08-01

With the growing interest in advanced image-guidance for surgical robot systems, rapid integration and testing of robotic devices and medical image computing software are becoming essential in the research and development. Maximizing the use of existing engineering resources built on widely accepted platforms in different fields, such as robot operating system (ROS) in robotics and 3D Slicer in medical image computing could simplify these tasks. We propose a new open network bridge interface integrated in ROS to ensure seamless cross-platform data sharing. A ROS node named ROS-IGTL-Bridge was implemented. It establishes a TCP/IP network connection between the ROS environment and external medical image computing software using the OpenIGTLink protocol. The node exports ROS messages to the external software over the network and vice versa simultaneously, allowing seamless and transparent data sharing between the ROS-based devices and the medical image computing platforms. Performance tests demonstrated that the bridge could stream transforms, strings, points, and images at 30 fps in both directions successfully. The data transfer latency was bridge could achieve 900 fps for transforms. Additionally, the bridge was demonstrated in two representative systems: a mock image-guided surgical robot setup consisting of 3D slicer, and Lego Mindstorms with ROS as a prototyping and educational platform for IGT research; and the smart tissue autonomous robot surgical setup with 3D Slicer. The study demonstrated that the bridge enabled cross-platform data sharing between ROS and medical image computing software. This will allow rapid and seamless integration of advanced image-based planning/navigation offered by the medical image computing software such as 3D Slicer into ROS-based surgical robot systems.

Two time-delay dynamic model on the transmission of malicious signals in wireless sensor network

International Nuclear Information System (INIS)

Keshri, Neha; Mishra, Bimal Kumar

2014-01-01

Highlights: • Role of time delay to reduce the adversary effect in WSN is explored. • Model with two time delays is proposed to analyse spread of malicious signal in WSN. • Dynamical behaviour of worm-free equilibrium and endemic equilibrium is shown. • Threshold condition for switch of stability are obtained analytically. • Relation between stability and the two time delays is also explored. - Abstract: Deployed in a hostile environment, motes of a Wireless sensor network (WSN) could be easily compromised by the attackers because of several constraints such as limited processing capabilities, memory space, and limited battery life time etc. While transmitting the data to their neighbour motes within the network, motes are easily compromised due to resource constraints. Here time delay can play an efficient role to reduce the adversary effect on motes. In this paper, we propose an epidemic model SEIR (Susceptible–Exposed–Infectious–Recovered) with two time delays to describe the transmission dynamics of malicious signals in wireless sensor network. The first delay accounts for an exposed (latent) period while the second delay is for the temporary immunity period due to multiple worm outbreaks. The dynamical behaviour of worm-free equilibrium and endemic equilibrium is shown from the point of stability which switches under some threshold condition specified by the basic reproduction number. Our results show that the global properties of equilibria also depends on the threshold condition and that latent and temporary immunity period in a mote does not affect the stability, but they play a positive role to control malicious attack. Moreover, numerical simulations are given to support the theoretical analysis

Non-thermal plasma induces mitochondria-mediated apoptotic signaling pathway via ROS generation in HeLa cells.

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Li, Wei; Yu, K N; Ma, Jie; Shen, Jie; Cheng, Cheng; Zhou, Fangjian; Cai, Zhiming; Han, Wei

2017-11-01

Non-thermal plasma (NTP) has been proposed as a novel therapeutic method for anticancer treatment. Although increasing evidence suggests that NTP selectively induces apoptosis in some types of tumor cells, the molecular mechanisms underlying this phenomenon remain unclear. In this study, we further investigated possible molecular mechanisms for NTP-induced apoptosis of HeLa cells. The results showed that NTP exposure significantly inhibited the growth and viability of HeLa cells. Morphological observation and flow cytometry analysis demonstrated that NTP exposure induced HeLa cell apoptosis. NTP exposure also activated caspase-9 and caspase-3, which subsequently cleaved poly (ADP- ribose) polymerase. Furthermore, NTP exposure suppressed Bcl-2 expression, enhanced Bax expression and translocation to mitochondria, activated mitochondria-mediated apoptotic pathway, followed by the release of cytochrome c. Further studies showed that NTP treatment led to ROS generation, whereas blockade of ROS generation by N-acetyl-l-cysteine (NAC, ROS scavengers) significantly prevented NTP-induced mitochondrial alteration and subsequent apoptosis of HeLa cells via suppressing Bax translocation, cytochrome c and caspase-3 activation. Taken together, our results indicated that NTP exposure induced mitochondria-mediated intrinsic apoptosis of HeLa cells was activated by ROS generation. These findings provide insights to the therapeutic potential and clinical research of NTP as a novel tool in cervical cancer treatment. Copyright © 2017. Published by Elsevier Inc.

Bystander signaling via oxidative metabolism.

Science.gov (United States)

Sawal, Humaira Aziz; Asghar, Kashif; Bureik, Matthias; Jalal, Nasir

2017-01-01

The radiation-induced bystander effect (RIBE) is the initiation of biological end points in cells (bystander cells) that are not directly traversed by an incident-radiation track, but are in close proximity to cells that are receiving the radiation. RIBE has been indicted of causing DNA damage via oxidative stress, besides causing direct damage, inducing tumorigenesis, producing micronuclei, and causing apoptosis. RIBE is regulated by signaling proteins that are either endogenous or secreted by cells as a means of communication between cells, and can activate intracellular or intercellular oxidative metabolism that can further trigger signaling pathways of inflammation. Bystander signals can pass through gap junctions in attached cell lines, while the suspended cell lines transmit these signals via hormones and soluble proteins. This review provides the background information on how reactive oxygen species (ROS) act as bystander signals. Although ROS have a very short half-life and have a nanometer-scale sphere of influence, the wide variety of ROS produced via various sources can exert a cumulative effect, not only in forming DNA adducts but also setting up signaling pathways of inflammation, apoptosis, cell-cycle arrest, aging, and even tumorigenesis. This review outlines the sources of the bystander effect linked to ROS in a cell, and provides methods of investigation for researchers who would like to pursue this field of science.

Pectins, ROS homeostasis and UV-B responses in plant roots.

Science.gov (United States)

Yokawa, Ken; Baluška, František

2015-04-01

Light from the sun contains far-red, visible and ultra violet (UV) wavelength regions. Almost all plant species have been evolved under the light environment. Interestingly, several photoreceptors, expressing both in shoots and roots, process the light information during the plant life cycle. Surprisingly, Arabidopsis root apices express besides the UVR8 UV-B receptor, also root-specific UV-B sensing proteins RUS1 and RUS2 linked to the polar cell-cell transport of auxin. In this mini-review, we focus on reactive oxygen species (ROS) signaling and possible roles of pectins internalized via endocytic vesicle recycling system in the root-specific UV-B perception and ROS homeostasis. Copyright © 2014 Elsevier Ltd. All rights reserved.

The path from mitochondrial ROS to aging runs through the mitochondrial permeability transition pore.

Science.gov (United States)

Rottenberg, Hagai; Hoek, Jan B

2017-10-01

Excessive production of mitochondrial reactive oxygen species (mROS) is strongly associated with mitochondrial and cellular oxidative damage, aging, and degenerative diseases. However, mROS also induces pathways of protection of mitochondria that slow aging, inhibit cell death, and increase lifespan. Recent studies show that the activation of the mitochondrial permeability transition pore (mPTP), which is triggered by mROS and mitochondrial calcium overloading, is enhanced in aged animals and humans and in aging-related degenerative diseases. mPTP opening initiates further production and release of mROS that damage both mitochondrial and nuclear DNA, proteins, and phospholipids, and also releases matrix NAD that is hydrolyzed in the intermembrane space, thus contributing to the depletion of cellular NAD that accelerates aging. Oxidative damage to calcium transporters leads to calcium overload and more frequent opening of mPTP. Because aging enhances the opening of the mPTP and mPTP opening accelerates aging, we suggest that mPTP opening drives the progression of aging. Activation of the mPTP is regulated, directly and indirectly, not only by the mitochondrial protection pathways that are induced by mROS, but also by pro-apoptotic signals that are induced by DNA damage. We suggest that the integration of these contrasting signals by the mPTP largely determines the rate of cell aging and the initiation of cell death, and thus animal lifespan. The suggestion that the control of mPTP activation is critical for the progression of aging can explain the conflicting and confusing evidence regarding the beneficial and deleterious effects of mROS on health and lifespan. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Ultrasound-targeted microbubble destruction enhances delayed BMC delivery and attenuates post-infarction cardiac remodelling by inducing engraftment signals.

Science.gov (United States)

Chen, Yanmei; Zhang, Chuanxi; Shen, Shuxin; Guo, Shengcun; Zhong, Lintao; Li, Xinzhong; Chen, Guojun; Chen, Gangbin; He, Xiang; Huang, Chixiong; He, Nvqin; Liao, Wangjun; Liao, Yulin; Bin, Jianping

2016-12-01

Delayed administration of bone marrow cells (BMCs) at 2-4 weeks after successful reperfusion in patients with acute myocardial infarction (MI) does not improve cardiac function. The reduction in engraftment signals observed following this time interval might impair the effects of delayed BMC treatment. In the present study, we aimed to determine whether ultrasound-targeted microbubble destruction (UTMD) treatment could increase engraftment signals, enhance the delivery of delayed BMCs and subsequently attenuate post-infarction cardiac remodelling. A myocardial ischaemia/reperfusion (I/R) model was induced in Wistar rats via left coronary ligation for 45 min followed by reperfusion. Western blotting revealed that engraftment signals peaked at 7 days post-I/R and were dramatically lower at 14 days post-I/R. The lower engraftment signals at 14 days post-I/R could be triggered by UTMD treatment at a mechanical index of 1.0-1.9. The troponin I levels in the 1.9 mechanical index group were higher than in the other groups. Simultaneous haematoxylin and eosin staining and fluorescence revealed that the number of engrafted BMCs in the ischaemic zone was greater in the group treated with both UTMD and delayed BMC transplantation than in the control groups (PBMC transplantation improved cardiac function and decreased cardiac fibrosis at 4 weeks after treatment, as compared with control groups (both PBMC transplantation increased capillary density, myocardial cell proliferation and c-kit + cell proliferation. These findings indicated that UTMD treatment could induce engraftment signals and enhance homing of delayed BMCs to ischaemic myocardium, attenuating post-infarction cardiac remodelling by promoting neovascularization, cardiomyogenesis and expansion of cardiac c-kit + cells. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

Baicalein Rescues Delayed Cooling via Preservation of Akt Activation and Akt-Mediated Phospholamban Phosphorylation

Directory of Open Access Journals (Sweden)

Zuohui Shao

2018-03-01

Full Text Available Cooling reduces the ischemia/reperfusion (I/R injury seen in sudden cardiac arrest (SCA by decreasing the burst of reactive oxygen species (ROS. Its cardioprotection is diminished when delay in reaching the target temperature occurs. Baicalein, a flavonoid derived from the root of Scutellaria baicalensis Georgi, possesses antioxidant properties. Therefore, we hypothesized that baicalein can rescue cooling cardioprotection when cooling is delayed. Two murine cardiomyocyte models, an I/R model (90 min ischemia/3 h reperfusion and stunning model (30 min ischemia/90 min reperfusion, were used to assess cell survival and contractility, respectively. Cooling (32 °C was initiated either during ischemia or during reperfusion. Cell viability and ROS generation were measured. Cell contractility was evaluated by real-time phase-contrast imaging. Our results showed that cooling reduced cell death and ROS generation, and this effect was diminished when cooling was delayed. Baicalein (25 µM, given either at the start of reperfusion or start of cooling, resulted in a comparable reduction of cell death and ROS production. Baicalein improved phospholamban phosphorylation, contractility recovery, and cell survival. These effects were Akt-dependent. In addition, no synergistic effect was observed with the combined treatments of cooling and baicalein. Our data suggest that baicalein may serve as a novel adjunct therapeutic strategy for SCA resuscitation.

Mycotoxin zearalenone induces AIF- and ROS-mediated cell death through p53- and MAPK-dependent signaling pathways in RAW264.7 macrophages.

Science.gov (United States)

Yu, Ji-Yeon; Zheng, Zhong-Hua; Son, Young-Ok; Shi, Xianglin; Jang, Young-Oh; Lee, Jeong-Chae

2011-12-01

Zearalenone (ZEN) is commonly found in many food commodities and is known to cause reproductive disorders and genotoxic effects. However, the mode of ZEN-induced cell death of macrophages and the mechanisms by which ZEN causes cytotoxicity remain unclear. The present study shows that ZEN treatment reduces viability of RAW264.7 cells in a dose-dependent manner. ZEN causes predominantly necrotic and late apoptotic cell death. ZEN treatment also results in the loss of mitochondrial membrane potential (MMP), mitochondrial changes in Bcl-2 and Bax proteins, and cytoplasmic release of cytochrome c and apoptosis-inducing factor (AIF). Pre-treatment of the cells with either z-VAD-fmk or z-IETD-fmk does not attenuate ZEN-mediated cell death, whereas catalase suppresses the ZEN-induced decrease in viability in RAW264.7 cells. Treating the cells with c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), or p53 inhibitor prevented ZEN-mediated changes, such as MMP loss, cellular reactive oxygen species (ROS) increase, and cell death. JNK or p38 MAPK inhibitor inhibited mitochondrial alterations of Bcl-2 and Bax proteins with attendant decreases in cellular ROS levels. Knockdown of AIF via siRNA transfection also diminished ZEN-induced cell death. Further, adenosine triphosphate was markedly depleted in the ZEN-exposed cells. Collectively, these results suggest that ZEN induces cytotoxicity in RAW264.7 cells via AIF- and ROS-mediated signaling, in which the activations of p53 and JNK/p38 play a key role. Copyright © 2011 Elsevier Ltd. All rights reserved.

Peroxiredoxin-controlled G-CSF signalling at the endoplasmic reticulum-early endosome interface

NARCIS (Netherlands)

K.K. Palande (Karishma); O. Roovers (Onno); J. Gits (Judith); C. Verwijmeren (Carola); Y. Iuchi (Yoshihito); J. Fujii (Junichi); B. Neel; R. Karisch (Robert); J. Tavernier; I.P. Touw (Ivo)

2011-01-01

textabstractReactive oxygen species (ROS) regulate growth factor receptor signalling at least in part by inhibiting oxidation-sensitive phosphatases. An emerging concept is that ROS act locally to affect signal transduction in different subcellular compartments and that ROS levels are regulated by

Small-Signal Analysis of the Microgrid Secondary Control Considering a Communication Time Delay

DEFF Research Database (Denmark)

Coelho, Ernane Antônio Alves; Wu, Dan; Guerrero, Josep M.

2016-01-01

This paper presents a small-signal analysis of an islanded microgrid composed of two or more voltage-source inverters connected in parallel. The primary control of each inverter is integrated through an internal current and voltage loops using proportional resonant compensators, a virtual impedance......, and an external power controller based on frequency and voltage droops. The frequency restoration function is implemented at the secondary control level, which executes a consensus algorithm that consists of a load-frequency control and a single time delay communication network. The consensus network consists...... the behavior of the system considering control parameters and time delay variation....

ROS generation and MAPKs activation contribute to the Ni-induced testosterone synthesis disturbance in rat Leydig cells.

Science.gov (United States)

Han, Aijie; Zou, Lingyue; Gan, Xiaoqin; Li, Yu; Liu, Fangfang; Chang, Xuhong; Zhang, Xiaotian; Tian, Minmin; Li, Sheng; Su, Li; Sun, Yingbiao

2018-06-15

Nickel (Ni) can disorder testosterone synthesis in rat Leydig cells, whereas the mechanisms remain unclear. The aim of this study was to investigate the role of reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) in Ni-induced disturbance of testosterone synthesis in rat Leydig cells. The testosterone production and ROS levels were detected in Leydig cells. The mRNA and protein levels of testosterone synthetase, including StAR, CYP11A1, 3β-HSD, CYP17A1 and 17β-HSD, were determined. Effects of Ni on the ERK1/2, p38 and JNK MAPKs were also investigated. The results showed that Ni triggered ROS generation, consequently resulted in the decrease of testosterone synthetase expression and testosterone production in Leydig cells, which were then attenuated by ROS scavengers of N-acetylcysteine (NAC) and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), indicating that ROS are involved in the Ni-induced testosterone biosynthesis disturbance. Meanwhile Ni activated the ERK1/2, p38 and JNK MAPKs. Furthermore, Ni-inhibited testosterone synthetase expression levels and testosterone secretion were all alleviated by co-treatment with MAPK specific inhibitors (U0126 and SB203580, respectively), implying that Ni inhibited testosterone synthesis through activating ERK1/2 and p38 MAPK signal pathways in Leydig cells. In conclusion, these findings suggest that Ni causes testosterone synthesis disorder, partly, via ROS and MAPK signal pathways. Copyright © 2018 Elsevier B.V. All rights reserved.

Stable transmission of radio frequency signals on fiber links using interferomectric delay sensing

International Nuclear Information System (INIS)

Wilcox, Russell B.; Byrd, J.M.; Doolittle, Lawrence; Huang, Gang; Staples, J.W.

2009-01-01

The authors demonstrate distribution of a 2850 MHz rf signal over stabilized optical fiber links. For a 2.2 km link they measure an rms drift of 19.4 fs over 60 h, and for a 200 m link an rms drift of 8.4 fs over 20 h. The rf signals are transmitted as amplitude modulation on a continuous optical carrier. Variations in the delay length are sensed using heterodyne interferometry and used to correct the rf phase. The system uses standard fiber telecommunications components.

Low concentrations of salicylic acid delay methyl jasmonate-induced leaf senescence by up-regulating nitric oxide synthase activity.

Science.gov (United States)

Ji, Yingbin; Liu, Jian; Xing, Da

2016-09-01

In plants, extensive efforts have been devoted to understanding the crosstalk between salicylic acid (SA) and jasmonic acid (JA) signaling in pathogen defenses, but this crosstalk has scarcely been addressed during senescence. In this study, the effect of SA application on methyl jasmonate (MeJA)-induced leaf senescence was assessed. We found that low concentrations of SA (1-50 μM) played a delayed role against the senescence promoted by MeJA. Furthermore, low concentrations of SA enhanced plant antioxidant defenses and restricted reactive oxygen species (ROS) accumulation in MeJA-treated leaves. When applied simultaneously with MeJA, low concentrations of SA triggered a nitric oxide (NO) burst, and the elevated NO levels were linked to the nitric oxide associated 1 (NOA1)-dependent pathway via nitric oxide synthase (NOS) activity. The ability of SA to up-regulate plant antioxidant defenses, reduce ROS accumulation, and suppress leaf senescence was lost in NO-deficient Atnoa1 plants. In a converse manner, exogenous addition of NO donors increased the plant antioxidant capacity and lowered the ROS levels in MeJA-treated leaves. Taken together, the results indicate that SA at low concentrations counteracts MeJA-induced leaf senescence through NOA1-dependent NO signaling and strengthening of the antioxidant defense. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The alternative Medicago truncatula defense proteome of ROS – defective transgenic roots during early microbial infection

Directory of Open Access Journals (Sweden)

Leonard Muriithi Kiirika

2014-07-01

Full Text Available ROP-type GTPases of plants function as molecular switches within elementary signal transduction pathways such as the regulation of ROS synthesis via activation of NADPH oxidases (RBOH-respiratory burst oxidase homologue in plants. Previously, we reported that silencing of the Medicago truncatula GTPase MtROP9 led to reduced ROS production and suppressed induction of ROS-related enzymes in transgenic roots (MtROP9i infected with pathogenic (Aphanomyces euteiches and symbiotic microorganisms (Glomus intraradices, Sinorhizobium meliloti. While fungal infections were enhanced, S. meliloti infection was drastically impaired. In this study, we investigate the temporal proteome response of M. truncatula MtROP9i transgenic roots during the same microbial interactions under conditions of deprived potential to synthesize ROS. In comparison with control roots (Mtvector, we present a comprehensive proteomic analysis using sensitive MS protein identification. For four early infection time-points (1, 3, 5, 24 hpi, 733 spots were found to be different in abundance: 213 spots comprising 984 proteins (607 unique were identified after S. meliloti infection, 230 spots comprising 796 proteins (580 unique after G. intraradices infection, and 290 spots comprising 1240 proteins (828 unique after A. euteiches infection. Data evaluation by GelMap in combination with a heatmap tool allowed recognition of key proteome changes during microbial interactions under conditions of hampered ROS synthesis. Overall, the number of induced proteins in MtROP9i was low as compared with controls, indicating a dual function of ROS in defense signaling as well as alternative response patterns activated during microbial infection. Qualitative analysis of induced proteins showed that enzymes linked to ROS production and scavenging were highly induced in control roots, while in MtROP9i the majority of proteins were involved in alternative defense pathways such as cell wall and protein

ROS Mediates Radiation-Induced Differentiation in Human Lung Fibroblast

International Nuclear Information System (INIS)

Park, Sa Rah; Ahn, Ji Yeon; Kim, Mi Hyeung; Lim, Min Jin; Yun, Yeon Sook; Song, Jie Young

2009-01-01

One of the most common tumors worldwide is lung cancer and the number of patients with lung cancer received radiotherapy is increasing rapidly. Although radiotherapy may have lots of advantages, it can also induce serious adverse effects such as acute radiation pneumonitis and pulmonary fibrosis. Pulmonary fibrosis is characterized by excessive production of smooth muscle actin-alpha (a-SMA) and accumulation of extracellular matrix (ECM) such as collagen and fibronectin. There has been a great amount of research about fibrosis but the exact mechanism causing the reaction is not elucidated especially in radiation-induced fibrosis. Until now it has been known that several factors such as transforming growth factor (TGF-b), tumor necrosis factor (TNF), IL-6, platelet-derived growth factor (PDGF) and reactive oxygen species are related to fibrosis. It is also reported that reactive oxygen species (ROS) can be induced by radiation and can act as a second messenger in various signaling pathways. Therefore we focused on the role of ROS in radiation induced fibrosis. Here, we suggest that irradiation generate ROS mainly through NOX4, result in differentiation of lung fibroblast into myofibroblast

Assessment of a Standardized ROS Production Profile in Humans by Electron Paramagnetic Resonance

Directory of Open Access Journals (Sweden)

Simona Mrakic-Sposta

2012-01-01

Full Text Available Despite the growing interest in the role of reactive oxygen species (ROS in health and disease, reliable quantitative noninvasive methods for the assessment of oxidative stress in humans are still lacking. EPR technique, coupled to a specific spin probe (CMH: 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine is here presented as the method of choice to gain a direct measurement of ROS in biological fluids and tissues. The study aimed at demonstrating that, differently from currently available “a posteriori” assays of ROS-induced damage by means of biomolecules (e.g., proteins and lipids spin-trapping EPR provides direct evidence of the “instantaneous” presence of radical species in the sample and, as signal areas are proportional to the number of excited electron spins, lead to absolute concentration levels. Using a recently developed bench top continuous wave system (e-scan EPR scanner, Bruker dealing with very low ROS concentration levels in small (50 μL samples, we successfully monitored rapid ROS production changes in peripheral blood of athletes after controlled exercise and sedentary subjects after antioxidant supplementation. The correlation between EPR results and data obtained by various enzymatic assays (e.g., protein carbonyls and thiobarbituric acid reactive substances was determined too. Synthetically, our method allows reliable, quick, noninvasive quantitative determination of ROS in human peripheral blood.

Bystander signaling via oxidative metabolism

Directory of Open Access Journals (Sweden)

Sawal HA

2017-08-01

Full Text Available Humaira Aziz Sawal,1 Kashif Asghar,2 Matthias Bureik,3 Nasir Jalal4 1Healthcare Biotechnology Department, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, 2Basic Sciences Research, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan; 3Health Science Platform, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China; 4Health Science Platform, Department of Molecular and Cellular Pharmacology, Tianjin University, Tianjin, China Abstract: The radiation-induced bystander effect (RIBE is the initiation of biological end points in cells (bystander cells that are not directly traversed by an incident-radiation track, but are in close proximity to cells that are receiving the radiation. RIBE has been indicted of causing DNA damage via oxidative stress, besides causing direct damage, inducing tumorigenesis, producing micronuclei, and causing apoptosis. RIBE is regulated by signaling proteins that are either endogenous or secreted by cells as a means of communication between cells, and can activate intracellular or intercellular oxidative metabolism that can further trigger signaling pathways of inflammation. Bystander signals can pass through gap junctions in attached cell lines, while the suspended cell lines transmit these signals via hormones and soluble proteins. This review provides the background information on how reactive oxygen species (ROS act as bystander signals. Although ROS have a very short half-life and have a nanometer-scale sphere of influence, the wide variety of ROS produced via various sources can exert a cumulative effect, not only in forming DNA adducts but also setting up signaling pathways of inflammation, apoptosis, cell-cycle arrest, aging, and even tumorigenesis. This review outlines the sources of the bystander effect linked to ROS in a cell, and provides methods of investigation for researchers who would like to

ROS (Robot Operating System) für Automotive

OpenAIRE

Bubeck, Alexander

2014-01-01

- Introduction into the Robot Operating System - Open Source in the automotive industries - Application of ROS in the automotive industry - ROS navigation - ROS with real time control - ROS in the embedded world - Outlook: ROS 2.0 - Summary

Crosstalk between mitochondrial stress signals regulates yeast chronological lifespan.

Science.gov (United States)

Schroeder, Elizabeth A; Shadel, Gerald S

2014-01-01

Mitochondrial DNA (mtDNA) exists in multiple copies per cell and is essential for oxidative phosphorylation. Depleted or mutated mtDNA promotes numerous human diseases and may contribute to aging. Reduced TORC1 signaling in the budding yeast, Saccharomyces cerevisiae, extends chronological lifespan (CLS) in part by generating a mitochondrial ROS (mtROS) signal that epigenetically alters nuclear gene expression. To address the potential requirement for mtDNA maintenance in this response, we analyzed strains lacking the mitochondrial base-excision repair enzyme Ntg1p. Extension of CLS by mtROS signaling and reduced TORC1 activity, but not caloric restriction, was abrogated in ntg1Δ strains that exhibited mtDNA depletion without defects in respiration. The DNA damage response (DDR) kinase Rad53p, which transduces pro-longevity mtROS signals, is also activated in ntg1Δ strains. Restoring mtDNA copy number alleviated Rad53p activation and re-established CLS extension following mtROS signaling, indicating that Rad53p senses mtDNA depletion directly. Finally, DDR kinases regulate nucleus-mitochondria localization dynamics of Ntg1p. From these results, we conclude that the DDR pathway senses and may regulate Ntg1p-dependent mtDNA stability. Furthermore, Rad53p senses multiple mitochondrial stresses in a hierarchical manner to elicit specific physiological outcomes, exemplified by mtDNA depletion overriding the ability of Rad53p to transduce an adaptive mtROS longevity signal. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Cadmium induces matrix metalloproteinase-9 expression via ROS-dependent EGFR, NF-kB, and AP-1 pathways in human endothelial cells

International Nuclear Information System (INIS)

Lian, Sen; Xia, Yong; Khoi, Pham Ngoc; Ung, Trong Thuan; Yoon, Hyun Joong; Kim, Nam Ho; Kim, Kyung Keun; Jung, Young Do

2015-01-01

Highlights: • Cadmium induces MMP-9 expression through NADPH oxidase-derived ROS. • Cadmium induces MMP-9 through EGFR-mediated Akt, Erk1/2 and JNK1/2 signaling pathways. • Akt, MAPKs (Erk1/2 and JNK1/2) functioned as upstream signals of NF-kB and AP-1 respectively, in cadmium-induced MMP-9 in endothelial cells. • ROS production by NADPH oxidase is the furthest upstream signal in MMP-9 expression in ECV304 cells. - Abstract: Cadmium (Cd), a widespread cumulative pollutant, is a known human carcinogen, associated with inflammation and tumors. Matrix metalloproteinase-9 (MMP-9) plays a pivotal role in tumor metastasis; however, the mechanisms underlying the MMP-9 expression induced by Cd remain obscure in human endothelial cells. Here, Cd elevated MMP-9 expression in dose- and time-dependent manners in human endothelial cells. Cd increased ROS production and the ROS-producing NADPH oxidase. Cd translocates p47 phox , a key subunit of NADPH oxidase, to the cell membrane. Cd also activated the phosphorylation of EGFR, Akt, Erk1/2, and JNK1/2 in addition to promoting NF-kB and AP-1 binding activities. Specific inhibitor and mutagenesis studies showed that EGFR, Akt, Erk1/2, JNK1/2 and transcription factors NF-κB and AP-1 were related to Cd-induced MMP-9 expression in endothelial cells. Akt, Erk1/2, and JNK1/2 functioned as upstream signals in the activation of NF-κB and AP-1, respectively. In addition, N-acetyl-L-cystein (NAC), diphenyleneiodonium chloride (DPI) and apocynin (APO) inhibited the Cd-induced activation of EGFR, Akt, Erk1/2, JNK1/2, and p38 MAPK, indicating that ROS production by NADPH oxidase is the furthest upstream signal in MMP-9 expression. At present, it states that Cd displayed marked invasiveness in ECV304 cells, which was partially abrogated by MMP-9 neutralizing antibodies. These results demonstrated that Cd induces MMP-9 expression via ROS-dependent EGFR- > Erk1/2, JNK1/2- > AP-1 and EGFR- > Akt- > NF-κB signaling pathways and, in turn

The DECMU: a digital device for delayed analysis of multi-frequency eddy current signals

International Nuclear Information System (INIS)

Pigeon, Michel.

1981-08-01

A delayed data analysis system has been realized by the CEA and Intercontrole for in-service inspection of steam generators of nuclear plants by multifrequency eddy current testing. This device allows, out of the plant, adjustment during switching of the probes, graph recording and analysis for defect signal qualification. The equipment contains an analog mixing device, as IC3FA multi-frequency appartus, but has in addition a memory allowing data cycling and signal isolation for adjustment or analysis [fr

Screening for ROS1 gene rearrangements in non-small cell lung cancers using immunohistochemistry with FISH confirmation is an effective method to identify this rare target

Science.gov (United States)

Selinger, Christina I; Li, Bob T; Pavlakis, Nick; Links, Matthew; Gill, Anthony J; Lee, Adrian; Clarke, Stephen; Tran, Thang N; Lum, Trina; Yip, Po Yee; Horvath, Lisa; Yu, Bing; Kohonen-Corish, Maija RJ; O’Toole, Sandra A; Cooper, Wendy A

2016-01-01

Aims To assess the prevalence of ROS1 rearrangements in a retrospective and prospective diagnostic Australian cohort and evaluate the effectiveness of immunohistochemical screening. Methods A retrospective cohort of 278 early stage lung adenocarcinomas and an additional 104 prospective NSCLC cases referred for routine molecular testing were evaluated. ROS1 immunohistochemistry (IHC) was performed (D4D6 clone, Cell Signaling Technology) on all cases as well as fluorescence in situ hybridisation (FISH) using the ZytoVision and Abbott Molecular ROS1 FISH probes, with ≥15% of cells with split signals considered positive for rearrangement. Results Eighty eight cases (32%) from the retrospective cohort showed staining by ROS1 IHC, and one case (0.4%) showed ROS1 rearrangement by FISH. Nineteen of the prospective diagnostic cases showed ROS1 IHC staining of which 12 (12%) cases were confirmed as ROS1 rearranged by FISH. There were no ROS1 rearranged cases that showed no expression of ROS1 with IHC. The ROS1 rearranged cases in the prospective cohort were all EGFR wildtype and ALK rearrangement negative. The sensitivity of ROS1 IHC in the retrospective cohort was 100% and specificity was 76%. Conclusions ROS1 rearrangements are rare events in lung adenocarcinomas. Selection of cases for ROS1 FISH testing, by excluding EGFR/ALK positive cases and use of IHC to screen for potentially positive cases can be used to enrich for the likelihood of a identifying a ROS1 rearranged lung cancer and prevent the need to undertake expensive and time consuming FISH testing in all cases. PMID:27599111

Augmented BMPRIA-mediated BMP signaling in cranial neural crest lineage leads to cleft palate formation and delayed tooth differentiation.

Directory of Open Access Journals (Sweden)

Lu Li

Full Text Available The importance of BMP receptor Ia (BMPRIa mediated signaling in the development of craniofacial organs, including the tooth and palate, has been well illuminated in several mouse models of loss of function, and by its mutations associated with juvenile polyposis syndrome and facial defects in humans. In this study, we took a gain-of-function approach to further address the role of BMPR-IA-mediated signaling in the mesenchymal compartment during tooth and palate development. We generated transgenic mice expressing a constitutively active form of BmprIa (caBmprIa in cranial neural crest (CNC cells that contributes to the dental and palatal mesenchyme. Mice bearing enhanced BMPRIa-mediated signaling in CNC cells exhibit complete cleft palate and delayed odontogenic differentiation. We showed that the cleft palate defect in the transgenic animals is attributed to an altered cell proliferation rate in the anterior palatal mesenchyme and to the delayed palatal elevation in the posterior portion associated with ectopic cartilage formation. Despite enhanced activity of BMP signaling in the dental mesenchyme, tooth development and patterning in transgenic mice appeared normal except delayed odontogenic differentiation. These data support the hypothesis that a finely tuned level of BMPRIa-mediated signaling is essential for normal palate and tooth development.

ROS Installation and Commissioning

CERN Multimedia

Gorini, B

The ATLAS Readout group (a sub-group of TDAQ) has now completed the installation and commissioning of all of the Readout System (ROS) units. Event data from ATLAS is initially handled by detector specific hardware and software, but following a Level 1 Accept the data passes from the detector specific Readout Drivers (RODs) to the ROS, the first stage of the central ATLAS DAQ. Within the final ATLAS TDAQ system the ROS stores the data and on request makes it available to the Level 2 Trigger (L2) processors and to the Event Builder (EB) as required. The ROS is implemented as a large number of PCs housing custom built cards (ROBINs) and running custom multi-threaded software. Each ROBIN card (shown below) contains buffer memories to store the data, plus a field programmable gate array ( FPGA ) and an embedded PowerPC processor for management of the memories and data requests, and is implemented as a 64-bit 66 MHz PCI card. Both the software and the ROBIN cards have been designed and developed by the Readout g...

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

LISA time-delay interferometry zero-signal solution: Geometrical properties

International Nuclear Information System (INIS)

Tinto, Massimo; Larson, Shane L.

2004-01-01

Time-delay interferometry (TDI) is the data processing technique needed for generating interferometric combinations of data measured by the multiple Doppler readouts available onboard the three Laser Interferometer Space Antenna (LISA) spacecraft. Within the space of all possible interferometric combinations TDI can generate, we have derived a specific combination that has zero response to the gravitational wave signal, and called it the zero-signal solution (ZSS). This is a two-parameter family of linear combinations of the generators of the TDI space, and its response to a gravitational wave becomes null when these two parameters coincide with the values of the angles of the source location in the sky. Remarkably, the ZSS does not rely on any assumptions about the gravitational waveform, and in fact it works for waveforms of any kind. Our approach is analogous to the data analysis method introduced by Guersel and Tinto in the context of networks of Earth-based, wideband, interferometric gravitational wave detectors observing in coincidence a gravitational wave burst. The ZSS should be regarded as an application of the Guersel and Tinto method to the LISA data

A Small Molecule Polyamine Oxidase Inhibitor Blocks Androgen-Induced Oxidative Stress and Delays Prostate Cancer Progression in the TRAMP Mouse Model

Science.gov (United States)

Basu, Hirak S.; Thompson, Todd A.; Church, Dawn R.; Clower, Cynthia C.; Mehraein-Ghomi, Farideh; Amlong, Corey A.; Martin, Christopher T.; Woster, Patrick M.; Lindstrom, Mary J.; Wilding, George

2009-01-01

High levels of reactive oxygen species (ROS) present in human prostate epithelia are an important etiological factor in prostate cancer (CaP) occurrence, recurrence and progression. Androgen induces ROS production in the prostate by a yet unknown mechanism. Here, to the best of our knowledge, we report for the first time that androgen induces an overexpression of spermidine/spermine N1-acetyltransferase (SSAT), the rate-limiting enzyme in the polyamine oxidation pathway. As prostatic epithelia produce a large excess of polyamines, the androgen-induced polyamine oxidation that produces H2O2 could be a major reason for the high ROS levels in the prostate epithelia. A small molecule polyamine oxidase inhibitor N,N'-butanedienyl butanediamine (MDL 72,527 or CPC-200) effectively blocks androgen-induced ROS production in human CaP cells as well as significantly delays CaP progression and death in animals developing spontaneous CaP. These data demonstrate that polyamine oxidation is not only a major pathway for ROS production in prostate, but inhibiting this pathway also successfully delays prostate cancer progression. PMID:19773450

Radiation-induced PKC signaling system in cultured rat hepatocytes

International Nuclear Information System (INIS)

Nakajima, Tetsuo; Yukawa, Osami

1998-01-01

Radiation effects on living organisms are mainly caused through reactive oxygen species (ROS) on living cells. It is known that ROS damages various membranes and the bio membranes play an important role in cellular signal transduction pathways. The effects of radiation on cellular signal transduction pathways in cultured rat hepatocytes have been studied

Anti-skeletal muscle atrophy effect of Oenothera odorata root extract via reactive oxygen species-dependent signaling pathways in cellular and mouse model.

Science.gov (United States)

Lee, Yong-Hyeon; Kim, Wan-Joong; Lee, Myung-Hun; Kim, Sun-Young; Seo, Dong-Hyun; Kim, Han-Sung; Gelinsky, Michael; Kim, Tack-Joong

2016-01-01

Skeletal muscle atrophy can be defined as a decrease of muscle volume caused by injury or lack of use. This condition is associated with reactive oxygen species (ROS), resulting in various muscular disorders. We acquired 2D and 3D images using micro-computed tomography in gastrocnemius and soleus muscles of sciatic-denervated mice. We confirmed that sciatic denervation-small animal model reduced muscle volume. However, the intraperitoneal injection of Oenothera odorata root extract (EVP) delayed muscle atrophy compared to a control group. We also investigated the mechanism of muscle atrophy's relationship with ROS. EVP suppressed expression of SOD1, and increased expression of HSP70, in both H2O2-treated C2C12 myoblasts and sciatic-denervated mice. Moreover, EVP regulated apoptotic signals, including caspase-3, Bax, Bcl-2, and ceramide. These results indicate that EVP has a positive effect on reducing the effect of ROS on muscle atrophy.

Delayed expression of SAGs correlates with longevity in CMS wheat plants compared to its fertile plants.

Science.gov (United States)

Semwal, Vimal Kumar; Singh, Bhupinder; Khanna-Chopra, Renu

2014-04-01

Reproductive sinks regulate monocarpic senescence in crop plants. Monocarpic senescence was studied in wheat fertile (cv. HW 2041) and its isonuclear cytoplasmic male sterile (CMS) line. CMS plants exhibited slower rate of senescence accompanied by longer green leaf area duration and slower deceleration in chlorophyll, protein content, PN and rubisco content coupled with lower protease activities than fertile (F) plants. CMS plants also exhibited lower ROS levels and less membrane damage than F plants. CMS plants maintained better antioxidant defense, less oxidative damage in chloroplast and higher transcript levels of both rbcL and rbcS genes during senescence than F plants. F plants exhibited early induction and higher expression of SAGs like serine and cysteine proteases, glutamine synthetases GS1 and GS2, WRKY53 transcription factor and decline in transcript levels of CAT1 and CAT2 genes than CMS plants. Hence, using genetically fertile and its CMS line of wheat it is confirmed that delayed senescence in the absence of reproductive sinks is linked with slower protein oxidation, rubisco degradation and delayed activation of SAGs. Better antioxidant defense in chloroplasts at later stages of senescence was able to mitigate the deleterious effects of ROS in CMS plants. We propose that delayed increase in ROS in cytoplasmic male sterile wheat plants resulted in delayed activation of WRKY53, SAGs and the associated biochemical changes than fertile plants.

Endothelial cell oxidative stress and signal transduction

Directory of Open Access Journals (Sweden)

ROCIO FONCEA

2000-01-01

Full Text Available Endothelial dysfunction (ED is an early event in atherosclerotic disease, preceding clinical manifestations and complications. Increased reactive oxygen species (ROS have been implicated as important mechanisms that contribute to ED, and ROS’s may function as intracellular messengers that modulate signaling pathways. Several intracellular signal events stimulated by ROS have been defined, including the identification of two members of the mitogen activated protein kinase family (ERK1/2 and big MAP kinase, BMK1, tyrosine kinases (Src and Syk and different isoenzymes of PKC as redox-sensitive kinases. ROS regulation of signal transduction components include the modification in the activity of transcriptional factors such as NFkB and others that result in changes in gene expression and modifications in cellular responses. In order to understand the intracellular mechanisms induced by ROS in endothelial cells (EC, we are studying the response of human umbilical cord vein endothelial cells to increased ROS generation by different pro-atherogenic stimuli. Our results show that Homocysteine (Hcy and oxidized LDL (oxLDL enhance the activity and expression of oxidative stress markers, such as NFkB and heme oxygenase 1. These results suggest that these pro-atherogenic stimuli increase oxidative stress in EC, and thus explain the loss of endothelial function associated with the atherogenic process

SMG-1 kinase attenuates mitochondrial ROS production but not cell respiration deficits during hyperoxia.

Science.gov (United States)

Resseguie, Emily A; Brookes, Paul S; O'Reilly, Michael A

Supplemental oxygen (hyperoxia) used to treat individuals in respiratory distress causes cell injury by enhancing the production of toxic reactive oxygen species (ROS) and inhibiting mitochondrial respiration. The suppressor of morphogenesis of genitalia (SMG-1) kinase is activated during hyperoxia and promotes cell survival by phosphorylating the tumor suppressor p53 on serine 15. Here, we investigate whether SMG-1 and p53 blunt this vicious cycle of progressive ROS production and decline in mitochondrial respiration seen during hyperoxia. Human lung adenocarcinoma A549 and H1299 or colon carcinoma HCT116 cells were depleted of SMG-1, UPF-1, or p53 using RNA interference, and then exposed to room air (21% oxygen) or hyperoxia (95% oxygen). Immunoblotting was used to evaluate protein expression; a Seahorse Bioanalyzer was used to assess cellular respiration; and flow cytometry was used to evaluate fluorescence intensity of cells stained with mitochondrial or redox sensitive dyes. Hyperoxia increased mitochondrial and cytoplasmic ROS and suppressed mitochondrial respiration without changing mitochondrial mass or membrane potential. Depletion of SMG-1 or its cofactor, UPF1, significantly enhanced hyperoxia-induced mitochondrial but not cytosolic ROS abundance. They did not affect mitochondrial mass, membrane potential, or hyperoxia-induced deficits in mitochondrial respiration. Genetic depletion of p53 in A549 cells and ablation of the p53 gene in H1299 or HCT116 cells revealed that SMG-1 influences mitochondrial ROS through activation of p53. Our findings show that hyperoxia does not promote a vicious cycle of progressive mitochondrial ROS and dysfunction because SMG-1-p53 signaling attenuates production of mitochondrial ROS without preserving respiration. This suggests antioxidant therapies that blunt ROS production during hyperoxia may not suffice to restore cellular respiration.

Human Mut T Homolog 1 (MTH1): a roadblock for the tumor-suppressive effects of oncogenic RAS-induced ROS.

Science.gov (United States)

Rai, Priyamvada

2012-01-01

Oncogenic RAS-induced reactive oxygen species (ROS) trigger barriers to cell transformation and cancer progression through tumor-suppressive responses such as cellular senescence or cell death. We have recently shown that oncogenic RAS-induced DNA damage and attendant premature senescence can be prevented by overexpressing human MutT Homolog 1 (MTH1), the major mammalian detoxifier of the oxidized DNA precursor, 8-oxo-dGTP. Paradoxically, RAS-induced ROS are also able to participate in tumor progression via transformative processes such as mitogenic signaling, the epithelial-mesenchymal transition (EMT), anoikis inhibition, and PI3K/Akt-mediated survival signaling. Here we provide a preliminary insight into the influence of MTH1 levels on the EMT phenotype and Akt activation in RAS-transformed HMLE breast epithelial cells. Within this context, we will discuss the implications of MTH1 upregulation in oncogenic RAS-sustaining cells as a beneficial adaptive change that inhibits ROS-mediated cell senescence and participates in the maintenance of ROS-associated tumor-promoting mechanisms. Accordingly, targeting MTH1 in RAS-transformed tumor cells will not only induce proliferative defects but also potentially enhance therapeutic cytotoxicity by shifting cellular response away from pro-survival mechanisms.

