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Sample records for specific electronic signal

  1. Highly specific electronic signal transduction mediated by DNA/metal self-assembly.

    SciTech Connect

    Dentinger, Paul M.; Pathak, Srikant

    2003-11-01

    Highly specific interactions between DNA could potentially be amplified if the DNA interactions were utilized to assemble large scale parts. Fluidic assembly of microsystem parts has the potential for rapid and accurate placement of otherwise difficult to handle pieces. Ideally, each part would have a different chemical interaction that allowed it to interact with the substrate only in specific areas. One easy way to obtain a multiple chemical permutations is to use synthetic DNA oligomers. Si parts were prepared using silicon-on-insulator technology microfabrication techniques. Several surface chemistry protocols were developed to react commercial oligonucleotides to the parts. However, no obvious assembly was achieved. It was thought that small defects on the surface did not allow the microparts to be in close enough proximity for DNA hybridization, and this was. in part, confirmed by interferometry. To assist in the hybridization, plastic, pliable parts were manufactured and a new chemistry was developed. However, assembly was still absent even with the application of force. It is presently thought that one of three mechanisms is preventing the assembly. The surfaces of the two solid substrates can not get in close enough proximity, the surface chemistry lacks sufficient density to keep the parts from separating, or DNA interactions in close proximity on solid substrates are forbidden. These possibilities are discussed in detail.

  2. Electronic signal generators: A compilation

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Electronic signal generator data based on solid state concepts were simplified or refined to meet requirements, such as reliability, simplicity, fail-safe characteristics, and the capability of withstanding environmental extremes. Pulse generators, high voltage pulse generators, oscillators, analog signal generators, square wave signal generators, and special function signal generators are described.

  3. Differential assembly of GPCR signaling complexes determines signaling specificity.

    PubMed

    Maurice, Pascal; Benleulmi-Chaachoua, Abla; Jockers, Ralf

    2012-01-01

    Recent proteomic and biochemical evidence indicates that cellular -signaling is organized in protein modules. G protein-coupled receptors (GPCRs) are privileged entry points for extracellular signals that are transmitted through the plasma membrane into the cell. The adequate cellular response and signaling specificity is regulated by GPCR-associated protein modules. The composition of these modules is dynamic and might depend on receptor stimulation, the proteome of a given cellular context, the subcellular localization of receptor-associated modules, the formation of GPCR oligomers and the variation of expression levels of components of these modules under physiological, for example circadian rhythm, or pathological conditions. The current article will highlight the importance of GPCR-associated protein modules as a biochemical basis for signaling specificity.

  4. Ultrasensitive Responses and Specificity in Cell Signaling

    PubMed Central

    2010-01-01

    Background Interconnected cell signaling pathways are able to efficiently and accurately transmit a multitude of different signals, despite an inherent potential for undesirable levels of cross-talk. To ensure that an appropriate response is produced, biological systems have evolved network-level mechanisms that insulate pathways from crosstalk and prevent 'leaking' or 'spillover' between pathways. Many signaling pathways have been shown to respond in an ultrasensitive (switch-like) fashion to graded input, and this behavior may influence specificity. The relationship of ultrasensitivity to signaling specificity has not been extensively explored. Results We studied the behavior of simple mathematical models of signaling networks composed of two interconnected pathways that share an intermediate component, asking if the two pathways in the network could exhibit both output specificity (preferentially activate their own output) and input fidelity (preferentially respond to their own input). Previous results with weakly-activated pathways indicated that neither mutual specificity nor mutual fidelity were obtainable in the absence of an insulating mechanism, such as cross-pathway inhibition, combinatorial signaling or scaffolding/compartmentalization. Here we found that mutual specificity is obtainable for hyperbolic or ultrasensitive pathways, even in the absence of an insulating mechanism. However, mutual fidelity is impossible at steady-state, even if pathways are hyperbolic or ultrasensitive. Nevertheless, ultrasensitivity does provide advantages in attaining specificity and fidelity to networks that contain an insulating mechanism. For networks featuring cross-pathway inhibition or combinatorial signaling, ultrasensitive activation can increase specificity in a limited way, and can only be utilized by one of the two pathways. In contrast, for networks featuring scaffolding/compartmentalization, ultrasensitive activation of both pathways can dramatically improve

  5. Thiol chemistry and specificity in redox signaling.

    PubMed

    Winterbourn, Christine C; Hampton, Mark B

    2008-09-01

    Exposure of cells to sublethal oxidative stress results in the modulation of various signaling pathways. Oxidants can activate and inactivate transcription factors, membrane channels, and metabolic enzymes, and regulate calcium-dependent and phosphorylation signaling pathways. Oxidation and reduction of thiol proteins are thought to be the major mechanisms by which reactive oxidants integrate into cellular signal transduction pathways. This review focuses on mechanisms for sensing and transmitting redox signals, from the perspective of their chemical reactivity with specific oxidants. We discuss substrate preferences for different oxidants and how the kinetics of these reactions determines how each oxidant will react in a cell. This kinetic approach helps to identify initial oxidant-sensitive targets and elucidate mechanisms involved in transmission of redox signals. It indicates that only those proteins with very high reactivity, such as peroxiredoxins, are likely to be direct targets for hydrogen peroxide. Other more modestly reactive thiol proteins such as protein tyrosine phosphatases are more likely to become oxidized by an indirect mechanism. The review also examines oxidative changes observed during receptor-mediated signaling, the strengths and limitations of detection methods for reactive oxidant production, and the evidence for hydrogen peroxide acting as the second messenger. We discuss areas where observations in cell systems can be rationalized with the reactivity of specific oxidants and where further work is needed to understand the mechanisms involved.

  6. Species-specific beaked whale echolocation signals.

    PubMed

    Baumann-Pickering, Simone; McDonald, Mark A; Simonis, Anne E; Solsona Berga, Alba; Merkens, Karlina P B; Oleson, Erin M; Roch, Marie A; Wiggins, Sean M; Rankin, Shannon; Yack, Tina M; Hildebrand, John A

    2013-09-01

    Beaked whale echolocation signals are mostly frequency-modulated (FM) upsweep pulses and appear to be species specific. Evolutionary processes of niche separation may have driven differentiation of beaked whale signals used for spatial orientation and foraging. FM pulses of eight species of beaked whales were identified, as well as five distinct pulse types of unknown species, but presumed to be from beaked whales. Current evidence suggests these five distinct but unidentified FM pulse types are also species-specific and are each produced by a separate species. There may be a relationship between adult body length and center frequency with smaller whales producing higher frequency signals. This could be due to anatomical and physiological restraints or it could be an evolutionary adaption for detection of smaller prey for smaller whales with higher resolution using higher frequencies. The disadvantage of higher frequencies is a shorter detection range. Whales echolocating with the highest frequencies, or broadband, likely lower source level signals also use a higher repetition rate, which might compensate for the shorter detection range. Habitat modeling with acoustic detections should give further insights into how niches and prey may have shaped species-specific FM pulse types.

  7. Signal processing and electronic noise in LZ

    NASA Astrophysics Data System (ADS)

    Khaitan, D.

    2016-03-01

    The electronics of the LUX-ZEPLIN (LZ) experiment, the 10-tonne dark matter detector to be installed at the Sanford Underground Research Facility (SURF), consists of low-noise dual-gain amplifiers and a 100-MHz, 14-bit data acquisition system for the TPC PMTs. Pre-prototypes of the analog amplifiers and the 32-channel digitizers were tested extensively with simulated pulses that are similar to the prompt scintillation light and the electroluminescence signals expected in LZ. These studies are used to characterize the noise and to measure the linearity of the system. By increasing the amplitude of the test signals, the effect of saturating the amplifier and the digitizers was studied. The RMS ADC noise of the digitizer channels was measured to be 1.19± 0.01 ADCC. When a high-energy channel of the amplifier is connected to the digitizer, the measured noise remained virtually unchanged, while the noise added by a low-energy channel was estimated to be 0.38 ± 0.02 ADCC (46 ± 2 μV). A test facility is under construction to study saturation, mitigate noise and measure the performance of the LZ electronics and data acquisition chain.

  8. Electron environment specification models for Galileo

    NASA Astrophysics Data System (ADS)

    Lazaro, Didier; Bourdarie, Sebastien; Hands, Alex; Ryden, Keith; Nieminen, Petteri

    The MEO radiation hazard is becoming an increasingly important consideration with an ever rising number of satellites missions spending most of their time in this environment. This region lies in the heart of the highly dynamic electron radiation belt, where very large radiation doses can be encountered unless proper shielding to critical systems and components is applied. Significant internal charging hazards also arise in the MEO regime. For electron environment specification at Galileo altitude, new models have been developed and implemented: long term effects model for dose evaluation, statistical model for internal charging analysis and latitudinal model for ELDRS analysis. Models outputs, tools and validation with observations (Giove-A data) and existing models (such as FLUMIC) are presented . "Energetic Electron Environment Models for MEO" Co 21403/08/NL/JD in consortium with ONERA, QinetiQ, SSTL and CNES .

  9. Diverse FGF receptor signaling controls astrocyte specification and proliferation

    SciTech Connect

    Kang, Kyungjun; Song, Mi-Ryoung

    2010-05-07

    During CNS development, pluripotency neuronal progenitor cells give rise in succession to neurons and glia. Fibroblast growth factor-2 (FGF-2), a major signal that maintains neural progenitors in the undifferentiated state, is also thought to influence the transition from neurogenesis to gliogenesis. Here we present evidence that FGF receptors and underlying signaling pathways transmit the FGF-2 signals that regulate astrocyte specification aside from its mitogenic activity. Application of FGF-2 to cortical progenitors suppressed neurogenesis whereas treatment with an FGFR antagonist in vitro promoted neurogenesis. Introduction of chimeric FGFRs with mutated tyrosine residues into cortical progenitors and drug treatments to specifically block individual downstream signaling pathways revealed that the overall activity of FGFR rather than individual autophosphorylation sites is important for delivering signals for glial specification. In contrast, a signal for cell proliferation by FGFR was mainly delivered by MAPK pathway. Together our findings indicate that FGFR activity promotes astrocyte specification in the developing CNS.

  10. Biomimetic catalysts responsive to specific chemical signals

    SciTech Connect

    Zhao, Yan

    2015-03-04

    Part 1. Design of Biomimetic Catalysts Based on Amphiphilic Systems The overall objective of our research is to create biomimetic catalysts from amphiphilic molecules. More specifically, we aim to create supramolecular systems that can be used to control the microenvironment around a catalytic center in a biomimetic fashion and apply the learning to construct supramolecular catalysts with novel functions found in enzymatic catalysts. We have prepared synthetic molecules (i.e., foldamers) that could fold into helical structures with nanometer-sized internal hydrophilic cavities. Cavities of this size are typically observed only in the tertiary and quaternary structures of proteins but were formed in our foldamer prepared in just a few steps from the monomer. Similar to many proteins, our foldamers displayed cooperativity in the folding/unfolding equilibrium and followed a two-state conformational transition. In addition, their conformational change could be triggered by solvent polarity, pH, or presence of metal ions and certain organic molecules. We studied their environmentally dependent conformational changes in solutions, surfactant micelles, and lipid bilayer membranes. Unlike conventional rigid supramolecular host, a foldamer undergoes conformational change during guest binding. Our study in the molecular recognition of an oligocholate host yielded some extremely exciting results. Cooperativity between host conformation and host–guest interactions was found to “magnify” weak binding interactions. In other words, since binding affinity is determined by the overall change of free energy during the binding, guest-induced conformational change of the host, whether near or far from the binding site, affects the binding. This study has strong implications in catalysis because enzymes have been hypothesized to harvest similar intramolecular forces to strengthen their binding with the transition state of an enzyme-catalyzed reaction. The supramolecular and

  11. Integrated electronics for peripheral nerve recording and signal processing.

    PubMed

    Limnuson, Kanokwan; Tyler, Dustin J; Mohseni, Pedram

    2009-01-01

    This paper describes the integrated circuit implementation of an electronic system for peripheral nerve recording and signal processing. Specifically, the system aims to record and condition neural activity from the phrenic nerve as a good indicator for breathing, and generate a stimulus trigger signal for a laryngeal pacemaker device to reanimate a paralyzed muscle with electrical stimulation paced with respiration. The 2.2 x 2.2-mm(2) integrated circuit is fabricated using the AMI 1.5 microm 2P/2M n-well CMOS process, and consumes 1 mW from +/-1.5 V. System architecture, circuit design, simulation results, and measurement data in benchtop experiments are presented.

  12. A generalizable platform for interrogating target- and signal-specific consequences of electrophilic modifications in redox-dependent cell signaling.

    PubMed

    Lin, Hong-Yu; Haegele, Joseph A; Disare, Michael T; Lin, Qishan; Aye, Yimon

    2015-05-20

    Despite the known propensity of small-molecule electrophiles to react with numerous cysteine-active proteins, biological actions of individual signal inducers have emerged to be chemotype-specific. To pinpoint and quantify the impacts of modifying one target out of the whole proteome, we develop a target-protein-personalized "electrophile toolbox" with which specific intracellular targets can be selectively modified at a precise time by specific reactive signals. This general methodology, T-REX (targetable reactive electrophiles and oxidants), is established by (1) constructing a platform that can deliver a range of electronic and sterically different bioactive lipid-derived signaling electrophiles to specific proteins in cells; (2) probing the kinetics of targeted delivery concept, which revealed that targeting efficiency in cells is largely driven by initial on-rate of alkylation; and (3) evaluating the consequences of protein-target- and small-molecule-signal-specific modifications on the strength of downstream signaling. These data show that T-REX allows quantitative interrogations into the extent to which the Nrf2 transcription factor-dependent antioxidant response element (ARE) signaling is activated by selective electrophilic modifications on Keap1 protein, one of several redox-sensitive regulators of the Nrf2-ARE axis. The results document Keap1 as a promiscuous electrophile-responsive sensor able to respond with similar efficiencies to discrete electrophilic signals, promoting comparable strength of Nrf2-ARE induction. T-REX is also able to elicit cell activation in cases in which whole-cell electrophile flooding fails to stimulate ARE induction prior to causing cytotoxicity. The platform presents a previously unavailable opportunity to elucidate the functional consequences of small-molecule-signal- and protein-target-specific electrophilic modifications in an otherwise unaffected cellular background.

  13. A generalizable platform for interrogating target- and signal-specific consequences of electrophilic modifications in redox-dependent cell signaling.

    PubMed

    Lin, Hong-Yu; Haegele, Joseph A; Disare, Michael T; Lin, Qishan; Aye, Yimon

    2015-05-20

    Despite the known propensity of small-molecule electrophiles to react with numerous cysteine-active proteins, biological actions of individual signal inducers have emerged to be chemotype-specific. To pinpoint and quantify the impacts of modifying one target out of the whole proteome, we develop a target-protein-personalized "electrophile toolbox" with which specific intracellular targets can be selectively modified at a precise time by specific reactive signals. This general methodology, T-REX (targetable reactive electrophiles and oxidants), is established by (1) constructing a platform that can deliver a range of electronic and sterically different bioactive lipid-derived signaling electrophiles to specific proteins in cells; (2) probing the kinetics of targeted delivery concept, which revealed that targeting efficiency in cells is largely driven by initial on-rate of alkylation; and (3) evaluating the consequences of protein-target- and small-molecule-signal-specific modifications on the strength of downstream signaling. These data show that T-REX allows quantitative interrogations into the extent to which the Nrf2 transcription factor-dependent antioxidant response element (ARE) signaling is activated by selective electrophilic modifications on Keap1 protein, one of several redox-sensitive regulators of the Nrf2-ARE axis. The results document Keap1 as a promiscuous electrophile-responsive sensor able to respond with similar efficiencies to discrete electrophilic signals, promoting comparable strength of Nrf2-ARE induction. T-REX is also able to elicit cell activation in cases in which whole-cell electrophile flooding fails to stimulate ARE induction prior to causing cytotoxicity. The platform presents a previously unavailable opportunity to elucidate the functional consequences of small-molecule-signal- and protein-target-specific electrophilic modifications in an otherwise unaffected cellular background. PMID:25909755

  14. Location-specific cuticular hydrocarbon signals in a social insect.

    PubMed

    Wang, Qike; Goodger, Jason Q D; Woodrow, Ian E; Elgar, Mark A

    2016-03-30

    Social insects use cuticular hydrocarbons (CHCs) to convey different social signals, including colony or nest identity. Despite extensive investigations, the exact source and identity of CHCs that act as nest-specific identification signals remain largely unknown. Perhaps this is because studies that identify CHC signals typically use organic solvents to extract a single sample from the entire animal, thereby analysing a cocktail of chemicals that may serve several signal functions. We took a novel approach by first identifying CHC profiles from different body parts of ants (Iridomyrmex purpureus), then used behavioural bioassays to reveal the location of specific social signals. The CHC profiles of both workers and alates varied between different body parts, and workers paid more attention to the antennae of non-nest-mate and the legs of nest-mate workers. Workers responded less aggressively to non-nest-mate workers if the CHCs on the antennae of their opponents were removed with a solvent. These data indicate that CHCs located on the antennae reveal nest-mate identity and, remarkably, that antennae both convey and receive social signals. Our approach and findings could be valuably applied to chemical signalling in other behavioural contexts, and provide insights that were otherwise obscured by including chemicals that either have no signal function or may be used in other contexts.

  15. Specificity, cross-talk and adaptation in Interferon signaling

    NASA Astrophysics Data System (ADS)

    Zilman, Anton

    Innate immune system is the first line of defense of higher organisms against pathogens. It coordinates the behavior of millions of cells of multiple types, achieved through numerous signaling molecules. This talk focuses on the signaling specificity of a major class of signaling molecules - Type I Interferons - which are also used therapeutically in the treatment of a number of diseases, such as Hepatitis C, multiple sclerosis and some cancers. Puzzlingly, different Interferons act through the same cell surface receptor but have different effects on the target cells. They also exhibit a strange pattern of temporal cross-talk resulting in a serious clinical problem - loss of response to Interferon therapy. We combined mathematical modeling with quantitative experiments to develop a quantitative model of specificity and adaptation in the Interferon signaling pathway. The model resolves several outstanding experimental puzzles and directly affects the clinical use of Type I Interferons in treatment of viral hepatitis and other diseases.

  16. Electronic filters, signal conversion apparatus, hearing aids and methods

    NASA Technical Reports Server (NTRS)

    Morley, Jr., Robert E. (Inventor); Engebretson, A. Maynard (Inventor); Engel, George L. (Inventor); Sullivan, Thomas J. (Inventor)

    1994-01-01

    An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits associated with the filter stages for storing electrical representations of filter parameters. The filter stages include circuits for respectively adding the electrical representations of the filter parameters to the electrical signal to be filtered thereby producing a set of filter sum signals. At least one of the filter stages includes circuitry for producing a filter signal in substantially logarithmic form at its output by combining a filter sum signal for that filter stage with a signal from an output of another filter stage. The signal processing circuitry produces an intermediate output signal, and a multiplexer connected to the signal processing circuit multiplexes the intermediate output signal with the electrical signal to be filtered so that the logarithmic filter operates as both a logarithmic prefilter and a logarithmic postfilter. Other electronic filters, signal conversion apparatus, electroacoustic systems, hearing aids and methods are also disclosed.

  17. The control of specificity in guard cell signal transduction

    PubMed Central

    Hetherington, A. M.

    1998-01-01

    Stomatal guard cells have proven to be an attractive system for dissecting the mechanisms of stimulus-response coupling in plants. In this review we focus on the intracellular signal transduction pathways by which extracellular signals bring about closure and opening of the stomatal pore. It is proposed that guard cell signal transduction pathways may be organized into functional arrays or signalling cassettes that contain elements common to a number of converging signalling pathways. The purpose of these signalling cassettes may be to funnel extracellular signals down onto the ion transporters that control the fluxes of ions that underlie stomatal movements. Evidence is emerging that specificity in guard cell signalling may be, in part, encoded in complex spatio-temporal patterns of increases in the concentration of cytosolic-free calcium ([Ca2+]cyt). It is suggested that oscillations in [Ca2+]cyt may generate calcium signatures that encode information concerning the stimulus type and strength. New evidence is presented that suggests that these calcium signatures may integrate information when many stimuli are present.

  18. Calcium specificity signaling mechanisms in abscisic acid signal transduction in Arabidopsis guard cells

    PubMed Central

    Brandt, Benjamin; Munemasa, Shintaro; Wang, Cun; Nguyen, Desiree; Yong, Taiming; Yang, Paul G; Poretsky, Elly; Belknap, Thomas F; Waadt, Rainer; Alemán, Fernando; Schroeder, Julian I

    2015-01-01

    A central question is how specificity in cellular responses to the eukaryotic second messenger Ca2+ is achieved. Plant guard cells, that form stomatal pores for gas exchange, provide a powerful system for in depth investigation of Ca2+-signaling specificity in plants. In intact guard cells, abscisic acid (ABA) enhances (primes) the Ca2+-sensitivity of downstream signaling events that result in activation of S-type anion channels during stomatal closure, providing a specificity mechanism in Ca2+-signaling. However, the underlying genetic and biochemical mechanisms remain unknown. Here we show impairment of ABA signal transduction in stomata of calcium-dependent protein kinase quadruple mutant plants. Interestingly, protein phosphatase 2Cs prevent non-specific Ca2+-signaling. Moreover, we demonstrate an unexpected interdependence of the Ca2+-dependent and Ca2+-independent ABA-signaling branches and the in planta requirement of simultaneous phosphorylation at two key phosphorylation sites in SLAC1. We identify novel mechanisms ensuring specificity and robustness within stomatal Ca2+-signaling on a cellular, genetic, and biochemical level. DOI: http://dx.doi.org/10.7554/eLife.03599.001 PMID:26192964

  19. Calcium specificity signaling mechanisms in abscisic acid signal transduction in Arabidopsis guard cells.

    PubMed

    Brandt, Benjamin; Munemasa, Shintaro; Wang, Cun; Nguyen, Desiree; Yong, Taiming; Yang, Paul G; Poretsky, Elly; Belknap, Thomas F; Waadt, Rainer; Alemán, Fernando; Schroeder, Julian I

    2015-07-20

    A central question is how specificity in cellular responses to the eukaryotic second messenger Ca(2+) is achieved. Plant guard cells, that form stomatal pores for gas exchange, provide a powerful system for in depth investigation of Ca(2+)-signaling specificity in plants. In intact guard cells, abscisic acid (ABA) enhances (primes) the Ca(2+)-sensitivity of downstream signaling events that result in activation of S-type anion channels during stomatal closure, providing a specificity mechanism in Ca(2+)-signaling. However, the underlying genetic and biochemical mechanisms remain unknown. Here we show impairment of ABA signal transduction in stomata of calcium-dependent protein kinase quadruple mutant plants. Interestingly, protein phosphatase 2Cs prevent non-specific Ca(2+)-signaling. Moreover, we demonstrate an unexpected interdependence of the Ca(2+)-dependent and Ca(2+)-independent ABA-signaling branches and the in planta requirement of simultaneous phosphorylation at two key phosphorylation sites in SLAC1. We identify novel mechanisms ensuring specificity and robustness within stomatal Ca(2+)-signaling on a cellular, genetic, and biochemical level.

  20. Electronic modulation of biochemical signal generation

    NASA Astrophysics Data System (ADS)

    Gordonov, Tanya; Kim, Eunkyoung; Cheng, Yi; Ben-Yoav, Hadar; Ghodssi, Reza; Rubloff, Gary; Yin, Jun-Jie; Payne, Gregory F.; Bentley, William E.

    2014-08-01

    Microelectronic devices that contain biological components are typically used to interrogate biology rather than control biological function. Patterned assemblies of proteins and cells have, however, been used for in vitro metabolic engineering, where coordinated biochemical pathways allow cell metabolism to be characterized and potentially controlled on a chip. Such devices form part of technologies that attempt to recreate animal and human physiological functions on a chip and could be used to revolutionize drug development. These ambitious goals will, however, require new biofabrication methodologies that help connect microelectronics and biological systems and yield new approaches to device assembly and communication. Here, we report the electrically mediated assembly, interrogation and control of a multi-domain fusion protein that produces a bacterial signalling molecule. The biological system can be electrically tuned using a natural redox molecule, and its biochemical response is shown to provide the signalling cues to drive bacterial population behaviour. We show that the biochemical output of the system correlates with the electrical input charge, which suggests that electrical inputs could be used to control complex on-chip biological processes.

  1. Electronic modulation of biochemical signal generation.

    PubMed

    Gordonov, Tanya; Kim, Eunkyoung; Cheng, Yi; Ben-Yoav, Hadar; Ghodssi, Reza; Rubloff, Gary; Yin, Jun-Jie; Payne, Gregory F; Bentley, William E

    2014-08-01

    Microelectronic devices that contain biological components are typically used to interrogate biology rather than control biological function. Patterned assemblies of proteins and cells have, however, been used for in vitro metabolic engineering, where coordinated biochemical pathways allow cell metabolism to be characterized and potentially controlled on a chip. Such devices form part of technologies that attempt to recreate animal and human physiological functions on a chip and could be used to revolutionize drug development. These ambitious goals will, however, require new biofabrication methodologies that help connect microelectronics and biological systems and yield new approaches to device assembly and communication. Here, we report the electrically mediated assembly, interrogation and control of a multi-domain fusion protein that produces a bacterial signalling molecule. The biological system can be electrically tuned using a natural redox molecule, and its biochemical response is shown to provide the signalling cues to drive bacterial population behaviour. We show that the biochemical output of the system correlates with the electrical input charge, which suggests that electrical inputs could be used to control complex on-chip biological processes.

  2. Signalling pathways that control vertebrate haematopoietic stem cell specification

    PubMed Central

    Clements, Wilson K.; Traver, David

    2014-01-01

    Haematopoietic stem cells (HSCs) are tissue-specific stem cells that replenish all mature blood lineages during the lifetime of an individual. Clinically, HSCs form the foundation of transplantation-based therapies for leukaemias and congenital blood disorders. Researchers have long been interested in understanding the normal signalling mechanisms that specify HSCs in the embryo, in part because recapitulating these requirements in vitro might provide a means to generate immune-compatible HSCs for transplantation. Recent embryological work has demonstrated the existence of previously unknown signalling requirements. Moreover, it is now clear that gene expression in the nearby somite is integrally involved in regulating the transition of the embryonic endothelium to a haemogenic fate. Here, we review current knowledge of the intraembryonic signals required for the specification of HSCs in vertebrates. PMID:23618830

  3. Collection and analysis of specific ELINT Signal Parameters

    NASA Technical Reports Server (NTRS)

    Wilson, Lonnie A.

    1985-01-01

    This report was a followup to, Collection and Analysis of Specific ELINT Signal Parameters, DTIC A166507, 23 June 1985. The programs and hardware assembled for the above mentioned report were used to analyze two types of radar, the PPS-6 and the HOOD radars. The typical ELINT parameters of frequency, pulse width, and pulse repetition rate were collected and analyzed.

  4. Arbuscular Mycorrhiza–Specific Signaling in Rice Transcends the Common Symbiosis Signaling Pathway[W

    PubMed Central

    Gutjahr, Caroline; Banba, Mari; Croset, Vincent; An, Kyungsook; Miyao, Akio; An, Gynheung; Hirochika, Hirohiko; Imaizumi-Anraku, Haruko; Paszkowski, Uta

    2008-01-01

    Knowledge about signaling in arbuscular mycorrhizal (AM) symbioses is currently restricted to the common symbiosis (SYM) signaling pathway discovered in legumes. This pathway includes calcium as a second messenger and regulates both AM and rhizobial symbioses. Both monocotyledons and dicotyledons form symbiotic associations with AM fungi, and although they differ markedly in the organization of their root systems, the morphology of colonization is similar. To identify and dissect AM-specific signaling in rice (Oryza sativa), we developed molecular phenotyping tools based on gene expression patterns that monitor various steps of AM colonization. These tools were used to distinguish common SYM-dependent and -independent signaling by examining rice mutants of selected putative legume signaling orthologs predicted to be perturbed both upstream (CASTOR and POLLUX) and downstream (CCAMK and CYCLOPS) of the central, calcium-spiking signal. All four mutants displayed impaired AM interactions and altered AM-specific gene expression patterns, therefore demonstrating functional conservation of SYM signaling between distant plant species. In addition, differential gene expression patterns in the mutants provided evidence for AM-specific but SYM-independent signaling in rice and furthermore for unexpected deviations from the SYM pathway downstream of calcium spiking. PMID:19033527

  5. Specific features of vowel-like signals of white whales

    NASA Astrophysics Data System (ADS)

    Bel'Kovich, V. M.; Kreichi, S. A.

    2004-05-01

    The set of acoustic signals of White-Sea white whales comprises about 70 types of signals. Six of them occur most often and constitute 75% of the total number of signals produced by these animals. According to behavioral reactions, white whales distinguish each other by acoustic signals, which is also typical of other animal species and humans. To investigate this phenomenon, signals perceived as vowel-like sounds of speech, including sounds perceived as a “bleat,” were chosen A sample of 480 signals recorded in June and July, 2000, in the White Sea within a reproductive assemblage of white whales near the Large Solovetskii Island was studied. Signals were recorded on a digital data carrier (a SONY minidisk) in the frequency range of 0.06 20 kHz. The purpose of the study was to reveal the perceptive and acoustic features specific to individual animals. The study was carried out using the methods of structural analysis of vocal speech that are employed in lingual criminalistics to identify a speaking person. It was demonstrated that this approach allows one to group the signals by coincident perceptive and acoustic parameters with assigning individual attributes to single parameters. This provided an opportunity to separate conditionally about 40 different sources of acoustic signals according to the totality of coincidences, which corresponded to the number of white whales observed visually. Thus, the application of this method proves to be very promising for the acoustic identification of white whales and other marine mammals, this possibility being very important for biology.

  6. Ionospheric electron density profile estimation using commercial AM broadcast signals

    NASA Astrophysics Data System (ADS)

    Yu, De; Ma, Hong; Cheng, Li; Li, Yang; Zhang, Yufeng; Chen, Wenjun

    2015-08-01

    A new method for estimating the bottom electron density profile by using commercial AM broadcast signals as non-cooperative signals is presented in this paper. Without requiring any dedicated transmitters, the required input data are the measured elevation angles of signals transmitted from the known locations of broadcast stations. The input data are inverted for the QPS model parameters depicting the electron density profile of the signal's reflection area by using a probabilistic inversion technique. This method has been validated on synthesized data and used with the real data provided by an HF direction-finding system situated near the city of Wuhan. The estimated parameters obtained by the proposed method have been compared with vertical ionosonde data and have been used to locate the Shijiazhuang broadcast station. The simulation and experimental results indicate that the proposed ionospheric sounding method is feasible for obtaining useful electron density profiles.

  7. Neuromorphic opto-electronic integrated circuits for optical signal processing

    NASA Astrophysics Data System (ADS)

    Romeira, B.; Javaloyes, J.; Balle, S.; Piro, O.; Avó, R.; Figueiredo, J. M. L.

    2014-08-01

    The ability to produce narrow optical pulses has been extensively investigated in laser systems with promising applications in photonics such as clock recovery, pulse reshaping, and recently in photonics artificial neural networks using spiking signal processing. Here, we investigate a neuromorphic opto-electronic integrated circuit (NOEIC) comprising a semiconductor laser driven by a resonant tunneling diode (RTD) photo-detector operating at telecommunication (1550 nm) wavelengths capable of excitable spiking signal generation in response to optical and electrical control signals. The RTD-NOEIC mimics biologically inspired neuronal phenomena and possesses high-speed response and potential for monolithic integration for optical signal processing applications.

  8. 29 CFR 1926.1420 - Signals-radio, telephone or other electronic transmission of signals.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Signals-radio, telephone or other electronic transmission of signals. 1926.1420 Section 1926.1420 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL... CONSTRUCTION Cranes and Derricks in Construction § 1926.1420 Signals—radio, telephone or other...

  9. 29 CFR 1926.1420 - Signals-radio, telephone or other electronic transmission of signals.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Signals-radio, telephone or other electronic transmission of signals. 1926.1420 Section 1926.1420 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL... CONSTRUCTION Cranes and Derricks in Construction § 1926.1420 Signals—radio, telephone or other...

  10. 29 CFR 1926.1420 - Signals-radio, telephone or other electronic transmission of signals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Signals-radio, telephone or other electronic transmission of signals. 1926.1420 Section 1926.1420 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL... CONSTRUCTION Cranes and Derricks in Construction § 1926.1420 Signals—radio, telephone or other...

  11. 29 CFR 1926.1420 - Signals-radio, telephone or other electronic transmission of signals.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Signals-radio, telephone or other electronic transmission of signals. 1926.1420 Section 1926.1420 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL... CONSTRUCTION Cranes and Derricks in Construction § 1926.1420 Signals—radio, telephone or other...

  12. Role of phosphorylation in progesterone receptor signaling and specificity.

    PubMed

    Hagan, Christy R; Daniel, Andrea R; Dressing, Gwen E; Lange, Carol A

    2012-06-24

    Progesterone receptors (PR), in concert with peptide growth factor-initiated signaling pathways, initiate massive expansion of the epithelial cell compartment associated with the process of alveologenesis in the developing mammary gland. PR-dependent signaling events also contribute to inappropriate proliferation observed in breast cancer. Notably, PR-B isoform-specific cross talk with growth factor-driven pathways is required for the proliferative actions of progesterone. Indeed, PRs act as heavily phosphorylated transcription factor "sensors" for mitogenic protein kinases that are often elevated and/or constitutively activated in invasive breast cancers. In addition, phospho-PR-target genes frequently include the components of mitogenic signaling pathways, revealing a mechanism for feed-forward signaling that confers increased responsiveness of, PR +mammary epithelial cells to these same mitogenic stimuli. Understanding the mechanisms and isoform selectivity of PR/kinase interactions may yield further insight into targeting altered signaling networks in breast and other hormonally responsive cancers (i.e. lung, uterine and ovarian) in the clinic. This review focuses on PR phosphorylation by mitogenic protein kinases and mechanisms of PR-target gene selection that lead to increased cell proliferation.

  13. Electronic filters, signal conversion apparatus, hearing aids and methods

    NASA Technical Reports Server (NTRS)

    Morley, Jr., Robert E. (Inventor); Engebretson, A. Maynard (Inventor); Engel, George L. (Inventor); Sullivan, Thomas J. (Inventor)

    1992-01-01

    An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits as GOVERNMENT SUPPORT This invention was made with U.S. Government support under Veterans Administration Contract VA KV 674P857 and National Aeronautics and Space Administration (NASA) Research Grant No. NAG10-0040. The U.S. Government has certain rights in this invention.

  14. Inelastic vibrational signals in electron transport across graphene nanoconstrictions

    NASA Astrophysics Data System (ADS)

    Gunst, Tue; Markussen, Troels; Stokbro, Kurt; Brandbyge, Mads

    2016-06-01

    We present calculations of the inelastic vibrational signals in the electrical current through a graphene nanoconstriction. We find that the inelastic signals are only present when the Fermi-level position is tuned to electron transmission resonances, thus, providing a fingerprint which can link an electron transmission resonance to originate from the nanoconstriction. The calculations are based on a novel first-principles method which includes the phonon broadening due to coupling with phonons in the electrodes. We find that the signals are modified due to the strong coupling to the electrodes, however, still remain as robust fingerprints of the vibrations in the nanoconstriction. We investigate the effect of including the full self-consistent potential drop due to finite bias and gate doping on the calculations and find this to be of minor importance.

  15. Benzodiazepines: electron affinity, receptors and cell signaling - a multifaceted approach.

    PubMed

    Kovacic, Peter; Ott, Nadia; Cooksy, Andrew L

    2013-12-01

    This report entails a multifaceted approach to benzodiazepine (BZ) action, involving electron affinity, receptors, cell signaling and other aspects. Computations of the electron affinities (EAs) of different BZs have been carried out to establish the effect of various substituents on their EA. These computations were undertaken to serve as a first step in determining what role electron transfer (ET) plays in BZ activity. The calculations were conducted on the premise that the nature of the substituent will either decrease or increase the electron density of the benzene ring, thus altering the ability of the molecule to accept an electron. Investigations were performed on the effect of drug protonation on EA. Similarities involving substituent effects in prior electrochemical studies are also discussed. As part of the multifaceted approach, EA is linked to ET, which appears to play a role in therapeutic activity and toxicity. There is extensive literature dealing with the role of receptors in BZ activity. Significant information on receptor involvement was reported more than 40 years ago. Gamma-aminobutyric acid (GABA) is known to be importantly involved. GABA is a probable mediator of BZ effects. BZ and GABA receptors, although not identical, are physiologically linked. Cell signaling is known to play a part in the biochemistry of BZ action. Various factors participated, such as gene expression, allosteric influence, toxic effects and therapeutic action. Evidence points to involvement of EA and ET in the mode of action in cell signaling. Oxidative stress and antioxidant effects are also addressed.

  16. Chaperone-mediated specificity in Ras and Rap signaling.

    PubMed

    Azoulay-Alfaguter, Inbar; Strazza, Marianne; Mor, Adam

    2015-01-01

    Ras and Rap proteins are closely related small guanosine triphosphatase (GTPases) that share similar effector-binding domains but operate in a very different signaling networks; Ras has a dominant role in cell proliferation, while Rap mediates cell adhesion. Ras and Rap proteins are regulated by several shared processes such as post-translational modification, phosphorylation, activation by guanine exchange factors and inhibition by GTPase-activating proteins. Sub-cellular localization and trafficking of these proteins to and from the plasma membrane are additional important regulatory features that impact small GTPases function. Despite its importance, the trafficking mechanisms of Ras and Rap proteins are not completely understood. Chaperone proteins play a critical role in trafficking of GTPases and will be the focus of the discussion in this work. We will review several aspects of chaperone biology focusing on specificity toward particular members of the small GTPase family. Understanding this specificity should provide key insights into drug development targeting individual small GTPases.

  17. Gallium arsenide enhances digital signal processing in electronic warfare

    NASA Astrophysics Data System (ADS)

    Hoffman, B.; Apte, D.

    1985-07-01

    The higher electron mobility and velocity of GaAs digital signal processing IC devices for electronic warfare (EW) allow operation times that are several times faster than those of ICs based on silicon. Particular benefits are foreseen for the response time and broadband capability of ECM systems. Many data manipulation methods can be implemented in emitter-coupled logic (ECL) GaAs devices, and digital GaAs RF memories are noted to show great promise for improved ECM system performance while encompassing microwave frequency and chirp signal synthesis, repeater jamming, and multiple false target generation. EW digital frequency synthesizers are especially in need of GaAS IC technology, since bandwidth and resolution have been limited by ECL technology to about 250 MHz.

  18. Signal conditioning electronics for a laser vector velocimeter.

    NASA Technical Reports Server (NTRS)

    Crosswy, F. L.; Hornkohl, J. O.

    1973-01-01

    A type of laser velocimeter termed a laser vector velocimeter (LVV) resolves the 180 deg directional ambiguity problem of the conventional laser velocimeter by exploiting optical frequency translation techniques and frequency division demultiplexing techniques. This paper defines some fundamental LVV system signal characteristics and signal conditioning and data acquisition problems. The signal conditioning electronics for a three velocity component LVV system are described. Data obtained from atmospheric wind velocity measurements using a two velocity component LVV system are presented to illustrate the vector velocity measurement capabilities of the system. The operational status LVV systems presently in use are two orthogonal velocity component units. However, a laboratory status LVV system has been used to make three-dimensional vector velocity measurements.

  19. Optogenetic Control of Nodal Signaling Reveals a Temporal Pattern of Nodal Signaling Regulating Cell Fate Specification during Gastrulation.

    PubMed

    Sako, Keisuke; Pradhan, Saurabh J; Barone, Vanessa; Inglés-Prieto, Álvaro; Müller, Patrick; Ruprecht, Verena; Čapek, Daniel; Galande, Sanjeev; Janovjak, Harald; Heisenberg, Carl-Philipp

    2016-07-19

    During metazoan development, the temporal pattern of morphogen signaling is critical for organizing cell fates in space and time. Yet, tools for temporally controlling morphogen signaling within the embryo are still scarce. Here, we developed a photoactivatable Nodal receptor to determine how the temporal pattern of Nodal signaling affects cell fate specification during zebrafish gastrulation. By using this receptor to manipulate the duration of Nodal signaling in vivo by light, we show that extended Nodal signaling within the organizer promotes prechordal plate specification and suppresses endoderm differentiation. Endoderm differentiation is suppressed by extended Nodal signaling inducing expression of the transcriptional repressor goosecoid (gsc) in prechordal plate progenitors, which in turn restrains Nodal signaling from upregulating the endoderm differentiation gene sox17 within these cells. Thus, optogenetic manipulation of Nodal signaling identifies a critical role of Nodal signaling duration for organizer cell fate specification during gastrulation. PMID:27396324

  20. Hybrid optical/electronic signal processor for laser radar signals in fire control systems

    NASA Astrophysics Data System (ADS)

    Findley, George B., Jr.; Anderson, Christopher S.; Townley, S. K.; Pascale, Michael J.; Watson, Lee V.; Jenkinson, Howard A.

    1992-07-01

    This paper reports on the development of a hybrid optical/electronic signal processor for laser radar signals in fire control applications. The breadboard system being developed consists of three subsystems: (1) a signal generator producing target-representative signals, (2) the signal processor consisting of a radiometric channel and a Doppler channel, and (3) a data acquisition, analysis, and display subsystem. The radiometric channel provides target ladar cross section (LCS) resolved in crossrange, while the Doppler channel provides target radial velocity, also resolved in crossrange. Data from the two channels is fused and processed within the data analysis subsystem. Results are to be displayed in near real-time. The breadboard system will be used to demonstrate the capabilities of hybrid signal processor technology and to investigate processing laser radar returns for noncooperative target recognition, target orientation determination, and target trajectory estimation functions. It is anticipated that these functions will enhance the effectiveness of advanced fire control systems in future helicopters and ground vehicles.

  1. Spurious signals generated by electron tunneling on large reflector antennas

    NASA Technical Reports Server (NTRS)

    Higa, W. H.

    1975-01-01

    Large reflector antennas are currently fabricated by assembling a large number of small light aluminum panels onto a superstructure. A large number of aluminum-to-aluminum joints are inherently exposed to RF radiation on such an antenna. It is shown in this paper that the natural oxide layer on aluminum is of the correct thickness to permit electron tunneling through the Al-Al2O3-Al junctions. The nonlinearity due to the junctions then generates spurious signals when these antennas are used for simultaneous transmission and reception of signals at different frequencies. Moreover, the large number of junctions (rivets) on an antenna can combine to produce serious interference in these diplexed systems.

  2. Modification of Electron Cyclotron Maser Operation by Application of AN External Signal.

    NASA Astrophysics Data System (ADS)

    McCurdy, Alan Hugh

    The operation of the electron cyclotron resonance maser (ECRM) when subjected to an external rf signal is studied. The signal is introduced both by direct injection through a coupling hole in the oscillator and by modulating the electron beam in separate cavities, upstream of the oscillator. The gyrotron, a specific embodiment of the ECRM, can be phase locked by premodulating the electron beam. The required drive power levels are more than 15 dB below that predicted by Adler's widely applicable theory for single-cavity oscillators. The phase locking results are compared with a multi-cavity theory in which the free -running gyrotron is perturbed by a small current modulation. The same experimental method allows gyrotron priming, (pulse to pulse phase coherence), at drive-to-oscillator powers 50 dB below that required by magnetrons for equivalent phase control. A lumped circuit theory is used to predict the phase control introduced by the priming signal. The theory agrees with experiment at external signal frequencies within about 5 MHz of the gyrotron frequency. Significant reduction of frequency and amplitude noise is observed within the phase locking band. Reduction of pulse-to-pulse starting time jitter by almost an order of magnitude also occurs. Mechanisms of convective noise growth are investigated by using a technique of noise determination based on the oscillator response to an external signal. The general amplitude-frequency response of the ECRM to an applied external signal is also investigated. Three distinct regions of qualitatively different behavior are noted: soft excitation, hard excitation, and amplification. Control of axial modes in a gyrotron by injection of an external signal is shown for the first time. Finally, it has been verified experimentally, for the first time, that the ECRM is dominated by interaction of the right-hand circularly polarized electromagnetic wave with the electron beam.

  3. Low background signal readout electronics for the MAJORANA DEMONSTRATOR

    SciTech Connect

    Guinn, I.; Buuck, M.; Cuesta, C.; Detwiler, J. A.; Gruszko, J.; Leon, J.; Robertson, R. G. H.; Abgrall, N.; Bradley, A. W.; Chan, Y-D.; Mertens, S.; Poon, A. W. P.; Arnquist, I. J.; Hoppe, E. W.; Kouzes, R. T.; LaFerriere, B. D.; Orrell, J. L.; Avignone, F. T.; Baldenegro-Barrera, C. X.; Bertrand, F. E.; and others

    2015-08-17

    The MAJORANA Collaboration will seek neutrinoless double beta decay (0νββ) in {sup 76}Ge using isotopically enriched p-type point contact (PPC) high purity Germanium (HPGe) detectors. A tonne-scale array of HPGe detectors would require background levels below 1 count/ROI-tonne-year in the 4 keV region of interest (ROI) around the 2039 keV Q-value of the decay. In order to demonstrate the feasibility of such an experiment, the MAJORANA DEMONSTRATOR, a 40 kg HPGe detector array, is being constructed with a background goal of < 3 count/ROI-tonne-year, which is expected to scale down to < 1 count/ROI-tonne-year for a tonne-scale experiment. The signal readout electronics, which must be placed in close proximity to the detectors, present a challenge toward reaching this background goal. This talk will discuss the materials and design used to construct signal readout electronics with low enough backgrounds for the MAJORANA DEMONSTRATOR.

  4. Low Background Signal Readout Electronics for the Majorana Demonstrator

    SciTech Connect

    Guinn, Ian; Rielage, Keith Robert; Elliott, Steven Ray; Xu, Wenqin; Goett, John Jerome III

    2015-06-11

    The MAJORANA Collaboration will seek neutrinoless double beta decay (0νββ) in 76Ge using isotopically enriched p-type point contact (PPC) high purity Germanium (HPGe) detectors. A tonne-scale array of HPGe detectors would require background levels below 1 count/ROI-tonne-year in the 4 keV region of interest (ROI) around the 2039 keV Q-value of the decay. In order to demonstrate the feasibility of such an experiment, the MAJORANA DEMONSTRATOR, a 40 kg HPGe detector array, is being constructed. The DEMONSTRATOR has a background goal of < 3 counts/ROI-tonne-year, which is expected to scale down to < 1 count/ROI-tonne-year for a one tonne experiment. The signal readout electronics, which must be placed in close proximity to the detectors, present a challenge toward reaching this background goal. This paper discusses the materials and design used to construct signal readout electronics with low enough backgrounds for the MAJORANA DEMONSTRATOR.

  5. GSFC specification electronic data processing magnetic recording tape

    NASA Technical Reports Server (NTRS)

    Tinari, D. F.; Perry, J. L.

    1980-01-01

    The design requirements are given for magnetic oxide coated, electronic data processing tape, wound on reels. Magnetic recording tape types covered by this specification are intended for use on digital tape transports using the Non-Return-to-Zero-change-on-ones (NRZI) recording method for recording densities up to and including 800 characters per inch (cpi) and the Phase-Encoding (PE) recording method for a recording density of 1600 cpi.

  6. Modification of electron cyclotron maser operation by application of an external signal

    NASA Astrophysics Data System (ADS)

    McCurdy, Alan H.; Armstrong, C. M.; Bollen, W. M.

    1987-03-01

    Operation of the electron cyclotron resonance maser (ECRM) when subjected to an external rf signal is studied. The signal is introduced both by direct injection through a coupling hole in the oscillator and by modulating the electron beam in separate cavities, upstream of the oscillator. Experiments using both one and two pre bunching cavities are reported. It is found that the gyromonotron, a specific embodiment of the ECRM, can be phase locked by premodulating the electron beam. In this case, the required drive power levels are more than 15 dB below that predicated by Adler's widely applicable theory for single-cavity oscillators. In addition, the same method allows oscillator phase-locked systems, significant reduction of frequency and amplitude noise is observed within the locking band. In signal of a power level 65 dB below that of the oscillator. The general amplitude and frequency response of the ECRM to an applied external signal is also investigated. Three distinct regions of qualitatively different behavior are noted: soft excitation, which is free, self excited oscillation; hard excitation, where the oscillation requires an external impulse for start up; and amplifier, in which the output power level and frequency are linearly related to the drive in the small regime.

  7. Kinetic insulation as an effective mechanism for achieving pathway specificity in intracellular signaling networks

    PubMed Central

    Behar, Marcelo; Dohlman, Henrik G.; Elston, Timothy C.

    2007-01-01

    Intracellular signaling pathways that share common components often elicit distinct physiological responses. In most cases, the biochemical mechanisms responsible for this signal specificity remain poorly understood. Protein scaffolds and cross-inhibition have been proposed as strategies to prevent unwanted cross-talk. Here, we report a mechanism for signal specificity termed “kinetic insulation.” In this approach signals are selectively transmitted through the appropriate pathway based on their temporal profile. In particular, we demonstrate how pathway architectures downstream of a common component can be designed to efficiently separate transient signals from signals that increase slowly over time. Furthermore, we demonstrate that upstream signaling proteins can generate the appropriate input to the common pathway component regardless of the temporal profile of the external stimulus. Our results suggest that multilevel signaling cascades may have evolved to modulate the temporal profile of pathway activity so that stimulus information can be efficiently encoded and transmitted while ensuring signal specificity. PMID:17913886

  8. Ubiquity and specificity of reinforcement signals throughout the human brain.

    PubMed

    Vickery, Timothy J; Chun, Marvin M; Lee, Daeyeol

    2011-10-01

    Reinforcements and punishments facilitate adaptive behavior in diverse domains ranging from perception to social interactions. A conventional approach to understanding the corresponding neural substrates focuses on the basal ganglia and its dopaminergic projections. Here, we show that reinforcement and punishment signals are surprisingly ubiquitous in the gray matter of nearly every subdivision of the human brain. Humans played either matching-pennies or rock-paper-scissors games against computerized opponents while being scanned using fMRI. Multivoxel pattern analysis was used to decode previous choices and their outcomes, and to predict upcoming choices. Whereas choices were decodable from a confined set of brain structures, their outcomes were decodable from nearly all cortical and subcortical structures. In addition, signals related to both reinforcements and punishments were recovered reliably in many areas and displayed patterns not consistent with salience-based explanations. Thus, reinforcement and punishment might play global modulatory roles in the entire brain.

  9. High Energy Electron Signals from Dark Matter Annihilation in the Sun

    SciTech Connect

    Schuster, Philip; Toro, Natalia; Weiner, Neal; Yavin, Itay; /New York U., CCPP

    2012-04-09

    In this paper we discuss two mechanisms by which high energy electrons resulting from dark matter annihilations in or near the Sun can arrive at the Earth. Specifically, electrons can escape the sun if DM annihilates into long-lived states, or if dark matter scatters inelastically, which would leave a halo of dark matter outside of the sun. Such a localized source of electrons may affect the spectra observed by experiments with narrower fields of view oriented towards the sun, such as ATIC, differently from those with larger fields of view such as Fermi. We suggest a simple test of these possibilities with existing Fermi data that is more sensitive than limits from final state radiation. If observed, such a signal will constitute an unequivocal signature of dark matter.

  10. Coherence specific signal detection via chiral pump-probe spectroscopy.

    PubMed

    Holdaway, David I H; Collini, Elisabetta; Olaya-Castro, Alexandra

    2016-05-21

    We examine transient circular dichroism (TRCD) spectroscopy as a technique to investigate signatures of exciton coherence dynamics under the influence of structured vibrational environments. We consider a pump-probe configuration with a linearly polarized pump and a circularly polarized probe, with a variable angle θ between the two directions of propagation. In our theoretical formalism the signal is decomposed in chiral and achiral doorway and window functions. Using this formalism, we show that the chiral doorway component, which beats during the population time, can be isolated by comparing signals with different values of θ. As in the majority of time-resolved pump-probe spectroscopy, the overall TRCD response shows signatures of both excited and ground state dynamics. However, we demonstrate that the chiral doorway function has only a weak ground state contribution, which can generally be neglected if an impulsive pump pulse is used. These findings suggest that the pump-probe configuration of optical TRCD in the impulsive limit has the potential to unambiguously probe quantum coherence beating in the excited state. We present numerical results for theoretical signals in an example dimer system.

  11. Coherence specific signal detection via chiral pump-probe spectroscopy.

    PubMed

    Holdaway, David I H; Collini, Elisabetta; Olaya-Castro, Alexandra

    2016-05-21

    We examine transient circular dichroism (TRCD) spectroscopy as a technique to investigate signatures of exciton coherence dynamics under the influence of structured vibrational environments. We consider a pump-probe configuration with a linearly polarized pump and a circularly polarized probe, with a variable angle θ between the two directions of propagation. In our theoretical formalism the signal is decomposed in chiral and achiral doorway and window functions. Using this formalism, we show that the chiral doorway component, which beats during the population time, can be isolated by comparing signals with different values of θ. As in the majority of time-resolved pump-probe spectroscopy, the overall TRCD response shows signatures of both excited and ground state dynamics. However, we demonstrate that the chiral doorway function has only a weak ground state contribution, which can generally be neglected if an impulsive pump pulse is used. These findings suggest that the pump-probe configuration of optical TRCD in the impulsive limit has the potential to unambiguously probe quantum coherence beating in the excited state. We present numerical results for theoretical signals in an example dimer system. PMID:27208941

  12. Non-additive model for specific heat of electrons

    NASA Astrophysics Data System (ADS)

    Anselmo, D. H. A. L.; Vasconcelos, M. S.; Silva, R.; Mello, V. D.

    2016-10-01

    By using non-additive Tsallis entropy we demonstrate numerically that one-dimensional quasicrystals, whose energy spectra are multifractal Cantor sets, are characterized by an entropic parameter, and calculate the electronic specific heat, where we consider a non-additive entropy Sq. In our method we consider an energy spectra calculated using the one-dimensional tight binding Schrödinger equation, and their bands (or levels) are scaled onto the [ 0 , 1 ] interval. The Tsallis' formalism is applied to the energy spectra of Fibonacci and double-period one-dimensional quasiperiodic lattices. We analytically obtain an expression for the specific heat that we consider to be more appropriate to calculate this quantity in those quasiperiodic structures.

  13. The backscatter electron signal as an additional tool for phase segmentation in electron backscatter diffraction.

    PubMed

    Payton, E J; Nolze, G

    2013-08-01

    The advent of simultaneous energy dispersive X-ray spectroscopy (EDS) data collection has vastly improved the phase separation capabilities for electron backscatter diffraction (EBSD) mapping. A major problem remains, however, in distinguishing between multiple cubic phases in a specimen, especially when the compositions of the phases are similar or their particle sizes are small, because the EDS interaction volume is much larger than that of EBSD and the EDS spectra collected during spatial mapping are generally noisy due to time limitations and the need to minimize sample drift. The backscatter electron (BSE) signal is very sensitive to the local composition due to its atomic number (Z) dependence. BSE imaging is investigated as a complimentary tool to EDS to assist phase segmentation and identification in EBSD through examination of specimens of meteorite, Cu dross, and steel oxidation layers. The results demonstrate that the simultaneous acquisition of EBSD patterns, EDS spectra, and the BSE signal can provide new potential for advancing multiphase material characterization in the scanning electron microscope. PMID:23575349

  14. Detection of electron magnetic circular dichroism signals under zone axial diffraction geometry.

    PubMed

    Song, Dongsheng; Rusz, Jan; Cai, Jianwang; Zhu, Jing

    2016-10-01

    EMCD (electron magnetic circular dichroism) technique provides us a new opportunity to explore magnetic properties in the transmission electron microscope. However, specific diffraction geometry is the major limitation. Only the two-beam and three-beam case are demonstrated in the experiments until now. Here, we present the more general case of zone axial (ZA) diffraction geometry through which the EMCD signals can be detected even with the very strong sensitivity to dynamical diffraction conditions. Our detailed calculations and well-controlled diffraction conditions lead to experiments in agreement with theory. The effect of dynamical diffraction conditions on EMCD signals are discussed both in theory and experiments. Moreover, with the detailed analysis of dynamical diffraction effects, we experimentally obtain the separate EMCD signals for each crystallographic site in Y3Fe5O12, which is also applicable for other materials and cannot be achieved by site-specific EMCD and XMCD technique directly. Our work extends application of more general diffraction geometries and will further promote the development of EMCD technique. PMID:27448200

  15. Phosphatase specificity and pathway insulation in signaling networks.

    PubMed

    Rowland, Michael A; Harrison, Brian; Deeds, Eric J

    2015-02-17

    Phosphatases play an important role in cellular signaling networks by regulating the phosphorylation state of proteins. Phosphatases are classically considered to be promiscuous, acting on tens to hundreds of different substrates. We recently demonstrated that a shared phosphatase can couple the responses of two proteins to incoming signals, even if those two substrates are from otherwise isolated areas of the network. This finding raises a potential paradox: if phosphatases are indeed highly promiscuous, how do cells insulate themselves against unwanted crosstalk? Here, we use mathematical models to explore three possible insulation mechanisms. One approach involves evolving phosphatase KM values that are large enough to prevent saturation by the phosphatase's substrates. Although this is an effective method for generating isolation, the phosphatase becomes a highly inefficient enzyme, which prevents the system from achieving switch-like responses and can result in slow response kinetics. We also explore the idea that substrate degradation can serve as an effective phosphatase. Assuming that degradation is unsaturatable, this mechanism could insulate substrates from crosstalk, but it would also preclude ultrasensitive responses and would require very high substrate turnover to achieve rapid dephosphorylation kinetics. Finally, we show that adaptor subunits, such as those found on phosphatases like PP2A, can provide effective insulation against phosphatase crosstalk, but only if their binding to substrates is uncoupled from their binding to the catalytic core. Analysis of the interaction network of PP2A's adaptor domains reveals that although its adaptors may isolate subsets of targets from one another, there is still a strong potential for phosphatase crosstalk within those subsets. Understanding how phosphatase crosstalk and the insulation mechanisms described here impact the function and evolution of signaling networks represents a major challenge for

  16. Phosphatase Specificity and Pathway Insulation in Signaling Networks

    PubMed Central

    Rowland, Michael A.; Harrison, Brian; Deeds, Eric J.

    2015-01-01

    Phosphatases play an important role in cellular signaling networks by regulating the phosphorylation state of proteins. Phosphatases are classically considered to be promiscuous, acting on tens to hundreds of different substrates. We recently demonstrated that a shared phosphatase can couple the responses of two proteins to incoming signals, even if those two substrates are from otherwise isolated areas of the network. This finding raises a potential paradox: if phosphatases are indeed highly promiscuous, how do cells insulate themselves against unwanted crosstalk? Here, we use mathematical models to explore three possible insulation mechanisms. One approach involves evolving phosphatase KM values that are large enough to prevent saturation by the phosphatase’s substrates. Although this is an effective method for generating isolation, the phosphatase becomes a highly inefficient enzyme, which prevents the system from achieving switch-like responses and can result in slow response kinetics. We also explore the idea that substrate degradation can serve as an effective phosphatase. Assuming that degradation is unsaturatable, this mechanism could insulate substrates from crosstalk, but it would also preclude ultrasensitive responses and would require very high substrate turnover to achieve rapid dephosphorylation kinetics. Finally, we show that adaptor subunits, such as those found on phosphatases like PP2A, can provide effective insulation against phosphatase crosstalk, but only if their binding to substrates is uncoupled from their binding to the catalytic core. Analysis of the interaction network of PP2A’s adaptor domains reveals that although its adaptors may isolate subsets of targets from one another, there is still a strong potential for phosphatase crosstalk within those subsets. Understanding how phosphatase crosstalk and the insulation mechanisms described here impact the function and evolution of signaling networks represents a major challenge for

  17. A nonlinear optoelectronic filter for electronic signal processing.

    PubMed

    Loh, William; Yegnanarayanan, Siva; Ram, Rajeev J; Juodawlkis, Paul W

    2014-01-01

    The conversion of electrical signals into modulated optical waves and back into electrical signals provides the capacity for low-loss radio-frequency (RF) signal transfer over optical fiber. Here, we show that the unique properties of this microwave-photonic link also enable the manipulation of RF signals beyond what is possible in conventional systems. We achieve these capabilities by realizing a novel nonlinear filter, which acts to suppress a stronger RF signal in the presence of a weaker signal independent of their separation in frequency. Using this filter, we demonstrate a relative suppression of 56 dB for a stronger signal having a 1-GHz center frequency, uncovering the presence of otherwise undetectable weaker signals located as close as 3.5 Hz away. The capabilities of the optoelectronic filter break the conventional limits of signal detection, opening up new possibilities for radar and communication systems, and for the field of precision frequency metrology. PMID:24402418

  18. A nonlinear optoelectronic filter for electronic signal processing

    PubMed Central

    Loh, William; Yegnanarayanan, Siva; Ram, Rajeev J.; Juodawlkis, Paul W.

    2014-01-01

    The conversion of electrical signals into modulated optical waves and back into electrical signals provides the capacity for low-loss radio-frequency (RF) signal transfer over optical fiber. Here, we show that the unique properties of this microwave-photonic link also enable the manipulation of RF signals beyond what is possible in conventional systems. We achieve these capabilities by realizing a novel nonlinear filter, which acts to suppress a stronger RF signal in the presence of a weaker signal independent of their separation in frequency. Using this filter, we demonstrate a relative suppression of 56 dB for a stronger signal having a 1-GHz center frequency, uncovering the presence of otherwise undetectable weaker signals located as close as 3.5 Hz away. The capabilities of the optoelectronic filter break the conventional limits of signal detection, opening up new possibilities for radar and communication systems, and for the field of precision frequency metrology. PMID:24402418

  19. Nanogold as a specific marker for electron cryotomography.

    PubMed

    He, Yongning; Jensen, Grant J; Bjorkman, Pamela J

    2009-06-01

    While electron cryotomography (ECT) provides "molecular" resolution, three-dimensional images of unique biological specimens, sample crowdedness, and/or resolution limitations can make it difficult to identify specific macromolecular components. Here we used a 1.4 nm Nanogold cluster specifically attached to the Fc fragment of IgG to monitor its interaction with the neonatal Fc receptor (FcRn), a membrane-bound receptor that transports IgG across cells in acidic intracellular vesicles. ECT was used to image complexes formed by Nanogold-labeled Fc bound to FcRn attached to the outer surface of synthetic liposomes. In the resulting three-dimensional reconstructions, 1.4 nm Nanogold particles were distributed predominantly along the interfaces where 2:1 FcRn-Fc complexes bridged adjacent lipid bilayers. These results demonstrate that the 1.4 nm Nanogold cluster is visible in tomograms of typically thick samples (approximately 250 nm) recorded with defocuses appropriate for large macromolecules and is thus an effective marker.

  20. SUMO Signaling by Hypoxic Inactivation of SUMO-Specific Isopeptidases.

    PubMed

    Kunz, Kathrin; Wagner, Kristina; Mendler, Luca; Hölper, Soraya; Dehne, Nathalie; Müller, Stefan

    2016-09-13

    Post-translational modification of proteins with ubiquitin-like SUMO modifiers is a tightly regulated and highly dynamic process. The SENP family of SUMO-specific isopeptidases comprises six cysteine proteases. They are instrumental in counterbalancing SUMO conjugation, but their regulation is not well understood. We demonstrate that in hypoxic cell extracts, the catalytic activity of SENP family members, in particular SENP1 and SENP3, is inhibited in a rapid and fully reversible process. Comparative mass spectrometry from normoxic and hypoxic cells defines a subset of hypoxia-induced SUMO1 targets, including SUMO ligases RanBP2 and PIAS2, glucose transporter 1, and transcriptional regulators. Among the most strongly induced targets, we identified the transcriptional co-repressor BHLHE40, which controls hypoxic gene expression programs. We provide evidence that SUMOylation of BHLHE40 is reversed by SENP1 and contributes to transcriptional repression of the metabolic master regulator gene PGC-1α. We propose a pathway that connects oxygen-controlled SENP activity to hypoxic reprogramming of metabolism. PMID:27626674

  1. Cytoplasmic nanojunctions between lysosomes and sarcoplasmic reticulum are required for specific calcium signaling

    PubMed Central

    Fameli, Nicola; Ogunbayo, Oluseye A.

    2014-01-01

    Herein we demonstrate how nanojunctions between lysosomes and sarcoplasmic reticulum (L-SR junctions) serve to couple lysosomal activation to regenerative, ryanodine receptor-mediated cellular Ca 2+ waves. In pulmonary artery smooth muscle cells (PASMCs) it has been proposed that nicotinic acid adenine dinucleotide phosphate (NAADP) triggers increases in cytoplasmic Ca 2+ via L-SR junctions, in a manner that requires initial Ca 2+ release from lysosomes and subsequent Ca 2+-induced Ca 2+ release (CICR) via ryanodine receptor (RyR) subtype 3 on the SR membrane proximal to lysosomes. L-SR junction membrane separation has been estimated to be < 400 nm and thus beyond the resolution of light microscopy, which has restricted detailed investigations of the junctional coupling process. The present study utilizes standard and tomographic transmission electron microscopy to provide a thorough ultrastructural characterization of the L-SR junctions in PASMCs. We show that L-SR nanojunctions are prominent features within these cells and estimate that the junctional membrane separation and extension are about 15 nm and 300 nm, respectively. Furthermore, we develop a quantitative model of the L-SR junction using these measurements, prior kinetic and specific Ca 2+ signal information as input data. Simulations of NAADP-dependent junctional Ca 2+ transients demonstrate that the magnitude of these signals can breach the threshold for CICR via RyR3. By correlation analysis of live cell Ca 2+ signals and simulated Ca 2+ transients within L-SR junctions, we estimate that “trigger zones” comprising 60–100 junctions are required to confer a signal of similar magnitude. This is compatible with the 110 lysosomes/cell estimated from our ultrastructural observations. Most importantly, our model shows that increasing the L-SR junctional width above 50 nm lowers the magnitude of junctional [Ca 2+] such that there is a failure to breach the threshold for CICR via RyR3. L-SR junctions are

  2. Molecular Basis of Signaling Specificity of Insulin and IGF Receptors: Neglected Corners and Recent Advances

    PubMed Central

    Siddle, Kenneth

    2011-01-01

    Insulin and insulin-like growth factor (IGF) receptors utilize common phosphoinositide 3-kinase/Akt and Ras/extracellular signal-regulated kinase signaling pathways to mediate a broad spectrum of “metabolic” and “mitogenic” responses. Specificity of insulin and IGF action in vivo must in part reflect expression of receptors and responsive pathways in different tissues but it is widely assumed that it is also determined by the ligand binding and signaling mechanisms of the receptors. This review focuses on receptor-proximal events in insulin/IGF signaling and examines their contribution to specificity of downstream responses. Insulin and IGF receptors may differ subtly in the efficiency with which they recruit their major substrates (IRS-1 and IRS-2 and Shc) and this could influence effectiveness of signaling to “metabolic” and “mitogenic” responses. Other substrates (Grb2-associated binder, downstream of kinases, SH2Bs, Crk), scaffolds (RACK1, β-arrestins, cytohesins), and pathways (non-receptor tyrosine kinases, phosphoinositide kinases, reactive oxygen species) have been less widely studied. Some of these components appear to be specifically involved in “metabolic” or “mitogenic” signaling but it has not been shown that this reflects receptor-preferential interaction. Very few receptor-specific interactions have been characterized, and their roles in signaling are unclear. Signaling specificity might also be imparted by differences in intracellular trafficking or feedback regulation of receptors, but few studies have directly addressed this possibility. Although published data are not wholly conclusive, no evidence has yet emerged for signaling mechanisms that are specifically engaged by insulin receptors but not IGF receptors or vice versa, and there is only limited evidence for differential activation of signaling mechanisms that are common to both receptors. Cellular context, rather than intrinsic receptor activity, therefore appears

  3. Nucleotide-Specific Contrast for DNA Sequencing by Electron Spectroscopy.

    PubMed

    Mankos, Marian; Persson, Henrik H J; N'Diaye, Alpha T; Shadman, Khashayar; Schmid, Andreas K; Davis, Ronald W

    2016-01-01

    DNA sequencing by imaging in an electron microscope is an approach that holds promise to deliver long reads with low error rates and without the need for amplification. Earlier work using transmission electron microscopes, which use high electron energies on the order of 100 keV, has shown that low contrast and radiation damage necessitates the use of heavy atom labeling of individual nucleotides, which increases the read error rates. Other prior work using scattering electrons with much lower energy has shown to suppress beam damage on DNA. Here we explore possibilities to increase contrast by employing two methods, X-ray photoelectron and Auger electron spectroscopy. Using bulk DNA samples with monomers of each base, both methods are shown to provide contrast mechanisms that can distinguish individual nucleotides without labels. Both spectroscopic techniques can be readily implemented in a low energy electron microscope, which may enable label-free DNA sequencing by direct imaging. PMID:27149617

  4. Nucleotide-Specific Contrast for DNA Sequencing by Electron Spectroscopy

    PubMed Central

    Schmid, Andreas K.; Davis, Ronald W.

    2016-01-01

    DNA sequencing by imaging in an electron microscope is an approach that holds promise to deliver long reads with low error rates and without the need for amplification. Earlier work using transmission electron microscopes, which use high electron energies on the order of 100 keV, has shown that low contrast and radiation damage necessitates the use of heavy atom labeling of individual nucleotides, which increases the read error rates. Other prior work using scattering electrons with much lower energy has shown to suppress beam damage on DNA. Here we explore possibilities to increase contrast by employing two methods, X-ray photoelectron and Auger electron spectroscopy. Using bulk DNA samples with monomers of each base, both methods are shown to provide contrast mechanisms that can distinguish individual nucleotides without labels. Both spectroscopic techniques can be readily implemented in a low energy electron microscope, which may enable label-free DNA sequencing by direct imaging. PMID:27149617

  5. A hierarchy of ECM-mediated signalling tissue-specific gene expression regulates tissue-specific gene expression

    SciTech Connect

    Roskelley, Calvin D; Srebrow, Anabella; Bissell, Mina J

    1995-10-07

    A dynamic and reciprocal flow of information between cells and the extracellular matrix contributes significantly to the regulation of form and function in developing systems. Signals generated by the extracellular matrix do not act in isolation. Instead, they are processed within the context of global signalling hierarchies whose constituent inputs and outputs are constantly modulated by all the factors present in the cell's surrounding microenvironment. This is particularly evident in the mammary gland, where the construction and subsequent destruction of such a hierarchy regulates changes in tissue-specific gene expression, morphogenesis and apoptosis during each developmental cycle of pregnancy, lactation and involution.

  6. Specificity is complex and time consuming: mutual exclusivity in tyrosine kinase-mediated signaling.

    PubMed

    O'Rourke, Lisa; Ladbury, John E

    2003-06-01

    Most fundamental cellular processes are transduced through tyrosine kinase (TK)-mediated pathways. For transduction without corruption, the protein-protein interactions involved have to be mutually exclusive. Many of these proteins bind via homologous domains whose binding characteristics suggest that their innate specificity is not sufficiently high to account for the integrity of signal transduction. Stimulation of TK-mediated signals is often accompanied by recruitment of a precise, multimolecular protein complex that is itself capable of imposing specificity. Furthermore, this complex provides protection against phosphatase activity, controlling the longevity of the active signaling complex, and thus influencing outcomes in subsequent downstream events.

  7. Cell-Autonomous Gβ Signaling Defines Neuron-Specific Steady State Serotonin Synthesis in Caenorhabditis elegans.

    PubMed

    Xu, Lu; Choi, Sunju; Xie, Yusu; Sze, Ji Ying

    2015-09-01

    Heterotrimeric G proteins regulate a vast array of cellular functions via specific intracellular effectors. Accumulating pharmacological and biochemical studies implicate Gβ subunits as signaling molecules interacting directly with a wide range of effectors to modulate downstream cellular responses, in addition to their role in regulating Gα subunit activities. However, the native biological roles of Gβ-mediated signaling pathways in vivo have been characterized only in a few cases. Here, we identified a Gβ GPB-1 signaling pathway operating in specific serotonergic neurons to the define steady state serotonin (5-HT) synthesis, through a genetic screen for 5-HT synthesis mutants in Caenorhabditis elegans. We found that signaling through cell autonomous GPB-1 to the OCR-2 TRPV channel defines the baseline expression of 5-HT synthesis enzyme tryptophan hydroxylase tph-1 in ADF chemosensory neurons. This Gβ signaling pathway is not essential for establishing the serotonergic cell fates and is mechanistically separated from stress-induced tph-1 upregulation. We identified that ADF-produced 5-HT controls specific innate rhythmic behaviors. These results revealed a Gβ-mediated signaling operating in differentiated cells to specify intrinsic functional properties, and indicate that baseline TPH expression is not a default generic serotonergic fate, but is programmed in a cell-specific manner in the mature nervous system. Cell-specific regulation of TPH expression could be a general principle for tailored steady state 5-HT synthesis in functionally distinct neurons and their regulation of innate behavior. PMID:26402365

  8. Cell-Autonomous Gβ Signaling Defines Neuron-Specific Steady State Serotonin Synthesis in Caenorhabditis elegans

    PubMed Central

    Xu, Lu; Choi, Sunju; Xie, Yusu; Sze, Ji Ying

    2015-01-01

    Heterotrimeric G proteins regulate a vast array of cellular functions via specific intracellular effectors. Accumulating pharmacological and biochemical studies implicate Gβ subunits as signaling molecules interacting directly with a wide range of effectors to modulate downstream cellular responses, in addition to their role in regulating Gα subunit activities. However, the native biological roles of Gβ-mediated signaling pathways in vivo have been characterized only in a few cases. Here, we identified a Gβ GPB-1 signaling pathway operating in specific serotonergic neurons to the define steady state serotonin (5-HT) synthesis, through a genetic screen for 5-HT synthesis mutants in Caenorhabditis elegans. We found that signaling through cell autonomous GPB-1 to the OCR-2 TRPV channel defines the baseline expression of 5-HT synthesis enzyme tryptophan hydroxylase tph-1 in ADF chemosensory neurons. This Gβ signaling pathway is not essential for establishing the serotonergic cell fates and is mechanistically separated from stress-induced tph-1 upregulation. We identified that ADF-produced 5-HT controls specific innate rhythmic behaviors. These results revealed a Gβ-mediated signaling operating in differentiated cells to specify intrinsic functional properties, and indicate that baseline TPH expression is not a default generic serotonergic fate, but is programmed in a cell-specific manner in the mature nervous system. Cell-specific regulation of TPH expression could be a general principle for tailored steady state 5-HT synthesis in functionally distinct neurons and their regulation of innate behavior. PMID:26402365

  9. Electronic test instrument generates extremely small current signals

    NASA Technical Reports Server (NTRS)

    Brookshier, W. K.

    1967-01-01

    Generator produces dynamic test signals in the range from 0.0001 and 10 to the minus 12th power amperes. It involves an extension of the technique of applying a triangular voltage waveform to a small capacitor to obtain a square-wave output current. The effects of stray capacitance are minimized by appropriate shielding.

  10. Electronic filters, repeated signal charge conversion apparatus, hearing aids and methods

    NASA Technical Reports Server (NTRS)

    Morley, Jr., Robert E. (Inventor); Engebretson, A. Maynard (Inventor); Engel, George L. (Inventor); Sullivan, Thomas J. (Inventor)

    1993-01-01

    An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits associated with the filter stages for storing electrical representations of filter parameters. The filter stages include circuits for respectively adding the electrical representations of the filter parameters to the electrical signal to be filtered thereby producing a set of filter sum signals. At least one of the filter stages includes circuitry for producing a filter signal in substantially logarithmic form at its output by combining a filter sum signal for that filter stage with a signal from an output of another filter stage. The signal processing circuitry produces an intermediate output signal, and a multiplexer connected to the signal processing circuit multiplexes the intermediate output signal with the electrical signal to be filtered so that the logarithmic filter operates as both a logarithmic prefilter and a logarithmic postfilter. Other electronic filters, signal conversion apparatus, electroacoustic systems, hearing aids and methods are also disclosed.

  11. Equalization-enhanced phase noise for coherent-detection systems using electronic digital signal processing.

    PubMed

    Shieh, William; Ho, Keang-Po

    2008-09-29

    In coherent optical systems employing electronic digital signal processing, the fiber chromatic dispersion can be gracefully compensated in electronic domain without resorting to optical techniques. Unlike optical dispersion compensator, the electronic equalizer enhances the impairments from the laser phase noise. This equalization-enhanced phase noise (EEPN) imposes a tighter constraint on the receive laser phase noise for transmission systems with high symbol rate and large electronically-compensated chromatic dispersion.

  12. Cell- and stimulus type-specific intracellular free Ca2+ signals in Arabidopsis.

    PubMed

    Martí, María C; Stancombe, Matthew A; Webb, Alex A R

    2013-10-01

    Appropriate stimulus-response coupling requires that each signal induces a characteristic response, distinct from that induced by other signals, and that there is the potential for individual signals to initiate different downstream responses dependent on cell type. How such specificity is encoded in plant signaling is not known. One possibility is that information is encoded in signal transduction pathways to ensure stimulus- and cell type-specific responses. The calcium ion acts as a second messenger in response to mechanical stimulation, hydrogen peroxide, NaCl, and cold in plants and also in circadian timing. We use GAL4 transactivation of aequorin in enhancer trap lines of Arabidopsis (Arabidopsis thaliana) to test the hypothesis that stimulus- and cell-specific information can be encoded in the pattern of dynamic alterations in the concentration of intracellular free Ca(2+) ([Ca(2+)]i). We demonstrate that mechanically induced increases in [Ca(2+)]i are largely restricted to the epidermal pavement cells of leaves, that NaCl induces oscillatory [Ca(2+)]i signals in spongy mesophyll and vascular bundle cells, but not other cell types, and detect circadian rhythms of [Ca(2+)]i only in the spongy mesophyll. We demonstrate stimulus-specific [Ca(2+)]i dynamics in response to touch, cold, and hydrogen peroxide, which in the case of the latter two signals are common to all cell types tested. GAL4 transactivation of aequorin in specific leaf cell types has allowed us to bypass the technical limitations associated with fluorescent Ca(2+) reporter dyes in chlorophyll-containing tissues to identify the cell- and stimulus-specific complexity of [Ca(2+)]i dynamics in leaves of Arabidopsis and to determine from which tissues stress- and circadian-regulated [Ca(2+)]i signals arise.

