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Sample records for rapid conformational activation

  1. Characterizing rapid, activity-linked conformational transitions in proteins via sub-second hydrogen deuterium exchange mass spectrometry.

    Science.gov (United States)

    Resetca, Diana; Wilson, Derek J

    2013-11-01

    This review outlines the application of time-resolved electrospray ionization mass spectrometry (TRESI-MS) and hydrogen-deuterium exchange (HDX) to study rapid, activity-linked conformational transitions in proteins. The method is implemented on a microfluidic chip which incorporates all sample-handling steps required for a 'bottom-up' HDX workflow: a capillary mixer for sub-second HDX labeling, a static mixer for HDX quenching, a microreactor for rapid protein digestion, and on-chip electrospray. By combining short HDX labeling pulses with rapid digestion, this approach provides a detailed characterization of the structural transitions that occur during protein folding, ligand binding, post-translational modification and catalytic turnover in enzymes. This broad spectrum of applications in areas largely inaccessible to conventional techniques means that microfluidics-enabled TRESI-MS/HDX is a unique and powerful approach for investigating the dynamic basis of protein function. © 2013 FEBS.

  2. SIMS: a hybrid method for rapid conformational analysis.

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    Bryant Gipson

    Full Text Available Proteins are at the root of many biological functions, often performing complex tasks as the result of large changes in their structure. Describing the exact details of these conformational changes, however, remains a central challenge for computational biology due the enormous computational requirements of the problem. This has engendered the development of a rich variety of useful methods designed to answer specific questions at different levels of spatial, temporal, and energetic resolution. These methods fall largely into two classes: physically accurate, but computationally demanding methods and fast, approximate methods. We introduce here a new hybrid modeling tool, the Structured Intuitive Move Selector (sims, designed to bridge the divide between these two classes, while allowing the benefits of both to be seamlessly integrated into a single framework. This is achieved by applying a modern motion planning algorithm, borrowed from the field of robotics, in tandem with a well-established protein modeling library. sims can combine precise energy calculations with approximate or specialized conformational sampling routines to produce rapid, yet accurate, analysis of the large-scale conformational variability of protein systems. Several key advancements are shown, including the abstract use of generically defined moves (conformational sampling methods and an expansive probabilistic conformational exploration. We present three example problems that sims is applied to and demonstrate a rapid solution for each. These include the automatic determination of "active" residues for the hinge-based system Cyanovirin-N, exploring conformational changes involving long-range coordinated motion between non-sequential residues in Ribose-Binding Protein, and the rapid discovery of a transient conformational state of Maltose-Binding Protein, previously only determined by Molecular Dynamics. For all cases we provide energetic validations using well

  3. Rapid Active Sampling Package

    Science.gov (United States)

    Peters, Gregory

    2010-01-01

    A field-deployable, battery-powered Rapid Active Sampling Package (RASP), originally designed for sampling strong materials during lunar and planetary missions, shows strong utility for terrestrial geological use. The technology is proving to be simple and effective for sampling and processing materials of strength. Although this originally was intended for planetary and lunar applications, the RASP is very useful as a powered hand tool for geologists and the mining industry to quickly sample and process rocks in the field on Earth. The RASP allows geologists to surgically acquire samples of rock for later laboratory analysis. This tool, roughly the size of a wrench, allows the user to cut away swaths of weathering rinds, revealing pristine rock surfaces for observation and subsequent sampling with the same tool. RASPing deeper (.3.5 cm) exposes single rock strata in-situ. Where a geologist fs hammer can only expose unweathered layers of rock, the RASP can do the same, and then has the added ability to capture and process samples into powder with particle sizes less than 150 microns, making it easier for XRD/XRF (x-ray diffraction/x-ray fluorescence). The tool uses a rotating rasp bit (or two counter-rotating bits) that resides inside or above the catch container. The container has an open slot to allow the bit to extend outside the container and to allow cuttings to enter and be caught. When the slot and rasp bit are in contact with a substrate, the bit is plunged into it in a matter of seconds to reach pristine rock. A user in the field may sample a rock multiple times at multiple depths in minutes, instead of having to cut out huge, heavy rock samples for transport back to a lab for analysis. Because of the speed and accuracy of the RASP, hundreds of samples can be taken in one day. RASP-acquired samples are small and easily carried. A user can characterize more area in less time than by using conventional methods. The field-deployable RASP used a Ni

  4. A Rapid Analysis of Variations in Conformational Behavior during Dihydrofolate Reductase Catalysis.

    Science.gov (United States)

    Hughes, Robert L; Johnson, Luke A; Behiry, Enas M; Loveridge, E Joel; Allemann, Rudolf K

    2017-04-18

    Protein flexibility is central to enzyme catalysis, yet it remains challenging both to predict conformational behavior on the basis of analysis of amino acid sequence and protein structure and to provide the necessary breadth of experimental support to any such predictions. Here a generic and rapid procedure for identifying conformational changes during dihydrofolate reductase (DHFR) catalysis is described. Using DHFR from Escherichia coli (EcDHFR), selective side-chain 13 C labeling of methionine and tryptophan residues is shown to be sufficient to detect the closed-to-occluded conformational transition that follows the chemical step in the catalytic cycle, with clear chemical shift perturbations found for both methionine methyl and tryptophan indole groups. In contrast, no such perturbations are seen for the DHFR from the psychrophile Moritella profunda, where the equivalent conformational change is absent. Like EcDHFR, Salmonella enterica DHFR shows experimental evidence of a large-scale conformational change following hydride transfer that relies on conservation of a key hydrogen bonding interaction between the M20 and GH loops, directly comparable to the closed-to-occluded conformational change observed in EcDHFR. For the hyperthermophile Thermotoga maritima, no chemical shift perturbations were observed, suggesting that no major conformational change occurs during the catalytic cycle. In spite of their conserved tertiary structures, DHFRs display variations in conformational sampling that occurs concurrently with catalysis.

  5. Substrate activation and conformational dynamics of guanosine 5'-monophosphate synthetase.

    Science.gov (United States)

    Oliver, Justin C; Linger, Rebecca S; Chittur, Sridar V; Davisson, V Jo

    2013-08-06

    Glutamine amidotransferases catalyze the amination of a wide range of molecules using the amide nitrogen of glutamine. The family provides numerous examples for study of multi-active-site regulation and interdomain communication in proteins. Guanosine 5'-monophosphate synthetase (GMPS) is one of three glutamine amidotransferases in de novo purine biosynthesis and is responsible for the last step in the guanosine branch of the pathway, the amination of xanthosine 5'-monophosphate (XMP). In several amidotransferases, the intramolecular path of ammonia from glutamine to substrate is understood; however, the crystal structure of GMPS only hinted at the details of such transfer. Rapid kinetics studies provide insight into the mechanism of the substrate-induced changes in this complex enzyme. Rapid mixing of GMPS with substrates also manifests absorbance changes that report on the kinetics of formation of a reactive intermediate as well as steps in the process of rapid transfer of ammonia to this intermediate. Isolation and use of the adenylylated nucleotide intermediate allowed the study of the amido transfer reaction distinct from the ATP-dependent reaction. Changes in intrinsic tryptophan fluorescence upon mixing of enzyme with XMP suggest a conformational change upon substrate binding, likely the ordering of a highly conserved loop in addition to global domain motions. In the GMPS reaction, all forward rates before product release appear to be faster than steady-state turnover, implying that release is likely rate-limiting. These studies establish the functional role of a substrate-induced conformational change in the GMPS catalytic cycle and provide a kinetic context for the formation of an ammonia channel linking the distinct active sites.

  6. Direct synthesis and characterization of optically transparent conformal zinc oxide nanocrystalline thin films by rapid thermal plasma CVD

    National Research Council Canada - National Science Library

    Pedersen, Joachim D; Esposito, Heather J; Teh, Kwok Siong

    2011-01-01

    We report a rapid, self-catalyzed, solid precursor-based thermal plasma chemical vapor deposition process for depositing a conformal, nonporous, and optically transparent nanocrystalline ZnO thin film at 130 Torr (0.17 atm...

  7. Reconstituted IMPDH polymers accommodate both catalytically active and inactive conformations.

    Science.gov (United States)

    Anthony, Sajitha A; Burrell, Anika L; Johnson, Matthew C; Duong-Ly, Krisna C; Kuo, Yin-Ming; Simonet, Jacqueline C; Michener, Peter; Andrews, Andrew; Kollman, Justin M; Peterson, Jeffrey R

    2017-08-09

    Several metabolic enzymes undergo reversible polymerization into macromolecular assemblies. The function of these assemblies is often unclear but in some cases they regulate enzyme activity and metabolic homeostasis. The guanine nucleotide biosynthetic enzyme inosine monophosphate dehydrogenase (IMPDH) forms octamers that polymerize into helical chains. In mammalian cells, IMPDH filaments can associate into micron-length assemblies. Polymerization and enzyme activity are regulated in part by binding of purine nucleotides to an allosteric regulatory domain. ATP promotes octamer polymerization, whereas GTP promotes a compact, inactive conformation whose ability to polymerize is unknown. Also unclear is whether polymerization directly alters IMPDH catalytic activity. To address this, we identified point mutants of human IMPDH2 that either prevent or promote polymerization. Unexpectedly, we found that polymerized and non-assembled forms of recombinant IMPDH have comparable catalytic activity, substrate affinity, and GTP sensitivity and validated this finding in cells. Electron microscopy revealed that substrates and allosteric nucleotides shift the equilibrium between active and inactive conformations in both the octamer and the filament. Unlike other metabolic filaments, which selectively stabilize active or inactive conformations, recombinant IMPDH filaments accommodate multiple states. These conformational states are finely tuned by substrate availability and purine balance, while polymerization may allow cooperative transitions between states. © 2017 by The American Society for Cell Biology.

  8. Conformational preferences underlying reduced activity of a thermophilic ribonuclease H.

    Science.gov (United States)

    Stafford, Kate A; Trbovic, Nikola; Butterwick, Joel A; Abel, Robert; Friesner, Richard A; Palmer, Arthur G

    2015-02-27

    The conformational basis for reduced activity of the thermophilic ribonuclease HI enzyme from Thermus thermophilus, compared to its mesophilic homolog from Escherichia coli, is elucidated using a combination of NMR spectroscopy and molecular dynamics (MD) simulations. Explicit-solvent all-atom MD simulations of the two wild-type proteins and an E. coli mutant in which a glycine residue is inserted after position 80 to mimic the T. thermophilus protein reproduce the differences in conformational dynamics determined from (15)N spin-relaxation NMR spectroscopy of three loop regions that surround the active site and contain functionally important residues: the glycine-rich region, the handle region, and the β5/αE loop. Examination of the MD trajectories indicates that the thermophilic protein samples conformations productive for substrate binding and activity less frequently than the mesophilic enzyme, although these differences may manifest as either increased or decreased relative flexibility of the different regions. Additional MD simulations indicate that mutations increasing activity of the T. thermophilus enzyme at mesophilic temperatures do so by reconfiguring the local environments of the mutated sites to more closely resemble active conformations. Taken together, the results show that both locally increased and decreased flexibility contribute to an overall reduction in activity of T. thermophilus ribonuclease H compared to its mesophilic E. coli homolog. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Conformational transition pathway in the activation process of allosteric glucokinase.

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    Min Huang

    Full Text Available Glucokinase (GK is a glycolytic enzyme that plays an important role in regulating blood glucose level, thus acting as a potentially attractive target for drug discovery in the treatment of diabetes of the young type 2 and persistent hyperinsulinemic hypoglycemia of infancy. To characterize the activation mechanism of GK from the super-open state (inactive state to the closed state (active state, a series of conventional molecular dynamics (MD and targeted MD (TMD simulations were performed on this enzyme. Conventional MD simulation showed a specific conformational ensemble of GK when the enzyme is inactive. Seven TMD simulations depicted a reliably conformational transition pathway of GK from the inactive state to the active state, and the components important to the conformational change of GK were identified by analyzing the detailed structures of the TMD trajectories. In combination with the inactivation process, our findings showed that the whole conformational pathway for the activation-inactivation-activation of GK is a one-direction circulation, and the active state is less stable than the inactive state in the circulation. Additionally, glucose was demonstrated to gradually modulate its binding pose with the help of residues in the large domain and connecting region of GK during the activation process. Furthermore, the obtained energy barriers were used to explain the preexisting equilibrium and the slow binding kinetic process of the substrate by GK. The simulated results are in accordance with the recent findings from the mutagenesis experiments and kinetic analyses. Our observations reveal a complicated conformational process in the allosteric protein, resulting in new knowledge about the delicate mechanisms for allosteric biological macromolecules that will be useful in drug design for targeting allosteric proteins.

  10. Cancer associated E17K mutation causes rapid conformational drift in AKT1 pleckstrin homology (PH domain.

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    Ambuj Kumar

    Full Text Available BACKGROUND: AKT1 (v-akt murine thymoma viral oncogene homologue 1 kinase is one of the most frequently activated proliferated and survival pathway of cancer. Recently it has been shown that E17K mutation in the Pleckstrin Homology (PH domain of AKT1 protein leads to cancer by amplifying the phosphorylation and membrane localization of protein. The mutant has shown resistance to AKT1/2 inhibitor VIII drug molecule. In this study we have demonstrated the detailed structural and molecular consequences associated with the activity regulation of mutant protein. METHODS: The docking score exhibited significant loss in the interaction affinity to AKT1/2 inhibitor VIII drug molecule. Furthermore, the molecular dynamics simulation studies presented an evidence of rapid conformational drift observed in mutant structure. RESULTS: There was no stability loss in mutant as compared to native structure and the major cation-π interactions were also shown to be retained. Moreover, the active residues involved in membrane localization of protein exhibited significant rise in NHbonds formation in mutant. The rise in NHbond formation in active residues accounts for the 4-fold increase in the membrane localization potential of protein. CONCLUSION: The overall result suggested that, although the mutation did not induce any stability loss in structure, the associated pathological consequences might have occurred due to the rapid conformational drifts observed in the mutant AKT1 PH domain. GENERAL SIGNIFICANCE: The methodology implemented and the results obtained in this work will facilitate in determining the core molecular mechanisms of cancer-associated mutations and in designing their potential drug inhibitors.

  11. Rapid RNA-ligand interaction analysis through high-information content conformational and stability landscapes

    Energy Technology Data Exchange (ETDEWEB)

    Baird, Nathan J. [National Inst. of Health (NIH), Bethesda, MD (United States); Inglese, James [National Inst. of Health (NIH), Bethesda, MD (United States); Ferré-D’Amaré, Adrian R. [National Inst. of Health (NIH), Bethesda, MD (United States)

    2015-12-07

    The structure and biological properties of RNAs are a function of changing cellular conditions, but comprehensive, simultaneous investigation of the effect of multiple interacting environmental variables is not easily achieved. We have developed an efficient, high-throughput method to characterize RNA structure and thermodynamic stability as a function of multiplexed solution conditions using Förster resonance energy transfer (FRET). In a single FRET experiment using conventional quantitative PCR instrumentation, 19,400 conditions of MgCl2, ligand and temperature are analysed to generate detailed empirical conformational and stability landscapes of the cyclic diguanylate (c-di-GMP) riboswitch. This method allows rapid comparison of RNA structure modulation by cognate and non-cognate ligands. Landscape analysis reveals that kanamycin B stabilizes a non-native, idiosyncratic conformation of the riboswitch that inhibits c-di-GMP binding. Our research demonstrates that allosteric control of folding, rather than direct competition with cognate effectors, is a viable approach for pharmacologically targeting riboswitches and other structured RNA molecules.

  12. Identifying multiple active conformations in the G protein-coupled receptor activation landscape using computational methods.

    Science.gov (United States)

    Dong, Sijia S; Goddard, William A; Abrol, Ravinder

    2017-01-01

    G protein-coupled receptors (GPCRs) are membrane proteins critical in cellular signaling, making them important targets for therapeutics. The activation of GPCRs is central to their function, requiring multiple conformations of the GPCRs in their activation landscape. To enable rational design of GPCR-targeting drugs, it is essential to obtain the ensemble of atomistic structures of GPCRs along their activation pathways. This is most challenging for structure determination experiments, making it valuable to develop reliable computational structure prediction methods. In particular, since the active-state conformations are higher in energy (less stable) than inactive-state conformations, they are difficult to stabilize. In addition, the computational methods are generally biased toward lowest energy structures by design and miss these high energy but functionally important conformations. To address this problem, we have developed a computationally efficient ActiveGEnSeMBLE method that systematically predicts multiple conformations that are likely in the GPCR activation landscape, including multiple active- and inactive-state conformations. ActiveGEnSeMBLE starts with a systematic coarse grid sampling of helix tilts/rotations (~13 trillion transmembrane domain conformations) and identifies multiple potential active-state energy wells, using the TM3-TM6 intracellular distance as a surrogate activation coordinate. These energy wells are then sampled locally using a finer grid in conformational space to find a locally minimized conformation in each energy well, which can be further relaxed using molecular dynamics (MD) simulations. This method, combining homology modeling, hierarchical complete conformational sampling, and nanosecond scale MD, provides one of the very few computational methods that predict multiple candidates for active-state conformations and is one of the most computationally affordable. © 2017 Elsevier Inc. All rights reserved.

  13. Conformational equilibria and intrinsic affinities define integrin activation.

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    Li, Jing; Su, Yang; Xia, Wei; Qin, Yan; Humphries, Martin J; Vestweber, Dietmar; Cabañas, Carlos; Lu, Chafen; Springer, Timothy A

    2017-03-01

    We show that the three conformational states of integrin α5β1 have discrete free energies and define activation by measuring intrinsic affinities for ligand of each state and the equilibria linking them. The 5,000-fold higher affinity of the extended-open state than the bent-closed and extended-closed states demonstrates profound regulation of affinity. Free energy requirements for activation are defined with protein fragments and intact α5β1 On the surface of K562 cells, α5β1 is 99.8% bent-closed. Stabilization of the bent conformation by integrin transmembrane and cytoplasmic domains must be overcome by cellular energy input to stabilize extension. Following extension, headpiece opening is energetically favored. N-glycans and leg domains in each subunit that connect the ligand-binding head to the membrane repel or crowd one another and regulate conformational equilibria in favor of headpiece opening. The results suggest new principles for regulating signaling in the large class of receptors built from extracellular domains in tandem with single-span transmembrane domains. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

  14. Direct synthesis and characterization of optically transparent conformal zinc oxide nanocrystalline thin films by rapid thermal plasma CVD

    OpenAIRE

    Pedersen, Joachim D; Esposito, Heather J; Teh, Kwok Siong

    2011-01-01

    We report a rapid, self-catalyzed, solid precursor-based thermal plasma chemical vapor deposition process for depositing a conformal, nonporous, and optically transparent nanocrystalline ZnO thin film at 130 Torr (0.17 atm). Pure solid zinc is inductively heated and melted, followed by ionization by thermal induction argon/oxygen plasma to produce conformal, nonporous nanocrystalline ZnO films at a growth rate of up to 50 nm/min on amorphous and crystalline substrates including Si (100), fuse...

  15. Interrogating the activities of conformational deformed enzyme by single-molecule fluorescence-magnetic tweezers microscopy

    Science.gov (United States)

    Guo, Qing; He, Yufan; Lu, H. Peter

    2015-01-01

    Characterizing the impact of fluctuating enzyme conformation on enzymatic activity is critical in understanding the structure–function relationship and enzymatic reaction dynamics. Different from studying enzyme conformations under a denaturing condition, it is highly informative to manipulate the conformation of an enzyme under an enzymatic reaction condition while monitoring the real-time enzymatic activity changes simultaneously. By perturbing conformation of horseradish peroxidase (HRP) molecules using our home-developed single-molecule total internal reflection magnetic tweezers, we successfully manipulated the enzymatic conformation and probed the enzymatic activity changes of HRP in a catalyzed H2O2–amplex red reaction. We also observed a significant tolerance of the enzyme activity to the enzyme conformational perturbation. Our results provide a further understanding of the relation between enzyme behavior and enzymatic conformational fluctuation, enzyme–substrate interactions, enzyme–substrate active complex formation, and protein folding–binding interactions. PMID:26512103

  16. Protein Conformational Gating of Enzymatic Activity in Xanthine Oxidoreductase

    Energy Technology Data Exchange (ETDEWEB)

    Ishikita, Hiroshi; Eger, Bryan T.; Okamoto, Ken; Nishino, Takeshi; Pai, Emil F. (Toronto); (Kyoto)

    2012-05-24

    In mammals, xanthine oxidoreductase can exist as xanthine dehydrogenase (XDH) and xanthine oxidase (XO). The two enzymes possess common redox active cofactors, which form an electron transfer (ET) pathway terminated by a flavin cofactor. In spite of identical protein primary structures, the redox potential difference between XDH and XO for the flavin semiquinone/hydroquinone pair (E{sub sq/hq}) is {approx}170 mV, a striking difference. The former greatly prefers NAD{sup +} as ultimate substrate for ET from the iron-sulfur cluster FeS-II via flavin while the latter only accepts dioxygen. In XDH (without NAD{sup +}), however, the redox potential of the electron donor FeS-II is 180 mV higher than that for the acceptor flavin, yielding an energetically uphill ET. On the basis of new 1.65, 2.3, 1.9, and 2.2 {angstrom} resolution crystal structures for XDH, XO, the NAD{sup +}- and NADH-complexed XDH, E{sub sq/hq} were calculated to better understand how the enzyme activates an ET from FeS-II to flavin. The majority of the E{sub sq/hq} difference between XDH and XO originates from a conformational change in the loop at positions 423-433 near the flavin binding site, causing the differences in stability of the semiquinone state. There was no large conformational change observed in response to NAD{sup +} binding at XDH. Instead, the positive charge of the NAD{sup +} ring, deprotonation of Asp429, and capping of the bulk surface of the flavin by the NAD{sup +} molecule all contribute to altering E{sub sq/hq} upon NAD{sup +} binding to XDH.

  17. Protein conformational gating of enzymatic activity in xanthine oxidoreductase.

    Science.gov (United States)

    Ishikita, Hiroshi; Eger, Bryan T; Okamoto, Ken; Nishino, Takeshi; Pai, Emil F

    2012-01-18

    In mammals, xanthine oxidoreductase can exist as xanthine dehydrogenase (XDH) and xanthine oxidase (XO). The two enzymes possess common redox active cofactors, which form an electron transfer (ET) pathway terminated by a flavin cofactor. In spite of identical protein primary structures, the redox potential difference between XDH and XO for the flavin semiquinone/hydroquinone pair (E(sq/hq)) is ~170 mV, a striking difference. The former greatly prefers NAD(+) as ultimate substrate for ET from the iron-sulfur cluster FeS-II via flavin while the latter only accepts dioxygen. In XDH (without NAD(+)), however, the redox potential of the electron donor FeS-II is 180 mV higher than that for the acceptor flavin, yielding an energetically uphill ET. On the basis of new 1.65, 2.3, 1.9, and 2.2 Å resolution crystal structures for XDH, XO, the NAD(+)- and NADH-complexed XDH, E(sq/hq) were calculated to better understand how the enzyme activates an ET from FeS-II to flavin. The majority of the E(sq/hq) difference between XDH and XO originates from a conformational change in the loop at positions 423-433 near the flavin binding site, causing the differences in stability of the semiquinone state. There was no large conformational change observed in response to NAD(+) binding at XDH. Instead, the positive charge of the NAD(+) ring, deprotonation of Asp429, and capping of the bulk surface of the flavin by the NAD(+) molecule all contribute to altering E(sq/hq) upon NAD(+) binding to XDH. © 2011 American Chemical Society

  18. Differential active site loop conformations mediate promiscuous activities in the lactonase SsoPox.

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    Julien Hiblot

    Full Text Available Enzymes are proficient catalysts that enable fast rates of Michaelis-complex formation, the chemical step and products release. These different steps may require different conformational states of the active site that have distinct binding properties. Moreover, the conformational flexibility of the active site mediates alternative, promiscuous functions. Here we focused on the lactonase SsoPox from Sulfolobus solfataricus. SsoPox is a native lactonase endowed with promiscuous phosphotriesterase activity. We identified a position in the active site loop (W263 that governs its flexibility, and thereby affects the substrate specificity of the enzyme. We isolated two different sets of substitutions at position 263 that induce two distinct conformational sampling of the active loop and characterized the structural and kinetic effects of these substitutions. These sets of mutations selectively and distinctly mediate the improvement of the promiscuous phosphotriesterase and oxo-lactonase activities of SsoPox by increasing active-site loop flexibility. These observations corroborate the idea that conformational diversity governs enzymatic promiscuity and is a key feature of protein evolvability.