Luteolin inhibits Cr(VI)-induced malignant cell transformation of human lung epithelial cells by targeting ROS mediated multiple cell signaling pathways

Energy Technology Data Exchange (ETDEWEB)

Pratheeshkumar, Poyil; Son, Young-Ok; Divya, Sasidharan Padmaja; Roy, Ram Vinod; Hitron, John Andrew; Wang, Lei [Center for Research on Environmental Disease, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States); Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States); Kim, Donghern; Dai, Jin [Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States); Asha, Padmaja [National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Cochin (India); Zhang, Zhuo [Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States); Wang, Yitao [State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau (China); Shi, Xianglin, E-mail: xshi5@email.uky.edu [Center for Research on Environmental Disease, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States); Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY 40536 (United States)

2014-12-01

Hexavalent chromium [Cr(VI)] is a well-known human carcinogen associated with the incidence of lung cancer. Inhibition of metal induced carcinogenesis by a dietary antioxidant is a novel approach. Luteolin, a natural dietary flavonoid found in fruits and vegetables, possesses potent antioxidant and anti-inflammatory activity. We found that short term exposure of human bronchial epithelial cells (BEAS-2B) to Cr(VI) (5 μM) showed a drastic increase in ROS generation, NADPH oxidase (NOX) activation, lipid peroxidation, and glutathione depletion, which were significantly inhibited by the treatment with luteolin in a dose dependent manner. Treatment with luteolin decreased AP-1, HIF-1α, COX-2, and iNOS promoter activity induced by Cr(VI) in BEAS-2B cells. In addition, luteolin protected BEAS-2B cells from malignant transformation induced by chronic Cr(VI) exposure. Moreover, luteolin also inhibited the production of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, TNF-α) and VEGF in chronic Cr(VI) exposed BEAS-2B cells. Western blot analysis showed that luteolin inhibited multiple gene products linked to survival (Akt, Fak, Bcl-2, Bcl-xL), inflammation (MAPK, NF-κB, COX-2, STAT-3, iNOS, TNF-α) and angiogenesis (HIF-1α, VEGF, MMP-9) in chronic Cr(VI) exposed BEAS-2B cells. Nude mice injected with BEAS-2B cells chronically exposed to Cr(VI) in the presence of luteolin showed reduced tumor incidence compared to Cr(VI) alone treated group. Overexpression of catalase (CAT) or SOD2, eliminated Cr(VI)-induced malignant transformation. Overall, our results indicate that luteolin protects BEAS-2B cells from Cr(VI)-induced carcinogenesis by scavenging ROS and modulating multiple cell signaling mechanisms that are linked to ROS. Luteolin, therefore, serves as a potential chemopreventive agent against Cr(VI)-induced carcinogenesis. - Highlights: • Luteolin inhibited Cr(VI)-induced oxidative stress. • Luteolin inhibited chronic Cr(VI)-induced malignant transformation. �

Luteolin inhibits Cr(VI)-induced malignant cell transformation of human lung epithelial cells by targeting ROS mediated multiple cell signaling pathways

International Nuclear Information System (INIS)

Pratheeshkumar, Poyil; Son, Young-Ok; Divya, Sasidharan Padmaja; Roy, Ram Vinod; Hitron, John Andrew; Wang, Lei; Kim, Donghern; Dai, Jin; Asha, Padmaja; Zhang, Zhuo; Wang, Yitao; Shi, Xianglin

2014-01-01

Hexavalent chromium [Cr(VI)] is a well-known human carcinogen associated with the incidence of lung cancer. Inhibition of metal induced carcinogenesis by a dietary antioxidant is a novel approach. Luteolin, a natural dietary flavonoid found in fruits and vegetables, possesses potent antioxidant and anti-inflammatory activity. We found that short term exposure of human bronchial epithelial cells (BEAS-2B) to Cr(VI) (5 μM) showed a drastic increase in ROS generation, NADPH oxidase (NOX) activation, lipid peroxidation, and glutathione depletion, which were significantly inhibited by the treatment with luteolin in a dose dependent manner. Treatment with luteolin decreased AP-1, HIF-1α, COX-2, and iNOS promoter activity induced by Cr(VI) in BEAS-2B cells. In addition, luteolin protected BEAS-2B cells from malignant transformation induced by chronic Cr(VI) exposure. Moreover, luteolin also inhibited the production of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, TNF-α) and VEGF in chronic Cr(VI) exposed BEAS-2B cells. Western blot analysis showed that luteolin inhibited multiple gene products linked to survival (Akt, Fak, Bcl-2, Bcl-xL), inflammation (MAPK, NF-κB, COX-2, STAT-3, iNOS, TNF-α) and angiogenesis (HIF-1α, VEGF, MMP-9) in chronic Cr(VI) exposed BEAS-2B cells. Nude mice injected with BEAS-2B cells chronically exposed to Cr(VI) in the presence of luteolin showed reduced tumor incidence compared to Cr(VI) alone treated group. Overexpression of catalase (CAT) or SOD2, eliminated Cr(VI)-induced malignant transformation. Overall, our results indicate that luteolin protects BEAS-2B cells from Cr(VI)-induced carcinogenesis by scavenging ROS and modulating multiple cell signaling mechanisms that are linked to ROS. Luteolin, therefore, serves as a potential chemopreventive agent against Cr(VI)-induced carcinogenesis. - Highlights: • Luteolin inhibited Cr(VI)-induced oxidative stress. • Luteolin inhibited chronic Cr(VI)-induced malignant transformation. �

The ROS Workshop

CERN Multimedia

Francis, D.

The first week of February saw the taking place of the ReadOut Subsystem (ROS) workshop. The ROS is the subsystem of the Trigger, DAQ & DCS project which receives and buffers data from the detector ReadOut Drivers (RODs). On request it then provides a subset of this buffered data, the so-called Regions of Interest (RoI), to the Level 2 trigger. Using the subsequent Level 2 trigger decision, the ROS either removes the buffered event data from its buffers or sends the full event data to the Event Filter for further processing. The workshop took place over a four-day period at a location in the Jura. The average daily attendance was twenty people, which mainly represented the five main ATLAS institutes currently engaged in this Trigger, DAQ & DCS activity. The aim of the workshop was to bring to an end the current prototyping activities in this area and launch the next, final, phase of prototyping. This new phase of prototyping will build on the successful activities of the previous phase and will focus...

Learning ROS for robotics programming

CERN Document Server

Martinez, Aaron

2013-01-01

The book will take an easy-to-follow and engaging tutorial approach, providing a practical and comprehensive way to learn ROS.If you are a robotic enthusiast who wants to learn how to build and program your own robots in an easy-to-develop, maintainable and shareable way, ""Learning ROS for Robotics Programming"" is for you. In order to make the most of the book, you should have some C++ programming background, knowledge of GNU/Linux systems, and computer science in general. No previous background on ROS is required, since this book provides all the skills required. It is also advisable to hav

Celecoxib alleviates tamoxifen-instigated angiogenic effects by ROS-dependent VEGF/VEGFR2 autocrine signaling

International Nuclear Information System (INIS)

Kumar, B N Prashanth; Rajput, Shashi; Dey, Kaushik Kumar; Parekh, Aditya; Das, Subhasis; Mazumdar, Abhijit; Mandal, Mahitosh

2013-01-01

Tamoxifen (TAM) is widely used in the chemotherapy of breast cancer and as a preventive agent against recurrence after surgery. However, extended TAM administration for breast cancer induces increased VEGF levels in patients, promoting new blood vessel formation and thereby limiting its efficacy. Celecoxib (CXB), a selective COX-2 inhibitor, suppresses VEGF gene expression by targeting the VEGF promoter responsible for its inhibitory effect. For this study, we had selected CXB as non-steroidal anti-inflammatory drug in combination with TAM for suppressing VEGF expression and simultaneously reducing doses of both the drugs. The effects of CXB combined with TAM were examined in two human breast cancer cell lines in culture, MCF7 and MDA-MB-231. Assays of proliferation, apoptosis, angiogenesis, metastasis, cell cycle distribution, and receptor signaling were performed. Here, we elucidated how the combination of TAM and CXB at nontoxic doses exerts anti-angiogenic effects by specifically targeting VEGF/VEGFR2 autocrine signaling through ROS generation. At the molecular level, TAM-CXB suppresses VHL-mediated HIF-1α activation, responsible for expression of COX-2, MMP-2 and VEGF. Besides low VEGF levels, TAM-CXB also suppresses VEGFR2 expression, confirmed through quantifying secreted VEGF levels, luciferase and RT-PCR studies. Interestingly, we observed that TAM-CXB was effective in blocking VEGFR2 promoter induced expression and further 2 fold decrease in VEGF levels was observed in combination than TAM alone in both cell lines. Secondly, TAM-CXB regulated VEGFR2 inhibits Src expression, responsible for tumor progression and metastasis. FACS and in vivo enzymatic studies showed significant increase in the reactive oxygen species upon TAM-CXB treatment. Taken together, our experimental results indicate that this additive combination shows promising outcome in anti-metastatic and apoptotic studies. In a line, our preclinical studies evidenced that this additive

Analysis of subpulse generation from delayed-interference signal-wavelength converter for wide carrier recovery rate range

DEFF Research Database (Denmark)

Sakaguchi, J.; Nielsen, Mads Lønstrup; Ohira, T.

2008-01-01

The generation of subpulses in delayed-interference signal-wavelength converters (DISCS) had been suspected as a Curse of waveform degradation in their application in ultrafast (similar to 160GHz) optical time division multiplexing (OTDM) communication systems. We reported its first observation...

UWB delay and multiply receiver

Energy Technology Data Exchange (ETDEWEB)

Dallum, Gregory E.; Pratt, Garth C.; Haugen, Peter C.; Romero, Carlos E.

2013-09-10

An ultra-wideband (UWB) delay and multiply receiver is formed of a receive antenna; a variable gain attenuator connected to the receive antenna; a signal splitter connected to the variable gain attenuator; a multiplier having one input connected to an undelayed signal from the signal splitter and another input connected to a delayed signal from the signal splitter, the delay between the splitter signals being equal to the spacing between pulses from a transmitter whose pulses are being received by the receive antenna; a peak detection circuit connected to the output of the multiplier and connected to the variable gain attenuator to control the variable gain attenuator to maintain a constant amplitude output from the multiplier; and a digital output circuit connected to the output of the multiplier.

ROS and CDPK-like kinase-mediated activation of MAP kinase in rice roots exposed to lead.

Science.gov (United States)

Huang, Tsai-Lien; Huang, Hao-Jen

2008-04-01

Lead (Pb2+) is a cytotoxic metal ion in plants, the mechanism of which is not yet established. The aim of this study is to investigate the signalling pathways that are activated by elevated concentrations of Pb2+ in rice roots. Root growth was stunted and cell death was accelerated when exposed to different dosages of Pb2+ during extended time periods. Using ROS-sensitive dye and Ca2+ indicator, we demonstrated that Pb2+ induced ROS production and Ca2+ accumulation, respectively. In addition, Pb2+ elicited a remarkable increase in myelin basic protein (MBP) kinase activities. By immunoblot and immunoprecipitation analysis, 40- and 42-kDa MBP kinases that were activated by Pb2+ were identified to be mitogen-activated protein (MAP) kinases. Pre-treatment of rice roots with an antioxidant and a NADPH oxidase inhibitor, glutathione (GSH) and diphenylene iodonium (DPI), effectively reduced Pb2+-induced cell death and MAP kinase activation. Moreover, calcium-dependent protein kinase (CDPK) antagonist, W7, attenuated Pb2+-induced cell death and MAP kinase activation. These results suggested that the ROS and CDPK may function in the Pb2+-triggered cell death and MAP kinase signalling pathway in rice roots.

Crizotinib-Resistant ROS1 Mutations Reveal a Predictive Kinase Inhibitor Sensitivity Model for ROS1- and ALK-Rearranged Lung Cancers.

Science.gov (United States)

Facchinetti, Francesco; Loriot, Yohann; Kuo, Mei-Shiue; Mahjoubi, Linda; Lacroix, Ludovic; Planchard, David; Besse, Benjamin; Farace, Françoise; Auger, Nathalie; Remon, Jordi; Scoazec, Jean-Yves; André, Fabrice; Soria, Jean-Charles; Friboulet, Luc

2016-12-15

The identification of molecular mechanisms conferring resistance to tyrosine kinase inhibitor (TKI) is a key step to improve therapeutic results for patients with oncogene addiction. Several alterations leading to EGFR and anaplastic lymphoma kinase (ALK) resistance to TKI therapy have been described in non-small cell lung cancer (NSCLC). Only two mutations in the ROS1 kinase domain responsible for crizotinib resistance have been described in patients thus far. A patient suffering from a metastatic NSCLC harboring an ezrin (EZR)-ROS1 fusion gene developed acquired resistance to the ALK/ROS1 inhibitor crizotinib. Molecular analysis (whole-exome sequencing, CGH) and functional studies were undertaken to elucidate the mechanism of resistance. Based on this case, we took advantage of the structural homology of ROS1 and ALK to build a predictive model for drug sensitivity regarding future ROS1 mutations. Sequencing revealed a dual mutation, S1986Y and S1986F, in the ROS1 kinase domain. Functional in vitro studies demonstrated that ROS1 harboring either the S1986Y or the S1986F mutation, while conferring resistance to crizotinib and ceritinib, was inhibited by lorlatinib (PF-06463922). The patient's clinical response confirmed the potency of lorlatinib against S1986Y/F mutations. The ROS1 S1986Y/F and ALK C1156Y mutations are homologous and displayed similar sensitivity patterns to ALK/ROS1 TKIs. We extended this analogy to build a model predicting TKI efficacy against potential ROS1 mutations. Clinical evidence, in vitro validation, and homology-based prediction provide guidance for treatment decision making for patients with ROS1-rearranged NSCLC who progressed on crizotinib. Clin Cancer Res; 22(24); 5983-91. ©2016 AACR. ©2016 American Association for Cancer Research.

Chelerythrine induced cell death through ROS-dependent ER stress in human prostate cancer cells

Directory of Open Access Journals (Sweden)

Wu S

2018-05-01

Full Text Available Songjiang Wu, Yanying Yang, Feiping Li, Lifu Huang, Zihua Han, Guanfu Wang, Hongyuan Yu, Haiping Li Department of Urology, Enze Hospital of Taizhou Enze Medical Center (Group, Taizhou, China Introduction: Prostate cancer is the most common noncutaneous cancer and the second leading cause of cancer-related mortality worldwide and the third in USA in 2017. Chelerythrine (CHE, a naturalbenzo[c]phenanthridine alkaloid, formerly identified as a protein kinase C inhibitor, has also shown anticancer effect through a number of mechanisms. Herein, effect and mechanism of the CHE-induced apoptosis via reactive oxygen species (ROS-mediated endoplasmic reticulum (ER stress in prostate cancer cells were studied for the first time. Methods: In our present study, we investigated whether CHE induced cell viability decrease, colony formation inhibition, and apoptosis in a dose-dependent manner in PC-3 cells. In addition, we showed that CHE increases intracellular ROS and leads to ROS-dependent ER stress and cell apoptosis. Results: Pre-treatment with N-acetyl cysteine, an ROS scavenger, totally reversed the CHE-induced cancer cell apoptosis as well as ER stress activation, suggesting that the ROS generation was responsible for the anticancer effects of CHE. Conclusion: Taken together, our findings support one of the anticancer mechanisms by which CHE increased ROS accumulation in prostate cancer cells, thereby leading to ER stress and caused intrinsic apoptotic signaling. The study reveals that CHE could be a potential candidate for application in the treatment of prostate cancer. Keywords: chelerythrine, reactive oxygen species, endoplasmic reticulum stress, apoptosis, prostate cancer

Mitochondrial ROS Production Protects the Intestine from Inflammation through Functional M2 Macrophage Polarization

Directory of Open Access Journals (Sweden)

Laura Formentini

2017-05-01

Full Text Available Mitochondria are signaling hubs in cellular physiology that play a role in inflammatory diseases. We found that partial inhibition of the mitochondrial ATP synthase in the intestine of transgenic mice triggers an anti-inflammatory response through NFκB activation mediated by mitochondrial mtROS. This shielding phenotype is revealed when mice are challenged by DSS-induced colitis, which, in control animals, triggers inflammation, recruitment of M1 pro-inflammatory macrophages, and the activation of the pro-oncogenic STAT3 and Akt/mTOR pathways. In contrast, transgenic mice can polarize macrophages to the M2 anti-inflammatory phenotype. Using the mitochondria-targeted antioxidant MitoQ to quench mtROS in vivo, we observe decreased NFκB activation, preventing its cellular protective effects. These findings stress the relevance of mitochondrial signaling to the innate immune system and emphasize the potential role of the ATP synthase as a therapeutic target in inflammatory and other related diseases.

Autophagy Inhibition Contributes to ROS-Producing NLRP3-Dependent Inflammasome Activation and Cytokine Secretion in High Glucose-Induced Macrophages.

Science.gov (United States)

Dai, Jiezhi; Zhang, Xiaotian; Li, Li; Chen, Hua; Chai, Yimin

2017-01-01

Type 2 diabetes is a persistent inflammatory response that impairs the healing process. We hypothesized that stimulation with high glucose following a pro-inflammatory signal would lead to autophagy inhibition, reactive oxygen species (ROS) production and eventually to the activation of the Nod-like receptor protein (NLRP) -3. Macrophages were isolated from human diabetic wound. We measured the expression of NLRP3, caspase1 and interleukin-1 beta (IL-1β) by western blot and real-time PCR, and the surface markers on cells by flow cytometry. THP-1-derived macrophages exposed to high glucose were applied to study the link between autophagy, ROS and NLRP3 activation. LC3-II, P62, NLRP3 inflammation and IL-1β expression were measured by western blot and real-time PCR. ROS production was measured with a Cellular Reactive Oxygen Species Detection Assay Kit. Macrophages isolated from diabetic wounds exhibited a pro-inflammatory phenotype, including sustained NLRP3 inflammasome activity associated with IL-1β secretion. Our data showed that high glucose inhibited autophagy, induced ROS production, and activated NLRP3 inflammasome and cytokine secretion in THP-1-derived macrophages. To study high glucose-induced NLRP3 inflammasome signalling, we performed studies using an autophagy inducer, a ROS inhibitor and a NLRP3 inhibitor and found that all reduced the NLRP3 inflammasome activation and cytokine secretion. Sustained NLRP3 inflammasome activity in wound-derived macrophages contributes to the hyper-inflammation in human diabetic wounds. Autophagy inhibition and ROS generation play an essential role in high glucose-induced NLRP3 inflammasome activation and cytokine secretion in macrophages. © 2017 The Author(s). Published by S. Karger AG, Basel.

Synchronization of delayed systems in the presence of delay time modulation

International Nuclear Information System (INIS)

Kye, Won-Ho; Choi, Muhan; Kim, Myung-Woon; Lee, Soo-Young; Rim, Sunghwan; Kim, Chil-Min; Park, Young-Jai

2004-01-01

We investigate synchronization in the presence of delay time modulation for application to communication. We have observed that the robust synchronization is established by a common delay signal and its threshold is presented using Lyapunov exponents analysis. The influence of the delay time modulation in chaotic oscillators is also discussed

Tunicamycin promotes apoptosis in leukemia cells through ROS generation and downregulation of survivin expression.

Science.gov (United States)

Lim, Eun Jin; Heo, Jeonghoon; Kim, Young-Ho

2015-08-01

Tunicamycin (TN), one of the endoplasmic reticulum stress inducers, has been reported to inhibit tumor cell growth and exhibit anticarcinogenic activity. However, the mechanism by which TN initiates apoptosis remains poorly understood. In the present study, we investigated the effect of TN on the apoptotic pathway in U937 cells. We show that TN induces apoptosis in association with caspase-3 activation, generation of reactive oxygen species (ROS), and downregulation of survivin expression. P38 MAPK (mitogen-activated protein kinase) and the generation of ROS signaling pathway play crucial roles in TN-induced apoptosis in U937 cells. We hypothesized that TN-induced activation of p38 MAPK signaling pathway is responsible for cell death. To test this hypothesis, we selectively inhibited MAPK during treatment with TN. Our data demonstrated that inhibitor of p38 (SB), but not ERK (PD) or JNK (SP), partially maintained apoptosis during treatment with TN. Pre-treatment with NAC and GSH markedly prevented cell death, suggesting a role for ROS in this process. Ectopic expression of survivin in U937 cells attenuated TN-induced apoptosis by suppression of caspase-3 cleavage, mitochondrial membrane potential, and cytochrome c release in U937 cells. Taken together, our results show that TN modulates multiple components of the apoptotic response of human leukemia cells and raise the possibility of a novel therapeutic strategy for hematological malignancies.

Arctigenin induces apoptosis in colon cancer cells through ROS/p38MAPK pathway.

Science.gov (United States)

Li, Qing-chun; Liang, Yun; Tian, Yuan; Hu, Guang-rui

2016-01-01

In the current study the antiproliferative effect of arctigenin, plant lignin, was evaluated on human colon cancer cell line HT-29. Furthermore, attempts were made to explore the signaling mechanism which may be responsible for its effect. Cell growth inhibition was assessed by MTT and LDH assays. Flow cytometric analysis was performed to determine cell arrest in the cell cycle phase and apoptosis. Furthermore, to confirm the apoptotic activity of arctigenin, caspase-9 and -3 activities analysis was performed. The levels of reactive oxygen species (ROS) and p38 mitogen activated protein kinase (MAPK) were investigated to determine their role in inducing apoptosis in arctigenin-treated HT-29 colon cancer cell line. MTT and LDH results demonstrated significant cell growth inhibitory effect of arctigenin on HT-29 cells in a dose-dependent manner. Furthermore, increase in cell number arrested at G2/M phase was observed in flow cytometric analysis upon arctigenin treatment. In addition, arctigenin increased the apoptotic ratio in a dose-dependent manner. The involvement of intrinsic apoptotic pathway was indicated by the activation of caspase-9 and -3. Moreover, increased ROS production, activation of p38 MAPK and changes in mitochondrial membrane potential (ΔΨm) also revealed the role of intrinsic apoptotic signaling pathway in cell growth inhibition after arctigenin exposure. Arctigenin induces apoptosis in HT-29 colon cancer cells by regulating ROS and p38 MAPK pathways.

Calculation of vehicle delay at signal-controlled intersections with adaptive traffic control algorithm

Directory of Open Access Journals (Sweden)

Andronov Roman

2018-01-01

Full Text Available By widely introducing information technology tools in the field of traffic control, it is possible to increase the capacity of hubs and reduce vehicle delays. Adaptive traffic light control is one of such tools. Its effectiveness can be assessed through traffic flow simulation. The aim of this study is to create a simulation model of a signal-controlled intersection that can be used to assess the effectiveness of adaptive control in various traffic situations, including the presence or absence of pedestrian traffic through an intersection. The model is based on a numerical experiment conducted using the Monte Carlo method. As a result of the study, vehicle delays, queue length and duration of traffic light cycles are calculated subject to different intensities of incoming traffic flows, and the presence or absence of pedestrian traffic.

Aluminium-induced excessive ROS causes cellular damage and metabolic shifts in black gram Vigna mungo (L.) Hepper.

Science.gov (United States)

Chowra, Umakanta; Yanase, Emiko; Koyama, Hiroyuki; Panda, Sanjib Kumar

2017-01-01

Aluminium-induced oxidative damage caused by excessive ROS production was evaluated in black gram pulse crop. Black gram plants were treated with different aluminium (Al 3+ ) concentrations (10, 50 and 100 μM with pH 4.7) and further the effects of Al 3+ were characterised by means of root growth inhibition, histochemical assay, ROS content analysis, protein carbonylation quantification and 1 H-NMR analysis. The results showed that aluminium induces excessive ROS production which leads to cellular damage, root injury, stunt root growth and other metabolic shifts. In black gram, Al 3+ induces cellular damage at the earliest stage of stress which was characterised from histochemical analysis. From this study, it was observed that prolonged stress can activate certain aluminium detoxification defence mechanism. Probably excessive ROS triggers such defence mechanism in black gram. Al 3+ can induce excessive ROS initially in the root region then transported to other parts of the plant. As much as the Al 3+ concentration increases, the rate of cellular injury and ROS production also increases. But after 72 h of stress, plants showed a lowered ROS level and cellular damage which indicates the upregulation of defensive mechanisms. Metabolic shift analysis also showed that the black gram plant under stress has less metabolic content after 24 h of treatment, but gradually, it was increased after 72 h of treatment. It was assumed that ROS played the most important role as a signalling molecule for aluminium stress in black gram.

Identification of Mobile Phone and Analysis of Original Version of Videos through a Delay Time Analysis of Sound Signals from Mobile Phone Videos.

Science.gov (United States)

Hwang, Min Gu; Har, Dong Hwan

2017-11-01

This study designs a method of identifying the camera model used to take videos that are distributed through mobile phones and determines the original version of the mobile phone video for use as legal evidence. For this analysis, an experiment was conducted to find the unique characteristics of each mobile phone. The videos recorded by mobile phones were analyzed to establish the delay time of sound signals, and the differences between the delay times of sound signals for different mobile phones were traced by classifying their characteristics. Furthermore, the sound input signals for mobile phone videos used as legal evidence were analyzed to ascertain whether they have the unique characteristics of the original version. The objective of this study was to find a method for validating the use of mobile phone videos as legal evidence using mobile phones through differences in the delay times of sound input signals. © 2017 American Academy of Forensic Sciences.

Carbonylation Modification Regulates Na/K-ATPase Signaling and Salt Sensitivity: A Review and a Hypothesis.

Science.gov (United States)

Shah, Preeya T; Martin, Rebecca; Yan, Yanling; Shapiro, Joseph I; Liu, Jiang

2016-01-01

Na/K-ATPase signaling has been implicated in different physiological and pathophysiological conditions. Accumulating evidence indicates that oxidative stress not only regulates the Na/K-ATPase enzymatic activity, but also regulates its signaling and other functions. While cardiotonic steroids (CTS)-induced increase in reactive oxygen species (ROS) generation is an intermediate step in CTS-mediated Na/K-ATPase signaling, increase in ROS alone also stimulates Na/K-ATPase signaling. Based on literature and our observations, we hypothesize that ROS have biphasic effects on Na/K-ATPase signaling, transcellular sodium transport, and urinary sodium excretion. Oxidative modulation, in particular site specific carbonylation of the Na/K-ATPase α1 subunit, is a critical step in proximal tubular Na/K-ATPase signaling and decreased transcellular sodium transport leading to increases in urinary sodium excretion. However, once this system is overstimulated, the signaling, and associated changes in sodium excretion are blunted. This review aims to evaluate ROS-mediated carbonylation of the Na/K-ATPase, and its potential role in the regulation of pump signaling and sodium reabsorption in the renal proximal tubule (RPT).

The role of TGF-β1–miR-21–ROS pathway in bystander responses induced by irradiated non-small-cell lung cancer cells

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Jiang, Y; Chen, X; Tian, W; Yin, X; Wang, J; Yang, H

2014-01-01

Background: Many studies have indicated an important implication of radiation-induced bystander effects (RIBEs) in cancer radiotherapy, but the detailed signalling remains unclear. Methods: The roles of tumour growth factor-beta1 (TGF-β1) and miR-21 in medium-mediated RIBEs in H1299 non-small-cell lung cancer cells were investigated using DNA damage, changes in proliferation and levels of reactive oxygen species (ROS) as end points. SB431542, a specific inhibitor of TGF-β type 1 receptor kinases, was used to inhibit TGF-β1 pathways in irradiated and bystander cells. Exogenous miR-21 regulation was achieved through inhibitor or mimic transfection. Results: Compared with relative sham-radiation-conditioned medium, radiation-conditioned medium (RCM) from irradiated cells 1 h post radiation (1-h RCM) caused an increase in ROS levels and DNA damage in bystander cells, while 18-h RCM induced cell cycle delay and proliferation inhibition. All these effects were eliminated by TGF-βR1 inhibition. One-hour RCM upregulated miR-21 expression in bystander cells, and miR-21 inhibitor abolished bystander oxidative stress and DNA damage. Eighteen-hour RCM downregulated miR-21 of bystander cells, and miR-21 mimic eliminated bystander proliferation inhibition. Furthermore, the dysregulation of miR-21 was attenuated by TGF-βR1 inhibition. Conclusions: The TGF-β1–miR-21–ROS pathway of bystander cells has an important mediating role in RIBEs in H1299 cells. PMID:24992582

Singlet oxygen and ROS in a new light: low-dose subcellular photodynamic treatment enhances proliferation at the single cell level.

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Blázquez-Castro, Alfonso; Breitenbach, Thomas; Ogilby, Peter R

2014-09-01

Two-photon excitation of a sensitizer with a focused laser beam was used to create a spatially-localized subcellular population of reactive oxygen species, ROS, in single HeLa cells. The sensitizer used was protoporphyrin IX, PpIX, endogenously derived from 5-aminolevulinic acid delivered to the cells. Although we infer that singlet oxygen, O2(a(1)Δg), is one ROS produced upon irradiation of PpIX under these conditions, it is possible that the superoxide ion, O2(-˙), may also play a role in this system. With a "high" dose of PpIX-sensitized ROS, the expected death of the cell was observed. However, under "low dose" conditions, clear signs of cell proliferation were observed. The present results facilitate studies of ROS-mediated signalling in imaging-based single cell experiments.

Arsenic and chromium in drinking water promote tumorigenesis in a mouse colitis-associated colorectal cancer model and the potential mechanism is ROS-mediated Wnt/β-catenin signaling pathway

Energy Technology Data Exchange (ETDEWEB)

Wang, Xin; Mandal, Ardhendu K. [Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536 (United States); Saito, Hiroshi [Department of Surgery and Physiology, Lucille P. Markey Cancer Center, University of Kentucky, Lexington, KY 40536 (United States); Pulliam, Joseph F.; Lee, Eun Y. [Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY 40536 (United States); Ke, Zun-Ji; Lu, Jian; Ding, Songze [Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536 (United States); Li, Li [Department of Family Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Shelton, Brent J.; Tucker, Thomas [Markey Cancer Control Program, University of Kentucky, Lexington, KY 40504 (United States); Evers, B. Mark [Department of Surgery and Physiology, Lucille P. Markey Cancer Center, University of Kentucky, Lexington, KY 40536 (United States); Zhang, Zhuo [Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536 (United States); Shi, Xianglin, E-mail: xshi5@uky.edu [Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536 (United States)

2012-07-01

Exposure to carcinogenic metals, such as trivalent arsenic [As(III)] and hexavalent chromium [Cr(VI)], through drinking water is a major global public health problem and is associated with various cancers. However, the mechanism of their carcinogenicity remains unclear. In this study, we used azoxymethane/dextran sodium sulfate (AOM/DSS)-induced mouse colitis-associated colorectal cancer model to investigate their tumorigenesis. Our results demonstrate that exposure to As(III) or Cr(VI), alone or in combination, together with AOM/DSS pretreatment has a promotion effect, increasing the colorectal tumor incidence, multiplicity, size, and grade, as well as cell inflammatory response. Two-dimensional differential gel electrophoresis coupled with mass spectrometry revealed that As(III) or Cr(VI) treatment alone significantly changed the density of proteins. The expression of β-catenin and phospho-GSK was increased by treatment of carcinogenic metals alone. Concomitantly, the expression of NADPH oxidase1 (NOX1) and the level of 8-OHdG were also increased by treatment of carcinogenic metals alone. Antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, were decreased. Similarly, in an in vitro system, exposure of CRL-1807 to carcinogenic metals increased reactive oxygen species (ROS) generation, the expression of β-catenin, phospho-GSK, and NOX1. Inhibition of ROS generation by addition of SOD or catalase inhibited β-catenin expression and activity. Our study provides a new animal model to study the carcinogenicity of As(III) and Cr(VI) and suggests that As(III) and Cr(VI) promote colorectal cancer tumorigenesis, at least partly, through ROS-mediated Wnt/β-catenin signaling pathway. -- Highlights: ► Carcinogenic metals in drinking water promote colorectal tumor formation in vivo. ► Carcinogenic metals induce β-catenin activation in vivo and in vitro. ► ROS generation induced by carcinogenic metals mediated β-catenin activation.

Arsenic and chromium in drinking water promote tumorigenesis in a mouse colitis-associated colorectal cancer model and the potential mechanism is ROS-mediated Wnt/β-catenin signaling pathway

International Nuclear Information System (INIS)

Wang, Xin; Mandal, Ardhendu K.; Saito, Hiroshi; Pulliam, Joseph F.; Lee, Eun Y.; Ke, Zun-Ji; Lu, Jian; Ding, Songze; Li, Li; Shelton, Brent J.; Tucker, Thomas; Evers, B. Mark; Zhang, Zhuo; Shi, Xianglin

2012-01-01

Exposure to carcinogenic metals, such as trivalent arsenic [As(III)] and hexavalent chromium [Cr(VI)], through drinking water is a major global public health problem and is associated with various cancers. However, the mechanism of their carcinogenicity remains unclear. In this study, we used azoxymethane/dextran sodium sulfate (AOM/DSS)-induced mouse colitis-associated colorectal cancer model to investigate their tumorigenesis. Our results demonstrate that exposure to As(III) or Cr(VI), alone or in combination, together with AOM/DSS pretreatment has a promotion effect, increasing the colorectal tumor incidence, multiplicity, size, and grade, as well as cell inflammatory response. Two-dimensional differential gel electrophoresis coupled with mass spectrometry revealed that As(III) or Cr(VI) treatment alone significantly changed the density of proteins. The expression of β-catenin and phospho-GSK was increased by treatment of carcinogenic metals alone. Concomitantly, the expression of NADPH oxidase1 (NOX1) and the level of 8-OHdG were also increased by treatment of carcinogenic metals alone. Antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, were decreased. Similarly, in an in vitro system, exposure of CRL-1807 to carcinogenic metals increased reactive oxygen species (ROS) generation, the expression of β-catenin, phospho-GSK, and NOX1. Inhibition of ROS generation by addition of SOD or catalase inhibited β-catenin expression and activity. Our study provides a new animal model to study the carcinogenicity of As(III) and Cr(VI) and suggests that As(III) and Cr(VI) promote colorectal cancer tumorigenesis, at least partly, through ROS-mediated Wnt/β-catenin signaling pathway. -- Highlights: ► Carcinogenic metals in drinking water promote colorectal tumor formation in vivo. ► Carcinogenic metals induce β-catenin activation in vivo and in vitro. ► ROS generation induced by carcinogenic metals mediated β-catenin activation.

Andrographolide ameliorates OVA-induced lung injury in mice by suppressing ROS-mediated NF-κB signaling and NLRP3 inflammasome activation.

Science.gov (United States)

Peng, Shuang; Gao, Jian; Liu, Wen; Jiang, Chunhong; Yang, Xiaoling; Sun, Yang; Guo, Wenjie; Xu, Qiang

2016-12-06

In this study, we attempted to explore the effect and possible mechanism of Andrographolide on OVA-induced asthma. OVA challenge induced significant airway inflammatory cell recruitment and lung histological alterations, which were ameliorated by Andrographolide. The protein levels of cytokines in bron-choalveolar fluid (BALF) and serum were reduced by Andrographolide administration as well as the mRNA levels in lung tissue. Mechanically, Andrographolide markedly hampered the activation of nuclear factor-κB (NF-κB) and NLRP3 inflammasome both in vivo and vitro thus decreased levels of TNF-α and IL-1β. Finally, we confirmed that ROS scavenging was responsible for Andrographolide's inactivation of NF-κB and NLRP3 inflammasome signaling. Our study here revealed the effect and possible mechanism of Andrographolide on asthma, which may represent a new therapeutic approach for treating this disease.

A small molecule polyamine oxidase inhibitor blocks androgen-induced oxidative stress and delays prostate cancer progression in the transgenic adenocarcinoma of the mouse prostate model.

Science.gov (United States)

Basu, Hirak S; Thompson, Todd A; Church, Dawn R; Clower, Cynthia C; Mehraein-Ghomi, Farideh; Amlong, Corey A; Martin, Christopher T; Woster, Patrick M; Lindstrom, Mary J; Wilding, George

2009-10-01

High levels of reactive oxygen species (ROS) present in human prostate epithelia are an important etiologic factor in prostate cancer (CaP) occurrence, recurrence, and progression. Androgen induces ROS production in the prostate by a yet unknown mechanism. Here, to the best of our knowledge, we report for the first time that androgen induces an overexpression of spermidine/spermine N1-acetyltransferase, the rate-limiting enzyme in the polyamine oxidation pathway. As prostatic epithelia produce a large excess of polyamines, the androgen-induced polyamine oxidation that produces H2O2 could be a major reason for the high ROS levels in the prostate epithelia. A small molecule polyamine oxidase inhibitor N,N'-butanedienyl butanediamine (MDL 72,527 or CPC-200) effectively blocks androgen-induced ROS production in human CaP cells, as well as significantly delays CaP progression and death in animals developing spontaneous CaP. These data show that polyamine oxidation is not only a major pathway for ROS production in prostate, but inhibiting this pathway also successfully delays CaP progression.

Redox signaling in the growth and development of colonial hydroids.

Science.gov (United States)

Blackstone, Neil W

2003-02-01

Redox signaling provides a quick and efficient mechanism for clonal or colonial organisms to adapt their growth and development to aspects of the environment, e.g. the food supply. A 'signature' of mitochondrial redox signaling, particularly as mediated by reactive oxygen species (ROS), can be elucidated by experimental manipulation of the electron transport chain. The major sites of ROS formation are found at NADH dehydrogenase of complex I and at the interface between coenzyme Q and complex III. Inhibitors of complex III should thus upregulate ROS from both sites; inhibitors of complex I should upregulate ROS from the first but not the second site, while uncouplers of oxidative phosphorylation should downregulate ROS from both sites. To investigate the possibility of such redox signaling, perturbations of colony growth and development were carried out using the hydroid Podocoryna carnea. Oxygen uptake of colonies was measured to determine comparable physiological doses of antimycin A(1) (an inhibitor of complex III), rotenone (an inhibitor of complex I) and carbonyl cyanide m-chlorophenylhydrazone (CCCP; an uncoupler of oxidative phosphorylation). Using these doses, clear effects on colony growth and development were obtained. Treatment with antimycin A(1) results in 'runner-like' colony growth, with widely spaced polyps and stolon branches, while treatment with CCCP results in 'sheet-like' growth, with closely spaced polyps and stolon branches. Parallel results have been obtained previously with azide, an inhibitor of complex IV, and dinitrophenol, another uncoupler of oxidative phosphorylation. Perhaps surprisingly, rotenone produced effects on colony development similar to those of CCCP. Assays of peroxides using 2',7'-dichlorofluorescin diacetate and fluorescent microscopy suggest a moderate difference in ROS formation between the antimycin and rotenone treatments. The second site of ROS formation (the interface between coenzyme Q and complex III) may thus

Cadmium-induced teratogenicity: Association with ROS-mediated endoplasmic reticulum stress in placenta

International Nuclear Information System (INIS)

Wang, Zhen; Wang, Hua; Xu, Zhong Mei; Ji, Yan-Li; Chen, Yuan-Hua; Zhang, Zhi-Hui; Zhang, Cheng; Meng, Xiu-Hong; Zhao, Mei; Xu, De-Xiang

2012-01-01

The placenta is essential for sustaining the growth of the fetus. An increased endoplasmic reticulum (ER) stress has been associated with the impaired placental and fetal development. Cadmium (Cd) is a potent teratogen that caused fetal malformation and growth restriction. The present study investigated the effects of maternal Cd exposure on placental and fetal development. The pregnant mice were intraperitoneally injected with CdCl 2 (4.5 mg/kg) on gestational day 9. As expected, maternal Cd exposure during early limb development significantly increased the incidences of forelimb ectrodactyly in fetuses. An obvious impairment in the labyrinth, a highly developed tissue of blood vessels, was observed in placenta of mice treated with CdCl 2 . In addition, maternal Cd exposure markedly repressed cell proliferation and increased apoptosis in placenta. An additional experiment showed that maternal Cd exposure significantly upregulated the expression of GRP78, an ER chaperone. Moreover, maternal Cd exposure induced the phosphorylation of placental eIF2α, a downstream molecule of PERK signaling. In addition, maternal Cd exposure significantly increased the level of placental CHOP, another target of PERK signaling, indicating that the unfolded protein response (UPR) signaling was activated in placenta of mice treated with CdCl 2 . Interestingly, alpha-phenyl-N-t-butylnitrone, a free radical spin-trapping agent, significantly alleviated Cd-induced placental ER stress and UPR. Taken together, these results suggest that reactive oxygen species (ROS)-mediated ER stress might be involved in Cd-induced impairment on placental and fetal development. Antioxidants may be used as pharmacological agents to protect against Cd-induced fetal malformation and growth restriction. -- Highlights: ► Cd induces fetal malformation and growth restriction. ► Cd induced placental ER stress and UPR. ► PBN alleviates Cd-induced ER stress and UPR in placenta. ► ROS-mediated ER stress might

Demodicidosis en pacientes con rosácea

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Edhizon Trejo Mucha

2007-01-01

Full Text Available Objetivo: Determinar la frecuencia de demodicidosis y sus características clínicas en pacientes con rosácea. Materiales y métodos: Estudio de casos y controles en 42 pacientes con rosácea y 42 controles para describir la presencia y densidad de D. folliculorum. El estudio se realizó en el Hospital Nacional Cayetano Heredia entre marzo y setiembre del 2004, utilizándose la técnica de Tello. Resultados: Demodex folliculorum fue encontrado en los 42 pacientes con rosácea (100% y en 13 (31,0% del grupo control, (p= 0,000. La exposición a gatos, la crianza de roedores y cerdos, la seborrea y el uso de corticoides tópicos fueron mas frecuentes en los pacientes con rosácea. Conclusiones: La presencia de Demodex folliculorum fue más frecuente en los pacientes con rosácea. (Rev Med Hered 2007;18:15-21.

Endogenous mechanisms of reactive oxygen species (ROS generation

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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.

A TOTP-based enhanced route optimization procedure for mobile IPv6 to reduce handover delay and signalling overhead.

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Shah, Peer Azmat; Hasbullah, Halabi B; Lawal, Ibrahim A; Aminu Mu'azu, Abubakar; Tang Jung, Low

2014-01-01

Due to the proliferation of handheld mobile devices, multimedia applications like Voice over IP (VoIP), video conferencing, network music, and online gaming are gaining popularity in recent years. These applications are well known to be delay sensitive and resource demanding. The mobility of mobile devices, running these applications, across different networks causes delay and service disruption. Mobile IPv6 was proposed to provide mobility support to IPv6-based mobile nodes for continuous communication when they roam across different networks. However, the Route Optimization procedure in Mobile IPv6 involves the verification of mobile node's reachability at the home address and at the care-of address (home test and care-of test) that results in higher handover delays and signalling overhead. This paper presents an enhanced procedure, time-based one-time password Route Optimization (TOTP-RO), for Mobile IPv6 Route Optimization that uses the concepts of shared secret Token, time based one-time password (TOTP) along with verification of the mobile node via direct communication and maintaining the status of correspondent node's compatibility. The TOTP-RO was implemented in network simulator (NS-2) and an analytical analysis was also made. Analysis showed that TOTP-RO has lower handover delays, packet loss, and signalling overhead with an increased level of security as compared to the standard Mobile IPv6's Return-Routability-based Route Optimization (RR-RO).

A TOTP-Based Enhanced Route Optimization Procedure for Mobile IPv6 to Reduce Handover Delay and Signalling Overhead

Science.gov (United States)

Shah, Peer Azmat; Hasbullah, Halabi B.; Lawal, Ibrahim A.; Aminu Mu'azu, Abubakar; Tang Jung, Low

2014-01-01

Due to the proliferation of handheld mobile devices, multimedia applications like Voice over IP (VoIP), video conferencing, network music, and online gaming are gaining popularity in recent years. These applications are well known to be delay sensitive and resource demanding. The mobility of mobile devices, running these applications, across different networks causes delay and service disruption. Mobile IPv6 was proposed to provide mobility support to IPv6-based mobile nodes for continuous communication when they roam across different networks. However, the Route Optimization procedure in Mobile IPv6 involves the verification of mobile node's reachability at the home address and at the care-of address (home test and care-of test) that results in higher handover delays and signalling overhead. This paper presents an enhanced procedure, time-based one-time password Route Optimization (TOTP-RO), for Mobile IPv6 Route Optimization that uses the concepts of shared secret Token, time based one-time password (TOTP) along with verification of the mobile node via direct communication and maintaining the status of correspondent node's compatibility. The TOTP-RO was implemented in network simulator (NS-2) and an analytical analysis was also made. Analysis showed that TOTP-RO has lower handover delays, packet loss, and signalling overhead with an increased level of security as compared to the standard Mobile IPv6's Return-Routability-based Route Optimization (RR-RO). PMID:24688398

Hydrogen sulfide protects against chemical hypoxia-induced injury by inhibiting ROS-activated ERK1/2 and p38MAPK signaling pathways in PC12 cells.

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Aiping Lan

Full Text Available Hydrogen sulfide (H(2S has been proposed as a novel neuromodulator and neuroprotective agent. Cobalt chloride (CoCl(2 is a well-known hypoxia mimetic agent. We have demonstrated that H(2S protects against CoCl(2-induced injuries in PC12 cells. However, whether the members of mitogen-activated protein kinases (MAPK, in particular, extracellular signal-regulated kinase1/2(ERK1/2 and p38MAPK are involved in the neuroprotection of H(2S against chemical hypoxia-induced injuries of PC12 cells is not understood. We observed that CoCl(2 induced expression of transcriptional factor hypoxia-inducible factor-1 alpha (HIF-1α, decreased cystathionine-β synthase (CBS, a synthase of H(2S expression, and increased generation of reactive oxygen species (ROS, leading to injuries of the cells, evidenced by decrease in cell viability, dissipation of mitochondrial membrane potential (MMP , caspase-3 activation and apoptosis, which were attenuated by pretreatment with NaHS (a donor of H(2S or N-acetyl-L cystein (NAC, a ROS scavenger. CoCl(2 rapidly activated ERK1/2, p38MAPK and C-Jun N-terminal kinase (JNK. Inhibition of ERK1/2 or p38MAPK or JNK with kinase inhibitors (U0126 or SB203580 or SP600125, respectively or genetic silencing of ERK1/2 or p38MAPK by RNAi (Si-ERK1/2 or Si-p38MAPK significantly prevented CoCl(2-induced injuries. Pretreatment with NaHS or NAC inhibited not only CoCl(2-induced ROS production, but also phosphorylation of ERK1/2 and p38MAPK. Thus, we demonstrated that a concurrent activation of ERK1/2, p38MAPK and JNK participates in CoCl(2-induced injuries and that H(2S protects PC12 cells against chemical hypoxia-induced injuries by inhibition of ROS-activated ERK1/2 and p38MAPK pathways. Our results suggest that inhibitors of ERK1/2, p38MAPK and JNK or antioxidants may be useful for preventing and treating hypoxia-induced neuronal injury.

A reaction-diffusion model of ROS-induced ROS release in a mitochondrial network.

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Lufang Zhou

2010-01-01

Full Text Available Loss of mitochondrial function is a fundamental determinant of cell injury and death. In heart cells under metabolic stress, we have previously described how the abrupt collapse or oscillation of the mitochondrial energy state is synchronized across the mitochondrial network by local interactions dependent upon reactive oxygen species (ROS. Here, we develop a mathematical model of ROS-induced ROS release (RIRR based on reaction-diffusion (RD-RIRR in one- and two-dimensional mitochondrial networks. The nodes of the RD-RIRR network are comprised of models of individual mitochondria that include a mechanism of ROS-dependent oscillation based on the interplay between ROS production, transport, and scavenging; and incorporating the tricarboxylic acid (TCA cycle, oxidative phosphorylation, and Ca(2+ handling. Local mitochondrial interaction is mediated by superoxide (O2.- diffusion and the O2.(--dependent activation of an inner membrane anion channel (IMAC. In a 2D network composed of 500 mitochondria, model simulations reveal DeltaPsi(m depolarization waves similar to those observed when isolated guinea pig cardiomyocytes are subjected to a localized laser-flash or antioxidant depletion. The sensitivity of the propagation rate of the depolarization wave to O(2.- diffusion, production, and scavenging in the reaction-diffusion model is similar to that observed experimentally. In addition, we present novel experimental evidence, obtained in permeabilized cardiomyocytes, confirming that DeltaPsi(m depolarization is mediated specifically by O2.-. The present work demonstrates that the observed emergent macroscopic properties of the mitochondrial network can be reproduced in a reaction-diffusion model of RIRR. Moreover, the findings have uncovered a novel aspect of the synchronization mechanism, which is that clusters of mitochondria that are oscillating can entrain mitochondria that would otherwise display stable dynamics. The work identifies the

Viewing oxidative stress through the lens of oxidative signalling rather than damage.