  13. Electron dose dependence of signal-to-noise ratio, atom contrast and resolution in transmission electron microscope images.

    PubMed

    Lee, Z; Rose, H; Lehtinen, O; Biskupek, J; Kaiser, U

    2014-10-01

    In order to achieve the highest resolution in aberration-corrected (AC) high-resolution transmission electron microscopy (HRTEM) images, high electron doses are required which only a few samples can withstand. In this paper we perform dose-dependent AC-HRTEM image calculations, and study the dependence of the signal-to-noise ratio, atom contrast and resolution on electron dose and sampling. We introduce dose-dependent contrast, which can be used to evaluate the visibility of objects under different dose conditions. Based on our calculations, we determine optimum samplings for high and low electron dose imaging conditions.

  14. Electron dose dependence of signal-to-noise ratio, atom contrast and resolution in transmission electron microscope images.

    PubMed

    Lee, Z; Rose, H; Lehtinen, O; Biskupek, J; Kaiser, U

    2014-10-01

    In order to achieve the highest resolution in aberration-corrected (AC) high-resolution transmission electron microscopy (HRTEM) images, high electron doses are required which only a few samples can withstand. In this paper we perform dose-dependent AC-HRTEM image calculations, and study the dependence of the signal-to-noise ratio, atom contrast and resolution on electron dose and sampling. We introduce dose-dependent contrast, which can be used to evaluate the visibility of objects under different dose conditions. Based on our calculations, we determine optimum samplings for high and low electron dose imaging conditions. PMID:24566042

  15. Investigation of defects in In–Ga–Zn oxide thin film using electron spin resonance signals

    SciTech Connect

    Nonaka, Yusuke; Kurosawa, Yoichi; Komatsu, Yoshihiro; Ishihara, Noritaka; Oota, Masashi; Nakashima, Motoki; Hirohashi, Takuya; Takahashi, Masahiro; Yamazaki, Shunpei; Obonai, Toshimitsu; Hosaka, Yasuharu; Koezuka, Junichi; Yamauchi, Jun

    2014-04-28

    In–Ga–Zn oxide (IGZO) is a next-generation semiconductor material seen as an alternative to silicon. Despite the importance of the controllability of characteristics and the reliability of devices, defects in IGZO have not been fully understood. We investigated defects in IGZO thin films using electron spin resonance (ESR) spectroscopy. In as-sputtered IGZO thin films, we observed an ESR signal which had a g-value of g = 2.010, and the signal was found to disappear under thermal treatment. Annealing in a reductive atmosphere, such as N{sub 2} atmosphere, generated an ESR signal with g = 1.932 in IGZO thin films. The temperature dependence of the latter signal suggests that the signal is induced by delocalized unpaired electrons (i.e., conduction electrons). In fact, a comparison between the conductivity and ESR signal intensity revealed that the signal's intensity is related to the number of conduction electrons in the IGZO thin film. The signal's intensity did not increase with oxygen vacancy alone but also with increases in both oxygen vacancy and hydrogen concentration. In addition, first-principle calculation suggests that the conduction electrons in IGZO may be generated by defects that occur when hydrogen atoms are inserted into oxygen vacancies.

  16. 77 FR 50726 - Software Requirement Specifications for Digital Computer Software and Complex Electronics Used in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ... COMMISSION Software Requirement Specifications for Digital Computer Software and Complex Electronics Used in... Digital Computer Software and Complex Electronics used in Safety Systems of Nuclear Power Plants.'' The DG... Requirement Specifications for Digital Computer Software and Complex Electronics used in Safety Systems...

  17. Targeting tissue-specific metabolic signaling pathways in aging: the promise and limitations.

    PubMed

    Hu, Fang; Liu, Feng

    2014-01-01

    It has been well established that most of the age-related diseases such as insulin resistance, type 2 diabetes, hypertension, cardiovascular disease, osteoporosis, and atherosclerosis are all closely related to metabolic dysfunction. On the other hand, interventions on metabolism such as calorie restriction or genetic manipulations of key metabolic signaling pathways such as the insulin and mTOR signaling pathways slow down the aging process and improve healthy aging. These findings raise an important question as to whether improving energy homeostasis by targeting certain metabolic signaling pathways in specific tissues could be an effective anti-aging strategy. With a more comprehensive understanding of the tissue-specific roles of distinct metabolic signaling pathways controlling energy homeostasis and the cross-talks between these pathways during aging may lead to the development of more effective therapeutic interventions not only for metabolic dysfunction but also for aging.

  18. An Fgf-Shh signaling hierarchy regulates early specification of the zebrafish skull

    PubMed Central

    McCarthy, Neil; Sidik, Alfire; Bertrand, Julien Y.; Eberhart, Johann K.

    2016-01-01

    The neurocranium generates most of the craniofacial skeleton and consists of prechordal and postchordal regions. Although development of the prechordal is well studied, little is known of the postchordal region. Here we characterize a signaling hierarchy necessary for postchordal neurocranial development involving Fibroblast growth factor (Fgf) signaling for early specification of mesodermally-derived progenitor cells. The expression of hyaluron synthetase 2 (has2) in the cephalic mesoderm requires Fgf signaling and Has2 function, in turn, is required for postchordal neurocranial development. While Hedgehog (Hh)-deficient embryos also lack a postchordal neurocranium, this appears primarily due to a later defect in chondrocyte differentiation. Inhibitor studies demonstrate that postchordal neurocranial development requires early Fgf and later Hh signaling. Collectively, our results provide a mechanistic understanding of early postchordal neurocranial development and demonstrate a hierarchy of signaling between Fgf and Hh in the development of this structure. PMID:27060628

  19. The 20 kilovolt rocket borne electron accelerator. [equipment specifications

    NASA Technical Reports Server (NTRS)

    Harrison, R.

    1973-01-01

    The accelerator system is a preprogrammed multi-voltage system capable of operating at a current level of 1/2 ampere at the 20 kilovolt level. The five major functional areas which comprise this system are: (1) Silver zinc battery packs; (2) the electron gun assembly; (3) gun control and opening circuits; (4) the telemetry conditioning section; and (5) the power conversion section.

  20. Gliolectin positively regulates Notch signalling during wing-vein specification in Drosophila.

    PubMed

    Prasad, Naveen; Shashidhara, Lingadahalli S

    2015-01-01

    Notch signalling is essential for animal development. It integrates multiple pathways controlling cell fate and specification. Here we report the genetic characterization of Gliolectin, presumably a lectin, a cytoplasmic protein, significantly enriched in Golgi bodies. Its expression overlaps with regions where Notch is activated. Loss of gliolectin function results in ectopic veins, while gain of its function causes loss of wing veins. It positively regulates Enhancer of split mβ, a target of Notch signalling. These observations suggest that it is a positive regulator of Notch signalling during wing development in Drosophila. PMID:26505251

  1. SUMOylation of AMPKα1 by PIAS4 specifically regulates mTORC1 signalling

    PubMed Central

    Yan, Yan; Ollila, Saara; Wong, Iris P. L.; Vallenius, Tea; Palvimo, Jorma J.; Vaahtomeri, Kari; Mäkelä, Tomi P.

    2015-01-01

    AMP-activated protein kinase (AMPK) inhibits several anabolic pathways such as fatty acid and protein synthesis, and identification of AMPK substrate specificity would be useful to understand its role in particular cellular processes and develop strategies to modulate AMPK activity in a substrate-specific manner. Here we show that SUMOylation of AMPKα1 attenuates AMPK activation specifically towards mTORC1 signalling. SUMOylation is also important for rapid inactivation of AMPK, to allow prompt restoration of mTORC1 signalling. PIAS4 and its SUMO E3 ligase activity are specifically required for the AMPKα1 SUMOylation and the inhibition of AMPKα1 activity towards mTORC1 signalling. The activity of a SUMOylation-deficient AMPKα1 mutant is higher than the wild type towards mTORC1 signalling when reconstituted in AMPKα-deficient cells. PIAS4 depletion reduced growth of breast cancer cells, specifically when combined with direct AMPK activator A769662, suggesting that inhibiting AMPKα1 SUMOylation can be explored to modulate AMPK activation and thereby suppress cancer cell growth. PMID:26616021

  2. Low Background Signal Readout Electronics for the Majorana Demonstrator

    DOE PAGES

    Guinn, I.; Abgrall, N.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Brudanin, V.; Busch, M.; Buuck, M.; Byram, D.; Caldwell, A. S.; et al

    2015-05-01

    The Majorana Demonstrator is a planned 40 kg array of Germanium detectors intended to demonstrate the feasibility of constructing a tonne-scale experiment that will seek neutrinoless double beta decay (0νββ) in 76Ge. In such an experiment we require backgrounds of less than 1 count/tonne-year in the 4 keV region of interest around the 2039 keV Q-value of the ββ decay. Moreover, designing low-noise electronics, which must be placed in close proximity to the detectors, presents a challenge to reaching this background target. Finally, this paper will discuss the Majorana collaboration's solutions to some of these challenges.

  3. Sequence-specific targeting of nuclear signal transduction pathways by homeodomain proteins.

    PubMed Central

    Grueneberg, D A; Simon, K J; Brennan, K; Gilman, M

    1995-01-01

    Cells translate extracellular signals into specific programs of gene expression that reflect their developmental history or identity. We present evidence that one way this interpretation may be performed is by cooperative interactions between serum response factor (SRF) and certain homeodomain proteins. We show that human and Drosophila homeodomain proteins of the paired class have the ability to recruit SRF to DNA sequences not efficiently recognized by SRF on its own, thereby imparting to a linked reporter gene the potential to respond to polypeptide growth factors. This activity requires both the DNA-binding activity of the homeodomain and putative protein-protein contact residues on the exposed surfaces of homeodomain helices 1 and 2. The ability of the homeodomain to impart signal responsiveness is DNA sequence specific, and this specificity differs from the simple DNA-binding specificity of the homeodomain in vitro. The homeodomain imparts response to a spectrum of signals characteristic of the natural SRF-binding site in the c-fos gene. Response to some of these signals is dependent on the secondary recruitment of SRF-dependent ternary complex factors, and we show directly that a homeodomain can promote the recruitment of one such factor, Elk1. We infer that SRF and homeodomains interact cooperatively on DNA and that formation of SRF-homeodomain complexes permits the recruitment of signal-responsive SRF accessory proteins. The ability to route extracellular signals to specific target genes is a novel activity of the homeodomain, which may contribute to the identity function displayed by many homeodomain genes. PMID:7760827

  4. Position Sensor with Integrated Signal-Conditioning Electronics on a Printed Wiring Board

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C. (Inventor); Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    2001-01-01

    A position sensor, such as a rotary position sensor, includes the signal-conditioning electronics in the housing. The signal-conditioning electronics are disposed on a printed wiring board, which is assembled with another printed wiring board including the sensor windings to provide a sub-assembly. A mu-metal shield is interposed between the printed wiring boards to prevent magnetic interference. The sub-assembly is disposed in the sensor housing adjacent to an inductor board which turns on a shaft. The inductor board emanates an internally or externally generated excitation signal that induces a signal in the sensor windings. The induced signal represents the rotary position of the inductor board relative to the sensor winding board.

  5. Specificity in S-Nitrosylation: A Short-Range Mechanism for NO Signaling?

    PubMed Central

    Araújo, Inês M.; Izquierdo-Álvarez, Alicia; Hernansanz-Agustín, Pablo; Lamas, Santiago; Serrador, Juan M.

    2013-01-01

    Abstract Significance: Nitric oxide (NO) classical and less classical signaling mechanisms (through interaction with soluble guanylate cyclase and cytochrome c oxidase, respectively) operate through direct binding of NO to protein metal centers, and rely on diffusibility of the NO molecule. S-Nitrosylation, a covalent post-translational modification of protein cysteines, has emerged as a paradigm of nonclassical NO signaling. Recent Advances: Several nonenzymatic mechanisms for S-nitrosylation formation and destruction have been described. Enzymatic mechanisms for transnitrosylation and denitrosylation have been also studied as regulators of the modification of specific subsets of proteins. The advancement of modification-specific proteomic methodologies has allowed progress in the study of diverse S-nitrosoproteomes, raising clues and questions about the parameters for determining the protein specificity of the modification. Critical Issues: We propose that S-nitrosylation is mainly a short-range mechanism of NO signaling, exerted in a relatively limited range of action around the NO sources, and tightly related to the very controlled regulation of subcellular localization of nitric oxide synthases. We review the nonenzymatic and enzymatic mechanisms that support this concept, as well as physiological examples of mammalian systems that illustrate well the precise compartmentalization of S-nitrosylation. Future Directions: Individual and proteomic studies of protein S-nitrosylation-based signaling should take into account the subcellular localization in order to gain further insight into the functional role of this modification in (patho)physiological settings. Antioxid. Redox Signal. 19, 1220–1235. PMID:23157283

  6. Signals of strong electronic correlation in ion scattering processes

    NASA Astrophysics Data System (ADS)

    Bonetto, F.; Gonzalez, C.; Goldberg, E. C.

    2016-05-01

    Previous measurements of neutral atom fractions for S r+ scattered by gold polycrystalline surfaces show a singular dependence with the target temperature. There is still not a theoretical model that can properly describe the magnitude and the temperature dependence of the neutralization probabilities found. Here, we applied a first-principles quantum-mechanical theoretical formalism to describe the time-dependent scattering process. Three different electronic correlation approaches consistent with the system analyzed are used: (i) the spinless approach, where two charge channels are considered (S r0 and S r+ ) and the spin degeneration is neglected; (ii) the infinite-U approach, with the same charge channels (S r0 and S r+ ) but considering the spin degeneration; and (iii) the finite-U approach, where the first ionization and second ionization energy levels are considered very, but finitely, separated. Neutral fraction magnitudes and temperature dependence are better described by the finite-U approach, indicating that e -correlation plays a significant role in charge-transfer processes. However, none of them is able to explain the nonmonotonous temperature dependence experimentally obtained. Here, we suggest that small changes in the surface work function introduced by the target heating, and possibly not detected by experimental standard methods, could be responsible for that singular behavior. Additionally, we apply the same theoretical model using the infinite-U approximation for the Mg-Au system, obtaining an excellent description of the experimental neutral fractions measured.

  7. Construction of cell type-specific logic models of signaling networks using CellNOpt.

    PubMed

    Morris, Melody K; Melas, Ioannis; Saez-Rodriguez, Julio

    2013-01-01

    Mathematical models are useful tools for understanding protein signaling networks because they provide an integrated view of pharmacological and toxicological processes at the molecular level. Here we describe an approach previously introduced based on logic modeling to generate cell-specific, mechanistic and predictive models of signal transduction. Models are derived from a network encoding prior knowledge that is trained to signaling data, and can be either binary (based on Boolean logic) or quantitative (using a recently developed formalism, constrained fuzzy logic). The approach is implemented in the freely available tool CellNetOptimizer (CellNOpt). We explain the process CellNOpt uses to train a prior knowledge network to data and illustrate its application with a toy example as well as a realistic case describing signaling networks in the HepG2 liver cancer cell line.

  8. Direct Signal-to-Noise Quality Comparison between an Electronic and Conventional Stethoscope aboard the International Space Station

    NASA Technical Reports Server (NTRS)

    Marshburn, Thomas; Cole, Richard; Ebert, Doug; Bauer, Pete

    2014-01-01

    Introduction: Evaluation of heart, lung, and bowel sounds is routinely performed with the use of a stethoscope to help detect a broad range of medical conditions. Stethoscope acquired information is even more valuable in a resource limited environments such as the International Space Station (ISS) where additional testing is not available. The high ambient noise level aboard the ISS poses a specific challenge to auscultation by stethoscope. An electronic stethoscope's ambient noise-reduction, greater sound amplification, recording capabilities, and sound visualization software may be an advantage to a conventional stethoscope in this environment. Methods: A single operator rated signal-to-noise quality from a conventional stethoscope (Littman 2218BE) and an electronic stethoscope (Litmann 3200). Borborygmi, pulmonic, and cardiac sound quality was ranked with both stethoscopes. Signal-to-noise rankings were preformed on a 1 to 10 subjective scale with 1 being inaudible, 6 the expected quality in an emergency department, 8 the expected quality in a clinic, and 10 the clearest possible quality. Testing took place in the Japanese Pressurized Module (JPM), Unity (Node 2), Destiny (US Lab), Tranquility (Node 3), and the Cupola of the International Space Station. All examinations were conducted at a single point in time. Results: The electronic stethoscope's performance ranked higher than the conventional stethoscope for each body sound in all modules tested. The electronic stethoscope's sound quality was rated between 7 and 10 in all modules tested. In comparison, the traditional stethoscope's sound quality was rated between 4 and 7. The signal to noise ratio of borborygmi showed the biggest difference between stethoscopes. In the modules tested, the auscultation of borborygmi was rated between 5 and 7 by the conventional stethoscope and consistently 10 by the electronic stethoscope. Discussion: This stethoscope comparison was limited to a single operator. However, we

  9. Low Background Signal Readout Electronics for the MAJORANA DEMONSTRATOR

    SciTech Connect

    Guinn, I.; Abgrall, N.; Arnquist, Isaac J.; Avignone, Frank T.; Baldenegro-Barrera, C. X.; Barabash, Alexander S.; Bertrand, F.; Bradley, A. W.; Brudanin, V.; Busch, Matthew; Buuck, M.; Byram, D.; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, C. D.; Cuesta, C.; Detwiler, Jason A.; Efremenko, Yuri; Ejiri, H.; Elliott, Steven R.; Galindo-Uribarri, A.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Henning, Reyco; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Jasinski, B. R.; Keeter, K.; Kidd, M. F.; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; MacMullin, J.; Martin, R. D.; Meijer, S. J.; Mertens, S.; Orrell, John L.; O'Shaughnessy, C.; Poon, Alan; Radford, D. C.; Rager, J.; Rielage, Keith; Robertson, R. G. H.; Romero-Romero, E.; Shanks, B.; Shirchenko, M.; Snyder, N.; Suriano, Anne-Marie; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, Chang-Hong; Yumatov, Vladimir; Zhitnikov, I.

    2015-03-18

    The Majorana Demonstrator (MJD)[1] is an array of p-type point contact (PPC) high purity Germanium (HPGe) detectors intended to search for neutrinoless double beta decay (0vBB decay) in 76Ge. MJD will consist of 40 kg of detectors, 30 kg of which will be isotopically enriched to 87% 76Ge. The array will consist of 14 strings of four or ve detectors placed in two separate cryostats. One of the main goals of the experiment is to demonstrate the feasibility of building a tonne-scale array of detectors to search for 0vBB decay with a much higher sensitivity. This involves acheiving backgrounds in the 4 keV region of interest (ROI) around the 2039 keV Q-value of the BB decay of less than 1 count/ROI-t-y. Because many backgrounds will not directly scale with detector mass, the specific background goal of MJD is less than 3 counts/ROI-t-y.

  10. Socs36E attenuates STAT signaling to optimize motile cell specification in the Drosophila ovary.

    PubMed

    Monahan, Amanda J; Starz-Gaiano, Michelle

    2013-07-15

    The Janus kinase/Signal transducers and activators of transcription (JAK/STAT) pathway determines cell fates by regulating gene expression. One example is the specification of the motile cells called border cells during Drosophila oogenesis. It has been established that too much or too little STAT activity disrupts follicle cell identity and cell motility, which suggests the signaling must be precisely regulated. Here, we find that Suppressor of cytokine signaling at 36E (Socs36E) is a necessary negative regulator of JAK/STAT signaling during border cell specification. We find when STAT signaling is too low to induce migration in the presumptive border cell population, nearby follicle cells uncharacteristically become invasive to enable efficient migration of the cluster. We generated a genetic null allele that reveals Socs36E is required in the anterior follicle cells to limit invasive behavior to an optimal number of cells. We further show Socs36E genetically interacts with the required STAT feedback inhibitor apontic (apt) and APT's downstream target, mir-279, and provide evidence that suggests APT directly regulates Socs36E transcriptionally. Our work shows Socs36E plays a critical role in a genetic circuit that establishes a boundary between the motile border cell cluster and its non-invasive epithelial neighbors through STAT attenuation. PMID:23583584

  11. Analysis of circadian pattern reveals tissue-specific alternative transcription in leptin signaling pathway

    PubMed Central

    Ptitsyn, Andrey A; Gimble, Jeffrey M

    2007-01-01

    Background It has been previously reported that most mammalian genes display a circadian oscillation in their baseline expression. Consequently, the phase and amplitude of each component of a signal transduction cascade has downstream consequences. Results Here, we report our analysis of alternative transcripts in the leptin signaling pathway which is responsible for the systemic regulation of macronutrient storage and energy balance. We focused on the circadian expression pattern of a critical component of the leptin signaling system, suppressor of cytokine signaling 3 (SOCS3). On an Affymetrix GeneChip 430A2 microarray, this gene is represented by three probe sets targeting different regions within the 3' end of the last exon. We demonstrate that in murine brown adipose tissue two downstream 3' probe sets experience circadian baseline oscillation in counter-phase to the upstream probe set. Such differences in expression patterns are a telltale sign of alternative splicing within the last exon of SOCS3. In contrast, all three probe sets oscillated in a common phase in murine liver and white adipose tissue. This suggests that the regulation of SOCS3 expression in brown fat is tissue specific. Another component of the signaling pathway, Janus kinase (JAK), is directly regulated by SOCS and has alternative transcript probe sets oscillating in counter-phase in a white adipose tissue specific manner. Conclusion We hypothesize that differential oscillation of alternative transcripts may provide a mechanism to maintain steady levels of expression in spite of circadian baseline variation. PMID:18047714

  12. Cell-specific STORM superresolution imaging reveals nanoscale organization of cannabinoid signaling

    PubMed Central

    Szabó, Szilárd I.; Szabadits, Eszter; Pintér, Balázs; Woodhams, Stephen G.; Henstridge, Christopher M.; Balla, Gyula Y.; Nyilas, Rita; Varga, Csaba; Lee, Sang-Hun; Matolcsi, Máté; Cervenak, Judit; Kacskovics, Imre; Watanabe, Masahiko; Sagheddu, Claudia; Melis, Miriam; Pistis, Marco; Soltesz, Ivan; Katona, István

    2014-01-01

    A major challenge in neuroscience is to determine the nanoscale position and quantity of signaling molecules in a cell-type-, and subcellular compartment-specific manner. We therefore developed a novel approach combining cell-specific physiological and anatomical characterization with superresolution imaging, and studied the molecular and structural parameters shaping the physiological properties of synaptic endocannabinoid signaling in the mouse hippocampus. We found that axon terminals of perisomatically-projecting GABAergic interneurons possess increased CB1 receptor number, active-zone complexity, and receptor/effector ratio compared to dendritically-projecting interneurons, in agreement with higher efficiency of cannabinoid signaling at somatic versus dendritic synapses. Furthermore, chronic Δ9-tetrahydrocannabinol administration, which reduces cannabinoid efficacy on GABA release, evoked dramatic CB1-downregulation in a dose-dependent manner. Full receptor recovery required several weeks after cessation of Δ9-tetrahydrocannabinol treatment. These findings demonstrate that cell-type-specific nanoscale analysis of endogenous protein distribution is possible in brain circuits, and identify novel molecular properties controlling endocannabinoid signaling and cannabis-induced cognitive dysfunction. PMID:25485758

  13. Mechanisms by which the inhibition of specific intracellular signaling pathways increase osteoblast proliferation on apatite surfaces.

    PubMed

    Yang, Seungwon; Tian, Yu-Shun; Lee, Yun-Jung; Yu, Frank H; Kim, Hyun-Man

    2011-04-01

    Osteoblasts proliferate slowly on the surface of calcium phosphate apatite which is widely used as a substrate biomaterial in bone regeneration. Owing to poor adhesion signaling in the cells grown on the calcium phosphate surface, inadequate growth factor signaling is generated to trigger cell cycle progression. The present study investigated an intracellular signal transduction pathway involved in the slow cell proliferation in osteoblasts grown on the calcium phosphate surface. Small GTPase RhoA and phosphatase and tensin homolog (PTEN) were more activated in cells grown on the surface of calcium phosphate apatite than on tissue culture plate. Specific inhibition of RhoA and PTEN induced the cells on calcium phosphate apatite surface to proliferate at a similar rate as cells on tissue culture plate surface. Specific inhibition of ROCK, which is a downstream effector of RhoA and an upstream activator of PTEN also increased proliferation of these osteoblasts. Present results indicate that physical property of calcium phosphate crystals that impede cell proliferation may be surmounted by the inhibition of the RhoA/ROCK/PTEN pathway to rescue delayed proliferation of osteoblasts on the calcium phosphate apatite surface. In addition, specific inhibition of ROCK promoted cell migration and osteoblast differentiation. Inhibition of the RhoA/ROCK/PTEN intracellular signaling pathway is expected to enhance cell activity to promote and accelerate bone regeneration on the calcium phosphate apatite surface.

  14. Chronic FLT3-ITD Signaling in Acute Myeloid Leukemia Is Connected to a Specific Chromatin Signature

    PubMed Central

    Cauchy, Pierre; James, Sally R.; Zacarias-Cabeza, Joaquin; Ptasinska, Anetta; Imperato, Maria Rosaria; Assi, Salam A.; Piper, Jason; Canestraro, Martina; Hoogenkamp, Maarten; Raghavan, Manoj; Loke, Justin; Akiki, Susanna; Clokie, Samuel J.; Richards, Stephen J.; Westhead, David R.; Griffiths, Michael J.; Ott, Sascha; Bonifer, Constanze; Cockerill, Peter N.

    2015-01-01

    Summary Acute myeloid leukemia (AML) is characterized by recurrent mutations that affect the epigenetic regulatory machinery and signaling molecules, leading to a block in hematopoietic differentiation. Constitutive signaling from mutated growth factor receptors is a major driver of leukemic growth, but how aberrant signaling affects the epigenome in AML is less understood. Furthermore, AML cells undergo extensive clonal evolution, and the mutations in signaling genes are often secondary events. To elucidate how chronic growth factor signaling alters the transcriptional network in AML, we performed a system-wide multi-omics study of primary cells from patients suffering from AML with internal tandem duplications in the FLT3 transmembrane domain (FLT3-ITD). This strategy revealed cooperation between the MAP kinase (MAPK) inducible transcription factor AP-1 and RUNX1 as a major driver of a common, FLT3-ITD-specific gene expression and chromatin signature, demonstrating a major impact of MAPK signaling pathways in shaping the epigenome of FLT3-ITD AML. PMID:26212328

  15. Reusable and specific proton transfer signalling by inorganic cyanide in solution and solid phase.

    PubMed

    Kaloo, Masood Ayoub; Sankar, Jeyaraman

    2015-10-01

    A highly specific cyanide mediated proton transfer signalling (PTS) is exhibited by a simple diaminomalenonitrile (DAMN) derivative 1. By virtue of the functional groups on it, the chromophore offered a rigid anchoring on a silica surface via a simple dip method, while retaining the recognition behaviour. The PTS triggered a prompt dual-modal display i.e., chromogenic and fluorogenic. The signal readout can be visualized even in micromolar concentrations. It is noteworthy that PTS can be reversed in both solution and solid phases. The remarkable sensitivity of 1 to detect CN(-) from the solution and solid phase envisages a pivotal step towards field-usable sensing.

  16. Precise measurement method for ionospheric total electron content using signals from GPS satellites

    NASA Technical Reports Server (NTRS)

    Imae, Michito; Kiuchi, Hitoshi; Kaneko, Akihiro; Hama, Shinichi; Miki, Chihiro

    1990-01-01

    A GPS codeless receiver called GTR-2 was for measuring total electron content (TEC) along the line of sight to the GPS satellite by using the cross correlation amplitude of the received P-code signals carried by L1(1575.42 MHz) and L2(1227.6 MHz). This equipment has the performance of uncertainty in the measurement of TEC of about 2 X 10(exp 16) electrons/sq m when a 10 dBi gain antenna was used. To increase the measurement performance, an upper version of GTR-2 called GTR-3 is planned which uses the phase information of the continuous signals obtained by making a cross correlation or multiplication of the received L1 and L2 P-code signals. By using the difference of these measured phases values, the ionospheric delay with the ambiguities of the periods of L1+L2 and L1-L2 signals can be estimated.

  17. Electron Signal Detection for the Beam-Finder Wire of the Linac Coherent Light Source Undulator

    SciTech Connect

    Wu, Juhao; Emma, P.; Field, R.C.; /SLAC

    2006-09-21

    The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) based on the final kilometer of the Stanford Linear Accelerator. The tight tolerances for positioning the electron beam close to the undulator axis calls for the introduction of Beam Finder Wire (BFW) device. A BFW device close to the upstream end of the undulator segment and a quadrupole close to the down stream end of the undulator segment will allow a beam-based undulator segment alignment. Based on the scattering of the electrons on the BFW, we can detect the electron signal in the main dump bends after the undulator to find the beam position. We propose to use a threshold Cherenkov counter for this purpose. According to the signal strength at such a Cherenkov counter, we then suggest choice of material and size for such a BFW device in the undulator.

  18. Signaling, Regulation, and Specificity of the Type II p21-activated Kinases*

    PubMed Central

    Ha, Byung Hak; Morse, Elizabeth M.; Turk, Benjamin E.; Boggon, Titus J.

    2015-01-01

    The p21-activated kinases (PAKs) are a family of six serine/threonine kinases that act as key effectors of RHO family GTPases in mammalian cells. PAKs are subdivided into two groups: type I PAKs (PAK1, PAK2, and PAK3) and type II PAKs (PAK4, PAK5, and PAK6). Although these groups are involved in common signaling pathways, recent work indicates that the two groups have distinct modes of regulation and have both unique and common substrates. Here, we review recent insights into the molecular level details that govern regulation of type II PAK signaling. We also consider mechanisms by which signal transduction is regulated at the level of substrate specificity. Finally, we discuss the implications of these studies for clinical targeting of these kinases. PMID:25855792

  19. Specificity of MAP kinase signaling in yeast differentiation involves transient versus sustained MAPK activation.

    PubMed

    Sabbagh, W; Flatauer, L J; Bardwell, A J; Bardwell, L

    2001-09-01

    Signals transmitted by common components often elicit distinct (yet appropriate) outcomes. In yeast, two developmental options-mating and invasive growth-are both regulated by the same MAP kinase cascade. Specificity has been thought to result from specialized roles for the two MAP kinases, Kss1 and Fus3, and because Fus3 prevents Kss1 from gaining access to the mating pathway. Kss1 has been thought to participate in mating only when Fus3 is absent. Instead, we show that Kss1 is rapidly phosphorylated and potently activated by mating pheromone in wild-type cells, and that this is required for normal pheromone-induced gene expression. Signal identity is apparently maintained because active Fus3 limits the extent of Kss1 activation, thereby preventing inappropriate signal crossover. PMID:11583629

  20. Delivery of circulating lipoproteins to specific neurons in the Drosophila brain regulates systemic insulin signaling

    PubMed Central

    Brankatschk, Marko; Dunst, Sebastian; Nemetschke, Linda; Eaton, Suzanne

    2014-01-01

    The Insulin signaling pathway couples growth, development and lifespan to nutritional conditions. Here, we demonstrate a function for the Drosophila lipoprotein LTP in conveying information about dietary lipid composition to the brain to regulate Insulin signaling. When yeast lipids are present in the diet, free calcium levels rise in Blood Brain Barrier glial cells. This induces transport of LTP across the Blood Brain Barrier by two LDL receptor-related proteins: LRP1 and Megalin. LTP accumulates on specific neurons that connect to cells that produce Insulin-like peptides, and induces their release into the circulation. This increases systemic Insulin signaling and the rate of larval development on yeast-containing food compared with a plant-based food of similar nutritional content. DOI: http://dx.doi.org/10.7554/eLife.02862.001 PMID:25275323

  1. The effect of electron beam geometric deformation errors on the small-signal characteristic of ECRM

    NASA Astrophysics Data System (ADS)

    Yongjian, Yu

    1993-08-01

    In this paper is studied the effect of electron beam geometric deformation errors on the small — signal characteristics of the TE{mn/o} mode Electron Cyclotron Resonance Maser (ECRM), based on the elliptically cross—sectional e—beam deformation model. As an example, the effect of small geometric deformation errors on the TE{01/o} mode fundamental ECRM coupling coefficient is quantitatively shown.

  2. Tissue-Specific Gain of RTK Signalling Uncovers Selective Cell Vulnerability during Embryogenesis

    PubMed Central

    Audebert, Stéphane; Helmbacher, Françoise; Dono, Rosanna; Maina, Flavio

    2015-01-01

    The successive events that cells experience throughout development shape their intrinsic capacity to respond and integrate RTK inputs. Cellular responses to RTKs rely on different mechanisms of regulation that establish proper levels of RTK activation, define duration of RTK action, and exert quantitative/qualitative signalling outcomes. The extent to which cells are competent to deal with fluctuations in RTK signalling is incompletely understood. Here, we employ a genetic system to enhance RTK signalling in a tissue-specific manner. The chosen RTK is the hepatocyte growth factor (HGF) receptor Met, an appropriate model due to its pleiotropic requirement in distinct developmental events. Ubiquitously enhanced Met in Cre/loxP-based Rosa26 stopMet knock-in context (Del-R26 Met) reveals that most tissues are capable of buffering enhanced Met-RTK signalling thus avoiding perturbation of developmental programs. Nevertheless, this ubiquitous increase of Met does compromise selected programs such as myoblast migration. Using cell-type specific Cre drivers, we genetically showed that altered myoblast migration results from ectopic Met expression in limb mesenchyme rather than in migrating myoblasts themselves. qRT-PCR analyses show that ectopic Met in limbs causes molecular changes such as downregulation in the expression levels of Notum and Syndecan4, two known regulators of morphogen gradients. Molecular and functional studies revealed that ectopic Met expression in limb mesenchyme does not alter HGF expression patterns and levels, but impairs HGF bioavailability. Together, our findings show that myoblasts, in which Met is endogenously expressed, are capable of buffering increased RTK levels, and identify mesenchymal cells as a cell type vulnerable to ectopic Met-RTK signalling. These results illustrate that embryonic cells are sensitive to alterations in the spatial distribution of RTK action, yet resilient to fluctuations in signalling levels of an RTK when occurring

  3. Batteryless wireless transmission system for electronic drum uses piezoelectric generator for play signal and power source

    NASA Astrophysics Data System (ADS)

    Nishikawa, H.; Yoshimi, A.; Takemura, K.; Tanaka, A.; Douseki, T.

    2015-12-01

    A batteryless self-powered wireless transmission system has been developed that sends a signal from a drum pad to a synthesizer. The power generated by a piezoelectric generator functions both as the “Play” signal for the synthesizer and as the power source for the transmitter. An FM transmitter, which theoretically operates with zero latency, and a receiver with quick-response squelch of the received signal were developed for wireless transmission with a minimum system delay. Experimental results for an electronic drum without any connecting wires fully demonstrated the feasibility of self-powered wireless transmission with a latency of 900 μs.

  4. Specification of the mouse cardiac conduction system in the absence of Endothelin signaling.

    PubMed

    Hua, Lisa L; Vedantham, Vasanth; Barnes, Ralston M; Hu, Jianxin; Robinson, Ashley S; Bressan, Michael; Srivastava, Deepak; Black, Brian L

    2014-09-15

    Coordinated contraction of the heart is essential for survival and is regulated by the cardiac conduction system. Contraction of ventricular myocytes is controlled by the terminal part of the conduction system known as the Purkinje fiber network. Lineage analyses in chickens and mice have established that the Purkinje fibers of the peripheral ventricular conduction system arise from working myocytes during cardiac development. It has been proposed, based primarily on gain-of-function studies, that Endothelin signaling is responsible for myocyte-to-Purkinje fiber transdifferentiation during avian heart development. However, the role of Endothelin signaling in mammalian conduction system development is less clear, and the development of the cardiac conduction system in mice lacking Endothelin signaling has not been previously addressed. Here, we assessed the specification of the cardiac conduction system in mouse embryos lacking all Endothelin signaling. We found that mouse embryos that were homozygous null for both ednra and ednrb, the genes encoding the two Endothelin receptors in mice, were born at predicted Mendelian frequency and had normal specification of the cardiac conduction system and apparently normal electrocardiograms with normal QRS intervals. In addition, we found that ednra expression within the heart was restricted to the myocardium while ednrb expression in the heart was restricted to the endocardium and coronary endothelium. By establishing that ednra and ednrb are expressed in distinct compartments within the developing mammalian heart and that Endothelin signaling is dispensable for specification and function of the cardiac conduction system, this work has important implications for our understanding of mammalian cardiac development.

  5. Signalling pathways mediating specific synergistic interactions between GDF9 and BMP15.

    PubMed

    Mottershead, David G; Ritter, Lesley J; Gilchrist, Robert B

    2012-03-01

    Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are two proteins selectively expressed in the oocyte which are essential for normal fertility. Both of these proteins are members of the transforming growth factor beta (TGF-β) superfamily and as such are produced as pre-proproteins, existing after proteolytic processing as a complex of the respective pro and mature regions. Previous work has shown that these two proteins interact both at the genetic and cellular signalling levels. In this study, our aim was to determine if the purified mature regions of GDF9 and BMP15 exhibit synergistic interactions on granulosa cells and to determine if such interactions are specific to these two proteins. We have used primary cultures of murine granulosa cells and [(3)H]-thymidine incorporation or transcriptional reporter assays as our readouts. We observed clear synergistic interactions between the mature regions of GDF9 and BMP15 when either DNA synthesis or SMAD3 signalling were examined. GDF9/BMP15 synergistic interactions were specific such that neither factor could be replaced by an analogous TGF-β superfamily member. The GDF9/BMP15 synergistic signalling response was inhibited by the SMAD2/3 phosphorylation inhibitor SB431542, as well as inhibition of the mitogen-activated protein kinase or rous sarcoma oncogene (SRC) signalling pathways, but not the nuclear factor kappa B pathway. In this study, we show that purified mature regions of GDF9 and BMP15 synergistically interact in a specific manner which is not dependent on the presence of a pro-region. This synergistic interaction is targeted at the SMAD3 pathway, and is dependent on ERK1/2 and SRC kinase signalling.

  6. Tissue-Specific Suppression of Thyroid Hormone Signaling in Various Mouse Models of Aging.

    PubMed

    Visser, W Edward; Bombardieri, Cíntia R; Zevenbergen, Chantal; Barnhoorn, Sander; Ottaviani, Alexandre; van der Pluijm, Ingrid; Brandt, Renata; Kaptein, Ellen; van Heerebeek, Ramona; van Toor, Hans; Garinis, George A; Peeters, Robin P; Medici, Marco; van Ham, Willy; Vermeij, Wilbert P; de Waard, Monique C; de Krijger, Ronald R; Boelen, Anita; Kwakkel, Joan; Kopchick, John J; List, Edward O; Melis, Joost P M; Darras, Veerle M; Dollé, Martijn E T; van der Horst, Gijsbertus T J; Hoeijmakers, Jan H J; Visser, Theo J

    2016-01-01

    DNA damage contributes to the process of aging, as underscored by premature aging syndromes caused by defective DNA repair. Thyroid state changes during aging, but underlying mechanisms remain elusive. Since thyroid hormone (TH) is a key regulator of metabolism, changes in TH signaling have widespread effects. Here, we reveal a significant common transcriptomic signature in livers from hypothyroid mice, DNA repair-deficient mice with severe (Csbm/m/Xpa-/-) or intermediate (Ercc1-/Δ-7) progeria and naturally aged mice. A strong induction of TH-inactivating deiodinase D3 and decrease of TH-activating D1 activities are observed in Csbm/m/Xpa-/- livers. Similar findings are noticed in Ercc1-/Δ-7, in naturally aged animals and in wild-type mice exposed to a chronic subtoxic dose of DNA-damaging agents. In contrast, TH signaling in muscle, heart and brain appears unaltered. These data show a strong suppression of TH signaling in specific peripheral organs in premature and normal aging, probably lowering metabolism, while other tissues appear to preserve metabolism. D3-mediated TH inactivation is unexpected, given its expression mainly in fetal tissues. Our studies highlight the importance of DNA damage as the underlying mechanism of changes in thyroid state. Tissue-specific regulation of deiodinase activities, ensuring diminished TH signaling, may contribute importantly to the protective metabolic response in aging. PMID:26953569

  7. Tissue-Specific Suppression of Thyroid Hormone Signaling in Various Mouse Models of Aging.

    PubMed

    Visser, W Edward; Bombardieri, Cíntia R; Zevenbergen, Chantal; Barnhoorn, Sander; Ottaviani, Alexandre; van der Pluijm, Ingrid; Brandt, Renata; Kaptein, Ellen; van Heerebeek, Ramona; van Toor, Hans; Garinis, George A; Peeters, Robin P; Medici, Marco; van Ham, Willy; Vermeij, Wilbert P; de Waard, Monique C; de Krijger, Ronald R; Boelen, Anita; Kwakkel, Joan; Kopchick, John J; List, Edward O; Melis, Joost P M; Darras, Veerle M; Dollé, Martijn E T; van der Horst, Gijsbertus T J; Hoeijmakers, Jan H J; Visser, Theo J

    2016-01-01

    DNA damage contributes to the process of aging, as underscored by premature aging syndromes caused by defective DNA repair. Thyroid state changes during aging, but underlying mechanisms remain elusive. Since thyroid hormone (TH) is a key regulator of metabolism, changes in TH signaling have widespread effects. Here, we reveal a significant common transcriptomic signature in livers from hypothyroid mice, DNA repair-deficient mice with severe (Csbm/m/Xpa-/-) or intermediate (Ercc1-/Δ-7) progeria and naturally aged mice. A strong induction of TH-inactivating deiodinase D3 and decrease of TH-activating D1 activities are observed in Csbm/m/Xpa-/- livers. Similar findings are noticed in Ercc1-/Δ-7, in naturally aged animals and in wild-type mice exposed to a chronic subtoxic dose of DNA-damaging agents. In contrast, TH signaling in muscle, heart and brain appears unaltered. These data show a strong suppression of TH signaling in specific peripheral organs in premature and normal aging, probably lowering metabolism, while other tissues appear to preserve metabolism. D3-mediated TH inactivation is unexpected, given its expression mainly in fetal tissues. Our studies highlight the importance of DNA damage as the underlying mechanism of changes in thyroid state. Tissue-specific regulation of deiodinase activities, ensuring diminished TH signaling, may contribute importantly to the protective metabolic response in aging.

  8. Tissue-Specific Suppression of Thyroid Hormone Signaling in Various Mouse Models of Aging

    PubMed Central

    Visser, W. Edward; Barnhoorn, Sander; Ottaviani, Alexandre; van der Pluijm, Ingrid; Brandt, Renata; Kaptein, Ellen; van Heerebeek, Ramona; van Toor, Hans; Garinis, George A.; Peeters, Robin P.; Medici, Marco; van Ham, Willy; Vermeij, Wilbert P.; de Waard, Monique C.; de Krijger, Ronald R.; Boelen, Anita; Kwakkel, Joan; Kopchick, John J.; List, Edward O.; Melis, Joost P. M.; Darras, Veerle M.; Dollé, Martijn E. T.; van der Horst, Gijsbertus T. J.; Hoeijmakers, Jan H. J.; Visser, Theo J.

    2016-01-01

    DNA damage contributes to the process of aging, as underscored by premature aging syndromes caused by defective DNA repair. Thyroid state changes during aging, but underlying mechanisms remain elusive. Since thyroid hormone (TH) is a key regulator of metabolism, changes in TH signaling have widespread effects. Here, we reveal a significant common transcriptomic signature in livers from hypothyroid mice, DNA repair-deficient mice with severe (Csbm/m/Xpa-/-) or intermediate (Ercc1-/Δ-7) progeria and naturally aged mice. A strong induction of TH-inactivating deiodinase D3 and decrease of TH-activating D1 activities are observed in Csbm/m/Xpa-/- livers. Similar findings are noticed in Ercc1-/Δ-7, in naturally aged animals and in wild-type mice exposed to a chronic subtoxic dose of DNA-damaging agents. In contrast, TH signaling in muscle, heart and brain appears unaltered. These data show a strong suppression of TH signaling in specific peripheral organs in premature and normal aging, probably lowering metabolism, while other tissues appear to preserve metabolism. D3-mediated TH inactivation is unexpected, given its expression mainly in fetal tissues. Our studies highlight the importance of DNA damage as the underlying mechanism of changes in thyroid state. Tissue-specific regulation of deiodinase activities, ensuring diminished TH signaling, may contribute importantly to the protective metabolic response in aging. PMID:26953569

  9. Contribution of Physical Interactions to Signaling Specificity between a Diguanylate Cyclase and Its Effector

    PubMed Central

    Dahlstrom, Kurt M.; Giglio, Krista M.; Collins, Alan J.; Sondermann, Holger

    2015-01-01

    ABSTRACT Cyclic diguanylate (c-di-GMP) is a bacterial second messenger that controls multiple cellular processes. c-di-GMP networks have up to dozens of diguanylate cyclases (DGCs) that synthesize c-di-GMP along with many c-di-GMP-responsive target proteins that can bind and respond to this signal. For such networks to have order, a mechanism(s) likely exists that allow DGCs to specifically signal their targets, and it has been suggested that physical interactions might provide such specificity. Our results show a DGC from Pseudomonas fluorescens physically interacting with its target protein at a conserved interface, and this interface can be predictive of DGC-target protein interactions. Furthermore, we demonstrate that physical interaction is necessary for the DGC to maximally signal its target. If such “local signaling” is a theme for even a fraction of the DGCs used by bacteria, it becomes possible to posit a model whereby physical interaction allows a DGC to directly signal its target protein, which in turn may help curtail undesired cross talk with other members of the network. PMID:26670387

  10. Identification of specific gravity sensitive signal transduction pathways in human A431 carcinoma cells

    NASA Astrophysics Data System (ADS)

    Rijken, P. J.; de Groot, R. P.; Kruijer, W.; de Laat, S. W.; Verkleij, A. J.; Boonstra, J.

    Epidermal growth factor (EGF) activates a well characterized signal transduction cascade in human A431 epidermoid carcinoma cells. The influence of gravity on EGF-induced EGF-receptor clustering and early gene expression as well as on actin polymerization and actin organization have been investigated. Different signalling pathways induced by the agents TPA, forskolin and A23187 that activate gene expression were tested for sensitivity to gravity. EGF-induced c-fos and c-jun expression were decreased in microgravity. However, constitutive β-2 microglobulin expression remained unaltered. Under simulated weightlessness conditions EGF- and TPA-induced c-fos expression was decreased, while forskolin- and A23187-induced c-fos expression was independent of the gravity conditions. These results suggest that gravity affects specific signalling pathways. Preliminary results indicate that EGF-induced EGF-receptor clustering remained unaltered irrespective of the gravity conditions. Furthermore, the relative filamentous actin content of steady state A431 cells was enhanced under microgravity conditions and actin filament organization was altered. Under simulated weightlessness actin filament organization in steady state cells as well as in EGF-treated cells was altered as compared to the 1 G reference experiment. Interestingly the microtubule and keratin organization in untreated cells showed no difference with the normal gravity samples. This indicates that gravity may affect specific components of the signal transduction circuitry.

  11. Sex specific retinoic acid signaling is required for the initiation of urogenital sinus bud development.

    PubMed

    Bryant, Sarah L; Francis, Jeffrey C; Lokody, Isabel B; Wang, Hong; Risbridger, Gail P; Loveland, Kate L; Swain, Amanda

    2014-11-15

    The mammalian urogenital sinus (UGS) develops in a sex specific manner, giving rise to the prostate in the male and the sinus vagina in the embryonic female. Androgens, produced by the embryonic testis, have been shown to be crucial to this process. In this study we show that retinoic acid signaling is required for the initial stages of bud development from the male UGS. Enzymes involved in retinoic acid synthesis are expressed in the UGS mesenchyme in a sex specific manner and addition of ligand to female tissue is able to induce prostate-like bud formation in the absence of androgens, albeit at reduced potency. Functional studies in mouse organ cultures that faithfully reproduce the initiation of prostate development indicate that one of the roles of retinoic acid signaling in the male is to inhibit the expression of Inhba, which encodes the βA subunit of Activin, in the UGS mesenchyme. Through in vivo genetic analysis and culture studies we show that inhibition of Activin signaling in the female UGS leads to a similar phenotype to that of retinoic acid treatment, namely bud formation in the absence of androgens. Our data also reveals that both androgens and retinoic acid have extra independent roles to that of repressing Activin signaling in the development of the prostate during fetal stages. This study identifies a novel role for retinoic acid as a mesenchymal factor that acts together with androgens to determine the position and initiation of bud development in the male UGS epithelia. PMID:25261715

  12. Program-specific distribution of a transcription factor dependent on partner transcription factor and MAPK signaling.

    PubMed

    Zeitlinger, Julia; Simon, Itamar; Harbison, Christopher T; Hannett, Nancy M; Volkert, Thomas L; Fink, Gerald R; Young, Richard A

    2003-05-01

    Specialized gene expression programs are induced by signaling pathways that act on transcription factors. Whether these transcription factors can function in multiple developmental programs through a global switch in promoter selection is not known. We have used genome-wide location analysis to show that the yeast Ste12 transcription factor, which regulates mating and filamentous growth, is bound to distinct program-specific target genes dependent on the developmental condition. This condition-dependent distribution of Ste12 requires concurrent binding of the transcription factor Tec1 during filamentation and is differentially regulated by the MAP kinases Fus3 and Kss1. Program-specific distribution across the genome may be a general mechanism by which transcription factors regulate distinct gene expression programs in response to signaling. PMID:12732146

  13. A cortical vascular model for examining the specificity of the laminar BOLD signal.

    PubMed

    Markuerkiaga, Irati; Barth, Markus; Norris, David G

    2016-05-15

    Blood oxygenation level dependent (BOLD) functional MRI has been used for inferring layer specific activation in humans. However, intracortical veins perpendicular to the cortical surface are suspected to degrade the laminar specificity as they drain blood from the microvasculature and BOLD signal is carried over from lower to upper cortical layers on its way to the pial surface. In this work, a vascular model of the cortex is developed to investigate the laminar specificity of the BOLD signal for Spin Echo (SE) and Gradient Echo (GE) following the integrative model presented by Uludağ et al. (2009). The results of the simulation show that the laminar point spread function (PSF) of the BOLD signal presents similar features across all layers. The PSF for SE is highly localised whereas for GE there is a flat tail running to the pial surface, with amplitude less than a quarter of the response from the layer itself. Consequently the GE response at any layer will also contain a contribution accumulated from all lower layers. PMID:26952195

  14. A cortical vascular model for examining the specificity of the laminar BOLD signal.

    PubMed

    Markuerkiaga, Irati; Barth, Markus; Norris, David G

    2016-05-15

    Blood oxygenation level dependent (BOLD) functional MRI has been used for inferring layer specific activation in humans. However, intracortical veins perpendicular to the cortical surface are suspected to degrade the laminar specificity as they drain blood from the microvasculature and BOLD signal is carried over from lower to upper cortical layers on its way to the pial surface. In this work, a vascular model of the cortex is developed to investigate the laminar specificity of the BOLD signal for Spin Echo (SE) and Gradient Echo (GE) following the integrative model presented by Uludağ et al. (2009). The results of the simulation show that the laminar point spread function (PSF) of the BOLD signal presents similar features across all layers. The PSF for SE is highly localised whereas for GE there is a flat tail running to the pial surface, with amplitude less than a quarter of the response from the layer itself. Consequently the GE response at any layer will also contain a contribution accumulated from all lower layers.

  15. Developmental stage-specific interplay of GATA1 and IGF signaling in fetal megakaryopoiesis and leukemogenesis

    PubMed Central

    Klusmann, Jan-Henning; Godinho, Frank J.; Heitmann, Kirsten; Maroz, Aliaksandra; Lee Koch, Mia; Reinhardt, Dirk; Orkin, Stuart H.; Li, Zhe

    2010-01-01

    Oncogene-mediated transformation of hematopoietic cells has been studied extensively, but little is known about the molecular basis for restriction of oncogenes to certain target cells and differential cellular context-specific requirements for oncogenic transformation between infant and adult leukemias. Understanding cell type-specific interplay of signaling pathways and oncogenes is essential for developing targeted cancer therapies. Here, we address the vexing issue of how developmental restriction is achieved in Down syndrome acute megakaryoblastic leukemia (DS-AMKL), characterized by the triad of fetal origin, mutated GATA1 (GATA1s), and trisomy 21. We demonstrate overactivity of insulin-like growth factor (IGF) signaling in authentic human DS-AMKL and in a DS-AMKL mouse model generated through retroviral insertional mutagenesis. Fetal but not adult megakaryocytic progenitors are dependent on this pathway. GATA1 restricts IGF-mediated activation of the E2F transcription network to coordinate proliferation and differentiation. Failure of a direct GATA1–E2F interaction in mutated GATA1s converges with overactive IGF signaling to promote cellular transformation of DS fetal progenitors, revealing a complex, fetal stage-specific regulatory network. Our study underscores context-dependent requirements during oncogenesis, and explains resistance to transformation of ostensibly similar adult progenitors. PMID:20679399

  16. OTULIN Antagonizes LUBAC Signaling by Specifically Hydrolyzing Met1-Linked Polyubiquitin

    PubMed Central

    Keusekotten, Kirstin; Elliott, Paul Ronald; Glockner, Laura; Fiil, Berthe Katrine; Damgaard, Rune Busk; Kulathu, Yogesh; Wauer, Tobias; Hospenthal, Manuela Kathrin; Gyrd-Hansen, Mads; Krappmann, Daniel; Hofmann, Kay; Komander, David

    2013-01-01

    Summary The linear ubiquitin (Ub) chain assembly complex (LUBAC) is an E3 ligase that specifically assembles Met1-linked (also known as linear) Ub chains that regulate nuclear factor κB (NF-κB) signaling. Deubiquitinases (DUBs) are key regulators of Ub signaling, but a dedicated DUB for Met1 linkages has not been identified. Here, we reveal a previously unannotated human DUB, OTULIN (also known as FAM105B), which is exquisitely specific for Met1 linkages. Crystal structures of the OTULIN catalytic domain in complex with diubiquitin reveal Met1-specific Ub-binding sites and a mechanism of substrate-assisted catalysis in which the proximal Ub activates the catalytic triad of the protease. Mutation of Ub Glu16 inhibits OTULIN activity by reducing kcat 240-fold. OTULIN overexpression or knockdown affects NF-κB responses to LUBAC, TNFα, and poly(I:C) and sensitizes cells to TNFα-induced cell death. We show that OTULIN binds LUBAC and that overexpression of OTULIN prevents TNFα-induced NEMO association with ubiquitinated RIPK1. Our data suggest that OTULIN regulates Met1-polyUb signaling. PMID:23746843

  17. Human-Specific Genes May Offer a Unique Window into Human Cell Signaling

    PubMed Central

    Stahl, Philip D.; Wainszelbaum, Marisa J.

    2013-01-01

    The identification and characterization of human-specific genes and the cellular processes that the encoded proteins control have the potential to help us understand at the molecular level what makes humans different from other species. The sequencing of the human genome and the genomes of closely related primates has revealed the presence of a small number of human- or human-lineage–specific genes that have no orthologs in lower species. Human-specific and human-lineage–specific genes are likely to function as regulators of cell signaling events, and by fine-tuning pathways, the encoded proteins may contribute to human-specific characteristics and behaviors. In addition, human-specific genes may represent biomarkers for examining human-specific characteristics of various diseases. Investigation of the gene encoding TBC1D3 is one example of a search that may lead to understanding the evolution and the function of human-specific genes, because it is absent in lower species and present in high copy number in the human genome. PMID:19797272

  18. UV-radiation-induced electron emission by hormones. Hypothesis for specific communication mechanisms

    NASA Astrophysics Data System (ADS)

    Getoff, Nikola

    2009-11-01

    The highlights of recently observed electron emission from electronically excited sexual hormones (17β-estradiol, progesterone, testosterone) and the phytohormone genistein in polar media are briefly reviewed. The electron yield, Q(e aq-), dependence from substrate concentration, hormone structure, polarity of solvent, absorbed energy and temperature are discussed. The hormones reactivity with e aq- and efficiency in electron transfer ensure them the ability to communicate with other biological systems in an organism. A hypothesis is presented for the explanation of the mechanisms of the distinct recognition of signals transmitted by electrons, originating from different types of hormones to receiving centres. Biological consequences of the electron emission in respect to cancer are mentioned.

  19. Cell-type-specific modelling of intracellular calcium signalling: a urothelial cell model.

    PubMed

    Appleby, Peter A; Shabir, Saqib; Southgate, Jennifer; Walker, Dawn

    2013-09-01

    Calcium signalling plays a central role in regulating a wide variety of cell processes. A number of calcium signalling models exist in the literature that are capable of reproducing a variety of experimentally observed calcium transients. These models have been used to examine in more detail the mechanisms underlying calcium transients, but very rarely has a model been directly linked to a particular cell type and experimentally verified. It is important to show that this can be achieved within the general theoretical framework adopted by these models. Here, we develop a framework designed specifically for modelling cytosolic calcium transients in urothelial cells. Where possible, we draw upon existing calcium signalling models, integrating descriptions of components known to be important in this cell type from a number of studies in the literature. We then add descriptions of several additional pathways that play a specific role in urothelial cell signalling, including an explicit ionic influx term and an active pumping mechanism that drives the cytosolic calcium concentration to a target equilibrium. The resulting one-pool model of endoplasmic reticulum (ER)-dependent calcium signalling relates the cytosolic, extracellular and ER calcium concentrations and can generate a wide range of calcium transients, including spikes, bursts, oscillations and sustained elevations in the cytosolic calcium concentration. Using single-variate robustness and multivariate sensitivity analyses, we quantify how varying each of the parameters of the model leads to changes in key features of the calcium transient, such as initial peak amplitude and the frequency of bursting or spiking, and in the transitions between bursting- and plateau-dominated modes. We also show that, novel to our urothelial cell model, the ionic and purinergic P2Y pathways make distinct contributions to the calcium transient. We then validate the model using human bladder epithelial cells grown in monolayer cell

  20. [A modified speech enhancement algorithm for electronic cochlear implant and its digital signal processing realization].

    PubMed

    Wang, Yulin; Tian, Xuelong

    2014-08-01

    In order to improve the speech quality and auditory perceptiveness of electronic cochlear implant under strong noise background, a speech enhancement system used for electronic cochlear implant front-end was constructed. Taking digital signal processing (DSP) as the core, the system combines its multi-channel buffered serial port (McBSP) data transmission channel with extended audio interface chip TLV320AIC10, so speech signal acquisition and output with high speed are realized. Meanwhile, due to the traditional speech enhancement method which has the problems as bad adaptability, slow convergence speed and big steady-state error, versiera function and de-correlation principle were used to improve the existing adaptive filtering algorithm, which effectively enhanced the quality of voice communications. Test results verified the stability of the system and the de-noising performance of the algorithm, and it also proved that they could provide clearer speech signals for the deaf or tinnitus patients.

  1. [A modified speech enhancement algorithm for electronic cochlear implant and its digital signal processing realization].

    PubMed

    Wang, Yulin; Tian, Xuelong

    2014-08-01

    In order to improve the speech quality and auditory perceptiveness of electronic cochlear implant under strong noise background, a speech enhancement system used for electronic cochlear implant front-end was constructed. Taking digital signal processing (DSP) as the core, the system combines its multi-channel buffered serial port (McBSP) data transmission channel with extended audio interface chip TLV320AIC10, so speech signal acquisition and output with high speed are realized. Meanwhile, due to the traditional speech enhancement method which has the problems as bad adaptability, slow convergence speed and big steady-state error, versiera function and de-correlation principle were used to improve the existing adaptive filtering algorithm, which effectively enhanced the quality of voice communications. Test results verified the stability of the system and the de-noising performance of the algorithm, and it also proved that they could provide clearer speech signals for the deaf or tinnitus patients. PMID:25464779

  2. [A modified speech enhancement algorithm for electronic cochlear implant and its digital signal processing realization].

    PubMed

    Wang, Yulin; Tian, Xuelong

    2014-08-01

    In order to improve the speech quality and auditory perceptiveness of electronic cochlear implant under strong noise background, a speech enhancement system used for electronic cochlear implant front-end was constructed. Taking digital signal processing (DSP) as the core, the system combines its multi-channel buffered serial port (McBSP) data transmission channel with extended audio interface chip TLV320AIC10, so speech signal acquisition and output with high speed are realized. Meanwhile, due to the traditional speech enhancement method which has the problems as bad adaptability, slow convergence speed and big steady-state error, versiera function and de-correlation principle were used to improve the existing adaptive filtering algorithm, which effectively enhanced the quality of voice communications. Test results verified the stability of the system and the de-noising performance of the algorithm, and it also proved that they could provide clearer speech signals for the deaf or tinnitus patients. PMID:25508410

  3. Generation of THz signals based on quasi-ballistic electron reflections in double-heterojunction structures

    NASA Astrophysics Data System (ADS)

    Ong, D. S.; Hartnagel, H. L.

    2007-09-01

    The generation of THz signals by the periodic quasi-ballistic resonant motion of electrons on the basis of the combined action of electron acceleration in a potential well and reflection at the heterointerface is demonstrated by a Monte Carlo simulation. The electron dynamics in In0.52Al0.48As/In0.53Ga0.47As/In0.52Al0.48As heterostructures is investigated for different well widths and doping densities under the influence of fundamental-wave signals which conveniently can also be of square shape of 100 GHz and 200 GHz. It is found that the resulting quasi-ballistic electron motion produces oscillations within these wells which generate particularly high odd harmonics in the terahertz frequency range. Simulation results of this new type of resonance phenomenon show that the amplitude of the THz radiation strongly depends on the well width and voltage level of the square wave signal. This study shows that double-heterojunction structures with well width of ballistic electron transport length are promising candidates for the design of efficient THz sources.

  4. Mapping the intramolecular contributions to the inelastic electron tunneling signal of a molecular junction

    NASA Astrophysics Data System (ADS)

    Foti, Giuseppe; Vázquez, Héctor

    2016-07-01

    We present a quantitative analysis of the intramolecular origin of the inelastic electron tunneling signal of a molecular junction. We use density-functional theory to study a representative conjugated molecule with a low degree of symmetry and calculate, for all modes, the different contributions that give rise to the vibrational spectrum. These local contributions involve products of scattering states with electron-phonon matrix elements and thus encode information on both the vibrational modes and the electronic structure. We separate these intra- and interatomic terms and draw a pattern of addition or cancellation of these partial contributions throughout the inelastic spectrum. This allows for a quantitative relation between the degree of symmetry of each vibrational mode, its inelastic signal, and the locality of selection rules.

  5. 36 CFR 1235.50 - What specifications and standards for transfer apply to electronic records?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... electronic records in a format that is independent of specific hardware or software. Except as specified in... indicators for variable length records, or marks delimiting a data element, field, record, or file....

  6. 36 CFR 1235.50 - What specifications and standards for transfer apply to electronic records?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... electronic records in a format that is independent of specific hardware or software. Except as specified in... indicators for variable length records, or marks delimiting a data element, field, record, or file....

  7. 36 CFR 1235.50 - What specifications and standards for transfer apply to electronic records?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... electronic records in a format that is independent of specific hardware or software. Except as specified in... indicators for variable length records, or marks delimiting a data element, field, record, or file....

  8. The Legalities and Practicalities of Developing a Course-Specific Electronic Reserve Room.

    ERIC Educational Resources Information Center

    Curran, Mary A.; Curran, Kent E.

    2002-01-01

    Advocates a course-specific electronic reserve for timely, simplified distribution of course readings. Provides guidelines for the copyright and fair use implications of electronic reserve, suggesting a password-protected site. Explains the logistics of file creation, software, and hardware. (Contains 14 references.) (SK)

  9. GDE2 regulates subtype-specific motor neuron generation through inhibition of Notch signaling.

    PubMed

    Sabharwal, Priyanka; Lee, Changhee; Park, Sungjin; Rao, Meenakshi; Sockanathan, Shanthini

    2011-09-22

    The specification of spinal interneuron and motor neuron identities initiates within progenitor cells, while motor neuron subtype diversification is regulated by hierarchical transcriptional programs implemented postmitotically. Here we find that mice lacking GDE2, a six-transmembrane protein that triggers motor neuron generation, exhibit selective losses of distinct motor neuron subtypes, specifically in defined subsets of limb-innervating motor pools that correlate with the loss of force-generating alpha motor neurons. Mechanistically, GDE2 is expressed by postmitotic motor neurons but utilizes extracellular glycerophosphodiester phosphodiesterase activity to induce motor neuron generation by inhibiting Notch signaling in neighboring motor neuron progenitors. Thus, neuronal GDE2 controls motor neuron subtype diversity through a non-cell-autonomous feedback mechanism that directly regulates progenitor cell differentiation, implying that subtype specification initiates within motor neuron progenitor populations prior to their differentiation into postmitotic motor neurons.

  10. Region-specific regulation of cell proliferation by FGF receptor signaling during the Wolffian duct development

    PubMed Central

    Okazawa, Mika; Murashima, Aki; Harada, Masayo; Nakagata, Naomi; Noguchi, Masafumi; Morimoto, Mitsuru; Kimura, Tadashi; Ornitz, David M.; Yamada, Gen

    2015-01-01

    The Wolffian duct (WD) is a primordium of the male reproductive tract and kidney collecting duct system. Fibroblast growth factor receptors (FGFRs), members of the receptor tyrosine kinase (RTK) family, are essential for kidney development. Although the functions of FGFR signaling in kidney morphogenesis have been analyzed, their function in WD development has not been comprehensively investigated. Here, we demonstrate that Fgfr2 is the major Fgfr gene expressed throughout the WD epithelia and that it is essential for the maintenance of the WD, specifically in the caudal part of the WD. Hoxb7-Cre mediated inactivation of Fgfr2 in the mouse WD epithelia resulted in the regression of the caudal part of the WD and abnormal male reproductive tract development. Cell proliferation and expression of the downstream target genes of RTK signaling (Etv4 and Etv5) were decreased in the caudal part of the WD epithelia in the mutant embryos. Cranial (rostral) WD formation and ureteric budding were not affected. Ret, Etv4, and Etv5 expression were sustained in the ureteric bud of the mutant embryos. Taken together, these data suggest region-specific requirements for FGFR2 signaling in the developing caudal WD epithelia. PMID:25678108

  11. Decoding Finger Flexion from Band-Specific ECoG Signals in Humans

    PubMed Central

    Liang, Nanying; Bougrain, Laurent

    2012-01-01

    This article presents the method that won the brain-computer interface (BCI) competition IV addressed to the prediction of the finger flexion from electrocorticogram (ECoG) signals. ECoG-based BCIs have recently drawn the attention from the community. Indeed, ECoG can provide higher spatial resolution and better signal quality than classical EEG recordings. It is also more suitable for long-term use. These characteristics allow to decode precise brain activities and to realize efficient ECoG-based neuroprostheses. Signal processing is a very important task in BCIs research for translating brain signals into commands. Here, we present a linear regression method based on the amplitude modulation of band-specific ECoG including a short-term memory for individual finger flexion prediction. The effectiveness of the method was proven by achieving the highest value of correlation coefficient between the predicted and recorded finger flexion values on data set 4 during the BCI competition IV. PMID:22754496

  12. Perturbations of subionospheric LF and MF signals due to whistler-induced electron precipitation bursts

    NASA Technical Reports Server (NTRS)

    Carpenter, D. L.; Inan, U. S.; Trimpi, M. L.; Helliwell, R. A.; Katsufrakis, J. P.

    1984-01-01

    Increasing attention is now being devoted to the problem of the pitch angle scattering and resulting precipitation of magnetospheric energetic electrons by coherent waves. The present investigation has the objective to report the first evidence of a correlation between whistlers and amplitude perturbations on low-frequency (LF) signals at 37.2 kHz and medium-frequency (MF) signals at 780 kHz. Whistler-correlated amplitude perturbations were observed on a 780-kHz MF signal propagating on an approximately 1800 km path from South America to Palmer. The observed MF perturbations were of order 50 percent in amplitude and developed much more quickly than other changes of comparable magnitude on the signal.

  13. Signal processing and display interface studies. [performance tests - design analysis/equipment specifications

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Signal processing equipment specifications, operating and test procedures, and systems design and engineering are described. Five subdivisions of the overall circuitry are treated: (1) the spectrum analyzer; (2) the spectrum integrator; (3) the velocity discriminator; (4) the display interface; and (5) the formatter. They function in series: (1) first in analog form to provide frequency resolution, (2) then in digital form to achieve signal to noise improvement (video integration) and frequency discrimination, and (3) finally in analog form again for the purpose of real-time display of the significant velocity data. The formatter collects binary data from various points in the processor and provides a serial output for bi-phase recording. Block diagrams are used to illustrate the system.

  14. EGF receptor specificity for phosphotyrosine-primed substrates provides signal integration with Src

    PubMed Central

    Begley, Michael J; Yun, Cai-hong; Gewinner, Christina A; Asara, John M; Johnson, Jared L; Coyle, Anthony J; Eck, Michael J; Apostolou, Irina; Cantley, Lewis C

    2016-01-01

    Aberrant activation of the EGF receptor (EGFR) contributes to many human cancers by activating the Ras-MAPK and other pathways. EGFR signaling is augmented by Src-family kinases, but the mechanism is poorly understood. Here, we show that human EGFR preferentially phosphorylates peptide substrates that are primed by a prior phosphorylation. Utilizing peptides based on the sequence of the adaptor protein Shc1, we show that Src mediates the priming phosphorylation, promoting subsequent phosphorylation by EGFR. Importantly, the doubly phosphorylated Shc1 peptide binds more tightly to the Ras activator Grb2, a key step in activating the Ras-MAPK pathway, than singly phosphorylated peptides. Finally, a crystal structure of EGFR in complex with a primed Shc1 peptide reveals the structural basis for EGFR substrate specificity. These results provide a molecular explanation for the integration of Src and EGFR signaling with downstream effectors such as Ras. PMID:26551075

  15. Structural insight into partner specificity and phosphoryl transfer in two-component signal transduction.

    PubMed

    Casino, Patricia; Rubio, Vicente; Marina, Alberto

    2009-10-16

    The chief mechanism used by bacteria for sensing their environment is based on two conserved proteins: a sensor histidine kinase (HK) and an effector response regulator (RR). The signal transduction process involves highly conserved domains of both proteins that mediate autokinase, phosphotransfer, and phosphatase activities whose output is a finely tuned RR phosphorylation level. Here, we report the structure of the complex between the entire cytoplasmic portion of Thermotoga maritima class I HK853 and its cognate, RR468, as well as the structure of the isolated RR468, both free and BeF(3)(-) bound. Our results provide insight into partner specificity in two-component systems, recognition of the phosphorylation state of each partner, and the catalytic mechanism of the phosphatase reaction. Biochemical analysis shows that the HK853-catalyzed autokinase reaction proceeds by a cis autophosphorylation mechanism within the HK subunit. The results suggest a model for the signal transduction mechanism in two-component systems.

  16. Epithelial-Specific Requirement of FGFR2 Signaling During Tooth and Palate Development

    PubMed Central

    HOSOKAWA, RYOICHI; DENG, XUEMEI; TAKAMORI, KAZUNORI; XU, XUN; URATA, MARK; BRINGAS, PABLO; CHAI, YANG

    2010-01-01

    Reciprocal interactions between epithelium and mesenchyme are crucial for embryonic development. Fibroblast growth factors (FGFs) are a growth factor family that play an important role in epithelial–mesenchymal tissue interaction. We have generated epithelial-specific conditional knockout mice targeting Fibroblast growth factor receptor 2 (Fgfr2) to investigate the function of FGF signaling during craniofacial development. K14-Cre;Fgfr2fl/fl mice have skin defects, retarded tooth formation, and cleft palate. During the formation of the tooth primordium and palatal processes, cell proliferation in the epithelial cells of K14-Cre;Fgfr2fl/fl mice is reduced. Thus, FGF signaling via FGFR2 in the epithelium is crucial for cell proliferation activity during tooth and palate development. PMID:19235875

  17. Design, development, and fabrication of a electronic analog microminiaturized electronic analog signal to discrete time interval converter

    NASA Technical Reports Server (NTRS)

    Schoenfeld, A. D.; Schuegraf, K. K.

    1973-01-01

    The microminiaturization of an electronic analog signal to discrete time interval converter is presented. Discrete components and integrated circuits comprising the converter were assembled on a thin-film ceramic substrate containing nichrome resistors with gold interconnections. The finished assembly is enclosed in a flat package measuring 3.30 by 4.57 centimeters. The module can be used whenever conversion of analog to digital signals is required, in particular for the purpose of regulation by means of pulse modulation. In conjunction with a precision voltage reference, the module was applied to control the duty cycle of a switching regulator within a temperature range of -55 C to +125 C, and an input voltage range of 10V to 35V. The output-voltage variation was less than + or - 300 parts per million, i.e., less than + or - 3mV for a 10V output.

  18. Interference in Ballistic Motor Learning: Specificity and Role of Sensory Error Signals

    PubMed Central

    Lundbye-Jensen, Jesper; Petersen, Tue Hvass; Rothwell, John C.; Nielsen, Jens Bo

    2011-01-01

    Humans are capable of learning numerous motor skills, but newly acquired skills may be abolished by subsequent learning. Here we ask what factors determine whether interference occurs in motor learning. We speculated that interference requires competing processes of synaptic plasticity in overlapping circuits and predicted specificity. To test this, subjects learned a ballistic motor task. Interference was observed following subsequent learning of an accuracy-tracking task, but only if the competing task involved the same muscles and movement direction. Interference was not observed from a non-learning task suggesting that interference requires competing learning. Subsequent learning of the competing task 4 h after initial learning did not cause interference suggesting disruption of early motor memory consolidation as one possible mechanism underlying interference. Repeated transcranial magnetic stimulation (rTMS) of corticospinal motor output at intensities below movement threshold did not cause interference, whereas suprathreshold rTMS evoking motor responses and (re)afferent activation did. Finally, the experiments revealed that suprathreshold repetitive electrical stimulation of the agonist (but not antagonist) peripheral nerve caused interference. The present study is, to our knowledge, the first to demonstrate that peripheral nerve stimulation may cause interference. The finding underscores the importance of sensory feedback as error signals in motor learning. We conclude that interference requires competing plasticity in overlapping circuits. Interference is remarkably specific for circuits involved in a specific movement and it may relate to sensory error signals. PMID:21408054

  19. Prolonged hyperinsulinemia affects metabolic signal transduction markers in a tissue specific manner.

    PubMed

    Campolo, A; de Laat, M A; Keith, L; Gruntmeir, K J; Lacombe, V A

    2016-04-01

    Insulin dysregulation is common in horses although the mechanisms of metabolic dysfunction are poorly understood. We hypothesized that insulin signaling in striated (cardiac and skeletal) muscle and lamellae may be mediated through different receptors as a result of receptor content, and that transcriptional regulation of downstream signal transduction and glucose transport may also differ between tissues sites during hyperinsulinemia. Archived samples from horses treated with a prolonged insulin infusion or a balanced electrolyte solution were used. All treated horses developed marked hyperinsulinemia and clinical laminitis. Protein expression was compared across tissues for the insulin receptor and insulin-like growth factor 1 receptor (IGF-1R) by immunoblotting. Gene expression of metabolic insulin-signaling markers (insulin receptor substrate 1, Akt2, and glycogen synthase kinase 3 beta [GSK-3β]) and glucose transport (basal glucose transporter 1 and insulin-sensitive glucose transporter 4) was evaluated using real-time reverse transcription polymerase chain reaction. Lamellar tissue contained significantly more IGF-1R protein than skeletal muscle, indicating the potential significance of IGF-1R signaling for this tissue. Gene expression of the selected markers of insulin signaling and glucose transport in skeletal muscle and lamellar tissues was unaffected by prolonged hyperinsulinemia. In contrast, the significant upregulation of Akt2, GSK-3β, GLUT1, and GLUT4 gene expression in cardiac tissue suggested that the prolonged hyperinsulinemia induced an increase in insulin sensitivity and a transcriptional activation of glucose transport. Responses to insulin are tissue-specific, and extrapolation of data across tissue sites is inappropriate. PMID:26773366

  20. Brain-specific Angiogenesis Inhibitor-1 Signaling, Regulation, and Enrichment in the Postsynaptic Density*

    PubMed Central

    Stephenson, Jason R.; Paavola, Kevin J.; Schaefer, Stacy A.; Kaur, Balveen; Van Meir, Erwin G.; Hall, Randy A.

