WorldWideScience

Sample records for monophosphate cgmp signaling

  1. Correlative intravital imaging of cGMP signals and vasodilation in mice

    Directory of Open Access Journals (Sweden)

    Martin eThunemann

    2014-10-01

    Full Text Available Cyclic guanosine monophosphate (cGMP is an important signaling molecule and drug target in the cardiovascular system. It is well known that stimulation of the vascular nitric oxide (NO-cGMP pathway results in vasodilation. However, the spatiotemporal dynamics of cGMP signals themselves and the cGMP concentrations within specific cardiovascular cell types in health, disease, and during pharmacotherapy with cGMP-elevating drugs are largely unknown. To facilitate the analysis of cGMP signaling in vivo, we have generated transgenic mice that express fluorescence resonance energy transfer (FRET-based cGMP sensor proteins. Here, we describe two models of intravital FRET/cGMP imaging in the vasculature of cGMP sensor mice: (1 epifluorescence-based ratio imaging in resistance-type vessels of the cremaster muscle and (2 ratio imaging by multiphoton microscopy within the walls of subcutaneous blood vessels accessed through a dorsal skinfold chamber. Both methods allow simultaneous monitoring of NO-induced cGMP transients and vasodilation in living mice. Detailed protocols of all steps necessary to perform and evaluate intravital imaging experiments of the vasculature of anesthetized mice including surgery, imaging, and data evaluation are provided. An image segmentation approach is described to estimate FRET/cGMP changes within moving structures such as the vessel wall during vasodilation. The methods presented herein should be useful to visualize cGMP or other biochemical signals that are detectable with FRET-based biosensors, such as cyclic adenosine monophosphate or Ca2+, and to correlate them with respective vascular responses. With further refinement and combination of transgenic mouse models and intravital imaging technologies, we envision an exciting future, in which we are able to ‘watch’ biochemistry, (patho physiology, and pharmacotherapy in the context of a living mammalian organism.

  2. The role of cGMP signalling in regulating life cycle progression of Plasmodium.

    OpenAIRE

    Hopp, CS; Bowyer, PW; Baker, DA

    2012-01-01

    The 3′-5′-cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) is the main mediator of cGMP signalling in the malaria parasite. This article reviews the role of PKG in Plasmodium falciparum during gametogenesis and blood stage schizont rupture, as well as the role of the Plasmodium berghei orthologue in ookinete differentiation and motility, and liver stage schizont development. The current views on potential effector proteins downstream of PKG and the mechanisms that may regu...

  3. The role of cGMP signalling in regulating life cycle progression of Plasmodium.

    Science.gov (United States)

    Hopp, Christine S; Bowyer, Paul W; Baker, David A

    2012-08-01

    The 3'-5'-cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) is the main mediator of cGMP signalling in the malaria parasite. This article reviews the role of PKG in Plasmodium falciparum during gametogenesis and blood stage schizont rupture, as well as the role of the Plasmodium berghei orthologue in ookinete differentiation and motility, and liver stage schizont development. The current views on potential effector proteins downstream of PKG and the mechanisms that may regulate cyclic nucleotide levels are presented. Copyright © 2012 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  4. cGMP signalling : different ways to create a pathway

    NARCIS (Netherlands)

    Roelofs, Jeroen; Smith, Janet L.; Haastert, Peter J.M. van

    Recently, a novel cGMP signalling cascade was uncovered in Dictyostelium, a eukaryote that diverged from the lineage leading to metazoa after plants and before yeast. In both Dictyostelium and metazoa, the ancient cAMP-binding (cNB) motif of bacterial CAP has been modified and assembled with other

  5. Cyclic Nucleotide Monophosphates and Their Cyclases in Plant Signaling

    KAUST Repository

    Gehring, Christoph A.

    2017-10-04

    The cyclic nucleotide monophosphates (cNMPs), and notably 3′,5′-cyclic guanosine monophosphate (cGMP) and 3′,5′-cyclic adenosine monophosphate (cAMP) are now accepted as key signaling molecules in many processes in plants including growth and differentiation, photosynthesis, and biotic and abiotic defense. At the single molecule level, we are now beginning to understand how cNMPs modify specific target molecules such as cyclic nucleotide-gated channels, while at the systems level, a recent study of the Arabidopsis cNMP interactome has identified novel target molecules with specific cNMP-binding domains. A major advance came with the discovery and characterization of a steadily increasing number of guanylate cyclases (GCs) and adenylate cyclases (ACs). Several of the GCs are receptor kinases and include the brassinosteroid receptor, the phytosulfokine receptor, the Pep receptor, the plant natriuretic peptide receptor as well as a nitric oxide sensor. We foresee that in the near future many more molecular mechanisms and biological roles of GCs and ACs and their catalytic products will be discovered and further establish cNMPs as a key component of plant responses to the environment.

  6. Cyclic Nucleotide Monophosphates and Their Cyclases in Plant Signaling

    KAUST Repository

    Gehring, Christoph A; Turek, Ilona S.

    2017-01-01

    The cyclic nucleotide monophosphates (cNMPs), and notably 3′,5′-cyclic guanosine monophosphate (cGMP) and 3′,5′-cyclic adenosine monophosphate (cAMP) are now accepted as key signaling molecules in many processes in plants including growth and differentiation, photosynthesis, and biotic and abiotic defense. At the single molecule level, we are now beginning to understand how cNMPs modify specific target molecules such as cyclic nucleotide-gated channels, while at the systems level, a recent study of the Arabidopsis cNMP interactome has identified novel target molecules with specific cNMP-binding domains. A major advance came with the discovery and characterization of a steadily increasing number of guanylate cyclases (GCs) and adenylate cyclases (ACs). Several of the GCs are receptor kinases and include the brassinosteroid receptor, the phytosulfokine receptor, the Pep receptor, the plant natriuretic peptide receptor as well as a nitric oxide sensor. We foresee that in the near future many more molecular mechanisms and biological roles of GCs and ACs and their catalytic products will be discovered and further establish cNMPs as a key component of plant responses to the environment.

  7. Potentiation of cGMP signaling increases oxygen delivery and oxidative metabolism in contracting skeletal muscle of older but not young humans

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Piil, Peter Bergmann; Egelund, Jon

    2015-01-01

    regulation remain unresolved. Cyclic guanosine monophosphate (cGMP) is one of the main second messengers that mediate smooth muscle vasodilation and alterations in cGMP signaling could, therefore, be one mechanism by which skeletal muscle perfusion is impaired with advancing age. The current study aimed...... to evaluate the effect of inhibiting the main enzyme involved in cGMP degradation, phosphodiesterase 5 (PDE5), on blood flow and O2 delivery in contracting skeletal muscle of young and older humans. A group of young (23 ± 1 years) and a group of older (72 ± 2 years) male human subjects performed submaximal...... in the older subjects correlated with the increase in leg O2 uptake (r (2) = 0.843). These findings suggest an insufficient O2 delivery to the contracting skeletal muscle of aged individuals and that reduced cGMP availability is a novel mechanism underlying impaired skeletal muscle perfusion with advancing age....

  8. Decreased levels of guanosine 3', 5'-monophosphate (cGMP) in cerebrospinal fluid (CSF) are associated with cognitive decline and amyloid pathology in Alzheimer's disease.

    Science.gov (United States)

    Ugarte, Ana; Gil-Bea, Francisco; García-Barroso, Carolina; Cedazo-Minguez, Ángel; Ramírez, M Javier; Franco, Rafael; García-Osta, Ana; Oyarzabal, Julen; Cuadrado-Tejedor, Mar

    2015-06-01

    Levels of the cyclic nucleotides guanosine 3', 5'-monophosphate (cGMP) or adenosine 3', 5'-monophosphate (cAMP) that play important roles in memory processes are not characterized in Alzheimer's disease (AD). The aim of this study was to analyse the levels of these nucleotides in cerebrospinal fluid (CSF) samples from patients diagnosed with clinical and prodromal stages of AD and study the expression level of the enzymes that hydrolyzed them [phosphodiesterases (PDEs)] in the brain of AD patients vs. For cGMP and cAMP CSF analysis, the cohort (n = 79) included cognitively normal participants (subjective cognitive impairment), individuals with stable mild cognitive impairment or AD converters (sMCI and cMCI), and mild AD patients. A high throughput liquid chromatography-tandem mass spectrometry method was used. Interactions between CSF cGMP or cAMP with mini-mental state examination (MMSE) score, CSF Aβ(1-42) and CSF p-tau were analysed. For PDE4, 5, 9 and 10 expression analysis, brains of AD patients vs. controls (n = 7 and n = 8) were used. cGMP, and not cAMP levels, were significantly lower in the CSF of patients diagnosed with mild AD when compared with nondemented controls. CSF levels of cGMP showed a significant association with MMSE-diagnosed clinical dementia and with CSF biomarker Aβ42 in AD patients. Significant increase in PDE5 expression was detected in temporal cortex of AD patients compared with that of age-matched healthy control subjects. No changes in the expression of others PDEs were detected. These results support the potential involvement of cGMP in the pathological and clinical development of AD. The cGMP reduction in early stages of AD might participate in the aggravation of amyloid pathology and cognitive decline. © 2014 British Neuropathological Society.

  9. cGMP Signaling in the Cardiovascular System—The Role of Compartmentation and Its Live Cell Imaging

    Science.gov (United States)

    Bork, Nadja I.; Nikolaev, Viacheslav O.

    2018-01-01

    The ubiquitous second messenger 3′,5′-cyclic guanosine monophosphate (cGMP) regulates multiple physiologic processes in the cardiovascular system. Its intracellular effects are mediated by stringently controlled subcellular microdomains. In this review, we will illustrate the current techniques available for real-time cGMP measurements with a specific focus on live cell imaging methods. We will also discuss currently accepted and emerging mechanisms of cGMP compartmentation in the cardiovascular system. PMID:29534460

  10. Receptors and cGMP signalling mechanism for E. coli enterotoxin in opossum kidney

    International Nuclear Information System (INIS)

    Forte, L.R.; Krause, W.J.; Freeman, R.H.

    1988-01-01

    Receptors for the heat-stable enterotoxin produced by Escherichia coli were found in the kidney and intestine of the North American opossum and in cultured renal cell lines. The enterotoxin markedly increased guanosine 3',5'-cyclic monophosphate (cGMP) production in slices of kidney cortex and medulla, in suspensions of intestinal mucosa, and in the opossum kidney (OK) and rat kangaroo kidney (PtK-2) cell lines. In contrast, atrial natriuretic factor elicited much smaller increases in cGMP levels of kidney, intestine, or cultured kidney cell lines. The enterotoxin receptors in OK cells had a molecular mass of approximately 120 kDa when measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of receptors crosslinked with 125 I-enterotoxin. The occurrence of receptors for the E. coli peptide in OK implies that these receptors may be involved in the regulation of renal tubular function in the opossum. E. coli enterotoxin caused a much larger increase in urine cGMP excretion than did atrial natriuretic factor when these peptides were injected intravenously into opossums. However, atrial natriuretic factor elicited a marked diuresis, natriuresis, and increased urinary excretion of calcium, phosphate, potassium, and magnesium. In contrast, the enterotoxin did not acutely influence OK fluid and electrolyte excretion. Thus the substantial increase in cGMP synthesis produced by the bacterial peptide in OK cortex and medulla in vitro and the increased renal excretion of cGMP in vivo were not associated with changes in electrolyte or water excretion. Whether cGMP represents a second messenger molecule in the kidney is an interesting question that was raised but not answered in this series of experiments

  11. A novel crosstalk between Alk7 and cGMP signaling differentially regulates brown adipocyte function

    Directory of Open Access Journals (Sweden)

    Aileen Balkow

    2015-08-01

    Conclusions: We found a so far unknown crosstalk between cGMP and Alk7 signaling pathways. Tight regulation of Alk7 is required for efficient differentiation of brown adipocytes. Alk7 has differential effects on adipogenic differentiation and the development of the thermogenic program in brown adipocytes.

  12. cGMP signaling as a target for the prevention and treatment of breast cancer.

    Science.gov (United States)

    Windham, Perrin F; Tinsley, Heather N

    2015-04-01

    One in eight women in the United States will be diagnosed with invasive breast cancer in her lifetime. Advances in therapeutic strategies, diagnosis, and improved awareness have resulted in a significant reduction in breast cancer related mortality. However, there is a continued need for more effective and less toxic drugs for both the prevention and the treatment of breast cancer in order to see a continued decline in the morbidity and mortality associated with this disease. Recent studies suggest that the cGMP signaling pathway may be aberrantly regulated in breast cancer. As such, this pathway may serve as a source of novel targets for future breast cancer drug discovery efforts. This review provides an overview of cGMP signaling in normal physiology and in breast cancer as well as current strategies being investigated for targeting this pathway in breast cancer. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Systemic induction of NO-, redox- and cGMP signalling in the pumpkin extrafascicular phloem upon local leaf wounding

    Directory of Open Access Journals (Sweden)

    Frank eGaupels

    2016-02-01

    Full Text Available Cucurbits developed the unique extrafascicular phloem (EFP as a defensive structure against herbivorous animals. Mechanical leaf injury was previously shown to induce a systemic wound response in the EFP of pumpkin (Cucurbita maxima. Here, we demonstrate that the phloem antioxidant system and protein modifications by NO are strongly regulated during this process. Activities of the central antioxidant enzymes dehydroascorbate reductase, glutathione reductase and ascorbate reductase were rapidly down-regulated at 30 min with a second minimum at 24 h after wounding. As a consequence levels of total ascorbate and glutathione also decreased with similar bi-phasic kinetics. These results hint towards a wound-induced shift in the redox status of the EFP. Nitric oxide (NO is another important player in stress-induced redox signalling in plants. Therefore, we analysed NO-dependent protein modifications in the EFP. Six to 48 h after leaf damage total S-nitrosothiol content and protein S-nitrosylation were clearly reduced, which was contrasted by a pronounced increase in protein tyrosine nitration. Collectively, these findings suggest that NO-dependent S-nitrosylation turned into peroxynitrite-mediated protein nitration upon a stress-induced redox shift probably involving the accumulation of reactive oxygen species within the EFP. Using the biotin switch assay and anti-nitrotyrosine antibodies we identified 9 candidate S-nitrosylated and 6 candidate tyrosine-nitrated phloem proteins. The wound-responsive Phloem Protein 16-1 (PP16-1 and Cyclophilin 18 (CYP18 as well as the 26.5 kD isoform of Phloem Protein 2 (PP2 were amenable to both NO modifications and could represent important redox-sensors within the cucurbit EFP. We also found that leaf injury triggered the systemic accumulation of cyclic guanosine monophosphate (cGMP in the EFP and discuss the possible function of this second messenger in systemic NO and redox signalling within the EFP.

  14. Development and validation of an LC-MS/MS method for quantification of cyclic guanosine 3',5'-monophosphate (cGMP) in clinical applications: a comparison with a EIA method.

    Science.gov (United States)

    Zhang, Yanhua; Dufield, Dawn; Klover, Jon; Li, Wenlin; Szekely-Klepser, Gabriella; Lepsy, Christopher; Sadagopan, Nalini

    2009-02-15

    An LC-MS/MS method was developed and validated to quantify endogenous cyclic guanosine 3',5'-monophosphate (cGMP) in human plasma. The LC-MS/MS and competitive enzyme immunoassay (EIA) assays were compared. cGMP concentrations of 20 human plasma samples were measured by both methods. For the MS-based assay, plasma samples were subjected to a simple protein precipitation procedure by acetonitrile prior to analysis by electrospray ionization LC-MS/MS. De-protonated analytes generated in negative ionization mode were monitored through multiple reaction monitoring (MRM). A stable isotope-labeled internal standard, (13)C(10),(15)N(5)-cGMP, which was biosynthesized in-house, was used in the LC-MS/MS method. The competitive EIA was validated using a commercially available cGMP fluorescence assay kit. The intra-assay accuracy and precision for MS-based assay for cGMP were 6-10.1% CV and -3.6% to 7.3% relative error (RE), respectively, while inter-assay precision and accuracy were 5.6-8.1% CV and -2.1% to 6.3% RE, respectively. The intra-assay accuracy and precision for EIA were 17.9-27.1% CV and -4.9% to 24.5% RE, respectively, while inter-assay precision and accuracy were 15.1-39.5% CV and -30.8% to 4.37% RE, respectively. Near the lower limits of detection, there was little correlation between the cGMP concentration values in human plasma generated by these two methods (R(2)=0.197, P=0.05). Overall, the MS-based assay offered better selectivity, recovery, precision and accuracy over a linear range of 0.5-20ng/mL. The LC-MS/MS method provides an effective tool for the quantitation of cGMP to support clinical mechanistic studies of curative pharmaceuticals.

  15. The brassinosteroid receptor BRI1 can generate cGMP enabling cGMP-dependent downstream signaling

    KAUST Repository

    Wheeler, Janet I.

    2017-05-08

    The brassinosteroid receptor BRASSINOSTEROID INSENSITIVE 1 (BRI1) is a member of the leucine rich repeat receptor like kinase family. The intracellular kinase domain of BRI1 is an active kinase and also encapsulates a guanylate cyclase catalytic centre. Using liquid chromatography tandem mass spectrometry, we confirmed that the recombinant cytoplasmic domain of BRI1 generates pmol amounts of cGMP per μg protein with a preference for magnesium over manganese as a co-factor. Importantly, a functional BRI1 kinase is essential for optimal cGMP generation. Therefore, the guanylate cyclase activity of BRI1 is modulated by the kinase while cGMP, the product of the guanylate cyclase, in turn inhibits BRI1 kinase activity. Furthermore, we show using Arabidopsis root cell cultures that cGMP rapidly potentiates phosphorylation of the downstream substrate BRASSINOSTEROID SIGNALING KINASE 1 (BSK1). Taken together, our results suggest that cGMP acts as a modulator that enhances downstream signaling while dampening signal generation from the receptor. This article is protected by copyright. All rights reserved.

  16. The brassinosteroid receptor BRI1 can generate cGMP enabling cGMP-dependent downstream signaling

    KAUST Repository

    Wheeler, Janet I.; Wong, Aloysius Tze; Marondedze, Claudius; Groen, Arnoud J.; Kwezi, Lusisizwe; Freihat, Lubna; Vyas, Jignesh; Raji, Misjudeen; Irving, Helen R.; Gehring, Christoph A

    2017-01-01

    The brassinosteroid receptor BRASSINOSTEROID INSENSITIVE 1 (BRI1) is a member of the leucine rich repeat receptor like kinase family. The intracellular kinase domain of BRI1 is an active kinase and also encapsulates a guanylate cyclase catalytic centre. Using liquid chromatography tandem mass spectrometry, we confirmed that the recombinant cytoplasmic domain of BRI1 generates pmol amounts of cGMP per μg protein with a preference for magnesium over manganese as a co-factor. Importantly, a functional BRI1 kinase is essential for optimal cGMP generation. Therefore, the guanylate cyclase activity of BRI1 is modulated by the kinase while cGMP, the product of the guanylate cyclase, in turn inhibits BRI1 kinase activity. Furthermore, we show using Arabidopsis root cell cultures that cGMP rapidly potentiates phosphorylation of the downstream substrate BRASSINOSTEROID SIGNALING KINASE 1 (BSK1). Taken together, our results suggest that cGMP acts as a modulator that enhances downstream signaling while dampening signal generation from the receptor. This article is protected by copyright. All rights reserved.

  17. Exercise training improves blood flow to contracting skeletal muscle of older men via enhanced cGMP signaling

    DEFF Research Database (Denmark)

    Piil, Peter Bergmann; Smith Jørgensen, Tue; Egelund, Jon

    2018-01-01

    Physical activity has the potential to offset age-related impairments in the regulation of blood flow and O2 delivery to the exercising muscles; however, the mechanisms underlying this effect of physical activity remain poorly understood. The present study examined the role of cGMP in training...... a period of aerobic high-intensity exercise training. To determine the role of cGMP signaling, pharmacological inhibition of phosphodiesterase 5 (PDE5) was performed. Before training, inhibition of PDE5 increased (P... group; however, these effects of PDE5 inhibition were not detected after training. These findings suggest a role for enhanced cGMP signaling in the training-induced improvement of regulation of blood flow in contracting skeletal muscle of older men....

  18. Differential Regulation of cGMP Signaling in Human Melanoma Cells at Altered Gravity: Simulated Microgravity Down-Regulates Cancer-Related Gene Expression and Motility

    Science.gov (United States)

    Ivanova, Krassimira; Eiermann, Peter; Tsiockas, Wasiliki; Hemmersbach, Ruth; Gerzer, Rupert

    2018-03-01

    Altered gravity is known to affect cellular function by changes in gene expression and cellular signaling. The intracellular signaling molecule cyclic guanosine-3',5'-monophosphate (cGMP), a product of guanylyl cyclases (GC), e.g., the nitric oxide (NO)-sensitive soluble GC (sGC) or natriuretic peptide-activated GC (GC-A/GC-B), is involved in melanocyte response to environmental stress. NO-sGC-cGMP signaling is operational in human melanocytes and non-metastatic melanoma cells, whereas up-regulated expression of GC-A/GC-B and inducible NO synthase (iNOS) are found in metastatic melanoma cells, the deadliest skin cancer. Here, we investigated the effects of altered gravity on the mRNA expression of NOS isoforms, sGC, GC-A/GC-B and multidrug resistance-associated proteins 4/5 (MRP4/MRP5) as selective cGMP exporters in human melanoma cells with different metastatic potential and pigmentation. A specific centrifuge (DLR, Cologne Germany) was used to generate hypergravity (5 g for 24 h) and a fast-rotating 2-D clinostat (60 rpm) to simulate microgravity values ≤ 0.012 g for 24 h. The results demonstrate that hypergravity up-regulates the endothelial NOS-sGC-MRP4/MRP5 pathway in non-metastatic melanoma cells, but down-regulates it in simulated microgravity when compared to 1 g. Additionally, the suppression of sGC expression and activity has been suggested to correlate inversely to tumor aggressiveness. Finally, hypergravity is ineffective in highly metastatic melanoma cells, whereas simulated microgravity down-regulates predominantly the expression of the cancer-related genes iNOS and GC-A/GC-B (shown additionally on protein levels) as well as motility in comparison to 1 g. The results suggest that future studies in real microgravity can benefit from considering GC-cGMP signaling as possible factor for melanocyte transformation.

  19. cGMP and NHR signaling co-regulate expression of insulin-like peptides and developmental activation of infective larvae in Strongyloides stercoralis.

    Directory of Open Access Journals (Sweden)

    Jonathan D Stoltzfus

    2014-07-01

    Full Text Available The infectious form of the parasitic nematode Strongyloides stercoralis is a developmentally arrested third-stage larva (L3i, which is morphologically similar to the developmentally arrested dauer larva in the free-living nematode Caenorhabditis elegans. We hypothesize that the molecular pathways regulating C. elegans dauer development also control L3i arrest and activation in S. stercoralis. This study aimed to determine the factors that regulate L3i activation, with a focus on G protein-coupled receptor-mediated regulation of cyclic guanosine monophosphate (cGMP pathway signaling, including its modulation of the insulin/IGF-1-like signaling (IIS pathway. We found that application of the membrane-permeable cGMP analog 8-bromo-cGMP potently activated development of S. stercoralis L3i, as measured by resumption of feeding, with 85.1 ± 2.2% of L3i feeding in 200 µM 8-bromo-cGMP in comparison to 0.6 ± 0.3% in the buffer diluent. Utilizing RNAseq, we examined L3i stimulated with DMEM, 8-bromo-cGMP, or the DAF-12 nuclear hormone receptor (NHR ligand Δ7-dafachronic acid (DA--a signaling pathway downstream of IIS in C. elegans. L3i stimulated with 8-bromo-cGMP up-regulated transcripts of the putative agonistic insulin-like peptide (ILP -encoding genes Ss-ilp-1 (20-fold and Ss-ilp-6 (11-fold in comparison to controls without stimulation. Surprisingly, we found that Δ7-DA similarly modulated transcript levels of ILP-encoding genes. Using the phosphatidylinositol-4,5-bisphosphate 3-kinase inhibitor LY294002, we demonstrated that 400 nM Δ7-DA-mediated activation (93.3 ± 1.1% L3i feeding can be blocked using this IIS inhibitor at 100 µM (7.6 ± 1.6% L3i feeding. To determine the tissues where promoters of ILP-encoding genes are active, we expressed promoter::egfp reporter constructs in transgenic S. stercoralis post-free-living larvae. Ss-ilp-1 and Ss-ilp-6 promoters are active in the hypodermis and neurons and the Ss-ilp-7 promoter is active in the

  20. Plasma levels of cAMP, cGMP and CGRP in sildenafil-induced headache

    DEFF Research Database (Denmark)

    Kruuse, Christina Rostrup; Frandsen, E; Schifter, S

    2004-01-01

    Sildenafil, a selective inhibitor of the cyclic guanosine monophosphate (cGMP) degrading phosphodiestrase 5 (PDE5), induced migraine without aura in 10 of 12 migraine patients and in healthy subjects it induced significantly more headache than placebo. The aim of the present study was to determine...... whether the pain-inducing effects of sildenafil would be reflected in plasma levels of important signalling molecules in migraine: cGMP, cyclic adenosine monophosphate (cAMP) and calcitonin gene-related peptide (CGRP). Ten healthy subjects (four women, six men) and 12 patients (12 women) suffering from...... migraine without aura were included in two separate double-blind, placebo-controlled, cross-over studies in which placebo or sildenafil 100 mg was administered orally. Plasma levels of CGRP, cAMP and cGMP were determined in blood from the antecubital vein. Despite the ability of sildenafil to induce...

  1. Angiotensin II increases phosphodiesterase 5A expression in vascular smooth muscle cells: A mechanism by which angiotensin II antagonizes cGMP signaling

    Science.gov (United States)

    Kim, Dongsoo; Aizawa, Toru; Wei, Heng; Pi, Xinchun; Rybalkin, Sergei D.; Berk, Bradford C.; Yan, Chen

    2014-01-01

    Angiotensin II (Ang II) and nitric oxide (NO)/natriuretic peptide (NP) signaling pathways mutually regulate each other. Imbalance of Ang II and NO/NP has been implicated in the pathophysiology of many vascular diseases. cGMP functions as a key mediator in the interaction between Ang II and NO/NP. Cyclic nucleotide phosphodiesterase 5A (PDE5A) is important in modulating cGMP signaling by hydrolyzing cGMP in vascular smooth muscle cells (VSMC). Therefore, we examined whether Ang II negatively modulates intracellular cGMP signaling in VSMC by regulating PDE5A. Ang II rapidly and transiently increased PDE5A mRNA levels in rat aortic VSMC. Upregulation of PDE5A mRNA was associated with a time-dependent increase of both PDE5 protein expression and activity. Increased PDE5A mRNA level was transcription-dependent and mediated by the Ang II type 1 receptor. Ang II-mediated activation of extracellular signal-regulated kinases 1/2 (ERK1/2) was essential for Ang II-induced PDE5A upregulation. Pretreatment of VSMC with Ang II inhibited C-type NP (CNP) stimulated cGMP signaling, such as cGMP dependent protein kinase (PKG)-mediated phosphorylation of vasodilator-stimulated-phosphoprotein (VASP). Ang II-mediated inhibition of PKG was blocked when PDE5 activity was decreased by selective PDE5 inhibitors, suggesting that upregulation of PDE5A expression is an important mechanism for Ang II to attenuate cGMP signaling. PDE5A may also play a critical role in the growth promoting effects of Ang II because inhibition of PDE5A activity significantly decreased Ang II-stimulated VSMC growth. These observations establish a new mechanism by which Ang II antagonizes cGMP signaling and stimulates VSMC growth. PMID:15623434

  2. Heat shock factor-1 intertwines insulin/IGF-1, TGF-β and cGMP signaling to control development and aging

    Directory of Open Access Journals (Sweden)

    Barna János

    2012-11-01

    Full Text Available Abstract Background Temperature affects virtually all cellular processes. A quick increase in temperature challenges the cells to undergo a heat shock response to maintain cellular homeostasis. Heat shock factor-1 (HSF-1 functions as a major player in this response as it activates the transcription of genes coding for molecular chaperones (also called heat shock proteins that maintain structural integrity of proteins. However, the mechanisms by which HSF-1 adjusts fundamental cellular processes such as growth, proliferation, differentiation and aging to the ambient temperature remain largely unknown. Results We demonstrate here that in Caenorhabditis elegans HSF-1 represses the expression of daf-7 encoding a TGF-β (transforming growth factor-beta ligand, to induce young larvae to enter the dauer stage, a developmentally arrested, non-feeding, highly stress-resistant, long-lived larval form triggered by crowding and starvation. Under favorable conditions, HSF-1 is inhibited by crowding pheromone-sensitive guanylate cyclase/cGMP (cyclic guanosine monophosphate and systemic nutrient-sensing insulin/IGF-1 (insulin-like growth factor-1 signaling; loss of HSF-1 activity allows DAF-7 to promote reproductive growth. Thus, HSF-1 interconnects the insulin/IGF-1, TGF-β and cGMP neuroendocrine systems to control development and longevity in response to diverse environmental stimuli. Furthermore, HSF-1 upregulates another TGF-β pathway-interacting gene, daf-9/cytochrome P450, thereby fine-tuning the decision between normal growth and dauer formation. Conclusion Together, these results provide mechanistic insight into how temperature, nutrient availability and population density coordinately influence development, lifespan, behavior and stress response through HSF-1.

  3. The brassinosteroid receptor BRI1 can generate cGMP enabling cGMP-dependent downstream signaling

    CSIR Research Space (South Africa)

    Wheeler, J

    2017-06-01

    Full Text Available ) with the ll PickUp Injection mode using the loading pump at 15 ll min�1 flow rate for 3 min. Samples were then loaded on a RSLC, 75 lm 9 500 mm, nanoVi- per, C18, 2 lm, 100 �A column (Acclaim, PepMap) retrofitted to an EASY-spray source with a flow rate of 300... receptor BRI1 can generate cGMP enabling cGMP-dependent downstream signaling Janet I. Wheeler1,2,†, Aloysius Wong3,4, Claudius Marondedze3,5, Arnoud J. Groen5, Lusisizwe Kwezi1,6, Lubna Freihat1, Jignesh Vyas1, Misjudeen A. Raji7, Helen R. Irving1...

  4. A conjugate of decyltriphenylphosphonium with plastoquinone can carry cyclic adenosine monophosphate, but not cyclic guanosine monophosphate, across artificial and natural membranes.

    Science.gov (United States)

    Firsov, Alexander M; Rybalkina, Irina G; Kotova, Elena A; Rokitskaya, Tatyana I; Tashlitsky, Vadim N; Korshunova, Galina A; Rybalkin, Sergei D; Antonenko, Yuri N

    2018-02-01

    The present study demonstrated for the first time the interaction between adenosine 3',5'-cyclic monophosphate (cAMP), one of the most important signaling compounds in living organisms, and the mitochondria-targeted antioxidant plastoquinonyl-decyltriphenylphosphonium (SkQ1). The data obtained on model liquid membranes and human platelets revealed the ability of SkQ1 to selectively transport cAMP, but not guanosine 3',5'-cyclic monophosphate (cGMP), across both artificial and natural membranes. In particular, SkQ1 elicited translocation of cAMP from the source to the receiving phase of a Pressman-type cell, while showing low activity with cGMP. Importantly, only conjugate with plastoquinone, but not dodecyl-triphenylphosphonium, was effective in carrying cAMP. In human platelets, SkQ1 also appeared to serve as a carrier of cAMP, but not cGMP, from outside to inside the cell, as measured by phosphorylation of the vasodilator stimulated phosphoprotein. The SkQ1-induced transfer of cAMP across the plasma membrane found here can be tentatively suggested to interfere with cAMP signaling pathways in living cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Physiological and Molecular Effects of the Cyclic Nucleotides cAMP and cGMP on Arabidopsis thaliana

    KAUST Repository

    Herrera, Natalia M.

    2012-12-01

    The cyclic nucleotide monophosphates (CNs), cAMP and cGMP, are second messengers that participate in the regulation of development, metabolism and adaptive responses. In plants, CNs are associated with the control of pathogen responses, pollen tube orientation, abiotic stress response, membrane transport regulation, stomatal movement and light perception. In this study, we hypothesize that cAMP and cGMP promote changes in the transcription level of genes related to photosynthesis, high light and membrane transport in Arabidopsis thaliana leaves and, that these changes at the molecular level can have functional biological consequences. For this reason we tested if CNs modulate the photosynthetic rate, responses to high light and root ion transport. Real time quantitative PCR was used to assess transcription levels of selected genes and infrared gas analyzers coupled to fluorescence sensors were used to measure the photosynthetic parameters. We present evidence that both cAMP and cGMP modulate foliar mRNA levels early after stimulation. The two CNs trigger different responses indicating that the signals have specificity. A comparison of proteomic and transcriptional changes suggest that both transcriptional and post-transcriptional mechanisms are modulated by CNs. cGMP up-regulates the mRNA levels of components of the photosynthesis and carbon metabolism. However, neither cAMP nor cGMP trigger differences in the rate of carbon assimilation, maximum efficiency of the photosystem II (PSII), or PSII operating efficiency. It was also demonstrated that CN regulate the expression of its own targets, the cyclic nucleotide gated channels - CNGC. Further studies are needed to identify the components of the signaling transduction pathway that mediate cellular changes and their respective regulatory and/or signaling roles.

  6. Interaction of renin-angiotensin system and adenosine monophosphate-activated protein kinase signaling pathway in renal carcinogenesis of uninephrectomized rats.

    Science.gov (United States)

    Yang, Ke-Ke; Sui, Yi; Zhou, Hui-Rong; Zhao, Hai-Lu

    2017-05-01

    Renin-angiotensin system and adenosine monophosphate-activated protein kinase signaling pathway both play important roles in carcinogenesis, but the interplay of renin-angiotensin system and adenosine monophosphate-activated protein kinase in carcinogenesis is not clear. In this study, we researched the interaction of renin-angiotensin system and adenosine monophosphate-activated protein kinase in renal carcinogenesis of uninephrectomized rats. A total of 96 rats were stratified into four groups: sham, uninephrectomized, and uninephrectomized treated with angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. Renal adenosine monophosphate-activated protein kinase and its downstream molecule acetyl coenzyme A carboxylase were detected by immunohistochemistry and western blot at 10 months after uninephrectomy. Meanwhile, we examined renal carcinogenesis by histological transformation and expressions of Ki67 and mutant p53. During the study, fasting lipid profiles were detected dynamically at 3, 6, 8, and 10 months. The results indicated that adenosine monophosphate-activated protein kinase expression in uninephrectomized rats showed 36.8% reduction by immunohistochemistry and 89.73% reduction by western blot. Inversely, acetyl coenzyme A carboxylase expression increased 83.3% and 19.07% in parallel to hyperlipidemia at 6, 8, and 10 months. The histopathology of carcinogenesis in remnant kidneys was manifested by atypical proliferation and carcinoma in situ, as well as increased expressions of Ki67 and mutant p53. Intervention with angiotensin-converting enzyme inhibitor or angiotensin receptor blocker significantly prevented the inhibition of adenosine monophosphate-activated protein kinase signaling pathway and renal carcinogenesis in uninephrectomized rats. In conclusion, the novel findings suggest that uninephrectomy-induced disturbance in adenosine monophosphate-activated protein kinase signaling pathway resulted in hyperlipidemia and

  7. A cyclic GMP signalling module that regulates gliding motility in a malaria parasite.

    Directory of Open Access Journals (Sweden)

    Robert W Moon

    2009-09-01

    Full Text Available The ookinete is a motile stage in the malaria life cycle which forms in the mosquito blood meal from the zygote. Ookinetes use an acto-myosin motor to glide towards and penetrate the midgut wall to establish infection in the vector. The regulation of gliding motility is poorly understood. Through genetic interaction studies we here describe a signalling module that identifies guanosine 3', 5'-cyclic monophosphate (cGMP as an important second messenger regulating ookinete differentiation and motility. In ookinetes lacking the cyclic nucleotide degrading phosphodiesterase delta (PDEdelta, unregulated signalling through cGMP results in rounding up of the normally banana-shaped cells. This phenotype is suppressed in a double mutant additionally lacking guanylyl cyclase beta (GCbeta, showing that in ookinetes GCbeta is an important source for cGMP, and that PDEdelta is the relevant cGMP degrading enzyme. Inhibition of the cGMP-dependent protein kinase, PKG, blocks gliding, whereas enhanced signalling through cGMP restores normal gliding speed in a mutant lacking calcium dependent protein kinase 3, suggesting at least a partial overlap between calcium and cGMP dependent pathways. These data demonstrate an important function for signalling through cGMP, and most likely PKG, in dynamically regulating ookinete gliding during the transmission of malaria to the mosquito.

  8. Post-translational Analysis of Arabidopsis thaliana Proteins in Response to Cyclic Guanosine Monophosphate Treatment

    KAUST Repository

    Parrott, Brian

    2011-12-12

    The introduction of mass spectrometry techniques to the field of biology has made possible the exploration of the proteome as a whole system as opposed to prior techniques, such as anti-body based assays or yeast two-hybrid studies, which were strictly limited to the study of a few proteins at a time. This practice has allowed for a systems biology approach of exploring the proteome, with the possibility of viewing entire pathways over increments of time. In this study, the effect of treating Arabidopsis thaliana suspension culture cells with 3’,5’-cyclic guanosine monophosphate (cGMP), which is a native second messenger, was examined. Samples were collected at four time points and proteins were extracted and enriched for both oxidation and phosphorylation before analysis via mass spectrometry. Preliminary results suggest a tendency towards an increased number of phosphorylated proteins as a result of cGMP treatment. The data also showed a sharp increase in methionine oxidation in response to the treatment, occurring within the first ten minutes. This finding suggests that cGMP may utilize methionine oxidation as a mechanism of signal transduction. As such, this study corroborates a growing body of evidence supporting the inclusion of methionine oxidation in intracellular signaling pathways.

  9. Partial reconstitution of photoreceptor cGMP phosphodiesterase characteristics in cGMP phosphodiesterase-5.

    Science.gov (United States)

    Granovsky, A E; Artemyev, N O

    2001-06-15

    Photoreceptor cGMP phosphodiesterases (PDE6) are uniquely qualified to serve as effector enzymes in the vertebrate visual transduction cascade. In the dark-adapted photoreceptors, the activity of PDE6 is blocked via tight association with the inhibitory gamma-subunits (Pgamma). The Pgamma block is removed in the light-activated PDE6 by the visual G protein, transducin. Transducin-activated PDE6 exhibits an exceptionally high catalytic rate of cGMP hydrolysis ensuring high signal amplification. To identify the structural determinants for the inhibitory interaction with Pgamma and the remarkable cGMP hydrolytic ability, we sought to reproduce the PDE6 characteristics by mutagenesis of PDE5, a related cyclic GMP-specific, cGMP-binding PDE. PDE5 is insensitive to Pgamma and has a more than 100-fold lower k(cat) for cGMP hydrolysis. Our mutational analysis of chimeric PDE5/PDE6alpha' enzymes revealed that the inhibitory interaction of cone PDE6 catalytic subunits (PDE6alpha') with Pgamma is mediated primarily by three hydrophobic residues at the entry to the catalytic pocket, Met(758), Phe(777), and Phe(781). The maximal catalytic rate of PDE5 was enhanced by at least 10-fold with substitutions of PDE6alpha'-specific glycine residues for the corresponding PDE5 alanine residues, Ala(608) and Ala(612). The Gly residues are adjacent to the highly conserved metal binding motif His-Asn-X-X-His, which is essential for cGMP hydrolysis. Our results suggest that the unique Gly residues allow the PDE6 metal binding site to adopt a more favorable conformation for cGMP hydrolysis.

  10. Cyclic Nucleotide Signalling in Kidney Fibrosis

    Directory of Open Access Journals (Sweden)

    Elisabeth Schinner

    2015-01-01

    Full Text Available Kidney fibrosis is an important factor for the progression of kidney diseases, e.g., diabetes mellitus induced kidney failure, glomerulosclerosis and nephritis resulting in chronic kidney disease or end-stage renal disease. Cyclic adenosine monophosphate (cAMP and cyclic guanosine monophosphate (cGMP were implicated to suppress several of the above mentioned renal diseases. In this review article, identified effects and mechanisms of cGMP and cAMP regarding renal fibrosis are summarized. These mechanisms include several signalling pathways of nitric oxide/ANP/guanylyl cyclases/cGMP-dependent protein kinase and cAMP/Epac/adenylyl cyclases/cAMP-dependent protein kinase. Furthermore, diverse possible drugs activating these pathways are discussed. From these diverse mechanisms it is expected that new pharmacological treatments will evolve for the therapy or even prevention of kidney failure.

  11. Hyperactivity and memory/learning deficits evoked by developmental exposure to nicotine and/or ethanol are mitigated by cAMP and cGMP signaling cascades activation.

    Science.gov (United States)

    Abreu-Villaça, Yael; Carvalho-Graça, Anna C; Skinner, Gabriela; Lotufo, Bruna M; Duarte-Pinheiro, Vitor H S; Ribeiro-Carvalho, Anderson; Manhães, Alex C; Filgueiras, Claudio C

    2018-04-10

    Pregnant smoking women are frequently episodic drinkers. Here, we investigated whether ethanol exposure restricted to the brain growth spurt period when combined with chronic developmental exposure to nicotine aggravates memory/learning deficits and hyperactivity, and associated cAMP and cGMP signaling disruption. To further investigate the role of these signaling cascades, we verified whether vinpocetine (a phosphodiesterase inhibitor) ameliorates the neurochemical and behavioral outcomes. Swiss mice had free access to nicotine (NIC, 50 μg/ml) or water to drink during gestation and until the 8th postnatal day (PN8). Ethanol (ETOH, 5 g/kg, i.p.) or saline were injected in the pups every other day from PN2 to PN8. At PN30, animals either received vinpocetine (20 mg/kg, i.p.) or vehicle before being tested in the step-down passive avoidance or open field. Memory/learning was impaired in NIC, ETOH and NIC + ETOH mice, and vinpocetine mitigated ETOH- and NIC + ETOH-induced deficits. Locomotor hyperactivity identified in ETOH and NIC + ETOH mice was ameliorated by vinpocetine. While cyclic nucleotides levels in cerebral cortex and hippocampus were reduced by NIC, ETOH and NIC + ETOH, this outcome was more consistent in the latter group. As observed for behavior, vinpocetine normalized NIC + ETOH nucleotides levels. pCREB levels were also increased in response to vinpocetine, with stronger effects in the NIC + ETOH group. Exposure to both drugs of abuse worsens behavioral and neurochemical disruption. These findings and the amelioration of deleterious effects by vinpocetine support the idea that cAMP and cGMP signaling contribute to nicotine- and ethanol-induced hyperactivity and memory/learning deficits. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Modulation of cGMP by human HO-1 retrovirus gene transfer in pulmonary microvessel endothelial cells.

    Science.gov (United States)

    Abraham, Nader G; Quan, Shuo; Mieyal, Paul A; Yang, Liming; Burke-Wolin, Theresa; Mingone, Christopher J; Goodman, Alvin I; Nasjletti, Alberto; Wolin, Michael S

    2002-11-01

    Carbon monoxide (CO) stimulates guanylate cyclase (GC) and increases guanosine 3',5'-cyclic monophosphate (cGMP) levels. We transfected rat-lung pulmonary endothelial cells with a retrovirus-mediated human heme oxygenase (hHO)-1 gene. Pulmonary cells that expressed hHO-1 exhibited a fourfold increase in HO activity associated with decreases in the steady-state levels of heme and cGMP without changes in soluble GC (sGC) and endothelial nitric oxide synthase (NOS) proteins or basal nitrite production. Heme elicited significant increases in CO production and intracellular cGMP levels in both pulmonary endothelial and pulmonary hHO-1-expressing cells. N(omega)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOS, significantly decreased cGMP levels in heme-treated pulmonary endothelial cells but not heme-treated hHO-1-expressing cells. In the presence of exogenous heme, CO and cGMP levels in hHO-1-expressing cells exceeded the corresponding levels in pulmonary endothelial cells. Acute exposure of endothelial cells to SnCl2, which is an inducer of HO-1, increased cGMP levels, whereas chronic exposure decreased heme and cGMP levels. These results indicate that prolonged overexpression of HO-1 ultimately decreases sGC activity by limiting the availability of cellular heme. Heme activates sGC and enhances cGMP levels via a mechanism that is largely insensitive to NOS inhibition.

  13. Cyclic 3',5'-adenosine monophosphate (cAMP) signaling in the anterior pituitary gland in health and disease.

    Science.gov (United States)

    Hernández-Ramírez, Laura C; Trivellin, Giampaolo; Stratakis, Constantine A

    2018-03-05

    The cyclic 3',5'-adenosine monophosphate (cAMP) was the first among the so-called "second messengers" to be described. It is conserved in most organisms and functions as a signal transducer by mediating the intracellular effects of multiple hormones and neurotransmitters. In this review, we first delineate how different members of the cAMP pathway ensure its correct compartmentalization and activity, mediate the terminal intracellular effects, and allow the crosstalk with other signaling pathways. We then focus on the pituitary gland, where cAMP exerts a crucial function by controlling the responsiveness of the cells to hypothalamic hormones, neurotransmitters and peripheral factors. We discuss the most relevant physiological functions mediated by cAMP in the different pituitary cell types, and summarize the defects affecting this pathway that have been reported in the literature. We finally discuss how a deregulated cAMP pathway is involved in the pathogenesis of pituitary disorders and how it affects the response to therapy. Copyright © 2017. Published by Elsevier B.V.

  14. The role of cGMP hydrolysing phosphodiesterases 1 and 5 in cerebral artery dilatation

    DEFF Research Database (Denmark)

    Kruuse, Christina; Rybalkin, S D; Khurana, T S

    2001-01-01

    The aim was to investigate the presence and activity of cGMP hydrolysing phosphodiesterases in guinea pig basilar arteries and the effect of selective and non-selective phosphodiesterase inhibitors on cerebral artery dilatation involving the nitric oxide (NO)-guanosine cyclic 3'5-monophosphate (cGMP...... a close relation to the nitric oxide-cGMP pathway. The responses to zaprinast and dipyridamole, however, were not only moderately affected, but also restored by sodium nitroprusside (0.1 microM) pretreatment. At high concentrations, the dilatory effects of zaprinast and dipyridamole were partly caused...... by cGMP-independent mechanisms. Targeting the phosphodiesterases present in cerebral arteries, with selective inhibitors or activators of phosphodiesterase, may be a possible new way of treating cerebrovascular disease....

  15. The potent, indirect adenosine monophosphate-activated protein kinase activator R419 attenuates mitogen-activated protein kinase signaling, inhibits nociceptor excitability, and reduces pain hypersensitivity in mice

    Directory of Open Access Journals (Sweden)

    Galo L. Mejia

    2016-07-01

    Full Text Available Abstract. There is a great need for new therapeutics for the treatment of pain. A possible avenue to development of such therapeutics is to interfere with signaling pathways engaged in peripheral nociceptors that cause these neurons to become hyperexcitable. There is strong evidence that mitogen-activated protein kinases and phosphoinositide 3-kinase (PI3K/mechanistic target of rapamycin signaling pathways are key modulators of nociceptor excitability in vitro and in vivo. Activation of adenosine monophosphate-activated protein kinase (AMPK can inhibit signaling in both of these pathways, and AMPK activators have been shown to inhibit nociceptor excitability and pain hypersensitivity in rodents. R419 is one of, if not the most potent AMPK activator described to date. We tested whether R419 activates AMPK in dorsal root ganglion (DRG neurons and if this leads to decreased pain hypersensitivity in mice. We find that R419 activates AMPK in DRG neurons resulting in decreased mitogen-activated protein kinase signaling, decreased nascent protein synthesis, and enhanced P body formation. R419 attenuates nerve growth factor (NGF-induced changes in excitability in DRG neurons and blocks NGF-induced mechanical pain amplification in vivo. Moreover, locally applied R419 attenuates pain hypersensitivity in a model of postsurgical pain and blocks the development of hyperalgesic priming in response to both NGF and incision. We conclude that R419 is a promising lead candidate compound for the development of potent and specific AMPK activation to inhibit pain hypersensitivity as a result of injury.

  16. Role of adenosine 5'-monophosphate-activated protein kinase subunits in skeletal muscle mammalian target of rapamycin signaling

    DEFF Research Database (Denmark)

    Deshmukh, Atul S.; Treebak, Jonas Thue; Long, Yun Chau

    2008-01-01

    AMP-activated protein kinase (AMPK) is an important energy-sensing protein in skeletal muscle. Mammalian target of rapamycin (mTOR) mediates translation initiation and protein synthesis through ribosomal S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1). AMPK...... activation reduces muscle protein synthesis by down-regulating mTOR signaling, whereas insulin mediates mTOR signaling via Akt activation. We hypothesized that AMPK-mediated inhibitory effects on mTOR signaling depend on catalytic alpha2 and regulatory gamma3 subunits. Extensor digitorum longus muscle from...... (Thr37/46) (P mTOR targets, suggesting mTOR signaling is blocked by prior AMPK activation. The AICAR-induced inhibition was partly rescued...

  17. Cyclic guanosine monophosphate in the regulation of the cell function

    Directory of Open Access Journals (Sweden)

    Małgorzata Zbrojkiewicz

    2016-12-01

    Full Text Available Intracellular concentration of cGMP depends on the activity of guanylate cyclase, responsible for its synthesis, on the activity of cyclic nucleotide degrading enzymes - phosphodiesterases (PDEs. There are two forms of guanylate cyclase: the membrane-bound cyclase and the soluble form. The physiological activators of the membrane guanylate cyclase are natriuretic peptides (NPs, and of the cytosolic guanylate cyclase - nitric oxide (NO and carbon monoxide (CO. Intracellular cGMP signaling pathways arise from its direct effect on the activity of G protein kinases, phosphodiesterases and cyclic nucleotide dependent cation channels. It has been shown in recent years that cGMP can also affect other signal pathways in cell signaling activity involving Wnt proteins and sex hormones. The increased interest in the research on the role of cGMP, resulted also in the discovery of its role in the regulation of phototransduction in the eye, neurotransmission, calcium homeostasis, platelet aggregation, heartbeat, bone remodeling, lipid metabolism and the activity of the cation channels. Better understanding of the mechanisms of action of cGMP in the regulation of cell function can create new opportunities for the cGMP affecting drugs use in the pharmacotherapy.

  18. A novel Ras-interacting protein required for chemotaxis and cyclic adenosine monophosphate signal relay in Dictyostelium.

    Science.gov (United States)

    Lee, S; Parent, C A; Insall, R; Firtel, R A

    1999-09-01

    We have identified a novel Ras-interacting protein from Dictyostelium, RIP3, whose function is required for both chemotaxis and the synthesis and relay of the cyclic AMP (cAMP) chemoattractant signal. rip3 null cells are unable to aggregate and lack receptor activation of adenylyl cyclase but are able, in response to cAMP, to induce aggregation-stage, postaggregative, and cell-type-specific gene expression in suspension culture. In addition, rip3 null cells are unable to properly polarize in a cAMP gradient and chemotaxis is highly impaired. We demonstrate that cAMP stimulation of guanylyl cyclase, which is required for chemotaxis, is reduced approximately 60% in rip3 null cells. This reduced activation of guanylyl cyclase may account, in part, for the defect in chemotaxis. When cells are pulsed with cAMP for 5 h to mimic the endogenous cAMP oscillations that occur in wild-type strains, the cells will form aggregates, most of which, however, arrest at the mound stage. Unlike the response seen in wild-type strains, the rip3 null cell aggregates that form under these experimental conditions are very small, which is probably due to the rip3 null cell chemotaxis defect. Many of the phenotypes of the rip3 null cell, including the inability to activate adenylyl cyclase in response to cAMP and defects in chemotaxis, are very similar to those of strains carrying a disruption of the gene encoding the putative Ras exchange factor AleA. We demonstrate that aleA null cells also exhibit a defect in cAMP-mediated activation of guanylyl cyclase similar to that of rip3 null cells. A double-knockout mutant (rip3/aleA null cells) exhibits a further reduction in receptor activation of guanylyl cyclase, and these cells display almost no cell polarization or movement in cAMP gradients. As RIP3 preferentially interacts with an activated form of the Dictyostelium Ras protein RasG, which itself is important for cell movement, we propose that RIP3 and AleA are components of a Ras

  19. Leptin interferes with 3',5'-Cyclic Adenosine Monophosphate (cAMP signaling to inhibit steroidogenesis in human granulosa cells

    Directory of Open Access Journals (Sweden)

    HoYuen Basil

    2009-10-01

    Full Text Available Abstract Background Obesity has been linked to an increased risk of female infertility. Leptin, an adipocytokine which is elevated during obesity, may influence gonadal function through modulating steroidogenesis in granulosa cells. Methods The effect of leptin on progesterone production in simian virus 40 immortalized granulosa (SVOG cells was examined by Enzyme linked immunosorbent assay (ELISA. The effect of leptin on the expression of the steroidogenic enzymes (StAR, P450scc, 3betaHSD in SVOG cells was examined by real-time PCR and Western blotting. The mRNA expression of leptin receptor isoforms in SVOG cells were examined by using PCR. SVOG cells were co-treated with leptin and specific pharmacological inhibitors to identify the signaling pathways involved in leptin-reduced progesterone production. Silencing RNA against leptin receptor was used to determine that the inhibition of leptin on cAMP-induced steroidogenesis acts in a leptin receptor-dependent manner. Results and Conclusion In the present study, we investigated the cellular mechanisms underlying leptin-regulated steroidogenesis in human granulosa cells. We show that leptin inhibits 8-bromo cAMP-stimulated progesterone production in a concentration-dependent manner. Furthermore, we show that leptin inhibits expression of the cAMP-stimulated steroidogenic acute regulatory (StAR protein, the rate limiting de novo protein in progesterone synthesis. Leptin induces the activation of ERK1/2, p38 and JNK but only the ERK1/2 (PD98059 and p38 (SB203580 inhibitors attenuate the leptin-induced inhibition of cAMP-stimulated StAR protein expression and progesterone production. These data suggest that the leptin-induced MAPK signal transduction pathway interferes with cAMP/PKA-stimulated steroidogenesis in human granulosa cells. Moreover, siRNA mediated knock-down of the endogenous leptin receptor attenuates the effect of leptin on cAMP-induced StAR protein expression and progesterone

  20. CSF concentrations of cAMP and cGMP are lower in patients with Creutzfeldt-Jakob disease but not Parkinson's disease and amyotrophic lateral sclerosis.

    Directory of Open Access Journals (Sweden)

    Patrick Oeckl

    Full Text Available BACKGROUND: The cyclic nucleotides cyclic adenosine-3',5'-monophosphate (cAMP and cyclic guanosine-3',5'-monophosphate (cGMP are important second messengers and are potential biomarkers for Parkinson's disease (PD, amyotrophic lateral sclerosis (ALS and Creutzfeldt-Jakob disease (CJD. METHODOLOGY/PRINCIPAL FINDINGS: Here, we investigated by liquid chromatography/tandem mass spectrometry (LC-MS/MS the cerebrospinal fluid (CSF concentrations of cAMP and cGMP of 82 patients and evaluated their diagnostic potency as biomarkers. For comparison with a well-accepted biomarker, we measured tau concentrations in CSF of CJD and control patients. CJD patients (n = 15 had lower cAMP (-70% and cGMP (-55% concentrations in CSF compared with controls (n = 11. There was no difference in PD, PD dementia (PDD and ALS cases. Receiver operating characteristic (ROC curve analyses confirmed cAMP and cGMP as valuable diagnostic markers for CJD indicated by the area under the curve (AUC of 0.86 (cAMP and 0.85 (cGMP. We calculated a sensitivity of 100% and specificity of 64% for cAMP and a sensitivity of 67% and specificity of 100% for cGMP. The combination of both nucleotides increased the sensitivity to 80% and specificity to 91% for the term cAMPxcGMP (AUC 0.92 and to 93% and 100% for the ratio tau/cAMP (AUC 0.99. CONCLUSIONS/SIGNIFICANCE: We conclude that the CSF determination of cAMP and cGMP may easily be included in the diagnosis of CJD and could be helpful in monitoring disease progression as well as in therapy control.

  1. Biophysical Techniques for Detection of cAMP and cGMP in Living Cells

    Directory of Open Access Journals (Sweden)

    Viacheslav O. Nikolaev

    2013-04-01

    Full Text Available Cyclic nucleotides cAMP and cGMP are ubiquitous second messengers which regulate myriads of functions in virtually all eukaryotic cells. Their intracellular effects are often mediated via discrete subcellular signaling microdomains. In this review, we will discuss state-of-the-art techniques to measure cAMP and cGMP in biological samples with a particular focus on live cell imaging approaches, which allow their detection with high temporal and spatial resolution in living cells and tissues. Finally, we will describe how these techniques can be applied to the analysis of second messenger dynamics in subcellular signaling microdomains.

  2. Auxin-induced nitric oxide, cGMP and gibberellins were involved in the gravitropism

    Science.gov (United States)

    Cai, Weiming; Hu, Liwei; Hu, Xiangyang; Cui, Dayong; Cai, Weiming

    Gravitropism is the asymmetric growth or curvature of plant organs in response to gravistimulation. There is a complex signal transduction cascade which involved in the differential growth of plants in response to changes in the gravity vector. The role of auxin in gravitropism has been demonstrated by many experiments, but little is known regarding the molecular details of such effects. In our studies before, mediation of the gravitropic bending of soybean roots and rice leaf sheath bases by nitric oxide, cGMP and gibberellins, are induced by auxin. The asymmetrical distribution of nitric oxide, cGMP and gibberellins resulted from the asymmetrical synthesis of them in bending sites. In soybean roots, inhibitions of NO and cGMP synthesis reduced differential NO and cGMP accumulation respectively, which both of these effects can lead to the reduction of gravitropic bending. Gibberellin-induced OsXET, OsEXPA4 and OsRWC3 were also found involved in the gravitropic bending. These data indicated that auxin-induced nitric oxide, cGMP and gibberellins were involved in the gravitropism. More experiments need to prove the more detailed mechanism of them.

  3. Novel water-soluble curcumin derivative mediating erectile signaling.

    Science.gov (United States)

    Abdel Aziz, Mohamed Talaat; El Asmer, Mohammed F; Rezq, Ameen; Kumosani, Taha Abdullah; Mostafa, Samya; Mostafa, Taymour; Atta, Hazem; Abdel Aziz Wassef, Mohamed; Fouad, Hanan H; Rashed, Laila; Sabry, Dina; Hassouna, Amira A; Senbel, Amira; Abdel Aziz, Ahmed

    2010-08-01

    Curcumin is an inducer of heme oxygenase enzyme-1 (HO-1) that is involved in erectile signaling via elevating cyclic guanosine monophosphate (cGMP)levels. To assess the effect of oral administration of a water-soluble long-acting curcumin derivative on erectile signaling. Two hundred and thirty six male white albino rats were divided into four groups; group 1 (N = 20) includes control. Group 2 (N = 72) was equally divided into four subgroups; subgroup 1 received pure curcumin (10 mg/kg), subgroup 2 received the long-acting curcumin derivative (2 mg/kg), subgroup 3 received the long-acting curcumin derivative (10 mg/kg), and subgroup 4 received sildenafil (4 mg/kg). Subgroups were sacrificed after the first, second, and third hour. Group 3 (N = 72) was equally divided into the same four subgroups already mentioned and were sacrificed after 24 hours, 48 hours, and 1 week. Group 4 (N = 72) was subjected to intracavernosal pressure (ICP) measurements 1 hour following oral administration of the same previous doses in the same rat subgroups. Cavernous tissue HO enzyme activity, cGMP, and ICP. In group 2, there was a significant progressive maintained elevation of HO activity and cGMP tissue levels starting from the first hour in subgroups 3 and 4, whereas, the rise in HO activity and cGMP started from second hour regarding the other rat subgroups. Sildenafil effect decreased after 3 hours. In group 3, there was a significant maintained elevation of HO activity and cGMP tissue levels extended to 1 week as compared to controls for all rat subgroups that received both forms of curcumin. In group 4, long-acting curcumin derivative exhibited more significant potentiation of intracavernosal pressure as compared to control and to the pure curcumin. Water-soluble long-acting curcumin derivative could mediate erectile function via upregulating cavernous tissue cGMP. © 2009 International Society for Sexual Medicine.

  4. Effects of Biotin Supplementation in the Diet on Adipose Tissue cGMP Concentrations, AMPK Activation, Lipolysis, and Serum-Free Fatty Acid Levels.

    Science.gov (United States)

    Boone-Villa, Daniel; Aguilera-Méndez, Asdrubal; Miranda-Cervantes, Adriana; Fernandez-Mejia, Cristina

    2015-10-01

    Several studies have shown that pharmacological concentrations of biotin decrease hyperlipidemia. The molecular mechanisms by which pharmacological concentrations of biotin modify lipid metabolism are largely unknown. Adipose tissue plays a central role in lipid homeostasis. In the present study, we analyzed the effects of biotin supplementation in adipose tissue on signaling pathways and critical proteins that regulate lipid metabolism, as well as on lipolysis. In addition, we assessed serum fatty acid concentrations. Male BALB/cAnN Hsd mice were fed a control or a biotin-supplemented diet (control: 1.76 mg biotin/kg; supplemented: 97.7 mg biotin/kg diet) over 8 weeks postweaning. Compared with the control group, biotin-supplemented mice showed an increase in the levels of adipose guanosine 3',5'-cyclic monophosphate (cGMP) (control: 30.3±3.27 pmol/g wet tissue; supplemented: 49.5±3.44 pmol/g wet tissue) and of phosphorylated forms of adenosine 5'-monophosphate-activated protein kinase (AMPK; 65.2%±1.06%), acetyl-coenzyme A (CoA), carboxylase-1 (196%±68%), and acetyl-CoA carboxylase-2 (78.1%±18%). Serum fatty acid concentrations were decreased (control: 1.12±0.04 mM; supplemented: 0.91±0.03 mM), and no change in lipolysis was found (control: 0.29±0.05 μmol/mL; supplemented: 0.33±0.08 μmol/mL). In conclusion, 8 weeks of dietary biotin supplementation increased adipose tissue cGMP content and protein expression of the active form of AMPK and of the inactive forms of acetyl-CoA carboxylase-1 and acetyl-CoA carboxylase-2. Serum fatty acid levels fell, and no change in lipolysis was observed. These findings provide insight into the effects of biotin supplementation on adipose tissue and support its use in the treatment of dyslipidemia.

  5. Beneficial effects of combined benazepril-amlodipine on cardiac nitric oxide, cGMP, and TNF-alpha production after cardiac ischemia.

    Science.gov (United States)

    Siragy, Helmy M; Xue, Chun; Webb, Randy L

    2006-05-01

    The aim of this study was to determine if myocardial inflammation is increased after myocardial ischemia and whether angiotensin-converting enzyme inhibitors, calcium channel blockers, or diuretics decrease mediators of inflammation in rats with induced myocardial ischemia. Changes in cardiac interstitial fluid (CIF) levels of nitric oxide metabolites (NOX), cyclic guanosine 3',5'-monophosphate (cGMP), angiotensin II (Ang II), and tumor necrosis factor-alpha (TNF-alpha) were monitored with/without oral administration of benazepril, amlodipine, combined benazepril-amlodipine, or hydrochlorothiazide. Using a microdialysis technique, levels of several mediators of inflammation were measured after sham operation or 30-minute occlusion of the left anterior descending coronary artery. Compared with sham animals, levels of CIF NOX and cGMP were decreased in animals with ischemia (P Benazepril or amlodipine significantly increased NOX levels (P benazepril significantly increased cGMP (P benazepril-amlodipine further increased CIF NOX and cGMP (P benazepril alone, or combined benazepril-amlodipine significantly reduced TNF-alpha (P benazepril-amlodipine may be beneficial for managing cardiac ischemia.

  6. Kinetics of hydrogen-deuterium exchange in guanosine 5'-monophosphate and guanosine 3':5'-monophosphate determined by laser-Raman spectroscopy.

    Science.gov (United States)

    Lane, M J; Thomas, G J

    1979-09-04

    Pseudo-first-order rate constants governing the deuterium exchange of 8-CH groups in guanosine 5'-monophosphate (5'-rGMP) and guanosine 3':5'-monophosphate (cGMP) were determined as a function of temperature in the range 30-80 degrees C by means of laser-Raman spectroscopy. For each guanine nucleotide the logarithm of the rate constant exhibits a strictly linear dependence on reciprocal temperature: i.e., k psi = Ae-Ea/RT with A = 8.84 X 10(14) h-1 and Ea = 24.6 kcal/mol for 5'-rGMP and A = 3.33 X 10(13) h-1 and Ea = 22.2 kcal/mol for cGMP. Exchange of the 8-CH groups in guanine nucleotides is generally 2-3 times more rapid than in adenine nucleotides [cf. g. j. thomas, Jr., & J. Livramento (1975) Biochemistry 14, 5210-5218]. As in the case of adenine nucleotides, cyclic and 5' nucleotides of guanine exchange at markedly different rates at lower temperatures, with exchange in the cyclic nucleotide being the more facile. Each of the guanine nucleotides was prepared in four different isotopic modifications for Raman spectral analysis. The Raman frequency shifts resulting from the various isotopic substitutions have been tabulated, and assignments have been given for most of the observed vibrational frequencies.

  7. IL-4 induces cAMP and cGMP in human monocytic cells

    Directory of Open Access Journals (Sweden)

    B. Dugas

    1995-01-01

    Full Text Available Human monocytes, preincubated with IFN-γ respond to IL-4 by a cGMP increase through activation of an inducible NO synthase. Here, IL-4 was found to induce an accumulation of cGMP (1 – 3 min and cAMP (20 – 25 min in unstimulated monocytes. This was impaired with NOS inhibitors, but also with EGTA and calcium/calmodulin inhibitors. These results suggest that: (1 IL-4 may stimulate different NOS isoforms in resting and IFN-γ activated monocytes, and (2 cAMP accumulation may be partially dependent on the NO pathway. By RT-PCR, a type III constitutive NOS mRNA was detected in U937 monocytic cells. IL-4 also increased the [Ca2+]i in these cells. Different NOS may thus be expressed in monocytic cells depending on their differentiation and the signals they receive.

  8. Aging has the opposite effect on cAMP and cGMP circadian variations in rat Leydig cells.

    Science.gov (United States)

    Baburski, Aleksandar Z; Sokanovic, Srdjan J; Andric, Silvana A; Kostic, Tatjana S

    2017-05-01

    The Leydig cell physiology displays a circadian rhythm driven by a complex interaction of the reproductive axis hormones and circadian system. The final output of this regulatory process is circadian pattern of steroidogenic genes expression and testosterone production. Aging gradually decreases robustness of rhythmic testosterone secretion without change in pattern of LH secretion. Here, we analyzed effect of aging on circadian variation of cAMP and cGMP signaling in Leydig cells. Results showed opposite effect of aging on cAMP and cGMP daily variation. Reduced amplitude of cAMP circadian oscillation was probably associated with changed expression of genes involved in cAMP production (increased circadian pattern of Adcy7, Adcy9, Adcy10 and decreased Adcy3); cAMP degradation (increased Pde4a, decreased Pde8b, canceled rhythm of Pde4d, completely reversed circadian pattern of Pde7b and Pde8a); and circadian expression of protein kinase A subunits (Prkac/PRKAC and Prkar2a). Aging stimulates expression of genes responsible for cGMP production (Nos2, Gucy1a3 and Gucy1b3/GUCYB3) and degradation (Pde5a, Pde6a and Pde6h) but the overall net effect is elevation of cGMP circadian oscillations in Leydig cells. In addition, the expression of cGMP-dependent kinase, Prkg1/PRKG1 is up-regulated. It seems that aging potentiate cGMP- and reduce cAMP-signaling in Leydig cells. Since both signaling pathways affect testosterone production and clockwork in the cells, further insights into these signaling pathways will help to unravel disorders linked to the circadian timing system, aging and reproduction.

  9. [Effect of twirling-reinforcing-reducing needling manipulations on contents of serum acetylcholine and arterial NOS and cGMP in stress-induced hypertension rats].

    Science.gov (United States)

    Liu, Wei; Zhu, Ling-Qun; Chen, Si-Si; Lu, Shu-Chao; Tang, Jie; Liu, Qing-Guo

    2015-04-01

    To observe the effect of twirling-reinforcing or reducing needling manipulations on plasma acetylcholine (Ach) content and expression of nitric oxide synthetase (NOS) and cyclic guanosine monophosphate (cGMP) in thoracic artery tissue in stress-induced hypertension rats. A total of 60 male rats were randomly divided into blank control, model, acupuncture (no-needle-manipulation) , twirling-reinforcing needling and twirling-reducing needling groups (n = 12 in each group). The stress hypertension model was established by giving the animals with noise and electric shock stimulation (paw), twice a day for 15 days. Acupuncture stimulation was applied to bilateral "Taichong" (LR 3) for 1 min, followed by retaining the needles for 20 min. The treatment was conducted once daily for 7 days. Systolic blood pressure of the rat's tail was detected with non-invasive method and plasma Ach, and NOS and cGMP contents in the thoracic artery tissue were measured using ELISA method. Compared with the control group, the systolic blood pressure was significantly higher in the model group after 15 days' stress stimulation (P arterial NOS and cGMP were markedly down-regulated (P arterial cGMP content was found in the no-needle-manipulation group (P > 0.05). The effect of the twirling-reducing needling was superior to that of no-needle-manipulation and twirling-reinforcing needling in lowering blood pressure and raising plasma Ach content (P hypertensive effect in stress hypertension rats, which may be associated with its effects in raising blood Ach, and arterial NOS and cGMP levels.

  10. Short-term dehydroepiandrosterone treatment increases platelet cGMP production in elderly male subjects.

    Science.gov (United States)

    Martina, Valentino; Benso, Andrea; Gigliardi, Valentina Ramella; Masha, Andi; Origlia, Carla; Granata, Riccarda; Ghigo, Ezio

    2006-03-01

    Several clinical and population-based studies suggest that dehydroepiandrosterone (DHEA) and its sulphate (DHEA-S) play a protective role against atherosclerosis and coronary artery disease in human. However, the mechanisms underlying this action are still unknown. It has recently been suggested that DHEA-S could delay atheroma formation through an increase in nitric oxide (NO) production. Twenty-four aged male subjects [age (mean +/- SEM): 65.4 +/- 0.7 year; range: 58.2-67.6 years] underwent a blinded placebo controlled study receiving DHEA (50 mg p.o. daily at bedtime) or placebo for 2 months. Platelet cyclic guanosine-monophosphate (cGMP) concentration (as marker of NO production) and serum levels of DHEA-S, DHEA, IGF-I, insulin, glucose, oestradiol (E(2)), testosterone, plasminogen activator inhibitor (PAI)-1 antigen (PAI-1 Ag), homocysteine and lipid profile were evaluated before and after the 2-month treatment with DHEA or placebo. At the baseline, all variables in the two groups were overlapping. All parameters were unchanged after treatment with placebo. Conversely, treatment with DHEA (a) increased (P < 0.001 vs. baseline) platelet cGMP (111.9 +/- 7.1 vs. 50.1 +/- 4.1 fmol/10(6) plts), DHEA-S (13.6 +/- 0.8 vs. 3.0 +/- 0.3 micromol/l), DHEA (23.6 +/- 1.7 vs. 15.3 +/- 1.4 nmol/l), testosterone (23.6 +/- 1.0 vs. 17.7 +/- 1.0 nmol/l) and E(2) (72.0 +/- 5.0 vs. 60.0 +/- 4.0 pmol/l); and (b) decreased (P < 0.05 vs. baseline) PAI-1 Ag (27.4 +/- 3.8 vs. 21.5 +/- 2.5 ng/ml) and low-density lipoprotein (LDL) cholesterol (3.4 +/- 0.2 vs. 3.0 +/- 0.2 mmol/l). IGF-I, insulin, glucose, triglycerides, total cholesterol, HDL cholesterol, HDL2 cholesterol, HDL3 cholesterol, apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB) and homocysteine levels were not modified by DHEA treatment. This study shows that short-term treatment with DHEA increased platelet cGMP production, a marker of NO production, in healthy elderly subjects. This effect is coupled with a decrease in PAI-1

  11. Ethanol extract of seeds of Oenothera odorata induces vasorelaxation via endothelium-dependent NO-cGMP signaling through activation of Akt-eNOS-sGC pathway.

    Science.gov (United States)

    Kim, Hye Yoom; Oh, Hyuncheol; Li, Xiang; Cho, Kyung Woo; Kang, Dae Gill; Lee, Ho Sub

    2011-01-27

    The vasorelaxant effect of ethanol extract of seeds of Oenothera odorata (Onagraceae) (one species of evening primroses) (ESOO) and its mechanisms involved were defined. Changes in vascular tension, guanosine 3',5'-cyclic monophosphate (cGMP) levels, and Akt expression were measured in carotid arterial rings from rats. Seeds of Oenothera odorata were extracted with ethanol (94%) and the extract was filtered, concentrated and stored at -70°C. ESOO relaxed endothelium-intact, but not endothelium-denuded, carotid arterial rings in a concentration-dependent manner. Similarly, ESOO increased cGMP levels of the carotid arterial rings. Pretreatment of endothelium-intact arterial rings with L-NAME, an inhibitor of nitric oxide synthase (NOS), or ODQ, an inhibitor of soluble guanylyl cyclase (sGC), blocked the ESOO-induced vasorelaxation and increase in cGMP levels. Nominally Ca(2+)-free but not L-typed Ca(2+) channel inhibition attenuated the ESOO-induced vasorelaxation. Thapsigargin, Gd(3+), and 2-aminoethyl diphenylborinate, modulators of store-operated Ca(2+) entry (SOCE), significantly attenuated the ESOO-induced vasorelaxation and increase in cGMP levels. Further, wortmannin, an inhibitor of Akt, attenuated the ESOO-induced vasorelaxation and increases in cGMP levels and phosphorylated Akt2 expression. K(+) channel blockade with TEA, 4-aminopyridine, and glibenclamide attenuated the ESOO-induced vascular relaxation. Taken together, the present study demonstrates that ESOO relaxes vascular smooth muscle via endothelium-dependent NO-cGMP signaling through activation of the Akt-eNOS-sGC pathway. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  12. The role of cGMP as a mediator of lipolysis in bovine oocytes and its effects on embryo development and cryopreservation.

    Directory of Open Access Journals (Sweden)

    Kátia R L Schwarz

    Full Text Available This study aimed to determine the influence of cyclic guanosine 3'5'-monophosphate (cGMP and cGMP-dependent kinase (PKG during in vitro maturation (IVM on lipolysis-related parameters in bovine cumulus-oocyte complexes (COCs, and on embryo development and cryosurvival. COCs were matured with cGMP/PKG modulators and assessed for metaphase II rates (MII, cGMP levels, lipid content in oocytes (OO, transcript abundance for genes involved in lipolysis (ATGL and lipid droplets (PLIN2 in cumulus cells (CC and OO, and presence of phosphorylated (active hormone sensitive lipase (HSLser563 in OO. Embryo development, lipid contents and survival to vitrification were also assessed. Phosphodiesterase 5 inhibition (PDE5; cGMP-hydrolyzing enzyme with 10-5M sildenafil (SDF during 24 h IVM increased cGMP in COCs (56.9 vs 9.5 fMol/COC in untreated controls, p<0.05 and did not affect on maturation rate (84.3±6.4% MII. Fetal calf serum (FCS in IVM medium decreased cGMP in COCs compared to bovine serum albumin (BSA + SDF (19.6 vs 66.5 fMol/COC, respectively, p<0.05. FCS increased lipid content in OO (40.1 FI, p<0.05 compared to BSA (34.6 FI, while SDF decreased (29.8 and 29.6 FI, with BSA or FCS, respectively p<0.05. PKG inhibitor (KT5823 reversed this effect (38.9 FI, p<0.05. ATGL and PLIN2 transcripts were detected in CC and OO, but were affected by cGMP and PKG only in CC. HSLser563 was detected in OO matured with or without modulators. Reduced lipid content in embryos were observed only when SDF was added during IVM and IVC (27.6 FI compared to its use in either or none of the culture periods (34.2 FI, p<0.05. Survival to vitrification was unaffected by SDF. In conclusion, cGMP and PKG are involved in lipolysis in OO and possibly in CC and embryos; serum negatively affects this pathway, contributing to lipid accumulation, and cGMP modulation may reduce lipid contents in oocytes and embryos, but without improving embryo cryotolerance.