Science.gov (United States)

Foyer, Christine H; Ruban, Alexander V; Noctor, Graham

2017-03-07

Concepts of the roles of reactive oxygen species (ROS) in plants and animals have shifted in recent years from focusing on oxidative damage effects to the current view of ROS as universal signalling metabolites. Rather than having two opposing activities, i.e. damage and signalling, the emerging concept is that all types of oxidative modification/damage are involved in signalling, not least in the induction of repair processes. Examining the multifaceted roles of ROS as crucial cellular signals, we highlight as an example the loss of photosystem II function called photoinhibition, where photoprotection has classically been conflated with oxidative damage. © 2017 The Author(s). This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution Licence 4.0 (CC BY).

ROS - Robotiikan tutkimustyökalusta kohti kaupallista menestystarinaa

OpenAIRE

Ahonen, Mika

2017-01-01

Avoimen lähdekoodin ROS-käyttöjärjestelmä on yleisesti tutkimushankkeissa käytetty robotiikan kehitysalusta. Tutkielman tavoitteena on ollut arvioida onko ROS järjestelmä, joka tulee yleistymään myös robotiikan kaupallisissa ratkaisuissa. ROS-pohjaisia kaupallisia tuotteita on jo olemassa ja sen käyttöä on pilotoitu runsaasti erilaisilla sovellusalueilla. Erityisesti palvelu- ja pilvirobotiikan alueilla ROSilla on kasvavaa potentiaalia. ROS on vielä kehittyvä järjestelmä ja ei nykyisellään...

ROS accumulation and IGF-IR inhibition contribute to fenofibrate/PPARα -mediated inhibition of Glioma cell motility in vitro

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Del Valle Luis

2010-06-01

Full Text Available Abstract Background Glioblastomas are characterized by rapid cell growth, aggressive CNS infiltration, and are resistant to all known anticancer regimens. Recent studies indicate that fibrates and statins possess anticancer potential. Fenofibrate is a potent agonist of peroxisome proliferator activated receptor alpha (PPARα that can switch energy metabolism from glycolysis to fatty acid β-oxidation, and has low systemic toxicity. Fenofibrate also attenuates IGF-I-mediated cellular responses, which could be relevant in the process of glioblastoma cell dispersal. Methods The effects of fenofibrate on Glioma cell motility, IGF-I receptor (IGF-IR signaling, PPARα activity, reactive oxygen species (ROS metabolism, mitochondrial potential, and ATP production were analyzed in human glioma cell lines. Results Fenofibrate treatment attenuated IGF-I signaling responses and repressed cell motility of LN-229 and T98G Glioma cell lines. In the absence of fenofibrate, specific inhibition of the IGF-IR had only modest effects on Glioma cell motility. Further experiments revealed that PPARα-dependent accumulation of ROS is a strong contributing factor in Glioma cell lines responses to fenofibrate. The ROS scavenger, N-acetyl-cysteine (NAC, restored cell motility, improved mitochondrial potential, and increased ATP levels in fenofibrate treated Glioma cell lines. Conclusions Our results indicate that although fenofibrate-mediated inhibition of the IGF-IR may not be sufficient in counteracting Glioma cell dispersal, PPARα-dependent metabolic switch and the resulting ROS accumulation strongly contribute to the inhibition of these devastating brain tumor cells.

Bioactive Peptides from Angelica sinensis Protein Hydrolyzate Delay Senescence in Caenorhabditis elegans through Antioxidant Activities

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Qiangqiang Wang

2016-01-01

Full Text Available Since excessive reactive oxygen species (ROS is known to be associated with aging and age-related diseases, strategies modulating ROS level and antioxidant defense systems may contribute to the delay of senescence. Here we show that the protein hydrolyzate from Angelica sinensis was capable of increasing oxidative survival of the model animal Caenorhabditis elegans intoxicated by paraquat. The hydrolyzate was then fractionated by ultrafiltration, and the antioxidant fraction (<3 kDa was purified by gel filtration to obtain the antioxidant A. sinensis peptides (AsiPeps, which were mostly composed of peptides with <20 amino acid residues. Further studies demonstrate that AsiPeps were able to reduce the endogenous ROS level, increase the activities of the antioxidant enzymes superoxide dismutase and catalase, and decrease the content of the lipid peroxidation product malondialdehyde in nematodes treated with paraquat or undergoing senescence. AsiPeps were also shown to reduce age pigments accumulation and extend lifespan but did not affect the food-intake behavior of the nematodes. Taken together, our results demonstrate that A. sinensis peptides (AsiPeps are able to delay aging process in C. elegans through antioxidant activities independent of dietary restriction.

Tolerance to drought and salt stress in plants: Unraveling the signaling networks

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Dortje eGolldack

2014-04-01

Full Text Available Tolerance of plants to abiotic stressors such as drought and salinity is triggered by complex multicomponent signaling pathways to restore cellular homeostasis and promote survival. Major plant transcription factor families such as bZIP, NAC, AP2/ERF and MYB orchestrate regulatory networks underlying abiotic stress tolerance. Sucrose nonfermenting 1-related protein kinase 2 (SnRK2 and MAPK pathways contribute to initiation of stress adaptive downstream responses and promote plant growth and development. As a convergent point of multiple abiotic cues, cellular effects of environmental stresses are not only imbalances of ionic and osmotic homeostasis but also impaired photosynthesis, cellular energy depletion, and redox imbalances. Recent evidence of regulatory systems that link sensing and signaling of environmental conditions and the intracellular redox status have shed light on interfaces of stress and energy signaling. ROS (reactive oxygen species cause severe cellular damage by peroxidation and de-esterification of membrane lipids, however, current models also define a pivotal signaling function of ROS in triggering tolerance against stress. Recent research advances suggest and support a regulatory role of ROS in the cross talks of stress triggered hormonal signaling such as the abscisic acid (ABA pathway and endogenously induced redox and metabolite signals. Here, we discuss and review the versatile molecular convergence in the abiotic stress responsive signaling networks in the context of ROS and lipid derived signals and the specific role of stomatal signaling.

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.

High Glucose and Lipopolysaccharide Prime NLRP3 Inflammasome via ROS/TXNIP Pathway in Mesangial Cells

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Hong Feng

2016-01-01

Full Text Available While inflammation is considered a central component in the development in diabetic nephropathy, the mechanism remains unclear. The NLRP3 inflammasome acts as both a sensor and a regulator of the inflammatory response. The NLRP3 inflammasome responds to exogenous and endogenous danger signals, resulting in cleavage of procaspase-1 and activation of cytokines IL-1β, IL-18, and IL-33, ultimately triggering an inflammatory cascade reaction. This study observed the expression of NLRP3 inflammasome signaling stimulated by high glucose, lipopolysaccharide, and reactive oxygen species (ROS inhibitor N-acetyl-L-cysteine in glomerular mesangial cells, aiming to elucidate the mechanism by which the NLRP3 inflammasome signaling pathway may contribute to diabetic nephropathy. We found that the expression of thioredoxin-interacting protein (TXNIP, NLRP3, and IL-1β was observed by immunohistochemistry in vivo. Simultaneously, the mRNA and protein levels of TXNIP, NLRP3, procaspase-1, and IL-1β were significantly induced by high glucose concentration and lipopolysaccharide in a dose-dependent and time-dependent manner in vitro. This induction by both high glucose and lipopolysaccharide was significantly inhibited by N-acetyl-L-cysteine. Our results firstly reveal that high glucose and lipopolysaccharide activate ROS/TXNIP/ NLRP3/IL-1β inflammasome signaling in glomerular mesangial cells, suggesting a mechanism by which inflammation may contribute to the development of diabetic nephropathy.

The Roles of ROS and Caspases in TRAIL-Induced Apoptosis and Necroptosis in Human Pancreatic Cancer Cells.

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Min Zhang

Full Text Available Death signaling provided by tumor necrosis factor (TNF-related apoptosis-inducing ligand (TRAIL can induce death in cancer cells with little cytotoxicity to normal cells; this cell death has been thought to involve caspase-dependent apoptosis. Reactive oxygen species (ROS are also mediators that induce cell death, but their roles in TRAIL-induced apoptosis have not been elucidated fully. In the current study, we investigated ROS and caspases in human pancreatic cancer cells undergoing two different types of TRAIL-induced cell death, apoptosis and necroptosis. TRAIL treatment increased ROS in two TRAIL-sensitive pancreatic cancer cell lines, MiaPaCa-2 and BxPC-3, but ROS were involved in TRAIL-induced apoptosis only in MiaPaCa-2 cells. Unexpectedly, inhibition of ROS by either N-acetyl-L-cysteine (NAC, a peroxide inhibitor, or Tempol, a superoxide inhibitor, increased the annexin V-/propidium iodide (PI+ early necrotic population in TRAIL-treated cells. Additionally, both necrostatin-1, an inhibitor of receptor-interacting protein kinase 1 (RIP1, and siRNA-mediated knockdown of RIP3 decreased the annexin V-/PI+ early necrotic population after TRAIL treatment. Furthermore, an increase in early apoptosis was induced in TRAIL-treated cancer cells under inhibition of either caspase-2 or -9. Caspase-2 worked upstream of caspase-9, and no crosstalk was observed between ROS and caspase-2/-9 in TRAIL-treated cells. Together, these results indicate that ROS contribute to TRAIL-induced apoptosis in MiaPaCa-2 cells, and that ROS play an inhibitory role in TRAIL-induced necroptosis of MiaPaCa-2 and BxPC-3 cells, with caspase-2 and -9 playing regulatory roles in this process.

Optimizing the Universal Robots ROS driver

DEFF Research Database (Denmark)

Andersen, Thomas Timm

improvement both in terms of faster reaction as well as making it possible to control the robot using either ros_control or ordinary joint speed commands, which is required for many types of sensory based control like visual servoing. The developed driver is compared to the drivers already existing in the ROS...

Brucella Melitensis 16M Regulates the Effect of AIR Domain on Inflammatory Factors, Autophagy, and Apoptosis in Mouse Macrophage through the ROS Signaling Pathway.

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Tiansen Li

Full Text Available Brucellosis is a highly contagious zoonosis caused by Brucella. Brucella can invade and persist inside host cells, which results in chronic infection. We constructed AIR interference and overexpression lentiviruses to acquire AIR interference, overexpression, and rescue stable expression cell lines. We also established a Brucella melitensis 16M-infected macrophage model, which was treated with either the vehicle control or NAC (ROS scavenger N-acetylcysteine (NAC for 0, 3, 6, 12, and 24 h. Confocal laser microscopy, transmission electron microscopy, fluorescence quantitative PCR, flow cytometry, ELISA, and Western blot were used to detect inflammation, cell autophagy and apoptosis-related protein expression levels, ROS levels, and the distribution of mitochondria. It was found that after interference and overexpression of AIR, ROS release was significantly changed, and mitochondria became abnormally aggregated. B. melitensis 16M activated the NLRP3/AIM2 inflammatory complex, and induced RAW264.7 cells to secrete IL-1β and IL-18 through the ROS pathway. B. melitensis 16M also altered autophagy-related gene expression, increased autophagy activity, and induced cell apoptosis through the ROS pathway. The results showed that after B. melitensis 16M infection, ROS induced apoptosis, inflammation, and autophagy while AIR inhibited autophagosome maturation and autophagy initiation. Autophagy negatively regulated the activation of inflammasomes and prevented inflammation from occurring. In addition, mitophagy could promote cell apoptosis.

Gamma radiation protects fruit quality in tomato by inhibiting the production of reactive oxygen species (ROS) and ethylene

International Nuclear Information System (INIS)

Mahesh Kumar; Sumedha Ahuja; Bhupinder Singh; Anil Dahuja; Raj Kumar

2014-01-01

Experiments were conducted to examine the individual and combined effect of two different electromagnetic energies, i.e., gamma ray viz 0.1, 0.5 and 1 kGy and static magnetic field (50 mT for 1 h) and their combination (0.5 kGy + 50 mT) on the shelf life of tomato and evaluates the biochemical attributes that influence the fruit ripening and fruit quality. Magnetic field application either alone or in combination with gamma irradiation was not effective in delaying the ripening process. Gamma ray exposed fruits at 0.5 and 1 kGy showed an extended shelf life due to delayed fruit ripening and reduced lycopene synthesis and ethylene production. Efficient ROS scavenging ability and consequent reduction in oxidative damage in the irradiated treatment may cause favorable biochemical changes to facilitate delayed ripening of the tomato fruits. (author)

A TOTP-Based Enhanced Route Optimization Procedure for Mobile IPv6 to Reduce Handover Delay and Signalling Overhead

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Peer Azmat Shah

2014-01-01

Full Text Available Due to the proliferation of handheld mobile devices, multimedia applications like Voice over IP (VoIP, video conferencing, network music, and online gaming are gaining popularity in recent years. These applications are well known to be delay sensitive and resource demanding. The mobility of mobile devices, running these applications, across different networks causes delay and service disruption. Mobile IPv6 was proposed to provide mobility support to IPv6-based mobile nodes for continuous communication when they roam across different networks. However, the Route Optimization procedure in Mobile IPv6 involves the verification of mobile node’s reachability at the home address and at the care-of address (home test and care-of test that results in higher handover delays and signalling overhead. This paper presents an enhanced procedure, time-based one-time password Route Optimization (TOTP-RO, for Mobile IPv6 Route Optimization that uses the concepts of shared secret Token, time based one-time password (TOTP along with verification of the mobile node via direct communication and maintaining the status of correspondent node’s compatibility. The TOTP-RO was implemented in network simulator (NS-2 and an analytical analysis was also made. Analysis showed that TOTP-RO has lower handover delays, packet loss, and signalling overhead with an increased level of security as compared to the standard Mobile IPv6’s Return-Routability-based Route Optimization (RR-RO.

Multiplicity counting from fission detector signals with time delay effects

Science.gov (United States)

Nagy, L.; Pázsit, I.; Pál, L.

2018-03-01

In recent work, we have developed the theory of using the first three auto- and joint central moments of the currents of up to three fission chambers to extract the singles, doubles and triples count rates of traditional multiplicity counting (Pázsit and Pál, 2016; Pázsit et al., 2016). The objective is to elaborate a method for determining the fissile mass, neutron multiplication, and (α, n) neutron emission rate of an unknown assembly of fissile material from the statistics of the fission chamber signals, analogous to the traditional multiplicity counting methods with detectors in the pulse mode. Such a method would be an alternative to He-3 detector systems, which would be free from the dead time problems that would be encountered in high counting rate applications, for example the assay of spent nuclear fuel. A significant restriction of our previous work was that all neutrons born in a source event (spontaneous fission) were assumed to be detected simultaneously, which is not fulfilled in reality. In the present work, this restriction is eliminated, by assuming an independent, identically distributed random time delay for all neutrons arising from one source event. Expressions are derived for the same auto- and joint central moments of the detector current(s) as in the previous case, expressed with the singles, doubles, and triples (S, D and T) count rates. It is shown that if the time-dispersion of neutron detections is of the same order of magnitude as the detector pulse width, as they typically are in measurements of fast neutrons, the multiplicity rates can still be extracted from the moments of the detector current, although with more involved calibration factors. The presented formulae, and hence also the performance of the proposed method, are tested by both analytical models of the time delay as well as with numerical simulations. Methods are suggested also for the modification of the method for large time delay effects (for thermalised neutrons).

49 CFR 236.563 - Delay time.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Delay time. 236.563 Section 236.563 Transportation... Cab Signal Systems Rules and Instructions; Locomotives § 236.563 Delay time. Delay time of automatic... requirements of § 236.24 shall take into consideration the delay time. ...

SkiROS

DEFF Research Database (Denmark)

Rovida, Francesco; Schou, Casper; Andersen, Rasmus Skovgaard

During the last decades, the methods for intuitive task level programming of robots have become a fundamental point of interest for industrial application. The paper in hand presents SkiROS (Skill-based Robot Operating System) a novel software architecture based on the skills paradigm. The skill ...... of a flexible, highly modular system for the development of cognitive robot tasks....

Critical role of mitochondrial ROS is dependent on their site of production on the electron transport chain in ischemic heart.

Science.gov (United States)

Madungwe, Ngonidzashe B; Zilberstein, Netanel F; Feng, Yansheng; Bopassa, Jean C

2016-01-01

Reactive oxygen species (ROS) generation has been implicated in many pathologies including ischemia/reperfusion (I/R) injury. This led to multiple studies on antioxidant therapies to treat cardiovascular diseases but paradoxically, results have so far been mixed as ROS production can be beneficial as a signaling mechanism and in cardiac protection via preconditioning interventions. We investigated whether the differential impact of increased ROS in injury as well as in protection could be explained by their site of production on the mitochondrial electron transport chain. Using amplex red to measure ROS production, we found that mitochondria isolated from hearts after I/R produced more ROS than non-ischemic when complex I substrate (glutamate/malate) was used. Interestingly, the substrates of complex II (succinate) and ubiquinone (sn-glycerol 3-phosphate, G3P) produced less ROS in mitochondria from I/R hearts compared to normal healthy hearts. The inhibitors of complex I (rotenone) and complex III (antimycin A) increased ROS production when glutamate/malate and G3P were used; in contrast, they reduced ROS production when the complex II substrate was used. Mitochondrial calcium retention capacity required to induce mitochondrial permeability transition pore (mPTP) opening was measured using calcium green fluorescence and was found to be higher when mitochondria were treated with G3P and succinate compared to glutamate/malate. Furthermore, Langendorff hearts treated with glutamate/malate exhibited reduced cardiac functional recovery and increased myocardial infarct size compared to hearts treated with G3P. Thus, ROS production by the stimulated respiratory chain complexes I and III has opposite roles: cardio-deleterious when produced in complex I and cardio-protective when produced in complex III. The mechanism of these ROS involves the inhibition of the mPTP opening, a key event in cell death following ischemia/reperfusion injury.

Palmitate induces VSMC apoptosis via toll like receptor (TLR)4/ROS/p53 pathway.

Science.gov (United States)

Zhang, Yuanjun; Xia, Guanghao; Zhang, Yaqiong; Liu, Juxiang; Liu, Xiaowei; Li, Weihua; Lv, Yaya; Wei, Suhong; Liu, Jing; Quan, Jinxing

2017-08-01

Toll-like receptor 4 (TLR4) has been implicated in vascular inflammation, as well as in the pathogenesis of atherosclerosis and diabetes. Vascular smooth muscle cell (VSMC) apoptosis has been shown to induce plaque vulnerability in atherosclerosis. Previous studies reported that palmitate induced apoptosis in VSMCs; however, the role of TLR4 in palmitate-induced apoptosis in VSMCs has not yet been defined. In this study, we investigated whether or not palmitate-induced apoptosis depended on the activation of the TLR4 pathway. VSMCs were treated with or without palmitate, CRISPR/Cas9z-mediated genome editing methods were used to deplete TLR4 expression, while NADPH oxidase inhibitors were used to inhibit reactive oxygen species (ROS) generation. Cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, ROS was measured using the 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) method, the mRNA and protein expression levels of caspase 3, caspase 9, BCL-2 and p53 were studied by real-time polymerase chain reaction (RT-PCR) and ELISA. Palmitate significantly promotes VSMC apoptosis, ROS generation, and expression of caspase 3, caspase 9 and p53; while NADPH oxidase inhibitor pretreatment markedly attenuated these effects. Moreover, knockdown of TLR4 significantly blocked palmitate-induced ROS generation and VSMC apoptosis accompanied by inhibition of caspase 3, caspase 9, p53 expression and restoration of BCL-2 expression. Our results suggest that palmitate-induced apoptosis depends on the activation of the TLR4/ROS/p53 signaling pathway, and that TLR4 may be a potential therapeutic target for the prevention and treatment of atherosclerosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Fractional Delayer Utilizing Hermite Interpolation with Caratheodory Representation

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Qiang DU

2018-04-01

Full Text Available Fractional delay is indispensable for many sorts of circuits and signal processing applications. Fractional delay filter (FDF utilizing Hermite interpolation with an analog differentiator is a straightforward way to delay discrete signals. This method has a low time-domain error, but a complicated sampling module than the Shannon sampling scheme. A simplified scheme, which is based on Shannon sampling and utilizing Hermite interpolation with a digital differentiator, will lead a much higher time-domain error when the signal frequency approaches the Nyquist rate. In this letter, we propose a novel fractional delayer utilizing Hermite interpolation with Caratheodory representation. The samples of differential signal are obtained by Caratheodory representation from the samples of the original signal only. So, only one sampler is needed and the sampling module is simple. Simulation results for four types of signals demonstrate that the proposed method has significantly higher interpolation accuracy than Hermite interpolation with digital differentiator.

The Role of Na/K-ATPase Signaling in Oxidative Stress Related to Obesity and Cardiovascular Disease

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Krithika Srikanthan

2016-09-01

Full Text Available Na/K-ATPase has been extensively studied for its ion pumping function, but, in the past several decades, has been identified as a scaffolding and signaling protein. Initially it was found that cardiotonic steroids (CTS mediate signal transduction through the Na/K-ATPase and result in the generation of reactive oxygen species (ROS, which are also capable of initiating the signal cascade. However, in recent years, this Na/K-ATPase/ROS amplification loop has demonstrated significance in oxidative stress related disease states, including obesity, atherosclerosis, heart failure, uremic cardiomyopathy, and hypertension. The discovery of this novel oxidative stress signaling pathway, holds significant therapeutic potential for the aforementioned conditions and others that are rooted in ROS.

Resveratrol-Induced Downregulation of NAF-1 Enhances the Sensitivity of Pancreatic Cancer Cells to Gemcitabine via the ROS/Nrf2 Signaling Pathways

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Liang Cheng

2018-01-01

Full Text Available NAF-1 (nutrient-deprivation autophagy factor-1, which is an outer mitochondrial membrane protein, is known to play important roles in calcium metabolism, antiapoptosis, and antiautophagy. Resveratrol, a natural polyphenolic compound, is considered as a potent anticancer agent. Nevertheless, the molecular mechanisms underlying the effects of resveratrol and NAF-1 and their mediation of drug resistance in pancreatic cancer remain unclear. Here, we demonstrate that resveratrol suppresses the expression of NAF-1 in pancreatic cancer cells by inducing cellular reactive oxygen species (ROS accumulation and activating Nrf2 signaling. In addition, the knockdown of NAF-1 activates apoptosis and impedes the proliferation of pancreatic cancer cells. More importantly, the targeting of NAF-1 by resveratrol can improve the sensitivity of pancreatic cancer cells to gemcitabine. These results highlight the significance of strategies that target NAF-1, which may enhance the efficacy of gemcitabine in pancreatic cancer therapy.

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...

Classifying epileptic EEG signals with delay permutation entropy and Multi-Scale K-means.

Science.gov (United States)

Zhu, Guohun; Li, Yan; Wen, Peng Paul; Wang, Shuaifang

2015-01-01

Most epileptic EEG classification algorithms are supervised and require large training datasets, that hinder their use in real time applications. This chapter proposes an unsupervised Multi-Scale K-means (MSK-means) MSK-means algorithm to distinguish epileptic EEG signals and identify epileptic zones. The random initialization of the K-means algorithm can lead to wrong clusters. Based on the characteristics of EEGs, the MSK-means MSK-means algorithm initializes the coarse-scale centroid of a cluster with a suitable scale factor. In this chapter, the MSK-means algorithm is proved theoretically superior to the K-means algorithm on efficiency. In addition, three classifiers: the K-means, MSK-means MSK-means and support vector machine (SVM), are used to identify seizure and localize epileptogenic zone using delay permutation entropy features. The experimental results demonstrate that identifying seizure with the MSK-means algorithm and delay permutation entropy achieves 4. 7 % higher accuracy than that of K-means, and 0. 7 % higher accuracy than that of the SVM.

Literature-based discovery of diabetes- and ROS-related targets

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Pande Manjusha

2010-10-01

Full Text Available Abstract Background Reactive oxygen species (ROS are known mediators of cellular damage in multiple diseases including diabetic complications. Despite its importance, no comprehensive database is currently available for the genes associated with ROS. Methods We present ROS- and diabetes-related targets (genes/proteins collected from the biomedical literature through a text mining technology. A web-based literature mining tool, SciMiner, was applied to 1,154 biomedical papers indexed with diabetes and ROS by PubMed to identify relevant targets. Over-represented targets in the ROS-diabetes literature were obtained through comparisons against randomly selected literature. The expression levels of nine genes, selected from the top ranked ROS-diabetes set, were measured in the dorsal root ganglia (DRG of diabetic and non-diabetic DBA/2J mice in order to evaluate the biological relevance of literature-derived targets in the pathogenesis of diabetic neuropathy. Results SciMiner identified 1,026 ROS- and diabetes-related targets from the 1,154 biomedical papers (http://jdrf.neurology.med.umich.edu/ROSDiabetes/. Fifty-three targets were significantly over-represented in the ROS-diabetes literature compared to randomly selected literature. These over-represented targets included well-known members of the oxidative stress response including catalase, the NADPH oxidase family, and the superoxide dismutase family of proteins. Eight of the nine selected genes exhibited significant differential expression between diabetic and non-diabetic mice. For six genes, the direction of expression change in diabetes paralleled enhanced oxidative stress in the DRG. Conclusions Literature mining compiled ROS-diabetes related targets from the biomedical literature and led us to evaluate the biological relevance of selected targets in the pathogenesis of diabetic neuropathy.

Polymorphic ROS scavenging revealed by CCCP in a lizard

Science.gov (United States)

Olsson, Mats; Wilson, Mark; Isaksson, Caroline; Uller, Tobias

2009-07-01

Ingestion of antioxidants has been argued to scavenge circulating reactive molecules (e.g., free radicals), play a part in mate choice (by mediating access to this important resource), and perhaps increase life span. However, recent work has come to question these relationships. We have shown elsewhere in the polychromatic lizard, Ctenophorus pictus, that diet supplementation of carotenoids as antioxidants does not depress circulating natural reactive oxygen species (ROS) levels and leads to no corresponding improvement of color traits. However, a much stronger test would be to experimentally manipulate the ROS levels themselves and assess carotenoid-induced ROS depression. Here, we achieve this by using carbonyl cyanide 3-chlorophenylhydrazone, which elevates superoxide (SO) formation approximately threefold at 10 μM in this model system. We then look for depressing effects on ROS of the carotenoids in order to assess whether ‘super-production’ of SO makes carotenoid effects on elevated ROS levels detectable. The rationale for this treatment was that if not even such elevated levels of SO are reduced by carotenoid supplementation, the putative link carotenoids, ROS depression, and mate quality (in terms of antioxidant capacity) is highly questionable. We conclude that there is no significant effect of carotenoids on mean SO levels even at the induced ROS levels. However, our results showed a significant interaction effect between carotenoid treatment and male color, with red males having higher ROS levels than yellow males. We suggest that this may be because different pigments are differently involved in the generation of the integumental colors in the two morphs with concomitant effects on ROS depletion depending on carotenoid uptake or allocation to coloration and antioxidation.

Extract from Edible Red Seaweed (Gelidium amansii) Inhibits Lipid Accumulation and ROS Production during Differentiation in 3T3-L1 Cells.

Science.gov (United States)

Seo, Min-Jung; Lee, Ok-Hwan; Choi, Hyeon-Son; Lee, Boo-Yong

2012-06-01

Gelidium (G.) amansii is a red alga widely distributed in the shallow waters around East Asian countries. We investigated the effect of G. amansii on lipid accumulation and ROS (Reactive Oxygen Species) production in 3T3-L1 cells. G. amansii extracts dose-dependently inhibited lipid formation and ROS generation in cultured cells. Our results showed that anti-adipogenic effect of G. amansii was due to the reduction in mRNA expressions of PPARγ peroxisome proliferator-activated receptor-γ and aP2 (adipocyte protein 2). G. amansii extracts significantly decreased mRNA levels of a ROS-generator, NOX4 (nicotinamide adenine dinucleotide phosphate hydrogen oxidase 4), and increased the protein levels of antioxidant enzymes including SOD1/2 (superoxide dis-mutases), Gpx (glutathione peroxidase), and GR (glutathione reductase), which can lead to the reduction of ROS in the cell. In addition, the G. amansii extract enhanced mRNA levels of adiponectin, one of the adipokines secreted from adipocytes, and GLUT4, glucose uptake protein. Taken together, our study shows that G. amansii extract inhibited lipid accumulation and ROS production by controlling adipogenic signals and ROS regulating genes.

Observation of small sub-pulses out of the delayed-interference signal-wavelength converter

DEFF Research Database (Denmark)

Sakaguchi, J.; Nielsen, Mads Lønstrup; Ohira, T.

2005-01-01

The generation of small sub-pulses in the delayed-interference signal-wavelength converter (DISC), which has been studied for use in future 160-Gb/s optical time division multiplexing-wavelength division multiplexing (OTDM-WDM) communication systems, was recently predicted as a potential problem....... In this work, we have experimentally verified the generation of such pulses and its mechanism. In the experiments we used 3.8-ps-long 1.56-mu m input pulses with repetition frequencies from 12.5 to 25.0 GHz and a cross-correlation monitoring system with a time resolution of approximately 2 ps....

Group Delay of High Q Antennas

DEFF Research Database (Denmark)

Bahramzy, Pevand; Pedersen, Gert Frølund

2013-01-01

Group Delay variations versus frequency is an essential factor which can cause distortion and degradation in the signals. Usually this is an issue in wideband communication systems, such as satellite communication systems, which are used for transmitting wideband data. However, group delay can also...... become an issue, when working with high Q antennas, because of the steep phase shift over the frequency. In this paper, it is measured how large group delay variations can become, when going from a low Q antenna to a high Q antenna. The group delay of a low Q antenna is shown to be around 1.3 ns, whereas...... a high Q antenna has group delay of around 22 ns. It is due to this huge group delay variation characteristics of high Q antennas, that signal distortion might occur in the radio system with high Q antennas....

Reactive Oxygen Species Generation-Scavenging and Signaling during Plant-Arbuscular Mycorrhizal and Piriformospora indica Interaction under Stress Condition.

Science.gov (United States)

Nath, Manoj; Bhatt, Deepesh; Prasad, Ram; Gill, Sarvajeet S; Anjum, Naser A; Tuteja, Narendra

2016-01-01

A defined balance between the generation and scavenging of reactive oxygen species (ROS) is essential to utilize ROS as an adaptive defense response of plants under biotic and abiotic stress conditions. Moreover, ROS are not only a major determinant of stress response but also act as signaling molecule that regulates various cellular processes including plant-microbe interaction. In particular, rhizosphere constitutes the biologically dynamic zone for plant-microbe interactions which forms a mutual link leading to reciprocal signaling in both the partners. Among plant-microbe interactions, symbiotic associations of arbuscular mycorrhizal fungi (AMF) and arbuscular mycorrhizal-like fungus especially Piriformospora indica with plants are well known to improve plant growth by alleviating the stress-impacts and consequently enhance the plant fitness. AMF and P. indica colonization mainly enhances ROS-metabolism, maintains ROS-homeostasis, and thereby averts higher ROS-level accrued inhibition in plant cellular processes and plant growth and survival under stressful environments. This article summarizes the major outcomes of the recent reports on the ROS-generation, scavenging and signaling in biotic-abiotic stressed plants with AMF and P. indica colonization. Overall, a detailed exploration of ROS-signature kinetics during plant-AMF/ P. indica interaction can help in designing innovative strategies for improving plant health and productivity under stress conditions.

Clinical and pathological significance of ROS1 expression in intrahepatic cholangiocarcinoma

International Nuclear Information System (INIS)

Lee, Kyung-Hun; Lee, Kyoung-Bun; Kim, Tae-Yong; Han, Sae-Won; Oh, Do-Youn; Im, Seock-Ah; Kim, Tae-You; Yi, Nam-Joon; Lee, Kwang-Woong; Suh, Kyung-Suk; Jang, Ja-June; Bang, Yung-Jue

2015-01-01

More knowledge about genetic and molecular features of cholangiocarcinoma is needed to develop effective therapeutic strategies. We investigated the clinical and pathological significance of ROS1 expression in intrahepatic cholangiocarcinoma. One hundred ninety-four patients with curatively resected intrahepatic cholangiocarcinoma were included in this study. Tumor tissue specimens were collected and analyzed for ROS1 gene rearrangement using fluorescence in situ hybridization (FISH) and ROS1 protein expression using immunohistochemistry (IHC). ROS1 immunohistochemistry was positive (moderate or strong staining) in 72 tumors (37.1 %). ROS1 protein expression was significantly correlated with well differentiated tumors, papillary or mucinous histology, oncocytic/hepatoid or intestinal type tumors, and periductal infiltrating or intraductal growing tumors (vs. mass-forming cholangiocarcinoma). ROS-expressing tumors were associated with better disease-free survival (30.1 months for ROS1 expression (+) tumors vs. 9.0 months for ROS1 (−) tumors, p = 0.006). Moreover, ROS1 expression was an independent predictor of better disease-free survival in a multivariate analysis (HR 0.607, 95 % CI 0.377–0.976; p = 0.039). Although break-apart FISH was successfully performed in 102 samples, a split pattern indicative of ROS1 gene rearrangement was not found in the examined samples. ROS1 protein expression was associated with well-differentiated histology and better survival in our patients with resected intrahepatic cholangiocarcinoma. ROS1 gene rearrangement by break-apart FISH was not found in the examined samples

CCR-2 neutralization augments murine fresh BMC activation by Staphylococcus aureus via two distinct mechanisms: at the level of ROS production and cytokine response.

Science.gov (United States)

Nandi, Ajeya; Bishayi, Biswadev

2017-05-01

CCR-2 signaling regulates recruitment of monocytes from the bone marrow into the bloodstream and then to sites of infection. We sought to determine whether CCL-2/CCR-2 signaling is involved in the killing of Staphylococcus aureus by murine bone marrow cells (BMCs). The intermittent link of reactive oxygen species (ROS)-NF-κB/p38-MAPK-mediated CCL-2 production in CCR-2 signaling prompted us to determine whether neutralization of CCR-2 augments the response of murine fresh BMCs (FBMCs) after S. aureus infection. It was observed that anti-CCR-2 Ab-treated FBMCs released fewer ROS on encountering S. aureus infection than CCR-2 non-neutralized FBMCs, also correlating with reduced killing of S. aureus in CCR-2 neutralized FBMCs. Staphylococcal catalase and SOD were also found to play a role in protecting S. aureus from the ROS-mediated killing of FBMC. S. aureus infection of CCR-2 intact FBMCs pre-treated with either NF-κB or p-38-MAPK blocker induced less CCL-2, suggesting that NF-κB or p-38-MAPK is required for CCL-2 production by FBMCs. Moreover, blocking of CCR-2 along with NF-κB or p-38-MAPK resulted in elevated CCL-2 production and reduced CCR-2 expression. Inhibition of CCR-2 impairs the response of murine BMCs to S. aureus infection by attenuation ROS production and modulating the cytokine response.

Inhibiting ROS-TFEB-Dependent Autophagy Enhances Salidroside-Induced Apoptosis in Human Chondrosarcoma Cells.

Science.gov (United States)

Zeng, Wei; Xiao, Tao; Cai, Anlie; Cai, Weiliang; Liu, Huanhuan; Liu, Jingling; Li, Jie; Tan, Miduo; Xie, Li; Liu, Ying; Yang, Xiangcheng; Long, Yi

2017-01-01

Autophagy modulation has been considered a potential therapeutic strategy for human chondrosarcoma, and a previous study indicated that salidroside exhibits significant anti-carcinogenic activity. However, the ability of salidroside to induce autophagy and its role in human chondrosarcoma cell death remains unclear. We exposed SW1353 cells to different concentrations of salidroside (0.5, 1 and 2 mM) for 24 h. RT-PCR, Western-blotting, Immunocytofluorescence, and Luciferase Reporter Assays were used to evaluate whether salidroside activated the TFEB-dependent autophagy. We show that salidroside induced significant apoptosis in the human chondrosarcoma cell line SW1353. In addition, we demonstrate that salidroside-induced an autophagic response in SW1353 cells, as evidenced by the upregulation of LC3-II and downregulation of P62. Moreover, pharmacological or genetic blocking of autophagy enhanced salidroside -induced apoptosis, indicating the cytoprotective role of autophagy in salidroside-treated SW1353 cells. Salidroside also induced TFEB (Ser142) dephosphorylation, subsequently to activated TFEB nuclear translocation and increase of TFEB reporter activity, which contributed to lysosomal biogenesis and the expression of autophagy-related genes. Importantly, we found that salidroside triggered the generation of ROS in SW1353 cells. Furthermore, NAC, a ROS scavenger, abrogated the effects of salidroside on TFEB-dependent autophagy. These data demonstrate that salidroside increased TFEB-dependent autophagy by activating ROS signaling pathways in human chondrosarcoma cells. These data also suggest that blocking ROS-TFEB-dependent autophagy to enhance the activity of salidroside warrants further attention in treatment of human chondrosarcoma cells. © 2017 The Author(s). Published by S. Karger AG, Basel.

Time Delay Estimation Algoritms for Echo Cancellation

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Kirill Sakhnov

2011-01-01

Full Text Available The following case study describes how to eliminate echo in a VoIP network using delay estimation algorithms. It is known that echo with long transmission delays becomes more noticeable to users. Thus, time delay estimation, as a part of echo cancellation, is an important topic during transmission of voice signals over packetswitching telecommunication systems. An echo delay problem associated with IP-based transport networks is discussed in the following text. The paper introduces the comparative study of time delay estimation algorithm, used for estimation of the true time delay between two speech signals. Experimental results of MATLab simulations that describe the performance of several methods based on cross-correlation, normalized crosscorrelation and generalized cross-correlation are also presented in the paper.

Delay 25 an ASIC for timing adjustment in LHC

NARCIS (Netherlands)

Furtado, H.; Schrader, J.H.R.; Marchioro, A.; Moreira, P.

A five channel programmable delay line ASIC was designed featuring 4 channels that allow to phase delay periodic or non-periodic digital signals and a master channel that can be used to phase delay a clock signal. The master channel serves as a calibration reference guaranteeing independence from

NADPH oxidase-2 derived ROS dictates murine DC cytokine-mediated cell fate decisions during CD4 T helper-cell commitment.

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Meghan A Jendrysik

Full Text Available NADPH oxidase-2 (Nox2/gp91(phox and p47(phox deficient mice are prone to hyper-inflammatory responses suggesting a paradoxical role for Nox2-derived reactive oxygen species (ROS as anti-inflammatory mediators. The molecular basis for this mode of control remains unclear. Here we demonstrate that IFNγ/LPS matured p47(phox-/--ROS deficient mouse dendritic cells (DC secrete more IL-12p70 than similarly treated wild type DC, and in an in vitro co-culture model IFNγ/LPS matured p47(phox-/- DC bias more ovalbumin-specific CD4(+ T lymphocytes toward a Th1 phenotype than wild type (WT DC through a ROS-dependent mechanism linking IL-12p70 expression to regulation of p38-MAPK activation. The Nox2-dependent ROS production in DC negatively regulates proinflammatory IL-12 expression in DC by constraining p38-MAPK activity. Increasing endogenous H(2O(2 attenuates p38-MAPK activity in IFNγ/LPS stimulated WT and p47(phox-/- DC, which suggests that endogenous Nox 2-derived ROS functions as a secondary messenger in the activated p38-MAPK signaling pathway during IL-12 expression. These findings indicate that ROS, generated endogenously by innate and adaptive immune cells, can function as important secondary messengers that can regulate cytokine production and immune cell cross-talk to control during the inflammatory response.

Redox signaling in plants.

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Foyer, Christine H; Noctor, Graham

2013-06-01

Our aim is to deliver an authoritative and challenging perspective of current concepts in plant redox signaling, focusing particularly on the complex interface between the redox and hormone-signaling pathways that allow precise control of plant growth and defense in response to metabolic triggers and environmental constraints and cues. Plants produce significant amounts of singlet oxygen and other reactive oxygen species (ROS) as a result of photosynthetic electron transport and metabolism. Such pathways contribute to the compartment-specific redox-regulated signaling systems in plant cells that convey information to the nucleus to regulate gene expression. Like the chloroplasts and mitochondria, the apoplast-cell wall compartment makes a significant contribution to the redox signaling network, but unlike these organelles, the apoplast has a low antioxidant-buffering capacity. The respective roles of ROS, low-molecular antioxidants, redox-active proteins, and antioxidant enzymes are considered in relation to the functions of plant hormones such as salicylic acid, jasmonic acid, and auxin, in the composite control of plant growth and defense. Regulation of redox gradients between key compartments in plant cells such as those across the plasma membrane facilitates flexible and multiple faceted opportunities for redox signaling that spans the intracellular and extracellular environments. In conclusion, plants are recognized as masters of the art of redox regulation that use oxidants and antioxidants as flexible integrators of signals from metabolism and the environment.

Beyond the polymerase-γ theory: Production of ROS as a mode of NRTI-induced mitochondrial toxicity.

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Reuben L Smith

Full Text Available Use of some HIV-1 nucleoside reverse transcriptase inhibitors (NRTI is associated with severe adverse events. However, the exact mechanisms behind their toxicity has not been fully understood. Mitochondrial dysfunction after chronic exposure to specific NRTIs has predominantly been assigned to mitochondrial polymerase-γ inhibition by NRTIs. However, an increasing amount of data suggests that this is not the sole mechanism. Many NRTI induced adverse events have been linked to the incurrence of oxidative stress, although the causality of events leading to reactive oxygen species (ROS production and their role in toxicity is unclear. In this study we show that short-term effects of first generation NRTIs, which are rarely discussed in the literature, include inhibition of oxygen consumption, decreased ATP levels and increased ROS production. Collectively these events affect fitness and longevity of C. elegans through mitohormetic signalling events. Furthermore, we demonstrate that these effects can be normalized by addition of the anti-oxidant N-acetylcysteine (NAC, which suggests that ROS likely influence the onset and severity of adverse events upon drug exposure.

Optical resonators for true-time-delay beam steering

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Gesell, Leslie H.; Evanko, Stephen M.

1996-06-01

Conventional true time delay beamforming and steering devices rely on switching between various lengths of delay line. Therefore only discrete delays are possible. Proposed is a new photonics concept for true time delay beamforming which provides a finely controlled continuum of delays with switching speeds on the order of 10's of nanoseconds or faster. The architecture uses an array of waveguide cavities with different resonate frequencies to channelize the signal. Each spectral component of the signal is phase shifted by an amount proportional to the frequency of that component and the desired time delay. These phase shifted spectral components are then summed to obtain the delayed signal. This paper provides an overview of the results of a Phase I SBIR contract where this concept has been refined and analyzed. The parameters for an operational system are determined and indication of the feasibility of this approach is given. Among the issues addressed are the requirements of the resonators and the methods necessary to implement fiber optic Bragg gratings as these resonators.

JNDS of interaural time delay (ITD) of selected frequency bands in speech and music signals

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Aliphas, Avner; Colburn, H. Steven; Ghitza, Oded

2002-05-01

JNDS of interaural time delay (ITD) of selected frequency bands in the presence of other frequency bands have been reported for noiseband stimuli [Zurek (1985); Trahiotis and Bernstein (1990)]. Similar measurements will be reported for speech and music signals. When stimuli are synthesized with bandpass/band-stop operations, performance with complex stimuli are similar to noisebands (JNDS in tens or hundreds of microseconds); however, the resulting waveforms, when viewed through a model of the auditory periphery, show distortions (irregularities in phase and level) at the boundaries of the target band of frequencies. An alternate synthesis method based upon group-delay filtering operations does not show these distortions and is being used for the current measurements. Preliminary measurements indicate that when music stimuli are created using the new techniques, JNDS of ITDs are increased significantly compared to previous studies, with values on the order of milliseconds.

Arabidopsis ABI5 plays a role in regulating ROS homeostasis by activating CATALASE 1 transcription in seed germination.

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Bi, Chao; Ma, Yu; Wu, Zhen; Yu, Yong-Tao; Liang, Shan; Lu, Kai; Wang, Xiao-Fang

2017-05-01

It has been known that ABA INSENSITIVE 5 (ABI5) plays a vital role in regulating seed germination. In the present study, we showed that inhibition of the catalase activity with 3-amino-1,2,4-triazole (3-AT) inhibits seed germination of Col-0, abi5 mutants and ABI5-overexpression transgenic lines. Compared with Col-0, the seeds of abi5 mutants showed more sensitive to 3-AT during seed germination, while the seeds of ABI5-overexpression transgenic lines showed more insensitive. H 2 O 2 showed the same effect on seed germination of Col-0, abi5 mutants and ABI5-overexpression transgenic lines as 3-AT. These results suggest that ROS is involved in the seed germination mediated by ABI5. Further, we observed that T-DNA insertion mutants of the three catalase members in Arabidopsis displayed 3-AT-insensitive or -hypersensitive phenotypes during seed germination, suggesting that these catalase members regulate ROS homeostasis in a highly complex way. ABI5 affects reactive oxygen species (ROS) homeostasis by affecting CATALASE expression and catalase activity. Furthermore, we showed that ABI5 directly binds to the CAT1 promoter and activates CAT1 expression. Genetic evidence supports the idea that CAT1 functions downstream of ABI5 in ROS signaling during seed germination. RNA-sequencing analysis indicates that the transcription of the genes involved in ROS metabolic process or genes responsive to ROS stress is impaired in abi5-1 seeds. Additionally, expression changes in some genes correlative to seed germination were showed due to the change in ABI5 expression under 3-AT treatment. Together, all the findings suggest that ABI5 regulates seed germination at least partly by affecting ROS homeostasis.