    2013-01-01

    Brain-specific angiogenesis inhibitor-1 (BAI1) is an adhesion G protein-coupled receptor that has been studied primarily for its anti-angiogenic and anti-tumorigenic properties. We found that overexpression of BAI1 results in activation of the Rho pathway via a Gα12/13-dependent mechanism, with truncation of the BAI1 N terminus resulting in a dramatic enhancement in receptor signaling. This constitutive activity of the truncated BAI1 mutant also resulted in enhanced downstream phosphorylation of ERK as well as increased receptor association with β-arrestin2 and increased ubiquitination of the receptor. To gain insights into the regulation of BAI1 signaling, we screened the C terminus of BAI1 against a proteomic array of PDZ domains to identify novel interacting partners. These screens revealed that the BAI1 C terminus interacts with a variety of PDZ domains from synaptic proteins, including MAGI-3. Removal of the BAI1 PDZ-binding motif resulted in attenuation of receptor signaling to Rho but had no effect on ERK activation. Conversely, co-expression with MAGI-3 was found to potentiate signaling to ERK by constitutively active BAI1 in a manner that was dependent on the PDZ-binding motif of the receptor. Biochemical fractionation studies revealed that BAI1 is highly enriched in post-synaptic density fractions, a finding consistent with our observations that BAI1 can interact with PDZ proteins known to be concentrated in the post-synaptic density. These findings demonstrate that BAI1 is a synaptic receptor that can activate both the Rho and ERK pathways, with the N-terminal and C-terminal regions of the receptor playing key roles in the regulation of BAI1 signaling activity. PMID:23782696

  1. A UV-B-specific signaling component orchestrates plant UV protection.

    PubMed

    Brown, Bobby A; Cloix, Catherine; Jiang, Guang Huai; Kaiserli, Eirini; Herzyk, Pawel; Kliebenstein, Daniel J; Jenkins, Gareth I

    2005-12-13

    UV-B radiation in sunlight has diverse effects on humans, animals, plants, and microorganisms. UV-B can cause damage to molecules and cells, and consequently organisms need to protect against and repair UV damage to survive in sunlight. In plants, low nondamaging levels of UV-B stimulate transcription of genes involved in UV-protective responses. However, remarkably little is known about the underlying mechanisms of UV-B perception and signal transduction. Here we report that Arabidopsis UV RESISTANCE LOCUS 8 (UVR8) is a UV-B-specific signaling component that orchestrates expression of a range of genes with vital UV-protective functions. Moreover, we show that UVR8 regulates expression of the transcription factor HY5 specifically when the plant is exposed to UV-B. We demonstrate that HY5 is a key effector of the UVR8 pathway, and that it is required for survival under UV-B radiation. UVR8 has sequence similarity to the eukaryotic guanine nucleotide exchange factor RCC1, but we found that it has little exchange activity. However, UVR8, like RCC1, is located principally in the nucleus and associates with chromatin via histones. Chromatin immunoprecipitation showed that UVR8 associates with chromatin in the HY5 promoter region, providing a mechanistic basis for its involvement in regulating transcription. We conclude that UVR8 defines a UV-B-specific signaling pathway in plants that orchestrates the protective gene expression responses to UV-B required for plant survival in sunlight.

  2. Subject specific BOLD fMRI respiratory and cardiac response functions obtained from global signal.

    PubMed

    Falahpour, Maryam; Refai, Hazem; Bodurka, Jerzy

    2013-05-15

    Subtle changes in either breathing pattern or cardiac pulse rate alter blood oxygen level dependent functional magnetic resonance imaging signal (BOLD fMRI). This is problematic because such fluctuations could possibly not be related to underlying neuronal activations of interest but instead the source of physiological noise. Several methods have been proposed to eliminate physiological noise in BOLD fMRI data. One such method is to derive a template based on average multi-subject data for respiratory response function (RRF) and cardiac response function (CRF) by simultaneously utilizing an external recording of cardiac and respiratory waveforms with the fMRI. Standard templates can then be used to model, map, and remove respiration and cardiac fluctuations from fMRI data. Utilizing these does not, however, account for intra-subject variations in physiological response. Thus, performing a more individualized approach for single subject physiological noise correction becomes more desirable, especially for clinical purposes. Here we propose a novel approach that employs subject-specific RRF and CRF response functions obtained from the whole brain or brain tissue-specific global signals (GS). Averaging multiple voxels in global signal computation ensures physiological noise dominance over thermal and system noise in even high-spatial-resolution fMRI data, making the GS suitable for deriving robust estimations of both RRF and CRF for individual subjects. Using these individualized response functions instead of standard templates based on multi-subject averages judiciously removes physiological noise from the data, assuming that there is minimal neuronal contribution in the derived individualized filters. Subject-specific physiological response functions obtained from the GS better maps individuals' physiological characteristics.

  3. Analysis of Technical Specifications of the Egyptian and French Electronic Storybooks (e-Storybook)

    ERIC Educational Resources Information Center

    Atta, Mohammed Mahmoud; Abd El Wahab, Shaimaa Mahmoud

    2015-01-01

    This research aims at analysing technical specifications in a sample of Egyptian and French electronic storybooks (e-storybooks), to identify similarities and differences in technical specifications of children's e-storybooks and create a verified analysis list to be used for evaluation of e-storybooks. For this purpose, 32 e-storybooks in CD…

  4. The influence of the electronic specific heat on swift heavy ion irradiation simulations of silicon.

    PubMed

    Khara, Galvin S; Murphy, Samuel T; Daraszewicz, Szymon L; Duffy, Dorothy M

    2016-10-01

    The swift heavy ion (SHI) irradiation of materials is often modelled using the two-temperature model. While the model has been successful in describing SHI damage in metals, it fails to account for the presence of a bandgap in semiconductors and insulators. Here we explore the potential to overcome this limitation by explicitly incorporating the influence of the bandgap in the parameterisation of the electronic specific heat for Si. The specific heat as a function of electronic temperature is calculated using finite temperature density functional theory with three different exchange correlation functionals, each with a characteristic bandgap. These electronic temperature dependent specific heats are employed with two-temperature molecular dynamics to model ion track creation in Si. The results obtained using a specific heat derived from density functional theory showed dramatically reduced defect creation compared to models that used the free electron gas specific heat. As a consequence, the track radii are smaller and in much better agreement with experimental observations. We also observe a correlation between the width of the band gap and the track radius, arising due to the variation in the temperature dependence of the electronic specific heat. PMID:27501917

  5. The influence of the electronic specific heat on swift heavy ion irradiation simulations of silicon.

    PubMed

    Khara, Galvin S; Murphy, Samuel T; Daraszewicz, Szymon L; Duffy, Dorothy M

    2016-10-01

    The swift heavy ion (SHI) irradiation of materials is often modelled using the two-temperature model. While the model has been successful in describing SHI damage in metals, it fails to account for the presence of a bandgap in semiconductors and insulators. Here we explore the potential to overcome this limitation by explicitly incorporating the influence of the bandgap in the parameterisation of the electronic specific heat for Si. The specific heat as a function of electronic temperature is calculated using finite temperature density functional theory with three different exchange correlation functionals, each with a characteristic bandgap. These electronic temperature dependent specific heats are employed with two-temperature molecular dynamics to model ion track creation in Si. The results obtained using a specific heat derived from density functional theory showed dramatically reduced defect creation compared to models that used the free electron gas specific heat. As a consequence, the track radii are smaller and in much better agreement with experimental observations. We also observe a correlation between the width of the band gap and the track radius, arising due to the variation in the temperature dependence of the electronic specific heat.

  6. Examining the specific entropy (density of adiabatic invariants) of the outer electron radiation belt

    SciTech Connect

    Borovsky, Joseph E; Denton, Michael H

    2008-01-01

    Using temperature and number-density measurements of the energetic-electron population from multiple spacecraft in geosynchronous orbit, the specific entropy S = T/n{sup 2/3} of the outer electron radiation belt is calculated. Then 955,527 half-hour-long data intervals are statistically analyzed. Local-time and solar-cycle variations in S are examined. The median value of the specific entropy (2.8 x 10{sup 7} eVcm{sup 2}) is much larger than the specific entropy of other particle populations in and around the magnetosphere. The evolution of the specific entropy through high-speed-stream-driven geomagnetic storms and through magnetic-cloud-driven geomagnetic storms is studied using superposed-epoch analysis. For high-speed-stream-driven storms, systematic variations in the entropy associated with electron loss and gain and with radiation-belt heating are observed in the various storm phases. For magnetic-cloud-driven storms, multiple trigger choices for the data superpositions reveal the effects of interplanetary shock arrival, sheath driving, cloud driving, and recovery phase. The specific entropy S = T/n{sup 2/3} is algebraically expressed in terms of the first and second adiabatic invariants of the electrons: this allows a relativistic expression for S in terms of T and n to be derived. For the outer electron radiation belt at geosynchronous orbit, the relativistic corrections to the specific entropy expression are -15%.

  7. The influence of the electronic specific heat on swift heavy ion irradiation simulations of silicon

    NASA Astrophysics Data System (ADS)

    Khara, Galvin S.; Murphy, Samuel T.; Daraszewicz, Szymon L.; Duffy, Dorothy M.

    2016-10-01

    The swift heavy ion (SHI) irradiation of materials is often modelled using the two-temperature model. While the model has been successful in describing SHI damage in metals, it fails to account for the presence of a bandgap in semiconductors and insulators. Here we explore the potential to overcome this limitation by explicitly incorporating the influence of the bandgap in the parameterisation of the electronic specific heat for Si. The specific heat as a function of electronic temperature is calculated using finite temperature density functional theory with three different exchange correlation functionals, each with a characteristic bandgap. These electronic temperature dependent specific heats are employed with two-temperature molecular dynamics to model ion track creation in Si. The results obtained using a specific heat derived from density functional theory showed dramatically reduced defect creation compared to models that used the free electron gas specific heat. As a consequence, the track radii are smaller and in much better agreement with experimental observations. We also observe a correlation between the width of the band gap and the track radius, arising due to the variation in the temperature dependence of the electronic specific heat.

  8. Combing signals from spontaneous reports and electronic health records for detection of adverse drug reactions

    PubMed Central

    Harpaz, Rave; Vilar, Santiago; DuMouchel, William; Salmasian, Hojjat; Haerian, Krystl; Shah, Nigam H; Chase, Herbert S; Friedman, Carol

    2013-01-01

    Objective Data-mining algorithms that can produce accurate signals of potentially novel adverse drug reactions (ADRs) are a central component of pharmacovigilance. We propose a signal-detection strategy that combines the adverse event reporting system (AERS) of the Food and Drug Administration and electronic health records (EHRs) by requiring signaling in both sources. We claim that this approach leads to improved accuracy of signal detection when the goal is to produce a highly selective ranked set of candidate ADRs. Materials and methods Our investigation was based on over 4 million AERS reports and information extracted from 1.2 million EHR narratives. Well-established methodologies were used to generate signals from each source. The study focused on ADRs related to three high-profile serious adverse reactions. A reference standard of over 600 established and plausible ADRs was created and used to evaluate the proposed approach against a comparator. Results The combined signaling system achieved a statistically significant large improvement over AERS (baseline) in the precision of top ranked signals. The average improvement ranged from 31% to almost threefold for different evaluation categories. Using this system, we identified a new association between the agent, rasburicase, and the adverse event, acute pancreatitis, which was supported by clinical review. Conclusions The results provide promising initial evidence that combining AERS with EHRs via the framework of replicated signaling can improve the accuracy of signal detection for certain operating scenarios. The use of additional EHR data is required to further evaluate the capacity and limits of this system and to extend the generalizability of these results. PMID:23118093

  9. Photo-detachment signal analysis to accurately determine electronegativity, electron temperature, and charged species density

    NASA Astrophysics Data System (ADS)

    Oudini, N.; Sirse, N.; Taccogna, F.; Ellingboe, A. R.; Bendib, A.

    2016-09-01

    Laser pulse induced photo-detachment combined with Langmuir probing has been introduced to diagnose plasma electronegativity. This technique uses a laser pulse to convert negative ions into electron-atom pairs and tracks the change of electron saturation current by a Langmuir probe. The existing model determines plasma electronegativity as the ratio of electron saturation current before and after detachment. However, this model depends on various assumptions and neglects the formation of a potential barrier between the laser channel and surrounding electronegative plasma. In this letter, we present a new analytical model to analyze photo-detachment signals in order to improve the accuracy of electronegativity measurements and extend this technique for measuring electron temperature and charged species density. This analytical model is supported by Particle-In-Cell simulation of electronegative plasma dynamics following laser photo-detachment. The analysis of the signal, detected on a simulated probe, shows that the present analytical model determines electronegativity, electron temperature, and plasma density with a relative error of ˜20%, ˜20%, and ˜50%, respectively, whereas the electronegativity obtained from a previous model is underestimated by an order of magnitude.

  10. Dendritic cell specific targeting of MyD88 signalling pathways in vivo.

    PubMed

    Arnold-Schrauf, Catharina; Berod, Luciana; Sparwasser, Tim

    2015-01-01

    Dendritic cells (DCs) are key regulators of both innate and adaptive immunity. During infection, DCs recognise pathogen-associated molecular patterns (PAMPs) via pattern recognition receptors (PRRs) including the Toll-like receptor (TLR) family. TLRs mainly signal via the adaptor protein MyD88. This signalling pathway is required for immune protection during many infections, which are lethal in the absence of MyD88. However, the cell type specific importance of this pathway during both innate and adaptive immune responses against pathogens in vivo remains ill-defined. We discuss recent findings from conditional KO or gain-of-function mouse models targeting TLR/MyD88 signalling pathways in DCs and other myeloid cells during infection. While the general assumption that MyD88-dependent recognition by DCs is essential for inducing protective immunity holds true in some instances, the results surprisingly indicate a much more complex context-dependent requirement for this pathway in DCs and other myeloid or lymphoid cell-types in vivo. Furthermore, we highlight the advantages of Cre-mediated DC targeting approaches and their possible limitations. We also present future perspectives on the development of new genetic mouse models to target distinct DC subsets in vivo. Such models will serve to understand the functional heterogeneity of DCs in vivo.

  11. Suppressor of cytokine signaling 1 interacts with oncogenic lymphocyte-specific protein tyrosine kinase.

    PubMed

    Venkitachalam, Srividya; Chueh, Fu-Yu; Leong, King-Fu; Pabich, Samantha; Yu, Chao-Lan

    2011-03-01

    Lymphocyte-specific protein tyrosine kinase (Lck) plays a key role in T cell signal transduction and is tightly regulated by phosphorylation and dephosphorylation. Lck can function as an oncoprotein when overexpressed or constantly activated by mutations. Our previous studies showed that Lck-induced cellular transformation could be suppressed by enforced expression of suppressor of cytokine signaling 1 (SOCS1), a SOCS family member involved in the negative feedback control of cytokine signaling. We observed attenuated Lck kinase activity in SOCS1-expressing cells, suggesting an important role of SOCS in regulating Lck functions. It remains largely unknown whether and how SOCS proteins interact with the oncogenic Lck kinase. Here, we report that among four SOCS family proteins, SOCS1, SOCS2, SOCS3 and CIS (cytokine-inducible SH2 domain containing protein), SOCS1 has the highest affinity in binding to the oncogenic Lck kinase. We identified the positive regulatory phosphotyrosine 394 residue in the kinase domain as the key interacting determinant in Lck. Additionally, the Lck kinase domain alone is sufficient to bind SOCS1. While the SH2 domain in SOCS1 is important in its association with the oncogenic Lck kinase, other functional domains may also contribute to overall binding affinity. These findings provide important mechanistic insights into the role of SOCS proteins as tumor suppressors in cells transformed by oncogenic protein tyrosine kinases.

  12. 78 FR 22554 - Document to Support Submission of an Electronic Common Technical Document-Specifications for File...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-16

    ... HUMAN SERVICES Food and Drug Administration Document to Support Submission of an Electronic Common Technical Document--Specifications for File Format Types Using Electronic Common Technical Document Specifications; Availability AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food...

  13. The structure of Escherichia coli signal recognition particle revealed by scanning transmission electron microscopy.

    PubMed

    Mainprize, Iain L; Beniac, Daniel R; Falkovskaia, Elena; Cleverley, Robert M; Gierasch, Lila M; Ottensmeyer, F Peter; Andrews, David W

    2006-12-01

    Structural studies on various domains of the ribonucleoprotein signal recognition particle (SRP) have not converged on a single complete structure of bacterial SRP consistent with the biochemistry of the particle. We obtained a three-dimensional structure for Escherichia coli SRP by cryoscanning transmission electron microscopy and mapped the internal RNA by electron spectroscopic imaging. Crystallographic data were fit into the SRP reconstruction, and although the resulting model differed from previous models, they could be rationalized by movement through an interdomain linker of Ffh, the protein component of SRP. Fluorescence resonance energy transfer experiments determined interdomain distances that were consistent with our model of SRP. Docking our model onto the bacterial ribosome suggests a mechanism for signal recognition involving interdomain movement of Ffh into and out of the nascent chain exit site and suggests how SRP could interact and/or compete with the ribosome-bound chaperone, trigger factor, for a nascent chain during translation.

  14. Extensive and specific responses of a eukaryote to bacterial quorum-sensing signals

    PubMed Central

    Mathesius, Ulrike; Mulders, Susan; Gao, Mengsheng; Teplitski, Max; Caetano-Anollés, Gustavo; Rolfe, Barry G.; Bauer, Wolfgang D.

    2003-01-01

    Many bacteria use N-acyl homoserine lactone (AHL) signals to coordinate the behavior of individual cells in a local population. The successful infection of eukaryotic hosts by bacteria seems to depend particularly on such AHL-mediated “quorum-sensing” regulation. We have used proteome analysis to show that a eukaryotic host, the model legume Medicago truncatula, is able to detect nanomolar to micromolar concentrations of bacterial AHLs from both symbiotic (Sinorhizobium meliloti) and pathogenic (Pseudomonas aeruginosa) bacteria, and that it responds in a global manner by significant changes in the accumulation of over 150 proteins, 99 of which have been identified by peptide mass fingerprinting. The accumulation of specific proteins and isoforms depended on AHL structure, concentration, and time of exposure. AHLs were also found to induce tissue-specific activation of β-glucuronidase (GUS) reporter fusions to an auxin-responsive and three chalcone synthase promoters, consistent with AHL-induced changes in the accumulation of auxin-responsive and flavonoid synthesis proteins. In addition, exposure to AHLs was found to induce changes in the secretion of compounds by the plants that mimic quorum-sensing signals and thus have the potential to disrupt quorum sensing in associated bacteria. Our results indicate that eukaryotes have an extensive range of functional responses to AHLs that may play important roles in the beneficial or pathogenic outcomes of eukaryote–prokaryote interactions. PMID:12511600

  15. EphA4 signaling in juveniles establishes topographic specificity of structural plasticity in the hippocampus.

    PubMed

    Galimberti, Ivan; Bednarek, Ewa; Donato, Flavio; Caroni, Pico

    2010-03-11

    The formation and loss of synapses is involved in learning and memory. Distinct subpopulations of permanent and plastic synapses coexist in the adult brain, but the principles and mechanisms underlying the establishment of these distinctions remain unclear. Here we show that in the hippocampus, terminal arborizations (TAs) with high plasticity properties are specified at juvenile stages, and account for most synapse turnover of adult mossy fibers. Out of 9-12 giant terminals along CA3, distinct subpopulations of granule neurons revealed by mouse reporter lines exhibit 0, 1, or >2 TAs. TA specification involves a topographic rule based on cell body position and EphA4 signaling. Upon disruption of EphA4 signaling or PSA-NCAM in juvenile circuits, single-TA mossy fibers establish >2 TAs, suggesting that intra-axonal competition influences plasticity site selection. Therefore, plastic synapse specification in juveniles defines sites of synaptic remodeling in the adult, and hippocampal circuit plasticity follows unexpected topographic principles.

  16. Targeting autocrine HB-EGF signaling with specific ADAM12 inhibition using recombinant ADAM12 prodomain

    NASA Astrophysics Data System (ADS)

    Miller, Miles A.; Moss, Marcia L.; Powell, Gary; Petrovich, Robert; Edwards, Lori; Meyer, Aaron S.; Griffith, Linda G.; Lauffenburger, Douglas A.

    2015-10-01

    Dysregulation of ErbB-family signaling underlies numerous pathologies and has been therapeutically targeted through inhibiting ErbB-receptors themselves or their cognate ligands. For the latter, “decoy” antibodies have been developed to sequester ligands including heparin-binding epidermal growth factor (HB-EGF); however, demonstrating sufficient efficacy has been difficult. Here, we hypothesized that this strategy depends on properties such as ligand-receptor binding affinity, which varies widely across the known ErbB-family ligands. Guided by computational modeling, we found that high-affinity ligands such as HB-EGF are more difficult to target with decoy antibodies compared to low-affinity ligands such as amphiregulin (AREG). To address this issue, we developed an alternative method for inhibiting HB-EGF activity by targeting its cleavage from the cell surface. In a model of the invasive disease endometriosis, we identified A Disintegrin and Metalloproteinase 12 (ADAM12) as a protease implicated in HB-EGF shedding. We designed a specific inhibitor of ADAM12 based on its recombinant prodomain (PA12), which selectively inhibits ADAM12 but not ADAM10 or ADAM17. In endometriotic cells, PA12 significantly reduced HB-EGF shedding and resultant cellular migration. Overall, specific inhibition of ligand shedding represents a possible alternative to decoy antibodies, especially for ligands such as HB-EGF that exhibit high binding affinity and localized signaling.

  17. Synapse-specific compartmentalization of signaling cascades for LTP induction in CA3 interneurons.

    PubMed

    Galván, E J; Pérez-Rosello, T; Gómez-Lira, G; Lara, E; Gutiérrez, R; Barrionuevo, G

    2015-04-01

    Inhibitory interneurons with somata in strata radiatum and lacunosum-molecular (SR/L-M) of hippocampal area CA3 receive excitatory input from pyramidal cells via the recurrent collaterals (RCs), and the dentate gyrus granule cells via the mossy fibers (MFs). Here we demonstrate that Hebbian long-term potentiation (LTP) at RC synapses on SR/L-M interneurons requires the concomitant activation of calcium-impermeable AMPARs (CI-AMPARs) and N-methyl-d-aspartate receptors (NMDARs). RC LTP was prevented by voltage clamping the postsynaptic cell during high-frequency stimulation (HFS; 3 trains of 100 pulses delivered at 100 Hz every 10s), with intracellular injections of the Ca(2+) chelator BAPTA (20mM), and with the NMDAR antagonist D-AP5. In separate experiments, RC and MF inputs converging onto the same interneuron were sequentially activated. We found that RC LTP induction was blocked by inhibitors of the calcium/calmodulin-dependent protein kinase II (CaMKII; KN-62, 10 μM or KN-93, 10 μM) but MF LTP was CaMKII independent. Conversely, the application of the protein kinase A (PKA) activators forskolin/IBMX (50 μM/25 μM) potentiated MF EPSPs but not RC EPSPs. Together these data indicate that the aspiny dendrites of SR/L-M interneurons compartmentalize synapse-specific Ca(2+) signaling required for LTP induction at RC and MF synapses. We also show that the two signal transduction cascades converge to activate a common effector, protein kinase C (PKC). Specifically, LTP at RC and MF synapses on the same SR/LM interneuron was blocked by postsynaptic injections of chelerythrine (10 μM). These data indicate that both forms of LTP share a common mechanism involving PKC-dependent signaling modulation. PMID:25637803

  18. Synapse-specific compartmentalization of signaling cascades for LTP induction in CA3 interneurons

    PubMed Central

    Galván, Emilio J; Pérez-Rosello, Tamara; Gómez-Lira, Gisela; Lara, Erika; Gutiérrez, Rafael; Barrionuevo, Germán

    2015-01-01

    Inhibitory interneurons with somata in strata radiatum and lacunosun-moleculare (SR/L-M) of hippocampal area CA3 receive excitatory input from pyramidal cells via the recurrent collaterals (RC), and the dentate gyrus granule cells via the mossy fibers (MFs). Here we demonstrate that Hebbian long-term potentiation (LTP) at RC synapses on SR/L-M interneurons requires the concomitant activation of calcium-impermeable AMPARs (CI- AMPARs) and NMDARs. RC LTP was prevented by voltage clamping the postsynaptic cell during high-frequency stimulation (HFS; 3 trains of 100 pulses delivered at 100 Hz every 10 s), with intracellular injections of the Ca2+ chelator BAPTA (20 mM), and with the N-methyl-D-aspartate receptor (NMDAR) antagonist D-AP5. In separate experiments, RC and MF inputs converging onto the same interneuron were sequentially activated. We found that RC LTP induction was blocked by inhibitors of the calcium/calmodulin-dependent protein kinase II (CaMKII; KN-62, 10 μM or KN-93, 10 μM) but MF LTP was CaMKII independent. Conversely, the application of the protein kinase A (PKA) activators forskolin/IBMX(50 μM/25 μM) potentiated MF EPSPs but not RC EPSPs. Together these data indicate that the aspiny dendrites of SR/L-M interneurons compartmentalize synaptic-specific Ca2+ signaling required for LTP induction at RC and MF synapses. We also show that the two signal transduction cascades converge to activate a common effector, protein kinase C (PKC). Specifically, LTP at RC and MF synapses on the same SR/LM interneuron was blocked by postsynaptic injections of chelerythrine (10 μM). These data indicate that both forms of LTP share a common mechanism involving PKC-dependent signaling modulation. PMID:25637803

  19. Interaction of the Arabidopsis UV-B-specific signaling component UVR8 with chromatin.

    PubMed

    Cloix, Catherine; Jenkins, Gareth I

    2008-01-01

    Arabidopsis UV RESISTANCE LOCUS8 (UVR8) is a UV-B-specific signaling component that regulates expression of a range of genes concerned with UV protection. Here, we investigate the interaction of UVR8 with chromatin. Using antibodies specific to UVR8 in chromatin immunoprecipitation (ChIP) assays with wild-type plants, we show that native UVR8 binds to chromatin in vivo. Similar experiments using an anti-GFP antibody with plants expressing a GFP-UVR8 fusion show that UVR8 associates with a relatively small region of chromatin containing the HY5 gene. UVR8 interacts with chromatin containing the promoter regions of other genes, but not with all the genes it regulates. UV-B is not required for the interaction of UVR8 with chromatin because association with several gene loci is observed in the absence of UV-B. Pull-down assays demonstrate that UVR8 associates with histones in vivo and competition experiments indicate that the interaction is preferentially with histone H2B. ChIP experiments using antibodies that recognize specific histone modifications indicate that the UV-B-stimulated transcription of some genes may be correlated with histone modification. In particular, the ELIP1 promoter showed a significant enrichment of diacetyl histone H3 (K9/K14) following UV-B exposure. These findings increase understanding of the interaction of the key UV-B-specific regulator UVR8 with chromatin.

  20. A low-power electronic nose signal-processing chip for a portable artificial olfaction system.

    PubMed

    Kea-Tiong Tang; Shih-Wen Chiu; Meng-Fan Chang; Chih-Cheng Hsieh; Jyuo-Min Shyu

    2011-08-01

    The bulkiness of current electronic nose (E-Nose) systems severely limits their portability. This study designed and fabricated an E-Nose signal-processing chip by using TSMC 0.18-μ m 1P6M complementary metal-oxide semiconductor technology to overcome the need to connect the device to a personal computer, which has traditionally been a major stumbling block in reducing the size of E-Nose systems. The proposed chip is based on a conductive polymer sensor array chip composed of multiwalled carbon nanotubes. The signal-processing chip comprises an interface circuit, an analog-to-digital converter, a memory module, and a microprocessor embedded with a pattern-recognition algorithm. Experimental results have verified the functionality of the proposed system, in which the E-Nose signal-processing chip successfully classified three odors, carbon tetrachloride (CCl4), chloroform (CHCl3), and 2-Butanone (MEK), demonstrating its potential for portable applications. The power consumption of this signal-processing chip was maintained at a very low 2.81 mW using a 1.8-V power supply, making it highly suitable for integration as an electronic nose system-on-chip.

  1. Persistent free radical ESR signals in marine bivalve tissues. [Electron Spin Resonance (ESR)

    SciTech Connect

    Mehlorn, R.J. . Dept. of Materials Science and Mineral Engineering); Mendez, A.T. ); Higashi, R. . Bodega Marine Lab.); Fan, T. )

    1992-08-01

    Freeze-dried homogenates of the oyster Crassostrea rhizophorae collected from waters in Puerto Rico near urban and industrial sites as well as at relatively pristine locations yielded electron spin resonance (ESR) spectra characteristic of free radicals as well as spectral components of transition metal ions, dominated by manganese. The magnitudes of these ESR signals and the concentrations of trace elements (determined by X-ray fluorescence) varied considerably among oyster samples, masking any potential correlation with polluted waters. Laboratory studies were initiated to identify the factors controlling the magnitudes of the tissue free radical ESR signals. Another mollusc, Mytilus californianus collected at the Bodega Marine laboratory in northern California, was fractionated into goneds and remaining tissue. Freeze-dried homogenates of both fractions exhibited ESR signals that increased gradually with time. ESR signals were observed in freeze-dried perchloric acid (PCA) precipitates of the homogenates, delipidated PCA precipitates, and in chloroform extracts of these precipitates. Acid hydrolysis to degrade proteins to amino acids produced a residue, which yielded much larger ESR free radical signals after freeze-drying. Freshly thawed homogenates of Crassostrea rhizophorae also exhibited ESR signals. A laboratory model of copper stress in Crassostrea rhizophorae was developed to study the effect of this transition metal on dssue free radicals. Preliminary results suggested that sublethal copper exposure had little effect on tissue fire radicals, except possibly for a signal enhancement in an oyster fraction that was enriched in kidney granules. Since kidney granules are known to accumulate heavy metals in mussels and probably other marine bivalves, this signal enhancement may prove to be an indicator of free radical processes associated with heavy metal deposition in molluscs.

  2. Different intracellular signalling pathways triggered by an anti-prolactin receptor (PRLR) antibody: Implication for a signal-specific PRLR agonist.

    PubMed

    Kan, Quan-E; Su, Yong; Yang, Huihui; Man, Hua

    2016-01-01

    In this work, we prepared a panel of monoclonal antibodies directed against prolactin receptor (PRLR) using the hybridoma technique. Of these monoclonal antibodies (Mabs), the Mab designated B6 was chosen for further characterization based on its biological activity. We first demonstrated that B6 can specifically bind to the prolactin receptor (PRLR) expressed on target cells by immunoprecipitation and Western blotting analysis. Subsequently, epitope mapping studies using a competitive receptor-binding assay indicated that B6 epitopes partially overlapped with those of prolactin (PRL). We then examined the resulting signal transduction pathways activated by this antibody in T-47D and CHO-PRLR cells and found that B6 induced different intracellular signalling compared with prolactin, which activates serine-threonine kinase (AKT), extracellular signal-regulated kinase 1/2 (ERK1/2), signal transducer and activator of transcription1 (STAT1) and STAT3 but not STAT5. The present study suggests that: (a) B6 may be a signal-specific prolactin receptor (PRLR) agonist; (b) B6 may be a biological reagent that can be used to explore the mechanism of PRLR-mediated intracellular signalling. In addition, this work also implies a strategy for preparing signal-specific cytokine agonists.

  3. Electron specific absorbed fractions for the adult male and female ICRP/ICRU reference computational phantoms.

    PubMed

    Zankl, Maria; Schlattl, Helmut; Petoussi-Henss, Nina; Hoeschen, Christoph

    2012-07-21

    The calculation of radiation dose from internally incorporated radionuclides is based on so-called absorbed fractions (AFs) and specific absorbed fractions (SAFs). SAFs for monoenergetic electrons were calculated for 63 source regions and 67 target regions using the new male and female adult reference computational phantoms adopted by the ICRP and ICRU and the Monte Carlo radiation transport programme package EGSnrc. The SAF values for electrons are opposed to the simplifying assumptions of ICRP Publication 30. The previously applied assumption of electrons being fully absorbed in the source organ itself is not always true at electron energies above approximately 300-500 keV. High-energy electrons have the ability to leave the source organ and, consequently, the electron SAFs for neighbouring organs can reach the same magnitude as those for photons for electron energies above 1 MeV. The reciprocity principle known for photons can be extended to electron SAFs as well, thus making cross-fire electron SAFs mass-independent. To quantify the impact of the improved electron dosimetry in comparison to the dosimetry using the simple assumptions of ICRP Publication 30, absorbed doses per administered activity of three radiopharmaceuticals were evaluated with and without explicit electron transport. The organ absorbed doses per administered activity for the two evaluation methods agree within 2%-3% for most organs for radionuclides with decay spectra having electron energies below a few hundred keV and within approximately 20% if higher electron energies are involved. An important exception is the urinary bladder wall, where the dose is overestimated by 60-150% using the simplified ICRP 30 approach for the radiopharmaceuticals of this study.

  4. Detection of electron emission as DLTS signal in CdTe solar cells

    NASA Astrophysics Data System (ADS)

    Ding, Y. M.; Cheng, Z.; Tan, X.; Misra, D.; Delahoy, A. E.; Chin, K. K.

    2016-10-01

    This work identifies an incongruity in the detection of the minority carrier signal in CdTe solar cells during the deep level transient spectroscopy (DLTS) measurement. Use of quasi-Fermi level instead of Fermi level of majority carriers to estimate the probability of emitting carriers seems to correct the ambiguity. During the experiment, signals from minority carrier traps (electron traps) were detected by using a long filling pulse time instead of an electron injection pulse. The DLTS measurements of CdTe solar cells observed a single electron trap with energy level EE1 = 0.47 eV, and two hole traps with energy levels, EH1 = 0.17 eV and EH2 = 0.27 eV. The possibility of any impact from the back contact was excluded, and the phenomenon was clarified by the simulation. It was further observed that when the condition of quasi-Fermi level is considered, the results of calculated probability were significantly different from that of the results that used only Fermi level of majority carriers. The simulations further aided the explanation of the defect behavior in DLTS measurements and the overlapping phenomenon of the capacitance spectrum of hole and electron traps.

  5. The legalities and practicalities of developing a course-specific electronic reserve room.

    PubMed

    Curran, Mary A; Curran, Kent E

    2002-01-01

    This article discusses important issues related to maintaining the currency of readings in a nursing course. The development of a course-specific electronic reserve room is offered as a methodology for achieving both timeliness and simplified distribution of course readings. The article reviews legal issues related to the development of an electronic reserve room for internet access. In addition, hardware and software issues related to the transference of paper materials to a digital format are considered. PMID:12503469

  6. Identification of signals that facilitate isoform specific nucleolar localization of myosin IC

    SciTech Connect

    Schwab, Ryan S.; Ihnatovych, Ivanna; Yunus, Sharifah Z.S.A.; Domaradzki, Tera; Hofmann, Wilma A.

    2013-05-01

    Myosin IC is a single headed member of the myosin superfamily that localizes to the cytoplasm and the nucleus, where it is involved in transcription by RNA polymerases I and II, intranuclear transport, and nuclear export. In mammalian cells, three isoforms of myosin IC are expressed that differ only in the addition of short isoform-specific N-terminal peptides. Despite the high sequence homology, the isoforms show differences in cellular distribution, in localization to nuclear substructures, and in their interaction with nuclear proteins through yet unknown mechanisms. In this study, we used EGFP-fusion constructs that express truncated or mutated versions of myosin IC isoforms to detect regions that are involved in isoform-specific localization. We identified two nucleolar localization signals (NoLS). One NoLS is located in the myosin IC isoform B specific N-terminal peptide, the second NoLS is located upstream of the neck region within the head domain. We demonstrate that both NoLS are functional and necessary for nucleolar localization of specifically myosin IC isoform B. Our data provide a first mechanistic explanation for the observed functional differences between the myosin IC isoforms and are an important step toward our understanding of the underlying mechanisms that regulate the various and distinct functions of myosin IC isoforms. - Highlights: ► Two NoLS have been identified in the myosin IC isoform B sequence. ► Both NoLS are necessary for myosin IC isoform B specific nucleolar localization. ► First mechanistic explanation of functional differences between the isoforms.

  7. Modulation of Notch signaling by antibodies specific for the extracellular negative regulatory region of NOTCH3.

    PubMed

    Li, Kang; Li, Yucheng; Wu, Wenjuan; Gordon, Wendy R; Chang, David W; Lu, Mason; Scoggin, Shane; Fu, Tihui; Vien, Long; Histen, Gavin; Zheng, Ji; Martin-Hollister, Rachel; Duensing, Thomas; Singh, Sanjaya; Blacklow, Stephen C; Yao, Zhengbin; Aster, Jon C; Zhou, Bin-Bing S

    2008-03-21

    The Notch pathway regulates the development of many tissues and cell types and is involved in a variety of human diseases, making it an attractive potential therapeutic target. This promise has been limited by the absence of potent inhibitors or agonists that are specific for individual human Notch receptors (NOTCH1-4). Using an unbiased functional screening, we identified monoclonal antibodies that specifically inhibit or induce activating proteolytic cleavages in NOTCH3. Remarkably, the most potent inhibitory and activating antibodies bind to overlapping epitopes within a juxtamembrane negative regulatory region that protects NOTCH3 from proteolysis and activation in its resting autoinhibited state. The inhibitory antibodies revert phenotypes conveyed on 293T cells by NOTCH3 signaling, such as increased cellular proliferation, survival, and motility, whereas the activating antibody mimics some of the effects of ligand-induced Notch activation. These findings provide insights into the mechanisms of Notch autoinhibition and activation and pave the way for the further development of specific antibody-based modulators of the Notch receptors, which are likely to be of utility in a wide range of experimental and therapeutic settings. PMID:18182388

  8. Role of glucose in IRS signaling in rat pancreatic islets: specific effects and interplay with insulin.

    PubMed

    Paris, Maryline; Bernard-Kargar, Catherine; Vilar, José; Kassis, Nadim; Ktorza, Alain

    2004-01-01

    We investigated the possible interplay between insulin and glucose signaling pathways in rat pancreatic beta-cell with a special focus on the role of glucose in IRS signaling in vivo. Three groups of rats were constituted by combining simultaneous infusion during 48 h either of glucose and/or insulin, or glucose+diazoxide: Hyperglycemic-Hyperinsulinemic (HGHI), euglycemic-Hyperinsulinemic (eGHI), Hyperglycemic-euinsulinemic (HGeI). Control rats were infused with 0,9%NaCl. In HGHI and HGeI rats plasma glucose levels were maintained at 20-22 mmol/l. In eGHI rats, plasma glucose was not different from that of controls, whereas plasma insulin was much higher than in controls. In HGHI rats, IRS-2 mRNA expression, total protein and phosphorylated protein amounts were increased compared to controls. In HGeI rats, only IRS-2 mRNA expression was increased. No change was observed in eGHI rats whatever the parameter considered. In all groups, mRNA concentration of IRS-1 was similar to that of controls. The quantity of total and phosphorylated IRS-1 protein was dramatically increased in HGHI rats and to a lesser extent in eGHI rats. Neither mRNA nor IRS-1 protein expression were modified in HGeI rats. The data suggest that glucose and insulin play at once a specific and a complementary role in islet IRSs signaling. Especially, glucose stimulates IRS-2 mRNA expression whatever the insulin status and independently of the secretory process. The differential regulation of IRS-1 and IRS-2 expressions is in agreement with their supposed different involvement in the control of beta-cell growth and function.

  9. Transmitter-induced modulation of subionospheric VLF signals: Ionospheric heating rather than electron precipitation

    NASA Astrophysics Data System (ADS)

    Graf, K. L.; Inan, U. S.; Spasojevic, M.

    2011-12-01

    The controlled keying of ground-based VLF transmitters with periodic on/off sequences allows the detection of weak but measurable cross-modulation effects on other subionospheric VLF probe signals used for VLF remote sensing. In this paper, we reexamine previously published and additional cases of such events and determine that the initial interpretations of such cross modulation as being due to electron precipitation is likely incorrect. Rather, such events appear to be fully consistent with ionospheric heating caused by the keyed signal, even when the probe VLF signal path lies thousands of kilometers from the heating VLF transmitter. The 21.4 kHz transmitter NPM located in Lualualei, Hawaii, is keyed on/off in periodic sequences, and that same periodicity is observed on the subionospherically propagating probe signal generated by the 24.8 kHz transmitter NLK of Jim Creek, Washington. Previous initial conclusions published for these experiments do not hold under detailed review due to the lack of discernible onset delay and lag time in the observed perturbations, which eliminates transmitter-induced precipitation of electron radiation as a possible cause. Detailed testing of the receiver shows instrumental cross-modulation to not be a concern in these observations. It is thus concluded that the observed perturbations, despite occurring on a probe signal pathway that is 1750 km away from NPM at its point of closest approach, are due to direct ionospheric heating by the keyed VLF transmitter NPM. Results indicate that the VLF transmitter may affect the overlying ionosphere over much larger lateral regions than previously believed.

  10. Axon Branch-Specific Semaphorin-1a Signaling in Drosophila Mushroom Body Development

    PubMed Central

    Zwarts, Liesbeth; Goossens, Tim; Clements, Jason; Kang, Yuan Y.; Callaerts, Patrick

    2016-01-01

    Correct wiring of the mushroom body (MB) neuropil in the Drosophila brain involves appropriate positioning of different axonal lobes, as well as the sister branches that develop from individual axons. This positioning requires the integration of various guidance cues provided by different cell types, which help the axons find their final positions within the neuropil. Semaphorins are well-known for their conserved roles in neuronal development and axon guidance. We investigated the role of Sema-1a in MB development more closely. We show that Sema-1a is expressed in the MBs as well as surrounding structures, including the glial transient interhemispheric fibrous ring, throughout development. By loss- and gain-of-function experiments, we show that the MB axons display lobe and sister branch-specific Sema-1a signaling, which controls different aspects of axon outgrowth and guidance. Furthermore, we demonstrate that these effects are modulated by the integration of MB intrinsic and extrinsic Sema-1a signaling pathways involving PlexA and PlexB. Finally, we also show a role for neuronal- glial interaction in Sema-1a dependent β-lobe outgrowth. PMID:27656129

  11. Axon Branch-Specific Semaphorin-1a Signaling in Drosophila Mushroom Body Development

    PubMed Central

    Zwarts, Liesbeth; Goossens, Tim; Clements, Jason; Kang, Yuan Y.; Callaerts, Patrick

    2016-01-01

    Correct wiring of the mushroom body (MB) neuropil in the Drosophila brain involves appropriate positioning of different axonal lobes, as well as the sister branches that develop from individual axons. This positioning requires the integration of various guidance cues provided by different cell types, which help the axons find their final positions within the neuropil. Semaphorins are well-known for their conserved roles in neuronal development and axon guidance. We investigated the role of Sema-1a in MB development more closely. We show that Sema-1a is expressed in the MBs as well as surrounding structures, including the glial transient interhemispheric fibrous ring, throughout development. By loss- and gain-of-function experiments, we show that the MB axons display lobe and sister branch-specific Sema-1a signaling, which controls different aspects of axon outgrowth and guidance. Furthermore, we demonstrate that these effects are modulated by the integration of MB intrinsic and extrinsic Sema-1a signaling pathways involving PlexA and PlexB. Finally, we also show a role for neuronal- glial interaction in Sema-1a dependent β-lobe outgrowth.

  12. Dense fibrillar collagen is a potent inducer of invadopodia via a specific signaling network

    PubMed Central

    Swatkoski, Stephen; Matsumoto, Kazue; Campbell, Catherine B.; Petrie, Ryan J.; Dimitriadis, Emilios K.; Li, Xin; Mueller, Susette C.; Bugge, Thomas H.; Gucek, Marjan

    2015-01-01

    Cell interactions with the extracellular matrix (ECM) can regulate multiple cellular activities and the matrix itself in dynamic, bidirectional processes. One such process is local proteolytic modification of the ECM. Invadopodia of tumor cells are actin-rich proteolytic protrusions that locally degrade matrix molecules and mediate invasion. We report that a novel high-density fibrillar collagen (HDFC) matrix is a potent inducer of invadopodia, both in carcinoma cell lines and in primary human fibroblasts. In carcinoma cells, HDFC matrix induced formation of invadopodia via a specific integrin signaling pathway that did not require growth factors or even altered gene and protein expression. In contrast, phosphoproteomics identified major changes in a complex phosphosignaling network with kindlin2 serine phosphorylation as a key regulatory element. This kindlin2-dependent signal transduction network was required for efficient induction of invadopodia on dense fibrillar collagen and for local degradation of collagen. This novel phosphosignaling mechanism regulates cell surface invadopodia via kindlin2 for local proteolytic remodeling of the ECM. PMID:25646088

  13. Axon Branch-Specific Semaphorin-1a Signaling in Drosophila Mushroom Body Development.

    PubMed

    Zwarts, Liesbeth; Goossens, Tim; Clements, Jason; Kang, Yuan Y; Callaerts, Patrick

    2016-01-01

    Correct wiring of the mushroom body (MB) neuropil in the Drosophila brain involves appropriate positioning of different axonal lobes, as well as the sister branches that develop from individual axons. This positioning requires the integration of various guidance cues provided by different cell types, which help the axons find their final positions within the neuropil. Semaphorins are well-known for their conserved roles in neuronal development and axon guidance. We investigated the role of Sema-1a in MB development more closely. We show that Sema-1a is expressed in the MBs as well as surrounding structures, including the glial transient interhemispheric fibrous ring, throughout development. By loss- and gain-of-function experiments, we show that the MB axons display lobe and sister branch-specific Sema-1a signaling, which controls different aspects of axon outgrowth and guidance. Furthermore, we demonstrate that these effects are modulated by the integration of MB intrinsic and extrinsic Sema-1a signaling pathways involving PlexA and PlexB. Finally, we also show a role for neuronal- glial interaction in Sema-1a dependent β-lobe outgrowth. PMID:27656129

  14. Quantitative Site-Specific Phosphoproteomics of Trichoderma reesei Signaling Pathways upon Induction of Hydrolytic Enzyme Production.

    PubMed

    Nguyen, Elizabeth V; Imanishi, Susumu Y; Haapaniemi, Pekka; Yadav, Avinash; Saloheimo, Markku; Corthals, Garry L; Pakula, Tiina M

    2016-02-01

    The filamentous fungus Trichoderma reesei is used for industrial production of secreted enzymes including carbohydrate active enzymes, such as cellulases and hemicellulases. The production of many of these enzymes by T. reesei is influenced by the carbon source it grows on, where the regulation system controlling hydrolase genes involves various signaling pathways. T. reesei was cultivated in the presence of sorbitol, a carbon source that does not induce the production of cellulases and hemicellulases, and then exposed to either sophorose or spent-grain extract, which are efficient inducers of the enzyme production. Specific changes at phosphorylation sites were investigated in relation to the production of cellulases and hemicellulases using an MS-based framework. Proteome-wide phosphorylation following carbon source exchange was investigated in the early stages of induction: 0, 2, 5, and 10 min. The workflow involved sequential trypsin digestion, TiO2 enrichment, and MS analysis using a Q Exactive mass spectrometer. We report on the identification and quantitation of 1721 phosphorylation sites. Investigation of the data revealed a complex signaling network activated upon induction involving components related to light-mediated cellulase induction, osmoregulation, and carbon sensing. Changes in protein phosphorylation were detected in the glycolytic pathway, suggesting an inhibition of glucose catabolism at 10 min after the addition of sophorose and as early as 2 min after the addition of spent-grain extract. Differential phosphorylation of factors related to carbon storage, intracellular trafficking, cytoskeleton, and cellulase gene regulation were also observed.

  15. Wnt/β-catenin signaling in midbrain dopaminergic neuron specification and neurogenesis.

    PubMed

    Joksimovic, Milan; Awatramani, Rajeshwar

    2014-02-01

    Loss of midbrain dopaminergic (mDA) neurons underlies the motor symptoms of Parkinson's disease. Towards cell replacement, studies have focused on mechanisms underlying embryonic mDA production, as a rational basis for deriving mDA neurons from stem cells. We will review studies of β-catenin, an obligate component of the Wnt cascade that is critical to mDA specification and neurogenesis. mDA neurons have a unique origin--the midbrain floor plate (FP). Unlike the hindbrain and spinal cord FP, the midbrain FP is highly neurogenic and Wnt/β-catenin signaling is critical to this difference in neurogenic potential. In β-catenin loss-of-function experiments, the midbrain FP resembles the hindbrain FP, and key mDA progenitor genes such as Otx2, Lmx1a, Msx1, and Ngn2 are downregulated whereas Shh is maintained. Accordingly, the neurogenic capacity of the midbrain FP is diminished, resulting in fewer mDA neurons. Conversely, in β-catenin gain-of-function experiments, the hindbrain FP expresses key mDA progenitor genes, and is highly neurogenic. Interestingly, when excessive β-catenin is supplied to the midbrain FP, less mDA neurons are produced suggesting that the dosage of Wnt/β-catenin signaling is critical. These studies of β-catenin have facilitated new protocols to derive mDA neurons from stem cells.

  16. MAP kinases with distinct inhibitory functions impart signaling specificity during yeast differentiation.

    PubMed

    Madhani, H D; Styles, C A; Fink, G R

    1997-11-28

    Filamentous invasive growth of S. cerevisiae requires multiple elements of the mitogen-activated protein kinase (MAPK) signaling cascade that are also components of the mating pheromone response pathway. Here we show that, despite sharing several constituents, the two pathways use different MAP kinases. The Fus3 MAPK regulates mating, whereas the Kss1 MAPK regulates filamentation and invasion. Remarkably, in addition to their kinase-dependent activation functions, Kss1 and Fus3 each have a distinct kinase-independent inhibitory function. Kss1 inhibits the filamentation pathway by interacting with its target transcription factor Ste12. Fus3 has a different inhibitory activity that prevents the inappropriate activation of invasion by the pheromone response pathway. In the absence of Fus3, there is erroneous crosstalk in which mating pheromone now activates filamentation-specific gene expression using the Kss1 MAPK. PMID:9393860

  17. A Physiological Signal Transmission Model to be Used for Specific Diagnosis of Cochlear Impairments

    NASA Astrophysics Data System (ADS)

    Saremi, Amin; Stenfelt, Stefan

    2011-11-01

    Many of the sophisticated characteristics of human auditory system are attributed to cochlea. Also, most of patients with a hearing loss suffer from impairments that originate from cochlea (sensorineural). Despite this, today's clinical diagnosis methods do not probe the specific origins of such cochlear lesions. The aim of this research is to introduce a physiological signal transmission model to be clinically used as a tool for diagnosis of cochlear losses. This model enables simulation of different bio-mechano-electrical processes which occur in the auditory organ of Corti inside the cochlea. What makes this model different from many available computational models is its loyalty to physiology since the ultimate goal is to model each single physiological phenomenon. This includes passive BM vibration, outer hair cells' performances such as nonlinear mechanoelectrical transduction (MET), active amplifications by somatic motor, as well as vibration to neural conversion at the inner hair cells.

  18. Manipulation of Mitogen-Activated Protein Kinase Kinase Signaling in the Arabidopsis Stomatal Lineage Reveals Motifs That Contribute to Protein Localization and Signaling Specificity[W][OPEN

    PubMed Central

    Lampard, Gregory R.; Wengier, Diego L.; Bergmann, Dominique C.

    2014-01-01

    When multiple mitogen-activated protein kinase (MAPK) components are recruited recurrently to transduce signals of different origins, and often opposing outcomes, mechanisms to enforce signaling specificity are of utmost importance. These mechanisms are largely uncharacterized in plant MAPK signaling networks. The Arabidopsis thaliana stomatal lineage was previously used to show that when rendered constitutively active, four MAPK kinases (MKKs), MKK4/5/7/9, are capable of perturbing stomatal development and that these kinases comprise two pairs, MKK4/5 and MKK7/9, with both overlapping and divergent functions. We characterized the contributions of specific structural domains of these four “stomatal” MKKs to MAPK signaling output and specificity both in vitro and in vivo within the three discrete cell types of the stomatal lineage. These results verify the influence of functional docking (D) domains of MKKs on MAPK signal output and identify novel regulatory functions for previously uncharacterized structures within the N termini of MKK4/5. Beyond this, we present a novel function of the D-domains of MKK7/9 in regulating the subcellular localization of these kinases. These results provide tools to broadly assess the extent to which these and additional motifs within MKKs function to regulate MAPK signal output throughout the plant. PMID:25172143

  19. Reversing the Signaled Magnitude Effect in Delayed Matching to Sample: Delay-Specific Remembering?

    ERIC Educational Resources Information Center

    White, K. Geoffrey; Brown, Glenn S.

    2011-01-01

    Pigeons performed a delayed matching-to-sample task in which large or small reinforcers for correct remembering were signaled during the retention interval. Accuracy was low when small reinforcers were signaled, and high when large reinforcers were signaled (the signaled magnitude effect). When the reinforcer-size cue was switched from small to…

  20. Small signal gain based on analytic models of thin intense electron beams

    NASA Astrophysics Data System (ADS)

    James Elliott, C.; McVey, Brian; Schmitt, Mark

    1991-07-01

    We develop the free electron laser theory of the effective energy distribution and the small signal gain for a thin electron beam. The assumption of thinness allows us to treat various transverse locations and electron beam trajectory angles as introducing phase shifts that have the same effect as those introduced by a change in energy of the electron. These ideas extend previous work of Colson et al., Dattoli et al., Scharlemann, and others in five important ways. The first is the ability to treat electron beams with three different classes of matching or symmetry conditions: (i) electron beams with separate betatron matching in each plane. (ii) those with aspect ratio matching, and (iii) crossed matched beams. Manifestations of these symmetries include elliptical cross-sections and electron beams that have modulated spatial profiles. For these we derive analytical expressions for effective energy distributions. Second, two emittance parameters for the electron beam are shown to consolidate into a single parameter that describes most of the energy variation of the effective energy distributions. Thus, the effective energy distribution for a 1:4 ribbon electron beam is nearly equivalent to a distribution for a beam of circular cross-section. Third, these calculations extend to energy distributions, angular distributions, and spatial distributions that all follow Gaussian profiles. Fourth, this model incorporates the description of the incident Gaussian optical beam and the above electron beam dynamics into a single influence function kernel. Emittance, energy spread, diffraction, and gain may be interpreted as limiting the length over which the bunching contributions of the propagating electric fields downstream are important. Fifth, three-dimensional profiles of the optical fields are computed. This work is complementary to the recent work of Yu, Krinsky and Gluckstern in that ours always describes the transition from low gain to high gain for a thin beam and not

  1. 45 CFR 170.205 - Content exchange standards and implementation specifications for exchanging electronic health...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Specification (incorporated by reference in § 170.299). (e) Electronic submission to immunization registries.... Implementation Guide for Immunization Data Transactions using Version 2.3.1 of the Health Level Seven (HL7... Implementation Guide for Immunization Messaging Release 1.0 (incorporated by reference in § 170.299). (f)...

  2. Sequence-specific DNA detection at 10 fM by electromechanical signal transduction.

    PubMed

    Esfandiari, Leyla; Lorenzini, Michael; Kocharyan, Gayane; Monbouquette, Harold G; Schmidt, Jacob J

    2014-10-01

    Target DNA fragments at 10 fM concentration (approximately 6 × 10(5) molecules) were detected against a DNA background simulating the noncomplementary genomic DNA present in real samples using a simple, PCR-free, optics-free approach based on electromechanical signal transduction. The development of a rapid, sensitive, and cost-effective nucleic acid detection platform is highly desired for a range of diverse applications. We previously described a potentially low-cost device for sequence-specific nucleic acid detection based on conductance change measurement of a pore blocked by electrophoretically mobilized bead-(peptide nucleic acid probe) conjugates upon hybridization with target nucleic acid. Here, we demonstrate the operation of our device with longer DNA targets, and we describe the resulting improvement in the limit of detection (LOD). We investigated the detection of DNA oligomers of 110, 235, 419, and 1613 nucleotides at 1 pM to 1 fM and found that the LOD decreased as DNA length increased, with 419 and 1613 nucleotide oligomers detectable down to 10 fM. In addition, no false positive responses were obtained with noncomplementary, control DNA fragments of similar length. The 1613-base DNA oligomer is similar in size to 16S rRNA, which suggests that our device may be useful for detection of pathogenic bacteria at clinically relevant concentrations based on recognition of species-specific 16S rRNA sequences.

  3. DC-ATLAS: a systems biology resource to dissect receptor specific signal transduction in dendritic cells

    PubMed Central

    2010-01-01

    Background The advent of Systems Biology has been accompanied by the blooming of pathway databases. Currently pathways are defined generically with respect to the organ or cell type where a reaction takes place. The cell type specificity of the reactions is the foundation of immunological research, and capturing this specificity is of paramount importance when using pathway-based analyses to decipher complex immunological datasets. Here, we present DC-ATLAS, a novel and versatile resource for the interpretation of high-throughput data generated perturbing the signaling network of dendritic cells (DCs). Results Pathways are annotated using a novel data model, the Biological Connection Markup Language (BCML), a SBGN-compliant data format developed to store the large amount of information collected. The application of DC-ATLAS to pathway-based analysis of the transcriptional program of DCs stimulated with agonists of the toll-like receptor family allows an integrated description of the flow of information from the cellular sensors to the functional outcome, capturing the temporal series of activation events by grouping sets of reactions that occur at different time points in well-defined functional modules. Conclusions The initiative significantly improves our understanding of DC biology and regulatory networks. Developing a systems biology approach for immune system holds the promise of translating knowledge on the immune system into more successful immunotherapy strategies. PMID:21092113

  4. EphB receptor forward signaling regulates area-specific reciprocal thalamic and cortical axon pathfinding

    PubMed Central

    Robichaux, Michael A.; Chenaux, George; Ho, Hsin-Yi Henry; Soskis, Michael J.; Dravis, Christopher; Kwan, Kenneth Y.; Šestan, Nenad; Greenberg, Michael Eldon; Henkemeyer, Mark; Cowan, Christopher W.

    2014-01-01

    In early brain development, ascending thalamocortical axons (TCAs) navigate through the ventral telencephalon (VTel) to reach their target regions in the young cerebral cortex. Descending, deep-layer cortical axons subsequently target appropriate thalamic and subcortical target regions. However, precisely how and when corticothalamic axons (CTAs) identify their appropriate, reciprocal thalamic targets remains unclear. We show here that EphB1 and EphB2 receptors control proper navigation of a subset of TCA and CTA projections through the VTel. We show in vivo that EphB receptor forward signaling and the ephrinB1 ligand are required during the early navigation of L1-CAM+ thalamic fibers in the VTel, and that the misguided thalamic fibers in EphB1/2 KO mice appear to interact with cortical subregion-specific axon populations during reciprocal cortical axon guidance. As such, our findings suggest that descending cortical axons identify specific TCA subpopulations in the dorsal VTel to coordinate reciprocal cortical–thalamic connectivity in the early developing brain. PMID:24453220

  5. Caenorhabditis elegans TRPV channels function in a modality-specific pathway to regulate response to aberrant sensory signaling.

    PubMed

    Ezak, Meredith J; Hong, Elizabeth; Chaparro-Garcia, Angela; Ferkey, Denise M

    2010-05-01

    Olfaction and some forms of taste (including bitter) are mediated by G protein-coupled signal transduction pathways. Olfactory and gustatory ligands bind to chemosensory G protein-coupled receptors (GPCRs) in specialized sensory cells to activate intracellular signal transduction cascades. G protein-coupled receptor kinases (GRKs) are negative regulators of signaling that specifically phosphorylate activated GPCRs to terminate signaling. Although loss of GRK function usually results in enhanced cellular signaling, Caenorhabditis elegans lacking GRK-2 function are not hypersensitive to chemosensory stimuli. Instead, grk-2 mutant animals do not chemotax toward attractive olfactory stimuli or avoid aversive tastes and smells. We show here that loss-of-function mutations in the transient receptor potential vanilloid (TRPV) channels OSM-9 and OCR-2 selectively restore grk-2 behavioral avoidance of bitter tastants, revealing modality-specific mechanisms for TRPV channel function in the regulation of C. elegans chemosensation. Additionally, a single amino acid point mutation in OCR-2 that disrupts TRPV channel-mediated gene expression, but does not decrease channel function in chemosensory primary signal transduction, also restores grk-2 bitter taste avoidance. Thus, loss of GRK-2 function may lead to changes in gene expression, via OSM-9/OCR-2, to selectively alter the levels of signaling components that transduce or regulate bitter taste responses. Our results suggest a novel mechanism and multiple modality-specific pathways that sensory cells employ in response to aberrant signal transduction. PMID:20176974

  6. Caenorhabditis elegans TRPV Channels Function in a Modality-Specific Pathway to Regulate Response to Aberrant Sensory Signaling

    PubMed Central

    Ezak , Meredith J.; Hong , Elizabeth; Chaparro-Garcia , Angela; Ferkey , Denise M.

    2010-01-01

    Olfaction and some forms of taste (including bitter) are mediated by G protein-coupled signal transduction pathways. Olfactory and gustatory ligands bind to chemosensory G protein-coupled receptors (GPCRs) in specialized sensory cells to activate intracellular signal transduction cascades. G protein-coupled receptor kinases (GRKs) are negative regulators of signaling that specifically phosphorylate activated GPCRs to terminate signaling. Although loss of GRK function usually results in enhanced cellular signaling, Caenorhabditis elegans lacking GRK-2 function are not hypersensitive to chemosensory stimuli. Instead, grk-2 mutant animals do not chemotax toward attractive olfactory stimuli or avoid aversive tastes and smells. We show here that loss-of-function mutations in the transient receptor potential vanilloid (TRPV) channels OSM-9 and OCR-2 selectively restore grk-2 behavioral avoidance of bitter tastants, revealing modality-specific mechanisms for TRPV channel function in the regulation of C. elegans chemosensation. Additionally, a single amino acid point mutation in OCR-2 that disrupts TRPV channel-mediated gene expression, but does not decrease channel function in chemosensory primary signal transduction, also restores grk-2 bitter taste avoidance. Thus, loss of GRK-2 function may lead to changes in gene expression, via OSM-9/OCR-2, to selectively alter the levels of signaling components that transduce or regulate bitter taste responses. Our results suggest a novel mechanism and multiple modality-specific pathways that sensory cells employ in response to aberrant signal transduction. PMID:20176974

  7. Electron/muon specific two Higgs doublet model at e+e- colliders

    NASA Astrophysics Data System (ADS)

    Johansen, Aria R.; Sher, Marc

    2015-03-01

    Recently, Kajiyama, Okada and Yagyu proposed an electron/muon specific two Higgs doublet model. In this model, an S3 symmetry suppresses flavor-changing neutral currents instead of a Z2 symmetry. In the "Type I" version of the model, the heavy Higgs bosons have a greatly enhanced coupling to electrons and muons. Kajiyama, Okada and Yagyu studied the phenomenology of the heavy Higgs bosons at the LHC. In this paper, the phenomenology at electron-positron colliders is studied. For the heavy Higgs mass range between 150 and 210 GeV, bounds from Large Electron Positron (LEP-200) Collider are stronger than those from the LHC. The model allows for the interesting possibility that muon pair production at the International Linear Collider can be mediated by s-channel Higgs exchange. This requires an energy scan. The scanning rate and necessary resolution are discussed.

  8. Smad2 and Smad3 have differential sensitivity in relaying TGFβ signaling and inversely regulate early lineage specification

    PubMed Central

    Liu, Ling; Liu, Xu; Ren, Xudong; Tian, Yue; Chen, Zhenyu; Xu, Xiangjie; Du, Yanhua; Jiang, Cizhong; Fang, Yujiang; Liu, Zhongliang; Fan, Beibei; Zhang, Quanbin; Jin, Guohua; Yang, Xiao; Zhang, Xiaoqing

    2016-01-01

    The transforming growth factor beta (TGFβ) related signaling is one of the most important signaling pathways regulating early developmental events. Smad2 and Smad3 are structurally similar and it is mostly considered that they are equally important in mediating TGFβ signals. Here, we show that Smad3 is an insensitive TGFβ transducer as compared with Smad2. Smad3 preferentially localizes within the nucleus and is thus sequestered from membrane signaling. The ability of Smad3 in oligomerization with Smad4 upon agonist stimulation is also impaired given its unique linker region. Smad2 mediated TGFβ signaling plays a crucial role in epiblast development and patterning of three germ layers. However, signaling unrelated nuclear localized Smad3 is dispensable for TGFβ signaling-mediated epiblast specification, but important for early neural development, an event blocked by TGFβ/Smad2 signaling. Both Smad2 and Smad3 bind to the conserved Smads binding element (SBE), but they show nonoverlapped target gene binding specificity and differential transcriptional activity. We conclude that Smad2 and Smad3 possess differential sensitivities in relaying TGFβ signaling and have distinct roles in regulating early developmental events. PMID:26905010

  9. Capturing structured, pulmonary disease-specific data elements in electronic health records.

    PubMed

    Gabriel, Peter E; Gronkiewicz, Cynthia; Diamond, Edward J; French, Kim D; Christodouleas, John

    2015-04-01

    Electronic health records (EHRs) have the potential to improve health-care quality by allowing providers to make better decisions at the point of care based on electronically aggregated data and by facilitating clinical research. These goals are easier to achieve when key, disease-specific clinical information is documented as structured data elements (SDEs) that computers can understand and process, rather than as free-text/natural-language narrative. This article reviews the benefits of capturing disease-specific SDEs. It highlights several design and implementation considerations, including the impact on efficiency and expressivity of clinical documentation and the importance of adhering to data standards when available. Pulmonary disease-specific examples of collection instruments are provided from two commonly used commercial EHRs. Future developments that can leverage SDEs to improve clinical quality and research are discussed. PMID:25846531

  10. Design and development of detector signal conditioning electronics for SST-1 Thomson scattering system.

    PubMed

    Thakar, Aruna; Kumar, Ajai; Thomas, Jinto; Chavda, Chhaya

    2008-09-01

    An IR enhanced thermoelectrically cooled Si-avalanche photodiode (Si-APD) module is used for detection of scattered photons from plasma electrons. Present design of signal conditioning electronics for the APD has fast (50 MHz) and slow (500 kHz) channels to measure scattered and plasma background light, respectively. We report design analysis for different stages and their performance. The performance of fast channel is analyzed for two different group delays, speed, linearity, and its cross-talk with slow channel. Temperature dependence of APD's responsivity is studied in the wavelength range of 900-1060 nm. A minimum detection of approximately 25 photoelectrons (with SN=1) in the range of 5 to 25 degrees C is achieved at an APD gain of 75 in the present design.

  11. Joint analysis of band-specific functional connectivity and signal complexity in autism.

    PubMed

    Ghanbari, Yasser; Bloy, Luke; Christopher Edgar, J; Blaskey, Lisa; Verma, Ragini; Roberts, Timothy P L

    2015-02-01

    Examination of resting state brain activity using electrophysiological measures like complexity as well as functional connectivity is of growing interest in the study of autism spectrum disorders (ASD). The present paper jointly examined complexity and connectivity to obtain a more detailed characterization of resting state brain activity in ASD. Multi-scale entropy was computed to quantify the signal complexity, and synchronization likelihood was used to evaluate functional connectivity (FC), with node strength values providing a sensor-level measure of connectivity to facilitate comparisons with complexity. Sensor level analysis of complexity and connectivity was performed at different frequency bands computed from resting state MEG from 26 children with ASD and 22 typically developing controls (TD). Analyses revealed band-specific group differences in each measure that agreed with other functional studies in fMRI and EEG: higher complexity in TD than ASD, in frontal regions in the delta band and occipital-parietal regions in the alpha band, and lower complexity in TD than in ASD in delta (parietal regions), theta (central and temporal regions) and gamma (frontal-central boundary regions); increased short-range connectivity in ASD in the frontal lobe in the delta band and long-range connectivity in the temporal, parietal and occipital lobes in the alpha band. Finally, and perhaps most strikingly, group differences between ASD and TD in complexity and FC appear spatially complementary, such that where FC was elevated in ASD, complexity was reduced (and vice versa). The correlation of regional average complexity and connectivity node strength with symptom severity scores of ASD subjects supported the overall complementarity (with opposing sign) of connectivity and complexity measures, pointing to either diminished connectivity leading to elevated entropy due to poor inhibitory regulation or chaotic signals prohibiting effective measure of connectivity.

  12. Joint Analysis of Band-Specific Functional Connectivity and Signal Complexity in Autism

    PubMed Central

    Ghanbari, Yasser; Bloy, Luke; Edgar, J. Christopher; Blaskey, Lisa; Verma, Ragini

    2013-01-01

    Examination of resting state brain activity using electrophysiological measures like complexity as well as functional connectivity is of growing interest in the study of autism spectrum disorders (ASD). The present paper jointly examined complexity and connectivity to obtain a more detailed characterization of resting state brain activity in ASD. Multi-scale entropy was computed to quantify the signal complexity, and synchronization likelihood was used to evaluate functional connectivity (FC), with node strength values providing a sensor-level measure of connectivity to facilitate comparisons with complexity. Sensor level analysis of complexity and connectivity was performed at different frequency bands computed from resting state MEG from 26 children with ASD and 22 typically developing controls (TD). Analyses revealed band-specific group differences in each measure that agreed with other functional studies in fMRI and EEG: higher complexity in TD than ASD, in frontal regions in the delta band and occipital-parietal regions in the alpha band, and lower complexity in TD than in ASD in delta (parietal regions), theta (central and temporal regions) and gamma (frontal-central boundary regions); increased short-range connectivity in ASD in the frontal lobe in the delta band and long-range connectivity in the temporal, parietal and occipital lobes in the alpha band. Finally, and perhaps most strikingly, group differences between ASD and TD in complexity and FC appear spatially complementary, such that where FC was elevated in ASD, complexity was reduced (and vice versa). The correlation of regional average complexity and connectivity node strength with symptom severity scores of ASD subjects supported the overall complementarity (with opposing sign) of connectivity and complexity measures, pointing to either diminished connectivity leading to elevated entropy due to poor inhibitory regulation or chaotic signals prohibiting effective measure of connectivity. PMID

  13. Measuring the Electronic Properties of DNA-Specific Schottky Diodes Towards Detecting and Identifying Basidiomycetes DNA

    NASA Astrophysics Data System (ADS)

    Periasamy, Vengadesh; Rizan, Nastaran; Al-Ta’Ii, Hassan Maktuff Jaber; Tan, Yee Shin; Tajuddin, Hairul Annuar; Iwamoto, Mitsumasa

    2016-07-01

    The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large number of literatures in the study of DNA electronics. Sequence-specific electronic response provides a platform towards understanding charge transfer mechanism and therefore the electronic properties of DNA. It is possible to utilize these characteristic properties to identify/detect DNA. In this current work, we demonstrate a novel method of DNA-based identification of basidiomycetes using current-voltage (I-V) profiles obtained from DNA-specific Schottky barrier diodes. Electronic properties such as ideality factor, barrier height, shunt resistance, series resistance, turn-on voltage, knee-voltage, breakdown voltage and breakdown current were calculated and used to quantify the identification process as compared to morphological and molecular characterization techniques. The use of these techniques is necessary in order to study biodiversity, but sometimes it can be misleading and unreliable and is not sufficiently useful for the identification of fungi genera. Many of these methods have failed when it comes to identification of closely related species of certain genus like Pleurotus. Our electronics profiles, both in the negative and positive bias regions were however found to be highly characteristic according to the base-pair sequences. We believe that this simple, low-cost and practical method could be useful towards identifying and detecting DNA in biotechnology and pathology.

  14. Measuring the Electronic Properties of DNA-Specific Schottky Diodes Towards Detecting and Identifying Basidiomycetes DNA

    PubMed Central

    Periasamy, Vengadesh; Rizan, Nastaran; Al-Ta’ii, Hassan Maktuff Jaber; Tan, Yee Shin; Tajuddin, Hairul Annuar; Iwamoto, Mitsumasa

    2016-01-01

    The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large number of literatures in the study of DNA electronics. Sequence-specific electronic response provides a platform towards understanding charge transfer mechanism and therefore the electronic properties of DNA. It is possible to utilize these characteristic properties to identify/detect DNA. In this current work, we demonstrate a novel method of DNA-based identification of basidiomycetes using current-voltage (I-V) profiles obtained from DNA-specific Schottky barrier diodes. Electronic properties such as ideality factor, barrier height, shunt resistance, series resistance, turn-on voltage, knee-voltage, breakdown voltage and breakdown current were calculated and used to quantify the identification process as compared to morphological and molecular characterization techniques. The use of these techniques is necessary in order to study biodiversity, but sometimes it can be misleading and unreliable and is not sufficiently useful for the identification of fungi genera. Many of these methods have failed when it comes to identification of closely related species of certain genus like Pleurotus. Our electronics profiles, both in the negative and positive bias regions were however found to be highly characteristic according to the base-pair sequences. We believe that this simple, low-cost and practical method could be useful towards identifying and detecting DNA in biotechnology and pathology. PMID:27435636

  15. Yeast cell wall integrity sensors form specific plasma membrane microdomains important for signalling.

    PubMed

    Kock, Christian; Arlt, Henning; Ungermann, Christian; Heinisch, Jürgen J

    2016-09-01

    The cell wall integrity (CWI) pathway of the yeast Saccharomyces cerevisiae relies on the detection of cell surface stress by five sensors (Wsc1, Wsc2, Wsc3, Mid2, Mtl1). Each sensor contains a single transmembrane domain and a highly mannosylated extracellular region, and probably detects mechanical stress in the cell wall or the plasma membrane. We here studied the distribution of the five sensors at the cell surface by using fluorescently tagged variants in conjunction with marker proteins for established membrane compartments. We find that each of the sensors occupies a specific microdomain at the plasma membrane. The novel punctate 'membrane compartment occupied by Wsc1' (MCW) shows moderate overlap with other Wsc-type sensors, but not with those of the Mid-type sensors or other established plasma membrane domains. We further observed that sensor density and formation of the MCW compartment depends on the cysteine-rich head group near the N-terminus of Wsc1. Yet, signalling capacity depends more on the sensor density in the plasma membrane than on clustering within its microcompartment. We propose that the MCW microcompartment provides a quality control mechanism for retaining functional sensors at the plasma membrane to prevent them from endocytosis.

  16. Detection of Q Fever Specific Antibodies Using Recombinant Antigen in ELISA with Peroxidase Based Signal Amplification

    PubMed Central

    Chen, Hua-Wei; Zhang, Zhiwen; Glennon, Erin; Ching, Wei-Mei

    2014-01-01

    Currently, the accepted method for Q fever serodiagnosis is indirect immunofluorescent antibody assay (IFA) using the whole cell antigen. In this study, we prepared the recombinant antigen of the 27-kDa outer membrane protein (Com1) which has been shown to be recognized by Q fever patient sera. The performance of recombinant Com1 was evaluated in ELISA by IFA confirmed serum samples. Due to the low titers of IgG and IgM in Q fever patients, the standard ELISA signals were further amplified by using biotinylated anti-human IgG or IgM plus streptavidin-HRP polymer. The modified ELISA can detect 88% (29 out of 33) of Q fever patient sera collected from Marines deployed to Iraq. Less than 5% (5 out of 156) of the sera from patients with other febrile diseases reacted with the Com1. These results suggest that the modified ELISA using Com1 may have the potential to improve the detection of Q fever specific antibodies. PMID:26904739

  17. Speaker specificity in speech perception: the importance of what is and is not in the signal

    NASA Astrophysics Data System (ADS)

    Dahan, Delphine; Scarborough, Rebecca A.

    2005-09-01

    In some American English dialects, /ae/ before /g/ (but not before /k/) raises to a vowel approaching [E], in effect reducing phonetic overlap between (e.g.) ``bag'' and ``back.'' Here, participants saw four written words on a computer screen (e.g., ``bag,'' ``back,'' ``dog,'' ``dock'') and heard a spoken word. Their task was to indicate which word they heard. Participants' eye movements to the written words were recorded. Participants in the ``ae-raising'' group heard identity-spliced ``bag''-like words containing the raised vowel [E] participants in the ``control'' group heard cross-spliced ``bag''-like words containing standard [ae]. Acoustically identical ``back''-like words were subsequently presented to both groups. The ae-raising-group participants identified ``back''-like words faster and more accurately, and made fewer fixations to the competitor ``bag,'' than control-group participants did. Thus, exposure to ae-raised realizations of ``bag'' facilitated the identification of ``back'' because of the reduced fit between the input and the altered representation of the competing hypothesis ``bag.'' This demonstrates that listeners evaluate the spoken input with respect to what is, but also what is not, in the signal, and that this evaluation involves speaker-specific representations. [Work supported by NSF Human and Social Dynamics 0433567.

  18. Paired receptor specificity explained by structures of signal regulatory proteins alone and complexed with CD47.

    PubMed

    Hatherley, Deborah; Graham, Stephen C; Turner, Jessie; Harlos, Karl; Stuart, David I; Barclay, A Neil

    2008-07-25

    CD47 is a widely distributed cell-surface protein that acts a marker of self through interactions of myeloid and neural cells. We describe the high-resolution X-ray crystallographic structures of the immunoglobulin superfamily domain of CD47 alone and in complex with the N-terminal ligand-binding domain of signal regulatory protein alpha (SIRPalpha). The unusual and convoluted interacting face of CD47, comprising the N terminus and loops at the end of the domain, intercalates with the corresponding regions in SIRPalpha. We have also determined structures of the N-terminal domains of SIRPbeta, SIRPbeta(2), and SIRPgamma; proteins that are closely related to SIRPalpha but bind CD47 with negligible or reduced affinity. These results explain the specificity of CD47 for the SIRP family of paired receptors in atomic detail. Analysis of SIRPalpha polymorphisms suggests that these, as well as the activating SIRPs, may have evolved to counteract pathogen binding to the inhibitory SIRPalpha receptor.

  19. Microarray analysis of the AHR system: Tissue-specific flexibility in signal and target genes

    SciTech Connect

    Frericks, Markus; Meissner, Marc; Esser, Charlotte . E-mail: chesser@uni-duesseldorf.de

    2007-05-01

    Data mining published microarray experiments require that expression profiles are directly comparable. We performed linear global normalization on the data of 1967 Affymetrix U74av2 microarrays, i.e. the transcriptomes of > 100 murine tissues or cell types. The mathematical transformation effectively nullifies inter-experimental or inter-laboratory differences between microarrays. The correctness of expression values was validated by quantitative RT-PCR. Using the database we analyze components of the aryl hydrocarbon receptor (AHR) signaling pathway in various tissues. We identified lineage and differentiation specific variant expression of AHR, ARNT, and HIF1{alpha} in the T-cell lineage and high expression of CYP1A1 in immature B cells and dendritic cells. Performing co-expression analysis we found unorthodox expression of the AHR in the absence of ARNT, particularly in stem cell populations, and can reject the hypothesis that ARNT2 takes over and is highly expressed when ARNT expression is low or absent. Furthermore the AHR shows no co-expression with any other transcript present on the chip. Analysis of differential gene expression under 308 conditions revealed 53 conditions under which the AHR is regulated, numerous conditions under which an intrinsic AHR action is modified as well as conditions activating the AHR even in the absence of known AHR ligands. Thus meta-analysis of published expression profiles is a powerful tool to gain novel insights into known and unknown systems.