  13. Brain-natriuretic peptide and cyclic guanosine monophosphate as biomarkers of myxomatous mitral valve disease in dogs

    DEFF Research Database (Denmark)

    Moesgaard, Sophia Gry; Falk, Bo Torkel; Teerlink, Tom

    2011-01-01

    Elevations in the plasma concentrations of natriuretic peptides correlate with increased severity of myxomatous mitral valve disease (MMVD) in dogs. This study correlates the severity of MMVD with the plasma concentrations of the biomarkers N-terminal fragment of the pro-brain-natriuretic peptide...... (NT-proBNP) and its second messenger, cyclic guanosine monophosphate (cGMP). Furthermore, the l-arginine:asymmetric dimethylarginine (ADMA) ratio was measured as an index of nitric oxide availability. The study included 75 dogs sub-divided into five groups based on severity of MMVD as assessed...... by clinical examination and echocardiography. Plasma NT-proBNP and cGMP concentrations increased with increasing valve dysfunction and were significantly elevated in dogs with heart failure. The cGMP:NT-proBNP ratio decreased significantly in dogs with heart failure, suggesting the development of natriuretic...

  14. Hepatic oxidative stress in ovariectomized transgenic mice expressing the hepatitis C virus polyprotein is augmented through suppression of adenosine monophosphate-activated protein kinase/proliferator-activated receptor gamma co-activator 1 alpha signaling.

    Science.gov (United States)

    Tomiyama, Yasuyuki; Nishina, Sohji; Hara, Yuichi; Kawase, Tomoya; Hino, Keisuke

    2014-10-01

    Oxidative stress plays an important role in hepatocarcinogenesis of hepatitis C virus (HCV)-related chronic liver diseases. Despite the evidence of an increased proportion of females among elderly patients with HCV-related hepatocellular carcinoma (HCC), it remains unknown whether HCV augments hepatic oxidative stress in postmenopausal women. The aim of this study was to determine whether oxidative stress was augmented in ovariectomized (OVX) transgenic mice expressing the HCV polyprotein and to investigate its underlying mechanisms. OVX and sham-operated female transgenic mice expressing the HCV polyprotein and non-transgenic littermates were assessed for the production of reactive oxygen species (ROS), expression of inflammatory cytokines and antioxidant potential in the liver. Compared with OVX non-transgenic mice, OVX transgenic mice showed marked hepatic steatosis and ROS production without increased induction of inflammatory cytokines, but there was no increase in ROS-detoxifying enzymes such as superoxide dismutase 2 and glutathione peroxidase 1. In accordance with these results, OVX transgenic mice showed less activation of peroxisome proliferator-activated receptor-γ co-activator-1α (PGC-1α), which is required for the induction of ROS-detoxifying enzymes, and no activation of adenosine monophosphate-activated protein kinase-α (AMPKα), which regulates the activity of PGC-1α. Our study demonstrated that hepatic oxidative stress was augmented in OVX transgenic mice expressing the HCV polyprotein by attenuation of antioxidant potential through inhibition of AMPK/PGC-1α signaling. These results may account in part for the mechanisms by which HCV-infected women are at high risk for HCC development when some period has passed after menopause. © 2013 The Japan Society of Hepatology.

  15. Molecular properties of mammalian proteins that interact with cGMP: protein kinases, cation channels, phosphodiesterases, and multi-drug anion transporters.

    Science.gov (United States)

    Francis, Sharron H; Blount, Mitsi A; Zoraghi, Roya; Corbin, Jackie D

    2005-09-01

    Cyclic GMP is a critical second messenger signaling molecule in many mammalian cell types. It is synthesized by a family of guanylyl cyclases that is activated in response to stimuli from hormones such as natriuretic peptides, members of the guanylin family, and chemical stimuli including nitric oxide and carbon monoxide. The resulting elevation of cGMP modulates myriad physiological processes. Three major groups of cellular proteins bind cGMP specifically at allosteric sites; interaction of cGMP with these sites modulates the activities and functions of other domains within these protein groups to bring about physiological effects. These proteins include the cyclic nucleotide (cN)-dependent protein kinases, cN-gated cation channels, and cGMP-binding phosphodiesterases (PDE). Cyclic GMP also interacts with the catalytic sites of many cN PDEs and with some members of the multi-drug anion transporter family (MRPs) which can extrude nucleotides from cells. The allosteric cN-binding sites in the kinases and the cN-gated channels are evolutionarily and biochemically related, whereas the allosteric cGMP-binding sites in PDEs (also known as GAF domains), the catalytic sites of PDEs , and the ligand-binding sites in the MRPs are evolutionarily and biochemically distinct from each other and from those in the kinase and channel families. The sites that interact with cGMP within each of these groups of proteins have unique properties that provide for cGMP binding. Within a given cell, cGMP can potentially interact with members of all these groups of proteins if they are present. The relative abundance and affinities of these various cGMP-binding sites in conjunction with their subcellular compartmentation, proximity to cyclases and PDEs, and post-translational modification contribute importantly in determining the impact of these respective proteins to cGMP signaling within a particular cell.

  16. The plant natriuretic peptide receptor is a guanylyl cyclase and enables cGMP-dependent signaling

    KAUST Repository

    Turek, Ilona

    2016-03-05

    The functional homologues of vertebrate natriuretic peptides (NPs), the plant natriuretic peptides (PNPs), are a novel class of peptidic hormones that signal via guanosine 3′,5′-cyclic monophosphate (cGMP) and systemically affect plant salt and water balance and responses to biotrophic plant pathogens. Although there is increasing understanding of the complex roles of PNPs in plant responses at the systems level, little is known about the underlying signaling mechanisms. Here we report isolation and identification of a novel Leucine-Rich Repeat (LRR) protein that directly interacts with A. thaliana PNP, AtPNP-A. In vitro binding studies revealed that the Arabidopsis AtPNP-A binds specifically to the LRR protein, termed AtPNP-R1, and the active region of AtPNP-A is sufficient for the interaction to occur. Importantly, the cytosolic part of the AtPNP-R1, much like in some vertebrate NP receptors, harbors a catalytic center diagnostic for guanylyl cyclases and the recombinant AtPNP-R1 is capable of catalyzing the conversion of guanosine triphosphate to cGMP. In addition, we show that AtPNP-A causes rapid increases of cGMP levels in wild type (WT) leaf tissue while this response is significantly reduced in the atpnp-r1 mutants. AtPNP-A also causes cGMP-dependent net water uptake into WT protoplasts, and hence volume increases, whereas responses of the protoplasts from the receptor mutant are impaired. Taken together, our results suggest that the identified LRR protein is an AtPNP-A receptor essential for the PNP-dependent regulation of ion and water homeostasis in plants and that PNP- and vertebrate NP-receptors and their signaling mechanisms share surprising similarities. © 2016 Springer Science+Business Media Dordrecht

  17. The Role of Growth Factors (VEGF, TGF-β1 and Cyclic Guanosine Monophosphate in the Formation of Pulmonary Hypertension in Children with Bronchopulmonary Dysplasia

    Directory of Open Access Journals (Sweden)

    A.S. Senatorova

    2013-10-01

    Full Text Available In 82 children with bronchopulmonary dysplasia (from 1 to 36 months of corrected age we investigated the level of VEGF, TGF-β1 in blood and cyclic guanosine monophosphate (cGMP in sputum. It was revealed that children with bronchopulmonary dysplasia had a significant increase in TGF-β1 (p < 0.05 and cGMP (p < 0.01–0.001, reduced VEGF (p < 0.05, indicating inhibition of angiogenesis, activation of fibrosis factors and endothelium-dependent vasodilation. Reliable direct dependence of activation of TGF-β1 in blood and cGMP in sputum, as well as inverse correlation between VEGF in blood and rLA had been proved, which gave reason to think of pulmonary hypertension as an adverse factor in fibrosis activation and angiogenesis inhibition in children with bronchopulmonary dysplasia. Reduced oxygen saturation and oxygen partial pressure moderately activated cGMP, but did not provide a sufficient reduction of pressure in the pulmonary artery.

  18. Optogenetic manipulation of cGMP in cells and animals by the tightly light-regulated guanylyl-cyclase opsin CyclOp.

    Science.gov (United States)

    Gao, Shiqiang; Nagpal, Jatin; Schneider, Martin W; Kozjak-Pavlovic, Vera; Nagel, Georg; Gottschalk, Alexander

    2015-09-08

    Cyclic GMP (cGMP) signalling regulates multiple biological functions through activation of protein kinase G and cyclic nucleotide-gated (CNG) channels. In sensory neurons, cGMP permits signal modulation, amplification and encoding, before depolarization. Here we implement a guanylyl cyclase rhodopsin from Blastocladiella emersonii as a new optogenetic tool (BeCyclOp), enabling rapid light-triggered cGMP increase in heterologous cells (Xenopus oocytes, HEK293T cells) and in Caenorhabditis elegans. Among five different fungal CyclOps, exhibiting unusual eight transmembrane topologies and cytosolic N-termini, BeCyclOp is the superior optogenetic tool (light/dark activity ratio: 5,000; no cAMP production; turnover (20 °C) ∼17 cGMP s(-1)). Via co-expressed CNG channels (OLF in oocytes, TAX-2/4 in C. elegans muscle), BeCyclOp photoactivation induces a rapid conductance increase and depolarization at very low light intensities. In O2/CO2 sensory neurons of C. elegans, BeCyclOp activation evokes behavioural responses consistent with their normal sensory function. BeCyclOp therefore enables precise and rapid optogenetic manipulation of cGMP levels in cells and animals.

  19. Plasma concentrations of the cyclic nucleotides, adenosine 3',5'-monophosphate and guanosine 3'.5'-monophosphate, in healthy adults treated with theophylline

    DEFF Research Database (Denmark)

    Fenger, M; Eriksen, P B; Andersen, O

    1982-01-01

    Plasma concentrations of cyclic adenosine monophosphate and cyclic guanosine monophosphate were measured in 10 health adults before, during and after periods of theophylline administration. Cyclic adenosine monophosphate concentrations did not change significantly, but cyclic guanosine monophosph...

  20. cGMP inhibition of type 3 phosphodiesterase is the major mechanism by which C-type natriuretic peptide activates CFTR in the shark rectal gland

    Science.gov (United States)

    De Jonge, Hugo R.; Tilly, Ben C.; Hogema, Boris M.; Pfau, Daniel J.; Kelley, Catherine A.; Kelley, Megan H.; Melita, August M.; Morris, Montana T.; Viola, Ryan M.

    2013-01-01

    The in vitro perfused rectal gland of the dogfish shark (Squalus acanthias) and filter-grown monolayers of primary cultures of shark rectal gland (SRG) epithelial cells were used to analyze the signal transduction pathway by which C-type natriuretic peptide (CNP) stimulates chloride secretion. CNP binds to natriuretic receptors in the basolateral membrane, elevates cellular cGMP, and opens cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels in the apical membrane. CNP-provoked chloride secretion was completely inhibitable by the nonspecific protein kinase inhibitor staurosporine and the PKA inhibitor H89 but insensitive to H8, an inhibitor of type I and II isoforms of cGMP-dependent protein kinase (cGKI and cGKII). CNP-induced secretion could not be mimicked by nonhydrolyzable cGMP analogs added alone or in combination with the protein kinase C activator phorbolester, arguing against a role for cGK or for cGMP-induced PKC signaling. We failed to detect a dogfish ortholog of cGKII by molecular cloning and affinity chromatography. However, inhibitors of the cGMP-inhibitable isoform of phosphodiesterase (PDE3) including milrinone, amrinone, and cilostamide but not inhibitors of other PDE isoenzymes mimicked the effect of CNP on chloride secretion in perfused glands and monolayers. CNP raised cGMP and cAMP levels in the SRG epithelial cells. This rise in cAMP as well as the CNP and amrinone-provoked chloride secretion, but not the rise in cGMP, was almost completely blocked by the Gαi-coupled adenylyl cyclase inhibitor somatostatin, arguing against a role for cGMP cross-activation of PKA in CNP action. These data provide molecular, functional, and pharmacological evidence for a CNP/cGMP/PDE3/cAMP/PKA signaling cascade coupled to CFTR in the SRG. PMID:24259420

  1. Phosphodiesterase 9A regulates central cGMP and modulates responses to cholinergic and monoaminergic perturbation in vivo.

    Science.gov (United States)

    Kleiman, Robin J; Chapin, Douglas S; Christoffersen, Curt; Freeman, Jody; Fonseca, Kari R; Geoghegan, Kieran F; Grimwood, Sarah; Guanowsky, Victor; Hajós, Mihály; Harms, John F; Helal, Christopher J; Hoffmann, William E; Kocan, Geralyn P; Majchrzak, Mark J; McGinnis, Dina; McLean, Stafford; Menniti, Frank S; Nelson, Fredrick; Roof, Robin; Schmidt, Anne W; Seymour, Patricia A; Stephenson, Diane T; Tingley, Francis David; Vanase-Frawley, Michelle; Verhoest, Patrick R; Schmidt, Christopher J

    2012-05-01

    Cyclic nucleotides are critical regulators of synaptic plasticity and participate in requisite signaling cascades implicated across multiple neurotransmitter systems. Phosphodiesterase 9A (PDE9A) is a high-affinity, cGMP-specific enzyme widely expressed in the rodent central nervous system. In the current study, we observed neuronal staining with antibodies raised against PDE9A protein in human cortex, cerebellum, and subiculum. We have also developed several potent, selective, and brain-penetrant PDE9A inhibitors and used them to probe the function of PDE9A in vivo. Administration of these compounds to animals led to dose-dependent accumulation of cGMP in brain tissue and cerebrospinal fluid, producing a range of biological effects that implied functional significance for PDE9A-regulated cGMP in dopaminergic, cholinergic, and serotonergic neurotransmission and were consistent with the widespread distribution of PDE9A. In vivo effects of PDE9A inhibition included reversal of the respective disruptions of working memory by ketamine, episodic and spatial memory by scopolamine, and auditory gating by amphetamine, as well as potentiation of risperidone-induced improvements in sensorimotor gating and reversal of the stereotypic scratching response to the hallucinogenic 5-hydroxytryptamine 2A agonist mescaline. The results suggested a role for PDE9A in the regulation of monoaminergic circuitry associated with sensory processing and memory. Thus, PDE9A activity regulates neuronal cGMP signaling downstream of multiple neurotransmitter systems, and inhibition of PDE9A may provide therapeutic benefits in psychiatric and neurodegenerative diseases promoted by the dysfunction of these diverse neurotransmitter systems.

  2. Breast cancer drugs dampen vascular functions by interfering with nitric oxide signaling in endothelium

    Energy Technology Data Exchange (ETDEWEB)

    Gajalakshmi, Palanivel; Priya, Mani Krishna; Pradeep, Thangaraj; Behera, Jyotirmaya; Muthumani, Kandasamy; Madhuwanti, Srinivasan; Saran, Uttara; Chatterjee, Suvro, E-mail: soovro@yahoo.ca

    2013-06-01

    Widely used chemotherapeutic breast cancer drugs such as Tamoxifen citrate (TC), Capecitabine (CP) and Epirubicin (EP) are known to cause various cardiovascular side-effects among long term cancer survivors. Vascular modulation warrants nitric oxide (NO) signal transduction, which targets the vascular endothelium. We hypothesize that TC, CP and EP interference with the nitric oxide downstream signaling specifically, could lead to cardiovascular dysfunctions. The results demonstrate that while all three drugs attenuate NO and cyclic guanosine mono-phosphate (cGMP) production in endothelial cells, they caused elevated levels of NO in the plasma and RBC. However, PBMC and platelets did not show any significant changes under treatment. This implies that the drug effects are specific to the endothelium. Altered eNOS and phosphorylated eNOS (Ser-1177) localization patterns in endothelial cells were observed following drug treatments. Similarly, the expression of phosphorylated eNOS (Ser-1177) protein was decreased under the treatment of drugs. Altered actin polymerization was also observed following drug treatment, while addition of SpNO and 8Br-cGMP reversed this effect. Incubation with the drugs decreased endothelial cell migration whereas addition of YC-1, SC and 8Br-cGMP recovered the effect. Additionally molecular docking studies showed that all three drugs exhibited a strong binding affinity with the catalytic domain of human sGC. In conclusion, results indicate that TC, CP and EP cause endothelial dysfunctions via the NO–sGC–cGMP pathway and these effects could be recovered using pharmaceutical agonists of NO signaling pathway. Further, the study proposes a combination therapy of chemotherapeutic drugs and cGMP analogs, which would confer protection against chemotherapy mediated vascular dysfunctions in cancer patients. - Highlights: • NO production is reduced in endothelial cells under breast cancer drug treatment. • Cellular cGMP level is decreased under

  3. Breast cancer drugs dampen vascular functions by interfering with nitric oxide signaling in endothelium

    International Nuclear Information System (INIS)

    Gajalakshmi, Palanivel; Priya, Mani Krishna; Pradeep, Thangaraj; Behera, Jyotirmaya; Muthumani, Kandasamy; Madhuwanti, Srinivasan; Saran, Uttara; Chatterjee, Suvro

    2013-01-01

    Widely used chemotherapeutic breast cancer drugs such as Tamoxifen citrate (TC), Capecitabine (CP) and Epirubicin (EP) are known to cause various cardiovascular side-effects among long term cancer survivors. Vascular modulation warrants nitric oxide (NO) signal transduction, which targets the vascular endothelium. We hypothesize that TC, CP and EP interference with the nitric oxide downstream signaling specifically, could lead to cardiovascular dysfunctions. The results demonstrate that while all three drugs attenuate NO and cyclic guanosine mono-phosphate (cGMP) production in endothelial cells, they caused elevated levels of NO in the plasma and RBC. However, PBMC and platelets did not show any significant changes under treatment. This implies that the drug effects are specific to the endothelium. Altered eNOS and phosphorylated eNOS (Ser-1177) localization patterns in endothelial cells were observed following drug treatments. Similarly, the expression of phosphorylated eNOS (Ser-1177) protein was decreased under the treatment of drugs. Altered actin polymerization was also observed following drug treatment, while addition of SpNO and 8Br-cGMP reversed this effect. Incubation with the drugs decreased endothelial cell migration whereas addition of YC-1, SC and 8Br-cGMP recovered the effect. Additionally molecular docking studies showed that all three drugs exhibited a strong binding affinity with the catalytic domain of human sGC. In conclusion, results indicate that TC, CP and EP cause endothelial dysfunctions via the NO–sGC–cGMP pathway and these effects could be recovered using pharmaceutical agonists of NO signaling pathway. Further, the study proposes a combination therapy of chemotherapeutic drugs and cGMP analogs, which would confer protection against chemotherapy mediated vascular dysfunctions in cancer patients. - Highlights: • NO production is reduced in endothelial cells under breast cancer drug treatment. • Cellular cGMP level is decreased under

  4. Studies on Relationship between Serum Nitric Oxide and Plasma Cyclic Guanosine Monophosphate and Prolonged Bleeding after Medical Abortion as well as Prophylaxis and Treatment of Bleeding with Traditional Chinese Medicine

    Institute of Scientific and Technical Information of China (English)

    廖玎玲; 谭布珍; 辛华; 贺晓菊

    1999-01-01

    Objectives To study the relationship between serum nitric oxide(NO and plasma cyclic guanosine monophosphate(cGMP)and prolonged bleeding after medical abortion.Methods A total of 120women having received medical abortions at random were recruited and divided into two groups:the one(Group A,n=60) taking “Gong-Fu Mixture(Uterus-Recovering Mixture)”and the other(Group B,n=60)not taking it after abortion.On d 10,20 and 30 after medical abortion,serum NO and plasma cGMP were tested before and after mifepristone administration and 10 d later by Gresis reac-tion method and radioimmunoassay respectively.Results NO concentration in serum and cGMP concentration in plasma decreased signifi-cantly after taking mifeprlstone given(P<0. 05).Ten days later,the number of thos ewith bleeding discontinuation in the group A was significantly greater than that in the group B(P<0.05).Serum NO level and plasma cGMP level in the group A de-creased more significantly than those in the group B(P<0. 05).Conclusion The slow decrease of serum NO and plasma cGMP is closely related to prolonged bleeding after medical abortion.“Gong-Fu Mixture(uterus-recovering mixture)”is effective in prevention and treatment of prolonged bleeding.

  5. Filtration behavior of casein glycomacropeptide (CGMP) in an enzymatic membrane reactor: fouling control by membrane selection and threshold flux operation

    DEFF Research Database (Denmark)

    Luo, Jianquan; Morthensen, Sofie Thage; Meyer, Anne S.

    2014-01-01

    . In this study, the filtration performance and fouling behavior during ultrafiltration (UF) of CGMP for the enzymatic production of 3′-sialyllactose were investigated. A 5kDa regenerated cellulose membrane with high anti-fouling performance, could retain CGMP well, permeate 3′-sialyllactose, and was found...... to be the most suitable membrane for this application. Low pH increased CGMP retention but produced more fouling. Higher agitation and lower CGMP concentration induced larger permeate flux and higher CGMP retention. Adsorption fouling and pore blocking by CGMP in/on membranes could be controlled by selecting...... a highly hydrophilic membrane with appropriate pore size. Operating under threshold flux could minimize the concentration polarization and cake/gel/scaling layers, but might not avoid irreversible fouling caused by adsorption and pore blocking. The effects of membrane properties, pH, agitation and CGMP...

  6. Purification and characterization of cGMP binding protein-phosphodiesterase from rat lung

    International Nuclear Information System (INIS)

    Francis, S.H.; Walseth, T.F.; Corbin, J.D.

    1986-01-01

    The cGMP binding protein-phosphodiesterase (cG-BPP) with a phosphodiesterase specific activity of 7 μM/min/mg has been purified from rat lung by sequential chromatography on DEAE-cellulose, Blue-Sepharose, zinc chelate affinity adsorbent and HPLC-DEAE. Migration of the major band on SDS-PAGE corresponds to a MW of ∼93,000. Both cGMP phosphodiesterase activity and cGMP binding from the HPLC-DEAE profile correlate with this band. Since the authors previous work has determined the native MW to be ∼177,000, this suggests a dimeric structure comprised of two 93,000 MW subunits for the rat lung cG-BPP. At low cGMP concentrations, cGMP binding is stimulated ∼20-fold by histone and ∼5-fold by 3-isobutyl-1-methylxanthine(IBMX). The purified protein has one component of cGMP dissociation with a rate constant of 0.045/min. Photolysis of the purified protein in the presence of 32 P-cGMP labels the 93,000 MW band and this labeling is increased by IBMX, indicating that the 93,000 MW band is a subunit of the cGMP-BPP. This implies that the enzyme preparation is nearly homogeneous, a conclusion also supported by a minimum [ 3 H]-cGMP binding stoichiometry of 0.5 mol per 93,000 subunit. An additional protein band with a MW of ∼90,000 also occurs in these preparations which exhibits behavior similar to the 93,000 MW protein. N 2 -Hexyl-cGMP inhibits phosphodiesterase activity by competing with cGMP for hydrolysis at the catalytic site but not at the binding site. N 2 -Hexyl cGMP actually increases cGMP binding. This provides the first evidence that cGMP binding is increased by compounds hydrolyzed at the catalytic site. This interaction between the binding and phosphodiesterase sites could be important in the regulation of the functions of these sites in vivo

  7. Primary adenosine monophosphate (AMP) deaminase deficiency in a hypotonic infant.

    Science.gov (United States)

    Castro-Gago, Manuel; Gómez-Lado, Carmen; Pérez-Gay, Laura; Eirís-Puñal, Jesús; Martínez, Elena Pintos; García-Consuegra, Inés; Martín, Miguel Angel

    2011-06-01

    The spectrum of the adenosine monophosphate (AMP) deaminase deficiency ranges from asymptomatic carriers to patients who manifest exercise-induced muscle pain, occasionally rhabdomyolysis, and idiopathic hyperCKemia. However, previous to the introduction of molecular techniques, rare cases with congenital weakness and hypotonia have also been reported. We report a 6-month-old girl with the association of congenital muscle weakness and hypotonia, muscle deficiency of adenosine monophosphate deaminase, and the homozygous C to T mutation at nucleotide 34 of the adenosine monophosphate deaminase-1 gene. This observation indicates the possible existence of a primary adenosine monophosphate deaminase deficiency manifested by congenital muscle weakness and hypotonia.

  8. Molecular Analysis of Sensory Axon Branching Unraveled a cGMP-Dependent Signaling Cascade

    Directory of Open Access Journals (Sweden)

    Alexandre Dumoulin

    2018-04-01

    Full Text Available Axonal branching is a key process in the establishment of circuit connectivity within the nervous system. Molecular-genetic studies have shown that a specific form of axonal branching—the bifurcation of sensory neurons at the transition zone between the peripheral and the central nervous system—is regulated by a cyclic guanosine monophosphate (cGMP-dependent signaling cascade which is composed of C-type natriuretic peptide (CNP, the receptor guanylyl cyclase Npr2, and cGMP-dependent protein kinase Iα (cGKIα. In the absence of any one of these components, neurons in dorsal root ganglia (DRG and cranial sensory ganglia no longer bifurcate, and instead turn in either an ascending or a descending direction. In contrast, collateral axonal branch formation which represents a second type of axonal branch formation is not affected by inactivation of CNP, Npr2, or cGKI. Whereas axon bifurcation was lost in mouse mutants deficient for components of CNP-induced cGMP formation; the absence of the cGMP-degrading enzyme phosphodiesterase 2A had no effect on axon bifurcation. Adult mice that lack sensory axon bifurcation due to the conditional inactivation of Npr2-mediated cGMP signaling in DRG neurons demonstrated an altered shape of sensory axon terminal fields in the spinal cord, indicating that elaborate compensatory mechanisms reorganize neuronal circuits in the absence of bifurcation. On a functional level, these mice showed impaired heat sensation and nociception induced by chemical irritants, whereas responses to cold sensation, mechanical stimulation, and motor coordination are normal. These data point to a critical role of axon bifurcation for the processing of acute pain perception.

  9. Molecular Analysis of Sensory Axon Branching Unraveled a cGMP-Dependent Signaling Cascade.

    Science.gov (United States)

    Dumoulin, Alexandre; Ter-Avetisyan, Gohar; Schmidt, Hannes; Rathjen, Fritz G

    2018-04-24

    Axonal branching is a key process in the establishment of circuit connectivity within the nervous system. Molecular-genetic studies have shown that a specific form of axonal branching—the bifurcation of sensory neurons at the transition zone between the peripheral and the central nervous system—is regulated by a cyclic guanosine monophosphate (cGMP)-dependent signaling cascade which is composed of C-type natriuretic peptide (CNP), the receptor guanylyl cyclase Npr2, and cGMP-dependent protein kinase Iα (cGKIα). In the absence of any one of these components, neurons in dorsal root ganglia (DRG) and cranial sensory ganglia no longer bifurcate, and instead turn in either an ascending or a descending direction. In contrast, collateral axonal branch formation which represents a second type of axonal branch formation is not affected by inactivation of CNP, Npr2, or cGKI. Whereas axon bifurcation was lost in mouse mutants deficient for components of CNP-induced cGMP formation; the absence of the cGMP-degrading enzyme phosphodiesterase 2A had no effect on axon bifurcation. Adult mice that lack sensory axon bifurcation due to the conditional inactivation of Npr2-mediated cGMP signaling in DRG neurons demonstrated an altered shape of sensory axon terminal fields in the spinal cord, indicating that elaborate compensatory mechanisms reorganize neuronal circuits in the absence of bifurcation. On a functional level, these mice showed impaired heat sensation and nociception induced by chemical irritants, whereas responses to cold sensation, mechanical stimulation, and motor coordination are normal. These data point to a critical role of axon bifurcation for the processing of acute pain perception.

  10. Nitric oxide participates in cold-inhibited Camellia sinensis pollen germination and tube growth partly via cGMP in vitro.

    Directory of Open Access Journals (Sweden)

    Yu-Hua Wang

    Full Text Available Nitric oxide (NO plays essential roles in many biotic and abiotic stresses in plant development procedures, including pollen tube growth. Here, effects of NO on cold stress inhibited pollen germination and tube growth in Camellia sinensis were investigated in vitro. The NO production, NO synthase (NOS-like activity, cGMP content and proline (Pro accumulation upon treatment with NO scavenger cPTIO, NOS inhibitor L-NNA, NO donor DEA NONOate, guanylate cyclase (GC inhibitor ODQ or phosphodiesterase (PDE inhibitor Viagra at 25°C (control or 4°C were analyzed. Exposure to 4°C for 2 h reduced pollen germination and tube growth along with increase of NOS-like activity, NO production and cGMP content in pollen tubes. DEA NONOate treatment inhibited pollen germination and tube growth in a dose-dependent manner under control and reinforced the inhibition under cold stress, during which NO production and cGMP content promoted in pollen tubes. L-NNA and cPTIO markedly reduced the generation of NO induced by cold or NO donor along with partly reverse of cold- or NO donor-inhibited pollen germination and tube growth. Furthermore, ODQ reduced the cGMP content under cold stress and NO donor treatment in pollen tubes. Meanwhile, ODQ disrupted the reinforcement of NO donor on the inhibition of pollen germination and tube growth under cold condition. Additionally, Pro accumulation of pollen tubes was reduced by ODQ compared with that receiving NO donor under cold or control condition. Effects of cPTIO and L-NNA in improving cold-treated pollen germination and pollen tube growth could be lowered by Viagra. Moreover, the inhibitory effects of cPTIO and L-NNA on Pro accumulation were partly reversed by Viagra. These data suggest that NO production from NOS-like enzyme reaction decreased the cold-responsive pollen germination, inhibited tube growth and reduced Pro accumulation, partly via cGMP signaling pathway in C. sinensis.

  11. A cGMP kinase mutant with increased sensitivity to the protein kinase inhibitor peptide PKI(5-24).

    Science.gov (United States)

    Ruth, P; Kamm, S; Nau, U; Pfeifer, A; Hofmann, F

    1996-01-01

    Synthetic peptides corresponding to the active domain of the heat-stable inhibitor protein PKI are very potent inhibitors of cAMP-dependent protein kinase, but are extremely weak inhibitors of cGMP-dependent protein kinase. In this study, we tried to confer PKI sensitivity to cGMP kinase by site-directed mutagenesis. The molecular requirements for high affinity inhibition by PKI were deduced from the crystal structure of the cAMP kinase/PKI complex. A prominent site of interaction are residues Tyr235 and Phe239 in the catalytic subunit, which from a sandwich-like structure with Phe10 of the PKI(5-24) peptide. To increase the sensitivity for PKI, the cGMP kinase codons at the corresponding sites, Ser555 and Ser559, were changed to Tyr and Phe. The mutant cGMP kinase was stimulated half maximally by cGMP at 3-fold higher concentrations (240 nM) than the wild type (77 nM). Wild type and mutant cGMP kinase did not differ significantly in their Km and Vmax for three different substrate peptides. The PKI(5-24) peptide inhibited phosphotransferase activity of the mutant cGMP kinase with higher potency than that of wild type, with Ki values of 42 +/- .3 microM and 160 +/- .7 microM, respectively. The increased affinity of the mutant cGMP kinase was specific for the PKI(5-24) peptide. Mutation of the essential Phe10 in the PKI(5-24) sequence to an Ala yielded a peptide that inhibited mutant and wild type cGMP kinase with similar potency, with Ki values of 160 +/- 11 and 169 +/- 27 microM, respectively. These results suggest that the mutations Ser555Tyr and Ser559Phe are required, but not sufficient, for high affinity inhibition of cGMP kinase by PKI.

  12. Rapid synthesis of triazine inhibitors of inosine monophosphate dehydrogenase.

    Science.gov (United States)

    Pitts, William J; Guo, Junqing; Dhar, T G Murali; Shen, Zhongqi; Gu, Henry H; Watterson, Scott H; Bednarz, Mark S; Chen, Bang Chi; Barrish, Joel C; Bassolino, Donna; Cheney, Daniel; Fleener, Catherine A; Rouleau, Katherine A; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2002-08-19

    A series of novel triazine-based small molecule inhibitors (IV) of inosine monophosphate dehydrogenase was prepared. The synthesis and the structure-activity relationships (SAR) derived from in vitro studies are described.

  13. Novel amide-based inhibitors of inosine 5'-monophosphate dehydrogenase.

    Science.gov (United States)

    Watterson, Scott H; Liu, Chunjian; Dhar, T G Murali; Gu, Henry H; Pitts, William J; Barrish, Joel C; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2002-10-21

    A series of novel amide-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are described.

  14. [Aging reduces contents of endogenous CO, cAMP and cGMP in rat penile tissues].

    Science.gov (United States)

    Qin, Wen-Bo; Wang, Shu-Qiu; Li, Ming; Kang, Yu-Ming; Gui, Shi-Liang; Chi, Bao-Jin

    2009-02-01

    To explore the relationship of aging with the changes of endogenous carbon monoxide (CO), cGMP and cAMP contents in the penile tissues of rats. Twenty-four male rats were equally divided into an 8-month, a 16-month and a 24-month group, and their penile erection was detected by injecting apomorphine, their penile cavernous body harvested, and the contents of CO, cAPM and cGMP detected by improved dual wavelength spectrophotometry. The contents of CO, cAPM and cGMP were reduced with the increase of age, with statistically significant differences between the three age groups (P < 0.01). Aging significantly decreased the contents of CO, cAMP and cGMP in the penile tissues of the rats, which suggests that aging might play an important role in erectile dysfunction.

  15. Adenosine Monophosphate (AMP)-Activated Protein Kinase: A New Target for Nutraceutical Compounds.

    Science.gov (United States)

    Marín-Aguilar, Fabiola; Pavillard, Luis E; Giampieri, Francesca; Bullón, Pedro; Cordero, Mario D

    2017-01-29

    Adenosine monophosphate-activated protein kinase (AMPK) is an important energy sensor which is activated by increases in adenosine monophosphate (AMP)/adenosine triphosphate (ATP) ratio and/or adenosine diphosphate (ADP)/ATP ratio, and increases different metabolic pathways such as fatty acid oxidation, glucose transport and mitochondrial biogenesis. In this sense, AMPK maintains cellular energy homeostasis by induction of catabolism and inhibition of ATP-consuming biosynthetic pathways to preserve ATP levels. Several studies indicate a reduction of AMPK sensitivity to cellular stress during aging and this could impair the downstream signaling and the maintenance of the cellular energy balance and the stress resistance. However, several diseases have been related with an AMPK dysfunction. Alterations in AMPK signaling decrease mitochondrial biogenesis, increase cellular stress and induce inflammation, which are typical events of the aging process and have been associated to several pathological processes. In this sense, in the last few years AMPK has been identified as a very interesting target and different nutraceutical compounds are being studied for an interesting potential effect on AMPK induction. In this review, we will evaluate the interaction of the different nutraceutical compounds to induce the AMPK phosphorylation and the applications in diseases such as cancer, type II diabetes, neurodegenerative diseases or cardiovascular diseases.

  16. Charge-density-wave instabilities expected in monophosphate tungsten bronzes

    International Nuclear Information System (INIS)

    Canadell, E.; Whangbo, M.

    1991-01-01

    On the basis of tight-binding band calculations, we examined the electronic structures of the tungsten oxide layers found in the monophosphate tungsten bronze (MPTB) phases. The Fermi surfaces of these MPTB phases consist of five well-nested one- and two-dimensional pieces. We calculated the nesting vectors of these Fermi surfaces and discussed the expected charge-density-wave instabilities

  17. Metabolism of inositol 4-monophosphate in rat mammalian tissues

    International Nuclear Information System (INIS)

    Delvaux, A.; Dumont, J.E.; Erneux, C.

    1987-01-01

    Rat brain soluble fraction contains an enzymatic activity that dephosphorylates inositol 1,4-bisphosphate (Ins(1,4)P2). We have used anion exchange h.p.l.c. in order to identify the inositol monophosphate product of Ins(1,4)P2 hydrolysis (i.e. Ins(1)P1, Ins(4)P1 or both). When [ 3 H]Ins(1,4)P2 was used as substrate, we obtained an inositol monophosphate isomer that was separated from the co-injected standard [ 3 H]Ins(1)P1. This suggested an Ins(1,4)P21-phosphatase pathway leading to the production of the inositol 4-monophosphate isomer. The dephosphorylation of [ 32 P]Ins(4)P1 was measured in rat brain, liver and heart soluble fraction and was Li+-sensitive. Chromatography of the soluble fraction of a rat brain homogenate on DEAE-cellulose resolved a monophosphate phosphatase activity that hydrolyzed both [ 3 H]Ins(1)P1 and [4- 32 P]Ins(4)P1 isomers

  18. Novel guanidine-based inhibitors of inosine monophosphate dehydrogenase.

    Science.gov (United States)

    Iwanowicz, Edwin J; Watterson, Scott H; Liu, Chunjian; Gu, Henry H; Mitt, Toomas; Leftheris, Katerina; Barrish, Joel C; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Hollenbaugh, Diane L

    2002-10-21

    A series of novel guanidine-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. IMPDH catalyzes the rate determining step in guanine nucleotide biosynthesis and is a target for anticancer, immunosuppressive and antiviral therapy. The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for this new series of inhibitors is given.

  19. Nitric oxide signaling and the cross talk with prostanoids pathways in vascular system.

    Science.gov (United States)

    Silva, Bruno R; Paula, Tiago D; Paulo, Michele; Bendhack, Lusiane M

    2016-12-28

    This review provides an overview of the cellular signaling of nitric oxide (NO) and prostanoids in vascular cells and the possible cross talk between their pathways, mainly in hypertension, since the imbalance of these two systems has been attributed to development of some cardiovascular diseases. It also deals with the modulation of vasodilation induced by NO donors. NO is a well-known second messenger involved in many cellular functions. In the vascular system, the NO produced by endothelial NO-synthase (eNOS) or released by NO donors acts in vascular smooth muscle cells, the binding of NO to Fe2+-heme of soluble guanylyl-cyclase (sGC) activates sGC and the production of cyclic guanosine-3-5-monophosphate (cGMP). The second messenger (cGMP) activates protein kinase G and the signaling cascade, including K+ channels. Activation of K+ channels leads to cell membrane hyperpolarization and Ca2+ channels blockade, which induce vascular relaxation. Moreover, the enzyme cyclooxygenase (COX) is also an important regulator of the vascular function by prostanoids production such as thromboxane A2 (TXA2) and prostacyclin (PGI2), which classically induce contraction and relaxation, respectively. Additionaly, studies indicate that the activity of both enzymes can be modulated by their products and reactive oxygen species (ROS) in cardiovascular diseases such as hypertension. The interaction of NO with cellular molecules, particularly the reaction of NO with ROS, determines the biological mechanisms of action and short half-life of NO. We have been working on the vascular effects of ruthenium-derived complexes that release NO. Our research group has published works on the vasodilating effects of ruthenium-derived NO donors and the mechanisms of vascular cells involved in the relaxation of the vascular smooth muscle in health and hypertensive rats. In our previous studies, we have compared the new NO donors synthesized by our group to SNP. It shows the cellular signaling of NO

  20. Funktionelle in vitro-Effekte CAMP/CGMP-modulierender Pharmaka am humanen Detrusormuskel

    Directory of Open Access Journals (Sweden)

    Ückert St

    2002-01-01

    Full Text Available Die zyklischen Nukleotidmonophosphate cAMP und cGMP regulieren als intrazelluläre Second Messenger zahlreiche Gewebe- und Organfunktionen. cAMP und cGMP werden von zellulären Adenylat- und Guanylatzyklasen synthetisiert und von Phosphodiesterasen degradiert, die somit Schlüsselenzyme im Prozeß der Tonusregulation glatter Muskulatur sind. Die Markteinführung des PDE5-Inhibitors Sildenafil (Viagra hat dem Konzept der PDE-Inhibition auch in der Urologie breite Akzeptanz verschafft. Eigene Arbeiten der vergangenen Jahre beschreiben die Präsenz der PDE-Isoenzyme 1, 2, 3, 4 und 5 in der Muskulatur des humanen Detrusors und zeigen das klinische Potential des PDE1-Inhibitors Vinpocetin in der Behandlung der motorischen Dranginkontinenz. Mit dem Ziel der Charakterisierung geeigneter Substanzen für die Pharmakotherapie der Detrusorhyperaktivität haben wir die in vitro-Effekte neuer, selektiver Inhibitoren der PDE des Typs 2, 3 und 5 auf isolierte humane Detrusormuskulatur untersucht und mit denen des Diterpens Forskolin (Aktivator der Adenylatzyklase und der Stickoxid (NO-Donatoren Dihydropyridin (DHP und Na+Nitroprussid (NNP verglichen.

  1. Intercellular signaling via cyclic GMP diffusion through gap junctions restarts meiosis in mouse ovarian follicles.

    Science.gov (United States)

    Shuhaibar, Leia C; Egbert, Jeremy R; Norris, Rachael P; Lampe, Paul D; Nikolaev, Viacheslav O; Thunemann, Martin; Wen, Lai; Feil, Robert; Jaffe, Laurinda A

    2015-04-28

    Meiosis in mammalian oocytes is paused until luteinizing hormone (LH) activates receptors in the mural granulosa cells of the ovarian follicle. Prior work has established the central role of cyclic GMP (cGMP) from the granulosa cells in maintaining meiotic arrest, but it is not clear how binding of LH to receptors that are located up to 10 cell layers away from the oocyte lowers oocyte cGMP and restarts meiosis. Here, by visualizing intercellular trafficking of cGMP in real-time in live follicles from mice expressing a FRET sensor, we show that diffusion of cGMP through gap junctions is responsible not only for maintaining meiotic arrest, but also for rapid transmission of the signal that reinitiates meiosis from the follicle surface to the oocyte. Before LH exposure, the cGMP concentration throughout the follicle is at a uniformly high level of ∼2-4 μM. Then, within 1 min of LH application, cGMP begins to decrease in the peripheral granulosa cells. As a consequence, cGMP from the oocyte diffuses into the sink provided by the large granulosa cell volume, such that by 20 min the cGMP concentration in the follicle is uniformly low, ∼100 nM. The decrease in cGMP in the oocyte relieves the inhibition of the meiotic cell cycle. This direct demonstration that a physiological signal initiated by a stimulus in one region of an intact tissue can travel across many layers of cells via cyclic nucleotide diffusion through gap junctions could provide a general mechanism for diverse cellular processes.

  2. cGMP and nitric oxide modulate thrombin-induced endothelial permeability : Regulation via different pathways in human aortic and umbilical vein endothelial cells

    NARCIS (Netherlands)

    Draijer, R.; Atsma, D.E.; Laarse, A. van der; Hinsbergh, V.W.M. van

    1995-01-01

    Previous studies have demonstrated that cGMP and cAMP reduce the endothelial permeability for fluids and macromolecules when the endothelial permeability is increased by thrombin. In this study, we have investigated the mechanism by which cGMP improves the endothelial barrier function and examined

  3. Excessive nitrite affects zebrafish valvulogenesis through yielding too much NO signaling.

    Directory of Open Access Journals (Sweden)

    Junbo Li

    Full Text Available Sodium nitrite, a common food additive, exists widely not only in the environment but also in our body. Excessive nitrite causes toxicological effects on human health; however, whether it affects vertebrate heart valve development remains unknown. In vertebrates, developmental defects of cardiac valves usually lead to congenital heart disease. To understand the toxic effects of nitrite on valvulogenesis, we exposed zebrafish embryos with different concentrations of sodium nitrite. Our results showed that sodium nitrite caused developmental defects of zebrafish heart dose dependently. It affected zebrafish heart development starting from 36 hpf (hour post fertilization when heart initiates looping process. Comprehensive analysis on the embryos at 24 hpf and 48 hpf showed that excessive nitrite did not affect blood circulation, vascular network, myocardium and endocardium development. But development of endocardial cells in atrioventricular canal (AVC of the embryos at 48 hpf was disrupted by too much nitrite, leading to defective formation of primitive valve leaflets at 76 hpf. Consistently, excessive nitrite diminished expressions of valve progenitor markers including bmp4, has2, vcana and notch1b at 48 hpf. Furthermore, 3', 5'-cyclic guanosine monophosphate (cGMP, downstream of nitric oxide (NO signaling, was increased its level significantly in the embryos exposed with excessive nitrite and microinjection of soluble guanylate cyclase inhibitor ODQ (1H-[1], [2], [4]Oxadiazolo[4,3-a] quinoxalin-1-one, an antagonist of NO signaling, into nitrite-exposed embryos could partly rescue the cardiac valve malformation. Taken together, our results show that excessive nitrite affects early valve leaflet formation by producing too much NO signaling.

  4. Post-translational Analysis of Arabidopsis thaliana Proteins in Response to Cyclic Guanosine Monophosphate Treatment

    KAUST Repository

    Parrott, Brian

    2011-01-01

    and phosphorylation before analysis via mass spectrometry. Preliminary results suggest a tendency towards an increased number of phosphorylated proteins as a result of cGMP treatment. The data also showed a sharp increase in methionine oxidation in response

  5. Deoxypyrimidine monophosphate bypass therapy for thymidine kinase 2 deficiency

    OpenAIRE

    Garone, Caterina; Garc??a-D??az, Beatriz; Emmanuele, Valentina; L??pez Garc??a, Luis Carlos; Tadesse, Saba; Akman, Hasan O.; Tanji, Kurenai; Quinzii, Catarina M.; Hirano, Michio

    2014-01-01

    Autosomal recessive mutations in the thymidine kinase 2 gene (TK2) cause mitochondrial DNA depletion, multiple deletions, or both due to loss of TK2 enzyme activity and ensuing unbalanced deoxynucleotide triphosphate (dNTP) pools. To bypass Tk2 deficiency, we administered deoxycytidine and deoxythymidine monophosphates (dCMP+dTMP) to the Tk2 H126N (Tk2 −/− ) knock-in mouse model from postnatal day 4, when mutant mice are phenotypically normal, but biochemically affected. Assessment of 13-day-...

  6. A concise discussion of the regulatory role of cGMP kinase I in cardiac physiology and pathology.

    Science.gov (United States)

    Hofmann, Franz

    2018-06-22

    The underlying cause of cardiac hypertrophy, fibrosis, and heart failure has been investigated in great detail using different mouse models. These studies indicated that cGMP and cGMP-dependent protein kinase type I (cGKI) may ameliorate these negative phenotypes in the adult heart. Recently, evidence has been published that cardiac mitochondrial BKCa channels are a target for cGKI and that activation of mitoBKCa channels may cause some of the positive effects of conditioning in ischemia/reperfusion injury. It will be pointed out that most studies could not present convincing evidence that it is the cGMP level and the activity cGKI in specific cardiac cells that reduces hypertrophy or heart failure. However, anti-fibrotic compounds stimulating nitric oxide-sensitive guanylyl cyclase may be an upcoming therapy for abnormal cardiac remodeling.

  7. Similar expression patterns of bestrophin-4 and cGMP dependent Ca2+-activated chloride channel activity in the vasculature

    DEFF Research Database (Denmark)

    Bouzinova, Elena V.; Larsen, Per; Matchkov, Vladimir

    2008-01-01

    (abstract by Matchkov et. al) that siRNA mediated downregulation of bestrophin-4 is associated with the disappearance of a recently demonstrated2 cGMP-dependent Ca2+-activated Cl- current in vascular smooth muscle cells (SMCs). Here we study the distribution of bestrophin-4-and cGMP dependent Cl- channel...... expressed epitope) Western blot detected a ~65 kDa band in cell lysates from rat mesenteric small arteries and aorta, which was not seen in pulmonary arteries and when preincubated with the immunizing peptide. The distribution of bestrophin-4 mRNA and protein has a pattern similar to the cGMP-dependent Cl......- current in SMCs of different origins. Immunohistochemistry identified bestrophin-4 both in endothelial and SMCs of the vascular tree in the brain, heart, kidney and mesentery, but not in the lungs. We suggest that bestrophin-4 is important for the cGMP dependent, Ca2+ activated Cl- conductance in many...

  8. Inosine monophosphate dehydrogenase messenger RNA expression is correlated to clinical outcomes in mycophenolate mofetil-treated kidney transplant patients, whereas inosine monophosphate dehydrogenase activity is not

    NARCIS (Netherlands)

    Sombogaard, Ferdi; Peeters, Annemiek M. A.; Baan, Carla C.; Mathot, Ron A. A.; Quaedackers, Monique E.; Vulto, Arnold G.; Weimar, Willem; van Gelder, Teun

    2009-01-01

    Measurement of the pharmacodynamic biomarker inosine monophosphate dehydrogenase (IMPDH) activity in renal transplant recipients has been proposed to reflect the biological effect better than using pharmacokinetic parameters to monitor mycophenolate mofetil therapy. The IMPDH assays are however

  9. 5' adenosine monophosphate-activated protein kinase, metabolism and exercise.

    Science.gov (United States)

    Aschenbach, William G; Sakamoto, Kei; Goodyear, Laurie J

    2004-01-01

    The 5' adenosine monophosphate-activated protein kinase (AMPK) is a member of a metabolite-sensing protein kinase family that functions as a metabolic 'fuel gauge' in skeletal muscle. AMPK is a ubiquitous heterotrimeric protein, consisting of an alpha catalytic, and beta and gamma regulatory subunits that exist in multiple isoforms and are all required for full enzymatic activity. During exercise, AMPK becomes activated in skeletal muscle in response to changes in cellular energy status (e.g. increased adenosine monophosphate [AMP]/adenosine triphosphate [ATP] and creatine/phosphocreatine ratios) in an intensity-dependent manner, and serves to inhibit ATP-consuming pathways, and activate pathways involved in carbohydrate and fatty-acid metabolism to restore ATP levels. Recent evidence shows that although AMPK plays this key metabolic role during acute bouts of exercise, it is also an important component of the adaptive response of skeletal muscles to endurance exercise training because of its ability to alter muscle fuel reserves and expression of several exercise-responsive genes. This review discusses the putative roles of AMPK in acute and chronic exercise responses, and suggests avenues for future AMPK research in exercise physiology and biochemistry.

  10. A continuous spectrophotometric assay for monitoring adenosine 5'-monophosphate production.

    Science.gov (United States)

    First, Eric A

    2015-08-15

    A number of biologically important enzymes release adenosine 5'-monophosphate (AMP) as a product, including aminoacyl-tRNA synthetases, cyclic AMP (cAMP) phosphodiesterases, ubiquitin and ubiquitin-like ligases, DNA ligases, coenzyme A (CoA) ligases, polyA deadenylases, and ribonucleases. In contrast to the abundance of assays available for monitoring the conversion of adenosine 5'-triphosphate (ATP) to ADP, there are relatively few assays for monitoring the conversion of ATP (or cAMP) to AMP. In this article, we describe a homogeneous assay that continuously monitors the production of AMP. Specifically, we have coupled the conversion of AMP to inosine 5'-monophosphate (IMP) (by AMP deaminase) to the oxidation of IMP (by IMP dehydrogenase). This results in the reduction of oxidized nicotine adenine dinucleotide (NAD(+)) to reduced nicotine adenine dinucleotide (NADH), allowing AMP formation to be monitored by the change in the absorbance at 340 nm. Changes in AMP concentrations of 5 μM or more can be reliably detected. The ease of use and relatively low expense make the AMP assay suitable for both high-throughput screening and kinetic analyses. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Specific Interactions of Antitumor Metallocenes with Deoxydinucleoside Monophosphates

    Science.gov (United States)

    Eberle, Rahel P.; Hari, Yvonne; Schürch, Stefan

    2017-09-01

    Bent metallocenes Cp2MCl2 (M = Ti, V, Nb, Mo) are known to exhibit cytotoxic activity against a variety of cancer types. Though the mechanism of action is not fully understood yet, the accumulation of the metal ions in the nucleus points towards DNA as one of the primary targets. A set of eight deoxydinucleoside monophosphates was used to study the adduct yields with metallocenes and cisplatin. The binding affinities are reflected by the relative intensities of the adducts and were found to follow the order of Pt > V > Ti > Mo (no adducts were detected with Nb). High-resolution tandem mass spectrometry was applied to locate the binding patterns in the deoxydinucleoside monophosphates. Whereas cisplatin binds to the soft nitrogen atoms in the purine nucleobases, the metallocenes additionally interact with the hard phosphate oxygen, which is in good agreement with the hard and soft (Lewis) acids and bases (HSAB) concept. However, the binding specificities were found to be unique for each metallocene. The hard Lewis acids titanium and vanadium predominantly bind to the deprotonated phosphate oxygen, whereas molybdenum, an intermediate Lewis acid, preferentially interacts with the nucleobases. Nucleobases comprise alternative binding sites for titanium and vanadium, presumably oxygen atoms for the first and nitrogen atoms for the latter. In summary, the intrinsic binding behavior of the different metallodrugs is reflected by the gas-phase dissociation of the adducts. Consequently, MS/MS can provide insights into therapeutically relevant interactions between metallodrugs and their cellular targets. [Figure not available: see fulltext.

  12. Luteinizing hormone signaling phosphorylates and activates the cyclic GMP phosphodiesterase PDE5 in mouse ovarian follicles, contributing an additional component to the hormonally induced decrease in cyclic GMP that reinitiates meiosis.

    Science.gov (United States)

    Egbert, Jeremy R; Yee, Siu-Pok; Jaffe, Laurinda A

    2018-03-01

    Prior to birth, oocytes within mammalian ovarian follicles initiate meiosis, but then arrest in prophase until puberty, when with each reproductive cycle, one or more follicles are stimulated by luteinizing hormone (LH) to resume meiosis in preparation for fertilization. Within preovulatory follicles, granulosa cells produce high levels of cGMP, which diffuses into the oocyte to maintain meiotic arrest. LH signaling restarts meiosis by rapidly lowering the levels of cGMP in the follicle and oocyte. Part of this decrease is mediated by the dephosphorylation and inactivation the NPR2 guanylyl cyclase in response to LH, but the mechanism for the remainder of the cGMP decrease is unknown. At least one cGMP phosphodiesterase, PDE5, is activated by LH signaling, which would contribute to lowering cGMP. PDE5 exhibits increased cGMP-hydrolytic activity when phosphorylated on serine 92, and we recently demonstrated that LH signaling phosphorylates PDE5 on this serine and increases its activity in rat follicles. To test the extent to which this mechanism contributes to the cGMP decrease that restarts meiosis, we generated a mouse line in which serine 92 was mutated to alanine (Pde5-S92A), such that it cannot be phosphorylated. Here we show that PDE5 phosphorylation is required for the LH-induced increase in cGMP-hydrolytic activity, but that this increase has only a modest effect on the LH-induced cGMP decrease in mouse follicles, and does not affect the timing of meiotic resumption. Though we show that the activation of PDE5 is among the mechanisms contributing to the cGMP decrease, these results suggest that another cGMP phosphodiesterase is also activated by LH signaling. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Monophosphate end groups produced in radiation induced strand breakage in DNA

    International Nuclear Information System (INIS)

    Kay, E.; Ward, J.F.

    1976-01-01

    A solution of DNA was gamma-irradiated and treated with monophosphatase for studies on the amount of inorganic phosphate released as a function of time. Studies were also conducted on: effect of alkali on yield of monophosphate end groups; induction of DNA strand breaks by treatment with DNAase; initial G values for monophosphate termini; and effect of alkali on radioinduced DNA damage

  14. Now that you want to take your HIV/AIDS vaccine/biological product research concept into the clinic: what are the "cGMP"?

    Science.gov (United States)

    Sheets, Rebecca L; Rangavajhula, Vijaya; Pullen, Jeffrey K; Butler, Chris; Mehra, Vijay; Shapiro, Stuart; Pensiero, Michael

    2015-04-08

    The Division of AIDS Vaccine Research Program funds the discovery and development of HIV/AIDS vaccine candidates. Basic researchers, having discovered a potential vaccine in the laboratory, next want to take that candidate into the clinic to test the concept in humans, to see if it translates. Many of them have heard of "cGMP" and know that they are supposed to make a "GMP product" to take into the clinic, but often they are not very familiar with what "cGMP" means and why these good practices are so important. As members of the Vaccine Translational Research Branch, we frequently get asked "can't we use the material we made in the lab in the clinic?" or "aren't Phase 1 studies exempt from cGMP?" Over the years, we have had many experiences where researchers or their selected contract manufacturing organizations have not applied an appropriate degree of compliance with cGMP suitable for the clinical phase of development. We share some of these experiences and the lessons learned, along with explaining the importance of cGMP, just what cGMP means, and what they can assure, in an effort to de-mystify this subject and facilitate the rapid and safe translational development of HIV vaccines. Published by Elsevier Ltd.

  15. Purine 3':5'-cyclic nucleotides with the nucleobase in a syn orientation: cAMP, cGMP and cIMP.

    Science.gov (United States)

    Řlepokura, Katarzyna Anna

    2016-06-01

    Purine 3':5'-cyclic nucleotides are very well known for their role as the secondary messengers in hormone action and cellular signal transduction. Nonetheless, their solid-state conformational details still require investigation. Five crystals containing purine 3':5'-cyclic nucleotides have been obtained and structurally characterized, namely adenosine 3':5'-cyclic phosphate dihydrate, C10H12N5O6P·2H2O or cAMP·2H2O, (I), adenosine 3':5'-cyclic phosphate 0.3-hydrate, C10H12N5O6P·0.3H2O or cAMP·0.3H2O, (II), guanosine 3':5'-cyclic phosphate pentahydrate, C10H12N5O7P·5H2O or cGMP·5H2O, (III), sodium guanosine 3':5'-cyclic phosphate tetrahydrate, Na(+)·C10H11N5O7P(-)·4H2O or Na(cGMP)·4H2O, (IV), and sodium inosine 3':5'-cyclic phosphate tetrahydrate, Na(+)·C10H10N4O7P(-)·4H2O or Na(cIMP)·4H2O, (V). Most of the cyclic nucleotide zwitterions/anions [two from four cAMP present in total in (I) and (II), cGMP in (III), cGMP(-) in (IV) and cIMP(-) in (V)] are syn conformers about the N-glycosidic bond, and this nucleobase arrangement is accompanied by Crib-H...Npur hydrogen bonds (rib = ribose and pur = purine). The base orientation is tuned by the ribose pucker. An analysis of data obtained from the Cambridge Structural Database made in the context of syn-anti conformational preferences has revealed that among the syn conformers of various purine nucleotides, cyclic nucleotides and dinucleotides predominate significantly. The interactions stabilizing the syn conformation have been indicated. The inter-nucleotide contacts in (I)-(V) have been systematized in terms of the chemical groups involved. All five structures display three-dimensional hydrogen-bonded networks.

  16. The impact of cGMP compliance on consumer confidence in dietary supplement products

    International Nuclear Information System (INIS)

    Crowley, Richard; FitzGerald, Libby Harvey

    2006-01-01

    The FDA estimates that US citizens spend more than $ 8.5 billion a year on dietary supplements and world wide the market is estimated at more than $ 60 billion. However, although a majority of consumers express confidence in the safety of these products, 74% believe the government should be more involved in ensuring that these products are safe and efficacious. Recent regulatory initiatives such as the imminent adoption of cGMPs for dietary supplements in the US, implementation of cGMPs in Canada and the recent EU dietary supplement initiative represent legislative and industry response to public clamor for more comprehensive oversight of dietary supplements. Regardless of mandated practices, the majority of dietary supplement manufacturers have done an excellent job of protecting the safety and quality of their products. The promulgation of these cGMPs will help ensure consumers that equal standards are followed throughout the industry. For some companies with established processes based on existing food or pharmaceutical cGMP regulations, the transition will be relatively painless while, for many, it will represent a significant increase in the level of documentation and testing. However, consumers deserve and demand that products meet standards for safety and quality and the implementation of cGMPs for these products are an important first step. Although the cGMPs are designed to ensure products are safe from a standpoint of identity, purity, quality, strength and composition, they do not address preclinical or clinical testing of ingredients for safety or efficacy. This would involve ingredients meeting the requirements of Generally Recognized as Safe (GRAS) status or going through the New Dietary Ingredient (NDI) process

  17. A simplified radioimmunoassay of adenosine-3':5'-monophosphate

    International Nuclear Information System (INIS)

    Katoh, Yoshiki; Takezawa, Junichi; Suzuki, Morio; Kuninaka, Akira; Yoshino, Hiroshi

    1975-01-01

    Dextran-coated charcoal was proved to be able to separate free adenosine-3':5'monophosphate (cAMP) from antibody-bound cAMP. Only free cAMO was adsorbed on dextran-coated charcoal within 1 min after contacting the charcoal. In a reaction mixture of cAMP and anti-cAMP-plasma, most of antibody-bound cAMP had not been adsorbed 4 min after contacting. The data obtained were found to be almost the same as the data of another experiment using cellulose ester filter separation technique. Thus, dextran-coated charcoal could be employed to simplify the radioimmunoassay of cAMP. (author)

  18. Guanylin peptides: cyclic GMP signaling mechanisms

    Directory of Open Access Journals (Sweden)

    Forte L.R.

    1999-01-01

    Full Text Available Guanylate cyclases (GC serve in two different signaling pathways involving cytosolic and membrane enzymes. Membrane GCs are receptors for guanylin and atriopeptin peptides, two families of cGMP-regulating peptides. Three subclasses of guanylin peptides contain one intramolecular disulfide (lymphoguanylin, two disulfides (guanylin and uroguanylin and three disulfides (E. coli stable toxin, ST. The peptides activate membrane receptor-GCs and regulate intestinal Cl- and HCO3- secretion via cGMP in target enterocytes. Uroguanylin and ST also elicit diuretic and natriuretic responses in the kidney. GC-C is an intestinal receptor-GC for guanylin and uroguanylin, but GC-C may not be involved in renal cGMP pathways. A novel receptor-GC expressed in the opossum kidney (OK-GC has been identified by molecular cloning. OK-GC cDNAs encode receptor-GCs in renal tubules that are activated by guanylins. Lymphoguanylin is highly expressed in the kidney and heart where it may influence cGMP pathways. Guanylin and uroguanylin are highly expressed in intestinal mucosa to regulate intestinal salt and water transport via paracrine actions on GC-C. Uroguanylin and guanylin are also secreted from intestinal mucosa into plasma where uroguanylin serves as an intestinal natriuretic hormone to influence body Na+ homeostasis by endocrine mechanisms. Thus, guanylin peptides control salt and water transport in the kidney and intestine mediated by cGMP via membrane receptors with intrinsic guanylate cyclase activity.

  19. Molecular methods for the study of signal transduction in plants

    KAUST Repository

    Irving, Helen R.; Gehring, Christoph A

    2013-01-01

    as well as at the systems level where transcriptomics and particularly phosphoproteomics afford a window into complex biological responses. Here we review the role of the cyclic nucleotides cAMP and cGMP in plant signal transduction as well

  20. The Role of Aquaporin 1 Activated by cGMP in Myocardial Edema Caused by Cardiopulmonary Bypass in Sheep

    Directory of Open Access Journals (Sweden)

    Fang-bao Ding

    2013-11-01

    Full Text Available Background/Aims: Most cardiac procedures involve the use of cardiopulmonary bypass (CPB, which pumps oxygenated blood to the body while the heart and lungs are isolated. CPB can cause profound alterations V in the homeostasis of physiological fluids, which often results in myocardial edema. In our study, we used sheep CPB model of in vivo and in vitro to assess the relationship between cGMP and AQP1 during CPB. Methods: ODQ, a specific inhibitor of soluble guanylate cyclase (sGC, was used to treat the CPB animals or cardiomyocytes. Left ventricular function of each group was determined by pressure-volume system. Water content of myocardial tissue was assessed by dry-wet weight, and cardiomyocytes water permeability was also calculated. The concentration of cGMP was determined by Radioimmunoassay (RIA. mRNA and protein expression of AQP1 were detected by real-time PCR and western blot, respectively. Results: The relative expression level of AQP1 mRNA and protein at each time point (0, 6, 12, 24 or 48 h after CPB was significantly increased (1.18-fold at 12 h, 1.77-fold at 24 h and 2.18-fold at 48h compared with each sham group, the protein expression of AQP1 also showed a rising trend after CPB. The degree of myocardial edema (75.1% at 12 h, 79.3% at 24 h and 81.0% at 48h increased following the CPB surgery. The mRNA expression level of AQP1 was significantly decreased by 39.7% (pin vitro experiments showed the same changing trends as in vivo. Conclusion: cGMP pathway controls water channels and then affects water intake during CPB through an AQP1-mediated pathway.

  1. Arginine induces GH gene expression by activating NOS/NO signaling in rat isolated hemi-pituitaries

    Directory of Open Access Journals (Sweden)

    S.C.F. Olinto

    2012-11-01

    Full Text Available The amino acid arginine (Arg is a recognized secretagogue of growth hormone (GH, and has been shown to induce GH gene expression. Arg is the natural precursor of nitric oxide (NO, which is known to mediate many of the effects of Arg, such as GH secretion. Arg was also shown to increase calcium influx in pituitary cells, which might contribute to its effects on GH secretion. Although the mechanisms involved in the effects of Arg on GH secretion are well established, little is known about them regarding the control of GH gene expression. We investigated whether the NO pathway and/or calcium are involved in the effects of Arg on GH gene expression in rat isolated pituitaries. To this end, pituitaries from approximately 170 male Wistar rats (~250 g were removed, divided into two halves, pooled (three hemi-pituitaries and incubated or not with Arg, as well as with different pharmacological agents. Arg (71 mM, the NO donor sodium nitroprusside (SNP, 1 and 0.1 mM and a cyclic guanosine monophosphate (cGMP analogue (8-Br-cGMP, 1 mM increased GH mRNA expression 60 min later. The NO acceptor hemoglobin (0.3 µM blunted the effect of SNP, and the combined treatment with Arg and L-NAME (a NO synthase (NOS inhibitor, 55 mM abolished the stimulatory effect of Arg on GH gene expression. The calcium channel inhibitor nifedipine (3 µM also abolished Arg-induced GH gene expression. The present study shows that Arg directly induces GH gene expression in hemi-pituitaries isolated from rats, excluding interference from somatostatinergic neurons, which are supposed to be inhibited by Arg. Moreover, the data demonstrate that the NOS/NO signaling pathway and calcium mediate the Arg effects on GH gene expression.

  2. Arginine induces GH gene expression by activating NOS/NO signaling in rat isolated hemi-pituitaries

    Energy Technology Data Exchange (ETDEWEB)

    Olinto, S.C.F. [Faculdade de Ciências Integradas do Pontal, Universidade Federal de Uberlândia, Ituiutaba, MG (Brazil); Adrião, M.G. [Departamento de Morfologia e Fisiologia, Universidade Federal Rural de Pernambuco, Recife, PE (Brazil); Castro-Barbosa, T.; Goulart-Silva, F.; Nunes, M.T. [Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP (Brazil)

    2012-06-01

    The amino acid arginine (Arg) is a recognized secretagogue of growth hormone (GH), and has been shown to induce GH gene expression. Arg is the natural precursor of nitric oxide (NO), which is known to mediate many of the effects of Arg, such as GH secretion. Arg was also shown to increase calcium influx in pituitary cells, which might contribute to its effects on GH secretion. Although the mechanisms involved in the effects of Arg on GH secretion are well established, little is known about them regarding the control of GH gene expression. We investigated whether the NO pathway and/or calcium are involved in the effects of Arg on GH gene expression in rat isolated pituitaries. To this end, pituitaries from approximately 170 male Wistar rats (∼250 g) were removed, divided into two halves, pooled (three hemi-pituitaries) and incubated or not with Arg, as well as with different pharmacological agents. Arg (71 mM), the NO donor sodium nitroprusside (SNP, 1 and 0.1 mM) and a cyclic guanosine monophosphate (cGMP) analogue (8-Br-cGMP, 1 mM) increased GH mRNA expression 60 min later. The NO acceptor hemoglobin (0.3 µM) blunted the effect of SNP, and the combined treatment with Arg and L-NAME (an NO synthase (NOS) inhibitor, 55 mM) abolished the stimulatory effect of Arg on GH gene expression. The calcium channel inhibitor nifedipine (3 µM) also abolished Arg-induced GH gene expression. The present study shows that Arg directly induces GH gene expression in hemi-pituitaries isolated from rats, excluding interference from somatostatinergic neurons, which are supposed to be inhibited by Arg. Moreover, the data demonstrate that the NOS/NO signaling pathway and calcium mediate the Arg effects on GH gene expression.

  3. Arginine induces GH gene expression by activating NOS/NO signaling in rat isolated hemi-pituitaries

    International Nuclear Information System (INIS)

    Olinto, S.C.F.; Adrião, M.G.; Castro-Barbosa, T.; Goulart-Silva, F.; Nunes, M.T.

    2012-01-01

    The amino acid arginine (Arg) is a recognized secretagogue of growth hormone (GH), and has been shown to induce GH gene expression. Arg is the natural precursor of nitric oxide (NO), which is known to mediate many of the effects of Arg, such as GH secretion. Arg was also shown to increase calcium influx in pituitary cells, which might contribute to its effects on GH secretion. Although the mechanisms involved in the effects of Arg on GH secretion are well established, little is known about them regarding the control of GH gene expression. We investigated whether the NO pathway and/or calcium are involved in the effects of Arg on GH gene expression in rat isolated pituitaries. To this end, pituitaries from approximately 170 male Wistar rats (∼250 g) were removed, divided into two halves, pooled (three hemi-pituitaries) and incubated or not with Arg, as well as with different pharmacological agents. Arg (71 mM), the NO donor sodium nitroprusside (SNP, 1 and 0.1 mM) and a cyclic guanosine monophosphate (cGMP) analogue (8-Br-cGMP, 1 mM) increased GH mRNA expression 60 min later. The NO acceptor hemoglobin (0.3 µM) blunted the effect of SNP, and the combined treatment with Arg and L-NAME (an NO synthase (NOS) inhibitor, 55 mM) abolished the stimulatory effect of Arg on GH gene expression. The calcium channel inhibitor nifedipine (3 µM) also abolished Arg-induced GH gene expression. The present study shows that Arg directly induces GH gene expression in hemi-pituitaries isolated from rats, excluding interference from somatostatinergic neurons, which are supposed to be inhibited by Arg. Moreover, the data demonstrate that the NOS/NO signaling pathway and calcium mediate the Arg effects on GH gene expression

  4. Cyclic adenosine 3:5-monophosphate binding proteins in Hartmannella culbertsoni

    International Nuclear Information System (INIS)

    Verma, A.K.; Krishna Murti, C.R.

    1976-01-01

    When 100, 000 g supernatant fractions of homogenates of Hartmannella culbertsoni were incubated with ('- 3 H)-cyclic adenosine 3 : 5 monophosphate and passed through a sephadex G-100 column, radioactivity appeared with protein fractions eluted after the void colume. About 75% radioactivity bound to these fractions was recovered as cyclic adenosine 3 : 5 monophosphate. Unlabelled cAMP diluted the amount of radioactivity bound. Adenosine, deoxyadenosine, 5-AMP, 3-AMP, ADP and ATP did not inhibit binding. (author)

  5. Method of preparing tritium-labelled thymidine-5'-monophosphates of high specific activity

    International Nuclear Information System (INIS)

    Filip, J.; Vesely, J.; Cihak, A.

    1976-01-01

    A method is described of preparing thymidine-5'-monophosphates labelled with tritium of high specific activity based on enzyme synthesis in vitro. Phosphorylation was carried out using the catalytic effect of an enzyme contained in the supernatant fraction prepared from Yoshida ascites carcinoma in rats. The course of the enzyme reaction can be controlled by the concentration of the individual reaction mixture components. The method described allows obtaining thymidine-5'-monophosphate of radiochemical purity better than 95%. (J.B.)

  6. Deoxypyrimidine monophosphate bypass therapy for thymidine kinase 2 deficiency.

    Science.gov (United States)

    Garone, Caterina; Garcia-Diaz, Beatriz; Emmanuele, Valentina; Lopez, Luis C; Tadesse, Saba; Akman, Hasan O; Tanji, Kurenai; Quinzii, Catarina M; Hirano, Michio

    2014-08-01

    Autosomal recessive mutations in the thymidine kinase 2 gene (TK2) cause mitochondrial DNA depletion, multiple deletions, or both due to loss of TK2 enzyme activity and ensuing unbalanced deoxynucleotide triphosphate (dNTP) pools. To bypass Tk2 deficiency, we administered deoxycytidine and deoxythymidine monophosphates (dCMP+dTMP) to the Tk2 H126N (Tk2(-/-)) knock-in mouse model from postnatal day 4, when mutant mice are phenotypically normal, but biochemically affected. Assessment of 13-day-old Tk2(-/-) mice treated with dCMP+dTMP 200 mg/kg/day each (Tk2(-/-200dCMP/) (dTMP)) demonstrated that in mutant animals, the compounds raise dTTP concentrations, increase levels of mtDNA, ameliorate defects of mitochondrial respiratory chain enzymes, and significantly prolong their lifespan (34 days with treatment versus 13 days untreated). A second trial of dCMP+dTMP each at 400 mg/kg/day showed even greater phenotypic and biochemical improvements. In conclusion, dCMP/dTMP supplementation is the first effective pharmacologic treatment for Tk2 deficiency. © 2014 The Authors. Published under the terms of the CC BY 4.0 license.

  7. The fate of H atom adducts to 3'-uridine monophosphate.

    Science.gov (United States)

    Wang, Ran; Zhang, Ru Bo; Eriksson, Leif A

    2010-07-29

    The stabilities of the adducts deriving from H free radical addition to the O2, O4, and C5 positions of 3'-uridine monophosphate (3'UMP) are studied by the hybrid density functional B3LYP approach. Upon H atom addition at the O2 position, a concerted low-barrier proton-transfer process will initially occur, followed by the potential ruptures of the N-glycosidic or beta-phosphate bonds. The rupture barriers are strongly influenced by the rotational configuration of the phosphate group at the 3' terminal, and are influenced by bulk solvation effects. The O4-H adduct has the highest thermal stability, as the localization of the unpaired electron does not enable cleavage of either the C1'-N1 or the C3'-O(P) bonds. For the most stable adduct, with H atom added to the C5 position, the rate-controlled step is the H2'a abstraction by the C6 radical site, after which the subsequent strand rupture reactions proceed with low barriers. The main unpaired electron densities are presented for the transient species. Combined with previous results, it is concluded that the H atom adducts are more facile to drive the strand scission rather than N-glycosidic bond ruptures within the nucleic acid bases.

  8. Characterization of a monoclonal antibody to thymidine glycol monophosphate

    International Nuclear Information System (INIS)

    Chen, B.X.; Hubbard, K.; Ide, H.; Wallace, S.S.; Erlanger, B.F.