Tapetal-Delayed Programmed Cell Death (PCD and Oxidative Stress-Induced Male Sterility of Aegilops uniaristata Cytoplasm in Wheat

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Zihan Liu

2018-06-01

Full Text Available Cytoplasmic male sterility (CMS plays a crucial role in the utilization of hybrid vigor. Pollen development is often accompanied by oxidative metabolism responses and tapetal programmed cell death (PCD, and deficiency in these processes could lead to male sterility. Aegilops uniaristata cytoplasmic male sterility (Mu-CMS wheat is a novel male-sterile line in wheat, which possess important potential in hybrid wheat breeding. However, its CMS mechanisms remain poorly understood. In our study, U87B1-706A, with the Aegilops uniaristata cytoplasm, and the maintainer line 706B were used to explore the abortive reason. Compared with 706B, histological analysis and PCD detection of the anther demonstrated that U87B1-706A appeared as delayed tapetal PCD as well as a disorganized organelle phenotype in the early uninucleate stage. Subsequently, a shrunken microspore and disordered exine structure were exhibited in the late uninucleate stage. While the activities of antioxidase increased markedly, the nonenzymatic antioxidant contents declined obviously following overacummulation of reactive oxygen species (ROS during pollen development in U87B1-706A. Real-time quantitative PCR testified that the transcript levels of the superoxide dismutase (SOD, catalase (CAT, and ascorbate peroxidase (APX genes, encoding pivotal antioxidant enzymes, were up-regulated in early pollen development. Therefore, we deduce excess ROS as a signal may be related to the increased expression levels of enzyme genes, thereby breaking the antioxidative system balance, resulting in delayed tapetal PCD initiation, which finally led to pollen abortion and male sterility in U87B1-706A. These results provide evidence to further explore the mechanisms of abortive pollen in CMS wheat.

YARP-ROS Inter-Operation in a 2D Navigation Task

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Marco Randazzo

2018-02-01

Full Text Available This paper presents some recent developments in YARP middleware, aimed to improve its integration with ROS. They include a new mechanism to read/write ROS transform frames and a new set of standard interfaces to intercommunicate with the ROS navigation stack. A novel set of YARP companion modules, which provide basic navigation functionalities for robots unable to run ROS, is also presented. These modules are optional, independent from each other, and they provide compatible functionalities to well-known packages available inside ROS framework. This paper also discusses how developers can customize their own hybrid YARP-ROS environment in the way it best suits their needs (e.g., the system can be configured to have a YARP application sending navigation commands to a ROS path planner, or vice versa. A number of available possibilities is presented through a set of chosen test cases applied to both real and simulated robots. Finally, example applications discussed in this paper are also made available to the community by providing snippets of code and links to source files hosted on github repository https://github.com/robotology.1

ROS-mediated inhibition of S-nitrosoglutathione reductase contributes to the activation of anti-oxidative mechanisms

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Izabella Kovacs

2016-11-01

Full Text Available Nitric oxide (NO has emerged as a signaling molecule in plants being involved in diverse physiological processes like germination, root growth, stomata closing and response to biotic and abiotic stress. S-nitrosoglutathione (GSNO as a biological NO donor has a very important function in NO signaling since it can transfer its NO moiety to other proteins (trans-nitrosylation. Such trans-nitrosylation reactions are equilibrium reactions and depend on GSNO level. The breakdown of GSNO and thus the level of S-nitrosylated proteins are regulated by GSNO-reductase (GSNOR. In this way, this enzyme controls S-nitrosothiol levels and regulates NO signaling. Here we report that Arabidopsis thaliana GSNOR activity is reversibly inhibited by H2O2 in-vitro and by paraquat-induced oxidative stress in-vivo. Light scattering analyses of reduced and oxidized recombinant GSNOR demonstrated that GSNOR proteins form dimers under both reducing and oxidizing conditions. Moreover, mass spectrometric analyses revealed that H2O2-treatment increased the amount of oxidative modifications on Zn2+-coordinating Cys47 and Cys177. Inhibition of GSNOR results in enhanced levels of S-nitrosothiols followed by accumulation of glutathione. Moreover, transcript levels of redox-regulated genes and activities of glutathione-dependent enzymes are increased in gsnor-ko plants, which may contribute to the enhanced resistance against oxidative stress. In sum, our results demonstrate that ROS-dependent inhibition of GSNOR is playing an important role in activation of anti-oxidative mechanisms to damping oxidative damage and imply a direct crosstalk between ROS- and NO-signaling.

MicroRNA-145 suppresses ROS-induced Ca2+ overload of cardiomyocytes by targeting CaMKIIδ

International Nuclear Information System (INIS)

Cha, Min-Ji; Jang, Jin-Kyung; Ham, Onju; Song, Byeong-Wook; Lee, Se-Yeon; Lee, Chang Yeon; Park, Jun-Hee; Lee, Jiyun; Seo, Hyang-Hee; Choi, Eunhyun; Jeon, Woo-min; Hwang, Hye Jin; Shin, Hyun-Taek

2013-01-01

Highlights: •CaMKIIδ mediates H 2 O 2 -induced Ca 2+ overload in cardiomyocytes. •miR-145 can inhibit Ca 2+ overload. •A luciferase assay confirms that miR-145 functions as a CaMKIIδ-targeting miRNA. •Overexpression of miR-145 regulates CaMKIIδ-related genes and ameliorates apoptosis. -- Abstract: A change in intracellular free calcium (Ca 2+ ) is a common signaling mechanism of reperfusion-induced cardiomyocyte death. Calcium/calmodulin dependent protein kinase II (CaMKII) is a critical regulator of Ca 2+ signaling and mediates signaling pathways responsible for functions in the heart including hypertrophy, apoptosis, arrhythmia, and heart disease. MicroRNAs (miRNA) are involved in the regulation of cell response, including survival, proliferation, apoptosis, and development. However, the roles of miRNAs in Ca 2+ -mediated apoptosis of cardiomyocytes are uncertain. Here, we determined the potential role of miRNA in the regulation of CaMKII dependent apoptosis and explored its underlying mechanism. To determine the potential roles of miRNAs in H 2 O 2 -mediated Ca 2+ overload, we selected and tested 6 putative miRNAs that targeted CaMKIIδ, and showed that miR-145 represses CaMKIIδ protein expression and Ca 2+ overload. We confirmed CaMKIIδ as a direct downstream target of miR-145. Furthermore, miR-145 regulates Ca 2+ -related signals and ameliorates apoptosis. This study demonstrates that miR-145 regulates reactive oxygen species (ROS)-induced Ca 2+ overload in cardiomyocytes. Thus, miR-145 affects ROS-mediated gene regulation and cellular injury responses

Duration reproduction with sensory feedback delay: Differential involvement of perception and action time

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Stephanie eGanzenmüller

2012-10-01

Full Text Available Previous research has shown that voluntary action can attract subsequent, delayed feedback events towards the action, and adaptation to the sensorimotor delay can even reverse motor-sensory temporal-order judgments. However, whether and how sensorimotor delay affects duration reproduction is still unclear. To investigate this, we injected an onset- or offset-delay to the sensory feedback signal from a duration reproduction task. We compared duration reproductions within (visual, auditory modality and across audiovisual modalities with feedback signal onset- and offset-delay manipulations. We found that the reproduced duration was lengthened in both visual and auditory feedback signal onset-delay conditions. The lengthening effect was evident immediately, on the first trial with the onset delay. However, when the onset of the feedback signal was prior to the action, the lengthening effect was diminished. In contrast, a shortening effect was found with feedback signal offset-delay, though the effect was weaker and manifested only in the auditory offset-delay condition. These findings indicate that participants tend to mix the onset of action and the feedback signal more when the feedback is delayed, and they heavily rely on motor-stop signals for the duration reproduction. Furthermore, auditory duration was overestimated compared to visual duration in crossmodal feedback conditions, and the overestimation of auditory duration (or the underestimation of visual duration was independent of the delay manipulation.

Inter-electrode delay estimators for electrohysterographic propagation analysis

International Nuclear Information System (INIS)

Rabotti, Chiara; Mischi, Massimo; Bergmans, Jan W M; Van Laar, Judith O E H; Oei, Guid S

2009-01-01

Premature birth is a major cause of mortality and permanent dysfunctions. Several parameters derived from single channel electrohysterographic (EHG) signals have been considered to determine contractions leading to preterm delivery. The results are promising, but improvements are needed. As effective uterine contractions result from a proper action potential propagation, in this paper we focus on the propagation properties of EHG signals, which can be predictive of preterm delivery. Two standard delay estimators, namely maximization of the cross-correlation function and spectral matching, are adapted and implemented for the assessment of inter-electrode delays of propagating EHG signals. The accuracy of the considered standard estimators might be hampered by a poor inter-channel correlation. An improved dedicated approach is therefore proposed. By simultaneous adaptive estimation of the volume conductor transfer function and the delay, a dedicated method is conceived for improving the inter-channel signal similarity during delay calculation. Furthermore, it provides delay estimates without resolution limits and it is suitable for low sampling rates, which are appropriate for EHG recording. The three estimators were evaluated on EHG signals recorded on seven women. The dedicated approach provided more accurate estimates due to a 22% improvement of the initial average inter-channel correlation

Reactive oxygen species activate differentiation gene transcription of acute myeloid leukemia cells via the JNK/c-JUN signaling pathway.

Science.gov (United States)

Lam, Chung Fan; Yeung, Hoi Ting; Lam, Yuk Man; Ng, Ray Kit

2018-05-01

Reactive oxygen species (ROS) and altered cellular redox status are associated with many malignancies. Acute myeloid leukemia (AML) cells are maintained at immature state by differentiation blockade, which involves deregulation of transcription factors in myeloid differentiation. AML cells can be induced to differentiate by phorbol-12-myristate-13-acetate (PMA), which possesses pro-oxidative activity. However, the signaling events mediated by ROS in the activation of transcriptional program during AML differentiation has not been fully elucidated. Here, we investigated AML cell differentiation by treatment with PMA and ROS scavenger N-acetyl-l-cysteine (NAC). We observed elevation of intracellular ROS level in the PMA-treated AML cells, which correlated with differentiated cell morphology and increased CD11b + mature cell population. The effect of PMA can be abolished by NAC co-treatment, supporting the involvement of ROS in the process. Moreover, we demonstrated that short ROS elevation mediated cell cycle arrest, but failed to activate myeloid gene transcription; whereas prolonged ROS elevation activated JNK/c-JUN signaling pathway. Inhibition of JNK suppressed the expression of key myeloid transcriptional regulators c-JUN, SPI-1 and MAFB, and prevented AML cells from undergoing terminal differentiation. These findings provide new insights into the crucial role of JNK/c-Jun signaling pathway in the activation of transcriptional program during ROS-mediated AML differentiation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Redox Signaling in Skeletal Muscle: Role of Aging and Exercise

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Ji, Li Li

2015-01-01

Skeletal muscle contraction is associated with the production of ROS due to altered O[subscript 2] distribution and flux in the cell. Despite a highly efficient antioxidant defense, a small surplus of ROS, such as hydrogen peroxide and nitric oxide, may serve as signaling molecules to stimulate cellular adaptation to reach new homeostasis largely…

Targeted Modification of Mitochondrial ROS Production Converts High Glucose-Induced Cytotoxicity to Cytoprotection: Effects on Anesthetic Preconditioning.

Science.gov (United States)

Sedlic, Filip; Muravyeva, Maria Y; Sepac, Ana; Sedlic, Marija; Williams, Anna Marie; Yang, Meiying; Bai, Xiaowen; Bosnjak, Zeljko J

2017-01-01

Contradictory reports on the effects of diabetes and hyperglycemia on myocardial infarction range from cytotoxicity to cytoprotection. The study was designed to investigate acute effects of high glucose-driven changes in mitochondrial metabolism and osmolarity on adaptive mechanisms and resistance to oxidative stress of isolated rat cardiomyocytes. We examined the effects of high glucose on several parameters of mitochondrial bioenergetics, including changes in oxygen consumption, mitochondrial membrane potential, and NAD(P)H fluorometry. Effects of high glucose on the endogenous cytoprotective mechanisms elicited by anesthetic preconditioning (APC) and the mediators of cell injury were also tested. These experiments included real-time measurements of reactive oxygen species (ROS) production and mitochondrial permeability transition pore (mPTP) opening in single cells by laser scanning fluorescence confocal microscopy, and cell survival assay. High glucose rapidly enhanced mitochondrial energy metabolism, observed by increase in NAD(P)H fluorescence intensity, oxygen consumption, and mitochondrial membrane potential. This substantially elevated production of ROS, accelerated opening of the mPTP, and decreased survival of cells exposed to oxidative stress. Abrogation of high glucose-induced mitochondrial hyperpolarization with 2,4 dinitrophenol (DNP) significantly, but not completely, attenuated ROS production to a level similar to hyperosmotic mannitol control. DNP treatment reversed high glucose-induced cytotoxicity to cytoprotection. Hyperosmotic mannitol treatment also induced cytoprotection. High glucose abrogated APC-induced mitochondrial depolarization, delay in mPTP opening and cytoprotection. In conclusion, high glucose-induced mitochondrial hyperpolarization abolishes APC and augments cell injury. Attenuation of high glucose-induced ROS production by eliminating mitochondrial hyperpolarization protects cardiomyocytes. J. Cell. Physiol. 232: 216-224, 2017

Middleware Interoperability for Robotics: A ROS-YARP Framework

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Plinio Moreno

2016-10-01

Full Text Available Middlewares are fundamental tools for progress in research and applications in robotics. They enable the integration of multiple heterogeneous sensing and actuation devices, as well as providing general purpose modules for key robotics functions (kinematics, navigation, planning. However, no existing middleware yet provides a complete set of functionalities for all robotics applications, and many robots may need to rely on more than one framework. This paper focuses on the interoperability between two of the most prevalent middleware in robotics: YARP and ROS. Interoperability between middlewares should ideally allow users to execute existing software without the necessity of: (i changing the existing code, and (ii writing hand-coded ``bridges'' for each use-case. We propose a framework enabling the communication between existing YARP modules and ROS nodes for robotics applications in an automated way. Our approach generates the ``bridging gap'' code from a configuration file, connecting YARP ports and ROS topics through code-generated YARP Bottles. %%The configuration file must describe: (i the sender entities, (ii the way to group and convert the information read from the sender, (iii the structure of the output message and (iv the receiving entity. Our choice for the many inputs to one output is the most common use-case in robotics applications, where examples include filtering, decision making and visualization. %We support YARP/ROS and ROS/YARP sender/receiver configurations, which are demonstrated in a humanoid on wheels robot that uses YARP for upper body motor control and visual perception, and ROS for mobile base control and navigation algorithms.

Behavioral effects of delayed timeouts from reinforcement.

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Byrne, Tom; Poling, Alan

2017-03-01

Timeouts are sometimes used in applied settings to reduce target responses, and in some circumstances delays are unavoidably imposed between the onset of a timeout and the offset of the response that produces it. The present study examined the effects of signaled and unsignaled timeouts in rats exposed to concurrent fixed-ratio 1 fixed-ratio 1 schedules of food delivery, where each response on one lever, the location of which changed across conditions, produced both food and a delayed 10-s timeout. Delays of 0 to 38 s were examined. Delayed timeouts often, but not always, substantially reduced the number of responses emitted on the lever that produced timeouts relative to the number emitted on the lever that did not produce timeouts. In general, greater sensitivity was observed to delayed timeouts when they were signaled. These results demonstrate that delayed timeouts, like other delayed consequences, can affect behavior, albeit less strongly than immediate consequences. © 2017 Society for the Experimental Analysis of Behavior.

Cadmium-induced glutathionylation of actin occurs through a ROS-independent mechanism: Implications for cytoskeletal integrity

Energy Technology Data Exchange (ETDEWEB)

Choong, Grace; Liu, Ying; Xiao, Weiqun; Templeton, Douglas M., E-mail: doug.templeton@utoronto.ca

2013-10-15

Cadmium disrupts the actin cytoskeleton in rat mesangial cells, and we have previously shown that this involves a complex interplay involving activation of kinase signaling, protein translocation, and disruption of focal adhesions. Here we investigate the role that glutathionylation of actin plays in Cd{sup 2+}-associated cytoskeletal reorganization. Low concentrations of Cd{sup 2+} (0.5–2 μM) caused an increase in actin glutathionylation by 6 h, whereas at higher concentrations glutathionylation remained at basal levels. Although oxidation with diamide increased glutathionylation, reactive oxygen species (ROS) were not involved in the Cd{sup 2+}-dependent effect, as only Cd{sup 2+} concentrations above 2 μM were sufficient to increase ROS. However, low [Cd{sup 2+}] increased total glutathione levels without affecting the ratio of reduced/oxidized glutathione, and inhibition of glutathione synthesis suppressed actin glutathionylation. Cadmium increased the activity of the enzyme glutaredoxin, which influences the equilibrium between glutathionylated and deglutathionylated proteins and thus may influence levels of glutathionylated actin. Together these observations show that cadmium-dependent effects on actin glutathionylation are affected by glutathione metabolism and not by direct effects of ROS on thiol chemistry. In vitro polymerization assays with glutathionylated actin show a decreased rate of polymerization. In contrast, immunofluorescence of cytoskeletal structure in intact cells suggests that increases in actin glutathionylation accompanying increased glutathione levels occurring under low Cd{sup 2+} exposure are protective in vivo, with cytoskeletal disruption ensuing only when higher Cd{sup 2+} concentrations increase ROS levels and prevent an increase in actin–glutathione conjugates. - Highlights: • Cadmium disrupts the actin cytoskeleton in mesangial cells. • Cadmium induces glutathionylation of actin at low concentrations. �

Cadmium-induced glutathionylation of actin occurs through a ROS-independent mechanism: Implications for cytoskeletal integrity

International Nuclear Information System (INIS)

Choong, Grace; Liu, Ying; Xiao, Weiqun; Templeton, Douglas M.

2013-01-01

Cadmium disrupts the actin cytoskeleton in rat mesangial cells, and we have previously shown that this involves a complex interplay involving activation of kinase signaling, protein translocation, and disruption of focal adhesions. Here we investigate the role that glutathionylation of actin plays in Cd 2+ -associated cytoskeletal reorganization. Low concentrations of Cd 2+ (0.5–2 μM) caused an increase in actin glutathionylation by 6 h, whereas at higher concentrations glutathionylation remained at basal levels. Although oxidation with diamide increased glutathionylation, reactive oxygen species (ROS) were not involved in the Cd 2+ -dependent effect, as only Cd 2+ concentrations above 2 μM were sufficient to increase ROS. However, low [Cd 2+ ] increased total glutathione levels without affecting the ratio of reduced/oxidized glutathione, and inhibition of glutathione synthesis suppressed actin glutathionylation. Cadmium increased the activity of the enzyme glutaredoxin, which influences the equilibrium between glutathionylated and deglutathionylated proteins and thus may influence levels of glutathionylated actin. Together these observations show that cadmium-dependent effects on actin glutathionylation are affected by glutathione metabolism and not by direct effects of ROS on thiol chemistry. In vitro polymerization assays with glutathionylated actin show a decreased rate of polymerization. In contrast, immunofluorescence of cytoskeletal structure in intact cells suggests that increases in actin glutathionylation accompanying increased glutathione levels occurring under low Cd 2+ exposure are protective in vivo, with cytoskeletal disruption ensuing only when higher Cd 2+ concentrations increase ROS levels and prevent an increase in actin–glutathione conjugates. - Highlights: • Cadmium disrupts the actin cytoskeleton in mesangial cells. • Cadmium induces glutathionylation of actin at low concentrations. • Glutathionylation requires glutathione

Generation of wideband chaos with suppressed time-delay signature by delayed self-interference.

Science.gov (United States)

Wang, Anbang; Yang, Yibiao; Wang, Bingjie; Zhang, Beibei; Li, Lei; Wang, Yuncai

2013-04-08

We demonstrate experimentally and numerically a method using the incoherent delayed self-interference (DSI) of chaotic light from a semiconductor laser with optical feedback to generate wideband chaotic signal. The results show that, the DSI can eliminate the domination of laser relaxation oscillation existing in the chaotic laser light and therefore flatten and widen the power spectrum. Furthermore, the DSI depresses the time-delay signature induced by external cavity modes and improves the symmetry of probability distribution by more than one magnitude. We also experimentally show that this DSI signal is beneficial to the random number generation.

Ethanol stimulates ROS generation by mitochondria through Ca2+ mobilization and increases GFAP content in rat hippocampal astrocytes.

Science.gov (United States)

González, Antonio; Pariente, José A; Salido, Ginés M

2007-10-31

We have employed rat hippocampal astrocytes in culture to investigate the effect of ethanol on reactive oxygen species (ROS) production as well as its effect on [Ca2+]c and GFAP expression. Cells were loaded with the fluorescent probes fura-2 and H2DCFDA for the determination of changes in [Ca2+]c and ROS production respectively, employing spectrofluorimetry. GFAP content was determined by immunocytochemistry and confocal scanning microscopy. Our results show ROS production in response to 50 mM ethanol, that was reduced in Ca2+-free medium (containing 0.5 mM EGTA) and in the presence of the intracellular Ca2+ chelator BAPTA (10 microM). The effect of ethanol on ROS production was significantly reduced in the presence of the alcohol dehydrogenase inhibitor 4-methylpyrazole (1 mM), and the antioxidants resveratrol (100 microM) or catalase (300 U/ml). Preincubation of astrocytes in the presence of 10 microM antimycin plus 10 microM oligomycin to inhibit mitochondria completely blocked ethanol-evoked ROS production. In addition, ethanol led to a sustained increase in [Ca2+]c that reached a constant level over the prestimulation values. Finally, incubation of astrocytes in the presence of ethanol increased the content of GFAP that was significantly reduced in the absence of extracellular Ca2+ and by resveratrol and catalase pretreatment. The data obtained in the present study suggest that astrocytes are able to metabolize ethanol, which induces two effects on intracellular homeostasis: an immediate response (Ca2+ release and ROS generation) and later changes involving GFAP expression. Both effects may underline various signaling pathways which are important for cell proliferation, differentiation and function.

The Role of Reactive Oxygen Species in β-Adrenergic Signaling in Cardiomyocytes from Mice with the Metabolic Syndrome.

Directory of Open Access Journals (Sweden)

Monica Llano-Diez

Full Text Available The metabolic syndrome is associated with prolonged stress and hyperactivity of the sympathetic nervous system and afflicted subjects are prone to develop cardiovascular disease. Under normal conditions, the cardiomyocyte response to acute β-adrenergic stimulation partly depends on increased production of reactive oxygen species (ROS. Here we investigated the interplay between beta-adrenergic signaling, ROS and cardiac contractility using freshly isolated cardiomyocytes and whole hearts from two mouse models with the metabolic syndrome (high-fat diet and ob/ob mice. We hypothesized that cardiomyocytes of mice with the metabolic syndrome would experience excessive ROS levels that trigger cellular dysfunctions. Fluorescent dyes and confocal microscopy were used to assess mitochondrial ROS production, cellular Ca2+ handling and contractile function in freshly isolated adult cardiomyocytes. Immunofluorescence, western blot and enzyme assay were used to study protein biochemistry. Unexpectedly, our results point towards decreased cardiac ROS signaling in a stable, chronic phase of the metabolic syndrome because: β-adrenergic-induced increases in the amplitude of intracellular Ca2+ signals were insensitive to antioxidant treatment; mitochondrial ROS production showed decreased basal rate and smaller response to β-adrenergic stimulation. Moreover, control hearts and hearts with the metabolic syndrome showed similar basal levels of ROS-mediated protein modification, but only control hearts showed increases after β-adrenergic stimulation. In conclusion, in contrast to the situation in control hearts, the cardiomyocyte response to acute β-adrenergic stimulation does not involve increased mitochondrial ROS production in a stable, chronic phase of the metabolic syndrome. This can be seen as a beneficial adaptation to prevent excessive ROS levels.

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.

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.

Picosecond resolution programmable delay line

International Nuclear Information System (INIS)

Suchenek, Mariusz

2009-01-01

The note presents implementation of a programmable delay line for digital signals. The tested circuit has a subnanosecond delay range programmable with a resolution of picoseconds. Implementation of the circuit was based on low-cost components, easily available on the market. (technical design note)

A Delay Line for Compression of Electromagnetic Pulses

International Nuclear Information System (INIS)

Pchelnikov, Yuriy N.; Nyce, David S.

2003-01-01

A novel method to obtain an electromagnetic signal delay is described. It is shown that the positive magnetic and electric coupling between impedance conductors produces an increase in the time delay. It is also shown that the increase in delay time is obtained without additional attenuation. This allows a reduction in electromagnetic losses, by a factor of several times, for a delay time. An approximate analysis of electromagnetic delay lines based on coupled impedance conductors with 'spiral' and 'meander' patterns allowed obtaining very simple expressions for the wave deceleration factor, wave impedance, and attenuation factor. The results of the analysis are confirmed by the results of measurements. It is shown that a delay line based on counter-wound radial spirals can be successfully used for compression of electromagnetic pulses. Although the offered delay line was designed to operate with a relatively small signal, the analysis of the 'coupling effect', taking place in this delay line, might be useful in devices for compression of high-power microwave pulses

Spinal CPEB-mtROS-CBP signaling pathway contributes to perineural HIV gp120 with ddC-related neuropathic pain in rats.

Science.gov (United States)

Iida, Takafumi; Yi, Hyun; Liu, Shue; Huang, Wan; Kanda, Hirotsugu; Lubarsky, David A; Hao, Shuanglin

2016-07-01

Human immunodeficiency virus (HIV) patients treated with nucleoside reverse transcriptase inhibitors (NRTIs), have been known to develop neuropathic pain. While there has been a major shift away from some neurotoxic NRTIs in current antiretroviral therapy, a large number of HIV patients alive today have previously received them, and many have developed painful peripheral neuropathy. The exact mechanisms by which HIV with NRTIs contribute to the development of neuropathic pain are not known. Previous studies suggest that cytoplasmic polyadenylation element-binding protein (CPEB), reactive oxygen species (ROS), and cAMP-response element-binding protein (CREB)-binding protein (CBP), are involved in the neuroimmunological diseases including inflammatory/neuropathic pain. In this study, we investigated the role of CPEB, mitochondrial ROS (mtROS), or CBP in neuropathic pain induced by HIV envelope protein gp120 combined with antiretroviral drug. The application of recombinant gp120 into the sciatic nerve plus systemic ddC (one of NRTIs) induced mechanical allodynia. Knockdown of CPEB or CBP using intrathecal antisense oligodeoxynucleotide (AS-ODN) reduced mechanical allodynia. Intrathecal mitochondrial superoxide scavenger mito-tempol (Mito-T) increased mechanical withdrawal threshold. Knockdown of CPEB using intrathecal AS-ODN, reduced the up-regulated mitochondrial superoxide in the spinal dorsal horn in rats with gp120 combined with ddC. Intrathecal Mito-T lowered the increased expression of CBP in the spinal dorsal horn. Immunostaining studies showed that neuronal CPEB positive cells were co-localized with MitoSox positive profiles, and that MitoSox positive profiles were co-localized with neuronal CBP. Our studies suggest that neuronal CPEB-mtROS-CBP pathway in the spinal dorsal horn, plays an important role in the gp120/ddC-induced neuropathic pain in rats. Copyright © 2016. Published by Elsevier Inc.

Capsaicin Suppresses Cell Proliferation, Induces Cell Cycle Arrest and ROS Production in Bladder Cancer Cells through FOXO3a-Mediated Pathways

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Kaiyu Qian

2016-10-01

Full Text Available Capsaicin (CAP, a highly selective agonist for transient receptor potential vanilloid type 1 (TRPV1, has been widely reported to exhibit anti-oxidant, anti-inflammation and anticancer activities. Currently, several therapeutic approaches for bladder cancer (BCa are available, but accompanied by unfavorable outcomes. Previous studies reported a potential clinical effect of CAP to prevent BCa tumorigenesis. However, its underlying molecular mechanism still remains unknown. Our transcriptome analysis suggested a close link among calcium signaling pathway, cell cycle regulation, ROS metabolism and FOXO signaling pathway in BCa. In this study, several experiments were performed to investigate the effects of CAP on BCa cells (5637 and T24 and NOD/SCID mice. Our results showed that CAP could suppress BCa tumorigenesis by inhibiting its proliferation both in vitro and in vivo. Moreover, CAP induced cell cycle arrest at G0/G1 phase and ROS production. Importantly, our studies revealed a strong increase of FOXO3a after treatment with CAP. Furthermore, we observed no significant alteration of apoptosis by CAP, whereas Catalase and SOD2 were considerably upregulated, which could clear ROS and protect against cell death. Thus, our results suggested that CAP could inhibit viability and tumorigenesis of BCa possibly via FOXO3a-mediated pathways.

Time Delay of CGM Sensors

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Schmelzeisen-Redeker, Günther; Schoemaker, Michael; Kirchsteiger, Harald; Freckmann, Guido; Heinemann, Lutz; del Re, Luigi

2015-01-01

Background: Continuous glucose monitoring (CGM) is a powerful tool to support the optimization of glucose control of patients with diabetes. However, CGM systems measure glucose in interstitial fluid but not in blood. Rapid changes in one compartment are not accompanied by similar changes in the other, but follow with some delay. Such time delays hamper detection of, for example, hypoglycemic events. Our aim is to discuss the causes and extent of time delays and approaches to compensate for these. Methods: CGM data were obtained in a clinical study with 37 patients with a prototype glucose sensor. The study was divided into 5 phases over 2 years. In all, 8 patients participated in 2 phases separated by 8 months. A total number of 108 CGM data sets including raw signals were used for data analysis and were processed by statistical methods to obtain estimates of the time delay. Results: Overall mean (SD) time delay of the raw signals with respect to blood glucose was 9.5 (3.7) min, median was 9 min (interquartile range 4 min). Analysis of time delays observed in the same patients separated by 8 months suggests a patient dependent delay. No significant correlation was observed between delay and anamnestic or anthropometric data. The use of a prediction algorithm reduced the delay by 4 minutes on average. Conclusions: Prediction algorithms should be used to provide real-time CGM readings more consistent with simultaneous measurements by SMBG. Patient specificity may play an important role in improving prediction quality. PMID:26243773

SirT1 knockdown potentiates radiation-induced bystander effect through promoting c-Myc activity and thus facilitating ROS accumulation

International Nuclear Information System (INIS)

Xie, Yuexia; Tu, Wenzhi; Zhang, Jianghong; He, Mingyuan; Ye, Shuang; Dong, Chen; Shao, Chunlin

2015-01-01

Highlights: • γ-Irradiation induced bystander effects between hepatoma cells and hepatocyte cells. • SirT1 played a protective role in regulating this bystander effect. • SirT1 contributed to the protective effects via elimination the accumulation of ROS. • The activity of c-Myc is critical for maintaining the protective role of SirT1. - Abstract: Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the bystander signaling processes, especially under hypoxic condition, are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 and SK-Hep-1 cells under either normoxia or hypoxia. This bystander response was dramatically diminished or enhanced when the SirT1 gene of irradiated hepatoma cells was overexpressed or knocked down, respectively, especially under hypoxia. Meanwhile, SirT1 knockdown promoted transcriptional activity for c-Myc and facilitated ROS accumulation. But both of the increased bystander responses and ROS generation due to SirT1-knockdown were almost completely suppressed by c-Myc interference. Moreover, ROS scavenger effectively abolished the RIBE triggered by irradiated hepatoma cells even with SirT1 depletion. These findings provide new insights that SirT1 has a profound role in regulating RIBE where a c-Myc-dependent release of ROS may be involved

SirT1 knockdown potentiates radiation-induced bystander effect through promoting c-Myc activity and thus facilitating ROS accumulation

Energy Technology Data Exchange (ETDEWEB)

Xie, Yuexia [Institute of Radiation Medicine, Fudan University, Shanghai (China); Central Laboratory, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai (China); Tu, Wenzhi; Zhang, Jianghong; He, Mingyuan; Ye, Shuang; Dong, Chen [Institute of Radiation Medicine, Fudan University, Shanghai (China); Shao, Chunlin, E-mail: clshao@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, Shanghai (China)

2015-02-15

Highlights: • γ-Irradiation induced bystander effects between hepatoma cells and hepatocyte cells. • SirT1 played a protective role in regulating this bystander effect. • SirT1 contributed to the protective effects via elimination the accumulation of ROS. • The activity of c-Myc is critical for maintaining the protective role of SirT1. - Abstract: Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the bystander signaling processes, especially under hypoxic condition, are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 and SK-Hep-1 cells under either normoxia or hypoxia. This bystander response was dramatically diminished or enhanced when the SirT1 gene of irradiated hepatoma cells was overexpressed or knocked down, respectively, especially under hypoxia. Meanwhile, SirT1 knockdown promoted transcriptional activity for c-Myc and facilitated ROS accumulation. But both of the increased bystander responses and ROS generation due to SirT1-knockdown were almost completely suppressed by c-Myc interference. Moreover, ROS scavenger effectively abolished the RIBE triggered by irradiated hepatoma cells even with SirT1 depletion. These findings provide new insights that SirT1 has a profound role in regulating RIBE where a c-Myc-dependent release of ROS may be involved.

ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors.

Science.gov (United States)

Halasi, Marianna; Wang, Ming; Chavan, Tanmay S; Gaponenko, Vadim; Hay, Nissim; Gartel, Andrei L

2013-09-01

NAC (N-acetyl-L-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H₂O₂. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabilization, apoptosis and accumulation of ubiquitin conjugates. These observations suggest that NAC has a dual activity as an inhibitor of ROS and proteasome inhibitors. Recently, NAC was used as a ROS inhibitor to functionally characterize a novel anticancer compound, piperlongumine, leading to its description as a ROS inducer. In contrast, our own experiments showed that this compound depicts features of proteasome inhibitors including suppression of FOXM1 (Forkhead box protein M1), stabilization of cellular proteins, induction of ROS-independent apoptosis and enhanced accumulation of ubiquitin conjugates. In addition, NAC, but not catalase or Trolox, interfered with the activity of piperlongumine, further supporting that piperlongumine is a proteasome inhibitor. Most importantly, we showed that NAC, but not other ROS scavengers, directly binds to proteasome inhibitors. To our knowledge, NAC is the first known compound that directly interacts with and antagonizes the activity of proteasome inhibitors. Taken together, the findings of the present study suggest that, as a result of the dual nature of NAC, data interpretation might not be straightforward when NAC is utilized as an antioxidant to demonstrate ROS involvement in drug-induced apoptosis.

Programmable delay circuit for sparker signal analysis

Digital Repository Service at National Institute of Oceanography (India)

Pathak, D.

The sparker echo signal had been recorded along with the EPC recorder trigger on audio cassettes in a dual channel analog recorder. The sparker signal in the analog form had to be digitised for further signal processing techniques to be performed...

Redox regulation in photosynthetic organisms: signaling, acclimation, and practical implications.

Science.gov (United States)

Foyer, Christine H; Noctor, Graham

2009-04-01

Reactive oxygen species (ROS) have multifaceted roles in the orchestration of plant gene expression and gene-product regulation. Cellular redox homeostasis is considered to be an "integrator" of information from metabolism and the environment controlling plant growth and acclimation responses, as well as cell suicide events. The different ROS forms influence gene expression in specific and sometimes antagonistic ways. Low molecular antioxidants (e.g., ascorbate, glutathione) serve not only to limit the lifetime of the ROS signals but also to participate in an extensive range of other redox signaling and regulatory functions. In contrast to the low molecular weight antioxidants, the "redox" states of components involved in photosynthesis such as plastoquinone show rapid and often transient shifts in response to changes in light and other environmental signals. Whereas both types of "redox regulation" are intimately linked through the thioredoxin, peroxiredoxin, and pyridine nucleotide pools, they also act independently of each other to achieve overall energy balance between energy-producing and energy-utilizing pathways. This review focuses on current knowledge of the pathways of redox regulation, with discussion of the somewhat juxtaposed hypotheses of "oxidative damage" versus "oxidative signaling," within the wider context of physiological function, from plant cell biology to potential applications.

When good pigeons make bad decisions: Choice with probabilistic delays and outcomes.

Science.gov (United States)

Pisklak, Jeffrey M; McDevitt, Margaret A; Dunn, Roger M; Spetch, Marcia L

2015-11-01

Pigeons chose between an (optimal) alternative that sometimes provided food after a 10-s delay and other times after a 40-s delay and another (suboptimal) alternative that sometimes provided food after 10 s but other times no food after 40 s. When outcomes were not signaled during the delays, pigeons strongly preferred the optimal alternative. When outcomes were signaled, choices of the suboptimal alternative increased and most pigeons preferred the alternative that provided no food after the long delay despite the cost in terms of obtained food. The pattern of results was similar whether the short delays occurred on 25% or 50% of the trials. Shortening the 40-s delay to food sharply reduced suboptimal choices, but shortening the delay to no food had little effect. The results suggest that a signaled delay to no food does not punish responding in probabilistic choice procedures. The findings are discussed in terms of conditioned reinforcement by signals for good news. © Society for the Experimental Analysis of Behavior.

Mtf-1 lymphoma-susceptibility locus affects retention of large thymocytes with high ROS levels in mice after γ-irradiation

International Nuclear Information System (INIS)

Maruyama, Masaki; Yamamoto, Takashi; Kohara, Yuki; Katsuragi, Yoshinori; Mishima, Yukio; Aoyagi, Yutaka; Kominami, Ryo

2007-01-01

Mouse strains exhibit different susceptibilities to γ-ray-induced thymic lymphomas. Our previous study identified Mtf-1 (metal responsive transcription factor-1) as a candidate susceptibility gene, which is involved in the radiation-induced signaling pathway that regulates the cellular reactive oxygen species (ROS). To reveal the mechanism for the increased susceptibility conferred by Mtf-1 locus, we examined early effects of γ-ray on ROS levels in vivo and its difference between Mtf-1 susceptible and resistant congenic mice. Here, we show the detection of clonally growing thymocytes at 4 weeks after irradiation, indicating the start of clonal expansion at a very early stage. We also show that large thymocytes with higher ROS levels and a proliferation capacity were more numerous in the Mtf-1 susceptible mice than the resistant mice when examined at 7 days after irradiation, although such tendency was not found in mice lacking one allele of Bcl11b tumor suppressor gene. This high retention of the large thymocytes, at a high risk for ROS-induced mutation, is a compensatory proliferation and regeneration response to depletion of the thymocytes after irradiation and the response is likely to augment the development of prelymphoma cells leading to thymic lymphomas

Delay-based Passenger Car Equivalent at Signalized Intersections in Iran

Directory of Open Access Journals (Sweden)

Habibollah Nassiri

2017-04-01

Full Text Available Due to their different sizes and operational characteristics, vehicles other than passenger cars have a different influence on traffic operations especially at intersections. The passenger car equivalent (PCE is the parameter that shows how many passenger cars must be substituted for a specific heavy vehicle to represent its influence on traffic operation. PCE is commonly estimated using headway-based methods that consider the excess headway utilized by heavy vehicles. In this research, the PCE was estimated based on the delay parameter at three signalized intersections in Tehran, Iran. The data collected were traffic volume, travel time for each movement, signalization, and geometric design information. These data were analysed and three different models, one for each intersection, were constructed and calibrated using TRAF-NETSIM simulation software for unsaturated traffic conditions. PCE was estimated under different scenarios and the number of approach movements at each intersection. The results showed that for approaches with only one movement, PCE varies from 1.1 to 1.65. Similarly, for approaches with two and three movements, the PCE varies from 1.07 to 1.99 and from 0.76 to 3.6, respectively. In addition, a general model was developed for predicting PCE for intersections with all of the movements considered. The results obtained from this model showed that the average PCE of 1.5 is similar to the value recommended by the HCM (Highway Capacity Manual 1985. However, the predicted PCE value of 1.9 for saturated threshold is closer to the PCE value of 2 which was recommended by the HCM 2000 and HCM 2010.

Maximum likelihood window for time delay estimation

International Nuclear Information System (INIS)

Lee, Young Sup; Yoon, Dong Jin; Kim, Chi Yup

2004-01-01

Time delay estimation for the detection of leak location in underground pipelines is critically important. Because the exact leak location depends upon the precision of the time delay between sensor signals due to leak noise and the speed of elastic waves, the research on the estimation of time delay has been one of the key issues in leak lovating with the time arrival difference method. In this study, an optimal Maximum Likelihood window is considered to obtain a better estimation of the time delay. This method has been proved in experiments, which can provide much clearer and more precise peaks in cross-correlation functions of leak signals. The leak location error has been less than 1 % of the distance between sensors, for example the error was not greater than 3 m for 300 m long underground pipelines. Apart from the experiment, an intensive theoretical analysis in terms of signal processing has been described. The improved leak locating with the suggested method is due to the windowing effect in frequency domain, which offers a weighting in significant frequencies.

Towards Interactive, Incremental Programming of ROS Nodes

DEFF Research Database (Denmark)

Adam, Marian Sorin; Schultz, Ulrik Pagh

Writing software for controlling robots is a complex task, usually demanding command of many programming languages and requiring significant experimentation. We believe that a bottom-up development process that complements traditional component- and MDSD-based approaches can facilitate...... experimentation. We propose the use of an internal DSL providing both a tool to interactively create ROS nodes and a behaviour-replacement mechanism to interactively reshape existing ROS nodes by wrapping the external interfaces (the publish/subscribe topics), dynamically controlled using the Python command line...

MAP17, a ROS-dependent oncogene

International Nuclear Information System (INIS)

Carnero, Amancio

2012-01-01

MAP17 is a small 17 kDa non-glycosylated membrane protein previously identified as being overexpressed in carcinomas. Breast tumor cells that overexpress MAP17 show an increased tumoral phenotype with enhanced proliferative capabilities both in the presence or the absence of contact inhibition, decreased apoptotic sensitivity, and increased migration. MAP17-expressing clones also grow better in nude mice. The increased malignant cell behavior induced by MAP17 is associated with an increase in reactive oxygen species (ROS) production, and the treatment of MAP17-expressing cells with antioxidants results in a reduction in the tumorigenic properties of these cells. The MAP17-dependent increase in ROS and tumorigenesis relies on its PDZ-binding domain because disruption of this sequence by point mutations abolishes the ability of MAP17 to enhance ROS production and tumorigenesis. MAP17 is overexpressed in a great variety of human carcinomas, including breast tumors. Immunohistochemical analysis of MAP17 during cancer progression demonstrates that overexpression of the protein strongly correlates with tumoral progression. Generalized MAP17 overexpression in human carcinomas indicates that MAP17 can be a good marker for tumorigenesis and, especially, for malignant progression.

Time-delay analyzer with continuous discretization

International Nuclear Information System (INIS)

Bayatyan, G.L.; Darbinyan, K.T.; Mkrtchyan, K.K.; Stepanyan, S.S.

1988-01-01

A time-delay analyzer is described which when triggered by a start pulse of adjustable duration performs continuous discretization of the analyzed signal within nearly 22 ns time intervals, the recording in a memory unit with following slow read-out of the information to the computer and its processing. The time-delay analyzer consists of four CAMAC-VECTOR systems of unit width. With its help one can separate comparatively short, small-amplitude rare signals against the background of quasistationary noise processes. 4 refs.; 3 figs

Prolonged Exposure of Cortical Neurons to Oligomeric Amyloid-β Impairs NMDA Receptor Function Via NADPH Oxidase-Mediated ROS Production: Protective Effect of Green Tea (--Epigallocatechin-3-Gallate

Directory of Open Access Journals (Sweden)

Yan He

2011-01-01

Full Text Available Excessive production of Aβ (amyloid β-peptide has been shown to play an important role in the pathogenesis of AD (Alzheimer's disease. Although not yet well understood, aggregation of Aβ is known to cause toxicity to neurons. Our recent study demonstrated the ability for oligomeric Aβ to stimulate the production of ROS (reactive oxygen species in neurons through an NMDA (N-methyl-D-aspartate-dependent pathway. However, whether prolonged exposure of neurons to aggregated Aβ is associated with impairment of NMDA receptor function has not been extensively investigated. In the present study, we show that prolonged exposure of primary cortical neurons to Aβ oligomers caused mitochondrial dysfunction, an attenuation of NMDA receptor-mediated Ca2+ influx and inhibition of NMDA-induced AA (arachidonic acid release. Mitochondrial dysfunction and the decrease in NMDA receptor activity due to oligomeric Aβ are associated with an increase in ROS production. Gp91ds-tat, a specific peptide inhibitor of NADPH oxidase, and Mn(III-tetrakis(4-benzoic acid-porphyrin chloride, an ROS scavenger, effectively abrogated Aβ-induced ROS production. Furthermore, Aβ-induced mitochondrial dysfunction, impairment of NMDA Ca2+ influx and ROS production were prevented by pretreatment of neurons with EGCG [(–-epigallocatechin-3-gallate], a major polyphenolic component of green tea. Taken together, these results support a role for NADPH oxidase-mediated ROS production in the cytotoxic effects of Aβ, and demonstrate the therapeutic potential of EGCG and other dietary polyphenols in delaying onset or retarding the progression of AD.

MicroRNA-145 suppresses ROS-induced Ca{sup 2+} overload of cardiomyocytes by targeting CaMKIIδ

Energy Technology Data Exchange (ETDEWEB)

Cha, Min-Ji [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Jang, Jin-Kyung [College of Pharmacy, Sookmyung Women’s University, 52 HyoChangWon-Gil, Yongsan-ku, Seoul 140-742 (Korea, Republic of); Ham, Onju; Song, Byeong-Wook; Lee, Se-Yeon [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Lee, Chang Yeon; Park, Jun-Hee [Department of Integrated Omics for Biomedical Sciences, Graduate School, Yonsei University, 50 Yonsei-ro, Seodamun-gu, Seoul 120-759 (Korea, Republic of); Lee, Jiyun; Seo, Hyang-Hee [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Choi, Eunhyun [Severance Integrative Research Institute for Cerebral and Cardiovascular Disease, Yonsei University Health System, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Jeon, Woo-min [Department of Animal Resource, Sahmyook University, Seoul 139-742 (Korea, Republic of); Hwang, Hye Jin [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Shin, Hyun-Taek [College of Pharmacy, Sookmyung Women’s University, 52 HyoChangWon-Gil, Yongsan-ku, Seoul 140-742 (Korea, Republic of); and others

2013-06-14

Highlights: •CaMKIIδ mediates H{sub 2}O{sub 2}-induced Ca{sup 2+} overload in cardiomyocytes. •miR-145 can inhibit Ca{sup 2+} overload. •A luciferase assay confirms that miR-145 functions as a CaMKIIδ-targeting miRNA. •Overexpression of miR-145 regulates CaMKIIδ-related genes and ameliorates apoptosis. -- Abstract: A change in intracellular free calcium (Ca{sup 2+}) is a common signaling mechanism of reperfusion-induced cardiomyocyte death. Calcium/calmodulin dependent protein kinase II (CaMKII) is a critical regulator of Ca{sup 2+} signaling and mediates signaling pathways responsible for functions in the heart including hypertrophy, apoptosis, arrhythmia, and heart disease. MicroRNAs (miRNA) are involved in the regulation of cell response, including survival, proliferation, apoptosis, and development. However, the roles of miRNAs in Ca{sup 2+}-mediated apoptosis of cardiomyocytes are uncertain. Here, we determined the potential role of miRNA in the regulation of CaMKII dependent apoptosis and explored its underlying mechanism. To determine the potential roles of miRNAs in H{sub 2}O{sub 2}-mediated Ca{sup 2+} overload, we selected and tested 6 putative miRNAs that targeted CaMKIIδ, and showed that miR-145 represses CaMKIIδ protein expression and Ca{sup 2+} overload. We confirmed CaMKIIδ as a direct downstream target of miR-145. Furthermore, miR-145 regulates Ca{sup 2+}-related signals and ameliorates apoptosis. This study demonstrates that miR-145 regulates reactive oxygen species (ROS)-induced Ca{sup 2+} overload in cardiomyocytes. Thus, miR-145 affects ROS-mediated gene regulation and cellular injury responses.