  20. SUBTYPE-SPECIFIC REGENERATION OF RETINAL GANGLION CELLS FOLLOWING AXOTOMY: EFFECTS OF OSTEOPONTIN AND MTOR SIGNALING

    PubMed Central

    Duan, Xin; Qiao, Mu; Bei, Fengfeng; Kim, In-Jung; He, Zhigang; Sanes, Joshua R.

    2015-01-01

    SUMMARY In mammals, few retinal ganglion cells (RGCs) survive following axotomy and even fewer regenerate axons. This could reflect differential extrinsic influences or the existence of subpopulations that vary in their responses to injury. We tested these alternatives by comparing responses of molecularly distinct subsets of mouse RGCs to axotomy. Survival rates varied dramatically among subtypes, with alpha-RGCs (αRGCs) surviving preferentially. Among survivors, αRGCs accounted for nearly all regeneration following down-regulation of PTEN, which activates the mTOR pathway. αRGCs have uniquely high mTOR signaling levels among RGCs and also selectively express osteopontin (OPN) and receptors for the growth factor, insulin-like growth factor 1 (IGF-1). Administration of OPN plus IGF-1 promotes regeneration as effectively as down-regulation of PTEN; however, regeneration is still confined to αRGCs. Our results reveal dramatic subtype-specific differences in the ability of RGCs to survive and regenerate following injury, and they identify promising agents for promoting axonal regeneration. PMID:25754821

  1. Core Community Specifications for Electron Microprobe Operating Systems: Software, Quality Control, and Data Management Issues

    NASA Technical Reports Server (NTRS)

    Fournelle, John; Carpenter, Paul

    2006-01-01

    Modem electron microprobe systems have become increasingly sophisticated. These systems utilize either UNIX or PC computer systems for measurement, automation, and data reduction. These systems have undergone major improvements in processing, storage, display, and communications, due to increased capabilities of hardware and software. Instrument specifications are typically utilized at the time of purchase and concentrate on hardware performance. The microanalysis community includes analysts, researchers, software developers, and manufacturers, who could benefit from exchange of ideas and the ultimate development of core community specifications (CCS) for hardware and software components of microprobe instrumentation and operating systems.

  2. Retinol as electron carrier in redox signaling, a new frontier in vitamin A research

    PubMed Central

    2016-01-01

    Nature uses carotenoids and retinoids as chromophores for diverse energy conversion processes. The key structural feature enabling the interaction with light and other manifestations of electro-magnetism is the conjugated double-bond system that all members of this superfamily share in common. Among retinoids, retinaldehyde alone was long known as the active chromophore of vision in vertebrates and invertebrates, as well of various light-driven proton and ion pumps in Archaea. Until now, vitamin A (retinol) was solely regarded as a biochemical precursor for bioactive retinoids such as retinaldehyde and retinoic acid (RA), but recent results indicate that this compound has its own physiology. It functions as an electron carrier in mitochondria. By electronically coupling protein kinase Cδ (PCKδ) with cytochrome c, vitamin A enables the redox activation of this enzyme. This review focuses on the biochemistry and biology of the PCKδ signaling system, comprising PKCδ, the adapter protein p66Shc, cytochrome c and retinol. This complex positively regulates the conversion of pyruvate to acetyl-coenzyme A (CoA) by the pyruvate dehydrogenase enzyme. Vitamin A therefore plays a key role in glycolytic energy generation. The emerging paradigm of retinol as electron-transfer agent is potentially transformative, opening new frontiers in retinoid research. PMID:26904553

  3. Dark matter scattering on electrons: Accurate calculations of atomic excitations and implications for the DAMA signal

    NASA Astrophysics Data System (ADS)

    Roberts, B. M.; Dzuba, V. A.; Flambaum, V. V.; Pospelov, M.; Stadnik, Y. V.

    2016-06-01

    We revisit the WIMP-type dark matter scattering on electrons that results in atomic ionization and can manifest itself in a variety of existing direct-detection experiments. Unlike the WIMP-nucleon scattering, where current experiments probe typical interaction strengths much smaller than the Fermi constant, the scattering on electrons requires a much stronger interaction to be detectable, which in turn requires new light force carriers. We account for such new forces explicitly, by introducing a mediator particle with scalar or vector couplings to dark matter and to electrons. We then perform state-of-the-art numerical calculations of atomic ionization relevant to the existing experiments. Our goals are to consistently take into account the atomic physics aspect of the problem (e.g., the relativistic effects, which can be quite significant) and to scan the parameter space—the dark matter mass, the mediator mass, and the effective coupling strength—to see if there is any part of the parameter space that could potentially explain the DAMA modulation signal. While we find that the modulation fraction of all events with energy deposition above 2 keV in NaI can be quite significant, reaching ˜50 %, the relevant parts of the parameter space are excluded by the XENON10 and XENON100 experiments.

  4. Context Specificity of Stress-activated Mitogen-activated Protein (MAP) Kinase Signaling: The Story as Told by Caenorhabditis elegans.

    PubMed

    Andrusiak, Matthew G; Jin, Yishi

    2016-04-01

    Stress-associated p38 and JNK mitogen-activated protein (MAP) kinase signaling cascades trigger specific cellular responses and are involved in multiple disease states. At the root of MAP kinase signaling complexity is the differential use of common components on a context-specific basis. The roundwormCaenorhabditis eleganswas developed as a system to study genes required for development and nervous system function. The powerful genetics ofC. elegansin combination with molecular and cellular dissections has led to a greater understanding of how p38 and JNK signaling affects many biological processes under normal and stress conditions. This review focuses on the studies revealing context specificity of different stress-activated MAPK components inC. elegans.

  5. Context Specificity of Stress-activated Mitogen-activated Protein (MAP) Kinase Signaling: The Story as Told by Caenorhabditis elegans.

    PubMed

    Andrusiak, Matthew G; Jin, Yishi

    2016-04-01

    Stress-associated p38 and JNK mitogen-activated protein (MAP) kinase signaling cascades trigger specific cellular responses and are involved in multiple disease states. At the root of MAP kinase signaling complexity is the differential use of common components on a context-specific basis. The roundwormCaenorhabditis eleganswas developed as a system to study genes required for development and nervous system function. The powerful genetics ofC. elegansin combination with molecular and cellular dissections has led to a greater understanding of how p38 and JNK signaling affects many biological processes under normal and stress conditions. This review focuses on the studies revealing context specificity of different stress-activated MAPK components inC. elegans. PMID:26907690

  6. Average and worst-case specifications of precipitating auroral electron environment

    NASA Technical Reports Server (NTRS)

    Hardy, D. A.; Burke, W. J.; Gussenhoven, M. S.; Holeman, E.; Yeh, H. C.

    1985-01-01

    The precipitation electrons in the auroral environment are highly variable in their energy and intensity in both space and time. As such they are a source of potential hazard to the operation of the Space Shuttle and other large spacecraft operating in polar orbit. In order to assess these hazards both the average and extreme states of the precipitating electrons must be determined. Work aimed at such a specification is presented. First results of a global study of the average characteristics are presented. In this study the high latitude region was divided into spatial elements in magnetic local time and corrected geomagnetic latitude. The average electron spectrum was then determined in each spatial element for seven different levels of activity as measured by K sub p using an extremely large data set of auroral observations. Second a case study of an extreme auroral electron environment is presented, in which the electrons are accelerated through field aligned potential as high as 30,000 volts and in which the spacecraft is seen to charge negatively to a potential approaching .5 kilovolts.

  7. Signaling Pathways Involved in Striatal Synaptic Plasticity are Sensitive to Temporal Pattern and Exhibit Spatial Specificity

    PubMed Central

    Kim, BoHung; Hawes, Sarah L.; Gillani, Fawad; Wallace, Lane J.; Blackwell, Kim T.

    2013-01-01

    The basal ganglia is a brain region critically involved in reinforcement learning and motor control. Synaptic plasticity in the striatum of the basal ganglia is a cellular mechanism implicated in learning and neuronal information processing. Therefore, understanding how different spatio-temporal patterns of synaptic input select for different types of plasticity is key to understanding learning mechanisms. In striatal medium spiny projection neurons (MSPN), both long term potentiation (LTP) and long term depression (LTD) require an elevation in intracellular calcium concentration; however, it is unknown how the post-synaptic neuron discriminates between different patterns of calcium influx. Using computer modeling, we investigate the hypothesis that temporal pattern of stimulation can select for either endocannabinoid production (for LTD) or protein kinase C (PKC) activation (for LTP) in striatal MSPNs. We implement a stochastic model of the post-synaptic signaling pathways in a dendrite with one or more diffusionally coupled spines. The model is validated by comparison to experiments measuring endocannabinoid-dependent depolarization induced suppression of inhibition. Using the validated model, simulations demonstrate that theta burst stimulation, which produces LTP, increases the activation of PKC as compared to 20 Hz stimulation, which produces LTD. The model prediction that PKC activation is required for theta burst LTP is confirmed experimentally. Using the ratio of PKC to endocannabinoid production as an index of plasticity direction, model simulations demonstrate that LTP exhibits spine level spatial specificity, whereas LTD is more diffuse. These results suggest that spatio-temporal control of striatal information processing employs these Gq coupled pathways. PMID:23516346

  8. ROS/redox signaling regulates bone turnover in an age-specific manner in female mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In bone, oxidant signaling through NADPH oxidase (NOX)-derived reactive oxygen species (ROS) superoxide and/or hydrogen peroxide appears to be an important stimulus for osteoclast differentiation and activity. ROS signaling has been suggested to increase RANKL mRNA and protein expression, thus enha...

  9. An FGF3-BMP Signaling Axis Regulates Caudal Neural Tube Closure, Neural Crest Specification and Anterior-Posterior Axis Extension

    PubMed Central

    Anderson, Matthew J.; Schimmang, Thomas; Lewandoski, Mark

    2016-01-01

    During vertebrate axis extension, adjacent tissue layers undergo profound morphological changes: within the neuroepithelium, neural tube closure and neural crest formation are occurring, while within the paraxial mesoderm somites are segmenting from the presomitic mesoderm (PSM). Little is known about the signals between these tissues that regulate their coordinated morphogenesis. Here, we analyze the posterior axis truncation of mouse Fgf3 null homozygotes and demonstrate that the earliest role of PSM-derived FGF3 is to regulate BMP signals in the adjacent neuroepithelium. FGF3 loss causes elevated BMP signals leading to increased neuroepithelium proliferation, delay in neural tube closure and premature neural crest specification. We demonstrate that elevated BMP4 depletes PSM progenitors in vitro, phenocopying the Fgf3 mutant, suggesting that excessive BMP signals cause the Fgf3 axis defect. To test this in vivo we increased BMP signaling in Fgf3 mutants by removing one copy of Noggin, which encodes a BMP antagonist. In such mutants, all parameters of the Fgf3 phenotype were exacerbated: neural tube closure delay, premature neural crest specification, and premature axis termination. Conversely, genetically decreasing BMP signaling in Fgf3 mutants, via loss of BMP receptor activity, alleviates morphological defects. Aberrant apoptosis is observed in the Fgf3 mutant tailbud. However, we demonstrate that cell death does not cause the Fgf3 phenotype: blocking apoptosis via deletion of pro-apoptotic genes surprisingly increases all Fgf3 defects including causing spina bifida. We demonstrate that this counterintuitive consequence of blocking apoptosis is caused by the increased survival of BMP-producing cells in the neuroepithelium. Thus, we show that FGF3 in the caudal vertebrate embryo regulates BMP signaling in the neuroepithelium, which in turn regulates neural tube closure, neural crest specification and axis termination. Uncovering this FGF3-BMP signaling axis is

  10. THE SPECIFIC ACCELERATION RATE IN LOOP-STRUCTURED SOLAR FLARES-IMPLICATIONS FOR ELECTRON ACCELERATION MODELS

    SciTech Connect

    Guo, Jingnan; Emslie, A. Gordon; Piana, Michele E-mail: piana@dima.unige.it

    2013-03-20

    We analyze electron flux maps based on RHESSI hard X-ray imaging spectroscopy data for a number of extended coronal-loop flare events. For each event, we determine the variation of the characteristic loop length L with electron energy E, and we fit this observed behavior with models that incorporate an extended acceleration region and an exterior 'propagation' region, and which may include collisional modification of the accelerated electron spectrum inside the acceleration region. The models are characterized by two parameters: the plasma density n in, and the longitudinal extent L{sub 0} of, the acceleration region. Determination of the best-fit values of these parameters permits inference of the volume that encompasses the acceleration region and of the total number of particles within it. It is then straightforward to compute values for the emission filling factor and for the specific acceleration rate (electrons s{sup -1} per ambient electron above a chosen reference energy). For the 24 events studied, the range of inferred filling factors is consistent with a value of unity. The inferred mean value of the specific acceleration rate above E{sub 0} = 20 keV is {approx}10{sup -2} s{sup -1}, with a 1{sigma} spread of about a half-order-of-magnitude above and below this value. We compare these values with the predictions of several models, including acceleration by large-scale, weak (sub-Dreicer) fields, by strong (super-Dreicer) electric fields in a reconnecting current sheet, and by stochastic acceleration processes.

  11. Random telegraph signals by alkanethiol-protected Au nanoparticles in chemically assembled single-electron transistors

    SciTech Connect

    Kano, Shinya; Azuma, Yasuo; Tanaka, Daisuke; Sakamoto, Masanori; Teranishi, Toshiharu; Smith, Luke W.; Smith, Charles G.; Majima, Yutaka

    2013-12-14

    We have studied random telegraph signals (RTSs) in a chemically assembled single-electron transistor (SET) at temperatures as low as 300 mK. The RTSs in the chemically assembled SET were investigated by measuring the source–drain current, using a histogram of the RTS dwell time, and calculating the power spectrum density of the drain current–time characteristics. It was found that the dwell time of the RTS was dependent on the drain voltage of the SET, but was independent of the gate voltage. Considering the spatial structure of the chemically assembled SET, the origin of the RTS is attributed to the trapped charges on an alkanethiol-protected Au nanoparticle positioned near the SET. These results are important as they will help to realize stable chemically assembled SETs in practical applications.

  12. A Probabilistic Boolean Network Approach for the Analysis of Cancer-Specific Signalling: A Case Study of Deregulated PDGF Signalling in GIST

    PubMed Central

    Wiesinger, Monique; Bahlawane, Christelle; Haan, Serge; Sauter, Thomas

    2016-01-01

    Background Signal transduction networks are increasingly studied with mathematical modelling approaches while each of them is suited for a particular problem. For the contextualisation and analysis of signalling networks with steady-state protein data, we identified probabilistic Boolean network (PBN) as a promising framework which could capture quantitative changes of molecular changes at steady-state with a minimal parameterisation. Results and Conclusion In our case study, we successfully applied the PBN approach to model and analyse the deregulated Platelet-Derived Growth Factor (PDGF) signalling pathway in Gastrointestinal Stromal Tumour (GIST). We experimentally determined a rich and accurate dataset of steady-state profiles of selected downstream kinases of PDGF-receptor-alpha mutants in combination with inhibitor treatments. Applying the tool optPBN, we fitted a literature-derived candidate network model to the training dataset consisting of single perturbation conditions. Model analysis suggested several important crosstalk interactions. The validity of these predictions was further investigated experimentally pointing to relevant ongoing crosstalk from PI3K to MAPK signalling in tumour cells. The refined model was evaluated with a validation dataset comprising multiple perturbation conditions. The model thereby showed excellent performance allowing to quantitatively predict the combinatorial responses from the individual treatment results in this cancer setting. The established optPBN pipeline is also widely applicable to gain a better understanding of other signalling networks at steady-state in a context-specific fashion. PMID:27232499

  13. Intracellular calcium signals regulate growth of hepatic stellate cells via specific effects on cell cycle progression

    PubMed Central

    Soliman, Elwy M.; Rodrigues, Michele Angela; Gomes, Dawidson Assis; Sheung, Nina; Yu, Jin; Amaya, Maria Jimina; Nathanson, Michael H.; Dranoff, Jonathan A.

    2010-01-01

    Hepatic stellate cells (HSC) are important mediators of liver fibrosis. Hormones linked to downstream intracellular Ca2+ signals upregulate HSC proliferation, but the mechanisms by which this occurs are unknown. Nuclear and cytosolic Ca2+ signals may have distinct effects on cell proliferation, so we expressed plasmid and adenoviral constructs containing the Ca2+ chelator parvalbumin (PV) linked to either a nuclear localization sequence (NLS) or a nuclear export sequence (NES) to block Ca2+ signals in distinct compartments within LX-2 immortalized human HSC and primary rat HSC. PV-NLS and PV-NES constructs each targeted to the appropriate intracellular compartment and blocked Ca2+ signals only within that compartment. PV-NLS and PV-NES constructs inhibited HSC growth. Furthermore, blockade of nuclear or cytosolic Ca2+ signals arrested growth at the G2/mitosis (G2/M) cell-cycle interface and prevented the onset of mitosis. Blockade of nuclear or cytosolic Ca2+ signals downregulated phosphorylation of the G2/M checkpoint phosphatase Cdc25C. Inhibition of calmodulin kinase II (CaMK II) had identical effects on LX-2 growth and Cdc25C phosphorylation. We propose that nuclear and cytosolic Ca2+ are critical signals that regulate HSC growth at the G2/M checkpoint via CaMK II-mediated regulation of Cdc25C phosphorylation. These data provide a new logical target for pharmacological therapy directed against progression of liver fibrosis. PMID:19131107

  14. Precision analog signal processor for beam position measurements in electron storage rings

    SciTech Connect

    Hinkson, J.A.; Unser, K.B.

    1995-05-01

    Beam position monitors (BPM) in electron and positron storage rings have evolved from simple systems composed of beam pickups, coaxial cables, multiplexing relays, and a single receiver (usually a analyzer) into very complex and costly systems of multiple receivers and processors. The older may have taken minutes to measure the circulating beam closed orbit. Today instrumentation designers are required to provide high-speed measurements of the beam orbit, often at the ring revolution frequency. In addition the instruments must have very high accuracy and resolution. A BPM has been developed for the Advanced Light Source (ALS) in Berkeley which features high resolution and relatively low cost. The instrument has a single purpose; to measure position of a stable stored beam. Because the pickup signals are multiplexed into a single receiver, and due to its narrow bandwidth, the receiver is not intended for single-turn studies. The receiver delivers normalized measurements of X and Y posit ion entirely by analog means at nominally 1 V/mm. No computers are involved. No software is required. Bergoz, a French company specializing in precision beam instrumentation, integrated the ALS design m their new BPM analog signal processor module. Performance comparisons were made on the ALS. In this paper we report on the architecture and performance of the ALS prototype BPM.

  15. Specificity of RGS10A as a key component in the RANKL signaling mechanism for osteoclast differentiation

    PubMed Central

    Yang, Shuying; Chen, Wei; Stashenko, Philip; Li, Yi-Ping

    2013-01-01

    Summary Significant progress has been made in studies of the mechanisms by which RANKL induces terminal osteoclast differentiation. However, many crucial details in the RANKL-evoked signaling pathway for osteoclast differentiation remain to be defined. We characterized genes specifically expressed in osteoclasts by differential screening of a human osteoclastoma cDNA library, and found that the regulator of G-protein signaling 10A (RGS10A), but not the RGS10B isoform, was specifically expressed in human osteoclasts. The expression of RGS10A is also induced by RANKL in osteoclast precursors and is prominently expressed in mouse osteoclast-like cells. RGS10A silencing by RNA interference blocked intracellular [Ca2+]i oscillations, the expression of NFAT2, and osteoclast terminal differentiation in both bone marrow cells and osteoclast precursor cell lines. Reintroduction of RGS10A rescued the impaired osteoclast differentiation. RGS10A silencing also resulted in premature osteoclast apoptosis. RGS10A silencing affected the RANKL-[Ca2+]i oscillation-NFAT2 signaling pathway but not other RANKL-induced responses. Our data demonstrate that target components of RGS10A are distinct from those of RGS12 in the RANKL signaling mechanism. Our results thus show the specificity of RGS10A as a key component in the RANKL-evoked signaling pathway for osteoclast differentiation, which may present a promising target for therapeutic intervention. PMID:17881498

  16. AGE-RAGE signal generates a specific NF-κB RelA "barcode" that directs collagen I expression.

    PubMed

    Peng, Yunqian; Kim, Ji-Min; Park, Hal-Sol; Yang, Annie; Islam, Celia; Lakatta, Edward G; Lin, Li

    2016-01-01

    Advanced glycation end products (AGEs) are sugar-modified biomolecules that accumulate in the body with advancing age, and are implicated in the development of multiple age-associated structural and functional abnormities and diseases. It has been well documented that AGEs signal via their receptor RAGE to activate several cellular programs including NF-κB, leading to inflammation. A large number of stimuli can activate NF-κB; yet different stimuli, or the same stimulus for NF-κB in different cellular settings, produce a very different transcriptional landscape and physiological outcome. The NF-κB barcode hypothesis posits that cellular network dynamics generate signal-specific post-translational modifications, or a "barcode" to NF-κB, and that a signature "barcode" mediates a specific gene expression pattern. In the current study, we established that AGE-RAGE signaling results in NF-κB activation that directs collagen Ia1 and Ia2 expression. We further demonstrated that AGE-RAGE signal induces phosphorylation of RelA at three specific residues, T254, S311, and S536. These modifications are required for transcription of collagen I genes and are a consequence of cellular network dynamics. The increase of collagen content is a hallmark of arterial aging, and our work provides a potential mechanistic link between RAGE signaling, NF-κB activation, and aging-associated arterial alterations in structure and function. PMID:26729520

  17. Myeloid-Specific Blockade of Notch Signaling Attenuates Choroidal Neovascularization through Compromised Macrophage Infiltration and Polarization in Mice

    PubMed Central

    Dou, Guo-Rui; Li, Na; Chang, Tian-Fang; Zhang, Ping; Gao, Xiang; Yan, Xian-Chun; Liang, Liang; Han, Hua; Wang, Yu-Sheng

    2016-01-01

    Macrophages have been recognized as an important inflammatory component in choroidal neovascularization (CNV). However, it is unclear how these cells are activated and polarized, how they affect angiogenesis and what the underlining mechanisms are during CNV. Notch signaling has been implicated in macrophage activation. Previously we have shown that inducible disruption of RBP-J, the critical transcription factor of Notch signaling, in adult mice results in enhanced CNV, but it is unclear what is the role of macrophage-specific Notch signaling in the development of CNV. In the current study, by using the myeloid specific RBP-J knockout mouse model combined with the laser-induced CNV model, we show that disruption of Notch signaling in macrophages displayed attenuated CNV growth, reduced macrophage infiltration and activation, and alleviated angiogenic response after laser induction. The inhibition of CNV occurred with reduced expression of VEGF and TNF-α in infiltrating inflammatory macrophages in myeloid specific RBP-J knockout mice. These changes might result in direct inhibition of EC lumen formation, as shown in an in vitro study. Therefore, clinical intervention of Notch signaling in CNV needs to pinpoint myeloid lineage to avoid the counteractive effects of global inhibition. PMID:27339903

  18. Specific signal processing method for sound detected by an intrinsic optical fiber sensor

    NASA Astrophysics Data System (ADS)

    Arezki, M.; Meyrueis, P.; Javahiraly, N.

    2010-04-01

    Intrinsic optical fiber microphones with the design that we propose have a good sensitivity and dynamic allowing them to address many innovative applications. But their performances induce some defects as noise sensing that has to be separated to the wanted sound signal to obtain a clean usable sound signal. In this paper we introduce the design of an optical fiber sound sensing system and the bases of the adapted signal processing allowing to use all the advantages of this design with a low level of noise. The results are very promising.

  19. A hypothesis-effect of T cell epitope fusion peptide specific immunotherapy on signal transduction

    PubMed Central

    Li, Chao-Pin; Yang, Bang-He

    2015-01-01

    Asthma is a chronic nonspecific inflammatory disease of the airway primarily mediated by different inflammatory cells, including mast cells, eosinophils and T cells. We hereby specially focused on a signal pathway for Janus kinase-signal transducer and activators of transduction (JAK-STATs), which has been the interest of study in asthma since it more likely regulates cellular proliferation and differentiation, and consequently modulates immune system. In our consideration, knowledge on this signal pathway may provide an avenue for rational options in treatment of asthma on control of immune response basis. PMID:26770626

  20. Signal acquisition in Cherenkov-type diagnostics of electron beams within tokamak facilities

    NASA Astrophysics Data System (ADS)

    Rabiński, Marek; Jakubowski, Lech; Sadowski, Marek J.; Żebrowski, Jarosław; Jakubowski, Marcin J.; Malinowski, Karol; Mirowski, Robert

    2015-09-01

    The paper presents feasibility and design studies of Cherenkov-type probes, a development of the measuring head construction designed for different tokamak devices, and in particular the acquisition of optical signals to a data storage system. In order to lower the energy threshold of the electron detection the authors applied radiators with the highest values of the refractive index. Different radiator materials, such as aluminium nitride and CVD diamond were applied. Several versions of measuring heads and different manipulators, e.g., a movable vacuum-tight shaft or a fast-moving reciprocating probe, were manufactured and used. The practical application of the Cherenkov probes required also a consideration of spectral characteristics of optical fibres and photomultipliers. The Cherenkov radiation, as generated inside the radiators, is lead out through separate fibres (optical cables) to the atmospheric pressure side. The emitted radiation in the blue (near ultraviolet) spectrum range should be collected and delivered through appropriate optical cables to a control room, amplified within photomultipliers and recorded in a digital form. In order to investigate an electron energy distribution the multi-channel probes have also been designed and applied.

  1. Distribution and specificity of S-cone ("blue cone") signals in subcortical visual pathways.

    PubMed

    Martin, Paul R; Lee, Barry B

    2014-03-01

    We review here the distribution of S-cone signals and properties of S-cone recipient receptive fields in subcortical pathways. Nearly everything we know about S-cone signals in the subcortical visual system comes from the study of visual systems in cats and primates (monkeys); in this review, we concentrate on results from macaque and marmoset monkeys. We discuss segregation of S-cone recipient (blue-on and blue-off) receptive fields in the dorsal lateral geniculate nucleus and describe their receptive field properties. We treat in some detail the question of detecting weak S-cone signals as an introduction for newcomers to the field. Finally, we briefly consider the question on how S-cone signals are distributed among nongeniculate targets. PMID:24555883

  2. Distribution and specificity of S-cone ("blue cone") signals in subcortical visual pathways.

    PubMed

    Martin, Paul R; Lee, Barry B

    2014-03-01

    We review here the distribution of S-cone signals and properties of S-cone recipient receptive fields in subcortical pathways. Nearly everything we know about S-cone signals in the subcortical visual system comes from the study of visual systems in cats and primates (monkeys); in this review, we concentrate on results from macaque and marmoset monkeys. We discuss segregation of S-cone recipient (blue-on and blue-off) receptive fields in the dorsal lateral geniculate nucleus and describe their receptive field properties. We treat in some detail the question of detecting weak S-cone signals as an introduction for newcomers to the field. Finally, we briefly consider the question on how S-cone signals are distributed among nongeniculate targets.

  3. Prostate specific antigen detection using AlGaN /GaN high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Kang, B. S.; Wang, H. T.; Lele, T. P.; Tseng, Y.; Ren, F.; Pearton, S. J.; Johnson, J. W.; Rajagopal, P.; Roberts, J. C.; Piner, E. L.; Linthicum, K. J.

    2007-09-01

    Antibody-functionalized Au-gated AlGaN /GaN high electron mobility transistors (HEMTs) were used to detect prostate specific antigen (PSA). The PSA antibody was anchored to the gate area through the formation of carboxylate succinimdyl ester bonds with immobilized thioglycolic acid. The AlGaN /GaN HEMT drain-source current showed a rapid response of less than 5s when target PSA in a buffer at clinical concentrations was added to the antibody-immobilized surface. The authors could detect a wide range of concentrations from 10pg/mlto1μg/ml. The lowest detectable concentration was two orders of magnitude lower than the cutoff value of PSA measurements for clinical detection of prostate cancer. These results clearly demonstrate the promise of portable electronic biological sensors based on AlGaN /GaN HEMTs for PSA screening.

  4. Fuz Regulates Craniofacial Development through Tissue Specific Responses to Signaling Factors

    PubMed Central

    Zhang, Zichao; Wlodarczyk, Bogdan J.; Niederreither, Karen; Venugopalan, Shankar; Florez, Sergio; Finnell, Richard H.; Amendt, Brad A.

    2011-01-01

    The planar cell polarity effector gene Fuz regulates ciliogenesis and Fuz loss of function studies reveal an array of embryonic phenotypes. However, cilia defects can affect many signaling pathways and, in humans, cilia defects underlie several craniofacial anomalies. To address this, we analyzed the craniofacial phenotype and signaling responses of the Fuz−/− mice. We demonstrate a unique role for Fuz in regulating both Hedgehog (Hh) and Wnt/β-catenin signaling during craniofacial development. Fuz expression first appears in the dorsal tissues and later in ventral tissues and craniofacial regions during embryonic development coincident with cilia development. The Fuz−/− mice exhibit severe craniofacial deformities including anophthalmia, agenesis of the tongue and incisors, a hypoplastic mandible, cleft palate, ossification/skeletal defects and hyperplastic malformed Meckel's cartilage. Hh signaling is down-regulated in the Fuz null mice, while canonical Wnt signaling is up-regulated revealing the antagonistic relationship of these two pathways. Meckel's cartilage is expanded in the Fuz−/− mice due to increased cell proliferation associated with the up-regulation of Wnt canonical target genes and decreased non-canonical pathway genes. Interestingly, cilia development was decreased in the mandible mesenchyme of Fuz null mice, suggesting that cilia may antagonize Wnt signaling in this tissue. Furthermore, expression of Fuz decreased expression of Wnt pathway genes as well as a Wnt-dependent reporter. Finally, chromatin IP experiments demonstrate that β-catenin/TCF-binding directly regulates Fuz expression. These data demonstrate a new model for coordination of Hh and Wnt signaling and reveal a Fuz-dependent negative feedback loop controlling Wnt/β-catenin signaling. PMID:21935430

  5. Mitogen-activated protein kinases with distinct requirements for Ste5 scaffolding influence signaling specificity in Saccharomyces cerevisiae.

    PubMed

    Flatauer, Laura J; Zadeh, Sheena F; Bardwell, Lee

    2005-03-01

    Scaffold proteins are believed to enhance specificity in cell signaling when different pathways share common components. The prototype scaffold Ste5 binds to multiple components of the Saccharomyces cerevisiae mating pheromone response pathway, thereby conducting the mating signal to the Fus3 mitogen-activated protein kinase (MAPK). Some of the kinases that Ste5 binds to, however, are also shared with other pathways. Thus, it has been presumed that Ste5 prevents its bound kinases from transgressing into other pathways and protects them from intrusions from those pathways. Here we found that Fus3MAPK required Ste5 scaffolding to receive legitimate signals from the mating pathway as well as misdirected signals leaking from other pathways. Furthermore, increasing the cellular concentration of active Ste5 enhanced the channeling of inappropriate stimuli to Fus3. This aberrant signal crossover resulted in the erroneous induction of cell cycle arrest and mating. In contrast to Fus3, the Kss1 MAPK did not require Ste5 scaffolding to receive either authentic or leaking signals. Furthermore, the Ste11 kinase, once activated via Ste5, was able to signal to Kss1 independently of Ste5 scaffolding. These results argue that Ste5 does not act as a barrier that actively prevents signal crossover to Fus3 and that Ste5 may not effectively sequester its activated kinases away from other pathways. Rather, we suggest that specificity in this network is promoted by the selective activation of Ste5 and the distinct requirements of the MAPKs for Ste5 scaffolding. PMID:15713635

  6. Oocyte-specific deletion of Pten in mice reveals a stage-specific function of PTEN/PI3K signaling in oocytes in controlling follicular activation.

    PubMed

    Jagarlamudi, Krishna; Liu, Lian; Adhikari, Deepak; Reddy, Pradeep; Idahl, Annika; Ottander, Ulrika; Lundin, Eva; Liu, Kui

    2009-07-09

    Immature ovarian primordial follicles are essential for maintenance of the reproductive lifespan of female mammals. Recently, it was found that overactivation of the phosphatidylinositol 3-kinase (PI3K) signaling in oocytes of primordial follicles by an oocyte-specific deletion of Pten (phosphatase and tensin homolog deleted on chromosome ten), the gene encoding PI3K negative regulator PTEN, results in premature activation of the entire pool of primordial follicles, indicating that activation of the PI3K pathway in oocytes is important for control of follicular activation. To investigate whether PI3K signaling in oocytes of primary and further developed follicles also plays a role at later stages in follicular development and ovulation, we conditionally deleted the Pten gene from oocytes of primary and further developed follicles by using transgenic mice expressing zona pellucida 3 (Zp3) promoter-mediated Cre recombinase. Our results show that Pten was efficiently deleted from oocytes of primary and further developed follicles, as indicated by the elevated phosphorylation of the major PI3K downstream component Akt. However, follicular development was not altered and oocyte maturation was also normal, which led to normal fertility with unaltered litter size in the mutant mice. Our data indicate that properly controlled PTEN/PI3K-Akt signaling in oocytes is essential for control of the development of primordial follicles whereas overactivation of PI3K signaling in oocytes does not appear to affect the development of growing follicles. This suggests that there is a stage-specific function of PTEN/PI3K signaling in mouse oocytes that controls follicular activation.

  7. Bioelectronome. Integrated approach to receptor chemistry, radicals, electrochemistry, cell signaling, and physiological effects based on electron transfer.

    PubMed

    Kovacic, Peter; Pozos, Robert S

    2007-01-01

    Bioelectronome refers to the host of electron transfer (ET) reactions that occur in living systems. This review presents an integrated approach to receptor chemistry based on electron transfer, radicals, electrochemistry, cell signaling, and end result. First, receptor activity is addressed from the unifying standpoint of redox transformations in which various receptors are discussed. After a listing of receptor-binding modes, receptor chemistry is treated with focus on generation of reactive oxygen species (ROS), activation by ROS, and subsequent cell signaling involving ROS. A general electrostatic mechanism is proposed for receptor-ligand action with supporting evidence. Cell-signaling processes appear to entail electron transfer, ROS, redox chains, and relays. The widespread involvement of phosphate from phosphorylation may be rationalized electrostatically by analogy with DNA phosphate. Extensive evidence supports important participation of ET functionalities in the mechanism of drugs and toxins. The integrated approach is applied to the main ET classes, namely, quinones, metal complexes, iminium species, and aromatic nitro compounds.

  8. Inductive specification and axonal orientation of spinal neurons mediated by divergent bone morphogenetic protein signaling pathways

    PubMed Central

    2011-01-01

    Background Bone morphogenetic protein (BMP)7 evokes both inductive and axon orienting responses in dorsal interneurons (dI neurons) in the developing spinal cord. These events occur sequentially during the development of spinal neurons but in these and other cell types such inductive and acute chemotactic responses occur concurrently, highlighting the requirement for divergent intracellular signaling. Both type I and type II BMP receptor subtypes have been implicated selectively in orienting responses but it remains unclear how, in a given cell, divergence occurs. We have examined the mechanisms by which disparate BMP7 activities are generated in dorsal spinal neurons. Results We show that widely different threshold concentrations of BMP7 are required to elicit the divergent inductive and axon orienting responses. Type I BMP receptor kinase activity is required for activation of pSmad signaling and induction of dI character by BMP7, a high threshold response. In contrast, neither type I BMP receptor kinase activity nor Smad1/5/8 phosphorylation is involved in the low threshold orienting responses of dI axons to BMP7. Instead, BMP7-evoked axonal repulsion and growth cone collapse are dependent on phosphoinositide-3-kinase (PI3K) activation, plausibly through type II receptor signaling. BMP7 stimulates PI3K-dependent signaling in dI neurons. BMP6, which evokes neural induction but does not have orienting activity, activates Smad signaling but does not stimulate PI3K. Conclusions Divergent signaling through pSmad-dependent and PI3K-dependent (Smad-independent) mechanisms mediates the inductive and orienting responses of dI neurons to BMP7. A model is proposed whereby selective engagement of BMP receptor subunits underlies choice of signaling pathway. PMID:22085733

  9. Non-Coding RNA: Sequence-Specific Guide for Chromatin Modification and DNA Damage Signaling

    PubMed Central

    Francia, Sofia

    2015-01-01

    Chromatin conformation shapes the environment in which our genome is transcribed into RNA. Transcription is a source of DNA damage, thus it often occurs concomitantly to DNA damage signaling. Growing amounts of evidence suggest that different types of RNAs can, independently from their protein-coding properties, directly affect chromatin conformation, transcription and splicing, as well as promote the activation of the DNA damage response (DDR) and DNA repair. Therefore, transcription paradoxically functions to both threaten and safeguard genome integrity. On the other hand, DNA damage signaling is known to modulate chromatin to suppress transcription of the surrounding genetic unit. It is thus intriguing to understand how transcription can modulate DDR signaling while, in turn, DDR signaling represses transcription of chromatin around the DNA lesion. An unexpected player in this field is the RNA interference (RNAi) machinery, which play roles in transcription, splicing and chromatin modulation in several organisms. Non-coding RNAs (ncRNAs) and several protein factors involved in the RNAi pathway are well known master regulators of chromatin while only recent reports show their involvement in DDR. Here, we discuss the experimental evidence supporting the idea that ncRNAs act at the genomic loci from which they are transcribed to modulate chromatin, DDR signaling and DNA repair. PMID:26617633

  10. Layer specific and general requirements for ERK/MAPK signaling in the developing neocortex

    PubMed Central

    Xing, Lei; Larsen, Rylan S; Bjorklund, George Reed; Li, Xiaoyan; Wu, Yaohong; Philpot, Benjamin D; Snider, William D; Newbern, Jason M

    2016-01-01

    Aberrant signaling through the Raf/MEK/ERK (ERK/MAPK) pathway causes pathology in a family of neurodevelopmental disorders known as 'RASopathies' and is implicated in autism pathogenesis. Here, we have determined the functions of ERK/MAPK signaling in developing neocortical excitatory neurons. Our data reveal a critical requirement for ERK/MAPK signaling in the morphological development and survival of large Ctip2+ neurons in layer 5. Loss of Map2k1/2 (Mek1/2) led to deficits in corticospinal tract formation and subsequent corticospinal neuron apoptosis. ERK/MAPK hyperactivation also led to reduced corticospinal axon elongation, but was associated with enhanced arborization. ERK/MAPK signaling was dispensable for axonal outgrowth of layer 2/3 callosal neurons. However, Map2k1/2 deletion led to reduced expression of Arc and enhanced intrinsic excitability in both layers 2/3 and 5, in addition to imbalanced synaptic excitation and inhibition. These data demonstrate selective requirements for ERK/MAPK signaling in layer 5 circuit development and general effects on cortical pyramidal neuron excitability. DOI: http://dx.doi.org/10.7554/eLife.11123.001 PMID:26848828

  11. DC and small-signal physical models for the AlGaAs/GaAs high electron mobility transistor

    NASA Technical Reports Server (NTRS)

    Sarker, J. C.; Purviance, J. E.

    1991-01-01

    Analytical and numerical models are developed for the microwave small-signal performance, such as transconductance, gate-to-source capacitance, current gain cut-off frequency and the optimum cut-off frequency of the AlGaAs/GaAs High Electron Mobility Transistor (HEMT), in both normal and compressed transconductance regions. The validated I-V characteristics and the small-signal performances of four HeMT's are presented.

  12. The regulation of oncogenic Ras/ERK signalling by dual-specificity mitogen activated protein kinase phosphatases (MKPs).

    PubMed

    Kidger, Andrew M; Keyse, Stephen M

    2016-02-01

    Dual-specificity MAP kinase (MAPK) phosphatases (MKPs or DUSPs) are well-established negative regulators of MAPK signalling in mammalian cells and tissues. By virtue of their differential subcellular localisation and ability to specifically recognise, dephosphorylate and inactivate different MAPK isoforms, they are key spatiotemporal regulators of pathway activity. Furthermore, as they are transcriptionally regulated as downstream targets of MAPK signalling they can either act as classical negative feedback regulators or mediate cross talk between distinct MAPK pathways. Because MAPKs and particularly Ras/ERK signalling are implicated in cancer initiation and development, the observation that MKPs are abnormally regulated in human tumours has been interpreted as evidence that these enzymes can either suppress or promote carcinogenesis. However, definitive evidence of such roles has been lacking. Here we review recent work based on the use of mouse models, biochemical studies and clinical data that demonstrate key roles for MKPs in modulating the oncogenic potential of Ras/ERK signalling and also indicate that these enzymes may play a role in the response of tumours to certain anticancer drugs. Overall, this work reinforces the importance of negative regulatory mechanisms in modulating the activity of oncogenic MAPK signalling and indicates that MKPs may provide novel targets for therapeutic intervention in cancer. PMID:26791049

  13. MP3 compression and transmission of infrasonic sensor array signals and task-specific metrics for distortion evaluation

    NASA Astrophysics Data System (ADS)

    Cabrera, Sergio D.; Vidal, Edward, Jr.; Paramanandan, Smitha

    2005-08-01

    Infrasonic sensor arrays are very useful for detecting natural and man-made events. This paper describes part of an ongoing project for compressing and transmitting a set of infrasonic signals that need to be delivered to a remote location for decompression and processing. The project also deals with the evaluation of the effect of the compression distortion on the signals by the use of task-specific distortion metrics. We evaluate the effectiveness of the scheme using one hour worth of signals that were collected during a Space Shuttle launch using a small array of 4 microphones. The approach described here is to combine the 4 signals/channels using a transmultiplexer and to use an off-the-shelf audio compression method, namely the popular MP3 method which is based on subband coding. The transmultiplexer is a 5-channel Cosine-Modulated filterbank from which only the first 4 channels are used.. The codec used in this study is the readily available LAME software package which allows one to choose the output bits per second rate and to turn off the psychoacoustic model. To use an audio coder, the combined signal is first converted to 16 bits per sample and then associated with a 16 KHz. sampling frequency. In the application considered, the microphone signals are used to compute time evolving quantities including: average spectral coherence, beamforming, and phase velocity. These same quantities are used as task-specific metrics that reveal the distortion caused by the application of the MP3 compressor so that the user can evaluate distortion tolerances. From visual evaluation of these metrics we conclude that a compression ratio between 6.4:1 and 8:1 produces negligible distortion in the three task-specific metrics. The beamforming metric is the most sensitive to the compression distortion.

  14. Identification of a Novel Gene for Biosynthesis of a Bacteroid-Specific Electron Carrier Menaquinone

    PubMed Central

    Xie, Fuli; Cheng, Guojun; Xu, Hui; Wang, Zhi; Lei, Lei; Li, Youguo

    2011-01-01

    Ubiquinone (UQ) has been considered as an electron mediator in electron transfer that generates ATP in Rhizobium under both free-living and symbiosis conditions. When mutated, the dmtH gene has a symbiotic phenotype of forming ineffective nodules on Astragalus sinicus. The gene was isolated from a Mesorhizobium huakuii 7653R transposon-inserted mutant library. The DNA sequence and conserved protein domain analyses revealed that dmtH encodes demethylmenaquinone (DMK) methyltransferase, which catalyzes the terminal step of menaquinone (MK) biosynthesis. Comparative analysis indicated that dmtH homologs were present in only a few Rhizobia. Real-time quantitative PCR showed dmtH is a bacteroid-specific gene. The highest expression was seen at 25 days after inoculation of strain 7653R. Gene disruption and complementation tests demonstrated that the dmtH gene was essential for bacteroid development and symbiotic nitrogen fixation ability. MK and UQ were extracted from the wild type strain 7653R and mutant strain HK116. MK-7 was accumulated under microaerobic condition and UQ-10 was accumulated under aerobic condition in M. huakuii 7653R. The predicted function of DmtH protein was confirmed by the measurement of methyltransferase activity in vitro. These results revealed that MK-7 was used as an electron carrier instead of UQ in M. huakuii 7653R bacteroids. PMID:22194970

  15. APOBEC2, a selective inhibitor of TGFβ signaling, regulates left-right axis specification during early embryogenesis

    PubMed Central

    Vonica, Alin; Rosa, Alessandro; Arduini, Brigitte; Brivanlou, Ali H.

    2011-01-01

    The specification of left-right asymmetry is an evolutionarily conserved developmental process in vertebrates. The interplay between two TGFβ ligands, Derrière/GDF1 and Xnr1/Nodal, together with inhibitors such as Lefty and Coco/Cerl2, have been shown to provide the signals that lead to the establishment of laterality. However, molecular events leading to and following these signals remain mostly unknown. We find that APOBEC2, a member of the cytidine deaminase family of DNA/RNA editing enzymes, is induced by TGFβ signaling, and that its activity is necessary to specify the left-right axis in Xenopus and zebrafish embryos. Surprisingly, we find that APOBEC2 selectively inhibits Derrière, but not Xnr1, signaling. The inhibitory effect is conserved, as APOBEC2 blocks TGFβ signaling, and promotes muscle differentiation, in a mammalian myoblastic cell line. This demonstrates for the first time that a putative RNA/DNA editing enzyme regulates TGFβ signaling, and plays a major role in development. PMID:20880495

  16. Systematic dissection and trajectory-scanning mutagenesis of the molecular interface that ensures specificity of two-component signaling pathways.

    PubMed

    Capra, Emily J; Perchuk, Barrett S; Lubin, Emma A; Ashenberg, Orr; Skerker, Jeffrey M; Laub, Michael T

    2010-11-24

    Two-component signal transduction systems enable bacteria to sense and respond to a wide range of environmental stimuli. Sensor histidine kinases transmit signals to their cognate response regulators via phosphorylation. The faithful transmission of information through two-component pathways and the avoidance of unwanted cross-talk require exquisite specificity of histidine kinase-response regulator interactions to ensure that cells mount the appropriate response to external signals. To identify putative specificity-determining residues, we have analyzed amino acid coevolution in two-component proteins and identified a set of residues that can be used to rationally rewire a model signaling pathway, EnvZ-OmpR. To explore how a relatively small set of residues can dictate partner selectivity, we combined alanine-scanning mutagenesis with an approach we call trajectory-scanning mutagenesis, in which all mutational intermediates between the specificity residues of EnvZ and another kinase, RstB, were systematically examined for phosphotransfer specificity. The same approach was used for the response regulators OmpR and RstA. Collectively, the results begin to reveal the molecular mechanism by which a small set of amino acids enables an individual kinase to discriminate amongst a large set of highly-related response regulators and vice versa. Our results also suggest that the mutational trajectories taken by two-component signaling proteins following gene or pathway duplication may be constrained and subject to differential selective pressures. Only some trajectories allow both the maintenance of phosphotransfer and the avoidance of unwanted cross-talk.

  17. PLC-γ1 signaling plays a subtype-specific role in postbinding cell entry of influenza A virus.

    PubMed

    Zhu, Liqian; Ly, Hinh; Liang, Yuying

    2014-01-01

    Host signaling pathways and cellular proteins play important roles in the influenza viral life cycle and can serve as antiviral targets. In this study, we report the engagement of host phosphoinositide-specific phospholipase γ1 (PLC-γ1) in mediating cell entry of influenza virus H1N1 but not H3N2 subtype. Both PLC-γ1-specific inhibitor and short hairpin RNA (shRNA) strongly suppress the replication of H1N1 but not H3N2 viruses in cell culture, suggesting that PLC-γ1 plays an important subtype-specific role in the influenza viral life cycle. Further analyses demonstrate that PLC-γ1 activation is required for viral postbinding cell entry. In addition, H1N1, but not H3N2, infection leads to the phosphorylation of PLC-γ1 at Ser 1248 immediately after infection and independent of viral replication. We have further shown that H1N1-induced PLC-γ1 activation is downstream of epidermal growth factor receptor (EGFR) signaling. Interestingly, both H1N1 and H3N2 infections activate EGFR, but only H1N1 infection leads to PLC-γ1 activation. Taking our findings together, we have identified for the first time the subtype-specific interplay of host PLC-γ1 signaling and H1N1 virus that is critical for viral uptake early in the infection. Our study provides novel insights into how virus interacts with the cellular signaling network by demonstrating that viral determinants can regulate how the host signaling pathways function in virally infected cells.

  18. DFT calculations on atom-specific electronic properties of G/SiC(0001)

    NASA Astrophysics Data System (ADS)

    Kajihara, M.; Suzuki, T.; Shahed, S. M. F.; Komeda, T.; Minamitani, E.; Watanabe, S.

    2016-05-01

    We investigate the atom-specific interfacial electronic properties of the epitaxial graphene on Si-terminated SiC substrate using density functional theory (DFT) calculation with van der Waals interaction correction, focusing on the dependency of the local electronic state on the chemical environment. The band structure projected on the respective atomic orbitals of the carbon atoms in the buffer layer and uppermost Si atoms demonstrates that the dangling bonds of these atoms form band structures around the Fermi level. The contribution of each atom to the dangling bond states strongly depends on the chemical environment, i.e., the presence/absence of the interlayer Si-C covalent bond. This difference also affects the atom-specific local density of states of the top-layer graphene through its interaction with the substrate/buffer layer. We demonstrate that the bias voltage dependency of the scanning tunneling spectroscopy (STS) mapping image clearly reflects the presence of the dangling bonds of the buffer layer carbon or uppermost Si atom in the substrate, which would enable the detection of the buried dangling bond with an atomic spatial resolution via STS.

  19. Differential electron flow around photosystem I by two C4-photosynthetic-cell-specific ferredoxins

    PubMed Central

    Kimata-Ariga, Yoko; Matsumura, Tomohiro; Kada, Shigeki; Fujimoto, Hiroki; Fujita, Yuichi; Endo, Tsuyoshi; Mano, Jun’ichi; Sato, Fumihiko; Hase, Toshiharu

    2000-01-01

    In the C4 plant maize (Zea mays L.), two ferredoxin isoproteins, Fd I and Fd II, are expressed specifically in mesophyll and bundle-sheath cells, respectively. cDNAs for these ferredoxins were introduced separately into the cyanobacterium Plectonema boryanum with a disrupted endogenous ferredoxin gene, yielding TM202 and KM2-9 strains expressing Fd I and Fd II. The growth of TM202 was retarded under high light (130 µmol/m2/s), whereas KM2-9 grew at a normal rate but exhibited a nitrogen-deficient phenotype. Measurement of photosynthetic O2 evolution revealed that the reducing power was not efficiently partitioned into nitrogen assimilation in KM2-9. After starvation of the cells in darkness, the P700 oxidation level under far-red illumination increased significantly in TM202. However, it remained low in KM2-9, indicating an active cyclic electron flow. In accordance with this, the cellular ratio of ATP/ADP increased and that of NADPH/NADP+ decreased in KM2-9 as compared with TM202. These results demonstrated that the two cell type-specific ferredoxins differentially modulate electron flow around photosystem I. PMID:11013207

  20. Signal generation and mixing electronics for frequency-domain lifetime and spectral fluorometry

    NASA Technical Reports Server (NTRS)

    Cruce, Tommy Clay (Inventor); Hallidy, William H. (Inventor); Chin, Robert C. (Inventor)

    2007-01-01

    The present invention additionally comprises a method and apparatus for generating and mixing signals for frequency-domain lifetime and spectral fluorometry. The present invention comprises a plurality of signal generators that generate a plurality of signals where the signal generators modulate the amplitude and/or the frequency of the signals. The present invention uses one of these signals to drive an excitation signal that the present invention then directs and transmits at a target mixture, which absorbs the energy from the excitation signal. The property of fluorescence causes the target mixture to emit an emitted signal that the present invention detects with a signal detector. The present invention uses a plurality of mixers to produce a processor reference signal and a data signal. The present invention then uses a processor to compare the processor reference signal with the data signal by analyzing the differences in the phase and the differences in the amplitude between the two signals. The processor then extracts the fluorescence lifetime and fluorescence spectrum of the emitted signal from the phase and amplitude information using a chemometric analysis.

  1. Signal generation and mixing electronics for frequency-domain lifetime and spectral fluorometry

    NASA Technical Reports Server (NTRS)

    Cruce, Tommy C. (Inventor); Hallidy, William H. (Inventor); Chin, Robert C. (Inventor)

    1999-01-01

    The present invention additionally comprises a method and apparatus for generating and mixing signals for frequency-domain lifetime and spectral fluorometry. The present invention comprises a plurality of signal generators that generate a plurality of signals where the signal generators modulate the amplitude and/or the frequency of the signals. The present invention uses one of these signals to drive an excitation signal that the present invention then directs and transmits at a target mixture, which absorbs the energy from the excitation signal. The property of fluorescence causes the target mixture to emit an emitted signal that the present invention detects with a signal detector. The present invention uses a plurality of mixers to produce a processor reference signal and a data signal. The present invention then uses a processor to compare the processor reference signal with the data signal by analyzing the differences in the phase and the differences in the amplitude between the two signals. The processor then extracts the fluorescence lifetime and fluorescence spectrum of the emitted signal from the phase and amplitude information using a chemometric analysis.

  2. Species-specific effects on the optical signals of voltage-sensitive dyes.

    PubMed

    Ross, W N; Reichardt, L F

    1979-08-01

    The absorption changes of two merocyanine dyes in response to membrane potential changes were measured on several neuronal preparations to see whether the dyes would be useful in recording from these cells. We were able to record large signals without averaging from barnacle and leech neurons. The greatest signal with WW375 was seen at 750 nm. Much smaller increases in transmitted light intensity were seen at all other wavelengths between 500 and 780 nm. In contrast, vertebrate neuronal preparations produced much smaller signals with an entirely different action spectrum. Essentially the same spectrum was seen in cells of the sympathetic ganglion of the bullfrog, Rana catesbiana, dissociated chick spinal cord neurons, or dissociated rat superior cervical ganglion neurons. In each case an action potential was accompanied by increases in transmitted light intensity between 500 and 600 nm and 730 and 780 nm, and decreases in intensity between 600 and 730 nm with the dye WW375, the best dye tested. Similar results were obtained with dye NK2367 on both vertebrate and invertebrate preparations, except that the spectral properties were shifted 30 nm towards the blue. Both dyes caused some photodynamic damage to the cultured neurons after a few minute's exposure to the illuminating light. Several analogues of these dyes were also tried, but did not produce larger signals. PMID:490629

  3. Interplay of Specific Trans- and Juxtamembrane Interfaces in Plexin A3 Dimerization and Signal Transduction.

    PubMed

    Barton, Rachael; Khakbaz, Pouyan; Bera, Indrani; Klauda, Jeffery B; Iovine, M Kathryn; Berger, Bryan W

    2016-09-01

    Plexins are transmembrane proteins that serve as guidance receptors during angiogenesis, lymphangiogenesis, neuronal development, and zebrafish fin regeneration, with a putative role in cancer metastasis. Receptor dimerization or clustering, induced by extracellular ligand binding but modulated in part by the plexin transmembrane (TM) and juxtamembrane (JM) domains, is thought to drive plexin activity. Previous studies indicate that isolated plexin TM domains interact through a conserved, small-x3-small packing motif, and the cytosolic JM region interacts through a hydrophobic heptad repeat; however, the roles and interplay of these regions in plexin signal transduction remain unclear. Using an integrated experimental and simulation approach, we find disruption of the small-x3-small motifs in the Danio rerio Plexin A3 TM domain enhances dimerization of the TM-JM domain by enhancing JM-mediated dimerization. Furthermore, mutations of the cytosolic JM heptad repeat that disrupt dimerization do so even in the presence of TM domain mutations. However, mutations to the small-x3-small TM interfaces also disrupt Plexin A3 signaling in a zebrafish axonal guidance assay, indicating the importance of this TM interface in signal transduction. Collectively, our experimental and simulation results demonstrate that multiple TM and JM interfaces exist in the Plexin A3 homodimer, and these interfaces independently regulate dimerization that is important in Plexin A3 signal transduction.

  4. FGF signaling is required for anterior but not posterior specification of the murine liver bud

    PubMed Central

    Wang, Jikui; Rhee, Siyeon; Palaria, Amrita; Tremblay, Kimberly D.

    2014-01-01

    Background The definitive endoderm arises as a naive epithelial sheet that produces the entire gut tube and associated organs including the liver, pancreas and lungs. Murine explant studies demonstrate that Fibroblast Growth Factor (FGF) signaling from adjacent tissues is required to induce hepatic gene expression from isolated foregut endoderm. The requirement of FGF signaling during liver development is examined via small molecule inhibition during whole embryo culture. Results Loss of FGF signaling prior to hepatic induction results in morphological defects and gene expression changes that are confined to the anterior liver bud. In contrast the posterior portion of the liver bud remains relatively unaffected. Because FGF is thought to act as a morphogen during endoderm organogenesis, the ventral pancreas was also examined after FGF inhibition. Although the size of the ventral pancreas is not affected, loss of FGF signaling results in a significantly higher density of ventral pancreas cells. Conclusions The requirement for FGF-mediated induction of hepatic gene expression differs across the anterior-posterior axis of the developing liver bud. These results underscore the importance of studying tissue differentiation in the context of the whole embryo. PMID:25302779

  5. Domain Specificity of MAP3K Family Members, MLK and Tak1, for JNK Signaling in Drosophila

    PubMed Central

    Stronach, Beth; Lennox, Ashley L.; Garlena, Rebecca A.

    2014-01-01

    A highly diverse set of protein kinases functions as early responders in the mitogen- and stress-activated protein kinase (MAPK/SAPK) signaling pathways. For instance, humans possess 14 MAPK kinase kinases (MAP3Ks) that activate Jun kinase (JNK) signaling downstream. A major challenge is to decipher the selective and redundant functions of these upstream MAP3Ks. Taking advantage of the relative simplicity of Drosophila melanogaster as a model system, we assessed MAP3K signaling specificity in several JNK-dependent processes during development and stress response. Our approach was to generate molecular chimeras between two MAP3K family members, the mixed lineage kinase, Slpr, and the TGF-β activated kinase, Tak1, which share 32% amino acid identity across the kinase domain but otherwise differ in sequence and domain structure, and then test the contributions of various domains for protein localization, complementation of mutants, and activation of signaling. We found that overexpression of the wild-type kinases stimulated JNK signaling in alternate contexts, so cells were capable of responding to both MAP3Ks, but with distinct outcomes. Relative to wild-type, the catalytic domain swaps compensated weakly or not at all, despite having a shared substrate, the JNK kinase Hep. Tak1 C-terminal domain-containing constructs were inhibitory in Tak1 signaling contexts, including tumor necrosis factor-dependent cell death and innate immune signaling; however, depressing antimicrobial gene expression did not necessarily cause phenotypic susceptibility to infection. These same constructs were neutral in the context of Slpr-dependent developmental signaling, reflecting differential subcellular protein localization and by inference, point of activation. Altogether, our findings suggest that the selective deployment of a particular MAP3K can be attributed in part to its inherent sequence differences, cellular localization, and binding partner availability. PMID:24429281

  6. Specific analogues uncouple transport, signalling, oligo-ubiquitination and endocytosis in the yeast Gap1 amino acid transceptor.

    PubMed

    Van Zeebroeck, Griet; Rubio-Texeira, Marta; Schothorst, Joep; Thevelein, Johan M

    2014-07-01

    The Saccharomyces cerevisiae amino acid transceptor Gap1 functions as receptor for signalling to the PKA pathway and concomitantly undergoes substrate-induced oligo-ubiquitination and endocytosis. We have identified specific amino acids and analogues that uncouple to certain extent signalling, transport, oligo-ubiquitination and endocytosis. L-lysine, L-histidine and L-tryptophan are transported by Gap1 but do not trigger signalling. Unlike L-histidine, L-lysine triggers Gap1 oligo-ubiquitination without substantial induction of endocytosis. Two transported, non-metabolizable signalling agonists, β-alanine and D-histidine, are strong and weak inducers of Gap1 endocytosis, respectively, but both causing Gap1 oligo-ubiquitination. The non-signalling agonist, non-transported competitive inhibitor of Gap1 transport, L-Asp-γ-L-Phe, induces oligo-ubiquitination but no discernible endocytosis. The Km of L-citrulline transport is much lower than the threshold concentration for signalling and endocytosis. These results show that molecules can be transported without triggering signalling or substantial endocytosis, and that oligo-ubiquitination and endocytosis do not require signalling nor metabolism. Oligo-ubiquitination is required, but apparently not sufficient to trigger endocytosis. In addition, we demonstrate intracellular cross-induction of endocytosis of transport-defective Gap1(Y395C) by ubiquitination- and endocytosis-deficient Gap1(K9R,K16R). Our results support the concept that different substrates bind to partially overlapping binding sites in the same general substrate-binding pocket of Gap1, triggering divergent conformations, resulting in different conformation-induced downstream processes.

  7. One-step, multiplexed fluorescence detection of microRNAs based on duplex-specific nuclease signal amplification.

    PubMed

    Yin, Bin-Cheng; Liu, Yu-Qiang; Ye, Bang-Ce

    2012-03-21

    Traditional molecular beacons, widely applied for detection of nucleic acids, have an intrinsic limitation on sensitivity, as one target molecule converts only one beacon molecule to its fluorescent form. Herein, we take advantage of the duplex-specific nuclease (DSN) to create a new signal-amplifying mechanism, duplex-specific nuclease signal amplification (DSNSA), to increase the detection sensitivity of molecular beacons (Taqman probes). DSN nuclease is employed to recycle the process of target-assisted digestion of Taqman probes, thus, resulting in a significant fluorescence signal amplification through which one target molecule cleaves thousands of probe molecules. We further demonstrate the efficiency of this DSNSA strategy for rapid direct quantification of multiple miRNAs in biological samples. Our experimental results showed a quantitative measurement of sequence-specific miRNAs with the detection limit in the femtomolar range, nearly 5 orders of magnitude lower than that of conventional molecular beacons. This amplification strategy also demonstrated a high selectivity for discriminating differences between miRNA family members. Considering the superior sensitivity and specificity, as well as the multiplex and simple-to-implement features, this method promises a great potential of becoming a routine tool for simultaneously quantitative analysis of multiple miRNAs in tissues or cells, and supplies valuable information for biomedical research and clinical early diagnosis.

  8. Target accessibility and signal specificity in live-cell detection of BMP-4 mRNA using molecular beacons.

    PubMed

    Rhee, Won Jong; Santangelo, Philip J; Jo, Hanjoong; Bao, Gang

    2008-03-01

    The ability to visualize mRNA in single living cells and monitor in real-time the changes of mRNA level and localization can provide unprecedented opportunities for biological and disease studies. However, the mRNA detection specificity and sensitivity are critically dependent on the selection of target sequences and their accessibility. We carried out an extensive study of the target accessibility of BMP-4 mRNA using 10 different designs of molecular beacons (MBs), and identified the optimal beacon design. Specifically, for MB design 1 and 8 (MB1 and MB8), the fluorescent intensities from BMP-4 mRNA correlated well with the GFP signal after upregulating BMP-4 and co-expressing GFP using adenovirus, and the knockdown of BMP-4 mRNA using siRNA significantly reduced the beacon signals, demonstrating detection specificity. The beacon specificity was further confirmed using blocking RNA and in situ hybridization. We found that fluorescence signal from MBs depends critically on target sequences; the target sequences corresponding to siRNA sites may not be good sites for beacon-based mRNA detection, and vice versa. Possible beacon design rules are identified and approaches for enhancing target accessibility are discussed. This has significant implications to MB design for live cell mRNA detection.

  9. Kalkitoxin Inhibits Angiogenesis, Disrupts Cellular Hypoxic Signaling, and Blocks Mitochondrial Electron Transport in Tumor Cells

    PubMed Central

    Morgan, J. Brian; Liu, Yang; Coothankandaswamy, Veena; Mahdi, Fakhri; Jekabsons, Mika B.; Gerwick, William H.; Valeriote, Frederick A.; Zhou, Yu-Dong; Nagle, Dale G.

    2015-01-01

    The biologically active lipopeptide kalkitoxin was previously isolated from the marine cyanobacterium Moorea producens (Lyngbya majuscula). Kalkitoxin exhibited N-methyl-d-aspartate (NMDA)-mediated neurotoxicity and acted as an inhibitory ligand for voltage-sensitive sodium channels in cultured rat cerebellar granule neurons. Subsequent studies revealed that kalkitoxin generated a delayed form of colon tumor cell cytotoxicity in 7-day clonogenic cell survival assays. Cell line- and exposure time-dependent cytostatic/cytotoxic effects were previously observed with mitochondria-targeted inhibitors of hypoxia-inducible factor-1 (HIF-1). The transcription factor HIF-1 functions as a key regulator of oxygen homeostasis. Therefore, we investigated the ability of kalkitoxin to inhibit hypoxic signaling in human tumor cell lines. Kalkitoxin potently and selectively inhibited hypoxia-induced activation of HIF-1 in T47D breast tumor cells (IC50 5.6 nM). Mechanistic studies revealed that kalkitoxin inhibits HIF-1 activation by suppressing mitochondrial oxygen consumption at electron transport chain (ETC) complex I (NADH-ubiquinone oxidoreductase). Further studies indicate that kalkitoxin targets tumor angiogenesis by blocking the induction of angiogenic factors (i.e., VEGF) in tumor cells. PMID:25803180

  10. Development of a compact electron spin resonance system for measuring ESR signals of irradiated fingernails.

    PubMed

    Suzuki, Hirosuke; Tamukai, Kenji; Yoshida, Naoki; Ohya, Hiroaki; Kato, Katsuhisa; Anzai, Kazunori; Swartz, Harold M

    2010-02-01

    The aims of this study were to develop and improve the sensitivity of an electron spin resonance (ESR) spectrometer and to demonstrate its functionality for dosimetry in measuring ESR signals from radiation-exposed fingernails. The newly-developed spectrometer was a lightweight (22 kg) one-box ESR device with a resonator showing a Q-factor higher than that of a previous Keycom model, which is quieter, without influence from magnetic modulation, and contains a fingernail positioner. The authors obtained the best measurement result after the cavity Q-factor was increased to more than 7,200 by continuous polishing of the inner surface of the cavity using deerskin. The common mode noise of "magic T" was also successfully decreased to as low as one-half by completely tuning the arm balance. Moreover, the flatness of the modulated magnetic field was increased by as much as two-fold by changing the coil conformation. These efforts markedly decreased the noise level and extended downwardly the linear portion of dose dependence.

  11. Intracellular cytoplasm-specific delivery of SH3 and SH2 domains of SLAP inhibits TcR-mediated signaling.

    PubMed

    Kim, Jung-Ho; Moon, Jae-Seung; Yu, JiSang; Lee, Sang-Kyou

    2015-05-01

    Signaling events triggered by T cell receptor (TcR) stimulation are important targets for the development of common therapeutics for various autoimmune diseases. SLAP is a negative regulator of TcR-mediated signaling cascade via targeting TcR zeta chain for degradation through recruiting the ubiquitin ligase c-Cbl. In this study, we generated a transducible form of SH3 and SH2 domains of SLAP (ctSLAPΔC) which can be specifically targeted to the cytoplasm of a cell. ctSLAPΔC inhibited tyrosine phosphorylation of signaling mediators such as ZAP-70 and LAT involved in T cell activation, and effectively suppressed transcriptional activity of NFAT and NFκB upon TcR stimulation. The transduced ctSLAPΔC in T cells blocked the secretion of T cell-specific cytokines such as IL-2, IFNγ, IL-17A, and IL-4 and induced the expression of CD69 and CD25 on effector T cells without influencing the cell viability. Inhibition of TcR-mediated signaling via SLAP blocked the differentiation of naïve T cells into Th1, Th2 or Treg cells with different sensitivity, suggesting that qualitative and quantitative intensity of TcR-mediated signaling in the context of polarizing cytokines environment may be a critical factor to determine the differentiation fate of naïve T cells. These results suggest that cytoplasm-specific transduction of the SH3 and SH2 domains of SLAP has a therapeutic potential of being an immunosuppressive reagent for the treatment of various autoimmune diseases. PMID:25800872

  12. Intracellular cytoplasm-specific delivery of SH3 and SH2 domains of SLAP inhibits TcR-mediated signaling.

    PubMed

    Kim, Jung-Ho; Moon, Jae-Seung; Yu, JiSang; Lee, Sang-Kyou

    2015-05-01

    Signaling events triggered by T cell receptor (TcR) stimulation are important targets for the development of common therapeutics for various autoimmune diseases. SLAP is a negative regulator of TcR-mediated signaling cascade via targeting TcR zeta chain for degradation through recruiting the ubiquitin ligase c-Cbl. In this study, we generated a transducible form of SH3 and SH2 domains of SLAP (ctSLAPΔC) which can be specifically targeted to the cytoplasm of a cell. ctSLAPΔC inhibited tyrosine phosphorylation of signaling mediators such as ZAP-70 and LAT involved in T cell activation, and effectively suppressed transcriptional activity of NFAT and NFκB upon TcR stimulation. The transduced ctSLAPΔC in T cells blocked the secretion of T cell-specific cytokines such as IL-2, IFNγ, IL-17A, and IL-4 and induced the expression of CD69 and CD25 on effector T cells without influencing the cell viability. Inhibition of TcR-mediated signaling via SLAP blocked the differentiation of naïve T cells into Th1, Th2 or Treg cells with different sensitivity, suggesting that qualitative and quantitative intensity of TcR-mediated signaling in the context of polarizing cytokines environment may be a critical factor to determine the differentiation fate of naïve T cells. These results suggest that cytoplasm-specific transduction of the SH3 and SH2 domains of SLAP has a therapeutic potential of being an immunosuppressive reagent for the treatment of various autoimmune diseases.

  13. CqsA-CqsS quorum-sensing signal-receptor specificity in Photobacterium angustum.

    PubMed

    Ke, Xiaobo; Miller, Laura C; Ng, Wai-Leung; Bassler, Bonnie L

    2014-02-01

    Quorum sensing (QS) is a process of bacterial cell-cell communication that relies on the production, detection and population-wide response to extracellular signal molecules called autoinducers. The QS system commonly found in vibrios and photobacteria consists of the CqsA synthase/CqsS receptor pair. Vibrio cholerae CqsA/S synthesizes and detects (S)-3-hydroxytridecan-4-one (C10-CAI-1), whereas Vibrio harveyi produces and detects a distinct but similar molecule, (Z)-3-aminoundec-2-en-4-one (Ea-C8-CAI-1). To understand the signalling properties of the larger family of CqsA-CqsS pairs, here, we characterize the Photobacterium angustum CqsA/S system. Many photobacterial cqsA genes harbour a conserved frameshift mutation that abolishes CAI-1 production. By contrast, their cqsS genes are intact. Correcting the P. angustum cqsA reading frame restores production of a mixture of CAI-1 moieties, including C8-CAI-1, C10-CAI-1, Ea-C8-CAI-1 and Ea-C10-CAI-1. This signal production profile matches the P. angustum CqsS receptor ligand-detection capability. The receptor exhibits a preference for molecules with 10-carbon tails, and the CqsS Ser(168) residue governs this preference. P. angustum can overcome the cqsA frameshift to produce CAI-1 under particular limiting growth conditions presumably through a ribosome slippage mechanism. Thus, we propose that P. angustum uses CAI-1 signalling for adaptation to stressful environments. PMID:24372841

  14. CqsA-CqsS quorum-sensing signal-receptor specificity in Photobacterium angustum.

    PubMed

    Ke, Xiaobo; Miller, Laura C; Ng, Wai-Leung; Bassler, Bonnie L

    2014-02-01

    Quorum sensing (QS) is a process of bacterial cell-cell communication that relies on the production, detection and population-wide response to extracellular signal molecules called autoinducers. The QS system commonly found in vibrios and photobacteria consists of the CqsA synthase/CqsS receptor pair. Vibrio cholerae CqsA/S synthesizes and detects (S)-3-hydroxytridecan-4-one (C10-CAI-1), whereas Vibrio harveyi produces and detects a distinct but similar molecule, (Z)-3-aminoundec-2-en-4-one (Ea-C8-CAI-1). To understand the signalling properties of the larger family of CqsA-CqsS pairs, here, we characterize the Photobacterium angustum CqsA/S system. Many photobacterial cqsA genes harbour a conserved frameshift mutation that abolishes CAI-1 production. By contrast, their cqsS genes are intact. Correcting the P. angustum cqsA reading frame restores production of a mixture of CAI-1 moieties, including C8-CAI-1, C10-CAI-1, Ea-C8-CAI-1 and Ea-C10-CAI-1. This signal production profile matches the P. angustum CqsS receptor ligand-detection capability. The receptor exhibits a preference for molecules with 10-carbon tails, and the CqsS Ser(168) residue governs this preference. P. angustum can overcome the cqsA frameshift to produce CAI-1 under particular limiting growth conditions presumably through a ribosome slippage mechanism. Thus, we propose that P. angustum uses CAI-1 signalling for adaptation to stressful environments.

  15. Accounting for photophysical processes and specific signal intensity changes in fluorescence-detected sedimentation velocity.

    PubMed

    Zhao, Huaying; Ma, Jia; Ingaramo, Maria; Andrade, Eric; MacDonald, Jeff; Ramsay, Glen; Piszczek, Grzegorz; Patterson, George H; Schuck, Peter

    2014-09-16

    Fluorescence detected sedimentation velocity (FDS-SV) has emerged as a powerful technique for the study of high-affinity protein interactions, with hydrodynamic resolution exceeding that of diffusion-based techniques, and with sufficient sensitivity for binding studies at low picomolar concentrations. For the detailed quantitative analysis of the observed sedimentation boundaries, it is necessary to adjust the conventional sedimentation models to the FDS data structure. A key consideration is the change in the macromolecular fluorescence intensity during the course of the experiment, caused by slow drifts of the excitation laser power, and/or by photophysical processes. In the present work, we demonstrate that FDS-SV data have inherently a reference for the time-dependent macromolecular signal intensity, resting on a geometric link between radial boundary migration and plateau signal. We show how this new time-domain can be exploited to study molecules exhibiting photobleaching and photoactivation. This expands the application of FDS-SV to proteins tagged with photoswitchable fluorescent proteins, organic dyes, or nanoparticles, such as those recently introduced for subdiffraction microscopy and enables FDS-SV studies of their interactions and size distributions. At the same time, we find that conventional fluorophores undergo minimal photobleaching under standard illumination in the FDS. These findings support the application of a high laser power density for the detection, which we demonstrate can further increase the signal quality.

  16. Sudan Black B treatment reduces autofluorescence and improves resolution of in situ hybridization specific fluorescent signals of brain sections.

    PubMed

    Oliveira, V C; Carrara, R C V; Simoes, D L C; Saggioro, F P; Carlotti, C G; Covas, D T; Neder, L

    2010-08-01

    Interference by autofluorescence is one of the major concerns of immunofluorescence analysis of in situ hybridization-based diagnostic assays. We present a useful technique that reduces autofluorescent background without affecting the tissue integrity or direct immunofluorescence signals in brain sections. Using six different protocols, such as ammonia/ethanol, Sudan Black B (SBB) in 70% ethanol, photobleaching with UV light and different combinations of them in both formalin-fixed paraffin-embedded and frozen human brain tissue sections, we have found that tissue treatment of SBB in a concentration of 0.1% in 70% ethanol is the best approach to reduce/eliminate tissue autofluorescence and background, while preserving the specific fluorescence hybridization signals. This strategy is a feasible, non-time consuming method that provides a reasonable compromise between total reduction of the tissue autofluorescence and maintenance of specific fluorescent labels.

  17. A Novel Transcriptional Factor Nkapl Is a Germ Cell-Specific Suppressor of Notch Signaling and Is Indispensable for Spermatogenesis

    PubMed Central

    Okuda, Hidenobu; Kiuchi, Hiroshi; Takao, Tetsuya; Miyagawa, Yasushi; Tsujimura, Akira; Nonomura, Norio; Miyata, Haruhiko; Okabe, Masaru; Ikawa, Masahito; Kawakami, Yoshitaka; Goshima, Naoki; Wada, Morimasa; Tanaka, Hiromitsu

    2015-01-01

    Spermatogenesis is an elaborately regulated system dedicated to the continuous production of spermatozoa via the genesis of spermatogonia. In this process, a variety of genes are expressed that are relevant to the differentiation of germ cells at each stage. Although Notch signaling plays a critical role in germ cell development in Drosophila and Caenorhabditis elegans, its function and importance for spermatogenesis in mammals is controversial. We report that Nkapl is a novel germ cell-specific transcriptional suppressor in Notch signaling. It is also associated with several molecules of the Notch corepressor complex such as CIR, HDAC3, and CSL. It was expressed robustly in spermatogonia and early spermatocytes after the age of 3 weeks. Nkapl-deleted mice showed complete arrest at the level of pachytene spermatocytes. In addition, apoptosis was observed in this cell type. Overexpression of NKAPL in germline stem cells demonstrated that Nkapl induced changes in spermatogonial stem cell (SSC) markers and the reduction of differentiation factors through the Notch signaling pathway, whereas testes with Nkapl deleted showed inverse changes in those markers and factors. Therefore, Nkapl is indispensable because aberrantly elevated Notch signaling has negative effects on spermatogenesis, affecting SSC maintenance and differentiation factors. Notch signaling should be properly regulated through the transcriptional factor Nkapl. PMID:25875095

  18. Dissecting signaling through activation of specific Src-effector complexes in vivo

    PubMed Central

    Karginov, A.V.; Tsygankov, D.; Berginski, M.; Chu, P.-H.; Trudeau, E.D.; Yi, J.J.; Gomez, S.; Elston, T.C.; Hahn, K.M.