    1990-01-01

    A monoclonal antibody specific for thymine glycol (TG) in irradiated or OsO4-treated DNA was obtained by immunizing with thymidine glycol monophosphate (TMP-glycol) conjugated to bovine serum albumin by a carbodiimide procedure. Screening by dot-immunobinding and enzyme-linked immunosorbant assay (ELISA) procedures gave eight clones that bound OsO4- treated DNA. One of them, 2.6F.6B.6C, an IgG2a kappa, was characterized further. Hapten inhibition studies with OsO4-treated DNA showed that the antibody was specific for TMP-glycol. Among the various inhibitors tested, inhibition was in the order TMP-glycol greater than 5,6-dihydrothymidine phosphate greater than TMP greater than thymidine glycol greater than TG. Inhibition by 5,6-dihydrothymidine, thymidine, thymine, AMP, and CMP was negligible. In OsO4-treated DNA, as few as 0.5 TG per 10,000 bp were detectable by direct ELISA. Inhibition assays could detect as few as 1.5 TG per 10,000 bp. The antibody was equally reactive with native or denatured DNA containing TG. Among the X-irradiated homopolymers dC, dA, dG, and dT, only dT reacted with the antibody. Using an ELISA, the antibody could detect damage in irradiated DNA at the level of 20 Gy. Thus the antibody is of potential use in assays for DNA damage caused by X rays or other agents that damage DNA by free radical interactions

  9. Direct interaction of the inhibitory gamma-subunit of Rod cGMP phosphodiesterase (PDE6) with the PDE6 GAFa domains.

    Science.gov (United States)

    Muradov, Khakim G; Granovsky, Alexey E; Schey, Kevin L; Artemyev, Nikolai O

    2002-03-26

    Retinal rod and cone cGMP phosphodiesterases (PDE6 family) function as the effector enzyme in the vertebrate visual transduction cascade. The activity of PDE6 catalytic subunits is controlled by the Pgamma-subunits. In addition to the inhibition of cGMP hydrolysis at the catalytic sites, Pgamma is known to stimulate a noncatalytic binding of cGMP to the regulatory GAFa-GAFb domains of PDE6. The latter role of Pgamma has been attributed to its polycationic region. To elucidate the structural basis for the regulation of cGMP binding to the GAF domains of PDE6, a photoexcitable peptide probe corresponding to the polycationic region of Pgamma, Pgamma-21-45, was specifically cross-linked to rod PDE6alphabeta. The site of Pgamma-21-45 cross-linking was localized to Met138Gly139 within the PDE6alpha GAFa domain using mass spectrometric analysis. Chimeras between PDE5 and cone PDE6alpha', containing GAFa and/or GAFb domains of PDE6alpha' have been generated to probe a potential role of the GAFb domains in binding to Pgamma. Analysis of the inhibition of the PDE5/PDE6alpha' chimeras by Pgamma supported the role of PDE6 GAFa but not GAFb domains in the interaction with Pgamma. Our results suggest that a direct binding of the polycationic region of Pgamma to the GAFa domains of PDE6 may lead to a stabilization of the noncatalytic cGMP-binding sites.

  10. The search for mutations in the gene for the beta subunit of the cGMP phosphodiesterase (PDEB) in patients with autosomal recessive retinitis pigmentosa

    DEFF Research Database (Denmark)

    Riess, O; Noerremoelle, A; Weber, B

    1992-01-01

    The finding of a mutation in the beta subunit of the cyclic GMP (cGMP) phosphodiesterase gene causing retinal degeneration in mice (the Pdeb gene) prompted a search for disease-causing mutations in the human phosphodiesterase gene (PDEB gene) in patients with retinitis pigmentosa. All 22 exons...

  11. Identification of the gamma subunit-interacting residues on photoreceptor cGMP phosphodiesterase, PDE6alpha '.

    Science.gov (United States)

    Granovsky, A E; Artemyev, N O

    2000-12-29

    Photoreceptor cGMP phosphodiesterase (PDE6) is the effector enzyme in the G protein-mediated visual transduction cascade. In the dark, the activity of PDE6 is shut off by the inhibitory gamma subunit (Pgamma). Chimeric proteins between cone PDE6alpha' and cGMP-binding and cGMP-specific PDE (PDE5) have been constructed and expressed in Sf9 cells to study the mechanism of inhibition of PDE6 catalytic activity by Pgamma. Substitution of the segment PDE5-(773-820) by the corresponding PDE6alpha'-(737-784) sequence in the wild-type PDE5 or in a PDE5/PDE6alpha' chimera containing the catalytic domain of PDE5 results in chimeric enzymes capable of inhibitory interaction with Pgamma. The catalytic properties of the chimeric PDEs remained similar to those of PDE5. Ala-scanning mutational analysis of the Pgamma-binding region, PDE6alpha'-(750-760), revealed PDE6alpha' residues essential for the interaction. The M758A mutation markedly impaired and the Q752A mutation moderately impaired the inhibition of chimeric PDE by Pgamma. The analysis of the catalytic properties of mutant PDEs and a model of the PDE6 catalytic domain suggest that residues Met(758) and Gln(752) directly bind Pgamma. A model of the PDE6 catalytic site shows that PDE6alpha'-(750-760) forms a loop at the entrance to the cGMP-binding pocket. Binding of Pgamma to Met(758) would effectively block access of cGMP to the catalytic cavity, providing a structural basis for the mechanism of PDE6 inhibition.

  12. Moonlighting kinases with guanylate cyclase activity can tune regulatory signal networks

    KAUST Repository

    Irving, Helen R.; Kwezi, Lusisizwe; Wheeler, Janet I.; Gehring, Christoph A

    2012-01-01

    Guanylate cyclase (GC) catalyzes the formation of cGMP and it is only recently that such enzymes have been characterized in plants. One family of plant GCs contains the GC catalytic center encapsulated within the intracellular kinase domain of leucine rich repeat receptor like kinases such as the phytosulfokine and brassinosteroid receptors. In vitro studies show that both the kinase and GC domain have catalytic activity indicating that these kinase-GCs are examples of moonlighting proteins with dual catalytic function. The natural ligands for both receptors increase intracellular cGMP levels in isolated mesophyll protoplast assays suggesting that the GC activity is functionally relevant. cGMP production may have an autoregulatory role on receptor kinase activity and/or contribute to downstream cell expansion responses. We postulate that the receptors are members of a novel class of receptor kinases that contain functional moonlighting GC domains essential for complex signaling roles.

  13. Moonlighting kinases with guanylate cyclase activity can tune regulatory signal networks

    KAUST Repository

    Irving, Helen R.

    2012-02-01

    Guanylate cyclase (GC) catalyzes the formation of cGMP and it is only recently that such enzymes have been characterized in plants. One family of plant GCs contains the GC catalytic center encapsulated within the intracellular kinase domain of leucine rich repeat receptor like kinases such as the phytosulfokine and brassinosteroid receptors. In vitro studies show that both the kinase and GC domain have catalytic activity indicating that these kinase-GCs are examples of moonlighting proteins with dual catalytic function. The natural ligands for both receptors increase intracellular cGMP levels in isolated mesophyll protoplast assays suggesting that the GC activity is functionally relevant. cGMP production may have an autoregulatory role on receptor kinase activity and/or contribute to downstream cell expansion responses. We postulate that the receptors are members of a novel class of receptor kinases that contain functional moonlighting GC domains essential for complex signaling roles.

  14. Adenosine monophosphate-activated protein kinase modulates the activated phenotype of hepatic stellate cells.

    Science.gov (United States)

    Caligiuri, Alessandra; Bertolani, Cristiana; Guerra, Cristina Tosti; Aleffi, Sara; Galastri, Sara; Trappoliere, Marco; Vizzutti, Francesco; Gelmini, Stefania; Laffi, Giacomo; Pinzani, Massimo; Marra, Fabio

    2008-02-01

    Adiponectin limits the development of liver fibrosis and activates adenosine monophosphate-activated protein kinase (AMPK). AMPK is a sensor of the cellular energy status, but its possible modulation of the fibrogenic properties of hepatic stellate cells (HSCs) has not been established. In this study, we investigated the role of AMPK activation in the biology of activated human HSCs. A time-dependent activation of AMPK was observed in response to a number of stimuli, including globular adiponectin, 5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside (AICAR), or metformin. All these compounds significantly inhibited platelet-derived growth factor (PDGF)-stimulated proliferation and migration of human HSCs and reduced the secretion of monocyte chemoattractant protein-1. In addition, AICAR limited the secretion of type I procollagen. Knockdown of AMPK by gene silencing increased the mitogenic effects of PDGF, confirming the negative modulation exerted by this pathway on HSCs. AMPK activation did not reduce PDGF-dependent activation of extracellular signal-regulated kinase (ERK) or Akt at early time points, whereas a marked inhibition was observed 24 hours after addition of PDGF, reflecting a block in cell cycle progression. In contrast, AICAR blocked short-term phosphorylation of ribosomal S6 kinase (p70(S6K)) and 4E binding protein-1 (4EBP1), 2 downstream effectors of the mammalian target of rapamycin (mTOR) pathway, by PDGF. The ability of interleukin-a (IL-1) to activate nuclear factor kappa B (NF-kappaB) was also reduced by AICAR. Activation of AMPK negatively modulates the activated phenotype of HSCs.

  15. Nitric oxide signaling depends on biotin in Jurkat human lymphoma cells.

    Science.gov (United States)

    Rodriguez-Melendez, Rocio; Zempleni, Janos

    2009-03-01

    Biotin affects gene expression through a diverse array of cell signaling pathways. Previous studies provided evidence that cGMP-dependent signaling also depends on biotin, but the mechanistic sequence of cGMP regulation by biotin is unknown. Here we tested the hypothesis that the effects of biotin in cGMP-dependent cell signaling are mediated by nitric oxide (NO). Human lymphoid (Jurkat) cells were cultured in media containing deficient (0.025 nmol/L), physiological (0.25 nmol/L), and pharmacological (10 nmol/L) concentrations of biotin for 5 wk. Both levels of intracellular biotin and NO exhibited a dose-dependent relationship in regard to biotin concentrations in culture media. Effects of biotin on NO levels were disrupted by the NO synthase (NOS) inhibitor N-monomethyl-arginine. Biotin-dependent production of NO was linked with biotin-dependent expression of endothelial and neuronal NOS, but not inducible NOS. Previous studies revealed that NO is an activator of guanylate cyclase. Consistent with these previous observations, biotin-dependent generation of NO increased the abundance of cGMP in Jurkat cells. Finally, the biotin-dependent generation of cGMP increased protein kinase G activity. Collectively, the results of this study are consistent with the hypothesis that biotin-dependent cGMP signaling in human lymphoid cells is mediated by NO.

  16. Environmental Monitoring Trendy Study for cGMP Tc-99m Production at Nuclear Malaysia for the Year 2014

    International Nuclear Information System (INIS)

    Bohari Yaacob; Manisah Saedon; Fazliana Mohd Saaya

    2015-01-01

    Nuclear Malaysia is engaged to produce quality promising Tc-99m generator for the medical usage which is carried out at the production area of block 21, compromise of grade A, C and D clean room. This study applies to the trending of the environmental monitoring of the clean room for the year 2014 in order to ensure that the clean room complies with the cGMP requirement in term of environmental specification which is room temperature, relative humidity, room pressure and particle count. The room temperature specification is 22±2 degree Celsius and result showed that both preparation and pharmaceutical room are within the limit. But it was found that the result from gowning and degowning room temperature was more than 24 degree Celsius. Whereby, result for average percentage relative humidity of the gowning, preparation, pharmaceutical and degowning rooms were found 51 %.±7, 60 %±4, 61 %±5, 61 %±5 and 58 %±4 respectively are out off the range (< 60 %). The target level of pressure differential for all rooms is 1.5 mmH 2 O and only pharmaceutical room was found not within the target with the reading of 3.3 mmH 2 O±0.5. Result for 16 location showed that particle counts which particles size 5.0 μm were within the limit namely ≤ 2000/ m 3 except location number 21 and 18 in the pharmaceutical room and location number 23 in the degowning rooms were exceeding more than 2000/ m 3 for the month of July 2014. However results for all location particles size of 0.5 μm, were within specification (≤350000/ m 3 ). All location of all rooms with class C grade is within limit that is < 50 CFU of microbiology growth except location number 8, 9 and 10 of preparation room whereby this location is a class A grade. Generally, the environmental monitoring result for the clean room are satisfactory for the year 2014 since all the final product of all batches has passed the sterility and endotoxin test. In conclusion, Malaysian Nuclear Agency had fulfills the cGMP requirement

  17. Gold Core Mesoporous Organosilica Shell Degradable Nanoparticles for Two-Photon Imaging and Gemcitabine Monophosphate Delivery

    KAUST Repository

    Rhamani, Saher; Chaix, Arnaud; Aggad, Dina; Hoang, Phuong Mai; Moosa, Basem; Garcia, Marcel; Gary-Bobo, Magali; Charnay, Clarence; Almalik, Abdulaziz; Durand, Jean-Olivier; Khashab, Niveen M.

    2017-01-01

    The synthesis of gold core degradable mesoporous organosilica shell nanoparticles is described. The nanopaticles were very efficient for two-photon luminescence imaging of cancer cells and for in vitro gemcitabine monophosphate delivery, allowing promising theranostic applications in the nanomedicine field.

  18. Gold Core Mesoporous Organosilica Shell Degradable Nanoparticles for Two-Photon Imaging and Gemcitabine Monophosphate Delivery

    KAUST Repository

    Rhamani, Saher

    2017-09-12

    The synthesis of gold core degradable mesoporous organosilica shell nanoparticles is described. The nanopaticles were very efficient for two-photon luminescence imaging of cancer cells and for in vitro gemcitabine monophosphate delivery, allowing promising theranostic applications in the nanomedicine field.

  19. Short-term treatment with budesonide does not improve hyperresponsiveness to adenosine 5 '-monophosphate in COPD

    NARCIS (Netherlands)

    Rutgers, [No Value; Koeter, GH; van der Mark, TW; Postma, DS

    The role of inhaled corticosteroids in the treatment of chronic obstructive pulmonary disease (COPD) is unclear. We investigated the effects of budesonide on airway hyperresponsiveness (AHR) to methacholine (MCh) and adenosine 5'-monophosphate (AMP), to which we hypothesized the existence of greater

  20. 3-cyanoindole-based inhibitors of inosine monophosphate dehydrogenase: synthesis and initial structure-activity relationships.

    Science.gov (United States)

    Dhar, T G Murali; Shen, Zhongqi; Gu, Henry H; Chen, Ping; Norris, Derek; Watterson, Scott H; Ballentine, Shelley K; Fleener, Catherine A; Rouleau, Katherine A; Barrish, Joel C; Townsend, Robert; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2003-10-20

    A series of novel small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH), based upon a 3-cyanoindole core, were explored. IMPDH catalyzes the rate determining step in guanine nucleotide biosynthesis and is a target for anticancer, immunosuppressive and antiviral therapy. The synthesis and the structure-activity relationships (SAR), derived from in vitro studies, for this new series of inhibitors is given.

  1. A survey of cyclic replacements for the central diamide moiety of inhibitors of inosine monophosphate dehydrogenase.

    Science.gov (United States)

    Dhar, T G Murali; Liu, Chunjian; Pitts, William J; Guo, Junquing; Watterson, Scott H; Gu, Henry; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Barrish, Joel C; Hollenbaugh, Diane; Iwanowicz, Edwin J

    2002-11-04

    A series of heterocyclic replacements for the central diamide moiety of 1, a potent small molecule inhibitor of inosine monophosphate dehydrogenase (IMPDH) were explored The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for these new series of inhibitors is given.

  2. Adenosine 5'-Monophosphate Aerosol Challenge Does Not Provoke Airflow Limitation in Healthy Cats

    Directory of Open Access Journals (Sweden)

    K. Vondráková

    2006-01-01

    Full Text Available The purpose of our study was to investigate the effects of nebulized adenosine 5'- monophosphate on airflow limitation in healthy cats determined by barometric whole body plethysmography (BWBP, in comparison to the effects of carbachol. Ten healthy 4- to 6-year-old domestic shorthair cats were included in the study. Each cat was placed in a BWBP plexiglass chamber (volume 38 l. Changes in box pressure were measured at baseline and after nebulization of vehicle and increasing concentrations of carbachol and adenosine 5'- monophosphate. Airway responsiveness was monitored as increases in enhanced pause (PENH, a unitless variable derived from dose-response curves estimating airflow limitation. The chosen endpoint was the agonist concentration which increased PENH to 300% of the value obtained after saline nebulization (PCPENH 300. Inter-day repeatability of measurements was assessed by repeated bronchoprovocations with both agonists 2-3 days apart. For carbachol, PCPENH300 was reached in all cats and correlated significantly between days (mean ± SD; 0.54 ± 0.42 mg/ml and 0.64 ± 0.45 mg/ml respectively; r = 0.58, p < 0.05 In contrast, we found no reaction to adenosine 5'- monophosphate even with the highest concentration nebulized during both measurements. At baseline, mean ± SD PENH was 0.47 ± 0.18 and 0.58 ± 0.24 (measurements 1 and 2, whereas PENH after 500 mg/ml adenosine 5'- monophosphate was 0.46 ± 0.20 and 0.71 ± 0.37. All bronchoprovocation tests were well tolerated by the cats. We conclude that healthy airways in cats do not demonstrate airway responsiveness to inhaled adenosine 5'- monophosphate. This is in agreement with observations in humans as well as our previous findings in dogs, where adenosine 5'- monophosphate had no effect on healthy canine airways, but caused significant airflow limitation after induction of acute bronchitis. To define the value of bronchoprovocation testing with adenosine 5'- monophosphate in the feline

  3. Molecular methods for the study of signal transduction in plants

    KAUST Repository

    Irving, Helen R.

    2013-09-03

    Novel and improved analytical methods have led to a rapid increase in our understanding of the molecular mechanism underlying plant signal transduction. Progress has been made both at the level of single-component analysis and in vivo imaging as well as at the systems level where transcriptomics and particularly phosphoproteomics afford a window into complex biological responses. Here we review the role of the cyclic nucleotides cAMP and cGMP in plant signal transduction as well as the discovery and biochemical and biological characterization of an increasing number of complex multi-domain nucleotide cyclases that catalyze the synthesis of cAMP and cGMP from ATP and GTP, respectively. © Springer Science+Business Media New York 2013.

  4. Protein and signaling networks in vertebrate photoreceptor cells

    Directory of Open Access Journals (Sweden)

    Karl-Wilhelm eKoch

    2015-11-01

    Full Text Available Vertebrate photoreceptor cells are exquisite light detectors operating under very dim and bright illumination. The photoexcitation and adaptation machinery in photoreceptor cells consists of protein complexes that can form highly ordered supramolecular structures and control the homeostasis and mutual dependence of the secondary messengers cGMP and Ca2+. The visual pigment in rod photoreceptors, the G protein-coupled receptor rhodopsin is organized in tracks of dimers thereby providing a signaling platform for the dynamic scaffolding of the G protein transducin. Illuminated rhodopsin is turned off by phosphorylation catalyzed by rhodopsin kinase GRK1 under control of Ca2+-recoverin. The GRK1 protein complex partly assembles in lipid raft structures, where shutting off rhodopsin seems to be more effective. Re-synthesis of cGMP is another crucial step in the recovery of the photoresponse after illumination. It is catalyzed by membrane bound sensory guanylate cyclases and is regulated by specific neuronal Ca2+-sensor proteins called GCAPs. At least one guanylate cyclase (ROS-GC1 was shown to be part of a multiprotein complex having strong interactions with the cytoskeleton and being controlled in a multimodal Ca2+-dependent fashion. The final target of the cGMP signaling cascade is a cyclic nucleotide-gated channel that is a hetero-oligomeric protein located in the plasma membrane and interacting with accessory proteins in highly organized microdomains. We summarize results and interpretations of findings related to the inhomogeneous organization of signaling units in photoreceptor outer segments.

  5. Cyclic adenosine monophosphate-dependent phosphorylation of mammalian mitochondrial proteins: enzyme and substrate characterization and functional role

    Czech Academy of Sciences Publication Activity Database

    Dobrová, Zuzana; Sardanelli, A. M.; Speranza, F.; Scacco, S.; Signorile, A.; Lorusso, V.; Papa, S.

    2001-01-01

    Roč. 40, - (2001), s. 13941-13947 ISSN 0006-2960 Institutional research plan: CEZ:AV0Z5020903 Keywords : cAMP * cyclic adenosine monophosphate Subject RIV: CE - Biochemistry Impact factor: 4.114, year: 2001

  6. Nitric Oxide Binds to and Modulates the Activity of a Pollen Specific Arabidopsis Diacylglycerol Kinase

    KAUST Repository

    Wong, Aloysius Tze

    2014-01-01

    Nitric oxide (NO) is an important signaling molecule in plants. In the pollen of Arabidopsis thaliana, NO causes re-orientation of the growing tube and this response is mediated by 3′,5′-cyclic guanosine monophosphate (cGMP). However, in plants, NO

  7. The NO/cGMP pathway inhibits transient cAMP signals through the activation of PDE2 in striatal neurons

    Directory of Open Access Journals (Sweden)

    Marina ePolito

    2013-11-01

    Full Text Available The NO-cGMP signaling plays an important role in the regulation of striatal function although the mechanisms of action of cGMP specifically in medium spiny neurons (MSNs remain unclear. Using genetically encoded fluorescent biosensors, including a novel Epac-based sensor (EPAC-SH150 with increased sensitivity for cAMP, we analyze the cGMP response to NO and whether it affected cAMP/PKA signaling in MSNs. The Cygnet2 sensor for cGMP reported large responses to NO donors in both striatonigral and striatopallidal MSNs, and this cGMP signal was controlled partially by PDE2. At the level of cAMP brief forskolin stimulations produced transient cAMP signals which differed between D1 and D2 medium spiny neurons. NO inhibited these cAMP transients through cGMP-dependent PDE2 activation, an effect that was translated and magnified downstream of cAMP, at the level of PKA. PDE2 thus appears as a critical effector of NO which modulates the post-synaptic response of MSNs to dopaminergic transmission.

  8. PPARα autocrine regulation of Ca²⁺-regulated exocytosis in guinea pig antral mucous cells: NO and cGMP accumulation.

    Science.gov (United States)

    Tanaka, Saori; Sugiyama, Nanae; Takahashi, Yuko; Mantoku, Daiki; Sawabe, Yukinori; Kuwabara, Hiroko; Nakano, Takashi; Shimamoto, Chikao; Matsumura, Hitoshi; Marunaka, Yoshinori; Nakahari, Takashi

    2014-12-15

    In antral mucous cells, acetylcholine (ACh, 1 μM) activates Ca(2+)-regulated exocytosis, consisting of a peak in exocytotic events that declines rapidly (initial phase) followed by a second slower decline (late phase) lasting during ACh stimulation. GW7647 [a peroxisome proliferation activation receptor α (PPARα) agonist] enhanced the ACh-stimulated initial phase, and GW6471 (a PPARα antagonist) abolished the GW7647-induced enhancement. However, GW6471 produced the delayed, but transient, increase in the ACh-stimulated late phase, and it also decreased the initial phase and produced the delayed increase in the late phase during stimulation with ACh alone. A similar delayed increase in the ACh-stimulated late phase is induced by an inhibitor of the PKG, Rp8BrPETcGMPS, suggesting that GW6471 inhibits cGMP accumulation. An inhibitor of nitric oxide synthase 1 (NOS1), N(5)-[imino(propylamino)methyl]-L-ornithine hydrochloride (N-PLA), also abolished the GW7647-induced-enhancement of ACh-stimulated initial phase but produced the delayed increase in the late phase. However, in the presence of N-PLA, an NO donor or 8BrcGMP enhanced the ACh-stimulated initial phase and abolished the delayed increase in the late phase. Moreover, GW7647 and ACh stimulated NO production and cGMP accumulation in antral mucosae, which was inhibited by GW6471 or N-PLA. Western blotting and immunohistochemistry revealed that NOS1 and PPARα colocalize in antral mucous cells. In conclusion, during ACh stimulation, a PPARα autocrine mechanism, which accumulates NO via NOS1 leading to cGMP accumulation, modulates the Ca(2+)-regulated exocytosis in antral mucous cells. Copyright © 2014 the American Physiological Society.

  9. Technological progress and challenges towards cGMP manufacturing of human pluripotent stem cells based therapeutic products for allogeneic and autologous cell therapies.

    Science.gov (United States)

    Abbasalizadeh, Saeed; Baharvand, Hossein

    2013-12-01

    Recent technological advances in the generation, characterization, and bioprocessing of human pluripotent stem cells (hPSCs) have created new hope for their use as a source for production of cell-based therapeutic products. To date, a few clinical trials that have used therapeutic cells derived from hESCs have been approved by the Food and Drug Administration (FDA), but numerous new hPSC-based cell therapy products are under various stages of development in cell therapy-specialized companies and their future market is estimated to be very promising. However, the multitude of critical challenges regarding different aspects of hPSC-based therapeutic product manufacturing and their therapies have made progress for the introduction of new products and clinical applications very slow. These challenges include scientific, technological, clinical, policy, and financial aspects. The technological aspects of manufacturing hPSC-based therapeutic products for allogeneic and autologous cell therapies according to good manufacturing practice (cGMP) quality requirements is one of the most important challenging and emerging topics in the development of new hPSCs for clinical use. In this review, we describe main critical challenges and highlight a series of technological advances in all aspects of hPSC-based therapeutic product manufacturing including clinical grade cell line development, large-scale banking, upstream processing, downstream processing, and quality assessment of final cell therapeutic products that have brought hPSCs closer to clinical application and commercial cGMP manufacturing. © 2013.

  10. Structural Characterization of the Molecular Events during a Slow Substrate-Product Transition in Orotidine 5'-Monophosphate Decarboxylase

    Energy Technology Data Exchange (ETDEWEB)

    Fujihashi, Masahiro; Wei, Lianhu; Kotra, Lakshmi P; Pai, Emil F; (TGRI); (Toronto); (Kyoto)

    2009-04-06

    Crystal structures of substrate-product complexes of Methanobacterium thermoautotrophicum orotidine 5'-monophosphate decarboxylase, obtained at various steps in its catalysis of the unusual transformation of 6-cyano-uridine 5'-monophosphate (UMP) into barbituric acid ribosyl monophosphate, show that the cyano substituent of the substrate, when bound to the active site, is first bent significantly from the plane of the pyrimidine ring and then replaced by an oxygen atom. Although the K72A and D70A/K72A mutants are either catalytically impaired or even completely inactive, they still display bending of the C6 substituent. Interestingly, high-resolution structures of the D70A and D75N mutants revealed a covalent bond between C6 of UMP and the Lys72 side chain after the -CN moiety's release. The same covalent bond was observed when the native enzyme was incubated with 6-azido-UMP and 6-iodo-UMP; in contrast, the K72A mutant transformed 6-iodo-UMP to barbituric acid ribosyl 5'-monophosphate. These results demonstrate that, given a suitable environment, native orotidine 5'-monophosphate decarboxylase and several of its mutants are not restricted to the physiologically relevant decarboxylation; they are able to catalyze even nucleophilic substitution reactions but consistently maintain distortion on the C6 substituent as an important feature of catalysis.

  11. Investigations of structural, dielectric and optical properties on silicon ion irradiated glycine monophosphate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kanagasekaran, T. [Department of Physics, Anna University, Chennai 600 025 (India); Department of Physics and Astrophysics, University of Delhi, New Delhi 110 007 (India); Mythili, P. [Department of Physics, Anna University, Chennai 600 025 (India); Bhagavannarayana, G. [Materials Characterization Division, National Physical Laboratory, New Delhi 110012 (India); Kanjilal, D. [Inter University Accelerator Centre, New Delhi 110 067 (India); Gopalakrishnan, R. [Department of Physics, Anna University, Chennai 600 025 (India)], E-mail: krgkrishnan@annauniv.edu

    2009-08-01

    The 50 MeV silicon ion irradiation induced modifications on structural, optical and dielectric properties of solution grown glycine monophosphate (GMP) crystals were studied. The high-resolution X-ray diffraction study shows the unaltered value of integrated intensity on irradiation. The dielectric constant as a function of frequency and temperature was studied. UV-visible studies reveal the decrease in bandgap values on irradiation and presence of F-centers. The fluorescence spectrum shows the existence of some energy levels, which remains unaffected after irradiation. The scanning electron micrographs reveal the defects formed on irradiation.

  12. Nitric oxide-induced signalling in rat lacrimal acinar cells

    DEFF Research Database (Denmark)

    Looms, Dagnia Karen; Tritsaris, K.; Dissing, S.

    2002-01-01

    -adrenergic stimulation and not by a rise in [Ca2+]i alone.   We show that in rat lacrimal acinar cells, NO and cGMP induce Ca2+ release from intracellular stores via G kinase activation. However, the changes in [Ca2+]i are relatively small, suggesting that this pathway plays a modulatory role in Ca2+ signalling, thus...... not by itself causing fast transient increases in [Ca2+]i. In addition, we suggest that endogenously produced NO activated by ß-adrenergic receptor stimulation, plays an important role in signalling to the surrounding tissue....

  13. Method of preparing thymidine-5'-monophosphate specifically or nonspecifically labelled with 14C or with 3H

    International Nuclear Information System (INIS)

    Nejedly, Z.; Filip, J.; Ekl, J.; Kolina, J.; Votruba, I.; Skoda, J.

    1977-01-01

    The invention claims a method for labelled thymidine-5'-monophosphate preparation by cultivating a special thymine-dependent Escherichia coli SPT - strain in the optimum synthetic culture medium containing 0.8 to 1.2 g/ml of labelled thymine. Practically the whole amount of labelled thymine is utilized for cellular deoxyribonucleic acid synthesis. The radioactive biomass obtained is processed using such chemical and enzymatic decomposition procedures as to allow separating the labelled thymidine-5'-monophosphate as the only thymine reaction product. Experiments conducted showed that the radiochemical purity of the thymidine-5'-monophosphate obtained was better than 98%. The absence of other nonactive substances was confirmed by spectrophotometric analysis. The overall product activity was 92.3% of the activity of thymine-2- 14 C introduced in the reaction. (Ha)

  14. Direct Determination of Six Cytokinin Nucleotide Monophosphates in Coconut Flesh by Reversed-Phase Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Cao, Zhao-Yun; Ma, You-Ning; Sun, Li-Hua; Mou, Ren-Xiang; Zhu, Zhi-Wei; Chen, Ming-Xue

    2017-11-15

    Coconut contains many uncharacterized cytokinins that have important physiological effects in plants and humans. In this work, a method based on liquid chromatography-tandem mass spectrometry was developed for identification and quantification of six cytokinin nucleotide monophosphates in coconut flesh. Excellent separation was achieved using a low-coverage C18 bonded-phase column with an acidic mobile phase, which greatly improved the retention of target compounds. To enable high-throughput analysis, a single-step solid-phase extraction using mixed-mode anion-exchange cartridges was employed for sample preparation. This proved to be an effective method to minimize matrix effects and ensure high selectivity. The limits of detection varied from 0.06 to 0.3 ng/mL, and the limits of quantification ranged from 0.2 to 1.0 ng/mL. The linearity was statistically verified over 2 orders of magnitude, giving a coefficient of determination (R 2 ) greater than 0.9981. The mean recoveries were from 81 to 108%; the intraday precision (n = 6) was less than 11%; and the interday precision (n = 11) was within 14%. The developed method was applied to the determination of cytokinin nucleotide monophosphates in coconut flesh samples, and four of them were successfully identified and quantified. The results showed that trans-zeatin riboside-5'-monophosphate was the dominant cytokinin, with a concentration of 2.7-34.2 ng/g, followed by N 6 -isopentenyladenosine-5'-monophosphate (≤12.9 ng/g), while the concentrations of cis-zeatin riboside-5'-monophosphate and dihydrozeatin riboside-5'-monophosphate were less than 2.2 and 4.9 ng/g, respectively.

  15. Kinetics of hydrogen-deuterium exchange in adenosine 5'-monophosphate, adenosine 3':5'-monophosphate, and poly(riboadenylic acid) determined by laser-Raman spectroscopy.

    Science.gov (United States)

    Thomas, G J; Livramento, J

    1975-11-18

    Pseudo-first-order rate constants governing the deuterium exchange of 8-CH groups in adenosine 5'-monophosphate, adenosine 3':5'-monophosphate, and poly(riboadenylic acid) (poly(rA)) were determined as a function of temperature in the range 20-90 degrees C by means of laser-Raman spectroscopy. For 5'-rAMP, the logarithm of the rate constant exhibits a strictly linear dependence on reciprocal temperature, i.e., kpsi = Ae-Ea/RT, with A = 2.3 X 10(14) hr-1 and Ea = 24.2 +/- 0.6 kcal/mol. For cAMP, above 50 degrees C, kpsi is nearly identical in magnitude and temperature dependence to that of 5'-rAMP. However, below 50 degrees C, isotope exchange in cAMP is much more rapid than in 5'-rAMP, characterized by a lower activation energy (17.7 kcal/mol) and frequency factor (9.6 X 10(9) hr-1). Exchange in poly(rA) is considerably slower than in 5'-rAMP at all temperatures, but like cAMP the in k vs. 1/T plot may be divided into high temperature and low temperature domains, each characterized by different Arrhenius parameters. Above 60 degrees C, poly(rA) gives Ea = 22.0 kcal/mol and A = 3.2 X 10(12) hr-1, while below 60 degrees C, Ea = 27.7 kcal/mol and A = 1.8 X 10(16) hr-1. Thus, increasing the temperature above 60 degrees C does not diminish the retardation of exchange in poly(rA) vis a vis 5'-rAMP. These results indicate that the distribution of electrons in the adenine ring of cAMP is altered by lowering the temperature below 50 degrees C, although no similar perturbation occurs for 5'-rAMP. Retardation of exchange in poly(rA) is most probably due to base stacking at lower temperatures and to steric hindrance from the ribopolymer backbone at higher temperatures. We also report the spectral effects of deuterium exchange on the vibrational Raman frequencies of 5'-rAMP, cAMP, and poly(rA) and suggest a number of new assignments for the 5' and cyclic ribosyl phosphate groups.

  16. Therapeutic effects of the joint administration of magnesium aspartate and adenosine monophosphate in gamma-irradiated mice

    International Nuclear Information System (INIS)

    Pospisil, M.; Netikova, J.; Pipalova, I.; Kozubik, A.

    1990-01-01

    The joint administration of magnesium aspartate and adenosine monophosphate, injected on days 1 to 4 post radiation, has been found to exert stimulatory effects on the recovery of hemopoietic functions in sublethally gamma-irradiated mice. These therapeutical effects were enhanced in animals protected by peroral administration of cystamine. The treatment scheme used did not modify survival of lethally irradiated mice. The therapeutic effects of magnesium aspartate and adenosine monophosphate in sublethally irradiated mice are explained by the stimulatory action of these drugs on the cell adenylate cyclase system, which influences the erythropoietic functions. (author)

  17. Protective effect of oral terfenadine and not inhaled ipratropium on adenosine 5 '-monophosphate-induced bronchoconstriction in patients with COPD

    NARCIS (Netherlands)

    Rutgers, [No Value; Koeter, GH; Van der Mark, TW; Postma, DS

    Background Inhalation of adenosine 5'-monophosphate (AMP) causes bronchoconstriction in patients with asthma and in many patients with chronic obstructive pulmonary disease (COPD). In asthma, AMP-induced bronchoconstriction has been shown to be determined mainly by release of mast cell mediators,

  18. The solvent effect on the enthalpy of hydrolysis of cyclic adenosine 3',5'-monophosphate : a quantum chemical study

    NARCIS (Netherlands)

    Scheffers - Sap, Miek; Buck, H.M.

    1978-01-01

    The solvent effect on the enthalpy of hydrolysis has been studied by the Extended-Hückel method for the hydrolysis reactions of cyclic adenosine 3',5'-monophosphate (cyclic 3',5'-AMP) and related cyclic phosphate diesters. The results show that the difference in enthalpy of hydrolysis between cyclic

  19. Inhibitors of inosine monophosphate dehydrogenase: SARs about the N-[3-Methoxy-4-(5-oxazolyl)phenyl moiety.

    Science.gov (United States)

    Iwanowicz, Edwin J; Watterson, Scott H; Guo, Junqing; Pitts, William J; Murali Dhar, T G; Shen, Zhongqi; Chen, Ping; Gu, Henry H; Fleener, Catherine A; Rouleau, Katherine A; Cheney, Daniel L; Townsend, Robert M; Hollenbaugh, Diane L

    2003-06-16

    The first reported structure-activity relationships (SARs) about the N-[3-methoxy-4-(5-oxazolyl)phenyl moiety for a series of recently disclosed inosine monophosphate dehydrogenase (IMPDH) inhibitors are described. The syntheses and in vitro inhibitory values for IMPDH II, and T-cell proliferation (for select analogues) are given.

  20. Hydrogels Based on Ag+ -Modulated Assembly of 5'-Adenosine Monophosphate for Enriching Biomolecules.

    Science.gov (United States)

    Hu, Yuanyuan; Xie, Dong; Wu, Yang; Lin, Nangui; Song, Aixin; Hao, Jingcheng

    2017-11-07

    Supramolecular hydrogels obtained by combining 5'-adenosine monophosphate (AMP) with Ag + were fabricated in this work. Their gelation capability was enhanced by increasing the concentration of Ag + or decreasing the pH. The gels are very sensitive to light, which endows them with potential applications as visible-light photosensitive materials. Coordination between the nucleobase of AMP and Ag + , as well as π-π stacking of nucleobases, are considered to be the main driving forces for self-assembly. The hydrogels successfully achieved the encapsulation and enrichment of biomolecules. Hydrogen bonding between the amino group of guest molecules and silver nanoparticles along the nanofibers drives the enrichment and is considered to be a crucial interaction. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Erythrocytic Adenosine Monophosphate as an Alternative Purine Source in Plasmodium falciparum*

    Science.gov (United States)

    Cassera, María B.; Hazleton, Keith Z.; Riegelhaupt, Paul M.; Merino, Emilio F.; Luo, Minkui; Akabas, Myles H.; Schramm, Vern L.

    2008-01-01

    Plasmodium falciparum is a purine auxotroph, salvaging purines from erythrocytes for synthesis of RNA and DNA. Hypoxanthine is the key precursor for purine metabolism in Plasmodium. Inhibition of hypoxanthine-forming reactions in both erythrocytes and parasites is lethal to cultured P. falciparum. We observed that high concentrations of adenosine can rescue cultured parasites from purine nucleoside phosphorylase and adenosine deaminase blockade but not when erythrocyte adenosine kinase is also inhibited. P. falciparum lacks adenosine kinase but can salvage AMP synthesized in the erythrocyte cytoplasm to provide purines when both human and Plasmodium purine nucleoside phosphorylases and adenosine deaminases are inhibited. Transport studies in Xenopus laevis oocytes expressing the P. falciparum nucleoside transporter PfNT1 established that this transporter does not transport AMP. These metabolic patterns establish the existence of a novel nucleoside monophosphate transport pathway in P. falciparum. PMID:18799466

  2. DNA-specific labelling by deoxyribonucleoside 5'-monophosphates in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Brendel, M.; Faeth, W.W.; Toper, R.

    1975-01-01

    Growth of 5'-dTMP low-requiring strains is inhibited by exogenous 5'-dGMP and 5'-GMP at concentrations higher than 5 x 10 -4 M. Synthesis of nucleic acids ceases and cells remain fixed in their respective place in the cell cycle. At concentrations lower than 10 -5 M deoxyribonucleoside 5'-monophosphates may be employed for radioactive labelling, the label being preferentially used for DNA synthesis. Affinity to DNA of the 5'-dNMPs is in the order of 5'-dAMPS > 5'-dGMP > 5'-dCMP > 5'-dUMP. DNA-specific label is achieved with 5'-dAMP when the medium is supplemented with adenine and deoxyadenosine. (orig.) [de

  3. Diphtheria toxin can simultaneously bind to its receptor and adenylyl-(3',5')-uridine 3'-monophosphate

    International Nuclear Information System (INIS)

    Barbieri, J.T.; Collins, C.M.; Collier, R.J.

    1986-01-01

    Diphtheria toxin (DT) that was bound to receptors on BS-C-1 cells was able to bind approximately 1 molar equiv of adenylyl-(3',5')-uridine 3'-monophosphate (ApUp). In contrast, receptor-bound CRM197, a mutant form of toxin with greatly diminished affinity for dinucleotides, did not bind ApUp. Affinity of the dinucleotide for receptor-bound toxin differed from that for free toxin by less than an order of magnitude. These results indicate that the receptor site and the ApUp site on the toxin do not significantly overlap. BS-C-1 cells were incubated with or without 125 I-DT or CRM 197. They were then incubated with [ 32 P]ApUp, and assayed

  4. Enhancement of radioprotective effectiveness of adenosine monophosphate by magnesium aspartate in mice

    International Nuclear Information System (INIS)

    Pospisil, M.; Netikova, J.; Kozubik, A.; Chertkov, K.S.; Ministry of Health, Moscow

    1988-01-01

    The enhancing effect of magnesium aspartate on the radioprotective effectiveness of adenosine monophosphate (AMP) administered to whole-body gamma-irradiated mice was studied. Male (CBA x C57BL/10)F 1 hybrid mice of a mean body weight of 32 g were used. 5 mg AMP per mouse was injected i.p. 15 min before and 15 min after irradiation; magnesium aspartate (13.3 mg per mouse) was administered s.c. 35 min before irradiation. The benefical effect of the drug combination used was manifested when investigating hematological indices at the recovery phase of sublethally irradiated animals, as well as when observing the survival of lethally irradiated mice. The synergistic radioprotective effects of AMP and magnesium aspartate are explained by the stimulatory action of both these compounds on the cell adenylate cyclase system. (author)

  5. Inhibition of Cyclic Adenosine Monophosphate-Specific Phosphodiesterase by Various Food Plant-Derived Phytotherapeutic Agents.

    Science.gov (United States)

    Röhrig, Teresa; Pacjuk, Olga; Hernández-Huguet, Silvia; Körner, Johanna; Scherer, Katharina; Richling, Elke

    2017-11-04

    Background: Phosphodiesterases (PDEs) play a major role in the regulation of cyclic adenosine monophosphate (cAMP)- and cyclic guanosine monophosphate (cGMP)-mediated pathways. Their inhibitors exhibit anti-inflammatory, vasodilatory and antithrombotic effects. Therefore, consumption of foods with PDE-inhibiting potential may possess beneficial influence on the risk of cardiovascular diseases. Methods: Four plant extracts ( Arbutus unedo , Camellia sinensis , Cynara scolymus , Zingiber officinale ) with promising ingredient profiles and physiological effects were tested for their ability to inhibit cAMP-specific PDE in vitro in a radioactive assay. Results: Strawberry tree fruit ( Arbutus unedo ) and tea ( Camellia sinensis ) extracts did not inhibit PDE markedly. Alternatively, artichoke ( Cynara scolymus ) extract had a significant inhibitory influence on PDE activity (IC 50 = 0.9 ± 0.1 mg/mL) as well as its flavone luteolin (IC 50 = 41 ± 10 μM) and 3,4-dicaffeoylquinic acid (IC 50 > 1.0 mM). Additionally, the ginger ( Zingiber officinale ) extract and one of its constituents, [6]-gingerol, significantly inhibited PDE (IC 50 = 1.7 ± 0.2 mg/mL and IC 50 > 1.7 mM, respectively). Crude fractionation of ginger extract showed that substances responsible for PDE inhibition were in the lipoid fraction (IC 50 = 455 ± 19 μg/mL). Conclusions: A PDE-inhibitory effect was shown for artichoke and ginger extract. Whether PDE inhibition in vivo can be achieved through ingestion of artichoke or ginger extracts leading to physiological effects concerning cardiovascular health should be addressed in future research.

  6. Inhibition of Cyclic Adenosine Monophosphate-Specific Phosphodiesterase by Various Food Plant-Derived Phytotherapeutic Agents

    Directory of Open Access Journals (Sweden)

    Teresa Röhrig

    2017-11-01

    Full Text Available Background: Phosphodiesterases (PDEs play a major role in the regulation of cyclic adenosine monophosphate (cAMP- and cyclic guanosine monophosphate (cGMP-mediated pathways. Their inhibitors exhibit anti-inflammatory, vasodilatory and antithrombotic effects. Therefore, consumption of foods with PDE-inhibiting potential may possess beneficial influence on the risk of cardiovascular diseases. Methods: Four plant extracts (Arbutus unedo, Camellia sinensis, Cynara scolymus, Zingiber officinale with promising ingredient profiles and physiological effects were tested for their ability to inhibit cAMP-specific PDE in vitro in a radioactive assay. Results: Strawberry tree fruit (Arbutus unedo and tea (Camellia sinensis extracts did not inhibit PDE markedly. Alternatively, artichoke (Cynara scolymus extract had a significant inhibitory influence on PDE activity (IC50 = 0.9 ± 0.1 mg/mL as well as its flavone luteolin (IC50 = 41 ± 10 μM and 3,4-dicaffeoylquinic acid (IC50 > 1.0 mM. Additionally, the ginger (Zingiber officinale extract and one of its constituents, [6]-gingerol, significantly inhibited PDE (IC50 = 1.7 ± 0.2 mg/mL and IC50 > 1.7 mM, respectively. Crude fractionation of ginger extract showed that substances responsible for PDE inhibition were in the lipoid fraction (IC50 = 455 ± 19 μg/mL. Conclusions: A PDE-inhibitory effect was shown for artichoke and ginger extract. Whether PDE inhibition in vivo can be achieved through ingestion of artichoke or ginger extracts leading to physiological effects concerning cardiovascular health should be addressed in future research.

  7. Effect of the cGMP pathway on AQP2 expression and translocation: potential implications for nephrogenic diabetes insipidus.

    NARCIS (Netherlands)

    Boone, M.; Kortenoeven, M.L.A.; Robben, J.H.; Deen, P.M.T.

    2010-01-01

    BACKGROUND: Arginine vasopressin (AVP) binding to the V2 receptor (V2R) in renal collecting duct principal cells induces a cAMP signalling cascade resulting in the activation of protein kinase A (PKA), translocation of aquaporin-2 (AQP2) to the apical membrane and an increase in AQP2 expression.

  8. The influence of Na+,K+-ATPase on glutamate signaling in neurodegenerative diseases and senescence

    Directory of Open Access Journals (Sweden)

    Paula Fernanda Kinoshita

    2016-06-01

    Full Text Available Decreased Na+,K+-ATPase (NKA activity causes energy deficiency, which is commonly observed in neurodegenerative diseases. The NKA is constituted of three subunits: α, β and γ, with four distinct isoforms of the catalytic α subunit (α1-4. Genetic mutations in the ATP1A2 gene and ATP1A3 gene, encoding the α2 and α3 subunit isoforms, respectively can cause distinct neurological disorders, concurrent to impaired NKA activity. Within the central nervous system (CNS, the α2 isoform is expressed mostly in glial cells and the α3 isoform is neuron-specific. Mutations in ATP1A2 gene can result in familial hemiplegic migraine (FHM2, while mutations in the ATP1A3 gene can cause Rapid-onset dystonia-Parkinsonism (RDP and alternating hemiplegia of childhood (AHC, as well as the cerebellar ataxia, areflexia, pescavus, optic atrophy and sensorineural hearing loss (CAPOS syndrome. Data indicates that the central glutamatergic system is affected by mutations in the α2 isoform, however further investigations are required to establish a connection to mutations in the α3 isoform, especially given the diagnostic confusion and overlap with glutamate transporter disease. The age-related decline in brain α2/3 activity may arise from changes in the cyclic guanosine monophosphate (cGMP and cGMP‐dependent protein kinase (PKG pathway. Glutamate, through nitric oxide synthase (NOS, cGMP and PKG, stimulates brain α2/3 activity, with the glutamatergic N-methyl-D-aspartate (NMDA receptor cascade able to drive an adaptive, neuroprotective response to inflammatory and challenging stimuli, including amyloid‐β. Here we review the NKA, both as an ion pump as well as a receptor that interacts with NMDA, including the role of NKA subunits mutations. Failure of the NKA-associated adaptive response mechanisms may render neurons more susceptible to degeneration over the course of aging.

  9. The Gyc76C Receptor Guanylyl Cyclase and the Foraging cGMP-Dependent Kinase Regulate Extracellular Matrix Organization and BMP Signaling in the Developing Wing of Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Justin Schleede

    2015-10-01

    Full Text Available The developing crossveins of the wing of Drosophila melanogaster are specified by long-range BMP signaling and are especially sensitive to loss of extracellular modulators of BMP signaling such as the Chordin homolog Short gastrulation (Sog. However, the role of the extracellular matrix in BMP signaling and Sog activity in the crossveins has been poorly explored. Using a genetic mosaic screen for mutations that disrupt BMP signaling and posterior crossvein development, we identify Gyc76C, a member of the receptor guanylyl cyclase family that includes mammalian natriuretic peptide receptors. We show that Gyc76C and the soluble cGMP-dependent kinase Foraging, likely linked by cGMP, are necessary for normal refinement and maintenance of long-range BMP signaling in the posterior crossvein. This does not occur through cell-autonomous crosstalk between cGMP and BMP signal transduction, but likely through altered extracellular activity of Sog. We identify a novel pathway leading from Gyc76C to the organization of the wing extracellular matrix by matrix metalloproteinases, and show that both the extracellular matrix and BMP signaling effects are largely mediated by changes in the activity of matrix metalloproteinases. We discuss parallels and differences between this pathway and other examples of cGMP activity in both Drosophila melanogaster and mammalian cells and tissues.

  10. The Gyc76C Receptor Guanylyl Cyclase and the Foraging cGMP-Dependent Kinase Regulate Extracellular Matrix Organization and BMP Signaling in the Developing Wing of Drosophila melanogaster.

    Science.gov (United States)

    Schleede, Justin; Blair, Seth S

    2015-10-01

    The developing crossveins of the wing of Drosophila melanogaster are specified by long-range BMP signaling and are especially sensitive to loss of extracellular modulators of BMP signaling such as the Chordin homolog Short gastrulation (Sog). However, the role of the extracellular matrix in BMP signaling and Sog activity in the crossveins has been poorly explored. Using a genetic mosaic screen for mutations that disrupt BMP signaling and posterior crossvein development, we identify Gyc76C, a member of the receptor guanylyl cyclase family that includes mammalian natriuretic peptide receptors. We show that Gyc76C and the soluble cGMP-dependent kinase Foraging, likely linked by cGMP, are necessary for normal refinement and maintenance of long-range BMP signaling in the posterior crossvein. This does not occur through cell-autonomous crosstalk between cGMP and BMP signal transduction, but likely through altered extracellular activity of Sog. We identify a novel pathway leading from Gyc76C to the organization of the wing extracellular matrix by matrix metalloproteinases, and show that both the extracellular matrix and BMP signaling effects are largely mediated by changes in the activity of matrix metalloproteinases. We discuss parallels and differences between this pathway and other examples of cGMP activity in both Drosophila melanogaster and mammalian cells and tissues.

  11. Cyclic guanosine monophosphate does not inhibit gonadotropin-induced activation of mitogen-activated protein kinase 3/1 in pig cumulus-oocyte complexes

    Czech Academy of Sciences Publication Activity Database

    Blaha, Milan; Němcová, Lucie; Procházka, Radek

    2015-01-01

    Roč. 13, č. 1 (2015) ISSN 1477-7827 R&D Projects: GA ČR GAP502/11/0593; GA MZe QI101A166 Institutional support: RVO:67985904 Keywords : pig * oocyte * cGMP Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.147, year: 2015

  12. cGMP may have trophic effects on beta cell function comparable to those of cAMP, implying a role for high-dose biotin in prevention/treatment of diabetes.

    Science.gov (United States)

    McCarty, Mark F

    2006-01-01

    Incretin hormones have trophic effects on beta cell function that can aid prevention and treatment of diabetes. cAMP is the primary mediator of these effects, and has been shown to potentiate glucose-stimulated insulin secretion, promote proper beta cells differentiation by increasing expression of the crucial transcription factor PDX-1, and prevent beta cell apoptosis. cGMP's role in beta cell function has received far less scrutiny, but there is emerging evidence that it may have a trophic impact on beta cell function analogous to that of cAMP. An increase in plasma glucose boosts beta cell production of cGMP, which acts as a feed-forward mediator to enhance glucose-stimulated insulin secretion. cGMP also has an anti-apoptotic effect in beta cells, and there is now indirect evidence that it promotes expression of PDX-1. Supraphysiological concentrations of biotin can directly activate guanylate cyclase, and there is limited evidence that high intakes of this vitamin can be therapeutically beneficial in diabetics and in rodent models of diabetes. Beneficial effects of cGMP on muscle insulin sensitivity and on control of hepatic glucose output may contribute to biotin's utility in diabetes. The fact that nitric oxide/cGMP exert a range of favorable effects on vascular health should further encourage exploration of biotin's preventive and therapeutic potential. If an appropriate high-dose biotin regimen could achieve a modest systemic increase in guanylate cyclase activity, without entailing unacceptable side effects or risks, such a regimen might have considerable potential for promoting vascular health and preventing or managing diabetes.

  13. Crystallization and preliminary crystallographic analysis of orotidine 5′-monophosphate decarboxylase from the human malaria parasite Plasmodium falciparum

    International Nuclear Information System (INIS)

    Krungkrai, Sudaratana R.; Tokuoka, Keiji; Kusakari, Yukiko; Inoue, Tsuyoshi; Adachi, Hiroaki; Matsumura, Hiroyoshi; Takano, Kazufumi; Murakami, Satoshi; Mori, Yusuke; Kai, Yasushi; Krungkrai, Jerapan; Horii, Toshihiro

    2006-01-01

    Orotidine 5′-monophosphate decarboxylase of human malaria parasite P. falciparum was crystallized by the seeding method in a hanging drop using PEG 3000 as a precipitant. A complete set of diffraction data from a native crystal was collected to 2.7 Å resolution at 100 K using synchrotron radiation. Orotidine 5′-monophosphate (OMP) decarboxylase (OMPDC; EC 4.1.1.23) catalyzes the final step in the de novo synthesis of uridine 5′-monophosphate (UMP) and defects in the enzyme are lethal in the malaria parasite Plasmodium falciparum. Active recombinant P. falciparum OMPDC (PfOMPDC) was crystallized by the seeding method in a hanging drop using PEG 3000 as a precipitant. A complete set of diffraction data from a native crystal was collected to 2.7 Å resolution at 100 K using synchrotron radiation at the Swiss Light Source. The crystal exhibits trigonal symmetry (space group R3), with hexagonal unit-cell parameters a = b = 201.81, c = 44.03 Å. With a dimer in the asymmetric unit, the solvent content is 46% (V M = 2.3 Å 3 Da −1 )

  14. The type II cGMP dependent protein kinase regulates GluA1 levels at the plasma membrane of developing cerebellar granule cells

    Science.gov (United States)

    Incontro, Salvatore; Ciruela, Francisco; Ziff, Edward; Hofmann, Franz; Sánchez-Prieto, José; Torres, Magdalena

    2014-01-01

    Trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) is regulated by specific interactions with other proteins and by post-translational mechanisms, such as phosphorylation. We have found that the type II cGMP-dependent protein kinase (cGKII) phosphorylates GluA1 (formerly GluR1) at S845, augmenting the surface expression of AMPARs at both synaptic and extrasynaptic sites. Activation of cGKII by 8-Br-cGMP enhances the surface expression of GluA1, whereas its inhibition or suppression effectively diminished the expression of this protein at the cell surface. In granule cells, NMDA receptor activation (NMDAR) stimulates nitric oxide and cGMP production, which in turn activates cGKII and induces the phosphorylation of GluA1, promoting its accumulation in the plasma membrane. GluA1 is mainly incorporated into calcium permeable AMPARs as exposure to 8-Br-cGMP or NMDA activation enhanced AMPA-elicited calcium responses that are sensitive to NASPM inhibition. We summarize evidence for an increase of calcium permeable AMPA receptors downstream of NMDA receptor activation that might be relevant for granule cell development and plasticity. PMID:23545413

  15. Adenosine Monophosphate Binding Stabilizes the KTN Domain of the Shewanella denitrificans Kef Potassium Efflux System.

    Science.gov (United States)

    Pliotas, Christos; Grayer, Samuel C; Ekkerman, Silvia; Chan, Anthony K N; Healy, Jess; Marius, Phedra; Bartlett, Wendy; Khan, Amjad; Cortopassi, Wilian A; Chandler, Shane A; Rasmussen, Tim; Benesch, Justin L P; Paton, Robert S; Claridge, Timothy D W; Miller, Samantha; Booth, Ian R; Naismith, James H; Conway, Stuart J

    2017-08-15

    Ligand binding is one of the most fundamental properties of proteins. Ligand functions fall into three basic types: substrates, regulatory molecules, and cofactors essential to protein stability, reactivity, or enzyme-substrate complex formation. The regulation of potassium ion movement in bacteria is predominantly under the control of regulatory ligands that gate the relevant channels and transporters, which possess subunits or domains that contain Rossmann folds (RFs). Here we demonstrate that adenosine monophosphate (AMP) is bound to both RFs of the dimeric bacterial Kef potassium efflux system (Kef), where it plays a structural role. We conclude that AMP binds with high affinity, ensuring that the site is fully occupied at all times in the cell. Loss of the ability to bind AMP, we demonstrate, causes protein, and likely dimer, instability and consequent loss of function. Kef system function is regulated via the reversible binding of comparatively low-affinity glutathione-based ligands at the interface between the dimer subunits. We propose this interfacial binding site is itself stabilized, at least in part, by AMP binding.

  16. The clinical correlation of regulatory T cells and cyclic adenosine monophosphate in enterovirus 71 infection.

    Directory of Open Access Journals (Sweden)

    Shih-Min Wang

    Full Text Available Brainstem encephalitis (BE and pulmonary edema (PE are notable complications of enterovirus 71 (EV71 infection.This study investigated the immunoregulatory characterizations of EV71 neurological complications by disease severity and milrinone treatment.Patients <18 years with virologically confirmed EV71 infections were enrolled and divided into 2 groups: the hand, foot, and mouth disease (HFMD or BE group, and the autonomic nervous system (ANS dysregulation or PE group. Cytokine and cyclic adenosine monophosphate (cAMP levels, and the regulatory T cell (Tregs profiles of the patients were determined.Patients with ANS dysregulation or PE exhibited significantly low frequency of CD4(+CD25(+Foxp3+ and CD4(+Foxp3(+ T cells compared with patients with HFMD or BE. The expression frequency of CD4-CD8- was also significantly decreased in patients with ANS dysregulation or PE. Among patients with ANS dysregulation or PE, the expression frequency of CD4+Foxp3+ increased markedly after milrinone treatment, and was associated with reduction of plasma levels IL-6, IL-8 and IL-10. Plasma concentrations of cAMP were significantly decreased in patients with ANS dysregulation or PE compared with patients with HFMD or BE; however, cAMP levels increased after milrinone treatment.These findings suggested decreased different regulatory T populations and cAMP expression correlate with increased EV71 disease severity. Improved outcome after milrinone treatment may associate with increased regulatory T populations, cAMP expression and modulation of cytokines levels.

  17. Identification of the orotidine-5'-monophosphate decarboxylase gene of the oleaginous yeast Rhodosporidium toruloides.

    Science.gov (United States)

    Yang, Fan; Zhang, Sufang; Tang, Wei; Zhao, Zongbao K

    2008-09-01

    Oleaginous yeast Rhodosporidium toruloides is an excellent microbial lipid producer of great industrial potential, yet there is no effective genetic tool for rationally engineering this microorganism. To develop a marker recycling system, the orotidine-5'-monophosphate (OMP) decarboxylase gene of R. toruloides (RtURA3) was isolated using methods of degenerate polymerase chain reaction (PCR) together with rapid amplification of cDNA ends. The results showed that RtURA3 contains four extrons and three introns, and that the encoded polypeptide holds a sequence of 279 amino acid residues with significant homology to those of OMP decarboxylases from other yeasts. A shuttle vector pYES2/CT-RtURA3 was constructed via site-specific insertion of RtURA3 into the commercial vector pYES2/CT. Transformation of the shuttle vector into Saccharomyces cerevisiae BY4741, a URA3-deficient yeast strain, ensured the viability of the strain on synthetic dextrose agar plate without uracil, suggesting that the isolated RtURA3 was functionally equivalent to the URA3 gene from S. cerevisiae.

  18. Inosine-5'-monophosphate is a candidate agent to resolve rigor mortis of skeletal muscle.

    Science.gov (United States)

    Matsuishi, Masanori; Tsuji, Mariko; Yamaguchi, Megumi; Kitamura, Natsumi; Tanaka, Sachi; Nakamura, Yukinobu; Okitani, Akihiro

    2016-11-01

    The object of the present study was to reveal the action of inosine-5'-monophosphate (IMP) toward myofibrils in postmortem muscles. IMP solubilized isolated actomyosin within a narrow range of KCl concentration, 0.19-0.20 mol/L, because of the dissociation of actomyosin into actin and myosin, but it did not solubilize the proteins in myofibrils with 0.2 mol/L KCl. However, IMP could solubilize both proteins in myofibrils with 0.2 mol/L KCl in the presence of 1 m mol/L pyrophosphate or 1.0-3.3 m mol/L adenosine-5'-diphosphate (ADP). Thus, we presumed that pyrophosphate and ADP released thin filaments composed of actin, and thick filaments composed of myosin from restraints of myofibrils, and then both filaments were solubilized through the IMP-induced dissociation of actomyosin. Thus, we concluded that IMP is a candidate agent to resolve rigor mortis because of its ability to break the association between thick and thin filaments. © 2016 Japanese Society of Animal Science.

  19. A Mixed-Valent Molybdenum Monophosphate with a Layer Structure: KMo 3P 2O 14

    Science.gov (United States)

    Guesdon, A.; Borel, M. M.; Leclaire, A.; Grandin, A.; Raveau, B.

    1994-03-01

    A new mixed-valent molybdenum monophosphate with a layer structure KMo 3P 2O 14 has been isolated. It crystallizes in the space group P2 1/ m with a = 8.599(2) Å, b = 6.392(2) Å, c = 10.602(1) Å, and β = 111.65(2)°. The layers [Mo 3P 2O 14] ∞ are parallel to (100) and consist of [MoPO 8] ∞ chains running along limitb→ , in which one MoO 6 octahedron alternates with one PO 4 tetrahedron. In fact, four [MoPO 8] ∞ chains share the corners of their polyhedra and the edges of their octahedra, forming [Mo 4P 4O 24] ∞ columns which are linked through MoO 5 bipyramids along limitc→. The K + ions interleaved between these layers are surrounded by eight oxygens, forming bicapped trigonal prisms KO 8. Besides the unusual trigonal bipyramids MoO 5, this structure is also characterized by a tendency to the localization of the electrons, since one octahedral site is occupied by Mo(V), whereas the other octahedral site and the trigonal bipyramid are occupied by Mo(VI). The similarity of this structure with pure octahedral layer structures suggests the possibility of generating various derivatives, and of ion exchange properties.

  20. Controlled supramolecular structure of guanosine monophosphate in the interlayer space of layered double hydroxide

    Directory of Open Access Journals (Sweden)

    Gyeong-Hyeon Gwak

    2016-12-01

    Full Text Available Guanosine monophosphates (GMPs were intercalated into the interlayer space of layered double hydroxides (LDHs and the molecular arrangement of GMP was controlled in LDHs. The intercalation conditions such as GMP/LDH molar ratio and reaction temperature were systematically adjusted. When the GMP/LDH molar ratio was 1:2, which corresponds to the charge balance between positive LDH sheets and GMP anions, GMP molecules were well-intercalated to LDH. At high temperature (100 and 80 °C, a single GMP molecule existed separately in the LDH interlayer. On the other hand, at lower temperature (20, 40 and 60 °C, GMPs tended to form ribbon-type supramolecular assemblies. Differential scanning calorimetry showed that the ribbon-type GMP assembly had an intermolecular interaction energy of ≈101 kJ/mol, which corresponds to a double hydrogen bond between guanosine molecules. Once stabilized, the interlayer GMP orientations, single molecular and ribbon phase, were successfully converted to the other phase by adjusting the external environment by stoichiometry or temperature control.

  1. Uridine 5'-Monophosphate Synthase Is Transcriptionally Regulated by Pyrimidine Levels in Nicotiana plumbaginifolia

    Science.gov (United States)

    Santoso; Thornburg

    1998-02-01

    To understand the regulation and expression of pyrimidine biosynthesis in plants, we have examined the effect of the metabolic inhibitor 5-fluoroorotic acid (FOA) on uridine-5'-monophosphate synthase (UMPSase) expression in cell cultures of Nicotiana plumbaginifolia. UMPSase is the rate-limiting step of pyrimidine biosynthesis in plants. Addition of FOA causes an up-regulation of UMPSase enzyme activity in cell cultures after a lag phase of several days. Western-blot analysis demonstrated that the up-regulation in enzyme activity was caused by increased expression of the UMPSase protein. Northern-blot analysis demonstrated a higher level of UMPSase mRNA in the FOA-induced tissues than in control tissues. Run-on transcriptional assays showed that the UMPSase gene was transcriptionally activated after FOA treatment. The mechanism of toxicity of FOA is through thymine starvation. We found that addition of thymine abrogated the FOA-mediated up-regulation of UMPSase. In addition, methotrexate and aminopterin, which affect thymine levels by inhibiting dihydrofolate reductase, also up-regulate UMPSase in N. plumbaginifolia cells.

  2. Uridine 5′-Monophosphate Synthase Is Transcriptionally Regulated by Pyrimidine Levels in Nicotiana plumbaginifolia1

    Science.gov (United States)

    Santoso, Djoko; Thornburg, Robert

    1998-01-01

    To understand the regulation and expression of pyrimidine biosynthesis in plants, we have examined the effect of the metabolic inhibitor 5-fluoroorotic acid (FOA) on uridine-5′-monophosphate synthase (UMPSase) expression in cell cultures of Nicotiana plumbaginifolia. UMPSase is the rate-limiting step of pyrimidine biosynthesis in plants. Addition of FOA causes an up-regulation of UMPSase enzyme activity in cell cultures after a lag phase of several days. Western-blot analysis demonstrated that the up-regulation in enzyme activity was caused by increased expression of the UMPSase protein. Northern-blot analysis demonstrated a higher level of UMPSase mRNA in the FOA-induced tissues than in control tissues. Run-on transcriptional assays showed that the UMPSase gene was transcriptionally activated after FOA treatment. The mechanism of toxicity of FOA is through thymine starvation. We found that addition of thymine abrogated the FOA-mediated up-regulation of UMPSase. In addition, methotrexate and aminopterin, which affect thymine levels by inhibiting dihydrofolate reductase, also up-regulate UMPSase in N. plumbaginifolia cells. PMID:9490773

  3. Hit discovery of Mycobacterium tuberculosis inosine 5'-monophosphate dehydrogenase, GuaB2, inhibitors.

    Science.gov (United States)

    Sahu, Niteshkumar U; Singh, Vinayak; Ferraris, Davide M; Rizzi, Menico; Kharkar, Prashant S

    2018-04-18

    Tuberculosis remains a global concern. There is an urgent need of newer antitubercular drugs due to the development of resistant forms of Mycobacterium tuberculosis (Mtb). Inosine 5'-monophosphate dehydrogenase (IMPDH), guaB2, of Mtb, required for guanine nucleotide biosynthesis, is an attractive target for drug development. In this study, we screened a focused library of 73 drug-like molecules with desirable calculated/predicted physicochemical properties, for growth inhibitory activity against drug-sensitive MtbH37Rv. The eight hits and mycophenolic acid, a prototype IMPDH inhibitor, were further evaluated for activity on purified Mtb-GuaB2 enzyme, target selectivity using a conditional knockdown mutant of guaB2 in Mtb, followed by cross-resistance to IMPDH inhibitor-resistant SRMV2.6 strain of Mtb, and activity on human IMPDH2 isoform. One of the hits, 13, a 5-amidophthalide derivative, has shown growth inhibitory potential and target specificity against the Mtb-GuaB2 enzyme. The hit, 13, is a promising molecule with potential for further development as an antitubercular agent. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. G-Protein Gαs controls medulloblastoma initiation by suppressing sonic hedgehog signaling.

    Science.gov (United States)

    He, Xuelian; Lu, Q Richard

    2015-01-01

    We identify Gαs as a novel tumor suppressor in medulloblastoma that functions principally by inhibition of sonic hedgehog signaling. Gαs not only stimulates cyclic adenosine monophosphate (cAMP)-dependent signaling but also inhibits ciliary trafficking of hedgehog components. Elevation of cAMP inhibits medulloblastoma growth and augments inhibition of smoothened to decrease tumor cell proliferation, thus highlighting Gαs as a potential therapeutic target.

  5. A Facile and Sensitive Method for Quantification of Cyclic Nucleotide Monophosphates in Mammalian Organs: Basal Levels of Eight cNMPs and Identification of 2',3'-cIMP

    Directory of Open Access Journals (Sweden)

    Xin Jia

    2014-12-01

    Full Text Available A sensitive, versatile and economical method to extract and quantify cyclic nucleotide monophosphates (cNMPs using LC-MS/MS, including both 3',5'-cNMPs and 2',3'-cNMPs, in mammalian tissues and cellular systems has been developed. Problems, such as matrix effects from complex biological samples, are addressed and have been optimized. This protocol allows for comparison of multiple cNMPs in the same system and was used to examine the relationship between tissue levels of cNMPs in a panel of rat organs. In addition, the study reports the first identification and quantification of 2',3'-cIMP. The developed method will allow for quantification of cNMPs levels in cells and tissues with varying disease states, which will provide insight into the role(s and interplay of cNMP signalling pathways.

  6. A facile and sensitive method for quantification of cyclic nucleotide monophosphates in mammalian organs: basal levels of eight cNMPs and identification of 2',3'-cIMP.

    Science.gov (United States)

    Jia, Xin; Fontaine, Benjamin M; Strobel, Fred; Weinert, Emily E

    2014-12-12

    A sensitive, versatile and economical method to extract and quantify cyclic nucleotide monophosphates (cNMPs) using LC-MS/MS, including both 3',5'-cNMPs and 2',3'-cNMPs, in mammalian tissues and cellular systems has been developed. Problems, such as matrix effects from complex biological samples, are addressed and have been optimized. This protocol allows for comparison of multiple cNMPs in the same system and was used to examine the relationship between tissue levels of cNMPs in a panel of rat organs. In addition, the study reports the first identification and quantification of 2',3'-cIMP. The developed method will allow for quantification of cNMPs levels in cells and tissues with varying disease states, which will provide insight into the role(s) and interplay of cNMP signalling pathways.

  7. Cyclic di-adenosine monophosphate (c-di-AMP) is required for osmotic regulation in Staphylococcus aureus but dispensable for viability in anaerobic conditions.

    Science.gov (United States)

    Zeden, Merve S; Schuster, Christopher F; Bowman, Lisa; Zhong, Qiyun; Williams, Huw D; Gründling, Angelika

    2018-03-02

    Cyclic di-adenosine monophosphate (c-di-AMP) is a recently discovered signaling molecule important for the survival of Firmicutes, a large bacterial group that includes notable pathogens such as Staphylococcus aureus However, the exact role of this molecule has not been identified. dacA , the S. aureus gene encoding the diadenylate cyclase enzyme required for c-di-AMP production, cannot be deleted when bacterial cells are grown in rich medium, indicating that c-di-AMP is required for growth in this condition. Here, we report that an S. aureus dacA mutant can be generated in chemically defined medium. Consistent with previous findings, this mutant had a severe growth defect when cultured in rich medium. Using this growth defect in rich medium, we selected for suppressor strains with improved growth to identify c-di-AMP-requiring pathways. Mutations bypassing the essentiality of dacA were identified in alsT and opuD, encoding a predicted amino acid and osmolyte transporter, the latter of which we show here to be the main glycine betaine-uptake system in S. aureus. Inactivation of these transporters likely prevents the excessive osmolyte and amino acid accumulation in the cell, providing further evidence for a key role of c-di-AMP in osmotic regulation. Suppressor mutations were also obtained in hepS, hemB, ctaA, and qoxB, coding proteins required for respiration. Furthermore, we show that dacA is dispensable for growth in anaerobic conditions. Together, these findings reveal an essential role for the c-di-AMP signaling network in aerobic, but not anaerobic, respiration in S. aureus . © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Cows are not mice: the role of cyclic AMP, phosphodiesterases, and adenosine monophosphate-activated protein kinase in the maintenance of meiotic arrest in bovine oocytes.

    Science.gov (United States)

    Bilodeau-Goeseels, Sylvie

    2011-01-01

    Meiotic maturation in mammalian oocytes is initiated during fetal development, and is then arrested at the dictyate stage - possibly for several years. Oocyte meiosis resumes in preovulatory follicles in response to the lutenizing hormone (LH) surge or spontaneously when competent oocytes are removed from follicles and cultured. The mechanisms involved in meiotic arrest and resumption in bovine oocytes are not fully understood, and several studies point to important differences between oocytes from rodent and livestock species. This paper reviews earlier and contemporary studies on the effects of cAMP-elevating agents and phosphodiesterase (PDE) enzyme inhibitors on the maintenance of meiotic arrest in bovine oocytes in vitro. Contrary to results obtained with mouse oocytes, bovine oocyte meiosis is inhibited by activators of the energy sensor adenosine monophosphate-activated protein kinase (AMPK, mammalian gene PRKA), which is activated by AMP, the degradation product of cAMP. It is not clear whether or not the effects were due to AMPK activation, and they may depend on culture conditions. Evidence suggests that other signaling pathways (for example, the cGMP/nitric oxide pathway) are involved in bovine oocyte meiotic arrest, but further studies are needed to understand the interactions between the signaling pathways that lead to maturation promoting factor (MPF) being inactive or active. An improved understanding of the mechanisms involved in the control of bovine oocyte meiosis will facilitate better control of the process in vitro, resulting in increased developmental competence and increased efficiency of in vitro embryo production procedures. Copyright © 2011 Wiley Periodicals, Inc.

  9. Different characteristics and nucleotide binding properties of inosine monophosphate dehydrogenase (IMPDH isoforms.

    Directory of Open Access Journals (Sweden)

    Elaine C Thomas

    Full Text Available We recently reported that Inosine Monophosphate Dehydrogenase (IMPDH, a rate-limiting enzyme in de novo guanine nucleotide biosynthesis, clustered into macrostructures in response to decreased nucleotide levels and that there were differences between the IMPDH isoforms, IMPDH1 and IMPDH2. We hypothesised that the Bateman domains, which are present in both isoforms and serve as energy-sensing/allosteric modules in unrelated proteins, would contribute to isoform-specific differences and that mutations situated in and around this domain in IMPDH1 which give rise to retinitis pigmentosa (RP would compromise regulation. We employed immuno-electron microscopy to investigate the ultrastructure of IMPDH macrostructures and live-cell imaging to follow clustering of an IMPDH2-GFP chimera in real-time. Using a series of IMPDH1/IMPDH2 chimera we demonstrated that the propensity to cluster was conferred by the N-terminal 244 amino acids, which includes the Bateman domain. A protease protection assay suggested isoform-specific purine nucleotide binding characteristics, with ATP protecting IMPDH1 and AMP protecting IMPDH2, via a mechanism involving conformational changes upon nucleotide binding to the Bateman domain without affecting IMPDH catalytic activity. ATP binding to IMPDH1 was confirmed in a nucleotide binding assay. The RP-causing mutation, R224P, abolished ATP binding and nucleotide protection and this correlated with an altered propensity to cluster. Collectively these data demonstrate that (i the isoforms are differentially regulated by AMP and ATP by a mechanism involving the Bateman domain, (ii communication occurs between the Bateman and catalytic domains and (iii the RP-causing mutations compromise such regulation. These findings support the idea that the IMPDH isoforms are subject to distinct regulation and that regulatory defects contribute to human disease.

  10. Uridine monophosphate synthetase enables eukaryotic de novo NAD+ biosynthesis from quinolinic acid.

    Science.gov (United States)

    McReynolds, Melanie R; Wang, Wenqing; Holleran, Lauren M; Hanna-Rose, Wendy

    2017-07-07

    NAD + biosynthesis is an attractive and promising therapeutic target for influencing health span and obesity-related phenotypes as well as tumor growth. Full and effective use of this target for therapeutic benefit requires a complete understanding of NAD + biosynthetic pathways. Here, we report a previously unrecognized role for a conserved phosphoribosyltransferase in NAD + biosynthesis. Because a required quinolinic acid phosphoribosyltransferase (QPRTase) is not encoded in its genome, Caenorhabditis elegans are reported to lack a de novo NAD + biosynthetic pathway. However, all the genes of the kynurenine pathway required for quinolinic acid (QA) production from tryptophan are present. Thus, we investigated the presence of de novo NAD + biosynthesis in this organism. By combining isotope-tracing and genetic experiments, we have demonstrated the presence of an intact de novo biosynthesis pathway for NAD + from tryptophan via QA, highlighting the functional conservation of this important biosynthetic activity. Supplementation with kynurenine pathway intermediates also boosted NAD + levels and partially reversed NAD + -dependent phenotypes caused by mutation of pnc-1 , which encodes a nicotinamidase required for NAD + salvage biosynthesis, demonstrating contribution of de novo synthesis to NAD + homeostasis. By investigating candidate phosphoribosyltransferase genes in the genome, we determined that the conserved uridine monophosphate phosphoribosyltransferase (UMPS), which acts in pyrimidine biosynthesis, is required for NAD + biosynthesis in place of the missing QPRTase. We suggest that similar underground metabolic activity of UMPS may function in other organisms. This mechanism for NAD + biosynthesis creates novel possibilities for manipulating NAD + biosynthetic pathways, which is key for the future of therapeutics. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Novel adenosine 3',5'-cyclic monophosphate dependent protein kinases in a marine diatom

    International Nuclear Information System (INIS)

    Lin, P.P.C.; Volcani, B.E.