  19. Rapid fine conformational epitope mapping using comprehensive mutagenesis and deep sequencing.

    Science.gov (United States)

    Kowalsky, Caitlin A; Faber, Matthew S; Nath, Aritro; Dann, Hailey E; Kelly, Vince W; Liu, Li; Shanker, Purva; Wagner, Ellen K; Maynard, Jennifer A; Chan, Christina; Whitehead, Timothy A

    2015-10-30

    Knowledge of the fine location of neutralizing and non-neutralizing epitopes on human pathogens affords a better understanding of the structural basis of antibody efficacy, which will expedite rational design of vaccines, prophylactics, and therapeutics. However, full utilization of the wealth of information from single cell techniques and antibody repertoire sequencing awaits the development of a high throughput, inexpensive method to map the conformational epitopes for antibody-antigen interactions. Here we show such an approach that combines comprehensive mutagenesis, cell surface display, and DNA deep sequencing. We develop analytical equations to identify epitope positions and show the method effectiveness by mapping the fine epitope for different antibodies targeting TNF, pertussis toxin, and the cancer target TROP2. In all three cases, the experimentally determined conformational epitope was consistent with previous experimental datasets, confirming the reliability of the experimental pipeline. Once the comprehensive library is generated, fine conformational epitope maps can be prepared at a rate of four per day. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Evaluation of usefulness of single-strand conformation polymorphism method for rapid detection of rifampicin-resistant mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Tešić Jelena

    2004-01-01

    Full Text Available The aim was to evaluate the Single-Strand Conformation Polymorphism method as a potential tool for rapid detection of rifampicin-resistant strains by the use of 39 rifampicin-resistant Mycobacterium tuberculosis strains isolated in Serbia. SSCP analysis on acrylamide gel detected 56.4% of the rifampicin-resistant M. tuberculosis strains and showed the inability to detect one of the most frequent mutations, TCG®TTG mutation in codon 531 of the rpoB gene, which was shown by automated sequencing.

  1. Towards an Observation of Active Conformations in Asymmetric Catalysis: Interaction-Induced Conformational Preferences of a Chiral Thiourea Model Compound.

    Science.gov (United States)

    Kreienborg, Nora M; Pollok, Corina H; Merten, Christian

    2016-08-22

    The observation of the active species is the goal of most spectroscopic investigations on enantioselective organocatalysts in solution. Although NMR spectroscopy is widely applied, it has low sensitivity for conformational changes or the chiral nature of the interactions. In the present work, we exemplify the use of vibrational circular dichroism (VCD) spectroscopy for the characterization of a chiral thiourea model compound in nonpolar and polar solvents, as well as for a detailed analysis of its interaction with a model reactant. We discuss solvent-induced conformational changes of the thiourea, and provide evidence for an unexpected binding topology between the thiourea and an acetate anion. The results clearly showcase the possibilities offered by using VCD spectroscopy in the characterization of chiral organocatalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Multiple active site conformers in the carbon monoxide complexes of trematode hemoglobins.

    Science.gov (United States)

    Das, Tapan K; Dewilde, Sylvia; Friedman, Joel M; Moens, Luc; Rousseau, Denis L

    2006-04-28

    Sequence alignment of hemoglobins of the trematodes Paramphistomum epiclitum and Gastrothylax crumenifer with myoglobin suggests the presence of an unusual active site structure in which two tyrosine residues occupy the E7 and B10 helical positions. In the crystal structure of P. epiclitum hemoglobin, such an E7-B10 tyrosine pair at the putative helical positions has been observed, although the E7 Tyr is displaced toward CD region of the polypeptide. Resonance Raman data on both P. epiclitum and G. crumenifer hemoglobins show that interactions of heme-bound ligands with neighboring amino acid residues are unusual. Multiple conformers in the CO complex, termed the C, O, and N conformers, are observed. The conformers are separated by a large difference (approximately 60 cm(-1)) in the frequencies of their Fe-CO stretching modes. In the C conformer the Fe-CO stretching frequency is very high, 539 and 535 cm(-1), for the P. epiclitum and G. crumenifer hemoglobins, respectively. The Fe-CO stretching of the N conformer appears at an unusually low frequency, 479 and 476 cm(-1), respectively, for the two globins. A population of an O conformer is seen in both hemoglobins, at 496 and 492 cm(-1), respectively. The C conformer is stabilized by a strong polar interaction of the CO with the distal B10 tyrosine residue. The O conformer is similar to the ones typically seen in mutant myoglobins in which there are no strong interactions between the CO and residues in the distal pocket. The N conformer possesses an unusual configuration in which a negatively charged group, assigned as the oxygen atom of the B10 Tyr side chain, interacts with the CO. In this conformer, the B10 Tyr assumes an alternative conformation consistent with one of the conformers seen the crystal structure. Implications of the multiple configurations on the ligand kinetics are discussed.

  3. Distinct conformational changes in activated agonist-bound and agonist-free glycine receptor subunits

    DEFF Research Database (Denmark)

    Pless, Stephan Alexander; Lynch, Joseph W

    2009-01-01

    glycine activation but not during ivermectin activation. This prompted the hypothesis that this signal reports a glycine-mediated conformational change not essential for activation. We tested this by investigating whether the fluorescence signal depended on whether the fluorophore was attached...

  4. Discovery of a novel conformational equilibrium in urokinase-type plasminogen activator.

    Science.gov (United States)

    Kromann-Hansen, Tobias; Louise Lange, Eva; Peter Sørensen, Hans; Hassanzadeh-Ghassabeh, Gholamreza; Huang, Mingdong; Jensen, Jan K; Muyldermans, Serge; Declerck, Paul J; Komives, Elizabeth A; Andreasen, Peter A

    2017-06-13

    Although trypsin-like serine proteases have flexible surface-exposed loops and are known to adopt higher and lower activity conformations, structural determinants for the different conformations have remained largely obscure. The trypsin-like serine protease, urokinase-type plasminogen activator (uPA), is central in tissue remodeling processes and also strongly implicated in tumor metastasis. We solved five X-ray crystal structures of murine uPA (muPA) in the absence and presence of allosteric molecules and/or substrate-like molecules. The structure of unbound muPA revealed an unsuspected non-chymotrypsin-like protease conformation in which two β-strands in the core of the protease domain undergoes a major antiparallel-to-parallel conformational transition. We next isolated two anti-muPA nanobodies; an active-site binding nanobody and an allosteric nanobody. Crystal structures of the muPA:nanobody complexes and hydrogen-deuterium exchange mass spectrometry revealed molecular insights about molecular factors controlling the antiparallel-to-parallel equilibrium in muPA. Together with muPA activity assays, the data provide valuable insights into regulatory mechanisms and conformational flexibility of uPA and trypsin-like serine proteases in general.

  5. Decay of an active GPCR: Conformational dynamics govern agonist rebinding and persistence of an active, yet empty, receptor state.

    Science.gov (United States)

    Schafer, Christopher T; Fay, Jonathan F; Janz, Jay M; Farrens, David L

    2016-10-18

    Here, we describe two insights into the role of receptor conformational dynamics during agonist release (all-trans retinal, ATR) from the visual G protein-coupled receptor (GPCR) rhodopsin. First, we show that, after light activation, ATR can continually release and rebind to any receptor remaining in an active-like conformation. As with other GPCRs, we observe that this equilibrium can be shifted by either promoting the active-like population or increasing the agonist concentration. Second, we find that during decay of the signaling state an active-like, yet empty, receptor conformation can transiently persist after retinal release, before the receptor ultimately collapses into an inactive conformation. The latter conclusion is based on time-resolved, site-directed fluorescence labeling experiments that show a small, but reproducible, lag between the retinal leaving the protein and return of transmembrane helix 6 (TM6) to the inactive conformation, as determined from tryptophan-induced quenching studies. Accelerating Schiff base hydrolysis and subsequent ATR dissociation, either by addition of hydroxylamine or introduction of mutations, further increased the time lag between ATR release and TM6 movement. These observations show that rhodopsin can bind its agonist in equilibrium like a traditional GPCR, provide evidence that an active GPCR conformation can persist even after agonist release, and raise the possibility of targeting this key photoreceptor protein by traditional pharmaceutical-based treatments.

  6. Obedience, Conformity, and Social Roles: Active Learning in a Large Introductory Psychology Class.

    Science.gov (United States)

    Bleske-Rechek, April L.

    2001-01-01

    Focuses on an activity used in an introductory psychology course that enabled students (n=65) to comprehend the concepts of obedience, conformity, and social roles in the area of social psychology. Explains that the students found the activity to be helpful in understanding the role of social influence. (CMK)

  7. Aggregated, conformationally changed fibrinogen exposes the stimulating sites for t-PA-catalysed plasminogen activation

    NARCIS (Netherlands)

    Haddeland, U.; Sletten, K.; Bennick, A.; Nieuwenhuizen, W.; Brosstad, F.

    1996-01-01

    The present paper shows that conformationally changed fibrinogen can expose the sites Aα-(148-160) and γ-(312-324) involved in stimulation of the tissue-type plasminogen activator (t-PA)-catalysed plasminogen activation. The exposure of the stimulating sites was determined by ELISA using mABs

  8. Improving active Mealy machine learning for protocol conformance testing

    NARCIS (Netherlands)

    Aarts, F.; Kuppens, H.; Tretmans, J.; Vaandrager, F.; Verwer, S.

    2014-01-01

    Using a well-known industrial case study from the verification literature, the bounded retransmission protocol, we show how active learning can be used to establish the correctness of protocol implementation I relative to a given reference implementation R. Using active learning, we learn a model M

  9. Relevance of allosteric conformations and homocarnosine concentration on carnosinase activity

    NARCIS (Netherlands)

    Peters, V.; Kebbewar, M.; Jansen, E.E.W.; Jakobs, C.; Riedl, E.; Koeppel, H.; Frey, D.; Adelmann, K.; Klingbeil, K.; Mack, M; Hoffmann, G.F.; Janssen, B.; Zschocke, J.; Yard, B.A.

    2010-01-01

    Activity of carnosinase (CN1), the only dipeptidase with substrate specificity for carnosine or homocarnosine, varies greatly between individuals but increases clearly and significantly with age. Surprisingly, the lower CN1 activity in children is not reflected by differences in CN1 protein

  10. Direct synthesis and characterization of optically transparent conformal zinc oxide nanocrystalline thin films by rapid thermal plasma CVD

    Science.gov (United States)

    Pedersen, Joachim D.; Esposito, Heather J.; Teh, Kwok Siong

    2011-10-01

    We report a rapid, self-catalyzed, solid precursor-based thermal plasma chemical vapor deposition process for depositing a conformal, nonporous, and optically transparent nanocrystalline ZnO thin film at 130 Torr (0.17 atm). Pure solid zinc is inductively heated and melted, followed by ionization by thermal induction argon/oxygen plasma to produce conformal, nonporous nanocrystalline ZnO films at a growth rate of up to 50 nm/min on amorphous and crystalline substrates including Si (100), fused quartz, glass, muscovite, c- and a-plane sapphire (Al2O3), gold, titanium, and polyimide. X-ray diffraction indicates the grains of as-deposited ZnO to be highly textured, with the fastest growth occurring along the c-axis. The individual grains are observed to be faceted by (103) planes which are the slowest growth planes. ZnO nanocrystalline films of nominal thicknesses of 200 nm are deposited at substrate temperatures of 330°C and 160°C on metal/ceramic substrates and polymer substrates, respectively. In addition, 20-nm- and 200-nm-thick films are also deposited on quartz substrates for optical characterization. At optical spectra above 375 nm, the measured optical transmittance of a 200-nm-thick ZnO film is greater than 80%, while that of a 20-nm-thick film is close to 100%. For a 200-nm-thick ZnO film with an average grain size of 100 nm, a four-point probe measurement shows electrical conductivity of up to 910 S/m. Annealing of 200-nm-thick ZnO films in 300 sccm pure argon at temperatures ranging from 750°C to 950°C (at homologous temperatures between 0.46 and 0.54) alters the textures and morphologies of the thin film. Based on scanning electron microscope images, higher annealing temperatures appear to restructure the ZnO nanocrystalline films to form nanorods of ZnO due to a combination of grain boundary diffusion and bulk diffusion. PACS: films and coatings, 81.15.-z; nanocrystalline materials, 81.07.Bc; II-VI semiconductors, 81.05.Dz.

  11. Phenolic Lipids Affect the Activity and Conformation of Acetylcholinesterase from Electrophorus electricus (Electric eel)

    Science.gov (United States)

    Stasiuk, Maria; Janiszewska, Alicja; Kozubek, Arkadiusz

    2014-01-01

    Phenolic lipids were isolated from rye grains, cashew nutshell liquid (CNSL) from Anacardium occidentale, and fruit bodies of Merrulius tremellosus, and their effects on the electric eel acetylcholinesterase activity and conformation were studied. The observed effect distinctly depended on the chemical structure of the phenolic lipids that were available for interaction with the enzyme. All of the tested compounds reduced the activity of acetylcholinesterase. The degree of inhibition varied, showing a correlation with changes in the conformation of the enzyme tested by the intrinsic fluorescence of the Trp residues of the protein. PMID:24787269

  12. Active site loop conformation regulates promiscuous activity in a lactonase from Geobacillus kaustophilus HTA426.

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    Full Text Available Enzyme promiscuity is a prerequisite for fast divergent evolution of biocatalysts. A phosphotriesterase-like lactonase (PLL from Geobacillus kaustophilus HTA426 (GkaP exhibits main lactonase and promiscuous phosphotriesterase activities. To understand its catalytic and evolutionary mechanisms, we investigated a "hot spot" in the active site by saturation mutagenesis as well as X-ray crystallographic analyses. We found that position 99 in the active site was involved in substrate discrimination. One mutant, Y99L, exhibited 11-fold improvement over wild-type in reactivity (kcat/Km toward the phosphotriesterase substrate ethyl-paraoxon, but showed 15-fold decrease toward the lactonase substrate δ-decanolactone, resulting in a 157-fold inversion of the substrate specificity. Structural analysis of Y99L revealed that the mutation causes a ∼6.6 Å outward shift of adjacent loop 7, which may cause increased flexibility of the active site and facilitate accommodation and/or catalysis of organophosphate substrate. This study provides for the PLL family an example of how the evolutionary route from promiscuity to specificity can derive from very few mutations, which promotes alteration in the conformational adjustment of the active site loops, in turn draws the capacity of substrate binding and activity.

  13. Four Specific Hapten Conformations Dominating Antibody Specificity: Quantitative Structure-Activity Relationship Analysis for Quinolone Immunoassay.

    Science.gov (United States)

    Chen, Jiahong; Wang, Lanteng; Lu, Lanlan; Shen, Xing; Huang, Xin-An; Liu, Yingju; Sun, Xiulan; Wang, Zhanhui; Eremin, Sergei Alexandrovich; Sun, Yuanming; Xu, Zhenlin; Lei, Hongtao

    2017-06-20

    Antibody-based immunoassay methods have been important tools for monitoring drug residues in animal foods. However, because of limited knowledge about the quantitative structure-activity relationships between a hapten and its resultant antibody specificity, antibody production with the desired specificity is still a huge challenge. In this study, the three-dimensional quantitative structure-activity relationship (3D QSAR) was analyzed in accordance with the cross-reactivity of quinolone drugs reacting with the antibody raised by pipemidic acid as the immunizing hapten and compared with the reported cross-reactivity data and their hapten structures. It was found that the specificity of a quinolone antibody was strongly related to the conformation of the hapten used and that hapten conformations shaped like the letters "I", "P", and "Φ" were essential for the desired high specificity with low cross-reactivity, but that the hapten conformation shaped like the letter "Y" led to an antibody with broad specificity and high cross-reactivity. Almost all of the antibodies against quinolones could result from these four hapten conformations. It was first found that the concrete conformations dominated the specificity of the antibody to quinolone, which will be of significance for the accurate hapten design, predictable antibody specificity, and better understanding the recognition mechanism between haptens and the antibodies for immunoassays.

  14. Pollutant-induced modulation in conformation and β-lactamase activity of human serum albumin.

    Directory of Open Access Journals (Sweden)

    Ejaz Ahmad

    Full Text Available Structural changes in human serum albumin (HSA induced by the pollutants 1-naphthol, 2-naphthol and 8-quinolinol were analyzed by circular dichroism, fluorescence spectroscopy and dynamic light scattering. The alteration in protein conformational stability was determined by helical content induction (from 55 to 75% upon protein-pollutant interactions. Domain plasticity is responsible for the temperature-mediated unfolding of HSA. These findings were compared to HSA-hydrolase activity. We found that though HSA is a monomeric protein, it shows heterotropic allostericity for β-lactamase activity in the presence of pollutants, which act as K- and V-type non-essential activators. Pollutants cause conformational changes and catalytic modifications of the protein (increase in β-lactamase activity from 100 to 200%. HSA-pollutant interactions mediate other protein-ligand interactions, such as HSA-nitrocefin. Therefore, this protein can exist in different conformations with different catalytic properties depending on activator binding. This is the first report to demonstrate the catalytic allostericity of HSA through a mechanistic approach. We also show a correlation with non-microbial drug resistance as HSA is capable of self-hydrolysis of β-lactam drugs, which is further potentiated by pollutants due to conformational changes in HSA.

  15. Workers’ Conformism

    Directory of Open Access Journals (Sweden)

    Nikolay Ivantchev

    2013-10-01

    Full Text Available Conformism was studied among 46 workers with different kinds of occupations by means of two modified scales measuring conformity by Santor, Messervey, and Kusumakar (2000 – scale for perceived peer pressure and scale for conformism in antisocial situations. The hypothesis of the study that workers’ conformism is expressed in a medium degree was confirmed partly. More than a half of the workers conform in a medium degree for taking risk, and for the use of alcohol and drugs, and for sexual relationships. More than a half of the respondents conform in a small degree for anti-social activities (like a theft. The workers were more inclined to conform for risk taking (10.9%, then – for the use of alcohol, drugs and for sexual relationships (8.7%, and in the lowest degree – for anti-social activities (6.5%. The workers who were inclined for the use of alcohol and drugs tended also to conform for anti-social activities.

  16. A novel conformation of gel grown biologically active cadmium nicotinate

    Science.gov (United States)

    Nair, Lekshmi P.; Bijini, B. R.; Divya, R.; Nair, Prabitha B.; Eapen, S. M.; Dileep Kumar, B. S.; Nishanth Kumar, S.; Nair, C. M. K.; Deepa, M.; Rajendra Babu, K.

    2017-11-01

    The elimination of toxic heavy metals by the formation of stable co-ordination compounds with biologically active ligands is applicable in drug designing. A new crystalline complex of cadmium with nicotinic acid is grown at ambient temperature using the single gel diffusion method in which the crystal structure is different from those already reported. Single crystal x-ray diffraction reveals the identity of crystal structure belonging to monoclinic system, P21/c space group with cell dimensions a = 17.220 (2) Å, b = 10.2480 (2) Å, c = 7.229(9) Å, β = 91.829(4)°. Powder x-ray diffraction analysis confirmed the crystallinity of the sample. The unidentate mode of co-ordination between the metal atom and the carboxylate group is supported by the Fourier Transform Infra Red spectral data. Thermal analysis ensures the thermal stability of the complex. Kinetic and thermodynamic parameters are also calculated. The stoichiometry of the complex is confirmed by the elemental analysis. The UV-visible spectral analysis shows the wide transparency window of the complex in the visible region. The band gap of the complex is found to be 3.92 eV. The complex shows excellent antibacterial and antifungal activity.

  17. SCR activity of conformed CuOx/ZrO2-SO4 catalysts

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Yates, Malcolm; Due-Hansen, Johannes

    2010-01-01

    CuOX/ZrO2-SO4 catalysts have been synthesised as conformed materials with the use of sepiolite as agglomerant and the performance in the NH3-SCR reaction with relation to biomass fired boiler units have been studied. The optimal Cu-loading of the catalysts is 3 wt.% CuO, both in terms of activity...

  18. Density functional theory studies of MTSL nitroxide side chain conformations attached to an activation loop

    CERN Document Server

    Concilio, Maria Grazia; Bayliss, Richard; Burgess, Selena G

    2016-01-01

    A quantum-mechanical (QM) method rooted on density functional theory (DFT) has been employed to determine conformations of the methane-thiosulfonate spin label (MTSL) attached to a fragment extracted from the activation loop of Aurora-A kinase. The features of the calculated energy surface revealed low energy barriers between isoenergetic minima and the system could be described in a population of 76 rotamers that can be also considered for other systems since it was found that the X3, X4 and X5 do not depend on the previous two dihedral angles. Conformational states obtained were seen to comparable to those obtained in the {\\alpha}-helix systems studied previously, indicating that the protein backbone does not affect the torsional profiles significantly and suggesting the possibility to use determined conformations for other protein systems for further modelling studies.

  19. Restriction of the conformational dynamics of the cyclic acyldepsipeptide antibiotics improves their antibacterial activity.

    Science.gov (United States)

    Carney, Daniel W; Schmitz, Karl R; Truong, Jonathan V; Sauer, Robert T; Sello, Jason K

    2014-02-05

    The cyclic acyldepsipeptide (ADEP) antibiotics are a new class of antibacterial agents that kill bacteria via a mechanism that is distinct from all clinically used drugs. These molecules bind and dysregulate the activity of the ClpP peptidase. The potential of these antibiotics as antibacterial drugs has been enhanced by the elimination of pharmacological liabilities through medicinal chemistry efforts. Here, we demonstrate that the ADEP conformation observed in the ADEP-ClpP crystal structure is fortified by transannular hydrogen bonding and can be further stabilized by judicious replacement of constituent amino acids within the peptidolactone core structure with more conformationally constrained counterparts. Evidence supporting constraint of the molecule into the bioactive conformer was obtained by measurements of deuterium-exchange kinetics of hydrogens that were proposed to be engaged in transannular hydrogen bonds. We show that the rigidified ADEP analogs bind and activate ClpP at lower concentrations in vitro. Remarkably, these compounds have up to 1200-fold enhanced antibacterial activity when compared to those with the peptidolactone core structure common to two ADEP natural products. This study compellingly demonstrates how rational modulation of conformational dynamics may be used to improve the bioactivities of natural products.

  20. Preferential binding of allosteric modulators to active and inactive conformational states of metabotropic glutamate receptors

    Directory of Open Access Journals (Sweden)

    Klein-Seetharaman Judith

    2008-02-01

    Full Text Available Abstract Metabotropic glutamate receptors (mGluRs are G protein coupled receptors that play important roles in synaptic plasticity and other neuro-physiological and pathological processes. Allosteric mGluR ligands are particularly promising drug targets because of their modulatory effects – enhancing or suppressing the response of mGluRs to glutamate. The mechanism by which this modulation occurs is not known. Here, we propose the hypothesis that positive and negative modulators will differentially stabilize the active and inactive conformations of the receptors, respectively. To test this hypothesis, we have generated computational models of the transmembrane regions of different mGluR subtypes in two different conformations. The inactive conformation was modeled using the crystal structure of the inactive, dark state of rhodopsin as template and the active conformation was created based on a recent model of the light-activated state of rhodopsin. Ligands for which the nature of their allosteric effects on mGluRs is experimentally known were docked to the modeled mGluR structures using ArgusLab and Autodock softwares. We find that the allosteric ligand binding pockets of mGluRs are overlapping with the retinal binding pocket of rhodopsin, and that ligands have strong preferences for the active and inactive states depending on their modulatory nature. In 8 out of 14 cases (57%, the negative modulators bound the inactive conformations with significant preference using both docking programs, and 6 out of 9 cases (67%, the positive modulators bound the active conformations. Considering results by the individual programs only, even higher correlations were observed: 12/14 (86% and 8/9 (89% for ArgusLab and 10/14 (71% and 7/9 (78% for AutoDock. These findings strongly support the hypothesis that mGluR allosteric modulation occurs via stabilization of different conformations analogous to those identified in rhodopsin where they are induced by

  1. The Rapid Response Radiation Survey (R3S) Mission Using the HiSat Conformal Satellite Architecture

    Science.gov (United States)

    Miller, Nathanael A.; Norman, Ryan B.; Soto, Hector L.; Stewart, Victor A.; Jones, Mark L.; Kowalski, Matthew C.; Ben Shabat, Adam; Gough, Kerry M.; Stavely, Rebecca L.; Shim, Alex C.; hide

    2015-01-01

    The Rapid Response Radiation Survey (R3S) experiment, designed as a quick turnaround mission to make radiation measurements in Low Earth Orbit (LEO), will fly as a hosted payload in partnership with NovaWurks using their Hyper-integrated Satlet (HISat) architecture. The need for the mission arises as the Nowcast of Atmospheric Ionization Radiation for Aviation Safety (NAIRAS) model moves from a research effort into an operational radiation assessment tool. Currently, airline professionals are the second largest demographic of radiation workers and to date their radiation exposure is undocumented in the USA. The NAIRAS model seeks to fill this information gap. The data collected by R3S, in addition to the complementary data from a NASA Langley Research Center (LaRC) atmospheric balloon mission entitled Radiation Dosimetry Experiment (RaD-X), will validate exposure prediction capabilities of NAIRAS. The R3S mission collects total dose and radiation spectrum measurements using a Teledyne µDosimeter and a Liulin-6SA2 LED spectrometer. These two radiation sensors provide a cross correlated radiometric measurement in combination with the Honeywell HMR2300 Smart Digital Magnetometer. The magnetometer assesses the Earth's magnetic field in the LEO environment and allows radiation dose to be mapped as a function of the Earth's magnetic shielding. R3S is also unique in that the radiation sensors will be exposed on the outer surface of the spacecraft, possibly making this the first measurements of the LEO radiation environment with bare sensors. Viability of R3S as an extremely fast turnaround mission is due, in part, to the nature of the robust, well-defined interfaces of the conformal satellite HiSat Architecture. The HiSat architecture, which was developed with the support of the Defense Advanced Research Projects Agency's (DARPA's) Phoenix Program, enabled the R3S system to advance from the first concept to delivery of preliminary design review (PDR) level documents in

  2. Functional brain activation differences in stuttering identified with a rapid fMRI sequence

    Science.gov (United States)

    Kraft, Shelly Jo; Choo, Ai Leen; Sharma, Harish; Ambrose, Nicoline G.