    2014-01-01

    We describe an approach to selectively activate a kinase in a specific protein complex or at a specific subcellular location within living cells, and within minutes. This reveals the effects of specific kinase pathways without time for genetic compensation. The new technique, dubbed RapRTAP (rapamycin regulated targeted activation of pathways) was used to dissect the role of Src kinase interactions with FAK and p130Cas in cell motility and morphodynamics. The overall effects of Src activation on cell morphology and adhesion dynamics were first quantified, without restricting effector access. Subsets of Src induced behaviors were then attributed to specific interactions between Src and the two downstream proteins. Activation of Src in the cytoplasm versus at the cell membrane also produced distinct phenotypes. The conserved nature of the kinase site modified for RapRTAP indicates that the technique can be applied to many kinases. PMID:24609359

  19. Retinoid signaling and Neurogenin2 function are coupled for the specification of spinal motor neurons through a chromatin modifier CBP

    PubMed Central

    Lee, Seunghee; Lee, Bora; Lee, Jae W.; Lee, Soo-Kyung

    2009-01-01

    SUMMARY Extracellular signals and cell-intrinsic transcription factors cooperatively instruct generation of diverse neurons. However, little is known about how neural progenitors integrate both cues and orchestrate chromatin changes for neuronal specification. Here, we report that extrinsic signal retinoic acid (RA) and intrinsic transcription factor Neurogenin2 (Ngn2) collaboratively trigger transcriptionally active chromatin in spinal motor neuron genes during development. Retinoic acid receptor (RAR) binds Ngn2 and is thereby recruited to motor neuron genes targeted by Ngn2. RA then facilitates the recruitment of a histone acetyltransferase CBP to the Ngn2/RAR-complex, markedly inducing histone H3/H4-acetylation. Correspondingly, timely inactivation of CBP and its paralogue p300 results in profound defects in motor neuron specification and motor axonal projection, accompanied by significantly reduced histone H3-acetylation of the motor neuron enhancer. Our study uncovers the mechanism by which extrinsic RA-signal and intrinsic transcription factor Ngn2 cooperate for cell-fate specification through their synergistic activity to trigger transcriptionally active chromatin. PMID:19524524

  20. Differential regulation of Tec1 by Fus3 and Kss1 confers signaling specificity in yeast development.

    PubMed

    Brückner, Stefan; Köhler, Tim; Braus, Gerhard H; Heise, Barbara; Bolte, Melanie; Mösch, Hans-Ulrich

    2004-12-01

    Transcriptional regulation by mitogen-activated protein (MAP) kinase signaling cascades is a major control mechanism for eukaryotic development. In budding yeast, Fus3 and Kss1 are two MAP kinases that control two distinct developmental programs-mating and invasive growth. We investigated whether signal-specific activation of mating and invasive growth involves regulation of the transcription factor Tec1 by Fus3 and Kss1. We present evidence that, during mating, Fus3 phosphorylates Tec1 to downregulate this invasive growth-specific transcription factor and its target genes. This function of Fus3 is essential for correct execution of the mating program and is not shared by Kss1. We find that Kss1 controls the activity of Tec1 mainly during invasive growth by control of TEC1 gene expression. Our study suggests that signaling specificity can arise from differential regulation of a single transcription factor by two MAP kinases with shared functions in distinct developmental programs. PMID:15558284

  1. Constructing Patient Specific Clinical Trajectories from Electronic Healthcare Reimbursement Claims using Sequential Pattern Mining

    SciTech Connect

    Pullum, Laura L; Hobson, Tanner C

    2015-01-01

    We examine the use of electronic healthcare reimbursement claims (EHRC) for analyzing healthcare delivery and practice patterns across the United States (US). By analyzing over 1 billion EHRCs, we track patterns of clinical procedures administered to patients with heart disease (HD) using sequential pattern mining algorithms. Our analyses reveal that the clinical procedures performed on HD patients are highly varied leading up to and after the primary diagnosis. The discovered clinical procedure sequences reveal significant differences in the overall costs incurred across different parts of the US, indicating significant heterogeneity in treating HD patients. We show that a data-driven approach to understand patient specific clinical trajectories constructed from EHRC can provide quantitative insights into how to better manage and treat patients.

  2. Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Wang, Wen; Cheng, Meng-Yun; Long, Peng-Cheng; Hu, Li-Qin

    2015-07-01

    The specific absorbed fractions (SAF) for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom, which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human (CVH) data set by the FDS Team. The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10 keV to 4 MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models. The differences were due to the racial and anatomical differences in organ mass and inter-organ distance. The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03040000), National Natural Science Foundation of China (910266004, 11305205, 11305203) and National Special Program for ITER (2014GB112001)

  3. Layer-specific interference with cholinergic signaling in the prefrontal cortex by smoking concentrations of nicotine.

    PubMed

    Poorthuis, Rogier B; Bloem, Bernard; Verhoog, Matthijs B; Mansvelder, Huibert D

    2013-03-13

    Adolescence is a period in which the developing prefrontal cortex (PFC) is sensitive to maladaptive changes when exposed to nicotine. Nicotine affects PFC function and repeated exposure to nicotine during adolescence impairs attention performance and impulse control during adulthood. Nicotine concentrations experienced by smokers are known to desensitize nicotinic acetylcholine receptors (nAChRs), but the impact thereof on PFC circuits is poorly understood. Here, we investigated how smoking concentrations of nicotine (100-300 nm) interfere with cholinergic signaling in the mouse PFC. nAChR desensitization depends on subunit composition. Since nAChR subunits are differentially expressed across layers of the PFC neuronal network, we hypothesized that cholinergic signaling through nAChRs across layers would suffer differentially from exposure to nicotine. Throughout the PFC, nicotine strongly desensitized responses to ACh in neurons expressing β2* nAChRs, whereas ACh responses mediated by α7 nAChRs were not hampered. The amount of desensitization of β2* nAChR currents depended on neuron type and cortical layer. β2*-mediated responses of interneurons in LII-III and LVI completely desensitized, while cholinergic responses in LV interneurons and LVI pyramidal cells showed less desensitization. This discrepancy depended on α5 subunit expression. Two-photon imaging of neuronal population activity showed that prolonged exposure to nicotine limited cholinergic signaling through β2* nAChRs to deep PFC layers where α5 subunits were expressed. Together, our results demonstrate a layer-dependent decrease in cholinergic activation of the PFC through nAChRs by nicotine. These mechanisms may be one of the first steps leading up to the pathophysiological changes associated with nicotine exposure during adolescence.

  4. Episodic neonatal hypoxia evokes executive dysfunction and regionally specific alterations in markers of dopamine signaling.

    PubMed

    Decker, M J; Hue, G E; Caudle, W M; Miller, G W; Keating, G L; Rye, D B

    2003-01-01

    Perinatal ischemic-anoxic and prolonged anoxic insults lead to impaired dopaminergic signaling and are hypothesized to contribute, at least in part, to the pathogenesis of disorders of minimal brain dysfunction such as attention-deficit hyperactivity disorder. We hypothesized that subtle intermittent hypoxic insults, occurring during a period of critical brain development, are also pathogenic to dopaminergic signaling, thereby contributing to behavioral and executive dysfunction. Between postnatal days 7 and 11, rat pups were exposed to either 20-s bursts of isocapnic hypoxic gas, compressed air, or were left undisturbed with the dam. On postnatal days 23 pups were instrumented with electroencephalographic/electromyographic electrodes and sleep-wake architecture was characterized. Locomotor activity was assessed between postnatal days 35 and 38, learning, and working memory evaluated between postnatal days 53 and 64. Rats were killed on postnatal day 80 and tyrosine hydroxylase, vesicular monoamine transporter, dopamine transporter, and dopamine D1 receptors were quantified in the prefrontal cortex, primary sensorimotor cortex, and precommissural striatum by Western blot analyses. Post-hypoxic pups spent less time awake and more time in rapid-eye-movement sleep during the lights-on phase of the circadian cycle, were hyperlocomotive, and expressed impaired working memory. Striatal expression of vesicular monoamine transporter and D1 receptor proteins were increased in post-hypoxic rats, consistent with depressed dopaminergic signaling. These observations lead to the intriguing hypothesis that intermittent hypoxia occurring during a period of critical brain development evokes behavioral and neurochemical alterations that are long lasting, and consistent with disorders of minimal brain dysfunction. PMID:12614682

  5. Heuristic Chemistry--A Qualitative Study on Teaching Domain-Specific Strategies for the Six-Electron Case

    ERIC Educational Resources Information Center

    Graulich, Nicole; Tiemann, Rudiger; Schreiner, Peter R.

    2012-01-01

    We investigate the efficiency of domain-specific heuristic strategies in mastering and predicting pericyclic six-electron rearrangements. Based on recent research findings on these types of reactions a new concept has been developed that should help students identify and describe six-electron rearrangements more readily in complex molecules. The…

  6. GABA signalling modulates plant growth by directly regulating the activity of plant-specific anion transporters

    PubMed Central

    Ramesh, Sunita A.; Tyerman, Stephen D.; Xu, Bo; Bose, Jayakumar; Kaur, Satwinder; Conn, Vanessa; Domingos, Patricia; Ullah, Sana; Wege, Stefanie; Shabala, Sergey; Feijó, José A.; Ryan, Peter R.; Gillham, Matthew

    2015-01-01

    The non-protein amino acid, gamma-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to biotic and abiotic stress, and regulates plant growth. Until now it was not known whether GABA exerts its effects in plants through the regulation of carbon metabolism or via an unidentified signalling pathway. Here, we demonstrate that anion flux through plant aluminium-activated malate transporter (ALMT) proteins is activated by anions and negatively regulated by GABA. Site-directed mutagenesis of selected amino acids within ALMT proteins abolishes GABA efficacy but does not alter other transport properties. GABA modulation of ALMT activity results in altered root growth and altered root tolerance to alkaline pH, acid pH and aluminium ions. We propose that GABA exerts its multiple physiological effects in plants via ALMT, including the regulation of pollen tube and root growth, and that GABA can finally be considered a legitimate signalling molecule in both the plant and animal kingdoms. PMID:26219411

  7. Building Specific Signals from Frequency Chaos Game and Revealing Periodicities Using a Smoothed Fourier Analysis.

    PubMed

    Messaoudi, Imen; Elloumi-Oueslati, Afef; Lachiri, Zied

    2014-01-01

    Investigating the roles and functions of DNA within genomes is becoming a primary focus of genomic research. Thus, the research works are moving towards cooperation between different scientific disciplines which aims at facilitating the interpretation of genetic information. In order to characterize the DNA of living organisms, signal processing tools appear to be very suitable for such study. However, a DNA sequence must be converted into a numerical sequence before processing; which defines the concept of DNA coding. In line with this, we propose a new one dimensional model based on the chaos game representation theory called Frequency Chaos Game Signal: FCGS. Then, we perform a Smoothed Fourier Transform to enhance hidden periodicities in the C.elegans DNA sequences. Through this study, we demonstrate the performance of our coding approach in highlighting characteristic periodicities. Indeed, several periodicities are shown to be involved in the 1D spectra and the 2D spectrograms of FCGSs. To investigate further about the contribution of our method in the enhancement of characteristic spectral attributes, a comparison with a range of binary indicators is established.

  8. Building Specific Signals from Frequency Chaos Game and Revealing Periodicities Using a Smoothed Fourier Analysis.

    PubMed

    Messaoudi, Imen; Elloumi-Oueslati, Afef; Lachiri, Zied

    2014-01-01

    Investigating the roles and functions of DNA within genomes is becoming a primary focus of genomic research. Thus, the research works are moving towards cooperation between different scientific disciplines which aims at facilitating the interpretation of genetic information. In order to characterize the DNA of living organisms, signal processing tools appear to be very suitable for such study. However, a DNA sequence must be converted into a numerical sequence before processing; which defines the concept of DNA coding. In line with this, we propose a new one dimensional model based on the chaos game representation theory called Frequency Chaos Game Signal: FCGS. Then, we perform a Smoothed Fourier Transform to enhance hidden periodicities in the C.elegans DNA sequences. Through this study, we demonstrate the performance of our coding approach in highlighting characteristic periodicities. Indeed, several periodicities are shown to be involved in the 1D spectra and the 2D spectrograms of FCGSs. To investigate further about the contribution of our method in the enhancement of characteristic spectral attributes, a comparison with a range of binary indicators is established. PMID:26356859

  9. Protons at the speed of sound: Predicting specific biological signaling from physics

    NASA Astrophysics Data System (ADS)

    Fichtl, Bernhard; Shrivastava, Shamit; Schneider, Matthias F.

    2016-05-01

    Local changes in pH are known to significantly alter the state and activity of proteins and enzymes. pH variations induced by pulses propagating along soft interfaces (e.g. membranes) would therefore constitute an important pillar towards a physical mechanism of biological signaling. Here we investigate the pH-induced physical perturbation of a lipid interface and the physicochemical nature of the subsequent acoustic propagation. Pulses are stimulated by local acidification and propagate – in analogy to sound – at velocities controlled by the interface’s compressibility. With transient local pH changes of 0.6 directly observed at the interface and velocities up to 1.4 m/s this represents hitherto the fastest protonic communication observed. Furthermore simultaneously propagating mechanical and electrical changes in the lipid interface are detected, exposing the thermodynamic nature of these pulses. Finally, these pulses are excitable only beyond a threshold for protonation, determined by the pKa of the lipid head groups. This protonation-transition plus the existence of an enzymatic pH-optimum offer a physical basis for intra- and intercellular signaling via sound waves at interfaces, where not molecular structure and mechano-enyzmatic couplings, but interface thermodynamics and thermodynamic transitions are the origin of the observations.

  10. Distinct Signaling of Coreceptors Regulates Specific Metabolism Pathways and Impacts Memory Development in CAR T Cells.

    PubMed

    Kawalekar, Omkar U; O'Connor, Roddy S; Fraietta, Joseph A; Guo, Lili; McGettigan, Shannon E; Posey, Avery D; Patel, Prachi R; Guedan, Sonia; Scholler, John; Keith, Brian; Snyder, Nathaniel W; Snyder, Nathaniel; Blair, Ian A; Blair, Ian; Milone, Michael C; June, Carl H

    2016-02-16

    Chimeric antigen receptors (CARs) redirect T cell cytotoxicity against cancer cells, providing a promising approach to cancer immunotherapy. Despite extensive clinical use, the attributes of CAR co-stimulatory domains that impact persistence and resistance to exhaustion of CAR-T cells remain largely undefined. Here, we report the influence of signaling domains of coreceptors CD28 and 4-1BB on the metabolic characteristics of human CAR T cells. Inclusion of 4-1BB in the CAR architecture promoted the outgrowth of CD8(+) central memory T cells that had significantly enhanced respiratory capacity, increased fatty acid oxidation and enhanced mitochondrial biogenesis. In contrast, CAR T cells with CD28 domains yielded effector memory cells with a genetic signature consistent with enhanced glycolysis. These results provide, at least in part, a mechanistic insight into the differential persistence of CAR-T cells expressing 4-1BB or CD28 signaling domains in clinical trials and inform the design of future CAR T cell therapies. PMID:26885860

  11. Protons at the speed of sound: Predicting specific biological signaling from physics

    PubMed Central

    Fichtl, Bernhard; Shrivastava, Shamit; Schneider, Matthias F.

    2016-01-01

    Local changes in pH are known to significantly alter the state and activity of proteins and enzymes. pH variations induced by pulses propagating along soft interfaces (e.g. membranes) would therefore constitute an important pillar towards a physical mechanism of biological signaling. Here we investigate the pH-induced physical perturbation of a lipid interface and the physicochemical nature of the subsequent acoustic propagation. Pulses are stimulated by local acidification and propagate – in analogy to sound – at velocities controlled by the interface’s compressibility. With transient local pH changes of 0.6 directly observed at the interface and velocities up to 1.4 m/s this represents hitherto the fastest protonic communication observed. Furthermore simultaneously propagating mechanical and electrical changes in the lipid interface are detected, exposing the thermodynamic nature of these pulses. Finally, these pulses are excitable only beyond a threshold for protonation, determined by the pKa of the lipid head groups. This protonation-transition plus the existence of an enzymatic pH-optimum offer a physical basis for intra- and intercellular signaling via sound waves at interfaces, where not molecular structure and mechano-enyzmatic couplings, but interface thermodynamics and thermodynamic transitions are the origin of the observations. PMID:27216038

  12. Critical role of segment-specific packaging signals in genetic reassortment of influenza A viruses

    PubMed Central

    Essere, Boris; Yver, Matthieu; Gavazzi, Cyrille; Terrier, Olivier; Isel, Catherine; Fournier, Emilie; Giroux, Fabienne; Textoris, Julien; Julien, Thomas; Socratous, Clio; Rosa-Calatrava, Manuel; Lina, Bruno; Marquet, Roland; Moules, Vincent

    2013-01-01

    The fragmented nature of the influenza A genome allows the exchange of gene segments when two or more influenza viruses infect the same cell, but little is known about the rules underlying this process. Here, we studied genetic reassortment between the A/Moscow/10/99 (H3N2, MO) virus originally isolated from human and the avian A/Finch/England/2051/91 (H5N2, EN) virus and found that this process is strongly biased. Importantly, the avian HA segment never entered the MO genetic background alone but always was accompanied by the avian PA and M fragments. Introduction of the 5′ and 3′ packaging sequences of HAMO into an otherwise HAEN backbone allowed efficient incorporation of the chimerical viral RNA (vRNA) into the MO genetic background. Furthermore, forcing the incorporation of the avian M segment or introducing five silent mutations into the human M segment was sufficient to drive coincorporation of the avian HA segment into the MO genetic background. These silent mutations also strongly affected the genotype of reassortant viruses. Taken together, our results indicate that packaging signals are crucial for genetic reassortment and that suboptimal compatibility between the vRNA packaging signals, which are detected only when vRNAs compete for packaging, limit this process. PMID:24043788

  13. The relationship between oscillatory EEG activity and the laminar-specific BOLD signal.

    PubMed

    Scheeringa, René; Koopmans, Peter J; van Mourik, Tim; Jensen, Ole; Norris, David G

    2016-06-14

    Electrophysiological recordings in animals have indicated that visual cortex γ-band oscillatory activity is predominantly observed in superficial cortical layers, whereas α- and β-band activity is stronger in deep layers. These rhythms, as well as the different cortical layers, have also been closely related to feedforward and feedback streams of information. Recently, it has become possible to measure laminar activity in humans with high-resolution functional MRI (fMRI). In this study, we investigated whether these different frequency bands show a differential relation with the laminar-resolved blood-oxygen level-dependent (BOLD) signal by combining data from simultaneously recorded EEG and fMRI from the early visual cortex. Our visual attention paradigm allowed us to investigate how variations in strength over trials and variations in the attention effect over subjects relate to each other in both modalities. We demonstrate that γ-band EEG power correlates positively with the superficial layers' BOLD signal and that β-power is negatively correlated to deep layer BOLD and α-power to both deep and superficial layer BOLD. These results provide a neurophysiological basis for human laminar fMRI and link human EEG and high-resolution fMRI to systems-level neuroscience in animals.

  14. Protons at the speed of sound: Predicting specific biological signaling from physics.

    PubMed

    Fichtl, Bernhard; Shrivastava, Shamit; Schneider, Matthias F

    2016-01-01

    Local changes in pH are known to significantly alter the state and activity of proteins and enzymes. pH variations induced by pulses propagating along soft interfaces (e.g. membranes) would therefore constitute an important pillar towards a physical mechanism of biological signaling. Here we investigate the pH-induced physical perturbation of a lipid interface and the physicochemical nature of the subsequent acoustic propagation. Pulses are stimulated by local acidification and propagate - in analogy to sound - at velocities controlled by the interface's compressibility. With transient local pH changes of 0.6 directly observed at the interface and velocities up to 1.4 m/s this represents hitherto the fastest protonic communication observed. Furthermore simultaneously propagating mechanical and electrical changes in the lipid interface are detected, exposing the thermodynamic nature of these pulses. Finally, these pulses are excitable only beyond a threshold for protonation, determined by the pKa of the lipid head groups. This protonation-transition plus the existence of an enzymatic pH-optimum offer a physical basis for intra- and intercellular signaling via sound waves at interfaces, where not molecular structure and mechano-enyzmatic couplings, but interface thermodynamics and thermodynamic transitions are the origin of the observations. PMID:27216038

  15. Distinct Signaling of Coreceptors Regulates Specific Metabolism Pathways and Impacts Memory Development in CAR T Cells.

    PubMed

    Kawalekar, Omkar U; O'Connor, Roddy S; Fraietta, Joseph A; Guo, Lili; McGettigan, Shannon E; Posey, Avery D; Patel, Prachi R; Guedan, Sonia; Scholler, John; Keith, Brian; Snyder, Nathaniel W; Snyder, Nathaniel; Blair, Ian A; Blair, Ian; Milone, Michael C; June, Carl H

    2016-02-16

    Chimeric antigen receptors (CARs) redirect T cell cytotoxicity against cancer cells, providing a promising approach to cancer immunotherapy. Despite extensive clinical use, the attributes of CAR co-stimulatory domains that impact persistence and resistance to exhaustion of CAR-T cells remain largely undefined. Here, we report the influence of signaling domains of coreceptors CD28 and 4-1BB on the metabolic characteristics of human CAR T cells. Inclusion of 4-1BB in the CAR architecture promoted the outgrowth of CD8(+) central memory T cells that had significantly enhanced respiratory capacity, increased fatty acid oxidation and enhanced mitochondrial biogenesis. In contrast, CAR T cells with CD28 domains yielded effector memory cells with a genetic signature consistent with enhanced glycolysis. These results provide, at least in part, a mechanistic insight into the differential persistence of CAR-T cells expressing 4-1BB or CD28 signaling domains in clinical trials and inform the design of future CAR T cell therapies.

  16. Identifying ligand-specific signalling within biased responses: focus on δ opioid receptor ligands

    PubMed Central

    Charfi, I; Audet, N; Bagheri Tudashki, H; Pineyro, G

    2015-01-01

    Opioids activate GPCRs to produce powerful analgesic actions but at the same time induce side effects and generate tolerance, which restrict their clinical use. Reducing this undesired response profile has remained a major goal of opioid research and the notion of ‘biased agonism’ is raising increasing interest as a means of separating therapeutic responses from unwanted side effects. However, to fully exploit this opportunity, it is necessary to confidently identify biased signals and evaluate which type of bias may support analgesia and which may lead to undesired effects. The development of new computational tools has made it possible to quantify ligand-dependent signalling and discriminate this component from confounders that may also yield biased responses. Here, we analyse different approaches to identify and quantify ligand-dependent bias and review different types of confounders. Focus is on δ opioid receptor ligands, which are currently viewed as promising agents for chronic pain management. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2 PMID:24665881

  17. Cardiac-Specific SOCS3 Deletion Prevents In Vivo Myocardial Ischemia Reperfusion Injury through Sustained Activation of Cardioprotective Signaling Molecules

    PubMed Central

    Nagata, Takanobu; Yasukawa, Hideo; Kyogoku, Sachiko; Oba, Toyoharu; Takahashi, Jinya; Nohara, Shoichiro; Minami, Tomoko; Mawatari, Kazutoshi; Sugi, Yusuke; Shimozono, Koutatsu; Pradervand, Sylvain; Hoshijima, Masahiko; Aoki, Hiroki; Fukumoto, Yoshihiro; Imaizumi, Tsutomu

    2015-01-01

    Myocardial ischemia reperfusion injury (IRI) adversely affects cardiac performance and the prognosis of patients with acute myocardial infarction. Although myocardial signal transducer and activator of transcription (STAT) 3 is potently cardioprotective during IRI, the inhibitory mechanism responsible for its activation is largely unknown. The present study aimed to investigate the role of the myocardial suppressor of cytokine signaling (SOCS)-3, an intrinsic negative feedback regulator of the Janus kinase (JAK)-STAT signaling pathway, in the development of myocardial IRI. Myocardial IRI was induced in mice by ligating the left anterior descending coronary artery for 1 h, followed by different reperfusion times. One hour after reperfusion, the rapid expression of JAK-STAT–activating cytokines was observed. We precisely evaluated the phosphorylation of cardioprotective signaling molecules and the expression of SOCS3 during IRI and then induced myocardial IRI in wild-type and cardiac-specific SOCS3 knockout mice (SOCS3-CKO). The activation of STAT3, AKT, and ERK1/2 rapidly peaked and promptly decreased during IRI. This decrease correlated with the induction of SOCS3 expression up to 24 h after IRI in wild-type mice. The infarct size 24 h after reperfusion was significantly reduced in SOCS3-CKO compared with wild-type mice. In SOCS3-CKO mice, STAT3, AKT, and ERK1/2 phosphorylation was sustained, myocardial apoptosis was prevented, and the expression of anti-apoptotic Bcl-2 family member myeloid cell leukemia-1 (Mcl-1) was augmented. Cardiac-specific SOCS3 deletion led to the sustained activation of cardioprotective signaling molecules including and prevented myocardial apoptosis and injury during IRI. Our findings suggest that SOCS3 may represent a key factor that exacerbates the development of myocardial IRI. PMID:26010537

  18. Polycomb-Mediated Repression and Sonic Hedgehog Signaling Interact to Regulate Merkel Cell Specification during Skin Development.

    PubMed

    Perdigoto, Carolina N; Dauber, Katherine L; Bar, Carmit; Tsai, Pai-Chi; Valdes, Victor J; Cohen, Idan; Santoriello, Francis J; Zhao, Dejian; Zheng, Deyou; Hsu, Ya-Chieh; Ezhkova, Elena

    2016-07-01

    An increasing amount of evidence indicates that developmental programs are tightly regulated by the complex interplay between signaling pathways, as well as transcriptional and epigenetic processes. Here, we have uncovered coordination between transcriptional and morphogen cues to specify Merkel cells, poorly understood skin cells that mediate light touch sensations. In murine dorsal skin, Merkel cells are part of touch domes, which are skin structures consisting of specialized keratinocytes, Merkel cells, and afferent neurons, and are located exclusively around primary hair follicles. We show that the developing primary hair follicle functions as a niche required for Merkel cell specification. We find that intraepidermal Sonic hedgehog (Shh) signaling, initiated by the production of Shh ligand in the developing hair follicles, is required for Merkel cell specification. The importance of Shh for Merkel cell formation is further reinforced by the fact that Shh overexpression in embryonic epidermal progenitors leads to ectopic Merkel cells. Interestingly, Shh signaling is common to primary, secondary, and tertiary hair follicles, raising the possibility that there are restrictive mechanisms that regulate Merkel cell specification exclusively around primary hair follicles. Indeed, we find that loss of Polycomb repressive complex 2 (PRC2) in the epidermis results in the formation of ectopic Merkel cells that are associated with all hair types. We show that PRC2 loss expands the field of epidermal cells competent to differentiate into Merkel cells through the upregulation of key Merkel-differentiation genes, which are known PRC2 targets. Importantly, PRC2-mediated repression of the Merkel cell differentiation program requires inductive Shh signaling to form mature Merkel cells. Our study exemplifies how the interplay between epigenetic and morphogen cues regulates the complex patterning and formation of the mammalian skin structures. PMID:27414999

  19. Polycomb-Mediated Repression and Sonic Hedgehog Signaling Interact to Regulate Merkel Cell Specification during Skin Development

    PubMed Central

    Bar, Carmit; Tsai, Pai-Chi; Valdes, Victor J.; Cohen, Idan; Santoriello, Francis J.; Zhao, Dejian; Hsu, Ya-Chieh; Ezhkova, Elena

    2016-01-01

    An increasing amount of evidence indicates that developmental programs are tightly regulated by the complex interplay between signaling pathways, as well as transcriptional and epigenetic processes. Here, we have uncovered coordination between transcriptional and morphogen cues to specify Merkel cells, poorly understood skin cells that mediate light touch sensations. In murine dorsal skin, Merkel cells are part of touch domes, which are skin structures consisting of specialized keratinocytes, Merkel cells, and afferent neurons, and are located exclusively around primary hair follicles. We show that the developing primary hair follicle functions as a niche required for Merkel cell specification. We find that intraepidermal Sonic hedgehog (Shh) signaling, initiated by the production of Shh ligand in the developing hair follicles, is required for Merkel cell specification. The importance of Shh for Merkel cell formation is further reinforced by the fact that Shh overexpression in embryonic epidermal progenitors leads to ectopic Merkel cells. Interestingly, Shh signaling is common to primary, secondary, and tertiary hair follicles, raising the possibility that there are restrictive mechanisms that regulate Merkel cell specification exclusively around primary hair follicles. Indeed, we find that loss of Polycomb repressive complex 2 (PRC2) in the epidermis results in the formation of ectopic Merkel cells that are associated with all hair types. We show that PRC2 loss expands the field of epidermal cells competent to differentiate into Merkel cells through the upregulation of key Merkel-differentiation genes, which are known PRC2 targets. Importantly, PRC2-mediated repression of the Merkel cell differentiation program requires inductive Shh signaling to form mature Merkel cells. Our study exemplifies how the interplay between epigenetic and morphogen cues regulates the complex patterning and formation of the mammalian skin structures. PMID:27414999

  20. Correlative Confocal and 3D Electron Microscopy of a Specific Sensory Cell

    PubMed Central

    Bohórquez, Diego; Haque, Fariha; Medicetty, Satish; Liddle, Rodger A.

    2015-01-01

    Delineation of a cell’s ultrastructure is important for understanding its function. This can be a daunting project for rare cell types diffused throughout tissues made of diverse cell types, such as enteroendocrine cells of the intestinal epithelium. These gastrointestinal sensors of food and bacteria have been difficult to study because they are dispersed among other epithelial cells at a ratio of 1:1,000. Recently, transgenic reporter mice have been generated to identify enteroendocrine cells by means of fluorescence. One of those is the peptide YY-GFP mouse. Using this mouse, we developed a method to correlate confocal and serial block-face scanning electron microscopy. We named the method cocem3D and applied it to identify a specific enteroendocrine cell in tissue and unveil the cell’s ultrastructure in 3D. The resolution of cocem3D is sufficient to identify organelles as small as secretory vesicles and to distinguish cell membranes for volume rendering. Cocem3D can be easily adapted to study the 3D ultrastructure of other specific cell types in their native tissue. PMID:26273796

  1. Concerted Hydrogen Atom and Electron Transfer Mechanism for Catalysis by Lysine-Specific Demethylase

    PubMed Central

    Yu, Tao; Higashi, Masahiro; Cembran, Alessandro; Gao, Jiali; Truhlar, Donald G.

    2015-01-01

    We calculate the free energy profile for the postulated hydride transfer reaction mechanism for the catalysis of lysine demethylation by lysine-specific demethylase LSD1. The potential energy surface is obtained by using combined electrostatically embedded multi-configuration molecular mechanics (EE-MCMM) and single-configuration molecular mechanics (MM). We employ a constant valence bond coupling term to obtain analytical energies and gradients of the EE-MCMM subsystem, which contains 45 QM atoms and which is parametrized with a density functional calculations employing specific reaction parameters obtained by matching high-level wave function calculations. In the MM region, we employ the Amber ff03 and TIP3P force fields. The free energy of activation at 300 K is calculated by molecular dynamics (MD) umbrella sampling on a system with 102090 atoms as the maximum of the free energy profile along the reaction coordinate as obtained by the weighted histogram analysis method with 17 umbrella sampling windows. This yields a free energy of activation of only 10 kcal/mol, showing that the previously postulated direct hydride transfer reaction mechanism is plausible, although we find that it is better interpreted as a concerted transfer of a hydrogen atom and an electron. PMID:23725223

  2. Correlation of Radiation and Electron and Neutron Signals at PF-1000

    SciTech Connect

    Kubes, P.; Kravarik, J.; Barvir, P.; Klir, D.; Scholz, M.; Paduch, M.; Tomaszewski, K.; Ivanova-Stanik, I.; Bienkowska, B.; Ryc, L.; Karpinski, L.; Juha, L.; Krasa, J.; Sadowski, M. J.; Skladnik-Sadowska, E.; Jakubowski, L.; Szydlowski, A.; Malinowska, A.; Malinowski, K.; Schmidt, H.

    2006-01-15

    At the signals of x-rays usually 2 peaks were observed. The first peak corresponded to the time of the minimum diameter of the imploding plasma sheath (pinch phase) recorded by the visible frames. The second peak occurred 150-200 ns later at the time of the development of instabilities. High-energy electrons registered in the upstream and downstream directions differed in the intensity (ratio 3:1) and in the time of production. Their peaks correlated with x-rays. The energy of neutrons and time of their generation were determined by time-of-flight method from the pulses of seven scintillation detectors positioned in the axial direction. At the rise-time, each neutron pulse has registered downstream energies in range of 2.7-3.2 MeV. The final part of neutron pulse has isotropic energy distribution with energies up to 2.6-2.7 MeV. The evolution of the neutron pulses correlates with the visible frames. The first pulse correlates with the fast downstream zipper-effect of the dense plasma in the pinch and with the forming of the radiating ball-shaped structure at the bottom of the dilating plasma sheath. The second neutron pulse correlates with the second pinching and exploding of the plasma of lower density and with existence of the structure of the dense plasma positioned at the bottom of the dilating current sheath, similarly to the first pulse. The neutrons have a non-thermal beam-target origin. A possible influence of the zipper-effect on the acceleration of deuterons and on the plasma heating is discussed.

  3. Backprojection of GNSS total-electron content signals for recent large earthquakes

    NASA Astrophysics Data System (ADS)

    Mikesell, T. D.; Rolland, L.; Haney, M. M.; Larmat, C. S.; Lee, R.

    2015-12-01

    It is well known that earthquakes and tsunamis couple energy into the dynamically fluid atmosphere. This energy can propagate up to the ionosphere where we can observe perturbations in the total-electron content (TEC) signals measured by global navigation space systems (GNSS). Recent emphasis has been placed on using these new observables to characterize earthquake and tsunami hazards from space, as well as for planetary exploration. Backprojection is an array-based imaging technique used in seismology to characterize the seismic source location, including complex energy release patterns from large earthquakes. Here we present TEC backprojection results from 3 recent earthquakes - 1) 2009 Samoa triggered doublet (Mw 8.1), 2) 2011 Van dip-slip event (Mw 7.1) and 3) 2012 Haida Gwaii strike-slip underthrust event (Mw 7.8). Each of these events presents new obstacles to overcome if backprojection is to be used routinely to monitor hazards from space. We will discuss these obstacles in detail and present approaches to overcome them. For instance, one problem arises from the fact that the observation point is non-stationary in time because the satellites are moving. Another problem stems from the relative geometry of the geomagnetic field and the incoming acoustic wave at the ionosphere. Finally, we present array-based methods to reduce artifacts in the backprojection images, e.g. array deconvolution, and we show that under favorable circumstances, this approach can be used to characterize motion at the Earth surface from space with high temporal and spatial resolution.

  4. Transgenic zebrafish reveal tissue-specific differences in estrogen signaling in response to environmental water samples

    USGS Publications Warehouse

    Gorelick, Daniel A.; Iwanowicz, Luke R.; Hung, Alice L.; Blazer, Vicki; Halpern, Marnie E.

    2014-01-01

    Background: Environmental endocrine disruptors (EED) are exogenous chemicals that mimic endogenous hormones, such as estrogens. Previous studies using a zebrafish transgenic reporter demonstrated that the EEDs bisphenol A and genistein preferentially activate estrogen receptors (ER) in the larval heart compared to the liver. However, it was not known whether the transgenic zebrafish reporter was sensitive enough to detect estrogens from environmental samples, whether environmental estrogens would exhibit similar tissue-specific effects as BPA and genistein or why some compounds preferentially target receptors in the heart. Methods: We tested surface water samples using a transgenic zebrafish reporter with tandem estrogen response elements driving green fluorescent protein expression (5xERE:GFP). Reporter activation was colocalized with tissue-specific expression of estrogen receptor genes by RNA in situ hybridization. Results: Selective patterns of ER activation were observed in transgenic fish exposed to river water samples from the Mid-Atlantic United States, with several samples preferentially activating receptors in embryonic and larval heart valves. We discovered that tissue-specificity in ER activation is due to differences in the expression of estrogen receptor subtypes. ERα is expressed in developing heart valves but not in the liver, whereas ERβ2 has the opposite profile. Accordingly, subtype-specific ER agonists activate the reporter in either the heart valves or the liver. Conclusion: The use of 5xERE:GFP transgenic zebrafish has revealed an unexpected tissue-specific difference in the response to environmentally relevant estrogenic compounds. Exposure to estrogenic EEDs in utero is associated with adverse health effects, with the potentially unanticipated consequence of targeting developing heart valves.

  5. Bioluminescent signals spatially amplified by wavelength-specific diffusion through the shell of a marine snail

    PubMed Central

    Deheyn, Dimitri D.; Wilson, Nerida G.

    2011-01-01

    Some living organisms produce visible light (bioluminescence) for intra- or interspecific visual communication. Here, we describe a remarkable bioluminescent adaptation in the marine snail Hinea brasiliana. This species produces a luminous display in response to mechanical stimulation caused by encounters with other motile organisms. The light is produced from discrete areas on the snail's body beneath the snail's shell, and must thus overcome this structural barrier to be viewed by an external receiver. The diffusion and transmission efficiency of the shell is greater than a commercial diffuser reference material. Most strikingly, the shell, although opaque and pigmented, selectively diffuses the blue-green wavelength of the species bioluminescence. This diffusion generates a luminous display that is enlarged relative to the original light source. This unusual shell thus allows spatially amplified outward transmission of light communication signals from the snail, while allowing the animal to remain safely inside its hard protective shell. PMID:21159673

  6. Interplay of environmental signals and progenitor diversity on fate specification of cortical GABAergic neurons

    PubMed Central

    Romcy-Pereira, Rodrigo N.

    2015-01-01

    Cortical GABAergic interneurons constitute an extremely diverse population of cells organized in a well-defined topology of precisely interconnected cells. They play a crucial role regulating inhibitory-excitatory balance in brain circuits, gating sensory perception, and regulating spike timing to brain oscillations during distinct behaviors. Dysfunctions in the establishment of proper inhibitory circuits have been associated to several brain disorders such as autism, epilepsy, and schizophrenia. In the rodent adult cortex, inhibitory neurons are generated during the second gestational week from distinct progenitor lineages located in restricted domains of the ventral telencephalon. However, only recently, studies have revealed some of the mechanisms generating the heterogeneity of neuronal subtypes and their modes of integration in brain networks. Here we will discuss some the events involved in the production of cortical GABAergic neuron diversity with focus on the interaction between intrinsically driven genetic programs and environmental signals during development. PMID:25972784

  7. Prolonged signaling at the parathyroid hormone receptor by peptide ligands targeted to a specific receptor conformation

    PubMed Central

    Okazaki, Makoto; Ferrandon, Sebastien; Vilardaga, Jean-Pierre; Bouxsein, Mary L.; Potts, John T.; Gardella, Thomas J.

    2008-01-01

    The parathyroid hormone receptor (PTHR) is a class B G protein-coupled receptor that plays critical roles in bone and mineral ion metabolism. Ligand binding to the PTHR involves interactions to both the amino-terminal extracellular (N) domain, and transmembrane/extracellular loop, or juxtamembrane (J) regions of the receptor. Recently, we found that PTH(1–34), but not PTH-related protein, PTHrP(1–36), or M-PTH(1–14) (M = Ala/Aib1,Aib3,Gln10,Har11,Ala12,Trp14,Arg19), binds to the PTHR in a largely GTPγS-resistant fashion, suggesting selective binding to a novel, high-affinity conformation (R0), distinct from the GTPγS-sensitive conformation (RG). We examined the effects in vitro and in vivo of introducing the M substitutions, which enhance interaction to the J domain, into PTH analogs extended C-terminally to incorporate residues involved in the N domain interaction. As compared with PTH(1–34), M-PTH(1–28) and M-PTH(1–34) bound to R0 with higher affinity, produced more sustained cAMP responses in cells, formed more stable complexes with the PTHR in FRET and subcellular localization assays, and induced more prolonged calcemic and phosphate responses in mice. Moreover, after 2 weeks of daily injection in mice, M-PTH(1–34) induced larger increases in trabecular bone volume and greater increases in cortical bone turnover, than did PTH(1–34). Thus, the putative R0 PTHR conformation can form highly stable complexes with certain PTH ligand analogs and thereby mediate surprisingly prolonged signaling responses in bone and/or kidney PTH target cells. Controlling, via ligand analog design, the selectivity with which a PTH ligand binds to R0, versus RG, may be a strategy for optimizing signaling duration time, and hence therapeutic efficacy, of PTHR agonist ligands. PMID:18946036

  8. Specific induction of cranial placode cells from Xenopus ectoderm by modulating the levels of BMP, Wnt, and FGF signaling.

    PubMed

    Watanabe, Tomoko; Kanai, Yuna; Matsukawa, Shinya; Michiue, Tatsuo

    2015-10-01

    The neural-epidermal boundary tissues include the neural crest and preplacodal ectoderm (PPE) as primordial constituents. The PPE region is essential for the development of various sensory and endocrine organs, such as the anterior lobe of the pituitary, olfactory epithelium, lens, trigeminal ganglion, and otic vesicles. During gastrulation, a neural region is induced in ectodermal cells that interacts with mesendodermal tissue and responds to several secreted factors. Among them, inhibition of bone morphogenetic protein (BMP) in the presumptive neuroectoderm is essential for the induction of neural regions, and formation of a Wnt and fibroblast growth factor (FGF) signaling gradient along the midline determines anterior-posterior patterning. In this study, we attempted to specifically induce PPE cells from undifferentiated Xenopus cells by regulating BMP, Wnt, and FGF signaling. We showed that the proper level of BMP inhibition with an injection of truncated BMP receptor or treatment with a chemical antagonist triggered the expression of PPE genes. In addition, by varying the amount of injected chordin, we optimized specific expression of the PPE genes. PPE gene expression is increased by adding an appropriate dose of an FGF receptor antagonist. Furthermore, co-injection with either wnt8 or the Wnt inhibitor dkk-1 altered the expression levels of several region-specific genes according to the injected dose. We specifically induced PPE cell differentiation in animal cap cells from early-stage Xenopus embryos by modulating BMP, Wnt, and FGF signaling. This is not the first research on placode induction, but our simple method could potentially be applied to mammalian stem cell systems. PMID:26249012

  9. A novel T cell receptor single-chain signaling complex mediates antigen-specific T cell activity and tumor control

    PubMed Central

    Stone, Jennifer D.; Harris, Daniel T.; Soto, Carolina M.; Chervin, Adam S.; Aggen, David H.; Roy, Edward J.; Kranz, David M.

    2014-01-01

    Adoptive transfer of genetically modified T cells to treat cancer has shown promise in several clinical trials. Two main strategies have been applied to redirect T cells against cancer: 1) introduction of a full-length T cell receptor (TCR) specific for a tumor-associated peptide-MHC, or 2) introduction of a chimeric antigen receptor (CAR), including an antibody fragment specific for a tumor cell surface antigen, linked intracellularly to T cell signaling domains. Each strategy has advantages and disadvantages for clinical applications. Here, we present data on the in vitro and in vivo effectiveness of a single-chain signaling receptor incorporating a TCR variable fragment as the targeting element (referred to as TCR-SCS). This receptor contained a single-chain TCR (Vβ-linker-Vα) from a high-affinity TCR called m33, linked to the intracellular signaling domains of CD28 and CD3ζ. This format avoided mispairing with endogenous TCR chains, and mediated specific T cell activity when expressed in either CD4 or CD8 T cells. TCR-SCS-transduced CD8-negative cells showed an intriguing sensitivity, compared to full-length TCRs, to higher densities of less stable pepMHC targets. T cells that expressed this peptide-specific receptor persisted in vivo, and exhibited polyfunctional responses. Growth of metastatic antigen-positive tumors was significantly inhibited by T cells that expressed this receptor, and tumor cells that escaped were antigen loss variants. TCR-SCS receptors represent an alternative targeting receptor strategy that combines the advantages of single-chain expression, avoidance of TCR chain mispairing, and targeting of intracellular antigens presented in complex with MHC proteins. PMID:25082071

  10. Divergent branches of mitochondrial signaling regulate specific genes and the viability of specialized cell types of differentiated yeast colonies

    PubMed Central

    Rešetárová, Stanislava; Kučerová, Helena; Hlaváček, Otakar; Váchová, Libuše; Palková, Zdena

    2016-01-01

    Mitochondrial retrograde signaling mediates communication from altered mitochondria to the nucleus and is involved in many normal and pathophysiological changes, including cell metabolic reprogramming linked to cancer development and progression in mammals. The major mitochondrial retrograde pathway described in yeast includes three activators, Rtg1p, Rtg2p and Rtg3p, and repressors, Mks1p and Bmh1p/Bmh2p. Using differentiated yeast colonies, we show that Mks1p-Rtg pathway regulation is complex and includes three branches that divergently regulate the properties and fate of three specifically localized cell subpopulations via signals from differently altered mitochondria. The newly identified RTG pathway-regulated genes ATO1/ATO2 are expressed in colonial upper (U) cells, the cells with active TORC1 that metabolically resemble tumor cells, while CIT2 is a typical target induced in one subpopulation of starving lower (L) cells. The viability of the second L cell subpopulation is strictly dependent on RTG signaling. Additional co-activators of Rtg1p-Rtg3p specific to particular gene targets of each branch are required to regulate cell differentiation. PMID:26992228

  11. MYC/MAX control ERK signaling and pluripotency by regulation of dual-specificity phosphatases 2 and 7.

    PubMed

    Chappell, James; Sun, Yuhua; Singh, Amar; Dalton, Stephen

    2013-04-01

    Suppression of extracellular signal-regulated kinase (ERK) signaling is an absolute requirement for the maintenance of murine pluripotent stem cells (mPSCs) and requires the MYC-binding partner MAX. In this study, we define a mechanism for this by showing that MYC/MAX complexes suppress ERK activity by transcriptionally regulating two members of the dual-specificity phosphatase (DUSP) family. DUSPs function by binding and then inactivating ERK1,2 by dephosphorylating residues required for catalytic activity. MYC/MAX complexes achieve this by binding the promoters of DUSP2 and DUSP7, leading to their transcriptional activation, resulting in the attenuation of ERK activity. In the absence of MYC, ectopic DUSP2,7 expression severely delays differentiation, while loss of DUSP2,7 ectopically activates ERK, resulting in loss of pluripotency. These findings elucidate a novel regulatory role for MYC in PSC maintenance involving the stimulation of phosphatases that directly inhibit the MAPK/ERK signaling pathway. Moreover, it provides a mechanism for how leukemia inhibitory factor (LIF)/STAT3 signaling reaches across to the MAPK/ERK pathway through MYC and MAX to sustain pluripotency.

  12. Conservation of a maternal-specific methylation signal at the human IGF2R locus.

    PubMed

    Smrzka, O W; Faé, I; Stöger, R; Kurzbauer, R; Fischer, G F; Henn, T; Weith, A; Barlow, D P

    1995-10-01

    The human IGF2R gene has been reported to be either biallelically or very rarely monoallelically expressed, in contrast to the maternally expressed mouse counterpart. We describe here an analysis of the 5' portion of the human IGF2R gene and show that it contains a maternally methylated CpG island in the second intron. A similar maternally methylated intronic element has been proposed to be the imprinting box for the mouse gene and although the relevance of this element has yet to be directly demonstrated, methylation has been reported to be essential to maintain allele-specific expression of imprinted genes. Allelic expression analysis of human IGF2R in 70 lymphoblastoid cell lines identified only one line showing monoallelic expression. Thus, in this tissue monoparental methylation of the IGF2R gene does not correlate with allele-specific expression. We also confirm here that the human IGF2R gene is located in an asynchronously replicating chromosomal region, as are all other imprinted genes so far analyzed. The mouse and human IGF2R intronic CpG islands both contain numerous large direct repeats that are methylated following maternal, but not paternal, transmittance. Thus features that attract maternal-specific methylation are conserved between the mouse and human genes. Since these intronic CpG islands share organizational rather than sequence homology, this suggests that secondary DNA structure may play a role in attracting a maternal methylation imprint.

  13. Identification of Cell Type-Specific Differences in Erythropoietin Receptor Signaling in Primary Erythroid and Lung Cancer Cells

    PubMed Central

    Salopiata, Florian; Depner, Sofia; Wäsch, Marvin; Böhm, Martin E.; Mücke, Oliver; Plass, Christoph; Lehmann, Wolf D.; Kreutz, Clemens; Timmer, Jens; Klingmüller, Ursula

    2016-01-01

    Lung cancer, with its most prevalent form non-small-cell lung carcinoma (NSCLC), is one of the leading causes of cancer-related deaths worldwide, and is commonly treated with chemotherapeutic drugs such as cisplatin. Lung cancer patients frequently suffer from chemotherapy-induced anemia, which can be treated with erythropoietin (EPO). However, studies have indicated that EPO not only promotes erythropoiesis in hematopoietic cells, but may also enhance survival of NSCLC cells. Here, we verified that the NSCLC cell line H838 expresses functional erythropoietin receptors (EPOR) and that treatment with EPO reduces cisplatin-induced apoptosis. To pinpoint differences in EPO-induced survival signaling in erythroid progenitor cells (CFU-E, colony forming unit-erythroid) and H838 cells, we combined mathematical modeling with a method for feature selection, the L1 regularization. Utilizing an example model and simulated data, we demonstrated that this approach enables the accurate identification and quantification of cell type-specific parameters. We applied our strategy to quantitative time-resolved data of EPO-induced JAK/STAT signaling generated by quantitative immunoblotting, mass spectrometry and quantitative real-time PCR (qRT-PCR) in CFU-E and H838 cells as well as H838 cells overexpressing human EPOR (H838-HA-hEPOR). The established parsimonious mathematical model was able to simultaneously describe the data sets of CFU-E, H838 and H838-HA-hEPOR cells. Seven cell type-specific parameters were identified that included for example parameters for nuclear translocation of STAT5 and target gene induction. Cell type-specific differences in target gene induction were experimentally validated by qRT-PCR experiments. The systematic identification of pathway differences and sensitivities of EPOR signaling in CFU-E and H838 cells revealed potential targets for intervention to selectively inhibit EPO-induced signaling in the tumor cells but leave the responses in erythroid

  14. De novo CNV analysis implicates specific abnormalities of postsynaptic signalling complexes in the pathogenesis of schizophrenia.

    PubMed

    Kirov, G; Pocklington, A J; Holmans, P; Ivanov, D; Ikeda, M; Ruderfer, D; Moran, J; Chambert, K; Toncheva, D; Georgieva, L; Grozeva, D; Fjodorova, M; Wollerton, R; Rees, E; Nikolov, I; van de Lagemaat, L N; Bayés, A; Fernandez, E; Olason, P I; Böttcher, Y; Komiyama, N H; Collins, M O; Choudhary, J; Stefansson, K; Stefansson, H; Grant, S G N; Purcell, S; Sklar, P; O'Donovan, M C; Owen, M J

    2012-02-01

    A small number of rare, recurrent genomic copy number variants (CNVs) are known to substantially increase susceptibility to schizophrenia. As a consequence of the low fecundity in people with schizophrenia and other neurodevelopmental phenotypes to which these CNVs contribute, CNVs with large effects on risk are likely to be rapidly removed from the population by natural selection. Accordingly, such CNVs must frequently occur as recurrent de novo mutations. In a sample of 662 schizophrenia proband-parent trios, we found that rare de novo CNV mutations were significantly more frequent in cases (5.1% all cases, 5.5% family history negative) compared with 2.2% among 2623 controls, confirming the involvement of de novo CNVs in the pathogenesis of schizophrenia. Eight de novo CNVs occurred at four known schizophrenia loci (3q29, 15q11.2, 15q13.3 and 16p11.2). De novo CNVs of known pathogenic significance in other genomic disorders were also observed, including deletion at the TAR (thrombocytopenia absent radius) region on 1q21.1 and duplication at the WBS (Williams-Beuren syndrome) region at 7q11.23. Multiple de novos spanned genes encoding members of the DLG (discs large) family of membrane-associated guanylate kinases (MAGUKs) that are components of the postsynaptic density (PSD). Two de novos also affected EHMT1, a histone methyl transferase known to directly regulate DLG family members. Using a systems biology approach and merging novel CNV and proteomics data sets, systematic analysis of synaptic protein complexes showed that, compared with control CNVs, case de novos were significantly enriched for the PSD proteome (P=1.72 × 10⁻⁶. This was largely explained by enrichment for members of the N-methyl-D-aspartate receptor (NMDAR) (P=4.24 × 10⁻⁶) and neuronal activity-regulated cytoskeleton-associated protein (ARC) (P=3.78 × 10⁻⁸) postsynaptic signalling complexes. In an analysis of 18 492 subjects (7907 cases and 10 585 controls), case CNVs were

  15. Classification of upper arm EMG signals during object-specific grasp.

    PubMed

    Martelloni, C; Carpaneto, J; Micera, S

    2008-01-01

    Electromyographic (EMG) signals can represent an interesting solution to control artificial hands because they are easy to record and can allow the user to control different robotic systems. However, after limb amputation the 'homologous' muscles are no more available to control the prosthetic device and for this reason complex pattern recognition approaches have to be developed to extract the voluntary commands by the user. This makes the control strategy less natural and acceptable and asks for alternative approaches. At the same time, it has been recently shown that (in monkeys) it is possible to discriminate grasping tasks just analyzing the activation onset/offset of upper limb muscles during the reaching phase. This kind of information can be very interesting because it can allow the development of a natural EMG-based control strategy based on the natural muscular activities selected by the central nervous system. In this paper, preliminary experiments have been carried out in order to verify whether these results can be confirmed also in human beings. In particular, a support vector machine (SVM) based pattern recognition algorithm has been developed and used for the prediction of grip types from the EMG recorded from proximal and distal muscles during reach to grasp movements of three able bodied subjects.

  16. Tissue-Specific Regulation of Gibberellin Signaling Fine-Tunes Arabidopsis Iron-Deficiency Responses.

    PubMed

    Wild, Michael; Davière, Jean-Michel; Regnault, Thomas; Sakvarelidze-Achard, Lali; Carrera, Esther; Lopez Diaz, Isabel; Cayrel, Anne; Dubeaux, Guillaume; Vert, Grégory; Achard, Patrick

    2016-04-18

    Iron is an essential element for most living organisms. Plants acquire iron from the rhizosphere and have evolved different biochemical and developmental responses to adapt to a low-iron environment. In Arabidopsis, FIT encodes a basic helix-loop-helix transcription factor that activates the expression of iron-uptake genes in root epidermis upon iron deficiency. Here, we report that the gibberellin (GA)-signaling DELLA repressors contribute substantially in the adaptive responses to iron-deficient conditions. When iron availability decreases, DELLAs accumulate in the root meristem, thereby restraining root growth, while being progressively excluded from epidermal cells in the root differentiation zone. Such DELLA exclusion from the site of iron acquisition relieves FIT from DELLA-dependent inhibition and therefore promotes iron uptake. Consistent with this mechanism, expression of a non-GA-degradable DELLA mutant protein in root epidermis interferes with iron acquisition. Hence, spatial distribution of DELLAs in roots is essential to fine-tune the adaptive responses to iron availability.

  17. The plant-specific SR45 protein negatively regulates glucose and ABA signaling during early seedling development in Arabidopsis.

    PubMed

    Carvalho, Raquel Fonseca; Carvalho, Sofia Domingues; Duque, Paula

    2010-10-01

    The plant-specific SR45 belongs to the highly conserved family of serine/arginine-rich (SR) proteins, which play key roles in precursor-mRNA splicing and other aspects of RNA metabolism. An Arabidopsis (Arabidopsis thaliana) loss-of-function mutant, sr45-1, displays pleiotropic phenotypes, such as defects in flower and leaf morphology, root growth, and flowering time. Here, we show that the sr45-1 mutation confers hypersensitivity to glucose (Glc) during early seedling growth in Arabidopsis. Unlike wild-type plants, the sr45-1 mutant displays impaired cotyledon greening and expansion as well as reduced hypocotyl elongation of dark-grown seedlings when grown in the presence of low (3%) Glc concentrations. In addition, SR45 is involved in the control of Glc-responsive gene expression, as the mutant displays enhanced repression of photosynthetic and nitrogen metabolism genes and overinduction of starch and anthocyanin biosynthesis genes. Like many other sugar response mutants, sr45-1 also shows hypersensitivity to abscisic acid (ABA) but appears to be unaffected in ethylene signaling. Importantly, the sr45-1 mutant shows enhanced ability to accumulate ABA in response to Glc, and the ABA biosynthesis inhibitor fluridone partially rescues the sugar-mediated growth arrest. Moreover, three ABA biosynthesis genes and two key ABA signaling genes, ABI3 and ABI5, are markedly overinduced by Glc in sr45-1. These results provide evidence that the SR45 protein defines a novel player in plant sugar response that negatively regulates Glc signaling during early seedling development by down-regulating both Glc-specific ABA accumulation and ABA biosynthesis and signaling gene expression. PMID:20699397

  18. A computation using mutually exclusive processing is sufficient to identify specific Hedgehog signaling components

    PubMed Central

    Spratt, Spencer J.

    2013-01-01

    A system of more than one part can be deciphered by observing differences between the parts. A simple way to do this is by recording something absolute displaying a trait in one part and not in another: in other words, mutually exclusive computation. Conditional directed expression in vivo offers processing in more than one part of the system giving increased computation power for biological systems analysis. Here, I report the consideration of these aspects in the development of an in vivo screening assay that appears sufficient to identify components specific to a system. PMID:24391661

  19. RED1 is necessary for phytochrome B-mediated red light-specific signal transduction in Arabidopsis.

    PubMed Central

    Wagner, D; Hoecker, U; Quail, P H

    1997-01-01

    Seedlings of a transgenic Arabidopsis line (ABO) that overexpresses phytochrome B (phyB) display enhanced deetiolation specifically in red light. To identify genetic loci necessary for phytochrome signal transduction in red light, we chemically mutagenized ABO seeds and screened M2 seedlings for revertants of the enhanced deetiolation response. One recessive, red light-specific extragenic revertant, designated red1, was isolated. The mutant phenotype was expressed in the original ABO background as well as in the nontransgenic Nossen (No-0) progenitor background. red1 is also deficient in several other aspects of red light-induced responses known to be mediated by phyB, such as inhibition of petiole elongation and the shade avoidance response. red1 was mapped to the bottom of chromosome 4 at a position distinct from all known photoreceptor loci. Together with complementation analysis, the data show that red1 is a novel photomorphogenic mutant. The evidence suggests that red1 represents a putative phytochrome signal transduction mutant potentially specific to the phyB pathway. PMID:9165750

  20. Dact genes are chordate specific regulators at the intersection of Wnt and Tgf-β signaling pathways

    PubMed Central

    2014-01-01

    Background Dacts are multi-domain adaptor proteins. They have been implicated in Wnt and Tgfβ signaling and serve as a nodal point in regulating many cellular activities. Dact genes have so far only been identified in bony vertebrates. Also, the number of Dact genes in a given species, the number and roles of protein motifs and functional domains, and the overlap of gene expression domains are all not clear. To address these problems, we have taken an evolutionary approach, screening for Dact genes in the animal kingdom and establishing their phylogeny and the synteny of Dact loci. Furthermore, we performed a deep analysis of the various Dact protein motifs and compared the expression patterns of different Dacts. Results Our study identified previously not recognized dact genes and showed that they evolved late in the deuterostome lineage. In gnathostomes, four Dact genes were generated by the two rounds of whole genome duplication in the vertebrate ancestor, with Dact1/3 and Dact2/4, respectively, arising from the two genes generated during the first genome duplication. In actinopterygians, a further dact4r gene arose from retrotranscription. The third genome duplication in the teleost ancestor, and subsequent gene loss in most gnathostome lineages left extant species with a subset of Dact genes. The distribution of functional domains suggests that the ancestral Dact function lied with Wnt signaling, and a role in Tgfβ signaling may have emerged with the Dact2/4 ancestor. Motif reduction, in particular in Dact4, suggests that this protein may counteract the function of the other Dacts. Dact genes were expressed in both distinct and overlapping domains, suggesting possible combinatorial function. Conclusions The gnathostome Dact gene family comprises four members, derived from a chordate-specific ancestor. The ability to control Wnt signaling seems to be part of the ancestral repertoire of Dact functions, while the ability to inhibit Tgfβ signaling and to carry

  1. The Mediator Kinase Module Restrains Epidermal Growth Factor Receptor Signaling and Represses Vulval Cell Fate Specification in Caenorhabditis elegans.

    PubMed

    Grants, Jennifer M; Ying, Lisa T L; Yoda, Akinori; You, Charlotte C; Okano, Hideyuki; Sawa, Hitoshi; Taubert, Stefan

    2016-02-01

    Cell signaling pathways that control proliferation and determine cell fates are tightly regulated to prevent developmental anomalies and cancer. Transcription factors and coregulators are important effectors of signaling pathway output, as they regulate downstream gene programs. In Caenorhabditis elegans, several subunits of the Mediator transcriptional coregulator complex promote or inhibit vulva development, but pertinent mechanisms are poorly defined. Here, we show that Mediator's dissociable cyclin dependent kinase 8 (CDK8) module (CKM), consisting of cdk-8, cic-1/Cyclin C, mdt-12/dpy-22, and mdt-13/let-19, is required to inhibit ectopic vulval cell fates downstream of the epidermal growth factor receptor (EGFR)-Ras-extracellular signal-regulated kinase (ERK) pathway. cdk-8 inhibits ectopic vulva formation by acting downstream of mpk-1/ERK, cell autonomously in vulval cells, and in a kinase-dependent manner. We also provide evidence that the CKM acts as a corepressor for the Ets-family transcription factor LIN-1, as cdk-8 promotes transcriptional repression by LIN-1. In addition, we find that CKM mutation alters Mediator subunit requirements in vulva development: the mdt-23/sur-2 subunit, which is required for vulva development in wild-type worms, is dispensable for ectopic vulva formation in CKM mutants, which instead display hallmarks of unrestrained Mediator tail module activity. We propose a model whereby the CKM controls EGFR-Ras-ERK transcriptional output by corepressing LIN-1 and by fine tuning Mediator specificity, thus balancing transcriptional repression vs. activation in a critical developmental signaling pathway. Collectively, these data offer an explanation for CKM repression of EGFR signaling output and ectopic vulva formation and provide the first evidence of Mediator CKM-tail module subunit crosstalk in animals. PMID:26715664

  2. SPEAKING IN LIGHT - Jupiter radio signals as deflections of light-emitting electron beams in a vacuum chamber

    NASA Astrophysics Data System (ADS)

    Petrovic, K.

    2015-10-01

    Light emitting electron beam generated in a vacuum chamber is used as a medium for visualizing Jupiter's electromagnetic radiation. Dual dipole array antenna is receiving HF radio signals that are next amplified to radiate a strong electromagnetic field capable of influencing the propagation of electron beam in plasma. Installation aims to provide a platform for observing the characteristics of light emitting beam in 3D, as opposed to the experiments with cathode ray tubes in 2-dimensional television screens. Gas giant 'speaking' to us by radio waves bends the light in the tube, allowing us to see and hear the messages of Jupiter - God of light and sky.

  3. Molecular dissection of egg fertilization signaling with the aid of tyrosine kinase-specific inhibitor and activator strategies.

    PubMed

    Sato, Ken-ichi; Iwasaki, Tetsushi; Hirahara, Shino; Nishihira, Yusuke; Fukami, Yasuo

    2004-03-11

    Fertilization is triggered by sperm-egg interaction and fusion that initiate a transient rise(s) in the free intracellular calcium ([Ca(2+)](i)) that is responsible for a series of biochemical and cell biological events, so-called "egg activation". Calcium-dependent egg activation leads to the initiation of developmental program that culminates in the birth of individuals. A growing body of knowledge has uncovered the molecular mechanisms underlying sperm-induced transient [Ca(2+)](i) increase(s) to some extent; namely, in most animals so far studied, a second messenger inositol 1,4,5-trisphosphate (IP(3)) seems to play a pivotal role in inducing [Ca(2+)](i) transient(s) at fertilization. However, signaling mechanisms used by sperm to initiate IP(3)-[Ca(2+)](i) transient pathway have not been elucidated. To approach this problem, we have employed African clawed frog, Xenopus laevis, as a model animal and conducted experiments designed specifically to determine the role of the Src family protein-tyrosine kinases (SFKs or Src family PTKs) in the sperm-induced egg activation. This review compiles information about the use of PTK-specific inhibitors and activators for analyzing signal transduction events in egg fertilization. Specifically, we focus on molecular identification of Xenopus Src and the signaling mechanism of the Src-dependent egg activation that has been established recently. We also summarize recent advances in understanding the role of the Src family kinases in egg fertilization of other model organisms, and discuss future directions of the field.

  4. Physical therapists’ treatment choices for non-specific low back pain in Florida: an electronic survey

    PubMed Central

    Ladeira, Carlos E; Samuel Cheng, M; Hill, Cheryl J

    2015-01-01

    Objectives: No study has described low back pain (LBP) treatment choices among physical therapists (PTs) in the United States (US) in the new millennium. Intervention for LBP in the new millennium is largely based on evidence-based practice (EBP) recommendations. The purpose of this study was twofold: (a) to describe PTs' preferences for treating acute and subacute non-specific LBP in Florida and to compare these preferences to EBP guideline recommendations and (b) to compare outpatient musculoskeletal therapist (MSPT) choices for management of acute and subacute LBP to non-outpatient musculoskeletal therapist (NMSPT) choices. Methods: The data were collected with an electronic survey. Study participants selected treatment choices for acute and subacute LBP clinical vignettes. Results: A total of 327 PTs participated in the study, of which 128 worked in outpatient musculoskeletal settings. The most common treatment choices for acute and subacute LBP were home exercise program, exercise in the clinic, back care education, joint mobilization, ice/heat, and interferential current. The EBP adherence rate for acute LBP was 30% for MSPTs and 15% for NMSPTs. Thirty-seven percent (37%) of MSPTs and 30% of NMSPTs adhered to EBP guidelines for subacute LBP. Discussion: The EBP adherence rate for management of acute and subacute LBP was low. Spinal manipulation was underutilized for management of acute LBP, and passive therapeutic procedures were overutilized for subacute LBP. Physical Therapy schools and professional associations should reemphasize the benefits of spinal manipulation to manage non-specific acute LBP and active interventional procedures to manage subacute LBP. PMID:26109832

  5. Modeling Analysis of Signal Sensitivity and Specificity by Vibrio fischeri LuxR Variants.

    PubMed

    Colton, Deanna M; Stabb, Eric V; Hagen, Stephen J

    2015-01-01

    The LuxR protein of the bacterium Vibrio fischeri belongs to a family of transcriptional activators that underlie pheromone-mediated signaling by responding to acyl-homoserine lactones (-HSLs) or related molecules. V. fischeri produces two acyl-HSLs, N-3-oxo-hexanoyl-HSL (3OC6-HSL) and N-octanoyl-HSL (C8-HSL), each of which interact with LuxR to facilitate its binding to a "lux box" DNA sequence, thereby enabling LuxR to activate transcription of the lux operon responsible for bioluminescence. We have investigated the HSL sensitivity of four different variants of V. fischeri LuxR: two derived from wild-type strains ES114 and MJ1, and two derivatives of LuxRMJ1 generated by directed evolution. For each LuxR variant, we measured the bioluminescence induced by combinations of C8-HSL and 3OC6-HSL. We fit these data to a model in which the two HSLs compete with each other to form multimeric LuxR complexes that directly interact with lux to activate bioluminescence. The model reproduces the observed effects of HSL combinations on the bioluminescence responses directed by LuxR variants, including competition and non-monotonic responses to C8-HSL and 3OC6-HSL. The analysis yields robust estimates for the underlying dissociation constants and cooperativities (Hill coefficients) of the LuxR-HSL complexes and their affinities for the lux box. It also reveals significant differences in the affinities of LuxRMJ1 and LuxRES114 for 3OC6-HSL. Further, LuxRMJ1 and LuxRES114 differed sharply from LuxRs retrieved by directed evolution in the cooperativity of LuxR-HSL complex formation and the affinity of these complexes for lux. These results show how computational modeling of in vivo experimental data can provide insight into the mechanistic consequences of directed evolution.

  6. Stretchable Multichannel Electromyography Sensor Array Covering Large Area for Controlling Home Electronics with Distinguishable Signals from Multiple Muscles.

    PubMed

    Kim, Namyun; Lim, Taehoon; Song, Kwangsun; Yang, Sung; Lee, Jongho

    2016-08-17

    Physiological signals provide important information for biomedical applications and, more recently, in the form of wearable electronics for active interactions between bodies and external environments. Multiple physiological sensors are often required to map distinct signals from multiple points over large areas for more diverse applications. In this paper, we present a reusable, multichannel, surface electromyography (EMG) sensor array that covers multiple muscles over relatively large areas, with compliant designs that provide different levels of stiffness for repetitive uses, without backing layers. Mechanical and electrical characteristics along with distinct measurements from different muscles demonstrate the feasibility of the concept. The results should be useful to actively control devices in the environment with one array of wearable sensors, as demonstrated with home electronics. PMID:27500864

  7. Stretchable Multichannel Electromyography Sensor Array Covering Large Area for Controlling Home Electronics with Distinguishable Signals from Multiple Muscles.

    PubMed

    Kim, Namyun; Lim, Taehoon; Song, Kwangsun; Yang, Sung; Lee, Jongho

    2016-08-17

    Physiological signals provide important information for biomedical applications and, more recently, in the form of wearable electronics for active interactions between bodies and external environments. Multiple physiological sensors are often required to map distinct signals from multiple points over large areas for more diverse applications. In this paper, we present a reusable, multichannel, surface electromyography (EMG) sensor array that covers multiple muscles over relatively large areas, with compliant designs that provide different levels of stiffness for repetitive uses, without backing layers. Mechanical and electrical characteristics along with distinct measurements from different muscles demonstrate the feasibility of the concept. The results should be useful to actively control devices in the environment with one array of wearable sensors, as demonstrated with home electronics.

  8. Electronic specific heat enhancement in the half-metallic ferromagnet Cro2 explained by Fermi Liquid Theory

    NASA Astrophysics Data System (ADS)

    Chura, Raul; Bedell, Kevin

    2007-03-01

    Available data on the electronic specific heat of the half-metallic ferromagnet (HMF) CrO2, show that the obtained experimental values are systematically greater than the corresponding theoretical ones calculated through various band theory methods. This discrepancy is due to the presence of many-electron correlation effects (spin fluctuations, strong electron-magnon scattering) which are not taken into account in the band theory calculations. A renormalization of the band theory results is therefore needed to account for the observed enhancement in the value of the specific heat. A microscopic many-electron approach has been proposed and explains the referred enhancement in terms of non-quasiparticle effects. It has been argued that Fermi liquid theory is not sufficient to provide the appropriate renormalization able to explain the observed enhancement in the electronic specific heat of HMFs. Contrary to this statement, we have shown that the introduction of a spin-dependent density of states, in the framework of the Fermi liquid theory for spin polarized systems, gives place to a renormalization which, indeed, provides a reasonable account of the observed enhancement in the electronic specific heat of the HMF CrO2.

  9. Thermal Radiometer Signal Processing Using Radiation Hard CMOS Application Specific Integrated Circuits for Use in Harsh Planetary Environments

    NASA Technical Reports Server (NTRS)

    Quilligan, G.; DuMonthier, J.; Aslam, S.; Lakew, B.; Kleyner, I.; Katz, R.

    2015-01-01

    Thermal radiometers such as proposed for the Europa Clipper flyby mission require low noise signal processing for thermal imaging with immunity to Total Ionizing Dose (TID) and Single Event Latchup (SEL). Described is a second generation Multi- Channel Digitizer (MCD2G) Application Specific Integrated Circuit (ASIC) that accurately digitizes up to 40 thermopile pixels with greater than 50 Mrad (Si) immunity TID and 174 MeV-sq cm/mg SEL. The MCD2G ASIC uses Radiation Hardened By Design (RHBD) techniques with a 180 nm CMOS process node.

  10. Thermal Radiometer Signal Processing using Radiation Hard CMOS Application Specific Integrated Circuits for use in Harsh Planetary Environments

    NASA Astrophysics Data System (ADS)

    Quilligan, G.; DuMonthier, J.; Aslam, S.; Lakew, B.; Kleyner, I.; Katz, R.

    2015-10-01

    Thermal radiometers such as proposed for the Europa Clipper flyby mission [1] require low noise signal processing for thermal imaging with immunity to Total Ionizing Dose (TID) and Single Event Latchup (SEL). Described is a second generation Multi- Channel Digitizer (MCD2G) Application Specific Integrated Circuit (ASIC) that accurately digitizes up to 40 thermopile pixels with greater than 50 Mrad (Si) immunity TID and 174 MeV-cm2/mg SEL. The MCD2G ASIC uses Radiation Hardened By Design (RHBD) techniques with a 180 nm CMOS process node.

  11. Uncovering Global SUMOylation Signaling Networks in a Site-Specific Manner

    PubMed Central

    Hendriks, Ivo A.; D’Souza, Rochelle C.J.; Yang, Bing; Verlaan-de Vries, Matty; Mann, Matthias; Vertegaal, Alfred C.O.

    2014-01-01

    SUMOylation is a reversible post-translational modification essential for genome stability. Using high-resolution mass spectrometry, we have studied global SUMOylation in human cells and in a site-specific manner, identifying a total of over 4,300 SUMOylation sites in over 1,600 proteins. Moreover, for the first time in excess of 1,000 SUMOylation sites were identified under standard growth conditions. SUMOylation dynamics were quantitatively studied in response to SUMO protease inhibition, proteasome inhibition and heat shock. A considerable amount of SUMOylated lysines have previously been reported to be ubiquitylated, acetylated or methylated, indicating crosstalk between SUMO and other post-translational modifications. We identified 70 phosphorylation and 4 acetylation events in close proximity to SUMOylation sites, and provide evidence for acetylation-dependent SUMOylation of endogenous histone H3. SUMOylation regulates target proteins involved in all nuclear processes including transcription, DNA repair, chromatin remodeling, pre-mRNA splicing and ribosome assembly. PMID:25218447

  12. 36 CFR 1235.50 - What specifications and standards for transfer apply to electronic records?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Language (SGML) or XML tags. (e) Electronic mail, scanned images of textual records, portable document... standards for transfer apply to electronic records? 1235.50 Section 1235.50 Parks, Forests, and Public... and standards for transfer apply to electronic records? (a) General. (1) Agencies must...

  13. Combined fluorescent and electron microscopic imaging unveils the specific properties of two classes of meiotic crossovers.

    PubMed

    Anderson, Lorinda K; Lohmiller, Leslie D; Tang, Xiaomin; Hammond, D Boyd; Javernick, Lauren; Shearer, Lindsay; Basu-Roy, Sayantani; Martin, Olivier C; Falque, Matthieu

    2014-09-16

    Crossovers (COs) shuffle genetic information and allow balanced segregation of homologous chromosomes during the first division of meiosis. In several organisms, mutants demonstrate that two molecularly distinct pathways produce COs. One pathway produces class I COs that exhibit interference (lowered probability of nearby COs), and the other pathway produces class II COs with little or no interference. However, the relative contributions, genomic distributions, and interactions of these two pathways are essentially unknown in nonmutant organisms because marker segregation only indicates that a CO has occurred, not its class type. Here, we combine the efficiency of light microscopy for revealing cellular functions using fluorescent probes with the high resolution of electron microscopy to localize and characterize COs in the same sample of meiotic pachytene chromosomes from wild-type tomato. To our knowledge, for the first time, every CO along each chromosome can be identified by class to unveil specific characteristics of each pathway. We find that class I and II COs have different recombination profiles along chromosomes. In particular, class II COs, which represent about 18% of all COs, exhibit no interference and are disproportionately represented in pericentric heterochromatin, a feature potentially exploitable in plant breeding. Finally, our results demonstrate that the two pathways are not independent because there is interference between class I and II COs. PMID:25197066

  14. Small signal modeling of high electron mobility transistors on silicon and silicon carbide substrate with consideration of substrate loss mechanism

    NASA Astrophysics Data System (ADS)

    Sahoo, A. K.; Subramani, N. K.; Nallatamby, J. C.; Sylvain, L.; Loyez, C.; Quere, R.; Medjdoub, F.

    2016-01-01

    In this paper, we present a comparative study on small-signal modeling of AlN/GaN/AlGaN double hetero-structure high electron mobility transistors (HEMTs) grown on silicon (Si) and silicon carbide (SiC) substrate. The traditional small signal equivalent circuit model is modified to take into account the transmission loss mechanism of coplanar waveguide (CPW) line which cannot be neglected at high frequencies. CPWs and HEMTs-on-AlN/GaN/AlGaN epitaxial layers are fabricated on both the Si and SiC substrates. S-parameter measurements at room temperature are performed over the frequency range from 0.5 GHz to 40 GHz. Transmission loss of CPW lines are modeled with a distributed transmission line (TL) network and an equivalent circuit model is included in the small-signal transistor model topology. Measurements and simulations are compared and found to be in good agreement.

  15. Religion and action control: Faith-specific modulation of the Simon effect but not Stop-Signal performance.

    PubMed

    Hommel, Bernhard; Colzato, Lorenza S; Scorolli, Claudia; Borghi, Anna M; van den Wildenberg, Wery P M

    2011-08-01

    Previous findings suggest that religion has a specific impact on attentional processes. Here we show that religion also affects action control. Experiment 1 compared Dutch Calvinists and Dutch atheists, matched for age, sex, intelligence, education, and cultural and socio-economic background, and Experiment 2 compared Italian Catholics with matched Italian seculars. As expected, Calvinists showed a smaller and Catholics a larger Simon effect than nonbelievers, while performance of the groups was comparable in the Stop-Signal task. This pattern suggests that religions emphasizing individualism or collectivism affects action control in specific ways, presumably by inducing chronic biases towards a more "exclusive" or "inclusive" style of decision-making. Interestingly, there was no evidence that religious practice affects inhibitory skills.