    1989-01-01

    Two novel adenosine 3',5'-cyclic monophosphate (cAMP) dependent protein kinases have been isolated from the diatom Cylindrotheca fusiformis. The kinases, designated I and II, are eluted from DEAE-Sephacel at 0.10 and 0.15 M NaCl. They have a high affinity for cAMP and are activated by micromolar cAMP. They exhibit maximal activity at 5 mM Mg 2+ and pH 8 with the preferred phosphate donor ATP and phosphate acceptor histone H1. They phosphorylate sea urchin sperm histone H1 on a single serine site in the sequence Arg-Lys-Gly-Ser( 32 P)-Ser-Asn-Ala-Arg and have an apparent M r of 75,000 as determined by gel filtration and sucrose density sedimentation. In the kinase I preparation a single protein band with an apparent M r of about 78,000 is photolabeled with 8-azido[ 32 P]cAMP and is also phosphorylated with [γ- 32 P]ATP in a cAMP-dependent manner, after autoradiography following sodium dodecyl sulfate gel electrophoresis. The rate of phosphorylation of the 78,000-dalton band is independent of the enzyme concentration. The results indicate that (i) these diatom cAMP-dependent protein kinases are monomeric proteins, possessing both the cAMP-binding regulatory and catalytic domains on the same polypeptide chain, (ii) the enzymes do not dissociate into smaller species upon activation by binding cAMP, and (iii) self-phosphorylation of the enzymes by an intrapeptide reaction is cAMP dependent. The two diatom cAMP kinases are refractory to the heat-stable protein kinase modulator from rabbit muscle, but they respond differently to proteolytic degradation and to inhibition by arachidonic acid and several microbial alkaloids

  12. Enzyme architecture: deconstruction of the enzyme-activating phosphodianion interactions of orotidine 5'-monophosphate decarboxylase.

    Science.gov (United States)

    Goldman, Lawrence M; Amyes, Tina L; Goryanova, Bogdana; Gerlt, John A; Richard, John P

    2014-07-16

    The mechanism for activation of orotidine 5'-monophosphate decarboxylase (OMPDC) by interactions of side chains from Gln215 and Try217 at a gripper loop and R235, adjacent to this loop, with the phosphodianion of OMP was probed by determining the kinetic parameters k(cat) and K(m) for all combinations of single, double, and triple Q215A, Y217F, and R235A mutations. The 12 kcal/mol intrinsic binding energy of the phosphodianion is shown to be equal to the sum of the binding energies of the side chains of R235 (6 kcal/mol), Q215 (2 kcal/mol), Y217 (2 kcal/mol), and hydrogen bonds to the G234 and R235 backbone amides (2 kcal/mol). Analysis of a triple mutant cube shows small (ca. 1 kcal/mol) interactions between phosphodianion gripper side chains, which are consistent with steric crowding of the side chains around the phosphodianion at wild-type OMPDC. These mutations result in the same change in the activation barrier to the OMPDC-catalyzed reactions of the whole substrate OMP and the substrate pieces (1-β-D-erythrofuranosyl)orotic acid (EO) and phosphite dianion. This shows that the transition states for these reactions are stabilized by similar interactions with the protein catalyst. The 12 kcal/mol intrinsic phosphodianion binding energy of OMP is divided between the 8 kcal/mol of binding energy, which is utilized to drive a thermodynamically unfavorable conformational change of the free enzyme, resulting in an increase in (k(cat))(obs) for OMPDC-catalyzed decarboxylation of OMP, and the 4 kcal/mol of binding energy, which is utilized to stabilize the Michaelis complex, resulting in a decrease in (K(m))(obs).

  13. In Vitro Assessment of Guanylyl Cyclase Activity of Plant Receptor Kinases

    KAUST Repository

    Raji, Misjudeen; Gehring, Christoph A

    2017-01-01

    Cyclic nucleotides such as 3′,5′-cyclic adenosine monophosphate (cAMP) and 3′,5′-cyclic guanosine monophosphate (cGMP) are increasingly recognized as key signaling molecules in plants, and a growing number of plant mononucleotide cyclases, both adenylate cyclases (ACs) and guanylate cyclases (GCs), have been reported. Catalytically active cytosolic GC domains have been shown to be part of many plant receptor kinases and hence directly linked to plant signaling and downstream cellular responses. Here we detail, firstly, methods to identify and express essential functional GC domains of receptor kinases, and secondly, we describe mass spectrometric methods to quantify cGMP generated by recombinant GCs from receptor kinases in vitro.

  14. In Vitro Assessment of Guanylyl Cyclase Activity of Plant Receptor Kinases

    KAUST Repository

    Raji, Misjudeen

    2017-05-31

    Cyclic nucleotides such as 3′,5′-cyclic adenosine monophosphate (cAMP) and 3′,5′-cyclic guanosine monophosphate (cGMP) are increasingly recognized as key signaling molecules in plants, and a growing number of plant mononucleotide cyclases, both adenylate cyclases (ACs) and guanylate cyclases (GCs), have been reported. Catalytically active cytosolic GC domains have been shown to be part of many plant receptor kinases and hence directly linked to plant signaling and downstream cellular responses. Here we detail, firstly, methods to identify and express essential functional GC domains of receptor kinases, and secondly, we describe mass spectrometric methods to quantify cGMP generated by recombinant GCs from receptor kinases in vitro.

  15. Further studies on the effect of adenosine cyclic monophosphate derivatives on cell proliferation in the jejunal crypts of rat.

    Science.gov (United States)

    Tutton, P J; Barkla, D H

    1982-01-01

    1. Cell proliferation in the jejunal crypt epithelium of rat was measured using a stathmokinetic technique. 2. Sodium butyrate was found to promote jejunal crypt cell proliferation. 3. N6, O2'-Dibutyryl cyclic adenosine monophosphate (cAMP), N6-monobutyryl-cAMP and N6-monobutyryl-8-bromo-cAMP were found to inhibit cell proliferation when compared to sodium butyrate treated tissues. 4. 8-Chlorophenylthio-cAMP was found to inhibit cell division when compared to untreated animals. 5. O2'-Monobutyryl cAMP and 8-bromo-cAMP were not found to inhibit cell proliferation.

  16. The role of NMDA receptor and nitric oxide/cyclic guanosine monophosphate pathway in the antidepressant-like effect of dextromethorphan in mice forced swimming test and tail suspension test.

    Science.gov (United States)

    Sakhaee, Ehsan; Ostadhadi, Sattar; Khan, Muhammad Imran; Yousefi, Farbod; Norouzi-Javidan, Abbas; Akbarian, Reyhaneh; Chamanara, Mohsen; Zolfaghari, Samira; Dehpour, Ahmad-Reza

    2017-01-01

    Depression is a devastating disorder which has a high impact on the wellbeing of overall society. As such, need for innovative therapeutic agents are always there. Most of the researchers focused on N-methyl-d-aspartate receptor to explore the antidepressant like activity of new therapeutic agents. Dextromethorphan is a cough suppressant agent with potential antidepressant activity reported in mouse force swimming test. Considering N-methyl-d-aspartate as a forefront in exploring antidepressant agents, here we focused to unpin the antidepressant mechanism of dextromethorphan targeting N-methyl-d-aspartate receptor induced nitric oxide-cyclic guanosine monophosphate signaling. Dextromethorphan administered at a dose of 10 and 30mg/kg i.p significantly reduced the immobility time. Interestingly, this effect of drug (30mg/kg) was inhibited when the animals were pretreated either with N-methyl-d-aspartate (75mg/kg), or l-arginine (750mg/kg) as a nitric oxide precursor and/or sildenafil (5mg/kg) as a phosphodiesterase 5 inhibitor. However, the antidepressant effect of Dextromethorphan subeffective dose (3mg/kg) was augmented when the animals were administered with either L-NG-Nitroarginine methyl ester (10mg/kg) non-specific nitric oxide synthase inhibitor, 7-Nitroindazole (30mg/kg) specific neural nitric oxide synthase inhibitor, MK-801 (0.05mg/kg) an N-methyl-d-aspartate receptor antagonist but not aminoguanidine (50mg/kg) which is specific inducible nitric oxide synthase inhibitor as compared to the drugs when administered alone. No remarkable effect on locomotor activity was observed during open field test when the drugs were administered at the above mentioned doses. Therefore, it is evident that the antidepressant like effect of Dextromethorphan is owed due to its inhibitory effect on N-methyl-d-aspartate receptor and NO- Cyclic guanosine monophosphate pathway. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. The effect of adenosine 5'-monophosphate (AMP) on tenderness, microstructure and chemical-physical index of duck breast meat.

    Science.gov (United States)

    Wang, Daoying; Deng, Shaoying; Zhang, Muhan; Geng, Zhiming; Sun, Chong; Bian, Huan; Xu, Weimin; Zhu, Yongzhi; Liu, Fang; Wu, Haihong

    2016-03-30

    Adenosine 5'-monophosphate (AMP) is often used in meat and poultry soups as a flavor enhancer (flavor modifier), or as food additives for specific nutritional purposes. Our previous research as well as evidence from others showed that actomyosin could be dissociated into myosin and actin by AMP in extracted muscle solution. However, there is no report available on the application of AMP to dissociate actomyosin and to improve meat tenderness. The objectives of this study were to evaluate the effect of AMP on duck meat tenderness and other quality traits and to explore the mechanism of the action of AMP on meat tenderness. Duck breast muscle was treated with 0, 10, 20, 30, 40 mmol L(-1) AMP at 5 °C for 10 h and examined for shear force, microstructure, actomyosin dissociation, myofibril fragmentation index (MFI), pH, water content, cooking loss, CIE* color (L*, a*, b*), inosine monophosphate (IMP) and free amino acid (FAA) contents. Results showed that shear force, cooking loss, L* and b* of the muscles significantly decreased after AMP treatment (P 0.05), and muscle shrinkage in transverse and longitudinal directions were restrained after AMP treatment. The results suggest that AMP could notably improve meat tenderness, and this effect was probably mainly through increasing muscle pH, promoting actomyosin dissociation and disrupting the Z-line; meanwhile, the conversion of AMP to IMP may contribute to the flavor of meat. © 2015 Society of Chemical Industry.

  18. The Role of Cyclic Nucleotide Signaling Pathways in Cancer: Targets for Prevention and Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Fajardo, Alexandra M.; Piazza, Gary A. [Drug Discovery Research Center, Mitchell Cancer Institute, University of South Alabama, 1660 Springhill Ave, Suite 3029, Mobile, AL 36604 (United States); Tinsley, Heather N., E-mail: htinsley@montevallo.edu [Department of Biology, Chemistry, and Mathematics, University of Montevallo, Station 6480, Montevallo, AL 35115 (United States)

    2014-02-26

    For more than four decades, the cyclic nucleotides cyclic AMP (cAMP) and cyclic GMP (cGMP) have been recognized as important signaling molecules within cells. Under normal physiological conditions, cyclic nucleotides regulate a myriad of biological processes such as cell growth and adhesion, energy homeostasis, neuronal signaling, and muscle relaxation. In addition, altered cyclic nucleotide signaling has been observed in a number of pathophysiological conditions, including cancer. While the distinct molecular alterations responsible for these effects vary depending on the specific cancer type, several studies have demonstrated that activation of cyclic nucleotide signaling through one of three mechanisms—induction of cyclic nucleotide synthesis, inhibition of cyclic nucleotide degradation, or activation of cyclic nucleotide receptors—is sufficient to inhibit proliferation and activate apoptosis in many types of cancer cells. These findings suggest that targeting cyclic nucleotide signaling can provide a strategy for the discovery of novel agents for the prevention and/or treatment of selected cancers.

  19. Identification of a novel Arabidopsis thaliana nitric oxide-binding molecule with guanylate cyclase activity in vitro

    KAUST Repository

    Mulaudzi, Takalani

    2011-09-01

    While there is evidence of nitric oxide (NO)-dependent signalling via the second messenger cyclic guanosine 3′,5′-monophosphate (cGMP) in plants, guanylate cyclases (GCs), enzymes that catalyse the formation of cGMP from guanosine 5′-triphosphate (GTP) have until recently remained elusive and none of the candidates identified to-date are NO-dependent. Using both a GC and heme-binding domain specific (H-NOX) search motif, we have identified an Arabidopsis flavin monooxygenase (At1g62580) and shown electrochemically that it binds NO, has a higher affinity for NO than for O 2 and that this molecule can generate cGMP from GTP in vitro in an NO-dependent manner. © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  20. Radiorestoring activity of few nucleotides on normal tissues of Jerusalem Artichoke after an irradiation with γ rays of 60Co

    International Nuclear Information System (INIS)

    Jonard, Robert; Bayonove, Jacqueline; Riedel, Michel.

    1978-01-01

    The nucleotides tested: adenosine triphosphate (ATP) and cyclic adenosine 3',5'-monophosphate (3',5'-cAMP), guanosine triphosphate (GTP) and cyclic guanosine 3',5'-monophosphate (3',5'-cGMP), are able to restore proliferation to irradiated (γ irradiation, 3,000 rad) Jesusalem Artichoke tissue. The 3',5'-cGMP shows the greater radiorestoring activity [fr

  1. Crystallization and preliminary X-ray crystallographic analysis of adenosine 5′-monophosphate deaminase (AMPD) from Arabidopsis thaliana in complex with coformycin 5′-phosphate

    International Nuclear Information System (INIS)

    Han, Byung Woo; Bingman, Craig A.; Mahnke, Donna K.; Sabina, Richard L.; Phillips, George N. Jr

    2005-01-01

    Adenosine 5′-monophosphate deaminase from A. thaliana has been crystallized in complex with coformycin 5′-phosphate. Diffraction data have been collected to 3.34 Å resolution. Adenosine 5′-monophosphate deaminase (AMPD) is a eukaryotic enzyme that converts adenosine 5′-monophosphate (AMP) to inosine 5′-monophosphate (IMP) and ammonia. AMPD from Arabidopsis thaliana (AtAMPD) was cloned into the baculoviral transfer vector p2Bac and co-transfected along with a modified baculoviral genome into Spodoptera frugiperda (Sf9) cells. The resulting recombinant baculovirus were plaque-purified, amplified and used to overexpress recombinant AtAMPD. Crystals of purified AtAMPD have been obtained to which coformycin 5′-phosphate, a transition-state inhibitor, is bound. Crystals belong to space group P6 2 22, with unit-cell parameters a = b = 131.325, c = 208.254 Å, α = β = 90, γ = 120°. Diffraction data were collected to 3.34 Å resolution from a crystal in complex with coformycin 5′-phosphate and to 4.05 Å resolution from a crystal of a mercury derivative

  2. Crystallization and preliminary X-ray crystallographic analysis of adenosine 5′-monophosphate deaminase (AMPD) from Arabidopsis thaliana in complex with coformycin 5′-phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Han, Byung Woo [Department of Biochemistry, University of Wisconsin-Madison, WI 53706-1544 (United States); Center for Eukaryotic Structural Genomics (CESG), University of Wisconsin-Madison, WI 53706-1549 (United States); Bingman, Craig A. [Center for Eukaryotic Structural Genomics (CESG), University of Wisconsin-Madison, WI 53706-1549 (United States); Mahnke, Donna K.; Sabina, Richard L. [Department of Biochemistry, The Medical College of Wisconsin, Milwaukee, WI 53226-4801 (United States); Phillips, George N. Jr, E-mail: phillips@biochem.wisc.edu [Department of Biochemistry, University of Wisconsin-Madison, WI 53706-1544 (United States); Center for Eukaryotic Structural Genomics (CESG), University of Wisconsin-Madison, WI 53706-1549 (United States)

    2005-08-01

    Adenosine 5′-monophosphate deaminase from A. thaliana has been crystallized in complex with coformycin 5′-phosphate. Diffraction data have been collected to 3.34 Å resolution. Adenosine 5′-monophosphate deaminase (AMPD) is a eukaryotic enzyme that converts adenosine 5′-monophosphate (AMP) to inosine 5′-monophosphate (IMP) and ammonia. AMPD from Arabidopsis thaliana (AtAMPD) was cloned into the baculoviral transfer vector p2Bac and co-transfected along with a modified baculoviral genome into Spodoptera frugiperda (Sf9) cells. The resulting recombinant baculovirus were plaque-purified, amplified and used to overexpress recombinant AtAMPD. Crystals of purified AtAMPD have been obtained to which coformycin 5′-phosphate, a transition-state inhibitor, is bound. Crystals belong to space group P6{sub 2}22, with unit-cell parameters a = b = 131.325, c = 208.254 Å, α = β = 90, γ = 120°. Diffraction data were collected to 3.34 Å resolution from a crystal in complex with coformycin 5′-phosphate and to 4.05 Å resolution from a crystal of a mercury derivative.

  3. Regulation of Maltodextrin Phosphorylase Synthesis in Escherichia coli by Cyclic Adenosine 3′, 5′-Monophosphate and Glucose1

    Science.gov (United States)

    Chao, Julie; Weathersbee, Carolyn J.

    1974-01-01

    Cyclic adenosine 3′, 5′-monophosphate (AMP) stimulates maltodextrin phosphorylase synthesis in Escherichia coli cells induced with maltose. A maximal effect occurs at 2 to 3 mM cyclic AMP. The action of cyclic AMP is specific, inasmuch as adenosine triphosphate, 3′-AMP, 5′-AMP, adenosine, and dibutyryl cyclic AMP are inactive. Glucose, α-methyl glucoside, 2-deoxyglucose, and pyridoxal 5′-phosphate repress maltodextrin phosphorylase synthesis. This repression is reversed by cyclic AMP. The action of cyclic AMP appears to be at the transcriptional level, since cyclic AMP fails to stimulate phosphorylase production in induced cells in which messenger ribonucleic acid synthesis has been arrested by rifampin or by inducer removal. The two other enzymes involved in the metabolism of maltose, amylomaltase and maltose permease, are also induced in this strain of E. coli and affected by glucose and cyclic AMP in a manner similar to phosphorylase. PMID:4358043

  4. Stereoselective aminoacylation of a dinucleoside monophosphate by the imidazolides of DL-alanine and N-(tert-butoxycarbonyl)-DL-alanine

    Science.gov (United States)

    Profy, A. T.; Usher, D. A.

    1984-01-01

    The aminoacylation of diinosine monophosphate was studied experimentally. When the acylating agent was the imidazolide of N-(tert-butoxycarbonyl)-DL-alanine, a 40 percent enantiomeric excess of the isomer was incorporated at the 2' site and the positions of equilibrium for the reversible 2'-3' migration reaction differed for the D and L enantiomers. The reactivity of the nucleoside hydroxyl groups was found to decrease on the order 2'(3') less than internal 2' and less than 5', and the extent of the reaction was affected by the concentration of the imidazole buffer. Reaction of IpI with imidazolide of unprotected DL-alanine, by contrast, led to an excess of the D isomer at the internal 2' site. Finally, reaction with the N-carboxy anhydride of DL-alanine occurred without stereoselection. These results are found to be relevant to the study of the evolution of optical chemical activity and the origin of genetically directed protein synthesis.

  5. Ca 2+ signaling by plant Arabidopsis thaliana Pep peptides depends on AtPepR1, a receptor with guanylyl cyclase activity, and cGMP-activated Ca 2+ channels

    KAUST Repository

    Qia, Zhi

    2010-11-18

    A family of peptide signaling molecules (AtPeps) and their plasma membrane receptor AtPepR1 are known to act in pathogendefense signaling cascades in plants. Little is currently known about the molecular mechanisms that link these signaling peptides and their receptor, a leucine-rich repeat receptor-like kinase, to downstream pathogen-defense responses. We identify some cellular activities of these molecules that provide the context for a model for their action in signaling cascades. AtPeps activate plasma membrane inwardly conducting Ca 2+ permeable channels in mesophyll cells, resulting in cytosolic Ca 2+ elevation. This activity is dependent on their receptor as well as a cyclic nucleotide-gated channel (CNGC2). We also show that the leucine-rich repeat receptor- like kinase receptor AtPepR1 has guanylyl cyclase activity, generating cGMP from GTP, and that cGMP can activate CNGC2- dependent cytosolic Ca 2+ elevation. AtPep-dependent expression of pathogen-defense genes (PDF1.2, MPK3, and WRKY33) is mediated by the Ca 2+ signaling pathway associated with AtPep peptides and their receptor. The work presented here indicates that extracellular AtPeps, which can act as danger-associated molecular patterns, signal by interaction with their receptor, AtPepR1, a plasma membrane protein that can generate cGMP. Downstream from AtPep and AtPepR1 in a signaling cascade, the cGMP-activated channel CNGC2 is involved in AtPep- and AtPepR1-dependent inward Ca 2+ conductance and resulting cytosolic Ca 2+ elevation. The signaling cascade initiated by AtPeps leads to expression of pathogen- defense genes in a Ca 2+-dependent manner.

  6. "cAMP sponge": a buffer for cyclic adenosine 3', 5'-monophosphate.

    Directory of Open Access Journals (Sweden)

    Konstantinos Lefkimmiatis

    Full Text Available BACKGROUND: While intracellular buffers are widely used to study calcium signaling, no such tool exists for the other major second messenger, cyclic AMP (cAMP. METHODS/PRINCIPAL FINDINGS: Here we describe a genetically encoded buffer for cAMP based on the high-affinity cAMP-binding carboxy-terminus of the regulatory subunit RIbeta of protein kinase A (PKA. Addition of targeting sequences permitted localization of this fragment to the extra-nuclear compartment, while tagging with mCherry allowed quantification of its expression at the single cell level. This construct (named "cAMP sponge" was shown to selectively bind cAMP in vitro. Its expression significantly suppressed agonist-induced cAMP signals and the downstream activation of PKA within the cytosol as measured by FRET-based sensors in single living cells. Point mutations in the cAMP-binding domains of the construct rendered the chimera unable to bind cAMP in vitro or in situ. Cyclic AMP sponge was fruitfully applied to examine feedback regulation of gap junction-mediated transfer of cAMP in epithelial cell couplets. CONCLUSIONS: This newest member of the cAMP toolbox has the potential to reveal unique biological functions of cAMP, including insight into the functional significance of compartmentalized signaling events.

  7. The effect of resveratrol on beta amyloid-induced memory impairment involves inhibition of phosphodiesterase-4 related signaling.

    Science.gov (United States)

    Wang, Gang; Chen, Ling; Pan, Xiaoyu; Chen, Jiechun; Wang, Liqun; Wang, Weijie; Cheng, Ruochuan; Wu, Fan; Feng, Xiaoqing; Yu, Yingcong; Zhang, Han-Ting; O'Donnell, James M; Xu, Ying

    2016-04-05

    Resveratrol, a natural polyphenol found in red wine, has wide spectrum of pharmacological properties including antioxidative and antiaging activities. Beta amyloid peptides (Aβ) are known to involve cognitive impairment, neuroinflammatory and apoptotic processes in Alzheimer's disease (AD). Activation of cAMP and/or cGMP activities can improve memory performance and decrease the neuroinflammation and apoptosis. However, it remains unknown whether the memory enhancing effect of resveratrol on AD associated cognitive disorders is related to the inhibition of phosphodiesterase 4 (PDE4) subtypes and subsequent increases in intracellular cAMP and/or cGMP activities. This study investigated the effect of resveratrol on Aβ1-42-induced cognitive impairment and the participation of PDE4 subtypes related cAMP or cGMP signaling. Mice microinfused with Aβ1-42 into bilateral CA1 subregions displayed learning and memory impairment, as evidenced by reduced memory acquisition and retrieval in the water maze and retention in the passive avoidance tasks; it was also significant that neuroinflammatory and pro-apoptotic factors were increased in Aβ1-42-treated mice. Aβ1-42-treated mice also increased in PDE4A, 4B and 4D expression, and decreased in PKA level. However, PKA inhibitor H89, but not PKG inhibitor KT5823, prevented resveratrol's effects on these parameters. Resveratrol also reversed Aβ1-42-induced decreases in phosphorylated cAMP response-element binding protein (pCREB), brain derived neurotrophic factor (BDNF) and anti-apoptotic factor BCl-2 expression, which were reversed by H89. These findings suggest that resveratrol reversing Aβ-induced learning and memory disorder may involve the regulation of neuronal inflammation and apoptosis via PDE4 subtypes related cAMP-CREB-BDNF signaling.

  8. Hypoxanthine-guanine phosphoribosyltransferase and inosine 5’-monophosphate dehydrogenase activities in three mammalian species: aquatic (Mirounga angustirostris, semiaquatic (Lontra longicaudis annectens and terrestrial (Sus scrofa

    Directory of Open Access Journals (Sweden)

    Myrna eBarjau Perez-Milicua

    2015-07-01

    Full Text Available Aquatic and semiaquatic mammals have the capacity of breath hold (apnea diving. Northern elephant seals (Mirounga angustirostris have the ability to perform deep and long duration dives; during a routine dive, adults can hold their breath for 25 min. Neotropical river otters (Lontra longicaudis annectens can hold their breath for about 30 sec. Such periods of apnea may result in reduced oxygen concentration (hypoxia and reduced blood supply (ischemia to tissues. Production of adenosine 5’-triphosphate (ATP requires oxygen, and most mammalian species, like the domestic pig (Sus scrofa, are not adapted to tolerate hypoxia and ischemia, conditions that result in ATP degradation. The objective of this study was to explore the differences in purine synthesis and recycling in erythrocytes and plasma of three mammalian species adapted to different environments: aquatic (northern elephant seal (n=11, semiaquatic (neotropical river otter (n=4 and terrestrial (domestic pig (n=11. Enzymatic activity of hypoxanthine-guanine phosphoribosyltransferase (HGPRT was determined by spectrophotometry, and activity of inosine 5’-monophosphate dehydrogenase (IMPDH and the concentration of hypoxanthine (HX, inosine 5’-monophosphate (IMP, adenosine 5’-monophosphate (AMP, adenosine 5’-diphosphate (ADP, ATP, guanosine 5’-diphosphate (GDP, guanosine 5’-triphosphate (GTP, and xanthosine 5’-monophosphate (XMP were determined by high-performance liquid chromatography (HPLC. The activities of HGPRT and IMPDH and the concentration of HX, IMP, AMP, ADP, ATP, GTP and XMP in erythrocytes of domestic pigs were higher than in erythrocytes of northern elephant seals and river otters. These results suggest that under basal conditions (no diving, sleep apnea or exercise, aquatic and semiaquatic mammals have less purine mobilization than their terrestrial counterparts.

  9. Signal Words

    Science.gov (United States)

    SIGNAL WORDS TOPIC FACT SHEET NPIC fact sheets are designed to answer questions that are commonly asked by the ... making decisions about pesticide use. What are Signal Words? Signal words are found on pesticide product labels, ...

  10. Orotidine-5'-monophosphate decarboxylase catalysis: Kinetic isotope effects and the state of hybridization of a bound transition-state analogue

    Energy Technology Data Exchange (ETDEWEB)

    Acheson, S.A.; Bell, J.B.; Jones, M.E.; Wolfenden, R. (Univ. of North Carolina School of Medicine, Chapel Hill (USA))

    1990-04-03

    The enzymatic decarboxylation of orotidine 5'-monophosphate may proceed by an addition-elimination mechanism involving a covalently bound intermediate or by elimination of CO2 to generate a nitrogen ylide. In an attempt to distinguish between these two alternatives, 1-(phosphoribosyl)barbituric acid was synthesized with 13C at the 5-position. Interaction of this potential transition-state analogue inhibitor with yeast orotidine-5'-monophosphate decarboxylase resulted in a small (0.6 ppm) downfield displacement of the C-5 resonance, indicating no rehybridization of the kind that might have been expected to accompany 5,6-addition of an enzyme nucleophile. When the substrate orotidine 5'-monophosphate was synthesized with deuterium at C-5, no significant change in kcat (H/D = 0.99 +/- 0.06) or kcat/KM (H/D = 1.00 +/- 0.06) was found to result, suggesting that C-5 does not undergo significant changes in geometry before or during the step that determines the rate of the catalytic process. These results are consistent with a nitrogen ylide mechanism and offer no support for the intervention of covalently bound intermediates in the catalytic process.

  11. A new sensitive 32P-postlabeling assay based on the specific enzymatic conversion of bulky DNA lesions to radiolabeled dinucleotides and nucleoside 5'-monophosphates

    International Nuclear Information System (INIS)

    Randerath, Kurt; Randerath, Erika; Danna, T.F.; Van Golen, K.L.; Putman, K.L.

    1989-01-01

    A new sensitive 32 P-postlabelling assay for DNA adducts has been developed. When DNA containing bulky adducts, X 1 , X 2 , .....X n , is digested with nuclease P1 at pH 5, normal nucleotides are released as 5'-monophosphates, pN, while adducts are excised as 5'-phosphorylated dinucleotides, pX i pN, because inter-nucleotide linkages on the 3' side of X resist attack by nuclease P1. Addition of prostatic acid phosphatase to such a digest results in 5'-dephosphorylation of the nucleotides to normal nucleosides, N, and adducted dinucleotides, X i pN, carrying a 5'-terminal free hydroxyl group. The dinucleotides but not nucleosides are converted to 5'- 32 P-labeled dinucleotides,[ 32 P]pX i pN, by T4 polynucleotide kinase-catalyzed [ 32 P]posphate transfer from [γ- 32 P]ATP. Upon mapping on polyethyleneimine-cellulose anion-exchange TLC, the labeled dinucleotide adducts produce characteristic autoradiographic fingerprints. Alternatively, they are further digested with snake venom phosphodiesterase to yield 5'-monophosphates, [ 32 P]pX i and pN. TLC profiles of the monophosphate adducts are distinct from those of the dinucleotides. These reactions provide the basis of the new 32 P-postlabeling scheme, which is compared in this paper with a previously reported protocol yielding adducts in the form of 5'- 32 P-labeled 3',5'-bisphosphates, [ 32 P]pX i p. (author)

  12. Application of graphene-ionic liquid-chitosan composite-modified carbon molecular wire electrode for the sensitive determination of adenosine-5′-monophosphate

    International Nuclear Information System (INIS)

    Shi, Fan; Gong, Shixing; Xu, Li; Zhu, Huanhuan; Sun, Zhenfan; Sun, Wei

    2013-01-01

    In this paper, a graphene (GR) ionic liquid (IL) 1-octyl-3-methylimidazolium hexafluorophosphate and chitosan composite-modified carbon molecular wire electrode (CMWE) was fabricated by a drop-casting method and further applied to the sensitive electrochemical detection of adenosine-5′-monophosphate (AMP). CMWE was prepared with diphenylacetylene (DPA) as the modifier and the binder. The properties of modified electrode were examined by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Electrochemical behaviors of AMP was carefully investigated with enhanced responses appeared, which was due to the presence of GR-IL composite on the electrode surface with excellent electrocatalytic ability. A well-defined oxidation peak of AMP appeared at 1.314 V and the electrochemical parameters were calculated by electrochemical methods. Under the selected conditions, the oxidation peak current of AMP was proportional to its concentration in the range from 0.01 μM to 80.0 μM with the detection limit as 3.42 nM (3σ) by differential pulse voltammetry. The proposed method exhibited good selectivity and was applied to the detection of vidarabine monophosphate injection samples with satisfactory results. - Highlights: • A graphene, ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate and chitosan composite were prepared. • Composite-modified carbon molecular wire electrode was fabricated and characterized. • A sensitive electrochemical method for the detection of adenosine-5′-monophosphate was established

  13. Application of graphene-ionic liquid-chitosan composite-modified carbon molecular wire electrode for the sensitive determination of adenosine-5′-monophosphate

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Fan [Key Laboratory of Tropical Medicinal Plant Chemistry of Ministry of Education, College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China); Gong, Shixing; Xu, Li; Zhu, Huanhuan [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Sun, Zhenfan [Key Laboratory of Tropical Medicinal Plant Chemistry of Ministry of Education, College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China); Sun, Wei, E-mail: swyy26@hotmail.com [Key Laboratory of Tropical Medicinal Plant Chemistry of Ministry of Education, College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 (China)

    2013-12-01

    In this paper, a graphene (GR) ionic liquid (IL) 1-octyl-3-methylimidazolium hexafluorophosphate and chitosan composite-modified carbon molecular wire electrode (CMWE) was fabricated by a drop-casting method and further applied to the sensitive electrochemical detection of adenosine-5′-monophosphate (AMP). CMWE was prepared with diphenylacetylene (DPA) as the modifier and the binder. The properties of modified electrode were examined by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Electrochemical behaviors of AMP was carefully investigated with enhanced responses appeared, which was due to the presence of GR-IL composite on the electrode surface with excellent electrocatalytic ability. A well-defined oxidation peak of AMP appeared at 1.314 V and the electrochemical parameters were calculated by electrochemical methods. Under the selected conditions, the oxidation peak current of AMP was proportional to its concentration in the range from 0.01 μM to 80.0 μM with the detection limit as 3.42 nM (3σ) by differential pulse voltammetry. The proposed method exhibited good selectivity and was applied to the detection of vidarabine monophosphate injection samples with satisfactory results. - Highlights: • A graphene, ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate and chitosan composite were prepared. • Composite-modified carbon molecular wire electrode was fabricated and characterized. • A sensitive electrochemical method for the detection of adenosine-5′-monophosphate was established.

  14. Bronchodilator responses after methacholine and adenosine 5'-monophosphate (AMP) challenges in children with asthma: their relationships with eosinophil markers.

    Science.gov (United States)

    Yoo, Young; Seo, Sung Chul; Kim, Young Il; Chung, Bo Hyun; Song, Dae Jin; Choung, Ji Tae

    2012-09-01

    Bronchodilator responsiveness (BDR) and eosinophilic inflammation are characteristic features of asthma. Objective. The aim of this study was to compare the relationships of BDR after methacholine challenge or adenosine 5'-monophosphate (AMP) challenge to blood eosinophil markers in children with asthma. Methacholine and AMP challenges were performed on 69 children with mild intermittent to moderate persistent asthma. BDR was calculated as the change in forced expiratory volume in 1 second, expressed as percentage change of the value immediately after the each challenge and the value after inhalation of salbutamol. Serum total IgE levels, blood eosinophil counts, and serum eosinophil cationic protein (ECP) levels were determined for each subject. A positive relationship between serum total IgE levels and BDR was found only after the AMP challenge (R(2) = 0.345, p = .001) rather than after the methacholine challenge (R(2) = 0.007, p = .495). Peripheral blood eosinophil counts correlated more significantly with BDR after AMP challenge (R(2) = 0.212, p = .001) than BDR after methacholine challenge (R(2) = 0.002, p = .724). Both BDR after methacholine challenge (R(2) = 0.063, p = .038) and BDR after AMP challenge (R(2) = 0.192, p = .001) were significantly correlated with serum ECP levels. BDR after AMP challenge may be more closely related to eosinophilic inflammation, compared with that after methacholine challenge.

  15. Investigation of the enzymatic mechanism of yeast orotidine-5'-monophosphate decarboxylase using 13C kinetic isotope effects

    International Nuclear Information System (INIS)

    Smiley, J.A.; Bell, J.B.; Jones, M.E.; Paneth, P.; O'Leary, M.H.

    1991-01-01

    Orotidine-5'-monophosphate decarboxylase (ODCase) from Saccharomyces cerevisiae displays an observed 13 C kinetic isotope effect of 1.0247 ± 0.0008 at 25 C, pH 6.8. The observed isotope effect is sensitive to changes in the reaction medium, such as pH, temperature, or glycerol content. The value of 1.0494 ± 0.0006 measured at pH 4.0, 25 C, is not altered significantly by temperature or glycerol, and thus the intrinsic isotope effect for the reaction is apparently being observed under these conditions and decarboxylation is almost entirely rate-determining. These data require a catalytic mechanism with freely reversible binding and one in which a very limited contribution to the overall rate is made by chemical steps preceding decarboxylation; the zwitterion mechanism of Beak and Siegel, which involves only protonation of the pyrimidine ring, is such a mechanism. With use of an intrinsic isotope effect of 1.05, a partitioning factor of less than unity is calculated for ODCase at pH 6.0, 25 C. A quantitative kinetic analysis using this result excludes the possibility of an enzymatic mechanism involving covalent attachment of an enzyme nucleophile to C-5 of the pyrimidine ring. These data fit a kinetic model in which an enzyme proton necessary for catalysis is titrated at high pH, thus providing evidence for the catalytic mechanism of Beak and Siegal

  16. Mechanism of adenylate kinase. Dose adenosine 5'-triphosphate bind to the adenosine 5'-monophosphate site

    Energy Technology Data Exchange (ETDEWEB)

    Shyy, Y.J.; Tian, G.; Tsai, M.D.

    1987-10-06

    Although the subtrate binding properties of adenylate kinase (AK) have been studied extensively by various biochemical and biophysical techniques, it remains controversial whether uncomplexed adenosine 5'-triphosphate (ATP) binds to the adenosine 5'-monophosphate (AMP) site of AK. The authors present two sets of experiments which argue against binding of ATP to the AMP site. (a) /sup 31/P nuclear magnetic resonance titration of ATP with AK indicated a 1:1 stoichiometry on the basis of changes in coupling constants and line widths. This ruled out binding of ATP to both sites. (b) ATP and MgATP were found to behave similarly by protecting AK from spontaneous inactivation while AMP showed only a small degree of protection. Such inactivation could also be protected or reversed by dithioerythritol and is most likely due to oxidation of sulfhydryl groups, one of which (cysteine-25) is located near the MgATP site. The results support binding of ATP to the MgATP site predominantly, instead of the AMP site, in the absence of Mg/sup 2 +/.

  17. Barrier-free proton transfer in the valence anion of 2'-deoxyadenosine-5'-monophosphate. II. A computational study

    Science.gov (United States)

    Kobyłecka, Monika; Gu, Jiande; Rak, Janusz; Leszczynski, Jerzy

    2008-01-01

    The propensity of four representative conformations of 2'-deoxyadenosine-5'-monophosphate (5'-dAMPH) to bind an excess electron has been studied at the B3LYP /6-31++G(d,p) level. While isolated canonical adenine does not support stable valence anions in the gas phase, all considered neutral conformations of 5'-dAMPH form adiabatically stable anions. The type of an anionic 5'-dAMPH state, i.e., the valence, dipole bound, or mixed (valence/dipole bound), depends on the internal hydrogen bond(s) pattern exhibited by a particular tautomer. The most stable anion results from an electron attachment to the neutral syn-south conformer. The formation of this anion is associated with a barrier-free proton transfer triggered by electron attachment and the internal rotation around the C4'-C5' bond. The adiabatic electron affinity of the a&barbelow;south-syn anion is 1.19eV, while its vertical detachment energy is 1.89eV. Our results are compared with the photoelectron spectrum (PES) of 5'-dAMPH- measured recently by Stokes et al., [J. Chem. Phys. 128, 044314 (2008)]. The computational VDE obtained for the most stable anionic structure matches well with the experimental electron binding energy region of maximum intensity. A further understanding of DNA damage might require experimental and computational studies on the systems in which purine nucleotides are engaged in hydrogen bonding.

  18. Differential Sensitivities of Fast- and Slow-Cycling Cancer Cells to Inosine Monophosphate Dehydrogenase 2 Inhibition by Mycophenolic Acid

    Science.gov (United States)

    Chen, Kan; Cao, Wanlu; Li, Juan; Sprengers, Dave; Hernanda, Pratika Y; Kong, Xiangdong; van der Laan, Luc JW; Man, Kwan; Kwekkeboom, Jaap; Metselaar, Herold J; Peppelenbosch, Maikel P; Pan, Qiuwei

    2015-01-01

    As uncontrolled cell proliferation requires nucleotide biosynthesis, inhibiting enzymes that mediate nucleotide biosynthesis constitutes a rational approach to the management of oncological diseases. In practice, however, results of this strategy are mixed and thus elucidation of the mechanisms by which cancer cells evade the effect of nucleotide biosynthesis restriction is urgently needed. Here we explored the notion that intrinsic differences in cancer cell cycle velocity are important in the resistance toward inhibition of inosine monophosphate dehydrogenase (IMPDH) by mycophenolic acid (MPA). In short-term experiments, MPA treatment of fast-growing cancer cells effectively elicited G0/G1 arrest and provoked apoptosis, thus inhibiting cell proliferation and colony formation. Forced expression of a mutated IMPDH2, lacking a binding site for MPA but retaining enzymatic activity, resulted in complete resistance of cancer cells to MPA. In nude mice subcutaneously engrafted with HeLa cells, MPA moderately delayed tumor formation by inhibiting cell proliferation and inducing apoptosis. Importantly, we developed a lentiviral vector–based Tet-on label-retaining system that enables to identify, isolate and functionally characterize slow-cycling or so-called label-retaining cells (LRCs) in vitro and in vivo. We surprisingly found the presence of LRCs in fast-growing tumors. LRCs were superior in colony formation, tumor initiation and resistance to MPA as compared with fast-cycling cells. Thus, the slow-cycling compartment of cancer seems predominantly responsible for resistance to MPA. PMID:26467706

  19. Experimental measurement and modelling of solubility of inosine-5′-monophosphate disodium in pure and mixed solvents

    International Nuclear Information System (INIS)

    Zou, Fengxia; Zhuang, Wei; Wu, Jinglan; Zhou, Jingwei; Liu, Qiyan; Chen, Yong; Xie, Jingjing; Zhu, Chenjie; Guo, Ting; Ying, Hanjie

    2014-01-01

    Graphical abstract: - Highlights: • Solubility of 5′-IMPNa 2 in various solvents was studied for the first time. • The solubility could be ranked as follows: water > methanol > ethanol > acetone. • Modified Apelblat equation gave the best correlating results. • Mixing Gibbs free energies, enthalpies, and entropies were predicted. • Solubility data and equations can optimise the crystallization conditions. - Abstract: The solubility of biological chemicals in solvents provide important fundamental data and is generally considered as an essential factor in the design of crystallization processes. The equilibrium solubility data of inosine-5′-monophosphate disodium (5′-IMPNa 2 ) in water, methanol, ethanol, acetone, as well as in the solvent mixtures (methanol + water, ethanol + water, acetone + water), were measured by an isothermal method at temperatures ranging from (293.15 to 313.15) K. The measured data in pure and mixed solvents were then modelled using the modified Apelblat equation, van’t Hoff equation, λh equation, ideal model and the Wilson model. The modified Apelblat equation showed the best modelling results, and it was therefore used to predict the mixing Gibbs free energies, enthalpies, and entropies of 5′-IMPNa 2 in pure and binary solvents. The positive values of the calculated partial molar Gibbs free energies indicated the variations in the solubility trends of 5′-IMPNa 2 . Water and ethanol (in the binary mixture with water) were found to be the most effective solvent and anti-solvent, respectively

  20. cGMP inhibition of type 3 phosphodiesterase is the major mechanism by which C-type natriuretic peptide activates CFTR in the shark rectal gland

    NARCIS (Netherlands)

    H.R. de Jonge (Hugo); B.C. Tilly (Bernard); B.M. Hogema (Boris); D.J. Pfau (Daniel); C.A. Kelley (Catherine); M.H. Kelley (Megan); A.M. Melita (August); M.T. Morris (Montana); M.S. Viola (Maria); J.N. Forrest Jr. (John)

    2014-01-01

    textabstractThe in vitro perfused rectal gland of the dogfish shark (Squalus acanthias) and filter-grown monolayers of primary cultures of shark rectal gland (SRG) epithelial cells were used to analyze the signal transduction pathway by which C-type natriuretic peptide (CNP) stimulates chloride

  1. Dysfunctional nitric oxide signalling increases risk of myocardial infarction.

    Science.gov (United States)

    Erdmann, Jeanette; Stark, Klaus; Esslinger, Ulrike B; Rumpf, Philipp Moritz; Koesling, Doris; de Wit, Cor; Kaiser, Frank J; Braunholz, Diana; Medack, Anja; Fischer, Marcus; Zimmermann, Martina E; Tennstedt, Stephanie; Graf, Elisabeth; Eck, Sebastian; Aherrahrou, Zouhair; Nahrstaedt, Janja; Willenborg, Christina; Bruse, Petra; Brænne, Ingrid; Nöthen, Markus M; Hofmann, Per; Braund, Peter S; Mergia, Evanthia; Reinhard, Wibke; Burgdorf, Christof; Schreiber, Stefan; Balmforth, Anthony J; Hall, Alistair S; Bertram, Lars; Steinhagen-Thiessen, Elisabeth; Li, Shu-Chen; März, Winfried; Reilly, Muredach; Kathiresan, Sekar; McPherson, Ruth; Walter, Ulrich; Ott, Jurg; Samani, Nilesh J; Strom, Tim M; Meitinger, Thomas; Hengstenberg, Christian; Schunkert, Heribert

    2013-12-19

    Myocardial infarction, a leading cause of death in the Western world, usually occurs when the fibrous cap overlying an atherosclerotic plaque in a coronary artery ruptures. The resulting exposure of blood to the atherosclerotic material then triggers thrombus formation, which occludes the artery. The importance of genetic predisposition to coronary artery disease and myocardial infarction is best documented by the predictive value of a positive family history. Next-generation sequencing in families with several affected individuals has revolutionized mutation identification. Here we report the segregation of two private, heterozygous mutations in two functionally related genes, GUCY1A3 (p.Leu163Phefs*24) and CCT7 (p.Ser525Leu), in an extended myocardial infarction family. GUCY1A3 encodes the α1 subunit of soluble guanylyl cyclase (α1-sGC), and CCT7 encodes CCTη, a member of the tailless complex polypeptide 1 ring complex, which, among other functions, stabilizes soluble guanylyl cyclase. After stimulation with nitric oxide, soluble guanylyl cyclase generates cGMP, which induces vasodilation and inhibits platelet activation. We demonstrate in vitro that mutations in both GUCY1A3 and CCT7 severely reduce α1-sGC as well as β1-sGC protein content, and impair soluble guanylyl cyclase activity. Moreover, platelets from digenic mutation carriers contained less soluble guanylyl cyclase protein and consequently displayed reduced nitric-oxide-induced cGMP formation. Mice deficient in α1-sGC protein displayed accelerated thrombus formation in the microcirculation after local trauma. Starting with a severely affected family, we have identified a link between impaired soluble-guanylyl-cyclase-dependent nitric oxide signalling and myocardial infarction risk, possibly through accelerated thrombus formation. Reversing this defect may provide a new therapeutic target for reducing the risk of myocardial infarction.

  2. [Signal transudation pathways in parietal cells of the gastric mucosa in experimental stomach ulcer].

    Science.gov (United States)

    Ostapchenko, L I; Drobins'ka, O V; Chaĭka, V O; Bohun, L I; Bohdanova, O V; Kot, L I; Haĭda, L M

    2009-01-01

    The goal of the presented work was the research of signal transduction mechanism in the rat gastric parietal cells under stomach ulcer conditions. In these cells activation of adenylate cyclase (increase of cAMP level and proteinkinase A activity) and phosphoinositide (increases [Ca2+]i; cGMP and phoshatidylinocitole levels; proteinkinase C, proteinkinase G, and calmodulin-dependent-proteinkinase activity) of signals pathway was shown. An increase of plasma membrane phospholipids (PC, PS, PE, PI, LPC) level was shown. Under conditions of influence of the stress factor the membran enzymes activity (H+, K+ -ATPase, 5'-AMPase, Na+, K+ -ATPase, Ca2+, Mg2+ -ATPase and H+, K+ -ATPase) was considerably increased. The intensification of lipid peroxidation processes in rats was demonstrated.

  3. 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.

  4. The crucial role of cyclic GMP in the eclosion hormone mediated signal transduction in the silkworm metamorphoses.

    Science.gov (United States)

    Shibanaka, Y; Hayashi, H; Okada, N; Fujita, N

    1991-10-31

    The signal transduction of the peptide, eclosion hormone, in the silkworm Bombyx mori appears to be mediated via the second messenger cyclic GMP throughout their life cycle. Injection of 8-bromo-cGMP induced the ecdysis behavior in pharate adults with similar latency to eclosion hormone-induced ecdysis; the moulting occurred 50-70 min after the injection. The potency of 8Br-cGMP was 10(2) fold higher than that of cGMP and the efficacy was increased by the co-injection of the phosphodiesterase inhibitor IBMX. On the other hand, in the silkworm pupal ecdysis the eclosion hormone and also 8Br-cGMP induced the moulting behavior in a dose-dependent manner. The adult development of the ability to respond to 8Br-cGMP took place concomitantly with the response to the eclosion hormone. Both the developmental time courses were shifted by a shift of light and dark cycles. Accordingly, the sensitivities to the peptide and cyclic nucleotide developed correspondently under the light and dark circadian rhythm. Thus throughout the silkworm life cycle, eclosion hormone is effective to trigger the ecdysis behavior and cGMP plays a crucial role as the second messenger in the eclosion hormone-mediated signal transduction.

  5. Cyclic GMP-AMP as an Endogenous Second Messenger in Innate Immune Signaling by Cytosolic DNA.

    Science.gov (United States)

    Kato, Kazuki; Omura, Hiroki; Ishitani, Ryuichiro; Nureki, Osamu

    2017-06-20

    The innate immune system functions as the first line of defense against invading bacteria and viruses. In this context, the cGAS/STING [cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase/STING] signaling axis perceives the nonself DNA associated with bacterial and viral infections, as well as the leakage of self DNA by cellular dysfunction and stresses, to elicit the host's immune responses. In this pathway, the noncanonical cyclic dinucleotide 2',3'-cyclic GMP-AMP (2',3'-cGAMP) functions as a second messenger for signal transduction: 2',3'-cGAMP is produced by the enzyme cGAS upon its recognition of double-stranded DNA, and then the 2',3'-cGAMP is recognized by the receptor STING to induce the phosphorylation of downstream factors, including TBK1 (TANK binding kinase 1) and IRF3 (interferon regulatory factor 3). Numerous crystal structures of the components of this cGAS/STING signaling axis have been reported and these clarify the structural basis for their signal transduction mechanisms. In this review, we summarize recent progress made in the structural dissection of this signaling pathway and indicate possible directions of forthcoming research.

  6. The Arabidopsis thiamin-deficient mutant pale green1 lacks thiamin monophosphate phosphatase of the vitamin B1 biosynthesis pathway.

    Science.gov (United States)

    Hsieh, Wei-Yu; Liao, Jo-Chien; Wang, Hsin-Tzu; Hung, Tzu-Huan; Tseng, Ching-Chih; Chung, Tsui-Yun; Hsieh, Ming-Hsiun

    2017-07-01

    Thiamin diphosphate (TPP, vitamin B 1 ) is an essential coenzyme present in all organisms. Animals obtain TPP from their diets, but plants synthesize TPPde novo. We isolated and characterized an Arabidopsis pale green1 (pale1) mutant that contained higher concentrations of thiamin monophosphate (TMP) and less thiamin and TPP than the wild type. Supplementation with thiamin, but not the thiazole and pyrimidine precursors, rescued the mutant phenotype, indicating that the pale1 mutant is a thiamin-deficient mutant. Map-based cloning and whole-genome sequencing revealed that the pale1 mutant has a mutation in At5g32470 encoding a TMP phosphatase of the TPP biosynthesis pathway. We further confirmed that the mutation of At5g32470 is responsible for the mutant phenotypes by complementing the pale1 mutant with constructs overexpressing full-length At5g32470. Most plant TPP biosynthetic enzymes are located in the chloroplasts and cytosol, but At5g32470-GFP localized to the mitochondrion of the root, hypocotyl, mesophyll and guard cells of the 35S:At5g32470-GFP complemented plants. The subcellular localization of a functional TMP phosphatase suggests that the complete vitamin B1 biosynthesis pathway may involve the chloroplasts, mitochondria and cytosol in plants. Analysis of PALE1 promoter-uidA activity revealed that PALE1 is mainly expressed in vascular tissues of Arabidopsis seedlings. Quantitative RT-PCR analysis of TPP biosynthesis genes and genes encoding the TPP-dependent enzymes pyruvate dehydrogenase, α-ketoglutarate dehydrogenase and transketolase revealed that the transcript levels of these genes were upregulated in the pale1 mutant. These results suggest that endogenous levels of TPP may affect the expression of genes involved in TPP biosynthesis and TPP-dependent enzymes. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  7. Adenosine monophosphate is not superior to histamine for bronchial provocation test for assessment of asthma control and symptoms.

    Science.gov (United States)

    Wu, Fan; Guan, Wei-Jie; Gao, Yi; An, Jia-Ying; Xie, Yan-Qing; Liu, Wen-Ting; Yu, Xin-Xin; Zheng, Jin-Ping

    2017-07-01

    Adenosine monophosphate (AMP) may reflect airway inflammation and hyperresponsiveness, but relationship between AMP and histamine (His, a conventional stimulus) bronchial provocation test (BPT) in asthma is not fully elucidated. To compare both BPTs and determine their utility in reflecting changes of asthmatic symptoms. BPTs were performed in a cross-over fashion, at 2-4 day intervals. Cumulative doses eliciting 20% FEV 1 fall (PD 20 FEV 1 ), diagnostic performance and adverse events (AEs) were compared. Patients with PD 20 FEV 1 lower than geometric mean were defined as responders, otherwise poor responders. Patients with uncontrolled and partly controlled asthma, who maintained their original inhaled corticosteroids therapy, underwent reassessment of airway responsiveness and asthmatic symptoms 3 and 6 months after. Nineteen uncontrolled, 22 partly controlled and 19 controlled asthmatic patients and 24 healthy subjects were recruited. Lower PD 20 FEV 1 geometric means were associated with poorer asthma control in His-BPT (0.424 μmol vs 1.684 μmol vs 3.757 μmol), but not AMP-BPT (11.810 μmol vs 7.781 μmol vs 10.220 μmol). Both BPTs yielded similar overall diagnostic performance in asthma (area under curve: 0.842 in AMP-BPT vs 0.850 in His-BPT). AEs, including wheezing and tachypnea, were similar and mild. Ten patients with uncontrolled and 10 partly controlled asthma were followed-up. At months 3 and 6, we documented an increase in PD 20 FEV 1 -AMP and PD 20 FEV 1 -His, which did not correlate with reduction asthmatic symptom scores. This overall applied in responders and poor responders of AMP-BPT and His-BPT. Despite higher screening capacity of well-controlled asthma, AMP-BPT confers similar diagnostic performance and safety with His-BPT. AMP-BPT might not preferentially reflect changes asthmatic symptoms. © 2015 John Wiley & Sons Ltd.

  8. Methacholine and adenosine 5'-monophosphate (AMP) responsiveness, and the presence and degree of atopy in children with asthma.

    Science.gov (United States)

    Suh, Dong I; Lee, Ju K; Kim, Chang K; Koh, Young Y

    2011-02-01

    The relationship between atopy and bronchial hyperresponsiveness (BHR), both key features of asthma, remains to be clarified. BHR is commonly evaluated by bronchial challenges using direct and indirect stimuli. The aim of this study was to investigate the degree of BHR to methacholine (direct stimulus) and adenosine 5'-monophosphate (AMP) (indirect stimulus) according to the presence and degree of atopy in children with asthma. We performed a retrospective analysis of data from 120 children presenting with a diagnosis of asthma. These children were characterized by skin-prick tests (SPTs), spirometry and bronchial challenges with methacholine and AMP. Atopy was defined by at least one positive reaction to SPTs, and its degree was measured using serum total IgE levels, number of positive SPTs and atopic scores (sum of graded wheal size). A provocative concentration causing a 20% decline in FEV(1) (PC(20) ) was determined for each challenge. Patients with atopy(n=94) had a significantly lower AMP PC(20) than non-atopic patients (n=26), whereas methacholine PC(20) was not different between the two groups. Among the patients with atopy, there was no association between methacholine PC(20) and any atopy parameter. In contrast, a significant association was found between AMP PC(20) and the degree of atopy reflected in serum total IgE, number of positive SPTs and atopic scores (anova trend test, p=0.002, 0.001, 0.003, respectively). AMP responsiveness was associated with the presence and degree of atopy, whereas such a relationship was not observed for methacholine responsiveness. These findings suggest that atopic status may be better reflected by bronchial responsiveness assessed by AMP than by methacholine. © 2011 John Wiley & Sons A/S.

  9. Relationships of methacholine and adenosine 5'-monophosphate (AMP) responsiveness to the postbronchodilator FEV₁/FVC ratio in children with asthma.

    Science.gov (United States)

    Suh, Dong In; Choi, Sun Hee; Lee, Ju Kyung; Kim, Jin-Tack; Koh, Young Yull

    2011-05-01

    Airway remodeling has been assumed to cause bronchial hyperresponsiveness (BHR). A low postbronchodilator FEV₁/FVC ratio has been suggested to be a functional surrogate marker of airway remodeling in asthma. BHR is commonly assessed by bronchial challenges using direct or indirect stimuli. The aim of this study was to compare BHR to methacholine and adenosine 5'-monophosphate (AMP) with regard to their relationship with a marker of airway remodeling in children with asthma. Methacholine and AMP challenge tests were performed in 129 children with asthma, aged 12 years, and a provocative concentration causing a 20% fall in FEV₁ (PC₂₀) was calculated for each challenge. All subjects also underwent pre- and postbronchodilator spirometry. A postbronchodilator FEV₁/FVC ratio below the lower limits of normal was used as a marker of airway remodeling. A low postbronchodilator FEV₁/FVC ratio was found in 17 subjects (13.2%). These subjects had a significantly lower methacholine PC₂₀ (geometric mean: 0.63 mg/mL, range of 1 SD: 0.17-2.29) than those (n = 112) with a normal postbronchodilator FEV₁/FVC ratio (2.42 mg/mL, 0.57-10.32, p = .000), whereas AMP PC₂₀ was similar between the two groups (22.1 mg/mL, 3.9-125.9 vs. 27.7 mg/mL, 4.2-183.5, p = .231). In the whole group of subjects, methacholine PC₂₀, but not AMP PC₂₀, correlated significantly with the postbronchodilator FEV₁/FVC ratio (r = 0.340, p = .000, and r = 0.056, p = .526, respectively). Our results provide evidence, though indirect, that BHR to methacholine is related to airway remodeling in children with asthma and suggest that BHR to methacholine may be a better marker of airway remodeling than BHR to AMP.

  10. Effects of exogenous inosine monophosphate on growth performance, flavor compounds, enzyme activity, and gene expression of muscle tissues in chicken.

    Science.gov (United States)

    Yan, Junshu; Liu, Peifeng; Xu, Liangmei; Huan, Hailin; Zhou, Weiren; Xu, Xiaoming; Shi, Zhendan

    2018-04-01

    The goal of this experiment was to examine effects of diets supplemented with exogenous inosine monophosphate (IMP) on the growth performance, flavor compounds, enzyme activity and gene expression of chicken. A total of 1,500 healthy, 1-day-old male 3-yellow chickens were used for a 52-d experimental period. Individuals were randomly divided into 5 groups (group I, II, III, IV, V) with 6 replicates per group, and fed a basal diet supplemented with 0.0, 0.05, 0.1, 0.2, and 0.3% IMP, respectively. There was no significant response to the increasing dietary IMP level in average daily feed intake (ADFI), average daily gain (ADG), and feed:gain ratio (F/G) (P ≥ 0.05). IMP content of the breast and thigh muscle showed an exponential and linear response to the increasing dietary IMP level (P exogenous IMP was fed. There were significant effects of IMP level in diet on free amino acids (FAA) (exponential, linear and quadratic effect, P exogenous IMP was fed. Dietary IMP supplementation had a quadratic effect on 5΄-NT and the alkaline phosphatase (ALP) enzyme activity in the breast muscle (P exogenous IMP group had the highest (AMPD1) gene expression of the breast muscle and ATIC gene expression of the thigh muscle. These results indicate that dietary IMP did not affect the growth performance of chicken, the diet with 0.2 to 0.3% exogenous IMP is optimal to improve the meat flavor quality in chicken.

  11. Ginsenoside Compound K suppresses the hepatic gluconeogenesis via activating adenosine-5'monophosphate kinase: A study in vitro and in vivo.

    Science.gov (United States)

    Wei, Shengnan; Li, Wei; Yu, Yang; Yao, Fan; A, Lixiang; Lan, Xiaoxin; Guan, Fengying; Zhang, Ming; Chen, Li

    2015-10-15

    Compound K (CK) is a final intestinal metabolite of protopanaxadiol-type ginsenoside. We have reported that CK presented anti-diabetic effect via diminishing the expressions of hepatic gluconeogenesis key enzyme. Here, we further explore the possible mechanism of CK on suppression hepatic gluconeogenesis via activation of adenosine-5'monophosphate kinase (AMPK) on type 2 diabetes mice in vivo and in HepG2 cells. Type 2 diabetes mice model was developed by high fat diet combined with STZ injection. 30mg/kg/d CK was orally administrated for 4weeks, the fasting blood glucose level and 2h OGTT were conducted, and the protein expression of AMPK, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), Phosphoenolpyruvate carboxykinase (PEPCK) and Glucose-6-phosphatase (G6Pase) were examined. The mechanism of Compound K on hepatic gluconeogenesis was further explored in HepG2 hepatocytes. Glucose production, the protein expression of AMPK, PEPCK, G6pase and PGC-1α, hepatic nuclear factor 4α (HNF-4α) and forkhead transcription factor O1 (FOXO1) were determined after Compound K treatment at the presence of AMPK inhibitor Compound C. We observed that CK inhibited the expression of PEPCK and G6Pase in the liver and in HepG2 hepatocytes. Meanwhile, CK treatment remarkably increased the activation of AMPK, while decreasing the expressions of PGC-1α, HNF-4α and FOXO1. However, AMPK inhibitor Compound C could reverse these effects of CK on gluconeogenesis in part. The results indicated that the effect of CK on suppression hepatic gluconeogenesis might be via the activation the AMPK activity. Copyright © 2015. Published by Elsevier Inc.

  12. Alteration of sodium, potassium-adenosine triphosphatase activity in rabbit ciliary processes by cyclic adenosine monophosphate-dependent protein kinase

    International Nuclear Information System (INIS)

    Delamere, N.A.; Socci, R.R.; King, K.L.

    1990-01-01

    The response of sodium, potassium-adenosine triphosphatase (Na,K-ATPase) to cyclic adenosine monophosphate (cAMP)-dependent protein kinase was examined in membranes obtained from rabbit iris-ciliary body. In the presence of the protein kinase together with 10(-5) M cAMP, Na,K-ATPase activity was reduced. No change in Na,K-ATPase activity was detected in response to the protein kinase without added cAMP. Likewise cAMP alone did not alter Na,K-ATPase activity. Reduction of Na,K-ATPase activity was also observed in the presence of the cAMP-dependent protein kinase catalytic subunit. The response of the enzyme to the kinase catalytic subunit was also examined in membranes obtained from rabbit ciliary processes. In the presence of 8 micrograms/ml of the catalytic subunit, ciliary process Na,K-ATPase activity was reduced by more than 50%. To examine whether other ATPases were suppressed by the protein kinase, calcium-stimulated ATPase activity was examined; its activity was stimulated by the catalytic subunit. To test whether the response of the ciliary process Na,K-ATPase is unique, experiments were also performed using membrane preparations from rabbit lens epithelium or rabbit kidney; the catalytic subunit significantly reduced the activity of Na,K-ATPase from the kidney but not the lens. These Na,K-ATPase studies suggest that in the iris-ciliary body, cAMP may alter sodium pump activity. In parallel 86Rb uptake studies, we observed that ouabain-inhibitable potassium uptake by intact pieces of iris-ciliary body was reduced by exogenous dibutryl cAMP or by forskolin

  13. Myricetin is a novel inhibitor of human inosine 5′-monophosphate dehydrogenase with anti-leukemia activity

    International Nuclear Information System (INIS)

    Pan, Huiling; Hu, Qian; Wang, Jingyuan; Liu, Zehui; Wu, Dang; Lu, Weiqiang; Huang, Jin

    2016-01-01

    Human inosine 5′-monophosphate dehydrogenase (hIMPDH) is a rate-limiting enzyme in the de novo biosynthetic pathway of purine nucleotides, playing crucial roles in cellular proliferation, differentiation, and transformation. Dysregulation of hIMPDH expression and activity have been found in a variety of human cancers including leukemia. In this study, we found that myricetin, a naturally occurring phytochemical existed in berries, wine and tea, was a novel inhibitor of human type 1 and type 2 IMPDH (hIMPDH1/2) with IC_5_0 values of 6.98 ± 0.22 μM and 4.10 ± 0.14 μM, respectively. Enzyme kinetic analysis using Lineweaver-Burk plot revealed that myricetin is a mix-type inhibitor for hIMPDH1/2. Differential scanning fluorimetry and molecular docking simulation data demonstrate that myricetin is capable of binding with hIMPDH1/2. Myricetin treatment exerts potent anti-proliferative and pro-apoptotic effects on K562 human leukemia cells in a dose-dependent manner. Importantly, cytotoxicity of myricetin on K562 cells were markedly attenuated by exogenous addition of guanosine, a salvage pathway of maintaining intracellular pool of guanine nucleotides. Taking together, these results indicate that natural product myricetin exhibits potent anti-leukemia activity by interfering with purine nucleotides biosynthetic pathway through the suppression of hIMPDH1/2 catalytic activity. - Highlights: • Myricetin, a common dietary flavonoid, is a novel inhibitor of hIMPDH1/2. • Myricetin directly binds with hIMPDH1/2 and induces cell cycle arrest and apoptosis of leukemia cells. • The cytotoxicity of myricetin on K562 cells is markedly attenuated by exogenous addition of guanosine.

  14. Erythrocyte metabolism in hyperthyroidism: a microcalorimetric study on changes in the Embden-Meyerhof and the hexose monophosphate pathways.

    Science.gov (United States)

    Monti, M; Hedner, P; Ikomi-Kumm, J; Valdemarsson, S

    1987-05-01

    Erythrocyte metabolism was studied in vitro by microcalorimetry in 10 hyperthyroid subjects before and after treatment. By inhibiting the enzyme enolase in the Embden-Meyerhof pathway with sodium fluoride (NaF) we have recorded the anaerobic and aerobic contributions in erythrocyte thermogenesis. The decrease in heat production rate in samples with NaF corresponds to the anaerobic contribution, whereas the values from samples with NaF reflect aerobic processes. Before treatment, total heat production rate was 120 +/- 2 mW/l erythrocytes which was higher than the post-treatment value of 99 +/- 2 (P less than 0.001) as well as the value for 14 euthyroid subjects, 108 +/- 2 mW/l (P less than 0.001). The NaF inhibitable rate was 73 +/- 2 before and 63 +/- 1 mW/l after therapy (P less than 0.01). These values correspond to 61 +/- 1 and 64 +/- 1% (n.s.) of the total heat production rate, and were similar to that of 61 +/- 2% for the controls. Heat production rates in the presence of NaF were 47 +/- 1 before and 36 +/- 1 mW/l after therapy (P less than 0.001), representing 39 +/- 1 and 36 +/- 1% of total values, respectively. The present results show that overall metabolism is increased in erythrocytes from hyperthyroid subjects before treatment and returns to normal after normalization of the thyroid function. Moreover, by using microcalorimetry we found that the metabolic activity along the Embden-Meyerhof anaerobic pathway as well as along the hexose monophosphate aerobic pathway in erythrocytes is stimulated by thyroid hormones.

  15. Myricetin is a novel inhibitor of human inosine 5′-monophosphate dehydrogenase with anti-leukemia activity

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Huiling; Hu, Qian; Wang, Jingyuan; Liu, Zehui; Wu, Dang [Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237 (China); Lu, Weiqiang, E-mail: wqlu@bio.ecnu.edu.cn [Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241 (China); Huang, Jin, E-mail: huangjin@ecust.edu.cn [Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237 (China)

    2016-09-02

    Human inosine 5′-monophosphate dehydrogenase (hIMPDH) is a rate-limiting enzyme in the de novo biosynthetic pathway of purine nucleotides, playing crucial roles in cellular proliferation, differentiation, and transformation. Dysregulation of hIMPDH expression and activity have been found in a variety of human cancers including leukemia. In this study, we found that myricetin, a naturally occurring phytochemical existed in berries, wine and tea, was a novel inhibitor of human type 1 and type 2 IMPDH (hIMPDH1/2) with IC{sub 50} values of 6.98 ± 0.22 μM and 4.10 ± 0.14 μM, respectively. Enzyme kinetic analysis using Lineweaver-Burk plot revealed that myricetin is a mix-type inhibitor for hIMPDH1/2. Differential scanning fluorimetry and molecular docking simulation data demonstrate that myricetin is capable of binding with hIMPDH1/2. Myricetin treatment exerts potent anti-proliferative and pro-apoptotic effects on K562 human leukemia cells in a dose-dependent manner. Importantly, cytotoxicity of myricetin on K562 cells were markedly attenuated by exogenous addition of guanosine, a salvage pathway of maintaining intracellular pool of guanine nucleotides. Taking together, these results indicate that natural product myricetin exhibits potent anti-leukemia activity by interfering with purine nucleotides biosynthetic pathway through the suppression of hIMPDH1/2 catalytic activity. - Highlights: • Myricetin, a common dietary flavonoid, is a novel inhibitor of hIMPDH1/2. • Myricetin directly binds with hIMPDH1/2 and induces cell cycle arrest and apoptosis of leukemia cells. • The cytotoxicity of myricetin on K562 cells is markedly attenuated by exogenous addition of guanosine.

  16. ATP signals

    DEFF Research Database (Denmark)

    Novak, Ivana

    2016-01-01

    The Department of Biology at the University of Copenhagen explains the function of ATP signalling in the pancreas......The Department of Biology at the University of Copenhagen explains the function of ATP signalling in the pancreas...

  17. Hypergravity signal transduction in HeLa cells with concomitant phosphorylation of proteins immunoprecipitated with anti-microtubule-associated protein antibodies

    Science.gov (United States)

    Kumei, Yasuhiro; Whitson, Peggy A.; Sato, Atsushige; Cintron, Nitza M.

    1991-01-01

    It is shown that hypergravity (35g) stimulates the production of inositol 1,4,5-trisphosphate (IP3) and decreases adenosine 3-prime,5-prime-cyclic monophosphate (cAMP) levels in HeLa cells. It is proposed that IP3 and cAMP may act as second messengers in hypergravity signal transduction. Phosphorylation of microtubule-associated proteins in both the detergent-soluble and -insoluble fractions suggests that cytoskeletal structures may be influenced by gravity.

  18. Nitric oxide-soluble guanylyl cyclase-cyclic GMP signaling in the striatum: New targets for the treatment of Parkinson's disease?

    Directory of Open Access Journals (Sweden)

    Anthony R West

    2011-06-01

    Full Text Available Striatal nitric oxide (NO-producing interneurons play an important role in the regulation of corticostriatal synaptic transmission and motor behavior. Striatal NO synthesis is driven by concurrent activation of NMDA and dopamine (DA D1 receptors. NO diffuses into the dendrites of medium-sized spiny neurons (MSNs which contain high levels of NO receptors called soluble guanylyl cyclases (sGC. NO-mediated activation of sGC leads to the synthesis of the second messenger cGMP. In the intact striatum, transient elevations in intracellular cGMP primarily act to increase neuronal excitability and to facilitate glutamatergic corticostriatal transmission. NO-cGMP signaling also functionally opposes the inhibitory effects of DA D2 receptor activation on corticostriatal transmission. Not surprisingly, abnormal striatal NO-sGC-cGMP signaling becomes apparent following striatal DA depletion, an alteration thought to contribute to pathophysiological changes observed in basal ganglia circuits in Parkinson’s disease (PD. Here, we discuss recent developments in the field which have shed light on the role of NO-sGC-cGMP signaling pathways in basal ganglia dysfunction and motor symptoms associated with PD and L-DOPA-induced dyskinesias.

  19. Characterization of radiation-induced products of thymidine 3'-monophosphate and thymidylyl (3'→5') thymidine by high-performance liquid chromatography and laser-desorption fourier-transform mass spectrometry

    International Nuclear Information System (INIS)

    Yoshida, H.; Hettich, R.L.

    1994-01-01

    High-performance liquid chromatography (HPLC) and laser-desorption Fourier-transform mass spectrometry (LD FTMS) have been applied for direct measurements of radiation-induced products of nucleic acid constituents containing thymidine. Laser desorption FTMS could be used for the direct detection (neither hydrolyzed nor derivatized) of X-ray-induced decomposition products of aqueous thymidine monophosphate. After these initial experiments, a variety of hydrogenated and hydroxylated thymine standards were acquired and examined by FTMS to assist in the identification of unknown radiation-induced decomposition products of thymine-containing nucleotides and dinucleotides. To extend these studies to dinucleotides, the radiation-induced products generated by the gamma radiolysis of thymidylyl (3'→5') thymidine (TpT) were isolated by reverse-phase HPLC and identified by LD FTMS. Thymine and thymidine 3'-monophosphate were observed as the major products in this case. Several of the minor products of the HPLC profile were pooled in a single fraction and characterized simultaneously by LD FTMS. The resulting mass spectra indicated the presence of hydroxy-5,6-dihydothymidine monophosphate, 5,6-dihydrothymidine monophosphate and thymidine monophosphate, thymine glycol, hydroxy-5,6-dihydrothymine, 5-hydroxy-methyl-uracil and 5,6-dihydrothymine. The combination of HPLC purification and LD FTMS structural characterization provides a useful tool for the direct measurement of radiation-induced products of nucleotides and dinucleotides. 28 refs., 6 figs., 2 tabs

  20. Nitric Oxide in Astrocyte-Neuron Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Li, Nianzhen [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Astrocytes, a subtype of glial cell, have recently been shown to exhibit Ca2+ elevations in response to neurotransmitters. A Ca2+ elevation can propagate to adjacent astrocytes as a Ca2+ wave, which allows an astrocyte to communicate with its neighbors. Additionally, glutamate can be released from astrocytes via a Ca2+-dependent mechanism, thus modulating neuronal activity and synaptic transmission. In this dissertation, the author investigated the roles of another endogenous signal, nitric oxide (NO), in astrocyte-neuron signaling. First the author tested if NO is generated during astrocytic Ca2+ signaling by imaging NO in purified murine cortical astrocyte cultures. Physiological concentrations of a natural messenger, ATP, caused a Ca2+-dependent NO production. To test the roles of NO in astrocytic Ca2+ signaling, the author applied NO to astrocyte cultures via addition of a NO donor, S-nitrosol-N-acetylpenicillamine (SNAP). NO induced an influx of external Ca2+, possibly through store-operated Ca2+ channels. The NO-induced Ca2+ signaling is cGMP-independent since 8-Br-cGMP, an agonistic analog of cGMP, did not induce a detectable Ca2+ change. The consequence of this NO-induced Ca2+ influx was assessed by simultaneously monitoring of cytosolic and internal store Ca2+ using fluorescent Ca2+ indicators x-rhod-1 and mag-fluo-4. Blockage of NO signaling with the NO scavenger PTIO significantly reduced the refilling percentage of internal stores following ATP-induced Ca2+ release, suggesting that NO modulates internal store refilling. Furthermore, locally photo-release of NO to a single astrocyte led to a Ca2+ elevation in the stimulated astrocyte and a subsequent Ca2+ wave to neighbors. Finally, the author tested the role of NO inglutamate-mediated astrocyte-neuron signaling by

  1. Behavior of the monophosphate tungsten bronzes (PO2)4(WO3)2m (m = 7 and 8) in the course of electrochemical lithium insertion

    International Nuclear Information System (INIS)

    Martinez-de la Cruz, A.; Longoria Rodriguez, F.E.; Gonzalez, Lucy T.; Torres-Martinez, Leticia M.