Reactive Oxygen Species-Mediated Loss of Synaptic Akt1 Signaling Leads to Deficient Activity-Dependent Protein Translation Early in Alzheimer's Disease.

Science.gov (United States)

Ahmad, Faraz; Singh, Kunal; Das, Debajyoti; Gowaikar, Ruturaj; Shaw, Eisha; Ramachandran, Arathy; Rupanagudi, Khader Valli; Kommaddi, Reddy Peera; Bennett, David A; Ravindranath, Vijayalakshmi

2017-12-01

Synaptic deficits are known to underlie the cognitive dysfunction seen in Alzheimer's disease (AD). Generation of reactive oxygen species (ROS) by β-amyloid has also been implicated in AD pathogenesis. However, it is unclear whether ROS contributes to synaptic dysfunction seen in AD pathogenesis and, therefore, we examined whether altered redox signaling could contribute to synaptic deficits in AD. Activity dependent but not basal translation was impaired in synaptoneurosomes from 1-month old presymptomatic APP Swe /PS1ΔE9 (APP/PS1) mice, and this deficit was sustained till middle age (MA, 9-10 months). ROS generation leads to oxidative modification of Akt1 in the synapse and consequent reduction in Akt1-mechanistic target of rapamycin (mTOR) signaling, leading to deficiency in activity-dependent protein translation. Moreover, we found a similar loss of activity-dependent protein translation in synaptoneurosomes from postmortem AD brains. Loss of activity-dependent protein translation occurs presymptomatically early in the pathogenesis of AD. This is caused by ROS-mediated loss of pAkt1, leading to reduced synaptic Akt1-mTOR signaling and is rescued by overexpression of Akt1. ROS-mediated damage is restricted to the synaptosomes, indicating selectivity. We demonstrate that ROS-mediated oxidative modification of Akt1 contributes to synaptic dysfunction in AD, seen as loss of activity-dependent protein translation that is essential for synaptic plasticity and maintenance. Therapeutic strategies promoting Akt1-mTOR signaling at synapses may provide novel target(s) for disease-modifying therapy in AD. Antioxid. Redox Signal. 27, 1269-1280.

Cytosolic calcium mediates RIP1/RIP3 complex-dependent necroptosis through JNK activation and mitochondrial ROS production in human colon cancer cells.

Science.gov (United States)

Sun, Wen; Wu, Xiaxia; Gao, Hongwei; Yu, Jie; Zhao, Wenwen; Lu, Jin-Jian; Wang, Jinhua; Du, Guanhua; Chen, Xiuping

2017-07-01

Necroptosis is a form of programmed necrosis mediated by signaling complexes with receptor-interacting protein 1 (RIP1) and RIP3 kinases as the main mediators. However, the underlying execution pathways of this phenomenon have yet to be elucidated in detail. In this study, a RIP1/RIP3 complex was formed in 2-methoxy-6-acetyl-7-methyljuglone (MAM)-treated HCT116 and HT29 colon cancer cells. With this formation, mitochondrial reactive oxygen species (ROS) levels increased, mitochondrial depolarization occurred, and ATP concentrations decreased. This process was identified as necroptosis. This finding was confirmed by experiments showing that MAM-induced cell death was attenuated by the pharmacological or genetic blockage of necroptosis signaling, including RIP1 inhibitor necrostatin-1s (Nec-1s) and siRNA-mediated gene silencing of RIP1 and RIP3, but was unaffected by caspase inhibitor z-vad-fmk or necrosis inhibitor 2-(1H-Indol-3-yl)-3-pentylamino-maleimide (IM54). Transmission electron microscopy (TEM) analysis further revealed the ultrastructural features of MAM-induced necroptosis. MAM-induced RIP1/RIP3 complex triggered necroptosis through cytosolic calcium (Ca 2+ ) accumulation and sustained c-Jun N-terminal kinase (JNK) activation. Both calcium chelator BAPTA-AM and JNK inhibitor SP600125 could attenuate necroptotic features, including mitochondrial ROS elevation, mitochondrial depolarization, and ATP depletion. 2-thenoyltrifluoroacetone (TTFA), which is a mitochondrial complex II inhibitor, was found to effectively reverse both MAM induced mitochondrial ROS generation and cell death, indicating the complex II was the ROS-producing site. The essential role of mitochondrial ROS was confirmed by the protective effect of overexpression of manganese superoxide dismutase (MnSOD). MAM-induced necroptosis was independent of TNFα, p53, MLKL, and lysosomal membrane permeabilization. In summary, our study demonstrated that RIP1/RIP3 complex-triggered cytosolic calcium

Stress-triggered redox signalling: what's in pROSpect?

Science.gov (United States)

Foyer, Christine H; Noctor, Graham

2016-05-01

Reactive oxygen species (ROS) have a profound influence on almost every aspect of plant biology. Here, we emphasize the fundamental, intimate relationships between light-driven reductant formation, ROS, and oxidative stress, together with compartment-specific differences in redox buffering and the perspectives for their analysis. Calculations of approximate H2 O2 concentrations in the peroxisomes are provided, and based on the likely values in other locations such as chloroplasts, we conclude that much of the H2 O2 detected in conventional in vitro assays is likely to be extracellular. Within the context of scant information on ROS perception mechanisms, we consider current knowledge, including possible parallels with emerging information on oxygen sensing. Although ROS can sometimes be signals for cell death, we consider that an equally important role is to transmit information from metabolism to allow appropriate cellular responses to developmental and environmental changes. Our discussion speculates on novel sensing mechanisms by which this could happen and how ROS could be counted by the cell, possibly as a means of monitoring metabolic flux. Throughout, we place emphasis on the positive effects of ROS, predicting that in the coming decades they will increasingly be defined as hallmarks of viability within a changing and challenging environment. © 2015 John Wiley & Sons Ltd.

PAU/GNSS-R: Implementation, Performance and First Results of a Real-Time Delay-Doppler Map Reflectometer Using Global Navigation Satellite System Signals

Directory of Open Access Journals (Sweden)

Enric Valencia

2008-05-01

Full Text Available Signals from Global Navigation Satellite Systems (GNSS were originally conceived for position and speed determination, but they can be used as signals of opportunity as well. The reflection process over a given surface modifies the properties of the scattered signal, and therefore, by processing the reflected signal, relevant geophysical data regarding the surface under study (land, sea, ice… can be retrieved. In essence, a GNSS-R receiver is a multi-channel GNSS receiver that computes the received power from a given satellite at a number of different delay and Doppler bins of the incoming signal. The first approaches to build such a receiver consisted of sampling and storing the scattered signal for later post-processing. However, a real-time approach to the problem is desirable to obtain immediately useful geophysical variables and reduce the amount of data. The use of FPGA technology makes this possible, while at the same time the system can be easily reconfigured. The signal tracking and processing constraints made necessary to fully design several new blocks. The uniqueness of the implemented system described in this work is the capability to compute in real-time Delay-Doppler maps (DDMs either for four simultaneous satellites or just one, but with a larger number of bins. The first tests have been conducted from a cliff over the sea and demonstrate the successful performance of the instrument to compute DDMs in real-time from the measured reflected GNSS/R signals. The processing of these measurements shall yield quantitative relationships between the sea state (mainly driven by the surface wind and the swell and the overall DDM shape. The ultimate goal is to use the DDM shape to correct the sea state influence on the L-band brightness temperature to improve the retrieval of the sea surface salinity (SSS.

ROS and trehalose regulate sclerotial development in Rhizoctonia solani AG-1 IA.

Science.gov (United States)

Wang, Chenjiaozi; Pi, Lei; Jiang, Shaofeng; Yang, Mei; Shu, Canwei; Zhou, Erxun

2018-05-01

Rhizoctonia solani AG-1 IA is the causal agent of rice sheath blight (RSB) and causes severe economic losses in rice-growing regions around the world. The sclerotia play an important role in the disease cycle of RSB. In this study, we report the effects of reactive oxygen species (ROS) and trehalose on the sclerotial development of R. solani AG-1 IA. Correlation was found between the level of ROS in R. solani AG-1 IA and sclerotial development. Moreover, we have shown the change of ROS-related enzymatic activities and oxidative burst occurs at the sclerotial initial stage. Six genes related to the ROS scavenging system were quantified in different sclerotial development stages by using quantitative RT-PCR technique, thereby confirming differential gene expression. Fluorescence microscopy analysis of ROS content in mycelia revealed that ROS were predominantly produced at the hyphal branches during the sclerotial initial stage. Furthermore, exogenous trehalose had a significant inhibitory effect on the activities of ROS-related enzymes and oxidative burst and led to a reduction in sclerotial dry weight. Taken together, the findings suggest that ROS has a promoting effect on the development of sclerotia, whereas trehalose serves as an inhibiting factor to sclerotial development in R. solani AG-1 IA. Copyright © 2018 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Man/machine interface algorithm for advanced delayed-neutron signal characterization system

International Nuclear Information System (INIS)

Gross, K.C.

1985-01-01

The present failed-element rupture detector (FERD) at Experimental Breeder Reactor II (EBR-II) consists of a single bank of delayed-neutron (DN) detectors at a fixed transit time from the core. Plans are currently under way to upgrade the FERD in 1986 and provide advanced DN signal characterization capability that is embodied in an equivalent-recoil-area (ERA) meter. The new configuration will make available to the operator a wealth of quantitative diagnostic information related to the condition and dynamic evolution of a fuel breach. The diagnostic parameters will include a continuous reading of the ERA value for the breach; the transit time, T/sub tr/, for DN emitters traveling from the core to the FERD; and the isotopic holdup time, T/sub h/, for the source. To enhance the processing, interpretation, and display of these parameters to the reactor operator, a man/machine interface (MMI) algorithm has been developed to run in the background on EBR-II's data acquisition system (DAS). The purpose of this paper is to describe the features and implementation of this newly developed MMI algorithm

Algebraic entropy for differential-delay equations

OpenAIRE

Viallet, Claude M.

2014-01-01

We extend the definition of algebraic entropy to a class of differential-delay equations. The vanishing of the entropy, as a structural property of an equation, signals its integrability. We suggest a simple way to produce differential-delay equations with vanishing entropy from known integrable differential-difference equations.

Role of ROS in Aβ42 Mediated Activation of Cerebral Endothelial Cells

Directory of Open Access Journals (Sweden)

Andrey Tsoy

2014-12-01

elevation. However, total expression levels of P-selectin were not changed following exposure to Aβ42. Pre-treatment with NAC attenuated Aβ42 induced P-selectin localization, while NAC alone did not significantly affect P selectin localization. As a positive control, H2O2 also increased P-selectin expression on the cell surface, which peaked after 30 minutes of H2O2 treatment. Exposure of CECs with Aβ42 promoted actin polymerization, which peaked after 10 minutes of Aβ42 treatment, while no significant increase of F-actin intensity was observed when cells were pre-treated with NAC. H2O2 was able to mimic Aβ42 induced oxidative stress, causing increased actin polymerization with similar timing.Conclusions. The results of our study have indicated that Aβ42 induced accumulation of P-selectin on the surface of bEnd3 cells and promoted actin polymerization, and all these events were correlated with ROS generation. The rapid post-translational cell signaling response mediated by ROS may well represent an important physiological trigger of the microvascular inflammatory responses in AD and requires further investigations.

Analysis of degree of nonlinearity and stochastic nature of HRV signal during meditation using delay vector variance method.

Science.gov (United States)

Reddy, L Ram Gopal; Kuntamalla, Srinivas

2011-01-01

Heart rate variability analysis is fast gaining acceptance as a potential non-invasive means of autonomic nervous system assessment in research as well as clinical domains. In this study, a new nonlinear analysis method is used to detect the degree of nonlinearity and stochastic nature of heart rate variability signals during two forms of meditation (Chi and Kundalini). The data obtained from an online and widely used public database (i.e., MIT/BIH physionet database), is used in this study. The method used is the delay vector variance (DVV) method, which is a unified method for detecting the presence of determinism and nonlinearity in a time series and is based upon the examination of local predictability of a signal. From the results it is clear that there is a significant change in the nonlinearity and stochastic nature of the signal before and during the meditation (p value > 0.01). During Chi meditation there is a increase in stochastic nature and decrease in nonlinear nature of the signal. There is a significant decrease in the degree of nonlinearity and stochastic nature during Kundalini meditation.

Virtual unit delay for digital frequency adaptive T/4 delay phase-locked loop system

DEFF Research Database (Denmark)

Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

2016-01-01

/processor with a fixed sampling rate considering the cost and complexity, where the number of unit delays that have been adopted should be an integer. For instance, in conventional digital control systems, a single-phase T/4 Delay Phase-Locked Loop (PLL) system takes 50 unit delays (i.e., in a 50-Hz system...... Delay PLL system should be done in its implementation. This process will result in performance degradation in the digital control system, as the exactly required number of delays is not realized. Hence, in this paper, a Virtual Unit Delay (VUD) has been proposed to address such challenges to the digital......Digital micro-controllers/processors enable the cost-effective control of grid-connected power converter systems in terms of system monitoring, signal processing (e.g., grid synchronization), control (e.g., grid current and voltage control), etc. Normally, the control is implemented in a micro-controller...

Sensitivity to external signals and synchronization properties of a non-isochronous auto-oscillator with delayed feedback

Science.gov (United States)

Tiberkevich, Vasil S.; Khymyn, Roman S.; Tang, Hong X.; Slavin, Andrei N.

2014-01-01

For auto-oscillators of different nature (e.g. active cells in a human heart under the action of a pacemaker, neurons in brain, spin-torque nano-oscillators, micro and nano-mechanical oscillators, or generating Josephson junctions) a critically important property is their ability to synchronize with each other. The synchronization properties of an auto oscillator are directly related to its sensitivity to external signals. Here we demonstrate that a non-isochronous (having generation frequency dependent on the amplitude) auto-oscillator with delayed feedback can have an extremely high sensitivity to external signals and unusually large width of the phase-locking band near the boundary of the stable auto-oscillation regime. This property could be used for the development of synchronized arrays of non-isochronous auto-oscillators in physics and engineering, and, for instance, might bring a better fundamental understanding of ways to control a heart arrythmia in medicine.

PKA activity exacerbates hypoxia-induced ROS formation and hypoxic injury in PC-12 cells.

Science.gov (United States)

Gozal, Evelyne; Metz, Cynthia J; Dematteis, Maurice; Sachleben, Leroy R; Schurr, Avital; Rane, Madhavi J

2017-09-05

Hypoxia is a primary factor in many pathological conditions. Hypoxic cell death is commonly attributed to metabolic failure and oxidative injury. cAMP-dependent protein kinase A (PKA) is activated in hypoxia and regulates multiple enzymes of the mitochondrial electron transport chain, thus may be implicated in cellular energy depletion and hypoxia-induced cell death. Wild type (WT) PC-12 cells and PKA activity-deficient 123.7 PC-12 cells were exposed to 3, 6, 12 and 24h hypoxia (0.1% or 5% O 2 ). Hypoxia, at 24h 0.1% O 2 , induced cell death and increased reactive oxygen species (ROS) in WT PC-12 cells. Despite lower ATP levels in normoxic 123.7 cells than in WT cells, hypoxia only decreased ATP levels in WT cells. However, menadione-induced oxidative stress similarly affected both cell types. While mitochondrial COX IV expression remained consistently higher in 123.7 cells, hypoxia decreased COX IV expression in both cell types. N-acetyl cysteine antioxidant treatment blocked hypoxia-induced WT cell death without preventing ATP depletion. Transient PKA catα expression in 123.7 cells partially restored hypoxia-induced ROS but did not alter ATP levels or COX IV expression. We conclude that PKA signaling contributes to hypoxic injury, by regulating oxidative stress rather than by depleting ATP levels. Therapeutic strategies targeting PKA signaling may improve cellular adaptation and recovery in hypoxic pathologies. Copyright © 2017 Elsevier B.V. All rights reserved.

PO2 cycling reduces diaphragm fatigue by attenuating ROS formation.

Science.gov (United States)

Zuo, Li; Diaz, Philip T; Chien, Michael T; Roberts, William J; Kishek, Juliana; Best, Thomas M; Wagner, Peter D

2014-01-01

Prolonged muscle exposure to low PO2 conditions may cause oxidative stress resulting in severe muscular injuries. We hypothesize that PO2 cycling preconditioning, which involves brief cycles of diaphragmatic muscle exposure to a low oxygen level (40 Torr) followed by a high oxygen level (550 Torr), can reduce intracellular reactive oxygen species (ROS) as well as attenuate muscle fatigue in mouse diaphragm under low PO2. Accordingly, dihydrofluorescein (a fluorescent probe) was used to monitor muscular ROS production in real time with confocal microscopy during a lower PO2 condition. In the control group with no PO2 cycling, intracellular ROS formation did not appear during the first 15 min of the low PO2 period. However, after 20 min of low PO2, ROS levels increased significantly by ∼30% compared to baseline, and this increase continued until the end of the 30 min low PO2 condition. Conversely, muscles treated with PO2 cycling showed a complete absence of enhanced fluorescence emission throughout the entire low PO2 period. Furthermore, PO2 cycling-treated diaphragm exhibited increased fatigue resistance during prolonged low PO2 period compared to control. Thus, our data suggest that PO2 cycling mitigates diaphragm fatigue during prolonged low PO2. Although the exact mechanism for this protection remains to be elucidated, it is likely that through limiting excessive ROS levels, PO2 cycling initiates ROS-related antioxidant defenses.

PO2 cycling reduces diaphragm fatigue by attenuating ROS formation.

Directory of Open Access Journals (Sweden)

Li Zuo

Full Text Available Prolonged muscle exposure to low PO2 conditions may cause oxidative stress resulting in severe muscular injuries. We hypothesize that PO2 cycling preconditioning, which involves brief cycles of diaphragmatic muscle exposure to a low oxygen level (40 Torr followed by a high oxygen level (550 Torr, can reduce intracellular reactive oxygen species (ROS as well as attenuate muscle fatigue in mouse diaphragm under low PO2. Accordingly, dihydrofluorescein (a fluorescent probe was used to monitor muscular ROS production in real time with confocal microscopy during a lower PO2 condition. In the control group with no PO2 cycling, intracellular ROS formation did not appear during the first 15 min of the low PO2 period. However, after 20 min of low PO2, ROS levels increased significantly by ∼30% compared to baseline, and this increase continued until the end of the 30 min low PO2 condition. Conversely, muscles treated with PO2 cycling showed a complete absence of enhanced fluorescence emission throughout the entire low PO2 period. Furthermore, PO2 cycling-treated diaphragm exhibited increased fatigue resistance during prolonged low PO2 period compared to control. Thus, our data suggest that PO2 cycling mitigates diaphragm fatigue during prolonged low PO2. Although the exact mechanism for this protection remains to be elucidated, it is likely that through limiting excessive ROS levels, PO2 cycling initiates ROS-related antioxidant defenses.

METHODS AND MEANS OF MEASURING THE COORDINATES OF AIRCRAFTS BY TIME DELAY OF SIGNALS IN MULTIPOSITIONING RADIO RANGEFINDING AERONAVIGATION AND LANDING SYSTEMS

Directory of Open Access Journals (Sweden)

Ya. V. Kondrashov

2014-01-01

Full Text Available The principles of operation of radio range finding interrogation-reply system to provide navigational and landing operations of aircraft are considered. A precise method of measuring of time delays of signals for determining the location of aircraft with high accuracy is proposed.

Calpain activation by ROS mediates human ether-a-go-go-related gene protein degradation by intermittent hypoxia.

Science.gov (United States)

Wang, N; Kang, H S; Ahmmed, G; Khan, S A; Makarenko, V V; Prabhakar, N R; Nanduri, J

2016-03-01

Human ether-a-go-go-related gene (hERG) channels conduct delayed rectifier K(+) current. However, little information is available on physiological situations affecting hERG channel protein and function. In the present study we examined the effects of intermittent hypoxia (IH), which is a hallmark manifestation of sleep apnea, on hERG channel protein and function. Experiments were performed on SH-SY5Y neuroblastoma cells, which express hERG protein. Cells were exposed to IH consisting of alternating cycles of 30 s of hypoxia (1.5% O2) and 5 min of 20% O2. IH decreased hERG protein expression in a stimulus-dependent manner. A similar reduction in hERG protein was also seen in adrenal medullary chromaffin cells from IH-exposed neonatal rats. The decreased hERG protein was associated with attenuated hERG K(+) current. IH-evoked hERG protein degradation was not due to reduced transcription or increased proteosome/lysomal degradation. Rather it was mediated by calcium-activated calpain proteases. Both COOH- and NH2-terminal sequences of the hERG protein were the targets of calpain-dependent degradation. IH increased reactive oxygen species (ROS) levels, intracellular Ca(2+) concentration ([Ca(2+)]i), calpain enzyme activity, and hERG protein degradation, and all these effects were prevented by manganese-(111)-tetrakis-(1-methyl-4-pyridyl)-porphyrin pentachloride, a membrane-permeable ROS scavenger. These results demonstrate that activation of calpains by ROS-dependent elevation of [Ca(2+)]i mediates hERG protein degradation by IH. Copyright © 2016 the American Physiological Society.

Attosecond Delays in Molecular Photoionization.

Science.gov (United States)

Huppert, Martin; Jordan, Inga; Baykusheva, Denitsa; von Conta, Aaron; Wörner, Hans Jakob

2016-08-26

We report measurements of energy-dependent photoionization delays between the two outermost valence shells of N_{2}O and H_{2}O. The combination of single-shot signal referencing with the use of different metal foils to filter the attosecond pulse train enables us to extract delays from congested spectra. Remarkably large delays up to 160 as are observed in N_{2}O, whereas the delays in H_{2}O are all smaller than 50 as in the photon-energy range of 20-40 eV. These results are interpreted by developing a theory of molecular photoionization delays. The long delays measured in N_{2}O are shown to reflect the population of molecular shape resonances that trap the photoelectron for a duration of up to ∼110 as. The unstructured continua of H_{2}O result in much smaller delays at the same photon energies. Our experimental and theoretical methods make the study of molecular attosecond photoionization dynamics accessible.

Ethylene signalling is mediating the early cadmium-induced oxidative challenge in Arabidopsis thaliana.

Science.gov (United States)

Schellingen, Kerim; Van Der Straeten, Dominique; Remans, Tony; Vangronsveld, Jaco; Keunen, Els; Cuypers, Ann

2015-10-01

Cadmium (Cd) induces the generation of reactive oxygen species (ROS) and stimulates ethylene biosynthesis. The phytohormone ethylene is a regulator of many developmental and physiological plant processes as well as stress responses. Previous research indicated various links between ethylene signalling and oxidative stress. Our results support a correlation between the Cd-induced oxidative challenge and ethylene signalling in Arabidopsis thaliana leaves. The effects of 24 or 72 h exposure to 5 μM Cd on plant growth and several oxidative stress-related parameters were compared between wild-type (WT) and ethylene insensitive mutants (etr1-1, ein2-1, ein3-1). Cadmium-induced responses observed in WT plants were mainly affected in etr1-1 and ein2-1 mutants, of which the growth was less inhibited by Cd exposure as compared to WT and ein3-1 mutants. Both etr1-1 and ein2-1 showed a delayed response in the glutathione (GSH) metabolism, including GSH levels and transcript levels of GSH synthesising and recycling enzymes. Furthermore, the expression of different oxidative stress marker genes was significantly lower in Cd-exposed ein2-1 mutants, evidencing that ethylene signalling is involved in early responses to Cd stress. A model for the cross-talk between ethylene signalling and oxidative stress is proposed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Redox signaling in cardiovascular pathophysiology: A focus on hydrogen peroxide and vascular smooth muscle cells

Directory of Open Access Journals (Sweden)

Chang Hyun Byon

2016-10-01

Full Text Available Oxidative stress represents excessive intracellular levels of reactive oxygen species (ROS, which plays a major role in the pathogenesis of cardiovascular disease. Besides having a critical impact on the development and progression of vascular pathologies including atherosclerosis and diabetic vasculopathy, oxidative stress also regulates physiological signaling processes. As a cell permeable ROS generated by cellular metabolism involved in intracellular signaling, hydrogen peroxide (H2O2 exerts tremendous impact on cardiovascular pathophysiology. Under pathological conditions, increased oxidase activities and/or impaired antioxidant systems results in uncontrolled production of ROS. In a pro-oxidant environment, vascular smooth muscle cells (VSMC undergo phenotypic changes which can lead to the development of vascular dysfunction such as vascular inflammation and calcification. Investigations are ongoing to elucidate the mechanisms for cardiovascular disorders induced by oxidative stress. This review mainly focuses on the role of H2O2 in regulating physiological and pathological signals in VSMC.

Calibration of Galileo signals for time metrology.

Science.gov (United States)

Defraigne, Pascale; Aerts, Wim; Cerretto, Giancarlo; Cantoni, Elena; Sleewaegen, Jean-Marie

2014-12-01

Using global navigation satellite system (GNSS) signals for accurate timing and time transfer requires the knowledge of all electric delays of the signals inside the receiving system. GNSS stations dedicated to timing or time transfer are classically calibrated only for Global Positioning System (GPS) signals. This paper proposes a procedure to determine the hardware delays of a GNSS receiving station for Galileo signals, once the delays of the GPS signals are known. This approach makes use of the broadcast satellite inter-signal biases, and is based on the ionospheric delay measured from dual-frequency combinations of GPS and Galileo signals. The uncertainty on the so-determined hardware delays is estimated to 3.7 ns for each isolated code in the L5 frequency band, and 4.2 ns for the ionosphere-free combination of E1 with a code of the L5 frequency band. For the calibration of a time transfer link between two stations, another approach can be used, based on the difference between the common-view time transfer results obtained with calibrated GPS data and with uncalibrated Galileo data. It is shown that the results obtained with this approach or with the ionospheric method are equivalent.

Amyloid β induces NLRP3 inflammasome activation in retinal pigment epithelial cells via NADPH oxidase- and mitochondria-dependent ROS production.

Science.gov (United States)

Wang, Ke; Yao, Yong; Zhu, Xue; Zhang, Kai; Zhou, Fanfan; Zhu, Ling

2017-06-01

Amyloid β (Aβ)-induced chronic inflammation is believed to be a key pathogenic process in early-stage age-related macular degeneration (AMD). Nucleotide oligomerization domain (NOD)-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation triggered by Aβ is responsible for retinal pigment epithelium (RPE) dysfunction in the onset of AMD; however, the detailed molecular mechanism remains unclear. In this study, we investigated the involvement of NADPH oxidase- and mitochondria-derived reactive oxygen species (ROS) in the process of Aβ 1-40 -induced NLRP3 inflammasome activation in LPS-primed ARPE-19 cells. The results showed that Aβ 1-40 could induce excessive ROS generation, MAPK/NF-κB signaling activation and subsequently NLRP3 inflammasome activation in LPS-primed ARPE-19 cells. Furthermore, the inductive effect of Aβ 1-40 on NLRP3 inflammasome activation was mediated in a manner dependent on NADPH oxidase- and mitochondria-derived ROS. Our findings may provide a novel insight into the molecular mechanism by which Aβ contributes to the early-stage AMD. © 2016 Wiley Periodicals, Inc.

Resveratrol prevents high glucose-induced epithelial-mesenchymal transition in renal tubular epithelial cells by inhibiting NADPH oxidase/ROS/ERK pathway.

Science.gov (United States)

He, Ting; Guan, Xu; Wang, Song; Xiao, Tangli; Yang, Ke; Xu, Xinli; Wang, Junping; Zhao, Jinghong

2015-02-15

Resveratrol (RSV) is reported to have renoprotective activity against diabetic nephropathy, while the mechanisms underlying its function have not been fully elucidated. In this study, we investigate the effect and related mechanism of RSV against high glucose-induced epithelial to mesenchymal transition (EMT) in human tubular epithelial cells (HK-2). A typical EMT is induced by high glucose in HK-2 cells, accompanied by increased levels of reactive oxygen species (ROS). RSV exhibits a strong ability to inhibit high glucose-induced EMT by decreasing intracellular ROS levels via down-regulation of NADPH oxidase subunits NOX1 and NOX4. The activation of extracellular signal-regulated kinase (ERK1/2) is found to be involved in high glucose-induced EMT in HK-2 cells. RSV, like NADPH oxidase inhibitor diphenyleneiodonium, can block ERK1/2 activation induced by high glucose. Our results demonstrate that RSV is a potent agent against high glucose-induced EMT in renal tubular cells via inhibition of NADPH oxidase/ROS/ERK1/2 pathway. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Magnetic pulse sharpener and delay-line

International Nuclear Information System (INIS)

Li Jin; Dai Guangsen; Xia Liansheng

2002-01-01

This paper describes a method to achieve short rise time pulse which has been delayed with a delay-line and magnetic pulse sharpener. A delay-line and two shock-lines are designed to carry pulsed signal with a maximum voltage magnitude up to 80 kV. A pulse of High voltage with arise time of 48 ns at a level of 0.1%-0.9% were achieved, and the attenuation in the line is very small

On the time delay of the ultrahigh-energy radiation signal from the source Cygnus X-3

International Nuclear Information System (INIS)

Arbuzov, B.A.; Razuvaev, E.A.

1986-01-01

The time delay of the signal from the source Gygnus X-3 detected by EAS observation with E ≥ 3x10 14 eV and counted off the maximum of radioburst in October, 1985 is considered. The effect is shown to get the explanation in the framework of the earlier proposed interpretation of the ulrahigh-energy radiation as free gluons. The agreement of this interpretation with the totality of experimental data is emphasized. A possibility of relict gluons to give a significant contribution to the density of a hidden mass in the Universe is discussed

ROS-mediated abiotic stress-induced programmed cell death in plants

Directory of Open Access Journals (Sweden)

Veselin ePetrov

2015-02-01

Full Text Available During the course of their ontogenesis, plants are continuously exposed to a large variety of abiotic stress factors which can damage tissues and jeopardize the survival of the organism unless properly countered. While animals can simply escape and thus evade stressors, plants as sessile organisms have developed complex strategies to withstand them. When the intensity of a detrimental factor is high, one of the defense programs employed by plants is the induction of programmed cell death (PCD. This is an active, genetically controlled process which is initiated to isolate and remove damaged tissues thereby ensuring the survival of the organism. The mechanism of PCD induction usually includes an increase in the levels of reactive oxygen species (ROS which are utilized as mediators of the stress signal. Abiotic stress-induced PCD is not only a process of fundamental biological importance, but also of considerable interest to agricultural practice as it has the potential to significantly influence crop yield. Therefore, numerous scientific enterprises have focused on elucidating the mechanisms leading to and controlling PCD in response to adverse conditions in plants. This knowledge may help to develop novel strategies to obtain more resilient crop varieties with improved tolerance and enhanced productivity. The aim of the present review is to summarize the recent advances in research on ROS-induced PCD related to abiotic stress and the role of the organelles in the process.

Salt-induced stabilization of EIN3/EIL1 confers salinity tolerance by deterring ROS accumulation in Arabidopsis.

Directory of Open Access Journals (Sweden)

Jinying Peng

2014-10-01

Full Text Available Ethylene has been regarded as a stress hormone to regulate myriad stress responses. Salinity stress is one of the most serious abiotic stresses limiting plant growth and development. But how ethylene signaling is involved in plant response to salt stress is poorly understood. Here we showed that Arabidopsis plants pretreated with ethylene exhibited enhanced tolerance to salt stress. Gain- and loss-of-function studies demonstrated that EIN3 (ETHYLENE INSENSITIVE 3 and EIL1 (EIN3-LIKE 1, two ethylene-activated transcription factors, are necessary and sufficient for the enhanced salt tolerance. High salinity induced the accumulation of EIN3/EIL1 proteins by promoting the proteasomal degradation of two EIN3/EIL1-targeting F-box proteins, EBF1 and EBF2, in an EIN2-independent manner. Whole-genome transcriptome analysis identified a list of SIED (Salt-Induced and EIN3/EIL1-Dependent genes that participate in salt stress responses, including several genes encoding reactive oxygen species (ROS scavengers. We performed a genetic screen for ein3 eil1-like salt-hypersensitive mutants and identified 5 EIN3 direct target genes including a previously unknown gene, SIED1 (At5g22270, which encodes a 93-amino acid polypeptide involved in ROS dismissal. We also found that activation of EIN3 increased peroxidase (POD activity through the direct transcriptional regulation of PODs expression. Accordingly, ethylene pretreatment or EIN3 activation was able to preclude excess ROS accumulation and increased tolerance to salt stress. Taken together, our study provides new insights into the molecular action of ethylene signaling to enhance plant salt tolerance, and elucidates the transcriptional network of EIN3 in salt stress response.

TNF-α mediates choroidal neovascularization by upregulating VEGF expression in RPE through ROS-dependent β-catenin activation.

Science.gov (United States)

Wang, Haibo; Han, Xiaokun; Wittchen, Erika S; Hartnett, M Elizabeth

2016-01-01

Inflammation, oxidative stress, and angiogenesis have been proposed to interact in age-related macular degeneration. It has been postulated that external stimuli that cause oxidative stress can increase production of vascular endothelial growth factor (VEGF) in retinal pigment epithelial (RPE) cells. In this study, we tested the hypothesis that the inflammatory cytokine, tumor necrosis factor alpha (TNF-α), contributed to choroidal neovascularization (CNV) by upregulating VEGF in RPE through intracellular reactive oxygen species (ROS)-dependent signaling and sought to understand the mechanisms involved. In a murine laser-induced CNV model, 7 days after laser treatment and intravitreal neutralizing mouse TNF-α antibody or isotype immunoglobulin G (IgG) control, the following measurements were made: 1) TNF-α protein and VEGF protein in RPE/choroids with western blot, 2) CNV volume in RPE/choroidal flatmounts, and 3) semiquantification of oxidized phospholipids stained with E06 antibody within CNV with immunohistochemistry (IHC). In cultured human RPE cells treated with TNF-α or PBS control, 1) ROS generation was measured using the 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence assay, and 2) NOX4 protein and VEGF protein or mRNA were measured with western blot or quantitative real-time PCR in cells pretreated with apocynin or nicotinamide adenine dinucleotide phosphate-oxidase (NADPH) inhibitor, VAS 2870, or transfected with p22phox siRNA, and each was compared to its appropriate control. Western blots of phosphorylated p65 (p-p65), total p65 and β-actin, and quantitative real-time PCR of VEGF mRNA were measured in human RPE cells treated with TNF-α and pretreatment with the nuclear factor kappa B inhibitor, Bay 11-7082 or control. Western blots of β-catenin, VEGF, and p22phox and coimmunoprecipitation of β-catenin and T-cell transcriptional factor were performed in human RPE cells treated with TNF-α following pretreatment with �

Nanomedicine in the ROS-mediated pathophysiology: Applications and clinical advances.

Science.gov (United States)

Nash, Kevin M; Ahmed, Salahuddin

2015-11-01

Reactive oxygen species (ROS) are important in regulating normal cell physiological functions, but when produced in excess lead to the augmented pathogenesis of various diseases. Among these, ischemia reperfusion injury, Alzheimer's disease and rheumatoid arthritis are particularly important. Since ROS can be counteracted by a variety of antioxidants, natural and synthetic antioxidants have been developed. However, due to the ubiquitous production of ROS in living systems, poor in vivo efficiency of these agents and lack of target specificity, the current clinical modalities to treat oxidative stress damage are limited. Advances in the developing field of nanomedicine have yielded nanoparticles that can prolong antioxidant activity, and target specificity of these agents. This article reviews recent advances in antioxidant nanoparticles and their applications to manage oxidative stress-mediated diseases. Production of reactive oxygen species (ROS) is a purely physiological process in many disease conditions. However, excessive and uncontrolled production will lead to oxidative stress and further tissue damage. Advances in nanomedicine have provided many novel strategies to try to combat and counteract ROS. In this review article, the authors comprehensively highlighted the current status and future developments in using nanotechnology for providing novel therapeutic options in this field. Copyright © 2015 Elsevier Inc. All rights reserved.

Social sustainability and urban renewal on the example of Inner-Erzsébetváros in Budapest

OpenAIRE

Gábor Csanádi; Adrienne Csizmady; Gergely Olt

2011-01-01

This article outlines recent social processes in central Budapest — Inner-Erzsébetváros, focusing on social sustainability and gentrification, and presents the potential social conflicts emerging in this area. We examine the recent history and trends and possible long-term effects of real-estate development in the research area. The article concludes that the gentrification events in central Budapest could be a warning signal of future social displacement and social exclusion.

Dense solar wind cloud geometries deduced from comparisons of radio signal delay and in situ plasma measurements

Science.gov (United States)

Landt, J. A.

1974-01-01

The geometries of dense solar wind clouds are estimated by comparing single-location measurements of the solar wind plasma with the average of the electron density obtained by radio signal delay measurements along a radio path between earth and interplanetary spacecraft. Several of these geometries agree with the current theoretical spatial models of flare-induced shock waves. A new class of spatially limited structures that contain regions with densities greater than any observed in the broad clouds is identified. The extent of a cloud was found to be approximately inversely proportional to its density.

ROS1 Expression in Invasive Ductal Carcinoma of the Breast Related to Proliferation Activity

OpenAIRE

Eom, Minseob; Lkhagvadorj, Sayamaa; Oh, Sung Soo; Han, Airi; Park, Kwang Hwa

2013-01-01

Purpose ROS1 is an oncogene, expressed primarily in glioblastomas of the brain that has been hypothesized to mediate the effects of early stage tumor progression. In addition, it was reported that ROS1 expression was observed in diverse cancer tissue or cell lines and ROS1 is associated with the development of several tumors. However, ROS1 expression has not been studied in breast cancer to date. Therefore, we investigated ROS1 expression at the protein and gene level to compare expression pa...

Identification and characterisation of ROS modulator 1 in Lampetra japonica.

Science.gov (United States)

Zhao, Chunhui; Feng, Bin; Cao, Ying; Xie, Peng; Xu, Jie; Pang, Yue; Liu, Xin; Li, Qingwei

2013-08-01

Reactive oxygen species (ROS) are a heterogeneous group of highly reactive molecules that oxidise targets in biological systems. ROS are also considered important immune regulators. In this study, we identified a homologue of reactive oxygen species modulator 1 (Romo1) in the Japanese lamprey (Lampetra japonica). The L japonica Romo1 (Lj-Romo1) gene shares high sequence homology with the Romo1 genes of jawed vertebrates. Real-time quantitative PCR demonstrated the wide distribution of Lj-Romo1 in lamprey tissues. Furthermore, after the lampreys were stimulated with lipopolysaccharide (LPS), the level of Lj-Romo1 mRNA was markedly up-regulated in the liver, gill, kidney, and intestine tissues. Lj-Romo1 was localised to the mitochondria and has the capacity to increase the ROS level in cells. The results obtained in the present study will help us to understand the roles of Romo1 in ROS production and innate immune responses in jawless vertebrates. Copyright © 2013 Elsevier Ltd. All rights reserved.

Upregulated ROS production induced by the proteasome inhibitor MG-132 on XBP1 gene expression and cell apoptosis in Tca-8113 cells.

Science.gov (United States)

Chen, Hai-ying; Ren, Xiao-yan; Wang, Wei-hua; Zhang, Ying-xin; Chen, Shuang-feng; Zhang, Bin; Wang, Le-xin

2014-07-01

Exposure of Tca-8113 cells to proteasome inhibitor carbobenzoxy-Leu-Leu-leucinal (MG-132) causing apoptosis is associated with endoplasmic reticulum (ER) stress. X-box-binding protein-1 (XBP1) is an important regulator of a subset of genes active during ER stress, which is related to cell survival and is required for tumor growth. The present study is to evaluate the effect of MG-132 on ROS production, XBP1 gene expression, tumor necrosis factor receptor-associated factor 2 (TRAF2), ASK1 and c-jun protein expression in tongue squamous cell carcinoma cell line Tca-8113 cells. ROS production was measured by reactive oxygen species assay. X-box binding protein-1 (XBP1) mRNA was analyzed by real-time-PCR, TRAF2, ASK1 and c-jun protein were investigated by western blot and immunocytochemistry respectively. The result indicated that ROS production, TRAF2, ASK1 and c-jun were elevated in MG-132 treated cells. Giving ROS scavenger N-acetyl-L-cysteine (NAC) largely prevented the effects of MG-132. Furthermore, treating with MG-132 lead to decreased XBP1 mRNA expression but could not completely block the expression of XBP1. Taken together, these findings provide the evidence that MG-132 induced ER stress lead to Tca-8113 cells apoptosis through ROS generation and TRAF2-ASK1-JNK signal pathway activation. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Lysosome-controlled efficient ROS overproduction against cancer cells with a high pH-responsive catalytic nanosystem

Science.gov (United States)

Fu, Jingke; Shao, Yiran; Wang, Liyao; Zhu, Yingchun

2015-04-01

Excess reactive oxygen species (ROS) have been proved to damage cancer cells efficiently. ROS overproduction is thus greatly desirable for cancer therapy. To date, ROS production is generally uncontrollable and outside cells, which always bring severe side-effects in the vasculature. Since most ROS share a very short half-life and primarily react close to their site of formation, it would be more efficient if excess ROS are controllably produced inside cancer cells. Herein, we report an efficient lysosome-controlled ROS overproduction via a pH-responsive catalytic nanosystem (FeOx-MSNs), which catalyze the decomposition of H2O2 to produce considerable ROS selectively inside the acidic lysosomes (pH 5.0) of cancer cells. After a further incorporation of ROS-sensitive TMB into the nanosystem (FeOx-MSNs-TMB), both a distinct cell labeling and an efficient death of breast carcinoma cells are obtained. This lysosome-controlled efficient ROS overproduction suggests promising applications in cancer treatments.Excess reactive oxygen species (ROS) have been proved to damage cancer cells efficiently. ROS overproduction is thus greatly desirable for cancer therapy. To date, ROS production is generally uncontrollable and outside cells, which always bring severe side-effects in the vasculature. Since most ROS share a very short half-life and primarily react close to their site of formation, it would be more efficient if excess ROS are controllably produced inside cancer cells. Herein, we report an efficient lysosome-controlled ROS overproduction via a pH-responsive catalytic nanosystem (FeOx-MSNs), which catalyze the decomposition of H2O2 to produce considerable ROS selectively inside the acidic lysosomes (pH 5.0) of cancer cells. After a further incorporation of ROS-sensitive TMB into the nanosystem (FeOx-MSNs-TMB), both a distinct cell labeling and an efficient death of breast carcinoma cells are obtained. This lysosome-controlled efficient ROS overproduction suggests

Tyrosine kinase receptor c-ros-oncogene 1 inhibition alleviates aberrant bone formation of TWIST-1 haploinsufficient calvarial cells from Saethre-Chotzen syndrome patients.

Science.gov (United States)

Camp, Esther; Anderson, Peter J; Zannettino, Andrew C W; Glackin, Carlotta A; Gronthos, Stan

2018-09-01

Saethre-Chotzen syndrome (SCS), associated with TWIST-1 mutations, is characterized by premature fusion of cranial sutures. TWIST-1 haploinsufficiency, leads to alterations in suture mesenchyme cellular gene expression patterns, resulting in aberrant osteogenesis and craniosynostosis. We analyzed the expression of the TWIST-1 target, Tyrosine kinase receptor c-ros-oncogene 1 (C-ROS-1) in TWIST-1 haploinsufficient calvarial cells derived from SCS patients and calvaria of Twist-1 del/+ mutant mice and found it to be highly expressed when compared to TWIST-1 wild-type controls. Knock-down of C-ROS-1 expression in TWIST-1 haploinsufficient calvarial cells derived from SCS patients was associated with decreased capacity for osteogenic differentiation in vitro. Furthermore, treatment of human SCS calvarial cells with the tyrosine kinase chemical inhibitor, Crizotinib, resulted in reduced C-ROS-1 activity and the osteogenic potential of human SCS calvarial cells with minor effects on cell viability or proliferation. Cultured human SCS calvarial cells treated with Crizotinib exhibited a dose-dependent decrease in alkaline phosphatase activity and mineral deposition, with an associated decrease in expression levels of Runt-related transcription factor 2 and OSTEOPONTIN, with reduced PI3K/Akt signalling in vitro. Furthermore, Crizotinib treatment resulted in reduced BMP-2 mediated bone formation potential of whole Twist-1 del/+ mutant mouse calvaria organotypic cultures. Collectively, these results suggest that C-ROS-1 promotes osteogenic differentiation of TWIST-1 haploinsufficient calvarial osteogenic progenitor cells. Furthermore, the aberrant osteogenic potential of these cells is inhibited by the reduction of C-ROS-1. Therefore, targeting C-ROS-1 with a pharmacological agent, such as Crizotinib, may serve as a novel therapeutic strategy to alleviate craniosynostosis associated with aberrant TWIST-1 function. © 2018 Wiley Periodicals, Inc.

Carnosol induces ROS-mediated beclin1-independent autophagy and apoptosis in triple negative breast cancer.