    2011-01-01

    The purpose of this study was to investigate whether brain activity related to the presence of stuttering can be identified with rapid functional MRI (fMRI) sequences that involved overt and covert speech processing tasks. The long-term goal is to develop sensitive fMRI approaches with developmentally appropriate tasks to identify deviant speech motor and auditory brain activity in children who stutter closer to the age at which recovery from stuttering is documented. Rapid sequences may be preferred for individuals or populations who do not tolerate long scanning sessions. In this report, we document the application of a picture naming and phoneme monitoring task in three minute fMRI sequences with adults who stutter (AWS). If relevant brain differences are found in AWS with these approaches that conform to previous reports, then these approaches can be extended to younger populations. Pairwise contrasts of brain BOLD activity between AWS and normally fluent adults indicated the AWS showed higher BOLD activity in the right inferior frontal gyrus (IFG), right temporal lobe and sensorimotor cortices during picture naming and and higher activity in the right IFG during phoneme monitoring. The right lateralized pattern of BOLD activity together with higher activity in sensorimotor cortices is consistent with previous reports, which indicates rapid fMRI sequences can be considered for investigating stuttering in younger participants. PMID:22133409

  3. A technique to reduce low dose region for craniospinal irradiation (CSI) with RapidArc and its dosimetric comparison with 3D conformal technique (3DCRT).

    Science.gov (United States)

    Srivastava, Roopam; Saini, Gagan; Sharma, Pramod Kumar; Chomal, Manish; Aagarwal, Anchal; Nangia, Sapna; Garg, Madhur

    2015-01-01

    We proposed a method to reduce the volume of normal tissues irradiated by low doses in patients receiving CSI with RapidArc (RA) using Avoidance-Sector technique (RA+AS) and to compare its dosimetric implications with RA using full-arc (RA+FA) and 3D conformal technique (3DCRT). Four patients of CSI were retrospectively planned with 3DCRT, RA+FA, and RA+AS. Conformity-Index (CI), Homogeneity-Index (HI), and Paddick Gradient-Index (GI) were calculated. Quantitative evaluation was done using DVH analysis for PTVs and OARs. When compared with 3DCRT, GI, CI, and HI were favorable to RA based techniques. In comparison with 3DCRT the doses to OARs were lower with RA+AS with the difference being statistically significant in most instances. RA+AS significantly decreases the dose to OARs and their volumes receiving low doses in comparison with RA+FA and 3DCRT.

  4. Conformational and dynamical properties of semiflexible polymers in the presence of active noise

    Science.gov (United States)

    Eisenstecken, Thomas; Ghavami, Ali; Mair, Alexander; Gompper, Gerhard; Winkler, Roland G.

    2017-08-01

    In the presence of active noise, flexible and semiflexible polymers exhibit drastically different conformational and dy-namical features compared to the case of thermal (white) noise only. For a non-Markovian exponentially correlated temporal noise (colored noise), flexible polymers swell with increasing noise strength, whereas semiflexible polymers shrink first and, for larger noise strengths, swell similar to flexible polymers. Thereby, a suitable treatment of the finite polymer contour length is essential. The finite contour length implies a strong dependence of the polymer relaxation times on the noise strengths. We discuss the conformational and dynamical aspects in terms of an analytical model, adopting the continuous Gaussian semiflexible polymer description. Moreover, results of computer simulations are shown and compared with analytical results.

  5. Conformation and activity alteration of horseradish peroxidase induced by the interaction with gene carrier polyethyleneimines

    Science.gov (United States)

    Huang, Aimin; Wei, Bangzhi; Mo, Junyong; Wang, Yajing; Ma, Lin

    2018-01-01

    Polyethyleneimine (PEI) has long been considered as ;golden standard; for polymeric gene delivery carriers. However the molecular basis of the cytotoxicity of PEI is poorly understood. Little is known about the effects of PEI on the structure and functions of biomacromolecules. In this work, fluorescence, UV-vis absorption, circular dichroism spectroscopy were conducted to investigate the influence of PEI of average molecular weight 25, 10 and 1.8 kDa (denoted as PEI25k, PEI10k and PEI1.8k) on the conformation of horseradish peroxidase (HRP) and its catalytic efficiency. Zeta-potential measurement and isothermal titration calorimetry were used to reveal the mechanism of the interaction between PEIs and HRP. PEIs were found to bind onto the surface of HRP predominantly via hydrophobic interaction and hydrogen bond or van der Waals interaction. The complex formation between HRP and PEI induced a more compact conformation of the enzyme and an increased hydrophobicity of the microenvironment surrounding heme pocket. The conformational change of HRP had little impact on the affinity towards H2O2 and phenol. However, the increase in the non-planarity of porphyrin ring in the heme group led to an increase in the exposure degree of the active center and thus an enhancement of catalytic efficiency of HRP in the presence of high molecular weight PEIs (PEI25k and PEI10k). The polymer size played an important role in PEI-HRP interaction. PEI of low molecular weight (PEI1.8k) was less efficient to alter the conformation and catalytic activity of HRP in aqueous solutions.

  6. Conformal optical elements for correcting wavefront distortions in YAG : Nd{sup 3+} active elements

    Energy Technology Data Exchange (ETDEWEB)

    Korolkov, V P; Nasyrov, R K; Poleshchuk, A G; Arapov, Yu D; Ivanov, A F

    2013-02-28

    Correction of the wavefront is studied for the light beam passing wide-aperture YAG : Nd3+ single-crystal rods, which are used as active elements in high-power solid-state lasers. A nonideal character of the crystal structure is responsible for the deformation of the wavefront of passing radiation. By using the halftone technology we have developed conformal aberration correctors capable of compensating rod nonuniformities and reducing the laser radiation divergence by an order of magnitude. The results obtained make it possible to employ optically nonuniform active elements in laser constructions. (laser optics 2012)

  7. Non-conformable, partial and conformable transposition

    DEFF Research Database (Denmark)

    König, Thomas; Mäder, Lars Kai

    2013-01-01

    Although member states are obliged to transpose directives into domestic law in a conformable manner and receive considerable time for their transposition activities, we identify three levels of transposition outcomes for EU directives: conformable, partially conformable and non-conformable...... and the Commission regarding a directive’s outcome, play a much more strategic role than has to date acknowledged in the transposition literature. Whereas disagreement of a member state delays conformable transposition, it speeds up non-conformable transposition. Disagreement of the Commission only prolongs...

  8. Search for Active-State Conformation of Drug Target GPCR Using Real-Coded Genetic Algorithm

    Science.gov (United States)

    Ishino, Yoko; Harada, Takanori; Aida, Misako

    G-Protein coupled receptors (GPCRs) comprise a large superfamily of proteins and are a target for nearly 50% of drugs in clinical use today. GPCRs have a unique structural motif, seven transmembrane helices, and it is known that agonists and antagonists dock with a GPCR in its ``active'' and ``inactive'' condition, respectively. Knowing conformations of both states is eagerly anticipated for elucidation of drug action mechanism. Since GPCRs are difficult to crystallize, the 3D structures of these receptors have not yet been determined by X-ray crystallography, except the inactive-state conformation of two proteins. The conformation of them enabled the inactive form of other GPCRs to be modeled by computer-aided homology modeling. However, to date, the active form of GPCRs has not been solved. This paper describes a novel method to predict the 3D structure of an active-state GPCR aiming at molecular docking-based virtual screening using real-coded genetic algorithm (real-coded GA), receptor-ligand docking simulations, and molecular dynamics (MD) simulations. The basic idea of the method is that the MD is first used to calculate an average 3D coordinates of all atoms of a GPCR protein against heat fluctuation on the pico- or nano- second time scale, and then real-coded GA involving receptor-ligand docking simulations functions to determine the rotation angle of each helix as a movement on wider time scale. The method was validated using human leukotriene B4 receptor BLT1 as a sample GPCR. Our study demonstrated that the established evolutionary search for the active state of the leukotriene receptor provided the appropriate 3D structure of the receptor to dock with its agonists.

  9. Conformational transitions during FtsK translocase activation of individual XerCD-dif recombination complexes.

    Science.gov (United States)

    Zawadzki, Pawel; May, Peter F J; Baker, Rachel A; Pinkney, Justin N M; Kapanidis, Achillefs N; Sherratt, David J; Arciszewska, Lidia K

    2013-10-22

    Three single-molecule techniques have been used simultaneously and in tandem to track the formation in vitro of single XerCD-dif recombination complexes. We observed the arrival of the FtsK translocase at individual preformed synaptic complexes and demonstrated the conformational change that occurs during their activation. We then followed the reaction intermediate transitions as Holliday junctions formed through catalysis by XerD, isomerized, and were converted by XerC to reaction products, which then dissociated. These observations, along with the calculated intermediate lifetimes, inform the reaction mechanism, which plays a key role in chromosome unlinking in most bacteria with circular chromosomes.

  10. Synthesis, preferred conformation, protease stability, and membrane activity of heptaibin, a medium-length peptaibiotic.

    Science.gov (United States)

    De Zotti, Marta; Biondi, Barbara; Peggion, Cristina; Park, Yoonkyung; Hahm, Kyung-Soo; Formaggio, Fernando; Toniolo, Claudio

    2011-08-01

    The medium-length peptaibiotics are characterized by a primary structure of 14-16 amino acid residues. Despite the interesting antibiotic and antifungal properties exhibited by these membrane-active peptides, their exact mechanism of action is still unknown. Here, we present our results on heptaibin, a 14-amino acid peptaibiotic found to exhibit antimicrobial activity against Staphylococcus aureus. We carried out the very challenging synthesis of heptaibin on solid phase and a detailed conformational analysis in solution. The peptaibiotic is folded in a mixed 3₁₀-/α-helix conformation which exhibits a remarkable amphiphilic character. We also find that it is highly stable toward degradation by proteolytic enzymes and nonhemolytic. Finally, fluorescence leakage experiments using small unilamellar vesicles of three different compositions revealed that heptaibin, although uncharged, is a selective compound for permeabilization of model membranes mimicking the overall negatively charged surface of Gram-positive bacteria. This latter finding is in agreement with the originally published antimicrobial activity data. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.

  11. Conformational similarity in the activation of caspase-3 and -7 revealed by the unliganded and inhibited structures of caspase-7

    Energy Technology Data Exchange (ETDEWEB)

    Agniswamy, Johnson; Fang, Bin; Weber, Irene T.; (GSU)

    2009-09-08

    Caspase-mediated apoptosis has important roles in normal cell differentiation and aging and in many diseases including cancer, neuromuscular disorders and neurodegenerative diseases. Therefore, modulation of caspase activity and conformational states is of therapeutic importance. We report crystal structures of a new unliganded conformation of caspase-7 and the inhibited caspase-7 with the tetrapeptide Ac-YVAD-Cho. Different conformational states and mechanisms for substrate recognition have been proposed based on unliganded structures of the redundant apoptotic executioner caspase-3 and -7. The current study shows that the executioner caspase-3 and -7 have similar conformations for the unliganded active site as well as the inhibitor-bound active site. The new unliganded caspase-7 structure exhibits the tyrosine flipping mechanism in which the Tyr230 has rotated to block entry to the S2 binding site similar to the active site conformation of unliganded caspase-3. The inhibited structure of caspase-7/YVAD shows that the P4 Tyr binds the S4 region specific to polar residues at the expense of a main chain hydrogen bond between the P4 amide and carbonyl oxygen of caspase-7 Gln 276, which is similar to the caspase-3 complex. This new knowledge of the structures and conformational states of unliganded and inhibited caspases will be important for the design of drugs to modulate caspase activity and apoptosis.

  12. Conformational Rigidity and Protein Dynamics at Distinct Timescales Regulate PTP1B Activity and Allostery.

    Science.gov (United States)

    Choy, Meng S; Li, Yang; Machado, Luciana E S F; Kunze, Micha B A; Connors, Christopher R; Wei, Xingyu; Lindorff-Larsen, Kresten; Page, Rebecca; Peti, Wolfgang

    2017-02-16

    Protein function originates from a cooperation of structural rigidity, dynamics at different timescales, and allostery. However, how these three pillars of protein function are integrated is still only poorly understood. Here we show how these pillars are connected in Protein Tyrosine Phosphatase 1B (PTP1B), a drug target for diabetes and cancer that catalyzes the dephosphorylation of numerous substrates in essential signaling pathways. By combining new experimental and computational data on WT-PTP1B and ≥10 PTP1B variants in multiple states, we discovered a fundamental and evolutionarily conserved CH/π switch that is critical for positioning the catalytically important WPD loop. Furthermore, our data show that PTP1B uses conformational and dynamic allostery to regulate its activity. This shows that both conformational rigidity and dynamics are essential for controlling protein activity. This connection between rigidity and dynamics at different timescales is likely a hallmark of all enzyme function. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Recent activity of the Rapid Burster (MXB 1730-335)

    NARCIS (Netherlands)

    Kuulkers, E.; Brandt, S.; Markwardt, C.; Remillard, R.A.; Shaw, S.; Beckmann, V.; Chenevez, J.; Courvoisier, T.J.L.; Domingo, A.; Ebisawa, K.; Jonker, P.; Kretschmar, P.; Oosterbroek, T.; Paizis, A.; Risquez, D.; Sanchez-Fernandez, C.; Wijnands, R.

    2008-01-01

    Observations taken as part of the INTEGRAL Galactic bulge monitoring program (see ATel #1385) on 2008, February 23 13:32-17:13 (UT) showed bursting activity from the X-ray transient, the Rapid Burster (MXB 1730-335). During one of the 1800-sec pointings when the source was in the field- of-view of

  14. Recent activity of the Rapid Burster (MXB 1730-335)

    DEFF Research Database (Denmark)

    Kuulkers, E.; Brandt, Søren Kristian; Markwardt, C.

    2008-01-01

    Observations taken as part of the INTEGRAL Galactic bulge monitoring program (see ATel #1385) on 2008, February 23 13:32-17:13 (UT) showed bursting activity from the X-ray transient, the Rapid Burster (MXB 1730-335). During one of the 1800-sec pointings when the source was in the field- of-view o...

  15. Active site topologies and cofactor-mediated conformational changes of nitric-oxide synthases.

    Science.gov (United States)

    Gerber, N C; Rodriguez-Crespo, I; Nishida, C R; Ortiz de Montellano, P R

    1997-03-07

    The active site topologies of neuronal (nNOS), endothelial (eNOS), and inducible (iNOS) nitric-oxide synthases heterologously expressed in Escherichia coli have been examined using three aryldiazene (Ar-N=NH) probes. The topological information derives from (a) the rate and extent of aryl-iron complex formation in the presence and absence of tetrahydrobiopterin (H4B), Ca2+-dependent calmodulin (CaM), and L-arginine, and (b) the N-phenylprotoporphyrin IX regioisomer ratios obtained upon migration of the phenyl of the phenyl-iron complex to the heme nitrogen atoms. The N-phenylprotoporphyrin ratios indicate that the three NOS isoforms have related active site topologies with unencumbered space above all four pyrrole rings but particularly above pyrrole ring D. H4B binds directly above the heme pyrrole ring D or causes a conformational change that constricts that region, because H4B markedly decreases phenyl migration to pyrrole ring D. Small CaM-dependent changes in the nNOS N-phenylporphyrin isomer pattern are consistent with a conformational link between the CaM and heme sites in this protein. The ceiling height directly above the heme iron atom differs among the isoforms and is lower than in the P450 enzymes because only nNOS and iNOS react with 2-naphthyldiazene, and none of the isoforms reacts with p-biphenyldiazene. L-Arg blocks access to the heme iron atom in all three NOS isoforms and nearly suppresses the phenyldiazene reaction. The data indicate that topological differences, including differences in the size of the active site, are superimposed on the structural similarities among the NOS active sites.

  16. Multiplexed chromosome conformation capture sequencing for rapid genome-scale high-resolution detection of long-range chromatin interactions.

    Science.gov (United States)

    Stadhouders, Ralph; Kolovos, Petros; Brouwer, Rutger; Zuin, Jessica; van den Heuvel, Anita; Kockx, Christel; Palstra, Robert-Jan; Wendt, Kerstin S; Grosveld, Frank; van Ijcken, Wilfred; Soler, Eric

    2013-03-01

    Chromosome conformation capture (3C) technology is a powerful and increasingly popular tool for analyzing the spatial organization of genomes. Several 3C variants have been developed (e.g., 4C, 5C, ChIA-PET, Hi-C), allowing large-scale mapping of long-range genomic interactions. Here we describe multiplexed 3C sequencing (3C-seq), a 4C variant coupled to next-generation sequencing, allowing genome-scale detection of long-range interactions with candidate regions. Compared with several other available techniques, 3C-seq offers a superior resolution (typically single restriction fragment resolution; approximately 1-8 kb on average) and can be applied in a semi-high-throughput fashion. It allows the assessment of long-range interactions of up to 192 genes or regions of interest in parallel by multiplexing library sequencing. This renders multiplexed 3C-seq an inexpensive, quick (total hands-on time of 2 weeks) and efficient method that is ideal for the in-depth analysis of complex genetic loci. The preparation of multiplexed 3C-seq libraries can be performed by any investigator with basic skills in molecular biology techniques. Data analysis requires basic expertise in bioinformatics and in Linux and Python environments. The protocol describes all materials, critical steps and bioinformatics tools required for successful application of 3C-seq technology.

  17. Nontargeted, Rapid Screening of Extra Virgin Olive Oil Products for Authenticity Using Near-Infrared Spectroscopy in Combination with Conformity Index and Multivariate Statistical Analyses.

    Science.gov (United States)

    Karunathilaka, Sanjeewa R; Kia, Ali-Reza Fardin; Srigley, Cynthia; Chung, Jin Kyu; Mossoba, Magdi M

    2016-10-01

    A rapid tool for evaluating authenticity was developed and applied to the screening of extra virgin olive oil (EVOO) retail products by using Fourier-transform near infrared (FT-NIR) spectroscopy in combination with univariate and multivariate data analysis methods. Using disposable glass tubes, spectra for 62 reference EVOO, 10 edible oil adulterants, 20 blends consisting of EVOO spiked with adulterants, 88 retail EVOO products and other test samples were rapidly measured in the transmission mode without any sample preparation. The univariate conformity index (CI) and the multivariate supervised soft independent modeling of class analogy (SIMCA) classification tool were used to analyze the various olive oil products which were tested for authenticity against a library of reference EVOO. Better discrimination between the authentic EVOO and some commercial EVOO products was observed with SIMCA than with CI analysis. Approximately 61% of all EVOO commercial products were flagged by SIMCA analysis, suggesting that further analysis be performed to identify quality issues and/or potential adulterants. Due to its simplicity and speed, FT-NIR spectroscopy in combination with multivariate data analysis can be used as a complementary tool to conventional official methods of analysis to rapidly flag EVOO products that may not belong to the class of authentic EVOO. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  18. Stereoselectivity of enoyl-CoA hydratase results from preferential activation of one of two bound substrate conformers.

    Science.gov (United States)

    Bell, Alasdair F; Feng, Yuguo; Hofstein, Hilary A; Parikh, Sapan; Wu, Jiaquan; Rudolph, Michael J; Kisker, Caroline; Whitty, Adrian; Tonge, Peter J

    2002-11-01

    Enoyl-CoA hydratase catalyzes the hydration of trans-2-crotonyl-CoA to 3(S)- and 3(R)-hydroxybutyryl-CoA with a stereoselectivity (3(S)/3(R)) of 400,000 to 1. Importantly, Raman spectroscopy reveals that both the s-cis and s-trans conformers of the substrate analog hexadienoyl-CoA are bound to the enzyme, but that only the s-cis conformer is polarized. This selective polarization is an example of ground state strain, indicating the existence of catalytically relevant ground state destabilization arising from the selective complementarity of the enzyme toward the transition state rather than the ground state. Consequently, the stereoselectivity of the enzyme-catalyzed reaction results from the selective activation of one of two bound substrate conformers rather than from selective binding of a single conformer. These findings have important implications for inhibitor design and the role of ground state interactions in enzyme catalysis.

  19. QSAR study and conformational analysis of 4-arylthiazolylhydrazones derived from 1-indanones with anti-Trypanosoma cruzi activity.

    Science.gov (United States)

    Noguera, Guido J; Fabian, Lucas E; Lombardo, Elisa; Finkielsztein, Liliana

    2015-10-12

    A set of 4-arylthiazolylhydrazones derived from 1-indanones (TZHs) previously synthesized and assayed against Trypanosoma cruzi, the causative agent of Chagas disease, were explored in terms of conformational analysis. We found that TZHs can adopt four minimum energy conformations: cis (A, B and C) and trans. The possible bioactive conformation was selected by a 3D-QSAR model. Different molecular parameters were calculated to produce QSAR second-generation models. These QSAR results are discussed in conjunction with conformational analysis from molecular modeling studies. The main factor to determine the activity of the compounds was the partial charge at the N(3) atom (qN3). The predictive ability of the QSAR equations proposed was experimentally validated. The QSAR models developed in this study will be helpful to design novel potent TZHs. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. A model for the conformational activation of the structurally quiescent metalloprotease ADAMTS13 by von willebrand factor

    Science.gov (United States)

    South, Kieron; Freitas, Marta O.; Lane, David A.

    2017-01-01

    Blood loss is prevented by the multidomain glycoprotein von Willebrand factor (VWF), which binds exposed collagen at damaged vessels and captures platelets. VWF is regulated by the metalloprotease ADAMTS13, which in turn is conformationally activated by VWF. To delineate the structural requirements for VWF-mediated conformational activation of ADAMTS13, we performed binding and functional studies with a panel of truncated ADAMTS13 variants. We demonstrate that both the isolated CUB1 and CUB2 domains in ADAMTS13 bind to the spacer domain exosite of a truncated ADAMTS13 variant, MDTCS (KD of 135 ± 1 0.1 nm and 86.9 ± 9.0 nm, respectively). However, only the CUB1 domain inhibited proteolytic activity of MDTCS. Moreover, ADAMTS13ΔCUB2, unlike ADAMTS13ΔCUB1-2, exhibited activity similar to wild-type ADAMTS13 and could be activated by VWF D4-CK. The CUB2 domain is, therefore, not essential for maintaining the inactive conformation of ADAMTS13. Both CUB domains could bind to the VWF D4-CK domain fragment (KD of 53.7 ± 2.1 nm and 84.3 ± 2.0 nm, respectively). However, deletion of both CUB domains did not prevent VWF D4-CK binding, suggesting that competition for CUB-domain binding to the spacer domain is not the dominant mechanism behind the conformational activation. ADAMTS13ΔTSP8-CUB2 could no longer bind to VWF D4-CK, and deletion of TSP8 abrogated ADAMTS13 conformational activation. These findings support an ADAMTS13 activation model in which VWF D4-CK engages the TSP8-CUB2 domains, inducing the conformational change that disrupts the CUB1-spacer domain interaction and thereby activates ADAMTS13. PMID:28209710

  1. Rapid optical determination of β-lactamase and antibiotic activity

    Science.gov (United States)

    2014-01-01

    Background The absence of rapid tests evaluating antibiotic susceptibility results in the empirical prescription of antibiotics. This can lead to treatment failures due to escalating antibiotic resistance, and also furthers the emergence of drug-resistant bacteria. This study reports a rapid optical method to detect β-lactamase and thereby assess activity of β-lactam antibiotics, which could provide an approach for targeted prescription of antibiotics. The methodology is centred on a fluorescence quenching based probe (β-LEAF – β-Lactamase Enzyme Activated Fluorophore) that mimics the structure of β-lactam antibiotics. Results The β-LEAF assay was performed for rapid determination of β-lactamase production and activity of β-lactam antibiotic (cefazolin) on a panel of Staphylococcus aureus ATCC strains and clinical isolates. Four of the clinical isolates were determined to be lactamase producers, with the capacity to inactivate cefazolin, out of the twenty-five isolates tested. These results were compared against gold standard methods, nitrocefin disk test for β-lactamase detection and disk diffusion for antibiotic susceptibility, showing results to be largely consistent. Furthermore, in the sub-set of β-lactamase producers, it was demonstrated and validated that multiple antibiotics (cefazolin, cefoxitin, cefepime) could be assessed simultaneously to predict the antibiotic that would be most active for a given bacterial isolate. Conclusions The study establishes the rapid β-LEAF assay for β-lactamase detection and prediction of antibiotic activity using S. aureus clinical isolates. Although the focus in the current study is β-lactamase-based resistance, the overall approach represents a broad diagnostic platform. In the long-term, these studies form the basis for the development of assays utilizing a broader variety of targets, pathogens and drugs. PMID:24708478

  2. Effects of Pulsed Electric Field (PEF) Treatment on Enhancing Activity and Conformation of α-Amylase.

    Science.gov (United States)

    Tian, Mei-ling; Fang, Ting; Du, Mu-ying; Zhang, Fu-sheng

    2016-04-01

    To explore an efficient, safe, and speedy application of pulsed electric field (PEF) technology for enzymatic modification, effects of PEF treatment on the enzymatic activity, property and kinetic parameters of α-amylase were investigated. Conformational transitions were also studied with the aid of circular dichroism (CD) and fluorescence spectra. The maximum enzymatic activity of α-amylase was obtained under 15 kV/cm electric field intensity and 100 mL/min flow velocity PEF treatment, in which the enzymatic activity increased by 22.13 ± 1.14% compared with control. The activation effect could last for 18 h at 4 °C. PEF treatment could widen the range of optimum temperature for α-amylase, however, it barely exerted any effect on the optimum pH. On the other hand, α-amylase treated by PEF showed an increase of Vmax, t1/2 and ΔG, whereas a decrease of Km and k were observed. Furthermore, it can be observed from fluorescence and CD spectra that PEF treatment had increased the number of amino acid residues, especially that of tryptophan, on α-amylase surface with enhanced α-helices by 34.76% and decreased random coil by 12.04% on α-amylase when compared with that of untreated. These changes in structure had positive effect on enhancing α-amylase activity and property.