  16. Cell Density Sensing Alters TGF-β Signaling in a Cell-Type-Specific Manner, Independent from Hippo Pathway Activation

    PubMed Central

    Nallet-Staub, Flore; Yin, Xueqian; Gilbert, Cristèle; Marsaud, Véronique; Ben Mimoun, Saber; Javelaud, Delphine; Leof, Edward B.; Mauviel, Alain

    2015-01-01

    SUMMARY Cell-cell contacts inhibit cell growth and proliferation in part by activating the Hippo pathway that drives the phosphorylation and nuclear exclusion of the transcriptional coactivators YAP and TAZ. Cell density and Hippo signaling have also been reported to block transforming growth factor β (TGF-β) responses, based on the ability of phospho-YAP/TAZ to sequester TGF-β-activated SMAD complexes in the cytoplasm. Herein, we provide evidence that epithelial cell polarization interferes with TGF-β signaling well upstream and independent of cytoplasmic YAP/TAZ. Rather, polarized basolateral presentation of TGF-β receptors I and II deprives apically delivered TGF-β of access to its receptors. Basolateral ligand delivery nonetheless remains entirely effective to induce TGF-β responses. These data demonstrate that cell-type-specific inhibition of TGF-β signaling by cell density is restricted to polarized epithelial cells and reflects the polarized distribution of TGF-β receptors, which thus affects SMAD activation irrespective of Hippo pathway activation. PMID:25758862

  17. From contraction to gene expression: nanojunctions of the sarco/endoplasmic reticulum deliver site- and function-specific calcium signals.

    PubMed

    Evans, A Mark; Fameli, Nicola; Ogunbayo, Oluseye A; Duan, Jingxian; Navarro-Dorado, Jorge

    2016-08-01

    Calcium signals determine, for example, smooth muscle contraction and changes in gene expression. How calcium signals select for these processes is enigmatic. We build on the "panjunctional sarcoplasmic reticulum" hypothesis, describing our view that different calcium pumps and release channels, with different kinetics and affinities for calcium, are strategically positioned within nanojunctions of the SR and help demarcate their respective cytoplasmic nanodomains. SERCA2b and RyR1 are preferentially targeted to the sarcoplasmic reticulum (SR) proximal to the plasma membrane (PM), i.e., to the superficial buffer barrier formed by PM-SR nanojunctions, and support vasodilation. In marked contrast, SERCA2a may be entirely restricted to the deep, perinuclear SR and may supply calcium to this sub-compartment in support of vasoconstriction. RyR3 is also preferentially targeted to the perinuclear SR, where its clusters associate with lysosome-SR nanojunctions. The distribution of RyR2 is more widespread and extends from this region to the wider cell. Therefore, perinuclear RyR3s most likely support the initiation of global calcium waves at L-SR junctions, which subsequently propagate by calcium-induced calcium release via RyR2 in order to elicit contraction. Data also suggest that unique SERCA and RyR are preferentially targeted to invaginations of the nuclear membrane. Site- and function-specific calcium signals may thus arise to modulate stimulus-response coupling and transcriptional cascades.

  18. Lineage-specific effects of Notch/Numb signaling in post-embryonic development of the Drosophila brain.

    PubMed

    Lin, Suewei; Lai, Sen-Lin; Yu, Huang-Hsiang; Chihara, Takahiro; Luo, Liqun; Lee, Tzumin

    2010-01-01

    Numb can antagonize Notch signaling to diversify the fates of sister cells. We report here that paired sister cells acquire different fates in all three Drosophila neuronal lineages that make diverse types of antennal lobe projection neurons (PNs). Only one in each pair of postmitotic neurons survives into the adult stage in both anterodorsal (ad) and ventral (v) PN lineages. Notably, Notch signaling specifies the PN fate in the vPN lineage but promotes programmed cell death in the missing siblings in the adPN lineage. In addition, Notch/Numb-mediated binary sibling fates underlie the production of PNs and local interneurons from common precursors in the lAL lineage. Furthermore, Numb is needed in the lateral but not adPN or vPN lineages to prevent the appearance of ectopic neuroblasts and to ensure proper self-renewal of neural progenitors. These lineage-specific outputs of Notch/Numb signaling show that a universal mechanism of binary fate decision can be utilized to govern diverse neural sibling differentiations.

  19. RNA helicase HEL-1 promotes longevity by specifically activating DAF-16/FOXO transcription factor signaling in Caenorhabditis elegans.

    PubMed

    Seo, Mihwa; Seo, Keunhee; Hwang, Wooseon; Koo, Hee Jung; Hahm, Jeong-Hoon; Yang, Jae-Seong; Han, Seong Kyu; Hwang, Daehee; Kim, Sanguk; Jang, Sung Key; Lee, Yoontae; Nam, Hong Gil; Lee, Seung-Jae V

    2015-08-01

    The homeostatic maintenance of the genomic DNA is crucial for regulating aging processes. However, the role of RNA homeostasis in aging processes remains unknown. RNA helicases are a large family of enzymes that regulate the biogenesis and homeostasis of RNA. However, the functional significance of RNA helicases in aging has not been explored. Here, we report that a large fraction of RNA helicases regulate the lifespan of Caenorhabditis elegans. In particular, we show that a DEAD-box RNA helicase, helicase 1 (HEL-1), promotes longevity by specifically activating the DAF-16/forkhead box O (FOXO) transcription factor signaling pathway. We find that HEL-1 is required for the longevity conferred by reduced insulin/insulin-like growth factor 1 (IGF-1) signaling (IIS) and is sufficient for extending lifespan. We further show that the expression of HEL-1 in the intestine and neurons contributes to longevity. HEL-1 enhances the induction of a large fraction of DAF-16 target genes. Thus, the RNA helicase HEL-1 appears to promote longevity in response to decreased IIS as a transcription coregulator of DAF-16. Because HEL-1 and IIS are evolutionarily well conserved, a similar mechanism for longevity regulation via an RNA helicase-dependent regulation of FOXO signaling may operate in mammals, including humans. PMID:26195740

  20. RNA helicase HEL-1 promotes longevity by specifically activating DAF-16/FOXO transcription factor signaling in Caenorhabditis elegans.

    PubMed

    Seo, Mihwa; Seo, Keunhee; Hwang, Wooseon; Koo, Hee Jung; Hahm, Jeong-Hoon; Yang, Jae-Seong; Han, Seong Kyu; Hwang, Daehee; Kim, Sanguk; Jang, Sung Key; Lee, Yoontae; Nam, Hong Gil; Lee, Seung-Jae V

    2015-08-01

    The homeostatic maintenance of the genomic DNA is crucial for regulating aging processes. However, the role of RNA homeostasis in aging processes remains unknown. RNA helicases are a large family of enzymes that regulate the biogenesis and homeostasis of RNA. However, the functional significance of RNA helicases in aging has not been explored. Here, we report that a large fraction of RNA helicases regulate the lifespan of Caenorhabditis elegans. In particular, we show that a DEAD-box RNA helicase, helicase 1 (HEL-1), promotes longevity by specifically activating the DAF-16/forkhead box O (FOXO) transcription factor signaling pathway. We find that HEL-1 is required for the longevity conferred by reduced insulin/insulin-like growth factor 1 (IGF-1) signaling (IIS) and is sufficient for extending lifespan. We further show that the expression of HEL-1 in the intestine and neurons contributes to longevity. HEL-1 enhances the induction of a large fraction of DAF-16 target genes. Thus, the RNA helicase HEL-1 appears to promote longevity in response to decreased IIS as a transcription coregulator of DAF-16. Because HEL-1 and IIS are evolutionarily well conserved, a similar mechanism for longevity regulation via an RNA helicase-dependent regulation of FOXO signaling may operate in mammals, including humans.

  1. Extracellular matrix-dependent tissue-specific gene expression in mammary epithelial cells requires both physical and biochemical signal transduction

    SciTech Connect

    Roskelley, C.D.; Desprez, P.Y.; Bissell, M.J. )

    1994-12-20

    Extracellular matrix (ECM) profoundly influences the growth and differentiation of the mammary gland epithelium, both in culture and in vivo. Utilizing a clonal population of mouse mammary epithelial cells that absolutely requires an exogenous ECM for function, we developed a rapid assay to study signal transduction by ECM. Two components of the cellular response to a basement membrane overlay that result in the expression of the milk protein [beta]-casein were defined. The first component of this response involves a rounding and clustering of the cells that can be physically mimicked by plating the cells on a nonadhesive substratum. The second component is biochemical in nature, and it is associated with [beta][sub 1] integrin clustering and increased tyrosine phosphorylation. The second component is initiated in a morphology-independent manner, but the proper translation of this biochemical signal into a functional response requires cell rounding and cell clustering. Thus, physical and biochemical signal transduction events contribute to the ECM-dependent regulation of tissue-specific gene expression in mouse mammary epithelial cells. 44 refs., 6 figs.

  2. Delay correction model for estimating bus emissions at signalized intersections based on vehicle specific power distributions.

    PubMed

    Song, Guohua; Zhou, Xixi; Yu, Lei

    2015-05-01

    The intersection is one of the biggest emission points for buses and also the high exposure site for people. Several traffic performance indexes have been developed and widely used for intersection evaluations. However, few studies have focused on the relationship between these indexes and emissions at intersections. This paper intends to propose a model that relates emissions to the two commonly used measures of effectiveness (i.e. delay time and number of stops) by using bus activity data and emission data at intersections. First, with a large number of field instantaneous emission data and corresponding activity data collected by the Portable Emission Measurement System (PEMS), emission rates are derived for different vehicle specific power (VSP) bins. Then, 2002 sets of trajectory data, an equivalent of about 140,000 sets of second-by-second activity data, are obtained from Global Position Systems (GPSs)-equipped diesel buses in Beijing. The delay and the emission factors of each trajectory are estimated. Then, by using baseline emission factors for two types of intersections, e.g. the Arterial @ Arterial Intersection and the Arterial @ Collector, delay correction factors are calculated for the two types of intersections at different congestion levels. Finally, delay correction models are established for adjusting emission factors for each type of intersections and different numbers of stops. A comparative analysis between estimated and field emission factors demonstrates that the delay correction model is reliable.

  3. Delay correction model for estimating bus emissions at signalized intersections based on vehicle specific power distributions.

    PubMed

    Song, Guohua; Zhou, Xixi; Yu, Lei

    2015-05-01

    The intersection is one of the biggest emission points for buses and also the high exposure site for people. Several traffic performance indexes have been developed and widely used for intersection evaluations. However, few studies have focused on the relationship between these indexes and emissions at intersections. This paper intends to propose a model that relates emissions to the two commonly used measures of effectiveness (i.e. delay time and number of stops) by using bus activity data and emission data at intersections. First, with a large number of field instantaneous emission data and corresponding activity data collected by the Portable Emission Measurement System (PEMS), emission rates are derived for different vehicle specific power (VSP) bins. Then, 2002 sets of trajectory data, an equivalent of about 140,000 sets of second-by-second activity data, are obtained from Global Position Systems (GPSs)-equipped diesel buses in Beijing. The delay and the emission factors of each trajectory are estimated. Then, by using baseline emission factors for two types of intersections, e.g. the Arterial @ Arterial Intersection and the Arterial @ Collector, delay correction factors are calculated for the two types of intersections at different congestion levels. Finally, delay correction models are established for adjusting emission factors for each type of intersections and different numbers of stops. A comparative analysis between estimated and field emission factors demonstrates that the delay correction model is reliable. PMID:25659309

  4. Retinoid-signaling in progenitors controls specification and regeneration of the urothelium

    PubMed Central

    Reiley, Maia; Laufer, Ed; Metzger, Daniel; Liang, Fengxia; Liao, Yi; Sun, Tung-Tien; Aronow, Bruce; Rosen, Roni; Mauney, Josh; Adam, Rosalyn; Rosselot, Carolina; Van Batavia, Jason; McMahon, Andrew; McMahon, Jill; Guo, Jin-Jin; Mendelsohn, Cathy

    2013-01-01

    The urothelium is a stratified epithelium that prevents exchange of water and toxic substances between the urinary tract and blood. It is composed of Keratin-5-expressing-basal-cells (K5-BCs), intermediate cells and superficial cells specialized for synthesis and transport of uroplakins that assemble into the apical barrier. K5-BCs are considered to be a progenitor cell type in the urothelium and other stratified epithelia. Fate mapping studies however, reveal that P-cells, a transient population, are urothelial progenitors in the embryo, intermediate cells are superficial cell progenitors in the adult regenerating urothelium, and K5-BCs are a distinct lineage. Our studies indicate that retinoids, potent regulators of ES cells and other progenitors, are also required in P-cells and intermediate cells for their specification. These observations have important implications for tissue engineering and repair, and ultimately, may lead to treatments that prevent loss of the urothelial barrier, a major cause of voiding dysfunction and bladder pain syndrome. PMID:23993789

  5. Electronic connection between the quinone and cytochrome C redox pools and its role in regulation of mitochondrial electron transport and redox signaling.

    PubMed

    Sarewicz, Marcin; Osyczka, Artur

    2015-01-01

    Mitochondrial respiration, an important bioenergetic process, relies on operation of four membranous enzymatic complexes linked functionally by mobile, freely diffusible elements: quinone molecules in the membrane and water-soluble cytochromes c in the intermembrane space. One of the mitochondrial complexes, complex III (cytochrome bc1 or ubiquinol:cytochrome c oxidoreductase), provides an electronic connection between these two diffusible redox pools linking in a fully reversible manner two-electron quinone oxidation/reduction with one-electron cytochrome c reduction/oxidation. Several features of this homodimeric enzyme implicate that in addition to its well-defined function of contributing to generation of proton-motive force, cytochrome bc1 may be a physiologically important point of regulation of electron flow acting as a sensor of the redox state of mitochondria that actively responds to changes in bioenergetic conditions. These features include the following: the opposing redox reactions at quinone catalytic sites located on the opposite sides of the membrane, the inter-monomer electronic connection that functionally links four quinone binding sites of a dimer into an H-shaped electron transfer system, as well as the potential to generate superoxide and release it to the intermembrane space where it can be engaged in redox signaling pathways. Here we highlight recent advances in understanding how cytochrome bc1 may accomplish this regulatory physiological function, what is known and remains unknown about catalytic and side reactions within the quinone binding sites and electron transfers through the cofactor chains connecting those sites with the substrate redox pools. We also discuss the developed molecular mechanisms in the context of physiology of mitochondria.

  6. Electronic Connection Between the Quinone and Cytochrome c Redox Pools and Its Role in Regulation of Mitochondrial Electron Transport and Redox Signaling

    PubMed Central

    Sarewicz, Marcin; Osyczka, Artur

    2015-01-01

    Mitochondrial respiration, an important bioenergetic process, relies on operation of four membranous enzymatic complexes linked functionally by mobile, freely diffusible elements: quinone molecules in the membrane and water-soluble cytochromes c in the intermembrane space. One of the mitochondrial complexes, complex III (cytochrome bc1 or ubiquinol:cytochrome c oxidoreductase), provides an electronic connection between these two diffusible redox pools linking in a fully reversible manner two-electron quinone oxidation/reduction with one-electron cytochrome c reduction/oxidation. Several features of this homodimeric enzyme implicate that in addition to its well-defined function of contributing to generation of proton-motive force, cytochrome bc1 may be a physiologically important point of regulation of electron flow acting as a sensor of the redox state of mitochondria that actively responds to changes in bioenergetic conditions. These features include the following: the opposing redox reactions at quinone catalytic sites located on the opposite sides of the membrane, the inter-monomer electronic connection that functionally links four quinone binding sites of a dimer into an H-shaped electron transfer system, as well as the potential to generate superoxide and release it to the intermembrane space where it can be engaged in redox signaling pathways. Here we highlight recent advances in understanding how cytochrome bc1 may accomplish this regulatory physiological function, what is known and remains unknown about catalytic and side reactions within the quinone binding sites and electron transfers through the cofactor chains connecting those sites with the substrate redox pools. We also discuss the developed molecular mechanisms in the context of physiology of mitochondria. PMID:25540143

  7. Transcriptional analysis of Volvox photoreceptors suggests the existence of different cell-type specific light-signaling pathways.

    PubMed

    Kianianmomeni, Arash; Hallmann, Armin

    2015-02-01

    Photosynthetic organisms, e.g., plants including green algae, use a sophisticated light-sensing system, composed of primary photoreceptors and additional downstream signaling components, to monitor changes in the ambient light environment towards adjust their growth and development. Although a variety of cellular processes, e.g., initiation of cleavage division and final cellular differentiation, have been shown to be light-regulated in the green alga Volvox carteri, little is known about the underlying light perception and signaling pathways. This multicellular alga possesses at least 12 photoreceptors, i.e., one phototropin (VcPhot), four cryptochromes (VcCRYa, VcCRYp, VcCRYd1, and VcCRYd2), and seven members of rhodopsin-like photoreceptors (VR1, VChR1, VChR2, VcHKR1, VcHKR2, VcHKR3, and VcHKR4), which display distinct light-dependent chemical processes based on their protein architectures and associated chromophores. Gene expression analyses could show that the transcript levels of some of the photoreceptor genes (e.g., VChR1 and VcHKR1) accumulate during division cleavages, while others (e.g., VcCRYa, VcCRYp, and VcPhot) accumulate during final cellular differentiation. However, the pattern of transcript accumulation changes when the alga switches to the sexual development. Eight photoreceptor genes, e.g., VcPhot, VcCRYp, and VcHKR1, are highly expressed in the somatic cells, while only the animal-type rhodopsin VR1 was found to be highly expressed in the reproductive cells/embryos during both asexual and sexual life cycles. Moreover, accumulation of VChR1 and VcCRYa transcripts is more sensitive to light and changes in response to more than one light quality. Obviously, different regulatory mechanisms underlying gene expression control transcript accumulation of photoreceptors not only during development, but also in a cell-type specific way and in response to various external signals such as light quality. The transcriptional patterns described in this study

  8. A study of specific features of the electronic spectrum of quantum dots in CdSe semiconductor

    NASA Astrophysics Data System (ADS)

    Mikhailov, A. I.; Kabanov, V. F.; Gorbachev, I. A.; Glukhovskoi, E. G.

    2016-08-01

    Monolayers of CdSe/CdS/ZnS quantum dots (QDs) formed on the aqueous subphase and transferred to solid substrates by the Langmuir-Blodgett method have been studied. The samples obtained were examined by transmission electron microscopy, atomic-force microscopy, and scanning tunnel microscopy. The structure of the QD monolayer obtained on the substrate was analyzed. Specific features of the electronic spectrum of the quantum objects formed in the samples under study were determined.

  9. LATS-YAP/TAZ controls lineage specification by regulating TGFβ signaling and Hnf4α expression during liver development

    PubMed Central

    Lee, Da-Hye; Park, Jae Oh; Kim, Tae-Shin; Kim, Sang-Kyum; Kim, Tack-hoon; Kim, Min-chul; Park, Gun Soo; Kim, Jeong-Hwan; Kuninaka, Shinji; Olson, Eric N.; Saya, Hideyuki; Kim, Seon-Young; Lee, Ho; Lim, Dae-Sik

    2016-01-01

    The Hippo pathway regulates the self-renewal and differentiation of various adult stem cells, but its role in cell fate determination and differentiation during liver development remains unclear. Here we report that the Hippo pathway controls liver cell lineage specification and proliferation separately from Notch signalling, using mice and primary hepatoblasts with liver-specific knockout of Lats1 and Lats2 kinase, the direct upstream regulators of YAP and TAZ. During and after liver development, the activation of YAP/TAZ induced by loss of Lats1/2 forces hepatoblasts or hepatocytes to commit to the biliary epithelial cell (BEC) lineage. It increases BEC and fibroblast proliferation by up-regulating TGFβ signalling, but suppresses hepatoblast to hepatocyte differentiation by repressing Hnf4α expression. Notably, oncogenic YAP/TAZ activation in hepatocytes induces massive p53-dependent cell senescence/death. Together, our results reveal that YAP/TAZ activity levels govern liver cell differentiation and proliferation in a context-dependent manner. PMID:27358050

  10. Nox2 contributes to the arterial endothelial specification of mouse induced pluripotent stem cells by upregulating Notch signaling

    PubMed Central

    Kang, Xueling; Wei, Xiangxiang; Wang, Xinhong; Jiang, Li; Niu, Cong; Zhang, Jianyi; Chen, Sifeng; Meng, Dan

    2016-01-01

    Reactive oxygen species (ROS) have a crucial role in stem-cell differentiation; however, the mechanisms by which ROS regulate the differentiation of stem cells into endothelial cells (ECs) are unknown. Here, we determine the role of ROS produced by NADPH oxidase 2 (Nox2) in the endothelial-lineage specification of mouse induced-pluripotent stem cells (miPSCs). When wild-type (WT) and Nox2-knockout (Nox2−/−) miPSCs were differentiated into ECs (miPSC-ECs), the expression of endothelial markers, arterial endothelial markers, pro-angiogenic cytokines, and Notch pathway components was suppressed in the Nox2−/− cells but increased in both WT and Nox2−/− miPSCs when Nox2 expression was upregulated. Higher levels of Nox2 expression increased Notch signaling and arterial EC differentiation, and this increase was abolished by the inhibition of ROS generation or by the silencing of Notch1 expression. Nox2 deficiency was associated with declines in the survival and angiogenic potency of miPSC-ECs, and capillary and arterial density were lower in the ischemic limbs of mice after treatment with Nox2−/− miPSC-ECs than WT miPSC-EC treatment. Taken together, these observations indicate that Nox2-mediated ROS production promotes arterial EC specification in differentiating miPSCs by activating the Notch signaling pathway and contributes to the angiogenic potency of transplanted miPSC-derived ECs. PMID:27642005

  11. Mechanism of transcription termination by RNA polymerase III utilizes a nontemplate-strand sequence-specific signal element

    PubMed Central

    Arimbasseri, Aneeshkumar G.; Maraia, Richard J.

    2015-01-01

    SUMMARY Understanding the mechanism of transcription termination by a eukaryotic RNA polymerase (RNAP) has been limited by lack of a characterizable intermediate that reflects transition from an elongation complex to a true termination event. While other multisubunit RNAPs require multipartite cis-signals and/or ancillary factors to mediate pausing and release of the nascent transcript from the clutches of these enzymes, RNAP III does so with precision and efficiency on a simple oligo(dT) tract, independent of other cis-elements or trans-factors. We report a RNAP III pre-termination complex that reveals termination mechanisms controlled by sequence-specific elements in the non-template strand. Furthermore, the TFIIF-like, RNAP III subunit, C37 is required for this function of the non-template strand signal. The results reveal the RNAP III terminator as an information-rich control element. While the template strand promotes destabilization via a weak oligo(rU:dA) hybrid, the non-template strand provides distinct sequence-specific destabilizing information through interactions with the C37 subunit. PMID:25959395

  12. A specific CD4 epitope bound by tregalizumab mediates activation of regulatory T cells by a unique signaling pathway.

    PubMed

    Helling, Bianca; König, Martin; Dälken, Benjamin; Engling, Andre; Krömer, Wolfgang; Heim, Katharina; Wallmeier, Holger; Haas, Jürgen; Wildemann, Brigitte; Fritz, Brigitte; Jonuleit, Helmut; Kubach, Jan; Dingermann, Theodor; Radeke, Heinfried H; Osterroth, Frank; Uherek, Christoph; Czeloth, Niklas; Schüttrumpf, Jörg

    2015-04-01

    CD4(+)CD25(+) regulatory T cells (Tregs) represent a specialized subpopulation of T cells, which are essential for maintaining peripheral tolerance and preventing autoimmunity. The immunomodulatory effects of Tregs depend on their activation status. Here we show that, in contrast to conventional anti-CD4 monoclonal antibodies (mAbs), the humanized CD4-specific monoclonal antibody tregalizumab (BT-061) is able to selectively activate the suppressive properties of Tregs in vitro. BT-061 activates Tregs by binding to CD4 and activation of signaling downstream pathways. The specific functionality of BT-061 may be explained by the recognition of a unique, conformational epitope on domain 2 of the CD4 molecule that is not recognized by other anti-CD4 mAbs. We found that, due to this special epitope binding, BT-061 induces a unique phosphorylation of T-cell receptor complex-associated signaling molecules. This is sufficient to activate the function of Tregs without activating effector T cells. Furthermore, BT-061 does not induce the release of pro-inflammatory cytokines. These results demonstrate that BT-061 stimulation via the CD4 receptor is able to induce T-cell receptor-independent activation of Tregs. Selective activation of Tregs via CD4 is a promising approach for the treatment of autoimmune diseases where insufficient Treg activity has been described. Clinical investigation of this new approach is currently ongoing. PMID:25512343

  13. Nox2 contributes to the arterial endothelial specification of mouse induced pluripotent stem cells by upregulating Notch signaling.

    PubMed

    Kang, Xueling; Wei, Xiangxiang; Wang, Xinhong; Jiang, Li; Niu, Cong; Zhang, Jianyi; Chen, Sifeng; Meng, Dan

    2016-01-01

    Reactive oxygen species (ROS) have a crucial role in stem-cell differentiation; however, the mechanisms by which ROS regulate the differentiation of stem cells into endothelial cells (ECs) are unknown. Here, we determine the role of ROS produced by NADPH oxidase 2 (Nox2) in the endothelial-lineage specification of mouse induced-pluripotent stem cells (miPSCs). When wild-type (WT) and Nox2-knockout (Nox2(-/-)) miPSCs were differentiated into ECs (miPSC-ECs), the expression of endothelial markers, arterial endothelial markers, pro-angiogenic cytokines, and Notch pathway components was suppressed in the Nox2(-/-) cells but increased in both WT and Nox2(-/-) miPSCs when Nox2 expression was upregulated. Higher levels of Nox2 expression increased Notch signaling and arterial EC differentiation, and this increase was abolished by the inhibition of ROS generation or by the silencing of Notch1 expression. Nox2 deficiency was associated with declines in the survival and angiogenic potency of miPSC-ECs, and capillary and arterial density were lower in the ischemic limbs of mice after treatment with Nox2(-/-) miPSC-ECs than WT miPSC-EC treatment. Taken together, these observations indicate that Nox2-mediated ROS production promotes arterial EC specification in differentiating miPSCs by activating the Notch signaling pathway and contributes to the angiogenic potency of transplanted miPSC-derived ECs. PMID:27642005

  14. Increasing the endogenous NO level causes catalase inactivation and reactivation of intercellular apoptosis signaling specifically in tumor cells.

    PubMed

    Bauer, Georg

    2015-12-01

    NO metabolism and direct catalase inhibitors. The latter aspect is explicitely studied for the interaction between catalase inhibiting acetylsalicylic acid and an NO donor. It is also shown that hybrid molecules like NO-aspirin utilize this synergistic potential. Our data open novel approaches for rational tumor therapy based on specific ROS signaling and its control in tumor cells.

  15. Increasing the endogenous NO level causes catalase inactivation and reactivation of intercellular apoptosis signaling specifically in tumor cells

    PubMed Central

    Bauer, Georg

    2015-01-01

    NO metabolism and direct catalase inhibitors. The latter aspect is explicitely studied for the interaction between catalase inhibiting acetylsalicylic acid and an NO donor. It is also shown that hybrid molecules like NO-aspirin utilize this synergistic potential. Our data open novel approaches for rational tumor therapy based on specific ROS signaling and its control in tumor cells. PMID:26342455

  16. Reprogramming CD19-specific T cells with IL-21 signaling can improve adoptive immunotherapy of B-lineage malignancies

    PubMed Central

    Singh, Harjeet; Figliola, Matthew J.; Dawson, Margaret J.; Huls, Helen; Olivares, Simon; Switzer, Kirsten; Mi, Tiejuan; Maiti, Sourindra; Kebriaei, Partow; Lee, Dean A.; Champlin, Richard E.; Cooper, Laurence J.N.

    2011-01-01

    Improving the therapeutic efficacy of T cells expressing a chimeric antigen receptor (CAR) represents an important goal in efforts to control B-cell malignancies. Recently an intrinsic strategy has been developed to modify the CAR itself to improve T-cell signaling. Here we report a second extrinsic approach based on altering the culture milieu to numerically expand CAR+ T cells with a desired phenotype. For, the addition of IL-21 to tissue culture improves CAR-dependent T-cell effector functions. We used electrotransfer of Sleeping Beauty (SB) system to introduce a CAR transposon and selectively propagate CAR+ T cells on CD19+ artificial antigen-presenting cells (aAPC). When IL-21 was present, there was preferential numeric expansion of CD19-specific T cells which lysed and produced IFN-γ in response to CD19. Populations of these numerically expanded CAR+ T cells displayed an early memory surface phenotype characterized as CD62L+CD28+ and a transcriptional profile of naïve T cells. In contrast, T cells propagated with only exogenous IL-2 tended to result in an overgrowth of CD19-specific CD4+ T cells. Furthermore, adoptive transfer of CAR+ T cells cultured with IL-21 exhibited improved control of CD19+ B-cell malignancy in mice. To provide coordinated signaling to propagate CAR+ T cells, we developed a novel mutein of IL-21 bound to the cell surface of aAPC that replaced the need for soluble IL-21. Our findings demonstrate that IL-21 can provide an extrinsic reprogramming signal to generate desired CAR+ T cells for effective immunotherapy. PMID:21558388

  17. Reprogramming CD19-specific T cells with IL-21 signaling can improve adoptive immunotherapy of B-lineage malignancies.

    PubMed

    Singh, Harjeet; Figliola, Matthew J; Dawson, Margaret J; Huls, Helen; Olivares, Simon; Switzer, Kirsten; Mi, Tiejuan; Maiti, Sourindra; Kebriaei, Partow; Lee, Dean A; Champlin, Richard E; Cooper, Laurence J N

    2011-05-15

    Improving the therapeutic efficacy of T cells expressing a chimeric antigen receptor (CAR) represents an important goal in efforts to control B-cell malignancies. Recently an intrinsic strategy has been developed to modify the CAR itself to improve T-cell signaling. Here we report a second extrinsic approach based on altering the culture milieu to numerically expand CAR(+) T cells with a desired phenotype, for the addition of interleukin (IL)-21 to tissue culture improves CAR-dependent T-cell effector functions. We used electrotransfer of Sleeping Beauty system to introduce a CAR transposon and selectively propagate CAR(+) T cells on CD19(+) artificial antigen-presenting cells (aAPC). When IL-21 was present, there was preferential numeric expansion of CD19-specific T cells which lysed and produced IFN-γ in response to CD19. Populations of these numerically expanded CAR(+) T cells displayed an early memory surface phenotype characterized as CD62L(+)CD28(+) and a transcriptional profile of naïve T cells. In contrast, T cells propagated with only exogenous IL-2 tended to result in an overgrowth of CD19-specific CD4(+) T cells. Furthermore, adoptive transfer of CAR(+) T cells cultured with IL-21 exhibited improved control of CD19(+) B-cell malignancy in mice. To provide coordinated signaling to propagate CAR(+) T cells, we developed a novel mutein of IL-21 bound to the cell surface of aAPC that replaced the need for soluble IL-21. Our findings show that IL-21 can provide an extrinsic reprogramming signal to generate desired CAR(+) T cells for effective immunotherapy. PMID:21558388

  18. An electronic Doppler signal generator for assessing continuous-wave ultrasonic Doppler flowmeters

    NASA Astrophysics Data System (ADS)

    Smallwood, R. H.; Dixon, P.

    1986-03-01

    The design and performance of the electric Doppler signal generator are described. The features of the CW ultrasonic Doppler flowmeter, which operates in the 2-10 MHz range, that are relevant to the design of the generator are examined. Methods for evaluating the bandwidth, dynamic range, directional separation, and linearity of the zero-crossing detector are discussed. The use of a polyphase network as a phase shifter to generate a single sideband (SSB) signal is analyzed. The SSB generation is performed at a frequency of 100 kHz and the advantages of generation at this frequency are stated. The selection of proper SSB signals for the system is investigated. The performance of the Doppler signal generator is evaluated with a frequency analyzer; sideband rejection ratios and phase error in the quadrature oscillator are calculated. The Doppler generator was applied to a CW flowmeter and output signal levels were measured. The test reveals that the Doppler signal generator's performance exceeds the flowmeter requirements; rejection of the unwanted sideband exceeds 40 dB for Doppler frequencies up to 10 kHz, which is the minimum upper frequency for 10 MHz flowmeters.

  19. Effect of chlorine activation treatment on electron beam induced current signal distribution of cadmium telluride thin film solar cells

    NASA Astrophysics Data System (ADS)

    Zywitzki, Olaf; Modes, Thomas; Morgner, Henry; Metzner, Christoph; Siepchen, Bastian; Späth, Bettina; Drost, Christian; Krishnakumar, Velappan; Frauenstein, Sven

    2013-10-01

    We have investigated CdTe thin film solar cells without activation treatment and with CdCl2 activation treatment at temperatures between 370 and 430 °C using a constant activation time of 25 min. For this purpose, CdS/CdTe layers were deposited by closed-space-sublimation on FTO coated float glass. The solar cells were characterized by measurements of the JV characteristics and quantum efficiencies. In addition, ion polished cross sections of the solar cells were prepared for high-resolution FE-SEM imaging of the microstructure and the simultaneous registration of electron beam induced current (EBIC) signal distribution. By measurement of the EBIC signal distribution, it can be shown that without activation treatment the CdTe grain boundaries itself and grain boundary near regions exhibit no EBIC signal, whereas centres of some singular grains already show a distinct EBIC signal. In contrast, after the chlorine activation treatment, the grain boundary near regions exhibit a significant higher EBIC signal than the centre of the grains. The results can be discussed as a direct evidence for defect passivation of grain boundary near regions by the chlorine activation treatment. At activation temperature of 430 °C, additionally, a significant grain growth and agglomeration of the CdS layer can be recognized, which is linked with the formation of voids within the CdS layer and a deterioration of pn junction properties.

  20. Production of Solar Cells in Space from Non Specific Ores by Utilization of Electronically Enhanced Sputtering

    NASA Technical Reports Server (NTRS)

    Curreri, Peter A.

    2009-01-01

    An ideal method of construction in space would utilize some form of the Universal Differentiator and Universal Constructor as described by Von Neumann (1). The Universal Differentiator is an idealized non ore specific extractive device which is capable of breaking any ore into its constituent elements, and the Universal Constructor can utilize these elements to build any device with controllability to the nanometer scale. During the Human Exploration Initiative program in the early 1990s a conceptual study was done (2) to understand whether such devices were feasible with near term technology for the utilization of space resources and energy. A candidate system was proposed which would utilize electronically enhanced sputtering as the differentiator. Highly ionized ions would be accelerated to a kinetic energy at which the interaction between them and the lattice elections in the ore would be at a maximum. Experiments have shown that the maximum disintegration of raw material occurs at an ion kinetic energy of about 5 MeV, regardless of the composition and structure of the raw material. Devices that could produce charged ion beams in this energy range in space were being tested in the early 1990s. At this energy, for example an ion in a beam of fluorine ions yields about 8 uranium ions from uranium fluoride, 1,400 hydrogen and oxygen atoms from ice, or 7,000 atoms from sulfur dioxide ice. The ions from the disintegrated ore would then be driven by an electrical field into a discriminator in the form of a mass spectrometer, where the magnetic field would divert the ions into collectors for future use or used directly in molecular beam construction techniques. The process would require 10-7 Torr vacuum which would be available in space or on the moon. If the process were used to make thin film silicon solar cells (ignoring any energy inefficiency for beam production), then energy break even for solar cells in space would occur after 14 days.

  1. Rescue of PINK1 Protein Null-specific Mitochondrial Complex IV Deficits by Ginsenoside Re Activation of Nitric Oxide Signaling*

    PubMed Central

    Kim, Kyung-Hee; Song, Karen; Yoon, Seung-Hee; Shehzad, Omer; Kim, Yeong-Shik; Son, Jin H.

    2012-01-01

    PINK1, linked to familial Parkinson's disease, is known to affect mitochondrial function. Here we identified a novel regulatory role of PINK1 in the maintenance of complex IV activity and characterized a novel mechanism by which NO signaling restored complex IV deficiency in PINK1 null dopaminergic neuronal cells. In PINK1 null cells, levels of specific chaperones, including Hsp60, leucine-rich pentatricopeptide repeat-containing (LRPPRC), and Hsp90, were severely decreased. LRPPRC and Hsp90 were found to act upstream of Hsp60 to regulate complex IV activity. Specifically, knockdown of Hsp60 resulted in a decrease in complex IV activity, whereas antagonistic inhibition of Hsp90 by 17-(allylamino) geldanamycin decreased both Hsp60 and complex IV activity. In contrast, overexpression of the PINK1-interacting factor LRPPRC augmented complex IV activity by up-regulating Hsp60. A similar recovery of complex IV activity was also induced by coexpression of Hsp90 and Hsp60. Drug screening identified ginsenoside Re as a compound capable of reversing the deficit in complex IV activity in PINK1 null cells through specific increases of LRPPRC, Hsp90, and Hsp60 levels. The pharmacological effects of ginsenoside Re could be reversed by treatment of the pan-NOS inhibitor l-NG-Nitroarginine Methyl Ester (l-NAME) and could also be reproduced by low-level NO treatment. These results suggest that PINK1 regulates complex IV activity via interactions with upstream regulators of Hsp60, such as LRPPRC and Hsp90. Furthermore, they demonstrate that treatment with ginsenoside Re enhances functioning of the defective PINK1-Hsp90/LRPPRC-Hsp60-complex IV signaling axis in PINK1 null neurons by restoring NO levels, providing potential for new therapeutics targeting mitochondrial dysfunction in Parkinson's disease. PMID:23144451

  2. Rescue of PINK1 protein null-specific mitochondrial complex IV deficits by ginsenoside Re activation of nitric oxide signaling.

    PubMed

    Kim, Kyung-Hee; Song, Karen; Yoon, Seung-Hee; Shehzad, Omer; Kim, Yeong-Shik; Son, Jin H

    2012-12-28

    PINK1, linked to familial Parkinson's disease, is known to affect mitochondrial function. Here we identified a novel regulatory role of PINK1 in the maintenance of complex IV activity and characterized a novel mechanism by which NO signaling restored complex IV deficiency in PINK1 null dopaminergic neuronal cells. In PINK1 null cells, levels of specific chaperones, including Hsp60, leucine-rich pentatricopeptide repeat-containing (LRPPRC), and Hsp90, were severely decreased. LRPPRC and Hsp90 were found to act upstream of Hsp60 to regulate complex IV activity. Specifically, knockdown of Hsp60 resulted in a decrease in complex IV activity, whereas antagonistic inhibition of Hsp90 by 17-(allylamino) geldanamycin decreased both Hsp60 and complex IV activity. In contrast, overexpression of the PINK1-interacting factor LRPPRC augmented complex IV activity by up-regulating Hsp60. A similar recovery of complex IV activity was also induced by coexpression of Hsp90 and Hsp60. Drug screening identified ginsenoside Re as a compound capable of reversing the deficit in complex IV activity in PINK1 null cells through specific increases of LRPPRC, Hsp90, and Hsp60 levels. The pharmacological effects of ginsenoside Re could be reversed by treatment of the pan-NOS inhibitor L-NG-Nitroarginine Methyl Ester (L-NAME) and could also be reproduced by low-level NO treatment. These results suggest that PINK1 regulates complex IV activity via interactions with upstream regulators of Hsp60, such as LRPPRC and Hsp90. Furthermore, they demonstrate that treatment with ginsenoside Re enhances functioning of the defective PINK1-Hsp90/LRPPRC-Hsp60-complex IV signaling axis in PINK1 null neurons by restoring NO levels, providing potential for new therapeutics targeting mitochondrial dysfunction in Parkinson's disease. PMID:23144451

  3. A brain-computer interface for potential non-verbal facial communication based on EEG signals related to specific emotions.

    PubMed

    Kashihara, Koji

    2014-01-01

    Unlike assistive technology for verbal communication, the brain-machine or brain-computer interface (BMI/BCI) has not been established as a non-verbal communication tool for amyotrophic lateral sclerosis (ALS) patients. Face-to-face communication enables access to rich emotional information, but individuals suffering from neurological disorders, such as ALS and autism, may not express their emotions or communicate their negative feelings. Although emotions may be inferred by looking at facial expressions, emotional prediction for neutral faces necessitates advanced judgment. The process that underlies brain neuronal responses to neutral faces and causes emotional changes remains unknown. To address this problem, therefore, this study attempted to decode conditioned emotional reactions to neutral face stimuli. This direction was motivated by the assumption that if electroencephalogram (EEG) signals can be used to detect patients' emotional responses to specific inexpressive faces, the results could be incorporated into the design and development of BMI/BCI-based non-verbal communication tools. To these ends, this study investigated how a neutral face associated with a negative emotion modulates rapid central responses in face processing and then identified cortical activities. The conditioned neutral face-triggered event-related potentials that originated from the posterior temporal lobe statistically significantly changed during late face processing (600-700 ms) after stimulus, rather than in early face processing activities, such as P1 and N170 responses. Source localization revealed that the conditioned neutral faces increased activity in the right fusiform gyrus (FG). This study also developed an efficient method for detecting implicit negative emotional responses to specific faces by using EEG signals. A classification method based on a support vector machine enables the easy classification of neutral faces that trigger specific individual emotions. In

  4. A brain-computer interface for potential non-verbal facial communication based on EEG signals related to specific emotions.

    PubMed

    Kashihara, Koji

    2014-01-01

    Unlike assistive technology for verbal communication, the brain-machine or brain-computer interface (BMI/BCI) has not been established as a non-verbal communication tool for amyotrophic lateral sclerosis (ALS) patients. Face-to-face communication enables access to rich emotional information, but individuals suffering from neurological disorders, such as ALS and autism, may not express their emotions or communicate their negative feelings. Although emotions may be inferred by looking at facial expressions, emotional prediction for neutral faces necessitates advanced judgment. The process that underlies brain neuronal responses to neutral faces and causes emotional changes remains unknown. To address this problem, therefore, this study attempted to decode conditioned emotional reactions to neutral face stimuli. This direction was motivated by the assumption that if electroencephalogram (EEG) signals can be used to detect patients' emotional responses to specific inexpressive faces, the results could be incorporated into the design and development of BMI/BCI-based non-verbal communication tools. To these ends, this study investigated how a neutral face associated with a negative emotion modulates rapid central responses in face processing and then identified cortical activities. The conditioned neutral face-triggered event-related potentials that originated from the posterior temporal lobe statistically significantly changed during late face processing (600-700 ms) after stimulus, rather than in early face processing activities, such as P1 and N170 responses. Source localization revealed that the conditioned neutral faces increased activity in the right fusiform gyrus (FG). This study also developed an efficient method for detecting implicit negative emotional responses to specific faces by using EEG signals. A classification method based on a support vector machine enables the easy classification of neutral faces that trigger specific individual emotions. In

  5. A brain-computer interface for potential non-verbal facial communication based on EEG signals related to specific emotions

    PubMed Central

    Kashihara, Koji

    2014-01-01

    Unlike assistive technology for verbal communication, the brain-machine or brain-computer interface (BMI/BCI) has not been established as a non-verbal communication tool for amyotrophic lateral sclerosis (ALS) patients. Face-to-face communication enables access to rich emotional information, but individuals suffering from neurological disorders, such as ALS and autism, may not express their emotions or communicate their negative feelings. Although emotions may be inferred by looking at facial expressions, emotional prediction for neutral faces necessitates advanced judgment. The process that underlies brain neuronal responses to neutral faces and causes emotional changes remains unknown. To address this problem, therefore, this study attempted to decode conditioned emotional reactions to neutral face stimuli. This direction was motivated by the assumption that if electroencephalogram (EEG) signals can be used to detect patients' emotional responses to specific inexpressive faces, the results could be incorporated into the design and development of BMI/BCI-based non-verbal communication tools. To these ends, this study investigated how a neutral face associated with a negative emotion modulates rapid central responses in face processing and then identified cortical activities. The conditioned neutral face-triggered event-related potentials that originated from the posterior temporal lobe statistically significantly changed during late face processing (600–700 ms) after stimulus, rather than in early face processing activities, such as P1 and N170 responses. Source localization revealed that the conditioned neutral faces increased activity in the right fusiform gyrus (FG). This study also developed an efficient method for detecting implicit negative emotional responses to specific faces by using EEG signals. A classification method based on a support vector machine enables the easy classification of neutral faces that trigger specific individual emotions. In

  6. Electron

    NASA Astrophysics Data System (ADS)

    Springford, Michael

    1997-03-01

    1. J. J. Thomson and the discovery of the electron A. B. P. Pippard; 2. The isolated electron W. N. Cottingham; 3. The relativistic electron D. I. Olive; 4. The electron glue B. L. Gyorffy; 5. The electron fluid P. Coleman; 6. The magnetic electron G. G. Lonzarich; 7. The paired electron A. J. Leggett; 8. The heavy electron M. Springford; 9. The coherent electron Y. Imry and M. Peskin; 10. The composite electron R. Nicholas; 11. The electron in the cosmos M. S. Longair.

  7. Electron

    NASA Astrophysics Data System (ADS)

    Springford, Michael

    2008-12-01

    1. J. J. Thomson and the discovery of the electron A. B. P. Pippard; 2. The isolated electron W. N. Cottingham; 3. The relativistic electron D. I. Olive; 4. The electron glue B. L. Gyorffy; 5. The electron fluid P. Coleman; 6. The magnetic electron G. G. Lonzarich; 7. The paired electron A. J. Leggett; 8. The heavy electron M. Springford; 9. The coherent electron Y. Imry and M. Peskin; 10. The composite electron R. Nicholas; 11. The electron in the cosmos M. S. Longair.

  8. Erect Wing facilitates context-dependent Wnt/Wingless signaling by recruiting the cell-specific Armadillo-TCF adaptor Earthbound to chromatin

    PubMed Central

    Xin, Nan; Benchabane, Hassina; Tian, Ai; Nguyen, Kerrie; Klofas, Lindsay; Ahmed, Yashi

    2011-01-01

    During metazoan development, the Wnt/Wingless signal transduction pathway is activated repetitively to direct cell proliferation, fate specification, differentiation and apoptosis. Distinct outcomes are elicited by Wnt stimulation in different cellular contexts; however, mechanisms that confer context specificity to Wnt signaling responses remain largely unknown. Starting with an unbiased forward genetic screen in Drosophila, we recently uncovered a novel mechanism by which the cell-specific co-factor Earthbound 1 (Ebd1), and its human homolog jerky, promote interaction between the Wnt pathway transcriptional co-activators β-catenin/Armadillo and TCF to facilitate context-dependent Wnt signaling responses. Here, through the same genetic screen, we find an unanticipated requirement for Erect Wing (Ewg), the fly homolog of the human sequence-specific DNA-binding transcriptional activator nuclear respiratory factor 1 (NRF1), in promoting contextual regulation of Wingless signaling. Ewg and Ebd1 functionally interact with the Armadillo-TCF complex and mediate the same context-dependent Wingless signaling responses. In addition, Ewg and Ebd1 have similar cell-specific expression profiles, bind to each other directly and also associate with chromatin at shared genomic sites. Furthermore, recruitment of Ebd1 to chromatin is abolished in the absence of Ewg. Our findings provide in vivo evidence that recruitment of a cell-specific co-factor complex to specific chromatin sites, coupled with its ability to facilitate Armadillo-TCF interaction and transcriptional activity, promotes contextual regulation of Wnt/Wingless signaling responses. PMID:22028028

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

    PubMed Central

    Duran-Flores, Dalia; Heil, Martin

    2014-01-01

    Plants require reliable mechanisms to detect injury. Danger signals or “damage-associated molecular patterns” (DAMPs) are released from stressed host cells and allow injury detection independently of enemy-derived molecules. We studied the response of common bean (Phaseolus vulgaris) to the application of leaf homogenate as a source of DAMPs and measured the production of reactive oxygen species (ROS) as an early response and the secretion of extrafloral nectar (EFN) as a jasmonic acid (JA)-dependent late response. We observed a strong taxonomic signal in the response to different leaf homogenates. ROS formation and EFN secretion were highly correlated and responded most strongly to leaf homogenates produced using the same cultivar or closely related accessions, less to a distantly related cultivar of common bean or each of the two congeneric species, P. lunatus and P. coccineus, and not at all to homogenates prepared from species in different genera, not even when using other Fabaceae. Interestingly, leaf homogenates also reduced the infection by the bacterial pathogen, Pseudomonas syringae, when they were applied directly before challenging, although the same homogenates exhibited no direct in vitro inhibitory effect in the bacterium. We conclude that ROS signaling is associated to the induction of EFN secretion and that the specific blend of DAMPs that are released from damaged cells allows the plant to distinguish the “damaged-self” from the damaged “non-self.” The very early responses of plants to DAMPs can trigger resistance to both, herbivores and pathogens, which should be adaptive because injury facilitates infection, independently of its causal reason. PMID:25400650

  10. Specific energy from Auger and conversion electrons of 131I, 188Re-anti-CD20 to a lymphocyte's nucleus

    NASA Astrophysics Data System (ADS)

    Torres-García, E.; Carrillo-Cazares, T. A.

    2011-01-01

    The typical radionuclides used to label anti-CD20 in the treatment of non-Hodgkin's lymphoma are 90Y, 131I, and 188Re, with the emission of beta particles, Auger electrons, and conversion electrons for the latter two. The aim of the present work was to calculate the contribution of high linear energy transfer radiation as Auger electrons (AE) and conversion electrons (CE) of 131I and 188Re-anti-CD20 to mean specific energy into the cell nucleus by Monte Carlo simulation (MCS), so as to infer therapeutic effectiveness on a dosimetric basis. MCS was used to quantify the frequency-mean specific energy into the cell nucleus, where the cell was modeled by two concentric spheres, considering two cell models. The results showed that 10% and 33% of the mean-specific energies (z¯) per disintegration imparted to the cell nucleus for both geometries are due to AE and CE; on the other hand, if the hit of AE and CE occurs, the contribution to (z¯) is about 64% and 86% for 131I and 188Re, respectively. According to the amount of specific energy from AE and CE into the cell nucleus by positive event, they can cause catastrophic effects in the nuclear DNA in the treatment of non-Hodgkin's lymphoma with 131I, 188Re-anti-CD20.

  11. Cell-type specific photoreceptors and light signaling pathways in the multicellular green alga Volvox carteri and their potential role in cellular differentiation.

    PubMed

    Kianianmomeni, Arash

    2015-01-01

    The formation of multicellular organisms requires genetically predefined signaling pathways in various cell types. Besides differences in size, energy balance and life time, cell types should be enable to modulate appropriate developmental and adaptive responses in ever-changing surrounding environment. One of the most important environmental cues is light which regulates a variety of physiological and cellular processes. During evolution, diverse light-sensitive proteins, so-called photoreceptors, and corresponding signaling pathways have evolved, in almost all kingdoms of life, to monitor light continuously and adjust their growth and development accordingly. However, considering the fact that different cell types should be enable to trigger distinct light signaling pathways according to their needs, cell-type specific light signaling pathways are required to guarantee cell type-matched modulation of cellular and developmental processes in response to different light signals. The multicellular green alga Volvox carteri, which has only 2 cell types with clear division of labor, possesses cell-type specific photoreceptors and light signaling pathways which allow differential regulation of genes involved in various cellular and metabolic pathways in response to environmental light. The existence of cell-type specific light signaling pathways in multicellular organism like Volvox reflects an early development of cell-type specific signaling mechanisms during evolution to ensure maintenance of differentiation. PMID:25874475

  12. Theory of signal and noise in double-gated nanoscale electronic pH sensors

    SciTech Connect

    Go, Jonghyun; Nair, Pradeep R.; Alam, Muhammad A.

    2012-08-01

    The maximum sensitivity of classical nanowire (NW)-based pH sensors is defined by the Nernst limit of 59 mV/pH. For typical noise levels in ultra-small single-gated nanowire sensors, the signal-to-noise ratio is often not sufficient to resolve pH changes necessary for a broad range of applications. Recently, a new class of double-gated devices was demonstrated to offer apparent 'super-Nernstian' response (>59 mV/pH) by amplifying the original pH signal through innovative biasing schemes. However, the pH-sensitivity of these nanoscale devices as a function of biasing configurations, number of electrodes, and signal-to-noise ratio (SNR) remains poorly understood. Even the basic question such as 'Do double-gated sensors actually resolve smaller changes in pH compared to conventional single-gated sensors in the presence of various sources of noise?' remains unanswered. In this article, we provide a comprehensive numerical and analytical theory of signal and noise of double-gated pH sensors to conclude that, while the theoretical lower limit of pH-resolution does not improve for double-gated sensors, this new class of sensors does improve the (instrument-limited) pH resolution.

  13. [The reflection of the motivational status in the spectral characteristics of the species-specific acoustic signals of the domestic cat].

    PubMed

    Sokolova, N N; Liakso, E E

    1989-01-01

    Spectral characteristics of species-specific acoustic signals were analyzed in cats under various unfavourable conditions: hunger, isolation, pain stimulation, agony. The increase in the need to get rid of the discomfort accompanied by the development of emotional excitation was reflected in spectral characteristics of produced signals. The frequency and duration of signals increased, their spectrum widened accompanied by spectral maxima shifted towards the high-frequency area similar to the range of formant frequencies in the signals of newborn kittens. The similarity between spectral characteristics of the above signals in adult and newborn cats might indicate the appearance of infantile features in adult cats under conditions of a marked desire to change the existing situation. The fact that motivational state was reflected in spectral characteristics of acoustic signals along with stable responses to the signals, spoke in favour of a considerable contribution made by communication to the organization of intraspecific relations.

  14. Signal amplification strategy for sensitive immunoassay of prostate specific antigen (PSA) based on ferrocene incorporated polystyrene spheres.

    PubMed

    Ding, Lu; You, Jinmao; Kong, Rongmei; Qu, Fengli

    2013-09-01

    A new kind of signal amplification strategy based on ferrocene (Fc) incorporated polystyrene spheres (PS-Fc) was proposed. The synthesized PS-Fc displayed narrow size distribution and good stability. PS-Fc was applied as label to develop immunosensors for prostate specific antigen (PSA) after the typical sandwich immunoreaction by linking anti-PSA antibody (Ab2) onto PS-Fc. After the fabrication of the immunosensor, tetrahydrofuran (THF) was dropped to dissolve PS and release the contained Fc for the following stripping voltammetric detection. PS-Fc as a new electrochemical label prevented the leakage of Fc and greatly amplified the immunosensor signal. In addition, the good biocompatibility of PS could maintain the bioactivity of the antibodies. The response current was linear to the logarithm of PSA concentration in the range from 0.01 ng mL(-1) to 20 ng mL(-1) with a detection limit of 1 pg mL(-1). The immunosensor results were validated through the detection of PSA in serum samples with satisfactory results.

  15. Myofiber-specific inhibition of TGFβ signaling protects skeletal muscle from injury and dystrophic disease in mice

    PubMed Central

    Accornero, Federica; Kanisicak, Onur; Tjondrokoesoemo, Andoria; Attia, Aria C.; McNally, Elizabeth M.; Molkentin, Jeffery D.

    2014-01-01

    Muscular dystrophy (MD) is a disease characterized by skeletal muscle necrosis and the progressive accumulation of fibrotic tissue. While transforming growth factor (TGF)-β has emerged as central effector of MD and fibrotic disease, the cell types in diseased muscle that underlie TGFβ-dependent pathology have not been segregated. Here, we generated transgenic mice with myofiber-specific inhibition of TGFβ signaling owing to expression of a TGFβ type II receptor dominant-negative (dnTGFβRII) truncation mutant. Expression of dnTGFβRII in myofibers mitigated the dystrophic phenotype observed in δ-sarcoglycan-null (Sgcd−/−) mice through a mechanism involving reduced myofiber membrane fragility. The dnTGFβRII transgene also reduced muscle injury and improved muscle regeneration after cardiotoxin injury, as well as increased satellite cell numbers and activity. An unbiased global expression analysis revealed a number of potential mechanisms for dnTGFβRII-mediated protection, one of which was induction of the antioxidant protein metallothionein (Mt). Indeed, TGFβ directly inhibited Mt gene expression in vitro, the dnTGFβRII transgene conferred protection against reactive oxygen species accumulation in dystrophic muscle and treatment with Mt mimetics protected skeletal muscle upon injury in vivo and improved the membrane stability of dystrophic myofibers. Hence, our results show that the myofibers are central mediators of the deleterious effects associated with TGFβ signaling in MD. PMID:25106553

  16. Multisensory signals trigger approach behaviour in the fire-bellied toad Bombina orientalis: sex differences and call specificity.

    PubMed

    Zeyl, Jeffrey N; Laberge, Frédéric

    2011-12-01

    Animal communication often involves multimodal signals, and interactions between sensory modalities can trigger unique responses in receivers. Response to social signals was investigated in fire-bellied toads by exposing them to playback of male calls (advertisement and release calls) and a video clip of a male conspecific in the laboratory. The cues were presented in isolation and as a combined bimodal stimulus, and approach frequency, latency to approach and time spent around the stimulus source were measured. No positive phonotaxis was observed toward the advertisement call, both during the day and during a phonotaxis trial performed at night. However, females, but not males, approached with greater frequency, lower latency, and spent more time near the source of the bimodal stimulus in an experiment involving the advertisement call. Female response was specific to the advertisement call, as approach was not increased when the release call was used. Males, on the other hand, did not show increased approach in the advertisement call experiment, but approached with greater frequency the bimodal stimulus involving the release call within the first minute of stimulus presentation. The findings suggest that females orient toward calling males and that males eavesdrop on release calls, but in both cases a visual stimulus is also needed to trigger a response. Social approach in Bombina orientalis is thus dependent on multisensory cues, and the nature of the interaction between sensory modalities depends on receiver sex and call type. PMID:21993061

  17. Multisensory signals trigger approach behaviour in the fire-bellied toad Bombina orientalis: sex differences and call specificity.

    PubMed

    Zeyl, Jeffrey N; Laberge, Frédéric

    2011-12-01

    Animal communication often involves multimodal signals, and interactions between sensory modalities can trigger unique responses in receivers. Response to social signals was investigated in fire-bellied toads by exposing them to playback of male calls (advertisement and release calls) and a video clip of a male conspecific in the laboratory. The cues were presented in isolation and as a combined bimodal stimulus, and approach frequency, latency to approach and time spent around the stimulus source were measured. No positive phonotaxis was observed toward the advertisement call, both during the day and during a phonotaxis trial performed at night. However, females, but not males, approached with greater frequency, lower latency, and spent more time near the source of the bimodal stimulus in an experiment involving the advertisement call. Female response was specific to the advertisement call, as approach was not increased when the release call was used. Males, on the other hand, did not show increased approach in the advertisement call experiment, but approached with greater frequency the bimodal stimulus involving the release call within the first minute of stimulus presentation. The findings suggest that females orient toward calling males and that males eavesdrop on release calls, but in both cases a visual stimulus is also needed to trigger a response. Social approach in Bombina orientalis is thus dependent on multisensory cues, and the nature of the interaction between sensory modalities depends on receiver sex and call type.

  18. Insights into the species-specific TLR4 signaling mechanism in response to Rhodobacter sphaeroides lipid A detection

    NASA Astrophysics Data System (ADS)

    Anwar, Muhammad Ayaz; Panneerselvam, Suresh; Shah, Masaud; Choi, Sangdun

    2015-01-01

    TLR4 in complex with MD2 senses the presence of lipid A (LA) and initiates a signaling cascade that curb the infection. This complex is evolutionarily conserved and can initiate the immune system in response to a variety of LAs. In this study, molecular dynamics simulation (25 ns) was performed to elucidate the differential behavior of TLR4/MD2 complex in response to Rhodobacter sphaeroides lipid A (RsLA). Penta-acyl chain-containing RsLA is at the verge of agonist (6 acyl-chains) and antagonist (4 acyl-chains) structure, and activates the TLR4 pathway in horses and hamsters, while inhibiting in humans and murine. In the time-evolved coordinates, the promising factors that dictated the differential response included the local and global mobility pattern of complexes, solvent-accessible surface area of ligand, and surface charge distributions of TLR4 and MD2. We showed that the GlcN1-GlcN2 backbone acquires agonist (3FXI)-like configurations in horses and hamsters, while acquiring antagonist (2E59)-like configurations in humans and murine systems. Moreover, analysis of F126 behavior in the MD2 F126 loop (amino acids 123-129) and loop EF (81-89) suggested that certain sequence variations also contribute to species-specific response. This study underlines the TLR4 signaling mechanism and provides new therapeutic opportunities.

  19. Phosphatidylinositol 3-kinase signals activation of p70 S6 kinase in situ through site-specific p70 phosphorylation.

    PubMed Central

    Weng, Q P; Andrabi, K; Klippel, A; Kozlowski, M T; Williams, L T; Avruch, J

    1995-01-01

    The p70 S6 kinase is activated by insulin and mitogens through multisite phosphorylation of the enzyme. One set of activating phosphorylations occurs in a putative autoinhibitory domain in the noncatalytic carboxyl-terminal tail. Deletion of this tail yields a variant (p70 delta CT104) that nevertheless continues to be mitogen regulated. Coexpression with a recombinant constitutively active phosphatidylinositol (PI) 3-kinase (EC 2.7.1.137) gives substantial activation of both full-length p70 and p70 delta CT104 but not Rsk. Activation of p70 delta CT104 by PI 3-kinase and inhibition by wortmannin are each accompanied by parallel and selective changes in the phosphorylation of p70 Thr-252. A Thr or Ser at this site, in subdomain VIII of the catalytic domain just amino-terminal to the APE motif, is necessary for p70 40S kinase activity. The inactive ATP-binding site mutant K123M p70 delta CT104 undergoes phosphorylation of Thr-252 in situ but does not undergo direct phosphorylation by the active PI 3-kinase in vitro. PI 3-kinase provides a signal necessary for the mitogen activation of the p70 S6 kinase, which directs the site-specific phosphorylation of Thr-252 in the p70 catalytic domain, through a distinctive signal transduction pathway. Images Fig. 1 Fig. 2 Fig. 3 PMID:7777579

  20. [Genetic aspects of sexual behavior in malaria mosquitoes on the basis of specific acoustic signals at mating].

    PubMed

    Perevozkin, V P; Printseva, A A; Maslennikov, P V; Bondarchuk, S S

    2012-06-01

    Acoustic characteristics were studied in two species of the "Anopheles maculipennis" species complex, A. messeae and A. atroparvus. The species were found to clearly differ in sound frequencies, which was assumed to play a key role in species identification during mating in regions of their sympatric distribution. The sound spectrum in A. messeae was far more diverse than in A. atroparvus, which was associated with intraspecific inversion polymorphism of the former. Mosquitoes with the inversion combinations that were most common in populations of the central region of the A. messeae species area specifically differed in acoustic signal spectrum from each other. Hence, sound communication within the species was considered to be the main mechanism that is responsible for sexual partner selection and determines the chromosome associations observed earlier in individual karyotypes. Since males carrying different inversion combinations significantly differed in acoustic characteristics, females were assumed to play a main role in selecting the sexual partner.

  1. Small signal theory of an E×B drifting electron laser

    NASA Astrophysics Data System (ADS)

    Riyopoulos, Spilios

    1997-02-01

    The concept of the drifting electron laser (DEL), powered by a relativistic beam of E×B drifting electrons in crossed electric and magnetic fields, is introduced. The wiggling motion is generated by adding a periodic modulation in either E or B. In contrast to free electron lasers (FELs) converting kinetic energy and momentum into radiation, the emitted radiation energy and momentum in a DEL come respectively from the change in the electrostatic energy eE0 δX and vector potential eB0 δX of the electron, δX being the quantum recoil of the guiding center (GC) location perpendicular to the drift direction. The difference between stimulated emission and absorption responsible for the gain is provided by the transverse gradient of the wiggler strength, and the gain curve is symmetric relative to the frequency detuning δω. Since the drift velocity and the resonance condition are energy independent, one avoids the low efficiency limits placed on FELs from energy detuning and thermal spreads. Beam energy spreads turn into spreads in the GC location, reducing the gain sensitivity to the beam quality. Saturation in a DEL occurs via the off-axis walk of the emitting electrons. Overlap between the beam and the radiation is maintained by a small tilt of the resonator axis relative to the E×B drift direction.

  2. Factors Influencing Continuous Breath Signal in Intubated and Mechanically-Ventilated Intensive Care Unit Patients Measured by an Electronic Nose

    PubMed Central

    Leopold, Jan Hendrik; Abu-Hanna, Ameen; Colombo, Camilla; Sterk, Peter J.; Schultz, Marcus J.; Bos, Lieuwe D. J.

    2016-01-01

    Introduction: Continuous breath analysis by electronic nose (eNose) technology in the intensive care unit (ICU) may be useful in monitoring (patho) physiological changes. However, the application of breath monitoring in a non-controlled clinical setting introduces noise into the data. We hypothesized that the sensor signal is influenced by: (1) humidity in the side-stream; (2) patient-ventilator disconnections and the nebulization of medication; and (3) changes in ventilator settings and the amount of exhaled CO2. We aimed to explore whether the aforementioned factors introduce noise into the signal, and discuss several approaches to reduce this noise. Methods: Study in mechanically-ventilated ICU patients. Exhaled breath was monitored using a continuous eNose with metal oxide sensors. Linear (mixed) models were used to study hypothesized associations. Results: In total, 1251 h of eNose data were collected. First, the initial 15 min of the signal was discarded. There was a negative association between humidity and Sensor 1 (Fixed-effect β: −0.05 ± 0.002) and a positive association with Sensors 2–4 (Fixed-effect β: 0.12 ± 0.001); the signal was corrected for this noise. Outliers were most likely due to noise and therefore removed. Sensor values were positively associated with end-tidal CO2, tidal volume and the pressure variables. The signal was corrected for changes in these ventilator variables after which the associations disappeared. Conclusion: Variations in humidity, ventilator disconnections, nebulization of medication and changes of ventilator settings indeed influenced exhaled breath signals measured in ventilated patients by continuous eNose analysis. We discussed several approaches to reduce the effects of these noise inducing variables. PMID:27556467

  3. Assessment of quantum-chemical methods for electronic properties and geometry of signaling biomolecules.

    PubMed

    Ferro, Noel; Bredow, Thomas

    2010-04-15

    A reasonable balance between accuracy and feasibility of quantum-chemical methods depends on the complexity of the molecular system and the scientific goals. Six series of indole-, naphthalene-, phenol-, benzoic-, phenoxy-, other auxin-derivatives, and a test set of similar organic molecules have been chosen for an assessment of 13 density functional and semi-empirical molecular orbital methods with respect to electronic and structural properties. The accuracy and precision of HOMO/LUMO calculations are determined by comparison with experimental ionization potentials and electron affinities. Further comparison was performed at atomic level by covariance analysis. The methods KMLYP, MSINDO, and PM3 are precise and accurate for the whole set of molecules. The method AM1 offers comparable accuracy with the exception of electron affinities of indole derivatives, where significant deviations from experiment were observed. Geometrical properties were best reproduced with the semi-empirical method MSINDO. PMID:19899146

  4. Hydrated electrons react with high specificity with cisplatin bound to single-stranded DNA.

    PubMed

    Behmand, B; Cloutier, P; Girouard, S; Wagner, J R; Sanche, L; Hunting, D J

    2013-12-19

    Short oligonucleotides TTTTTGTGTTT and TTTTTTTGTTT in solution with and without cisplatin (cisPt) bound to the guanine bases were irradiated with γ-rays at doses varying from 0 to 2500 Gy. To determine the effect of hydrated electrons from water radiolysis on the oligonucleotides, we quenched (•)OH radicals with ethylenediaminetetraacetic acid (EDTA) and displaced oxygen, which reacts with hydrated electrons, by bubbling the solution with wet nitrogen. DNA strand breaks and platinum detachment were quantified by gel electrophoresis. Our results demonstrate that hydrated electrons react almost exclusively at the position of the cisPt adduct, where they induce cisPt detachment from one or both guanines in the oligonucleotide. Given the high yield of hydrated electrons in irradiated tissues, this reaction may be an important step in the mechanism of radiosensitization of DNA by cisPt.

  5. Hydrated Electrons React with High Specificity with Cisplatin Bound to Single-Stranded DNA

    PubMed Central

    Behmand, B.; Cloutier, P.; Girouard, S.; Wagner, J. R.; Sanche, L.; Hunting, D. J.

    2015-01-01

    Short oligonucleotides TTTTTGTGTTT and TTTTTTTGTTT in solution with and without cisplatin (cisPt) bound to the guanine bases were irradiated with γ-rays at doses varying from 0 to 2500 Gy. To determine the effect of hydrated electrons from water radiolysis on the oligonucleotides, we quenched •OH radicals with ethylenediaminetetraacetic acid (EDTA) and displaced oxygen, which reacts with hydrated electrons, by bubbling the solution with wet nitrogen. DNA strand breaks and platinum detachment were quantified by gel electrophoresis. Our results demonstrate that hydrated electrons react almost exclusively at the position of the cisPt adduct, where they induce cisPt detachment from one or both guanines in the oligonucleotide. Given the high yield of hydrated electrons in irradiated tissues, this reaction may be an important step in the mechanism of radiosensitization of DNA by cisPt. PMID:24205952

  6. The Influence of Modulated Signal Risetime in Flight Electronics Radiated Immunity Testing with a Mode-Stirred Chamber

    NASA Technical Reports Server (NTRS)

    Ely, Jay J.; Nguyen, Truong X.; Scearce, Stephen A.

    2000-01-01

    For electromagnetic immunity testing of an electronic system, it is desirable to demonstrate its functional integrity when exposed to the full range and intensity of environmental electromagnetic threats that may be encountered over its operational life. As part of this, it is necessary to show proper system operation when exposed to representative threat signal modulations. Modulated signal transition time is easily overlooked, but can be highly significant to system susceptibility. Radiated electromagnetic field immunity testing is increasingly being performed in Mode Stirred Chambers. Because the peak field vs. time relationship is affected by the operation of a reverberating room, it is important to understand how the room may influence any input signal modulation characteristics. This paper will provide insight into the field intensity vs. time relationship within the test environment of a mode stirred chamber. An understanding of this relationship is important to EMC engineers in determining what input signal modulation characteristics will be transferred to the equipment under test. References will be given for the development of this topic, and experimental data will be presented

  7. High-Resolution and Specific Detection of Bacteria on Complex Surfaces Using Nanoparticle Probes and Electron Microscopy

    PubMed Central

    Ye, Jun; Nielsen, Shaun; Joseph, Stephen; Thomas, Torsten

    2015-01-01

    The study of the interaction of bacteria with surfaces requires the detection of specific bacterial groups with high spatial resolution. Here, we describe a method to rapidly and efficiently add nanogold particles to oligonucleotide probes, which target bacterial ribosomal RNA. These nanogold-labeled probes are then used in an in situ hybridization procedure that ensures both cellular integrity and high specificity. Electron microscopy subsequently enables the visualization of specific cells with high local precision on complex surface structures. This method will contribute to an increased understanding of how bacteria interact with surface structures on a sub-micron scale. PMID:26018431

  8. High-resolution and specific detection of bacteria on complex surfaces using nanoparticle probes and electron microscopy.

    PubMed

    Ye, Jun; Nielsen, Shaun; Joseph, Stephen; Thomas, Torsten

    2015-01-01

    The study of the interaction of bacteria with surfaces requires the detection of specific bacterial groups with high spatial resolution. Here, we describe a method to rapidly and efficiently add nanogold particles to oligonucleotide probes, which target bacterial ribosomal RNA. These nanogold-labeled probes are then used in an in situ hybridization procedure that ensures both cellular integrity and high specificity. Electron microscopy subsequently enables the visualization of specific cells with high local precision on complex surface structures. This method will contribute to an increased understanding of how bacteria interact with surface structures on a sub-micron scale.

  9. A cytoplasmic activator of DNA replication is involved in signal transduction in antigen-specific T cell lines.

    PubMed

    Wong, R L; Clark, R B; Gutowski, J K; Katz, M E; Fresa, K L; Cohen, S

    1990-05-01

    Cytoplasmic extracts prepared from T cell lines undergoing antigen-specific, interleukin-2 (IL-2)-dependent proliferation were tested for their ability to induce DNA synthesis in isolated, quiescent nuclei. A tetanus toxoid (TET)-specific T cell line, established from peripheral blood of a normal human volunteer, was stimulated in the presence of relevant antigen and 1 unit/ml IL-2. Cytoplasmic extracts prepared from these cells were capable of inducing DNA synthesis in isolated, quiescent nuclei. The ability of cytoplasmic extracts to induce DNA synthesis in isolated, quiescent nuclei. The ability of cytoplasmic extracts to induce DNA synthesis in isolated nuclei correlated positively with the degree of proliferation induced in these cells. In contrast, incubation of this T cell line in the absence of antigen failed to induce proliferation and cytoplasmic extracts prepared from these cells induced little to no DNA synthesis in isolated, quiescent nuclei. The factor present in the cytoplasm of T cells stimulated with relevant antigen in the presence of IL-2 is similar, if not identical, to a factor which we have previously demonstrated in cytoplasmic extracts prepared from transformed lymphoblastoid cell lines and from mitogenically stimulated normal human peripheral blood mononuclear cells. This factor, which we have called activator of DNA replication (ADR) is a heat-labile protein, and is inactivated by treatment with protease inhibitors, including aprotinin. The ability of cytoplasmic extracts from T cells undergoing antigen-specific, IL-2-dependent proliferation to induce DNA synthesis in isolated, quiescent nuclei was markedly inhibited in the presence of aprotinin, providing strong evidence that a cytoplasmic activator of DNA replication, ADR, is involved in the signal transduction process for antigen-specific, IL-2-dependent T cell proliferation. ADR may represent a common intracellular mediator of DNA synthesis in activated and transformed lymphocytes

  10. Investigation of non-specific signals in nanoporous flow-through and flow-over based sensors.

    PubMed

    Kumar, Neeraj; Froner, Elena; Guider, Romain; Scarpa, Marina; Bettotti, Paolo

    2014-03-21

    Porous materials are ideal hosts to fabricate high sensitivity devices. Their large specific area and the possibility to modify the type and the strength of the matrix-analyte interactions allow the realization of sensors with finely tailored characteristics. In this article, we investigate how mass transport across the nanoporous structure influences the response due to the non-specific signal by comparing flow-through versus flow-over geometries. We observed a systematic overestimation of the sensitivity for porous substrate devices made of closed-ended pores compared with open-ended pore ones. Our analysis shows that such an effect is due to (unbound) analytes or contaminants that remain trapped within the pores and are not removed by rinsing of the sample. This result was verified by measuring similar samples in both flow through and flow over configurations, as well as their residual response after blockage of all their active sites. We also notice that sensors based on free-standing membranes show similar results independent of the fact that mass transport is induced by either an external pressure source or simply by Brownian motions.

  11. Single-Cell Analysis Reveals that Insulation Maintains Signaling Specificity between Two Yeast MAPK Pathways with Common Components

    PubMed Central

    Patterson, Jesse C.; Klimenko, Evguenia S.; Thorner, Jeremy

    2014-01-01

    Eukaryotic cells use multiple mitogen-activated protein kinase (MAPK) cascades to evoke appropriate responses to external stimuli. In Saccharomyces cerevisiae, the MAPK Fus3 is activated by pheromone-binding G protein-coupled receptors to promote mating, whereas the MAPK Hog1 is activated by hyperosmotic stress to elicit the high osmolarity glycerol (HOG) response. Although these MAPK pathways share several upstream components, exposure to either pheromone or osmolyte alone triggers only the appropriate response. We used fluorescent localization- and transcription-specific reporters to assess activation of these pathways in individual cells on the minute and hour timescale, respectively. Dual activation of these two MAPK pathways occurred over a broad range of stimulant concentrations and temporal regimes in wild-type cells subjected to co-stimulation. Thus, signaling specificity is achieved through an “insulation” mechanism, not a “cross-inhibition” mechanism. Furthermore, we showed that there was a critical period during which Hog1 activity had to occur for proper insulation of the HOG pathway. PMID:20959523

  12. Electronic Durability of Flexible Transparent Films from Type-Specific Single-Wall Carbon Nanotubes

    SciTech Connect

    Harris, J; Iyer, S; Bernhardt, A; Huh, JY; Hudson, S; Fagan, J; Hobbie, E.

    2011-12-11

    The coupling between mechanical flexibility and electronic performance is evaluated for thin films of metallic and semiconducting single-wall carbon nanotubes (SWCNTs) deposited on compliant supports. Percolated networks of type-purified SWCNTs are assembled as thin conducting coatings on elastic polymer substrates, and the sheet resistance is measured as a function of compression and cyclic strain through impedance spectroscopy. The wrinkling topography, microstructure and transparency of the films are independently characterized using optical microscopy, electron microscopy, and optical absorption spectroscopy. Thin films made from metallic SWCNTs show better durability as flexible transparent conductive coatings, which we attribute to a combination of superior mechanical performance and higher interfacial conductivity.

  13. Capturing season-specific precipitation signals in the northern Rocky Mountains, USA, using earlywood and latewood tree rings

    NASA Astrophysics Data System (ADS)

    Crawford, Christopher J.; Griffin, Daniel; Kipfmueller, Kurt F.

    2015-03-01

    Douglas-fir (Pseudotsuga menziesii Mirb. Franco) total width, earlywood, and latewood tree ring chronologies were developed from six lower forest border sites in the northern Rocky Mountain region of central Idaho and southwestern Montana, USA, to assess the potential for season-specific moisture reconstructions. These long-lived arid-site trees share strong between-tree and between-site coherence, and subannual tree ring chronologies reliably span the past seven centuries. Mapping spatiotemporal patterns in northern Rocky Mountain precipitation highlighted winter- and summer-dominated precipitation regimes that transition along a west to east gradient. When Douglas-fir tree rings were compared with instrumental climate records, season-specific correlations emerged between earlywood and latewood. Total width, earlywood, and latewood shared the most statistically significant monthly correlations with April-June precipitation, whereas variability in adjusted latewood was tuned to June-August precipitation. Principal component analysis indicated that the leading mode of common variance for earlywood and adjusted latewood explained 65% and 55% variance in the chronologies, respectively. Pearson's correlations between earlywood principal component one and the northern Rocky Mountain precipitation field showed that annual (July-June) and spring (April-June) precipitation exhibited the strongest pattern of significance in central Idaho and southwestern Montana valleys and the Snake River Plain. Summer precipitation (June-August) was correlated with adjusted latewood principal component one and was particularly pronounced along and east of the continental divide in southwestern Montana. These results indicate that Douglas-fir earlywood and adjusted latewood tree rings in the northern Rocky Mountains retain season-specific precipitation signals and may be helpful for studying historical precipitation within the winter-summer transition zone.