Directory of Open Access Journals (Sweden)

Yusra Al Dhaheri

Full Text Available In this study we investigated the in vitro and in vivo anticancer effect of carnosol, a naturally occurring polyphenol, in triple negative breast cancer.We found that carnosol significantly inhibited the viability and colony growth induced G2 arrest in the triple negative MDA-MB-231. Blockade of the cell cycle was associated with increased p21/WAF1 expression and downregulation of p27. Interestingly, carnosol was found to induce beclin1-independent autophagy and apoptosis in MDA-MB-231 cells. The coexistence of both events, autophagy and apoptosis, was confirmed by electron micrography. Induction of autophagy was found to be an early event, detected within 3 h post-treatment, which subsequently led to apoptosis. Carnosol treatment also caused a dose-dependent increase in the levels of phosphorylated extracellular signal-regulated kinase 1 and 2 (pERK1/2. Moreover, we show that carnosol induced DNA damage, reduced the mitochondrial potential and triggered the activation of the intrinsic and extrinsic apoptotic pathway. Furthermore, we found that carnosol induced a dose-dependent generation of reactive oxygen species (ROS and inhibition of ROS by tiron, a ROS scavenger, blocked the induction of autophagy and apoptosis and attenuated DNA damage. To our knowledge, this is the first report to identify the induction of autophagy by carnosol.In conclusion our findings provide strong evidence that carnosol may be an alternative therapeutic candidate against the aggressive form of breast cancer and hence deserves more exploration.

Rosácea fulminante: relato de caso

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José Otávio Alquezar Gozzano

2016-10-01

Full Text Available Introdução: Rosácea fulminante (RF ou pioderma facial é uma doença rara, descrita em 1940 por Kierland e O’Leary. É considerada uma variante extrema de rosácea conglobata, esta, consiste em formação de placas e abscessos hemorrágicos na pele. A RF tem sua etiologia desconhecida, porém há teorias que relacionam seu acometimento com a variação de hormônios femininos e a ingestão de vitamina B12. A RF é frequente em mulheres, principalmente pós- adolescentes. Apresenta-se abruptamente na face, amiúde na região mento- mandibular, através de pápulas inflamatórias, pústulas, cistos e nódulos com comedões escassos ou inexistentes, além de abcessos, sem manifestações sistêmicas e com a recidiva rara. Seu diagnóstico é fundamentalmente clínico, apenas com a história do paciente, sem necessidade de exames complementares. Para o tratamento, são utilizados corticoides orais, isotretinoína oral e antibióticos a fim de minimizar as sequelas físicas e psicológicas. Objetivo: Relatar caso de paciente com diagnóstico de rosácea fulminante. Metodologia: Paciente diagnosticada com rosácea fulminante atendida em serviço ambulatorial e revisão de literatura. Relato de caso: Paciente do sexo feminino, 19 anos, refere lesões súbitas em face há uma semana. Nega quadro acneico anterior, histórias de alergias e outras comorbidades. Relata ausência de uso de anticoncepcionais orais há 5 meses e data de última menstruação há 3 semanas, sem atraso menstrual. Ao exame: pápulas eritematosas e pústulas, além de pequenos nódulos inflamatórios na face. Hipótese diagnóstica: RF. Como conduta, foi prescrito tetraciclina. Conclusões: A RF é uma forma infrequente de rosácea, sendo importante o diagnóstico precoce e tratamento eficaz, a fim de melhorar a qualidade de vida do paciente.

Nitric Oxide: A Multitasked Signaling Gas in Plants

KAUST Repository

Domingos, Patricia

2014-12-01

Nitric oxide (NO) is a gaseous reactive oxygen species (ROS) that has evolved as a signaling hormone in many physiological processes in animals. In plants it has been demonstrated to be a crucial regulator of development, acting as a signaling molecule present at each step of the plant life cycle. NO has also been implicated as a signal in biotic and abiotic responses of plants to the environment. Remarkably, despite this plethora of effects and functional relationships, the fundamental knowledge of NO production, sensing, and transduction in plants remains largely unknown or inadequately characterized. In this review we cover the current understanding of NO production, perception, and action in different physiological scenarios. We especially address the issues of enzymatic and chemical generation of NO in plants, NO sensing and downstream signaling, namely the putative cGMP and Ca2+ pathways, ion-channel activity modulation, gene expression regulation, and the interface with other ROS, which can have a profound effect on both NO accumulation and function. We also focus on the importance of NO in cell–cell communication during developmental processes and sexual reproduction, namely in pollen tube guidance and embryo sac fertilization, pathogen defense, and responses to abiotic stress.

N-n-butyl haloperidol iodide ameliorates hypoxia/reoxygenation injury through modulating the LKB1/AMPK/ROS pathway in cardiac microvascular endothelial cells.

Science.gov (United States)

Lu, Binger; Wang, Bin; Zhong, Shuping; Zhang, Yanmei; Gao, Fenfei; Chen, Yicun; Zheng, Fuchun; Shi, Ganggang

2016-06-07

Endothelial cells are highly sensitive to hypoxia and contribute to myocardial ischemia/reperfusion injury. We have reported that N-n-butyl haloperidol iodide (F2) can attenuate hypoxia/reoxygenation (H/R) injury in cardiac microvascular endothelial cells (CMECs). However, the molecular mechanisms remain unclear. Neonatal rat CMECs were isolated and subjected to H/R. Pretreatment of F2 leads to a reduction in H/R injury, as evidenced by increased cell viability, decreased lactate dehydrogenase (LDH) leakage and apoptosis, together with enhanced AMP-activated protein kinase (AMPK) and liver kinase B1 (LKB1) phosphorylation in H/R ECs. Blockade of AMPK with compound C reversed F2-induced inhibition of H/R injury, as evidenced by decreased cell viability, increased LDH release and apoptosis. Moreover, compound C also blocked the ability of F2 to reduce H/R-induced reactive oxygen species (ROS) generation. Supplementation with the ROS scavenger N-acetyl-L-cysteine (NAC) reduced ROS levels, increased cell survival rate, and decreased both LDH release and apoptosis after H/R. In conclusion, our data indicate that F2 may mitigate H/R injury by stimulating LKB1/AMPK signaling pathway and subsequent suppression of ROS production in CMECs.

TECHNICAL DESIGN NOTE: Picosecond resolution programmable delay line

Science.gov (United States)

Suchenek, Mariusz

2009-11-01

The note presents implementation of a programmable delay line for digital signals. The tested circuit has a subnanosecond delay range programmable with a resolution of picoseconds. Implementation of the circuit was based on low-cost components, easily available on the market.

CysLT1 receptor-induced human airway smooth muscle cells proliferation requires ROS generation, EGF receptor transactivation and ERK1/2 phosphorylation

Directory of Open Access Journals (Sweden)

Capra Valérie

2006-03-01

Full Text Available Abstract Background Cysteine-containing leukotrienes (cysteinyl-LTs are pivotal inflammatory mediators that play important roles in the pathophysiology of asthma, allergic rhinitis, and other inflammatory conditions. In particular, cysteinyl-LTs exert a variety of effects with relevance to the aetiology of asthma such as smooth muscle contraction, eosinophil recruitment, increased microvascular permeability, enhanced mucus secretion and decreased mucus transport and, finally, airway smooth muscle cells (ASMC proliferation. We used human ASMC (HASMC to identify the signal transduction pathway(s of the leukotriene D4 (LTD4-induced DNA synthesis. Methods Proliferation of primary HASMC was measured by [3H]thymidine incorporation. Phosphorylation of EGF receptor (EGF-R and ERK1/2 was assessed with a polyclonal anti-EGF-R or anti-phosphoERKl/2 monoclonal antibody. A Ras pull-down assay kit was used to evaluate Ras activation. The production of reactive oxygen species (ROS was estimated by measuring dichlorodihydrofluorescein (DCF oxidation. Results We demonstrate that in HASMC LTD4-stimulated thymidine incorporation and potentiation of EGF-induced mitogenic signaling mostly depends upon EGF-R transactivation through the stimulation of CysLT1-R. Accordingly, we found that LTD4 stimulation was able to trigger the increase of Ras-GTP and, in turn, to activate ERK1/2. We show here that EGF-R transactivation was sensitive to pertussis toxin (PTX and phosphoinositide 3-kinase (PI3K inhibitors and that it occurred independently from Src activity, despite the observation of a strong impairment of LTD4-induced DNA synthesis following Src inhibition. More interestingly, CysLT1-R stimulation increased the production of ROS and N-acetylcysteine (NAC abolished LTD4-induced EGF-R phosphorylation and thymidine incorporation. Conclusion Collectively, our data demonstrate that in HASMC LTD4 stimulation of a Gi/o coupled CysLT1-R triggers the transactivation of the EGF

Modulation of ROS levels in fibroblasts by altering mitochondria regulates the process of wound healing.

Science.gov (United States)

Janda, Jaroslav; Nfonsam, Valentine; Calienes, Fernanda; Sligh, James E; Jandova, Jana

2016-05-01

Mitochondria are the major source of reactive oxygen species (ROS) in fibroblasts which are thought to be crucial regulators of wound healing with a potential to affect the expression of nuclear genes involved in this process. ROS generated by mitochondria are involved in all stages of tissue repair process but the regulation of ROS-generating system in fibroblasts still remains poorly understood. The purpose of this study was to better understand molecular mechanisms of how the regulation of ROS levels generated by mitochondria may influence the process of wound repair. Cybrid model system of mtDNA variations was used to study the functional consequences of altered ROS levels on wound healing responses in a uniform nuclear background of cultured ρ(0) fibroblasts. Mitochondrial ROS in cybrids were modulated by antioxidants that quench ROS to examine their ability to close the wound. Real-time PCR arrays were used to investigate whether ROS generated by specific mtDNA variants have the ability to alter expression of some key nuclear-encoded genes central to the wound healing response and oxidative stress. Our data suggest levels of mitochondrial ROS affect expression of some nuclear encoded genes central to wound healing response and oxidative stress and modulation of mitochondrial ROS by antioxidants positively affects in vitro process of wound closure. Thus, regulation of mitochondrial ROS-generating system in fibroblasts can be used as effective natural redox-based strategy to help treat non-healing wounds.

NPRL-Z-1, as a new topoisomerase II poison, induces cell apoptosis and ROS generation in human renal carcinoma cells.

Science.gov (United States)

Wu, Szu-Ying; Pan, Shiow-Lin; Xiao, Zhi-Yan; Hsu, Jui-Ling; Chen, Mei-Chuan; Lee, Kuo-Hsiung; Teng, Che-Ming

2014-01-01

NPRL-Z-1 is a 4β-[(4"-benzamido)-amino]-4'-O-demethyl-epipodophyllotoxin derivative. Previous reports have shown that NPRL-Z-1 possesses anticancer activity. Here NPRL-Z-1 displayed cytotoxic effects against four human cancer cell lines (HCT 116, A549, ACHN, and A498) and exhibited potent activity in A498 human renal carcinoma cells, with an IC50 value of 2.38 µM via the MTT assay. We also found that NPRL-Z-1 induced cell cycle arrest in G1-phase and detected DNA double-strand breaks in A498 cells. NPRL-Z-1 induced ataxia telangiectasia-mutated (ATM) protein kinase phosphorylation at serine 1981, leading to the activation of DNA damage signaling pathways, including Chk2, histone H2AX, and p53/p21. By ICE assay, the data suggested that NPRL-Z-1 acted on and stabilized the topoisomerase II (TOP2)-DNA complex, leading to TOP2cc formation. NPRL-Z-1-induced DNA damage signaling and apoptotic death was also reversed by TOP2α or TOP2β knockdown. In addition, NPRL-Z-1 inhibited the Akt signaling pathway and induced reactive oxygen species (ROS) generation. These results demonstrated that NPRL-Z-1 appeared to be a novel TOP2 poison and ROS generator. Thus, NPRL-Z-1 may present a significant potential anticancer candidate against renal carcinoma.

4-channel rad-hard delay generation ASIC with 1ns timing resolution for LHC

International Nuclear Information System (INIS)

Toifl, T.; Moreira, P.; Marchioro, A.; Vari, R.

1999-01-01

An ASIC was developed to precisely delay digital signals within the range of 0--24ns in steps of 1ns. To obtain well defined delay values independent of variations in process, supply voltage and temperature, four independent delay channels are controlled by a common control voltage derived from a delay-locked loop (DLL), which is synchronized to an external 40 MHz clock signal. The delay values of the four signal channels and the clock channel can be individually programmed via an I 2 C interface. Due to an automatic reset logic the chip does not need an external reset signal. A first version of the chip was developed in a non-rad-hard 0.8 microm technology and the successful prototype was then transferred to a radiation hard process (DMILL). Measurement results for both chip variants will be presented

Rosé wine volatile composition and the preferences of Chinese wine professionals.

Science.gov (United States)

Wang, Jiaming; Capone, Dimitra L; Wilkinson, Kerry L; Jeffery, David W

2016-07-01

Rosé wine aromas range from fruity and floral, to more developed, savoury characters. Lighter than red wines, rosé wines tend to match well with Asian cuisines, yet little is known about the factors driving desirability of rosé wines in emerging markets such as China. This study involved Chinese wine professionals participating in blind rosé wine tastings comprising 23 rosé wines from Australia, China and France in three major cities in China. According to the sensory results, a link between the preference, quality and expected retail price of the wines was observed, and assessors preferred wines with prominent red fruit, floral, confectionery and honey characters, and without developed attributes or too much sweetness. Basic wine chemical parameters and 47 volatile compounds, including 5 potent thiols, were determined. Correlations between chemical components, sensory attributes and preference/quality/expected price were visualised by network analysis, revealing relationships that are worthy of further investigation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Yeast signaling pathways in the oxidative stress response

Energy Technology Data Exchange (ETDEWEB)

Ikner, Aminah [Section of Microbiology, Division of Biological Sciences, University of California, Davis, CA 95616 (United States); Shiozaki, Kazuhiro [Section of Microbiology, Division of Biological Sciences, University of California, Davis, CA 95616 (United States)]. E-mail: kshiozaki@ucdavis.edu

2005-01-06

Oxidative stress that generates the reactive oxygen species (ROS) is one of the major causes of DNA damage and mutations. The 'DNA damage checkpoint' that arrests cell cycle and repairs damaged DNA has been a focus of recent studies, and the genetically amenable model systems provided by yeasts have been playing a leading role in the eukaryotic checkpoint research. However, means to eliminate ROS are likely to be as important as the DNA repair mechanisms in order to suppress mutations in the chromosomal DNA, and yeasts also serve as excellent models to understand how eukaryotes combat oxidative stress. In this article, we present an overview of the signaling pathways that sense oxidative stress and induce expression of various anti-oxidant genes in the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe and the pathogenic yeast Candida albicans. Three conserved signaling modules have been identified in the oxidative stress response of these diverse yeast species: the stress-responsive MAP kinase cascade, the multistep phosphorelay and the AP-1-like transcription factor. The structure and function of these signaling modules are discussed.

Yeast signaling pathways in the oxidative stress response

International Nuclear Information System (INIS)

Ikner, Aminah; Shiozaki, Kazuhiro

2005-01-01

Oxidative stress that generates the reactive oxygen species (ROS) is one of the major causes of DNA damage and mutations. The 'DNA damage checkpoint' that arrests cell cycle and repairs damaged DNA has been a focus of recent studies, and the genetically amenable model systems provided by yeasts have been playing a leading role in the eukaryotic checkpoint research. However, means to eliminate ROS are likely to be as important as the DNA repair mechanisms in order to suppress mutations in the chromosomal DNA, and yeasts also serve as excellent models to understand how eukaryotes combat oxidative stress. In this article, we present an overview of the signaling pathways that sense oxidative stress and induce expression of various anti-oxidant genes in the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe and the pathogenic yeast Candida albicans. Three conserved signaling modules have been identified in the oxidative stress response of these diverse yeast species: the stress-responsive MAP kinase cascade, the multistep phosphorelay and the AP-1-like transcription factor. The structure and function of these signaling modules are discussed

A preliminary cyber-physical security assessment of the Robot Operating System (ROS)

Science.gov (United States)

McClean, Jarrod; Stull, Christopher; Farrar, Charles; Mascareñas, David

2013-05-01

Over the course of the last few years, the Robot Operating System (ROS) has become a highly popular software framework for robotics research. ROS has a very active developer community and is widely used for robotics research in both academia and government labs. The prevalence and modularity of ROS cause many people to ask the question: "What prevents ROS from being used in commercial or government applications?" One of the main problems that is preventing this increased use of ROS in these applications is the question of characterizing its security (or lack thereof). In the summer of 2012, a crowd sourced cyber-physical security contest was launched at the cyber security conference DEF CON 20 to begin the process of characterizing the security of ROS. A small-scale, car-like robot was configured as a cyber-physical security "honeypot" running ROS. DEFFCON-20 attendees were invited to find exploits and vulnerabilities in the robot while network traffic was collected. The results of this experiment provided some interesting insights and opened up many security questions pertaining to deployed robotic systems. The Federal Aviation Administration is tasked with opening up the civil airspace to commercial drones by September 2015 and driverless cars are already legal for research purposes in a number of states. Given the integration of these robotic devices into our daily lives, the authors pose the following question: "What security exploits can a motivated person with little-to-no experience in cyber security execute, given the wide availability of free cyber security penetration testing tools such as Metasploit?" This research focuses on applying common, low-cost, low-overhead, cyber-attacks on a robot featuring ROS. This work documents the effectiveness of those attacks.

Redox Signaling in Diabetic Wound Healing Regulates Extracellular Matrix Deposition.

Science.gov (United States)

Kunkemoeller, Britta; Kyriakides, Themis R

2017-10-20

Impaired wound healing is a major complication of diabetes, and can lead to development of chronic foot ulcers in a significant number of patients. Despite the danger posed by poor healing, very few specific therapies exist, leaving patients at risk of hospitalization, amputation, and further decline in overall health. Recent Advances: Redox signaling is a key regulator of wound healing, especially through its influence on the extracellular matrix (ECM). Normal redox signaling is disrupted in diabetes leading to several pathological mechanisms that alter the balance between reactive oxygen species (ROS) generation and scavenging. Importantly, pathological oxidative stress can alter ECM structure and function. There is limited understanding of the specific role of altered redox signaling in the diabetic wound, although there is evidence that ROS are involved in the underlying pathology. Preclinical studies of antioxidant-based therapies for diabetic wound healing have yielded promising results. Redox-based therapeutics constitute a novel approach for the treatment of wounds in diabetes patients that deserve further investigation. Antioxid. Redox Signal. 27, 823-838.

Chemioxyexcitation (delta pO2/ROS)-dependent release of IL-1 beta, IL-6 and TNF-alpha: evidence of cytokines as oxygen-sensitive mediators in the alveolar epithelium.

Science.gov (United States)

Haddad, J J; Safieh-Garabedian, B; Saadé, N E; Kanaan, S A; Land, S C

2001-02-07

The signalling mechanisms in oxidative stress mediated by cytokines in the perinatal alveolar epithelium are not well known. In an in vitro model of fetal alveolar type II epithelial cells, we investigated the profile of cytokines in response to ascending Deltap O(2)regimen (oxyexcitation). The peak of TNF-alpha (4 h) preceded IL-1beta and IL-6 (6-9 h), indicating a positive feedback autocrine loop confirmed by exogenous rmTNF-alpha. Reactive oxygen species (ROS) induced a dose-dependent release of cytokines, an effect specifically obliterated by selective antioxidants of the hydroxyl radical (*OH) and superoxide anion (O(2)-). Actinomycin and cycloheximide blocked the induced production of cytokines, implicating transcriptional and translational control. Whilst the dismutating enzymes superoxide dismutase (SOD) and catalase were ineffective in reducing ROS-induced cytokines, MnP, a cell-permeating SOD mimetic, abrogated xanthine/xanthine oxidase-dependent cytokine release. Desferrioxamine mesylate, which inhibits the iron-catalysed generation of *OH via the Fenton reaction, exhibited a mild effect on the release of cytokines. Dynamic variation in alveolar p O(2)constitutes a potential signalling mechanism within the perinatal lung allowing upregulation of cytokines in an ROS-dependent manner. Copyright 2001 Academic Press.

Modulation of notch signaling pathway to prevent H2O2/menadione-induced SK-N-MC cells death by EUK134.

Science.gov (United States)

Kamarehei, Maryam; Yazdanparast, Razieh

2014-10-01

The brain in Alzheimer's disease is under increased oxidative stress, and this may have a role in the pathogenesis and neural death in this disorder. It has been verified that numerous signaling pathways involved in neurodegenerative disorders are activated in response to reactive oxygen species (ROS). EUK134, a synthetic salen-manganese antioxidant complex, has been found to possess many interesting pharmacological activities awaiting exploration. The present study is to characterize the role of Notch signaling in apoptotic cell death of SK-N-MC cells. The cells were treated with hydrogen peroxide (H2O2) or menadione to induce oxidative stress. The free-radical scavenging capabilities of EUK134 were studied through the MTT assay, glutathione peroxidase (GPx) enzyme activity assay, and glutathione (GSH) Levels. The extents of lipid peroxidation, protein carbonyl formation, and intracellular ROS levels, as markers of oxidative stress, were also studied. Our results showed that H2O2/menadione reduced GSH levels and GPx activity. However, EUK134 protected cells against ROS-induced cell death by down-regulation of lipid peroxidation and protein carbonyl formation as well as restoration of antioxidant enzymes activity. ROS induced apoptosis and increased NICD and HES1 expression. Inhibition of NICD production proved that Notch signaling is involved in apoptosis through p53 activation. Moreover, H2O2/menadione led to Numb protein down-regulation which upon EUK134 pretreatment, its level increased and subsequently prevented Notch pathway activation. We indicated that EUK134 can be a promising candidate in designing natural-based drugs for ROS-induced neurodegenerative diseases. Collectively, ROS activated Notch signaling in SK-N-MC cells leading to cell apoptosis.

Mitochondrion-Permeable Antioxidants to Treat ROS-Burst-Mediated Acute Diseases

Directory of Open Access Journals (Sweden)

Zhong-Wei Zhang

2016-01-01

Full Text Available Reactive oxygen species (ROS play a crucial role in the inflammatory response and cytokine outbreak, such as during virus infections, diabetes, cancer, cardiovascular diseases, and neurodegenerative diseases. Therefore, antioxidant is an important medicine to ROS-related diseases. For example, ascorbic acid (vitamin C, VC was suggested as the candidate antioxidant to treat multiple diseases. However, long-term use of high-dose VC causes many side effects. In this review, we compare and analyze all kinds of mitochondrion-permeable antioxidants, including edaravone, idebenone, α-Lipoic acid, carotenoids, vitamin E, and coenzyme Q10, and mitochondria-targeted antioxidants MitoQ and SkQ and propose astaxanthin (a special carotenoid to be the best antioxidant for ROS-burst-mediated acute diseases, like avian influenza infection and ischemia-reperfusion. Nevertheless, astaxanthins are so unstable that most of them are inactivated after oral administration. Therefore, astaxanthin injection is suggested hypothetically. The drawbacks of the antioxidants are also reviewed, which limit the use of antioxidants as coadjuvants in the treatment of ROS-associated disorders.

Menadione 処理した Candida albicans ROS 生産機構の解析

OpenAIRE

上野, 将明; 小笠原, 綾子; 渡部, 俊彦; 三上, 健; 松本, 達二; ウエノ, ユキヒロ; オガサワラ, アヤコ; ワタナベ, トシユキ; ミカミ, タケシ; マツモト, タツジ; Yukihiro, UENO; Ayako, OGASAWARA; Toshihiko, WATANABE; Takeshi, MIKAMI; Tatsuji, MATSUMOTO

2008-01-01

Menadione shows anti Condida activity by promoting ROS production. However, the ROS production mechanism has not been clarifield. Thus, in this study, we studied thr relation between anti Candida activity of menadione and ROS production. Menadione inhibited the growth of C. albicans BWP17 strain, the growth of C. albicans JM02 strain was not inhibited. ROS production in C. albicans BWP17 strain was enhanced by addition of menadione. The ROS production in C. albicans JM02 strain was also enhan...

TiO{sub 2} nanoparticle-induced ROS correlates with modulated immune cell function

Energy Technology Data Exchange (ETDEWEB)

Maurer-Jones, Melissa A.; Christenson, Jenna R.; Haynes, Christy L., E-mail: chaynes@umn.edu [University of Minnesota, Department of Chemistry (United States)

2012-12-15

Design of non-toxic nanoparticles will be greatly facilitated by understanding the nanoparticle-cell interaction mechanism on a cell function level. Mast cells are important cells for the immune system's first line of defense, and we can utilize their exocytotic behavior as a model cellular function as it is a conserved process across cell types and species. Perturbations in exocytosis can also have implications for whole organism health. One proposed mode of toxicity is nanoparticle-induced reactive oxygen species (ROS), particularly for titanium dioxide (TiO{sub 2}) nanoparticles. Herein, we have correlated changes in ROS with the perturbation of the critical cell function of exocytosis, using UV light to induce greater levels of ROS in TiO{sub 2} exposed cells. The primary culture mouse peritoneal mast cells (MPMCs) were exposed to varying concentrations of TiO{sub 2} nanoparticles for 24 h. ROS content was determined using 2,7-dihydrodichlorofluorescein diacetate (DCFDA). Cellular viability was determined with the MTT and Trypan blue assays, and exocytosis was measured by the analytical electrochemistry technique of carbon-fiber microelectrode amperometry. MPMCs exposed to TiO{sub 2} nanoparticles experienced a dose-dependent increase in total ROS content. While there was minimal impact of ROS on cellular viability, there is a correlation between ROS amount and exocytosis perturbation. As nanoparticle-induced ROS increases, there is a significant decrease (45 %) in the number of serotonin molecules being released during exocytosis, increase (26 %) in the amount of time for each exocytotic granule to release, and decrease (28 %) in the efficiency of granule trafficking and docking. This is the first evidence that nanoparticle-induced ROS correlates with chemical messenger molecule secretion, possibly making a critical connection between functional impairment and mechanisms contributing to that impairment.

Kaempferol inhibits the production of ROS to modulate OPN-αvβ3 integrin pathway in HUVECs.

Science.gov (United States)

Xiao, Hong-Bo; Lu, Xiang-Yang; Liu, Zi-Kui; Luo, Zhi-Feng

2016-06-01

In the present study, we tested the hypothesis that aldosterone regulates osteopontin (OPN)-related signaling pathways to promote nuclear factor κB (NF-κB) activation in primary human umbilical vein endothelial cells (HUVECs) and that kaempferol, a flavonoid compound, blocks those changes. Aldosterone induced productions of reactive oxygen species (ROS), OPN, interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α) and expression of nicotinamide adenine dinucleotide phosphate-oxidase 4 (Nox4), NF-κB, OPN, alphavbeta3 (αvβ3) integrin, and inhibitor of NF-κB alpha phosphorylation (P-IκBα) in HUVEC. HUVECs were pretreated with kaempferol (0, 1, 3, or 10 μM) for 1 h and exposed to aldosterone (10(-6) M) for 24 h. Kaempferol reduced ROS, OPN, NF-κB, IL-6, and TNF-α levels; Nox4, αvβ3 integrin; and P-IκBα expressions. The effect of aldosterone was also abrogated by spironolactone (10(-6) M). In addition, vitamin C (20 mmol/L) reduced ROS production. Vitamin C and LM609 (10 μg/mL) treatment decreased expressions of OPN, αvβ3 integrin, and NF-κB (P kaempferol may modulate OPN-αvβ3 integrin pathway to inhibit NF-κB activation in HUVECs.

High level of chromosomal instability in circulating tumor cells of ROS1-rearranged non-small-cell lung cancer.

Science.gov (United States)

Pailler, E; Auger, N; Lindsay, C R; Vielh, P; Islas-Morris-Hernandez, A; Borget, I; Ngo-Camus, M; Planchard, D; Soria, J-C; Besse, B; Farace, F

2015-07-01

Genetic aberrations affecting the c-ros oncogene 1 (ROS1) tyrosine kinase gene have been reported in a small subset of patients with non-small-cell lung cancer (NSCLC). We evaluated whether ROS1-chromosomal rearrangements could be detected in circulating tumor cells (CTCs) and examined tumor heterogeneity of CTCs and tumor biopsies in ROS1-rearranged NSCLC patients. Using isolation by size of epithelial tumor cells (ISET) filtration and filter-adapted-fluorescence in situ hybridization (FA-FISH), ROS1 rearrangement was examined in CTCs from four ROS1-rearranged patients treated with the ROS1-inhibitor, crizotinib, and four ROS1-negative patients. ROS1-gene alterations observed in CTCs at baseline from ROS1-rearranged patients were compared with those present in tumor biopsies and in CTCs during crizotinib treatment. Numerical chromosomal instability (CIN) of CTCs was assessed by DNA content quantification and chromosome enumeration. ROS1 rearrangement was detected in the CTCs of all four patients with ROS1 rearrangement previously confirmed by tumor biopsy. In ROS1-rearranged patients, median number of ROS1-rearranged CTCs at baseline was 34.5 per 3 ml blood (range, 24-55). In ROS1-negative patients, median background hybridization of ROS1-rearranged CTCs was 7.5 per 3 ml blood (range, 7-11). Tumor heterogeneity, assessed by ROS1 copy number, was significantly higher in baseline CTCs compared with paired tumor biopsies in the three patients experiencing PR or SD (P < 0.0001). Copy number in ROS1-rearranged CTCs increased significantly in two patients who progressed during crizotinib treatment (P < 0.02). CTCs from ROS1-rearranged patients had a high DNA content and gain of chromosomes, indicating high levels of aneuploidy and numerical CIN. We provide the first proof-of-concept that CTCs can be used for noninvasive and sensitive detection of ROS1 rearrangement in NSCLC patients. CTCs from ROS1-rearranged patients show considerable heterogeneity of ROS1-gene

Integrable microwave filter based on a photonic crystal delay line.

Science.gov (United States)

Sancho, Juan; Bourderionnet, Jerome; Lloret, Juan; Combrié, Sylvain; Gasulla, Ivana; Xavier, Stephane; Sales, Salvador; Colman, Pierre; Lehoucq, Gaelle; Dolfi, Daniel; Capmany, José; De Rossi, Alfredo

2012-01-01

The availability of a tunable delay line with a chip-size footprint is a crucial step towards the full implementation of integrated microwave photonic signal processors. Achieving a large and tunable group delay on a millimetre-sized chip is not trivial. Slow light concepts are an appropriate solution, if propagation losses are kept acceptable. Here we use a low-loss 1.5 mm-long photonic crystal waveguide to demonstrate both notch and band-pass microwave filters that can be tuned over the 0-50-GHz spectral band. The waveguide is capable of generating a controllable delay with limited signal attenuation (total insertion loss below 10 dB when the delay is below 70 ps) and degradation. Owing to the very small footprint of the delay line, a fully integrated device is feasible, also featuring more complex and elaborate filter functions.

33 CFR 117.9 - Delaying opening of a draw.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Delaying opening of a draw. 117.9... DRAWBRIDGE OPERATION REGULATIONS General Requirements § 117.9 Delaying opening of a draw. No person shall unreasonably delay the opening of a draw after the signals required by § 117.15 have been given. Note: Trains...

Dynamics of Nonlinear Time-Delay Systems

CERN Document Server

Lakshmanan, Muthusamy

2010-01-01

Synchronization of chaotic systems, a patently nonlinear phenomenon, has emerged as a highly active interdisciplinary research topic at the interface of physics, biology, applied mathematics and engineering sciences. In this connection, time-delay systems described by delay differential equations have developed as particularly suitable tools for modeling specific dynamical systems. Indeed, time-delay is ubiquitous in many physical systems, for example due to finite switching speeds of amplifiers in electronic circuits, finite lengths of vehicles in traffic flows, finite signal propagation times in biological networks and circuits, and quite generally whenever memory effects are relevant. This monograph presents the basics of chaotic time-delay systems and their synchronization with an emphasis on the effects of time-delay feedback which give rise to new collective dynamics. Special attention is devoted to scalar chaotic/hyperchaotic time-delay systems, and some higher order models, occurring in different bran...

Troglitazone induced apoptosis via PPARγ activated POX-induced ROS formation in HT29 cells.

Science.gov (United States)

Wang, Jing; Lv, XiaoWen; Shi, JiePing; Hu, XiaoSong; DU, YuGuo

2011-08-01

In order to investigate the potential mechanisms in troglitazone-induced apoptosis in HT29 cells, the effects of PPARγ and POX-induced ROS were explored. [3- (4, 5)-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay, Annexin V and PI staining using FACS, plasmid transfection, ROS formation detected by DCFH staining, RNA interference, RT-PCR & RT-QPCR, and Western blotting analyses were employed to investigate the apoptotic effect of troglitazone and the potential role of PPARγ pathway and POX-induced ROS formation in HT29 cells. Troglitazone was found to inhibit the growth of HT29 cells by induction of apoptosis. During this process, mitochondria related pathways including ROS formation, POX expression and cytochrome c release increased, which were inhibited by pretreatment with GW9662, a specific antagonist of PPARγ. These results illustrated that POX upregulation and ROS formation in apoptosis induced by troglitazone was modulated in PPARγ-dependent pattern. Furthermore, the inhibition of ROS and apoptosis after POX siRNA used in troglitazone-treated HT29 cells indicated that POX be essential in the ROS formation and PPARγ-dependent apoptosis induced by troglitazone. The findings from this study showed that troglitazone-induced apoptosis was mediated by POX-induced ROS formation, at least partly, via PPARγ activation. Copyright © 2011 The Editorial Board of Biomedical and Environmental Sciences. Published by Elsevier B.V. All rights reserved.

SERPINA3K plays antioxidant roles in cultured pterygial epithelial cells through regulating ROS system.

Directory of Open Access Journals (Sweden)

Chengpeng Zhu

Full Text Available We recently demonstrated that SERPINA3K, a serine proteinase inhibitor, has antioxidant activity in the cornea. Here we investigated the antioxidant effects of SERPINA3K on the pterygial, which is partially caused by oxidative stress in pathogenesis. The head part of primary pterygial tissue was dissected and then cultured in keratinocyte serum-free defined medium (KSFM. The cultured pterygial epithelial cells (PECs were treated with SERPINA3K. The cell proliferation and migration of PECs were measured and analyzed. Western blot and quantitative real-time polymerase chain reaction (PCR assay were performed. It showed that SERPINA3K significantly suppressed the cell proliferation of PECs in a concentration-dependent manner, compared with cultured human conjunctival epithelial cells. SERPINA3K also inhibited the cell migration of PECs. Towards its underlying mechanism, SERPINA3K had antioxidant activities on the PECs by significantly inhibiting NADPH oxidase 4 (NOX4, which is an important enzyme of ROS generation, and by elevating the levels of key antioxidant factors of ROS: such as NAD(PH dehydrogenase (quinone 1 (NQO1, NF-E2-related factor-2 (NRF2 and superoxide dismutases (SOD2. Meanwhile, SERPINA3K down-regulated the key effectors of Wnt signaling pathway: β-catenin, nonphospho-β-catenin, and low-density lipoprotein receptor-related protein 6 (LRP6. We provided novel evidence that SERPINA3K had inhibitory effects on pterygium and SERPINA3K played antioxidant role via regulating the ROS system and antioxidants.

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

Science.gov (United States)

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

2013-03-01

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

Menadione triggers cell death through ROS-dependent mechanisms involving PARP activation without requiring apoptosis.

Science.gov (United States)

Loor, Gabriel; Kondapalli, Jyothisri; Schriewer, Jacqueline M; Chandel, Navdeep S; Vanden Hoek, Terry L; Schumacker, Paul T

2010-12-15

Low levels of reactive oxygen species (ROS) can function as redox-active signaling messengers, whereas high levels of ROS induce cellular damage. Menadione generates ROS through redox cycling, and high concentrations trigger cell death. Previous work suggests that menadione triggers cytochrome c release from mitochondria, whereas other studies implicate the activation of the mitochondrial permeability transition pore as the mediator of cell death. We investigated menadione-induced cell death in genetically modified cells lacking specific death-associated proteins. In cardiomyocytes, oxidant stress was assessed using the redox sensor RoGFP, expressed in the cytosol or the mitochondrial matrix. Menadione elicited rapid oxidation in both compartments, whereas it decreased mitochondrial potential and triggered cytochrome c redistribution to the cytosol. Cell death was attenuated by N-acetylcysteine and exogenous glutathione or by overexpression of cytosolic or mitochondria-targeted catalase. By contrast, no protection was observed in cells overexpressing Cu,Zn-SOD or Mn-SOD. Overexpression of antiapoptotic Bcl-X(L) protected against staurosporine-induced cell death, but it failed to confer protection against menadione. Genetic deletion of Bax and Bak, cytochrome c, cyclophilin D, or caspase-9 conferred no protection against menadione-induced cell death. However, cells lacking PARP-1 showed a significant decrease in menadione-induced cell death. Thus, menadione induces cell death through the generation of oxidant stress in multiple subcellular compartments, yet cytochrome c, Bax/Bak, caspase-9, and cyclophilin D are dispensable for cell death in this model. These studies suggest that multiple redundant cell death pathways are activated by menadione, but that PARP plays an essential role in mediating each of them. Copyright © 2010 Elsevier Inc. All rights reserved.

Proposition of delay model for signalized intersections with queueing theory analytical models usage

Directory of Open Access Journals (Sweden)

Grzegorz SIERPIŃSKI

2007-01-01

Full Text Available Time delay on intersections is a very important transport problem. Thearticle includes a proposition of time delay model. Variance of service times is considered by used average waiting time in queue for queuing system with compressed queuing processes usage as a part of proposed time delays model.

Helicobacter pylori induces IL-1β and IL-18 production in human monocytic cell line through activation of NLRP3 inflammasome via ROS signaling pathway.

Science.gov (United States)

Li, Xiang; Liu, Sheng; Luo, Jingjing; Liu, Anyuan; Tang, Shuangyang; Liu, Shuo; Yu, Minjun; Zhang, Yan

2015-06-01

This study investigated whether Helicobacter pylori could activate the nucleotide-binding oligomerization domain-like receptor (NLR) family, pyrin domain-containing 3 (NLRP3) inflammasome in human macrophages and the involvement of reactive oxygen species (ROS) in inflammasome activation. Phorbol-12-myristate-13-acetate (PMA)-differentiated human acute monocytic leukemia cell line THP-1 was infected with H. pylori. The levels of pro-inflammatory cytokines interleukin (IL)-1β and IL-18 in supernatant were measured by ELISA. Intracellular ROS level was analyzed by flow cytometry. Quantitative real-time PCR and western blot analysis were employed to determine the mRNA and protein expression levels of NLRP3 and caspase-1 in THP-1 cells, respectively. Our results showed that H. pylori infection could induce IL-1β and IL-18 production in PMA-differentiated THP-1 cells in a dose- and time-dependent manner. Moreover, secretion of IL-1β and IL-18 in THP-1 cells following H. pylori infection was remarkably reduced by NLRP3-specific small interfering RNA treatment. In addition, the intracellular ROS level was elevated by H. pylori infection, which could be eliminated by the ROS scavenger N-acetylcysteine (NAC). Furthermore, NAC treatment could inhibit NLRP3 inflammasome formation and caspase-1 activation and suppress the release of IL-1β and IL-18 from H. pylori-infected THP-1 cells. These findings provide novel insights into the innate immune response against H. pylori infection, which could potentially be used for the prevention and treatment of H. pylori-related diseases. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

NOX4-mediated ROS production induces apoptotic cell death via down-regulation of c-FLIP and Mcl-1 expression in combined treatment with thioridazine and curcumin

Directory of Open Access Journals (Sweden)

Seung Un Seo

2017-10-01

Full Text Available Thioridazine is known to have anti-tumor effects by inhibiting PI3K/Akt signaling, which is an important signaling pathway in cell survival. However, thioridazine alone does not induce apoptosis in head and neck squamous cell carcinoma (AMC-HN4, human breast carcinoma (MDA-MB231, and human glioma (U87MG cells. Therefore, we investigated whether combined treatment with thioridazine and curcumin induces apoptosis. Combined treatment with thioridazine and curcumin markedly induced apoptosis in cancer cells without inducing apoptosis in human normal mesangial cells and human normal umbilical vein cells (EA.hy926. We found that combined treatment with thioridazine and curcumin had synergistic effects in AMC-HN4 cells. Among apoptosis-related proteins, thioridazine plus curcumin induced down-regulation of c-FLIP and Mcl-1 expression at the post-translational levels in a proteasome-dependent manner. Augmentation of proteasome activity was related to the up-regulation of proteasome subunit alpha 5 (PSMA5 expression in curcumin plus thioridazine-treated cells. Combined treatment with curcumin and thioridazine produced intracellular ROS in a NOX4-dependent manner, and ROS-mediated activation of Nrf2/ARE signaling played a critical role in the up-regulation of PSMA5 expression. Furthermore, ectopic expression of c-FLIP and Mcl-1 inhibited apoptosis in thioridazine and curcumin-treated cells. Therefore, we demonstrated that thioridazine plus curcumin induces proteasome activity by up-regulating PSMA5 expression via NOX4-mediated ROS production and that down-regulation of c-FLIP and Mcl-1 expression post-translationally is involved in apoptosis.

Automated delay estimation at signalized intersections : phase I concept and algorithm development.

Science.gov (United States)

2011-07-01

Currently there are several methods to measure the performance of surface streets, but their capabilities in dynamically estimating vehicle delay are limited. The objective of this research is to develop a method to automate traffic delay estimation ...

Production of Superoxide in Bacteria Is Stress- and Cell State-Dependent: A Gating-Optimized Flow Cytometry Method that Minimizes ROS Measurement Artifacts with Fluorescent Dyes.

Science.gov (United States)

McBee, Megan E; Chionh, Yok H; Sharaf, Mariam L; Ho, Peiying; Cai, Maggie W L; Dedon, Peter C

2017-01-01

The role of reactive oxygen species (ROS) in microbial metabolism and stress response has emerged as a major theme in microbiology and infectious disease. Reactive fluorescent dyes have the potential to advance the study of ROS in the complex intracellular environment, especially for high-content and high-throughput analyses. However, current dye-based approaches to measuring intracellular ROS have the potential for significant artifacts. Here, we describe a robust platform for flow cytometric quantification of ROS in bacteria using fluorescent dyes, with ROS measurements in 10s-of-1000s of individual cells under a variety of conditions. False positives and variability among sample types (e.g., bacterial species, stress conditions) are reduced with a flexible four-step gating scheme that accounts for side- and forward-scattered light (morphological changes), background fluorescence, DNA content, and dye uptake to identify cells producing ROS. Using CellROX Green dye with Escherichia coli, Mycobacterium smegmatis , and Mycobacterium bovis BCG as diverse model bacteria, we show that (1) the generation of a quantifiable CellROX Green signal for superoxide, but not hydrogen peroxide-induced hydroxyl radicals, validates this dye as a superoxide detector; (2) the level of dye-detectable superoxide does not correlate with cytotoxicity or antibiotic sensitivity; (3) the non-replicating, antibiotic tolerant state of nutrient-deprived mycobacteria is associated with high levels of superoxide; and (4) antibiotic-induced production of superoxide is idiosyncratic with regard to both the species and the physiological state of the bacteria. We also show that the gating method is applicable to other fluorescent indicator dyes, such as the 5-carboxyfluorescein diacetate acetoxymethyl ester and 5-cyano-2,3-ditolyl tetrazolium chloride for cellular esterase and reductive respiratory activities, respectively. These results demonstrate that properly controlled flow cytometry coupled

SUSTANCIAS OXÍGENO REACTIVAS (ROS EN SEMEN CONGELADO-DESCONGELADO DE PORCINO

Directory of Open Access Journals (Sweden)

Diana Vasco Mora

2008-06-01

Full Text Available La generación de ROS fue medida por citometría de flujo en muestras espermáticas descongeladas incubadas sin (niveles basales o con (niveles inducidos un inductor de ROS (1 mM de tert-butyl hidroperóxido por 30 min a 39 °C y 5% de CO2. Además, fueron simultáneamente teñidas con 2’, 7’-diacetato de diclorodihidrofluoresceína, acetil ester (1 mM, CM-H2DCFDA, para estimar la producción de ROS e, ioduro de propidio (1.5 mM para excluir la población espermática muerta. Los eyaculados de nueve verracos fueron congelados con 3% de glicerol y descongelados a ≈1200 ó ≈1800 ºC min-1. La producción de ROS fue medida a los 0, 60, 120, 240 y 360 min en muestras mantenidas a 21-23 °C (no incubadas, o a 39 ºC y 5% de CO2 (incubadas. La velocidad de descongelación no registró influencia (P>0.05 sobre la producción de ROS. La generación de ROS fue constante (P>0.05 en el tiempo en las muestras no incubadas, pero mostró un incremento progresivo en las muestras incubadas, siendo significativa (P<0.05 desde los 120 min en niveles basales ó 60 min de incubación en niveles inducidos. Además, una significativa variabilidad eyaculado/verraco fue evidente, tanto en niveles basales como inducidos en las muestras incubadas. La producción de ROS basal e inducida estuvo significativamente (P<0.01 correlacionada con la calidad espermática. La técnica utilizada es de gran utilidad para evaluar capacidad funcional en espermatozoides congelados-descongelados; sin embargo, se requieren estudios adicionales para estandarizar la misma y establecer umbrales indicativos de pérdida de calidad espermática.

Geometric patterns of time-delay plots from different cardiac rhythms and arrhythmias using short-term EKG signals.

Science.gov (United States)

Borracci, Raúl A; Montoya Pulvet, José D; Ingino, Carlos A; Fitz Maurice, Mario; Hirschon Prado, Alfredo; Dominé, Enrique

2017-12-27

To date, no systematic work has been intended to describe spatio-temporal patterns of cardiac rhythms using only short series of RR intervals, to facilitate visual or computerized-aided identification of EKG motifs for use in clinical practice. The aim of this study was to detect and classify eye-catching geometric patterns of Poincaré time-delay plots from different types of cardiac rhythms and arrhythmias using short-term EKG signals. Approximately 150-300 representative, consecutive beats were retrieved from 24-h Holter registers of 100 patients with different heart rhythms. Two-dimensional Poincaré charts were created, and the resulting geometric patterns were transformed into representative familiar eye-catching drawings to interpret different arrhythmias. Poincaré plot representation of RR interval data revealed a wide variety of visual patterns: (i) comet-shaped for sinus rhythm; (ii) torpedo-shaped for sinus bradycardia; (iii) cigarette-shaped for sinus tachycardia; (iv) butterfly-shaped for sinus tachycardia and isolated atrial premature complexes; (v) arrow-shaped for isolated premature complexes and inappropriate sinus tachycardia; (vi) inverted fan-shaped for sinus rhythm with frequent atrial premature complexes; (vii) tornado-shaped for atrial flutter and atrial tachycardia; and (viii) fan-shaped for atrial fibrillation. Modified Poincaré plots with smoothed lines connecting successive points could accurately classify different types of arrhythmias based on short RR interval sequence variability. Characteristic emergent patterns can be visually identified and eventually could be distinguished by an automatic classification system able to discern between arrhythmias. This work provides an alternative method to interpret time-delay plots obtained from short-term EKG signal recordings. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Probe for intracellular concentrations of drugs: delayed fluorescence from acridine orange

International Nuclear Information System (INIS)

Wardman, P.; Dennis, M.F.; White, J.