    2007-01-01

    The electrochemical lithium insertion process has been studied in the family of monophosphate tungsten bronzes (PO 2 ) 4 (WO 3 ) 2m , where m = 7 and 8. Structural changes in the pristine oxides were followed as lithium insertion proceeded. Through potentiostatic intermittent technique the different processes which take place in the cathode during the discharge of the cell were analyzed. The nature of the bronzes Li x (PO 2 ) 4 (WO 3 ) 2m formed was determined by in situ X-ray diffraction experiments. These results have allowed establishing a correlation with the reversible/irreversible processes detected during the electrochemical lithium insertion

  2. Effects of adenosine monophosphate on induction of therapeutic hypothermia and neuronal damage after cardiopulmonary resuscitation in rats.

    Science.gov (United States)

    Knapp, Jürgen; Schneider, Andreas; Nees, Corinna; Bruckner, Thomas; Böttiger, Bernd W; Popp, Erik

    2014-09-01

    Animal studies and pathophysiological considerations suggest that therapeutic hypothermia after cardiopulmonary resuscitation is the more effective the earlier it is induced. Therefore this study is sought to examine whether pharmacological facilitated hypothermia by administration of 5'-adenosine monophosphate (AMP) is neuroprotective in a rat model of cardiac arrest (CA) and resuscitation. Sixty-one rats were subjected to CA. After 6 min of ventricular fibrillation advanced cardiac life support was started. After successful return of spontaneous circulation (ROSC, n=40), animals were randomized either to placebo group (n=14) or AMP group (800 mg/kg body weight, n=14). Animals were kept at an ambient temperature of 18°C for 12 h after ROSC and core body temperature was measured using a telemetry temperature probe. Neuronal damage was analyzed by counting Nissl-positive (i.e. viable) neurons and TUNEL-positive (i.e. apoptotic) cells in coronal brain sections 7 days after ROSC. Functional status evaluated on days 1, 3 and 7 after ROSC by a tape removal test. Time until core body temperature dropped to <34.0°C was 31 min [28; 45] in AMP-treated animals and 125 min [90; 180] in the control group (p=0.003). Survival until 7 days after ROSC was comparable in both groups. Also number of Nissl-positive cells (AMP: 1 [1; 7] vs. placebo: 2 [1; 3] per 100 pixel; p=0.66) and TUNEL-positive cells (AMP: 56 [44; 72] vs. placebo: 53 [41; 67] per 100 pixel; p=0.70) did not differ. Neither did AMP affect functional neurological outcome up to 7 days after ROSC. Mean arterial pressure 20 min after ROSC was 49 [45; 55] mmHg in the AMP group in comparison to 91 [83; 95] mmHg in the control group (p<0.001). Although application of AMP reduced the time to reach a core body temperature of <34°C neither survival was improved nor neuronal damage attenuated. Reason for this is probably induction of marked hypotension as an adverse reaction to AMP treatment. Copyright © 2014 Elsevier

  3. An Examination of the Role of L-Glutamate and Inosine 5'-Monophosphate in Hedonic Taste-Guided Behavior by Mice Lacking the T1R1 + T1R3 Receptor.

    Science.gov (United States)

    Blonde, Ginger D; Spector, Alan C

    2017-06-01

    The heterodimeric T1R1 + T1R3 receptor is considered critical for normal signaling of L-glutamate and 5'-ribonucleotides in the oral cavity. However, some taste-guided responsiveness remains in mice lacking one subunit of the receptor, suggesting that other receptors are sufficient to support some behaviors. Here, mice lacking both receptor subunits (KO) and wild-type (WT, both n = 13) mice were tested in a battery of behavioral tests. Mice were trained and tested in gustometers with a concentration series of Maltrin-580, a maltodextrin, in a brief-access test (10-s trials) as a positive control. Similar tests followed with monosodium glutamate (MSG) with and without the ribonucleotide inosine 5'-monophosphate (IMP), but always in the presence of the epithelial sodium channel blocker amiloride (A). Brief-access tests were repeated following short-term (30-min) and long-term (48-h) exposures to MSG + A + IMP and were also conducted with sodium gluconate replacing MSG. Finally, progressive ratio tests were conducted with Maltrin-580 or MSG + A + IMP, to assess appetitive behavior while minimizing satiation. Overall, MSG generated little concentration-dependent responding in either food-restricted WT or KO mice, even in combination with IMP. However, KO mice licked less to the amino acid stimuli, a measure of consummatory behavior in the brief-access tests. In contrast, both groups initiated a similar number of trials and had a similar breakpoint in the progressive ratio task, both measures of appetitive (approach) behavior. Collectively, these results suggest that while the T1R1 + T1R3 receptor is necessary for consummatory responding to MSG (+IMP), other receptors are sufficient to maintain appetitive responding to this "umami" stimulus complex in food-restricted mice. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Signaling aggression.

    Science.gov (United States)

    van Staaden, Moira J; Searcy, William A; Hanlon, Roger T

    2011-01-01

    From psychological and sociological standpoints, aggression is regarded as intentional behavior aimed at inflicting pain and manifested by hostility and attacking behaviors. In contrast, biologists define aggression as behavior associated with attack or escalation toward attack, omitting any stipulation about intentions and goals. Certain animal signals are strongly associated with escalation toward attack and have the same function as physical attack in intimidating opponents and winning contests, and ethologists therefore consider them an integral part of aggressive behavior. Aggressive signals have been molded by evolution to make them ever more effective in mediating interactions between the contestants. Early theoretical analyses of aggressive signaling suggested that signals could never be honest about fighting ability or aggressive intentions because weak individuals would exaggerate such signals whenever they were effective in influencing the behavior of opponents. More recent game theory models, however, demonstrate that given the right costs and constraints, aggressive signals are both reliable about strength and intentions and effective in influencing contest outcomes. Here, we review the role of signaling in lieu of physical violence, considering threat displays from an ethological perspective as an adaptive outcome of evolutionary selection pressures. Fighting prowess is conveyed by performance signals whose production is constrained by physical ability and thus limited to just some individuals, whereas aggressive intent is encoded in strategic signals that all signalers are able to produce. We illustrate recent advances in the study of aggressive signaling with case studies of charismatic taxa that employ a range of sensory modalities, viz. visual and chemical signaling in cephalopod behavior, and indicators of aggressive intent in the territorial calls of songbirds. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. The phytosulfokine (PSK) receptor is capable of guanylate cyclase activity and enabling cyclic GMP-dependent signaling in plants

    KAUST Repository

    Kwezi, Lusisizwe; Ruzvidzo, Oziniel; Wheeler, Janet I.; Govender, Kershini; Iacuone, Sylvana; Thompson, Philip E.; Gehring, Christoph A; Irving, Helen R.

    2011-01-01

    Phytosulfokines (PSKs) are sulfated pentapeptides that stimulate plant growth and differentiation mediated by the PSK receptor (PSKR1), which is a leucine-rich repeat receptor-like kinase. We identified a putative guanylate cyclase (GC) catalytic center in PSKR1 that is embedded within the kinase domain and hypothesized that the GC works in conjunction with the kinase in downstream PSK signaling. We expressed the recombinant complete kinase (cytoplasmic) domain of AtPSKR1 and show that it has serine/threonine kinase activity using the Ser/Thr peptide 1 as a substrate with an approximate Km of 7.5 μM and Vmax of 1800 nmol min-1 mg-1 of protein. This same recombinant protein also has GC activity in vitro that is dependent on the presence of either Mg2+ or Mn2+. Overexpression of the full-length AtPSKR1 receptor in Arabidopsis leaf protoplasts raised the endogenous basal cGMP levels over 20-fold, indicating that the receptor has GC activity in vivo. In addition, PSK-α itself, but not the non-sulfated backbone, induces rapid increases in cGMP levels in protoplasts. Together these results indicate that the PSKR1 contains dual GC and kinase catalytic activities that operate in vivo and that this receptor constitutes a novel class of enzymes with overlapping catalytic domains. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. The phytosulfokine (PSK) receptor is capable of guanylate cyclase activity and enabling cyclic GMP-dependent signaling in plants

    KAUST Repository

    Kwezi, Lusisizwe

    2011-04-19

    Phytosulfokines (PSKs) are sulfated pentapeptides that stimulate plant growth and differentiation mediated by the PSK receptor (PSKR1), which is a leucine-rich repeat receptor-like kinase. We identified a putative guanylate cyclase (GC) catalytic center in PSKR1 that is embedded within the kinase domain and hypothesized that the GC works in conjunction with the kinase in downstream PSK signaling. We expressed the recombinant complete kinase (cytoplasmic) domain of AtPSKR1 and show that it has serine/threonine kinase activity using the Ser/Thr peptide 1 as a substrate with an approximate Km of 7.5 μM and Vmax of 1800 nmol min-1 mg-1 of protein. This same recombinant protein also has GC activity in vitro that is dependent on the presence of either Mg2+ or Mn2+. Overexpression of the full-length AtPSKR1 receptor in Arabidopsis leaf protoplasts raised the endogenous basal cGMP levels over 20-fold, indicating that the receptor has GC activity in vivo. In addition, PSK-α itself, but not the non-sulfated backbone, induces rapid increases in cGMP levels in protoplasts. Together these results indicate that the PSKR1 contains dual GC and kinase catalytic activities that operate in vivo and that this receptor constitutes a novel class of enzymes with overlapping catalytic domains. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. The arabidopsis wall associated kinase-like 10 gene encodes a functional guanylyl cyclase and is co-expressed with pathogen defense related genes

    KAUST Repository

    Meier, Stuart; Ruzvidzo, Oziniel; Morse, Monique; Donaldson, Lara; Kwezi, Lusisizwe; Gehring, Christoph A

    2010-01-01

    Background: Second messengers have a key role in linking environmental stimuli to physiological responses. One such messenger, guanosine 3?,5?-cyclic monophosphate (cGMP), has long been known to be an essential signaling molecule in many different physiological processes in higher plants, including biotic stress responses. To date, however, the guanylyl cyclase (GC) enzymes that catalyze the formation of cGMP from GTP have largely remained elusive in higher plants. Principal Findings: We have identified an Arabidopsis receptor type wall associated kinase-like molecule (AtWAKL10) as a candidate GC and provide experimental evidence to show that the intracellular domain of AtWAKL10431-700 can generate cGMP in vitro. Further, we also demonstrate that the molecule has kinase activity indicating that AtWAKL10 is a twin-domain catalytic protein. A co-expression and stimulus-specific expression analysis revealed that AtWAKL10 is consistently coexpressed with well characterized pathogen defense related genes and along with these genes is induced early and sharply in response to a range of pathogens and their elicitors. Conclusions: We demonstrate that AtWAKL10 is a twin-domain, kinase-GC signaling molecule that may function in biotic stress responses that are critically dependent on the second messenger cGMP. © 2010 Meier et al.

  8. The arabidopsis wall associated kinase-like 10 gene encodes a functional guanylyl cyclase and is co-expressed with pathogen defense related genes

    KAUST Repository

    Meier, Stuart

    2010-01-26

    Background: Second messengers have a key role in linking environmental stimuli to physiological responses. One such messenger, guanosine 3?,5?-cyclic monophosphate (cGMP), has long been known to be an essential signaling molecule in many different physiological processes in higher plants, including biotic stress responses. To date, however, the guanylyl cyclase (GC) enzymes that catalyze the formation of cGMP from GTP have largely remained elusive in higher plants. Principal Findings: We have identified an Arabidopsis receptor type wall associated kinase-like molecule (AtWAKL10) as a candidate GC and provide experimental evidence to show that the intracellular domain of AtWAKL10431-700 can generate cGMP in vitro. Further, we also demonstrate that the molecule has kinase activity indicating that AtWAKL10 is a twin-domain catalytic protein. A co-expression and stimulus-specific expression analysis revealed that AtWAKL10 is consistently coexpressed with well characterized pathogen defense related genes and along with these genes is induced early and sharply in response to a range of pathogens and their elicitors. Conclusions: We demonstrate that AtWAKL10 is a twin-domain, kinase-GC signaling molecule that may function in biotic stress responses that are critically dependent on the second messenger cGMP. © 2010 Meier et al.

  9. Molecular characterization of adenosine 5'-monophosphate deaminase--the key enzyme responsible for the umami taste of nori (Porphyra yezoensis Ueda, Rhodophyta).

    Science.gov (United States)

    Minami, Seiko; Sato, Minoru; Shiraiwa, Yoshihiro; Iwamoto, Koji

    2011-12-01

    The enzyme adenosine 5'-monophosphate deaminase (AMPD, EC 3.5.4.6) catalyzes the conversion of adenosine 5'-monophosphate to inosine 5'-mononucleotide (IMP). IMP is generally known as the compound responsible for the umami taste of the edible red alga Porphyra yezoensis Ueda that is known in Japan as nori. Therefore, we suspect that AMPD plays a key role in providing a favorable nori taste. In this study, we undertake the molecular characterization of nori-derived AMPD. The nori AMPD protein has a molecular mass of 55 kDa as estimated from both gel filtration and sodium dodecyl sulfate polyacrylamide gel electrophoresis. The calculated molecular mass from the amino acid sequence deduced from cDNA is 57.1 kDa. The isoelectric point is 5.71. The coding region of AMPD consists of 1,566 bp encoding 522 amino acids and possesses a transmembrane domain and two N-glycosylation sites. The sequence identity of nori AMPD in human and yeast AMPDs was found to be less than 50% and 20% in DNA and amino acid sequences, respectively. Proline in the conserved motif of [SA]-[LIVM]-[NGS]-[STA]-D-D-P was found to be converted to glutamate. These results indicate that nori AMPD is a novel type of AMPD.

  10. OXIDACIÓN DE p -NITROFENOL USANDO TiO 2 -ADENOSINA MONOFOSFATO I OXIDATION OF p -NITROPHENOL USING TiO 2 -ADENOSIN MONOPHOSPHATE

    Directory of Open Access Journals (Sweden)

    Carlos F. Rivas

    2018-04-01

    Full Text Available The surface of TiO2 was modified with the nucleotides adenosine 3’-monophosphate (AMP’3 and Adenosine 5’-monophosphate (AMP’5. The adsorption of nucleotides was adjusted to Langmuir ́s adsorption model, determining that the optimal condition for TiO 2 modification was at neutral pH. UV-Visible Diffuse Reflectance and IR Attenuated Total Reflectance spectra show that the chemisorption of nucleotides take placed on TiO 2 anatase. The new catalysts (TiO 2 -nucleotide improved the photodegradation of p -nitrophenol in a wide range of pH as compared with the titanium dioxide precursor. Most photoactivity was generated by using the new photocatalytic in the degradation of p -nitrophenol at pH = 6, obtaining high values for the pseudo first order kinetic constant (0.0254 min -1 and 0.0244 min -1 for TiO 2 -AMP’3 and TiO 2 -AMP’5, respectively. For all pH, the trend obtained for the photodegradation was: TiO 2 -AMP ́3 @ TiO 2 -AMP’5 > TiO 2 . Langmuir-Hinshelwood kinetics shows that the contribution of the surface reac tion rate governs the oxidation of the contaminant.

  11. Signal detection

    International Nuclear Information System (INIS)

    Tholomier, M.

    1985-01-01

    In a scanning electron microscope, whatever is the measured signal, the same set is found: incident beam, sample, signal detection, signal amplification. The resulting signal is used to control the spot luminosity with the observer cathodoscope. This is synchronized with the beam scanning on the sample; on the cathodoscope, the image in secondary electrons, backscattered electrons,... of the sample surface is reconstituted. The best compromise must be found between a register time low enough to remove eventual variations (under the incident beam) of the nature of the observed phenomenon, and a good spatial resolution of the image and a signal-to-noise ratio high enough. The noise is one of the basic limitations of the scanning electron microscope performance. The whose measurement line must be optimized to reduce it [fr

  12. Bronchial responsiveness to adenosine-5 '-monophosphate and methacholine as predictors for nasal symptoms due to newly introduced allergens. A follow-up study among laboratory animal workers and bakery apprentices

    NARCIS (Netherlands)

    de Meer, G; Postma, DS; Heederik, D

    Background In asthma patients, bronchial hyper-responsiveness (BHR) to adenosine-5'-monophosphate (AMP) reflects bronchial inflammation more closely than BHR to methacholine. In this follow-up study we studied bronchial responsiveness to both stimuli as predictors of new-onset airway symptoms.

  13. SIMULTANEOUS ANALYSIS OF AZIDOTHYMIDINE AND ITS MONOPHOSPHATE, DIPHOSPHATE AND TRIPHOSPHATE DERIVATIVES IN BIOLOGICAL-FLUIDS, TISSUE AND CULTURED-CELLS BY A RAPID HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD

    NARCIS (Netherlands)

    MOLEMA, G; JANSEN, RW; Visser, Jan; MEIJER, DKF

    1992-01-01

    A rapid high-performance liquid chromatographic (HPLC) method for the simultaneous analysis of the antiviral drug azidothymidine (AZT), AZT monophosphate, AZT diphosphate and AZT triphosphate, with ultraviolet detection in the nanomolar range, is described. Determination of these compounds in vitro

  14. Evolution of coherent collective modes through consecutive charge-density-wave transitions in the (PO2)4(WO3)12 monophosphate tungsten bronze

    Science.gov (United States)

    Stojchevska, L.; Borovšak, M.; Foury-Leylekian, P.; Pouget, J.-P.; Mertelj, T.; Mihailovic, D.

    2017-07-01

    All-optical femtosecond relaxation dynamics in a single crystal of monophosphate tungsten bronze (PO2)4(WO3)2m with alternate stacking m =6 of WO3 layers was studied through the three consequent charge-density-wave (CDW) transitions. Several transient coherent collective modes associated with the different CDW transitions were observed and analyzed in the framework of the time-dependent Ginzburg-Landau theory. Remarkably, the interference of the modes leads to an apparent rectification effect in the transient reflectivity response. A saturation of the coherent-mode amplitudes with increasing pump fluence well below the CDWs destruction threshold fluence indicates a decoupling of the electronic and lattice parts of the order parameter on the femtosecond timescale.

  15. The influence of dibutyryl adenosine cyclic monophosphate on cell proliferation in the epithelium of the jejunal crypts, the colonic crypts and in colonic carcinomata of rat.

    Science.gov (United States)

    Tutton, P J; Barkla, D H

    1980-01-01

    1. Cell proliferation in the jejunal crypts, the colonic crypts and in dimethylhydrazine (DMH)-induced adenocarcinomata of rat colon was measured using a stathmokinetic technique. 2. Dibutryl cyclic adneosine monophosphate (dibutyryl cAMP) was found to inhibit cell proliferation in colonic crypts and in colonic adenocarcinomata. 3. Dibutryl cAMP at very high doses was found to inhibit jejunal crypt cell proliferation but at lower doses was found to accelerate jejunal crypt cell proliferation. 4. Neither bilateral adrenalectomy nor chemical sympathectomy was found to abolish the ability of dibutryl cAMP to stimulate jejunal crypt cell proliferation. 5. The present results are difficult to interpret in terms of known hormonal influences on cell proliferation in the tissues examined and of established actions, of these hormones on cyclic nucleotide metabolism in other tissues.

  16. Characterization of free radicals in γ-irradiated polycrystalline uridine 5'-monophosphate: a study combining ESR, spin-trapping and HPLC

    International Nuclear Information System (INIS)

    Hiraoka, W.; Kuwabara, M.; Sato, F.

    1991-01-01

    Free radicals generated in γ-irradiated polycrystalline uridine 5'-monophosphate (5'-UMP) were studied by ESR, spin-trapping and high-performance liquid chromatography (HPLC). Although HPLC ultimately gave four spin-adducts, one component that was originally present disappeared during HPLC. Spin adducts due to two types of C6 radials were identified. One of these was thought to be formed by electron addition and subsequent protonation at the C6 position, and the other was presumed to be produced by electron addition and subsequent protonation at the O 4 position. The spin adducts derived from the C5 and C5' radicals were also identified. The spin adduct that disappeared during HPLC was thought to correspond to the C4'-centred radical. Computer simulation of ESR spectra was carried out to estimate the hyperfine splitting constants. (author)

  17. Studies of short-lived radicals in the. gamma. -irradiated aqueous solution of uridine-5'-monophosphate by the spin-trapping method and the liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Kominami, S [Hiroshima Univ. (Japan); Rokushika, S; Hatano, H

    1976-12-01

    An aerated aqueous solution of uridine-5'-monophosphate was ..gamma..-irradiated with 2-methyl-2-nitrosopropane as a spin-trapping reagent. Liquid chromatography was applied to separate the stable nitroxide radicals in the irradiated solution. The radicals were detected by U.V. and e.s.r. spectrometry. The e.s.r. detection showed four peaks in the chromatogram. The orcinol method for detection of the residual sugar moieties was applied before and after reduction of the base to determine the existence of the 5,6-double bond for the molecules in each fraction. From the combined results of the e.s.r. and orcinol methods, the short-lived radicals which were trapped by 2-methyl-2-nitrosopropane were identified as radicals of N-1 and C-6 positions of the base moiety and t-butyl radicals which was the radiolytic product of the trapping reagent.

  18. Modulation of growth performance, immunological responses and disease resistance of juvenile Nile tilapia (Oreochromis niloticus (Linnaeus, 1758 by supplementing dietary inosine monophosphate

    Directory of Open Access Journals (Sweden)

    Md. Abdul Kader

    2018-05-01

    Full Text Available This study was investigated to examine supplemental effects of dietary inosine monophosphate (IMP on growth performance, feed utilization, biochemical, hematological and immunological parameters of juvenile Nile tilapia Oreochromis niloticus. Disease resistance to experimental infection with Streptococcus agalactiae was also assessed. A semi-purified basal diet was supplemented with 0 (IMP0, Control, 1 (IMP1, 2 (IMP2, 4 (IMP4 and 8 (IMP8 g purified IMP kg−1 diet to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (0.59 g for 60 days. The results indicated that supplementation of IMP significantly (P  0.05. Among whole body proximate composition and somatic parameters, condition factor was significantly influenced by dietary supplementation of IMP. A wide variation in hematological parameters were observed and dietary supplementation increased the hematocrit content (P  0.05. Total serum protein (TSP, lysozyme activity (LA, superoxide dismutase activity (SOD and bactericidal activity (BA tended to increase with the supplementation of dietary IMP. TSP and SOD were significantly improved with ≥4 g kg−1 supplementation, while LA with 8 g kg−1 and BA with ≥1 g kg−1 supplementations. IMP supplemented groups showed higher (P > 0.05 cumulative survival compared to that of supplementation free control group. IMP supplemented diet groups also showed significantly higher BA in the post challenge test. Based on the overall performances, the results of the current study indicated that the inclusion of IMP in Nile tilapia diet can improve growth performance, feed utilization, haematological and immunological parameters; and disease resistance of juvenile Nile tilapia. Keywords: Nucleotides, Inosine monophosphate, Growth, Immunity, Disease resistance, Nile tilapia, Streptococcus agalactiae

  19. Adenosine 3',5'-cyclic monophosphate (cAMP)-dependent phosphoregulation of mitochondrial complex I is inhibited by nucleoside reverse transcriptase inhibitors

    International Nuclear Information System (INIS)

    Lund, Kaleb C.; Wallace, Kendall B.

    2008-01-01

    Nucleoside analog reverse transcriptase inhibitors (NRTIs) are known to directly inhibit mitochondrial complex I activity as well as various mitochondrial kinases. Recent observations that complex I activity and superoxide production are modulated through cAMP-dependent phosphorylation suggests a mechanism through which NRTIs may affect mitochondrial respiration via kinase-dependent protein phosphorylation. In the current study, we examine the potential for NRTIs to inhibit the cAMP-dependent phosphorylation of complex I and the associated NADH:CoQ oxidoreductase activities and rates of superoxide production using HepG2 cells. Phosphoprotein staining of immunocaptured complex I revealed that 3'-azido-3'-deoxythymidine (AZT; 10 and 50 μM), AZT monophosphate (150 μM), and 2',3'-dideoxycytidine (ddC; 1 μM) prevented the phosphorylation of the NDUFB11 subunit of complex I. This was associated with a decrease in complex I activity with AZT and AZT monophosphate only. In the presence of succinate, superoxide production was increased with 2',3'-dideoxyinosine (ddI; 10 μM) and ddC (1 μM). In the presence of succinate + cAMP, AZT showed an inverse dose-dependent effect on superoxide production. None of the NRTIs examined inhibit PKA activity suggesting that the observed effects are due to a direct interaction with complex I. These data demonstrate a direct effect of NRTIs on cAMP-dependent regulation of mitochondrial bioenergetics independent of DNA polymerase-γ activity; in the case of AZT, these observations may provide a mechanism for the observed long-term toxicity with this drug

  20. Roles of NO signaling in long-term memory formation in visual learning in an insect.

    Directory of Open Access Journals (Sweden)

    Yukihisa Matsumoto

    Full Text Available Many insects exhibit excellent capability of visual learning, but the molecular and neural mechanisms are poorly understood. This is in contrast to accumulation of information on molecular and neural mechanisms of olfactory learning in insects. In olfactory learning in insects, it has been shown that cyclic AMP (cAMP signaling critically participates in the formation of protein synthesis-dependent long-term memory (LTM and, in some insects, nitric oxide (NO-cyclic GMP (cGMP signaling also plays roles in LTM formation. In this study, we examined the possible contribution of NO-cGMP signaling and cAMP signaling to LTM formation in visual pattern learning in crickets. Crickets that had been subjected to 8-trial conditioning to associate a visual pattern with water reward exhibited memory retention 1 day after conditioning, whereas those subjected to 4-trial conditioning exhibited 30-min memory retention but not 1-day retention. Injection of cycloheximide, a protein synthesis inhibitor, into the hemolymph prior to 8-trial conditioning blocked formation of 1-day memory, whereas it had no effect on 30-min memory formation, indicating that 1-day memory can be characterized as protein synthesis-dependent long-term memory (LTM. Injection of an inhibitor of the enzyme producing an NO or cAMP prior to 8-trial visual conditioning blocked LTM formation, whereas it had no effect on 30-min memory formation. Moreover, injection of an NO donor, cGMP analogue or cAMP analogue prior to 4-trial conditioning induced LTM. Induction of LTM by an NO donor was blocked by DDA, an inhibitor of adenylyl cyclase, an enzyme producing cAMP, but LTM induction by a cAMP analogue was not impaired by L-NAME, an inhibitor of NO synthase. The results indicate that cAMP signaling is downstream of NO signaling for visual LTM formation. We conclude that visual learning and olfactory learning share common biochemical cascades for LTM formation.

  1. Stimulation of cyclic GMP efflux in human melanocytes by hypergravity generated by centrifugal acceleration

    NARCIS (Netherlands)

    Ivanova, Krassimira; Zadeh, Nahid Hamidi; Block, Ingrid; Das, Pranab K.; Gerzer, Rupert

    2004-01-01

    Gravity alteration (micro- and hypergravity) is known to influence cell functions. As guanosine 3',5'-cyclic monophosphate (cGMP) plays an important role in human melanocyte functions and different guanylyl cyclase isoforms are responsible for cGMP synthesis in human non-metastatic and metastatic

  2. Signal Processing

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Signal processing techniques, extensively used nowadays to maximize the performance of audio and video equipment, have been a key part in the design of hardware and software for high energy physics detectors since pioneering applications in the UA1 experiment at CERN in 1979

  3. New Insights into the Cyclic Di-adenosine Monophosphate (c-di-AMP) Degradation Pathway and the Requirement of the Cyclic Dinucleotide for Acid Stress Resistance in Staphylococcus aureus.

    Science.gov (United States)

    Bowman, Lisa; Zeden, Merve S; Schuster, Christopher F; Kaever, Volkhard; Gründling, Angelika

    2016-12-30

    Nucleotide signaling networks are key to facilitate alterations in gene expression, protein function, and enzyme activity in response to diverse stimuli. Cyclic di-adenosine monophosphate (c-di-AMP) is an important secondary messenger molecule produced by the human pathogen Staphylococcus aureus and is involved in regulating a number of physiological processes including potassium transport. S. aureus must ensure tight control over its cellular levels as both high levels of the dinucleotide and its absence result in a number of detrimental phenotypes. Here we show that in addition to the membrane-bound Asp-His-His and Asp-His-His-associated (DHH/DHHA1) domain-containing phosphodiesterase (PDE) GdpP, S. aureus produces a second cytoplasmic DHH/DHHA1 PDE Pde2. Although capable of hydrolyzing c-di-AMP, Pde2 preferentially converts linear 5'-phosphadenylyl-adenosine (pApA) to AMP. Using a pde2 mutant strain, pApA was detected for the first time in S. aureus, leading us to speculate that this dinucleotide may have a regulatory role under certain conditions. Moreover, pApA is involved in a feedback inhibition loop that limits GdpP-dependent c-di-AMP hydrolysis. Another protein linked to the regulation of c-di-AMP levels in bacteria is the predicted regulator protein YbbR. Here, it is shown that a ybbR mutant S. aureus strain has increased acid sensitivity that can be bypassed by the acquisition of mutations in a number of genes, including the gene coding for the diadenylate cyclase DacA. We further show that c-di-AMP levels are slightly elevated in the ybbR suppressor strains tested as compared with the wild-type strain. With this, we not only identified a new role for YbbR in acid stress resistance in S. aureus but also provide further insight into how c-di-AMP levels impact acid tolerance in this organism. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Hindbrain A2 noradrenergic neuron adenosine 5'-monophosphate-activated protein kinase activation, upstream kinase/phosphorylase protein expression, and receptivity to hormone and fuel reporters of short-term food deprivation are regulated by estradiol.

    Science.gov (United States)

    Briski, Karen P; Alenazi, Fahaad S H; Shakya, Manita; Sylvester, Paul W

    2017-07-01

    Estradiol (E) mitigates acute and postacute adverse effects of 12 hr-food deprivation (FD) on energy balance. Hindbrain 5'-monophosphate-activated protein kinase (AMPK) regulates hyperphagic and hypothalamic metabolic neuropeptide and norepinephrine responses to FD in an E-dependent manner. Energy-state information from AMPK-expressing hindbrain A2 noradrenergic neurons shapes neural responses to metabolic imbalance. Here we investigate the hypothesis that FD causes divergent changes in A2 AMPK activity in E- vs. oil (O)-implanted ovariectomized female rats, alongside dissimilar adjustments in circulating metabolic fuel (glucose, free fatty acids [FFA]) and energy deficit-sensitive hormone (corticosterone, glucagon, leptin) levels. FD decreased blood glucose in oil (O)- but not E-implanted ovariectomized female rats and elevated and reduced glucagon levels in O and E, respectively. FD decreased circulating leptin in O and E, but increased corticosterone and FFA concentrations in E only. Western blot analysis of laser-microdissected A2 neurons showed that glucocorticoid receptor type II and very-long-chain acyl-CoA synthetase 3 protein profiles were amplified in FD/E vs. FD/O. A2 total AMPK protein was elevated without change in activity in FD/O, whereas FD/E exhibited increased AMPK activation along with decreased upstream phosphatase expression. The catecholamine biosynthetic enzyme dopamine-β-hydroxylase (DβH) was increased in FD/O but not FD/E A2 cells. The data show discordance between A2 AMPK activation and glycemic responses to FD; sensor activity was refractory to glucose decrements in FD/O but augmented in FD/E despite stabilized glucose and elevated FFA levels. E-dependent amplification of AMPK activity may reflect adaptive conversion to fatty acid oxidation and/or glucocorticoid stimulation. FD augmentation of A2 DβH protein profiles in FD/O but not FD/E animals suggests that FD may correspondingly regulate NE synthesis vs. metabolism/release in the

  5. Novel Radioligands for Cyclic Nucleotide Phosphodiesterase Imaging with Positron Emission Tomography: An Update on Developments Since 2012

    Directory of Open Access Journals (Sweden)

    Susann Schröder

    2016-05-01

    Full Text Available Cyclic nucleotide phosphodiesterases (PDEs are a class of intracellular enzymes that inactivate the secondary messenger molecules, cyclic adenosine monophosphate (cAMP and cyclic guanosine monophosphate (cGMP. Thus, PDEs regulate the signaling cascades mediated by these cyclic nucleotides and affect fundamental intracellular processes. Pharmacological inhibition of PDE activity is a promising strategy for treatment of several diseases. However, the role of the different PDEs in related pathologies is not completely clarified yet. PDE-specific radioligands enable non-invasive visualization and quantification of these enzymes by positron emission tomography (PET in vivo and provide an important translational tool for elucidation of the relationship between altered expression of PDEs and pathophysiological effects as well as (pre-clinical evaluation of novel PDE inhibitors developed as therapeutics. Herein we present an overview of novel PDE radioligands for PET published since 2012.

  6. Integrin Signalling

    OpenAIRE

    Schelfaut, Roselien

    2005-01-01

    Integrins are receptors presented on most cells. By binding ligand they can generate signalling pathways inside the cell. Those pathways are a linkage to proteins in the cytosol. It is known that tumor cells can survive and proliferate in the absence of a solid support while normal cells need to be bound to ligand. To understand why tumour cells act that way, we first have to know how ligand-binding to integrins affect the cell. This research field includes studies on activation of proteins b...

  7. Silymarin Suppresses Cellular Inflammation By Inducing Reparative Stress Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Lovelace, Erica S.; Wagoner, Jessica; MacDonald, James; Bammler, Theo; Bruckner, Jacob; Brownell, Jessica; Beyer, Richard; Zink, Erika M.; Kim, Young-Mo; Kyle, Jennifer E.; Webb-Robertson, Bobbie-Jo M.; Waters, Katrina M.; Metz, Thomas O.; Farin, Federico; Oberlies, Nicholas H.; Polyak, Steve

    2015-08-28

    Silymarin (SM), a natural product, is touted as a liver protectant and preventer of both chronic inflammation and diseases. To define how SM elicits these effects at a systems level, we performed transcriptional profiling, metabolomics, and signaling studies in human liver and T cell lines. Multiple pathways associated with cellular stress and metabolism were modulated by SM treatment within 0.5 to four hours: activation of Activating Transcription Factor 4 (ATF-4) and adenosine monophosphate protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) signaling, the latter being associated with induction of DNA-damage-inducible transcript 4 (DDIT4). Metabolomics analyses revealed suppression of glycolytic, TCA cycle, and amino acid metabolism by SM treatment. Antiinflammatory effects arose with prolonged (i.e. 24 hours) SM exposure, with suppression of multiple proinflammatory mRNAs and nuclear factor kappa B (NF-κB) and forkhead box O (FOXO) signaling. Studies with murine knock out cells revealed that SM inhibition of both mTOR and NF-κB was partially AMPK dependent, while SM inhibition of the mTOR pathway in part required DDIT4. Thus, SM activates stress and repair responses that culminate in an anti-inflammatory phenotype. Other natural products induced similar stress responses, which correlated with their ability to suppress inflammation. Therefore, natural products like SM may be useful as tools to define how metabolic, stress, and repair pathways regulate cellular inflammation.

  8. [Physiopathology of cAMP/PKA signaling in neurons].

    Science.gov (United States)

    Castro, Liliana; Yapo, Cedric; Vincent, Pierre

    2016-01-01

    Cyclic adenosine monophosphate (cAMP) and the cyclic-AMP dependent protein kinase (PKA) regulate a plethora of cellular functions in virtually all eukaryotic cells. In neurons, the cAMP/PKA signaling cascade controls a number of biological properties such as axonal growth, synaptic transmission, regulation of excitability or long term changes in the nucleus. Genetically-encoded optical biosensors for cAMP or PKA considerably improved our understanding of these processes by providing a real-time measurement in living neurons. In this review, we describe the recent progresses made in the creation of biosensors for cAMP or PKA activity. These biosensors revealed profound differences in the amplitude of the cAMP signal evoked by neuromodulators between various neuronal preparations. These responses can be resolved at the level of individual neurons, also revealing differences related to the neuronal type. At the subcellular level, biosensors reported different signal dynamics in domains like dendrites, cell body, nucleus and axon. Combining this imaging approach with pharmacology or genetical models points at phosphodiesterases and phosphatases as critical regulatory proteins. Biosensor imaging will certainly help understand the mechanism of action of current drugs as well as help in devising novel therapeutic strategies for neuropsychiatric diseases. © Société de Biologie, 2017.

  9. Structure and dynamics of the ApA, ApC, CpA and CpC RNA dinucleoside monophosphates resolved with NMR scalar spin-spin couplings

    Czech Academy of Sciences Publication Activity Database

    Vokáčová, Zuzana; Schneider, Bohdan; Buděšínský, Miloš; Rosenberg, Ivan; Šponer, Jiří; Sychrovský, Vladimír

    2009-01-01

    Roč. 16, 1a (2009), b52-b52 ISSN 1211-5894. [Meeting of the Czechoslovak and Slovak Biologists /7./. 12.03.2009-14.03.2009, Nové Hrady] R&D Projects: GA AV ČR IAA400550701 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50040507 Keywords : NMR * dinucleoside monophosphate Subject RIV: CF - Physical ; Theoretical Chemistry

  10. Discovery of N-[2-[2-[[3-methoxy-4-(5-oxazolyl)phenyl]amino]-5-oxazolyl]phenyl]-N-methyl-4- morpholineacetamide as a novel and potent inhibitor of inosine monophosphate dehydrogenase with excellent in vivo activity.

    Science.gov (United States)

    Dhar, T G Murali; Shen, Zhongqi; Guo, Junqing; Liu, Chunjian; Watterson, Scott H; Gu, Henry H; Pitts, William J; Fleener, Catherine A; Rouleau, Katherine A; Sherbina, N Z; McIntyre, Kim W; Shuster, David J; Witmer, Mark R; Tredup, Jeffrey A; Chen, Bang-Chi; Zhao, Rulin; Bednarz, Mark S; Cheney, Daniel L; MacMaster, John F; Miller, Laura M; Berry, Karen K; Harper, Timothy W; Barrish, Joel C; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2002-05-23

    Inosine monophosphate dehydrogenase (IMPDH) is a key enzyme that is involved in the de novo synthesis of purine nucleotides. Novel 2-aminooxazoles were synthesized and tested for inhibition of IMPDH catalytic activity. Multiple analogues based on this chemotype were found to inhibit IMPDH with low nanomolar potency. One of the analogues (compound 23) showed excellent in vivo activity in the inhibition of antibody production in mice and in the adjuvant induced arthritis model in rats.

  11. Contribution of altered signal transduction associated to glutamate receptors in brain to the neurological alterations of hepatic encephalopathy

    Institute of Scientific and Technical Information of China (English)

    Vicente Felipo

    2006-01-01

    Patients with liver disease may present hepatic encephalopathy (HE), a complex neuropsychiatric syndrome covering a wide range of neurological alterations,including cognitive and motor disturbances. HE reduces the quality of life of the patients and is associated with poor prognosis. In the worse cases HE may lead to coma or death.The mechanisms leading to HE which are not well known are being studied using animal models. The neurological alterations in HE are a consequence of impaired cerebral function mainly due to alterations in neurotransmission. We review here some studies indicating that alterations in neurotransmission associated to different types of glutamate receptors are responsible for some of the cognitive and motor alterations present in HE.These studies show that the function of the signal transduction pathway glutamate-nitric oxide-cGMP associated to the NMDA type of glutamate receptors is impaired in brain in vivo in HE animal models as well as in brain of patients died of HE. Activation of NMDA receptors in brain activates this pathway and increases cGMP. In animal models of HE this increase in cGMP induced by activation of NMDA receptors is reduced,which is responsible for the impairment in learning ability in these animal models. Increasing cGMP by pharmacological means restores learning ability in rats with HE and may be a new therapeutic approach to improve cognitive function in patients with HE.However, it is necessary to previously assess the possible secondary effects.Patients with HE may present psychomotor slowing,hypokinesia and bradykinesia. Animal models of HE also show hypolocomotion. It has been shown in rats with HE that hypolocomotion is due to excessive activation of metabotropic glutamate receptors (mGluRs) in substantia nigra pars reticulata. Blocking mGluR1 in this brain area normalizes motor activity in the rats, suggesting that a similar treatment for patients with HE could be useful to treat psychomotor slowing and

  12. Transmission of innate immune signaling by packaging of cGAMP in viral particles.

    Science.gov (United States)

    Gentili, Matteo; Kowal, Joanna; Tkach, Mercedes; Satoh, Takeshi; Lahaye, Xavier; Conrad, Cécile; Boyron, Marilyn; Lombard, Bérangère; Durand, Sylvère; Kroemer, Guido; Loew, Damarys; Dalod, Marc; Théry, Clotilde; Manel, Nicolas

    2015-09-11

    Infected cells detect viruses through a variety of receptors that initiate cell-intrinsic innate defense responses. Cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS) is a cytosolic sensor for many DNA viruses and HIV-1. In response to cytosolic viral DNA, cGAS synthesizes the second messenger 2'3'-cyclic GMP-AMP (cGAMP), which activates antiviral signaling pathways. We show that in cells producing virus, cGAS-synthesized cGAMP can be packaged in viral particles and extracellular vesicles. Viral particles efficiently delivered cGAMP to target cells. cGAMP transfer by viral particles to dendritic cells activated innate immunity and antiviral defenses. Finally, we show that cell-free murine cytomegalovirus and Modified Vaccinia Ankara virus contained cGAMP. Thus, transfer of cGAMP by viruses may represent a defense mechanism to propagate immune responses to uninfected target cells. Copyright © 2015, American Association for the Advancement of Science.

  13. Application and optimization of the tenderization of pig Longissimus dorsi muscle by adenosine 5'-monophosphate (AMP) using the response surface methodology.

    Science.gov (United States)

    Deng, Shaoying; Wang, Daoying; Zhang, Muhan; Geng, Zhiming; Sun, Chong; Bian, Huan; Xu, Weimin; Zhu, Yongzhi; Liu, Fang; Wu, Haihong

    2016-03-01

    Based on single factor experiments, NaCl concentration, adenosine 5'-monophosphate (AMP) concentration and temperature were selected as independent variables for a three-level Box-Behnken experimental design, and the shear force and cooking loss were response values for regression analysis. According to the statistical models, it showed that all independent variables had significant effects on shear force and cooking loss, and optimal values were at the NaCl concentration of 4.15%, AMP concentration of 22.27 mmol/L and temperature of 16.70°C, which was determined with three-dimensional response surface diagrams and contour plots. Under this condition, the observed shear force and cooking loss were 0.625 kg and 8.07%, respectively, exhibiting a good agreement with their predicted values, showing the good applicability and feasibility of response surface methodology (RSM) for improving pork tenderness. Compared with control pig muscles, AMP combined with NaCl treatment demonstrated significant effects on improvement of meat tenderness and reduction of cooking loss. Therefore, AMP could be regarded as an effective tenderization agent for pork. © 2015 Japanese Society of Animal Science.

  14. AS160 associates with the Na+,K+-ATPase and mediates the adenosine monophosphate-stimulated protein kinase-dependent regulation of sodium pump surface expression.

    Science.gov (United States)

    Alves, Daiane S; Farr, Glen A; Seo-Mayer, Patricia; Caplan, Michael J

    2010-12-01

    The Na(+),K(+)-ATPase is the major active transport protein found in the plasma membranes of most epithelial cell types. The regulation of Na(+),K(+)-ATPase activity involves a variety of mechanisms, including regulated endocytosis and recycling. Our efforts to identify novel Na(+),K(+)-ATPase binding partners revealed a direct association between the Na(+),K(+)-ATPase and AS160, a Rab-GTPase-activating protein. In COS cells, coexpression of AS160 and Na(+),K(+)-ATPase led to the intracellular retention of the sodium pump. We find that AS160 interacts with the large cytoplasmic NP domain of the α-subunit of the Na(+),K(+)-ATPase. Inhibition of the activity of the adenosine monophosphate-stimulated protein kinase (AMPK) in Madin-Darby canine kidney cells through treatment with Compound C induces Na(+),K(+)-ATPase endocytosis. This effect of Compound C is prevented through the short hairpin RNA-mediated knockdown of AS160, demonstrating that AMPK and AS160 participate in a common pathway to modulate the cell surface expression of the Na(+),K(+)-ATPase.

  15. Solubility of disodium cytidine 5′-monophosphate in different binary mixtures from 288.15 K to 313.15 K

    International Nuclear Information System (INIS)

    Yu, Jin; Ma, Tianle; Li, An; Chen, Xiaochun; Chen, Yong; Xie, Jingjing; Wu, Jinglan; Ying, Hanjie

    2013-01-01

    Highlights: • Solubility of 5′-CMPNa 2 in different systems was measured the first time. • Experimental data were correlated by CNIBS/Redlich–Kister model and Apelblat model. • Good agreement has been observed between the calculated and the experimental data. • Enthalpy and entropy were calculated by the van’t Hoff equation and Gibbs equation. - Abstract: The solubility of disodium cytidine 5′-monophosphate (5′-CMPNa 2 ) in methanol + water and ethanol + water binary mixtures was measured experimentally at the temperatures ranging from 288.15 to 313.15 K. The results showed that the solubility of 5′-CMPNa 2 increased with the increasing of temperature and the mole fraction of water in different binary mixtures. The (CNIBS)/Redlich–Kister model and the semi-empirical Apelblat model were applied for the prediction of the experimental data. Both models could give satisfactory simulation results. In addition, the thermodynamic properties of the dissolution process such as Gibbs energy, enthalpy, and entropy were calculated using the van’t Hoff equation and the Gibbs equation. The results indicated that the dissolution process was endothermic

  16. Effects of octacosanol extracted from rice bran on blood hormone levels and gene expressions of glucose transporter protein-4 and adenosine monophosphate protein kinase in weaning piglets

    Directory of Open Access Journals (Sweden)

    Lei Long

    2015-12-01

    Full Text Available The object of this study was to explore the regulatory mechanism of octacosanol to the body of animals and the effects of octacosanol on blood hormone levels and gene expressions of glucose transporter protein (GLUT-4 and adenosine monophosphate protein kinase (AMPK in liver and muscle tissue of weaning piglets. A total of 105 crossbred piglets ([Yorkshire × Landrace] × Duroc with an initial BW of 5.70 ± 1.41 kg (21 d of age were used in a 6-wk trial to evaluate the effects of octacosanol and tiamulin supplementation on contents of triiodothyronine (T3, thyroxine (T4, growth hormone (GH, glucagon (GU and adrenaline (AD in blood and gene expressions of GLUT-4 and AMPK in liver and muscle. Piglets were randomly distributed into 3 dietary treatments on the basis of BW and sex. Each treatment had 7 replicate pens with 5 piglets per pen. Treatments were as followed: control group, tiamulin group and octacosanol group. The results showed that compared with control group and tiamulin group, octacosanol greatly promoted the secretion of T3, GH, GU and AD (P  0.05. Results of the present study has confirmed that octacosanol affects energy metabolism of body by regulating secretion of blood hormones and related gene expression in tissue of weaning piglets, which can reduce stress response and has an impact on performance.

  17. Adenosine monophosphate is elevated in the bronchoalveolar lavage fluid of mice with acute respiratory toxicity induced by nanoparticles with high surface hydrophobicity.

    Science.gov (United States)

    Dailey, Lea Ann; Hernández-Prieto, Raquel; Casas-Ferreira, Ana Maria; Jones, Marie-Christine; Riffo-Vasquez, Yanira; Rodríguez-Gonzalo, Encarnación; Spina, Domenico; Jones, Stuart A; Smith, Norman W; Forbes, Ben; Page, Clive; Legido-Quigley, Cristina

    2015-02-01

    Inhaled nanomaterials present a challenge to traditional methods and understanding of respiratory toxicology. In this study, a non-targeted metabolomics approach was used to investigate relationships between nanoparticle hydrophobicity, inflammatory outcomes and the metabolic fingerprint in bronchoalveolar fluid. Measures of acute lung toxicity were assessed following single-dose intratracheal administration of nanoparticles with varying surface hydrophobicity (i.e. pegylated lipid nanocapsules, polyvinyl acetate nanoparticles and polystyrene beads; listed in order of increasing hydrophobicity). Broncho-alveolar lavage (BAL) fluid was collected from mice exposed to nanoparticles at a surface area dose of 220 cm(2) and metabolite fingerprints were acquired via ultra pressure liquid chromatography-mass spectrometry-based metabolomics. Particles with high surface hydrophobicity were pro-inflammatory. Multivariate analysis of the resultant small molecule fingerprints revealed clear discrimination between the vehicle control and polystyrene beads (p < 0.05), as well as between nanoparticles of different surface hydrophobicity (p < 0.0001). Further investigation of the metabolic fingerprints revealed that adenosine monophosphate (AMP) concentration in BAL correlated with neutrophilia (p < 0.01), CXCL1 levels (p < 0.05) and nanoparticle surface hydrophobicity (p < 0.001). Our results suggest that extracellular AMP is an intermediary metabolite involved in adenine nucleotide-regulated neutrophilic inflammation as well as tissue damage, and could potentially be used to monitor nanoparticle-induced responses in the lung following pulmonary administration.

  18. Formation of Mixed-Ligand Complexes of Pd2+ with Nucleoside 5'-Monophosphates and Some Metal-Ion-Binding Nucleoside Surrogates

    Directory of Open Access Journals (Sweden)

    Oleg Golubev

    2014-10-01

    Full Text Available Formation of mixed-ligand Pd2+ complexes between canonical nucleoside 5'-monophosphates and five metal-ion-binding nucleoside analogs has been studied by 1H-NMR spectroscopy to test the ability of these nucleoside surrogates to discriminate between unmodified nucleobases by Pd2+-mediated base pairing. The nucleoside analogs studied included 2,6-bis(3,5-dimethylpyrazol-1-yl-, 2,6-bis(1-methylhydrazinyl- and 6-(3,5-dimethylpyrazol-1-yl-substituted 9-(β-d-ribofuranosylpurines 1–3, and 2,4-bis(3,5-dimethylpyrazol-1-yl- and 2,4-bis(1-methylhydrazinyl-substituted 5-(β-d-ribofuranosyl-pyrimidines 4–5. Among these, the purine derivatives 1-3 bound Pd2+ much more tightly than the pyrimidine derivatives 4, 5 despite apparently similar structures of the potential coordination sites. Compounds 1 and 2 formed markedly stable mixed-ligand Pd2+ complexes with UMP and GMP, UMP binding favored by 1 and GMP by 2. With 3, formation of mixed-ligand complexes was retarded by binding of two molecules of 3 to Pd2+.

  19. Developmental Competence of Vitrified-Warmed Bovine Oocytes at the Germinal-Vesicle Stage is Improved by Cyclic Adenosine Monophosphate Modulators during In Vitro Maturation.

    Directory of Open Access Journals (Sweden)

    Kenji Ezoe

    Full Text Available Cryopreservation of mature oocytes and embryos has provided numerous benefits in reproductive medicine. Although successful cryopreservation of germinal-vesicle stage (GV oocytes holds promise for further advances in reproductive biology and clinical embryology fields, reports regarding cryopreservation of immature oocytes are limited. Oocyte survival and maturation rates have improved since vitrification is being performed at the GV stage, but the subsequent developmental competence of GV oocytes is still low. The purpose of this study was to evaluate the effects of supplementation of the maturation medium with cyclic adenosine monophosphate (cAMP modulators on the developmental competence of vitrified-warmed GV bovine oocytes. GV oocytes were vitrified-warmed and cultured to allow for oocyte maturation, and then parthenogenetically activated or fertilized in vitro. Our results indicate that addition of a cAMP modulator forskolin (FSK or 3-isobutyl-1-methylxanthine (IBMX to the maturation medium significantly improved the developmental competence of vitrified-warmed GV oocytes. We also demonstrated that vitrification of GV oocytes led to a decline in cAMP levels and maturation-promoting factor (MPF activity in the oocytes during the initial and final phases of maturation, respectively. Nevertheless, the addition of FSK or IBMX to the maturation medium significantly elevated cAMP levels and MPF activity during IVM. Taken together, our results suggest that the cryopreservation-associated meiotic and developmental abnormalities observed in GV oocytes may be ameliorated by an artificial increase in cAMP levels during maturation culture after warming.

  20. Host-guest chemistry of dendrimer-drug complexes. 4. An in-depth look into the binding/encapsulation of guanosine monophosphate by dendrimers.

    Science.gov (United States)

    Hu, Jingjing; Fang, Min; Cheng, Yiyun; Zhang, Jiahai; Wu, Qinglin; Xu, Tongwen

    2010-06-03

    In the present study, we investigated the host-guest chemistry of dendrimer/guanosine monophosphate (GMP) and present an in-depth look into the binding/encapsulation of GMP by dendrimers using NMR studies. (1)H NMR spectra showed a significant downfield shift of methylene protons in the outmost layer of the G5 dendrimer, indicating the formation of ion pairs between cationic amine groups of dendrimer and anionic phosphate groups of GMP. Chemical shift titration results showed that the binding constant between G5 dendrimer and GMP is 17,400 M(-1) and each G5 dendrimer has 107 binding sites. The binding of GMP to dendrimers prevents its aggregation in aqueous solutions and thereby enhances its stability. Nuclear Overhauser effect measurements indicated that a GMP binding and encapsulation balance occurs on the surface and in the interior of dendrimer. The binding/encapsulation transitions can be easily tailored by altering the surface and interior charge densities of the dendrimer. All these findings provide a new insight into the host-guest chemistry of dendrimer/guest complexes and may play important roles in the study of dendrimer/DNA aggregates by a "bottom-up" strategy.

  1. Solubility of disodium cytidine 5′-monophosphate in different binary mixtures from 288.15 K to 313.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jin [College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing (China); National Engineering Technique Research Center for Biotechnology, Nanjing (China); Ma, Tianle; Li, An [National Engineering Technique Research Center for Biotechnology, Nanjing (China); State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing (China); Chen, Xiaochun; Chen, Yong; Xie, Jingjing [College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing (China); National Engineering Technique Research Center for Biotechnology, Nanjing (China); Wu, Jinglan, E-mail: yinghanjie@njut.edu.cn [College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing (China); National Engineering Technique Research Center for Biotechnology, Nanjing (China); Ying, Hanjie [College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing (China); National Engineering Technique Research Center for Biotechnology, Nanjing (China); State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing (China)

    2013-08-10

    Highlights: • Solubility of 5′-CMPNa{sub 2} in different systems was measured the first time. • Experimental data were correlated by CNIBS/Redlich–Kister model and Apelblat model. • Good agreement has been observed between the calculated and the experimental data. • Enthalpy and entropy were calculated by the van’t Hoff equation and Gibbs equation. - Abstract: The solubility of disodium cytidine 5′-monophosphate (5′-CMPNa{sub 2}) in methanol + water and ethanol + water binary mixtures was measured experimentally at the temperatures ranging from 288.15 to 313.15 K. The results showed that the solubility of 5′-CMPNa{sub 2} increased with the increasing of temperature and the mole fraction of water in different binary mixtures. The (CNIBS)/Redlich–Kister model and the semi-empirical Apelblat model were applied for the prediction of the experimental data. Both models could give satisfactory simulation results. In addition, the thermodynamic properties of the dissolution process such as Gibbs energy, enthalpy, and entropy were calculated using the van’t Hoff equation and the Gibbs equation. The results indicated that the dissolution process was endothermic.

  2. Pharmacokinetics of IDX184, a liver-targeted oral prodrug of 2'-methylguanosine-5'-monophosphate, in the monkey and formulation optimization for human exposure.

    Science.gov (United States)

    Pan-Zhou, Xin-Ru; Mayes, Benjamin A; Rashidzadeh, Hassan; Gasparac, Rahela; Smith, Steven; Bhadresa, Sanjeev; Gupta, Kusum; Cohen, Marita Larsson; Bu, Charlie; Good, Steven S; Moussa, Adel; Rush, Roger

    2016-10-01

    IDX184 is a phosphoramidate prodrug of 2'-methylguanosine-5'-monophosphate, developed to treat patients infected with hepatitis C virus. A mass balance study of radiolabeled IDX184 and pharmacokinetic studies of IDX184 in portal vein-cannulated monkeys revealed relatively low IDX184 absorption but higher exposure of IDX184 in the portal vein than in the systemic circulation, indicating >90 % of the absorbed dose was subject to hepatic extraction. Systemic exposures to the main metabolite, 2'-methylguanosine (2'-MeG), were used as a surrogate for liver levels of the pharmacologically active entity 2'-MeG triphosphate, and accordingly, systemic levels of 2'-MeG in the monkey were used to optimize formulations for further clinical development of IDX184. Capsule formulations of IDX184 delivered acceptable levels of 2'-MeG in humans; however, the encapsulation process introduced low levels of the genotoxic impurity ethylene sulfide (ES), which necessitated formulation optimization. Animal pharmacokinetic data guided the development of a tablet with trace levels of ES and pharmacokinetic performance equal to that of the clinical capsule in the monkey. Under fed conditions in humans, the new tablet formulation showed similar exposure to the capsule used in prior clinical trials.

  3. Free radical formation in deoxyguanosine-5'-monophosphate γ-irradiated in frozen solution. A computer-assisted analysis of temperature-dependent ESR spectra

    International Nuclear Information System (INIS)

    Gregoli, S.; Olast, M.; Bertinchamps, A.

    1977-01-01

    Deoxyguanosine-5'-monophosphate (dGMP) was γ-irradiated at 77 K in frozen aqueous solution and then annealed in a stepwise fashion up to the melting point. During this process, the primary radicals formed in DGMP at 77 K are progressively converted into secondary radical species. This is observed as changes in the spectrum intensity and conformation. Computer-assisted analysis of these temperature-dependent spectra permitted us to identify the transient radical species involved and to draw up single-radical concentration kinetics vs temperature. The radiation chemical behavior of dGMP was found to be quite similar to that of dAMP, investigated previously. In both these purine derivatives, radical anions are converted into radicals of H-addition to C-8, and radical cations are converted into radicals of OH-addition to the same position. In dGMP, however, the cationic channel is only induced under certain experimental conditions (alkaline pH, presence of electron scavengers). At neutral pH, G + radicals are quite stable and finally become deactivated without being converted into secondary GOH radicals. Specific deuterium substitution at carbon C-8, and irradiation in H 2 O or in D 2 O, confirmed that both H + and OH - attachments do occur at C-8, and that both the H + and OH - groups come from the aqueous medium

  4. The regulatory role of the NO/cGMP signal transduction cascade during larval attachment and metamorphosis of the barnacle Balanus (=Amphibalanus) amphitrite

    KAUST Repository

    Zhang, Y.

    2012-08-01

    The barnacle Balanus amphitrite is among the most dominant fouling species on intertidal rocky shores in tropical and subtropical areas and is thus a target organism in antifouling research. After being released from adults, the swimming nauplius undertakes six molting cycles and then transforms into a cyprid. Using paired antennules, a competent cyprid actively explores and selects a suitable substratum for attachment and metamorphosis (collectively known as settlement). This selection process involves the reception of exogenous signals and subsequent endogenous signal transduction. To investigate the involvement of nitric oxide (NO) and cyclic GMP (cGMP) during larval settlement of B. amphitrite, we examined the effects of an NO donor and an NO scavenger, two nitric oxide synthase (NOS) inhibitors and a soluble guanylyl cyclase (sGC) inhibitor on settling cyprids. We found that the NO donor sodium nitroprusside (SNP) inhibited larval settlement in a dose-dependent manner. In contrast, both the NO scavenger carboxy-PTIO and the NOS inhibitors aminoguanidine hemisulfate (AGH) and S-methylisothiourea sulfate (SMIS) significantly accelerated larval settlement. Suppression of the downstream guanylyl cyclase (GC) activity using a GC-selective inhibitor ODQ could also significantly accelerate larval settlement. Interestingly, the settlement inhibition effects of SNP could be attenuated by ODQ at all concentrations tested. In the developmental expression profiling of NOS and sGC, the lowest expression of both genes was detected in the cyprid stage, a crucial stage for the larval decision to attach and metamorphose. In summary, we concluded that NO regulates larval settlement via mediating downstream cGMP signaling.

  5. The regulatory role of the NO/cGMP signal transduction cascade during larval attachment and metamorphosis of the barnacle Balanus (=Amphibalanus) amphitrite

    KAUST Repository

    Zhang, Y.; He, L.-S.; Zhang, G.; Xu, Y.; Lee, O.-O.; Matsumura, K.; Qian, P.-Y.

    2012-01-01

    The barnacle Balanus amphitrite is among the most dominant fouling species on intertidal rocky shores in tropical and subtropical areas and is thus a target organism in antifouling research. After being released from adults, the swimming nauplius undertakes six molting cycles and then transforms into a cyprid. Using paired antennules, a competent cyprid actively explores and selects a suitable substratum for attachment and metamorphosis (collectively known as settlement). This selection process involves the reception of exogenous signals and subsequent endogenous signal transduction. To investigate the involvement of nitric oxide (NO) and cyclic GMP (cGMP) during larval settlement of B. amphitrite, we examined the effects of an NO donor and an NO scavenger, two nitric oxide synthase (NOS) inhibitors and a soluble guanylyl cyclase (sGC) inhibitor on settling cyprids. We found that the NO donor sodium nitroprusside (SNP) inhibited larval settlement in a dose-dependent manner. In contrast, both the NO scavenger carboxy-PTIO and the NOS inhibitors aminoguanidine hemisulfate (AGH) and S-methylisothiourea sulfate (SMIS) significantly accelerated larval settlement. Suppression of the downstream guanylyl cyclase (GC) activity using a GC-selective inhibitor ODQ could also significantly accelerate larval settlement. Interestingly, the settlement inhibition effects of SNP could be attenuated by ODQ at all concentrations tested. In the developmental expression profiling of NOS and sGC, the lowest expression of both genes was detected in the cyprid stage, a crucial stage for the larval decision to attach and metamorphose. In summary, we concluded that NO regulates larval settlement via mediating downstream cGMP signaling.

  6. The necrotic signal induced by mycophenolic acid overcomes apoptosis-resistance in tumor cells.

    Directory of Open Access Journals (Sweden)

    Gwendaline Guidicelli

    Full Text Available BACKGROUND: The amount of inosine monophosphate dehydrogenase (IMPDH, a pivotal enzyme for the biosynthesis of the guanosine tri-phosphate (GTP, is frequently increased in tumor cells. The anti-viral agent ribavirin and the immunosuppressant mycophenolic acid (MPA are potent inhibitors of IMPDH. We recently showed that IMPDH inhibition led to a necrotic signal requiring the activation of Cdc42. METHODOLOGY/PRINCIPAL FINDINGS: Herein, we strengthened the essential role played by this small GTPase in the necrotic signal by silencing Cdc42 and by the ectopic expression of a constitutive active mutant of Cdc42. Since resistance to apoptosis is an essential step for the tumorigenesis process, we next examined the effect of the MPA-mediated necrotic signal on different tumor cells demonstrating various mechanisms of resistance to apoptosis (Bcl2-, HSP70-, Lyn-, BCR-ABL-overexpressing cells. All tested cells remained sensitive to MPA-mediated necrotic signal. Furthermore, inhibition of IMPDH activity in Chronic Lymphocytic Leukemia cells was significantly more efficient at eliminating malignant cells than apoptotic inducers. CONCLUSIONS/SIGNIFICANCE: These findings indicate that necrosis and apoptosis are split signals that share few if any common hub of signaling. In addition, the necrotic signaling pathway induced by depletion of the cellular amount of GTP/GDP would be of great interest to eliminate apoptotic-resistant tumor cells.

  7. The role of the Hedgehog signaling pathway in cancer: A comprehensive review

    Directory of Open Access Journals (Sweden)

    Ana Marija Skoda

    2018-02-01

    Full Text Available The Hedgehog (Hh signaling pathway was first identified in the common fruit fly. It is a highly conserved evolutionary pathway of signal transmission from the cell membrane to the nucleus. The Hh signaling pathway plays an important role in the embryonic development. It exerts its biological effects through a signaling cascade that culminates in a change of balance between activator and repressor forms of glioma-associated oncogene (Gli transcription factors. The components of the Hh signaling pathway involved in the signaling transfer to the Gli transcription factors include Hedgehog ligands (Sonic Hh [SHh], Indian Hh [IHh], and Desert Hh [DHh], Patched receptor (Ptch1, Ptch2, Smoothened receptor (Smo, Suppressor of fused homolog (Sufu, kinesin protein Kif7, protein kinase A (PKA, and cyclic adenosine monophosphate (cAMP. The activator form of Gli travels to the nucleus and stimulates the transcription of the target genes by binding to their promoters. The main target genes of the Hh signaling pathway are PTCH1, PTCH2, and GLI1. Deregulation of the Hh signaling pathway is associated with developmental anomalies and cancer, including Gorlin syndrome, and sporadic cancers, such as basal cell carcinoma, medulloblastoma, pancreatic, breast, colon, ovarian, and small-cell lung carcinomas. The aberrant activation of the Hh signaling pathway is caused by mutations in the related genes (ligand-independent signaling or by the excessive expression of the Hh signaling molecules (ligand-dependent signaling – autocrine or paracrine. Several Hh signaling pathway inhibitors, such as vismodegib and sonidegib, have been developed for cancer treatment. These drugs are regarded as promising cancer therapies, especially for patients with refractory/advanced cancers.

  8. Retinal Cyclic Nucleotide-Gated Channels: From Pathophysiology to Therapy

    Directory of Open Access Journals (Sweden)

    Stylianos Michalakis

    2018-03-01

    Full Text Available The first step in vision is the absorption of photons by the photopigments in cone and rod photoreceptors. After initial amplification within the phototransduction cascade the signal is translated into an electrical signal by the action of cyclic nucleotide-gated (CNG channels. CNG channels are ligand-gated ion channels that are activated by the binding of cyclic guanosine monophosphate (cGMP or cyclic adenosine monophosphate (cAMP. Retinal CNG channels transduce changes in intracellular concentrations of cGMP into changes of the membrane potential and the Ca2+ concentration. Structurally, the CNG channels belong to the superfamily of pore-loop cation channels and share a common gross structure with hyperpolarization-activated cyclic nucleotide-gated (HCN channels and voltage-gated potassium channels (KCN. In this review, we provide an overview on the molecular properties of CNG channels and describe their physiological role in the phototransduction pathways. We also discuss insights into the pathophysiological role of CNG channel proteins that have emerged from the analysis of CNG channel-deficient animal models and human CNG channelopathies. Finally, we summarize recent gene therapy activities and provide an outlook for future clinical application.

  9. The Popeye Domain Containing Genes and cAMP Signaling

    Directory of Open Access Journals (Sweden)

    Thomas Brand

    2014-05-01

    Full Text Available 3'-5'-cyclic adenosine monophosphate (cAMP is a second messenger, which plays an important role in the heart. It is generated in response to activation of G-protein-coupled receptors (GPCRs. Initially, it was thought that protein kinase A (PKA exclusively mediates cAMP-induced cellular responses such as an increase in cardiac contractility, relaxation, and heart rate. With the identification of the exchange factor directly activated by cAMP (EPAC and hyperpolarizing cyclic nucleotide-gated (HCN channels as cAMP effector proteins it became clear that a protein network is involved in cAMP signaling. The Popeye domain containing (Popdc genes encode yet another family of cAMP-binding proteins, which are prominently expressed in the heart. Loss-of-function mutations in mice are associated with cardiac arrhythmia and impaired skeletal muscle regeneration. Interestingly, the cardiac phenotype, which is present in both, Popdc1 and Popdc2 null mutants, is characterized by a stress-induced sinus bradycardia, suggesting that Popdc proteins participate in cAMP signaling in the sinuatrial node. The identification of the two-pore channel TREK-1 and Caveolin 3 as Popdc-interacting proteins represents a first step into understanding the mechanisms of heart rate modulation triggered by Popdc proteins.

  10. Bacterial Biofilm Control by Perturbation of Bacterial Signaling Processes

    Directory of Open Access Journals (Sweden)

    Tim Holm Jakobsen

    2017-09-01

    Full Text Available The development of effective strategies to combat biofilm infections by means of either mechanical or chemical approaches could dramatically change today’s treatment procedures for the benefit of thousands of patients. Remarkably, considering the increased focus on biofilms in general, there has still not been invented and/or developed any simple, efficient and reliable methods with which to “chemically” eradicate biofilm infections. This underlines the resilience of infective agents present as biofilms and it further emphasizes the insufficiency of today’s approaches used to combat chronic infections. A potential method for biofilm dismantling is chemical interception of regulatory processes that are specifically involved in the biofilm mode of life. In particular, bacterial cell to cell signaling called “Quorum Sensing” together with intracellular signaling by bis-(3′-5′-cyclic-dimeric guanosine monophosphate (cyclic-di-GMP have gained a lot of attention over the last two decades. More recently, regulatory processes governed by two component regulatory systems and small non-coding RNAs have been increasingly investigated. Here, we review novel findings and potentials of using small molecules to target and modulate these regulatory processes in the bacterium Pseudomonas aeruginosa to decrease its pathogenic potential.

  11. Dietary effects of adenosine monophosphate to enhance growth, digestibility, innate immune responses and stress resistance of juvenile red sea bream, Pagrus major.

    Science.gov (United States)

    Hossain, Md Sakhawat; Koshio, Shunsuke; Ishikawa, Manabu; Yokoyama, Saichiro; Sony, Nadia Mahjabin

    2016-09-01

    Our study explored the dietary effects of adenosine monophosphate (AMP) to enhance growth, digestibility, innate immune responses and stress resistance of juvenile red sea bream. A semi-purified basal diet supplemented with 0% (Control), 0.1% (AMP-0.1), 0.2% (AMP-0.2), 0.4% (AMP-0.4) and 0.8% (AMP-0.8) purified AMP to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (mean initial weight 3.4 g) for 56 days. The results indicated that dietary AMP supplements tended to improve growth performances. One of the best ones was found in diet group AMP-0.2, followed by diet groups AMP-0.1, AMP-0.4 and AMP-0.8. The Apparent digestibility coefficients (dry matter, protein and lipid) also improved by AMP supplementation and the significantly highest dry matter digestibility was observed in diet group AMP-0.2. Fish fed diet groups AMP-0.2 and AMP-0.4 had significantly higher peroxidase and bactericidal activities than fish fed the control diet. Nitro-blue-tetrazolium (NBT) activity was found to be significantly (P  0.05) by dietary supplementation. In contrast, catalase activity decreased with AMP supplementation. Moreover, the fish fed AMP supplemented diets had better improvement (P red sea bream. The regression analysis revealed that a dietary AMP supplementation between 0.2 and 0.4% supported weight gain and lysozyme activity as a marker of immune functions for red sea bream, which is also inline with the most of the growth and health performance parameters of fish under present experimental conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Effects of dietary administration of guanosine monophosphate on the growth, digestibility, innate immune responses and stress resistance of juvenile red sea bream, Pagrus major.

    Science.gov (United States)

    Hossain, Md Sakhawat; Koshio, Shunsuke; Ishikawa, Manabu; Yokoyama, Saichiro; Sony, Nadia Mahjabin

    2016-10-01

    The present study explored the dietary administration effects of guanosine monophosphate (GMP) on growth, digestibility, innate immune responses and stress resistance of juvenile red sea bream, Pagrus major. A semi-purified basal diet supplemented with 0% (Control), 0.1% (GMP-0.1), 0.2% (GMP-0.2), 0.4% (GMP-0.4) and 0.8% (GMP-0.8) purified GMP to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (mean initial weight 3.4 g) for 56 days. The obtained results clearly indicated that, growth performance of red sea bream enhanced by dietary GMP supplementation compared to control and significantly higher final weight was found in fish fed diet group GMP-0.4. Specific growth rate (SGR) and percent weight gain (%WG) also significantly higher in diet group GMP-0.4 in compared to control and it was not differed (P > 0.05) with diet group GMP-0.8. Feed intake significantly increased with the supplementation of GMP. Feed conversion efficiency (FCE) and protein efficiency ratio (PER) also improved (P  0.05) by GMP supplementation. In contrast, catalase activity decreased with GMP supplementation. In terms of oxidative stress GMP-0.2 showed best condition with low oxidative stress and high antioxidant level. Moreover, the fish fed GMP supplemented diets had better improvement (P red sea bream, which is also in line with the most of the growth performance and health parameters of the fish. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Overexpression of cyclic adenosine monophosphate effluent protein MRP4 induces an altered response to β-adrenergic stimulation in the senescent rat heart.

    Science.gov (United States)

    Carillion, Aude; Feldman, Sarah; Jiang, Cheng; Atassi, Fabrice; Na, Na; Mougenot, Nathalie; Besse, Sophie; Hulot, Jean-Sébastien; Riou, Bruno; Amour, Julien

    2015-02-01

    In the senescent heart, the positive inotropic response to β-adrenoceptor stimulation is reduced, partly by dysregulation of β1- and β3-adrenoceptors. The multidrug resistance protein 4 (MRP4) takes part in the control of intracellular cyclic adenosine monophosphate concentration by controlling its efflux but the role of MRP4 in the β-adrenergic dysfunction of the senescent heart remains unknown. The β-adrenergic responses to isoproterenol were investigated in vivo (stress echocardiography) and in vitro (isolated cardiomyocyte by Ionoptix with sarcomere shortening and calcium transient) in young (3 months old) and senescent (24 months old) rats pretreated or not with MK571, a specific MRP4 inhibitor. MRP4 was quantified in left ventricular homogenates by Western blotting. Data are mean ± SD expressed as percent of baseline value. The positive inotropic effect of isoproterenol was reduced in senescent rats in vivo (left ventricular shortening fraction 120 ± 16% vs. 158 ± 20%, P < 0.001, n = 16 rats) and in vitro (sarcomere shortening 129 ± 37% vs. 148 ± 35%, P = 0.004, n = 41 or 43 cells) as compared to young rats. MRP4 expression increased 3.6-fold in senescent compared to young rat myocardium (P = 0.012, n = 8 rats per group). In senescent rats, inhibition of MRP4 by MK571 restored the positive inotropic effect of isoproterenol in vivo (143 ± 11%, n = 8 rats). In vitro in senescent cardiomyocytes pretreated with MK571, both sarcomere shortening (161 ± 45% vs. 129 ± 37%, P = 0.007, n = 41 cells per group) and calcium transient amplitude (132 ± 25% vs. 113 ± 27%, P = 0.007) increased significantly. MRP4 overexpression contributes to the reduction of the positive inotropic response to β-adrenoceptor stimulation in the senescent heart.

  14. Cyclic adenosine monophosphate metabolism in synaptic growth, strength, and precision: neural and behavioral phenotype-specific counterbalancing effects between dnc phosphodiesterase and rut adenylyl cyclase mutations.

    Science.gov (United States)

    Ueda, Atsushi; Wu, Chun-Fang

    2012-03-01

    Two classic learning mutants in Drosophila, rutabaga (rut) and dunce (dnc), are defective in cyclic adenosine monophosphate (cAMP) synthesis and degradation, respectively, exhibiting a variety of neuronal and behavioral defects. We ask how the opposing effects of these mutations on cAMP levels modify subsets of phenotypes, and whether any specific phenotypes could be ameliorated by biochemical counter balancing effects in dnc rut double mutants. Our study at larval neuromuscular junctions (NMJs) demonstrates that dnc mutations caused severe defects in nerve terminal morphology, characterized by unusually large synaptic boutons and aberrant innervation patterns. Interestingly, a counterbalancing effect led to rescue of the aberrant innervation patterns but the enlarged boutons in dnc rut double mutant remained as extreme as those in dnc. In contrast to dnc, rut mutations strongly affect synaptic transmission. Focal loose-patch recording data accumulated over 4 years suggest that synaptic currents in rut boutons were characterized by unusually large temporal dispersion and a seasonal variation in the amount of transmitter release, with diminished synaptic currents in summer months. Experiments with different rearing temperatures revealed that high temperature (29-30°C) decreased synaptic transmission in rut, but did not alter dnc and wild-type (WT). Importantly, the large temporal dispersion and abnormal temperature dependence of synaptic transmission, characteristic of rut, still persisted in dnc rut double mutants. To interpret these results in a proper perspective, we reviewed previously documented differential effects of dnc and rut mutations and their genetic interactions in double mutants on a variety of physiological and behavioral phenotypes. The cases of rescue in double mutants are associated with gradual developmental and maintenance processes whereas many behavioral and physiological manifestations on faster time scales could not be rescued. We discuss

  15. Visualization of drug-nucleic acid interactions at atomic resolution. VIII. Structures of two ethidium/dinucleoside monophosphate crystalline complexes containing ethidium: cytidylyl(3'-5') guanosine

    International Nuclear Information System (INIS)

    Jain, S.C.; Sobell, H.M.