  14. 45 CFR 170.205 - Content exchange standards and implementation specifications for exchanging electronic health...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... submission to immunization registries—(1) Standard. HL7 2.3.1 (incorporated by reference in § 170.299). Implementation specifications. Implementation Guide for Immunization Data Transactions using Version 2.3.1 of the... specifications. HL7 2.5.1 Implementation Guide for Immunization Messaging Release 1.0 (incorporated by...

  15. 45 CFR 170.205 - Content exchange standards and implementation specifications for exchanging electronic health...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... submission to immunization registries. (1) Standard. HL7 2.3.1 (incorporated by reference in § 170.299). Implementation specifications. Implementation Guide for Immunization Data Transactions using Version 2.3.1 of the... specifications. HL7 2.5.1 Implementation Guide for Immunization Messaging Release 1.0 (incorporated by...

  16. 45 CFR 170.205 - Content exchange standards and implementation specifications for exchanging electronic health...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... submission to immunization registries—(1) Standard. HL7 2.3.1 (incorporated by reference in § 170.299). Implementation specifications. Implementation Guide for Immunization Data Transactions using Version 2.3.1 of the... specifications. HL7 2.5.1 Implementation Guide for Immunization Messaging Release 1.0 (incorporated by...

  17. Measurement of reflectivity of spherically bent crystals using Kα signal from hot electrons produced by laser-matter interaction

    SciTech Connect

    Antonelli, L.; Forestier-Colleoni, P.; Folpini, G.; Bouillaud, R.; Fedeli, L.; Fourment, C.; Giuffrida, L.; Hulin, S.; Santos, J. J.; Volpe, L.; Batani, D.; Faenov, A.; Pikuz, S.

    2015-07-15

    In an experiment at the laser facility ECLIPSE of the CELIA laboratory, University of Bordeaux, we measure the reflectivity of spherically bent crystals that are commonly used to investigate the propagation of fast electrons through the Kα radiation they generate in matter. The experimental reflectivity compares well with predictions from a ray-tracing code that takes into account the specific geometry, although the crystals seem to suffer from aging problems.

  18. Probing the spin state of a single electron trap by random telegraph signal.

    PubMed

    Xiao, M; Martin, I; Jiang, H W

    2003-08-15

    We have studied the random telegraph signal (RTS) generated by a single paramagnetic spin center adjacent to a submicrometer silicon metal-oxide-semiconductor field-effect transistor. An in-plane magnetic field induces a substantial change in the statistics of the RTS. We show that a model using the grand partition theorem can qualitatively explain the change in statistics of the RTS as a function of the applied magnetic field. While the data at high temperatures can be well described by this simple model, quantitative discrepancy increases as the temperature is lowered. PMID:12935055

  19. Electronic constant current and current pulse signal generator for nuclear instrumentation testing

    DOEpatents

    Brown, Roger A.

    1994-01-01

    Circuitry for testing the ability of an intermediate range nuclear instrut to detect and measure a constant current and a periodic current pulse. The invention simulates the resistance and capacitance of the signal connection of a nuclear instrument ion chamber detector and interconnecting cable. An LED flasher/oscillator illuminates an LED at a periodic rate established by a timing capacitor and circuitry internal to the flasher/oscillator. When the LED is on, a periodic current pulse is applied to the instrument. When the LED is off, a constant current is applied. An inductor opposes battery current flow when the LED is on.

  20. Electronic constant current and current pulse signal generator for nuclear instrumentation testing

    DOEpatents

    Brown, R.A.

    1994-04-19

    Circuitry is described for testing the ability of an intermediate range nuclear instrument to detect and measure a constant current and a periodic current pulse. The invention simulates the resistance and capacitance of the signal connection of a nuclear instrument ion chamber detector and interconnecting cable. An LED flasher/oscillator illuminates an LED at a periodic rate established by a timing capacitor and circuitry internal to the flasher/oscillator. When the LED is on, a periodic current pulse is applied to the instrument. When the LED is off, a constant current is applied. An inductor opposes battery current flow when the LED is on. 1 figures.

  1. Zero-field signal in the electron paramagnetic resonance spectrum of Mn{sup +2} in silicate glasses

    SciTech Connect

    Rakhimov, Rakhim R.; Jones, David E.

    2000-07-22

    A 9.4-9.8 GHz electron paramagnetic resonance (EPR) study of Mn{sup +2}-doped Na{sub 2}O-CaO-MgO-SiO{sub 2} glasses has revealed a nonresonant microwave magneto-absorption near zero magnetic field in addition to normal paramagnetic absorption due to Mn{sup +2} ions, electron spin S=5/2. The low-field response has an opposite phase relative to paramagnetic signal and is independent of the mutual orientation of the magnetic field of the microwave H{sub 1} and static magnetic field H. In contrast, the paramagnetic signal is different for perpendicular H{sub 1}(perpendicular sign)H and parallel H{sub 1}(parallel sign)H polarization of the microwave field, which is attributed to enhancement of forbidden magnetic dipolar transitions and suppression of the allowed transitions for parallel polarization. The low-field response is described in terms of microwave dielectric losses that derive from the magneto-induced charge migration in the first coordination sphere of Mn{sup +2}. As opposed to the spin-polarized tunneling that was described in ferromagnets between different valence forms of Mn, the observed effect is due to spin-dependent tunneling that occurs in the vicinity of Mn{sup +2} in a diluted paramagnetic system. (c) 2000 American Institute of Physics.

  2. Electron Anisotropy as a Signature of Mode Specific Isomerization in Vinylidene

    NASA Astrophysics Data System (ADS)

    Gibson, Stephen T.; Laws, Benjamin A.; Mabbs, Richard; Neumark, Daniel; Lineberger, Carl; Field, Robert W.

    2016-06-01

    he nature of the isomerization process that turns vinylidene into acetylene has been awaiting advances in experimental methods, to better define fractionation widths beyond those available in the seminal 1989 photoelectron spectrum measurement. This has proven a challenge. The technique of velocity-map imaging (VMI) is one avenue of approach. Images of electrons photodetached from vinylidene negative-ions, at various wavelengths, 1064 nm shown, provide more detail, including unassigned structure, but only an incremental improvement in the instrument line width. Intriguingly, the VMIs demonstrate a mode dependent variation in the electron anisotropy. Most notable in the figure, the inner-ring transition clusters are discontinuously, more isotropic. Electron anisotropy may provide an alternative key to examine the character of vinylidene transitions, mediating the necessity for an extreme resolution measurement. Vibrational dependent anisotropy has previously been observed in diatomic photoelectron spectra, associated with the coupling of electronic and nuclear motions. Research supported by the Australian Research Council Discovery Project Grant DP160102585. K. M. Ervin, J. Ho, and W. C. Lineberger, J. Chem. Phys. 91, 5974 (1989). doi:10.1063/1.457415 M. van Duzor et al. J. Chem. Phys. 133, 174311 (2010). doi:10.1063/1.3493349

  3. 45 CFR 170.205 - Content exchange standards and implementation specifications for exchanging electronic health...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Surveillance (incorporated by reference in § 170.299). (e) Electronic submission to immunization registries—(1... Guide for Immunization Data Transactions using Version 2.3.1 of the Health Level Seven (HL7) Standard... Immunization Messaging Release 1.0 (incorporated by reference in § 170.299). (3) Standard. HL7...

  4. The transcriptional repressor ZBTB4 regulates EZH2 through a MicroRNA-ZBTB4-specificity protein signaling axis.

    PubMed

    Yang, Won Seok; Chadalapaka, Gayathri; Cho, Sung-Gook; Lee, Syng-Ook; Jin, Un-Ho; Jutooru, Indira; Choi, Kwangmin; Leung, Yuet-Kin; Ho, Shuk-Mei; Safe, Stephen; Kim, Kyounghyun

    2014-12-01

    ZBTB4 is a transcriptional repressor and examination of publically-available microarray data sets demonstrated an inverse relationship in the prognostic value and expression of ZBTB4 and the histone methyltransferase EZH2 in tumors from breast cancer patients. The possibility of functional interactions between EZH2 and ZBTB4 was investigated in breast cancer cells and the results showed that EZH2 is directly suppressed by ZBTB4 which in turn is regulated (suppressed) by miR-106b and other paralogues from the miR-17-92, miR-106b-25 and miR-106a-363 clusters that are highly expressed in breast and other tumors. ZBTB4 also acts a suppressor of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4, and RNA interference studies show that Sp proteins are required for EZH2 expression. The prediction analysis results from breast cancer patient array data sets confirm an association of Sp1-dependent EZH2 gene signature with decreased survival of breast cancer patients. Disruption of oncogenic miR-ZBTB4 signaling axis by anticancer agent such as betulinic acid that induce down-regulation of Sp proteins in breast cancer cells resulted in inhibition of tumor growth and colonization of breast cancer cells in a mouse model. Thus, EZH2 is reciprocally regulated by a novel signaling network consisting of Sp proteins, oncogenic miRs and ZBTB4, and modulation of this gene network is a novel therapeutic approach for treatment of breast cancer and possibly other cancers.

  5. A specific sorting signal is not required for the polarized secretion of newly synthesized proteins from cultured intestinal epithelial cells.

    PubMed

    Rindler, M J; Traber, M G

    1988-08-01

    Caco-2 cells, derived from human colon, have the morphological, functional, and biochemical properties of small intestinal epithelial cells. After infection with enveloped viruses, influenza virions assembled at the apical plasma membrane while vesicular stomatitis virus (VSV) particles appeared exclusively at the basolateral membrane, similar to the pattern observed in virus-infected Madin-Darby canine kidney (MDCK). When grown in Millicell filter chamber devices and labeled with [35S]methionine, Caco-2 monolayers released all of their radiolabeled secretory products preferentially into the basal chamber. Among the proteins identified were apolipoproteins AI and E, transferrin, and alpha-fetoprotein. No proteins were observed to be secreted preferentially from the apical cell surface. The lysosomal enzyme beta-hexosaminidase was also secreted primarily from the basolateral surface of the cells in the presence or absence of lysosomotropic drugs or tunicamycin, which inhibit the targetting of lysosomal enzymes to lysosomes. Neither of these drug treatments significantly affected the polarized secretion of other nonlysosomal proteins. In addition, growth hormone (GH), which is released in a nonpolar fashion from MDCK cells, was secreted exclusively from the basolateral membrane after transfection of Caco-2 cells with GH cDNA in a pSV2-based expression vector. Similar results were obtained in transient expression experiments and after selection of permanently transformed Caco-2 cells expressing GH. Since both beta-hexosaminidase and GH would be expected to lack sorting signals for polarized exocytosis in epithelial cells, these results indicate that in intestinal cells, proteins transported via the basolateral secretory pathway need not have specific sorting signals.

  6. Plasma 25-Hydroxyvitamin D Is Related to Protein Signaling Involved in Glucose Homeostasis in a Tissue-Specific Manner

    PubMed Central

    Parker, Lewan; Levinger, Itamar; Mousa, Aya; Howlett, Kirsten; de Courten, Barbora

    2016-01-01

    Vitamin D has been suggested to play a role in glucose metabolism. However, previous findings are contradictory and mechanistic pathways remain unclear. We examined the relationship between plasma 25-hydroxyvitamin D (25(OH)D), insulin sensitivity, and insulin signaling in skeletal muscle and adipose tissue. Seventeen healthy adults (Body mass index: 26 ± 4; Age: 30 ± 12 years) underwent a hyperinsulinemic-euglycemic clamp, and resting skeletal muscle and adipose tissue biopsies. In this cohort, the plasma 25(OH)D concentration was not associated with insulin sensitivity (r = 0.19, p = 0.56). However, higher plasma 25(OH)D concentrations correlated with lower phosphorylation of glycogen synthase kinase-3 (GSK-3) αSer21 and βSer9 in skeletal muscle (r = −0.66, p = 0.015 and r = −0.53, p = 0.06, respectively) and higher GSK-3 αSer21 and βSer9 phosphorylation in adipose tissue (r = 0.82, p < 0.01 and r = 0.62, p = 0.042, respectively). Furthermore, higher plasma 25(OH)D concentrations were associated with greater phosphorylation of both protein kinase-B (AktSer473) (r = 0.78, p < 0.001) and insulin receptor substrate-1 (IRS-1Ser312) (r = 0.71, p = 0.01) in adipose tissue. No associations were found between plasma 25(OH)D concentration and IRS-1Tyr612 phosphorylation in skeletal muscle and adipose tissue. The divergent findings between muscle and adipose tissue with regard to the association between 25(OH)D and insulin signaling proteins may suggest a tissue-specific interaction with varying effects on glucose homeostasis. Further research is required to elucidate the physiological relevance of 25(OH)D in each tissue. PMID:27754361

  7. Alkaline-stress response in Glycine soja leaf identifies specific transcription factors and ABA-mediated signaling factors.

    PubMed

    Ge, Ying; Li, Yong; Lv, De-Kang; Bai, Xi; Ji, Wei; Cai, Hua; Wang, Ao-Xue; Zhu, Yan-Ming

    2011-06-01

    Transcriptome of Glycine soja leaf tissue during a detailed time course formed a foundation for examining transcriptional processes during NaHCO(3) stress treatment. Of a total of 2,310 detected differentially expressed genes, 1,664 genes were upregulated and 1,704 genes were downregulated at various time points. The number of stress-regulated genes increased dramatically after a 6-h stress treatment. GO category gene enrichment analysis revealed that most of the differentially expressed genes were involved in cell structure, protein synthesis, energy, and secondary metabolism. Another enrichment test revealed that the response of G. soja to NaHCO(3) highlights specific transcription factors, such as the C2C2-CO-like, MYB-related, WRKY, GARP-G2-like, and ZIM families. Co-expressed genes were clustered into ten classes (P < 0.001). Intriguingly, one cluster of 188 genes displayed a unique expression pattern that increases at an early stage (0.5 and 3 h), followed by a decrease from 6 to 12 h. This group was enriched in regulation of transcription components, including AP2-EREBP, bHLH, MYB/MYB-related, C2C2-CO-like, C2C2-DOF, C2C2, C3H, and GARP-G2-like transcription factors. Analysis of the 1-kb upstream regions of transcripts displaying similar changes in abundance identified 19 conserved motifs, potential binding sites for transcription factors. The appearance of ABA-responsive elements in the upstream of co-expression genes reveals that ABA-mediated signaling participates in the signal transduction in alkaline response.

  8. Characterization and mitigation of coherent-optical-transition-radiation signals from a compressed electron beam

    NASA Astrophysics Data System (ADS)

    Lumpkin, A. H.; Sereno, N. S.; Berg, W. J.; Borland, M.; Li, Y.; Pasky, S. J.

    2009-08-01

    The Advanced Photon Source (APS) injector complex includes an option for rf photocathode (PC) gun beam injection into the 450-MeV S-band linac. At the 150-MeV point, a four-dipole chicane was used to compress the micropulse bunch length from a few ps to sub-0.5 ps (FWHM). Noticeable enhancements of the optical transition radiation (OTR) signal sampled after the APS chicane were then observed as has been reported in the Linac Coherent Light Source (LCLS) injector commissioning. A far-infrared (FIR) coherent transition radiation detector and interferometer were used to monitor the bunch compression process and correlate the appearance of localized spikes of OTR signal (5 to 10 times brighter than adjacent areas) within the beam-image footprint. We have performed spectral-dependency measurements at 375 MeV with a series of bandpass filters centered in 50-nm increments from 400 to 700 nm and with an imaging spectrometer and observed a broadband enhancement in these spikes. Mitigation concepts of the observed coherent OTR, which exhibits an intensity enhancement in the red part of the visible spectrum as compared to incoherent OTR, are described.

  9. Characterization and mitigation of coherent optical transition radiation signal from a compressed electron beam.

    SciTech Connect

    Lumpkin, A. H.; Sereno, N. S.; Berg, W.; Borland, M.; Li, Y.; Pasky, S. )

    2009-01-01

    The Advanced Photon Source (APS) injector complex includes an option for rf photocathode (PC) gun beam injection into the 450-MeV S-band linac. At the 150-MeV point, a four-dipole chicane was used to compress the micropulse bunch length from a few ps to sub-0.5 ps (FWHM). Noticeable enhancements of the optical transition radiation (OTR) signal sampled after the APS chicane were then observed as has been reported in the Linac Coherent Light Source (LCLS) injector commissioning. A far-infrared (FIR) coherent transition radiation detector and interferometer were used to monitor the bunch compression process and correlate the appearance of localized spikes of OTR signal (5 to 10 times brighter than adjacent areas) within the beam-image footprint. We have performed spectral-dependency measurements at 375 MeV with a series of bandpass filters centered in 50-nm increments from 400 to 700 nm and with an imaging spectrometer and observed a broadband enhancement in these spikes. Mitigation concepts of the observed coherent OTR, which exhibits an intensity enhancement in the red part of the visible spectrum as compared to incoherent OTR, are described.

  10. Specificity of herbivore-induced hormonal signaling and defensive traits in five closely related milkweeds (Asclepias spp.).

    PubMed

    Agrawal, Anurag A; Hastings, Amy P; Patrick, Eamonn T; Knight, Anna C

    2014-07-01

    Despite the recognition that phytohormonal signaling mediates induced responses to herbivory, we still have little understanding of how such signaling varies among closely related species and may generate herbivore-specific induced responses. We studied closely related milkweeds (Asclepias) to link: 1) plant damage by two specialist chewing herbivores (milkweed leaf beetles Labidomera clivicolis and monarch caterpillars Danaus plexippus); 2) production of the phytohormones jasmonic acid (JA), salicylic acid (SA), and abscisic acid (ABA); 3) induction of defensive cardenolides and latex; and 4) impacts on Danaus caterpillars. We first show that A. syriaca exhibits induced resistance following monarch herbivory (i.e., reduced monarch growth on previously damaged plants), while the defensively dissimilar A. tuberosa does not. We next worked with a broader group of five Asclepias, including these two species, that are highly divergent in defensive traits yet from the same clade. Three of the five species showed herbivore-induced changes in cardenolides, while induced latex was found in four species. Among the phytohormones, JA and ABA showed specific responses (although they generally increased) to insect species and among the plant species. In contrast, SA responses were consistent among plant and herbivore species, showing a decline following herbivore attack. Jasmonic acid showed a positive quantitative relationship only with latex, and this was strongest in plants damaged by D. plexippus. Although phytohormones showed qualitative tradeoffs (i.e., treatments that enhanced JA reduced SA), the few significant individual plant-level correlations among hormones were positive, and these were strongest between JA and ABA in monarch damaged plants. We conclude that: 1) latex exudation is positively associated with endogenous JA levels, even among low-latex species; 2) correlations among milkweed hormones are generally positive, although herbivore damage induces a

  11. Neutrino Signal of Electron-Capture Supernovae from Core Collapse to Cooling

    SciTech Connect

    Huedepohl, L.; Mueller, B.; Janka, H.-T.; Marek, A.; Raffelt, G. G.

    2010-06-25

    An 8.8M{sub {center_dot}}electron-capture supernova was simulated in spherical symmetry consistently from collapse through explosion to essentially complete deleptonization of the forming neutron star. The evolution time ({approx}9 s) is short because high-density effects suppress our neutrino opacities. After a short phase of accretion-enhanced luminosities ({approx}200 ms), luminosity equipartition among all species becomes almost perfect and the spectra of {nu}{sub e} and {nu}{sub {mu},{tau}}very similar, ruling out the neutrino-driven wind as r-process site. We also discuss consequences for neutrino flavor oscillations.

  12. Neutrino signal of electron-capture supernovae from core collapse to cooling.

    PubMed

    Hüdepohl, L; Müller, B; Janka, H-T; Marek, A; Raffelt, G G

    2010-06-25

    An 8.8M{⊙} electron-capture supernova was simulated in spherical symmetry consistently from collapse through explosion to essentially complete deleptonization of the forming neutron star. The evolution time (∼9  s) is short because high-density effects suppress our neutrino opacities. After a short phase of accretion-enhanced luminosities (∼200  ms), luminosity equipartition among all species becomes almost perfect and the spectra of ν{e} and ν{μ,τ} very similar, ruling out the neutrino-driven wind as r-process site. We also discuss consequences for neutrino flavor oscillations.

  13. Standard Electronic Format Specification for Tank Characterization Data Loader Version 3.0

    SciTech Connect

    ADAMS, M.R.

    1999-08-12

    The purpose of this document is to describe the standard electronic format for data files that will be sent for entry into the Tank Characterization Database (TCD). There are 2 different file types needed for each data load: Analytical Results; and Sample Descriptions. The first record of each file must be a header record. The content of the first 5 fields is ignored. They were used previously to satisfy historic requirements that are no longer applicable. The sixth field of the header record must contain the Standard Electronic Format (SEF) version ID (SEF3.0). The remaining records will be formatted as specified below. Fields within a record will be separated using the ''|'' symbol. The ''|''symbol must not appear anywhere in the file except when used as a delimiter.

  14. MO-H-19A-03: Patient Specific Bolus with 3D Printing Technology for Electron Radiotherapy

    SciTech Connect

    Zou, W; Swann, B; Siderits, R; McKenna, M; Khan, A; Yue, N; Zhang, M; Fisher, T

    2014-06-15

    Purpose: Bolus is widely used in electron radiotherapy to achieve desired dose distribution. 3D printing technologies provide clinicians with easy access to fabricate patient specific bolus accommodating patient body surface irregularities and tissue inhomogeneity. This study presents the design and the clinical workflow of 3D printed bolus for patient electron therapy in our clinic. Methods: Patient simulation CT images free of bolus were exported from treatment planning system (TPS) to an in-house developed software package. Bolus with known material properties was designed in the software package and then exported back to the TPS as a structure. Dose calculation was carried out to examine the coverage of the target. After satisfying dose distribution was achieved, the bolus structure was transferred in Standard Tessellation Language (STL) file format for the 3D printer to generate the machine codes for printing. Upon receiving printed bolus, a quick quality assurance was performed with patient resimulated with bolus in place to verify the bolus dosimetric property before treatment started. Results: A patient specific bolus for electron radiotherapy was designed and fabricated in Form 1 3D printer with methacrylate photopolymer resin. Satisfying dose distribution was achieved in patient with bolus setup. Treatment was successfully finished for one patient with the 3D printed bolus. Conclusion: The electron bolus fabrication with 3D printing technology was successfully implemented in clinic practice.

  15. Cloud-based Electronic Health Records for Real-time, Region-specific Influenza Surveillance

    PubMed Central

    Santillana, M.; Nguyen, A. T.; Louie, T.; Zink, A.; Gray, J.; Sung, I.; Brownstein, J. S.

    2016-01-01

    Accurate real-time monitoring systems of influenza outbreaks help public health officials make informed decisions that may help save lives. We show that information extracted from cloud-based electronic health records databases, in combination with machine learning techniques and historical epidemiological information, have the potential to accurately and reliably provide near real-time regional estimates of flu outbreaks in the United States. PMID:27165494

  16. Site-Specific Chemical Surface Functionalization and Electronic Patterning of Graphene by Electrooxidative Lithography.

    PubMed

    Liu, He; Hoeppener, Stephanie; Schubert, Ulrich S

    2016-09-19

    The combination of different properties being manipulated on nanomaterials is one of the challenges in nanotechnology research. In particular, the possibility to tailor the electronic and chemical properties offers promising possibilities for the design of functional nanostructures. Herein, we report an approach that permits control of these properties on the basis of electrooxidative lithography to structure reduced graphene oxide functionalized with a self-assembled monolayer of n-octadecyltrichlorosilane. The electrochemical oxidation process first induces the formation of polar acid groups on the monolayer, which can be used to covalently bind nanoparticles and molecules and, secondly, also allows the reoxidation of the underlying reduced graphene oxide. As such, the chemical signature as well as the electronic properties of the substrate can be tailored on the micro- and nanometer scale. Details on the oxidation of the monolayer as well as thorough characterization of the electronic properties will be presented. Finally, the approach is used to demonstrate the fabrication of a sensitive glucose sensor device.

  17. Site-Specific Chemical Surface Functionalization and Electronic Patterning of Graphene by Electrooxidative Lithography.

    PubMed

    Liu, He; Hoeppener, Stephanie; Schubert, Ulrich S

    2016-09-19

    The combination of different properties being manipulated on nanomaterials is one of the challenges in nanotechnology research. In particular, the possibility to tailor the electronic and chemical properties offers promising possibilities for the design of functional nanostructures. Herein, we report an approach that permits control of these properties on the basis of electrooxidative lithography to structure reduced graphene oxide functionalized with a self-assembled monolayer of n-octadecyltrichlorosilane. The electrochemical oxidation process first induces the formation of polar acid groups on the monolayer, which can be used to covalently bind nanoparticles and molecules and, secondly, also allows the reoxidation of the underlying reduced graphene oxide. As such, the chemical signature as well as the electronic properties of the substrate can be tailored on the micro- and nanometer scale. Details on the oxidation of the monolayer as well as thorough characterization of the electronic properties will be presented. Finally, the approach is used to demonstrate the fabrication of a sensitive glucose sensor device. PMID:27387745

  18. Muscle-specific 4E-BP1 signaling activation improves metabolic parameters during aging and obesity

    PubMed Central

    Tsai, Shihyin; Sitzmann, Joanna M.; Dastidar, Somasish G.; Rodriguez, Ariana A.; Vu, Stephanie L.; McDonald, Circe E.; Academia, Emmeline C.; O’Leary, Monique N.; Ashe, Travis D.; La Spada, Albert R.; Kennedy, Brian K.

    2015-01-01

    Eukaryotic translation initiation factor 4E–binding protein 1 (4E-BP1) is a key downstream effector of mTOR complex 1 (mTORC1) that represses cap-dependent mRNA translation initiation by sequestering the translation initiation factor eIF4E. Reduced mTORC1 signaling is associated with life span extension and improved metabolic homeostasis, yet the downstream targets that mediate these benefits are unclear. Here, we demonstrated that enhanced 4E-BP1 activity in mouse skeletal muscle protects against age- and diet-induced insulin resistance and metabolic rate decline. Transgenic animals displayed increased energy expenditure; altered adipose tissue distribution, including reduced white adipose accumulation and preserved brown adipose mass; and were protected from hepatic steatosis. Skeletal muscle–specific 4E-BP1 mediated metabolic protection directly through increased translation of peroxisome proliferator–activated receptor γ coactivator-1α (PGC-1α) and enhanced respiratory function. Non–cell autonomous protection was through preservation of brown adipose tissue metabolism, which was increased in 4E-BP1 transgenic animals during normal aging and in a response to diet-induced type 2 diabetes. Adipose phenotypes may derive from enhanced skeletal muscle expression and secretion of the known myokine FGF21. Unlike skeletal muscle, enhanced adipose-specific 4E-BP1 activity was not protective but instead was deleterious in response to the same challenges. These findings indicate that regulation of 4E-BP1 in skeletal muscle may serve as an important conduit through which mTORC1 controls metabolism. PMID:26121750

  19. Evolutionary Genomics Suggests That CheV Is an Additional Adaptor for Accommodating Specific Chemoreceptors within the Chemotaxis Signaling Complex.

    PubMed

    Ortega, Davi R; Zhulin, Igor B

    2016-02-01

    Escherichia coli and Salmonella enterica are models for many experiments in molecular biology including chemotaxis, and most of the results obtained with one organism have been generalized to another. While most components of the chemotaxis pathway are strongly conserved between the two species, Salmonella genomes contain some chemoreceptors and an additional protein, CheV, that are not found in E. coli. The role of CheV was examined in distantly related species Bacillus subtilis and Helicobacter pylori, but its role in bacterial chemotaxis is still not well understood. We tested a hypothesis that in enterobacteria CheV functions as an additional adaptor linking the CheA kinase to certain types of chemoreceptors that cannot be effectively accommodated by the universal adaptor CheW. Phylogenetic profiling, genomic context and comparative protein sequence analyses suggested that CheV interacts with specific domains of CheA and chemoreceptors from an orthologous group exemplified by the Salmonella McpC protein. Structural consideration of the conservation patterns suggests that CheV and CheW share the same binding spot on the chemoreceptor structure, but have some affinity bias towards chemoreceptors from different orthologous groups. Finally, published experimental results and data newly obtained via comparative genomics support the idea that CheV functions as a "phosphate sink" possibly to off-set the over-stimulation of the kinase by certain types of chemoreceptors. Overall, our results strongly suggest that CheV is an additional adaptor for accommodating specific chemoreceptors within the chemotaxis signaling complex.

  20. Evolutionary genomics suggests that CheV is an additional adaptor for accommodating specific chemoreceptors within the chemotaxis signaling complex

    DOE PAGES

    Ortega, Davi R.; Zhulin, Igor B.; Punta, Marco

    2016-02-04

    Escherichia coli and Salmonella enterica are models for many experiments in molecular biology including chemotaxis, and most of the results obtained with one organism have been generalized to another. While most components of the chemotaxis pathway are strongly conserved between the two species, Salmonella genomes contain some chemoreceptors and an additional protein, CheV, that are not found in E. coli. The role of CheV was examined in distantly related species Bacillus subtilis and Helicobacter pylori, but its role in bacterial chemotaxis is still not well understood. We tested a hypothesis that in enterobacteria CheV functions as an additional adaptor linkingmore » the CheA kinase to certain types of chemoreceptors that cannot be effectively accommodated by the universal adaptor CheW. Phylogenetic profiling, genomic context and comparative protein sequence analyses suggested that CheV interacts with specific domains of CheA and chemoreceptors from an orthologous group exemplified by the Salmonella McpC protein. Structural consideration of the conservation patterns suggests that CheV and CheW share the same binding spot on the chemoreceptor structure, but have some affinity bias towards chemoreceptors from different orthologous groups. Finally, published experimental results and data newly obtained via comparative genomics support the idea that CheV functions as a "phosphate sink" possibly to off-set the over-stimulation of the kinase by certain types of chemoreceptors. Altogether, our results strongly suggest that CheV is an additional adaptor for accommodating specific chemoreceptors within the chemotaxis signaling complex.« less

  1. RGS18 is a myeloerythroid lineage-specific regulator of G-protein-signalling molecule highly expressed in megakaryocytes.

    PubMed Central

    Yowe, D; Weich, N; Prabhudas, M; Poisson, L; Errada, P; Kapeller, R; Yu, K; Faron, L; Shen, M; Cleary, J; Wilkie, T M; Gutierrez-Ramos, C; Hodge, M R

    2001-01-01

    Myelopoiesis and lymphopoiesis are controlled by haematopoietic growth factors, including cytokines, and chemokines that bind to G-protein-coupled receptors (GPCRs). Regulators of G-protein signalling (RGSs) are a protein family that can act as GTPase-activating proteins for G(alphai)- and G(alphaq)-class proteins. We have identified a new member of the R4 subfamily of RGS proteins, RGS18. RGS18 contains clusters of hydrophobic and basic residues, which are characteristic of an amphipathic helix within its first 33 amino acids. RGS18 mRNA was most highly abundant in megakaryocytes, and was also detected specifically in haematopoietic progenitor and myeloerythroid lineage cells. RGS18 mRNA was not detected in cells of the lymphoid lineage. RGS18 was also highly expressed in mouse embryonic 15-day livers, livers being the principal organ for haematopoiesis at this stage of fetal development. RGS1, RGS2 and RGS16, other members of the R4 subfamily, were expressed in distinct progenitor and mature myeloerythroid and lymphoid lineage blood cells. RGS18 was shown to interact specifically with the G(alphai-3) subunit in membranes from K562 cells. Furthermore, overexpression of RGS18 inhibited mitogen-activated-protein kinase activation in HEK-293/chemokine receptor 2 cells treated with monocyte chemotactic protein-1. In yeast cells, RGS18 overexpression complemented a pheromone-sensitive phenotype caused by mutations in the endogeneous yeast RGS gene, SST2. These data demonstrated that RGS18 was expressed most highly in megakaryocytes, and can modulate GPCR pathways in both mammalian and yeast cells in vitro. Hence RGS18 might have an important role in the regulation of megakaryocyte differentiation and chemotaxis. PMID:11563974

  2. Cartilage-specific β-CATENIN signaling regulates chondrocyte maturation, generation of ossification centers, and perichondrial bone formation during skeletal development

    PubMed Central

    Dao, Debbie Y.; Jonason, Jennifer H.; Zhang, Yongchun; Hsu, Wei; Chen, Di; Hilton, Matthew J.; O’Keefe, Regis J.

    2012-01-01

    The WNT/β-CATENIN signaling pathway is a critical regulator of chondrocyte and osteoblast differentiation during multiple phases of cartilage and bone development. While the importance of β-CATENIN signaling during the process of endochondral bone development has been previously appreciated using a variety of genetic models that manipulate β-CATENIN in skeletal progenitors and osteoblasts, genetic evidence demonstrating a specific role for β-CATENIN in committed growth plate chondrocytes has been less robust. To identify the specific role of cartilage-derived β-CATENIN in regulating cartilage and bone development, we studied chondrocyte-specific gain- and loss-of-function genetic mouse models using the tamoxifen-inducible Col2CreERT2 transgene in combination with β-cateninfx(exon3)/wt or β-cateninfx/fx floxed alleles, respectively. From these genetic models and biochemical data, three significant and novel findings were uncovered. First, cartilage-specific β-CATENIN signaling promotes chondrocyte maturation, possibly involving a BMP2 mediated mechanism. Second, cartilage-specific β–CATENIN facilitates primary and secondary ossification center formation via the induction of chondrocyte hypertrophy, possibly through enhanced MMP expression at sites of cartilage degradation, and potentially by enhancing IHH signaling activity to recruit vascular tissues. Finally, cartilage-specific β-CATENIN signaling promotes perichondrial bone formation possibly via a mechanism in which BMP2 and IHH paracrine signals synergize to accelerate perichondrial osteoblastic differentiation. The work presented here supports the concept that the cartilage-derived β-CATENIN signal is a central mediator for major events during endochondral bone formation, including chondrocyte maturation, primary and secondary ossification center development, vascularization, and perichondrial bone formation. PMID:22508079

  3. Domain-Specific Activation of Death-Associated Intracellular Signalling Cascades by the Cellular Prion Protein in Neuroblastoma Cells.

    PubMed

    Vilches, Silvia; Vergara, Cristina; Nicolás, Oriol; Mata, Ágata; Del Río, José A; Gavín, Rosalina

    2016-09-01

    The biological functions of the cellular prion protein remain poorly understood. In fact, numerous studies have aimed to determine specific functions for the different protein domains. Studies of cellular prion protein (PrP(C)) domains through in vivo expression of molecules carrying internal deletions in a mouse Prnp null background have provided helpful data on the implication of the protein in signalling cascades in affected neurons. Nevertheless, understanding of the mechanisms underlying the neurotoxicity induced by these PrP(C) deleted forms is far from complete. To better define the neurotoxic or neuroprotective potential of PrP(C) N-terminal domains, and to overcome the heterogeneity of results due to the lack of a standardized model, we used neuroblastoma cells to analyse the effects of overexpressing PrP(C) deleted forms. Results indicate that PrP(C) N-terminal deleted forms were properly processed through the secretory pathway. However, PrPΔF35 and PrPΔCD mutants led to death by different mechanisms sharing loss of alpha-cleavage and activation of caspase-3. Our data suggest that both gain-of-function and loss-of-function pathogenic mechanisms may be associated with N-terminal domains and may therefore contribute to neurotoxicity in prion disease. Dissecting the molecular response induced by PrPΔF35 may be the key to unravelling the physiological and pathological functions of the prion protein. PMID:26250617

  4. Metformin Improves Insulin Signaling in Obese Rats via Reduced IKKbeta Action in a Fiber-Type Specific Manner.

    PubMed

    Bikman, Benjamin T; Zheng, Donghai; Kane, Daniel A; Anderson, Ethan J; Woodlief, Tracey L; Price, Jesse W; Dohm, G Lynis; Neufer, P Darrell; Cortright, Ronald N

    2010-01-01

    Metformin is a widely used insulin-sensitizing drug, though its mechanisms are not fully understood. Metformin has been shown to activate AMPK in skeletal muscle; however, its effects on the inhibitor of kappaB kinasebeta (IKKbeta) in this same tissue are unknown. The aim of this study was to (1) determine the ability of metformin to attenuate IKKbeta action, (2) determine whether changes in AMPK activity are associated with changes in IKKbeta action in skeletal muscle, and (3) examine whether changes in AMPK and IKKbeta function are consistent with improved insulin signaling. Lean and obese male Zuckers received either vehicle or metformin by oral gavage daily for four weeks (four groups of eight). Proteins were measured in white gastrocnemius (WG), red gastrocnemius (RG), and soleus. AMPK phosphorylation increased (P < .05) in WG in both lean (57%) and obese (106%), and this was supported by an increase in phospho-ACC in WG. Further, metformin increased IkappaBalpha levels in both WG (150%) and RG (67%) of obese rats, indicative of reduced IKKbeta activity (P < .05), and was associated with reduced IRS1-pSer(307) (30%) in the WG of obese rats (P < .02). From these data we conclude that metformin treatment appears to exert an inhibitory influence on skeletal muscle IKKbeta activity, as evidenced by elevated IkappaBalpha levels and reduced IRS1-Ser(307) phosphorylation in a fiber-type specific manner. PMID:20798864

  5. Fus3-regulated Tec1 degradation through SCFCdc4 determines MAPK signaling specificity during mating in yeast.

    PubMed

    Chou, Song; Huang, Lan; Liu, Haoping

    2004-12-29

    Signaling specificity is fundamental for parallel mitogen-activated protein kinase (MAPK) cascades that control growth and differentiation in response to different stimuli. In Saccharomyces cerevisiae, components of the pheromone-responsive MAPK cascade activate Fus3 and Kss1 MAPKs to induce mating and Kss1 to promote filamentation. Active Fus3 is required to prevent the activation of the filamentation program during pheromone response. How Fus3 prevents the crossactivation is not clear. Here we show that Tec1, a cofactor of Ste12 for the expression of filamentation genes, is rapidly degraded during pheromone response. Fus3 but not Kss1 induces Tec1 ubiquination and degradation through the SCFCdc4 ubiquitin ligase. T273 in a predicted high-affinity Cdc4 binding motif is phosphorylated by Fus3 both in vitro and in vivo. Tec1T273V blocks Tec1 ubiquitination and degradation and allows the induction of filamentation genes in response to pheromone. Thus, Fus3 inhibits filamentous growth during mating by degrading Tec1. PMID:15620356

  6. Microbial translocation augments the function of adoptively transferred self/tumor-specific CD8+ T cells via TLR4 signaling

    PubMed Central

    Paulos, Chrystal M.; Wrzesinski, Claudia; Kaiser,, Andrew; Hinrichs, Christian S.; Chieppa, Marcello; Cassard, Lydie; Palmer, Douglas C.; Boni, Andrea; Muranski, Pawel; Yu, Zhiya; Gattinoni, Luca; Antony, Paul A.; Rosenberg, Steven A.; Restifo, Nicholas P.

    2007-01-01

    Lymphodepletion with total body irradiation (TBI) increases the efficacy of adoptively transferred tumor-specific CD8+ T cells by depleting inhibitory lymphocytes and increasing homeostatic cytokine levels. We found that TBI augmented the function of adoptively transferred CD8+ T cells in mice genetically deficient in all lymphocytes, indicating the existence of another TBI mechanism of action. Additional investigation revealed commensal gut microflora in the mesenteric lymph nodes and elevated LPS levels in the sera of irradiated mice. These findings correlated with increased dendritic cell activation and heightened levels of systemic inflammatory cytokines. Reduction of host microflora using antibiotics, neutralization of serum LPS using polymyxin B, or removal of LPS signaling components using mice genetically deficient in CD14 and TLR4 reduced the beneficial effects of TBI on tumor regression. Conversely, administration of microbial ligand–containing serum or ultrapure LPS from irradiated animals to nonirradiated antibody-lymphodepleted mice enhanced CD8+ T cell activation and improved tumor regression. Administration of ultrapure LPS to irradiated animals further enhanced the number and function of the adoptively transferred cells, leading to long-term cure of mice with large B16F10 tumors and enhanced autoimmune vitiligo. Thus, disruption of the homeostatic balance between the host and microbes can enhance cell-based tumor immunotherapy. PMID:17657310

  7. A Recombinant Secondary Antibody Mimic as a Target-specific Signal Amplifier and an Antibody Immobilizer in Immunoassays.

    PubMed

    Min, Junseon; Song, Eun Kyung; Kim, Hansol; Kim, Kyoung Taek; Park, Tae Joo; Kang, Sebyung

    2016-01-01

    We construct a novel recombinant secondary antibody mimic, GST-ABD, which can bind to the Fc regions of target-bound primary antibodies and acquire multiple HRPs simultaneously. We produce it in tenth of mg quantities with a bacterial overexpression system and simple purification procedures, significantly reducing the manufacturing cost and time without the use of animals. GST-ABD is effectively conjugated with 3 HRPs per molecule on an average and selectively bind to the Fc region of primary antibodies derived from three different species (mouse, rabbit, and rat). HRP-conjugated GST-ABD (HRP-GST-ABD) is successfully used as an alternative to secondary antibodies to amplify target-specific signals in both ELISA and immunohistochemistry regardless of the target molecules and origin of primary antibodies used. GST-ABD also successfully serves as an anchoring adaptor on the surface of GSH-coated plates for immobilizing antigen-capturing antibodies in an orientation-controlled manner for sandwich-type indirect ELISA through simple molecular recognition without any complicated chemical modification. PMID:27063487

  8. New Approaches to Prevent LEOPARD Syndrome-associated Cardiac Hypertrophy by Specifically Targeting Shp2-dependent Signaling*

    PubMed Central

    Schramm, Christine; Edwards, Michelle A.; Krenz, Maike

    2013-01-01

    In LEOPARD syndrome (LS) patients, mutations in the protein tyrosine phosphatase Shp2 cause hypertrophic cardiomyopathy. The prohypertrophic effects of mutant Shp2 are mediated downstream by hyperactivation of mammalian target of rapamycin. Our goal was to further define the signaling cascade that is essential for the underlying pathomechanism, thus expanding the list of potential future therapeutic targets. Using cultured neonatal rat cardiomyocytes with adenoviral gene delivery and pharmacological inhibitors, we found that hypertrophy induced by a particularly aggressive LS mutation in Shp2 depends on hyperactivation of Akt and focal adhesion kinase as well as mammalian target of rapamycin. Dissecting domain-specific functions of Shp2 using double and truncation mutants, we determined that the hypertrophic effects of mutant Shp2 depend on the two SH2 domains and on an intact catalytic center. The latter finding prompted us to test the efficacy of a Shp2 inhibitor targeted directly at the catalytic pocket. This compound, PHPS1, effectively prevented mutant Shp2-induced hypertrophy. In summary, we identified three novel targets for pharmacological therapy of LS-associated cardiac hypertrophy. Of particular importance is the finding that intervention directly at the mutant Shp2 protein is effective because this would facilitate custom-tailored therapeutic approaches for patients carrying LS mutations in Shp2. PMID:23673659

  9. A sensitive electrochemical DNA biosensor for specific detection of Enterobacteriaceae bacteria by Exonuclease III-assisted signal amplification.

    PubMed

    Luo, Caihui; Tang, Hua; Cheng, Wei; Yan, Li; Zhang, Decai; Ju, Huangxian; Ding, Shijia

    2013-10-15

    A specific and sensitive methodology was developed successfully for quantitative detection of Enterobacteriaceae bacteria by integrating Exonuclease III-assisted target recycling amplification with a simple electrochemical DNA biosensor. After target DNA hybridizes with capture DNA, Exonuclease III can selectively digest the capture DNA, which releases the target to undergo a new hybridization and cleavage cycle on sensor surface, leading to a successful target recycling. Finally, the left capture DNA is recognized by detection probe to produce the detectable signal, which decreases with the increasing target DNA concentration. Under the optimal conditions, the proposed strategy could detect target DNA down to 8.7 fM with a linear range from 0.01 pM to 1 nM, showing high sensitivity. Meanwhile, the sensing strategy was successfully used for detection of Enterobacteriaceae bacteria down to 40 CFU mL⁻¹ in milk samples. This strategy presented a simple, rapid and sensitive platform for Enterobacteriaceae bacteria detection and would become a versatile and powerful tool for food safety, biothreat detection and environmental monitoring.

  10. A Recombinant Secondary Antibody Mimic as a Target-specific Signal Amplifier and an Antibody Immobilizer in Immunoassays

    PubMed Central

    Min, Junseon; Song, Eun Kyung; Kim, Hansol; Kim, Kyoung Taek; Park, Tae Joo; Kang, Sebyung

    2016-01-01

    We construct a novel recombinant secondary antibody mimic, GST-ABD, which can bind to the Fc regions of target-bound primary antibodies and acquire multiple HRPs simultaneously. We produce it in tenth of mg quantities with a bacterial overexpression system and simple purification procedures, significantly reducing the manufacturing cost and time without the use of animals. GST-ABD is effectively conjugated with 3 HRPs per molecule on an average and selectively bind to the Fc region of primary antibodies derived from three different species (mouse, rabbit, and rat). HRP-conjugated GST-ABD (HRP-GST-ABD) is successfully used as an alternative to secondary antibodies to amplify target-specific signals in both ELISA and immunohistochemistry regardless of the target molecules and origin of primary antibodies used. GST-ABD also successfully serves as an anchoring adaptor on the surface of GSH-coated plates for immobilizing antigen-capturing antibodies in an orientation-controlled manner for sandwich-type indirect ELISA through simple molecular recognition without any complicated chemical modification. PMID:27063487

  11. Domain-Specific Activation of Death-Associated Intracellular Signalling Cascades by the Cellular Prion Protein in Neuroblastoma Cells.

    PubMed

    Vilches, Silvia; Vergara, Cristina; Nicolás, Oriol; Mata, Ágata; Del Río, José A; Gavín, Rosalina

    2016-09-01

    The biological functions of the cellular prion protein remain poorly understood. In fact, numerous studies have aimed to determine specific functions for the different protein domains. Studies of cellular prion protein (PrP(C)) domains through in vivo expression of molecules carrying internal deletions in a mouse Prnp null background have provided helpful data on the implication of the protein in signalling cascades in affected neurons. Nevertheless, understanding of the mechanisms underlying the neurotoxicity induced by these PrP(C) deleted forms is far from complete. To better define the neurotoxic or neuroprotective potential of PrP(C) N-terminal domains, and to overcome the heterogeneity of results due to the lack of a standardized model, we used neuroblastoma cells to analyse the effects of overexpressing PrP(C) deleted forms. Results indicate that PrP(C) N-terminal deleted forms were properly processed through the secretory pathway. However, PrPΔF35 and PrPΔCD mutants led to death by different mechanisms sharing loss of alpha-cleavage and activation of caspase-3. Our data suggest that both gain-of-function and loss-of-function pathogenic mechanisms may be associated with N-terminal domains and may therefore contribute to neurotoxicity in prion disease. Dissecting the molecular response induced by PrPΔF35 may be the key to unravelling the physiological and pathological functions of the prion protein.

  12. Specific detection of mercury(II) irons using AlGaAs/InGaAs high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Wang, Chengyan; Zhang, Yang; Guan, Min; Cui, Lijie; Ding, Kai; Zhang, Bintian; Lin, Zhang; Huang, Feng; Zeng, Yiping

    2015-09-01

    As one of the most environmentally important cations, mercury(II) iron has the biological toxicity which impacts wild life ecology and human health heavily. A Hg2+ biosensor based on AlGaAs/InGaAs high electron mobility transistors with high sensitivity and short response time is demonstrated experimentally. To achieve highly specific detection of Hg2+, an one-end thiol-modified ssDNA with lots of T thymine is immobilized to the Au-coated gate area of the high electron mobility transistors by a covalent modification method. The introduction of Hg2+ to the gate of the high electron mobility transistors affects surface charges, which leads to a change in the concentration of the two-dimensional electron gas in the AlGaAs/InGaAs high electron mobility transistors. Thus, the saturation current curves can be shifted with the modification of the gate areas and varied concentrations of Hg2+. Under the bias of 100 mV, a detection limit for the Hg2+ as low as10 nM is achieved. Successful detection with minute quantity of the sample indicates that the sensor has great potential in practical screening for a wide population. In addition, the dimension of the active area of the sensor is 20×50 μm2 and that of the entire sensor chip is 1×2 mm2, which make the Hg2+ biosensor portable.

  13. Use of electron-trapping materials in optical signal processing. IV - Parallel incoherent image subtraction

    NASA Astrophysics Data System (ADS)

    Jutamulia, Suganda; Storti, George M.; Seiderman, William; Lindmayer, Joseph; Gregory, Don A.

    1993-02-01

    The application of electron trapping (ET) materials to parallel incoherent image subtraction over a wide dynamic range is examined in detail. A new incoherent image-subtraction technique based on ET materials is presented which can be applied to automation for microcircuit manufacture and inspection and potentially to data compression for videophones, teleconferencing, and high-definition TV. It is suggested that a high-quality ET thin-film could be coupled directly with a CCD chip to perform real-time image subtraction between two simultaneous scenes or subsequent frames. The advantages of the ET-based technique over the incoherent image-subtraction technique based on two liquid-crystal light valves include absence of coherent noise, high resolution, high space-bandwidth product, high speed, and cost effectiveness.

  14. Myeloid-Specific Blockade of Notch Signaling by RBP-J Knockout Attenuates Spinal Cord Injury Accompanied by Compromised Inflammation Response in Mice.

    PubMed

    Chen, Bei-Yu; Zheng, Min-Hua; Chen, Yan; Du, Yan-Ling; Sun, Xiao-Long; Zhang, Xing; Duan, Li; Gao, Fang; Liang, Liang; Qin, Hong-Yan; Luo, Zhuo-Jing; Han, Hua

    2015-12-01

    The outcome of spinal cord injury (SCI) is determined by both neural cell-intrinsic survival pathways and tissue microenvironment-derived signals. Macrophages dominating the inflammatory responses in SCI possess both destructive and reparative potentials, according to their activation status. Notch signaling is involved in both cell survival and macrophage-mediated inflammation, but a comprehensive role of Notch signaling in SCI has been elusive. In this study, we compared the effects of general Notch blockade by a pharmaceutical γ-secretase inhibitor (GSI) and myeloid-specific Notch signal disruption by recombination signal binding protein Jκ (RBP-J) knockout on SCI. The administration of Notch signal inhibitor GSI resulted in worsened hind limb locomotion and exacerbated inflammation. However, mice lacking RBP-J, the critical transcription factor mediating signals from all four mammalian Notch receptors, in myeloid lineage displayed promoted functional recovery, attenuated glial scar formation, improved neuronal survival and axon regrowth, and mitigated inflammatory response after SCI. These benefits were accompanied by enhanced AKT activation in the lesion area after SCI. These findings demonstrate that abrogating Notch signal in myeloid cells ameliorates inflammation response post-SCI and promotes functional recovery, but general pharmaceutical Notch interception has opposite effects. Therefore, clinical intervention of Notch signaling in SCI needs to pinpoint myeloid lineage to avoid the counteractive effects of global inhibition.

  15. Event specific simultaneous estimates of loss, diffusion, and acceleration for MeV electrons

    NASA Astrophysics Data System (ADS)

    Schiller, Q.; Li, X.; Tu, W.; Ali, A.; Godinez, H. C.

    2015-12-01

    The most significant unknown in outer radiation belt electron dynamics is the relative contribution of loss, transport, and acceleration processes inside the inner magnetosphere. Detangling each individual process is critical to improve the understanding of radiation belt dynamics, but determining any single component is difficult due to sparse measurements of a large observation space. However, in the current era, an unprecedented number of spacecraft are taking measurements, and they are sampling different regions of the inner magnetosphere. With today's observations, system dynamics can begin to be unraveled. In this work, we focus on in-situ measurements during a single outer belt enhancement event, which occurred on January 13-14, 2013. We use Van Allen Probe measurements of ULF wave activity to determine radial transport rates. We use Colorado Student Space Weather Experiment observations to model electron lifetimes from atmospheric precipitation caused by pitch-angle diffusion. To estimate the source rate, we use a data assimilative model. The Kalman filter method we use estimates the full radial phase space density profile, as well as the amplitude, location, and radial extent of a Guassian-shaped source region. The estimates are made by minimizing the residuals between a simple 1D radial diffusion model and Van Allen Probe phase space density observations for mu=750 MeV/G and K=0.11 G^(1/2)R_E. The model also quantifies electrons lost to the outer boundary, providing direct comparison between losses to the inner and outer boundaries. This work produces simultaneous, quantitative estimates of loss, transport, and acceleration mechanisms and the relative contribution from each.

  16. An Interoperability Platform Enabling Reuse of Electronic Health Records for Signal Verification Studies

    PubMed Central

    Yuksel, Mustafa; Gonul, Suat; Laleci Erturkmen, Gokce Banu; Sinaci, Ali Anil; Invernizzi, Paolo; Facchinetti, Sara; Migliavacca, Andrea; Bergvall, Tomas; Depraetere, Kristof; De Roo, Jos

    2016-01-01

    Depending mostly on voluntarily sent spontaneous reports, pharmacovigilance studies are hampered by low quantity and quality of patient data. Our objective is to improve postmarket safety studies by enabling safety analysts to seamlessly access a wide range of EHR sources for collecting deidentified medical data sets of selected patient populations and tracing the reported incidents back to original EHRs. We have developed an ontological framework where EHR sources and target clinical research systems can continue using their own local data models, interfaces, and terminology systems, while structural interoperability and Semantic Interoperability are handled through rule-based reasoning on formal representations of different models and terminology systems maintained in the SALUS Semantic Resource Set. SALUS Common Information Model at the core of this set acts as the common mediator. We demonstrate the capabilities of our framework through one of the SALUS safety analysis tools, namely, the Case Series Characterization Tool, which have been deployed on top of regional EHR Data Warehouse of the Lombardy Region containing about 1 billion records from 16 million patients and validated by several pharmacovigilance researchers with real-life cases. The results confirm significant improvements in signal detection and evaluation compared to traditional methods with the missing background information. PMID:27123451

  17. An Interoperability Platform Enabling Reuse of Electronic Health Records for Signal Verification Studies.

    PubMed

    Yuksel, Mustafa; Gonul, Suat; Laleci Erturkmen, Gokce Banu; Sinaci, Ali Anil; Invernizzi, Paolo; Facchinetti, Sara; Migliavacca, Andrea; Bergvall, Tomas; Depraetere, Kristof; De Roo, Jos

    2016-01-01

    Depending mostly on voluntarily sent spontaneous reports, pharmacovigilance studies are hampered by low quantity and quality of patient data. Our objective is to improve postmarket safety studies by enabling safety analysts to seamlessly access a wide range of EHR sources for collecting deidentified medical data sets of selected patient populations and tracing the reported incidents back to original EHRs. We have developed an ontological framework where EHR sources and target clinical research systems can continue using their own local data models, interfaces, and terminology systems, while structural interoperability and Semantic Interoperability are handled through rule-based reasoning on formal representations of different models and terminology systems maintained in the SALUS Semantic Resource Set. SALUS Common Information Model at the core of this set acts as the common mediator. We demonstrate the capabilities of our framework through one of the SALUS safety analysis tools, namely, the Case Series Characterization Tool, which have been deployed on top of regional EHR Data Warehouse of the Lombardy Region containing about 1 billion records from 16 million patients and validated by several pharmacovigilance researchers with real-life cases. The results confirm significant improvements in signal detection and evaluation compared to traditional methods with the missing background information. PMID:27123451

  18. Synthesis of specific nanoparticles for targeting tumor angiogenesis using electron-beam irradiation

    NASA Astrophysics Data System (ADS)

    Deshayes, Stéphanie; Maurizot, Victor; Clochard, Marie-Claude; Berthelot, Thomas; Baudin, Cécile; Déléris, Gérard

    2010-03-01

    Angiogenesis plays a critical role in both growth and metastasis of tumors. Vascular endothelial growth factor (VEGF) is an endogenous mediator of tumor angiogenesis. Blocking associations of the VEGF with its corresponding receptors (KDR) have become critical for anti-tumor therapy. A cyclo-peptide (CBO-P11), derived from VEGF, able to inhibit the interaction between the growth factor and its receptor, was synthesized in our laboratory to provide a target for angiogenesis. We have prepared biocompatible poly(vinylidene fluoride) (PVDF) nanoparticles in order to obtain long blood circulating systems. Electron-beam (EB) irradiation was used to activate the PVDF nanoparticles. From electron paramagnetic resonance (EPR) measurements, we studied the radical stability in order to optimize the radio-grafting of acrylic acid (AA). Further functionalization of PVDF-g-PAA nanoparticles with the cyclo-peptide via a spacer arm was also possible by performing coupling reactions. High resolution magic angle spinning nuclear magnetic resonance (HRMAS NMR) and MALDI mass spectrometry allowed us to follow each chemical step of this peptide immobilization. We designed a new nanodevice suggesting a great potential for targeting angiogenesis. 7727-21-1

  19. Effects of plasma density irregularities on the pitch angle scattering of radiation belt electrons by signals from ground based VLF transmitters

    NASA Astrophysics Data System (ADS)

    Bell, T. F.; Inan, U. S.; Piddyachiy, D.; Kulkarni, P.; Parrot, M.

    2008-10-01

    Recent DEMETER spacecraft observations show that VLF signals from the NPM transmitter in Hawaii often strongly excite quasi-electrostatic whistler mode waves as the NPM signals propagate upward through plasma density irregularities. As a result of the NPM wave energy loss to the quasi-electrostatic waves, the transmitter signals will arrive at the radiation belts with less intensity than predicted by present models of VLF wave propagation and will produce less pitch angle scattering of energetic electrons than presently believed. This type of wave energy loss may be partially responsible for the pervasive wave intensity deficit for VLF transmitter signals in the plasmasphere recently noted by Starks et al. (2008).

  20. Terahertz signal detection in a short gate length field-effect transistor with a two-dimensional electron gas

    SciTech Connect

    Vostokov, N. V. Shashkin, V. I.

    2015-11-28

    We consider the problem of non-resonant detection of terahertz signals in a short gate length field-effect transistor having a two-dimensional electron channel with zero external bias between the source and the drain. The channel resistance, gate-channel capacitance, and quadratic nonlinearity parameter of the transistor during detection as a function of the gate bias voltage are studied. Characteristics of detection of the transistor connected in an antenna with real impedance are analyzed. The consideration is based on both a simple one-dimensional model of the transistor and allowance for the two-dimensional distribution of the electric field in the transistor structure. The results given by the different models are discussed.

  1. Small-signal modeling with direct parameter extraction for impact ionization effect in high-electron-mobility transistors

    SciTech Connect

    Guan, He; Lv, Hongliang; Guo, Hui Zhang, Yuming

    2015-11-21

    Impact ionization affects the radio-frequency (RF) behavior of high-electron-mobility transistors (HEMTs), which have narrow-bandgap semiconductor channels, and this necessitates complex parameter extraction procedures for HEMT modeling. In this paper, an enhanced small-signal equivalent circuit model is developed to investigate the impact ionization, and an improved method is presented in detail for direct extraction of intrinsic parameters using two-step measurements in low-frequency and high-frequency regimes. The practicability of the enhanced model and the proposed direct parameter extraction method are verified by comparing the simulated S-parameters with published experimental data from an InAs/AlSb HEMT operating over a wide frequency range. The results demonstrate that the enhanced model with optimal intrinsic parameter values that were obtained by the direct extraction approach can effectively characterize the effects of impact ionization on the RF performance of HEMTs.

  2. Evaluation of COTS SiGe, SOI, and Mixed Signal Electronic Parts for Extreme Temperature Use in NASA Missions

    NASA Technical Reports Server (NTRS)

    Patterson, Richard L.; Hammoud, Ahmad

    2010-01-01

    The NASA Electronic Parts and Packaging (NEPP) Program sponsors a task at the NASA Glenn Research Center titled "Reliability of SiGe, SOI, and Advanced Mixed Signal Devices for Cryogenic Space Missions." In this task COTS parts and flight-like are evaluated by determining their performance under extreme temperatures and thermal cycling. The results from the evaluations are published on the NEPP website and at professional conferences in order to disseminate information to mission planners and system designers. This presentation discusses the task and the 2010 highlights and technical results. Topics include extreme temperature operation of SiGe and SOI devices, all-silicon oscillators, a floating gate voltage reference, a MEMS oscillator, extreme temperature resistors and capacitors, and a high temperature silicon operational amplifier.

  3. Highly specific SNP detection using 2D graphene electronics and DNA strand displacement

    PubMed Central

    Hwang, Michael T.; Landon, Preston B.; Lee, Joon; Choi, Duyoung; Mo, Alexander H.; Glinsky, Gennadi; Lal, Ratnesh

    2016-01-01

    Single-nucleotide polymorphisms (SNPs) in a gene sequence are markers for a variety of human diseases. Detection of SNPs with high specificity and sensitivity is essential for effective practical implementation of personalized medicine. Current DNA sequencing, including SNP detection, primarily uses enzyme-based methods or fluorophore-labeled assays that are time-consuming, need laboratory-scale settings, and are expensive. Previously reported electrical charge-based SNP detectors have insufficient specificity and accuracy, limiting their effectiveness. Here, we demonstrate the use of a DNA strand displacement-based probe on a graphene field effect transistor (FET) for high-specificity, single-nucleotide mismatch detection. The single mismatch was detected by measuring strand displacement-induced resistance (and hence current) change and Dirac point shift in a graphene FET. SNP detection in large double-helix DNA strands (e.g., 47 nt) minimize false-positive results. Our electrical sensor-based SNP detection technology, without labeling and without apparent cross-hybridization artifacts, would allow fast, sensitive, and portable SNP detection with single-nucleotide resolution. The technology will have a wide range of applications in digital and implantable biosensors and high-throughput DNA genotyping, with transformative implications for personalized medicine. PMID:27298347

  4. Highly specific SNP detection using 2D graphene electronics and DNA strand displacement.

    PubMed

    Hwang, Michael T; Landon, Preston B; Lee, Joon; Choi, Duyoung; Mo, Alexander H; Glinsky, Gennadi; Lal, Ratnesh

    2016-06-28

    Single-nucleotide polymorphisms (SNPs) in a gene sequence are markers for a variety of human diseases. Detection of SNPs with high specificity and sensitivity is essential for effective practical implementation of personalized medicine. Current DNA sequencing, including SNP detection, primarily uses enzyme-based methods or fluorophore-labeled assays that are time-consuming, need laboratory-scale settings, and are expensive. Previously reported electrical charge-based SNP detectors have insufficient specificity and accuracy, limiting their effectiveness. Here, we demonstrate the use of a DNA strand displacement-based probe on a graphene field effect transistor (FET) for high-specificity, single-nucleotide mismatch detection. The single mismatch was detected by measuring strand displacement-induced resistance (and hence current) change and Dirac point shift in a graphene FET. SNP detection in large double-helix DNA strands (e.g., 47 nt) minimize false-positive results. Our electrical sensor-based SNP detection technology, without labeling and without apparent cross-hybridization artifacts, would allow fast, sensitive, and portable SNP detection with single-nucleotide resolution. The technology will have a wide range of applications in digital and implantable biosensors and high-throughput DNA genotyping, with transformative implications for personalized medicine.

  5. Highly specific SNP detection using 2D graphene electronics and DNA strand displacement.

    PubMed

    Hwang, Michael T; Landon, Preston B; Lee, Joon; Choi, Duyoung; Mo, Alexander H; Glinsky, Gennadi; Lal, Ratnesh

    2016-06-28

    Single-nucleotide polymorphisms (SNPs) in a gene sequence are markers for a variety of human diseases. Detection of SNPs with high specificity and sensitivity is essential for effective practical implementation of personalized medicine. Current DNA sequencing, including SNP detection, primarily uses enzyme-based methods or fluorophore-labeled assays that are time-consuming, need laboratory-scale settings, and are expensive. Previously reported electrical charge-based SNP detectors have insufficient specificity and accuracy, limiting their effectiveness. Here, we demonstrate the use of a DNA strand displacement-based probe on a graphene field effect transistor (FET) for high-specificity, single-nucleotide mismatch detection. The single mismatch was detected by measuring strand displacement-induced resistance (and hence current) change and Dirac point shift in a graphene FET. SNP detection in large double-helix DNA strands (e.g., 47 nt) minimize false-positive results. Our electrical sensor-based SNP detection technology, without labeling and without apparent cross-hybridization artifacts, would allow fast, sensitive, and portable SNP detection with single-nucleotide resolution. The technology will have a wide range of applications in digital and implantable biosensors and high-throughput DNA genotyping, with transformative implications for personalized medicine. PMID:27298347

  6. Disseminating context-specific access to online knowledge resources within electronic health record systems.

    PubMed

    Del Fiol, Guilherme; Curtis, Clayton; Cimino, James J; Iskander, Andrew; Kalluri, Aditya S D; Jing, Xia; Hulse, Nathan C; Long, Jie; Overby, Casey L; Schardt, Connie; Douglas, David M

    2013-01-01

    Clinicians' patient care information needs are frequent and largely unmet. Online knowledge resources are available that can help clinicians meet these information needs. Yet, significant barriers limit the use of these resources within the clinical workflow. Infobuttons are clinical decision support tools that use the clinical context (e.g., institution, user, patient) within electronic health record (EHR) systems to anticipate clinicians' questions and provide automated links to relevant information in knowledge resources. This paper describes OpenInfobutton (www.openinfobutton.org): a standards-based, open source Web service that was designed to disseminate infobutton capabilities in multiple EHR systems and healthcare organizations. OpenInfobutton has been successfully integrated with 38 knowledge resources at 5 large healthcare organizations in the United States. We describe the OpenInfobutton architecture, knowledge resource integration, and experiences at five large healthcare organizations.

  7. State-specific tunneling lifetimes from classical trajectories: H-atom dissociation in electronically excited pyrrole

    NASA Astrophysics Data System (ADS)

    Xie, Weiwei; Domcke, Wolfgang; Farantos, Stavros C.; Grebenshchikov, Sergy Yu.

    2016-03-01

    A trajectory method of calculating tunneling probabilities from phase integrals along straight line tunneling paths, originally suggested by Makri and Miller [J. Chem. Phys. 91, 4026 (1989)] and recently implemented by Truhlar and co-workers [Chem. Sci. 5, 2091 (2014)], is tested for one- and two-dimensional ab initio based potentials describing hydrogen dissociation in the 1B1 excited electronic state of pyrrole. The primary observables are the tunneling rates in a progression of bending vibrational states lying below the dissociation barrier and their isotope dependences. Several initial ensembles of classical trajectories have been considered, corresponding to the quasiclassical and the quantum mechanical samplings of the initial conditions. It is found that the sampling based on the fixed energy Wigner density gives the best agreement with the quantum mechanical dissociation rates.

  8. Disseminating Context-Specific Access to Online Knowledge Resources within Electronic Health Record Systems

    PubMed Central

    Fiol, Guilherme Del; Curtis, Clayton; Cimino, James J.; Iskander, Andrew; Kalluri, Aditya S.D.; Jing, Xia; Hulse, Nathan C.; Long, Jie; Overby, Casey L.; Schardt, Connie; Douglas, David M.

    2013-01-01

    Clinicians’ patient care information needs are frequent and largely unmet. Online knowledge resources are available that can help clinicians meet these information needs. Yet, significant barriers limit the use of these resources within the clinical workflow. Infobuttons are clinical decision support tools that use the clinical context (e.g., institution, user, patient) within electronic health record (EHR) systems to anticipate clinicians’ questions and provide automated links to relevant information in knowledge resources. This paper describes OpenInfobutton (www.openinfobutton.org): a standards-based, open source Web service that was designed to disseminate infobutton capabilities in multiple EHR systems and healthcare organizations. OpenInfobutton has been successfully integrated with 38 knowledge resources at 5 large healthcare organizations in the United States. We describe the OpenInfobutton architecture, knowledge resource integration, and experiences at five large healthcare organizations. PMID:23920641

  9. In vitro selection of state-specific peptide modulators of G protein signaling using mRNA display.

    PubMed

    Ja, William W; Roberts, Richard W

    2004-07-20

    The G protein regulatory (GPR) motif is a approximately 20-residue conserved domain that acts as a guanine dissociation inhibitor (GDI) for G(i/o)(alpha) subunits. Here, we describe the isolation of peptides derived from a GPR consensus sequence using mRNA display selection libraries. Biotinylated G(i)(alpha)(1), modified at either the N or C terminus, serves as a high-affinity binding target for mRNA-displayed GPR peptides. In vitro selection using mRNA display libraries based on the C terminus of the GPR motif revealed novel peptide sequences with conserved residues. Surprisingly, selected peptides contain mutations to a highly conserved Arg in the GPR motif, previously shown to be crucial for binding and inhibition activities. The dominant peptide from the selection, R6A, and a minimal 9-mer peptide, R6A-1, do not contain Arg residues yet retain high affinity (K(D) = 60 and 200 nM, respectively) and specificity for the GDP-bound state of G(i)(alpha)(1), as measured by surface plasmon resonance. The selected peptides also maintain GDI activity for G(i)(alpha)(1), inhibiting both the exchange of GDP in GTPgammaS binding assays and the AlF(4)(-)-stimulated enhancement of intrinsic tryptophan fluorescence. The kinetics of GDI activity, however, are different for the selected peptides and demonstrate biphasic kinetics, suggesting a complex mechanism for inhibition. Like the GPR motif, the R6A and R6A-1 peptides compete with G(betagamma) subunits for binding to G(i)(alpha)(1), suggesting their use as activators of G(betagamma) signaling. PMID:15248784

  10. How dangerous are phthalate plasticizers? Integrated approach to toxicity based on metabolism, electron transfer, reactive oxygen species and cell signaling.

    PubMed

    Kovacic, Peter

    2010-04-01

    Phthalate plasticizers are the most abundant man-made pollutants that have recently received wide-spread attention. There is uncertainty concerning the toxicity to humans. During the debate, scant attention has been paid to adverse effects at the molecular level which is the focus of this article. Most metabolic reports are concerned only with ester hydrolysis. In addition to that aspect, an important study deals with formation of catechol carboxylic acids which have the potential to redox cycle with the o-quinone counterparts. This electron transfer (ET) process is capable of generating reactive oxygen species (ROS) which are well known toxic agents at elevated levels. Substantial numbers of investigations find the presence of ROS leading to oxidative stress (OS) in living systems containing phthalates. Insults occur to various organs, including the reproductive system, pulmonary, central nervous system, immune system and liver. Toxic reactions are also reported involving inflammation, mitochondria and carcinogenicity. Generally, OS evidently plays a role. Of relevance are prior reviews which document extensive evidence for association of ET-ROS-OS with organ toxicity, and other deleterious reactions. In addition, cell signaling has been related to the physiological effects of phthalates. Various signaling processes participate together with involvement of ROS and association with biological effects. Suggestions for future work are offered.

  11. Neuron class-specific requirements for Fragile X Mental Retardation Protein in critical period development of calcium signaling in learning and memory circuitry.

    PubMed

    Doll, Caleb A; Broadie, Kendal

    2016-05-01

    Neural circuit optimization occurs through sensory activity-dependent mechanisms that refine synaptic connectivity and information processing during early-use developmental critical periods. Fragile X Mental Retardation Protein (FMRP), the gene product lost in Fragile X syndrome (FXS), acts as an activity sensor during critical period development, both as an RNA-binding translation regulator and channel-binding excitability regulator. Here, we employ a Drosophila FXS disease model to assay calcium signaling dynamics with a targeted transgenic GCaMP reporter during critical period development of the mushroom body (MB) learning/memory circuit. We find FMRP regulates depolarization-induced calcium signaling in a neuron-specific manner within this circuit, suppressing activity-dependent calcium transients in excitatory cholinergic MB input projection neurons and enhancing calcium signals in inhibitory GABAergic MB output neurons. Both changes are restricted to the developmental critical period and rectified at maturity. Importantly, conditional genetic (dfmr1) rescue of null mutants during the critical period corrects calcium signaling defects in both neuron classes, indicating a temporally restricted FMRP requirement. Likewise, conditional dfmr1 knockdown (RNAi) during the critical period replicates constitutive null mutant defects in both neuron classes, confirming cell-autonomous requirements for FMRP in developmental regulation of calcium signaling dynamics. Optogenetic stimulation during the critical period enhances depolarization-induced calcium signaling in both neuron classes, but this developmental change is eliminated in dfmr1 null mutants, indicating the activity-dependent regulation requires FMRP. These results show FMRP shapes neuron class-specific calcium signaling in excitatory vs. inhibitory neurons in developing learning/memory circuitry, and that FMRP mediates activity-dependent regulation of calcium signaling specifically during the early

  12. Neuron class-specific requirements for Fragile X Mental Retardation Protein in critical period development of calcium signaling in learning and memory circuitry.

    PubMed

    Doll, Caleb A; Broadie, Kendal

    2016-05-01

    Neural circuit optimization occurs through sensory activity-dependent mechanisms that refine synaptic connectivity and information processing during early-use developmental critical periods. Fragile X Mental Retardation Protein (FMRP), the gene product lost in Fragile X syndrome (FXS), acts as an activity sensor during critical period development, both as an RNA-binding translation regulator and channel-binding excitability regulator. Here, we employ a Drosophila FXS disease model to assay calcium signaling dynamics with a targeted transgenic GCaMP reporter during critical period development of the mushroom body (MB) learning/memory circuit. We find FMRP regulates depolarization-induced calcium signaling in a neuron-specific manner within this circuit, suppressing activity-dependent calcium transients in excitatory cholinergic MB input projection neurons and enhancing calcium signals in inhibitory GABAergic MB output neurons. Both changes are restricted to the developmental critical period and rectified at maturity. Importantly, conditional genetic (dfmr1) rescue of null mutants during the critical period corrects calcium signaling defects in both neuron classes, indicating a temporally restricted FMRP requirement. Likewise, conditional dfmr1 knockdown (RNAi) during the critical period replicates constitutive null mutant defects in both neuron classes, confirming cell-autonomous requirements for FMRP in developmental regulation of calcium signaling dynamics. Optogenetic stimulation during the critical period enhances depolarization-induced calcium signaling in both neuron classes, but this developmental change is eliminated in dfmr1 null mutants, indicating the activity-dependent regulation requires FMRP. These results show FMRP shapes neuron class-specific calcium signaling in excitatory vs. inhibitory neurons in developing learning/memory circuitry, and that FMRP mediates activity-dependent regulation of calcium signaling specifically during the early

  13. Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

    NASA Astrophysics Data System (ADS)

    Suyanto, Hery; Pardede, Marincan; Hedwig, Rinda; Marpaung, Alion Mangasi; Ramli, Muliadi; Lie, Tjung Jie; Abdulmadjid, Syahrun Nur; Kurniawan, Koo Hendrik; Tjia, May On; Kagawa, Kiichiro

    2016-08-01

    A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns) and picosecond (ps) lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE) mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS) using He ambient gas.

  14. Fault handling schemes in electronic systems with specific application to radiation tolerance and VLSI design

    NASA Technical Reports Server (NTRS)

    Attia, John Okyere

    1993-01-01

    Naturally occurring space radiation particles can produce transient and permanent changes in the electrical properties of electronic devices and systems. In this work, the transient radiation effects on DRAM and CMOS SRAM were considered. In addition, the effect of total ionizing dose radiation of the switching times of CMOS logic gates were investigated. Effects of transient radiation on the column and cell of MOS dynamic memory cell was simulated using SPICE. It was found that the critical charge of the bitline was higher than that of the cell. In addition, the critical charge of the combined cell-bitline was found to be dependent on the gate voltage of the access transistor. In addition, the effect of total ionizing dose radiation on the switching times of CMOS logic gate was obtained. The results of this work indicate that, the rise time of CMOS logic gates increases, while the fall time decreases with an increase in total ionizing dose radiation. Also, by increasing the size of the P-channel transistor with respect to that of the N-channel transistor, the propagation delay of CMOS logic gate can be made to decrease with, or be independent of an increase in total ionizing dose radiation. Furthermore, a method was developed for replacing polysilicon feedback resistance of SRAMs with a switched capacitor network. A switched capacitor SRAM was implemented using MOS Technology. The critical change of the switched capacitor SRAM has a very large critical charge. The results of this work indicate that switched capacitor SRAM is a viable alternative to SRAM with polysilicon feedback resistance.

  15. Highly specific fluorescence detection of T4 polynucleotide kinase activity via photo-induced electron transfer.

    PubMed

    Tao, Mangjuan; Shi, Zhilu; Cheng, Rui; Zhang, Jing; Li, Baoxin; Jin, Yan

    2015-09-15

    Sensitive and reliable study of the activity of polynucleotide kinase (PNK) and its potential inhibitors is of great importance for biochemical interaction related to DNA phosphorylation as well as development of kinase-targeted drug discovery. To achieve facile and reliable detection of PNK activity, we report here a novel fluorescence method for PNK assay based on a combination of exonuclease cleavage reaction and photo-induced electron transfer (PIET) by using T4 PNK as a model target. The fluorescence of 3'-carboxyfluorescein-labeled DNA probe (FDNA) is effectively quenched by deoxyguanosines at the 5' end of its complementary DNA (cDNA) due to an effective PIET between deoxyguanosines and fluorophore. Whereas FDNA/cDNA hybrid is phosphorylated by PNK and then immediately cleaved by lambda exonuclease (λ exo), fluorescence is greatly restored due to the break of PIET. This homogeneous PNK activity assay does not require a complex design by taking advantage of the quenching ability of deoxyguanosines, making the proposed strategy facile and cost-effective. The activity of PNK can be sensitively detected in the range of 0.005 to 10 U mL(-1) with a detection limit of 2.1×10(-3) U mL(-1). Research on inhibition efficiency of different inhibitors demonstrated that it can be explored to evaluate inhibition capacity of inhibitors. The application for detection of PNK activity in complex matrix achieved satisfactory results. Therefore, this PIET strategy opens a promising avenue for studying T4 PNK activity as well as evaluating PNK inhibitors, which is of great importance for discovering kinase-targeted drugs. PMID:26050629

  16. Control of MAPK signaling specificity by a conserved residue in the MEK-binding domain of the yeast scaffold protein Ste5.