1989-01-01

The aim of this work is to develop fluorescent probes that will indicate effective concentrations of therapeutic agents, or endogenous protectors, at important cellular sites. Acridine orange associates with nucleic acids and emits a 'delayed' fluorescence signal. This signal is quenched by oxidants such as oxygen, nitroaryl radiosensitizers, adriamycin and mitomycin-c, and reductants such as thiols, ascorbate and other radioprotectors. The quenching of the acridine orange delayed fluorescence reflects the effective concentration of these therapeutically-important oxidants and reductants near DNA. The relative concentration of basic radiosensitizers such as pimonidazole (Ro 03-8799) near the DNA is greater than that of misonidazole. Thiols quench the delayed fluorescence signal according to the degree of ionization of the thiol function; this may model the reactivity of thiols with guanine radical sites in DNA. Ascorbate and aminopyrine do not quench the delayed fluorescence from cells stained with acridine orange as these compounds are taken up by cells very inefficiently

A pedagogia do Rosário, conteúdo educativo da festa: estudo do potencial pedagógico contido na festa de Nossa Senhora do Rosário

OpenAIRE

Maria das Merces Bonfim Ambrosio

1989-01-01

Elaborado como dissertação de Mestrado em educação, "A Pedagogia do Rosário-caráter educativo da Festa", objetivou desvendar os conteúdos educativos presentes na Festa de Nossa Senhora do Rosário, em Sete Lagoas-MG. Através da participação nesses eventos, nos anos de 1981 e 1982 e de entrevistas com membros das guardas de Nossa Senhora do rosário naquela cidade- além de leitura orientada-foi possível traçar as linhas dessa pedagogia, presentes neste trabalho. Trata-se de uma manifestação cult...

ROS evaluation for a series of CNTs and their derivatives using an ESR method with DMPO

International Nuclear Information System (INIS)

Tsuruoka, S; Noguchi, T; Endo, M; Tristan, F; Terrones, M; Takeuchi, K; Koyama, K; Usui, Y; Matsumoto, H; Saito, N; Porter, D W; Castranova, V

2013-01-01

Carbon nanotubes (CNTs) are important materials in advanced industries. It is a concern that pulmonary exposure to CNTs may induce carcinogenic responses. It has been recently reported that CNTs scavenge ROS though non-carbon fibers generate ROS. A comprehensive evaluation of ROS scavenging using various kinds of CNTs has not been demonstrated well. The present work specifically investigates ROS scavenging capabilities with a series of CNTs and their derivatives that were physically treated, and with the number of commercially available CNTs. CNT concentrations were controlled at 0.2 through 0.6 wt%. The ROS scavenging rate was measured by ESR with DMPO. Interestingly, the ROS scavenging rate was not only influenced by physical treatments, but was also dependent on individual manufacturing methods. Ratio of CNTs to DMPO/ hydrogen peroxide is a key parameter to obtain appropriate ROS quenching results for comparison of CNTs. The present results suggest that dangling bonds are not a sole factor for scavenging, and electron transfer on the CNT surface is not clearly determined to be the sole mechanism to explain ROS scavenging.

ROS evaluation for a series of CNTs and their derivatives using an ESR method with DMPO.

Science.gov (United States)

Tsuruoka, S; Takeuchi, K; Koyama, K; Noguchi, T; Endo, M; Tristan, F; Terrones, M; Matsumoto, H; Saito, N; Usui, Y; Porter, D W; Castranova, V

Carbon nanotubes (CNTs) are important materials in advanced industries. It is a concern that pulmonary exposure to CNTs may induce carcinogenic responses. It has been recently reported that CNTs scavenge ROS though non-carbon fibers generate ROS. A comprehensive evaluation of ROS scavenging using various kinds of CNTs has not been demonstrated well. The present work specifically investigates ROS scavenging capabilities with a series of CNTs and their derivatives that were physically treated, and with the number of commercially available CNTs. CNT concentrations were controlled at 0.2 through 0.6 wt%. The ROS scavenging rate was measured by ESR with DMPO. Interestingly, the ROS scavenging rate was not only influenced by physical treatments, but was also dependent on individual manufacturing methods. Ratio of CNTs to DMPO/ hydrogen peroxide is a key parameter to obtain appropriate ROS quenching results for comparison of CNTs. The present results suggest that dangling bonds are not a sole factor for scavenging, and electron transfer on the CNT surface is not clearly determined to be the sole mechanism to explain ROS scavenging.

Cambogin Induces Caspase-Independent Apoptosis through the ROS/JNK Pathway and Epigenetic Regulation in Breast Cancer Cells.

Science.gov (United States)

Shen, Kaikai; Xie, Jianling; Wang, Hua; Zhang, Hong; Yu, Mengyuan; Lu, Fangfang; Tan, Hongsheng; Xu, Hongxi

2015-07-01

Cambogin is a polycyclic polyprenylated acylphoroglucinol (PPAP) from the Garcinia genus, which has been used traditionally for cancer treatment across Southeastern Asia. In this study, we found that cambogin inhibited breast cancer cell proliferation and induced cell apoptosis in vitro. Cambogin induced the activation of the caspase-independent mitochondrial apoptotic pathway, as indicated by an increase in the ratio of Bax/Bcl-2 and the nuclear translocation of apoptosis inducing factor (AIF). Two-dimensional gel electrophoresis and mass spectrometry revealed that the expression of proteins involving in the radical oxygen species (ROS) pathway was among the most affected upon cambogin treatment. Cambogin enhanced cellular ROS production, and induced the activation of the ASK1-MKK4/MKK7-JNK/SAPK signaling pathway. Pretreatment with ROS scavenger N-acetylcysteine (NAC), an antioxidant, or the JNK inhibitor SP600125 was able to restore cell viability in the presence of cambogin. Importantly, cambogin treatment led to the activation of activating transcription factor-2 (ATF-2) and the trimethylation of histone H3K9 in the activator protein 1 (AP-1) binding region of the Bcl-2 gene promoter. Finally, cambogin exhibited a potential antitumor effect in MCF-7 breast cancer xenografts without apparent toxicity. Taken in conjunction, the present study indicates that cambogin can induce breast adenocarcinoma cell apoptosis and therefore represents therapeutic potential for cancer treatment. ©2015 American Association for Cancer Research.

A Prediction Model for ROS1-Rearranged Lung Adenocarcinomas based on Histologic Features

OpenAIRE

Zhou, Jianya; Zhao, Jing; Zheng, Jing; Kong, Mei; Sun, Ke; Wang, Bo; Chen, Xi; Ding, Wei; Zhou, Jianying

2016-01-01

Aims To identify the clinical and histological characteristics of ROS1-rearranged non-small-cell lung carcinomas (NSCLCs) and build a prediction model to prescreen suitable patients for molecular testing. Methods and Results We identified 27 cases of ROS1-rearranged lung adenocarcinomas in 1165 patients with NSCLCs confirmed by real-time PCR and FISH and performed univariate and multivariate analyses to identify predictive factors associated with ROS1 rearrangement and finally developed predi...

A review on high-resolution CMOS delay lines: towards sub-picosecond jitter performance.

Science.gov (United States)

Abdulrazzaq, Bilal I; Abdul Halin, Izhal; Kawahito, Shoji; Sidek, Roslina M; Shafie, Suhaidi; Yunus, Nurul Amziah Md

2016-01-01

A review on CMOS delay lines with a focus on the most frequently used techniques for high-resolution delay step is presented. The primary types, specifications, delay circuits, and operating principles are presented. The delay circuits reported in this paper are used for delaying digital inputs and clock signals. The most common analog and digitally-controlled delay elements topologies are presented, focusing on the main delay-tuning strategies. IC variables, namely, process, supply voltage, temperature, and noise sources that affect delay resolution through timing jitter are discussed. The design specifications of these delay elements are also discussed and compared for the common delay line circuits. As a result, the main findings of this paper are highlighting and discussing the followings: the most efficient high-resolution delay line techniques, the trade-off challenge found between CMOS delay lines designed using either analog or digitally-controlled delay elements, the trade-off challenge between delay resolution and delay range and the proposed solutions for this challenge, and how CMOS technology scaling can affect the performance of CMOS delay lines. Moreover, the current trends and efforts used in order to generate output delayed signal with low jitter in the sub-picosecond range are presented.

ROS accumulation by PEITC selectively kills ovarian cancer cells via UPR-mediated apoptosis

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Yoon-hee eHong

2015-07-01

Full Text Available Unfolded protein response (UPR is crucial for both survival and death of mammalian cells, which is regulated by reactive oxygen species (ROS and nutrient depletion. In this study, we demonstrated the effect of ROS-accumulation, induced by β-phenethyl isothiocyanate (PEITC, on UPR mediated apoptosis in ovarian cancer cells. We used ovarian cancer cell lines, PA-1 and SKOV-3, with different p53 status (wild- and null- type, respectively. PEITC caused increased ROS-accumulation and inhibited proliferation selectively in ovarian cancer cells, and glutathione (GSH depletion in SKOV-3. However, PEITC did not cause any effect in normal ovarian epithelial cells and peripheral blood mononuclear cells. After 48 h of PEITC treatment (5 µM, apoptotic cell death was shown to increase significantly in the ovarian cancer cells and not in the normal cells. The key regulator of UPR-mediated apoptosis, CHOP/GADD153 and ER resident chaperone BiP/GRP78 were parallely up-regulated with activation of two major sensors of the UPR (PERK and ATF-6 in PA-1; PERK, and IRE1α in SKOV-3 in response to ROS accumulation induced by PEITC (5 µM. ROS scavenger, N-acetyl-cysteine (NAC, attenuated the effect of PEITC on UPR signatures (P-PERK, IRE1α, CHOP/GADD153, and BiP/GRP78, suggesting the involvement of ROS in UPR-mediated apoptosis. Altogether, PEITC induces UPR-mediated apoptosis in ovarian cancer cells via accumulation of ROS in a cancer-specific manner.

River recreation experience opportunities in two recreation opportunity spectrum (ROS) classes

Science.gov (United States)

Duane C. Wollmuth; John H. Schomaker; Lawrence C. Merriam

1985-01-01

The Recreation Opportunity Spectrum (ROS) system is used by the USDA Forest Service and USDI Bureau of Land Management for inventorying, classifying, and managing wildlands for recreation. Different ROS classes from the Colorado and Arkansas Rivers in Colorado were compared, using visitor survey data collected in 1979 and 1981, to see if the different classes offered...

A procedure to correct the effects of a relative delay between the quadrature components of radar signals at base band

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Grydeland

2005-01-01

Full Text Available The real and imaginary parts of baseband signals are obtained from a real narrow-band signal by quadrature mixing, i.e. by mixing with cosine and sine signals at the narrow band's selected center frequency. We address the consequences of a delay between the outputs of the quadrature mixer, which arise when digital samples of the quadrature baseband signals are not synchronised, i.e. when the real and imaginary components have been shifted by one or more samples with respect to each other. Through analytical considerations and simulations of such an error on different synthetic signals, we show how this error can be expected to afflict different measurements. In addition, we show the effect of the error on actual incoherent scatter radar data obtained by two different digital receiver systems used in parallel at the EISCAT Svalbard Radar (ESR. The analytical considerations indicate a procedure to correct the error, albeit with some limitations due to a small singular region. We demonstrate the correction procedure on actually afflicted data and compare the results to simultaneously acquired unafflicted data. We also discuss the possible data analysis strategies, including some that avoid dealing directly with the singular region mentioned above.

Delayed-onset of procoagulant signalling revealed by kinetic analysis of COAT platelet formation.

Science.gov (United States)

Alberio, Lorenzo; Ravanat, Catherine; Hechler, Béatrice; Mangin, Pierre H; Lanza, François; Gachet, Christian

2017-06-02

The combined action of collagen and thrombin induces the formation of COAT platelets, which are characterised by a coat of procoagulant and adhesive molecules on their surface. Although recent work has started to highlight their clinical relevance, the exact mechanisms regulating the formation of procoagulant COAT platelets remain unclear. Therefore, we employed flow cytometry in order to visualise in real time surface and intracellular events following simultaneous platelet activation with convulxin and thrombin. After a rapid initial response pattern characterised by the homogenous activation of the fibrinogen receptor glycoprotein IIb/IIIa in all platelets, starting with a delay of about 2 minutes an increasing fraction transforms to procoagulant COAT platelets. Their surface is characterised by progressive loss of PAC-1 binding, expression of negative phospholipids and retention of α-granule von Willebrand factor. Intracellular events in procoagulant COAT platelets are a marked increase of free calcium into the low micromolar range, concomitantly with early depolarisation of the mitochondrial membrane and activation of caspase-3, while non-COAT platelets keep the intracellular free calcium in the nanomolar range and maintain an intact mitochondrial membrane. We show for the first time that the flow-cytometrically distinct fractions of COAT and non-COAT platelets differentially phosphorylate two signalling proteins, PKCα and p38MAPK, which may be involved in the regulation of the different calcium fluxes observed in COAT versus non-COAT platelets. This study demonstrates the utility of concomitant cellular and signalling evaluation using flow cytometry in order to further dissect the mechanisms underlying the dichotomous platelet response observed after collagen/thrombin stimulation.

Measurement of time delay for a prospectively gated CT simulator.

Science.gov (United States)

Goharian, M; Khan, R F H

2010-04-01

For the management of mobile tumors, respiratory gating is the ideal option, both during imaging and during therapy. The major advantage of respiratory gating during imaging is that it is possible to create a single artifact-free CT data-set during a selected phase of the patient's breathing cycle. The purpose of the present work is to present a simple technique to measure the time delay during acquisition of a prospectively gated CT. The time delay of a Philips Brilliance BigBore (Philips Medical Systems, Madison, WI) scanner attached to a Varian Real-Time Position Management (RPM) system (Varian Medical Systems, Palo Alto, CA) was measured. Two methods were used to measure the CT time delay: using a motion phantom and using a recorded data file from the RPM system. In the first technique, a rotating wheel phantom was altered by placing two plastic balls on its axis and rim, respectively. For a desired gate, the relative positions of the balls were measured from the acquired CT data and converted into corresponding phases. Phase difference was calculated between the measured phases and the desired phases. Using period of motion, the phase difference was converted into time delay. The Varian RPM system provides an external breathing signal; it also records transistor-transistor logic (TTL) 'X-Ray ON' status signal from the CT scanner in a text file. The TTL 'X-Ray ON' indicates the start of CT image acquisition. Thus, knowledge of the start time of CT acquisition, combined with the real-time phase and amplitude data from the external respiratory signal, provides time-stamping of all images in an axial CT scan. The TTL signal with time-stamp was used to calculate when (during the breathing cycle) a slice was recorded. Using the two approaches, the time delay between the prospective gating signal and CT simulator has been determined to be 367 +/- 40 ms. The delay requires corrections both at image acquisition and while setting gates for the treatment delivery

NOX4-mediated ROS production induces apoptotic cell death via down-regulation of c-FLIP and Mcl-1 expression in combined treatment with thioridazine and curcumin.

Science.gov (United States)

Seo, Seung Un; Kim, Tae Hwan; Kim, Dong Eun; Min, Kyoung-Jin; Kwon, Taeg Kyu

2017-10-01

Thioridazine is known to have anti-tumor effects by inhibiting PI3K/Akt signaling, which is an important signaling pathway in cell survival. However, thioridazine alone does not induce apoptosis in head and neck squamous cell carcinoma (AMC-HN4), human breast carcinoma (MDA-MB231), and human glioma (U87MG) cells. Therefore, we investigated whether combined treatment with thioridazine and curcumin induces apoptosis. Combined treatment with thioridazine and curcumin markedly induced apoptosis in cancer cells without inducing apoptosis in human normal mesangial cells and human normal umbilical vein cells (EA.hy926). We found that combined treatment with thioridazine and curcumin had synergistic effects in AMC-HN4 cells. Among apoptosis-related proteins, thioridazine plus curcumin induced down-regulation of c-FLIP and Mcl-1 expression at the post-translational levels in a proteasome-dependent manner. Augmentation of proteasome activity was related to the up-regulation of proteasome subunit alpha 5 (PSMA5) expression in curcumin plus thioridazine-treated cells. Combined treatment with curcumin and thioridazine produced intracellular ROS in a NOX4-dependent manner, and ROS-mediated activation of Nrf2/ARE signaling played a critical role in the up-regulation of PSMA5 expression. Furthermore, ectopic expression of c-FLIP and Mcl-1 inhibited apoptosis in thioridazine and curcumin-treated cells. Therefore, we demonstrated that thioridazine plus curcumin induces proteasome activity by up-regulating PSMA5 expression via NOX4-mediated ROS production and that down-regulation of c-FLIP and Mcl-1 expression post-translationally is involved in apoptosis. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Complex-enhanced chaotic signals with time-delay signature suppression based on vertical-cavity surface-emitting lasers subject to chaotic optical injection

Science.gov (United States)

Chen, Jianjun; Duan, Yingni; Zhong, Zhuqiang

2018-03-01

A chaotic system is constructed on the basis of vertical-cavity surface-emitting lasers (VCSELs), where a slave VCSEL subject to chaotic optical injection (COI) from a master VCSEL with the external feedback. The complex degree (CD) and time-delay signature (TDS) of chaotic signals generated by this chaotic system are investigated numerically via permutation entropy (PE) and self-correlation function (SF) methods, respectively. The results show that, compared with master VCSEL subject to optical feedback, complex-enhanced chaotic signals with TDS suppression can be achieved for S-VCSEL subject to COI. Meanwhile, the influences of several controllable parameters on the evolution maps of CD of chaotic signals are carefully considered. It is shown that the CD of chaotic signals for S-VCSEL is always higher than that for M-VCSEL due to the CIO effect. The TDS of chaotic signals can be significantly suppressed by choosing the reasonable parameters in this system. Furthermore, TDS suppression and high CD chaos can be obtained simultaneously in the specific parameter ranges. The results confirm that this chaotic system may effectively improve the security of a chaos-based communication scheme.

Transmission delays in hardware clock synchronization

Science.gov (United States)

Shin, Kang G.; Ramanathan, P.

1988-01-01

Various methods, both with software and hardware, have been proposed to synchronize a set of physical clocks in a system. Software methods are very flexible and economical but suffer an excessive time overhead, whereas hardware methods require no time overhead but are unable to handle transmission delays in clock signals. The effects of nonzero transmission delays in synchronization have been studied extensively in the communication area in the absence of malicious or Byzantine faults. The authors show that it is easy to incorporate the ideas from the communication area into the existing hardware clock synchronization algorithms to take into account the presence of both malicious faults and nonzero transmission delays.

Intersection signal control multi-objective optimization based on genetic algorithm

OpenAIRE

Zhanhong Zhou; Ming Cai

2014-01-01

A signal control intersection increases not only vehicle delay, but also vehicle emissions and fuel consumption in that area. Because more and more fuel and air pollution problems arise recently, an intersection signal control optimization method which aims at reducing vehicle emissions, fuel consumption and vehicle delay is required heavily. This paper proposed a signal control multi-object optimization method to reduce vehicle emissions, fuel consumption and vehicle delay simultaneously at ...

Contrasting Regulation of NO and ROS in Potato Defense-Associated Metabolism in Response to Pathogens of Different Lifestyles.

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Jolanta Floryszak-Wieczorek

Full Text Available Our research provides new insights into how the low and steady-state levels of nitric oxide (NO and reactive oxygen species (ROS in potato leaves are altered after the challenge with the hemibiotroph Phytophthora infestans or the necrotroph Botrytis cinerea, with the subsequent rapid and invader-dependent modification of defense responses with opposite effects. Mainly in the avirulent (avr P. infestans-potato system, NO well balanced with the superoxide level was tuned with a battery of SA-dependent defense genes, leading to the establishment of the hypersensitive response (HR successfully arresting the pathogen. Relatively high levels of S-nitrosoglutathione and S-nitrosothiols concentrated in the main vein of potato leaves indicated the mobile function of these compounds as a reservoir of NO bioactivity. In contrast, low-level production of NO and ROS during virulent (vr P. infestans-potato interactions might be crucial in the delayed up-regulation of PR-1 and PR-3 genes and compromised resistance to the hemibiotrophic pathogen. In turn, B. cinerea triggered huge NO overproduction and governed inhibition of superoxide production by blunting NADPH oxidase. Nevertheless, a relatively high level of H2O2 was found owing to the germin-like activity in cooperation with NO-mediated HR-like cell death in potato genotypes favorable to the necrotrophic pathogen. Moreover, B. cinerea not only provoked cell death, but also modulated the host redox milieu by boosting protein nitration, which attenuated SA production but not SA-dependent defense gene expression. Finally, based on obtained data the organismal cost of having machinery for HR in plant resistance to biotrophs is also discussed, while emphasizing new efforts to identify other components of the NO/ROS cell death pathway and improve plant protection against pathogens of different lifestyles.

Ebselen induces reactive oxygen species (ROS-mediated cytotoxicity in Saccharomyces cerevisiae with inhibition of glutamate dehydrogenase being a target

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Gajendra Kumar Azad

2014-01-01

Full Text Available Ebselen is a synthetic, lipid-soluble seleno-organic compound. The high electrophilicity of ebselen enables it to react with multiple cysteine residues of various proteins. Despite extensive research on ebselen, its target molecules and mechanism of action remains less understood. We performed biochemical as well as in vivo experiments employing budding yeast as a model organism to understand the mode of action of ebselen. The growth curve analysis and FACS (florescence activated cell sorting assays revealed that ebselen exerts growth inhibitory effects on yeast cells by causing a delay in cell cycle progression. We observed that ebselen exposure causes an increase in intracellular ROS levels and mitochondrial membrane potential, and that these effects were reversed by addition of antioxidants such as reduced glutathione (GSH or N-acetyl-l-cysteine (NAC. Interestingly, a significant increase in ROS levels was noticed in gdh3-deleted cells compared to wild-type cells. Furthermore, we showed that ebselen inhibits GDH function by interacting with its cysteine residues, leading to the formation of inactive hexameric GDH. Two-dimensional gel electrophoresis revealed protein targets of ebselen including CPR1, the yeast homolog of Cyclophilin A. Additionally, ebselen treatment leads to the inhibition of yeast sporulation. These results indicate a novel direct connection between ebselen and redox homeostasis.

Ebselen induces reactive oxygen species (ROS)-mediated cytotoxicity in Saccharomyces cerevisiae with inhibition of glutamate dehydrogenase being a target.

Science.gov (United States)

Azad, Gajendra Kumar; Singh, Vikash; Mandal, Papita; Singh, Prabhat; Golla, Upendarrao; Baranwal, Shivani; Chauhan, Sakshi; Tomar, Raghuvir S

2014-01-01

Ebselen is a synthetic, lipid-soluble seleno-organic compound. The high electrophilicity of ebselen enables it to react with multiple cysteine residues of various proteins. Despite extensive research on ebselen, its target molecules and mechanism of action remains less understood. We performed biochemical as well as in vivo experiments employing budding yeast as a model organism to understand the mode of action of ebselen. The growth curve analysis and FACS (florescence activated cell sorting) assays revealed that ebselen exerts growth inhibitory effects on yeast cells by causing a delay in cell cycle progression. We observed that ebselen exposure causes an increase in intracellular ROS levels and mitochondrial membrane potential, and that these effects were reversed by addition of antioxidants such as reduced glutathione (GSH) or N-acetyl-l-cysteine (NAC). Interestingly, a significant increase in ROS levels was noticed in gdh3-deleted cells compared to wild-type cells. Furthermore, we showed that ebselen inhibits GDH function by interacting with its cysteine residues, leading to the formation of inactive hexameric GDH. Two-dimensional gel electrophoresis revealed protein targets of ebselen including CPR1, the yeast homolog of Cyclophilin A. Additionally, ebselen treatment leads to the inhibition of yeast sporulation. These results indicate a novel direct connection between ebselen and redox homeostasis.

Caffeine Induces Cell Death via Activation of Apoptotic Signal and Inactivation of Survival Signal in Human Osteoblasts

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Wen-Hsiung Chan

2008-05-01

Full Text Available Caffeine consumption is a risk factor for osteoporosis, but the precise regulatory mechanisms are currently unknown. Here, we show that cell viability decreases in osteoblasts treated with caffeine in a dose-dependent manner. This cell death is attributed primarily to apoptosis and to a smaller extent, necrosis. Moreover, caffeine directly stimulates intracellular oxidative stress. Our data support caffeine-induced apoptosis in osteoblasts via a mitochondria-dependent pathway. The apoptotic biochemical changes were effectively prevented upon pretreatment with ROS scavengers, indicating that ROS plays a critical role as an upstream controller in the caffeine-induced apoptotic cascade. Additionally, p21-activated protein kinase 2 (PAK2 and c-Jun N-terminal kinase (JNK were activated in caffeine-treated osteoblasts. Experiments further found that PAK2 activity is required for caffeine-induced JNK activation and apoptosis. Importantly, our data also show that caffeine triggers cell death via inactivation of the survival signal, including the ERK- and Akt-mediated anti-apoptotic pathways. Finally, exposure of rats to dietary water containing 10~20 μM caffeine led to bone mineral density loss. These results demonstrate for the first time that caffeine triggers apoptosis in osteoblasts via activation of mitochondria-dependent cell death signaling and inactivation of the survival signal, and causes bone mineral density loss in vivo.

Artemisinin induces ROS-mediated caspase3 activation in ASTC-a-1 cells

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Xiao, Feng-Lian; Chen, Tong-Sheng; Qu, Jun-Le; Liu, Cheng-Yi

2010-02-01

Artemisinin (ART), an antimalarial phytochemical from the sweet wormwood plant or a naturally occurring component of Artemisia annua, has been shown a potential anticancer activity by apoptotic pathways. In our report, cell counting kit (CCK-8) assay showed that treatment of human lung adenocarcinoma (ASTC-a-1) cells with ART effectively increase cell death by inducing apoptosis in a time- and dose-dependent fashion. Hoechst 33258 staining was used to detect apoptosis as well. Reactive oxygen species (ROS) generation was observed in cells exposed to ART at concentrations of 400 μM for 48 h. N-acetyl-L-cysteine (NAC), an oxygen radical scavenger, suppressed the rate of ROS generation and inhibited the ART-induced apoptosis. Moreover, AFC assay (Fluorometric assay for Caspase3 activity) showed that ROS was involved in ART-induced caspase3 acitvation. Taken together, our data indicate that ART induces ROS-mediated caspase3 activation in a time-and dose-dependent way in ASCT-a-1 cells.

All-optical delay technique for supporting multiple antennas in a hybrid optical - wireless transmission system

DEFF Research Database (Denmark)

Prince, Kamau; Chiuchiarelli, A; Presi, M

2008-01-01

We introduce a novel continuously-variable optical delay technique to support beam-forming wireless communications systems using antenna arrays. We demonstrate delay with 64-QAM modulated signals at a rate of 15 Msymbol/sec with 2.5 GHz carrier frequency.......We introduce a novel continuously-variable optical delay technique to support beam-forming wireless communications systems using antenna arrays. We demonstrate delay with 64-QAM modulated signals at a rate of 15 Msymbol/sec with 2.5 GHz carrier frequency....

Particulate matter exposure exacerbates high glucose-induced cardiomyocyte dysfunction through ROS generation.

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Li Zuo

Full Text Available Diabetes mellitus and fine particulate matter from diesel exhaust (DEP are both important contributors to the development of cardiovascular disease (CVD. Diabetes mellitus is a progressive disease with a high mortality rate in patients suffering from CVD, resulting in diabetic cardiomyopathy. Elevated DEP levels in the air are attributed to the development of various CVDs, presumably since fine DEP (<2.5 µm in diameter can be inhaled and gain access to the circulatory system. However, mechanisms defining how DEP affects diabetic or control cardiomyocyte function remain poorly understood. The purpose of the present study was to evaluate cardiomyocyte function and reactive oxygen species (ROS generation in isolated rat ventricular myocytes exposed overnight to fine DEP (0.1 µg/ml, and/or high glucose (HG, 25.5 mM. Our hypothesis was that DEP exposure exacerbates contractile dysfunction via ROS generation in cardiomyocytes exposed to HG. Ventricular myocytes were isolated from male adult Sprague-Dawley rats cultured overnight and sarcomeric contractile properties were evaluated, including: peak shortening normalized to baseline (PS, time-to-90% shortening (TPS(90, time-to-90% relengthening (TR(90 and maximal velocities of shortening/relengthening (±dL/dt, using an IonOptix field-stimulator system. ROS generation was determined using hydroethidine/ethidium confocal microscopy. We found that DEP exposure significantly increased TR(90, decreased PS and ±dL/dt, and enhanced intracellular ROS generation in myocytes exposed to HG. Further studies indicated that co-culture with antioxidants (0.25 mM Tiron and 0.5 mM N-Acetyl-L-cysteine completely restored contractile function in DEP, HG and HG+DEP-treated myocytes. ROS generation was blocked in HG-treated cells with mitochondrial inhibition, while ROS generation was blocked in DEP-treated cells with NADPH oxidase inhibition. Our results suggest that DEP exacerbates myocardial dysfunction in isolated

Unfolded protein response (UPR) signaling regulates arsenic trioxide-mediated macrophage innate immune function disruption

International Nuclear Information System (INIS)

Srivastava, Ritesh K.; Li, Changzhao; Chaudhary, Sandeep C.; Ballestas, Mary E.; Elmets, Craig A.; Robbins, David J.; Matalon, Sadis; Deshane, Jessy S.; Afaq, Farrukh; Bickers, David R.; Athar, Mohammad

2013-01-01

Arsenic exposure is known to disrupt innate immune functions in humans and in experimental animals. In this study, we provide a mechanism by which arsenic trioxide (ATO) disrupts macrophage functions. ATO treatment of murine macrophage cells diminished internalization of FITC-labeled latex beads, impaired clearance of phagocytosed fluorescent bacteria and reduced secretion of pro-inflammatory cytokines. These impairments in macrophage functions are associated with ATO-induced unfolded protein response (UPR) signaling pathway characterized by the enhancement in proteins such as GRP78, p-PERK, p-eIF2α, ATF4 and CHOP. The expression of these proteins is altered both at transcriptional and translational levels. Pretreatment with chemical chaperon, 4-phenylbutyric acid (PBA) attenuated the ATO-induced activation in UPR signaling and afforded protection against ATO-induced disruption of macrophage functions. This treatment also reduced ATO-mediated reactive oxygen species (ROS) generation. Interestingly, treatment with antioxidant N-acetylcysteine (NAC) prior to ATO exposure, not only reduced ROS production and UPR signaling but also improved macrophage functions. These data demonstrate that UPR signaling and ROS generation are interdependent and are involved in the arsenic-induced pathobiology of macrophage. These data also provide a novel strategy to block the ATO-dependent impairment in innate immune responses. - Highlights: • Inorganic arsenic to humans and experimental animals disrupt innate immune responses. • The mechanism underlying arsenic impaired macrophage functions involves UPR signaling. • Chemical chaperon attenuates arsenic-mediated macrophage function impairment. • Antioxidant, NAC blocks impairment in arsenic-treated macrophage functions

Unfolded protein response (UPR) signaling regulates arsenic trioxide-mediated macrophage innate immune function disruption

Energy Technology Data Exchange (ETDEWEB)

Srivastava, Ritesh K.; Li, Changzhao; Chaudhary, Sandeep C. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Ballestas, Mary E. [Department of Pediatrics Infectious Disease, Children' s of Alabama, School of Medicine, University of Alabama at Birmingham, AL (United States); Elmets, Craig A. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Robbins, David J. [Department of Surgery, Molecular Oncology Program, Miller School of Medicine, University of Miami, Miami (United States); Matalon, Sadis [Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL (United States); Deshane, Jessy S. [Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL (United States); Afaq, Farrukh [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Bickers, David R. [Department of Dermatology, Columbia University Medical Center, New York (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States)

2013-11-01

Arsenic exposure is known to disrupt innate immune functions in humans and in experimental animals. In this study, we provide a mechanism by which arsenic trioxide (ATO) disrupts macrophage functions. ATO treatment of murine macrophage cells diminished internalization of FITC-labeled latex beads, impaired clearance of phagocytosed fluorescent bacteria and reduced secretion of pro-inflammatory cytokines. These impairments in macrophage functions are associated with ATO-induced unfolded protein response (UPR) signaling pathway characterized by the enhancement in proteins such as GRP78, p-PERK, p-eIF2α, ATF4 and CHOP. The expression of these proteins is altered both at transcriptional and translational levels. Pretreatment with chemical chaperon, 4-phenylbutyric acid (PBA) attenuated the ATO-induced activation in UPR signaling and afforded protection against ATO-induced disruption of macrophage functions. This treatment also reduced ATO-mediated reactive oxygen species (ROS) generation. Interestingly, treatment with antioxidant N-acetylcysteine (NAC) prior to ATO exposure, not only reduced ROS production and UPR signaling but also improved macrophage functions. These data demonstrate that UPR signaling and ROS generation are interdependent and are involved in the arsenic-induced pathobiology of macrophage. These data also provide a novel strategy to block the ATO-dependent impairment in innate immune responses. - Highlights: • Inorganic arsenic to humans and experimental animals disrupt innate immune responses. • The mechanism underlying arsenic impaired macrophage functions involves UPR signaling. • Chemical chaperon attenuates arsenic-mediated macrophage function impairment. • Antioxidant, NAC blocks impairment in arsenic-treated macrophage functions.

The endogenous nitric oxide mediates selenium-induced phytotoxicity by promoting ROS generation in Brassica rapa.

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Yi Chen

Full Text Available Selenium (Se is suggested as an emerging pollutant in agricultural environment because of the increasing anthropogenic release of Se, which in turn results in phytotoxicity. The most common consequence of Se-induced toxicity in plants is oxidative injury, but how Se induces reactive oxygen species (ROS burst remains unclear. In this work, histofluorescent staining was applied to monitor the dynamics of ROS and nitric oxide (NO in the root of Brassica rapa under Se(IV stress. Se(IV-induced faster accumulation of NO than ROS. Both NO and ROS accumulation were positively correlated with Se(IV-induced inhibition of root growth. The NO accumulation was nitrate reductase (NR- and nitric oxide synthase (NOS-dependent while ROS accumulation was NADPH oxidase-dependent. The removal of NO by NR inhibitor, NOS inhibitor, and NO scavenger could alleviate Se(IV-induced expression of Br_Rbohs coding for NADPH oxidase and the following ROS accumulation in roots, which further resulted in the amelioration of Se(IV-induced oxidative injury and growth inhibition. Thus, we proposed that the endogenous NO played a toxic role in B. rapa under Se(IV stress by triggering ROS burst. Such findings can be used to evaluate the toxic effects of Se contamination on crop plants.

Hydroxychavicol, a betel leaf component, inhibits prostate cancer through ROS-driven DNA damage and apoptosis

Energy Technology Data Exchange (ETDEWEB)

Gundala, Sushma Reddy; Yang, Chunhua [Department of Biology, Georgia State University, Atlanta, GA 30303 (United States); Mukkavilli, Rao [Advinus Therapeutics, Karnataka (India); Paranjpe, Rutugandha; Brahmbhatt, Meera; Pannu, Vaishali; Cheng, Alice [Department of Biology, Georgia State University, Atlanta, GA 30303 (United States); Reid, Michelle D. [Department of Pathology, Emory University School of Medicine, Atlanta, GA (United States); Aneja, Ritu, E-mail: raneja@gsu.edu [Department of Biology, Georgia State University, Atlanta, GA 30303 (United States)

2014-10-01

Dietary phytochemicals are excellent ROS-modulating agents and have been shown to effectively enhance ROS levels beyond toxic threshold in cancer cells to ensure their selective killing while leaving normal cells unscathed. Here we demonstrate that hydroxychavicol (HC), extracted and purified from Piper betel leaves, significantly inhibits growth and proliferation via ROS generation in human prostate cancer, PC-3 cells. HC perturbed cell-cycle kinetics and progression, reduced clonogenicity and mediated cytotoxicity by ROS-induced DNA damage leading to activation of several pro-apoptotic molecules. In addition, HC treatment elicited a novel autophagic response as evidenced by the appearance of acidic vesicular organelles and increased expression of autophagic markers, LC3-IIb and beclin-1. Interestingly, quenching of ROS with tiron, an antioxidant, offered significant protection against HC-induced inhibition of cell growth and down regulation of caspase-3, suggesting the crucial role of ROS in mediating cell death. The collapse of mitochondrial transmembrane potential by HC further revealed the link between ROS generation and induction of caspase-mediated apoptosis in PC-3 cells. Our data showed remarkable inhibition of prostate tumor xenografts by ∼ 72% upon daily oral administration of 150 mg/kg bw HC by quantitative tumor volume measurements and non-invasive real-time bioluminescent imaging. HC was well-tolerated at this dosing level without any observable toxicity. This is the first report to demonstrate the anti-prostate cancer efficacy of HC in vitro and in vivo, which is perhaps attributable to its selective prooxidant activity to eliminate cancer cells thus providing compelling grounds for future preclinical studies to validate its potential usefulness for prostate cancer management. - Highlights: • HC perturbs cell-cycle progression by induction of reactive oxygen species (ROS). • HC mediated cytotoxicity by ROS-induced DNA damage leading to

Hydroxychavicol, a betel leaf component, inhibits prostate cancer through ROS-driven DNA damage and apoptosis

International Nuclear Information System (INIS)

Gundala, Sushma Reddy; Yang, Chunhua; Mukkavilli, Rao; Paranjpe, Rutugandha; Brahmbhatt, Meera; Pannu, Vaishali; Cheng, Alice; Reid, Michelle D.; Aneja, Ritu

2014-01-01

Dietary phytochemicals are excellent ROS-modulating agents and have been shown to effectively enhance ROS levels beyond toxic threshold in cancer cells to ensure their selective killing while leaving normal cells unscathed. Here we demonstrate that hydroxychavicol (HC), extracted and purified from Piper betel leaves, significantly inhibits growth and proliferation via ROS generation in human prostate cancer, PC-3 cells. HC perturbed cell-cycle kinetics and progression, reduced clonogenicity and mediated cytotoxicity by ROS-induced DNA damage leading to activation of several pro-apoptotic molecules. In addition, HC treatment elicited a novel autophagic response as evidenced by the appearance of acidic vesicular organelles and increased expression of autophagic markers, LC3-IIb and beclin-1. Interestingly, quenching of ROS with tiron, an antioxidant, offered significant protection against HC-induced inhibition of cell growth and down regulation of caspase-3, suggesting the crucial role of ROS in mediating cell death. The collapse of mitochondrial transmembrane potential by HC further revealed the link between ROS generation and induction of caspase-mediated apoptosis in PC-3 cells. Our data showed remarkable inhibition of prostate tumor xenografts by ∼ 72% upon daily oral administration of 150 mg/kg bw HC by quantitative tumor volume measurements and non-invasive real-time bioluminescent imaging. HC was well-tolerated at this dosing level without any observable toxicity. This is the first report to demonstrate the anti-prostate cancer efficacy of HC in vitro and in vivo, which is perhaps attributable to its selective prooxidant activity to eliminate cancer cells thus providing compelling grounds for future preclinical studies to validate its potential usefulness for prostate cancer management. - Highlights: • HC perturbs cell-cycle progression by induction of reactive oxygen species (ROS). • HC mediated cytotoxicity by ROS-induced DNA damage leading to

Loss of Intralipid®- but not sevoflurane-mediated cardioprotection in early type-2 diabetic hearts of fructose-fed rats: importance of ROS signaling.

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Phing-How Lou

Full Text Available Insulin resistance and early type-2 diabetes are highly prevalent. However, it is unknown whether Intralipid® and sevoflurane protect the early diabetic heart against ischemia-reperfusion injury.Early type-2 diabetic hearts from Sprague-Dawley rats fed for 6 weeks with fructose were exposed to 15 min of ischemia and 30 min of reperfusion. Intralipid® (1% was administered at the onset of reperfusion. Peri-ischemic sevoflurane (2 vol.-% served as alternative protection strategy. Recovery of left ventricular function was recorded and the activation of Akt and ERK 1/2 was monitored. Mitochondrial function was assessed by high-resolution respirometry and mitochondrial ROS production was measured by Amplex Red and aconitase activity assays. Acylcarnitine tissue content was measured and concentration-response curves of complex IV inhibition by palmitoylcarnitine were obtained.Intralipid® did not exert protection in early diabetic hearts, while sevoflurane improved functional recovery. Sevoflurane protection was abolished by concomitant administration of the ROS scavenger N-2-mercaptopropionyl glycine. Sevoflurane, but not Intralipid® produced protective ROS during reperfusion, which activated Akt. Intralipid® failed to inhibit respiratory complex IV, while sevoflurane inhibited complex I. Early diabetic hearts exhibited reduced carnitine-palmitoyl-transferase-1 activity, but palmitoylcarnitine could not rescue protection and enhance postischemic functional recovery. Cardiac mitochondria from early diabetic rats exhibited an increased content of subunit IV-2 of respiratory complex IV and of uncoupling protein-3.Early type-2 diabetic hearts lose complex IV-mediated protection by Intralipid® potentially due to a switch in complex IV subunit expression and increased mitochondrial uncoupling, but are amenable to complex I-mediated sevoflurane protection.

Effects of Camphorquinone on Cytotoxicity, Cell Cycle Regulation and Prostaglandin E2 Production of Dental Pulp Cells: Role of ROS, ATM/Chk2, MEK/ERK and Hemeoxygenase-1.

Directory of Open Access Journals (Sweden)

Mei-Chi Chang

Full Text Available Camphorquinone (CQ is a popularly-used photosensitizer in composite resin restoration. In this study, the effects of CQ on cytotoxicity and inflammation-related genes and proteins expression of pulp cells were investigated. The role of reactive oxygen species (ROS, ATM/Chk2/p53 and hemeoxygenase-1 (HO-1 and MEK/ERK signaling was also evaluated. We found that ROS and free radicals may play important role in CQ toxicity. CQ (1 and 2 mM decreased the viability of pulp cells to about 70% and 50% of control, respectively. CQ also induced G2/M cell cycle arrest and apoptosis of pulp cells. The expression of type I collagen, cdc2, cyclin B, and cdc25C was inhibited, while p21, HO-1 and cyclooxygenase-2 (COX-2 were stimulated by CQ. CQ also activated ATM, Chk2, and p53 phosphorylation and GADD45α expression. Besides, exposure to CQ increased cellular ROS level and 8-isoprostane production. CQ also stimulated COX-2 expression and PGE2 production of pulp cells. The reduction of cell viability caused by CQ can be attenuated by N-acetyl-L-cysteine (NAC, catalase and superoxide dismutase (SOD, but can be promoted by Zinc protoporphyin (ZnPP. CQ stimulated ERK1/2 phosphorylation, and U0126 prevented the CQ-induced COX-2 expression and prostaglandin E2 (PGE2 production. These results indicate that CQ may cause cytotoxicity, cell cycle arrest, apoptosis, and PGE2 production of pulp cells. These events could be due to stimulation of ROS and 8-isoprostane production, ATM/Chk2/p53 signaling, HO-1, COX-2 and p21 expression, as well as the inhibition of cdc2, cdc25C and cyclin B1. These results are important for understanding the role of ROS in pathogenesis of pulp necrosis and pulpal inflammation after clinical composite resin filling.

Nickel (II)-induced cytotoxicity and apoptosis in human proximal tubule cells through a ROS- and mitochondria-mediated pathway

Energy Technology Data Exchange (ETDEWEB)

Wang, Yi-Fen; Shyu, Huey-Wen [Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan (China); Chang, Yi-Chuang [Department of Nursing, Fooyin University, Kaohsiung, Taiwan (China); Tseng, Wei-Chang [Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan (China); Huang, Yeou-Lih [Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Lin, Kuan-Hua; Chou, Miao-Chen; Liu, Heng-Ling [Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan (China); Chen, Chang-Yu, E-mail: mt037@mail.fy.edu.tw [Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan (China)

2012-03-01

Nickel compounds are known to be toxic and carcinogenic in kidney and lung. In this present study, we investigated the roles of reactive oxygen species (ROS) and mitochondria in nickel (II) acetate-induced cytotoxicity and apoptosis in the HK-2 human renal cell line. The results showed that the cytotoxic effects of nickel (II) involved significant cell death and DNA damage. Nickel (II) increased the generation of ROS and induced a noticeable reduction of mitochondrial membrane potential (MMP). Analysis of the sub-G1 phase showed a significant increase in apoptosis in HK-2 cells after nickel (II) treatment. Pretreatment with N-acetylcysteine (NAC) not only inhibited nickel (II)-induced cell death and DNA damage, but also significantly prevented nickel (II)-induced loss of MMP and apoptosis. Cell apoptosis triggered by nickel (II) was characterized by the reduced protein expression of Bcl-2 and Bcl-xL and the induced the protein expression of Bad, Bcl-Xs, Bax, cytochrome c and caspases 9, 3 and 6. The regulation of the expression of Bcl-2-family proteins, the release of cytochrome c and the activation of caspases 9, 3 and 6 were inhibited in the presence of NAC. These results suggest that nickel (II) induces cytotoxicity and apoptosis in HK-2 cells via ROS generation and that the mitochondria-mediated apoptotic signaling pathway may be involved in the positive regulation of nickel (II)-induced renal cytotoxicity.

Nickel (II)-induced cytotoxicity and apoptosis in human proximal tubule cells through a ROS- and mitochondria-mediated pathway

International Nuclear Information System (INIS)

Wang, Yi-Fen; Shyu, Huey-Wen; Chang, Yi-Chuang; Tseng, Wei-Chang; Huang, Yeou-Lih; Lin, Kuan-Hua; Chou, Miao-Chen; Liu, Heng-Ling; Chen, Chang-Yu

2012-01-01

Nickel compounds are known to be toxic and carcinogenic in kidney and lung. In this present study, we investigated the roles of reactive oxygen species (ROS) and mitochondria in nickel (II) acetate-induced cytotoxicity and apoptosis in the HK-2 human renal cell line. The results showed that the cytotoxic effects of nickel (II) involved significant cell death and DNA damage. Nickel (II) increased the generation of ROS and induced a noticeable reduction of mitochondrial membrane potential (MMP). Analysis of the sub-G1 phase showed a significant increase in apoptosis in HK-2 cells after nickel (II) treatment. Pretreatment with N-acetylcysteine (NAC) not only inhibited nickel (II)-induced cell death and DNA damage, but also significantly prevented nickel (II)-induced loss of MMP and apoptosis. Cell apoptosis triggered by nickel (II) was characterized by the reduced protein expression of Bcl-2 and Bcl-xL and the induced the protein expression of Bad, Bcl-Xs, Bax, cytochrome c and caspases 9, 3 and 6. The regulation of the expression of Bcl-2-family proteins, the release of cytochrome c and the activation of caspases 9, 3 and 6 were inhibited in the presence of NAC. These results suggest that nickel (II) induces cytotoxicity and apoptosis in HK-2 cells via ROS generation and that the mitochondria-mediated apoptotic signaling pathway may be involved in the positive regulation of nickel (II)-induced renal cytotoxicity.