  3. Fragment-based identification of determinants of conformational and spectroscopic change at the ricin active site

    Directory of Open Access Journals (Sweden)

    Soares Alexei S

    2007-11-01

    Full Text Available Abstract Background Ricin is a potent toxin and known bioterrorism threat with no available antidote. The ricin A-chain (RTA acts enzymatically to cleave a specific adenine base from ribosomal RNA, thereby blocking translation. To understand better the relationship between ligand binding and RTA active site conformational change, we used a fragment-based approach to find a minimal set of bonding interactions able to induce rearrangements in critical side-chain positions. Results We found that the smallest ligand stabilizing an open conformer of the RTA active site pocket was an amide group, bound weakly by only a few hydrogen bonds to the protein. Complexes with small amide-containing molecules also revealed a switch in geometry from a parallel towards a splayed arrangement of an arginine-tryptophan cation-pi interaction that was associated with an increase and red-shift in tryptophan fluorescence upon ligand binding. Using the observed fluorescence signal, we determined the thermodynamic changes of adenine binding to the RTA active site, as well as the site-specific binding of urea. Urea binding had a favorable enthalpy change and unfavorable entropy change, with a ΔH of -13 ± 2 kJ/mol and a ΔS of -0.04 ± 0.01 kJ/(K*mol. The side-chain position of residue Tyr80 in a complex with adenine was found not to involve as large an overlap of rings with the purine as previously considered, suggesting a smaller role for aromatic stacking at the RTA active site. Conclusion We found that amide ligands can bind weakly but specifically to the ricin active site, producing significant shifts in positions of the critical active site residues Arg180 and Tyr80. These results indicate that fragment-based drug discovery methods are capable of identifying minimal bonding determinants of active-site side-chain rearrangements and the mechanistic origins of spectroscopic shifts. Our results suggest that tryptophan fluorescence provides a sensitive probe for the

  4. Efficiency of Stereotactic Conformal Radiotherapy in Lung Metastases with Active Breathing Control

    Directory of Open Access Journals (Sweden)

    Olga Yu. Anikeeva, PhD

    2013-06-01

    Full Text Available Twenty four patients with lung metastases underwent radiosurgery treatment between October 2010 and December 2012. Stereotactic conformal high-dose radiation therapy with Active Breathing Control (ABC was conducted using the volumetric modulated arc therapy (VMAT technique. The median overall follow-up was 18 months (range 6-24 months, overall survival was 75%, and local control rate was 92%. The median time to progression was 4 months (range 1-18 months.There have been no cases of leucopenia, radiation esophagitis, mediastinitis or severe acute radiation pneumonitis. The late radiation effects Grade 2, according to the LENT SOMA scales, was observed in one patient (4%. The results of this study indicate that the usage of the stereotactic high-dose radiation therapy with ABC is safe and effective in the treatment of lung metastases.

  5. Fate of lipoprotein lipase taken up by the rat liver. Evidence for a conformational change with loss of catalytic activity.

    Science.gov (United States)

    Chajek-Shaul, T; Friedman, G; Ziv, E; Bar-On, H; Bengtsson-Olivecrona, G

    1988-11-25

    When isolated rat livers were perfused with medium containing lipoprotein lipase, 40-60% was taken up during a single passage. This value was similar for lipoprotein lipase derived from culture medium of rat preadipocytes, and for lipoprotein lipase purified from bovine milk. It was also, similar, irrespective of the lipoprotein lipase concentration, at least up to 1 microgram/ml. Immediately following its uptake by the liver, a large fraction of the lipoprotein lipase could be released by heparin, but the magnitude of this fraction decreased with time. The enzyme lost its catalytic activity rather rapidly, but its degradation to acid-soluble products, or to larger fragments, was much slower. On heparin-agarose chromatography, the enzyme taken up by the liver eluted at a lower salt concentration than the original lipoprotein lipase preparation. This change in affinity for heparin suggests that the originally dimeric lipoprotein lipase had dissociated into monomers, in analogy to the findings in model experiments. It is suggested that the initial uptake of lipoprotein lipase occurs by binding to a polyanion at the liver cell surface. This is followed by endocytosis and dissociation of the enzyme from its heparan sulfate-like binding site. Acidification of the endosome may cause a conformational change in the lipase molecule with dissociation to inactive monomers, preceding ultimate proteolytic degradation.

  6. A Rapidly Evolving Active Region NOAA 8032 observed on April ...

    Indian Academy of Sciences (India)

    1997-04-15

    The active region NOAA 8032 of April 15, 1997 was observed to evolve rapidly. The GOES X-ray data showed a number of sub-flares and two C-class flares during the 8-9 hours of its evolution. The magnetic evolution of this region is studied to ascertain its role in flare production. Large changes were observed in magnetic ...

  7. Use of a conformational switching aptamer for rapid and specific ex vivo identification of central nervous system lymphoma in a xenograft model.

    Directory of Open Access Journals (Sweden)

    Joseph F Georges

    Full Text Available Improved tools for providing specific intraoperative diagnoses could improve patient care. In neurosurgery, intraoperatively differentiating non-operative lesions such as CNS B-cell lymphoma from operative lesions can be challenging, often necessitating immunohistochemical (IHC procedures which require up to 24-48 hours. Here, we evaluate the feasibility of generating rapid ex vivo specific labeling using a novel lymphoma-specific fluorescent switchable aptamer. Our B-cell lymphoma-specific switchable aptamer produced only low-level fluorescence in its unbound conformation and generated an 8-fold increase in fluorescence once bound to its target on CD20-positive lymphoma cells. The aptamer demonstrated strong binding to B-cell lymphoma cells within 15 minutes of incubation as observed by flow cytometry. We applied the switchable aptamer to ex vivo xenograft tissue harboring B-cell lymphoma and astrocytoma, and within one hour specific visual identification of lymphoma was routinely possible. In this proof-of-concept study in human cell culture and orthotopic xenografts, we conclude that a fluorescent switchable aptamer can provide rapid and specific labeling of B-cell lymphoma, and that developing aptamer-based labeling approaches could simplify tissue staining and drastically reduce time to histopathological diagnoses compared with IHC-based methods. We propose that switchable aptamers could enhance expeditious, accurate intraoperative decision-making.

  8. Membrane-bound conformation and phospholipid components modulate membrane-damaging activity of Taiwan cobra cardiotoxins.

    Science.gov (United States)

    Kao, Pei-Hsiu; Lin, Shinne-Ren; Wu, Ming-Jung; Chang, Long-Sen

    2009-04-01

    Membrane-damaging activity of Naja naja atra cardiotoxin 3 (CTX3) on 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC)/1,2-dimyristoyl-phosphatidic acid (DMPA) vesicles was approximately 3-fold that of N. naja atra cardiotoxin 4 (CTX4), while CTX3 and CTX4 displayed insignificantly permeabilizing activity in 1,2-dipalmitoyl-phosphatidylcholine (DPPC)/DMPA vesicles. Phospholipid-binding capability and oligomeric assembly upon binding with lipid vesicles did not closely correlate with membrane-damaging potency of CTX3 and CTX4. Geometrical arrangement of CTX3 in contact with POPC/DMPA vesicles was different from that noted with CTX4, and binding forces between CTX3 and POPC/DMPA were stronger than those between CTX4 and POPC/DMPA. Unlike POPC/DMPA, the interaction between CTXs and DPPC/DMPA was drastically reduced by increasing salt concentration. Color transformation of phospholipid/polydiacetylene membrane assay and FTIR spectra analyses revealed that CTX3 and CTX4 adopted different conformationsand modes upon absorption on POPC/DMPA and DPPC/DMPA vesicles. Taken together, our data show that, in addition to membrane packing density and phospholipid-binding capability, membrane-bound conformation of CTXs plays a vital role in displaying membrane-damaging activity.

  9. Adherent and Conformal Zn(S,O,OH) Thin Films by Rapid Chemical Bath Deposition with Hexamethylenetetramine Additive.

    Science.gov (United States)

    Opasanont, Borirak; Van, Khoa T; Kuba, Austin G; Choudhury, Kaushik Roy; Baxter, Jason B

    2015-06-03

    ZnS is a wide band gap semiconductor whose many applications, such as photovoltaic buffer layers, require uniform and continuous films down to several nanometers thick. Chemical bath deposition (CBD) is a simple, low-cost, and scalable technique to deposit such inorganic films. However, previous attempts at CBD of ZnS have often resulted in nodular noncontinuous films, slow growth rates at low pH, and high ratio of oxygen impurities at high pH. In this work, ZnS thin films were grown by adding hexamethylenetetramine (HMTA) to a conventional recipe that uses zinc sulfate, nitrilotriacetic acid trisodium salt, and thioacetamide. Dynamic bath characterization showed that HMTA helps the bath to maintain near-neutral pH and also acts as a catalyst, which leads to fast nucleation and deposition rates, continuous films, and less oxygen impurities in the films. Films deposited on glass from HMTA-containing bath were uniform, continuous, and 90 nm thick after 1 h, as opposed to films grown without HMTA that were ∼3 times thinner and more nodular. On Cu2(Zn,Sn)Se4, films grown with HMTA were continuous within 10 min. The films have comparatively few oxygen impurities, with S/(S+O) atomic ratio of 88%, and high optical transmission of 98% at 360 nm. The Zn(S,O,OH) films exhibit excellent adhesion to glass and high resistivity, which make them ideal nucleation layers for other metal sulfides. Their promise as a nucleation layer was demonstrated with the deposition of thin, continuous Sb2S3 overlayers. This novel HMTA chemistry enables rapid deposition of Zn(S,O,OH) thin films to serve as a nucleation layer, a photovoltaic buffer layer, or an extremely thin continuous coating for thin film applications. HMTA may also be applied in a similar manner for solution deposition of other metal chalcogenide and oxide thin films with superior properties.

  10. Neural signatures of social conformity: A coordinate-based activation likelihood estimation meta-analysis of functional brain imaging studies.

    Science.gov (United States)

    Wu, Haiyan; Luo, Yi; Feng, Chunliang

    2016-12-01

    People often align their behaviors with group opinions, known as social conformity. Many neuroscience studies have explored the neuropsychological mechanisms underlying social conformity. Here we employed a coordinate-based meta-analysis on neuroimaging studies of social conformity with the purpose to reveal the convergence of the underlying neural architecture. We identified a convergence of reported activation foci in regions associated with normative decision-making, including ventral striatum (VS), dorsal posterior medial frontal cortex (dorsal pMFC), and anterior insula (AI). Specifically, consistent deactivation of VS and activation of dorsal pMFC and AI are identified when people's responses deviate from group opinions. In addition, the deviation-related responses in dorsal pMFC predict people's conforming behavioral adjustments. These are consistent with current models that disagreement with others might evoke "error" signals, cognitive imbalance, and/or aversive feelings, which are plausibly detected in these brain regions as control signals to facilitate subsequent conforming behaviors. Finally, group opinions result in altered neural correlates of valuation, manifested as stronger responses of VS to stimuli endorsed than disliked by others. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Structural analyses of human thymidylate synthase reveal a site that may control conformational switching between active and inactive states.

    Science.gov (United States)

    Chen, Dan; Jansson, Anna; Sim, Daniel; Larsson, Andreas; Nordlund, Pär

    2017-08-11

    Thymidylate synthase (TS) is the sole enzyme responsible for de novo biosynthesis of thymidylate (TMP) and is essential for cell proliferation and survival. Inhibition of human TS (hTS) has been extensively investigated for cancer chemotherapy, but several aspects of its activity and regulation are still uncertain. In this study, we performed comprehensive structural and biophysical studies of hTS using crystallography and thermal shift assay and provided the first detailed structural information on the conformational changes induced by ligand binding to the hTS active site. We found that upon binding of the antifolate agents raltitrexed and nolatrexed, the two insert regions in hTS, the functions of which are unclear, undergo positional shifts toward the catalytic center. We investigated the inactive conformation of hTS and found that the two insert regions are also involved in the conformational transition between the active and inactive state of hTS. Moreover, we identified a ligand-binding site in the dimer interface, suggesting that the cavity in the dimer interface could serve as an allosteric site of hTS to regulate the conformational switching between the active and inactive states. On the basis of these findings, we propose a regulatory mechanism of hTS activity that involves allosteric regulation of interactions of hTS with its own mRNA depending on cellular demands for TMP. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Interconversion of active and inactive conformations of urokinase-type plasminogen activator

    DEFF Research Database (Denmark)

    Liu, Zhuo; Kromann-Hansen, Tobias; Lund, Ida K.

    2012-01-01

    The catalytic activity of serine proteases depends on a salt-bridge between the amino group of residue 16 and the side chain of Asp194. The salt-bridge stabilizes the oxyanion hole and the S1 specificity pocket of the protease. Some serine proteases exist in only partially active forms, in which ...

  13. Researchers rapidly respond to submarine activity at Loihi Volcano, Hawaii

    Science.gov (United States)

    The 1996 Loihi Science Team

    The largest swarm of earthquakes ever observed at a Hawaiian volcano occurred at Loihi Seamount during July and early August 1996. The earthquake activity formed a large summit pit crater similar to those observed at Kilauea, and hydrothermal activity led to the formation of intense hydrothermal plumes in the ocean surrounding the summit. To investigate this event, the Rapid Response Cruise (RRC) was dispatched to Loihi in early August and two previously planned LONO cruises (named for a Hawaiian warrior god) sailed in September and October on the R/V Kaimikai-O-Kanaloa. Calm weather and a newly refurbished ship provided excellent opportunities for documenting the volcanic, hydrothermal plume, vent, and biological activities associated with the earthquake swarm.

  14. Conformational Flexibility of a Short Loop near the Active Site of the SARS-3CLpro is Essential to Maintain Catalytic Activity

    Science.gov (United States)

    Li, Chunmei; Teng, Xin; Qi, Yifei; Tang, Bo; Shi, Hailing; Ma, Xiaomin; Lai, Luhua

    2016-02-01

    The SARS 3C-like proteinase (SARS-3CLpro), which is the main proteinase of the SARS coronavirus, is essential to the virus life cycle. This enzyme has been shown to be active as a dimer in which only one protomer is active. However, it remains unknown how the dimer structure maintains an active monomer conformation. It has been observed that the Ser139-Leu141 loop forms a short 310-helix that disrupts the catalytic machinery in the inactive monomer structure. We have tried to disrupt this helical conformation by mutating L141 to T in the stable inactive monomer G11A/R298A/Q299A. The resulting tetra-mutant G11A/L141T/R298A/Q299A is indeed enzymatically active as a monomer. Molecular dynamics simulations revealed that the L141T mutation disrupts the 310-helix and helps to stabilize the active conformation. The coil-310-helix conformational transition of the Ser139-Leu141 loop serves as an enzyme activity switch. Our study therefore indicates that the dimer structure can stabilize the active conformation but is not a required structure in the evolution of the active enzyme, which can also arise through simple mutations.

  15. The effect of methyl-donated hydrogen bonding on active site conformations of hyaluronate lyase

    Science.gov (United States)

    Migues, Angela N.; Vergenz, Robert A.; Moore, Kevin B.

    2010-03-01

    Geometric evidence shows a val-A252 methyl-donated (MD) hydrogen bond (HB) in hyaluronate lyase (Streptococcus pneumoniae) interacts with nearby NH--O and OH--O HBs, distorting active-site helical structure. Results for model fragment A248-254 are based on experimental heavy atom positions with ab initio hydrogen atoms. The MDHB, with (H-O distance, donor-H-O angle) = (2.3å; 174^o), exhibits more favorable geometry than thr-A253 OH--O HB (1.8å; 170^o) to the same ala-249 C=O. Consequently, thr-253 N-H--O interaction is forced closer to lys-250 C=O than ala-249 C=O(2.6 versus 2.7å). A novel method has been developed to quantify the effects of atomic diplacements on motions of neighboring helices. A coordinate system was established to track the movement of specific residues and to ascertain the effect of such motions on active site conformations.

  16. Rapid neutrophil adhesion to activated endothelium mediated by GMP-140.

    Science.gov (United States)

    Geng, J G; Bevilacqua, M P; Moore, K L; McIntyre, T M; Prescott, S M; Kim, J M; Bliss, G A; Zimmerman, G A; McEver, R P

    1990-02-22

    Granule membrane protein-140 (GMP-140), a membrane glycoprotein of platelet and endothelial cell secretory granules, is rapidly redistributed to the plasma membrane during cellular activation and degranulation. Also known as PADGEM protein, GMP-140 is structurally related to two molecules involved in leukocyte adhesion to vascular endothelium: ELAM-1, a cytokine-inducible endothelial cell receptor for neutrophils, and the MEL-14 lymphocyte homing receptor. These three proteins define a new gene family, termed selectins, each of which contains an N-terminal lectin domain, followed by an epidermal growth factor-like module, a variable number of repeating units related to those in complement-binding proteins, a transmembrane domain, and a short cytoplasmic tail. Here we demonstrate that GMP-140 can mediate leukocyte adhesion, thus establishing a functional similarity with the other selectins. Human neutrophils and promyelocytic HL-60 cells bind specifically to COS cells transfected with GMP-140 complementary DNA and to microtitre wells coated with purified GMP-140. Cell binding does not require active neutrophil metabolism but is dependent on extracellular Ca2+. Within minutes after stimulation with phorbol esters or histamine, human endothelial cells become adhesive for neutrophils; this interaction is inhibited by antibodies to GMP-140. Thus, GMP-140 expressed by activated endothelium might promote rapid neutrophil targeting to sites of acute inflammation.

  17. Rate of hydrolysis in ATP synthase is fine-tuned by  -subunit motif controlling active site conformation

    KAUST Repository

    Beke-Somfai, T.

    2013-01-23

    Computer-designed artificial enzymes will require precise understanding of how conformation of active sites may control barrier heights of key transition states, including dependence on structure and dynamics at larger molecular scale. F(o)F(1) ATP synthase is interesting as a model system: a delicate molecular machine synthesizing or hydrolyzing ATP using a rotary motor. Isolated F(1) performs hydrolysis with a rate very sensitive to ATP concentration. Experimental and theoretical results show that, at low ATP concentrations, ATP is slowly hydrolyzed in the so-called tight binding site, whereas at higher concentrations, the binding of additional ATP molecules induces rotation of the central γ-subunit, thereby forcing the site to transform through subtle conformational changes into a loose binding site in which hydrolysis occurs faster. How the 1-Å-scale rearrangements are controlled is not yet fully understood. By a combination of theoretical approaches, we address how large macromolecular rearrangements may manipulate the active site and how the reaction rate changes with active site conformation. Simulations reveal that, in response to γ-subunit position, the active site conformation is fine-tuned mainly by small α-subunit changes. Quantum mechanics-based results confirm that the sub-Ångström gradual changes between tight and loose binding site structures dramatically alter the hydrolysis rate.

  18. EFFECT OF DIVALENT CATIONS ON THE ACTIVITY AND CONFORMATION OF YEAST ALCOHOL DEHYDROGENASE

    Directory of Open Access Journals (Sweden)

    Rizwanul Haque

    2012-12-01

    Full Text Available The divalent metal chlorides affect the activity of yeast alcohol dehydrogenase (YADH. The activity of the enzyme in the presence of 20 µM of these metal chlorides decreased in the following order: CaCl2 > MgCl2 > no salt > MnCl2 > CoCl2 > CuCl2 > CdCl2 . The EC50 values for the incubation of YADH in the presence of CaCl 2 , MgCl2 , MnCl2 , CoCl2 , CuCl2 and CdCl2 were 14.5, 37.8, 0.25, 0.21, 0.18 and 0.005 mM, respectively. The most potent inhibitor was CdCl2 . Fluorescence studies revealed that the conformation of YADH undergoes huge changes in the presence of these metal chlorides. By far UV-CD spectra, some secondary structural changes were observed in YADH in the presence of CaCl2 , MgCl2 , MnCl2 and CoCl2 , however the changes were very significant in case of CdCl2 and CuCl2 . The removal of zinc from YADH resulted in complete loss of enzymatic activity which is regained back by addition of Zn. Mg, Ca and Mn can substitute Zn in YADH, and the enzyme exhibits comparable activity as in presence of Zn. However, Co, Cu, and Cd cannot substitute Zn in YADH. The results obtained here might be useful in the biotechnological applications of alcohol dehydrogenase.

  19. Epidemiology and Clinical Characteristics of Rapid Response Team Activations

    Directory of Open Access Journals (Sweden)

    Sei Won Kim

    2017-05-01

    Full Text Available Background To ensure patient safety and improvements in the quality of hospital care, rapid response teams (RRTs have been implemented in many countries, including Korea. The goal of an RRT is early identification and response to clinical deterioration in patients. However, there are differences in RRT systems among hospitals and limited data are available. Methods In Seoul St. Mary’s Hospital, the St. Mary’s Advanced Life Support Team was implemented in June 2013. We retrospectively reviewed the RRT activation records of 287 cases from June 2013 to December 2016. Results The median response time and median modified early warning score were 8.6 minutes (interquartile range, 5.6 to 11.6 minutes and 5.0 points (interquartile range, 4.0 to 7.0 points, respectively. Residents (35.8% and nurses (59.1% were the main activators of the RRT. Interestingly, postoperative patients account for a large percentage of the RRT activation cases (69.3%. The survival rate was 83.6% and survival was mainly associated with malignancy, Acute Physiology and Chronic Health Evaluation-II score, and the time from admission to RRT activation. RRT activation with screening showed a better outcome compared to activation via a phone call in terms of the intensive care unit admission rate and length of hospital stay after RRT activation. Conclusions Malignancy was the most important factor related to survival. In addition, RRT activation with patient screening showed a better outcome compared to activation via a phone call. Further studies are needed to determine the effective screening criteria and improve the quality of the RRT system.