    1984-01-01

    This paper describes two complexes containing ethidium and the dinucleoside monophosphate, cytidylyl(3'-5')guanosine (CpG). Both crystals are monoclinic, space group P2 1 , with unit cell dimensions as follows: modification 1: a = 13.64 A, b = 32.16 A, c = 14.93 A, β = 114.8 0 and modification 2: a = 13.79 A, b = 31.94 A, c = 15.66 A, β = 117.5 0 . Each structure has been solved to atomic resolution and refined by Fourier and least squares methods; the first has been refined to a residual of 0.187 on 1903 reflections, while the second has been refined to a residual of 0.187 on 1001 reflections. The asymmetric unit in both structures contains two ethidium molecules and two CpG molecules; the first structure has 30 water molecules (a total of 158 non-hydrogen atoms), while the second structure has 19 water molecules (a total of 147 non-hydrogen atoms). Both structures demonstrate intercalation of ethidium between base-paired CpG dimers. In addition, ethidium molecules stack on either side of the intercalated duplex, being related by a unit cell translation along the a axis. The basic feature of the sugar-phosphate chains accompanying ethidium intercalation in both structures is: C3' endo (3'-5') C2' endo. This mixed sugar-puckering pattern has been observed in all previous studies of ethidium intercalation and is a feature common to other drug-nucleic acid structural studies carried out in the authors laboratory. The authors discussed this further in this paper and in the accompanying papers

  16. Involvement of adenosine monophosphate-activated protein kinase in the influence of timed high-fat evening diet on the hepatic clock and lipogenic gene expression in mice.

    Science.gov (United States)

    Huang, Yan; Zhu, Zengyan; Xie, Meilin; Xue, Jie

    2015-09-01

    A high-fat diet may result in changes in hepatic clock gene expression, but potential mechanisms are not yet elucidated. Adenosine monophosphate-activated protein kinase (AMPK) is a serine/threonine protein kinase that is recognized as a key regulator of energy metabolism and certain clock genes. Therefore, we hypothesized that AMPK may be involved in the alteration of hepatic clock gene expression under a high-fat environment. This study aimed to examine the effects of timed high-fat evening diet on the activity of hepatic AMPK, clock genes, and lipogenic genes. Mice with hyperlipidemic fatty livers were induced by orally administering high-fat milk via gavage every evening (19:00-20:00) for 6 weeks. Results showed that timed high-fat diet in the evening not only decreased the hepatic AMPK protein expression and activity but also disturbed its circadian rhythm. Accordingly, the hepatic clock genes, including clock, brain-muscle-Arnt-like 1, cryptochrome 2, and period 2, exhibited prominent changes in their expression rhythms and/or amplitudes. The diurnal rhythms of the messenger RNA expression of peroxisome proliferator-activated receptorα, acetyl-CoA carboxylase 1α, and carnitine palmitoyltransferase 1 were also disrupted; the amplitude of peroxisome proliferator-activated receptorγcoactivator 1α was significantly decreased at 3 time points, and fatty liver was observed. These findings demonstrate that timed high-fat diet at night can change hepatic AMPK protein levels, activity, and circadian rhythm, which may subsequently alter the circadian expression of several hepatic clock genes and finally result in the disorder of hepatic lipogenic gene expression and the formation of fatty liver. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Involvement of nitric oxide-cyclic guanosine monophosphate pathway in the antidepressant-like effect of tropisetron and ondansetron in mice forced swimming test and tail suspension test.

    Science.gov (United States)

    Haj-Mirzaian, Arya; Kordjazy, Nastaran; Amiri, Shayan; Haj-Mirzaian, Arvin; Amini-Khoei, Hossien; Ostadhadi, Sattar; Dehpour, AhmadReza

    2016-06-05

    Antidepressant-like effects of 5-hydroxytryptamine subtype 3 (5-HT3) antagonists including tropisetron and ondansetron have been previously demonstrated in the literature. It was reported that stimulation of 5-HT3 receptors activate the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway, which is involved in regulation of behavioral and emotional functions. In our study, treating animals with tropisetron (5, 10, and 30mg/kg) and ondansetron (0.01 and 0.1µg/kg) significantly decreased the immobility time in forced swimming test (FST) and tail-suspension test (TST). Co-administration of subeffective doses of tropisetron (1mg/kg) and ondansetron (0.001µg/kg) with subeffective dose of l-NAME (10mg/kg, nonselective NO synthase (NOS) inhibitor) and 7-nitroindazole (25mg/kg, neural NOS inhibitor) exerted antidepressant-like effect in FST and TST, while aminoguanidine (50mg/kg, inducible NOS inhibitor) did not enhance the antidepressant-like effect of 5-HT3 antagonists. Besides, l-arginine (750mg/kg, NO precursor) and sildenafil (5mg/kg, phosphodiesterase inhibitor) suppressed the anti-immobility effect of 5-HT3 antagonists. None of the treatments altered the locomotor behavior of mice in open-field test. Also, hippocampal (but not cortical) nitrite level was significantly lower in tropisetron and ondansetron-treated mice compared with saline-injected mice. Also, co-administration of 7-nitroindazole with tropisetron or ondansetron caused a significant decrease in hippocampal nitrite levels. In conclusion, we suggest that antidepressant-like effect of tropisetron and ondansetron are partially mediated by modulation of NO-cGMP pathway. Copyright © 2016. Published by Elsevier B.V.

  18. Are dinucleoside monophosphates relevant models for the study of DNA intrastrand cross-link lesions? The example of g[8-5m]T.

    Science.gov (United States)

    Garrec, Julian; Dumont, Elise

    2014-07-21

    Oxidatively generated tandem lesions such as G[8-5m]T pose a potent threat to genome integrity. Direct experimental studies of the kinetics and thermodynamics of a specific lesion within DNA are very challenging, mostly due to the variety of products that can be formed in oxidative conditions. Dinucleoside monophosphates (DM) involving only the reactive nucleobases in water represent appealing alternative models on which most physical chemistry and structural techniques can be applied. However, it is not yet clear how relevant these models are. Here, we present QM/MM MD simulations of the cyclization step involved in the formation of G[8-5m]T from the guanine-thymine (GpT) DM in water, with the aim of comparing our results to our previous investigation of the same reaction in DNA ( Garrec , J. , Patel , C. , Rothlisberger , U. , and Dumont , E. ( 2012 ) J. Am. Chem. Soc. 134 , 2111 - 2119 ). We show that, despite the different levels of preorganization of the two systems, the corresponding reactions share many energetic and structural characteristics. The main difference lies in the angle between the G and T bases, which is slightly higher in the transition state (TS) and product of the reaction in water than in the reaction in DNA. This effect is due to the Watson-Crick H-bonds, which are absent in the {GpT+water} system and restrain the relative positioning of the reactive nucleobases in DNA. However, since the lesion is accommodated easily in the DNA macromolecule, the induced energetic penalty is relatively small. The high similarity between the two reactions strongly supports the use of GpT in water as a model of the corresponding reaction in DNA.

  19. Visualization of drug-nucleic acid interactions at atomic resolution. II. Structure of an ethidium/dinucleoside monophosphate crystalline complex, ethidium:5-iodocytidylyl(3'5')guanosine

    Energy Technology Data Exchange (ETDEWEB)

    Jain, S C; Tsair, C C; Sobell, H M

    1977-01-01

    Ethidium forms a second crystalline complex with the dinucleoside monophosphate 5-iodocytidyl(3'-5')guanosine (iodoCpG). These crystals are monoclinic, P2/sub 1/, with a = 14.06 A, b = 32.34 A, c = 16.53 A, ..beta.. = 117.8/sup 0/. The structure has been solved to atomic resolution using rigid-body Patterson vector search and Fourier methods, and refined by full matrix least-squares to a residual of 0.16 on 3180 observed reflections. Both iodoCpG molecules are hydrogen-bonded together by guanine.cytosine Watson--Crick base-pairing. Adjacent base-pairs within this paired iodoCpG structure and between neighboring iodoCpG molecules in adjoining unit cells are separated by 6.7 A. Approximate 2-fold symmetry is used in the interaction; this reflects the pseudo-2-fold symmetry axis of the phenanthridinium ring system in ethidium coinciding with the approximate 2-fold axis relating base-paired iodoCpG molecules. The phenyl and ethyl groups of the intercalated ethidium molecule lie in the narrow groove of the miniature iodoCpG double-helix. The stacked ethidium, however, lies in the opposite direction, its phenyl and ethyl groups neighboring iodine atoms on cytosine residues. Base-pairs within the paired nucleotide units are related by a twist of about 8/sup 0/. The magnitude of this angular twist reflects conformational changes in the sugar--phosphate chains accompanying intercalation. These primarily reflect the differences in ribose sugar ring puckering that are observed (i.e., both iodocytidine residues have C3' endo sugar conformations, while both guanosine residues have C2' endo sugar conformations), and alterations in the glycosidic torsional angles that describe the base-sugar orientation.

  20. Visualization of drug-nucleic acid interactions at atomic resolution. I. Structure of an ethidium/dinucleoside monophosphate crystalline complex, ethidium:5-iodouridylyl(3'5')adenosine

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C C; Jain, S C; Sobell, H M

    1977-01-01

    Ethidium forms a crystalline complex with the dinucleoside monophosphate 5-iodouridyly(3'-5')adenosine (iodoUpA). These crystals are monoclinic, space group C2, with unit cell dimensions, a = 28.45 A, b = 13.54 A, c = 34.13 A, ..beta.. = 98.6/sup 0/. The structure has been solved to atomic resolution by Patterson and Fourier methods, and refined by full matrix least-squares to a residual of 0.20 on 2017 observed reflections. The asymmetric unit contains two ethidium molecules, two iodoUpA molecules and 27 water molecules, a total of 155 atoms excluding hydrogens. The two iodoUpA molecules are held together by adenine.uracil Watson--Crick-type base-pairing. Adjacent base-pairs within this paired iodoUpA structure and between neighboring iodoUpA molecules in adjoining unit cells are separated by about 6.7 A; this separation results from intercalative binding by one ethidium molecule and stacking by the other ethidium molecule above and below the base-pairs. Non-crystallographic 2-fold symmetry is utilized in this model drug--nucleic acid interaction, the intercalated ethidium molecule being oriented such that its phenyl and ethyl groups lie in the narrow groove of the miniature nucleic acid double-helix. Base-pairs within the paired nucleotide units are related by a twist of 8/sup 0/. The magnitude of this angular twist is related to conformational changes in the sugar--phosphate chains that accompany drug intercalation. These changes partly reflect the differences in ribose sugar ring puckering that are observed. Additional small but systematic changes occur in torsional angles that involve the phosphodiester linkages and the C4'--C5' bond. Solution studies have indicated a marked sequence-specific binding preference in ethidium--dinucleotide interactions, and a probable structural explanation for this is provided by this study.

  1. Enhanced Bacterial α(2,6-Sialyltransferase Reaction through an Inhibition of Its Inherent Sialidase Activity by Dephosphorylation of Cytidine-5'-Monophosphate.

    Directory of Open Access Journals (Sweden)

    Ji-Yeon Kang

    Full Text Available Bacterial α(2,6-sialyltransferases (STs from Photobacterium damsela, Photobacterium sp. JT-ISH-224, and P. leiognathi JT-SHIZ-145 were recombinantly expressed in Escherichia coli and their ST activities were compared directly using a galactosylated bi-antennary N-glycan as an acceptor substrate. In all ST reactions, there was an increase of sialylated glycans at shorter reaction times and later a decrease in prolonged reactions, which is related with the inherent sialidase activities of bacterial STs. These sialidase activities are greatly increased by free cytidine monophosphate (CMP generated from a donor substrate CMP-N-acetylneuraminic acid (CMP-Neu5Ac during the ST reactions. The decrease of sialylated glycans in prolonged ST reaction was prevented through an inhibition of sialidase activity by simple treatment of alkaline phosphatase (AP, which dephosphorylates CMP to cytidine. Through supplemental additions of AP and CMP-Neu5Ac to the reaction using the recombinant α(2,6-ST from P. leiognathi JT-SHIZ-145 (P145-ST, the content of bi-sialylated N-glycan increased up to ~98% without any decrease in prolonged reactions. This optimized P145-ST reaction was applied successfully for α(2,6-sialylation of asialofetuin, and this resulted in a large increase in the populations of multi-sialylated N-glycans compared with the reaction without addition of AP and CMP-Neu5Ac. These results suggest that the optimized reaction using the recombinant P145-ST readily expressed from E. coli has a promise for economic glycan synthesis and glyco-conjugate remodeling.

  2. cAMP signaling in skeletal muscle adaptation: hypertrophy, metabolism, and regeneration

    Science.gov (United States)

    Stewart, Randi

    2012-01-01

    Among organ systems, skeletal muscle is perhaps the most structurally specialized. The remarkable subcellular architecture of this tissue allows it to empower movement with instructions from motor neurons. Despite this high degree of specialization, skeletal muscle also has intrinsic signaling mechanisms that allow adaptation to long-term changes in demand and regeneration after acute damage. The second messenger adenosine 3′,5′-monophosphate (cAMP) not only elicits acute changes within myofibers during exercise but also contributes to myofiber size and metabolic phenotype in the long term. Strikingly, sustained activation of cAMP signaling leads to pronounced hypertrophic responses in skeletal myofibers through largely elusive molecular mechanisms. These pathways can promote hypertrophy and combat atrophy in animal models of disorders including muscular dystrophy, age-related atrophy, denervation injury, disuse atrophy, cancer cachexia, and sepsis. cAMP also participates in muscle development and regeneration mediated by muscle precursor cells; thus, downstream signaling pathways may potentially be harnessed to promote muscle regeneration in patients with acute damage or muscular dystrophy. In this review, we summarize studies implicating cAMP signaling in skeletal muscle adaptation. We also highlight ligands that induce cAMP signaling and downstream effectors that are promising pharmacological targets. PMID:22354781

  3. Effect of two non-synonymous ecto-5'-nucleotidase variants on the genetic architecture of inosine 5'-monophosphate (IMP) and its degradation products in Japanese Black beef.

    Science.gov (United States)

    Uemoto, Yoshinobu; Ohtake, Tsuyoshi; Sasago, Nanae; Takeda, Masayuki; Abe, Tsuyoshi; Sakuma, Hironori; Kojima, Takatoshi; Sasaki, Shinji

    2017-11-13

    Umami is a Japanese term for the fifth basic taste and is an important sensory property of beef palatability. Inosine 5'-monophosphate (IMP) contributes to umami taste in beef. Thus, the overall change in concentration of IMP and its degradation products can potentially affect the beef palatability. In this study, we investigated the genetic architecture of IMP and its degradation products in Japanese Black beef. First, we performed genome-wide association study (GWAS), candidate gene analysis, and functional analysis to detect the causal variants that affect IMP, inosine, and hypoxanthine. Second, we evaluated the allele frequencies in the different breeds, the contribution of genetic variance, and the effect on other economical traits using the detected variants. A total of 574 Japanese Black cattle were genotyped using the Illumina BovineSNP50 BeadChip and were then used for GWAS. The results of GWAS showed that the genome-wide significant single nucleotide polymorphisms (SNPs) on BTA9 were detected for IMP, inosine, and hypoxanthine. The ecto-5'-nucleotidase (NT5E) gene, which encodes the enzyme NT5E for the extracellular degradation of IMP to inosine, was located near the significant region on BTA9. The results of candidate gene analysis and functional analysis showed that two non-synonymous SNPs (c.1318C > T and c.1475 T > A) in NT5E affected the amount of IMP and its degradation products in beef by regulating the enzymatic activity of NT5E. The Q haplotype showed a positive effect on IMP and a negative effect on the enzymatic activity of NT5E in IMP degradation. The two SNPs were under perfect linkage disequilibrium in five different breeds, and different haplotype frequencies were seen among breeds. The two SNPs contribute to about half of the total genetic variance in IMP, and the results of genetic relationship between IMP and its degradation products showed that NT5E affected the overall concentration balance of IMP and its degradation products

  4. Regulation of cessation of respiration and killing by cyclic 3',5'-adenosine monophosphate and its receptor protein after far-ultraviolet irradiation of Escherichia coli

    International Nuclear Information System (INIS)

    Swenson, P.A.; Schenley, R.L.; Joshi, J.G.

    1978-01-01

    When Escherichia coli B/r cultures are irradiated with ultraviolet light (UV) (254 nm), those cells that are killed stop respiring by 60 min after irradiation. Post-UV treatment with cyclic adenosine 3',5'-adenosine monophosphate (cAMP) causes more cells to stop respiring and to die. We have studied these effects at a UV fluence of 52 I/m 2 in a a wild-type E. coli K 12 strain and in mutants defective in cAMP metabolism. Strain CA 8,000 has crp + and cya + genes for the cAMP receptor protein (CRP) (required for transcription of operons regulated by cAMP) and for adenylate cyclase, respectively; CA 7901 is crp - ; and CA 8306 is a cya deletion (Δ). The wild-type culture showed a small transient cessation of respiration, and addition of cAMP caused cessation to be nearly complete. The crp - culture showed no evidence of cessation of respiration, and cAMP had no effect. The Δ cya mutant also showed no cessation of respiration, but cAMP (5 mM) caused as complete inhibition as in the wild type. cAMP caused a 10-fold loss in viability of UV-irradiated wild-type and Δ cya liquid cultures but had no effect on the cpr - culture. Respiration and viability changes were also studied in a double mutant, CA8404 Δ cya crp*, which has an altered CRP that is, with respect to the lac operon, independent of cAMP. The respiration response to UV was similar to that of the wild-type culture, and both respiration and viability of cells in liquid culture were sensitive to cAMP. The survival data, obtained by plating immediately after irradiation, show the wild type, Δ cya strains, and Δ cya crp* to be equally sensitive and the crp - strain to be more resistant. We conclude that cessation of respiration and cell killing after UV irradiation are regulated by cAMP and the CRP. (orig.) [de

  5. Roles of p300 and cyclic adenosine monophosphate response element binding protein in high glucose-induced hypoxia-inducible factor 1α inactivation under hypoxic conditions.

    Science.gov (United States)

    Ding, Lingtao; Yang, Minlie; Zhao, Tianlan; Lv, Guozhong

    2017-05-01

    Given the high prevalence of diabetes and burn injuries worldwide, it is essential to dissect the underlying mechanism of delayed burn wound healing in diabetes patients, especially the high glucose-induced hypoxia-inducible factor 1 (HIF-1)-mediated transcription defects. Human umbilical vein endothelial cells were cultured with low or high concentrations of glucose. HIF-1α-induced vascular endothelial growth factor (VEGF) transcription was measured by luciferase assay. Immunofluorescence staining was carried out to visualize cyclic adenosine monophosphate response element binding protein (CREB) localization. Immunoprecipitation was carried out to characterize the association between HIF-1α/p300/CREB. To test whether p300, CREB or p300+CREB co-overexpression was sufficient to rescue the HIF-1-mediated transcription defect after high glucose exposure, p300, CREB or p300+CREB co-overexpression were engineered, and VEGF expression was quantified. Finally, in vitro angiogenesis assay was carried out to test whether the high glucose-induced angiogenesis defect is rescuable by p300 and CREB co-overexpression. Chronic high glucose treatment resulted in impaired HIF-1-induced VEGF transcription and CREB exclusion from the nucleus. P300 or CREB overexpression alone cannot rescue high glucose-induced HIF-1α transcription defects. In contrast, co-overexpression of p300 and CREB dramatically ameliorated high glucose-induced impairment of HIF-1-mediated VEGF transcription, as well as in vitro angiogenesis. Finally, we showed that co-overexpression of p300 and CREB rectifies the dissociation of HIF-1α-p300-CREB protein complex in chronic high glucose-treated cells. Both p300 and CREB are required for the function integrity of HIF-1α transcription machinery and subsequent angiogenesis, suggesting future studies to improve burn wound healing might be directed to optimization of the interaction between p300, CREB and HIF-1α. © 2016 The Authors. Journal of Diabetes

  6. Acridone-based inhibitors of inosine 5'-monophosphate dehydrogenase: discovery and SAR leading to the identification of N-(2-(6-(4-ethylpiperazin-1-yl)pyridin-3-yl)propan-2-yl)-2- fluoro-9-oxo-9,10-dihydroacridine-3-carboxamide (BMS-566419).

    Science.gov (United States)

    Watterson, Scott H; Chen, Ping; Zhao, Yufen; Gu, Henry H; Dhar, T G Murali; Xiao, Zili; Ballentine, Shelley K; Shen, Zhongqi; Fleener, Catherine A; Rouleau, Katherine A; Obermeier, Mary; Yang, Zheng; McIntyre, Kim W; Shuster, David J; Witmer, Mark; Dambach, Donna; Chao, Sam; Mathur, Arvind; Chen, Bang-Chi; Barrish, Joel C; Robl, Jeffrey A; Townsend, Robert; Iwanowicz, Edwin J

    2007-07-26

    Inosine monophosphate dehydrogenase (IMPDH), a key enzyme in the de novo synthesis of guanosine nucleotides, catalyzes the irreversible nicotinamide-adenine dinucleotide dependent oxidation of inosine-5'-monophosphate to xanthosine-5'-monophosphate. Mycophenolate Mofetil (MMF), a prodrug of mycophenolic acid, has clinical utility for the treatment of transplant rejection based on its inhibition of IMPDH. The overall clinical benefit of MMF is limited by what is generally believed to be compound-based, dose-limiting gastrointestinal (GI) toxicity that is related to its specific pharmacokinetic characteristics. Thus, development of an IMPDH inhibitor with a novel structure and a different pharmacokinetic profile may reduce the likelihood of GI toxicity and allow for increased efficacy. This article will detail the discovery and SAR leading to a novel and potent acridone-based IMPDH inhibitor 4m and its efficacy and GI tolerability when administered orally in a rat adjuvant arthritis model.

  7. Basic digital signal processing

    CERN Document Server

    Lockhart, Gordon B

    1985-01-01

    Basic Digital Signal Processing describes the principles of digital signal processing and experiments with BASIC programs involving the fast Fourier theorem (FFT). The book reviews the fundamentals of the BASIC program, continuous and discrete time signals including analog signals, Fourier analysis, discrete Fourier transform, signal energy, power. The text also explains digital signal processing involving digital filters, linear time-variant systems, discrete time unit impulse, discrete-time convolution, and the alternative structure for second order infinite impulse response (IIR) sections.

  8. Conservation and divergence of the cyclic adenosine monophosphate-protein kinase A (cAMP–PKA) pathway in two plant-pathogenic fungi: Fusarium graminearum and F. verticillioides

    Science.gov (United States)

    The cyclic AMP (cAMP)-PKA pathway is a central signaling cascade that transmits extracellular stimuli and governs cell responses through the second messenger cAMP. The importance of cAMP signaling in fungal biology has been well documented. Two key conserved components, adenylate cyclase (AC) and ca...

  9. Valsartan regulates the interaction of angiotensin II type 1 receptor and endothelial nitric oxide synthase via Src/PI3K/Akt signalling.

    Science.gov (United States)

    Su, Kuo-Hui; Tsai, Jin-Yi; Kou, Yu Ru; Chiang, An-Na; Hsiao, Sheng-Huang; Wu, Yuh-Lin; Hou, Hsin-Han; Pan, Ching-Chian; Shyue, Song-Kun; Lee, Tzong-Shyuan

    2009-06-01

    Valsartan, a selective angiotensin II type 1 receptor (AT1R) blocker, has beneficial effects in the cardiovascular system in part by its increase of nitric oxide (NO) bioavailability, yet the mechanisms are unclear. We investigated the molecular mechanisms underlying this effect in endothelial cells (ECs). NO production was examined by Griess reagent assay, DAF-2 DA fluorescence staining and cGMP ELISA kits. Protein interaction was determined by western blotting and immunoprecipitation. Treating bovine or human aortic ECs with valsartan increased NO production, as evidenced by elevated level of stable NO metabolites and intracellular cGMP. Valsartan increased the phosphorylation but not the protein level of endothelial NO synthase (eNOS). Inhibition of phosphoinositide-3 kinase (PI3K)/Akt and Src pathways by specific inhibitors suppressed valsartan-induced NO release. In addition, valsartan increased the tyrosine residue phosphorylation of AT1R, which was attenuated by inhibition of Src but not PI3K activities. Valsartan also suppressed the interaction of eNOS and AT1R, which was blocked by Src or PI3K inhibition. Valsartan-induced NO production in ECs is mediated through Src/PI3K/Akt-dependent phosphorylation of eNOS. Valsartan-induced AT1R phosphorylation depends on Src but not PI3K, whereas valsartan-induced suppression of AT1R-eNOS interaction depends on Src/PI3K/Akt signalling. These results indicate a novel vasoprotective mechanism of valsartan in upregulating NO production in ECs.

  10. Decoding spatial and temporal features of neuronal cAMP/PKA signaling with FRET biosensors.

    Science.gov (United States)

    Castro, Liliana R V; Guiot, Elvire; Polito, Marina; Paupardin-Tritsch, Daniéle; Vincent, Pierre

    2014-02-01

    Cyclic adenosine monophosphate (cAMP) and the cyclic-AMP-dependent protein kinase (PKA) regulate a plethora of cellular functions in virtually all eukaryotic cells. In neurons, the cAMP/PKA signaling cascade controls a number of biological properties such as axonal growth, pathfinding, efficacy of synaptic transmission, regulation of excitability, or long term changes. Genetically encoded optical biosensors for cAMP or PKA are considerably improving our understanding of these processes by providing a real-time measurement in living neurons. In this review, we describe the recent progress made in the creation of biosensors for cAMP or PKA activity. These biosensors revealed profound differences in the amplitude of the cAMP signal evoked by neuromodulators between various neuronal preparations. These responses can be resolved at the level of individual neurons, also revealing differences related to the neuronal type. At the sub-cellular level, biosensors reported different signal dynamics in domains like dendrites, cell body, nucleus, and axon. Combining this imaging approach with pharmacology or genetic models points at phosphodiesterases and phosphatases as critical regulatory proteins. Biosensor imaging will certainly emerge as a forefront tool to decipher the subtle mechanics of intracellular signaling. This will certainly help us to understand the mechanism of action of current drugs and foster the development of novel molecules for neuropsychiatric diseases. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Retroactive signaling in short signaling pathways.

    Directory of Open Access Journals (Sweden)

    Jacques-Alexandre Sepulchre

    Full Text Available In biochemical signaling pathways without explicit feedback connections, the core signal transduction is usually described as a one-way communication, going from upstream to downstream in a feedforward chain or network of covalent modification cycles. In this paper we explore the possibility of a new type of signaling called retroactive signaling, offered by the recently demonstrated property of retroactivity in signaling cascades. The possibility of retroactive signaling is analysed in the simplest case of the stationary states of a bicyclic cascade of signaling cycles. In this case, we work out the conditions for which variables of the upstream cycle are affected by a change of the total amount of protein in the downstream cycle, or by a variation of the phosphatase deactivating the same protein. Particularly, we predict the characteristic ranges of the downstream protein, or of the downstream phosphatase, for which a retroactive effect can be observed on the upstream cycle variables. Next, we extend the possibility of retroactive signaling in short but nonlinear signaling pathways involving a few covalent modification cycles.

  12. Akt/PKB activation and insulin signaling: a novel insulin signaling pathway in the treatment of type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Mackenzie RWA

    2014-02-01

    Full Text Available Richard WA Mackenzie, Bradley T Elliott Department of Human and Health Sciences, Facility of Science and Technology, University of Westminster, London, UK Abstract: Type 2 diabetes is a metabolic disease categorized primarily by reduced insulin sensitivity, β-cell dysfunction, and elevated hepatic glucose production. Treatments reducing hyperglycemia and the secondary complications that result from these dysfunctions are being sought after. Two distinct pathways encourage glucose transport activity in skeletal muscle, ie, the contraction-stimulated pathway reliant on Ca2+/5′-monophosphate-activated protein kinase (AMPK-dependent mechanisms and an insulin-dependent pathway activated via upregulation of serine/threonine protein kinase Akt/PKB. Metformin is an established treatment for type 2 diabetes due to its ability to increase peripheral glucose uptake while reducing hepatic glucose production in an AMPK-dependent manner. Peripheral insulin action is reduced in type 2 diabetics whereas AMPK signaling remains largely intact. This paper firstly reviews AMPK and its role in glucose uptake and then focuses on a novel mechanism known to operate via an insulin-dependent pathway. Inositol hexakisphosphate (IP6 kinase 1 (IP6K1 produces a pyrophosphate group at the position of IP6 to generate a further inositol pyrophosphate, ie, diphosphoinositol pentakisphosphate (IP7. IP7 binds with Akt/PKB at its pleckstrin homology domain, preventing interaction with phosphatidylinositol 3,4,5-trisphosphate, and therefore reducing Akt/PKB membrane translocation and insulin-stimulated glucose uptake. Novel evidence suggesting a reduction in IP7 production via IP6K1 inhibition represents an exciting therapeutic avenue in the treatment of insulin resistance. Metformin-induced activation of AMPK is a key current intervention in the management of type 2 diabetes. However, this treatment does not seem to improve peripheral insulin resistance. In light of this

  13. Clathrin-dependent internalization, signaling, and metabolic processing of guanylyl cyclase/natriuretic peptide receptor-A.

    Science.gov (United States)

    Somanna, Naveen K; Mani, Indra; Tripathi, Satyabha; Pandey, Kailash N

    2018-04-01

    Cardiac hormones, atrial and brain natriuretic peptides (ANP and BNP), have pivotal roles in renal hemodynamics, neuroendocrine signaling, blood pressure regulation, and cardiovascular homeostasis. Binding of ANP and BNP to the guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) induces rapid internalization and trafficking of the receptor via endolysosomal compartments, with concurrent generation of cGMP. However, the mechanisms of the endocytotic processes of NPRA are not well understood. The present study, using 125 I-ANP binding assay and confocal microscopy, examined the function of dynamin in the internalization of NPRA in stably transfected human embryonic kidney-293 (HEK-293) cells. Treatment of recombinant HEK-293 cells with ANP time-dependently accelerated the internalization of receptor from the cell surface to the cell interior. However, the internalization of ligand-receptor complexes of NPRA was drastically decreased by the specific inhibitors of clathrin- and dynamin-dependent receptor internalization, almost 85% by monodansylcadaverine, 80% by chlorpromazine, and 90% by mutant dynamin, which are specific blockers of endocytic vesicle formation. Visualizing the internalization of NPRA and enhanced GFP-tagged NPRA in HEK-293 cells by confocal microscopy demonstrated the formation of endocytic vesicles after 5 min of ANP treatment; this effect was blocked by the inhibitors of clathrin and by mutant dynamin construct. Our results suggest that NPRA undergoes internalization via clathrin-mediated endocytosis as part of its normal itinerary, including trafficking, signaling, and metabolic degradation.

  14. Basic roles of key molecules connected with NMDAR signaling pathway on regulating learning and memory and synaptic plasticity

    Institute of Scientific and Technical Information of China (English)

    Hui Wang; Rui-Yun Peng

    2016-01-01

    With key roles in essential brain functions ranging from the long-term potentiation (LTP) to synaptic plasticity,the N-methyl-D-aspartic acid receptor (NMDAR) can be considered as one of the fundamental glutamate receptors in the central nervous system.The role of NMDA R was first identified in synaptic plasticity and has been extensively studied.Some molecules,such as Ca2+,postsynaptic density 95 (PSD-95),calcium/calmodulin-dependent protein kinase Ⅱ (CaMK Ⅱ),protein kinase A (PKA),mitogen-activated protein kinase (MAPK) and cyclic adenosine monophosphate (cAMP) responsive element binding protein (CREB),are of special importance in learning and memory.This review mainly focused on the new research of key molecules connected with learning and memory,which played important roles in the NMDAR signaling pathway.

  15. Signal sciences workshop proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.

    1997-05-01

    This meeting is aimed primarily at signal processing and controls. The technical program for the 1997 Workshop includes a variety of efforts in the Signal Sciences with applications in the Microtechnology Area a new program at LLNL and a future area of application for both Signal/Image Sciences. Special sessions organized by various individuals in Seismic and Optical Signal Processing as well as Micro-Impulse Radar Processing highlight the program, while the speakers at the Signal Processing Applications session discuss various applications of signal processing/control to real world problems. For the more theoretical, a session on Signal Processing Algorithms was organized as well as for the more pragmatic, featuring a session on Real-Time Signal Processing.

  16. Signal sciences workshop. Proceedings

    International Nuclear Information System (INIS)

    Candy, J.V.

    1997-01-01

    This meeting is aimed primarily at signal processing and controls. The technical program for the 1997 Workshop includes a variety of efforts in the Signal Sciences with applications in the Microtechnology Area a new program at LLNL and a future area of application for both Signal/Image Sciences. Special sessions organized by various individuals in Seismic and Optical Signal Processing as well as Micro-Impulse Radar Processing highlight the program, while the speakers at the Signal Processing Applications session discuss various applications of signal processing/control to real world problems. For the more theoretical, a session on Signal Processing Algorithms was organized as well as for the more pragmatic, featuring a session on Real-Time Signal Processing

  17. AMP and adenosine are both ligands for adenosine 2B receptor signaling.

    Science.gov (United States)

    Holien, Jessica K; Seibt, Benjamin; Roberts, Veena; Salvaris, Evelyn; Parker, Michael W; Cowan, Peter J; Dwyer, Karen M

    2018-01-15

    Adenosine is considered the canonical ligand for the adenosine 2B receptor (A 2B R). A 2B R is upregulated following kidney ischemia augmenting post ischemic blood flow and limiting tubular injury. In this context the beneficial effect of A 2B R signaling has been attributed to an increase in the pericellular concentration of adenosine. However, following renal ischemia both kidney adenosine monophosphate (AMP) and adenosine levels are substantially increased. Using computational modeling and calcium mobilization assays, we investigated whether AMP could also be a ligand for A 2B R. The computational modeling suggested that AMP interacts with more favorable energy to A 2B R compared with adenosine. Furthermore, AMPαS, a non-hydrolyzable form of AMP, increased calcium uptake by Chinese hamster ovary (CHO) cells expressing the human A 2B R, indicating preferential signaling via the G q pathway. Therefore, a putative AMP-A 2B R interaction is supported by the computational modeling data and the biological results suggest this interaction involves preferential G q activation. These data provide further insights into the role of purinergic signaling in the pathophysiology of renal IRI. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Independent AMP and NAD signaling regulates C2C12 differentiation and metabolic adaptation.

    Science.gov (United States)

    Hsu, Chia George; Burkholder, Thomas J

    2016-12-01

    The balance of ATP production and consumption is reflected in adenosine monophosphate (AMP) and nicotinamide adenine dinucleotide (NAD) content and has been associated with phenotypic plasticity in striated muscle. Some studies have suggested that AMPK-dependent plasticity may be an indirect consequence of increased NAD synthesis and SIRT1 activity. The primary goal of this study was to assess the interaction of AMP- and NAD-dependent signaling in adaptation of C2C12 myotubes. Changes in myotube developmental and metabolic gene expression were compared following incubation with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) and nicotinamide mononucleotide (NMN) to activate AMPK- and NAD-related signaling. AICAR showed no effect on NAD pool or nampt expression but significantly reduced histone H3 acetylation and GLUT1, cytochrome C oxidase subunit 2 (COX2), and MYH3 expression. In contrast, NMN supplementation for 24 h increased NAD pool by 45 % but did not reduce histone H3 acetylation nor promote mitochondrial gene expression. The combination of AMP and NAD signaling did not induce further metabolic adaptation, but NMN ameliorated AICAR-induced myotube reduction. We interpret these results as indication that AMP and NAD contribute to C2C12 differentiation and metabolic adaptation independently.

  19. ECG signal processing

    NARCIS (Netherlands)

    2009-01-01

    A system extracts an ECG signal from a composite signal (308) representing an electric measurement of a living subject. Identification means (304) identify a plurality of temporal segments (309) of the composite signal corresponding to a plurality of predetermined segments (202,204,206) of an ECG

  20. Optimal Signal Quality Index for Photoplethysmogram Signals

    Directory of Open Access Journals (Sweden)

    Mohamed Elgendi

    2016-09-01

    Full Text Available A photoplethysmogram (PPG is a noninvasive circulatory signal related to the pulsatile volume of blood in tissue and is typically collected by pulse oximeters. PPG signals collected via mobile devices are prone to artifacts that negatively impact measurement accuracy, which can lead to a significant number of misleading diagnoses. Given the rapidly increased use of mobile devices to collect PPG signals, developing an optimal signal quality index (SQI is essential to classify the signal quality from these devices. Eight SQIs were developed and tested based on: perfusion, kurtosis, skewness, relative power, non-stationarity, zero crossing, entropy, and the matching of systolic wave detectors. Two independent annotators annotated all PPG data (106 recordings, 60 s each and a third expert conducted the adjudication of differences. The independent annotators labeled each PPG signal with one of the following labels: excellent, acceptable or unfit for diagnosis. All indices were compared using Mahalanobis distance, linear discriminant analysis, quadratic discriminant analysis, and support vector machine with leave-one-out cross-validation. The skewness index outperformed the other seven indices in differentiating between excellent PPG and acceptable, acceptable combined with unfit, and unfit recordings, with overall F 1 scores of 86.0%, 87.2%, and 79.1%, respectively.

  1. Optimal Signal Quality Index for Photoplethysmogram Signals.

    Science.gov (United States)

    Elgendi, Mohamed

    2016-09-22

    A photoplethysmogram (PPG) is a noninvasive circulatory signal related to the pulsatile volume of blood in tissue and is typically collected by pulse oximeters. PPG signals collected via mobile devices are prone to artifacts that negatively impact measurement accuracy, which can lead to a significant number of misleading diagnoses. Given the rapidly increased use of mobile devices to collect PPG signals, developing an optimal signal quality index (SQI) is essential to classify the signal quality from these devices. Eight SQIs were developed and tested based on: perfusion, kurtosis, skewness, relative power, non-stationarity, zero crossing, entropy, and the matching of systolic wave detectors. Two independent annotators annotated all PPG data (106 recordings, 60 s each) and a third expert conducted the adjudication of differences. The independent annotators labeled each PPG signal with one of the following labels: excellent, acceptable or unfit for diagnosis. All indices were compared using Mahalanobis distance, linear discriminant analysis, quadratic discriminant analysis, and support vector machine with leave-one-out cross-validation. The skewness index outperformed the other seven indices in differentiating between excellent PPG and acceptable, acceptable combined with unfit, and unfit recordings, with overall F 1 scores of 86.0%, 87.2%, and 79.1%, respectively.

  2. Second-hand signals

    DEFF Research Database (Denmark)

    Bergenholtz, Carsten

    2014-01-01

    Studies of signaling theory have traditionally focused on the dyadic link between the sender and receiver of the signal. Within a science‐based perspective this framing has led scholars to investigate how patents and publications of firms function as signals. I explore another important type...... used by various agents in their search for and assessment of products and firms. I conclude by arguing how this second‐hand nature of signals goes beyond a simple dyadic focus on senders and receivers of signals, and thus elucidates the more complex interrelations of the various types of agents...

  3. Participation of intracellular signal transduction in the radio-adaptive response induced by low-dose X-irradiation in human embryonic cells

    International Nuclear Information System (INIS)

    Ishii, Keiichiro; Hoshi, Yuko; Iwasaki, Toshiyasu; Watanabe, Masami.

    1996-01-01

    To elucidate the induction mechanism of radio-adaptive response in normal cells, we searched the literatures of the intracellular signal transduction. Furthermore, we examined the induction of radio-adaptive response with or without inhibitors of several kinds of protein kinase. The major results obtained were as follows; (1) According to the literature survey it is revealed that there are 4 intracellular signal transduction pathways which are possibly involved in the induction of radio-adaptive response: pathways depending on cAMP, calcium, cGMP, or protein-tyrosine kinase. (2) Addition of either inhibitor of protein-tyrosine kinase or protein kinase C to the cell culture medium during the low-dose X-irradiation inhibited the induction of radio-adaptive response. However, the addition of inhibitor of cAMP-dependent protein kinase, cGMP-dependent protein kinase, or Ca 2+ -calmodulin kinase II failed to inhibit the induction of radio-adaptive response. (3) These results suggest that the signal induced in cells by low-dose X-irradiation was transduced from protein-tyrosine kinase to protein kinase C via either pathway of phosphatidylinositol 3-kinase or splitting of profilin binding phosphatidylinositol 4,5-bisphosphate. (author)

  4. Role of the nitric oxide/cyclic GMP/Ca2+ signaling pathway in the pyrogenic effect of interleukin-1beta.

    Science.gov (United States)

    Palmi, Mitri; Meini, Antonella

    2002-04-01

    Interleukin-1beta (IL-1beta) has a wide spectrum of inflammatory, metabolic, haemopoietic, and immunological properties. Because it produces fever when injected into animals and humans, it is considered an endogenous pyrogen. There is evidence to suggest that Ca2+ plays a critical role in the central mechanisms of thermoregulation, and in the intracellular signaling pathways controlling fever induced by IL-1beta and other pyrogens. Data from different labs indicate that Ca2+ and Na+ determine the temperature set point in the posterior hypothalamus (PH) of various mammals and that changes in Ca2+ and PGE2 concentrations in the cerebrospinal fluid (CSF) of these animals are associated with IL-1beta-induced fever. Antipyretic drugs such as acetylsalicylic acid, dexamethasone, and lipocortin 5-(204-212) peptide counteract IL-1beta-induced fever and abolish changes in Ca2+ and PGE2 concentrations in CSF. In vitro studies have established that activation of the nitric oxide (NO)/cyclic GMP (cGMP) pathway is part of the signaling cascade transducing Ca2+ mobilization in response to IL-1beta and that the ryanodine (RY)- and inositol-(1,4,5)-trisphosphate (IP3)-sensitive pools are the main source of the mobilized Ca2+. It is concluded that the NO/cGMP/Ca2+ pathway is part of the signaling cascade subserving some of the multiple functions of IL-1beta.

  5. Method of signal analysis

    International Nuclear Information System (INIS)

    Berthomier, Charles

    1975-01-01

    A method capable of handling the amplitude and the frequency time laws of a certain kind of geophysical signals is described here. This method is based upon the analytical signal idea of Gabor and Ville, which is constructed either in the time domain by adding an imaginary part to the real signal (in-quadrature signal), or in the frequency domain by suppressing negative frequency components. The instantaneous frequency of the initial signal is then defined as the time derivative of the phase of the analytical signal, and his amplitude, or envelope, as the modulus of this complex signal. The method is applied to three types of magnetospheric signals: chorus, whistlers and pearls. The results obtained by analog and numerical calculations are compared to results obtained by classical systems using filters, i.e. based upon a different definition of the concept of frequency. The precision with which the frequency-time laws are determined leads then to the examination of the principle of the method and to a definition of instantaneous power density spectrum attached to the signal, and to the first consequences of this definition. In this way, a two-dimensional representation of the signal is introduced which is less deformed by the analysis system properties than the usual representation, and which moreover has the advantage of being obtainable practically in real time [fr

  6. Measurand transient signal suppressor

    Science.gov (United States)

    Bozeman, Richard J., Jr. (Inventor)

    1994-01-01

    A transient signal suppressor for use in a controls system which is adapted to respond to a change in a physical parameter whenever it crosses a predetermined threshold value in a selected direction of increasing or decreasing values with respect to the threshold value and is sustained for a selected discrete time interval is presented. The suppressor includes a sensor transducer for sensing the physical parameter and generating an electrical input signal whenever the sensed physical parameter crosses the threshold level in the selected direction. A manually operated switch is provided for adapting the suppressor to produce an output drive signal whenever the physical parameter crosses the threshold value in the selected direction of increasing or decreasing values. A time delay circuit is selectively adjustable for suppressing the transducer input signal for a preselected one of a plurality of available discrete suppression time and producing an output signal only if the input signal is sustained for a time greater than the selected suppression time. An electronic gate is coupled to receive the transducer input signal and the timer output signal and produce an output drive signal for energizing a control relay whenever the transducer input is a non-transient signal which is sustained beyond the selected time interval.

  7. Ca 2+ signaling by plant Arabidopsis thaliana Pep peptides depends on AtPepR1, a receptor with guanylyl cyclase activity, and cGMP-activated Ca 2+ channels

    KAUST Repository

    Qia, Zhi; Verma, Rajeev K.; Gehring, Christoph A; Yamaguchi, Yube; Zhao, Yichen; Ryan, Clarence A.; Berkowitz, Gerald A.

    2010-01-01

    receptor- like kinase receptor AtPepR1 has guanylyl cyclase activity, generating cGMP from GTP, and that cGMP can activate CNGC2- dependent cytosolic Ca 2+ elevation. AtPep-dependent expression of pathogen-defense genes (PDF1.2, MPK3, and WRKY33

  8. Plant Hormone Homeostasis, Signaling, and Function during Adventitious Root Formation in Cuttings.

    Science.gov (United States)

    Druege, Uwe; Franken, Philipp; Hajirezaei, Mohammad R

    2016-01-01

    Adventitious root (AR) formation in cuttings is a multiphase developmental process, resulting from wounding at the cutting site and isolation from the resource and signal network of the whole plant. Though, promotive effects of auxins are widely used for clonal plant propagation, the regulation and function of plant hormones and their intricate signaling networks during AR formation in cuttings are poorly understood. In this focused review, we discuss our recent publications on the involvement of polar auxin transport (PAT) and transcriptional regulation of auxin and ethylene action during AR formation in petunia cuttings in a broad context. Integrating new findings on cuttings of other plant species and general models on plant hormone networks, a model on the regulation and function of auxin, ethylene, and jasmonate in AR formation of cuttings is presented. PAT and cutting off from the basipetal auxin drain are considered as initial principles generating early accumulation of IAA in the rooting zone. This is expected to trigger a self-regulatory process of auxin canalization and maximization to responding target cells, there inducing the program of AR formation. Regulation of auxin homeostasis via auxin influx and efflux carriers, GH3 proteins and peroxidases, of flavonoid metabolism, and of auxin signaling via AUX/IAA proteins, TOPLESS, ARFs, and SAUR-like proteins are postulated as key processes determining the different phases of AR formation. NO and H2O2 mediate auxin signaling via the cGMP and MAPK cascades. Transcription factors of the GRAS-, AP2/ERF-, and WOX-families link auxin signaling to cell fate specification. Cyclin-mediated governing of the cell cycle, modifications of sugar metabolism and microtubule and cell wall remodeling are considered as important implementation processes of auxin function. Induced by the initial wounding and other abiotic stress factors, up-regulation of ethylene biosynthesis, and signaling via ERFs and early accumulation of

  9. Plant hormone homeostasis, signaling and function during adventitious root formation in cuttings

    Directory of Open Access Journals (Sweden)

    Uwe eDruege

    2016-03-01

    Full Text Available Adventitious root (AR formation in cuttings is a multiphase developmental process, resulting from wounding at the cutting site and isolation from the resource and signal network of the whole plant. Though promotive effects of auxins are widely used for clonal plant propagation, the regulation and function of plant hormones and their intricate signaling networks during AR formation in cuttings are poorly understood. In this focused review, we discuss our recent publications on the involvement of polar auxin transport (PAT and transcriptional regulation of auxin and ethylene action during AR formation in petunia cuttings in a broad context. Integrating new findings on cuttings of other plant species and general models on plant hormone networks, a model on the regulation and function of auxin, ethylene and jasmonate in AR formation of cuttings is presented. PAT and cutting off from the basipetal auxin drain are considered as initial principles generating early accumulation of IAA in the rooting zone. This is expected to trigger a self-regulatory process of auxin canalization and maximization to responding target cells, there inducing the program of AR formation. Regulation of auxin homeostasis via auxin influx and efflux carriers, GH3 proteins and peroxidases, of flavonoid metabolism and of auxin signaling via AUX/IAA proteins, TOPLESS, ARFs and SAUR-like proteins are postulated as key processes determining the different phases of AR formation. NO and H2O2 mediate auxin signaling via the cGMP and MAPK cascades. Transcription factors of the GRAS-, AP2/ERF- and WOX-families link auxin signaling to cell fate specification. Cyclin-mediated governing of the cell cycle, modifications of sugar metabolism and microtubule and cell wall remodeling are considered as important implementation processes of auxin function. Induced by the initial wounding and other abiotic stress factors, up-regulation of ethylene biosynthesis and signaling via ERFs and early

  10. Wnt signaling in cancer

    Science.gov (United States)

    Zhan, T; Rindtorff, N; Boutros, M

    2017-01-01

    Wnt signaling is one of the key cascades regulating development and stemness, and has also been tightly associated with cancer. The role of Wnt signaling in carcinogenesis has most prominently been described for colorectal cancer, but aberrant Wnt signaling is observed in many more cancer entities. Here, we review current insights into novel components of Wnt pathways and describe their impact on cancer development. Furthermore, we highlight expanding functions of Wnt signaling for both solid and liquid tumors. We also describe current findings how Wnt signaling affects maintenance of cancer stem cells, metastasis and immune control. Finally, we provide an overview of current strategies to antagonize Wnt signaling in cancer and challenges that are associated with such approaches. PMID:27617575

  11. Cooperative ethylene receptor signaling

    OpenAIRE

    Liu, Qian; Wen, Chi-Kuang

    2012-01-01

    The gaseous plant hormone ethylene is perceived by a family of five ethylene receptor members in the dicotyledonous model plant Arabidopsis. Genetic and biochemical studies suggest that the ethylene response is suppressed by ethylene receptor complexes, but the biochemical nature of the receptor signal is unknown. Without appropriate biochemical measures to trace the ethylene receptor signal and quantify the signal strength, the biological significance of the modulation of ethylene responses ...

  12. Traffic signal synchronization.

    Science.gov (United States)

    Huang, Ding-wei; Huang, Wei-neng

    2003-05-01

    The benefits of traffic signal synchronization are examined within the cellular automata approach. The microsimulations of traffic flow are obtained with different settings of signal period T and time delay delta. Both numerical results and analytical approximations are presented. For undersaturated traffic, the green-light wave solutions can be realized. For saturated traffic, the correlation among the traffic signals has no effect on the throughput. For oversaturated traffic, the benefits of synchronization are manifest only when stochastic noise is suppressed.

  13. Digital signal processing the Tevatron BPM signals

    International Nuclear Information System (INIS)

    Cancelo, G.; James, E.; Wolbers, S.

    2005-01-01

    The Beam Position Monitor (TeV BPM) readout system at Fermilab's Tevatron has been updated and is currently being commissioned. The new BPMs use new analog and digital hardware to achieve better beam position measurement resolution. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton measurements. The signals provided by the two ends of the BPM pickups are processed by analog band-pass filters and sampled by 14-bit ADCs at 74.3MHz. A crucial part of this work has been the design of digital filters that process the signal. This paper describes the digital processing and estimation techniques used to optimize the beam position measurement. The BPM electronics must operate in narrow-band and wide-band modes to enable measurements of closed-orbit and turn-by-turn positions. The filtering and timing conditions of the signals are tuned accordingly for the operational modes. The analysis and the optimized result for each mode are presented

  14. Nichtkontinuierliche (zeitdiskrete) Signale

    Science.gov (United States)

    Plaßmann, Wilfried

    Zeitdiskrete Signale werden häufig aus zeitkontinuierlichen Signalen durch Abtastung erzeugt. Dass beide Signale gleichwertig sind, zeigt das Abtasttheorem (Kap. 116) von Shannon, sofern die Bedingung nach (116.2), f_{ab}≈(2{,}2 {\\ldots} 4)\\cdot fg) eingehalten wird. Digitale Signale haben Vorteile: Einfache Speicherung, Weiterverarbeitung in Rechnern, wenig störanfällige Übertragung. Für die Bearbeitung dieser Signale dienen die im Kapitel dargestellten Hilfsmittel: Diskrete Fouriertransformation; Schnelle Fouriertransformation; z-Transformation: Darstellung, Sätze zur z-Transformation, Korrespondenzen zu Zeitfunktionen, Beispiele.

  15. Biomedical signals and systems

    CERN Document Server

    Tranquillo, Joseph V

    2013-01-01

    Biomedical Signals and Systems is meant to accompany a one-semester undergraduate signals and systems course. It may also serve as a quick-start for graduate students or faculty interested in how signals and systems techniques can be applied to living systems. The biological nature of the examples allows for systems thinking to be applied to electrical, mechanical, fluid, chemical, thermal and even optical systems. Each chapter focuses on a topic from classic signals and systems theory: System block diagrams, mathematical models, transforms, stability, feedback, system response, control, time

  16. Radiation signal processing system

    International Nuclear Information System (INIS)

    Bennett, M.; Knoll, G.; Strange, D.

    1980-01-01

    An improved signal processing system for radiation imaging apparatus comprises: a radiation transducer producing transducer signals proportional to apparent spatial coordinates of detected radiation events; means for storing true spatial coordinates corresponding to a plurality of predetermined apparent spatial coordinates relative to selected detected radiation events said means for storing responsive to said transducer signal and producing an output signal representative of said true spatial coordinates; and means for interpolating the true spatial coordinates of the detected radiation events located intermediate the stored true spatial coordinates, said means for interpolating communicating with said means for storing

  17. Digital signal processing

    CERN Document Server

    O'Shea, Peter; Hussain, Zahir M

    2011-01-01

    In three parts, this book contributes to the advancement of engineering education and that serves as a general reference on digital signal processing. Part I presents the basics of analog and digital signals and systems in the time and frequency domain. It covers the core topics: convolution, transforms, filters, and random signal analysis. It also treats important applications including signal detection in noise, radar range estimation for airborne targets, binary communication systems, channel estimation, banking and financial applications, and audio effects production. Part II considers sel

  18. Protein kinase N2 regulates AMP kinase signaling and insulin responsiveness of glucose metabolism in skeletal muscle.

    Science.gov (United States)

    Ruby, Maxwell A; Riedl, Isabelle; Massart, Julie; Åhlin, Marcus; Zierath, Juleen R

    2017-10-01

    Insulin resistance is central to the development of type 2 diabetes and related metabolic disorders. Because skeletal muscle is responsible for the majority of whole body insulin-stimulated glucose uptake, regulation of glucose metabolism in this tissue is of particular importance. Although Rho GTPases and many of their affecters influence skeletal muscle metabolism, there is a paucity of information on the protein kinase N (PKN) family of serine/threonine protein kinases. We investigated the impact of PKN2 on insulin signaling and glucose metabolism in primary human skeletal muscle cells in vitro and mouse tibialis anterior muscle in vivo. PKN2 knockdown in vitro decreased insulin-stimulated glucose uptake, incorporation into glycogen, and oxidation. PKN2 siRNA increased 5'-adenosine monophosphate-activated protein kinase (AMPK) signaling while stimulating fatty acid oxidation and incorporation into triglycerides and decreasing protein synthesis. At the transcriptional level, PKN2 knockdown increased expression of PGC-1α and SREBP-1c and their target genes. In mature skeletal muscle, in vivo PKN2 knockdown decreased glucose uptake and increased AMPK phosphorylation. Thus, PKN2 alters key signaling pathways and transcriptional networks to regulate glucose and lipid metabolism. Identification of PKN2 as a novel regulator of insulin and AMPK signaling may provide an avenue for manipulation of skeletal muscle metabolism. Copyright © 2017 the American Physiological Society.

  19. Electromagnetic Field Devices and Their Effects on Nociception and Peripheral Inflammatory Pain Mechanisms.

    Science.gov (United States)

    Ross, Christina L; Teli, Thaleia; Harrison, Benjamin S

    2016-03-01

    Context • During cell-communication processes, endogenous and exogenous signaling affects normal and pathological developmental conditions. Exogenous influences, such as extra-low-frequency (ELF) electromagnetic fields (EMFs) have been shown to affect pain and inflammation by modulating G-protein coupling receptors (GPCRs), downregulating cyclooxygenase-2 (Cox-2) activity, and downregulating inflammatory modulators, such as tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) as well as the transcription factor nuclear factor kappa B (NF-κB). EMF devices could help clinicians who seek an alternative or complementary treatment for relief of patients chronic pain and disability. Objective • The research team intended to review the literature on the effects of EMFs on inflammatory pain mechanisms. Design • We used a literature search of articles published in PubMed using the following key words: low-frequency electromagnetic field therapy, inflammatory pain markers, cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), opioid receptors, G-protein coupling receptors, and enzymes. Setting • The study took place at the Wake Forest School of Medicine in Winston-Salem, NC, USA. Results • The mechanistic pathway most often considered for the biological effects of EMF is the plasma membrane, across which the EMF signal induces a voltage change. Oscillating EMF exerts forces on free ions that are present on both sides of the plasma membrane and that move across the cell surface through transmembrane proteins. The ions create a forced intracellular vibration that is responsible for phenomena such as the influx of extracellular calcium (Ca2+) and the binding affinity of calmodulin (CaM), which is the primary transduction pathway to the secondary messengers, cAMP and cGMP, which have been found to influence inflammatory pain. Conclusions • An emerging body of evidence indicates the existence of a frequency

  20. Calcium-sensing receptor (CaSR): pharmacological properties and signaling pathways.

    Science.gov (United States)

    Conigrave, Arthur D; Ward, Donald T

    2013-06-01

    In this article we consider the mechanisms by which the calcium-sensing receptor (CaSR) induces its cellular responses via the control (activation or inhibition) of signaling pathways. We consider key features of CaSR-mediated signaling including its control of the heterotrimeric G-proteins Gq/11, Gi/o and G12/13 and the downstream consequences recognizing that very few CaSR-mediated cell phenomena have been fully described. We also consider the manner in which the CaSR contributes to the formation of specific signaling scaffolds via peptide recognition sequences in its intracellular C-terminal along with the origins of its high level of cooperativity, particularly for Ca(2+)o, and its remarkable resistance to desensitization. We also consider the nature of the mechanisms by which the CaSR controls oscillatory and sustained Ca(2+)i mobilizing responses and inhibits or elevates cyclic adenosine monophosphate (cAMP) levels dependent on the cellular and signaling context. Finally, we consider the diversity of the receptor's ligands, ligand binding sites and broader compartment-dependent physiological roles leading to the identification of pronounced ligand-biased signaling for agonists including Sr(2+) and modulators including l-amino acids and the clinically effective calcimimetic cinacalcet. We note the implications of these findings for the development of new designer drugs that might target the CaSR in pathophysiological contexts beyond those established for the treatment of disorders of calcium metabolism. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. High density and ligand affinity confer ultrasensitive signal detection by a guanylyl cyclase chemoreceptor

    Science.gov (United States)

    Pichlo, Magdalena; Bungert-Plümke, Stefanie; Weyand, Ingo; Seifert, Reinhard; Bönigk, Wolfgang; Strünker, Timo; Kashikar, Nachiket Dilip; Goodwin, Normann; Müller, Astrid; Körschen, Heinz G.; Collienne, Ursel; Pelzer, Patric; Van, Qui; Enderlein, Jörg; Klemm, Clementine; Krause, Eberhard; Trötschel, Christian; Poetsch, Ansgar; Kremmer, Elisabeth

    2014-01-01

    Guanylyl cyclases (GCs), which synthesize the messenger cyclic guanosine 3′,5′-monophosphate, control several sensory functions, such as phototransduction, chemosensation, and thermosensation, in many species from worms to mammals. The GC chemoreceptor in sea urchin sperm can decode chemoattractant concentrations with single-molecule sensitivity. The molecular and cellular underpinnings of such ultrasensitivity are not known for any eukaryotic chemoreceptor. In this paper, we show that an exquisitely high density of 3 × 105 GC chemoreceptors and subnanomolar ligand affinity provide a high ligand-capture efficacy and render sperm perfect absorbers. The GC activity is terminated within 150 ms by dephosphorylation steps of the receptor, which provides a means for precise control of the GC lifetime and which reduces “molecule noise.” Compared with other ultrasensitive sensory systems, the 10-fold signal amplification by the GC receptor is surprisingly low. The hallmarks of this signaling mechanism provide a blueprint for chemical sensing in small compartments, such as olfactory cilia, insect antennae, or even synaptic boutons. PMID:25135936

  2. Adenyl cyclases and cAMP in plant signaling - Past and present

    KAUST Repository

    Gehring, Christoph A.

    2010-06-25

    In lower eukaryotes and animals 3\\'-5\\'-cyclic adenosine monophosphate (cAMP) and adenyl cyclases (ACs), enzymes that catalyse the formation of cAMP from ATP, have long been established as key components and second messengers in many signaling pathways. In contrast, in plants, both the presence and biological role of cAMP have been a matter of ongoing debate and some controversy. Here we shall focus firstly on the discovery of cellular cAMP in plants and evidence for a role of this second messenger in plant signal transduction. Secondly, we shall review current evidence of plant ACs, analyse aspects of their domain organisations and the biological roles of candidate molecules. In addition, we shall assess different approaches based on search motifs consisting of functionally assigned amino acids in the catalytic centre of annotated and/or experimentally tested nucleotide cyclases that can contribute to the identification of novel candidate molecules with AC activity such as F-box and TIR proteins. 2010 Gehring; licensee BioMed Central Ltd.

  3. Adenyl cyclases and cAMP in plant signaling - Past and present

    KAUST Repository

    Gehring, Christoph A

    2010-01-01

    In lower eukaryotes and animals 3'-5'-cyclic adenosine monophosphate (cAMP) and adenyl cyclases (ACs), enzymes that catalyse the formation of cAMP from ATP, have long been established as key components and second messengers in many signaling pathways. In contrast, in plants, both the presence and biological role of cAMP have been a matter of ongoing debate and some controversy. Here we shall focus firstly on the discovery of cellular cAMP in plants and evidence for a role of this second messenger in plant signal transduction. Secondly, we shall review current evidence of plant ACs, analyse aspects of their domain organisations and the biological roles of candidate molecules. In addition, we shall assess different approaches based on search motifs consisting of functionally assigned amino acids in the catalytic centre of annotated and/or experimentally tested nucleotide cyclases that can contribute to the identification of novel candidate molecules with AC activity such as F-box and TIR proteins. 2010 Gehring; licensee BioMed Central Ltd.

  4. Netrin-1 - DCC Signaling Systems and Age-Related Macular Degeneration.

    Directory of Open Access Journals (Sweden)

    John Paul SanGiovanni

    Full Text Available We conducted a nested candidate gene study and pathway-based enrichment analysis on data from a multi-national 77,000-person project on the molecular genetics of age-related macular degeneration (AMD to identify AMD-associated DNA-sequence variants in genes encoding constituents of a netrin-1 (NTN1-based signaling pathway that converges on DNA-binding transcription complexes through a 3'-5'-cyclic adenosine monophosphate-calcineurin (cAMP-CN-dependent axis. AMD-associated single nucleotide polymorphisms (SNPs existed in 9 linkage disequilibrium-independent genomic regions; these included loci overlapping NTN1 (rs9899630, P ≤ 9.48 x 10(-5, DCC (Deleted in Colorectal Cancer--the gene encoding a primary NTN1 receptor (rs8097127, P ≤ 3.03 x 10(-5, and 6 other netrin-related genes. Analysis of the NTN1-DCC pathway with exact methods demonstrated robust enrichment with AMD-associated SNPs (corrected P-value = 0.038, supporting the idea that processes driven by NTN1-DCC signaling systems operate in advanced AMD. The NTN1-DCC pathway contains targets of FDA-approved drugs and may offer promise for guiding applied clinical research on preventive and therapeutic interventions for AMD.

  5. Drought Signaling in Plants

    Indian Academy of Sciences (India)

    depending upon the source and nature of signaling: (i) hormone signal, (ii) .... plants to regulate the rate of transpiration through minor structural .... cell has to keep spending energy (in the form of A TP) to maintain a .... enzymes and proteins in the regulation of cellular metabolism can be determined by either inactivating.

  6. Ubiquitination in apoptosis signaling

    NARCIS (Netherlands)

    van de Kooij, L.W.

    2014-01-01

    The work described in this thesis focuses on ubiquitination and protein degradation, with an emphasis on how these processes regulate apoptosis signaling. More specifically, our aims were: 1. To increase the understanding of ubiquitin-mediated regulation of apoptosis signaling. 2. To identify the E3

  7. Multiresolution signal decomposition schemes

    NARCIS (Netherlands)

    J. Goutsias (John); H.J.A.M. Heijmans (Henk)

    1998-01-01

    textabstract[PNA-R9810] Interest in multiresolution techniques for signal processing and analysis is increasing steadily. An important instance of such a technique is the so-called pyramid decomposition scheme. This report proposes a general axiomatic pyramid decomposition scheme for signal analysis

  8. SignalR blueprints

    CERN Document Server

    Ingebrigtsen, Einar

    2015-01-01

    This book is designed for software developers, primarily those with knowledge of C#, .NET, and JavaScript. Good knowledge and understanding of SignalR is assumed to allow efficient programming of core elements and applications in SignalR.

  9. Optimal fault signal estimation

    NARCIS (Netherlands)

    Stoorvogel, Antonie Arij; Niemann, H.H.; Saberi, A.; Sannuti, P.

    2002-01-01

    We consider here both fault identification and fault signal estimation. Regarding fault identification, we seek either exact or almost fault identification. On the other hand, regarding fault signal estimation, we seek either $H_2$ optimal, $H_2$ suboptimal or Hinfinity suboptimal estimation. By

  10. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2011-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital

  11. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2010-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital

  12. Bioelectric Signal Measuring System

    Science.gov (United States)

    Guadarrama-Santana, A.; Pólo-Parada, L.; García-Valenzuela, A.

    2015-01-01

    We describe a low noise measuring system based on interdigitated electrodes for sensing bioelectrical signals. The system registers differential voltage measurements in order of microvolts. The base noise during measurements was in nanovolts and thus, the sensing signals presented a very good signal to noise ratio. An excitation voltage of 1Vrms with 10 KHz frequency was applied to an interdigitated capacitive sensor without a material under test and to a mirror device simultaneously. The output signals of both devices was then subtracted in order to obtain an initial reference value near cero volts and reduce parasitic capacitances due to the electronics, wiring and system hardware as well. The response of the measuring system was characterized by monitoring temporal bioelectrical signals in real time of biological materials such as embryo chicken heart cells and bovine suprarenal gland cells.

  13. Acoustic Signals and Systems

    DEFF Research Database (Denmark)

    2008-01-01

    The Handbook of Signal Processing in Acoustics will compile the techniques and applications of signal processing as they are used in the many varied areas of Acoustics. The Handbook will emphasize the interdisciplinary nature of signal processing in acoustics. Each Section of the Handbook...... will present topics on signal processing which are important in a specific area of acoustics. These will be of interest to specialists in these areas because they will be presented from their technical perspective, rather than a generic engineering approach to signal processing. Non-specialists, or specialists...... from different areas, will find the self-contained chapters accessible and will be interested in the similarities and differences between the approaches and techniques used in different areas of acoustics....

  14. Molecular and Cellular Signaling

    CERN Document Server

    Beckerman, Martin

    2005-01-01

    A small number of signaling pathways, no more than a dozen or so, form a control layer that is responsible for all signaling in and between cells of the human body. The signaling proteins belonging to the control layer determine what kinds of cells are made during development and how they function during adult life. Malfunctions in the proteins belonging to the control layer are responsible for a host of human diseases ranging from neurological disorders to cancers. Most drugs target components in the control layer, and difficulties in drug design are intimately related to the architecture of the control layer. Molecular and Cellular Signaling provides an introduction to molecular and cellular signaling in biological systems with an emphasis on the underlying physical principles. The text is aimed at upper-level undergraduates, graduate students and individuals in medicine and pharmacology interested in broadening their understanding of how cells regulate and coordinate their core activities and how diseases ...

  15. Adaptive signal processor

    Energy Technology Data Exchange (ETDEWEB)

    Walz, H.V.

    1980-07-01

    An experimental, general purpose adaptive signal processor system has been developed, utilizing a quantized (clipped) version of the Widrow-Hoff least-mean-square adaptive algorithm developed by Moschner. The system accommodates 64 adaptive weight channels with 8-bit resolution for each weight. Internal weight update arithmetic is performed with 16-bit resolution, and the system error signal is measured with 12-bit resolution. An adapt cycle of adjusting all 64 weight channels is accomplished in 8 ..mu..sec. Hardware of the signal processor utilizes primarily Schottky-TTL type integrated circuits. A prototype system with 24 weight channels has been constructed and tested. This report presents details of the system design and describes basic experiments performed with the prototype signal processor. Finally some system configurations and applications for this adaptive signal processor are discussed.

  16. Adaptive signal processor

    International Nuclear Information System (INIS)

    Walz, H.V.

    1980-07-01

    An experimental, general purpose adaptive signal processor system has been developed, utilizing a quantized (clipped) version of the Widrow-Hoff least-mean-square adaptive algorithm developed by Moschner. The system accommodates 64 adaptive weight channels with 8-bit resolution for each weight. Internal weight update arithmetic is performed with 16-bit resolution, and the system error signal is measured with 12-bit resolution. An adapt cycle of adjusting all 64 weight channels is accomplished in 8 μsec. Hardware of the signal processor utilizes primarily Schottky-TTL type integrated circuits. A prototype system with 24 weight channels has been constructed and tested. This report presents details of the system design and describes basic experiments performed with the prototype signal processor. Finally some system configurations and applications for this adaptive signal processor are discussed

  17. Zinc Signals and Immunity.

    Science.gov (United States)

    Maywald, Martina; Wessels, Inga; Rink, Lothar

    2017-10-24

    Zinc homeostasis is crucial for an adequate function of the immune system. Zinc deficiency as well as zinc excess result in severe disturbances in immune cell numbers and activities, which can result in increased susceptibility to infections and development of especially inflammatory diseases. This review focuses on the role of zinc in regulating intracellular signaling pathways in innate as well as adaptive immune cells. Main underlying molecular mechanisms and targets affected by altered zinc homeostasis, including kinases, caspases, phosphatases, and phosphodiesterases, will be highlighted in this article. In addition, the interplay of zinc homeostasis and the redox metabolism in affecting intracellular signaling will be emphasized. Key signaling pathways will be described in detail for the different cell types of the immune system. In this, effects of fast zinc flux, taking place within a few seconds to minutes will be distinguish from slower types of zinc signals, also designated as "zinc waves", and late homeostatic zinc signals regarding prolonged changes in intracellular zinc.

  18. Age-Related Alterations in the Expression of Genes and Synaptic Plasticity Associated with Nitric Oxide Signaling in the Mouse Dorsal Striatum

    Directory of Open Access Journals (Sweden)

    Aisa N. Chepkova

    2015-01-01

    Full Text Available Age-related alterations in the expression of genes and corticostriatal synaptic plasticity were studied in the dorsal striatum of mice of four age groups from young (2-3 months old to old (18–24 months of age animals. A significant decrease in transcripts encoding neuronal nitric oxide (NO synthase and receptors involved in its activation (NR1 subunit of the glutamate NMDA receptor and D1 dopamine receptor was found in the striatum of old mice using gene array and real-time RT-PCR analysis. The old striatum showed also a significantly higher number of GFAP-expressing astrocytes and an increased expression of astroglial, inflammatory, and oxidative stress markers. Field potential recordings from striatal slices revealed age-related alterations in the magnitude and dynamics of electrically induced long-term depression (LTD and significant enhancement of electrically induced long-term potentiation in the middle-aged striatum (6-7 and 12-13 months of age. Corticostriatal NO-dependent LTD induced by pharmacological activation of group I metabotropic glutamate receptors underwent significant reduction with aging and could be restored by inhibition of cGMP hydrolysis indicating that its age-related deficit is caused by an altered NO-cGMP signaling cascade. It is suggested that age-related alterations in corticostriatal synaptic plasticity may result from functional alterations in receptor-activated signaling cascades associated with increasing neuroinflammation and a prooxidant state.

  19. Orexin/Hypocretin Signaling.

    Science.gov (United States)

    Kukkonen, Jyrki P

    Orexin/hypocretin peptide (orexin-A and orexin-B) signaling is believed to take place via the two G-protein-coupled receptors (GPCRs), named OX 1 and OX 2 orexin receptors, as described in the previous chapters. Signaling of orexin peptides has been investigated in diverse endogenously orexin receptor-expressing cells - mainly neurons but also other types of cells - and in recombinant cells expressing the receptors in a heterologous manner. Findings in the different systems are partially convergent but also indicate cellular background-specific signaling. The general picture suggests an inherently high degree of diversity in orexin receptor signaling.In the current chapter, I present orexin signaling on the cellular and molecular levels. Discussion of the connection to (potential) physiological orexin responses is only brief since these are in focus of other chapters in this book. The same goes for the post-synaptic signaling mechanisms, which are dealt with in Burdakov: Postsynaptic actions of orexin. The current chapter is organized according to the tissue type, starting from the central nervous system. Finally, receptor signaling pathways are discussed across tissues, cell types, and even species.

  20. Modulation of neurotrophic signaling pathways by polyphenols

    Directory of Open Access Journals (Sweden)

    Moosavi F

    2015-12-01

    Full Text Available Fatemeh Moosavi,1,2 Razieh Hosseini,1,2 Luciano Saso,3 Omidreza Firuzi1 1Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; 2Department of Pharmacology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran; 3Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of Rome, Rome, Italy Abstract: Polyphenols are an important class of phytochemicals, and several lines of evidence have demonstrated their beneficial effects in the context of a number of pathologies including neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease. In this report, we review the studies on the effects of polyphenols on neuronal survival, growth, proliferation and differentiation, and the signaling pathways involved in these neurotrophic actions. Several polyphenols including flavonoids such as baicalein, daidzein, luteolin, and nobiletin as well as nonflavonoid polyphenols such as auraptene, carnosic acid, curcuminoids, and hydroxycinnamic acid derivatives including caffeic acid phentyl ester enhance neuronal survival and promote neurite outgrowth in vitro, a hallmark of neuronal differentiation. Assessment of underlying mechanisms, especially in PC12 neuronal-like cells, reveals that direct agonistic effect on tropomyosin receptor kinase (Trk receptors, the main receptors of neurotrophic factors including nerve growth factor (NGF and brain-derived neurotrophic factor (BDNF explains the action of few polyphenols such as 7,8-dihydroxyflavone. However, several other polyphenolic compounds activate extracellular signal-regulated kinase (ERK and phosphoinositide 3-kinase (PI3K/Akt pathways. Increased expression of neurotrophic factors in vitro and in vivo is the mechanism of neurotrophic action of flavonoids such as scutellarin, daidzein, genistein, and fisetin, while compounds like apigenin and ferulic acid increase cyclic adenosine monophosphate

  1. Signal flow analysis

    CERN Document Server

    Abrahams, J R; Hiller, N

    1965-01-01

    Signal Flow Analysis provides information pertinent to the fundamental aspects of signal flow analysis. This book discusses the basic theory of signal flow graphs and shows their relation to the usual algebraic equations.Organized into seven chapters, this book begins with an overview of properties of a flow graph. This text then demonstrates how flow graphs can be applied to a wide range of electrical circuits that do not involve amplification. Other chapters deal with the parameters as well as circuit applications of transistors. This book discusses as well the variety of circuits using ther

  2. Lead induces chondrogenesis and alters transforming growth factor-beta and bone morphogenetic protein signaling in mesenchymal cell populations.

    Science.gov (United States)

    Zuscik, Michael J; Ma, Lin; Buckley, Taylor; Puzas, J Edward; Drissi, Hicham; Schwarz, Edward M; O'Keefe, Regis J

    2007-09-01

    It has been established that skeletal growth is stunted in lead-exposed children. Because chondrogenesis is a seminal step during skeletal development, elucidating the impact of Pb on this process is the first step toward understanding the mechanism of Pb toxicity in the skeleton. The aim of this study was to test the hypothesis that Pb alters chondrogenic commitment of mesenchymal cells and to assess the effects of Pb on various signaling pathways. We assessed the influence of Pb on chondrogenesis in murine limb bud mesenchymal cells (MSCs) using nodule formation assays and gene analyses. The effects of Pb on transforming growth factor-beta (TGF-beta) and bone morphogenetic protein (BMP) signaling was studied using luciferase-based reporters and Western analyses, and luciferase-based assays were used to study cyclic adenosine monophosphate response element binding protein (CREB), beta-catenin, AP-1, and nuclear factor-kappa B (NF-kappaB) signaling. We also used an ectopic bone formation assay to determine how Pb affects chondrogenesis in vivo. Pb-exposed MSCs showed enhanced basal and TGF-beta/BMP induction of chondrogenesis, evidenced by enhanced nodule formation and up-regulation of Sox-9, type 2 collagen, and aggrecan, all key markers of chondrogenesis. We observed enhanced chondrogenesis during ectopic bone formation in mice preexposed to Pb via drinking water. In MSCs, Pb enhanced TGF-beta but inhibited BMP-2 signaling, as measured by luciferase reporter assays and Western analyses of Smad phosphorylation. Although Pb had no effect on basal CREB or Wnt/beta-catenin pathway activity, it induced NFkappaB signaling and inhibited AP-1 signaling. The in vitro and in vivo induction of chondrogenesis by Pb likely involves modulation and integration of multiple signaling pathways including TGF-beta, BMP, AP-1, and NFkappaB.