Dynamics of microbubble oscillators with delay coupling

Science.gov (United States)

Heckman, C. R.; Sah, S. M.; Rand, R. H.

2010-10-01

We investigate the stability of the in-phase mode in a system of two delay-coupled bubble oscillators. The bubble oscillator model is based on a 1956 paper by Keller and Kolodner. Delay coupling is due to the time it takes for a signal to travel from one bubble to another through the liquid medium that surrounds them. Using techniques from the theory of differential-delay equations as well as perturbation theory, we show that the equilibrium of the in-phase mode can be made unstable if the delay is long enough and if the coupling strength is large enough, resulting in a Hopf bifurcation. We then employ Lindstedt's method to compute the amplitude of the limit cycle as a function of the time delay. This work is motivated by medical applications involving noninvasive localized drug delivery via microbubbles.

Upregulation of NOX2 and NOX4 Mediated by TGF-β Signaling Pathway Exacerbates Cerebral Ischemia/Reperfusion Oxidative Stress Injury

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Zheng Lou

2018-04-01

Full Text Available Background/Aims: Ischemic stroke is still one of the leading debilitating diseases with high morbidity and mortality. NADPH oxidase (NOX-derived reactive oxygen species (ROS play an important role in cerebral ischemia/reperfusion (I/R injury. However, the mechanism underlying the regulation of ROS generation is still not fully elucidated. This study aims to explore the role of transforming growth beta (TGF-β signals in ROS generation. Methods: Sprague–Dawley rats were subjected to I/R injury, and PC-12 cells were challenged by hypoxia/reoxygenation (H/R and/or treated with activin receptor-like kinase (ALK5 inhibitor Sb505124 or siRNA against ALK5. Brain damage was evaluated using neurological scoring, triphenyl tetrazolium chloride staining, hematoxylin and eosin staining, infarct volume measurement, TUNEL staining, and caspase-3 activity measurement. Expression of TGF-β and oxidative stress-related genes was analyzed by real-time polymerase chain reaction and Western blot; NOX activity and ROS level were measured using spectrophotometry and fluorescence microscopy, respectively. Results: I/R contributed to severe brain damage (impaired neurological function, brain infarction, tissue edema, apoptosis, TGF-β signaling activation (upregulation of ALK5, phosphorylation of SMAD2/3 and oxidative stress (upregulation of NOX2/4, rapid release of ROS [oxidative burst]. However, Sb505124 significantly reversed these alterations and protected rats against I/R injury. As in the animal results, H/R also contributed to TGF-β signaling activation and oxidative stress. Likewise, the inhibition of ALK5 or ALK5 knockdown significantly reversed these alterations in PC-12 cells. Other than ALK5 knockdown, ALK5 inhibition had no effect on the expression of ALK5 in PC-12 cells. Conclusions: Our studies demonstrated that TGF-β signaling activation is involved in the regulation of NOX2/NOX4 expression and exacerbates cerebral I/R injury.

Cracking chaos-based encryption systems ruled by nonlinear time delay differential equations

International Nuclear Information System (INIS)

Udaltsov, Vladimir S.; Goedgebuer, Jean-Pierre; Larger, Laurent; Cuenot, Jean-Baptiste; Levy, Pascal; Rhodes, William T.

2003-01-01

We report that signal encoding with high-dimensional chaos produced by delayed feedback systems with a strong nonlinearity can be broken. We describe the procedure and illustrate the method with chaotic waveforms obtained from a strongly nonlinear optical system that we used previously to demonstrate signal encryption/decryption with chaos in wavelength. The method can be extended to any systems ruled by nonlinear time-delayed differential equations

Bearing fault detection utilizing group delay and the Hilbert-Huang transform

International Nuclear Information System (INIS)

Jin, Shuai; Lee, Sang-Kwon

2017-01-01

Vibration signals measured from a mechanical system are useful to detect system faults. Signal processing has been used to extract fault information in bearing systems. However, a wide vibration signal frequency band often affects the ability to obtain the effective fault features. In addition, a few oscillation components are not useful at the entire frequency band in a vibration signal. By contrast, useful fatigue information can be embedded in the noise oscillation components. Thus, a method to estimate which frequency band contains fault information utilizing group delay was proposed in this paper. Group delay as a measure of phase distortion can indicate the phase structure relationship in the frequency domain between original (with noise) and denoising signals. We used the empirical mode decomposition of a Hilbert-Huang transform to sift the useful intrinsic mode functions based on the results of group delay after determining the valuable frequency band. Finally, envelope analysis and the energy distribution after the Hilbert transform were used to complete the fault diagnosis. The practical bearing fault data, which were divided into inner and outer race faults, were used to verify the efficiency and quality of the proposed method

Bearing fault detection utilizing group delay and the Hilbert-Huang transform

Energy Technology Data Exchange (ETDEWEB)

Jin, Shuai; Lee, Sang-Kwon [Inha University, Incheon (Korea, Republic of)

2017-03-15

Vibration signals measured from a mechanical system are useful to detect system faults. Signal processing has been used to extract fault information in bearing systems. However, a wide vibration signal frequency band often affects the ability to obtain the effective fault features. In addition, a few oscillation components are not useful at the entire frequency band in a vibration signal. By contrast, useful fatigue information can be embedded in the noise oscillation components. Thus, a method to estimate which frequency band contains fault information utilizing group delay was proposed in this paper. Group delay as a measure of phase distortion can indicate the phase structure relationship in the frequency domain between original (with noise) and denoising signals. We used the empirical mode decomposition of a Hilbert-Huang transform to sift the useful intrinsic mode functions based on the results of group delay after determining the valuable frequency band. Finally, envelope analysis and the energy distribution after the Hilbert transform were used to complete the fault diagnosis. The practical bearing fault data, which were divided into inner and outer race faults, were used to verify the efficiency and quality of the proposed method.

Inositol 1,4,5-trisphosphate (IP3)-dependent Ca2+ signaling mediates delayed myogenesis in Duchenne muscular dystrophy fetal muscle.

Science.gov (United States)

Farini, Andrea; Sitzia, Clementina; Cassinelli, Letizia; Colleoni, Federica; Parolini, Daniele; Giovanella, Umberto; Maciotta, Simona; Colombo, Augusto; Meregalli, Mirella; Torrente, Yvan

2016-02-15

Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disorder characterized by muscle wasting and premature death. The defective gene is dystrophin, a structural protein, absence of which causes membrane fragility and myofiber necrosis. Several lines of evidence showed that in adult DMD patients dystrophin is involved in signaling pathways that regulate calcium homeostasis and differentiation programs. However, secondary aspects of the disease, such as inflammation and fibrosis development, might represent a bias in the analysis. Because fetal muscle is not influenced by gravity and does not suffer from mechanical load and/or inflammation, we investigated 12-week-old fetal DMD skeletal muscles, highlighting for the first time early alterations in signaling pathways mediated by the absence of dystrophin itself. We found that PLC/IP3/IP3R/Ryr1/Ca(2+) signaling is widely active in fetal DMD skeletal muscles and, through the calcium-dependent PKCα protein, exerts a fundamental regulatory role in delaying myogenesis and in myofiber commitment. These data provide new insights into the origin of DMD pathology during muscle development. © 2016. Published by The Company of Biologists Ltd.

UPP mediated Diabetic Retinopathy via ROS/PARP and NF-κB inflammatory factor pathways.

Science.gov (United States)

Luo, D-W; Zheng, Z; Wang, H; Fan, Y; Chen, F; Sun, Y; Wang, W-J; Sun, T; Xu, X

2015-01-01

Diabetic retinopathy (DR) is a leading cause of blindness in adults at working age. Human diabetic retinopathy is characterized by the basement membrane thick, pericytes loss, microaneurysms formation, retina neovascularization and vitreous hemorrhage. To investigate whether UPP activated ROS/PARP and NF-κB inflammatory factor pathways in Diabetic Retinopathy, human retinal endothelial cells (HRECs) and rats with streptozotocin-induced diabetes were used to determine the effect of UPP on ROS generation, cell apoptosis, mitochondrial membrane potential (ΔΨm) and inflammatory factor protein expression, through flow cytometry assay, immunohistochemistry, Real-time PCR, Western blot analysis and ELISA. The levels of ROS and apoptosis and the expressions of UPP (Ub and E3) and inflammatory factor protein were increased in high glucose-induced HRECs and retina of diabetic rats, while ΔΨm was decreased. The UPP inhibitor and UbshRNA could attenuate these effects through inhibiting the pathway of ROS/PARP and the expression of NF-κB inflammatory factors, and the increased UPP was a result of high glucose-induced increase of ROS generation and NF-κBp65 expression, accompanied with the decrease of ΔΨm. Clinical study showed the overexpression of UPP and detachment of epiretinal membranes in proliferative DR (PDR) patients. It has been indicated that the pathogenic effect of UPP on DR was involved in the increase of ROS generation and NF-κB expression, which associated with the ROS/PARP and NF-κB inflammatory factor pathways. Our study supports a new insight for further application of UPP inhibitor in DR treatment.

Role of Mitochondrial Reactive Oxygen Species in the Activation of Cellular Signals, Molecules, and Function

DEFF Research Database (Denmark)

Indo, Hiroko P.; Hawkins, Clare L; Nakanishi, Ikuo

2017-01-01

-κB) and GATA signaling pathways. We have also reviewed the effects of ROS on the activation of MMP and HIF. There is significant evidence to support the hypothesis that mitochondrial superoxide can initiate signaling pathways following transport into the cytosol. In this study, we provide evidence of TATA...

European contribution to the study of ROS

DEFF Research Database (Denmark)

Egea, Javier; Fabregat, Isabel; Frapart, Yves M

2017-01-01

The European Cooperation in Science and Technology (COST) provides an ideal framework to establish multi-disciplinary research networks. COST Action BM1203 (EU-ROS) represents a consortium of researchers from different disciplines who are dedicated to providing new insights and tools for better u...

Photonic-assisted time-interleaved ADC based on optical delay line

International Nuclear Information System (INIS)

Xu, Chen; Zheng, Shilie; Chen, Xinyi; Chi, Hao; Jin, Xiaofeng; Zhang, Xianmin

2016-01-01

An approach to implement photonic-assisted time-interleaved analog-to-digital conversion and its calibration method are presented. The analog modulated optical signal is divided into M channels, suffering different time delay induced by optical delay lines which provide great flexibility in producing time intervals and is then sampled by electronic analog-to-digital converters (ADCs). The channel mismatches resulting in performance degradation are estimated by a modified sine wave fitting method. The time mismatch and other mismatches are corrected by fine optical delay adjustment and digital processing, respectively. A four-channel photonic-assisted time-interleaved analog-to-digital converter (TIADC) system operating at 40 GSa s −1 was demonstrated experimentally. The photonic-assisted TIADC system was tested with a 6.31 GHz sine wave signal, exhibiting 40.3 dB signal-to-noise and distortion ratio (SINAD) and 57.6 dBc spurious-free dynamic range (SFDR). It is shown that the SINAD is dominated by the signal-to-noise ratio (SNR) of the analog optical link and the SFDR of the proposed system is limited by the linearity of the link. (paper)

A stochastic step model of replicative senescence explains ROS production rate in ageing cell populations.

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Conor Lawless

Full Text Available Increases in cellular Reactive Oxygen Species (ROS concentration with age have been observed repeatedly in mammalian tissues. Concomitant increases in the proportion of replicatively senescent cells in ageing mammalian tissues have also been observed. Populations of mitotic human fibroblasts cultured in vitro, undergoing transition from proliferation competence to replicative senescence are useful models of ageing human tissues. Similar exponential increases in ROS with age have been observed in this model system. Tracking individual cells in dividing populations is difficult, and so the vast majority of observations have been cross-sectional, at the population level, rather than longitudinal observations of individual cells.One possible explanation for these observations is an exponential increase in ROS in individual fibroblasts with time (e.g. resulting from a vicious cycle between cellular ROS and damage. However, we demonstrate an alternative, simple hypothesis, equally consistent with these observations which does not depend on any gradual increase in ROS concentration: the Stochastic Step Model of Replicative Senescence (SSMRS. We also demonstrate that, consistent with the SSMRS, neither proliferation-competent human fibroblasts of any age, nor populations of hTERT overexpressing human fibroblasts passaged beyond the Hayflick limit, display high ROS concentrations. We conclude that longitudinal studies of single cells and their lineages are now required for testing hypotheses about roles and mechanisms of ROS increase during replicative senescence.

A stochastic step model of replicative senescence explains ROS production rate in ageing cell populations.

Science.gov (United States)

Lawless, Conor; Jurk, Diana; Gillespie, Colin S; Shanley, Daryl; Saretzki, Gabriele; von Zglinicki, Thomas; Passos, João F

2012-01-01

Increases in cellular Reactive Oxygen Species (ROS) concentration with age have been observed repeatedly in mammalian tissues. Concomitant increases in the proportion of replicatively senescent cells in ageing mammalian tissues have also been observed. Populations of mitotic human fibroblasts cultured in vitro, undergoing transition from proliferation competence to replicative senescence are useful models of ageing human tissues. Similar exponential increases in ROS with age have been observed in this model system. Tracking individual cells in dividing populations is difficult, and so the vast majority of observations have been cross-sectional, at the population level, rather than longitudinal observations of individual cells.One possible explanation for these observations is an exponential increase in ROS in individual fibroblasts with time (e.g. resulting from a vicious cycle between cellular ROS and damage). However, we demonstrate an alternative, simple hypothesis, equally consistent with these observations which does not depend on any gradual increase in ROS concentration: the Stochastic Step Model of Replicative Senescence (SSMRS). We also demonstrate that, consistent with the SSMRS, neither proliferation-competent human fibroblasts of any age, nor populations of hTERT overexpressing human fibroblasts passaged beyond the Hayflick limit, display high ROS concentrations. We conclude that longitudinal studies of single cells and their lineages are now required for testing hypotheses about roles and mechanisms of ROS increase during replicative senescence.

The Affordance Template ROS Package for Robot Task Programming

Science.gov (United States)

Hart, Stephen; Dinh, Paul; Hambuchen, Kimberly

2015-01-01

This paper introduces the Affordance Template ROS package for quickly programming, adjusting, and executing robot applications in the ROS RViz environment. This package extends the capabilities of RViz interactive markers by allowing an operator to specify multiple end-effector waypoint locations and grasp poses in object-centric coordinate frames and to adjust these waypoints in order to meet the run-time demands of the task (specifically, object scale and location). The Affordance Template package stores task specifications in a robot-agnostic XML description format such that it is trivial to apply a template to a new robot. As such, the Affordance Template package provides a robot-generic ROS tool appropriate for building semi-autonomous, manipulation-based applications. Affordance Templates were developed by the NASA-JSC DARPA Robotics Challenge (DRC) team and have since successfully been deployed on multiple platforms including the NASA Valkyrie and Robonaut 2 humanoids, the University of Texas Dreamer robot and the Willow Garage PR2. In this paper, the specification and implementation of the affordance template package is introduced and demonstrated through examples for wheel (valve) turning, pick-and-place, and drill grasping, evincing its utility and flexibility for a wide variety of robot applications.

Tunable Optical True-Time Delay Devices Would Exploit EIT

Science.gov (United States)

Kulikov, Igor; DiDomenico, Leo; Lee, Hwang

2004-01-01

Tunable optical true-time delay devices that would exploit electromagnetically induced transparency (EIT) have been proposed. Relative to prior true-time delay devices (for example, devices based on ferroelectric and ferromagnetic materials) and electronically controlled phase shifters, the proposed devices would offer much greater bandwidths. In a typical envisioned application, an optical pulse would be modulated with an ultra-wideband radio-frequency (RF) signal that would convey the information that one seeks to communicate, and it would be required to couple differently delayed replicas of the RF signal to the radiating elements of a phased-array antenna. One or more of the proposed devices would be used to impose the delays and/or generate the delayed replicas of the RF-modulated optical pulse. The beam radiated or received by the antenna would be steered by use of a microprocessor-based control system that would adjust operational parameters of the devices to tune the delays to the required values. EIT is a nonlinear quantum optical interference effect that enables the propagation of light through an initially opaque medium. A suitable medium must have, among other properties, three quantum states (see Figure 1): an excited state (state 3), an upper ground state (state 2), and a lower ground state (state 1). These three states must form a closed system that exhibits no decays to other states in the presence of either or both of two laser beams: (1) a probe beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 1; and (2) a coupling beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 2. The probe beam is the one that is pulsed and modulated with an RF signal.

Measurement of time delay for a prospectively gated CT simulator

Directory of Open Access Journals (Sweden)

Goharian M

2010-01-01

Full Text Available For the management of mobile tumors, respiratory gating is the ideal option, both during imaging and during therapy. The major advantage of respiratory gating during imaging is that it is possible to create a single artifact-free CT data-set during a selected phase of the patient′s breathing cycle. The purpose of the present work is to present a simple technique to measure the time delay during acquisition of a prospectively gated CT. The time delay of a Philips Brilliance BigBore™ (Philips Medical Systems, Madison, WI scanner attached to a Varian Real-Time Position Management™ (RPM system (Varian Medical Systems, Palo Alto, CA was measured. Two methods were used to measure the CT time delay: using a motion phantom and using a recorded data file from the RPM system. In the first technique, a rotating wheel phantom was altered by placing two plastic balls on its axis and rim, respectively. For a desired gate, the relative positions of the balls were measured from the acquired CT data and converted into corresponding phases. Phase difference was calculated between the measured phases and the desired phases. Using period of motion, the phase difference was converted into time delay. The Varian RPM system provides an external breathing signal; it also records transistor-transistor logic (TTL ′X-Ray ON′ status signal from the CT scanner in a text file. The TTL ′X-Ray ON′ indicates the start of CT image acquisition. Thus, knowledge of the start time of CT acquisition, combined with the real-time phase and amplitude data from the external respiratory signal, provides time-stamping of all images in an axial CT scan. The TTL signal with time-stamp was used to calculate when (during the breathing cycle a slice was recorded. Using the two approaches, the time delay between the prospective gating signal and CT simulator has been determined to be 367 ± 40 ms. The delay requires corrections both at image acquisition and while setting gates for

Measurement of time delay for a prospectively gated CT simulator

International Nuclear Information System (INIS)

Goharian, M.; Khan, R.F.H.

2010-01-01

For the management of mobile tumors, respiratory gating is the ideal option, both during imaging and during therapy. The major advantage of respiratory gating during imaging is that it is possible to create a single artifact-free CT data-set during a selected phase of the patient's breathing cycle. The purpose of the present work is to present a simple technique to measure the time delay during acquisition of a prospectively gated CT. The time delay of a Philips Brilliance BigBore (Philips Medical Systems, Madison, WI) scanner attached to a Varian Real-Time Position Management (RPM) system (Varian Medical Systems, Palo Alto, CA) was measured. Two methods were used to measure the CT time delay: using a motion phantom and using a recorded data file from the RPM system. In the first technique, a rotating wheel phantom was altered by placing two plastic balls on its axis and rim, respectively. For a desired gate, the relative positions of the balls were measured from the acquired CT data and converted into corresponding phases. Phase difference was calculated between the measured phases and the desired phases. Using period of motion, the phase difference was converted into time delay. The Varian RPM system provides an external breathing signal; it also records transistor-transistor logic (TTL) 'X-Ray ON' status signal from the CT scanner in a text file. The TTL 'X-Ray ON' indicates the start of CT image acquisition. Thus, knowledge of the start time of CT acquisition, combined with the real-time phase and amplitude data from the external respiratory signal, provides time-stamping of all images in an axial CT scan. The TTL signal with time-stamp was used to calculate when (during the breathing cycle) a slice was recorded. Using the two approaches, the time delay between the prospective gating signal and CT simulator has been determined to be 367 ± 40 ms. The delay requires corrections both at image acquisition and while setting gates for the treatment delivery

Synchronization of time-delayed systems with chaotic modulation and cryptography

International Nuclear Information System (INIS)

Banerjee, Santo

2009-01-01

This paper presents a method of synchronization between two time-delayed systems where the delay times are modulated by a common chaotic signal of the driving system. The technique is well applied to two identical autonomous continuous-time-delayed systems with numerical simulations. Finally, a new method of encryption is generated for digital messages. This method is illustrated with two different encryption processes for text as well as picture messages.

Phase noise mitigation of QPSK signal utilizing phase-locked multiplexing of signal harmonics and amplitude saturation.

Science.gov (United States)

Mohajerin-Ariaei, Amirhossein; Ziyadi, Morteza; Chitgarha, Mohammad Reza; Almaiman, Ahmed; Cao, Yinwen; Shamee, Bishara; Yang, Jeng-Yuan; Akasaka, Youichi; Sekiya, Motoyoshi; Takasaka, Shigehiro; Sugizaki, Ryuichi; Touch, Joseph D; Tur, Moshe; Langrock, Carsten; Fejer, Martin M; Willner, Alan E

2015-07-15

We demonstrate an all-optical phase noise mitigation scheme based on the generation, delay, and coherent summation of higher order signal harmonics. The signal, its third-order harmonic, and their corresponding delayed variant conjugates create a staircase phase-transfer function that quantizes the phase of quadrature-phase-shift-keying (QPSK) signal to mitigate phase noise. The signal and the harmonics are automatically phase-locked multiplexed, avoiding the need for phase-based feedback loop and injection locking to maintain coherency. The residual phase noise converts to amplitude noise in the quantizer stage, which is suppressed by parametric amplification in the saturation regime. Phase noise reduction of ∼40% and OSNR-gain of ∼3  dB at BER 10(-3) are experimentally demonstrated for 20- and 30-Gbaud QPSK input signals.

Heterogeneity of time delays determines synchronization of coupled oscillators.

Science.gov (United States)

Petkoski, Spase; Spiegler, Andreas; Proix, Timothée; Aram, Parham; Temprado, Jean-Jacques; Jirsa, Viktor K

2016-07-01

Network couplings of oscillatory large-scale systems, such as the brain, have a space-time structure composed of connection strengths and signal transmission delays. We provide a theoretical framework, which allows treating the spatial distribution of time delays with regard to synchronization, by decomposing it into patterns and therefore reducing the stability analysis into the tractable problem of a finite set of delay-coupled differential equations. We analyze delay-structured networks of phase oscillators and we find that, depending on the heterogeneity of the delays, the oscillators group in phase-shifted, anti-phase, steady, and non-stationary clusters, and analytically compute their stability boundaries. These results find direct application in the study of brain oscillations.

Characterization of structure and coagulation behaviour of refractory organic substances (ROS) using small-angle neutron scattering (SANS), small-angle x-ray scattering (SAXS) and x-ray microscopy; Charakterisierung von Struktur und Koagulationsverhalten von Refraktaeren Organischen Saeuren (ROS) mit Hilfe von Neutronenkleinwinkelstreuung (SANS), Roentgenkleinwinkelstreuung (SAXS) und Roentgenmikroskopie

Energy Technology Data Exchange (ETDEWEB)

Pranzas, P.K. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

1999-07-01

In this work structure, coagulation and complexation behaviour of aquatic refractory organic substances (ROS) (humic and fulvic acids) were characterized. For this purpose a structural analytical system with the methods small-angle neutron scattering (SANS), small-angle x-ray scattering (SAXS) and X-ray microscopy with synchrotron radiation was developed and established. Size distributions of ROS of different origin were calculated from the scattering curves. Spherical ROS units were obtained, which coagulated by forming chainlike structures or disordered ROS agglomerates at higher concentrations. Additionally the average molecular weights of several ROS were calculated. Studies of the coagulation behaviour of ROS towards copper ions resulted in larger ROS-agglomerates besides the spherical ROS units. A linear relation between the addition of Cu{sup 2+} and the formation of the ROS-Cu{sup 2+}-agglomerates was found. With X-ray microscopy an extensive ROS-Cu{sup 2}-network structure could be registrated. For mercury and cadmium ions such coagulation interactions were not found. Investigations with X-ray microscopy of the coagulation behaviour of ROS towards the cationic surfactant DTB resulted in micel-like structures of equal size, which were spread throughout the solution. With increasing concentrations of DTB larger agglomerates up to network structures were obtained. (orig.) [German] In dieser Arbeit wurden Struktur, Koagulations- und Komplexierungsverhalten von aquatischen refraktaeren organischen Saeuren (ROS) (Humin- und Fulvinsaeuren) charakterisiert. Zu diesem Zweck wurde ein strukturanalytisches Gesamtsystem mit den Methoden Neutronenkleinwinkelstreuung (SANS), Roentgenkleinwinkelstreuung (SAXS) und Roentgenmikroskopie mit Synchrotronstrahlung entwickelt und etabliert. Fuer ROS unterschiedlicher Herkunft in Loesung wurden Groessenverteilungen aus den Streukurven berechnet. Es wurden kugelfoermige ROS-Einheiten gefunden, die bei hoeheren ROS

Detection of ROS1 Gene Rearrangement in Lung Adenocarcinoma: Comparison of IHC, FISH and Real-Time RT-PCR

OpenAIRE

Shan, Ling; Lian, Fang; Guo, Lei; Qiu, Tian; Ling, Yun; Ying, Jianming; Lin, Dongmei

2015-01-01

Aims To compare fluorescence in situ hybridization (FISH), immunohistochemistry (IHC) and quantitative real-time reverse transcription-PCR (qRT-PCR) assays for detection of ROS1 fusion in a large number of ROS1-positive lung adenocatcinoma (ADC) patients. Methods Using IHC analysis, sixty lung ADCs including 16 cases with ROS1 protein expression and 44 cases without ROS1 expression were selected for this study. The ROS1 fusion status was examined by FISH and qRT-PCR assay. Results Among 60 ca...

DspA/E contributes to apoplastic accumulation of ROS in nonhost A. thaliana

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Alban eLaunay

2016-04-01

Full Text Available The bacterium Erwinia amylovora is responsible for the fire blight disease of Maleae, which provokes necrotic symptoms on aerial parts. The pathogenicity of this bacterium in hosts relies on its type three-secretion system (T3SS, a molecular syringe that allows the bacterium to inject effectors into the plant cell. E. amylovora-triggered disease in host plants is associated with the T3SS-dependent production of reactive oxygen species (ROS, although ROS are generally associated with resistance in other pathosystems. We showed previously that E. amylovora can multiply transiently in the nonhost plant Arabidopsis thaliana and that a T3SS-dependent production of intracellular ROS occurs during this interaction. In the present work we characterize the localization and source of hydrogen peroxide accumulation following E. amylovora infection. Transmission electron microscope (TEM analysis of infected tissues showed that hydrogen peroxide accumulation occurs in the cytosol, plastids, peroxisomes, and mitochondria as well as in the apoplast. Furthermore, TEM analysis showed that an E. amylovora dspA/E-deficient strain does not induce hydrogen peroxide accumulation in the apoplast. Consistently, a transgenic line expressing DspA/E accumulated ROS in the apoplast. The NADPH oxidase-deficient rbohD mutant showed a very strong reduction in hydrogen peroxide accumulation in response to E. amylovora inoculation. However, we did not find an increase in bacterial titers of E. amylovora in the rbohD mutant and the rbohD mutation did not suppress the toxicity of DspA/E when introgressed into a DspA/E-expressing transgenic line. Co-inoculation of E. amylovora with cycloheximide (CHX, which we found previously to suppress callose deposition and allow strong multiplication of E. amylovora in A. thaliana leaves, led to a strong reduction of apoplastic ROS accumulation but did not affect intracellular ROS. Our data strongly suggest that apoplastic ROS accumulation is

ALA/LA ameliorates glucose toxicity on HK-2 cells by attenuating oxidative stress and apoptosis through the ROS/p38/TGF-β1 pathway.

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Jiang, Mingxia; Zhang, Haifen; Zhai, Lijie; Ye, Bianliang; Cheng, Yin; Zhai, Chengkai

2017-11-16

Growing evidence indicates that oxidative stress (OS) plays a pivotal role in Diabetic nephropathy (DN). In a previous study we demonstrated that ALA/LA protected HK-2 cells against high glucose-induced cytotoxicity. So we aimed to establish the glucose injury model of HK-2 cells and investigate the beneficial effects of ALA/LA on high glucose-induced excessive production of TGF-β1 and the possible mechanisms mediating the effects. The expression of OS markers in high glucose-induced HK-2 cells treated with ALA/LA., including the antioxidant enzymes and reactive oxygen species (ROS) production, as well as the apoptosis rate were assayed by ELISA and flow cytometry. The p38/transforming growth factor β 1 (TGF-β 1 ) signal pathway were measured by real-time RT-PCR and western blot. The modeling condition of glucose toxicity on HK-2 cells was at the glucose concentration of 40.9 mM. ALA/LA can significantly increase the activities of antioxidant enzymes and decrease ROS production stimulated by high glucose. The study also found that ALA/LA caused a decrease in the apoptosis rate and TGF-β 1 level of HK-2 cells under high glucose stress through the ROS/p38 pathway. ALA/LA exerts protective effects in vitro through inhibition of ROS generation, down regulation of the activation of the p38MAPK pathway and the expression of TGF-β 1 in HK-2 cells.

Targeting the ROS-HIF-1-endothelin axis as a therapeutic approach for the treatment of obstructive sleep apnea-related cardiovascular complications.

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Belaidi, Elise; Morand, Jessica; Gras, Emmanuelle; Pépin, Jean-Louis; Godin-Ribuot, Diane

2016-12-01

Obstructive sleep apnea (OSA) is now recognized as an independent and important risk factor for cardiovascular diseases such as hypertension, coronary heart disease, heart failure and stroke. Clinical and experimental data have confirmed that intermittent hypoxia is a major contributor to these deleterious consequences. The repetitive occurrence of hypoxia-reoxygenation sequences generates significant amounts of free radicals, particularly in moderate to severe OSA patients. Moreover, in addition to hypoxia, reactive oxygen species (ROS) are potential inducers of the hypoxia inducible transcription factor-1 (HIF-1) that promotes the transcription of numerous adaptive genes some of which being deleterious for the cardiovascular system, such as the endothelin-1 gene. This review will focus on the involvement of the ROS-HIF-1-endothelin signaling pathway in OSA and intermittent hypoxia and discuss current and potential therapeutic approaches targeting this pathway to treat or prevent cardiovascular disease in moderate to severe OSA patients. Copyright © 2016 Elsevier Inc. All rights reserved.

Targeting the ROS-HIF-1-endothelin axis as a therapeutic approach for the treatment of obstructive sleep apnea-related cardiovascular complications

Science.gov (United States)

Belaidi, Elise; Morand, Jessica; Gras, Emmanuelle; Pépin, Jean-Louis; Godin-Ribuot, Diane

2016-01-01

Obstructive sleep apnea (OSA) is now recognized as an independent and important risk factor for cardiovascular diseases such as hypertension, coronary heart disease, heart failure and stroke. Clinical and experimental data have confirmed that intermittent hypoxia is a major contributor to these deleterious consequences. The repetitive occurrence of hypoxia-reoxygenation sequences generates significant amounts of free radicals, particularly in moderate to severe OSA patients. Moreover, in addition to hypoxia, reactive oxygen species (ROS) are potential inducers of the hypoxia inducible transcription factor-1 (HIF-1) that promotes the transcription of numerous adaptive genes some of which being deleterious for the cardiovascular system, such as the endothelin-1 gene. This review will focus on the involvement of the ROS-HIF-1-endotelin signaling pathway in OSA and intermittent hypoxia and discuss current and potential therapeutic approaches targeting this pathway to treat or prevent cardiovascular disease in moderate to severe OSA patients. PMID:27492897

Transient-Switch-Signal Suppressor

Science.gov (United States)

Bozeman, Richard J., Jr.

1995-01-01

Circuit delays transmission of switch-opening or switch-closing signal until after preset suppression time. Used to prevent transmission of undesired momentary switch signal. Basic mode of operation simple. Beginning of switch signal initiates timing sequence. If switch signal persists after preset suppression time, circuit transmits switch signal to external circuitry. If switch signal no longer present after suppression time, switch signal deemed transient, and circuit does not pass signal on to external circuitry, as though no transient switch signal. Suppression time preset at value large enough to allow for damping of underlying pressure wave or other mechanical transient.

micROS: a morphable, intelligent and collective robot operating system.

Science.gov (United States)

Yang, Xuejun; Dai, Huadong; Yi, Xiaodong; Wang, Yanzhen; Yang, Shaowu; Zhang, Bo; Wang, Zhiyuan; Zhou, Yun; Peng, Xuefeng

2016-01-01

Robots are developing in much the same way that personal computers did 40 years ago, and robot operating system is the critical basis. Current robot software is mainly designed for individual robots. We present in this paper the design of micROS, a morphable, intelligent and collective robot operating system for future collective and collaborative robots. We first present the architecture of micROS, including the distributed architecture for collective robot system as a whole and the layered architecture for every single node. We then present the design of autonomous behavior management based on the observe-orient-decide-act cognitive behavior model and the design of collective intelligence including collective perception, collective cognition, collective game and collective dynamics. We also give the design of morphable resource management, which first categorizes robot resources into physical, information, cognitive and social domains, and then achieve morphability based on self-adaptive software technology. We finally deploy micROS on NuBot football robots and achieve significant improvement in real-time performance.

Organizing of delay, input gate and memory of proportional chamber channel basing on D-trigger

International Nuclear Information System (INIS)

Vladimirov, S.V.; Kuzichev, V.F.; Rabin, N.V.

1980-01-01

Economical organization of delay, input gate and proportional chamber (PC) channel memory on the 155 TM2 D trigger basis is described. The channel consists of an amplifier; delay element permitting to synchronize PC signal and recording strobe-signal; input gate, where coincidence of the above signals occurs; memory element, where the data from a wire are recorded and stored; read gate through which the data are transmitted for further processing. Presented is one of the versions of circuit solution for delay element, input gate and momory element. Flowsheet peculiarity is the simplicity of fabrication and tuning as well as low cost of the device

Vitamin K2 Induces Mitochondria-Related Apoptosis in Human Bladder Cancer Cells via ROS and JNK/p38 MAPK Signal Pathways.

Science.gov (United States)

Duan, Fengsen; Yu, Yuejin; Guan, Rijian; Xu, Zhiliang; Liang, Huageng; Hong, Ling

2016-01-01

The effects of vitamin K2 on apoptosis in a variety of cancer cells have been well established in previous studies. However, the apoptotic effect of vitamin K2 on bladder cancer cells has not been evaluated. The aim of this study is to examine the apoptotic activity of Vitamin K2 in bladder cancer cells and investigate the underlying mechanism. In this study, Vitamin K2 induced apoptosis in bladder cancer cells through mitochondria pathway including loss of mitochondria membrane potential, cytochrome C release and caspase-3 cascade. Furthermore, the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 MAPK was detected in Vitamin K2-treated cells and both SP600125 (an inhibitor of JNK) and SB203580 (an inhibitor of p38 MAPK) completely abolished the Vitamin K2-induced apoptosis and loss of mitochondria membrane potential. Moreover, the generation of reactive oxygen species (ROS) was detected in bladder cancer cells, upon treatment of vitamin K2 and the anti-oxidant N-acetyl cysteine (NAC) almost blocked the Vitamin K2-triggered apoptosis, loss of mitochondria membrane potential and activation of JNK and p38 MAPK. Taken together, these findings revealed that Vitamin K2 induces apoptosis in bladder cancer cells via ROS-mediated JNK/p38 MAPK and Mitochondrial pathways.

ROS-TMS and Big Sensor Box: Platforms for Informationally Structured Environment

OpenAIRE

倉爪, 亮; ユンソク, ピョ; 辻, 徳生; 河村, 晃宏

2017-01-01

This paper proposes new software and hardware platforms for an informationally structured environment named ROS-TMS and Big Sensor Box. We started the development of a management system for an informationally structured environment named TMS (Town Management System) in Robot Town Project in 2005. Since then we are continuing our efforts for the improvement of the performance and the enhancement of the functions of the TMS. Recently, we launched a new version of TMS named ROS-TMS, which resolv...

Oxidative Stress, Redox Signaling, and Autophagy: Cell Death Versus Survival

Science.gov (United States)

Navarro-Yepes, Juliana; Burns, Michaela; Anandhan, Annadurai; Khalimonchuk, Oleh; del Razo, Luz Maria; Quintanilla-Vega, Betzabet; Pappa, Aglaia; Panayiotidis, Mihalis I.

2014-01-01

Abstract Significance: The molecular machinery regulating autophagy has started becoming elucidated, and a number of studies have undertaken the task to determine the role of autophagy in cell fate determination within the context of human disease progression. Oxidative stress and redox signaling are also largely involved in the etiology of human diseases, where both survival and cell death signaling cascades have been reported to be modulated by reactive oxygen species (ROS) and reactive nitrogen species (RNS). Recent Advances: To date, there is a good understanding of the signaling events regulating autophagy, as well as the signaling processes by which alterations in redox homeostasis are transduced to the activation/regulation of signaling cascades. However, very little is known about the molecular events linking them to the regulation of autophagy. This lack of information has hampered the understanding of the role of oxidative stress and autophagy in human disease progression. Critical Issues: In this review, we will focus on (i) the molecular mechanism by which ROS/RNS generation, redox signaling, and/or oxidative stress/damage alter autophagic flux rates; (ii) the role of autophagy as a cell death process or survival mechanism in response to oxidative stress; and (iii) alternative mechanisms by which autophagy-related signaling regulate mitochondrial function and antioxidant response. Future Directions: Our research efforts should now focus on understanding the molecular basis of events by which autophagy is fine tuned by oxidation/reduction events. This knowledge will enable us to understand the mechanisms by which oxidative stress and autophagy regulate human diseases such as cancer and neurodegenerative disorders. Antioxid. Redox Signal. 21, 66–85. PMID:24483238

Knockdown of hepatoma-derived growth factor-related protein-3 induces apoptosis of H1299 cells via ROS-dependent and p53-independent NF-κB activation

International Nuclear Information System (INIS)

Yun, Hong Shik; Baek, Jeong-Hwa; Yim, Ji-Hye; Lee, Su-Jae; Lee, Chang-Woo; Song, Jie-Young; Um, Hong-Duck; Park, Jong Kuk; Park, In-Chul; Hwang, Sang-Gu

2014-01-01

Highlights: • HRP-3 is a radiation- and anticancer drug-responsive protein in H1299 cells. • Depletion of HRP-3 induces apoptosis of radio- and chemoresistant H1299 cells. • Depletion of HRP-3 promotes ROS generation via inhibition of the Nrf2/HO-1 pathway. • ROS generation enhances NF-κB activity, which acts as an upstream signal in the c-Myc/Noxa apoptotic pathway. - Abstract: We previously identified hepatoma-derived growth factor-related protein-3 (HRP-3) as a radioresistant biomarker in p53 wild-type A549 cells and found that p53-dependent induction of the PUMA pathway was a critical event in regulating the radioresistant phenotype. Here, we found that HRP-3 knockdown regulates the radioresistance of p53-null H1299 cells through a distinctly different molecular mechanism. HRP-3 depletion was sufficient to cause apoptosis of H1299 cells by generating substantial levels of reactive oxygen species (ROS) through inhibition of the Nrf2/HO-1 antioxidant pathway. Subsequent, ROS-dependent and p53-independent NF-κB activation stimulated expression of c-Myc and Noxa proteins, thereby inducing the apoptotic machinery. Our results thus extend the range of targets for the development of new drugs to treat both p53 wild-type or p53-null radioresistant lung cancer cells

A monolithic constant-fraction discriminator using distributed R-C delay-line shaping

International Nuclear Information System (INIS)

Simpson, M.L.; Young, G.R.; Xu, M.

1995-01-01

A monolithic, CMOS, constant-fraction discriminator (CFD) was fabricated in the Orbit Semiconductor, 1.2 μ N-well process. This circuit uses an on-chip, distributed, R-C delay-line to realize the constant-fraction shaping. The delay-line is constructed from a narrow, 500-μ serpentine layer of polysilicon above a wide, grounded, second layer of polysilicon. This R-C delay-line generates about 1.1 ns of delay for 5 ns risetime signals with a slope degradation of only ≅ 15% and an amplitude reduction of about 6.1%. The CFD also features an automatic walk adjustment. The entire circuit, including the delay line, has a 200 μ pitch and is 950 μ long. The walk for a 5 ns risetime signal was measured as ± 100 ps over the 100:1 dynamic range from -15 mV to -1.5 mV. to -1.5 V. The CFD consumes 15 mW

Development of an in vitro photosafety evaluation method utilizing intracellular ROS production in THP-1 cells.

Science.gov (United States)

Toyoda, Akemi; Itagaki, Hiroshi

2018-01-01

Photoreactive compounds that may experience exposure to ultraviolet (UV) radiation can lead to the intracellular production of reactive oxygen species (ROS), which may cause phototoxic and photoallergenic responses. Here, we developed a novel in vitro photosafety assay and investigated whether it could be used to predict phototoxicity and photosensitivity by measuring changes in intracellular ROS production. THP-1 cells that had previously taken up 5-(and-6)-carboxy-2',7'-difluorodihydrofluorescein diacetate (carboxy-H 2 DFFDA), a ROS-sensitive fluorescent reagent, were exposed to photoreactive substances such as phototoxic and photoallergenic materials and then subjected to with UV-A irradiation (5 J/cm 2 ). The fluorescence intensity was subsequently measured using a flow cytometer, and the intracellular ROS production was calculated. A statistically significant increase in ROS following treatment with photoreactive substances was observed in cells irradiated with UV-A. In contrast, no significant increase was observed for non-photoreactive substances in comparison to the control solution. Next, to confirm the impact of intracellular ROS on the photosensitive response, changes in CD86 and CD54 expression were measured following quencher addition during the photo human cell line activation test (photo h-CLAT). The results confirmed the reduction of CD86 and CD54 expression in response to photoallergenic substances following quencher addition. Together, these findings suggest that intracellular ROS production is involved in photosensitizing reactions. Therefore, we suggest that the developed method utilizing intracellular ROS production as an index may be useful as a novel in vitro evaluation tool for photoreactive substances.

Endogenous cytokinin overproduction modulates ROS homeostasis and decreases salt stress resistance in Arabidopsis thaliana

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Yanping eWang

2015-11-01

Full Text Available Cytokinins in plants are crucial for numerous biological processes, including seed germination, cell division and differentiation, floral initiation and adaptation to abiotic stresses. The salt stress can promote reactive oxygen species (ROS production in plants which are highly toxic and ultimately results in oxidative stress. However, the correlation between endogenous cytokinin production and ROS homeostasis in responding to salt stress is poorly understood. In this study, we analyzed the correlation of overexpressing the cytokinin biosynthetic gene AtIPT8 (adenosine phosphate-isopentenyl transferase 8 and the response of salt stress in Arabidopsis. Overproduction of cytokinins, which was resulted by the inducible overexpression of AtIPT8, significantly inhibited the primary root growth and true leaf emergence, especially under the conditions of exogenous salt, glucose and mannitol treatments. Upon cytokinin overproduction, the salt stress resistance was declined, and resulted in less survival rates and chlorophyll content. Interestingly, ROS production was obviously increased with the salt treatment, accompanied by endogenously overproduced cytokinins. The activities of CAT and SOD, which are responsible for scavenging ROS, were also affected. Transcription profiling revealed that the differential expressions of ROS-producing and scavenging related genes, the photosynthesis-related genes and stress responsive genes were existed in transgenic plants of overproducing cytokinins. Our results suggested that broken in the homeostasis of cytokinins in plant cells could modulate the salt stress responses through a ROS-mediated regulation in Arabidopsis.

Reactive oxygen species mediate Cr(VI)-induced carcinogenesis through PI3K/AKT-dependent activation of GSK-3β/β-catenin signaling

International Nuclear Information System (INIS)

Son, Young-Ok; Pratheeshkumar, Poyil; Wang, Lei; Wang, Xin; Fan, Jia; Kim, Dong-Hern; Lee, Ju-Yeon; Zhang, Zhuo; Lee, Jeong-Chae; Shi, Xianglin

2013-01-01

Cr(VI) compounds are known human carcinogens that primarily target the lungs. Cr(VI) produces reactive oxygen species (ROS), but the exact effects of ROS on the signaling molecules involved in Cr(VI)-induced carcinogenesis have not been extensively studied. Chronic exposure of human bronchial epithelial cells to Cr(VI) at nanomolar concentrations (10–100 nM) for 3 months not only induced cell transformation, but also increased the potential of these cells to invade and migrate. Injection of Cr(VI)-stimulated cells into nude mice resulted in the formation of tumors. Chronic exposure to Cr(VI) increased levels of intracellular ROS and antiapoptotic proteins. Transfection with catalase or superoxide dismutase (SOD) prevented Cr(VI)-mediated increases in colony formation, cell invasion, migration, and xenograft tumors. While chronic Cr(VI) exposure led to activation of signaling cascades involving PI3K/AKT/GSK-3β/β-catenin and PI3K/AKT/mTOR, transfection with catalase or SOD markedly inhibited Cr(VI)-mediated activation of these signaling proteins. Inhibitors specific for AKT or β-catenin almost completely suppressed the Cr(VI)-mediated increase in total and active β-catenin proteins and colony formation. In particular, Cr(VI) suppressed autophagy of epithelial cells under nutrition deprivation. Furthermore, there was a marked induction of AKT, GSK-3β, β-catenin, mTOR, and carcinogenic markers in tumor tissues formed in mice after injection with Cr(VI)-stimulated cells. Collectively, our findings suggest that ROS is a key mediator of Cr(VI)-induced carcinogenesis through the activation of PI3K/AKT-dependent GSK-3β/β-catenin signaling and the promotion of cell survival mechanisms via the inhibition of apoptosis and autophagy. - Highlights: • Chronic exposure to Cr(VI) induces carcinogenic properties in BEAS-2B cells. • ROS play an important role in Cr(VI)-induced tumorigenicity of BEAS-2B cells. • PI3K/AKT/GSK-3β/β-catenin signaling involved in Cr