  20. A conformationally defined 6-s-trans-retinoic acid isomer: synthesis, chemopreventive activity, and toxicity.

    Science.gov (United States)

    Vaezi, M F; Alam, M; Sani, B P; Rogers, T S; Simpson-Herren, L; Wille, J J; Hill, D L; Doran, T I; Brouillette, W J; Muccio, D D

    1994-12-23

    A conformationally defined retinoic acid analog (1) which contains a dimethylene bridge to maintain the 6-s-trans orientation for two terminal double bonds in the polyene chain was synthesized. A Reformatsky reaction was utilized to extend the polyene chain of the starting enone, which provided exclusively the 9Z-configuration for the intermediate aldehyde. A Horners-Emmons condensation with this aldehyde then produced retinoic acid analogs with both 9Z- and 9Z,13Z-configurations. An I2-catalyzed isomerization of the intermediate 9Z-aldehyde yielded the all-E-aldehyde, which was olefinated as above to yield the (all-E)- and (13Z)-retinoic acid analogs of 1. Each configurational isomer of 1 was evaluated for its ability to inhibit the binding of retinoic acid to CRABP (chick skin) and to inhibit the chemical induction of ornithine decarboxylase in mouse skin. In each assay (all-E)-1 was the most active isomer, and this activity was comparable to or better than that for (all-E)-retinoic acid. (all-E)-1 and (13Z)-1 were both shown to be equally effective as (13Z)-retinoic acid in suppressing the proliferation of human sebaceous cells in vitro. (all-E)-1 was further evaluated for its ability to prevent the induction of mouse skin papillomas and to induce signs of vitamin A toxicity in mice. The cancer chemopreventive activity of (all-E)-1 was comparable to that of (all-E)-retinoic acid, and the toxicity was comparable to or slightly better than that of the natural vitamin.

  1. Conformational adaptation of Asian macaque TRIMCyp directs lineage specific antiviral activity.

    Directory of Open Access Journals (Sweden)

    Laura M J Ylinen

    2010-08-01

    Full Text Available TRIMCyps are anti-retroviral proteins that have arisen independently in New World and Old World primates. All TRIMCyps comprise a CypA domain fused to the tripartite domains of TRIM5alpha but they have distinct lentiviral specificities, conferring HIV-1 restriction in New World owl monkeys and HIV-2 restriction in Old World rhesus macaques. Here we provide evidence that Asian macaque TRIMCyps have acquired changes that switch restriction specificity between different lentiviral lineages, resulting in species-specific alleles that target different viruses. Structural, thermodynamic and viral restriction analysis suggests that a single mutation in the Cyp domain, R69H, occurred early in macaque TRIMCyp evolution, expanding restriction specificity to the lentiviral lineages found in African green monkeys, sooty mangabeys and chimpanzees. Subsequent mutations have enhanced restriction to particular viruses but at the cost of broad specificity. We reveal how specificity is altered by a scaffold mutation, E143K, that modifies surface electrostatics and propagates conformational changes into the active site. Our results suggest that lentiviruses may have been important pathogens in Asian macaques despite the fact that there are no reported lentiviral infections in current macaque populations.

  2. Conformal Nets II: Conformal Blocks

    Science.gov (United States)

    Bartels, Arthur; Douglas, Christopher L.; Henriques, André

    2017-08-01

    Conformal nets provide a mathematical formalism for conformal field theory. Associated to a conformal net with finite index, we give a construction of the `bundle of conformal blocks', a representation of the mapping class groupoid of closed topological surfaces into the category of finite-dimensional projective Hilbert spaces. We also construct infinite-dimensional spaces of conformal blocks for topological surfaces with smooth boundary. We prove that the conformal blocks satisfy a factorization formula for gluing surfaces along circles, and an analogous formula for gluing surfaces along intervals. We use this interval factorization property to give a new proof of the modularity of the category of representations of a conformal net.

  3. Rapid Arc, helical tomotherapy, sliding window intensity modulated radiotherapy and three dimensional conformal radiation for localized prostate cancer: A dosimetric comparison

    Directory of Open Access Journals (Sweden)

    Rajesh A Kinhikar

    2014-01-01

    Full Text Available Objective: The objective of this study was to investigate the potential role of RapidArc (RA compared with helical tomotherapy (HT, sliding window intensity modulated radiotherapy (SW IMRT and three-dimensional conformal radiation therapy (3D CRT for localized prostate cancer. Materials and Methods: Prescription doses ranged from 60 Gy to planning target volume (PTV and 66.25 Gy for clinical target volume prostate (CTV-P over 25-30 fractions. PTV and CTV-P coverage were evaluated by conformity index (CI and homogeneity index (HI. Organ sparing comparison was done with mean doses to rectum and bladder. Results: CI 95 were 1.0 ± 0.01 (RA, 0.99 ± 0.01 (HT, 0.97 ± 0.02 (IMRT, 0.98 ± 0.02 (3D CRT for PTV and 1.0 ± 0.00 (RA, HT, SW IMRT and 3D CRT for CTV-P. HI was 0.11 ± 0.03 (RA, 0.16 ± 0.08 (HT, 0.12 ± 0.03 (IMRT, 0.06 ± 0.01 (3D CRT for PTV and 0.03 ± 0.00 (RA, 0.05 ± 0.01 (HT, 0.03 ± 0.01 (SW IMRT and 3D CRT for CTV-P. Mean dose to bladder were 23.68 ± 13.23 Gy (RA, 24.55 ± 12.51 Gy (HT, 19.82 ± 11.61 Gy (IMRT and 23.56 ± 12.81 Gy (3D CRT, whereas mean dose to rectum was 36.85 ± 12.92 Gy (RA, 33.18 ± 11.12 Gy (HT, IMRT and 38.67 ± 12.84 Gy (3D CRT. Conclusion: All studied intensity-modulated techniques yield treatment plans of significantly improved quality when compared with 3D CRT, with HT providing best organs at risk sparing and RA being the most efficient treatment option, reducing treatment time to 1.45-3.7 min and monitor unit to <400 for a 2 Gy fraction.

  4. The R163K Mutant of Human Thymidylate Synthase Is Stabilized in an Active Conformation: Structural Asymmetry and Reactivity of Cysteine 195

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, Lydia M.; Lovelace, Leslie L.; Lebioda, Lukasz (SC)

    2008-06-16

    Loop 181-197 of human thymidylate synthase (hTS) populates two conformational states. In the first state, Cys195, a residue crucial for catalytic activity, is in the active site (active conformer); in the other conformation, it is about 10 {angstrom} away, outside the active site (inactive conformer). We have designed and expressed an hTS variant, R163K, in which the inactive conformation is destabilized. The activity of this mutant is 33% higher than that of wt hTS, suggesting that at least one-third of hTS populates the inactive conformer. Crystal structures of R163K in two different crystal forms, with six and two subunits per asymmetric part of the unit cells, have been determined. All subunits of this mutant are in the active conformation while wt hTS crystallizes as the inactive conformer in similar mother liquors. The structures show differences in the environment of catalytic Cys195, which correlate with Cys195 thiol reactivity, as judged by its oxidation state. Calculations show that the molecular electrostatic potential at Cys195 differs between the subunits of the dimer. One of the dimers is asymmetric with a phosphate ion bound in only one of the subunits. In the absence of the phosphate ion, that is in the inhibitor-free enzyme, the tip of loop 47-53 is about 11 {angstrom} away from the active site.

  5. Rapid assessment of disaster damage using social media activity

    Science.gov (United States)

    Kryvasheyeu, Yury; Chen, Haohui; Obradovich, Nick; Moro, Esteban; Van Hentenryck, Pascal; Fowler, James; Cebrian, Manuel

    2016-01-01

    Could social media data aid in disaster response and damage assessment? Countries face both an increasing frequency and an increasing intensity of natural disasters resulting from climate change. During such events, citizens turn to social media platforms for disaster-related communication and information. Social media improves situational awareness, facilitates dissemination of emergency information, enables early warning systems, and helps coordinate relief efforts. In addition, the spatiotemporal distribution of disaster-related messages helps with the real-time monitoring and assessment of the disaster itself. We present a multiscale analysis of Twitter activity before, during, and after Hurricane Sandy. We examine the online response of 50 metropolitan areas of the United States and find a strong relationship between proximity to Sandy’s path and hurricane-related social media activity. We show that real and perceived threats, together with physical disaster effects, are directly observable through the intensity and composition of Twitter’s message stream. We demonstrate that per-capita Twitter activity strongly correlates with the per-capita economic damage inflicted by the hurricane. We verify our findings for a wide range of disasters and suggest that massive online social networks can be used for rapid assessment of damage caused by a large-scale disaster. PMID:27034978

  6. Rapid assessment of disaster damage using social media activity.

    Science.gov (United States)

    Kryvasheyeu, Yury; Chen, Haohui; Obradovich, Nick; Moro, Esteban; Van Hentenryck, Pascal; Fowler, James; Cebrian, Manuel

    2016-03-01

    Could social media data aid in disaster response and damage assessment? Countries face both an increasing frequency and an increasing intensity of natural disasters resulting from climate change. During such events, citizens turn to social media platforms for disaster-related communication and information. Social media improves situational awareness, facilitates dissemination of emergency information, enables early warning systems, and helps coordinate relief efforts. In addition, the spatiotemporal distribution of disaster-related messages helps with the real-time monitoring and assessment of the disaster itself. We present a multiscale analysis of Twitter activity before, during, and after Hurricane Sandy. We examine the online response of 50 metropolitan areas of the United States and find a strong relationship between proximity to Sandy's path and hurricane-related social media activity. We show that real and perceived threats, together with physical disaster effects, are directly observable through the intensity and composition of Twitter's message stream. We demonstrate that per-capita Twitter activity strongly correlates with the per-capita economic damage inflicted by the hurricane. We verify our findings for a wide range of disasters and suggest that massive online social networks can be used for rapid assessment of damage caused by a large-scale disaster.

  7. Large loop conformation sampling using the activation relaxation technique, ART-nouveau method.

    Science.gov (United States)

    St-Pierre, Jean-François; Mousseau, Normand

    2012-07-01

    We present an adaptation of the ART-nouveau energy surface sampling method to the problem of loop structure prediction. This method, previously used to study protein folding pathways and peptide aggregation, is well suited to the problem of sampling the conformation space of large loops by targeting probable folding pathways instead of sampling exhaustively that space. The number of sampled conformations needed by ART nouveau to find the global energy minimum for a loop was found to scale linearly with the sequence length of the loop for loops between 8 and about 20 amino acids. Considering the linear scaling dependence of the computation cost on the loop sequence length for sampling new conformations, we estimate the total computational cost of sampling larger loops to scale quadratically compared to the exponential scaling of exhaustive search methods. Copyright © 2012 Wiley Periodicals, Inc.

  8. Antagonist-perturbation mechanism for activation function-2 fixed motifs: active conformation and docking mode of retinoid X receptor antagonists

    Science.gov (United States)

    Tsuji, Motonori

    2017-06-01

    HX531, which contains a dibenzodiazepine skeleton, is one of the first retinoid X receptor (RXR) antagonists. Functioning via RXR-PPARγ heterodimer, this compound is receiving a lot of attention as a therapeutic drug candidate for diabetic disease controlling differentiation of adipose tissue. However, the active conformation of HX531 for RXRs is not well established. In the present study, quantum mechanics calculations and molecular mechanical docking simulations were carried out to precisely study the docking mode of HX531 with the human RXRα ligand-binding domain, as well as to provide a new approach to drug design using a structure-based perspective. It was suggested that HX531, which has the R configuration for the bent dibenzodiazepine plane together with the equatorial configuration for the N-methyl group attached to the nitrogen atom in the seven-membered diazepine ring, is a typical activation function-2 (AF-2) fixed motif perturbation type antagonist, which destabilizes the formation of AF-2 fixed motifs. On the other hand, the docking simulations supported the experimental result that LG100754 is an RXR homodimer antagonist and an RXR heterodimer agonist.

  9. A rapid search for the counterpart to an active magnetar

    Science.gov (United States)

    Levan, Andrew

    2016-10-01

    We propose to obtain a fast response observation of a magnetar undergoing an active period. Utilizing rapid, deep, diffraction limited observations with WFC3 we will maximize the chances of obtaining the IR detection of the magnetar. This in turn yields unique constraints on emission mechanisms, enables the measurement of dynamics (e.g. via proper motion) and can associate the magnetar with a given structure (e.g. young cluster or supernova remnant) in the galaxy. The association with a cluster provides means of measuring the stellar age, in turn informing the stellar properties (e.g. mass) of the magnetar progenitors. We have demonstrated the success of this approach with the detection of the counterpart of SGR 1935+2154 with a magnitude (during bursting activity) of F140W(AB) 25.5, a level extremely challenging to detect variability in from the ground, requiring multiple nights of adaptive optics imaging in typical conditions. Indeed, our observations will be senstive to counterparts significantly fainter than it is possible to detect from any ground based observatory. These observations will allow us to break through the observational barrier that has so far prevented us from detecting counterparts to more than two-thirds of magnetar candidates. With these observations we will construct a fuller picture of magnetars, the routes to their creation, and their role as cosmic engines across the Universe.

  10. Conformal house

    DEFF Research Database (Denmark)

    Ryttov, Thomas Aaby; Sannino, Francesco

    2010-01-01

    fixed point. As a consistency check we recover the previously investigated bounds of the conformal windows when restricting to a single matter representation. The earlier conformal windows can be imagined to be part now of the new conformal house. We predict the nonperturbative anomalous dimensions...... at the infrared fixed points. We further investigate the effects of adding mass terms to the condensates on the conformal house chiral dynamics and construct the simplest instanton induced effective Lagrangian terms...

  11. Jatrophidin I, a cyclic peptide from Brazilian Jatropha curcas L.: isolation, characterization, conformational studies and biological activity.

    Science.gov (United States)

    Altei, Wanessa F; Picchi, Douglas G; Abissi, Barbara M; Giesel, Guilherme M; Flausino, Otavio; Reboud-Ravaux, Michèle; Verli, Hugo; Crusca, Edson; Silveira, Edilberto R; Cilli, Eduardo M; Bolzani, Vanderlan S

    2014-11-01

    A cyclic peptide, jatrophidin I, was isolated from the latex of Jatropha curcas L. Its structure was elucidated by extensive 2D NMR spectroscopic analysis, with additional conformational studies performed using Molecular Dynamics/Simulated Annealing (MD/SA). Jatrophidin I had moderate protease inhibition activity when compared with pepstatin A; however, the peptide was inactive in antimalarial, cytotoxic and antioxidant assays. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Rapid Assessment Medical Support (RAMS) for active shooter incidents.

    Science.gov (United States)

    Mechem, C Crawford; Bossert, Richard; Baldini, Christopher

    2015-01-01

    This country has witnessed a steady increase in the number of active shooter incidents in recent years. The traditional emergency medical services (EMS) response to such incidents has been to stage at a safe distance until the scene has been secured by law enforcement. Such an approach may lead to unnecessary delays in medical care and potentially needless loss of life. To address this issue locally, the Philadelphia Fire Department (PFD) and the Philadelphia Police Department (PPD) collaborated to develop the Rapid Assessment Medical Support (RAMS) program. All PFD paramedics have been equipped and trained to move with PPD officers into a scene that has been cleared by police but not yet secured in order to initiate emergency care, with an emphasis on hemorrhage control. Patients are then extracted to awaiting EMS resources in the cold zone. The history behind the program and the challenges and obstacles that had to be addressed in its development are described. These included initial and ongoing training and funding sources; buy-in from risk management, labor, and the individual providers; whether only paramedics should be included in the RAMS program or if the PFD's firefighter-EMTs should be included as well; the potential for mission creep as police recognized the value of this asset and its potential application to other scenarios; and how to involve the many nonmunicipal ambulance services that are not involved in the routine operation of Philadelphia's 9-1-1 system. To date, RAMS teams have been activated on multiple occasions, but fortunately the incidents were resolved without injury or loss of life. However, the program provides another valuable tool with which the City of Philadelphia can respond should another active shooter incident occur.

  13. Distinct conformational stability and functional activity of four highly homologous endonuclease colicins

    NARCIS (Netherlands)

    Bremer, van den E.T.J.; Keeble, A.H.; Jiskoot, W.; Spelbrink, R.E.J.; Maier, C.S.; Hoek, van A.; Visser, A.J.W.G.; James, R.; Moore, G.R.; Kleanthous, C.; Heck, A.J.R.

    2004-01-01

    The family of conserved colicin DNases E2, E7, E8, and E9 are microbial toxins that kill bacteria through random degradation of the chromosomal DNA. In the present work, we compare side by side the conformational stabilities of these four highly homologous colicin DNases. Our results indicate that

  14. The Conformation of Bound GMPPNP Suggests a Mechanism for Gating the Active Site of the SRP GTPase

    Energy Technology Data Exchange (ETDEWEB)

    Padmanabhan, S.; Freymann, D. (NWU)

    2010-03-08

    The signal recognition particle (SRP) is a phylogenetically conserved ribonucleoprotein that mediates cotranslational targeting of secreted and membrane proteins to the membrane. Targeting is regulated by GTP binding and hydrolysis events that require direct interaction between structurally homologous 'NG' GTPase domains of the SRP signal recognition subunit and its membrane-associated receptor, SR{alpha}. Structures of both the apo and GDP bound NG domains of the prokaryotic SRP54 homolog, Ffh, and the prokaryotic receptor homolog, FtsY, have been determined. The structural basis for the GTP-dependent interaction between the two proteins, however, remains unknown. We report here two structures of the NG GTPase of Ffh from Thermus aquaticus bound to the nonhydrolyzable GTP analog GMPPNP. Both structures reveal an unexpected binding mode in which the {beta}-phosphate is kinked away from the binding site and magnesium is not bound. Binding of the GTP analog in the canonical conformation found in other GTPase structures is precluded by constriction of the phosphate binding P loop. The structural difference between the Ffh complex and other GTPases suggests a specific conformational change that must accompany movement of the nucleotide from an inactive to an active binding mode. Conserved side chains of the GTPase sequence motifs unique to the SRP subfamily may function to gate formation of the active GTP bound conformation. Exposed hydrophobic residues provide an interaction surface that may allow regulation of the GTP binding conformation, and thus activation of the GTPase, during the association of SRP with its receptor.

  15. Conformational Changes That Coordinate the Activity of BamA and BamD Allowing β-Barrel Assembly.

    Science.gov (United States)

    McCabe, Anne L; Ricci, Dante; Adetunji, Modupe; Silhavy, Thomas J

    2017-10-15

    Most integral outer membrane proteins (OMPs) of Gram-negative bacteria, such as Escherichia coli, assume a β-barrel structure. The β-barrel assembly machine (Bam), a five-member complex composed of β-barrel OMP BamA and four associated lipoproteins, BamB, BamC, BamD, and BamE, folds and inserts OMPs into the outer membrane. The two essential proteins BamA and BamD interact to stabilize two subcomplexes, BamAB and BamCDE, and genetic and structural evidence suggests that interactions between BamA and BamD occur via an electrostatic interaction between a conserved aspartate residue in a periplasmic domain of BamA and a conserved arginine in BamD. In this work, we characterize charge-change mutations at these key BamA and BamD residues and nearby charged residues in BamA with respect to OMP assembly and Bam complex stability. We show that Bam complex stability does not correlate with function, that BamA and BamD must adopt at least two active conformational states during OMP assembly, and that these charged residues are not required for function. Rather, these charged residues are important for coordinating the activities of BamA and BamD to allow efficient OMP assembly. We present a model of OMP assembly wherein recognition and binding of unfolded OMP substrate by BamA and BamD induce a signaling interaction between the two proteins, causing conformational changes necessary for the assembly reaction to proceed. By analogy to signal sequence recognition by SecYEG, we believe these BamA-BamD interactions ensure that both substrate and complex are competent for OMP assembly before the assembly reaction commences.IMPORTANCE Conformational changes in the proteins of the β-barrel assembly machine (Bam complex) are associated with the folding and assembly of outer membrane proteins (OMPs) in Gram-negative bacteria. We show that electrostatic interactions between the two essential proteins BamA and BamD coordinate conformational changes upon binding of unfolded substrate

  16. Conformational changes in guanylate cyclase-activating protein 1 induced by Ca2+ and N-terminal fatty acid acylation.

    Science.gov (United States)

    Orban, Tivadar; Bereta, Grzegorz; Miyagi, Masaru; Wang, Benlian; Chance, Mark R; Sousa, Marcelo Carlos; Palczewski, Krzysztof

    2010-01-13

    Neuronal Ca(2+) sensors (NCS) are high-affinity Ca(2+)-binding proteins critical for regulating a vast range of physiological processes. Guanylate cyclase-activating proteins (GCAPs) are members of the NCS family responsible for activating retinal guanylate cyclases (GCs) at low Ca(2+) concentrations, triggering synthesis of cGMP and recovery of photoreceptor cells to the dark-adapted state. Here we use amide hydrogen-deuterium exchange and radiolytic labeling, and molecular dynamics simulations to study conformational changes induced by Ca(2+) and modulated by the N-terminal myristoyl group. Our data on the conformational dynamics of GCAP1 in solution suggest that Ca(2+) stabilizes the protein but induces relatively small changes in the domain structure; however, loss of Ca(+2) mediates a significant global relaxation and movement of N- and C-terminal domains. This model and the previously described "calcium-myristoyl switch" proposed for recoverin indicate significant diversity in conformational changes among these highly homologous NCS proteins with distinct functions.

  17. Modulation of constitutive activity and signaling bias of the ghrelin receptor by conformational constraint in the second extracellular loop

    DEFF Research Database (Denmark)

    Mokrosinski, Jacek; Frimurer, Thomas M; Sivertsen, Bjoern

    2012-01-01

    Based on a rare, natural Glu for Ala204(C+6) variant located six residues after the conserved Cys residue in extracellular loop 2 (ECL2b) associated with selective elimination of the high constitutive signaling of the ghrelin receptor, this loop was subjected to a detailed structure functional....... Moreover, the constitutive activity of the receptor was inhibited by Zn(2+) binding in an engineered metal-ion site stabilizing an a-helical conformation of this loop segment. It is concluded that the high constitutive activity of the ghrelin receptor is dependent upon flexibility in the C-terminal segment...

  18. Crystallization and activation of silicon by microwave rapid annealing

    Science.gov (United States)

    Kimura, Shunsuke; Ota, Kosuke; Hasumi, Masahiko; Suzuki, Ayuta; Ushijima, Mitsuru; Sameshima, Toshiyuki

    2016-07-01

    A combination of the carbon-powder absorber with microwave irradiation is proposed as a rapid heat method. 2-μm-diameter carbon powders with a packing density of 0.08 effectively absorbed 2.45 GHz 1000-W-microwave and heated themselves to 1163 °C for 26 s. The present heat treatment recrystallized n-type crystalline silicon surfaces implanted with 1.0 × 10^{15}hbox {-cm}^{-2}-boron and phosphorus atoms with crystalline volume ratios of 0.99 and 0.93, respectively, by microwave irradiation at 1000 W for 20 s. Activation and carrier generation were simultaneously achieved with a sheet resistivity of 62 Ω / hbox {sq}. A high photo-induced-carrier effective lifetime of 1.0 × 10^{-4} s was also achieved. Typical electrical current-rectified characteristic and solar cell characteristic with an efficiency of 12.1 % under 100-mW/cm2-air-mass-1.5 illumination were obtained. Moreover, heat treatment with microwave irradiation at 1000 W for 22 s successfully crystallized silicon thin films with thicknesses ranging from 2.4 to 50 nm formed on quartz substrates. Nano-crystalline cluster structure with a high volume ratio of 50 % was formed in the 1.8-nm (initial 2.4-nm)-thick silicon films. Photoluminescence around 1.77 eV was observed for the 1.8-nm-thick silicon films annealed at 260 °C in 1.3 × 106-Pa-H2O-vapor for 3 h after the microwave heating.

  19. Synthesis of selenium-containing Artemisia sphaerocephala polysaccharides: Solution conformation and anti-tumor activities in vitro.

    Science.gov (United States)

    Wang, Junlong; Li, Qingyao; Bao, Aijuan; Liu, Xiurong; Zeng, Junyuan; Yang, Xiaopin; Yao, Jian; Zhang, Ji; Lei, Ziqiang

    2016-11-05

    It has been reported in our previous work that selenized Artemisia sphaerocephala polysaccharides (SeASPs) with the Se content range of 168-1703μg/g were synthesized by using Na2SeO3/HNO3/BaCl2 system. In the present work, the solution property of SeASP was studied by using size exclusion chromatography combined with multi angle laser light scattering (SEC-MALLS). A decrease in df values indicated that SeASPs with different conformational features that were highly dependent on MW. SeASPs exhibited a more rigid conformation (df value of 1.29-1.52) in low molecular weight range (MW of 1.026-1.426×10(4)g/mol) and compact spherical conformation in high molecular weight range (MW of 2.268-4.363×10(4)g/mol). It could be due to the degradation of polysaccharide chains in HNO3, which was supported in monosaccharide composition analysis. Congo red (CR) spectrophotometric method and atomic force microscopy (AFM) results also confirmed the conformational transition and the evidence on the shape of the rigid chains. In vitro anti-tumor assays, SeASP2 displayed greater anti-proliferative effects against three tumor cell lines (hepatocellular carcinoma HepG-2 cells, lung adenocarcinom A549 cells and cervical squamous carcinoma Hela cells) in a dose-dependent manner. This suggested that selenylation could significantly enhance the anti-tumor activities of polysaccharide derivatives in vitro. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Transportation Conformity

    Science.gov (United States)

    This section provides information on: current laws, regulations and guidance, policy and technical guidance, project-level conformity, general information, contacts and training, adequacy review of SIP submissions

  1. Relationship between Oversulfation and Conformation of Low and High Molecular Weight Fucoidans and Evaluation of Their in Vitro Anticancer Activity

    Directory of Open Access Journals (Sweden)

    Myoung Lae Cho

    2010-12-01

    Full Text Available Low and high molecular weight fucoidans (F5-30K and F>30K were chemically modified through the addition of sulfate groups, and the effect of oversulfation on the in vitro anticancer activity was investigated. After the addition of sulfate groups, a considerable increase of 35.5 to 56.8% was observed in the sulfate content of the F5-30K fraction, while the sulfate content of the F>30K fraction increased to a lesser extent (from 31.7 to 41.2%. Significant differences in anticancer activity were observed between the oversulfated F5–30K and F>30K fractions, with activities of 37.3–68.0% and 20.6–35.8%, respectively. This variation in the anticancer activity of oversulfated fucoidan derivatives was likely due to differences in their sulfate content. The results suggest that the molecular conformation of these molecules is closely related to the extent of sulfation in the fucan backbones and that the sulfates are preferably substituted when the fucoidan polymers are in a loose molecular conformation.