  3. Underwater Acoustic Signal Processing

    National Research Council Canada - National Science Library

    Culver, Richard L; Sibul, Leon H; Bradley, David L

    2007-01-01

    .... The research is directed toward passive sonar detection and classification, continuous wave (CW) and broadband signals, shallow water operation, both platform-mounted and distributed systems, and frequencies below 1 kHz...

  4. Signals and systems

    CERN Document Server

    Rao, K Deergha

    2018-01-01

    This textbook covers the fundamental theories of signals and systems analysis, while incorporating recent developments from integrated circuits technology into its examples. Starting with basic definitions in signal theory, the text explains the properties of continuous-time and discrete-time systems and their representation by differential equations and state space. From those tools, explanations for the processes of Fourier analysis, the Laplace transform, and the z-Transform provide new ways of experimenting with different kinds of time systems. The text also covers the separate classes of analog filters and their uses in signal processing applications. Intended for undergraduate electrical engineering students, chapter sections include exercise for review and practice for the systems concepts of each chapter. Along with exercises, the text includes MATLAB-based examples to allow readers to experiment with signals and systems code on their own. An online repository of the MATLAB code from this textbook can...

  5. Topological signal processing

    CERN Document Server

    Robinson, Michael

    2014-01-01

    Signal processing is the discipline of extracting information from collections of measurements. To be effective, the measurements must be organized and then filtered, detected, or transformed to expose the desired information.  Distortions caused by uncertainty, noise, and clutter degrade the performance of practical signal processing systems. In aggressively uncertain situations, the full truth about an underlying signal cannot be known.  This book develops the theory and practice of signal processing systems for these situations that extract useful, qualitative information using the mathematics of topology -- the study of spaces under continuous transformations.  Since the collection of continuous transformations is large and varied, tools which are topologically-motivated are automatically insensitive to substantial distortion. The target audience comprises practitioners as well as researchers, but the book may also be beneficial for graduate students.

  6. Acoustic MIMO signal processing

    CERN Document Server

    Huang, Yiteng; Chen, Jingdong

    2006-01-01

    A timely and important book addressing a variety of acoustic signal processing problems under multiple-input multiple-output (MIMO) scenarios. It uniquely investigates these problems within a unified framework offering a novel and penetrating analysis.

  7. Ultrahigh bandwidth signal processing

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo

    2016-01-01

    Optical time lenses have proven to be very versatile for advanced optical signal processing. Based on a controlled interplay between dispersion and phase-modulation by e.g. four-wave mixing, the processing is phase-preserving, an hence useful for all types of data signals including coherent multi......-level modulation founats. This has enabled processing of phase-modulated spectrally efficient data signals, such as orthogonal frequency division multiplexed (OFDM) signa In that case, a spectral telescope system was used, using two time lenses with different focal lengths (chirp rates), yielding a spectral...... regeneratio These operations require a broad bandwidth nonlinear platform, and novel photonic integrated nonlinear platform like aluminum gallium arsenide nano-waveguides used for 1.28 Tbaud optical signal processing will be described....

  8. Traffic Signal Cycle Lengths

    Data.gov (United States)

    Town of Chapel Hill, North Carolina — Traffic signal location list for the town of Chapel Hill. This data set includes light cycle information as well as as intersection information.The Town of Chapel...

  9. Foundations of signal processing

    CERN Document Server

    Vetterli, Martin; Goyal, Vivek K

    2014-01-01

    This comprehensive and engaging textbook introduces the basic principles and techniques of signal processing, from the fundamental ideas of signals and systems theory to real-world applications. Students are introduced to the powerful foundations of modern signal processing, including the basic geometry of Hilbert space, the mathematics of Fourier transforms, and essentials of sampling, interpolation, approximation and compression. The authors discuss real-world issues and hurdles to using these tools, and ways of adapting them to overcome problems of finiteness and localisation, the limitations of uncertainty and computational costs. Standard engineering notation is used throughout, making mathematical examples easy for students to follow, understand and apply. It includes over 150 homework problems and over 180 worked examples, specifically designed to test and expand students' understanding of the fundamentals of signal processing, and is accompanied by extensive online materials designed to aid learning, ...

  10. G Protein-Linked Signaling Pathways in Bipolar and Major Depressive Disorders

    Directory of Open Access Journals (Sweden)

    Hiroaki eTomita

    2013-12-01

    Full Text Available The G-protein linked signaling system (GPLS comprises a large number of G-proteins, G protein-coupled receptors (GPCRs, GPCR ligands, and downstream effector molecules. G-proteins interact with both GPCRs and downstream effectors such as cyclic adenosine monophosphate (cAMP, phosphatidylinositols, and ion channels. The GPLS is implicated in the pathophysiology and pharmacology of both major depressive disorder (MDD and bipolar disorder (BPD. This study evaluated whether GPLS is altered at the transcript level. The gene expression in the dorsolateral prefrontal (DLPFC and anterior cingulate (ACC were compared from MDD, BPD, and control subjects using Affymetrix Gene Chips and real time quantitative PCR. High quality brain tissue was used in the study to control for confounding effects of agonal events, tissue pH, RNA integrity, gender, and age. GPLS signaling transcripts were altered especially in the ACC of BPD and MDD subjects. Transcript levels of molecules which repress cAMP activity were increased in BPD and decreased in MDD. Two orphan GPCRs, GPRC5B and GPR37, showed significantly decreased expression levels in MDD, and significantly increased expression levels in BPD. Our results suggest opposite changes in BPD and MDD in the GPLS, ‘activated’ cAMP signaling activity in BPD and ‘blunted’ cAMP signaling activity in MDD. GPRC5B and GPR37 both appear to have behavioral effects, and are also candidate genes for neurodegenerative disorders. In the context of the opposite changes observed in BPD and MDD, these GPCRs warrant further study of their brain effects.

  11. Insulin signaling in various equine tissues under basal conditions and acute stimulation by intravenously injected insulin.

    Science.gov (United States)

    Warnken, Tobias; Brehm, Ralph; Feige, Karsten; Huber, Korinna

    2017-10-01

    The aim of the study was to analyze key proteins of the equine insulin signaling cascade and their extent of phosphorylation in biopsies from muscle tissue (MT), liver tissue (LT), and nuchal AT, subcutaneous AT, and retroperitoneal adipose tissues. This was investigated under unstimulated (B1) and intravenously insulin stimulated (B2) conditions, which were achieved by injection of insulin (0.1 IU/kg bodyweight) and glucose (150 mg/kg bodyweight). Twelve warmblood horses aged 15 ± 6.8 yr (yr), weighing 559 ± 79 kg, and with a mean body condition score of 4.7 ± 1.5 were included in the study. Key proteins of the insulin signaling cascade were semiquantitatively determined using Western blotting. Furthermore, modulation of the cascade was assessed. The basal expression of the proteins was only slightly influenced during the experimental period. Insulin induced a high extent of phosphorylation of insulin receptor in LT (P < 0.01) but not in MT. Protein kinase B and mechanistic target of rapamycin expressed a higher extent of phosphorylation in all tissues in B2 biopsies. Adenosine monophosphate protein kinase, as a component related to insulin signaling, expressed enhanced phosphorylation in MT (P < 0.05) and adipose tissues (nuchal AT P < 0.05; SCAT P < 0.01; retroperitoneal adipose tissue P < 0.05), but not in LT at B2. Tissue-specific variations in the acute response of insulin signaling to intravenously injected insulin were observed. In conclusion, insulin sensitivity in healthy horses is based on a complex concerted action of different tissues by their variations in the molecular response to insulin. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Source of seismic signals

    Energy Technology Data Exchange (ETDEWEB)

    Frankovskii, B.A.; Khor' yakov, K.A.

    1980-08-30

    Patented is a source of seismic signals consisting of a shock generator with a basic low-voltage and auxillary high-voltage stator coils, a capacitive transformer and control switches. To increase the amplitude of signal excitation a condensor battery and auxillary commutator are introduced into the device, which are connected in parallel and serially into the circuit of the main low-voltage stator coil.

  13. Redox signaling in plants.

    Science.gov (United States)

    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.

  14. Supplementation of chitosan alleviates high-fat diet-enhanced lipogenesis in rats via adenosine monophosphate (AMP)-activated protein kinase activation and inhibition of lipogenesis-associated genes.

    Science.gov (United States)

    Chiu, Chen-Yuan; Chan, Im-Lam; Yang, Tsung-Han; Liu, Shing-Hwa; Chiang, Meng-Tsan

    2015-03-25

    This study investigated the role of chitosan in lipogenesis in high-fat diet-induced obese rats. The lipogenesis-associated genes and their upstream regulatory proteins were explored. Diet supplementation of chitosan efficiently decreased the increased weights in body, livers, and adipose tissues in high-fat diet-fed rats. Chitosan supplementation significantly raised the lipolysis rate; attenuated the adipocyte hypertrophy, triglyceride accumulation, and lipoprotein lipase activity in epididymal adipose tissues; and decreased hepatic enzyme activities of lipid biosynthesis. Chitosan supplementation significantly activated adenosine monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation and attenuated high-fat diet-induced protein expressions of lipogenic transcription factors (PPAR-γ and SREBP1c) in livers and adipose tissues. Moreover, chitosan supplementation significantly inhibited the expressions of downstream lipogenic genes (FAS, HMGCR, FATP1, and FABP4) in livers and adipose tissues of high-fat diet-fed rats. These results demonstrate for the first time that chitosan supplementation alleviates high-fat diet-enhanced lipogenesis in rats via AMPK activation and lipogenesis-associated gene inhibition.

  15. The fruit of Acanthopanax senticosus (Rupr. et Maxim.) Harms improves insulin resistance and hepatic lipid accumulation by modulation of liver adenosine monophosphate-activated protein kinase activity and lipogenic gene expression in high-fat diet-fed obese mice.

    Science.gov (United States)

    Saito, Tetsuo; Nishida, Miyako; Saito, Masafumi; Tanabe, Akari; Eitsuka, Takahiro; Yuan, Shi-Hua; Ikekawa, Nobuo; Nishida, Hiroshi

    2016-10-01

    Obesity-associated insulin resistance is a major risk factor for most metabolic diseases, including dyslipidemia and type 2 diabetes. Acanthopanax senticosus (Rupr. et Maxim.) Harms (Goka) root has been used in traditional Chinese medicine for treatment of diabetes and other conditions; however, little is known about the effects of Goka fruit (GF). Goka fruit is rich in anthocyanin, which has beneficial effects on obesity and insulin resistance via activation of adenosine monophosphate-activated protein kinase (AMPK). We hypothesized that GF can improve obesity-associated insulin resistance. The aim of the present study was to investigate whether GF improves insulin resistance in high-fat diet (HFD)-induced obese mice. High-fat diet mice treated with GF (500 and 1000 mg/kg) for 12 weeks showed an improved glucose tolerance and insulin sensitivity, as well as reduced plasma insulin and liver lipid accumulation. Moreover, GF administration to HFD mice resulted in down-regulation of fatty acid synthase expression and up-regulation of cholesterol 7-alpha-hydroxylase expression in the liver. Notably, AMPK phosphorylation in the liver increased after GF administration. In summary, GF supplementation improved obesity-associated insulin resistance and hepatic lipid accumulation through modulation of AMPK activity and lipid metabolism-associated gene expression. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. 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.

  17. Digital Signal Processing applied to Physical Signals

    CERN Document Server

    Alberto, Diego; Musa, L

    2011-01-01

    It is well known that many of the scientific and technological discoveries of the XXI century will depend on the capability of processing and understanding a huge quantity of data. With the advent of the digital era, a fully digital and automated treatment can be designed and performed. From data mining to data compression, from signal elaboration to noise reduction, a processing is essential to manage and enhance features of interest after every data acquisition (DAQ) session. In the near future, science will go towards interdisciplinary research. In this work there will be given an example of the application of signal processing to different fields of Physics from nuclear particle detectors to biomedical examinations. In Chapter 1 a brief description of the collaborations that allowed this thesis is given, together with a list of the publications co-produced by the author in these three years. The most important notations, definitions and acronyms used in the work are also provided. In Chapter 2, the last r...

  18. Inhibition of Cyclic Adenosine Monophosphate (cAMP-response Element-binding Protein (CREB-binding Protein (CBP/β-Catenin Reduces Liver Fibrosis in Mice

    Directory of Open Access Journals (Sweden)

    Yosuke Osawa

    2015-11-01

    Full Text Available Wnt/β-catenin is involved in every aspect of embryonic development and in the pathogenesis of many human diseases, and is also implicated in organ fibrosis. However, the role of β-catenin-mediated signaling on liver fibrosis remains unclear. To explore this issue, the effects of PRI-724, a selective inhibitor of the cAMP-response element-binding protein-binding protein (CBP/β-catenin interaction, on liver fibrosis were examined using carbon tetrachloride (CCl4- or bile duct ligation (BDL-induced mouse liver fibrosis models. Following repetitive CCl4 administrations, the nuclear translocation of β-catenin was observed only in the non-parenchymal cells in the liver. PRI-724 treatment reduced the fibrosis induced by CCl4 or BDL. C-82, an active form of PRI-724, inhibited the activation of isolated primary mouse quiescent hepatic stellate cells (HSCs and promoted cell death in culture-activated HSCs. During the fibrosis resolution period, an increase in F4/80+ CD11b+ and Ly6Clow CD11b+ macrophages was induced by CCl4 and was sustained for two weeks thereafter, even after having stopped CCl4 treatment. PRI-724 accelerated the resolution of CCl4-induced liver fibrosis, and this was accompanied by increased matrix metalloproteinase (MMP-9, MMP-2, and MMP-8 expression in intrahepatic leukocytes. In conclusion, targeting the CBP/β-catenin interaction may become a new therapeutic strategy in treating liver fibrosis.

  19. Cellular signalling properties in microcircuits

    DEFF Research Database (Denmark)

    Toledo-Rodriguez, Maria; El Manira, Abdeljabbar; Wallén, Peter

    2005-01-01

    Molecules and cells are the signalling elements in microcircuits. Recent studies have uncovered bewildering diversity in postsynaptic signalling properties in all areas of the vertebrate nervous system. Major effort is now being invested in establishing the specialized signalling properties...

  20. VLSI signal processing technology

    CERN Document Server

    Swartzlander, Earl

    1994-01-01

    This book is the first in a set of forthcoming books focussed on state-of-the-art development in the VLSI Signal Processing area. It is a response to the tremendous research activities taking place in that field. These activities have been driven by two factors: the dramatic increase in demand for high speed signal processing, especially in consumer elec­ tronics, and the evolving microelectronic technologies. The available technology has always been one of the main factors in determining al­ gorithms, architectures, and design strategies to be followed. With every new technology, signal processing systems go through many changes in concepts, design methods, and implementation. The goal of this book is to introduce the reader to the main features of VLSI Signal Processing and the ongoing developments in this area. The focus of this book is on: • Current developments in Digital Signal Processing (DSP) pro­ cessors and architectures - several examples and case studies of existing DSP chips are discussed in...

  1. Signal integrity characterization techniques

    CERN Document Server

    Bogatin, Eric

    2009-01-01

    "Signal Integrity Characterization Techniques" addresses the gap between traditional digital and microwave curricula all while focusing on a practical and intuitive understanding of signal integrity effects within the data transmission channel. High-speed interconnects such as connectors, PCBs, cables, IC packages, and backplanes are critical elements of differential channels that must be designed using today's most powerful analysis and characterization tools.Both measurements and simulation must be done on the device under test, and both activities must yield data that correlates with each other. Most of this book focuses on real-world applications of signal integrity measurements - from backplane for design challenges to error correction techniques to jitter measurement technologies. The authors' approach wisely addresses some of these new high-speed technologies, and it also provides valuable insight into its future direction and will teach the reader valuable lessons on the industry.

  2. Quantum signaling game

    International Nuclear Information System (INIS)

    Frackiewicz, Piotr

    2014-01-01

    We present a quantum approach to a signaling game; a special kind of extensive game of incomplete information. Our model is based on quantum schemes for games in strategic form where players perform unitary operators on their own qubits of some fixed initial state and the payoff function is given by a measurement on the resulting final state. We show that the quantum game induced by our scheme coincides with a signaling game as a special case and outputs nonclassical results in general. As an example, we consider a quantum extension of the signaling game in which the chance move is a three-parameter unitary operator whereas the players' actions are equivalent to classical ones. In this case, we study the game in terms of Nash equilibria and refine the pure Nash equilibria adapting to the quantum game the notion of a weak perfect Bayesian equilibrium. (paper)

  3. PKD signaling and pancreatitis

    Science.gov (United States)

    Yuan, Jingzhen; Pandol, Stephen J.

    2016-01-01

    Background Acute pancreatitis is a serious medical disorder with no current therapies directed to the molecular pathogenesis of the disorder. Inflammation, inappropriate intracellular activation of digestive enzymes, and parenchymal acinar cell death by necrosis are the critical pathophysiologic processes of acute pancreatitis. Thus, it is necessary to elucidate the key molecular signals that mediate these pathobiologic processes and develop new therapeutic strategies to attenuate the appropriate signaling pathways in order to improve outcomes for this disease. A novel serine/threonine protein kinase D (PKD) family has emerged as key participants in signal transduction, and this family is increasingly being implicated in the regulation of multiple cellular functions and diseases. Methods This review summarizes recent findings of our group and others regarding the signaling pathway and the biological roles of the PKD family in pancreatic acinar cells. In particular, we highlight our studies of the functions of PKD in several key pathobiologic processes associated with acute pancreatitis in experimental models. Results Our findings reveal that PKD signaling is required for NF-κB activation/inflammation, intracellular zymogen activation, and acinar cell necrosis in rodent experimental pancreatitis. Novel small-molecule PKD inhibitors attenuate the severity of pancreatitis in both in vitro and in vivo experimental models. Further, this review emphasizes our latest advances in the therapeutic application of PKD inhibitors to experimental pancreatitis after the initiation of pancreatitis. Conclusions These novel findings suggest that PKD signaling is a necessary modulator in key initiating pathobiologic processes of pancreatitis, and that it constitutes a novel therapeutic target for treatments of this disorder. PMID:26879861

  4. Cellular chromophores and signaling in low level light therapy

    Science.gov (United States)

    Hamblin, Michael R.; Demidova-Rice, Tatiana N.

    2007-02-01

    particular, signaling cascades are initiated via cyclic adenosine monophosphate (cAMP) and nuclear factor kappa B (NF-κB). These signal transduction pathways in turn lead to increased cell proliferation and migration (particularly by fibroblasts), modulation in levels of cytokines, growth factors and inflammatory mediators, and increases in anti-apoptotic proteins. The results of these biochemical and cellular changes in animals and patients include such benefits as increased healing in chronic wounds, improvements in sports injuries and carpal tunnel syndrome, pain reduction in arthritis and neuropathies, and amelioration of damage after heart attacks, stroke, nerve injury and retinal toxicity.

  5. Thyroid hormone activates rat liver adenosine 5,-monophosphate-activated protein kinase: relation to CaMKKb, TAK1 and LKB1 expression and energy status.

    Science.gov (United States)

    Vargas, R; Ortega, Y; Bozo, V; Andrade, M; Minuzzi, G; Cornejo, P; Fernandez, V; Videla, L A

    2013-01-01

    AMP-activated protein kinase (AMPK) is a sensor of energy status supporting cellular energy homeostasis that may represent the metabolic basis for 3,3,,5-triiodo-L-thyronine (T3) liver preconditioning. Functionally transient hyperthyroid state induced by T3 (single dose of 0.1 mg/kg) in fed rats led to upregulation of mRNA expression (RT-PCR) and protein phosphorylation (Western blot) of hepatic AMPK at 8 to 36 h after treatment. AMPK Thr 172 phosphorylation induced by T3 is associated with enhanced mRNA expression of the upstream kinases Ca2+ -calmodulin-dependent protein kinase kinase-beta (CaMKKbeta) and transforming growth-factor-beta-activated kinase-1 (TAK1), with increased protein levels of CaMKKbeta and higher TAK1 phosphorylation, without changes in those of the liver kinase B1 (LKB1) signaling pathway. Liver contents of AMP and ADP were augmented by 291 percent and 44 percent by T3 compared to control values (p less than 0.05), respectively, whereas those of ATP decreased by 64% (p less than 0.05), with no significant changes in the total content of adenine nucleotides (AMP + ADP + ATP) at 24 h after T3 administration. Consequently, hepatic ATP/ADP content ratios exhibited 64 percent diminution (p less than 0.05) and those of AMP/ATP increased by 425 percent (p less than 0.05) in T3-treated rats over controls. It is concluded that in vivoT3 administration triggers liver AMPK upregulation in association with significant enhancements in AMPK mRNA expression, AMPK phosphorylation coupled to CaMKKbeta and TAK1 activation, and in AMP/ATP ratios, which may promote enhanced AMPK activity to support T3-induced energy consuming processes such as those of liver preconditioning.

  6. Expression of adenosine 5'-monophosphate-Activated protein kinase (AMPK) in ovine testis (Ovis aries): In vivo regulation by nutritional state.

    Science.gov (United States)

    Taibi, N; Dupont, J; Bouguermouh, Z; Froment, P; Ramé, C; Anane, A; Amirat, Z; Khammar, F

    2017-03-01

    In the present study, we identified AMPK and investigated its potential role in steroidogenesis in vivo in the ovine testis in response to variation in nutritional status (fed control vs. restricted). We performed immunoblotting to show that both active and non-active forms of AMPK exist in ovine testis and liver. In testis, we confirmed these results by immunohistochemistry. We found a correlation between ATP (Adenosine-Triphosphate) levels and the expression of AMPK in liver. Also, low and high caloric diets induce isoform-dependent AMPK expression, with an increase in α2, ß1ß2 and γ1 activity levels. Although the restricted group exhibited an increase in lipid balance, only the triglyceride and HC-VLDL (Cholesterol-Very low density lipoprotein) fractions showed significant differences between groups, suggesting an adaptive mechanism. Moreover, the relatively low rate of non-esterified fatty acid released into the circulation implies re-esterification to compensate for the physiological need. In the fed control group, AMPK activates the production of testosterone in Leydig cells; this is, in turn, associated with an increase in the expression of 3ß-HSD (3 beta hydroxy steroid deshydrogenase), p450scc (Cholesterol side-chain cleavage enzyme) and StAR (Steroidogenic acute regulatory protein) proteins induced by decreased MAPK ERK½ (Extracellular signal-regulated kinase -Mitogen-activated protein kinase) phosphorylation. In contrast, in the restricted group, testosterone secretion was reduced but intracellular cholesterol concentration was not. Furthermore, the combination of high levels of lipoproteins and emergence of the p38 MAP kinase pathway suggest the involvement of pro-inflammatory cytokines, as confirmed by transcriptional repression of the StAR protein. Taken together, these results suggest that AMPK expression is tissue dependent. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Signal processing in microdosimetry

    International Nuclear Information System (INIS)

    Arbel, A.

    1984-01-01

    Signals occurring in microdosimetric measurements cover a dynamic range of 100 dB at a counting rate which normally stays below 10 4 but could increase significantly in case of an accident. The need for high resolution at low energies, non-linear signal processing to accommodate the specified dynamic range, easy calibration and thermal stability are conflicting requirements which pose formidable design problems. These problems are reviewed, and a practical approach to their solution is given employing a single processing channel. (author)

  8. Understanding signal integrity

    CERN Document Server

    Thierauf, Stephen C

    2010-01-01

    This unique book provides you with practical guidance on understanding and interpreting signal integrity (SI) performance to help you with your challenging circuit board design projects. You find high-level discussions of important SI concepts presented in a clear and easily accessible format, including question and answer sections and bulleted lists.This valuable resource features rules of thumb and simple equations to help you make estimates of critical signal integrity parameters without using circuit simulators of CAD (computer-aided design). The book is supported with over 120 illustratio

  9. Electronic signal conditioning

    CERN Document Server

    NEWBY, BRUCE

    1994-01-01

    At technician level, brief references to signal conditioning crop up in a fragmented way in various textbooks, but there has been no single textbook, until now!More advanced texts do exist but they are more mathematical and presuppose a higher level of understanding of electronics and statistics. Electronic Signal Conditioning is designed for HNC/D students and City & Guilds Electronics Servicing 2240 Parts 2 & 3. It will also be useful for BTEC National, Advanced GNVQ, A-level electronics and introductory courses at degree level.

  10. TOR signalling in plants.

    Science.gov (United States)

    Rexin, Daniel; Meyer, Christian; Robaglia, Christophe; Veit, Bruce

    2015-08-15

    Although the eukaryotic TOR (target of rapamycin) kinase signalling pathway has emerged as a key player for integrating nutrient-, energy- and stress-related cues with growth and metabolic outputs, relatively little is known of how this ancient regulatory mechanism has been adapted in higher plants. Drawing comparisons with the substantial knowledge base around TOR kinase signalling in fungal and animal systems, functional aspects of this pathway in plants are reviewed. Both conserved and divergent elements are discussed in relation to unique aspects associated with an autotrophic mode of nutrition and adaptive strategies for multicellular development exhibited by plants. © 2015 Authors; published by Portland Press Limited.

  11. Genomic signal processing

    CERN Document Server

    Shmulevich, Ilya

    2007-01-01

    Genomic signal processing (GSP) can be defined as the analysis, processing, and use of genomic signals to gain biological knowledge, and the translation of that knowledge into systems-based applications that can be used to diagnose and treat genetic diseases. Situated at the crossroads of engineering, biology, mathematics, statistics, and computer science, GSP requires the development of both nonlinear dynamical models that adequately represent genomic regulation, and diagnostic and therapeutic tools based on these models. This book facilitates these developments by providing rigorous mathema

  12. The Arabidopsis thaliana proteome harbors undiscovered multi-domain molecules with functional guanylyl cyclase catalytic centers

    KAUST Repository

    Wong, Aloysius Tze

    2013-07-08

    Background: Second messengers link external cues to complex physiological responses. One such messenger, 3\\',5\\'-cyclic guanosine monophosphate (cGMP), has been shown to play a key role in many physiological responses in plants. However, in higher plants, guanylyl cyclases (GCs), enzymes that generate cGMP from guanosine-5\\'-triphosphate (GTP) have remained elusive until recently. GC search motifs constructed from the alignment of known GCs catalytic centers form vertebrates and lower eukaryotes have led to the identification of a number of plant GCs that have been characterized in vitro and in vivo.Presentation of the hypothesis.Recently characterized GCs in Arabidopsis thaliana contributed to the development of search parameters that can identify novel candidate GCs in plants. We hypothesize that there are still a substantial number (> 40) of multi-domain molecules with potentially functional GC catalytic centers in plants that remain to be discovered and characterized. Testing the hypothesis. The hypothesis can be tested, firstly, by computational methods constructing 3D models of selected GC candidates using available crystal structures as templates. Homology modeling must include substrate docking that can provide support for the structural feasibility of the GC catalytic centers in those candidates. Secondly, recombinant peptides containing the GC domain need to be tested in in vitro GC assays such as the enzyme-linked immune-sorbent assay (ELISA) and/or in mass spectrometry based cGMP assays. In addition, quantification of in vivo cGMP transients with fluorescent cGMP-reporter assays in wild-type or selected mutants will help to elucidate the biological role of novel GCs.Implications of the hypothesis.If it turns out that plants do harbor a large number of functional GC domains as part of multi-domain enzymes, then major new insights will be gained into the complex signal transduction pathways that link cGMP to fundamental processes such as ion transport

  13. Bacterial Biofilm Control by Perturbation of Bacterial Signaling Processes

    DEFF Research Database (Denmark)

    Jakobsen, Tim Holm; Tolker-Nielsen, Tim; Givskov, Michael

    2017-01-01

    -dimeric guanosine monophosphate (cyclic-di-GMP) have gained a lot of attention over the last two decades. More recently, regulatory processes governed by two component regulatory systems and small non-coding RNAs have been increasingly investigated. Here, we review novel findings and potentials of using small...

  14. Vascular nitric oxide: Beyond eNOS

    Directory of Open Access Journals (Sweden)

    Yingzi Zhao

    2015-10-01

    Full Text Available As the first discovered gaseous signaling molecule, nitric oxide (NO affects a number of cellular processes, including those involving vascular cells. This brief review summarizes the contribution of NO to the regulation of vascular tone and its sources in the blood vessel wall. NO regulates the degree of contraction of vascular smooth muscle cells mainly by stimulating soluble guanylyl cyclase (sGC to produce cyclic guanosine monophosphate (cGMP, although cGMP-independent signaling [S-nitrosylation of target proteins, activation of sarco/endoplasmic reticulum calcium ATPase (SERCA or production of cyclic inosine monophosphate (cIMP] also can be involved. In the blood vessel wall, NO is produced mainly from l-arginine by the enzyme endothelial nitric oxide synthase (eNOS but it can also be released non-enzymatically from S-nitrosothiols or from nitrate/nitrite. Dysfunction in the production and/or the bioavailability of NO characterizes endothelial dysfunction, which is associated with cardiovascular diseases such as hypertension and atherosclerosis.

  15. Telmisartan activates endothelial nitric oxide synthase via Ser1177 phosphorylation in vascular endothelial cells.

    Directory of Open Access Journals (Sweden)

    Masahiro Myojo

    Full Text Available Because endothelial nitric oxide synthase (eNOS has anti-inflammatory and anti-arteriosclerotic functions, it has been recognized as one of the key molecules essential for the homeostatic control of blood vessels other than relaxation of vascular tone. Here, we examined whether telmisartan modulates eNOS function through its pleiotropic effect. Administration of telmisartan to mice significantly increased the phosphorylation level of eNOS (Ser1177 in the aortic endothelium, but administration of valsartan had no effect. Similarly, telmisartan treatment of human umbilical vein endothelial cells significantly increased the phosphorylation levels of AMP-activated protein kinase (Thr172 and eNOS and the concentration of intracellular guanosine 3',5'-cyclic monophosphate (cGMP. Furthermore, pretreatment with a p38 mitogen-activated protein kinase (p38 MAPK inhibitor suppressed the increased phosphorylation level of eNOS and intracellular cGMP concentration. These data show that telmisartan increases eNOS activity through Ser1177 phosphorylation in vascular endothelial cells mainly via p38 MAPK signaling.

  16. Evaluation of Antinociceptive Activity of Ethanol Extract of Leaves of Adenanthera pavonina

    Directory of Open Access Journals (Sweden)

    Md. Moniruzzaman

    2015-01-01

    Full Text Available Adenanthera pavonina is a deciduous tree commonly used in the traditional medicine to treat inflammation and rheumatism. The aim of this study was to evaluate the antinociceptive activity of ethanol extract of leaves of A. pavonina (EEAP. EEAP was investigated using various nociceptive models induced thermally or chemically in mice including hot plate and tail immersion test, acetic acid-induced writhing, and glutamate- and formalin-induced licking tests at the doses of 50, 100, and 200 mg/kg body weight (p.o.. In addition, to assess the possible mechanisms, involvement of opioid system was verified using naloxone (2 mg/kg and cyclic guanosine monophosphate (cGMP signaling pathway by methylene blue (MB; 20 mg/kg. The results have demonstrated that EEAP produced a significant and dose-dependent increment in the hot plate latency and tail withdrawal time. It also reduced the number of abdominal constrictions and paw lickings induced by acetic acid and glutamate respectively. EEAP inhibited the nociceptive responses in both phases of formalin test. Besides, the reversal effects of naloxone indicated the association of opioid receptors on the exertion of EEAP action centrally. Moreover, the enhancement of writhing inhibitory activity by MB suggests the possible involvement of cGMP pathway in EEAP-mediated antinociception. These results prove the antinociceptive activity of the leaves of A. pavonina and support the traditional use of this plant.

  17. Molecular, pharmacological, and signaling properties of octopamine receptors from honeybee (Apis mellifera) brain.

    Science.gov (United States)

    Balfanz, Sabine; Jordan, Nadine; Langenstück, Teresa; Breuer, Johanna; Bergmeier, Vera; Baumann, Arnd

    2014-04-01

    G protein-coupled receptors are important regulators of cellular signaling processes. Within the large family of rhodopsin-like receptors, those binding to biogenic amines form a discrete subgroup. Activation of biogenic amine receptors leads to transient changes of intracellular Ca²⁺-([Ca²⁺](i)) or 3',5'-cyclic adenosine monophosphate ([cAMP](i)) concentrations. Both second messengers modulate cellular signaling processes and thereby contribute to long-lasting behavioral effects in an organism. In vivo pharmacology has helped to reveal the functional effects of different biogenic amines in honeybees. The phenolamine octopamine is an important modulator of behavior. Binding of octopamine to its receptors causes elevation of [Ca²⁺](i) or [cAMP](i). To date, only one honeybee octopamine receptor that induces Ca²⁺ signals has been molecularly and pharmacologically characterized. Here, we examined the pharmacological properties of four additional honeybee octopamine receptors. When heterologously expressed, all receptors induced cAMP production after binding to octopamine with EC₅₀(s) in the nanomolar range. Receptor activity was most efficiently blocked by mianserin, a substance with antidepressant activity in vertebrates. The rank order of inhibitory potency for potential receptor antagonists was very similar on all four honeybee receptors with mianserin > cyproheptadine > metoclopramide > chlorpromazine > phentolamine. The subroot of octopamine receptors activating adenylyl cyclases is the largest that has so far been characterized in arthropods, and it should now be possible to unravel the contribution of individual receptors to the physiology and behavior of honeybees. © 2013 International Society for Neurochemistry.

  18. Relative contributions of norspermidine synthesis and signaling pathways to the regulation of Vibrio cholerae biofilm formation.

    Directory of Open Access Journals (Sweden)

    Caitlin K Wotanis

    Full Text Available The polyamine norspermidine is one of the major polyamines synthesized by Vibrionales and has also been found in various aquatic organisms. Norspermidine is among the environmental signals that positively regulate Vibrio cholerae biofilm formation. The NspS/MbaA signaling complex detects extracellular norspermidine and mediates the response to this polyamine. Norspermidine binding to the NspS periplasmic binding protein is thought to inhibit the phosphodiesterase activity of MbaA, increasing levels of the biofilm-promoting second messenger cyclic diguanylate monophosphate, thus enhancing biofilm formation. V. cholerae can also synthesize norspermidine using the enzyme NspC as well as import it from the environment. Deletion of the nspC gene was shown to reduce accumulation of bacteria in biofilms, leading to the conclusion that intracellular norspermidine is also a positive regulator of biofilm formation. Because V. cholerae uses norspermidine to synthesize the siderophore vibriobactin it is possible that intracellular norspermidine is required to obtain sufficient amounts of iron, which is also necessary for robust biofilm formation. The objective of this study was to assess the relative contributions of intracellular and extracellular norspermidine to the regulation of biofilm formation in V. cholerae. We show the biofilm defect of norspermidine synthesis mutants does not result from an inability to produce vibriobactin as vibriobactin synthesis mutants do not have diminished biofilm forming abilities. Furthermore, our work shows that extracellular, but not intracellular norspermidine, is mainly responsible for promoting biofilm formation. We establish that the NspS/MbaA signaling complex is the dominant mediator of biofilm formation in response to extracellular norspermidine, rather than norspermidine synthesized by NspC or imported into the cell.

  19. Television picture signal processing

    NARCIS (Netherlands)

    1998-01-01

    Field or frame memories are often used in television receivers for video signal processing functions, such as noise reduction and/or flicker reduction. Television receivers also have graphic features such as teletext, menu-driven control systems, multilingual subtitling, an electronic TV-Guide, etc.

  20. Signals: Applying Academic Analytics

    Science.gov (United States)

    Arnold, Kimberly E.

    2010-01-01

    Academic analytics helps address the public's desire for institutional accountability with regard to student success, given the widespread concern over the cost of higher education and the difficult economic and budgetary conditions prevailing worldwide. Purdue University's Signals project applies the principles of analytics widely used in…

  1. Communication Signals in Lizards.

    Science.gov (United States)

    Carpenter, Charles C.

    1983-01-01

    Discusses mechanisms and functional intent of visual communication signals in iguanid/agamid lizards. Demonstrated that lizards communicate with each other by using pushups and head nods and that each species does this in its own way, conveying different types of information. (JN)

  2. Modeling binaural signal detection

    NARCIS (Netherlands)

    Breebaart, D.J.

    2001-01-01

    With the advent of multimedia technology and powerful signal processing systems, audio processing and reproduction has gained renewed interest. Examples of products that have been developed are audio coding algorithms to efficiently store and transmit music and speech, or audio reproduction systems

  3. Quantum cloning and signaling

    International Nuclear Information System (INIS)

    Simon, C.; Weihs, G.; Zeilinger, A.

    1999-01-01

    We discuss the close connections between cloning of quantum states and superluminal signaling. We present an optimal universal cloning machine based on stimulated emission recently proposed by the authors. As an instructive example, we show how a scheme for superluminal communication based on this cloning machine fails. (Authors)

  4. "Utilizing" signal detection theory.

    Science.gov (United States)

    Lynn, Spencer K; Barrett, Lisa Feldman

    2014-09-01

    What do inferring what a person is thinking or feeling, judging a defendant's guilt, and navigating a dimly lit room have in common? They involve perceptual uncertainty (e.g., a scowling face might indicate anger or concentration, for which different responses are appropriate) and behavioral risk (e.g., a cost to making the wrong response). Signal detection theory describes these types of decisions. In this tutorial, we show how incorporating the economic concept of utility allows signal detection theory to serve as a model of optimal decision making, going beyond its common use as an analytic method. This utility approach to signal detection theory clarifies otherwise enigmatic influences of perceptual uncertainty on measures of decision-making performance (accuracy and optimality) and on behavior (an inverse relationship between bias magnitude and sensitivity optimizes utility). A "utilized" signal detection theory offers the possibility of expanding the phenomena that can be understood within a decision-making framework. © The Author(s) 2014.

  5. Transient Kinetics of a cGMP-dependent cGMP-specific Phosphodiesterase from Dictyostelium discoideum

    NARCIS (Netherlands)

    Haastert, Peter J.M. van; Lookeren Campagne, Michiel M. van

    1984-01-01

    Chemotactic stimulation of Dictyostelium discoideum cells induces a fast transient increase of cGMP levels which reach a peak at 10 s. Prestimulation levels are recovered in ~30 s, which is achieved mainly by the action of a guanosine 3',5'-monophosphate cGMP-specific phosphodiesterase. This enzyme

  6. Critical nodes in signalling pathways

    DEFF Research Database (Denmark)

    Taniguchi, Cullen M; Emanuelli, Brice; Kahn, C Ronald

    2006-01-01

    Physiologically important cell-signalling networks are complex, and contain several points of regulation, signal divergence and crosstalk with other signalling cascades. Here, we use the concept of 'critical nodes' to define the important junctions in these pathways and illustrate their unique role...... using insulin signalling as a model system....

  7. Nitric oxide synthesis-promoting effects of valsartan in human umbilical vein endothelial cells via the Akt/adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway

    Directory of Open Access Journals (Sweden)

    Yingshuai Zhao

    2017-05-01

    Full Text Available Valsartan (VAL, an antagonist of angiotensin II receptor type 1, has antihypertensive and multiple cardiovascular protective effects. The pleiotropic functions of VAL are related to the increased synthesis and biological activity of intravascular nitric oxide (NO. In this study, the role and mechanisms of VAL in the synthesis of NO were examined in human umbilical vein endothelial cells (HUVECs. Ten µmol/L of VAL was used to treat EA.hy926 cells for 30 minutes, 1, 3, 6, 12, and 24 hours, and three concentrations of VAL (i.e., 10, 1, and 0.1 µmol/L were used to treat EA.hy926 cells for 24 hours. The cells were divided into five groups: control, VAL, VAL + Compound C (adenosine monophosphate-activated protein kinase [AMPK] inhibitor, 1 µmol/L, VAL + LY294002 (Akt [protein kinase B] inhibitor, 10 µmol/L, and VAL + L-nitro-arginine methyl ester (L-NAME, endothelial NO synthase [eNOS] inhibitor, 500 µmol/L groups. The NO content in the VAL-treated HUVEC line (EA.hy926 was detected using the nitrate reductase method, and western blot was used to detect the phosphorylation of Akt, AMPK, and eNOS, as well as the changes in total protein levels. VAL increased NO synthesis in EA.hy926 cells in time- and dose-dependent manners (p < 0.05 and the intracellular phosphorylation levels of Akt, AMPK, and eNOS at the corresponding time points. LY294002, Compound C, and L-NAME could inhibit the VAL-promoted NO synthesis. VAL activated Akt, AMPK, and eNOS, thus promoting NO synthesis and playing a protective role in endothelial cells. These results partially explained the mechanisms underlying the cardiovascular protective effects of VAL.

  8. Sliding charge density wave in the monophosphate tungsten bronze (PO2)4(WO3)2m with alternate stacking of m=4 and m=6 WO3 layers

    International Nuclear Information System (INIS)

    Foury-Leylekian, P.; Sandre, E.; Ravy, S.; Pouget, J.-P.; Elkaim, E.; Roussel, P.; Groult, D.; Labbe, Ph.

    2002-01-01

    The monophosphate tungsten bronzes (PO 2 ) 4 (WO 3 ) 2m form family of two-dimensional metals which exhibit charge density wave (CDW) instabilities. These materials are generally built by the regular stacking of (a,b) layers in which chains made of segments of m WO 6 octahedra directed along the a and a±b directions are delimited. Their electronic structure thus originates from quasi-one-dimensional (1D) bands located on these chains. As a consequence their Fermi surface (FS) exhibits large flat portions whose nesting gives rise to successive CDW instabilities. Here we present a structural study of the CDW instability of the (PO 2 ) 4 (WO 3 ) 10 member formed by the alternate stacking of layers built with segments of m=4 and m=6 WO 6 octahedra. Its ab initio electronic structure calculation shows that the FS of this member exhibits large flat portions which can be extremely well nested. Its best nesting wave vector accounts for the modulation wave vector stabilized by the CDW transition which occurs at 156 K. Because of the regular stacking of layers of different m values the FS is slightly split. The unusual thermal dependence of the x-ray satellite intensity provides evidence that the two types of layers become modulated at different temperature. This also leads to a slight thermal sliding of the CDW-nesting modulation wave vector, which can be accounted for within the framework of a Landau-Ginzburg theory. In addition, the observation of a global hysteresis in the thermal cycling of the satellite intensity, as well as the degradation of the interlayer order upon cooling, suggest the formation of a disordered lattice of dilute solitons. Such solitons allow to accommodate the charge transferred between the two types of layer. Finally the relevance of local charge transfers, at intergrowth defects, for example, to create pinned discommensurations that break the CDW coherence is emphasized in this whole family of bronzes

  9. Apoptotic Cells Induced Signaling for Immune Homeostasis in Macrophages and Dendritic Cells

    Directory of Open Access Journals (Sweden)

    Uriel Trahtemberg

    2017-10-01

    Full Text Available Inefficient and abnormal clearance of apoptotic cells (efferocytosis contributes to systemic autoimmune disease in humans and mice, and inefficient chromosomal DNA degradation by DNAse II leads to systemic polyarthritis and a cytokine storm. By contrast, efficient clearance allows immune homeostasis, generally leads to a non-inflammatory state for both macrophages and dendritic cells (DCs, and contributes to maintenance of peripheral tolerance. As many as 3 × 108 cells undergo apoptosis every hour in our bodies, and one of the primary “eat me” signals expressed by apoptotic cells is phosphatidylserine (PtdSer. Apoptotic cells themselves are major contributors to the “anti-inflammatory” nature of the engulfment process, some by secreting thrombospondin-1 (TSP-1 or adenosine monophosphate and possibly other immune modulating “calm-down” signals that interact with macrophages and DCs. Apoptotic cells also produce “find me” and “tolerate me” signals to attract and immune modulate macrophages and DCs that express specific receptors for some of these signals. Neither macrophages nor DCs are uniform, and each cell type may variably express membrane proteins that function as receptors for PtdSer or for opsonins like complement or opsonins that bind to PtdSer, such as protein S and growth arrest-specific 6. Macrophages and DCs also express scavenger receptors, CD36, and integrins that function via bridging molecules such as TSP-1 or milk fat globule-EGF factor 8 protein and that differentially engage in various multi-ligand interactions between apoptotic cells and phagocytes. In this review, we describe the anti-inflammatory and pro-homeostatic nature of apoptotic cell interaction with the immune system. We do not review some forms of immunogenic cell death. We summarize the known apoptotic cell signaling events in macrophages and DCs that are related to toll-like receptors, nuclear factor kappa B, inflammasome, the lipid

  10. Sinusoidal Representation of Acoustic Signals

    Science.gov (United States)

    Honda, Masaaki

    Sinusoidal representation of acoustic signals has been an important tool in speech and music processing like signal analysis, synthesis and time scale or pitch modifications. It can be applicable to arbitrary signals, which is an important advantage over other signal representations like physical modeling of acoustic signals. In sinusoidal representation, acoustic signals are composed as sums of sinusoid (sine wave) with different amplitudes, frequencies and phases, which is based on the timedependent short-time Fourier transform (STFT). This article describes the principles of acoustic signal analysis/synthesis based on a sinusoid representation with focus on sine waves with rapidly varying frequency.

  11. The newest digital signal processing

    International Nuclear Information System (INIS)

    Lee, Chae Uk

    2002-08-01

    This book deal with the newest digital signal processing, which contains introduction on conception of digital signal processing, constitution and purpose, signal and system such as signal, continuos signal, discrete signal and discrete system, I/O expression on impress response, convolution, mutual connection of system and frequency character,z transform of definition, range, application of z transform and relationship with laplace transform, Discrete fourier, Fast fourier transform on IDFT algorithm and FFT application, foundation of digital filter of notion, expression, types, frequency characteristic of digital filter and design order of filter, Design order of filter, Design of FIR digital filter, Design of IIR digital filter, Adaptive signal processing, Audio signal processing, video signal processing and application of digital signal processing.

  12. Mitochondrial dysfunction precedes depression of AMPK/AKT signaling in insulin resistance induced by high glucose in primary cortical neurons.

    Science.gov (United States)

    Peng, Yunhua; Liu, Jing; Shi, Le; Tang, Ying; Gao, Dan; Long, Jiangang; Liu, Jiankang

    2016-06-01

    Recent studies have demonstrated brain insulin signaling impairment and mitochondrial dysfunction in diabetes. Hyperinsulinemia and hyperlipidemia arising from diabetes have been linked to neuronal insulin resistance, and hyperglycemia induces peripheral sensory neuronal impairment and mitochondrial dysfunction. However, how brain glucose at diabetic conditions elicits cortical neuronal insulin signaling impairment and mitochondrial dysfunction remains unknown. In the present study, we cultured primary cortical neurons with high glucose levels and investigated the neuronal mitochondrial function and insulin response. We found that mitochondrial function was declined in presence of 10 mmol/L glucose, prior to the depression of AKT signaling in primary cortical neurons. We further demonstrated that the cerebral cortex of db/db mice exhibited both insulin resistance and loss of mitochondrial complex components. Moreover, we found that adenosine monophosphate-activated protein kinase (AMPK) inactivation is involved in high glucose-induced mitochondrial dysfunction and insulin resistance in primary cortical neurons and neuroblastoma cells, as well as in cerebral cortex of db/db mice, and all these impairments can be rescued by mitochondrial activator, resveratrol. Taken together, our results extend the finding that high glucose (≥10 mmol/L) comparable to diabetic brain extracellular glucose level leads to neuronal mitochondrial dysfunction and resultant insulin resistance, and targeting mitochondria-AMPK signaling might be a promising strategy to protect against diabetes-related neuronal impairment in central nerves system. We found that high glucose (≥10 mmol/L), comparable to diabetic brain extracellular glucose level, leads to neuronal mitochondrial dysfunction and resultant insulin resistance in an AMPK-dependent manner, and targeting mitochondria-AMPK signaling might be a promising strategy to protect against diabetes-related neuronal impairment in central

  13. Variable reflectivity signal mirrors and signal response measurements

    International Nuclear Information System (INIS)

    Vine, Glenn de; Shaddock, Daniel A; McClelland, David E

    2002-01-01

    Future gravitational wave detectors will include some form of signal mirror in order to alter the signal response of the device. We introduce interferometer configurations which utilize a variable reflectivity signal mirror allowing a tunable peak frequency and variable signal bandwidth. A detector configured with a Fabry-Perot cavity as the signal mirror is compared theoretically with one using a Michelson interferometer for a signal mirror. A system for the measurement of the interferometer signal responses is introduced. This technique is applied to a power-recycled Michelson interferometer with resonant sideband extraction. We present broadband measurements of the benchtop prototype's signal response for a range of signal cavity detunings. This technique is also applicable to most other gravitational wave detector configurations

  14. Variable reflectivity signal mirrors and signal response measurements

    CERN Document Server

    Vine, G D; McClelland, D E

    2002-01-01

    Future gravitational wave detectors will include some form of signal mirror in order to alter the signal response of the device. We introduce interferometer configurations which utilize a variable reflectivity signal mirror allowing a tunable peak frequency and variable signal bandwidth. A detector configured with a Fabry-Perot cavity as the signal mirror is compared theoretically with one using a Michelson interferometer for a signal mirror. A system for the measurement of the interferometer signal responses is introduced. This technique is applied to a power-recycled Michelson interferometer with resonant sideband extraction. We present broadband measurements of the benchtop prototype's signal response for a range of signal cavity detunings. This technique is also applicable to most other gravitational wave detector configurations.

  15. Lymphocyte signaling: beyond knockouts.

    Science.gov (United States)

    Saveliev, Alexander; Tybulewicz, Victor L J

    2009-04-01

    The analysis of lymphocyte signaling was greatly enhanced by the advent of gene targeting, which allows the selective inactivation of a single gene. Although this gene 'knockout' approach is often informative, in many cases, the phenotype resulting from gene ablation might not provide a complete picture of the function of the corresponding protein. If a protein has multiple functions within a single or several signaling pathways, or stabilizes other proteins in a complex, the phenotypic consequences of a gene knockout may manifest as a combination of several different perturbations. In these cases, gene targeting to 'knock in' subtle point mutations might provide more accurate insight into protein function. However, to be informative, such mutations must be carefully based on structural and biophysical data.

  16. Sphingosine signaling and atherogenesis

    DEFF Research Database (Denmark)

    Xu, Cang-bao; Hansen-Schwartz, Jacob; Edvinsson, Lars

    2004-01-01

    Sphingosine-1-phosphate (S1P) has diverse biological functions acting inside cells as a second messenger to regulate cell proliferation and survival, and extracellularly, as a ligand for a group of G protein-coupled receptors (GPCRs) named the endothelial differentiation gene (EDG) family. Five...... closely related GPCRs of EDG family (EDG1, EDG3, EDG5, EDG6, and EDG8) have recently been identified as high-affinity S1P receptors. These receptors are coupled via Gi, Gq, G12/13, and Rho. The signaling pathways are linked to vascular cell migration, proliferation, apoptosis, intracellular Ca2......+ mobilization, and expression of adhesion molecules. The formation of an atherosclerotic lesion occurs through activation of cellular events that include monocyte adhesion to the endothelium and vascular smooth muscle cell (VSMC) migration and proliferation. Thus, S1P signaling may play an important role...

  17. NMR signal transducer

    International Nuclear Information System (INIS)

    Kucheryaev, A.G.; Oliferchuk, N.L.

    1975-01-01

    A signal transducer of nuclear magnetic resonance for simultaneously measuring frequency and intensitivity of two various isotope signals, which are in one specimen is described. The transducer represents radiofrequency circuit with two resonance frequences, which is common for two autodyne generators. To decrease measuring time and to increase recording diagram stability the radiofrequency circuit has LC netork, in the inductivity of which investigated specimen is located; a circuit variable capacity is connected in parallel with one of the autodyne generators. Besides the radiofrequency circuit has an inductance coil in series with a standard specimen inside as well as a variable capacitor connected in parallel with the second autodyne generator. An amplitude of oscillation of each resonance frequency is controlled and adjusted separately. The transducer described can be used for the measurement of a nuclei concentration, isotope concentration and for the spin determination

  18. Biomedical signal analysis

    CERN Document Server

    Rangayyan, Rangaraj M

    2015-01-01

    The book will help assist a reader in the development of techniques for analysis of biomedical signals and computer aided diagnoses with a pedagogical examination of basic and advanced topics accompanied by over 350 figures and illustrations. Wide range of filtering techniques presented to address various applications. 800 mathematical expressions and equations. Practical questions, problems and laboratory exercises. Includes fractals and chaos theory with biomedical applications.

  19. Calcium signaling in liver.

    Science.gov (United States)

    Gaspers, Lawrence D; Thomas, Andrew P

    2005-01-01

    In hepatocytes, hormones linked to the formation of the second messenger inositol 1,4,5-trisphosphate (InsP3) evoke transient increases or spikes in cytosolic free calcium ([Ca2+]i), that increase in frequency with the agonist concentration. These oscillatory Ca2+ signals are thought to transmit the information encoded in the extracellular stimulus to down-stream Ca2+-sensitive metabolic processes. We have utilized both confocal and wide field fluorescence microscopy techniques to study the InsP3-dependent signaling pathway at the cellular and subcellular levels in the intact perfused liver. Typically InsP3-dependent [Ca2+]i spikes manifest as Ca2+ waves that propagate throughout the entire cytoplasm and nucleus, and in the intact liver these [Ca2+]i increases are conveyed through gap junctions to encompass entire lobular units. The translobular movement of Ca2+ provides a means to coordinate the function of metabolic zones of the lobule and thus, liver function. In this article, we describe the characteristics of agonist-evoked [Ca2+]i signals in the liver and discuss possible mechanisms to explain the propagation of intercellular Ca2+ waves in the intact organ.

  20. In adenosine A2B knockouts acute treatment with inorganic nitrate improves glucose disposal, oxidative stress and AMPK signaling in the liver

    Directory of Open Access Journals (Sweden)

    Maria ePeleli

    2015-08-01

    Full Text Available Rationale: Accumulating studies suggest that nitric oxide (NO deficiency and oxidative stress are central pathological mechanisms in type 2 diabetes. Recent findings demonstrate therapeutic effects by boosting a nitrate-nitrite-NO pathway, an alternative pathway for NO formation. This study aimed at investigating the acute effects of inorganic nitrate on glucose and insulin signaling in adenosine A2B receptor knockout mice (A2B-/-, a genetic model of impaired metabolic regulation.Methods: Acute effects of nitrate treatment were investigated in aged wild-type (WT and A2B-/- mice. One hour after injection with nitrate or placebo, metabolic regulation was evaluated by glucose and insulin tolerance tests. NADPH oxidase-mediated superoxide production and AMPK phosphorylation were measured in livers obtained from non-treated or glucose-treated mice, with or without prior nitrate injection. Plasma was used to determine insulin resistance (HOMA-IR and NO signaling.Results: A2B-/- displayed increased body weight, reduced glucose clearance and attenuated overall insulin responses compared with age-matched WT. Nitrate treatment increased circulating levels of nitrate, nitrite and cGMP in A2B-/-, and improved glucose clearance. In WT mice, however, nitrate treatment did not influence glucose clearance. HOMA-IR increased following glucose injection in A2B-/-, but remained at basal levels in mice pretreated with nitrate. NADPH oxidase activity in livers from A2B-/-, but not WT mice, was reduced by nitrate. Livers from A2B-/- displayed reduced AMPK phosphorylation compared with WT mice, and this was increased by nitrate treatment. Injection with the anti-diabetic agent metformin induced similar therapeutic effects in the A2B-/- as observed with nitrate. Conclusion: The A2B-/- mouse is a genetic model of metabolic syndrome. Acute treatment with nitrate improved the metabolic profile, at least partly via reduction in oxidative stress and improved AMPK signaling

  1. Biomedical signal and image processing

    CERN Document Server

    Najarian, Kayvan

    2012-01-01

    INTRODUCTION TO DIGITAL SIGNAL AND IMAGE PROCESSINGSignals and Biomedical Signal ProcessingIntroduction and OverviewWhat is a ""Signal""?Analog, Discrete, and Digital SignalsProcessing and Transformation of SignalsSignal Processing for Feature ExtractionSome Characteristics of Digital ImagesSummaryProblemsFourier TransformIntroduction and OverviewOne-Dimensional Continuous Fourier TransformSampling and NYQUIST RateOne-Dimensional Discrete Fourier TransformTwo-Dimensional Discrete Fourier TransformFilter DesignSummaryProblemsImage Filtering, Enhancement, and RestorationIntroduction and Overview

  2. Signal multiplexing scheme for LINAC

    International Nuclear Information System (INIS)

    Sujo, C.I.; Mohan, Shyam; Joshi, Gopal; Singh, S.K.; Karande, Jitendra

    2004-01-01

    For the proper operation of the LINAC some signals, RF (radio frequency) as well as LF (low frequency) have to be available at the Master Control Station (MCS). These signals are needed to control, calibrate and characterize the RF fields in the resonators. This can be achieved by proper multiplexing of various signals locally and then routing the selected signals to the MCS. A multiplexing scheme has been designed and implemented, which will allow the signals from the selected cavity to the MCS. High isolation between channels and low insertion loss for a given signal are important issues while selecting the multiplexing scheme. (author)

  3. Pathophysiology of Glucocorticoid Signaling.

    Science.gov (United States)

    Vitellius, Géraldine; Trabado, Séverine; Bouligand, Jérôme; Delemer, Brigitte; Lombès, Marc

    2018-06-01

    Glucocorticoids (GC), such as cortisol or dexamethasone, control various physiological functions, notably those involved in development, metabolism, inflammatory processes and stress, and exert most of their effects upon binding to the glucocorticoid receptor (GR, encoded by NR3C1 gene). GC signaling follows several consecutive steps leading to target gene transactivation, including ligand binding, nuclear translocation of ligand-activated GR complexes, DNA binding, coactivator interaction and recruitment of functional transcriptional machinery. Any step may be impaired and may account for altered GC signaling. Partial or generalized glucocorticoid resistance syndrome may result in a reduced level of functional GR, a decreased hormone affinity and binding, a defect in nuclear GR translocation, a decrease or lack of DNA binding and/or post-transcriptional GR modifications. To date, 26 loss-of-function NR3C1 mutations have been reported in the context of hypertension, hirsutism, adrenal hyperplasia or metabolic disorders. These clinical signs are generally associated with biological features including hypercortisolism without negative regulatory feedback loop on the hypothalamic-pituitary-adrenal axis. Patients had often low plasma aldosterone and renin levels despite hypertension. Only one GR gain-of-function mutation has been described associating Cushing's syndrome phenotype with normal urinary-free cortisol. Some GR polymorphisms (ER22/23EK, GR-9β) have been linked to glucocorticoid resistance and a healthier metabolic profile whereas some others seemed to be associated with GC hypersensitivity (N363S, BclI), increasing cardiovascular risk (diabetes type 2, visceral obesity). This review focuses on the earlier findings on the pathophysiology of GR signaling and presents criteria facilitating identification of novel NR3C1 mutations in selected patients. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  4. Purinergic Signalling: Therapeutic Developments

    Directory of Open Access Journals (Sweden)

    Geoffrey Burnstock

    2017-09-01

    Full Text Available Purinergic signalling, i.e., the role of nucleotides as extracellular signalling molecules, was proposed in 1972. However, this concept was not well accepted until the early 1990’s when receptor subtypes for purines and pyrimidines were cloned and characterised, which includes four subtypes of the P1 (adenosine receptor, seven subtypes of P2X ion channel receptors and 8 subtypes of the P2Y G protein-coupled receptor. Early studies were largely concerned with the physiology, pharmacology and biochemistry of purinergic signalling. More recently, the focus has been on the pathophysiology and therapeutic potential. There was early recognition of the use of P1 receptor agonists for the treatment of supraventricular tachycardia and A2A receptor antagonists are promising for the treatment of Parkinson’s disease. Clopidogrel, a P2Y12 antagonist, is widely used for the treatment of thrombosis and stroke, blocking P2Y12 receptor-mediated platelet aggregation. Diquafosol, a long acting P2Y2 receptor agonist, is being used for the treatment of dry eye. P2X3 receptor antagonists have been developed that are orally bioavailable and stable in vivo and are currently in clinical trials for the treatment of chronic cough, bladder incontinence, visceral pain and hypertension. Antagonists to P2X7 receptors are being investigated for the treatment of inflammatory disorders, including neurodegenerative diseases. Other investigations are in progress for the use of purinergic agents for the treatment of osteoporosis, myocardial infarction, irritable bowel syndrome, epilepsy, atherosclerosis, depression, autism, diabetes, and cancer.

  5. Phonocardiography Signal Processing

    CERN Document Server

    Abbas, Abbas K

    2009-01-01

    The auscultation method is an important diagnostic indicator for hemodynamic anomalies. Heart sound classification and analysis play an important role in the auscultative diagnosis. The term phonocardiography refers to the tracing technique of heart sounds and the recording of cardiac acoustics vibration by means of a microphone-transducer. Therefore, understanding the nature and source of this signal is important to give us a tendency for developing a competent tool for further analysis and processing, in order to enhance and optimize cardiac clinical diagnostic approach. This book gives the

  6. Nichtperiodische zeitkontinuierliche Signale

    Science.gov (United States)

    Plaßmann, Wilfried

    Nichtperiodische Signale haben eine große Bedeutung für die Nachrichten- und Datenübertragung, weil Information nur in nichtdeterministischen Signalen enthalten ist (Teil "Nachrichtentechnik", Abschn. 92.4.1). Aber auch für die Energie- und Regelungstechnik sind sie von Interesse, weil sie entweder Ein- und Ausschaltvorgänge erfassen oder den Übergang von einem momentan stationären Zustand in einen neuen darstellen (Kurzschluss im Energieversorgungsnetz, Auftreten einer Störgröße im Regelsystem). Die Fourier- und die Laplacetransformation können bei nichtperiodischen zeitkontinuierlichen Signalen eingesetzt werden.

  7. Generation of earthquake signals

    International Nuclear Information System (INIS)

    Kjell, G.

    1994-01-01

    Seismic verification can be performed either as a full scale test on a shaker table or as numerical calculations. In both cases it is necessary to have an earthquake acceleration time history. This report describes generation of such time histories by filtering white noise. Analogue and digital filtering methods are compared. Different methods of predicting the response spectrum of a white noise signal filtered by a band-pass filter are discussed. Prediction of both the average response level and the statistical variation around this level are considered. Examples with both the IEEE 301 standard response spectrum and a ground spectrum suggested for Swedish nuclear power stations are included in the report

  8. Multiscale Signal Analysis and Modeling

    CERN Document Server

    Zayed, Ahmed

    2013-01-01

    Multiscale Signal Analysis and Modeling presents recent advances in multiscale analysis and modeling using wavelets and other systems. This book also presents applications in digital signal processing using sampling theory and techniques from various function spaces, filter design, feature extraction and classification, signal and image representation/transmission, coding, nonparametric statistical signal processing, and statistical learning theory. This book also: Discusses recently developed signal modeling techniques, such as the multiscale method for complex time series modeling, multiscale positive density estimations, Bayesian Shrinkage Strategies, and algorithms for data adaptive statistics Introduces new sampling algorithms for multidimensional signal processing Provides comprehensive coverage of wavelets with presentations on waveform design and modeling, wavelet analysis of ECG signals and wavelet filters Reviews features extraction and classification algorithms for multiscale signal and image proce...

  9. A Serpentine Way to Signaling

    Indian Academy of Sciences (India)

    IAS Admin

    the cell. The receptor transfers the signal to intracellular proteins ... and molecular mechanisms of GPCR signaling and how this discovery impacts ..... stabilize GPCR–G-protein interaction and resolve dynamics of ... elucidation stages. Kobilka.

  10. Biological signals classification and analysis

    CERN Document Server

    Kiasaleh, Kamran

    2015-01-01

    This authored monograph presents key aspects of signal processing analysis in the biomedical arena. Unlike wireless communication systems, biological entities produce signals with underlying nonlinear, chaotic nature that elude classification using the standard signal processing techniques, which have been developed over the past several decades for dealing primarily with standard communication systems. This book separates what is random from that which appears to be random, and yet is truly deterministic with random appearance. At its core, this work gives the reader a perspective on biomedical signals and the means to classify and process such signals. In particular, a review of random processes along with means to assess the behavior of random signals is also provided. The book also includes a general discussion of biological signals in order to demonstrate the inefficacy of the well-known techniques to correctly extract meaningful information from such signals. Finally, a thorough discussion of recently ...

  11. DMT efficiently inhibits hepatic gluconeogenesis by regulating the Gαq signaling pathway.

    Science.gov (United States)

    Zhou, Ting-Ting; Ma, Fei; Shi, Xiao-Fan; Xu, Xin; Du, Te; Guo, Xiao-Dan; Wang, Gai-Hong; Yu, Liang; Rukachaisirikul, Vatcharin; Hu, Li-Hong; Chen, Jing; Shen, Xu

    2017-08-01

    Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease with complicated pathogenesis and targeting gluconeogenesis inhibition is a promising strategy for anti-diabetic drug discovery. G protein-coupled receptors (GPCRs) are classified as distinct families by heterotrimeric G proteins, primarily including Gαs, Gαi and Gαq. Gαs-coupled GPCRs function potently in the regulation of hepatic gluconeogenesis by activating cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway and Gαi-coupled GPCRs exhibit inhibitory effect on adenylyl cyclase and reduce intracellular cAMP level. However, little is known about the regulation of Gαq-coupled GPCRs in hepatic gluconeogenesis. Here, small-molecule 2-(2,4-dimethoxy-3-methylphenyl)-7-(thiophen-2-yl)-9-(trifluoromethyl)-2,3-dihydropyrido[3',2':4,5]thieno[3,2-d]pyrimidin-4( 1H )-one (DMT) was determined to suppress hepatic glucose production and reduce mRNA levels of gluconeogenic genes. Treatment of DMT in db/db mice decreased fasting blood glucose and hemoglobin A1C (HbA1c) levels, while improved glucose tolerance and pyruvate tolerance. Mechanism study demonstrated that DMT-inhibited gluconeogenesis by regulating the Gαq/phospholipase C (PLC)/inositol-1,4,5-triphosphate receptor (IP3R)-mediated calcium (Ca 2+ )/calmodulin (CaM)/phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (AKT)/forkhead box protein O1 (FOXO1) signaling pathway. To our knowledge, DMT might be the first reported small molecule able to suppress hepatic gluconeogenesis by regulating Gαq signaling, and our current work has also highlighted the potential of DMT in the treatment of T2DM. © 2017 Society for Endocrinology.

  12. Insulin Signaling in Bupivacaine-induced Cardiac Toxicity: Sensitization during Recovery and Potentiation by Lipid Emulsion

    Science.gov (United States)

    Fettiplace, Michael R.; Kowal, Katarzyna; Ripper, Richard; Young, Alexandria; Lis, Kinga; Rubinstein, Israel; Bonini, Marcelo; Minshall, Richard; Weinberg, Guy

    2015-01-01

    Background The impact of local anesthetics on regulation of glucose homeostasis by protein kinase B (Akt) and 5’-Adenosine monophosphate activated protein kinase (AMPK) is unclear but important because of the implications for both local anesthetic toxicity and its reversal by intravenous lipid emulsion (ILE). Methods Sprague-Dawley rats received 10mg/kg bupivacaine over 20 seconds followed by nothing or 10mL/kg ILE (or ILE without bupivacaine). At key time points, heart and kidney were excised. Glycogen content and phosphorylation levels of Akt, p70s6k, s6, IRS1, GSK-3β, AMPK, ACC, TSC2 were quantified. Three animals received Wortmannin to irreversibily inhibit phosphoinositide-3-kinase (Pi3k) signaling. Isolated heart studies were conducted with bupivacaine and LY294002—a reversible Pi3K inhibitor. Results Bupivacaine cardiotoxicity rapidly de-phosphorylated Akt at S473 to 63 ± 5% of baseline and phosphorylated AMPK to 151 ± 19%. AMPK activation inhibited targets downstream of mTORC1 via TSC2. Feedback dephosphorylation of IRS1 to 31 ± 8% of baseline sensitized Akt signaling in hearts resulting in hyper-phosphorylation of Akt at T308 and GSK-3β to 390 ± 64% and 293 ± 50% of baseline respectively. Glycogen accumulated to 142 ± 7% of baseline. Irreversible inhibition of Pi3k upstream of Akt exacerbated bupivacaine cardiotoxicity, while pretreating with a reversible inhibitor delayed onset of toxicity. ILE rapidly phosphorylated Akt at S473 and T308 to 150 ± 23% and 167 ± 10% of baseline, respectively but did not interfere with AMPK or targets of mTORC1. Conclusion Glucose handling by Akt and AMPK is integral to recovery from bupivacaine cardiotoxicity and modulation of these pathways by ILE contributes to lipid resuscitation. PMID:26646023

  13. An odor-specific threshold deficit implicates abnormal cAMP signaling in youths at clinical risk for psychosis.

    Science.gov (United States)

    Kamath, Vidyulata; Moberg, Paul J; Calkins, Monica E; Borgmann-Winter, Karin; Conroy, Catherine G; Gur, Raquel E; Kohler, Christian G; Turetsky, Bruce I

    2012-07-01

    While olfactory deficits have been reported in schizophrenia and youths at-risk for psychosis, few studies have linked these deficits to current pathophysiological models of the illness. There is evidence that disrupted cyclic adenosine 3',5'-monophosphate (cAMP) signaling may contribute to schizophrenia pathology. As cAMP mediates olfactory signal transduction, the degree to which this disruption could manifest in olfactory impairment was ascertained. Odor-detection thresholds to two odorants that differ in the degree to which they activate intracellular cAMP were assessed in clinical risk and low-risk participants. Birhinal assessments of odor-detection threshold sensitivity to lyral and citralva were acquired in youths experiencing prodromal symptoms (n=17) and controls at low risk for developing psychosis (n=15). Citralva and lyral are odorants that differ in cAMP activation; citralva is a strong cAMP activator and lyral is a weak cAMP activator. The overall group-by-odor interaction was statistically significant. At-risk youths showed significantly reduced odor detection thresholds for lyral, but showed intact detection thresholds for citralva. This odor-specific threshold deficit was uncorrelated with deficits in odor identification or discrimination, which were also present. ROC curve analysis revealed that olfactory performance correctly classified at-risk and low-risk youths with greater than 97% accuracy. This study extends prior findings of an odor-specific hyposmia implicating cAMP-mediated signal transduction in schizophrenia and unaffected first-degree relatives to include youths at clinical risk for developing the disorder. These results suggest that dysregulation of cAMP signaling may be present during the psychosis prodrome. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Two-dimensional signal analysis

    CERN Document Server

    Garello, René

    2010-01-01

    This title sets out to show that 2-D signal analysis has its own role to play alongside signal processing and image processing.Concentrating its coverage on those 2-D signals coming from physical sensors (such as radars and sonars), the discussion explores a 2-D spectral approach but develops the modeling of 2-D signals and proposes several data-oriented analysis techniques for dealing with them. Coverage is also given to potential future developments in this area.

  15. Wireless data signal transmission system

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a method for providing a radio frequency signal for transmission, a system for providing a radio frequency signal for transmission and a method for wireless data transmission between a transmitter and a receiver.......The present invention relates to a method for providing a radio frequency signal for transmission, a system for providing a radio frequency signal for transmission and a method for wireless data transmission between a transmitter and a receiver....

  16. Astrocytes in endocannabinoid signalling.

    Science.gov (United States)

    Navarrete, Marta; Díez, Adolfo; Araque, Alfonso

    2014-10-19

    Astrocytes are emerging as integral functional components of synapses, responding to synaptically released neurotransmitters and regulating synaptic transmission and plasticity. Thus, they functionally interact with neurons establishing tripartite synapses: a functional concept that refers to the existence of communication between astrocytes and neurons and its crucial role in synaptic function. Here, we discuss recent evidence showing that astrocytes are involved in the endocannabinoid (ECB) system, responding to exogenous cannabinoids as well as ECBs through activation of type 1 cannabinoid receptors, which increase intracellular calcium and stimulate the release of glutamate that modulates synaptic transmission and plasticity. We also discuss the consequences of ECB signalling in tripartite synapses on the astrocyte-mediated regulation of synaptic function, which reveal novel properties of synaptic regulation by ECBs, such as the spatially controlled dual effect on synaptic strength and the lateral potentiation of synaptic efficacy. Finally, we discuss the potential implications of ECB signalling for astrocytes in brain pathology and animal behaviour. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  17. Involvement of adenosine monophosphate activated kinase in interleukin-6 regulation of steroidogenic acute regulatory protein and cholesterol side chain cleavage enzyme in the bovine zona fasciculata and zona reticularis.

    Science.gov (United States)

    De Silva, Matharage S I; Dayton, Adam W; Rhoten, Lance R; Mallett, John W; Reese, Jared C; Squires, Mathieu D; Dalley, Andrew P; Porter, James P; Judd, Allan M

    2018-06-01

    In bovine adrenal zona fasciculata (ZF) and NCI-H295R cells, interleukin-6 (IL-6) increases cortisol release, increases expression of steroidogenic acute regulatory protein (StAR), cholesterol side chain cleavage enzyme (P450scc), and steroidogenic factor 1 (SF-1) (increases steroidogenic proteins), and decreases the expression of adrenal hypoplasia congenita-like protein (DAX-1) (inhibits steroidogenic proteins). In contrast, IL-6 decreases bovine adrenal zona reticularis (ZR) androgen release, StAR, P450scc, and SF-1 expression, and increases DAX-1 expression. Adenosine monophosphate (AMP) activated kinase (AMPK) regulates steroidogenesis, but its role in IL-6 regulation of adrenal steroidogenesis is unknown. In the present study, an AMPK activator (AICAR) increased (P < 0.01) NCI-H295R StAR promoter activity, StAR and P450scc expression, and the phosphorylation of AMPK (PAMPK) and acetyl-CoA carboxylase (PACC) (indexes of AMPK activity). In ZR (decreased StAR, P450scc, SF-1, increased DAX-1) (P < 0.01) and ZF tissues (increased StAR, P450scc, SF-1, decreased DAX-1) (P < 0.01), AICAR modified StAR, P450scc, SF-1 and DAX-1 mRNAs/proteins similar to the effects of IL-6. The activity (increased PAMPK and PACC) (P < 0.01) of AMPK in the ZF and ZR was increased by AICAR and IL-6. In support of an AMPK role in IL-6 ZF and ZR effects, the AMPK inhibitor compound C blocked (P < 0.01) the effects of IL-6 on the expression of StAR, P450scc, SF-1, and DAX-1. Therefore, IL-6 modification of the expression of StAR and P450scc in the ZF and ZR may involve activation of AMPK and these changes may be related to changes in the expression of SF-1 and DAX-1. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Development of a simple and efficient method for assaying cytidine monophosphate sialic acid synthetase activity using an enzymatic reduced nicotinamide adenine dinucleotide/oxidized nicotinamide adenine dinucleotide converting system.