    PubMed

    Schwartz, Monica A; Madhani, Hiten D

    2006-06-01

    The yeast kinase scaffold Ste5 has been proposed to prevent unwanted cross-talk between the pheromone response pathway and other MAPK cascades. Protein fusion experiments have demonstrated that covalently tethering signaling components to each other or to Ste5 can determine the outcome of signaling. However, these do not fully test the role of scaffolds in signaling specificity, since fusing components precludes differential dissociation of subpopulations. We performed a targeted genetic screen on STE5 and repeatedly identified recessive mutations in a conserved residue, E756, in the Ste7/MEK-binding domain that caused erroneous activation of the filamentation MAPK pathway by pheromone signaling. Mutant cells exhibited a shift in the MAPK activation pattern such that the filamentation MAPK Kss1 was predominately activated in response to pheromone. Velocity sedimentation studies showed that the mutant scaffold was defective in binding to a phosphorylated subpopulation of Ste7. Our data suggest that increased dissociation of activated Ste7 kinase from the mutant scaffold may cause the observed shift in MAPK activation from Fus3 to Kss1 and the resulting loss of specificity. Cross-talk in ste5-E756G cells was due to both increased activation of Kss1 and reduced Fus3-dependent degradation of the filamentation pathway transcription factor Tec1. These studies demonstrate a role for an endogenous scaffold in signaling specificity. PMID:16463042

  17. A facile, sensitive, and highly specific trinitrophenol assay based on target-induced synergetic effects of acid induction and electron transfer towards DNA-templated copper nanoclusters.

    PubMed

    Li, Haiyin; Chang, Jiafu; Hou, Ting; Ge, Lei; Li, Feng

    2016-11-01

    Reliable, selective and sensitive approaches for trinitrophenol (TNP) detection are highly desirable with respect to national security and environmental protection. Herein, a simple and novel fluorescent strategy for highly sensitive and specific TNP assay has been successfully developed, which is based on the quenching of the fluorescent poly(thymine)-templated copper nanoclusters (DNA-CuNCs), through the synergetic effects of acid induction and electron transfer. Upon the addition of TNP, donor-acceptor complexes between the electron-deficient nitro-groups in TNP and the electron-donating DNA templates are formed, resulting in the close proximity between TNP and CuNCs. Moreover, the acidity of TNP contributes to the pH decrease of the system. These factors combine to dramatically quench the fluorescence of DNA-CuNCs, providing a "signal-off" strategy for TNP sensing. The as-proposed strategy demonstrates high sensitivity for TNP assay, and a detection limit of 0.03μM is obtained, which is lower than those reported by using organic fluorescent materials. More significantly, this approach shows outstanding selectivity over a number of TNP analogues, such as 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT), 2,4-dinitrophenol (DNP), 3-nitrophenol (NP), nitrobenzene (NB), phenol (BP), and toluene (BT). Compared with previous studies, this method does not need complex DNA sequence design, fluorescent dye labeling, or sophisticated organic reactions, rendering the strategy with additional advantages of simplicity and cost-effectiveness. In addition, the as-proposed strategy has been adopted for the detection of TNP in natural water samples, indicating its great potential to be applied in the fields of public safety and environmental monitoring. PMID:27591641

  18. Parameter-specific electronic measurement and analysis of sources of variation using ring oscillators

    NASA Astrophysics Data System (ADS)

    Wang, Lynn T.-N.; Pang, Liang-Teck; Neureuther, Andrew R.; Nikolić, Borivoje

    2009-03-01

    Parameter-specific and simulation-calibrated ring oscillator (RO) inverter layouts are described for identifying and quantitatively modeling sources of circuit performance variation from source/drain stress, shallow trench isolation (STI) stress, lithography, etch, and misalignment. This paper extends the RO approach by adding physical modeling/simulation of the sources of variability to tune the layouts of monitors for enhanced sensitivity and selectivity. Poly and diffusion layout choices have been guided by fast-CAD pattern matching. The accuracy of the fast-CAD estimate from the Pattern Matcher for these lithography issues is corroborated by simulations in Mentor Graphics Calibre. Generic conceptual results are given based on the experience from preparing of proprietary layouts that pass DRC check for a 45 nm test chip with ST Micro. Typical improvements in sensitivity of 2 fold are possible with layouts for lithography focus. A layout monitor for poly to diffusion misalignment based on programmable off-sets shows a 0.8% change in RO frequency per 1nm poly to diffusion off-set. Layouts are also described for characterizing stress effects associated with diffusion area size, asymmetry, vertical spacing, and multiple gate lengths.

  19. Hog1 mitogen-activated protein kinase (MAPK) interrupts signal transduction between the Kss1 MAPK and the Tec1 transcription factor to maintain pathway specificity.

    PubMed

    Shock, Teresa R; Thompson, James; Yates, John R; Madhani, Hiten D

    2009-04-01

    In Saccharomyces cerevisiae, the mating, filamentous growth (FG), and high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) signaling pathways share components and yet mediate distinct responses to different extracellular signals. Cross talk is suppressed between the mating and FG pathways because mating signaling induces the destruction of the FG transcription factor Tec1. We show here that HOG pathway activation results in phosphorylation of the FG MAPK, Kss1, and the MAPKK, Ste7. However, FG transcription is not activated because HOG signaling prevents the activation of Tec1. In contrast to the mating pathway, we find that the mechanism involves the inhibition of DNA binding by Tec1 rather than its destruction. We also find that nuclear accumulation of Tec1 is not affected by HOG signaling. Inhibition by Hog1 is apparently indirect since it does not require any of the consensus S/TP MAPK phosphorylation sites on Tec1, its DNA-binding partner Ste12, or the associated regulators Dig1 or Dig2. It also does not require the consensus MAPK sites of the Ste11 activator Ste50, in contrast to a recent proposal for a role for negative feedback in specificity. Our results demonstrate that HOG signaling interrupts the FG pathway signal transduction between the phosphorylation of Kss1 and the activation of DNA binding by Tec1. PMID:19218425

  20. Trans-ethnic fine-mapping of lipid loci identifies population-specific signals and allelic heterogeneity that increases the trait variance explained.

    PubMed

    Wu, Ying; Waite, Lindsay L; Jackson, Anne U; Sheu, Wayne H-H; Buyske, Steven; Absher, Devin; Arnett, Donna K; Boerwinkle, Eric; Bonnycastle, Lori L; Carty, Cara L; Cheng, Iona; Cochran, Barbara; Croteau-Chonka, Damien C; Dumitrescu, Logan; Eaton, Charles B; Franceschini, Nora; Guo, Xiuqing; Henderson, Brian E; Hindorff, Lucia A; Kim, Eric; Kinnunen, Leena; Komulainen, Pirjo; Lee, Wen-Jane; Le Marchand, Loic; Lin, Yi; Lindström, Jaana; Lingaas-Holmen, Oddgeir; Mitchell, Sabrina L; Narisu, Narisu; Robinson, Jennifer G; Schumacher, Fred; Stančáková, Alena; Sundvall, Jouko; Sung, Yun-Ju; Swift, Amy J; Wang, Wen-Chang; Wilkens, Lynne; Wilsgaard, Tom; Young, Alicia M; Adair, Linda S; Ballantyne, Christie M; Bůžková, Petra; Chakravarti, Aravinda; Collins, Francis S; Duggan, David; Feranil, Alan B; Ho, Low-Tone; Hung, Yi-Jen; Hunt, Steven C; Hveem, Kristian; Juang, Jyh-Ming J; Kesäniemi, Antero Y; Kuusisto, Johanna; Laakso, Markku; Lakka, Timo A; Lee, I-Te; Leppert, Mark F; Matise, Tara C; Moilanen, Leena; Njølstad, Inger; Peters, Ulrike; Quertermous, Thomas; Rauramaa, Rainer; Rotter, Jerome I; Saramies, Jouko; Tuomilehto, Jaakko; Uusitupa, Matti; Wang, Tzung-Dau; Boehnke, Michael; Haiman, Christopher A; Chen, Yii-Der I; Kooperberg, Charles; Assimes, Themistocles L; Crawford, Dana C; Hsiung, Chao A; North, Kari E; Mohlke, Karen L

    2013-03-01

    Genome-wide association studies (GWAS) have identified ~100 loci associated with blood lipid levels, but much of the trait heritability remains unexplained, and at most loci the identities of the trait-influencing variants remain unknown. We conducted a trans-ethnic fine-mapping study at 18, 22, and 18 GWAS loci on the Metabochip for their association with triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), respectively, in individuals of African American (n = 6,832), East Asian (n = 9,449), and European (n = 10,829) ancestry. We aimed to identify the variants with strongest association at each locus, identify additional and population-specific signals, refine association signals, and assess the relative significance of previously described functional variants. Among the 58 loci, 33 exhibited evidence of association at P<1 × 10(-4) in at least one ancestry group. Sequential conditional analyses revealed that ten, nine, and four loci in African Americans, Europeans, and East Asians, respectively, exhibited two or more signals. At these loci, accounting for all signals led to a 1.3- to 1.8-fold increase in the explained phenotypic variance compared to the strongest signals. Distinct signals across ancestry groups were identified at PCSK9 and APOA5. Trans-ethnic analyses narrowed the signals to smaller sets of variants at GCKR, PPP1R3B, ABO, LCAT, and ABCA1. Of 27 variants reported previously to have functional effects, 74% exhibited the strongest association at the respective signal. In conclusion, trans-ethnic high-density genotyping and analysis confirm the presence of allelic heterogeneity, allow the identification of population-specific variants, and limit the number of candidate SNPs for functional studies. PMID:23555291

  1. Site-Specific Atomic and Electronic Structure Analysis of Epitaxial Silicon Oxynitride Thin Film on SiC(0001) by Photoelectron and Auger Electron Diffractions

    NASA Astrophysics Data System (ADS)

    Maejima, Naoyuki; Matsui, Fumihiko; Matsui, Hirosuke; Goto, Kentaro; Matsushita, Tomohiro; Tanaka, Satoru; Daimon, Hiroshi

    2014-04-01

    The film and interface structures of epitaxial silicon oxynitride (SiON) thin film grown on a SiC(0001) surface were investigated by photoelectron diffraction. Forward focusing peaks (FFPs) corresponding to the directions from the photoelectron emitter atom to the surrounding atoms appeared in the photoelectron intensity angular distribution (PIAD). By comparing N 1s PIAD with those of Si 2p and C 1s, we confirmed that the nitrogen atoms at SiON/SiC interface replace carbon atoms at stacking fault sites. Two kinds of oxygen atom sites exist in the previously proposed model [T. Shirasawa et al.: Phys. Rev. Lett. 98, 136105 (2007)]. FFP corresponding to Si-O-Si perpendicular bonds was observed in the O 1s PIAD, while diffraction rings were observed in the KLL Auger electron intensity angular distribution (AIAD), which were attributed to the diffraction patterns from outermost oxygen sites. Furthermore, O K-edge X-ray absorption spectra combined with AIAD were analyzed. An electronic structure specific to each oxygen atom site was successfully separated.

  2. SU-E-T-424: Dosimetric Verification of Modulated Electron Radiation Therapy Delivered Using An Electron Specific Multileaf Collimator for Treatment of Scalp Cases

    SciTech Connect

    Eldib, A; Jin, L; Martin, J; Li, J; Chibani, O; Galloway, T; Ma, C; Mora, G

    2014-06-01

    Purpose: Modulated electron radiotherapy (MERT) has the potential to achieve better treatment outcome for shallow tumors such as those of breast and scalp. In a separate study with scalp lesions, MERT was compared to volumetric modulated arc therapy. Our results showed a reduction in the dose reaching the brain with MERT. However dose calculation accuracy and delivery efficiency challenges remain. Thus in the current study we proceed to add more cases to demonstrate MERT beneficial outcome and its delivery accuracy using an electron specific multileaf collimator (eMLC). Methods: We have used the MCBEAM code for treatment head simulation and for generating phase space files to be used as radiation source input for our Monte Carlo based treatment planning system (MC TPS). MCPLAN code is used for calculation of patient specific dose deposition coefficient and for final MERT plan dose calculation. An in-house developed optimization code is used for the optimization process. MERT plans were generated for real patients and head and neck phantom. Film was used for dosimetric verification. The film was cut following the contour of the curved phantom surface and then sealed with black masking tape. In the measurement, the sealed film packet was sandwiched between two adjacent slabs of the head and neck phantom. The measured 2D dose distribution was then compared with calculations. Results: The eMLC allows effective treatment of scalps with multi-lesions spreading around the patient head, which was usually difficult to plan or very time consuming with conventional applicators. MERT continues to show better reduction in the brain dose. The dosimetric measurements showed slight discrepancy, which was attributed to the film setup. Conclusion: MERT can improve treatment plan quality for patients with scalp cancers. Our in-house MC TPS is capable of performing treatment planning and accurate dose calculation for MERT using the eMLC.

  3. Conformation-Specific Electronic and Vibrational Spectroscopy of DIBENZO-15-CROWN-5 Ether in a Supersonic Jet.

    NASA Astrophysics Data System (ADS)

    Buchanan, Evan G.; Rodrigo, Chirantha P.; James, William H. James, III; Newby, Josh J.; Zwier, Timothy S.

    2009-06-01

    Crown ethers are oxygen containing cyclic structures noted for their ability to preferentially bind substrates such as ions and water. Despite the high symmetry inherent to the chemical structure, crown ethers are remarkably flexible, adapting their conformation to the substrate to which they are bound. As such, it is valuable to study the conformational preferences of the isolated crown ethers in the absence of any substrate. Here, we present the electronic and infrared spectroscopy of jet-cooled, isolated dibenzo-15-crown-5 ether (DB15C). By incorporating two phenyl rings into the crown, we are afforded the opportunity to explore the ultraviolet spectroscopy of both groups and the coupling between them. One-color resonant two-photon ionization, laser induced fluorescence, UV-UV holeburning, and resonant ion-dip infrared spectroscopies are used to provide conformation-specific electronic and infrared spectra of the three conformers. Additionally, single vibronic level dispersed fluorescence spectra provide evidence for the existence of close lying S_2 states in the two major conformers, located about 527 cm^{-1} above their S_1 counterparts. Based on a comparison with benzo-15-crown-5 ether, we surmise that the local conformation of the ethoxy groups about the two phenyl rings are different. Electronic energy transfer appears to be slow between these phenyl rings on the timescale of the excited state fluorescence. Finally, DFT and MP2 calculations will be presented as a basis for tentative structural assignments and provide insight into the excitonic coupling of the two chromophores.

  4. Minimizing the magnetic field effect in MR-linac specific QA-tests: the use of electron dense materials.

    PubMed

    van Zijp, H M; van Asselen, B; Wolthaus, J W H; Kok, J M G; de Vries, J H W; Ishakoglu, K; Beld, E; Lagendijk, J J W; Raaymakers, B W

    2016-02-01

    To address the quality assurance (QA) of a MR-linac which is an MRI combined with a linear accelerator (linac), the traditional linac QA-tests need to be redesigned, since the presence of the static magnetic field in the MR-linac alters the electron trajectory. The latter causes the asymmetry in the dose kernel which is introduced by the magnetic field and hinders accurate geometrical QA-tests for the MR-linac. We introduced the use of electron dense materials (e.g. copper) to reduce the size of the dose kernel and thereby the magnetic field effect on the dose deposition. Two examples of QA-tests are presented in which the geometrical accuracy of the MR-linac was addressed; beam profile and star-shot measurements. The introduced setup was compared with a reference setup and both were tested on a conventional and the MR-linac. The results showed that the symmetry of the recorded beam profile was restored in presence of the copper material and that the isocenter size of the MR-linac can be determined accurately with the introduced star-shot setup. The use of electron dense materials is not limited to the presented QA-tests but has a broad application for beam-specific QA-tests in presence of a magnetic field. PMID:26758570

  5. Minimizing the magnetic field effect in MR-linac specific QA-tests: the use of electron dense materials

    NASA Astrophysics Data System (ADS)

    van Zijp, H. M.; van Asselen, B.; Wolthaus, J. W. H.; Kok, J. M. G.; de Vries, J. H. W.; Ishakoglu, K.; Beld, E.; Lagendijk, J. J. W.; Raaymakers, B. W.

    2016-02-01

    To address the quality assurance (QA) of a MR-linac which is an MRI combined with a linear accelerator (linac), the traditional linac QA-tests need to be redesigned, since the presence of the static magnetic field in the MR-linac alters the electron trajectory. The latter causes the asymmetry in the dose kernel which is introduced by the magnetic field and hinders accurate geometrical QA-tests for the MR-linac. We introduced the use of electron dense materials (e.g. copper) to reduce the size of the dose kernel and thereby the magnetic field effect on the dose deposition. Two examples of QA-tests are presented in which the geometrical accuracy of the MR-linac was addressed; beam profile and star-shot measurements. The introduced setup was compared with a reference setup and both were tested on a conventional and the MR-linac. The results showed that the symmetry of the recorded beam profile was restored in presence of the copper material and that the isocenter size of the MR-linac can be determined accurately with the introduced star-shot setup. The use of electron dense materials is not limited to the presented QA-tests but has a broad application for beam-specific QA-tests in presence of a magnetic field.

  6. CD14 dependence of TLR4 endocytosis and TRIF signaling displays ligand specificity and is dissociable in endotoxin tolerance.

    PubMed

    Rajaiah, Rajesh; Perkins, Darren J; Ireland, Derek D C; Vogel, Stefanie N

    2015-07-01

    Dimerization of Toll-like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD2) heterodimers is critical for both MyD88- and TIR-domain-containing adapter-inducing IFN-β (TRIF)-mediated signaling pathways. Recently, Zanoni et al. [(2011) Cell 147(4):868-880] reported that cluster of differentiation 14 (CD14) is required for LPS-/Escherichia coli- induced TLR4 internalization into endosomes and activation of TRIF-mediated signaling in macrophages. We confirmed their findings with LPS but report here that CD14 is not required for receptor endocytosis and downstream signaling mediated by TLR4/MD2 agonistic antibody (UT12) and synthetic small-molecule TLR4 ligands (1Z105) in murine macrophages. CD14 deficiency completely ablated the LPS-induced TBK1/IRF3 signaling axis that mediates production of IFN-β in murine macrophages without affecting MyD88-mediated signaling, including NF-κB, MAPK activation, and TNF-α and IL-6 production. However, neither the MyD88- nor TRIF-signaling pathways and their associated cytokine profiles were altered in the absence of CD14 in UT12- or 1Z105-treated murine macrophages. Eritoran (E5564), a lipid A antagonist that binds the MD2 "pocket," completely blocked LPS- and 1Z105-driven, but not UT12-induced, TLR4 dimerization and endocytosis. Furthermore, TLR4 endocytosis is induced in macrophages tolerized by exposure to either LPS or UT12 and is independent of CD14. These data indicate that TLR4 receptor endocytosis and the TRIF-signaling pathway are dissociable and that TLR4 internalization in macrophages can be induced by UT12, 1Z105, and during endotoxin tolerance in the absence of CD14.

  7. Feed-forward true carrier extraction of high baud rate phase shift keyed signals using photonic modulation stripping and low-bandwidth electronics.

    PubMed

    Slavík, Radan; Kakande, Joseph; Richardson, David J

    2011-12-19

    Retrieving the full information carried by phase shift keyed (PSK) data streams requires a reference local oscillator (LO). If the receiver utilizes digital signal processing (DSP), a free-running LO can be used, although several benefits can be derived from generating an optical LO that is locked in frequency and phase to the original signal carrier (which is unfortunately suppressed in the PSK data modulation process). Here, we present a new concept of carrier recovery. Using nonlinear optics, we strip the data modulation and derive an error signal proportional to the phase/frequency difference between a free running intradyne LO and the data-stripped signal. After extracting this frequency difference (using slow electronics), we frequency shift the free running LO by this amount, effectively obtaining a homodyne LO. The carrier is recovered to a precision of better than ±0.5 Hz and the method is tested by performing homodyne detection of a 20 Gbaud binary PSK signal.

  8. The Origin of the Multiline and g = 4.1 Electron Paramagnetic Resonance Signals from the Oxygen-Evolving System of Photosystem II

    PubMed Central

    Hansson, Örjan; Aasa, Roland; Vänngȧrd, Tore

    1987-01-01

    Continuous illumination at 200 K of photosystem (PS) II-enriched membranes generates two electron paramagnetic resonance (EPR) signals that both are connected with the S2 state: a multiline signal at g 2 and a single line at g = 4.1. From measurements at three different X-band frequencies and at 34 GHz, the g tensor of the multiline species was found to be isotropic with g = 1.982. It has an excited spin multiplet at ∼30 cm-1, inferred from the temperature-dependence of the linewidth. The intensity ratio of the g = 4.1 signal to the multiline signal was found to be almost constant from 5 to 23 K. Based on these findings and on spin quantitation of the two signals in samples with and without 4% ethanol, it is concluded that they arise from the ground doublets of paramagnetic species in different PS II centers. It is suggested that the two signals originate from separate PS II electron donors that are in a redox equilibrium with each other in the S2 state and that the g = 4.1 signal arises from monomeric Mn(IV). PMID:19431697

  9. Dual mode signaling responses of a rhodamine based probe and its immobilization onto a silica gel surface for specific mercury ion detection.

    PubMed

    Pal, Ajoy; Bag, Bamaprasad

    2015-09-14

    A 3-aminomethyl-(2-amino-1-pyridyl) coupled amino-ethyl-rhodamine-B based probe (2) exhibited simultaneous chromogenic and fluorogenic dual mode signaling responses in the presence of Hg(II) ions only among all the metal ions investigated in an organic aqueous medium. The spiro-cyclic rhodamine signaling subunit undergoes complexation induced structural transformation to result in absorption and fluorescence modulation. Its complexation induced signaling exhibited reversibility with various contrasting reagents having higher affinity towards Hg(II) ions, such as anions (AcO(-)) and competing chelating agents (En). It also exhibited Hg(II)-specific photophysical signaling responses when immobilized onto a silica gel surface attached through its amino-ethyl-receptor end, owing to its structure-conformational advantages for effective coordination. The surface modified silica appended with 2 (SiR-1), as evaluated through the FTIR spectral pattern, thermogravimetric analysis, FESEM images, elemental analysis, X-ray diffraction, surface area determination and particle size analysis, also exhibited reversible Hg(II)-specific signaling in its suspension state in an aqueous medium, enhancing the probe's utility for practical applications such as the detection, isolation and extraction of Hg(II) ions in the presence of other competitive metal ions.

  10. The role of PLDα1 in providing specificity to signal-response coupling by heterotrimeric G-protein components in Arabidopsis.

    PubMed

    Roy Choudhury, Swarup; Pandey, Sona

    2016-04-01

    Heterotrimeric G-proteins comprised of Gα, Gβ and Gγ subunits are important signal transducers in all eukaryotes. In plants, G-proteins affect multiple biotic and abiotic stress responses, as well as many developmental processes, even though their repertoire is significantly limited compared with that in metazoan systems. One canonical and three extra-large Gα, 1 Gβ and 3 Gγ proteins represent the heterotrimeric G-protein complex in Arabidopsis, and a single regulatory protein, RGS1, is one of the few known biochemical regulators of this signaling complex. This quantitative disparity between the number of signaling components and the range of processes they influence is rather intriguing. We now present evidence that the phospholipase Dα1 protein is a key component and modulator of the G-protein complex in affecting a subset of signaling pathways. We also show that the same G-protein subunits and their modulators exhibit distinct physiological and genetic interactions depending on specific signaling and developmental pathways. Such developmental plasticity and interaction specificity likely compensates for the lack of multiplicity of individual subunits, and helps to fine tune the plants' responses to constantly changing environments. PMID:26935351

  11. The Effects of Plasma Density Irregularities on the Pitch Angle Scattering of Energetic Radiation Belt Electrons due to VLF Signals from Ground Based Transmitters.

    NASA Astrophysics Data System (ADS)

    Bell, T. F.; Inan, U. S.; Kulkarni, P.; Parrot, M.

    2007-12-01

    On the basis of analytical models, it is commonly believed that VLF signals from powerful ground based transmitters determine the lifetimes of energetic radiation belt electrons (100 keV - 1.5 MeV) on L shells in the range 1.3 - 2.8 [e.g., Abel and Thorne, 1998]. The primary mechanism of interaction is believed to be gyro- resonance. To test this hypothesis, one needs to know the characteristics of the VLF signals in the radiation belts, as well as the characteristics of the energetic electron precipitation produced by these VLF signals. To these ends, Stanford University has recently carried out a series of experiments in which the 21.4 kHz signals from the US Navy transmitter in Hawaii (NPM) are keyed in a regular OFF/ON pattern designed to reveal any energetic electron precipitation that may be attributed to the transmitter signals. The subject of the present paper concerns the characteristics of the 21.4 kHz signals in the radiation belts. VLF plasma wave observations from the DEMETER spacecraft suggest that the plasma on the L shells illuminated by the NPM transmitter often contain small-scale magnetic-field-aligned plasma density irregularities. VLF waves propagating within these irregularities will generally excite lower-hybrid waves through linear mode coupling. At any given point along an L shell, the excited lower-hybrid waves will resonate with electrons of higher energy than those which resonate with the input wave. Thus the energetic electron precipitation signature due to an input VLF pulse will be different when magnetic-field-aligned plasma density irregularities are present. We compare the precipitation signatures obtained both with, and without, the irregularities and discuss how our results compare with steady state models such as that of [Abel and Thorne, 1998].

  12. SU-E-T-305: Study of the Eclipse Electron Monte Carlo Algorithm for Patient Specific MU Calculations

    SciTech Connect

    Wang, X; Qi, S; Agazaryan, N; DeMarco, J

    2014-06-01

    Purpose: To evaluate the Eclipse electron Monte Carlo (eMC) algorithm based on patient specific monitor unit (MU) calculations, and to propose a new factor which quantitatively predicts the discrepancy of MUs between the eMC algorithm and hand calculations. Methods: Electron treatments were planned for 61 patients on Eclipse (Version 10.0) using the eMC algorithm for Varian TrueBeam linear accelerators. For each patient, the same treatment beam angle was kept for a point dose calculation at dmax performed with the reference condition, which used an open beam with a 15×15 cm2 size cone and 100 SSD. A patient specific correction factor (PCF) was obtained by getting the ratio between this point dose and the calibration dose, which is 1 cGy per MU delivered at dmax. The hand calculation results were corrected by the PCFs and compared with MUs from the treatment plans. Results: The MU from the treatment plans were in average (7.1±6.1)% higher than the hand calculations. The average MU difference between the corrected hand calculations and the eMC treatment plans was (0.07±3.48)%. A correlation coefficient of 0.8 was found between (1-PCF) and the percentage difference between the treatment plan and hand calculations. Most outliers were treatment plans with small beam opening (< 4 cm) and low energy beams (6 and 9 MeV). Conclusion: For CT-based patient treatment plans, the eMC algorithm tends to generate a larger MU than hand calculations. Caution should be taken for eMC patient plans with small field sizes and low energy beams. We hypothesize that the PCF ratio reflects the influence of patient surface curvature and tissue inhomogeneity to patient specific percent depth dose (PDD) curve and MU calculations in eMC algorithm.

  13. Sex-specific disruptions in spatial memory and anhedonia in a "two hit" rat model correspond with alterations in hippocampal brain-derived neurotrophic factor expression and signaling.

    PubMed

    Hill, Rachel A; Klug, Maren; Kiss Von Soly, Szerenke; Binder, Michele D; Hannan, Anthony J; van den Buuse, Maarten

    2014-10-01

    Post-mortem studies have demonstrated reduced expression of brain-derived neurotrophic factor (BDNF) in the hippocampus of schizophrenia and major depression patients. The "two hit" hypothesis proposes that two or more major disruptions at specific time points during development are involved in the pathophysiology of these mental illnesses. However, the role of BDNF in these "two hit" effects is unclear. Our aim was to behaviorally characterize a "two hit" rat model of developmental stress accompanied by an in-depth assessment of BDNF expression and signalling. Wistar rats were exposed to neonatal maternal separation (MS) stress and/or adolescent/young-adult corticosterone (CORT) treatment. In adulthood, models of cognitive and negative symptoms of mental illness were analyzed. The hippocampus was then dissected into dorsal (DHP) and ventral (VHP) regions and analyzed by qPCR for exon-specific BDNF gene expression or by Western blot for BDNF protein expression and downstream signaling. Male "two hit" rats showed marked disruptions in short-term spatial memory (Y-maze) which were absent in females. However, female "two hit" rats showed signs of anhedonia (sucrose preference test), which were absent in males. Novel object recognition and anxiety (elevated plus maze) were unchanged by either of the two "hits". In the DHP, MS caused a male-specific increase in BDNF Exons I, II, IV, VII, and IX mRNA but a decrease in mature BDNF and phosphorylated TrkB (pTrkB) protein expression in adulthood. In the VHP, BDNF transcript expression was unchanged; however, in female rats only, MS significantly decreased mature BDNF and pTrkB protein expression in adulthood. These data demonstrate that MS causes region-specific and sex-specific long-term effects on BDNF expression and signaling and, importantly, mRNA expression does not always infer protein expression. Alterations to BDNF signaling may mediate the sex-specific effects of developmental stress on anhedonic behaviors.

  14. Cell Type-Specific Activation of AKT and ERK Signaling Pathways by Small Negatively-Charged Magnetic Nanoparticles

    NASA Astrophysics Data System (ADS)

    Rauch, Jens; Kolch, Walter; Mahmoudi, Morteza

    2012-11-01

    The interaction of nanoparticles (NPs) with living organisms has become a focus of public and scientific debate due to their potential wide applications in biomedicine, but also because of unwanted side effects. Here, we show that superparamagnetic iron oxide NPs (SPIONs) with different surface coatings can differentially affect signal transduction pathways. Using isogenic pairs of breast and colon derived cell lines we found that the stimulation of ERK and AKT signaling pathways by SPIONs is selectively dependent on the cell type and SPION type. In general, cells with Ras mutations respond better than their non-mutant counterparts. Small negatively charged SPIONs (snSPIONs) activated ERK to a similar extent as epidermal growth factor (EGF), and used the same upstream signaling components including activation of the EGF receptor. Importantly, snSPIONs stimulated the proliferation of Ras transformed breast epithelial cells as efficiently as EGF suggesting that NPs can mimic physiological growth factors.

  15. Development of an efficient signal amplification strategy for label-free enzyme immunoassay using two site-specific biotinylated recombinant proteins.

    PubMed

    Tang, Jin-Bao; Tang, Ying; Yang, Hong-Ming

    2015-02-15

    Constructing a recombinant protein between a reporter enzyme and a detector protein to produce a homogeneous immunological reagent is advantageous over random chemical conjugation. However, the approach hardly recombines multiple enzymes in a difunctional fusion protein, which results in insufficient amplification of the enzymatic signal, thereby limiting its application in further enhancement of analytical signal. In this study, two site-specific biotinylated recombinant proteins, namely, divalent biotinylated alkaline phosphatase (AP) and monovalent biotinylated ZZ domain, were produced by employing the Avitag-BirA system. Through the high streptavidin (SA)-biotin interaction, the divalent biotinylated APs were clustered in the SA-biotin complex and then incorporated with the biotinylated ZZ. This incorporation results in the formation of a functional macromolecule that involves numerous APs, thereby enhancing the enzymatic signal, and in the production of several ZZ molecules for the interaction with immunoglobulin G (IgG) antibody. The advantage of this signal amplification strategy is demonstrated through ELISA, in which the analytical signal was substantially enhanced, with a 32-fold increase in the detection sensitivity compared with the ZZ-AP fusion protein approach. The proposed immunoassay without chemical modification can be an alternative strategy to enhance the analytical signals in various applications involving immunosensors and diagnostic chips, given that the label-free IgG antibody is suitable for the ZZ protein.

  16. Covalent functionalization of gold nanoparticles as electronic bridges and signal amplifiers towards an electrochemical immunosensor for botulinum neurotoxin type A.

    PubMed

    Liu, Guozhen; Zhang, Yin; Guo, Wenqi

    2014-11-15

    This work introduced an efficient approach for modification of AuNPs with multicomponents by diazonium salt couplings. The multifunctionalized AuNPs with protruding functional groups that allow simple bioconjugation to large amounts of biomolecules have been successfully used as electronic bridges and signal amplifiers for an electrochemical immunosensor towards the detection of BoNT/A. The one-step anchoring AuNPs strategy has greatly increased the efficiency for attachment of biomolecules and subsequently increased the sensitivity. Sensitivity was further amplified by preparation of bioconjugates particles containing horseradish peroxidase (HRP) labels along with detection antibodies (AbL) attached to AuNPs. The immunosensor can be used for the detection of BoNT/A over the range of 4-35 pg mL(-1) with the lowest detection limit of 1 pg mL(-1) and assay time of 10 min. The herein sensing strategy is rapid, robust, selective, sensitive, and is promising for future fabrication of point-of-care devices.

  17. Electronically controlled agile lens-based broadband variable photonic delay line for photonic and radio frequency signal processing.

    PubMed

    Riza, Nabeel A; Reza, Syed Azer; Marraccini, Philip J

    2010-12-10

    To the best of our knowledge, proposed for the first time is the design of an optically broadband variable photonic delay line (VPDL) using an electronically controlled variable focus lens (ECVFL), mirror motion, and beam-conditioned free-space laser beam propagation. This loss-minimized fiber-coupled VPDL design using micro-optic components has the ability to simultaneously provide optical attenuation controls and analog-mode high-resolution (subpicoseconds) continuous delays over a moderate (e.g., <5 ns) range of time delays. An example VPDL design using a liquid-based ECVFL demonstrates up to a 1 ns time-delay range with >10 dB optical attenuation controls. The proposed VPDL is deployed to demonstrate a two-tap RF notch filter with tuned notches at 854.04 and 855.19 MHz with 22.6 dB notch depth control via VPDL attenuation control operations. The proposed VPDL is useful in signal conditioning applications requiring fiber-coupled broadband light time delay and attenuation controls.

  18. Ototoxicity and noise trauma: electron transfer, reactive oxygen species, cell signaling, electrical effects, and protection by antioxidants: practical medical aspects.

    PubMed

    Kovacic, Peter; Somanathan, Ratnasamy

    2008-01-01

    Ototoxins are substances of various structures and classes. This review provides extensive evidence for involvement of electron transfer (ET), reactive oxygen species (ROS) and oxidative stress (OS) as a unifying theme. Successful application is made to the large majority of ototoxins, as well as noise trauma. We believe it is not coincidental that these toxins generally incorporate ET functionalities (quinone, metal complex, ArNO(2), or conjugated iminium) either per se or in metabolites, potentially giving rise to ROS by redox cycling. Some categories, e.g., peroxides and noise, appear to operate via non-ET routes in generating OS. These highly reactive entities can then inflict injury via OS upon various constituents of the ear apparatus. The theoretical framework is supported by the extensive literature on beneficial effects of antioxidants, both for toxins and noise. Involvement of cell signaling and electrical effects are discussed. This review is the first comprehensive one based on a unified mechanistic approach. Various practical medical aspects are also addressed. There is extensive documentation for beneficial effects of antioxidants whose use might be recommended clinically for prevention of ototoxicity and noise trauma. Recent research indicates that catalytic antioxidants may be more effective. In addition to ototoxicity, a widespread problem consists of ear infections by bacteria which are demonstrating increasing resistance to conventional therapies. A recent, novel approach to improved drugs involves use of agents which inhibit quorum sensors that play important roles in bacterial functioning. Prevention of ear injury by noise trauma is also discussed, along with ear therapeutics.

  19. Detection of prostate-specific antigen with biomolecule-gated AlGaN/GaN high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Li, Jia-dong; Cheng, Jun-jie; Miao, Bin; Wei, Xiao-wei; Xie, Jie; Zhang, Jin-cheng; Zhang, Zhi-qiang; Wu, Dong-min

    2014-07-01

    In order to improve the sensitivity of AlGaN/GaN high electron mobility transistor (HEMT) biosensors, a simple biomolecule-gated AlGaN/GaN HEMT structure was designed and successfully fabricated for prostate specific antigen (PSA) detection. UV/ozone was used to oxidize the GaN surface and then a 3-aminopropyl trimethoxysilane (APTES) self-assembled monolayer was bound to the sensing region. This monolayer serves as a binding layer for attachment of the prostate specific antibody (anti-PSA). The biomolecule-gated AlGaN/GaN HEMT sensor shows a rapid and sensitive response when the target prostate-specific antigen in buffer solution was added to the antibody-immobilized sensing area. The current change showed a logarithm relationship against the PSA concentration from 0.1 pg/ml to 0.993 ng/ml. The sensitivity of 0.215% is determined for 0.1 pg/ml PSA solution. The above experimental result of the biomolecule-gated AlGaN/GaN HEMT biosensor suggested that this biosensor might be a useful tool for prostate cancer screening.

  20. Systemic signaling of the plant nitrogen status triggers specific transcriptome responses depending on the nitrogen source in Medicago truncatula.

    PubMed

    Ruffel, Sandrine; Freixes, Sandra; Balzergue, Sandrine; Tillard, Pascal; Jeudy, Christian; Martin-Magniette, Marie Laure; van der Merwe, Margaretha J; Kakar, Klementina; Gouzy, Jerôme; Fernie, Alisdair R; Udvardi, Michael; Salon, Christophe; Gojon, Alain; Lepetit, Marc

    2008-04-01

    Legumes can acquire nitrogen (N) from NO(3)(-), NH(4)(+), and N(2) (through symbiosis with Rhizobium bacteria); however, the mechanisms by which uptake and assimilation of these N forms are coordinately regulated to match the N demand of the plant are currently unknown. Here, we find by use of the split-root approach in Medicago truncatula plants that NO(3)(-) uptake, NH(4)(+) uptake, and N(2) fixation are under general control by systemic signaling of plant N status. Indeed, irrespective of the nature of the N source, N acquisition by one side of the root system is repressed by high N supply to the other side. Transcriptome analysis facilitated the identification of over 3,000 genes that were regulated by systemic signaling of the plant N status. However, detailed scrutiny of the data revealed that the observation of differential gene expression was highly dependent on the N source. Localized N starvation results, in the unstarved roots of the same plant, in a strong compensatory up-regulation of NO(3)(-) uptake but not of either NH(4)(+) uptake or N(2) fixation. This indicates that the three N acquisition pathways do not always respond similarly to a change in plant N status. When taken together, these data indicate that although systemic signals of N status control root N acquisition, the regulatory gene networks targeted by these signals, as well as the functional response of the N acquisition systems, are predominantly determined by the nature of the N source.

  1. Chloroplasts of Arabidopsis are the source and a primary target of a plant-specific programmed cell death signaling pathway.

    PubMed

    Kim, Chanhong; Meskauskiene, Rasa; Zhang, Shengrui; Lee, Keun Pyo; Lakshmanan Ashok, Munusamy; Blajecka, Karolina; Herrfurth, Cornelia; Feussner, Ivo; Apel, Klaus

    2012-07-01

    Enhanced levels of singlet oxygen ((1)O(2)) in chloroplasts trigger programmed cell death. The impact of (1)O(2) production in chloroplasts was monitored first in the conditional fluorescent (flu) mutant of Arabidopsis thaliana that accumulates (1)O(2) upon a dark/light shift. The onset of (1)O(2) production is rapidly followed by a loss of chloroplast integrity that precedes the rupture of the central vacuole and the final collapse of the cell. Inactivation of the two plastid proteins EXECUTER (EX1) and EX2 in the flu mutant abrogates these responses, indicating that disintegration of chloroplasts is due to EX-dependent signaling rather than (1)O(2) directly. In flu seedlings, (1)O(2)-mediated cell death signaling operates as a default pathway that results in seedlings committing suicide. By contrast, EX-dependent signaling in the wild type induces the formation of microlesions without decreasing the viability of seedlings. (1)O(2)-mediated and EX-dependent loss of plastid integrity and cell death in these plants occurs only in cells containing fully developed chloroplasts. Our findings support an as yet unreported signaling role of (1)O(2) in the wild type exposed to mild light stress that invokes photoinhibition of photosystem II without causing photooxidative damage of the plant.

  2. Suppression of Bmp4 signaling by the zinc-finger repressors Osr1 and Osr2 is required for Wnt/β-catenin-mediated lung specification in Xenopus

    PubMed Central

    Rankin, Scott A.; Gallas, Alyssa L.; Neto, Ana; Gómez-Skarmeta, José Luis; Zorn, Aaron M.

    2012-01-01

    Embryonic development of the respiratory system is regulated by a series of mesenchymal-epithelial interactions that are only partially understood. Mesenchymal FGF and Wnt2/Wnt2b signaling are implicated in specification of mammalian pulmonary progenitors from the ventral foregut endoderm, but their epistatic relationship and downstream targets are largely unknown. In addition, how wnt2 and wnt2b are regulated in the developing foregut mesenchyme is unknown. We show that the Odd-skipped-related (Osr) zinc-finger transcriptional repressors Osr1 and Osr2 are redundantly required for Xenopus lung specification in a molecular pathway linking foregut pattering by FGFs to Wnt-mediated lung specification and RA-regulated lung bud growth. FGF and RA signals are required for robust osr1 and osr2 expression in the foregut endoderm and surrounding lateral plate mesoderm (lpm) prior to respiratory specification. Depletion of both Osr1 and Osr2 (Osr1/Osr2) results in agenesis of the lungs, trachea and esophagus. The foregut lpm of Osr1/Osr2-depleted embryos fails to express wnt2, wnt2b and raldh2, and consequently Nkx2.1+ progenitors are not specified. Our data suggest that Osr1/Osr2 normally repress bmp4 expression in the lpm, and that BMP signaling negatively regulates the wnt2b domain. These results significantly advance our understanding of early lung development and may impact strategies to differentiate respiratory tissue from stem cells. PMID:22791896

  3. Dual Specificity Phosphatase 5, a Specific Negative Regulator of ERK Signaling, Is Induced by Serum Response Factor and Elk-1 Transcription Factor

    PubMed Central

    Buffet, Camille; Catelli, Maria-Grazia; Hecale-Perlemoine, Karine; Bricaire, Léopoldine; Garcia, Camille; Gallet-Dierick, Anne; Rodriguez, Stéphanie; Cormier, Françoise; Groussin, Lionel

    2015-01-01

    Serum stimulation of mammalian cells induces, via the MAPK pathway, the nuclear protein DUSP5 (dual-specificity phosphatase 5), which specifically interacts with and inactivates the ERK1/2 MAP kinases. However, molecular mechanisms underlying DUSP5 induction are not well known. Here, we found that the DUSP5 mRNA induction depends on a transcriptional regulation by the MAPK pathway, without any modification of the mRNA stability. Two contiguous CArG boxes that bind serum response factor (SRF) were found in a 1 Kb promoter region, as well as several E twenty-six transcription factor family binding sites (EBS). These sites potentially bind Elk-1, a transcription factor activated by ERK1/2. Using wild type or mutated DUSP5 promoter reporters, we demonstrated that SRF plays a crucial role in serum induction of DUSP5 promoter activity, the proximal CArG box being important for SRF binding in vitro and in living cells. Moreover, in vitro and in vivo binding data of Elk-1 to the same promoter region further demonstrate a role for Elk-1 in the transcriptional regulation of DUSP5. SRF and Elk-1 form a ternary complex (Elk-1-SRF-DNA) on DUSP5 promoter, consequently providing a link to an important negative feedback tightly regulating phosphorylated ERK levels. PMID:26691724

  4. Dual Specificity Phosphatase 5, a Specific Negative Regulator of ERK Signaling, Is Induced by Serum Response Factor and Elk-1 Transcription Factor.

    PubMed

    Buffet, Camille; Catelli, Maria-Grazia; Hecale-Perlemoine, Karine; Bricaire, Léopoldine; Garcia, Camille; Gallet-Dierick, Anne; Rodriguez, Stéphanie; Cormier, Françoise; Groussin, Lionel

    2015-01-01

    Serum stimulation of mammalian cells induces, via the MAPK pathway, the nuclear protein DUSP5 (dual-specificity phosphatase 5), which specifically interacts with and inactivates the ERK1/2 MAP kinases. However, molecular mechanisms underlying DUSP5 induction are not well known. Here, we found that the DUSP5 mRNA induction depends on a transcriptional regulation by the MAPK pathway, without any modification of the mRNA stability. Two contiguous CArG boxes that bind serum response factor (SRF) were found in a 1 Kb promoter region, as well as several E twenty-six transcription factor family binding sites (EBS). These sites potentially bind Elk-1, a transcription factor activated by ERK1/2. Using wild type or mutated DUSP5 promoter reporters, we demonstrated that SRF plays a crucial role in serum induction of DUSP5 promoter activity, the proximal CArG box being important for SRF binding in vitro and in living cells. Moreover, in vitro and in vivo binding data of Elk-1 to the same promoter region further demonstrate a role for Elk-1 in the transcriptional regulation of DUSP5. SRF and Elk-1 form a ternary complex (Elk-1-SRF-DNA) on DUSP5 promoter, consequently providing a link to an important negative feedback tightly regulating phosphorylated ERK levels.

  5. Empirical Prediction of Electronic Potentials of Single-Walled Carbon Nanotubes With a Specific Chirality (n,m)

    PubMed Central

    Hirana, Yasuhiko; Juhasz, Gergely; Miyauchi, Yuhei; Mouri, Shinichiro; Matsuda, Kazunari; Nakashima, Naotoshi

    2013-01-01

    The determination of the electronic states of single-walled carbon nanotubes (SWNTs) with a specific chirality has been a central issue in the science of SWNTs. Here we present the empirical equations with fitting parameters for the determination of the reduction and oxidation potentials of SWNTs for a wide range of diameters and chiral angles. In these equations, a distinct chirality family dependence of the reduction potentials is observed, while the oxidation potentials show a simple diameter dependence nearly proportional to the inversed nanotube diameter. Based on observations of the asymmetric chirality dependence between the reduction and oxidation potentials, the Fermi levels of the SWNTs were revealed to have a definite chirality family dependence, which indicates that the work functions of the SWNTs with small diameters deviate from the values for the large diameter SWNTs and graphene. We also performed quantum chemical calculations to compare the experiment to the calculations. PMID:24129863

  6. Modulation of c-Jun N-Terminal Kinase Signaling and Specific Glucocorticoid Receptor Phosphorylation in the Treatment of Major Depression

    PubMed Central

    Jovicic, Milica J.; Lukic, Iva; Radojcic, Marija; Adzic, Miroslav; Maric, Nadja P.

    2015-01-01

    Glucocorticoid resistance is a common finding in major depressive disorder. Increased glucocorticoid receptor (GR) phosphorylation at serine 226 is associated with increased glucocorticoid resistance. Previously we have demonstrated that depressed patients exhibit higher levels of GR phosphorylated at serine 226 compared to healthy controls. The enzyme that is involved in this specific GR phosphorylation is c-Jun N-Terminal Kinase (JNK). We propose that modulation of glucocorticoid phosphorylation at serine 226, by targeting JNK signaling pathway, could be a potential strategy for antidepressant treatment. We base this assumption on the results of previous research that examined GR phosphorylation and JNK signaling in animal models and human studies. We also discuss the potential challenges in targeting JNK signaling pathway in depression. PMID:26052031

  7. Specificities of applying pseudorandom sound signals to measuring impulse responses on the shelf of the Sea of Japan

    NASA Astrophysics Data System (ADS)

    Bezotvetnykh, V. V.; Burenin, A. V.; Morgunov, Yu. N.; Strobykin, D. S.

    2012-01-01

    Solving the problems of underwater acoustic communication and navigation for controlling underwater objects greatly depends on a correct estimation of the hydrological and acoustical environment in the region. Analysis of the domestic and foreign experience in the field of navigational support of self-contained underwater devises shows that, to solve the problem, it is technically and economically advantageous to deploy a set of fixed sources of navigation signals in the region with a range of coverage that is at least not less than the size of the region of interest. At long distances and, especially, in a shallow-water sea, the key factors in solving the problem of navigation are correct determination of the efficient sound speed and the time of signal propagation for each path connecting sources and receivers.

  8. β-Catenin Signaling Biases Multipotent Lingual Epithelial Progenitors to Differentiate and Acquire Specific Taste Cell Fates.

    PubMed

    Gaillard, Dany; Xu, Mingang; Liu, Fei; Millar, Sarah E; Barlow, Linda A

    2015-05-01

    Continuous taste bud cell renewal is essential to maintain taste function in adults; however, the molecular mechanisms that regulate taste cell turnover are unknown. Using inducible Cre-lox technology, we show that activation of β-catenin signaling in multipotent lingual epithelial progenitors outside of taste buds diverts daughter cells from a general epithelial to a taste bud fate. Moreover, while taste buds comprise 3 morphological types, β-catenin activation drives overproduction of primarily glial-like Type I taste cells in both anterior fungiform (FF) and posterior circumvallate (CV) taste buds, with a small increase in Type II receptor cells for sweet, bitter and umami, but does not alter Type III sour detector cells. Beta-catenin activation in post-mitotic taste bud precursors likewise regulates cell differentiation; forced activation of β-catenin in these Shh+ cells promotes Type I cell fate in both FF and CV taste buds, but likely does so non-cell autonomously. Our data are consistent with a model where β-catenin signaling levels within lingual epithelial progenitors dictate cell fate prior to or during entry of new cells into taste buds; high signaling induces Type I cells, intermediate levels drive Type II cell differentiation, while low levels may drive differentiation of Type III cells.

  9. Smooth muscle cell-specific Tgfbr1 deficiency promotes aortic aneurysm formation by stimulating multiple signaling events

    PubMed Central

    Yang, Pu; Schmit, Bradley M.; Fu, Chunhua; DeSart, Kenneth; Oh, S. Paul; Berceli, Scott A.; Jiang, Zhihua

    2016-01-01

    Transforming growth factor (TGF)-β signaling disorder has emerged as a common molecular signature for aortic aneurysm development. The timing of postnatal maturation plays a key role in dictating the biological outcome of TGF-β signaling disorders in the aortic wall. In this study, we investigated the impact of deficiency of TGFβ receptors on the structural homeostasis of mature aortas. We used an inducible Cre-loxP system driven by a Myh11 promoter to delete Tgfbr1, Tgfbr2, or both in smooth muscle cells (SMCs) of adult mice. TGFBR1 deficiency resulted in rapid and severe aneurysmal degeneration, with 100% penetrance of ascending thoracic aortas, whereas TGFBR2 deletion only caused mild aortic pathology with low (26%) lesion prevalence. Removal of TGFBR2 attenuated the aortic pathology caused by TGFBR1 deletion and correlated with a reduction of early ERK phosphorylation. In addition, the production of angiotensin (Ang)-converting enzyme was upregulated in TGFBR1 deficient aortas at the early stage of aneurysmal degeneration. Inhibition of ERK phosphorylation or blockade of AngII type I receptor AT1R prevented aneurysmal degeneration of TGFBR1 deficient aortas. In conclusion, loss of SMC-Tgfbr1 triggers multiple deleterious pathways, including abnormal TGFBR2, ERK, and AngII/AT1R signals that disrupt aortic wall homeostasis to cause aortic aneurysm formation. PMID:27739498

  10. Integrative Tissue-Specific Functional Annotations in the Human Genome Provide Novel Insights on Many Complex Traits and Improve Signal Prioritization in Genome Wide Association Studies

    PubMed Central

    Wang, Qian; He, Beixin Julie; Zhao, Hongyu

    2016-01-01

    Extensive efforts have been made to understand genomic function through both experimental and computational approaches, yet proper annotation still remains challenging, especially in non-coding regions. In this manuscript, we introduce GenoSkyline, an unsupervised learning framework to predict tissue-specific functional regions through integrating high-throughput epigenetic annotations. GenoSkyline successfully identified a variety of non-coding regulatory machinery including enhancers, regulatory miRNA, and hypomethylated transposable elements in extensive case studies. Integrative analysis of GenoSkyline annotations and results from genome-wide association studies (GWAS) led to novel biological insights on the etiologies of a number of human complex traits. We also explored using tissue-specific functional annotations to prioritize GWAS signals and predict relevant tissue types for each risk locus. Brain and blood-specific annotations led to better prioritization performance for schizophrenia than standard GWAS p-values and non-tissue-specific annotations. As for coronary artery disease, heart-specific functional regions was highly enriched of GWAS signals, but previously identified risk loci were found to be most functional in other tissues, suggesting a substantial proportion of still undetected heart-related loci. In summary, GenoSkyline annotations can guide genetic studies at multiple resolutions and provide valuable insights in understanding complex diseases. GenoSkyline is available at http://genocanyon.med.yale.edu/GenoSkyline. PMID:27058395

  11. Structure and cell-specific expression of a cloned human retinol binding protein gene: the 5'-flanking region contains hepatoma specific transcriptional signals.

    PubMed

    D'Onofrio, C; Colantuoni, V; Cortese, R

    1985-08-01

    Human plasma retinol binding protein (RBP) is coded by a single gene and is specifically synthesized in the liver. We have characterized a lambda clone, from a human DNA library, carrying the gene coding for plasma RBP. Southern blot analysis and DNA sequencing show that the gene is composed of six exons and five introns. Primer elongation and S1 mapping experiments allowed the definition of the initiation of transcription and the identification of the putative promoter. The 5'-flanking region of the RBP gene was fused upstream to the coding sequence of the bacterial enzyme chloramphenicol acetyl transferase (CAT): the chimeric gene was introduced, by calcium phosphate precipitation, into the human hepatoma cell line Hep G2 and into HeLa cells. Efficient expression of CAT was obtained only in Hep G2. Primer elongation analysis of the RNA extracted from transfected Hep G2 showed that initiation of transcription of the transfected chimeric gene occurs at a position identical to that of the natural gene. Transcriptional analysis of Bal31 deletions from the 3' end of the RBP 5'-flanking DNA allowed the identification of the RBP gene promoter.

  12. The electronic diagnosis of caries in pits and fissures: site-specific stable conductance readings or cumulative resistance readings?

    PubMed

    Ricketts, D N; Kidd, E A; Wilson, R F

    1997-01-01

    A prototype electronic caries meter (ECM II; LODE, Groningen. The Netherlands) was designed to deliver a conductance reading when the reading had remained stable for 3 consecutive seconds. The aim of this study was to determine whether this type of stable conductance reading was optimal for caries diagnosis. The ECM II was connected to a graphic recorder which enabled the continuous resistance to be recorded. The graphic recording was calibrated using a standard, variable resistance box. Stable conductance readings were taken for 76 sites on 32 extracted teeth with no visible sign of cavitation at an airflow of 7.5 l/min. Simultaneous graphic recording of resistance was continued for 10 s and cumulative resistance measurements were calculated by adding the resistance values at 1-second intervals. Histological validation of caries status was carried out on macroradiographs of sections cut to include sample sites. The histological picture was compared with the stable conductance reading and the cumulative resistance value for each site. Sensitivity and specificity values were calculated by randomly choosing stable conductance and cumulative resistance values to differentiate sound and carious sites. The results were presented as a series of receiver operating characteristics (ROC) curves and the optimum sensitivity and specificity values determined. 33% of sites had enamel caries and 32% had enamel and dentine caries. Results showed that both stable conductance readings and cumulative resistance measurements gave high and comparable sensitivity and specificity values for the diagnosis of dentine caries (sens. 92%, spec. 87% and sens. 88%, spec. 81%, respectively). However, when intra-examiner reproducibility was checked, stable conductance readings were more repeatable and achieved in shorter clinical time. In conclusion, stable conductance readings appear to be the most suitable for occlusal caries diagnosis.

  13. Herbivore-Specific, Density-Dependent Induction of Plant Volatiles: Honest or “Cry Wolf” Signals?

    PubMed Central

    Shiojiri, Kaori; Ozawa, Rika; Kugimiya, Soichi; Uefune, Masayoshi; van Wijk, Michiel; Sabelis, Maurice W.; Takabayashi, Junji

    2010-01-01

    Plants release volatile chemicals upon attack by herbivorous arthropods. They do so commonly in a dose-dependent manner: the more herbivores, the more volatiles released. The volatiles attract predatory arthropods and the amount determines the probability of predator response. We show that seedlings of a cabbage variety (Brassica oleracea var. capitata, cv Shikidori) also show such a response to the density of cabbage white (Pieris rapae) larvae and attract more (naive) parasitoids (Cotesia glomerata) when there are more herbivores on the plant. However, when attacked by diamondback moth (Plutella xylostella) larvae, seedlings of the same variety (cv Shikidori) release volatiles, the total amount of which is high and constant and thus independent of caterpillar density, and naive parasitoids (Cotesia vestalis) of diamondback moth larvae fail to discriminate herbivore-rich from herbivore-poor plants. In contrast, seedlings of another cabbage variety of B. oleracea (var. acephala: kale) respond in a dose-dependent manner to the density of diamondback moth larvae and attract more parasitoids when there are more herbivores. Assuming these responses of the cabbage cultivars reflect behaviour of at least some genotypes of wild plants, we provide arguments why the behaviour of kale (B. oleracea var acephala) is best interpreted as an honest signaling strategy and that of cabbage cv Shikidori (B. oleracea var capitata) as a “cry wolf” signaling strategy, implying a conflict of interest between the plant and the enemies of its herbivores: the plant profits from being visited by the herbivore's enemies, but the latter would be better off by visiting other plants with more herbivores. If so, evolutionary theory on alarm signaling predicts consequences of major interest to students of plant protection, tritrophic systems and communication alike. PMID:20808961

  14. Large-scale profiling of signalling pathways reveals an asthma specific signature in bronchial smooth muscle cells

    PubMed Central

    Alexandrova, Elena; Nassa, Giovanni; Corleone, Giacomo; Buzdin, Anton; Aliper, Alexander M.; Terekhanova, Nadezhda; Shepelin, Denis; Zhavoronkov, Alexander; Tamm, Michael; Milanesi, Luciano; Weisz, Alessandro

    2016-01-01

    Background Bronchial smooth muscle (BSM) cells from asthmatic patients maintain in vitro a distinct hyper-reactive (“primed”) phenotype, characterized by increased release of pro-inflammatory factors and mediators, as well as hyperplasia and/or hypertrophy. This “primed” phenotype helps to understand pathogenesis of asthma, as changes in BSM function are essential for manifestation of allergic and inflammatory responses and airway wall remodelling. Objective To identify signalling pathways in cultured primary BSMs of asthma patients and non-asthmatic subjects by genome wide profiling of differentially expressed mRNAs and activated intracellular signalling pathways (ISPs). Methods Transcriptome profiling by cap-analysis-of-gene-expression (CAGE), which permits selection of preferentially capped mRNAs most likely to be translated into proteins, was performed in human BSM cells from asthmatic (n=8) and non-asthmatic (n=6) subjects and OncoFinder tool were then exploited for identification of ISP deregulations. Results CAGE revealed >600 RNAs differentially expressed in asthma vs control cells (p≤0.005), with asthma samples showing a high degree of similarity among them. Comprehensive ISP activation analysis revealed that among 269 pathways analysed, 145 (p<0.05) or 103 (p<0.01) are differentially active in asthma, with profiles that clearly characterize BSM cells of asthmatic individuals. Notably, we identified 7 clusters of coherently acting pathways functionally related to the disease, with ISPs down-regulated in asthma mostly targeting cell death-promoting pathways and up-regulated ones affecting cell growth and proliferation, inflammatory response, control of smooth muscle contraction and hypoxia-related signalization. Conclusions These first-time results can now be exploited toward development of novel therapeutic strategies targeting ISP signatures linked to asthma pathophysiology. PMID:26863634

  15. Liver-specific expression of carboxylesterase 1g/esterase-x reduces hepatic steatosis, counteracts dyslipidemia and improves insulin signaling.

    PubMed

    Bahitham, Wesam; Watts, Russell; Nelson, Randal; Lian, Jihong; Lehner, Richard

    2016-05-01

    Ces1g/Es-x deficiency in mice results in weight gain, insulin resistance, fatty liver and hyperlipidemia through upregulation of de novo lipogenesis and oversecretion of triacylglycerol (TG)-rich lipoproteins. Here, we show that restoration of Ces1g/Es-x expression only in the liver significantly reduced hepatic TG concentration accompanied by decreased size of lipid droplets, reduced secretion of very low-density lipoproteins and improved insulin-mediated signal transduction in the liver. Collectively, these results demonstrate that hepatic Ces1g/Es-x plays a critical role in limiting hepatic steatosis, very low-density lipoprotein assembly and in augmenting insulin sensitivity.

  16. Liver-specific expression of carboxylesterase 1g/esterase-x reduces hepatic steatosis, counteracts dyslipidemia and improves insulin signaling.

    PubMed

    Bahitham, Wesam; Watts, Russell; Nelson, Randal; Lian, Jihong; Lehner, Richard

    2016-05-01

    Ces1g/Es-x deficiency in mice results in weight gain, insulin resistance, fatty liver and hyperlipidemia through upregulation of de novo lipogenesis and oversecretion of triacylglycerol (TG)-rich lipoproteins. Here, we show that restoration of Ces1g/Es-x expression only in the liver significantly reduced hepatic TG concentration accompanied by decreased size of lipid droplets, reduced secretion of very low-density lipoproteins and improved insulin-mediated signal transduction in the liver. Collectively, these results demonstrate that hepatic Ces1g/Es-x plays a critical role in limiting hepatic steatosis, very low-density lipoprotein assembly and in augmenting insulin sensitivity. PMID:26976727

  17. CuO-induced signal amplification strategy for multiplexed photoelectrochemical immunosensing using CdS sensitized ZnO nanotubes arrays as photoactive material and AuPd alloy nanoparticles as electron sink.

    PubMed

    Sun, Guoqiang; Zhang, Yan; Kong, Qingkun; Zheng, Xiaoxiao; Yu, Jinghua; Song, Xianrang

    2015-04-15

    In this work, multiplexed photoelectrochemical (PEC) immunoassays are introduced into an indium tin oxide (ITO) device. Firstly, the ITO device is fabricated using a simple acid etch treatment method. Secondly, AuPd alloy nanoparticles are electro-deposited on ITO working electrodes as electron sink to construct the immunosensor platform. After that, ZnO nanotubes (ZNTs) arrays are synthesized via chemical etching of ZnO nanorods that are grown on AuPd surface by electrochemical deposition method. Subsequently, CdS is electro-deposited on ZNTs arrays and used as photoactive material. Then, CuO nanoseeds are labeled with signal antibodies and firstly used as PEC signal amplification label. The introduction of CuO brings signal amplification because of the conduction band (CB) of both CuO and ZnO are lower than that of CdS, CuO will compete the photo-induced electrons in CB of CdS with ZnO, leading to the decrease of the photocurrent intensity. Using cancer antigen 125, prostate specific antigen and α-fetoprotein as model analytes, the proposed immunoassay exhibits excellent precision and sensitivity. Meanwhile, this work provides a promising, addressable and simple strategy for the multi-detection of tumor markers.

  18. Antigen-specific TCR–pMHC catch bonds trigger signaling by fast accumulation of force-prolonged bond lifetimes

    PubMed Central

    Liu, Baoyu; Chen, Wei; Evavold, Brian D.; Zhu, Cheng

    2014-01-01

    Summary TCR–pMHC interactions initiate adaptive immune responses, but the mechanism of how such interactions under force induce T-cell signaling is unclear. We show that force prolongs lifetimes of single TCR–pMHC bonds for agonists (catch bonds) but shortens those for antagonists (slip bonds). Both magnitude and duration of force are important as the highest Ca2+ responses were induced by 10 pN via both pMHC catch bonds whose lifetime peaks at this force and anti-TCR slip bonds whose maximum lifetime occurs at 0 pN. High Ca2+ levels require early and rapid accumulation of bond lifetimes whereas short-lived bonds that slow early accumulation of lifetimes correspond to low Ca2+ responses. Our data support a model where force on the TCR induces signaling events depending on its magnitude, duration, frequency, and timing, such that agonists form catch bonds that trigger the T cell digitally, whereas antagonists form slip bonds that fail to activate. PMID:24725404

  19. Cortical depth-specific microvascular dilation underlies laminar differences in blood oxygenation level-dependent functional MRI signal

    PubMed Central

    Tian, Peifang; Teng, Ivan C.; May, Larry D.; Kurz, Ronald; Lu, Kun; Scadeng, Miriam; Hillman, Elizabeth M. C.; De Crespigny, Alex J.; D’Arceuil, Helen E.; Mandeville, Joseph B.; Marota, John J. A.; Rosen, Bruce R.; Liu, Thomas T.; Boas, David A.; Buxton, Richard B.; Dale, Anders M.; Devor, Anna

    2010-01-01

    Changes in neuronal activity are accompanied by the release of vasoactive mediators that cause microscopic dilation and constriction of the cerebral microvasculature and are manifested in macroscopic blood oxygenation level-dependent (BOLD) functional MRI (fMRI) signals. We used two-photon microscopy to measure the diameters of single arterioles and capillaries at different depths within the rat primary somatosensory cortex. These measurements were compared with cortical depth-resolved fMRI signal changes. Our microscopic results demonstrate a spatial gradient of dilation onset and peak times consistent with “upstream” propagation of vasodilation toward the cortical surface along the diving arterioles and “downstream” propagation into local capillary beds. The observed BOLD response exhibited the fastest onset in deep layers, and the “initial dip” was most pronounced in layer I. The present results indicate that both the onset of the BOLD response and the initial dip depend on cortical depth and can be explained, at least in part, by the spatial gradient of delays in microvascular dilation, the fastest response being in the deep layers and the most delayed response in the capillary bed of layer I. PMID:20696904

  20. Cortical depth-specific microvascular dilation underlies laminar differences in blood oxygenation level-dependent functional MRI signal.

    PubMed

    Tian, Peifang; Teng, Ivan C; May, Larry D; Kurz, Ronald; Lu, Kun; Scadeng, Miriam; Hillman, Elizabeth M C; De Crespigny, Alex J; D'Arceuil, Helen E; Mandeville, Joseph B; Marota, John J A; Rosen, Bruce R; Liu, Thomas T; Boas, David A; Buxton, Richard B; Dale, Anders M; Devor, Anna

    2010-08-24

    Changes in neuronal activity are accompanied by the release of vasoactive mediators that cause microscopic dilation and constriction of the cerebral microvasculature and are manifested in macroscopic blood oxygenation level-dependent (BOLD) functional MRI (fMRI) signals. We used two-photon microscopy to measure the diameters of single arterioles and capillaries at different depths within the rat primary somatosensory cortex. These measurements were compared with cortical depth-resolved fMRI signal changes. Our microscopic results demonstrate a spatial gradient of dilation onset and peak times consistent with "upstream" propagation of vasodilation toward the cortical surface along the diving arterioles and "downstream" propagation into local capillary beds. The observed BOLD response exhibited the fastest onset in deep layers, and the "initial dip" was most pronounced in layer I. The present results indicate that both the onset of the BOLD response and the initial dip depend on cortical depth and can be explained, at least in part, by the spatial gradient of delays in microvascular dilation, the fastest response being in the deep layers and the most delayed response in the capillary bed of layer I.

  1. LRP4 third β-propeller domain mutations cause novel congenital myasthenia by compromising agrin-mediated MuSK signaling in a position-specific manner.

    PubMed

    Ohkawara, Bisei; Cabrera-Serrano, Macarena; Nakata, Tomohiko; Milone, Margherita; Asai, Nobuyuki; Ito, Kenyu; Ito, Mikako; Masuda, Akio; Ito, Yasutomo; Engel, Andrew G; Ohno, Kinji

    2014-04-01

    Congenital myasthenic syndromes (CMS) are heterogeneous disorders in which the safety margin of neuromuscular transmission is compromised by one or more specific mechanisms. Using Sanger and exome sequencing in a CMS patient, we identified two heteroallelic mutations, p.Glu1233Lys and p.Arg1277His, in LRP4 coding for the postsynaptic low-density lipoprotein receptor-related protein 4. LRP4, expressed on the surface of the postsynaptic membrane of the neuromuscular junction, is a receptor for neurally secreted agrin, and LRP4 bound by agrin activates MuSK. Activated MuSK in concert with Dok-7 stimulates rapsyn to concentrate and anchor AChR on the postsynaptic membrane and interacts with other proteins implicated in the assembly and maintenance of the neuromuscular junction. LRP4 also functions as an inhibitor of Wnt/beta-catenin signaling. The identified mutations in LRP4 are located at the edge of its 3rd beta-propeller domain and decrease binding affinity of LRP4 for both MuSK and agrin. Mutations in the LRP4 3rd beta-propeller domain were previously reported to impair Wnt signaling and cause bone diseases including Cenani-Lenz syndactyly syndrome and sclerosteosis-2. By analyzing naturally occurring and artificially introduced mutations in the LRP4 3rd beta-propeller domain, we show that the edge of the domain regulates the MuSK signaling whereas its central cavity governs Wnt signaling. We conclude that LRP4 is a new CMS disease gene and that the 3rd beta propeller domain of LRP4 mediates the two signaling pathways in a position-specific manner.

  2. Cell-type specific crosstalk between p38 MAPK and Rho signaling in lung micro- and macrovascular barrier dysfunction induced by Staphylococcus aureus-derived pathogens

    PubMed Central

    Wu, Tinghuai; Xing, Junjie; Birukova, Anna A.

    2014-01-01

    Lung inflammation and alterations in endothelial cell (EC) micro- and macro-vascular permeability are key events to development of acute lung injury (ALI). Using ECs derived from human pulmonary artery (HPAECs) and lung microvasculature (HLMVECs), we investigated interplay between p38 stress MAPK and Rho GTPase signaling in the inflammatory and hyperpermeability response. Both cell types were treated with Staphylococcus aureus-derived peptidoglycan (PepG) and lipoteichoic acid (LTA) with or without pretreatment with p38 MAPK or Rho kinase inhibitors. LTA and PepG markedly increased permeability in both pulmonary macrovascular and microvascular EC. Agonist-induced hyper-permeability was accompanied by cytoskeletal remodeling, disruption of cell-cell contacts, formation of paracellular gaps, and activation of p38 MAPK, NFκB, and Rho/Rho kinase signaling. In macrovascular ECs, pharmacological inhibition of Rho kinase with Y27632 significantly suppressed p38 MAP kinase cascade activation, while inhibition of p38 MAPK with SB203580 had no effect on Rho activation. In contrast, inhibition of p38 MAPK in microvascular ECs suppressed LTA/PepG-induced activation of Rho, while Rho inhibitor suppressed activation of p38 MAPK. Inhibition of either p38 MAPK or Rho kinase substantially attenuated activation of NFκB signaling. These results demonstrate cell type-specific differences in signaling induced by Staphylococcus aureus-derived pathogens in pulmonary endothelium. Thus, although Gram-positive bacterial compounds caused barrier dysfunction in both EC types, it was induced by different pattern of crosstalk between Rho, p38 MAPK, and NFκB signaling. These observations may have important implications in defining microvasculature-specific therapeutic strategies aimed at the treatment of sepsis and acute lung injury induced by Gram-positive bacterial pathogens. PMID:23571093

  3. LRP4 third β-propeller domain mutations cause novel congenital myasthenia by compromising agrin-mediated MuSK signaling in a position-specific manner

    PubMed Central

    Ohkawara, Bisei; Cabrera-Serrano, Macarena; Nakata, Tomohiko; Milone, Margherita; Asai, Nobuyuki; Ito, Kenyu; Ito, Mikako; Masuda, Akio; Ito, Yasutomo; Engel, Andrew G.; Ohno, Kinji

    2014-01-01

    Congenital myasthenic syndromes (CMS) are heterogeneous disorders in which the safety margin of neuromuscular transmission is compromised by one or more specific mechanisms. Using Sanger and exome sequencing in a CMS patient, we identified two heteroallelic mutations, p.Glu1233Lys and p.Arg1277His, in LRP4 coding for the postsynaptic low-density lipoprotein receptor-related protein 4. LRP4, expressed on the surface of the postsynaptic membrane of the neuromuscular junction, is a receptor for neurally secreted agrin, and LRP4 bound by agrin activates MuSK. Activated MuSK in concert with Dok-7 stimulates rapsyn to concentrate and anchor AChR on the postsynaptic membrane and interacts with other proteins implicated in the assembly and maintenance of the neuromuscular junction. LRP4 also functions as an inhibitor of Wnt/beta-catenin signaling. The identified mutations in LRP4 are located at the edge of its 3rd beta-propeller domain and decrease binding affinity of LRP4 for both MuSK and agrin. Mutations in the LRP4 3rd beta-propeller domain were previously reported to impair Wnt signaling and cause bone diseases including Cenani–Lenz syndactyly syndrome and sclerosteosis-2. By analyzing naturally occurring and artificially introduced mutations in the LRP4 3rd beta-propeller domain, we show that the edge of the domain regulates the MuSK signaling whereas its central cavity governs Wnt signaling. We conclude that LRP4 is a new CMS disease gene and that the 3rd beta propeller domain of LRP4 mediates the two signaling pathways in a position-specific manner. PMID:24234652

  4. Effective signal-on photoelectrochemical immunoassay of subgroup J avian leukosis virus based on Bi2S3 nanorods as photosensitizer and in situ generated ascorbic acid for electron donating.

    PubMed

    Sun, Bing; Qiao, Fengmin; Chen, Lijian; Zhao, Zhen; Yin, Huanshun; Ai, Shiyun

    2014-04-15

    A universal and effective photoelectrochemical (PEC) immunosensing device was fabricated on an indium tin oxide (ITO) electrode for sensitive and specific detection of subgroup J of avian leukosis virus (ALVs-J) based on a signal-on strategy. Bismuth sulfide (Bi2S3) nanorods, with good morphology, high crystallinity and differentiated PEC properties, were selected as the photoelectrochemical species and synthesized by a facile hydrothermal method. On the basis of alkaline phosphatase catalytic chemistry to in situ produce ascorbic acid for electron donating, an enhanced photocurrent was obtained. Due to the dependence of the photocurrent signal on the concentration of generated electron donor, an exquisite immunosandwich protocol was successfully constructed for PEC detection of ALVs-J with a linear range from 10(2.14) to 10(3.65) TCID50/mL. The detection limit was 10(2.08) TCID50/mL (S/N=3), and high stability and specificity were obtained. The strategy provides a fast and sensitive method for ALVs-J analysis and opens a general format for future development of PEC immunoanalysis.

  5. Composite selection signals can localize the trait specific genomic regions in multi-breed populations of cattle and sheep

    PubMed Central

    2014-01-01

    Background Discerning the traits evolving under neutral conditions from those traits evolving rapidly because of various selection pressures is a great challenge. We propose a new method, composite selection signals (CSS), which unifies the multiple pieces of selection evidence from the rank distribution of its diverse constituent tests. The extreme CSS scores capture highly differentiated loci and underlying common variants hauling excess haplotype homozygosity in the samples of a target population. Results The data on high-density genotypes were analyzed for evidence of an association with either polledness or double muscling in various cohorts of cattle and sheep. In cattle, extreme CSS scores were found in the candidate regions on autosome BTA-1 and BTA-2, flanking the POLL locus and MSTN gene, for polledness and double muscling, respectively. In sheep, the regions with extreme scores were localized on autosome OAR-2 harbouring the MSTN gene for double muscling and on OAR-10 harbouring the RXFP2 gene for polledness. In comparison to the constituent tests, there was a partial agreement between the signals at the four candidate loci; however, they consistently identified additional genomic regions harbouring no known genes. Persuasively, our list of all the additional significant CSS regions contains genes that have been successfully implicated to secondary phenotypic diversity among several subpopulations in our data. For example, the method identified a strong selection signature for stature in cattle capturing selective sweeps harbouring UQCC-GDF5 and PLAG1-CHCHD7 gene regions on BTA-13 and BTA-14, respectively. Both gene pairs have been previously associated with height in humans, while PLAG1-CHCHD7 has also been reported for stature in cattle. In the additional analysis, CSS identified significant regions harbouring multiple genes for various traits under selection in European cattle including polledness, adaptation, metabolism, growth rate, stature

  6. Hemogenic endothelial cell specification requires c-kit, notch signaling, and p27-mediated cell-cycle control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Delineating the mechanism or mechanisms that regulate the specification of hemogenic endothelial cells from primordial endothelium is critical for optimizing their derivation from human stem cells for clinical therapies. We previously determined that retinoic acid (RA) is required for hemogenic spec...

  7. Religion and Action Control: Faith-Specific Modulation of the Simon Effect but Not Stop-Signal Performance

    ERIC Educational Resources Information Center

    Hommel, Bernhard; Colzato, Lorenza S.; Scorolli, Claudia; Borghi, Anna M.; van den Wildenberg, Wery P. M.

    2011-01-01

    Previous findings suggest that religion has a specific impact on attentional processes. Here we show that religion also affects action control. Experiment 1 compared Dutch Calvinists and Dutch atheists, matched for age, sex, intelligence, education, and cultural and socio-economic background, and Experiment 2 compared Italian Catholics with…

  8. Application of phosphorylation site-specific antibodies to measure nuclear receptor signaling: characterization of novel phosphoantibodies for estrogen receptor α

    PubMed Central

    Al-Dhaheri, Mariam H.; Rowan, Brian G.

    2006-01-01

    An understanding of posttranslational events in nuclear receptor signaling