  2. Structural and dynamic insights into the role of conformational switching in the nuclease activity of theXanthomonas albilineansCas2 in CRISPR-mediated adaptive immunity.

    Science.gov (United States)

    Ka, Donghyun; Hong, Suji; Jeong, Ugeene; Jeong, Migyeong; Suh, Nayoung; Suh, Jeong-Yong; Bae, Euiyoung

    2017-09-01

    Clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) proteins constitute a microbial, adaptive immune system countering invading nucleic acids. Cas2 is a universal Cas protein found in all types of CRISPR-Cas systems, and its role is implicated in new spacer acquisition into CRISPR loci. In subtype I-C CRISPR-Cas systems, Cas2 proteins are metal-dependent double-stranded DNA (dsDNA) nucleases, and a pH-dependent conformational transition has been proposed as a prerequisite for catalytic action. Here, we report the crystal structure of Xanthomonas albilineans Cas2 (XaCas2) and provide experimental evidence of a pH-dependent conformational change during functional activation. XaCas2 crystallized at an acidic pH represented a catalytically inactive conformational state in which two Asp8 residues were too far apart to coordinate a single catalytic metal ion. Consistently, XaCas2 exhibited dsDNA nuclease activity only under neutral and basic conditions. Despite the overall structural similarity of the two protomers, significant conformational heterogeneity was evident in the putative hinge regions, suggesting that XaCas2 engages in hinge-bending conformational switching. The presence of a Trp residue in the hinge region enabled the investigation of hinge dynamics by fluorescence spectroscopy. The pH dependence of the fluorescence intensity overlapped precisely with that of nuclease activity. Mutational analyses further suggested that conformational activation proceeded via a rigid-body hinge-bending motion as both D8E and hinge mutations significantly reduced nuclease activity. Together, our results reveal strong correlations between the conformational states, catalytic activity, and hinge dynamics of XaCas2, and provide structural and dynamic insights into the conformational activation of the nuclease function of Cas2.

  3. Cosmological Perturbations in Conformal Gravity

    CERN Document Server

    Mannheim, Philip D

    2011-01-01

    We present the first steps needed for an analysis of the perturbations that occur in the cosmology associated with the conformal gravity theory. We discuss the implications of conformal invariance for perturbative coordinate gauge choices, and show that in the conformal theory the trace of the metric fluctuation kinematically decouples from the first-order gravitational fluctuation equations. We determine the equations that describe first-order metric fluctuations around the illustrative conformally flat de Sitter background. Via a conformal transformation we show that such fluctuations can be constructed from fluctuations around a flat background, even though the fluctuations themselves are associated with a perturbative geometry that is not itself conformal to flat. We extend the analysis to fluctuations around other cosmologically relevant backgrounds, such as the conformally-flat Robertson-Walker background, and find tensor fluctuations that grow far more rapidly than those that occur in the analogous sta...

  4. Achieving a Graded Immune Response: BTK Adopts a Range of Active/Inactive Conformations Dictated by Multiple Interdomain Contacts.

    Science.gov (United States)

    Joseph, Raji E; Wales, Thomas E; Fulton, D Bruce; Engen, John R; Andreotti, Amy H

    2017-10-03

    Capturing the functionally relevant forms of dynamic, multidomain proteins is extremely challenging. Bruton's tyrosine kinase (BTK), a kinase essential for B and mast cell function, has stubbornly resisted crystallization in its full-length form. Here, nuclear magnetic resonance and hydrogen-deuterium exchange mass spectrometry show that BTK adopts a closed conformation in dynamic equilibrium with open, active conformations. BTK lacks the phosphotyrosine regulatory tail of the SRC kinases, yet nevertheless achieves a phosphotyrosine-independent C-terminal latch. The unique proline-rich region is an internal "on" switch pushing the autoinhibited kinase toward its active state. Newly identified autoinhibitory contacts in the BTK pleckstrin homology domain are sensitive to phospholipid binding, which induces large-scale allosteric changes. The multiplicity of these regulatory contacts suggests a clear mechanism for gradual or "analog" kinase activation as opposed to a binary "on/off" switch. The findings illustrate how previously modeled information for recalcitrant full-length proteins can be expanded and validated with a convergent multidisciplinary experimental approach. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Space and Time Resolved Detection of Platelet Activation and von Willebrand Factor Conformational Changes in Deep Suspensions.

    Science.gov (United States)

    Biasetti, Jacopo; Sampath, Kaushik; Cortez, Angel; Azhir, Alaleh; Gilad, Assaf A; Kickler, Thomas S; Obser, Tobias; Ruggeri, Zaverio M; Katz, Joseph

    2017-01-01

    Tracking cells and proteins' phenotypic changes in deep suspensions is critical for the direct imaging of blood-related phenomena in in vitro replica of cardiovascular systems and blood-handling devices. This paper introduces fluorescence imaging techniques for space and time resolved detection of platelet activation, von Willebrand factor (VWF) conformational changes, and VWF-platelet interaction in deep suspensions. Labeled VWF, platelets, and VWF-platelet strands are suspended in deep cuvettes, illuminated, and imaged with a high-sensitivity EM-CCD camera, allowing detection using an exposure time of 1 ms. In-house postprocessing algorithms identify and track the moving signals. Recombinant VWF-eGFP (rVWF-eGFP) and VWF labeled with an FITC-conjugated polyclonal antibody are employed. Anti-P-Selectin FITC-conjugated antibodies and the calcium-sensitive probe Indo-1 are used to detect activated platelets. A positive correlation between the mean number of platelets detected per image and the percentage of activated platelets determined through flow cytometry is obtained, validating the technique. An increase in the number of rVWF-eGFP signals upon exposure to shear stress demonstrates the technique's ability to detect breakup of self-aggregates. VWF globular and unfolded conformations and self-aggregation are also observed. The ability to track the size and shape of VWF-platelet strands in space and time provides means to detect pro- and antithrombotic processes.

  6. Rapid neurogenesis through transcriptional activation in human stem cells.

    Science.gov (United States)

    Busskamp, Volker; Lewis, Nathan E; Guye, Patrick; Ng, Alex H M; Shipman, Seth L; Byrne, Susan M; Sanjana, Neville E; Murn, Jernej; Li, Yinqing; Li, Shangzhong; Stadler, Michael; Weiss, Ron; Church, George M

    2014-11-17

    Advances in cellular reprogramming and stem cell differentiation now enable ex vivo studies of human neuronal differentiation. However, it remains challenging to elucidate the underlying regulatory programs because differentiation protocols are laborious and often result in low neuron yields. Here, we overexpressed two Neurogenin transcription factors in human-induced pluripotent stem cells and obtained neurons with bipolar morphology in 4 days, at greater than 90% purity. The high purity enabled mRNA and microRNA expression profiling during neurogenesis, thus revealing the genetic programs involved in the rapid transition from stem cell to neuron. The resulting cells exhibited transcriptional, morphological and functional signatures of differentiated neurons, with greatest transcriptional similarity to prenatal human brain samples. Our analysis revealed a network of key transcription factors and microRNAs that promoted loss of pluripotency and rapid neurogenesis via progenitor states. Perturbations of key transcription factors affected homogeneity and phenotypic properties of the resulting neurons, suggesting that a systems-level view of the molecular biology of differentiation may guide subsequent manipulation of human stem cells to rapidly obtain diverse neuronal types. © 2014 The Authors. Published under the terms of the CC BY 4.0 license.

  7. Self-objectification, feminist activism and conformity to feminine norms among female vegetarians, semi-vegetarians, and non-vegetarians.

    Science.gov (United States)

    Brinkman, Britney G; Khan, Aliya; Edner, Benjamin; Rosén, Lee A

    2014-01-01

    Recent research has suggested that vegetarians may be at an increased risk for developing disordered eating or body image issues when compared to non-vegetarians. However, the results of such studies are mixed, and no research has explored potential connections between vegetarianism and self-objectification. In the current study, the authors examine factors that predicted body surveillance, body shame, and appearance control beliefs; three aspects of self-objectification. Surveys were completed by 386 women from the United States who were categorized as vegetarian, semi-vegetarian, or non-vegetarian. The three groups differed regarding dietary motivations, levels of feminist activism, and body shame, but did not differ on their conformity to feminine norms. While conformity to feminine norms predicted body surveillance and body shame levels among all three groups of women, feminist activism predicted appearance control beliefs among non-vegetarians only. These findings suggest that it is important for researchers and clinicians to distinguish among these three groups when examining the relationship between vegetarianism and self-objectification. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. General Conformity

    Science.gov (United States)

    The General Conformity requirements ensure that the actions taken by federal agencies in nonattainment and maintenance areas do not interfere with a state’s plans to meet national standards for air quality.

  9. Conformal Infinity

    Directory of Open Access Journals (Sweden)

    Frauendiener Jörg

    2000-08-01

    Full Text Available The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, ``conformal infinity'' is related with almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved out of physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation and how it lends itself very naturally to solve radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

  10. Conformal Infinity

    Directory of Open Access Journals (Sweden)

    Frauendiener Jörg

    2004-01-01

    Full Text Available The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, 'conformal infinity' is related to almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved from physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation, and how it lends itself very naturally to the solution of radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

  11. Direct electrical control of IgG conformation and functional activity at surfaces

    Science.gov (United States)

    Ghisellini, Paola; Caiazzo, Marialuisa; Alessandrini, Andrea; Eggenhöffner, Roberto; Vassalli, Massimo; Facci, Paolo

    2016-11-01

    We have devised a supramolecular edifice involving His-tagged protein A and antibodies to yield surface immobilized, uniformly oriented, IgG-type, antibody layers with Fab fragments exposed off an electrode surface. We demonstrate here that we can affect the conformation of IgGs, likely pushing/pulling electrostatically Fab fragments towards/from the electrode surface. A potential difference between electrode and solution acts on IgGs’ charged aminoacids modulating the accessibility of the specific recognition regions of Fab fragments by antigens in solution. Consequently, antibody-antigen affinity is affected by the sign of the applied potential: a positive potential enables an effective capture of antigens; a negative one pulls the fragments towards the electrode, where steric hindrance caused by neighboring molecules largely hampers the capture of antigens. Different experimental techniques (electrochemical quartz crystal microbalance, electrochemical impedance spectroscopy, fluorescence confocal microscopy and electrochemical atomic force spectroscopy) were used to evaluate binding kinetics, surface coverage, effect of the applied electric field on IgGs, and role of charged residues on the phenomenon described. These findings expand the concept of electrical control of biological reactions and can be used to gate electrically specific recognition reactions with impact in biosensors, bioactuators, smart biodevices, nanomedicine, and fundamental studies related to chemical reaction kinetics.

  12. A bioluminescent caspase-1 activity assay rapidly monitors inflammasome activation in cells.

    Science.gov (United States)

    O'Brien, Martha; Moehring, Danielle; Muñoz-Planillo, Raúl; Núñez, Gabriel; Callaway, Justin; Ting, Jenny; Scurria, Mike; Ugo, Tim; Bernad, Laurent; Cali, James; Lazar, Dan

    2017-08-01

    Inflammasomes are protein complexes induced by diverse inflammatory stimuli that activate caspase-1, resulting in the processing and release of cytokines, IL-1β and IL-18, and pyroptosis, an immunogenic form of cell death. To provide a homogeneous method for detecting caspase-1 activity, we developed a bioluminescent, plate-based assay that combines a substrate, Z-WEHD-aminoluciferin, with a thermostable luciferase in an optimized lytic reagent added directly to cultured cells. Assay specificity for caspase-1 is conferred by inclusion of a proteasome inhibitor in the lytic reagent and by use of a caspase-1 inhibitor to confirm activity. This approach enables a specific and rapid determination of caspase-1 activation. Caspase-1 activity is stable in the reagent thereby providing assay convenience and flexibility. Using this assay system, caspase-1 activation has been determined in THP-1 cells following treatment with α-hemolysin, LPS, nigericin, gramicidin, MSU, R848, Pam3CSK4, and flagellin. Caspase-1 activation has also been demonstrated in treated J774A.1 mouse macrophages, bone marrow-derived macrophages (BMDMs) from mice, as well as in human primary monocytes. Caspase-1 activity was not detected in treated BMDMs derived from Casp1-/- mice, further confirming the specificity of the assay. Caspase-1 activity can be measured directly in cultured cells using the lytic reagent, or caspase-1 activity released into medium can be monitored by assay of transferred supernatant. The caspase-1 assay can be multiplexed with other assays to monitor additional parameters from the same cells, such as IL-1β release or cell death. The caspase-1 assay in combination with a sensitive real-time monitor of cell death allows one to accurately establish pyroptosis. This assay system provides a rapid, convenient, and flexible method to specifically and quantitatively monitor caspase-1 activation in cells in a plate-based format. This will allow a more efficient and effective

  13. Ensemble perspective for catalytic promiscuity: calorimetric analysis of the active site conformational landscape of a detoxification enzyme.

    Science.gov (United States)

    Honaker, Matthew T; Acchione, Mauro; Sumida, John P; Atkins, William M

    2011-12-09

    Enzymological paradigms have shifted recently to acknowledge the biological importance of catalytic promiscuity. However, catalytic promiscuity is a poorly understood property, and no thermodynamic treatment has described the conformational landscape of promiscuous versus substrate-specific enzymes. Here, two structurally similar glutathione transferase (GST, glutathione S-transferase) isoforms with high specificity or high promiscuity are compared. Differential scanning calorimetry (DSC) indicates a reversible low temperature transition for the promiscuous GSTA1-1 that is not observed with substrate-specific GSTA4-4. This transition is assigned to rearrangement of the C terminus at the active site of GSTA1-1 based on the effects of ligands and mutations. Near-UV and far-UV circular dichroism indicate that this transition is due to repacking of tertiary contacts with the remainder of the subunit, rather than "unfolding" of the C terminus per se. Analysis of the DSC data using a modified Landau theory indicates that the local conformational landscape of the active site of GSTA1-1 is smooth, with barrierless transitions between states. The partition function of the C-terminal states is a broad unimodal distribution at all temperatures within this DSC transition. In contrast, the remainder of the GSTA1-1 subunit and the GSTA4-4 protein exhibit folded and unfolded macrostates with a significant energy barrier separating them. Their partition function includes a sharp unimodal distribution of states only at temperatures that yield either folded or unfolded macrostates. At intermediate temperatures the partition function includes a bimodal distribution. The barrierless rearrangement of the GSTA1-1 active site within a local smooth energy landscape suggests a thermodynamic basis for catalytic promiscuity.

  14. The membrane anchor of the transcriptional activator SREBP is characterized by intrinsic conformational flexibility

    Science.gov (United States)

    Linser, Rasmus; Salvi, Nicola; Briones, Rodolfo; Rovó, Petra; de Groot, Bert L.; Wagner, Gerhard

    2015-01-01

    Regulated intramembrane proteolysis (RIP) is a conserved mechanism crucial for numerous cellular processes, including signaling, transcriptional regulation, axon guidance, cell adhesion, cellular stress responses, and transmembrane protein fragment degradation. Importantly, it is relevant in various diseases including Alzheimer’s disease, cardiovascular diseases, and cancers. Even though a number of structures of different intramembrane proteases have been solved recently, fundamental questions concerning mechanistic underpinnings of RIP and therapeutic interventions remain. In particular, this includes substrate recognition, what properties render a given substrate amenable for RIP, and how the lipid environment affects the substrate cleavage. Members of the sterol regulatory element-binding protein (SREBP) family of transcription factors are critical regulators of genes involved in cholesterol/lipid homeostasis. After site-1 protease cleavage of the inactive SREBP transmembrane precursor protein, RIP of the anchor intermediate by site-2 protease generates the mature transcription factor. In this work, we have investigated the labile anchor intermediate of SREBP-1 using NMR spectroscopy. Surprisingly, NMR chemical shifts, site-resolved solvent exposure, and relaxation studies show that the cleavage site of the lipid-signaling protein intermediate bears rigid α-helical topology. An evolutionary conserved motif, by contrast, interrupts the secondary structure ∼9–10 residues C-terminal of the scissile bond and acts as an inducer of conformational flexibility within the carboxyl-terminal transmembrane region. These results are consistent with molecular dynamics simulations. Topology, stability, and site-resolved dynamics data suggest that the cleavage of the α-helical substrate in the case of RIP may be associated with a hinge motion triggered by the molecular environment. PMID:26392539

  15. Conformational entropic maps of functional coupling domains in GPCR activation: A case study with beta2 adrenergic receptor

    Science.gov (United States)

    Liu, Fan; Abrol, Ravinder; Goddard, William, III; Dougherty, Dennis

    2014-03-01

    Entropic effect in GPCR activation is poorly understood. Based on the recent solved structures, researchers in the GPCR structural biology field have proposed several ``local activating switches'' that consisted of a few number of conserved residues, but have long ignored the collective dynamical effect (conformational entropy) of a domain comprised of an ensemble of residues. A new paradigm has been proposed recently that a GPCR can be viewed as a composition of several functional coupling domains, each of which undergoes order-to-disorder or disorder-to-order transitions upon activation. Here we identified and studied these functional coupling domains by comparing the local entropy changes of each residue between the inactive and active states of the β2 adrenergic receptor from computational simulation. We found that agonist and G-protein binding increases the heterogeneity of the entropy distribution in the receptor. This new activation paradigm and computational entropy analysis scheme provides novel ways to design functionally modified mutant and identify new allosteric sites for GPCRs. The authors thank NIH and Sanofi for funding this project.

  16. Correlation of Conformational Changes and Protein Degradation with Loss of Lysozyme Activity Due to Chlorine Dioxide Treatment.

    Science.gov (United States)

    Ooi, Beng Guat; Branning, Sharon Alyssa

    2017-06-01

    Chlorine dioxide (ClO2) is a potent oxidizing agent used for the treatment of drinking water and decontamination of facilities and equipment. The purpose of this research is to elucidate the manner in which ClO2 destroys proteins by studying the effects of ClO2 on lysozyme. The degree of enzyme activity lost can be correlated to the treatment time and levels of the ClO2 used. Lysozyme activity was drastically reduced to 45.3% of original enzyme activity when exposed to 4.3 mM ClO2 in the sample after 3 h. Almost all activities were lost in 3 h after exposure to higher ClO2 concentrations of up to 16.8 and 21.9 mM. Changes in protein conformation and amount as a result of ClO2 treatment were determined using the Raman spectroscopy and gel electrophoresis. Raman shifts and the alteration of spectral features observed in the ClO2-treated lysozyme samples are associated with loss of the α-helix secondary structure, tertiary structure, and disulfide bond. Progressive degradation of the denatured lysozyme by increasing levels of chlorine dioxide was also observed in gel electrophoresis. Hence, ClO2 can effectively cause protein denaturation and degradation resulting in loss of enzyme activity.

  17. A conformational switch in the active site of BT_2972, a methyltransferase from an antibiotic resistant pathogen B. thetaiotaomicron.

    Directory of Open Access Journals (Sweden)

    Veerendra Kumar

    Full Text Available Methylation is one of the most common biochemical reactions involved in cellular and metabolic functions and is catalysed by the action of methyltransferases. Bacteroides thetaiotaomicron is an antibiotic-resistant bacterium that confers resistance through methylation, and as yet, there is no report on the structure of methyltransferases from this bacterium. Here, we report the crystal structure of an AdoMet-dependent methyltransferase, BT_2972 and its complex with AdoMet and AdoHcy for B. thetaiotaomicron VPI-5482 strain along with isothermal titration calorimetric assessment of the binding affinities. Comparison of the apo and complexed BT_2972 structures reveals a significant conformational change between open and closed forms of the active site that presumably regulates the association with cofactors and may aid interaction with substrate. Together, our analysis suggests that BT_2972 is a small molecule methyltransferase and might catalyze two O-methylation reaction steps involved in the ubiquinone biosynthesis pathway.

  18. ATP and MO25alpha regulate the conformational state of the STRADalpha pseudokinase and activation of the LKB1 tumour suppressor.

    Science.gov (United States)

    Zeqiraj, Elton; Filippi, Beatrice Maria; Goldie, Simon; Navratilova, Iva; Boudeau, Jérôme; Deak, Maria; Alessi, Dario R; van Aalten, Daan M F

    2009-06-09

    Pseudokinases lack essential residues for kinase activity, yet are emerging as important regulators of signal transduction networks. The pseudokinase STRAD activates the LKB1 tumour suppressor by forming a heterotrimeric complex with LKB1 and the scaffolding protein MO25. Here, we describe the structure of STRADalpha in complex with MO25alpha. The structure reveals an intricate web of interactions between STRADalpha and MO25alpha involving the alphaC-helix of STRADalpha, reminiscent of the mechanism by which CDK2 interacts with cyclin A. Surprisingly, STRADalpha binds ATP and displays a closed conformation and an ordered activation loop, typical of active protein kinases. Inactivity is accounted for by nonconservative substitution of almost all essential catalytic residues. We demonstrate that binding of ATP enhances the affinity of STRADalpha for MO25alpha, and conversely, binding of MO25alpha promotes interaction of STRADalpha with ATP. Mutagenesis studies reveal that association of STRADalpha with either ATP or MO25alpha is essential for LKB1 activation. We conclude that ATP and MO25alpha cooperate to maintain STRADalpha in an "active" closed conformation required for LKB1 activation. It has recently been demonstrated that a mutation in human STRADalpha that truncates a C-terminal region of the pseudokinase domain leads to the polyhydramnios, megalencephaly, symptomatic epilepsy (PMSE) syndrome. We demonstrate this mutation destabilizes STRADalpha and prevents association with LKB1. In summary, our findings describe one of the first structures of a genuinely inactive pseudokinase. The ability of STRADalpha to activate LKB1 is dependent on a closed "active" conformation, aided by ATP and MO25alpha binding. Thus, the function of STRADalpha is mediated through an active kinase conformation rather than kinase activity. It is possible that other pseudokinases exert their function through nucleotide binding and active conformations.

  19. ATP and MO25alpha regulate the conformational state of the STRADalpha pseudokinase and activation of the LKB1 tumour suppressor.

    Directory of Open Access Journals (Sweden)

    Elton Zeqiraj

    2009-06-01

    Full Text Available Pseudokinases lack essential residues for kinase activity, yet are emerging as important regulators of signal transduction networks. The pseudokinase STRAD activates the LKB1 tumour suppressor by forming a heterotrimeric complex with LKB1 and the scaffolding protein MO25. Here, we describe the structure of STRADalpha in complex with MO25alpha. The structure reveals an intricate web of interactions between STRADalpha and MO25alpha involving the alphaC-helix of STRADalpha, reminiscent of the mechanism by which CDK2 interacts with cyclin A. Surprisingly, STRADalpha binds ATP and displays a closed conformation and an ordered activation loop, typical of active protein kinases. Inactivity is accounted for by nonconservative substitution of almost all essential catalytic residues. We demonstrate that binding of ATP enhances the affinity of STRADalpha for MO25alpha, and conversely, binding of MO25alpha promotes interaction of STRADalpha with ATP. Mutagenesis studies reveal that association of STRADalpha with either ATP or MO25alpha is essential for LKB1 activation. We conclude that ATP and MO25alpha cooperate to maintain STRADalpha in an "active" closed conformation required for LKB1 activation. It has recently been demonstrated that a mutation in human STRADalpha that truncates a C-terminal region of the pseudokinase domain leads to the polyhydramnios, megalencephaly, symptomatic epilepsy (PMSE syndrome. We demonstrate this mutation destabilizes STRADalpha and prevents association with LKB1. In summary, our findings describe one of the first structures of a genuinely inactive pseudokinase. The ability of STRADalpha to activate LKB1 is dependent on a closed "active" conformation, aided by ATP and MO25alpha binding. Thus, the function of STRADalpha is mediated through an active kinase conformation rather than kinase activity. It is possible that other pseudokinases exert their function through nucleotide binding and active conformations.