    Science.gov (United States)

    Fujita, Akiko; Sato, Chihiro; Münster-Kühnel, Anja-K; Gerardy-Schahn, Rita; Kitajima, Ken

    2005-02-01

    A new reliable method to assay the activity of cytidine monophosphate sialic acid (CMP-Sia) synthetase (CSS) has been developed. The activation of sialic acids (Sia) to CMP-Sia is a prerequisite for the de novo synthesis of sialoglycoconjugates. In vertebrates, CSS has been cloned from human, mouse, and rainbow trout, and the crystal structure has been resolved for the mouse enzyme. The mouse and rainbow trout enzyme have been compared with respect to substrate specificity, demonstrating that the mouse enzyme exhibits a pronounced specificity for N-acetylneuraminic acid (Neu5Ac), while the rainbow trout CSS is equally active with either of three Sia species, Neu5Ac, N-glycolylneuraminic acid (Neu5Gc), and deaminoneuraminic acid (KDN). However, molecular details that explain the pronounced substrate specificities are unknown. Understanding the catalytic mechanisms of these enzymes is of major importance, since CSSs play crucial roles in cellular sialylation patterns and thus are potential drug targets in a number of pathophysiological situations. The availability of the cDNAs and the obtained structural data enable rational approaches; however, these efforts are limited by the lack of a reliable high-throughput assay system. Here we describe a new assay system that allows product quantification in a reduced nicotinamide adenine dinucleotide (NADH)-dependent color reaction. The activation reaction catalyzed by CSS, CTP+Sia-->CMP-Sia+pyrophosphate, was evaluated by a consumption of Sia, which corresponds to that of NADH on the following two successive reactions: (i) Sia-->pyruvate+ManNAc (or Man), catalyzed by a sialic acid lyase (SAL), and (ii) pyruvate+NADH-->lactate+oxidized nicotinamide adenine dinucleotide (NAD+), catalyzed by a lactate dehydrogenase (LDH). Consumption of NADH can be photometrically monitored on a microtiter plate reader for a number of test samples at the same time. Furthermore, based on the quantification of CSS used in the SAL/LDH assay

  19. 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.

  20. Phosphoinositide metabolism links cGMP-dependent protein kinase G to essential Ca²⁺ signals at key decision points in the life cycle of malaria parasites.

    Directory of Open Access Journals (Sweden)

    Mathieu Brochet

    2014-03-01

    Full Text Available Many critical events in the Plasmodium life cycle rely on the controlled release of Ca²⁺ from intracellular stores to activate stage-specific Ca²⁺-dependent protein kinases. Using the motility of Plasmodium berghei ookinetes as a signalling paradigm, we show that the cyclic guanosine monophosphate (cGMP-dependent protein kinase, PKG, maintains the elevated level of cytosolic Ca²⁺ required for gliding motility. We find that the same PKG-dependent pathway operates upstream of the Ca²⁺ signals that mediate activation of P. berghei gametocytes in the mosquito and egress of Plasmodium falciparum merozoites from infected human erythrocytes. Perturbations of PKG signalling in gliding ookinetes have a marked impact on the phosphoproteome, with a significant enrichment of in vivo regulated sites in multiple pathways including vesicular trafficking and phosphoinositide metabolism. A global analysis of cellular phospholipids demonstrates that in gliding ookinetes PKG controls phosphoinositide biosynthesis, possibly through the subcellular localisation or activity of lipid kinases. Similarly, phosphoinositide metabolism links PKG to egress of P. falciparum merozoites, where inhibition of PKG blocks hydrolysis of phosphatidylinostitol (4,5-bisphosphate. In the face of an increasing complexity of signalling through multiple Ca²⁺ effectors, PKG emerges as a unifying factor to control multiple cellular Ca²⁺ signals essential for malaria parasite development and transmission.

  1. Signals and systems for dummies

    CERN Document Server

    Wickert, Mark

    2013-01-01

    Getting mixed signals in your signals and systems course? The concepts covered in a typical signals and systems course are often considered by engineering students to be some of the most difficult to master. Thankfully, Signals & Systems For Dummies is your intuitive guide to this tricky course, walking you step-by-step through some of the more complex theories and mathematical formulas in a way that is easy to understand. From Laplace Transforms to Fourier Analyses, Signals & Systems For Dummies explains in plain English the difficult concepts that can trip you up

  2. Detection of signals in noise

    CERN Document Server

    Whalen, Anthony D; Declaris, Nicholas

    1971-01-01

    Detection of Signals in Noise serves as an introduction to the principles and applications of the statistical theory of signal detection. The book discusses probability and random processes; narrowband signals, their complex representation, and their properties described with the aid of the Hilbert transform; and Gaussian-derived processes. The text also describes the application of hypothesis testing for the detection of signals and the fundamentals required for statistical detection of signals in noise. Problem exercises, references, and a supplementary bibliography are included after each c

  3. Multimodal signal variation in space and time : how important is matching a signal with its signaler?

    OpenAIRE

    Taylor, Ryan C.; Klein, Barrett; Stein, Joey; Ryan, Michael J.

    2011-01-01

    Multimodal signals (acoustic+visual) are known to be used by many anuran amphibians during courtship displays. The relative degree to which each signal component influences female mate choice, however, remains poorly understood. In this study we used a robotic frog with an inflating vocal sac and acoustic playbacks to document responses of female túngara frogs to unimodal signal components (acoustic and visual). We then tested female responses to a synchronous multimodal signal. Finally, we t...

  4. Purinergic signalling and diabetes

    DEFF Research Database (Denmark)

    Burnstock, Geoffrey; Novak, Ivana

    2013-01-01

    , and common and divergent roles of receptors for nucleotides and nucleosides in different organ systems will be given. This integrated picture will aid our understanding of the challenges of the potential and currently used drugs targeted to specific organ/cells or disorders associated with diabetes.......The pancreas is an organ with a central role in nutrient breakdown, nutrient sensing and release of hormones regulating whole body nutrient homeostasis. In diabetes mellitus, the balance is broken-cells can be starving in the midst of plenty. There are indications that the incidence of diabetes...... type 1 and 2, and possibly pancreatogenic diabetes, is rising globally. Events leading to insulin secretion and action are complex, but there is emerging evidence that intracellular nucleotides and nucleotides are not only important as intracellular energy molecules but also as extracellular signalling...

  5. Machine intelligence and signal processing

    CERN Document Server

    Vatsa, Mayank; Majumdar, Angshul; Kumar, Ajay

    2016-01-01

    This book comprises chapters on key problems in machine learning and signal processing arenas. The contents of the book are a result of a 2014 Workshop on Machine Intelligence and Signal Processing held at the Indraprastha Institute of Information Technology. Traditionally, signal processing and machine learning were considered to be separate areas of research. However in recent times the two communities are getting closer. In a very abstract fashion, signal processing is the study of operator design. The contributions of signal processing had been to device operators for restoration, compression, etc. Applied Mathematicians were more interested in operator analysis. Nowadays signal processing research is gravitating towards operator learning – instead of designing operators based on heuristics (for example wavelets), the trend is to learn these operators (for example dictionary learning). And thus, the gap between signal processing and machine learning is fast converging. The 2014 Workshop on Machine Intel...

  6. Wavelet analysis for nonstationary signals

    International Nuclear Information System (INIS)

    Penha, Rosani Maria Libardi da

    1999-01-01

    Mechanical vibration signals play an important role in anomalies identification resulting of equipment malfunctioning. Traditionally, Fourier spectral analysis is used where the signals are assumed to be stationary. However, occasional transient impulses and start-up process are examples of nonstationary signals that can be found in mechanical vibrations. These signals can provide important information about the equipment condition, as early fault detection. The Fourier analysis can not adequately be applied to nonstationary signals because the results provide data about the frequency composition averaged over the duration of the signal. In this work, two methods for nonstationary signal analysis are used: Short Time Fourier Transform (STFT) and wavelet transform. The STFT is a method of adapting Fourier spectral analysis for nonstationary application to time-frequency domain. To have a unique resolution throughout the entire time-frequency domain is its main limitation. The wavelet transform is a new analysis technique suitable to nonstationary signals, which handles the STFT drawbacks, providing multi-resolution frequency analysis and time localization in a unique time-scale graphic. The multiple frequency resolutions are obtained by scaling (dilatation/compression) the wavelet function. A comparison of the conventional Fourier transform, STFT and wavelet transform is made applying these techniques to: simulated signals, arrangement rotor rig vibration signal and rotate machine vibration signal Hanning window was used to STFT analysis. Daubechies and harmonic wavelets were used to continuos, discrete and multi-resolution wavelet analysis. The results show the Fourier analysis was not able to detect changes in the signal frequencies or discontinuities. The STFT analysis detected the changes in the signal frequencies, but with time-frequency resolution problems. The wavelet continuos and discrete transform demonstrated to be a high efficient tool to detect

  7. Seismic signals hard clipping overcoming

    Science.gov (United States)

    Olszowa, Paula; Sokolowski, Jakub

    2018-01-01

    In signal processing the clipping is understand as the phenomenon of limiting the signal beyond certain threshold. It is often related to overloading of a sensor. Two particular types of clipping are being recognized: soft and hard. Beyond the limiting value soft clipping reduces the signal real gain while the hard clipping stiffly sets the signal values at the limit. In both cases certain amount of signal information is lost. Obviously if one possess the model which describes the considered signal and the threshold value (which might be slightly more difficult to obtain in the soft clipping case), the attempt of restoring the signal can be made. Commonly it is assumed that the seismic signals take form of an impulse response of some specific system. This may lead to belief that the sine wave may be the most appropriate to fit in the clipping period. However, this should be tested. In this paper the possibility of overcoming the hard clipping in seismic signals originating from a geoseismic station belonging to an underground mine is considered. A set of raw signals will be hard-clipped manually and then couple different functions will be fitted and compared in terms of least squares. The results will be then analysed.

  8. Pleiotrophin Signaling Through PTNR in Breast Cancer

    National Research Council Canada - National Science Library

    Powers, Ciaron

    2001-01-01

    ... of intracellular signaling cascades. The pleiotrophin signaling pathway is known to be important in angiogenesis and breast cancer growth, but the exact mechanisms of pleiotrophin signaling remain undefined...

  9. Digitally programmable signal generator

    International Nuclear Information System (INIS)

    Priatko, G.J.; Kaskey, J.A.

    1988-01-01

    A digitally programmable signal generator (DPSG) includes a first memory from which data is written into a second memory formed of n banks. Each bank includes four memories and a multiplexer, the banks being read once during each time frame, the read-out bits being multiplexed and fed out serially in synchronism with a plurality of clock pulses occuring during a time frame. The resulting serial bit streams may be fed in parallel to a digital-to-analog converter. The DPSG can be used in applications such as Atomic Vapor Laser Isotope Separation (AVLIS) to create an optimal match between the process laser's spectral profile and that of the vaporized material, optical telecommunications, non-optical telecommunication in the microwave and radio spectrum, radar, electronic countermeasures, high speed computer interconnects, local area networks, high definition video transport and the multiplexing of large quantities of slow digital memory into high speed data streams. This invention extends the operation of DPSGs into the GHz range. (author)

  10. Volcanic signals in oceans

    KAUST Repository

    Stenchikov, Georgiy L.

    2009-08-22

    Sulfate aerosols resulting from strong volcanic explosions last for 2–3 years in the lower stratosphere. Therefore it was traditionally believed that volcanic impacts produce mainly short-term, transient climate perturbations. However, the ocean integrates volcanic radiative cooling and responds over a wide range of time scales. The associated processes, especially ocean heat uptake, play a key role in ongoing climate change. However, they are not well constrained by observations, and attempts to simulate them in current climate models used for climate predictions yield a range of uncertainty. Volcanic impacts on the ocean provide an independent means of assessing these processes. This study focuses on quantification of the seasonal to multidecadal time scale response of the ocean to explosive volcanism. It employs the coupled climate model CM2.1, developed recently at the National Oceanic and Atmospheric Administration\\'s Geophysical Fluid Dynamics Laboratory, to simulate the response to the 1991 Pinatubo and the 1815 Tambora eruptions, which were the largest in the 20th and 19th centuries, respectively. The simulated climate perturbations compare well with available observations for the Pinatubo period. The stronger Tambora forcing produces responses with higher signal-to-noise ratio. Volcanic cooling tends to strengthen the Atlantic meridional overturning circulation. Sea ice extent appears to be sensitive to volcanic forcing, especially during the warm season. Because of the extremely long relaxation time of ocean subsurface temperature and sea level, the perturbations caused by the Tambora eruption could have lasted well into the 20th century.

  11. Multimodal signalling in estrildid finches

    DEFF Research Database (Denmark)

    Gomes, A. C. R.; Funghi, C.; Soma, M.

    2017-01-01

    Sexual traits (e.g. visual ornaments, acoustic signals, courtship behaviour) are often displayed together as multimodal signals. Some hypotheses predict joint evolution of different sexual signals (e.g. to increase the efficiency of communication) or that different signals trade off with each other...... (e.g. due to limited resources). Alternatively, multiple signals may evolve independently for different functions, or to communicate different information (multiple message hypothesis). We evaluated these hypotheses with a comparative study in the family Estrildidae, one of the largest songbird...... compromise, but generally courtship dance also evolved independently from other signals. Instead of correlated evolution, we found that song, dance and colour are each related to different socio-ecological traits. Song complexity evolved together with ecological generalism, song performance with investment...

  12. Fundamentals of statistical signal processing

    CERN Document Server

    Kay, Steven M

    1993-01-01

    A unified presentation of parameter estimation for those involved in the design and implementation of statistical signal processing algorithms. Covers important approaches to obtaining an optimal estimator and analyzing its performance; and includes numerous examples as well as applications to real- world problems. MARKETS: For practicing engineers and scientists who design and analyze signal processing systems, i.e., to extract information from noisy signals — radar engineer, sonar engineer, geophysicist, oceanographer, biomedical engineer, communications engineer, economist, statistician, physicist, etc.

  13. Semi-classical signal analysis

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2012-09-30

    This study introduces a new signal analysis method, based on a semi-classical approach. The main idea in this method is to interpret a pulse-shaped signal as a potential of a Schrödinger operator and then to use the discrete spectrum of this operator for the analysis of the signal. We present some numerical examples and the first results obtained with this method on the analysis of arterial blood pressure waveforms. © 2012 Springer-Verlag London Limited.

  14. Elucidation of the Signal Transduction Pathways Activated by the Plant Natriuretic Peptide AtPNP-A

    KAUST Repository

    Turek, Ilona

    2014-11-01

    Plant natriuretic peptides (PNPs) comprise a novel class of hormones that share some sequence similarity in the active site with their animal analogues that function as regulators of salt and water balance. A PNP present in Arabidopsis thaliana (AtPNP-A) has been assigned a role in abiotic and biotic stress responses, and the recombinant protein has been demonstrated to elicit cyclic guanosine monophosphate (cGMP)-dependent stomatal guard cell opening, regulate ion movements, and induce osmoticum-dependent water uptake. Although the importance of the hormone in maintaining ion and fluid homeostasis has been established, key components of the AtPNP-A-dependent signal transduction pathway remain unknown. Since identification of the binding partners of AtPNP-A, including its receptor(s), is fundamental to understanding the mode of its action at the molecular level, comprehensive protein-protein interaction studies, involving yeast two-hybrid screening, affinity-based assays, protein cross-linking and co-immunoprecipitation followed by mass spectrometric (MS) analyses have been performed. Several candidate binding partners of AtPNP-A identified with at least two independent methods were subsequently expressed as recombinant proteins, purified, and the specificity of their interactions with the recombinant AtPNP-A was verified using surface plasmon resonance. Several specific binary interactants of AtPNP-A were subjected to functional assays aimed at unraveling the consequences of the interactions in planta. These experiments have revealed that reactive oxygen species (ROS) are novel secondary messengers involved in the transduction of AtPNP-A signal in suspension-cultured cells of A. thaliana (Col-0). Further insight into the AtPNP-A dependent signalling events occurring in suspension-cultured cells in ROS-dependent or ROS-independent manner have been obtained from the large-scale proteomics study employing tandem mass tag (TMT) labelling followed by MS analysis to

  15. Signal generation in gas detectors

    International Nuclear Information System (INIS)

    Stillman, A.

    1993-01-01

    This tutorial describes the generation of electrical signals in gas detectors. Ionization of the gas by the passage of charged particles generates these signals. Starting with the Bethe-Bloch equation, the treatment is a general introduction to the production of ion-pairs in gas devices. I continue with the characterization of the ionization as an electrical signal, and calculate the signal current in a simple example. Another example demonstrates the effect of space charge on the design of a detector. The AGS Booster ionization profile monitor is a model for this calculation

  16. Paracrine signaling in a bacterium.

    Science.gov (United States)

    López, Daniel; Vlamakis, Hera; Losick, Richard; Kolter, Roberto

    2009-07-15

    Cellular differentiation is triggered by extracellular signals that cause target cells to adopt a particular fate. Differentiation in bacteria typically involves autocrine signaling in which all cells in the population produce and respond to the same signal. Here we present evidence for paracrine signaling in bacterial populations-some cells produce a signal to which only certain target cells respond. Biofilm formation in Bacillus involves two centrally important signaling molecules, ComX and surfactin. ComX triggers the production of surfactin. In turn, surfactin causes a subpopulation of cells to produce an extracellular matrix. Cells that produced surfactin were themselves unable to respond to it. Likewise, once surfactin-responsive cells commenced matrix production, they no longer responded to ComX and could not become surfactin producers. Insensitivity to ComX was the consequence of the extracellular matrix as mutant cells unable to make matrix responded to both ComX and surfactin. Our results demonstrate that extracellular signaling was unidirectional, with one subpopulation producing a signal and a different subpopulation responding to it. Paracrine signaling in a bacterial population ensures the maintenance, over generations, of particular cell types even in the presence of molecules that would otherwise cause those cells to differentiate into other cell types.

  17. The Evolution of Covert Signaling.

    Science.gov (United States)

    Smaldino, Paul E; Flamson, Thomas J; McElreath, Richard

    2018-03-20

    Human sociality depends upon the benefits of mutual aid and extensive communication. However, diverse norms and preferences complicate mutual aid, and ambiguity in meaning hinders communication. Here we demonstrate that these two problems can work together to enhance cooperation through the strategic use of deliberately ambiguous signals: covert signaling. Covert signaling is the transmission of information that is accurately received by its intended audience but obscured when perceived by others. Such signals may allow coordination and enhanced cooperation while also avoiding the alienation or hostile reactions of individuals with different preferences. Although the empirical literature has identified potential mechanisms of covert signaling, such as encryption in humor, there is to date no formal theory of its dynamics. We introduce a novel mathematical model to assess when a covert signaling strategy will evolve, as well as how receiver attitudes coevolve with covert signals. Covert signaling plausibly serves an important function in facilitating within-group cooperative assortment by allowing individuals to pair up with similar group members when possible and to get along with dissimilar ones when necessary. This mechanism has broad implications for theories of signaling and cooperation, humor, social identity, political psychology, and the evolution of human cultural complexity.

  18. Signal anomaly detection and characterization

    International Nuclear Information System (INIS)

    Morgenstern, V.M.; Upadhyaya, B.R.; Gloeckler, O.

    1988-08-01

    As part of a comprehensive signal validation system, we have developed a signal anomaly detector, without specifically establishing the cause of the anomaly. A signal recorded from process instrumentation is said to have an anomaly, if during steady-state operation, the deviation in the level of the signal, its root-mean-square (RMS) value, or its statistical distribution changes by a preset value. This deviation could be an unacceptable increase or a decrease in the quantity being monitored. An anomaly in a signal may be characterized by wideband or single-frequency noise, bias error, pulse-type error, nonsymmetric behavior, or a change in the signal bandwidth. Various signatures can be easily computed from data samples and compared against specified threshold values. We want to point out that in real processes, pulses can appear with different time widths, and at different rates of change of the signal. Thus, in characterizing an anomaly as a pulse-type, the fastest pulse width is constrained by the signal sampling interval. For example, if a signal is sampled at 100 Hz, we will not be able to detect pulses occurring at kHz rates. Discussion with utility and Combustion Engineering personnel indicated that it is not practical to detect pulses having a narrow time width. 9 refs., 11 figs., 8 tabs

  19. Thermal resonance in signal transmission

    International Nuclear Information System (INIS)

    Reigada, Ramon; Sarmiento, Antonio; Lindenberg, Katja

    2001-01-01

    We use temperature tuning to control signal propagation in simple one-dimensional arrays of masses connected by hard anharmonic springs and with no local potentials. In our numerical model a sustained signal is applied at one site of a chain immersed in a thermal environment and the signal-to-noise ratio is measured at each oscillator. We show that raising the temperature can lead to enhanced signal propagation along the chain, resulting in thermal resonance effects akin to the resonance observed in arrays of bistable systems

  20. Thermal resonance in signal transmission

    Energy Technology Data Exchange (ETDEWEB)

    Reigada, Ramon; Sarmiento, Antonio; Lindenberg, Katja

    2001-06-01

    We use temperature tuning to control signal propagation in simple one-dimensional arrays of masses connected by hard anharmonic springs and with no local potentials. In our numerical model a sustained signal is applied at one site of a chain immersed in a thermal environment and the signal-to-noise ratio is measured at each oscillator. We show that raising the temperature can lead to enhanced signal propagation along the chain, resulting in thermal resonance effects akin to the resonance observed in arrays of bistable systems.

  1. PKA and PDE4D3 anchoring to AKAP9 provides distinct regulation of cAMP signals at the centrosome

    Science.gov (United States)

    Terrin, Anna; Monterisi, Stefania; Stangherlin, Alessandra; Zoccarato, Anna; Koschinski, Andreas; Surdo, Nicoletta C.; Mongillo, Marco; Sawa, Akira; Jordanides, Niove E.; Mountford, Joanne C.

    2012-01-01

    Previous work has shown that the protein kinase A (PKA)–regulated phosphodiesterase (PDE) 4D3 binds to A kinase–anchoring proteins (AKAPs). One such protein, AKAP9, localizes to the centrosome. In this paper, we investigate whether a PKA–PDE4D3–AKAP9 complex can generate spatial compartmentalization of cyclic adenosine monophosphate (cAMP) signaling at the centrosome. Real-time imaging of fluorescence resonance energy transfer reporters shows that centrosomal PDE4D3 modulated a dynamic microdomain within which cAMP concentration selectively changed over the cell cycle. AKAP9-anchored, centrosomal PKA showed a reduced activation threshold as a consequence of increased autophosphorylation of its regulatory subunit at S114. Finally, disruption of the centrosomal cAMP microdomain by local displacement of PDE4D3 impaired cell cycle progression as a result of accumulation of cells in prophase. Our findings describe a novel mechanism of PKA activity regulation that relies on binding to AKAPs and consequent modulation of the enzyme activation threshold rather than on overall changes in cAMP levels. Further, we provide for the first time direct evidence that control of cell cycle progression relies on unique regulation of centrosomal cAMP/PKA signals. PMID:22908311

  2. Hypoxia induces cancer-associated cAMP/PKA signalling through HIF-mediated transcriptional control of adenylyl cyclases VI and VII.

    Science.gov (United States)

    Simko, Veronika; Iuliano, Filippo; Sevcikova, Andrea; Labudova, Martina; Barathova, Monika; Radvak, Peter; Pastorekova, Silvia; Pastorek, Jaromir; Csaderova, Lucia

    2017-08-31

    Hypoxia is a phenomenon often arising in solid tumours, linked to aggressive malignancy, bad prognosis and resistance to therapy. Hypoxia-inducible factor-1 has been identified as a key mediator of cell and tissue adaptation to hypoxic conditions through transcriptional activation of many genes involved in glucose metabolism and other cancer-related processes, such as angiogenesis, cell survival and cell invasion. Cyclic adenosine 3'5'-monophosphate is one of the most ancient and evolutionarily conserved signalling molecules and the cAMP/PKA signalling pathway plays an important role in cellular adaptation to hypoxia. We have investigated possible new mechanisms behind hypoxic activation of the cAMP/PKA pathway. For the first time, we have shown that hypoxia induces transcriptional up-regulation of the system of adenylyl cyclases, enzymes responsible for cAMP production, in a panel of carcinoma cell lines of various origin. Our data prove functional relevance of the hypoxic increase of adenylyl cyclases VI and VII at least partially mediated by HIF-1 transcription factor. We have identified adenylyl cyclase VI and VII isoforms as mediators of cellular response to hypoxia, which led to the elevation of cAMP levels and enhanced PKA activity, with an impact on cell migration and pH regulation.

  3. Osthole Enhances Osteogenesis in Osteoblasts by Elevating Transcription Factor Osterix via cAMP/CREB Signaling In Vitro and In Vivo

    Directory of Open Access Journals (Sweden)

    Zhong-Rong Zhang

    2017-06-01

    Full Text Available Anabolic anti-osteoporotic agents are desirable for treatment and prevention of osteoporosis and fragility fractures. Osthole is a coumarin derivative extracted from the medicinal herbs Cnidium monnieri (L. Cusson and Angelica pubescens Maxim.f. Osthole has been reported with osteogenic and anti-osteoporotic properties, whereas the underlying mechanism of its benefit still remains unclear. The objective of the present study was to investigate the osteopromotive action of osthole on mouse osteoblastic MC3T3-E1 cells and on mouse femoral fracture repair, and to explore the interaction between osthole-induced osteopromotive effect and cyclic adenosine monophosphate (cAMP elevating effect. Osthole treatment promoted osteogenesis in osteoblasts by enhancing alkaline phosphatase (ALP activity and mineralization. Oral gavage of osthole enhanced fracture repair and increased bone strength. Mechanistic study showed osthole triggered the cAMP/CREB pathway through the elevation of the intracellular cAMP level and activation of the phosphorylation of the cAMP response element-binding protein (CREB. Blockage of cAMP/CREB downstream signals with protein kinase A (PKA inhibitor KT5720 partially suppressed osthole-mediated osteogenesis by inhibiting the elevation of transcription factor, osterix. In conclusion, osthole shows osteopromotive effect on osteoblasts in vitro and in vivo. Osthole-mediated osteogenesis is related to activation of the cAMP/CREB signaling pathway and downstream osterix expression.

  4. [Effect of baicalin on ATPase and LDH and its regulatory effect on the AC/cAMP/PKA signaling pathway in rats with attention deficit hyperactivity disorder].

    Science.gov (United States)

    Zhou, Rong-Yi; Wang, Jiao-Jiao; You, Yue; Sun, Ji-Chao; Song, Yu-Chen; Yuan, Hai-Xia; Han, Xin-Min

    2017-05-01

    To study the effect of baicalin on synaptosomal adenosine triphosphatase (ATPase) and lactate dehydrogenase (LDH) and its regulatory effect on the adenylate cyclase (AC)/cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway in rats with attention deficit hyperactivity disorder (ADHD). A total of 40 SHR rats were randomly divided into five groups: ADHD model, methylphenidate hydrochloride treatment (0.07 mg/mL), and low-dose (3.33 mg/mL), medium-dose (6.67 mg/mL), and high-dose (10 mg/mL) baicalin treatment (n=8 each). Eight WKY rats were selected as normal control group. Percoll density gradient centrifugation was used to prepare brain synaptosomes and an electron microscope was used to observe their structure. Colorimetry was used to measure the activities of ATPase and LDH in synaptosomes. ELISA was used to measure the content of AC, cAMP, and PKA. Compared with the normal control group, the ADHD model group had a significant reduction in the ATPase activity, a significant increase in the LDH activity, and significant reductions in the content of AC, cAMP, and PKA (PATPase activity (PATPase activity (PATPase activity (PATPase and LDH activities in rats with ADHD. The effect of baicalin is dose-dependent, and high-dose baicalin has a significantly greater effect than methylphenidate hydrochloride. Baicalin exerts its therapeutic effect possibly by upregulating the AC/cAMP/PKA signaling pathway.

  5. Smoke Signal or Smoke Screen?

    DEFF Research Database (Denmark)

    Vergne, Jean-Philippe; Wernicke, Georg; Brenner, Steffen

    This paper explains the amount of disapproval faced by firms that overpay their CEO by integrating signaling and categorization theories. We argue that, in contexts characterized by intense scrutiny, ambivalent signals sent by firms suspend categorization by stakeholders, leading to further disap...

  6. Signals and systems with MATLAB

    CERN Document Server

    Yang, Won Young; Song, Ik H; Cho, Yong S

    2009-01-01

    Covers some of the theoretical foundations and mathematical derivations that can be used in higher-level related subjects such as signal processing, communication, and control, minimizing the mathematical difficulty and computational burden. This book illustrates the usage of MATLAB and Simulink for signal and system analysis and design.

  7. Signaling equilibria in sensorimotor interactions.

    Science.gov (United States)

    Leibfried, Felix; Grau-Moya, Jordi; Braun, Daniel A

    2015-08-01

    Although complex forms of communication like human language are often assumed to have evolved out of more simple forms of sensorimotor signaling, less attention has been devoted to investigate the latter. Here, we study communicative sensorimotor behavior of humans in a two-person joint motor task where each player controls one dimension of a planar motion. We designed this joint task as a game where one player (the sender) possesses private information about a hidden target the other player (the receiver) wants to know about, and where the sender's actions are costly signals that influence the receiver's control strategy. We developed a game-theoretic model within the framework of signaling games to investigate whether subjects' behavior could be adequately described by the corresponding equilibrium solutions. The model predicts both separating and pooling equilibria, in which signaling does and does not occur respectively. We observed both kinds of equilibria in subjects and found that, in line with model predictions, the propensity of signaling decreased with increasing signaling costs and decreasing uncertainty on the part of the receiver. Our study demonstrates that signaling games, which have previously been applied to economic decision-making and animal communication, provide a framework for human signaling behavior arising during sensorimotor interactions in continuous and dynamic environments. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Noisy signaling: theory and experiment

    NARCIS (Netherlands)

    de Haan, T.; Offerman, T.; Sloof, R.

    2011-01-01

    We introduce noise in the signaling technology of an otherwise standard wasteful signaling model (Spence, 1973). We theoretically derive the properties of the equilibria under different levels of noise and we experimentally test how behavior changes with noise. We obtain three main insights. First,

  9. Signals in Communication Engineering History

    Science.gov (United States)

    Consonni, Denise; Silva, Magno T. M.

    2010-01-01

    This paper is a study of various electric signals, which have been employed throughout the history of communication engineering in its two main landmarks: the telegraph and the telephone. The signals are presented in their time and frequency domain representations. The historical order has been followed in the presentation: wired systems, spark…

  10. Non-Smad signaling pathways.

    Science.gov (United States)

    Mu, Yabing; Gudey, Shyam Kumar; Landström, Maréne

    2012-01-01

    Transforming growth factor-beta (TGFβ) is a key regulator of cell fate during embryogenesis and has also emerged as a potent driver of the epithelial-mesenchymal transition during tumor progression. TGFβ signals are transduced by transmembrane type I and type II serine/threonine kinase receptors (TβRI and TβRII, respectively). The activated TβR complex phosphorylates Smad2 and Smad3, converting them into transcriptional regulators that complex with Smad4. TGFβ also uses non-Smad signaling pathways such as the p38 and Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways to convey its signals. Ubiquitin ligase tumor necrosis factor (TNF)-receptor-associated factor 6 (TRAF6) and TGFβ-associated kinase 1 (TAK1) have recently been shown to be crucial for the activation of the p38 and JNK MAPK pathways. Other TGFβ-induced non-Smad signaling pathways include the phosphoinositide 3-kinase-Akt-mTOR pathway, the small GTPases Rho, Rac, and Cdc42, and the Ras-Erk-MAPK pathway. Signals induced by TGFβ are tightly regulated and specified by post-translational modifications of the signaling components, since they dictate the subcellular localization, activity, and duration of the signal. In this review, we discuss recent findings in the field of TGFβ-induced responses by non-Smad signaling pathways.

  11. Signal analysis of ventricular fibrillation

    NARCIS (Netherlands)

    Herbschleb, J.N.; Heethaar, R.M.; Tweel, L.H. van der; Zimmerman, A.N.E.; Meijler, F.L.

    Signal analysis of electro(cardio)grams during ventricular fibrillation (VF) in dogs and human patients indicates more organization and regularity than the official WHO definition suggests. The majority of the signal is characterized by a power spectrum with narrow, equidistant peaks. In a further

  12. Semi-classical signal analysis

    KAUST Repository

    Laleg-Kirati, Taous-Meriem; Cré peau, Emmanuelle; Sorine, Michel

    2012-01-01

    This study introduces a new signal analysis method, based on a semi-classical approach. The main idea in this method is to interpret a pulse-shaped signal as a potential of a Schrödinger operator and then to use the discrete spectrum

  13. Signaling a Change of Heart

    DEFF Research Database (Denmark)

    Schumacher, Gijs

    2011-01-01

    introduced welfare state retrenchment measures. Social Democrats can win votes and join coalitions by shifting rightwards. In contrast, they can pursue policy objectives by shifting leftwards. To communicate these shifts, in other words, ‘changes of heart’, parties send signals to voters and other parties...... after having signalled ‘a change of heart’....

  14. Intracellular signal modulation by nanomaterials.

    Science.gov (United States)

    Hussain, Salik; Garantziotis, Stavros; Rodrigues-Lima, Fernando; Dupret, Jean-Marie; Baeza-Squiban, Armelle; Boland, Sonja

    2014-01-01

    A thorough understanding of the interactions of nanomaterials with biological systems and the resulting activation of signal transduction pathways is essential for the development of safe and consumer friendly nanotechnology. Here we present an overview of signaling pathways induced by nanomaterial exposures and describe the possible correlation of their physicochemical characteristics with biological outcomes. In addition to the hierarchical oxidative stress model and a review of the intrinsic and cell-mediated mechanisms of reactive oxygen species (ROS) generating capacities of nanomaterials, we also discuss other oxidative stress dependent and independent cellular signaling pathways. Induction of the inflammasome, calcium signaling, and endoplasmic reticulum stress are reviewed. Furthermore, the uptake mechanisms can be of crucial importance for the cytotoxicity of nanomaterials and membrane-dependent signaling pathways have also been shown to be responsible for cellular effects of nanomaterials. Epigenetic regulation by nanomaterials, effects of nanoparticle-protein interactions on cell signaling pathways, and the induction of various cell death modalities by nanomaterials are described. We describe the common trigger mechanisms shared by various nanomaterials to induce cell death pathways and describe the interplay of different modalities in orchestrating the final outcome after nanomaterial exposures. A better understanding of signal modulations induced by nanomaterials is not only essential for the synthesis and design of safer nanomaterials but will also help to discover potential nanomedical applications of these materials. Several biomedical applications based on the different signaling pathways induced by nanomaterials are already proposed and will certainly gain a great deal of attraction in the near future.

  15. Algebraic Methods to Design Signals

    Science.gov (United States)

    2015-08-27

    to date on designing signals using algebraic and combinatorial methods. Mathematical tools from algebraic number theory, representation theory and... combinatorial objects in designing signals for communication purposes. Sequences and arrays with desirable autocorrelation properties have many...multiple access methods in mobile radio communication systems. We continue our mathematical framework based on group algebras, character theory

  16. Hippo signalling directs intestinal fate

    DEFF Research Database (Denmark)

    le Bouteiller, Marie Catherine M; Jensen, Kim Bak

    2015-01-01

    Hippo signalling has been associated with many important tissue functions including the regulation of organ size. In the intestinal epithelium differing functions have been proposed for the effectors of Hippo signalling, YAP and TAZ1. These are now shown to have a dual role in the intestinal...

  17. Effects of oxytocin and methacholine on cyclic nucleotide levels of rabbit myometrium.

    Science.gov (United States)

    Schlageter, N; Janis, R A; Gualtieri, R T; Hechter, O

    1980-03-01

    The effects of oxytocin and methacholine on cyclic nucleotide levels in estrogen-primed rabbit myometrium were studied in the presence and absence of 1-methyl-3-isobutyl xanthine (MIX), a phosphodiesterase inhibitor. In the absence of MIX, methacholine increased guanosine 3',5'-cyclic monophosphate (cGMP) levels at a time when contraction was decreasing, but had no influence on adenosine 3',5'-cyclic monophosphate (cAMP) levels. In contrast, oxytocin did not elevate cGMP, but rapidly decreased cAMP levels. MIX (1 mM) increased both cAMP and cGMP levels. Oxytocin or methacholine further increased cGMP, indicating activation of guanylate cyclase. Oxytocin- but not methacholine-induced stimulation of guanylate cyclase was abolished in Ca2+-free solution. Oxytocin increased cAMP over the levels produced by MIX alone, whereas methacholine decreased cAMP below the MIX control values; these effects were insensitive to indomethacin. Tissue levels of cGMP and cAMP did not directly correlate with isometric tension. The results also indicate that both oxytocin and methacholine stimulate guanylate cyclase but have opposing effects on adenylate cyclase of rabbit myometrium.

  18. Nitric oxide signalling and neuronal nitric oxide synthase in the heart under stress.

    Science.gov (United States)

    Zhang, Yin Hua

    2017-01-01

    Nitric oxide (NO) is an imperative regulator of the cardiovascular system and is a critical mechanism in preventing the pathogenesis and progression of the diseased heart. The scenario of bioavailable NO in the myocardium is complex: 1) NO is derived from both endogenous NO synthases (endothelial, neuronal, and/or inducible NOSs [eNOS, nNOS, and/or iNOS]) and exogenous sources (entero-salivary NO pathway) and the amount of NO from exogenous sources varies significantly; 2) NOSs are located at discrete compartments of cardiac myocytes and are regulated by distinctive mechanisms under stress; 3) NO regulates diverse target proteins through different modes of post-transcriptional modification (soluble guanylate cyclase [sGC]/cyclic guanosine monophosphate [cGMP]/protein kinase G [PKG]-dependent phosphorylation, S -nitrosylation, and transnitrosylation); 4) the downstream effectors of NO are multidimensional and vary from ion channels in the plasma membrane to signalling proteins and enzymes in the mitochondria, cytosol, nucleus, and myofilament; 5) NOS produces several radicals in addition to NO (e.g. superoxide, hydrogen peroxide, peroxynitrite, and different NO-related derivatives) and triggers redox-dependent responses. However, nNOS inhibits cardiac oxidases to reduce the sources of oxidative stress in diseased hearts. Recent consensus indicates the importance of nNOS protein in cardiac protection under pathological stress. In addition, a dietary regime with high nitrate intake from fruit and vegetables together with unsaturated fatty acids is strongly associated with reduced cardiovascular events. Collectively, NO-dependent mechanisms in healthy and diseased hearts are better understood and shed light on the therapeutic prospects for NO and NOSs in clinical applications for fatal human heart diseases.

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

    Science.gov (United States)

    Morales-Alamo, David; Calbet, Jose A L

    2016-09-01

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

  20. Signal processing for radiation detectors

    CERN Document Server

    Nakhostin, Mohammad

    2018-01-01

    This book provides a clear understanding of the principles of signal processing of radiation detectors. It puts great emphasis on the characteristics of pulses from various types of detectors and offers a full overview on the basic concepts required to understand detector signal processing systems and pulse processing techniques. Signal Processing for Radiation Detectors covers all of the important aspects of signal processing, including energy spectroscopy, timing measurements, position-sensing, pulse-shape discrimination, and radiation intensity measurement. The book encompasses a wide range of applications so that readers from different disciplines can benefit from all of the information. In addition, this resource: * Describes both analog and digital techniques of signal processing * Presents a complete compilation of digital pulse processing algorithms * Extrapolates content from more than 700 references covering classic papers as well as those of today * Demonstrates concepts with more than 340 origin...

  1. Aberrant Signaling Pathways in Glioma

    International Nuclear Information System (INIS)

    Nakada, Mitsutoshi; Kita, Daisuke; Watanabe, Takuya; Hayashi, Yutaka; Teng, Lei; Pyko, Ilya V.; Hamada, Jun-Ichiro

    2011-01-01

    Glioblastoma multiforme (GBM), a WHO grade IV malignant glioma, is the most common and lethal primary brain tumor in adults; few treatments are available. Median survival rates range from 12–15 months. The biological characteristics of this tumor are exemplified by prominent proliferation, active invasiveness, and rich angiogenesis. This is mainly due to highly deregulated signaling pathways in the tumor. Studies of these signaling pathways have greatly increased our understanding of the biology and clinical behavior of GBM. An integrated view of signal transduction will provide a more useful approach in designing novel therapies for this devastating disease. In this review, we summarize the current understanding of GBM signaling pathways with a focus on potential molecular targets for anti-signaling molecular therapies

  2. Quorum Quenching Revisited—From Signal Decays to Signalling Confusion

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2012-04-01

    Full Text Available In a polymicrobial community, while some bacteria are communicating with neighboring cells (quorum sensing, others are interrupting the communication (quorum quenching, thus creating a constant arms race between intercellular communication. In the past decade, numerous quorum quenching enzymes have been found and initially thought to inactivate the signalling molecules. Though this is widely accepted, the actual roles of these quorum quenching enzymes are now being uncovered. Recent evidence extends the role of quorum quenching to detoxification or metabolism of signalling molecules as food and energy source; this includes “signalling confusion”, a term coined in this paper to refer to the phenomenon of non-destructive modification of signalling molecules. While quorum quenching has been explored as a novel anti-infective therapy targeting, quorum sensing evidence begins to show the development of resistance against quorum quenching.

  3. Alternatives to Pyrotechnic Distress Signals; Additional Signal Evaluation

    Science.gov (United States)

    2017-06-01

    device performance standard that addresses Coast Guard project sponsor and stakeholders needs. 17. Key Words Visual Distress Signal Device (VDSD...devices. The report discussed the concept of “effective intensity,” as used by the International Association of Marine Aids to Navigation and Lighthouse...efficacy of Cyan as a signal color. In order to move forward, the RDC project team met with CG-ENG-4 and other Coast Guard stakeholders (Offices of

  4. Fast digitizing and digital signal processing of detector signals

    International Nuclear Information System (INIS)

    Hannaske, Roland

    2008-01-01

    A fast-digitizer data acquisition system recently installed at the neutron time-of-flight experiment nELBE, which is located at the superconducting electron accelerator ELBE of Forschungszentrum Dresden-Rossendorf, is tested with two different detector types. Preamplifier signals from a high-purity germanium detector are digitized, stored and finally processed. For a precise determination of the energy of the detected radiation, the moving-window deconvolution algorithm is used to compensate the ballistic deficit and different shaping algorithms are applied. The energy resolution is determined in an experiment with γ-rays from a 22 Na source and is compared to the energy resolution achieved with analogously processed signals. On the other hand, signals from the photomultipliers of barium fluoride and plastic scintillation detectors are digitized. These signals have risetimes of a few nanoseconds only. The moment of interaction of the radiation with the detector is determined by methods of digital signal processing. Therefore, different timing algorithms are implemented and tested with data from an experiment at nELBE. The time resolutions achieved with these algorithms are compared to each other as well as to reference values coming from analog signal processing. In addition to these experiments, some properties of the digitizing hardware are measured and a program for the analysis of stored, digitized data is developed. The analysis of the signals shows that the energy resolution achieved with the 10-bit digitizer system used here is not competitive to a 14-bit peak-sensing ADC, although the ballistic deficit can be fully corrected. However, digital methods give better result in sub-ns timing than analog signal processing. (orig.)

  5. Advanced optical signal processing of broadband parallel data signals

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Hu, Hao; Kjøller, Niels-Kristian

    2016-01-01

    Optical signal processing may aid in reducing the number of active components in communication systems with many parallel channels, by e.g. using telescopic time lens arrangements to perform format conversion and allow for WDM regeneration.......Optical signal processing may aid in reducing the number of active components in communication systems with many parallel channels, by e.g. using telescopic time lens arrangements to perform format conversion and allow for WDM regeneration....

  6. ESR signals of irradiated insects

    International Nuclear Information System (INIS)

    Ukai, Mitsuko; Kameya, Hiromi; Imamura, Taro; Miyanoshita, Akihiro; Todoriki, Setsuko; Shimoyama, Yuhei

    2009-01-01

    Analysis of irradiated insects using Electron Spin Resonance (ESR) spectroscopy was reported. The insects were maize weevil, red flour beetle, Indian meal moth and cigarette beetle that are hazardous to crops. The ESR spectra were consisted of a singlet at g=2 and a sextet centered at the similar g-value. The singlet signal is due to an organic free radical. The sextet signal is attributable to the hyperfine interactions from Mn 2+ ions. Upon irradiation, new signals were not detected. The relaxation times, T 1 and T 2 , showed no variations before and after irradiation. (author)

  7. Statistical theory of signal detection

    CERN Document Server

    Helstrom, Carl Wilhelm; Costrell, L; Kandiah, K

    1968-01-01

    Statistical Theory of Signal Detection, Second Edition provides an elementary introduction to the theory of statistical testing of hypotheses that is related to the detection of signals in radar and communications technology. This book presents a comprehensive survey of digital communication systems. Organized into 11 chapters, this edition begins with an overview of the theory of signal detection and the typical detection problem. This text then examines the goals of the detection system, which are defined through an analogy with the testing of statistical hypotheses. Other chapters consider

  8. Subjective Evaluation of Audiovisual Signals

    Directory of Open Access Journals (Sweden)

    F. Fikejz

    2010-01-01

    Full Text Available This paper deals with subjective evaluation of audiovisual signals, with emphasis on the interaction between acoustic and visual quality. The subjective test is realized by a simple rating method. The audiovisual signal used in this test is a combination of images compressed by JPEG compression codec and sound samples compressed by MPEG-1 Layer III. Images and sounds have various contents. It simulates a real situation when the subject listens to compressed music and watches compressed pictures without the access to original, i.e. uncompressed signals.

  9. On Generalized Fractional Differentiator Signals

    Directory of Open Access Journals (Sweden)

    Hamid A. Jalab

    2013-01-01

    Full Text Available By employing the generalized fractional differential operator, we introduce a system of fractional order derivative for a uniformly sampled polynomial signal. The calculation of the bring in signal depends on the additive combination of the weighted bring-in of N cascaded digital differentiators. The weights are imposed in a closed formula containing the Stirling numbers of the first kind. The approach taken in this work is to consider that signal function in terms of Newton series. The convergence of the system to a fractional time differentiator is discussed.

  10. Antidepressant-like properties of sildenafil in a genetic rat model of depression: Role of cholinergic cGMP-interactions

    DEFF Research Database (Denmark)

    Liebenberg, Nico; Brink, Christiaan; Brand, Linda

    2008-01-01

    Background: The N-methyl-D-aspartate (NMDA)/nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway has been implicated in the neurobiology of depression. Recently we suggested a possible complex interaction between the cholinergic and NO-cGMP pathways in the antidepressant-like response....... Conclusions: Using a genetic animal model of depression, we have confirmed the antidepressant-like property of sildenafil following “unmasking” by concomitant block of muscarinic receptors. These findings hint at a novel interaction between the cGMP and cholinergic systems in depression, and suggest...

  11. Nitroso-sulfide coupled signaling triggers specific vasoactive effects in the intrarenal arteries of patients with arterial hypertension.

    Science.gov (United States)

    Cacanyiova, S; Berenyiova, A; Balis, P; Kristek, F; Grman, M; Ondrias, K; Breza, J; Breza, J

    2017-08-01

    In normotensive conditions, it has been confirmed that S-nitrosothiols (RSNO), can interact with hydrogen sulfide (H 2 S) and create new substances with specific vasoactive effects. This interaction could also represent a new regulator signaling pathway in conditions of hypertension. Until now, these effects were studied only in normotensive rats, and they have not been carried out in humans yet. We investigated the vasoactive effects of the products of the H 2 S/S-nitrosoglutathione (S/GSNO) interaction in lobar arteries (LA) isolated from the nephrectomized kidneys of patients suffering from arterial hypertension and in renal arteries (RA) of spontaneously hypertensive rats (SHR). The changes in the isometric tension of pre-contracted arteries were evaluated. Acetylcholine-induced vasorelaxation of LA was reduced compared to the effect induced by an NO donor, sodium nitroprusside suggesting an endothelium dysfunction. While 1 μmol/L Na2S had a minimal effect on the vascular tone, the concentration 20 μmol/L evoked a slight vasorelaxation. GSNO at 0.1 μmol/L induced vasorelaxation, which was less pronounced compared to the effect induced by 1 μmol/L. The S/GSNO products (final concentration 0.1 μmol/L) prepared as the mixture of GSNO (0.1 μmol/L) + Na2S (1 μmol/L) induced a higher vasorelaxation compared to GSNO (0.1 μmol/L) alone only in the 5 th minute and without the differences in the speed. On the other hand, the S/GSNO products (final concentration 1 μmol/L) prepared as the mixture of GSNO (1 μmol/L) + Na2S (10 μmol/L) induced a higher and faster vasorelaxation compared to the effect induced by GSNO (1 μmol/L) alone. In RA of SHR this S/GSNO products induced similar vasorelaxation (higher and faster than GSNO) with involvement of HNO (partially) and cGMP as mediators. However, the products of the H 2 S/NO donor (DEA NONOate) manifested differently than S/GSNO indicating the unique interaction between GSNO and H 2 S. In this study, we confirmed

  12. Ultrasound imaging using coded signals

    DEFF Research Database (Denmark)

    Misaridis, Athanasios

    Modulated (or coded) excitation signals can potentially improve the quality and increase the frame rate in medical ultrasound scanners. The aim of this dissertation is to investigate systematically the applicability of modulated signals in medical ultrasound imaging and to suggest appropriate...... methods for coded imaging, with the goal of making better anatomic and flow images and three-dimensional images. On the first stage, it investigates techniques for doing high-resolution coded imaging with improved signal-to-noise ratio compared to conventional imaging. Subsequently it investigates how...... coded excitation can be used for increasing the frame rate. The work includes both simulated results using Field II, and experimental results based on measurements on phantoms as well as clinical images. Initially a mathematical foundation of signal modulation is given. Pulse compression based...

  13. Digital storage of repeated signals

    International Nuclear Information System (INIS)

    Prozorov, S.P.

    1984-01-01

    An independent digital storage system designed for repeated signal discrimination from background noises is described. The signal averaging is performed off-line in the real time mode by means of multiple selection of the investigated signal and integration in each point. Digital values are added in a simple summator and the result is recorded the storage device with the volume of 1024X20 bit from where it can be output on an oscillograph, a plotter or transmitted to a compUter for subsequent processing. The described storage is reliable and simple device on one base of which the systems for the nuclear magnetic resonapce signal acquisition in different experiments are developed

  14. Zufällige Signale

    Science.gov (United States)

    Plaßmann, Wilfried

    Die hier betrachteten Signale werden auch als stochastische Signale bezeichnet. Sie sind zufällig, d. h. ihr Augenblickswert ist nicht vorhersagbar. Abb. 118.1 zeigt eine Unterteilung nach den Signaleigenschaften. Über die nichtstationären Signale lässt sich keinerlei Aussage machen, und sie werden hier deshalb auch nicht weiter betrachtet. Für die stationären Signale gilt, dass ihr Momentanwert zwar auch nicht vorhergesagt werden kann, dass sie aber trotzdem gewisse auswertbare Eigenschaften besitzen, die allerdings statistischer Art sind und deshalb nur mit den Gesetzen der Wahrscheinlichkeitstheorie erfasst werden können. Zwar sind - theoretisch - für die Anwendung der Wahrscheinlichkeitstheorie unendlich viele Probenwerte zu nehmen, in der Praxis hat sich aber gezeigt, dass man auch mit einer endlichen Anzahl dem gesuchten Wert schon ausreichend nahe kommen kann.

  15. Signal Incongruence and its Consequences

    DEFF Research Database (Denmark)

    Vergne, Jean-Philippe; Wernicke, Maria Stokholm; Brenner, Steffen

    2018-01-01

    theory on signal incongruence, we find that firms engaged in philanthropy receive more media disapproval when they overcompensate their CEO, but they are also more likely to decrease CEO overcompensation as a response. Our study contributes to the signaling literature by theorizing about signal......We draw on the signaling and infomediary literatures to examine how media evaluations of CEO overcompensation (a negative cue associated with selfishness and greed) are affected by the presence of corporate philanthropy (a positive cue associated with altruism and generosity). In line with our...... incongruence, and to infomediary and corporate governance research by showing that media disapproval can lead to lower executive compensation. We also reconcile two conflicting views on firm prosocial behavior by showing that, in the presence of incongruent cues, philanthropy can simultaneously enhance...

  16. Mathematical Modelling Plant Signalling Networks

    KAUST Repository

    Muraro, D.; Byrne, H.M.; King, J.R.; Bennett, M.J.

    2013-01-01

    methods for modelling gene and signalling networks and their application in plants. We then describe specific models of hormonal perception and cross-talk in plants. This mathematical analysis of sub-cellular molecular mechanisms paves the way for more

  17. Signal transforms in dynamic measurements

    CERN Document Server

    Layer, Edward

    2015-01-01

    This book is devoted to the analysis of measurement signals which requires specific mathematical operations like Convolution, Deconvolution, Laplace, Fourier, Hilbert, Wavelet or Z transform which are all presented in the present book. The different problems refer to the modulation of signals, filtration of disturbance as well as to the orthogonal signals and their use in digital form for the measurement of current, voltage, power and frequency are also widely discussed. All the topics covered in this book are presented in detail and illustrated by means of examples in MathCad and LabVIEW. This book provides a useful source for researchers, scientists and engineers who in their daily work are required to deal with problems of measurement and signal processing and can also be helpful to undergraduate students of electrical engineering.    

  18. Dopamine signaling: target in glioblastoma

    Czech Academy of Sciences Publication Activity Database

    Bartek, Jiří; Hodný, Zdeněk

    2014-01-01

    Roč. 5, č. 5 (2014), 1116-1117 ISSN 1949-2553 Institutional support: RVO:68378050 Keywords : Dopamine signaling * glioblastoma * MAPK Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.359, year: 2014

  19. Pedestrian Friendly Traffic Signal Control.

    Science.gov (United States)

    2016-01-01

    This project continues research aimed at real-time detection and use of pedestrian : traffic flow information to enhance adaptive traffic signal control in urban areas : where pedestrian traffic is substantial and must be given appropriate attention ...

  20. Nuclear Receptor Signaling Atlas (NURSA)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Nuclear Receptor Signaling Atlas (NURSA) is designed to foster the development of a comprehensive understanding of the structure, function, and role in disease...

  1. Essential roles of insulin, AMPK signaling and lysyl and prolyl hydroxylases in the biosynthesis and multimerization of adiponectin.

    Science.gov (United States)

    Zhang, Lin; Li, Ming-Ming; Corcoran, Marie; Zhang, Shaoping; Cooper, Garth J S

    2015-01-05

    Post-translational modifications (PTMs) of the adiponectin molecule are essential for its full bioactivity, and defects in PTMs leading to its defective production and multimerization have been linked to the mechanisms of insulin resistance, obesity, and type-2 diabetes. Here we observed that, in differentiated 3T3-L1 adipocytes, decreased insulin signaling caused by blocking of insulin receptors (InsR) with an anti-InsR blocking antibody, increased rates of adiponectin secretion, whereas concomitant elevations in insulin levels counteracted this effect. Adenosine monophosphate-activated protein kinase (AMPK) signaling regulated adiponectin production by modulating the expression of adiponectin receptors, the secretion of adiponectin, and eventually the expression of adiponectin itself. We found that lysyl hydroxylases (LHs) and prolyl hydroxylases (PHs) were expressed in white-adipose tissue of ob/ob mice, wherein LH3 levels were increased compared with controls. In differentiated 3T3-L1 adipocytes, both non-specific inhibition of LHs and PHs by dipyridyl, and specific inhibition of LHs by minoxidil and of P4H with ethyl-3,4-dihydroxybenzoate, caused significant suppression of adiponectin production, more particularly of the higher-order isoforms. Transient gene knock-down of LH3 (Plod3) caused a suppressive effect, especially on the high molecular-weight (HMW) isoforms. These data indicate that PHs and LHs are both required for physiological adiponectin production and in particular are essential for the formation/secretion of the HMW isoforms. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. The Neuroprotective Effect of Curcumin Against Nicotine-Induced Neurotoxicity is Mediated by CREB-BDNF Signaling Pathway.

    Science.gov (United States)

    Motaghinejad, Majid; Motevalian, Manijeh; Fatima, Sulail; Faraji, Fahimeh; Mozaffari, Shiva

    2017-10-01

    Nicotine abuse adversely affects brain and causes apoptotic neurodegeneration. Curcumin- a bright yellow chemical compound found in turmeric is associated with neuroprotective properties. The current study was designed to evaluate the role of CREB-BDNF signaling in mediating the neuroprotective effects of curcumin against nicotine-induced apoptosis, oxidative stress and inflammation in rats. Sixty adult male rats were divided randomly into six groups. Group 1 received 0.7 ml/rat normal saline, group 2 received 6 mg/kg nicotine. Groups 3, 4, 5 and 6 were treated concurrently with nicotine (6 mg/kg) and curcumin (10, 20, 40 and 60 mg/kg i.p. respectively) for 21 days. Open Field Test (OFT) was used to evaluate the motor activity. Hippocampal oxidative, anti-oxidant, inflammatory and apoptotic factors were evaluated. Furthermore, phosphorylated brain cyclic adenosine monophosphate (cAMP) response element binding protein (P-CREB) and brain derived neurotrophic factor (BDNF) levels were studied at gene and protein levels. We found that nicotine disturbed the motor activity in OFT and simultaneous treatment with curcumin (40 and 60 mg/kg) reduced the nicotine-induced motor activity disturbances. In addition, nicotine treatment increased lipid peroxidation and the levels of GSH, IL-1β, TNF-α and Bax, while reducing Bcl-2, P-CREB and BDNF levels in the hippocampus. Nicotine also reduced the activity of superoxide dismutase, glutathione peroxidase and glutathione reductase in hippocampus. In contrast, various doses of curcumin attenuated nicotine-induced apoptosis, oxidative stress and inflammation; while elevating P-CREB and BDNF levels. Thus, curcumin via activation of P-CREB/BDNF signaling pathway, confers neuroprotection against nicotine-induced inflammation, apoptosis and oxidative stress.

  3. SAD-A kinase controls islet β-cell size and function as a mediator of mTORC1 signaling.

    Science.gov (United States)

    Nie, Jia; Liu, Xiaolei; Lilley, Brendan N; Zhang, Hai; Pan, Y Albert; Kimball, Scot R; Zhang, Jun; Zhang, Weiping; Wang, Li; Jefferson, Leonard S; Sanes, Joshua R; Han, Xiao; Shi, Yuguang

    2013-08-20

    The mammalian target of rapamycin (mTOR) plays an important role in controlling islet β-cell function. However, the underlying molecular mechanisms remain poorly elucidated. Synapses of amphids defective kinase-A (SAD-A) is a 5' adenosine monophosphate-activated protein kinase-related protein kinase that is exclusively expressed in pancreas and brain. In this study, we investigated a role of the kinase in regulating pancreatic β-cell morphology and function as a mediator of mTOR complex 1 (mTORC1) signaling. We show that global SAD-A deletion leads to defective glucose-stimulated insulin secretion and petite islets, which are reminiscent of the defects in mice with global deletion of ribosomal protein S6 kinase 1, a downstream target of mTORC1. Consistent with these findings, selective deletion of SAD-A in pancreas decreased islet β-cell size, whereas SAD-A overexpression significantly increased the size of mouse insulinomas cell lines β-cells. In direct support of SAD-A as a unique mediator of mTORC1 signaling in islet β-cells, we demonstrate that glucose dramatically stimulated SAD-A protein translation in isolated mouse islets, which was potently inhibited by rapamycin, an inhibitor of mTORC1. Moreover, the 5'-untranslated region of SAD-A mRNA is highly structured and requires mTORC1 signaling for its translation initiation. Together, these findings identified SAD-A as a unique pancreas-specific effector protein of mTORC1 signaling.

  4. Intercellular signalling in Stigmatella aurantiaca.

    Science.gov (United States)

    Plaga, W; Ulrich, S H

    1999-12-01

    The myxobacterium Stigmatella aurantiaca is a prokaryotic model used to study intercellular signalling and the genetic determination of morphogenesis. Signalling factors and genes required for the generation of the elaborate multicellular fruiting body are to be identified. Recently, the structure of stigmolone, which is the pheromone necessary for fruiting body formation, was elucidated, and genes involved in development were characterised. Progress has also been made in the genetic accessibility of S. aurantiaca.

  5. Neurotransmitter signaling in white matter.

    Science.gov (United States)

    Butt, Arthur M; Fern, Robert F; Matute, Carlos

    2014-11-01

    White matter (WM) tracts are bundles of myelinated axons that provide for rapid communication throughout the CNS and integration in grey matter (GM). The main cells in myelinated tracts are oligodendrocytes and astrocytes, with small populations of microglia and oligodendrocyte precursor cells. The prominence of neurotransmitter signaling in WM, which largely exclude neuronal cell bodies, indicates it must have physiological functions other than neuron-to-neuron communication. A surprising aspect is the diversity of neurotransmitter signaling in WM, with evidence for glutamatergic, purinergic (ATP and adenosine), GABAergic, glycinergic, adrenergic, cholinergic, dopaminergic and serotonergic signaling, acting via a wide range of ionotropic and metabotropic receptors. Both axons and glia are potential sources of neurotransmitters and may express the respective receptors. The physiological functions of neurotransmitter signaling in WM are subject to debate, but glutamate and ATP-mediated signaling have been shown to evoke Ca(2+) signals in glia and modulate axonal conduction. Experimental findings support a model of neurotransmitters being released from axons during action potential propagation acting on glial receptors to regulate the homeostatic functions of astrocytes and myelination by oligodendrocytes. Astrocytes also release neurotransmitters, which act on axonal receptors to strengthen action potential propagation, maintaining signaling along potentially long axon tracts. The co-existence of multiple neurotransmitters in WM tracts suggests they may have diverse functions that are important for information processing. Furthermore, the neurotransmitter signaling phenomena described in WM most likely apply to myelinated axons of the cerebral cortex and GM areas, where they are doubtless important for higher cognitive function. © 2014 Wiley Periodicals, Inc.

  6. Sentiment analysis for PTSD signals

    CERN Document Server

    Kagan, Vadim; Sapounas, Demetrios

    2013-01-01

    This book describes a computational framework for real-time detection of psychological signals related to Post-Traumatic Stress Disorder (PTSD) in online text-based posts, including blogs and web forums. Further, it explores how emerging computational techniques such as sentiment mining can be used in real-time to identify posts that contain PTSD-related signals, flag those posts, and bring them to the attention of psychologists, thus providing an automated flag and referral capability.

  7. Aberrant Wnt Signaling in Leukemia

    Directory of Open Access Journals (Sweden)

    Frank J. T. Staal

    2016-08-01

    Full Text Available The Wnt signaling pathway is essential in the development and homeostasis of blood and immune cells, but its exact role is still controversial and is the subject of intense research. The malignant counterpart of normal hematopoietic cells, leukemic (stem cells, have hijacked the Wnt pathway for their self-renewal and proliferation. Here we review the multiple ways dysregulated Wnt signaling can contribute to leukemogenesis, both cell autonomously as well as by changes in the microenvironment.

  8. Wnt signaling in limb organogenesis

    OpenAIRE

    Geetha-Loganathan, Poongodi; Nimmagadda, Suresh; Scaal, Martin

    2008-01-01

    Secreted signaling molecules of the Wnt family have been found to play a central role in controlling embryonic development of a wide range of taxa from Hydra to humans. The most extensively studied Wnt signaling pathway is the canonical Wnt pathway, which controls gene expression by stabilizing β-catenin, and regulates a multitude of developmental processes. More recently, noncanonical Wnt pathways, which are β-catenin-independent, have been found to be important developmental regulators. Und...

  9. Handbook of signal processing systems

    CERN Document Server

    Deprettere, Ed; Leupers, Rainer; Takala, Jarmo

    2013-01-01

    Handbook of Signal Processing Systems is organized in three parts. The first part motivates representative applications that drive and apply state-of-the art methods for design and implementation of signal processing systems; the second part discusses architectures for implementing these applications; the third part focuses on compilers and simulation tools, describes models of computation and their associated design tools and methodologies. This handbook is an essential tool for professionals in many fields and researchers of all levels.

  10. Hedgehog Signaling in Endochondral Ossification

    Directory of Open Access Journals (Sweden)

    Shinsuke Ohba

    2016-06-01

    Full Text Available Hedgehog (Hh signaling plays crucial roles in the patterning and morphogenesis of various organs within the bodies of vertebrates and insects. Endochondral ossification is one of the notable developmental events in which Hh signaling acts as a master regulator. Among three Hh proteins in mammals, Indian hedgehog (Ihh is known to work as a major Hh input that induces biological impact of Hh signaling on the endochondral ossification. Ihh is expressed in prehypertrophic and hypertrophic chondrocytes of developing endochondral bones. Genetic studies so far have demonstrated that the Ihh-mediated activation of Hh signaling synchronizes chondrogenesis and osteogenesis during endochondral ossification by regulating the following processes: (1 chondrocyte differentiation; (2 chondrocyte proliferation; and (3 specification of bone-forming osteoblasts. Ihh not only forms a negative feedback loop with parathyroid hormone-related protein (PTHrP to maintain the growth plate length, but also directly promotes chondrocyte propagation. Ihh input is required for the specification of progenitors into osteoblast precursors. The combinatorial approaches of genome-wide analyses and mouse genetics will facilitate understanding of the regulatory mechanisms underlying the roles of Hh signaling in endochondral ossification, providing genome-level evidence of the potential of Hh signaling for the treatment of skeletal disorders.

  11. Hedgehog Signaling in Endochondral Ossification

    Science.gov (United States)

    Ohba, Shinsuke

    2016-01-01

    Hedgehog (Hh) signaling plays crucial roles in the patterning and morphogenesis of various organs within the bodies of vertebrates and insects. Endochondral ossification is one of the notable developmental events in which Hh signaling acts as a master regulator. Among three Hh proteins in mammals, Indian hedgehog (Ihh) is known to work as a major Hh input that induces biological impact of Hh signaling on the endochondral ossification. Ihh is expressed in prehypertrophic and hypertrophic chondrocytes of developing endochondral bones. Genetic studies so far have demonstrated that the Ihh-mediated activation of Hh signaling synchronizes chondrogenesis and osteogenesis during endochondral ossification by regulating the following processes: (1) chondrocyte differentiation; (2) chondrocyte proliferation; and (3) specification of bone-forming osteoblasts. Ihh not only forms a negative feedback loop with parathyroid hormone-related protein (PTHrP) to maintain the growth plate length, but also directly promotes chondrocyte propagation. Ihh input is required for the specification of progenitors into osteoblast precursors. The combinatorial approaches of genome-wide analyses and mouse genetics will facilitate understanding of the regulatory mechanisms underlying the roles of Hh signaling in endochondral ossification, providing genome-level evidence of the potential of Hh signaling for the treatment of skeletal disorders. PMID:29615586

  12. Metabolites in vertebrate Hedgehog signaling.

    Science.gov (United States)

    Roberg-Larsen, Hanne; Strand, Martin Frank; Krauss, Stefan; Wilson, Steven Ray

    2014-04-11

    The Hedgehog (HH) signaling pathway is critical in embryonic development, stem cell biology, tissue homeostasis, chemoattraction and synapse formation. Irregular HH signaling is associated with a number of disease conditions including congenital disorders and cancer. In particular, deregulation of HH signaling has been linked to skin, brain, lung, colon and pancreatic cancers. Key mediators of the HH signaling pathway are the 12-pass membrane protein Patched (PTC), the 7-pass membrane protein Smoothened (SMO) and the GLI transcription factors. PTC shares homology with the RND family of small-molecule transporters and it has been proposed that it interferes with SMO through metabolites. Although a conclusive picture is lacking, substantial efforts are made to identify and understand natural metabolites/sterols, including cholesterol, vitamin D3, oxysterols and glucocorticoides, that may be affected by, or influence the HH signaling cascade at the level of PTC and SMO. In this review we will elaborate the role of metabolites in HH signaling with a focus on oxysterols, and discuss advancements in modern analytical approaches in the field. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. 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.

  14. Insulin Signaling and Heart Failure

    Science.gov (United States)

    Riehle, Christian; Abel, E. Dale

    2016-01-01

    Heart failure is associated with generalized insulin resistance. Moreover, insulin resistant states such as type 2 diabetes and obesity increases the risk of heart failure even after adjusting for traditional risk factors. Insulin resistance or type 2 diabetes alters the systemic and neurohumoral milieu leading to changes in metabolism and signaling pathways in the heart that may contribute to myocardial dysfunction. In addition, changes in insulin signaling within cardiomyocytes develop in the failing heart. The changes range from activation of proximal insulin signaling pathways that may contribute to adverse left ventricular remodeling and mitochondrial dysfunction to repression of distal elements of insulin signaling pathways such as forkhead (FOXO) transcriptional signaling or glucose transport which may also impair cardiac metabolism, structure and function. This article will review the complexities of insulin signaling within the myocardium and ways in which these pathways are altered in heart failure or in conditions associated with generalized insulin resistance. The implications of these changes for therapeutic approaches to treating or preventing heart failure will be discussed. PMID:27034277

  15. Cyclic AMP-dependent signaling system is a primary metabolic target for non-thermal effect of microwaves on heart muscle hydration.

    Science.gov (United States)

    Narinyan, Lilia; Ayrapetyan, Sinerik

    2017-01-01

    Previously, we have suggested that cell hydration is a universal and extra-sensitive sensor for the structural changes of cell aqua medium caused by the impact of weak chemical and physical factors. The aim of present work is to elucidate the nature of the metabolic messenger through which physiological solution (PS) treated by non-thermal (NT) microwaves (MW) could modulate heart muscle hydration of rats. For this purpose, the effects of NT MW-treated PS on heart muscle hydration, [ 3 H]-ouabain binding with cell membrane, 45 Ca 2+ uptake and intracellular cyclic nucleotides contents in vivo and in vitro experiments were studied. It is shown that intraperitoneal injections of both Sham-treated PS and NT MW-treated PS elevate heart muscle hydration. However, the effect of NT MW-treated PS on muscle hydration is more pronounced than the effect of Sham-treated PS. In vitro experiments NT MW-treated PS has dehydration effect on muscle, which is not changed by decreasing Na + gradients on membrane. Intraperitoneal injection of Sham- and NT MW-treated PS containing 45 Ca 2+ have similar dehydration effect on muscle, while NT MW-treated PS has activation effect on Na + /Ca 2+ exchange in reverse mode. The intraperitoneal injection of NT MW-treated PS depresses [ 3 H]-ouabain binding with its high-affinity membrane receptors, elevates intracellular cAMP and decreases cGMP contents. Based on the obtained data, it is suggested that cAMP-dependent signaling system serves as a primary metabolic target for NT MW effect on heart muscle hydration.

  16. Estrogen Receptor Signaling and the PI3K/Akt Pathway Are Involved in Betulinic Acid-Induced eNOS Activation

    Directory of Open Access Journals (Sweden)

    Nicolas Hohmann

    2016-07-01

    Full Text Available Betulinic acid (BA is a naturally occurring pentacyclic triterpenoid with anti-inflammatory, antiviral and anti-cancer properties. Beneficial cardiovascular effects such as increased nitric oxide (NO production through enhancement of endothelial NO synthase (eNOS activity and upregulation of eNOS expression have been demonstrated for this compound. In the present study, immortalized human EA.hy 926 endothelial cells were incubated for up to 1 h with 1–100 µM BA and with the phosphatidylinositol-3-kinase (PI3K inhibitors LY294002 and wortmannin, or the estrogen receptor (ER antagonist ICI 182,780. Phosphorylation status of eNOS and total eNOS protein were analyzed by Western blotting using a serine 1177 phosphosite-specific antibody. Bioactive NO production was assessed by determination of cGMP content in rat lung fibroblasts (RFL-6 reporter cells. Short-term incubation of EA.hy 926 cells with BA resulted in eNOS phosphorylation at the serine 1177 residue in a concentration- and time-dependent manner with a half-maximal effective concentration of 0.57 µM. This was associated with an enhanced production of NO. BA-induced eNOS phosphorylation and NO production was completely blocked by pretreatment with ICI 182,780, and was attenuated by pretreatment with the PI3K inhibitors wortmannin and LY294002. These results indicate that fast non-genomic effects of ER with downstream signaling through the PI3K/Akt pathway and consecutive eNOS phosphorylation at serine 1177 are involved in BA-induced eNOS activation.

  17. SignalPlant: an open signal processing software platform.

    Science.gov (United States)

    Plesinger, F; Jurco, J; Halamek, J; Jurak, P

    2016-07-01

    The growing technical standard of acquisition systems allows the acquisition of large records, often reaching gigabytes or more in size as is the case with whole-day electroencephalograph (EEG) recordings, for example. Although current 64-bit software for signal processing is able to process (e.g. filter, analyze, etc) such data, visual inspection and labeling will probably suffer from rather long latency during the rendering of large portions of recorded signals. For this reason, we have developed SignalPlant-a stand-alone application for signal inspection, labeling and processing. The main motivation was to supply investigators with a tool allowing fast and interactive work with large multichannel records produced by EEG, electrocardiograph and similar devices. The rendering latency was compared with EEGLAB and proves significantly faster when displaying an image from a large number of samples (e.g. 163-times faster for 75  ×  10(6) samples). The presented SignalPlant software is available free and does not depend on any other computation software. Furthermore, it can be extended with plugins by third parties ensuring its adaptability to future research tasks and new data formats.

  18. A common signaling pathway is activated in erythroid cells expressing high levels of fetal hemoglobin: a potential role for cAMP-elevating agents in β-globin disorders

    Directory of Open Access Journals (Sweden)

    Ikuta T

    2013-12-01

    Full Text Available Tohru Ikuta,1 Yuichi Kuroyanagi,1 Nadine Odo,1 Siyang Liu21Department of Anesthesiology and Perioperative Medicine, 2Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, GA, USABackground: Although erythroid cells prepared from fetal liver, cord blood, or blood from β-thalassemia patients are known to express fetal hemoglobin at high levels, the underlying mechanisms remain elusive. We previously showed that cyclic nucleotides such as cAMP and cGMP induce fetal hemoglobin expression in primary erythroid cells. Here we report that cAMP signaling contributes to high-level fetal hemoglobin expression in erythroid cells prepared from cord blood and β-thalassemia.Methods: The status of the cAMP signaling pathway was investigated using primary erythroid cells prepared from cord blood and the mononuclear cells of patients with β-thalassemia; erythroid cells from adult bone marrow mononuclear cells served as the control.Results: We found that intracellular cAMP levels were higher in erythroid cells from cord blood and β-thalassemia than from adult bone marrow. Protein kinase A activity levels and cAMP-response element binding protein phosphorylation were higher in erythroid cells from cord blood or β-thalassemia than in adult bone marrow progenitors. Mitogen-activated protein kinase pathways, which play a role in fetal hemoglobin expression, were not consistently activated in cord blood or β-thalassemia erythroid cells. When cAMP signaling was activated in adult erythroid cells, fetal hemoglobin was induced at high levels and associated with reduced expression of BCL11A, a silencer of the β-globin gene.Conclusion: These results suggest that activated cAMP signaling may be a common mechanism among erythroid cells with high fetal hemoglobin levels, in part because of downregulation of BCL11A. Activation of the cAMP signaling pathway with cAMP-elevating agents may prove to be an important signaling mechanism to

  19. 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

  20. Heme oxygenase-1 and abscisic acid effects MAPK´s gene expression in soybean seeds

    International Nuclear Information System (INIS)

    Giacometti, R.; Santa Cruz, D.; Noriega, G.; Balestrasse, K.

    2012-01-01

    In soybean previous studies enabled the identification of MAPK3 and 6 whose activity is enhanced within the signaling pathway leading to defense reactions. In this study the effects of different compounds related to hemeoxygenase (HO-1) biosynthesis on mitogen-activated protein kinase (MAPK’s) genes expression in soybean seeds were tested. To this end, 20μM hemine, 22μM ZnPPIX, 0.5mM furidine or 100μM 8-bromoguanosine 3',5'-cyclic monophosphate (8Br) were added to pre-hydrated seeds for 5 days. MAPK’s genes expression was enhanced in seeds treated with hemine. This result indicates that heme catabolism could be involved in the signaling mediated by this cascade pathway. To confirm this hypothesis experiments were carried out in the precsence of ZnPPIX, a potent irreversible HO-1 inhibitor. In this case, no gene induction was observed. On the other hand, 8Br, a cGMP analog, induced HO-1 gene expression but did not modulate MAPK’s, indicating that this effect could not be mediated by cGMP. When the action of furidine, an abscisic acid inhibitor, was tested a diminution of HO-1 gene expression was observed. In this regard, MAPK’s showed a different response, being MAPK6 the only transcript that showed a diminished respect to controls, while MAPK3 mRNA as well as MAPKK1 was enhanced. These results were confirmed by western blotting and activity determinations. (authors)