  20. A Rapidly Evolving Active Region NOAA 8032 observed on April ...

    Indian Academy of Sciences (India)

    tribpo

    1997-04-15

    Apr 15, 1997 ... The GOES X-ray data showed a number of sub-flares and two C-class flares during the 8-9 hours of its evolution. ... (1991), where they observed X-class flares near the sites of. EFR. Wang & Shi (1993) suggested that ... region using the USΟ video magnetograph (Mathew et al. 1998). The active region. 233 ...

  1. When Two Heads Aren't Better than One: Conformity in a Group Activity

    Science.gov (United States)

    Fender, C. Melissa; Stickney, Lisa T.

    2017-01-01

    Group and team class decision-making activities often focus on demonstrating that "two heads are better than one." Typically, students solve a problem or complete an assessment individually, then in a group. Generally, the group does better and that is what the students learn. However, if that is all such an activity conveys, then a…

  2. Multiple Conformations of Gal3 Protein Drive the Galactose-Induced Allosteric Activation of the GAL Genetic Switch of Saccharomyces cerevisiae.

    Science.gov (United States)

    Kar, Rajesh Kumar; Kharerin, Hungyo; Padinhateeri, Ranjith; Bhat, Paike Jayadeva

    2017-01-06

    Gal3p is an allosteric monomeric protein that activates the GAL genetic switch of Saccharomyces cerevisiae in response to galactose. Expression of constitutive mutant of Gal3p or overexpression of wild-type Gal3p activates the GAL switch in the absence of galactose. These data suggest that Gal3p exists as an ensemble of active and inactive conformations. Structural data have indicated that Gal3p exists in open (inactive) and closed (active) conformations. However, a mutant of Gal3p that predominantly exists in inactive conformation and is yet capable of responding to galactose has not been isolated. To understand the mechanism of allosteric transition, we have isolated a triple mutant of Gal3p with V273I, T404A, and N450D substitutions, which, upon overexpression, fails to activate the GAL switch on its own but activates the switch in response to galactose. Overexpression of Gal3p mutants with single or double mutations in any of the three combinations failed to exhibit the behavior of the triple mutant. Molecular dynamics analysis of the wild-type and the triple mutant along with two previously reported constitutive mutants suggests that the wild-type Gal3p may also exist in super-open conformation. Furthermore, our results suggest that the dynamics of residue F237 situated in the hydrophobic pocket located in the hinge region drives the transition between different conformations. Based on this study, we suggest that conformational selection mechanism is the driving force in the allosteric transition of Gal3p, which may have implications in other signaling pathways involving monomeric proteins. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Easy and Rapid Purification of Highly Active Nisin

    Directory of Open Access Journals (Sweden)

    André Abts

    2011-01-01

    Full Text Available Nisin is an antimicrobial peptide produced and secreted by several L. lactis strains and is specifically active against Gram-positive bacteria. In previous studies, nisin was purified via cation exchange chromatography at low pH employing a single-step elution using 1 M NaCl. Here, we describe an optimized purification protocol using a five-step NaCl elution to remove contaminants. The obtained nisin is devoid of impurities and shows high bactericidal activity against the nisin-sensitive L. lactis strain NZ9000. Purified nisin exhibits an IC50 of ~3 nM, which is a tenfold improvement as compared to nisin obtained via the one-step elution procedure.

  4. Targeting the autolysis loop of urokinase-type plasminogen activator with conformation-specific monoclonal antibodies

    DEFF Research Database (Denmark)

    Bøtkjær, Kenneth Alrø; Fogh, Sarah; Bekes, Erin C

    2011-01-01

    Tight regulation of serine proteases is essential for their physiological function, and unbalanced states of protease activity have been implicated in a variety of human diseases. One key example is the presence of uPA (urokinase-type plasminogen activator) in different human cancer types......, with high levels correlating with a poor prognosis. This observation has stimulated efforts into finding new principles for intervening with uPA's activity. In the present study we characterize the so-called autolysis loop in the catalytic domain of uPA as a potential inhibitory target. This loop was found...

  5. A rapid assay for the biological evaluation of helicase activity.

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Dimitrios Vlachakis, Andrea Brancale, Colin Berry & Sophia Kossida ### Abstract A new assay for the measurement of helicase enzyme activity was developed for the evaluation of the potency of potential inhibitors. This assay involves the use of a DNA or RNA duplex substrate and recombinant purified helicase. The DNA duplex consists of a pair of oligonucleotides, one of which is biotinylated and the other is digoxygenin (DIG)-labelled, both at their respective 5’ termini. This ...

  6. Kepler Observations of Rapid Optical Variability in Active Galactic Nuclei

    Science.gov (United States)

    Mushotzky, R. F.; Edelson, R.; Baumgartner, W. H.; Gandhi, P.

    2012-01-01

    Over three quarters in 2010 - 2011, Kepler monitored optical emission from four active galactic nuclei (AGN) with approx 30 min sampling, > 90% duty cycle and approx law slopes of -2.6 to -3.3, much steeper than typically seen in the X-rays. We find evidence that individual AGN exhibit intrinsically different PSD slopes. The steep PSD fits are a challenge to recent AGN variability models but seem consistent with first order MRI theoretical calculations of accretion disk fluctuations.

  7. Template Based Design of Anti-Metastatic Drugs from the Active Conformation of Laminin Peptide II

    Science.gov (United States)

    2001-01-01

    bioactivities of 0 A BA B C D E peptide 11, a non- oxidizable monomer of peptide 11 containing an Acm protected cysteine residue and peptide 11 dimer. The...anti-metastatic activity of peptide 11, a non oxidizable Acm protected analog of peptide 11 and peptide 11 dimer. The most active species was the...importance of the QPATEDWSA sequence heparan sulfate eluate. However, a heparan sulfate to bioactivity of the peptide. DG44CHO cells attach labile

  8. ATP and MO25α Regulate the Conformational State of the STRADα Pseudokinase and Activation of the LKB1 Tumour Suppressor

    Science.gov (United States)

    Zeqiraj, Elton; Filippi, Beatrice Maria; Goldie, Simon; Navratilova, Iva; Boudeau, Jérôme; Deak, Maria; Alessi, Dario R.; van Aalten, Daan M. F.

    2009-01-01

    Pseudokinases lack essential residues for kinase activity, yet are emerging as important regulators of signal transduction networks. The pseudokinase STRAD activates the LKB1 tumour suppressor by forming a heterotrimeric complex with LKB1 and the scaffolding protein MO25. Here, we describe the structure of STRADα in complex with MO25α. The structure reveals an intricate web of interactions between STRADα and MO25α involving the αC-helix of STRADα, reminiscent of the mechanism by which CDK2 interacts with cyclin A. Surprisingly, STRADα binds ATP and displays a closed conformation and an ordered activation loop, typical of active protein kinases. Inactivity is accounted for by nonconservative substitution of almost all essential catalytic residues. We demonstrate that binding of ATP enhances the affinity of STRADα for MO25α, and conversely, binding of MO25α promotes interaction of STRADα with ATP. Mutagenesis studies reveal that association of STRADα with either ATP or MO25α is essential for LKB1 activation. We conclude that ATP and MO25α cooperate to maintain STRADα in an “active” closed conformation required for LKB1 activation. It has recently been demonstrated that a mutation in human STRADα that truncates a C-terminal region of the pseudokinase domain leads to the polyhydramnios, megalencephaly, symptomatic epilepsy (PMSE) syndrome. We demonstrate this mutation destabilizes STRADα and prevents association with LKB1. In summary, our findings describe one of the first structures of a genuinely inactive pseudokinase. The ability of STRADα to activate LKB1 is dependent on a closed “active” conformation, aided by ATP and MO25α binding. Thus, the function of STRADα is mediated through an active kinase conformation rather than kinase activity. It is possible that other pseudokinases exert their function through nucleotide binding and active conformations. PMID:19513107

  9. Trypsinogen-trypsin transition: a molecular dynamics study of induced conformational change in the activation domain.

    Science.gov (United States)

    Brünger, A T; Huber, R; Karplus, M

    1987-08-11

    The trypsinogen to trypsin transition has been investigated by a stochastic boundary molecular dynamics simulation that included a major portion of the trypsin molecule and the surrounding solvent. Attention focused on the "activation domain", which crystallographic studies have shown to be ordered in trypsin and disordered in its zymogen, trypsinogen. The chain segments that form the activation domain were found to exhibit large fluctuations during the simulation of trypsin. To model a difference between trypsin and trypsinogen, the N-terminal residues Ile-16 and Val-17 were removed in the former and replaced by water molecules. As a result of the perturbation, a structural drift of 1-2 A occurred that is limited to the activation domain. Glycine residues are found to act as hinges for the displaced chain segments.

  10. Conformational changes in a hyperthermostable glycoside hydrolase: enzymatic activity is a consequence of the loop dynamics and protonation balance.

    Directory of Open Access Journals (Sweden)

    Leandro C de Oliveira

    Full Text Available Endo-β-1, 4-mannanase from Thermotoga petrophila (TpMan is a modular hyperthermostable enzyme involved in the degradation of mannan-containing polysaccharides. The degradation of these polysaccharides represents a key step for several industrial applications. Here, as part of a continuing investigation of TpMan, the region corresponding to the GH5 domain (TpManGH5 was characterized as a function of pH and temperature. The results indicated that the enzymatic activity of the TpManGH5 is pH-dependent, with its optimum activity occurring at pH 6. At pH 8, the studies demonstrated that TpManGH5 is a molecule with a nearly spherical tightly packed core displaying negligible flexibility in solution, and with size and shape very similar to crystal structure. However, TpManGH5 experiences an increase in radius of gyration in acidic conditions suggesting expansion of the molecule. Furthermore, at acidic pH values, TpManGH5 showed a less globular shape, probably due to a loop region slightly more expanded and flexible in solution (residues Y88 to A105. In addition, molecular dynamics simulations indicated that conformational changes caused by pH variation did not change the core of the TpManGH5, which means that only the above mentioned loop region presents high degree of fluctuations. The results also suggested that conformational changes of the loop region may facilitate polysaccharide and enzyme interaction. Finally, at pH 6 the results indicated that TpManGH5 is slightly more flexible at 65°C when compared to the same enzyme at 20°C. The biophysical characterization presented here is well correlated with the enzymatic activity and provide new insight into the structural basis for the temperature and pH-dependent activity of the TpManGH5. Also, the data suggest a loop region that provides a starting point for a rational design of biotechnological desired features.

  11. Theoretical studies on beta-lactam antibiotics. I. Conformational similarity of penicillins and cephalosporins to X-D-alanyl-D-alanine and correlation of their structure with activity.

    Science.gov (United States)

    Virudachalam, R; Rao, V S

    1977-01-01

    The substrate analogue hypothesis proposed for the mechanism of the action of penicillins and cephalosporins is examined by stereochemical criteria. These beta-lactam antibiotics assume conformation similar to X-D-alanyl-D-alanine due to the presence of the lactam ring; this disagrees with the assumption made by Tipper & Strominger that L and D amino acid residues take similar conformation. The model proposed in this study for the activity of these antibiotics differs considerably from the earlier models, mainly in phi2 rotational angle which determines the conformation of the aminoacyl group. The inactivity of C6 or C7 epimers and the effect of various substitutions at 6alpha or 7alpha and C2 positions of penicillins and cephalosporins on the biological activity are explained.

  12. Oculocutaneous albinism type 1: link between mutations, tyrosinase conformational stability, and enzymatic activity.

    Science.gov (United States)

    Dolinska, Monika B; Kus, Nicole J; Farney, S Katie; Wingfield, Paul T; Brooks, Brian P; Sergeev, Yuri V

    2017-01-01

    Oculocutaneous albinism type 1 (OCA1) is an autosomal recessive disorder caused by mutations in the tyrosinase gene. Two subtypes of OCA1 have been described: severe OCA1A with complete absence of tyrosinase activity and less severe OCA1B with residual tyrosinase activity. Here, we characterize the recombinant human tyrosinase intramelanosomal domain and mutant variants, which mimic genetic changes in both subtypes of OCA1 patients. Proteins were prepared using site-directed mutagenesis, expressed in insect larvae, purified by chromatography, and characterized by enzymatic activities, tryptophan fluorescence, and Gibbs free energy changes. The OCA1A mutants showed very low protein expression and protein yield and are enzymatically inactive. Mutants mimicking OCA1B were biochemically similar to the wild type, but exhibited lower specific activities and protein stabilities. The results are consistent with clinical data, which indicates that OCA1A mutations inactivate tyrosinase and result in severe phenotype, while OCA1B mutations partially inactivate tyrosinase and result in OCA1B albinism. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  13. Oculocutaneous Albinism Type 1: Link between Mutations, Tyrosinase Conformational Stability, and Enzymatic Activity

    Science.gov (United States)

    Dolinska, Monika B.; Kus, Nicole; Farney, Katie; Wingfield, Paul T.; Brooks, Brian P.; Sergeev, Yuri V.

    2017-01-01

    Summary Oculocutaneous albinism Type 1 (OCA1) is an autosomal recessive disorder caused by mutations in the tyrosinase gene. Two subtypes of OCA1 have been described: severe OCA1A with complete absence of tyrosinase activity and less severe OCA1B with residual tyrosinase activity. Here, we characterize the recombinant human tyrosinase intra-melanosomal domain and mutant variants, which mimic genetic changes in both subtypes of OCA1 patients. Proteins were prepared using site-directed mutagenesis, expressed in insect larvae, purified by chromatography, and characterized by enzymatic activities- tryptophan fluorescence, and Gibbs free energy changes. The OCA1A mutants show very low protein expression, protein yield, and are enzymatically inactive. Mutants mimicking OCA1B were biochemically similar to the wild type, but exhibited lower specific activities and protein stabilities. The results are consistent with clinical data, which indicates that OCA1A mutations inactivate tyrosinase and result in severe phenotype, while OCA1B mutations partially inactive tyrosinase and results in OCA1B albinism. PMID:27775880

  14. The cyclopentyl group, as a small but bulky terminal group, allows rapid and efficient active transport.

    Science.gov (United States)

    Nishiyama, Junya; Makita, Yoshimasa; Kihara, Nobuhiro

    2015-01-02

    Secondary ammonium salts bearing a cyclopentyl terminal group rapidly formed pseudorotaxane with 1.5 equiv of DB24C8. Acylation of the pseudorotaxane with 50 equiv of benzoyl chloride in the presence of 50 equiv of triethylamine in toluene afforded rotaxane, the product of active transport, in 95% yield. The cyclopentyl group is small enough to allow rapid formation of pseudorotaxane, and bulky enough to facilitate the quantitative active transport by steric repulsion.

  15. Conformational plasticity surrounding the active site of NADH oxidase from Thermus thermophilus.

    Science.gov (United States)

    Miletti, Teresa; Di Trani, Justin; Levros, Louis-Charles; Mittermaier, Anthony

    2015-07-01

    Biotechnological applications of enzymes can involve the use of these molecules under nonphysiological conditions. Thus, it is of interest to understand how environmental variables affect protein structure and dynamics and how this ultimately modulates enzyme function. NADH oxidase (NOX) from Thermus thermophilus exemplifies how enzyme activity can be tuned by reaction conditions, such as temperature, cofactor substitution, and the addition of cosolutes. This enzyme catalyzes the oxidation of reduced NAD(P)H to NAD(P)(+) with the concurrent reduction of O2 to H2O2, with relevance to biosensing applications. It is thermophilic, with an optimum temperature of approximately 65°C and sevenfold lower activity at 25°C. Moderate concentrations (≈1M) of urea and other chaotropes increase NOX activity by up to a factor of 2.5 at room temperature. Furthermore, it is a flavoprotein that accepts either FMN or the much larger FAD as cofactor. We have used nuclear magnetic resonance (NMR) titration and (15)N spin relaxation experiments together with isothermal titration calorimetry to study how NOX structure and dynamics are affected by changes in temperature, the addition of urea and the substitution of the FMN cofactor with FAD. The majority of signals from NOX are quite insensitive to changes in temperature, cosolute addition, and cofactor substitution. However, a small cluster of residues surrounding the active site shows significant changes. These residues are implicated in coupling changes in the solution conditions of the enzyme to changes in catalytic activity. © 2015 The Protein Society.

  16. An in silico study of the molecular basis of B-RAF activation and conformational stability

    DEFF Research Database (Denmark)

    Fratev, Filip Filipov; Jonsdottir, Svava Osk

    2009-01-01

    based on molecular dynamics (MD) simulations of B-RAFWT and the B-RAFV600E, B-RAFK601E and B-RAFD594V mutants. A strong hydrogen bond network was identified in B-RAFWT in which the interactions between Lys601 and the well known catalytic residues Lys483, Glu501 and Asp594 play an important role......B-RAF kinase plays an important role both in tumour induction and maintenance in several cancers and it is an attractive new drug target. However, the structural basis of the B-RAF activation is still not well understood. RESULTS: In this study we suggest a novel molecular basis of B-RAF activation...

  17. Tracking voltage-dependent conformational changes in skeletal muscle sodium channel during activation.

    Science.gov (United States)

    Chanda, Baron; Bezanilla, Francisco

    2002-11-01

    The primary voltage sensor of the sodium channel is comprised of four positively charged S4 segments that mainly differ in the number of charged residues and are expected to contribute differentially to the gating process. To understand their kinetic and steady-state behavior, the fluorescence signals from the sites proximal to each of the four S4 segments of a rat skeletal muscle sodium channel were monitored simultaneously with either gating or ionic currents. At least one of the kinetic components of fluorescence from every S4 segment correlates with movement of gating charge. The fast kinetic component of fluorescence from sites S216C (S4 domain I), S660C (S4 domain II), and L1115C (S4 domain III) is comparable to the fast component of gating currents. In contrast, the fast component of fluorescence from the site S1436C (S4 domain IV) correlates with the slow component of gating. In all the cases, the slow component of fluorescence does not have any apparent correlation with charge movement. The fluorescence signals from sites reflecting the movement of S4s in the first three domains initiate simultaneously, whereas the fluorescence signals from the site S1436C exhibit a lag phase. These results suggest that the voltage-dependent movement of S4 domain IV is a later step in the activation sequence. Analysis of equilibrium and kinetic properties of fluorescence over activation voltage range indicate that S4 domain III is likely to move at most hyperpolarized potentials, whereas the S4s in domain I and domain II move at more depolarized potentials. The kinetics of fluorescence changes from sites near S4-DIV are slower than the activation time constants, suggesting that the voltage-dependent movement of S4-DIV may not be a prerequisite for channel opening. These experiments allow us to map structural features onto the kinetic landscape of a sodium channel during activation.

  18. Carbon Nanotube Active-Matrix Backplanes for Conformal Electronics and Sensors

    Science.gov (United States)

    2011-11-03

    REPORT TYPE New Reprint 17. LIMITATION OF ABSTRACT UU 15. NUMBER OF PAGES 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 5c. PROGRAM...beenintensively explored for enabling new applications otherwise unachievable with the conventional Si technology.13 A wide range of active channel...McEuen, P. L.; Fuhrer , M.; Park, H. IEEE Trans. Nanotechnol. 2002, 1, 78. (23) Javey, A. ACS Nano 2008, 2, 1329–1335. (24) Patil, N.; Lin, A.; Myers

  19. Relief of autoinhibition by conformational switch explains enzyme activation by a catalytically dead paralog

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, Oleg A.; Kinch, Lisa; Ariagno, Carson; Deng, Xiaoyi; Zhong, Shihua; Grishin, Nick; Tomchick, Diana R.; Chen, Zhe; Phillips, Margaret A.

    2016-12-15

    Catalytically inactive enzyme paralogs occur in many genomes. Some regulate their active counterparts but the structural principles of this regulation remain largely unknown. We report X-ray structures ofTrypanosoma brucei S-adenosylmethionine decarboxylase alone and in functional complex with its catalytically dead paralogous partner, prozyme. We show monomericTbAdoMetDC is inactive because of autoinhibition by its N-terminal sequence. Heterodimerization with prozyme displaces this sequence from the active site through a complex mechanism involving acis-to-transproline isomerization, reorganization of a β-sheet, and insertion of the N-terminal α-helix into the heterodimer interface, leading to enzyme activation. We propose that the evolution of this intricate regulatory mechanism was facilitated by the acquisition of the dimerization domain, a single step that can in principle account for the divergence of regulatory schemes in the AdoMetDC enzyme family. These studies elucidate an allosteric mechanism in an enzyme and a plausible scheme by which such complex cooperativity evolved.

  20. Myelin 2',3'-cyclic nucleotide 3'-phosphodiesterase: active-site ligand binding and molecular conformation.

    Directory of Open Access Journals (Sweden)

    Matti Myllykoski

    Full Text Available The 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase is a highly abundant membrane-associated enzyme in the myelin sheath of the vertebrate nervous system. CNPase is a member of the 2H phosphoesterase family and catalyzes the formation of 2'-nucleotide products from 2',3'-cyclic substrates; however, its physiological substrate and function remain unknown. It is likely that CNPase participates in RNA metabolism in the myelinating cell. We solved crystal structures of the phosphodiesterase domain of mouse CNPase, showing the binding mode of nucleotide ligands in the active site. The binding mode of the product 2'-AMP provides a detailed view of the reaction mechanism. Comparisons of CNPase crystal structures highlight flexible loops, which could play roles in substrate recognition; large differences in the active-site vicinity are observed when comparing more distant members of the 2H family. We also studied the full-length CNPase, showing its N-terminal domain is involved in RNA binding and dimerization. Our results provide a detailed picture of the CNPase active site during its catalytic cycle, and suggest a specific function for the previously uncharacterized N-terminal domain.

  1. Enhanced osteogenic activity of anatase TiO2 film: Surface hydroxyl groups induce conformational changes in fibronectin.

    Science.gov (United States)

    Lv, Lin; Li, Kai; Xie, Youtao; Cao, Yunzhen; Zheng, Xuebin

    2017-09-01

    In this study, with an attempt to identify the effects of TiO2 crystalline phase compositions on the osteogenic properties, the anatase and rutile TiO2 thin films with similar film thickness, surface topography and hydrophilicity were prepared on Si (100) substrates by atomic layer deposition (ALD), subsequent thermal annealing and ultraviolet irradiation. The films were studied with XRD, XPS, FE-SEM, AFM, FTIR and contact angle measurements. In vitro cellular assays showed that the anatase phase led to better osteoblast compatibility in terms of adhesion, proliferation, differentiation, mineralization as well as osteogenesis-related gene expression when compared with the rutile phase. We investigated the difference between the anatase and rutile TiO2 films at the biomolecular level to explain the enhanced osteogenic activity of the anatase film. It was found that the presence of more TiOH groups on anatase surface induced more cell-binding sites of fibronectin (FN) exposed on its surface, causing a more active conformation of the adsorbed FN for subsequent osteoblast behaviors. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Synthesis, structure combined with conformational analysis, biological activities and docking studies of bis benzylidene cyclohexanone derivatives

    Directory of Open Access Journals (Sweden)

    Gehad Lotfy

    2017-07-01

    Full Text Available We report the synthesis and biological evaluation of bis benzylidne cyclohexanone derivatives 2,6-di(4-fluorobenzylidenecyclohexanone 3a and (2E,6E‐2,6‐bis({[4‐(trifluoromethylphenyl]methylidene}cyclohexanone 3b. Compound 3b crystallized in the monoclinic space group P21/n with unit cell parameters a = 29.3527(12 Å, b = 8.3147(3 Å, c = 32.7452(14 Å, β = 112.437(2°, and V = 7386.8(5 Å3, Z = 16, and Rint = 0.072 at T = 100 K. The asymmetric unit contains four independent molecules, each of which has slight differences in the bond lengths and angles. One non-classical C11D–H11F⋯F3A hydrogen bond connects the molecules. Density functional theory was used to optimize the structures and calculate the natural charges, dipole moments, frontier molecular orbitals, and NMR and UV–Vis spectroscopic properties, which are discussed and compared with the experimental data. The synthetic derivatives were evaluated for α-glucosidase inhibitory activity, and we found that compound 3a (IC50 = 96.3 ± 0.51 μM is a potent α-glucosidase inhibitor, showing superior activity to the standard drug acarbose (IC50 = 841 ± 1.73 μM. Compound 3b (IC50 = 7.92 ± 1.3 μg/mL was found to be a potent antileishmanial compound, especially compared to the antileishmanial drugs pentamidine (IC50 = 5.09 ± 0.04 μM and amphotericine B (IC50 = 0.29 ± 0.05 μg/mL. In addition, 3a and 3b have cytotoxic effects against PC3 (prostate cancer, HeLa (cervical cancer, and MCF-3 (breast cancer cell lines. Docking study for compounds activity was performed with Openeye software in order to understanding their pose of interaction in the target receptors.

  3. Ataxia Telangiectasia-Mutated (ATM) kinase activity is regulated by ATP-driven conformational changes in the Mre11/Rad50/Nbs1 (MRN) complex

    NARCIS (Netherlands)

    J.-H. Lee (Ji-Hoon); M.R. Mand (Michael); R.A. Deshpande (Rajashree); E. Kinoshita (Eri); S.-H. Yang (Soo-Hyun); C. Wyman (Claire); T.T. Paull

    2013-01-01

    textabstractThe Ataxia Telangiectasia-Mutated (ATM) protein kinase is recruited to sites of double-strand DNA breaks by the Mre11/Rad50/Nbs1 (MRN) complex, which also facilitates ATM monomerization and activation. MRN exists in at least two distinct conformational states, dependent on ATP binding

  4. Thermal effects on the activity and structural conformation of catechol 2,3-dioxygenase from Pseudomonas putida SH1.

    Science.gov (United States)

    Huang, Shir-Ly; Hsu, Yuan-Chang; Wu, Chun-Ming; Lynn, Jeffrey W; Li, Wen-Hsien

    2010-01-21

    A bacterium, Pseudomonas putida SH1, which can catabolize phenol, naphthalene, or cresol as the sole carbon and energy source, was isolated from a petroleum-contaminated site in Taiwan. The catechol 2,3-dioxygenase (C23O) was purified from this bacterial strain when grown on naphthalene as the sole carbon and energy source. The enzyme is composed of four identical subunits with a native molecular weight of 128 +/- 5 kD. Small-angle neutron scattering (SANS) techniques were employed to study the thermal effects on the structural conformation of this enzyme in solution. The SANS measurements revealed distinct changes in the size of the enzyme between 50 and 80 degrees C, and the size was not restored during the subsequent cooling. The enzyme started to denature at 55 degrees C, and the structure was destroyed by the time the temperature reached 80 degrees C, at which the enzyme had become more than twice the original size. The optimal catalytic temperature of the enzyme was at 50 degrees C. The half-life of the activity at this temperature was 45 min. The enzyme activity increases starting from 25 degrees C and reaches its maximum at 50 degrees C, below which no obvious change in the size of the enzyme is found. Noticeable enlargement of the enzyme is revealed when the enzymatic activity starts to fall. By combination of SANS measurement and biochemical properties of the enzyme, this study demonstrates the correlation of enzyme size in solution and catalytic activity upon a heat treatment. In addition, for a protein composed of multiple subunits, the shape of the enzyme and the dissociation of the enzyme subunits in a thermal cycle were also demonstrated by SANS methodology.

  5. 20 CFR 665.300 - What are rapid response activities and who is responsible for providing them?

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What are rapid response activities and who is responsible for providing them? 665.300 Section 665.300 Employees' Benefits EMPLOYMENT AND TRAINING... INVESTMENT ACT Rapid Response Activities § 665.300 What are rapid response activities and who is responsible...

  6. Conformational changes in human Hsp70 induced by high hydrostatic pressure produce oligomers with ATPase activity but without chaperone activity.

    Science.gov (United States)

    Araujo, Thaís L S; Borges, Julio Cesar; Ramos, Carlos H; Meyer-Fernandes, José Roberto; Oliveira Júnior, Reinaldo S; Pascutti, Pedro G; Foguel, Debora; Palhano, Fernando L

    2014-05-13

    We investigated the folding of the 70 kDa human cytosolic inducible protein (Hsp70) in vitro using high hydrostatic pressure as a denaturing agent. We followed the structural changes in Hsp70 induced by high hydrostatic pressure using tryptophan fluorescence, molecular dynamics, circular dichroism, high-performance liquid chromatography gel filtration, dynamic light scattering, ATPase activity, and chaperone activity. Although monomeric, Hsp70 is very sensitive to hydrostatic pressure; after pressure had been removed, the protein did not return to its native sate but instead formed oligomeric species that lost chaperone activity but retained ATPase activity.

  7. Effects of heat treatment on conformation and cell growth activity of alpha- lactalbumin and beta-lactoglobulin from market milk.

    Science.gov (United States)

    Inagaki, Mizuho; Kawai, Shuji; Ijier, X; Fukuoka, Mayuko; Yabe, Tomio; Iwamoto, Satoshi; Kanamaru, Yoshihiro

    2017-01-01

    Heat processes, low temperature for long time (LTLT) pasteurization and ultra-heat treatment (UHT) sterilization, are essential for commercial market milk to improve the shelf life of raw milk and ensure microbial safety. We evaluated the effects of heat experience on the molecular properties of α-lactalbumin (α-LA) and β-lactoglobulin (β-LG) isolated from four types of market milk such as LTLT-A (66°C for 30 min), LTLT-B (65°C for 30 min), UHT-I (130°C for 2 s, indirect heating) and UHT-D (135°C for 2 s, direct heating) samples. We examined molecular conformations using circular dichroism spectrum measurement and cell growth activity using the WST-1 method for the proteins. α-LA isolated from each of these four types of market milk displayed no significant structural difference as compared to raw milk α-LA, while α-LA of UHT-I only inhibited cell growth of an intestinal epithelial cell line more potently than raw milk α-LA. In the case of β-LG, only the UHT-I sample demonstrated a drastic change in structure, while it did not exhibit any cytotoxicity. We found that cell viability effects of α-LA and β-LG are attributable to the type of UHT; indirect and direct. These findings indicate that the effect of heat treatment on whey proteins should carefully be investigated further.

  8. Structural ordering of disordered ligand-binding loops of biotin protein ligase into active conformations as a consequence of dehydration.

    Directory of Open Access Journals (Sweden)

    Vibha Gupta

    Full Text Available Mycobacterium tuberculosis (Mtb, a dreaded pathogen, has a unique cell envelope composed of high fatty acid content that plays a crucial role in its pathogenesis. Acetyl Coenzyme A Carboxylase (ACC, an important enzyme that catalyzes the first reaction of fatty acid biosynthesis, is biotinylated by biotin acetyl-CoA carboxylase ligase (BirA. The ligand-binding loops in all known apo BirAs to date are disordered and attain an ordered structure only after undergoing a conformational change upon ligand-binding. Here, we report that dehydration of Mtb-BirA crystals traps both the apo and active conformations in its asymmetric unit, and for the first time provides structural evidence of such transformation. Recombinant Mtb-BirA was crystallized at room temperature, and diffraction data was collected at 295 K as well as at 120 K. Transfer of crystals to paraffin and paratone-N oil (cryoprotectants prior to flash-freezing induced lattice shrinkage and enhancement in the resolution of the X-ray diffraction data. Intriguingly, the crystal lattice rearrangement due to shrinkage in the dehydrated Mtb-BirA crystals ensued structural order of otherwise flexible ligand-binding loops L4 and L8 in apo BirA. In addition, crystal dehydration resulted in a shift of approximately 3.5 A in the flexible loop L6, a proline-rich loop unique to Mtb complex as well as around the L11 region. The shift in loop L11 in the C-terminal domain on dehydration emulates the action responsible for the complex formation with its protein ligand biotin carboxyl carrier protein (BCCP domain of ACCA3. This is contrary to the involvement of loop L14 observed in Pyrococcus horikoshii BirA-BCCP complex. Another interesting feature that emerges from this dehydrated structure is that the two subunits A and B, though related by a noncrystallographic twofold symmetry, assemble into an asymmetric dimer representing the ligand-bound and ligand-free states of the protein, respectively. In

  9. Rapid Detection of Glycogen Synthase Kinase-3 Activity in Mouse Sperm Using Fluorescent Gel Shift Electrophoresis

    National Research Council Canada - National Science Library

    Choi, Hoseok; Choi, Bomi; Seo, Ju Tae; Lee, Kyung Jin; Gye, Myung Chan; Kim, Young-Pil

    2016-01-01

    .... The GSK3 activity in mouse testes and sperm were quantifiable by gel shift assay with low sample consumption and were significantly correlated with the expression levels of GSK3 and p-GSK3. We suggest that our assay can be used for reliable and rapid detection of GSK3 activity in cells and tissue extracts.

  10. Rapid Shifts in Soil Nutrients and Decomposition Enzyme Activity in Early Succession Following Forest Fire

    OpenAIRE

    Knelman, Joseph E.; Graham, Emily B; Scott Ferrenberg; Aurélien Lecoeuvre; Amanda Labrado; Darcy, John L.; Nemergut, Diana R; Schmidt, Steven K.

    2017-01-01

    While past research has studied forest succession on decadal timescales, ecosystem responses to rapid shifts in nutrient dynamics within the first months to years of succession after fire (e.g., carbon (C) burn-off, a pulse in inorganic nitrogen (N), accumulation of organic matter, etc.) have been less well documented. This work reveals how rapid shifts in nutrient availability associated with fire disturbance may drive changes in soil enzyme activity on short timescales in forest secondary s...

  11. Evaluation of antimicrobial activity of selected plant extracts by rapid XTT colorimetry and bacterial enumeration.

    Science.gov (United States)

    Al-Bakri, Amal G; Afifi, Fatma U

    2007-01-01

    The aim of this study was to screen and evaluate the antimicrobial activity of indigenous Jordanian plant extracts, dissolved in dimethylsulfoxide, using the rapid XTT assay and viable count methods. XTT rapid assay was used for the initial screening of antimicrobial activity for the plant extracts. Antimicrobial activity of potentially active plant extracts was further assessed using the "viable plate count" method. Four degrees of antimicrobial activity (high, moderate, weak and inactive) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, were recorded. The plant extracts of Hypericum triquetrifolium, Ballota undulata, Ruta chalepensis, Ononis natrix, Paronychia argentea and Marrubium vulgare had shown promising antimicrobial activity. This study showed that while both XTT and viable count methods are comparable when estimating the overall antimicrobial activity of experimental substances, there is no strong linear correlation between the two methods.

  12. Intramolecular disulfide bonds are required for folding hydrolase B into a catalytically active conformation but not for maintaining it during catalysis.

    Science.gov (United States)

    Song, Xiulong; Gragen, Sarah; Li, Yuxin; Ma, Yuzhong; Liu, Jirong; Yang, Dongfang; Matoney, Lynn; Yan, Bingfang

    2004-07-09

    Carboxylesterases represent a large class of hydrolytic enzymes that are involved in lipid metabolism, pharmacological determination, and detoxication of organophosphorus pesticides. These enzymes have several notable structural features including two intramolecular disulfide bonds. This study was undertaken to test the hypothesis that the disulfide bonds are required during catalysis by stabilizing the catalytically active conformation. Hydrolase B, a rat liver microsomal carboxylesterase, was reduced by dithiothreitol, electrophoretically separated and assayed for hydrolysis. Contrary to the hypothesis, reduced hydrolase B was as active as the native enzyme on the hydrolysis of 1-naphthylacetate, and sulfhydryl alkylation following reduction caused no changes in the hydrolytic activity. Interestingly, substitution of a disulfide bond-forming cysteine with an alanine caused marked reduction or complete loss of the catalytic activity, suggesting that disulfide bond formation plays a role in the biosynthetic process of hydrolase B. In support of this notion, refolding experiments restored a significant amount of hydrolytic activity when hydrolase B was unfolded with urea alone. In contrast, little activity was restored when unfolding was performed in the presence of reducing agent dithiothreitol. These results suggest that formation of the disulfide bonds plays a critical role in folding hydrolase B into the catalytically active conformation, and that the disulfide bonds play little role or function redundantly in maintaining this conformation during catalysis.

  13. Esterification activity and conformation studies of Burkholderia cepacia lipase in conventional organic solvents, ionic liquids and their co-solvent mixture media.

    Science.gov (United States)

    Pan, Shaotao; Liu, Xue; Xie, Yadong; Yi, Yuyin; Li, Chong; Yan, Yunjun; Liu, Yun

    2010-12-01

    In this work, experiments were carried out to evaluate the esterification activity and conformation of lipase from Burkholderia cepacia in the selected conventional organic solvents, ionic liquids and their co-solvent mixture media. The results revealed that the activity of esterification of B. cepacia lipase was mostly highest in co-solvent mixture of ionic liquids-organic solvents, followed by conventional organic solvents and ionic liquids. Hence, co-solvent mixture was a high-effective strategy to enhance the activity of B. cepacia lipase for non-aqueous enzymology reaction. Conformational studies via circular dichroism spectroscopy indicated that the secondary structure of B. cepacia lipase was variant in the above-mentioned media, especially the content of alpha-helix, which was probably responsible for lipase activity difference. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  14. Rapid Detection of Glycogen Synthase Kinase-3 Activity in Mouse Sperm Using Fluorescent Gel Shift Electrophoresis

    OpenAIRE

    Hoseok Choi; Bomi Choi; Ju Tae Seo; Kyung Jin Lee; Myung Chan Gye; Young-Pil Kim

    2016-01-01

    Assaying the glycogen synthase kinase-3 (GSK3) activity in sperm is of great importance because it is closely implicated in sperm motility and male infertility. While a number of studies on GSK3 activity have relied on labor-intensive immunoblotting to identify phosphorylated GSK3, here we report the simple and rapid detection of GSK3 activity in mouse sperm using conventional agarose gel electrophoresis and a fluorescent peptide substrate. When a dye-tethered and prephosphorylated (primed) p...

  15. Music training enhances rapid plasticity of N1 and P2 source activation for unattended sounds

    Directory of Open Access Journals (Sweden)

    Miia eSeppänen

    2012-03-01

    Full Text Available Neurocognitive studies demonstrate that long-term musical training enhances the processing of unattended sounds. It is not clear, however, whether musical training modulates also rapid (within tens of minutes neural plasticity for sound encoding. To study this, we examined whether adult musicians display enhanced rapid neural plasticity when compared to nonmusicians. More specifically, we examined the modulation of P1, N1, and P2 responses to regular standard sounds in an oddball paradigm between unattended passive blocks which were separated by an active task. Source analysis for event-related potentials showed that N1 and P2 source activation decreased selectively in musicians already after fifteen minutes of passive exposure to sounds and that P2 source activation re-enhanced after the active task in musicians. Additionally, event-related potential (ERP analysis revealed that in both musicians and nonmusicians, P2 ERP amplitude enhanced after fifteen minutes of passive exposure but only at frontal electrodes. Furthermore, in musicians, N1 ERP enhanced after the active discrimination task but only at parietal electrodes. Musical training modulates the rapid plasticity reflected in N1 and P2 source activation for unattended regular standard sounds. Enhanced rapid plasticity of N1 and P2 might reflect the faster auditory perceptual learning in musicians when compared to nonmusicians.

  16. The Achilles' Heel of "Ultrastable" Hyperthermophile Proteins: Submillimolar Concentrations of SDS Stimulate Rapid Conformational Change, Aggregation, and Amyloid Formation in Proteins Carrying Overall Positive Charge.

    Science.gov (United States)

    Khan, Javed M; Sharma, Prerna; Arora, Kanika; Kishor, Nitin; Kaila, Pallavi; Guptasarma, Purnananda

    2016-07-19

    Low concentrations (SDS) have been shown to induce the formation of amyloid fibers in more than 20 different mesophile-derived proteins in the cationic state. It is not known whether SDS has similar effects on hyperthermophile-derived proteins, which are otherwise thought to be "ultrastable" and inordinately resistant to structural perturbations at room temperature. Here, we show that low (SDS rapidly induce the formation of aggregates and amyloid fibers in five different ultrastable Pyrococcus furiosus proteins in the cationic state. We also show that amyloid formation is accompanied by the development of a characteristic, negative circular dichroism band at ∼230 nm. These effects are not seen if the proteins have a net negative charge or when higher concentrations of SDS are used (which induce helix formation instead). Our results appear to reveal a potential weakness or "Achilles' heel" in ultrastable proteins from hyperthermophiles. They also provide very strong support for the view that SDS initially interacts with proteins through electrostatic interactions, and not hydrophobic interactions, eliciting similar effects entirely regardless of protein molecular weight, or structural features such as quaternary structure or tertiary structural stability.

  17. Synthesis, conformational analysis, and biological activities of cyclic enkephalins and model cyclic peptides containing thioamides as amide bond replacements

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, D.B.

    1988-01-01

    This thesis describes the first applications of the thioamide surrogate ({psi}(CSNH)) in model cyclic peptides and cyclic enkephalins. The solution phase synthesis and conformational analysis of two model cyclic endothiopentapeptides, cyclo(D-Phe-Pro{psi} (CSNH)Gly-Pro-Gly) (I) and cyclo(D-Phe-Pro-Gly-Pro{psi}(CSNH)Gly) (II), are reported. The conformations of I and II were analyzed using several 1 and 2D NMR techniques, such as INDOR, temperature and concentration dependence, {sup 1}H-{sup 1}H and {sup 1}H-{sup 13}C COSY, ROESY, and magnetization transfer. Compound I displayed the same general conformation as its parent in CDCl{sub 3}, but the {gamma}-turn hydrogen bond appeared to be weaker, while the {beta}-turn hydrogen bond appeared to be stronger. In DMSO-d{sub 6}, this molecule existed in two conformations in a ratio of 2:1. The major conformer appeared to be the same as that in CDCl{sub 3}, while the second contained at least one cis X-Pro bond, most likely at the Gly{sup 1}-Pro{sup 2} position. Compound II displayed the same conformation as its parent in both solvents. The {gamma}-turn hydrogen bond again appeared to be weaker in CDCl{sub 3}, but comparable with the parent in DMSO-d{sub 6}. Molecular modeling studies of I and II indicated the Pro {psi} angle increased by {approx}6{degree} when a thiocarbonyl was present, thereby reducing steric interactions with the Pro {beta} methylene.

  18. Conformational dynamics of Thermus aquaticus DNA polymerase I during catalysis.

    Science.gov (United States)

    Xu, Cuiling; Maxwell, Brian A; Suo, Zucai

    2014-08-12

    Despite the fact that DNA polymerases have been investigated for many years and are commonly used as tools in a number of molecular biology assays, many details of the kinetic mechanism they use to catalyze DNA synthesis remain unclear. Structural and kinetic studies have characterized a rapid, pre-catalytic open-to-close conformational change of the Finger domain during nucleotide binding for many DNA polymerases including Thermus aquaticus DNA polymerase I (Taq Pol), a thermostable enzyme commonly used for DNA amplification in PCR. However, little has been performed to characterize the motions of other structural domains of Taq Pol or any other DNA polymerase during catalysis. Here, we used stopped-flow Förster resonance energy transfer to investigate the conformational dynamics of all five structural domains of the full-length Taq Pol relative to the DNA substrate during nucleotide binding and incorporation. Our study provides evidence for a rapid conformational change step induced by dNTP binding and a subsequent global conformational transition involving all domains of Taq Pol during catalysis. Additionally, our study shows that the rate of the global transition was greatly increased with the truncated form of Taq Pol lacking the N-terminal domain. Finally, we utilized a mutant of Taq Pol containing a de novo disulfide bond to demonstrate that limiting protein conformational flexibility greatly reduced the polymerization activity of Taq Pol. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Functional Brain Activation Differences in Stuttering Identified with a Rapid fMRI Sequence

    Science.gov (United States)

    Loucks, Torrey; Kraft, Shelly Jo; Choo, Ai Leen; Sharma, Harish; Ambrose, Nicoline G.

    2011-01-01

    The purpose of this study was to investigate whether brain activity related to the presence of stuttering can be identified with rapid functional MRI (fMRI) sequences that involved overt and covert speech processing tasks. The long-term goal is to develop sensitive fMRI approaches with developmentally appropriate tasks to identify deviant speech…

  20. Stratification of nitrification activity in rapid sand filters for drinking water treatment

    DEFF Research Database (Denmark)

    Tatari, Karolina; Smets, Barth F.; Musovic, Sanin

    2013-01-01

    Rapid sand filters used in groundwater treatment remove ammonium, iron and manganese from the water. Ammonium is removed biologically by nitrifying microorganisms attached on the sand surface. Nitrification kinetics and activity is strongly affected by filter design and operation, which are the k...

  1. Interactions of plasminogen activator inhibitor-1 with vitronectin involve an extensive binding surface and induce mutual conformational rearrangements

    DEFF Research Database (Denmark)

    Blouse, Grant E; Dupont, Daniel Miotto; Schar, Christine R

    2009-01-01

    that concomitant structural changes occur as well in native vitronectin. Furthermore, we have measured the effect of vitronectin on the rate of insertion of the reactive center loop into beta-sheet A of PAI-1 during reaction with target proteases. With a variety of PAI-1 variants, we observe that both full......-length vitronectin and the SMB domain have protease-specific effects on the rate of loop insertion but that the two exhibit clearly different effects. These results support a model for PAI-1 binding to vitronectin in which the interaction surface extends beyond the region of PAI-1 occupied by the SMB domain......In order to explore early events during the association of plasminogen activator inhibitor-1 (PAI-1) with its cofactor vitronectin, we have applied a robust strategy that combines protein engineering, fluorescence spectroscopy, and rapid reaction kinetics. Fluorescence stopped-flow experiments...

  2. Total daily activity declines more rapidly with increasing age in older adults.

    Science.gov (United States)

    Buchman, Aron S; Wilson, Robert S; Yu, Lei; James, Bryan D; Boyle, Patricia A; Bennett, David A

    2014-01-01

    Longitudinal studies of objectively measured physical activity are lacking in older adults. We tested whether objective measures of total daily activity decline more rapidly in older adults. This prospective, observational cohort study included 519 community-dwelling older persons from across metropolitan Chicago participating in the Rush Memory and Aging Project. Repeated total daily activity measures (leisure and non-leisure physical activity) were derived from actigraphic recordings for up to 10 days. Generalized estimating equation models which controlled for demographics measures were employed. At baseline, age was inversely related with the level of total daily activity (estimate, -0.014, S.E. 0.002, pdaily activity declined by about 0.070 × 10(5) activity counts/day/yr (estimate -0.065, S.E. 0.005, pdaily activity declined 3% more rapidly for each additional year of age at baseline (estimate -0.002, S.E. 0.001, p=0.027). Thus, total daily activity declined almost twice as fast in an individual 91 years old at baseline versus an individual 71 years old. A higher level of education was associated with a slower rate of decline (estimate 0.004, S.E. 0.002, pdaily activity were unchanged when controlling for baseline level of motor and cognitive function, other late-life activities and chronic health conditions. These data suggest that total daily activity in very old adults declines more rapidly with increasing age. Thus, physical inactivity is likely to become a larger problem in our aging population. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  3. Effects of the substitution of amino acid residues, through chemical synthesis, on the conformation and activity of antimicrobial peptides

    Directory of Open Access Journals (Sweden)

    Regina C. Adão

    2012-06-01

    Full Text Available Antimicrobial peptides make up an assorted group of molecules which contain from 12 to 50 amino acid residues and which may be produced by microorganisms, plants and animals. From the discovery that these biomolecules are lethal to bacteria, inhibiting the pathogenic organism’s growth, and are also related to innate and adapted defense mechanisms, the investigation of such molecules came to be an emergent research field, in which more than 1800 antimicrobial peptides have so far been discovered throughout the last three decades. These molecules are potential representatives of a new generation of antibiotic agents and the main motivation for such use is their activity against a wide variety of pathogens, including Gram-positive and Gram-negative bacteria as well as fungi and viruses. An important class of comprising some of these peptides may be found in anurans, from which it has been isolated, a considerable number of antimicrobial peptides with diverse sequences and structures, including linear and dimeric ones. In this work monomeric chains (CH1 e CH2 of the heterodimeric antimicrobial peptide distinctin (isolated in 1999 from Phyllomedusa distincta anurans, as well as its mutated monomers (CH1-S and CH2-S and the heterodimer itself were synthesized. The distinctin is the peptide with two chains of different sequences (Table 1 bound each other by disulfide bond from the cystein residues constituting the heterodimer. To investigate the effects on the biological activity by amino acids substitution at normal distinctin CH1 and CH2 chains, both were synthesized as well as their similar chains (CH1-S and CH2-S in which the cystein (Fig.1 a residues of each chain were changed by serin residues (Fig. 1 b. The new chains were named mutants. The synthesis was carried out in solid phase, using Fmoc strategy. The heterodimer distinctin was obtained from CH1 and CH2 chains coupling through cystein residues air oxidation. The results from HPLC

  4. Logarithmic exotic conformal Galilean algebras

    Energy Technology Data Exchange (ETDEWEB)

    Henkel, Malte, E-mail: Malte.henkel@univ-lorraine.fr [Groupe de Physique Statistique, Institut Jean Lamour (CNRS UMR 7198), Université de Lorraine Nancy, B.P. 70239, F-54506 Vandoeuvre-lès-Nancy Cedex (France); Hosseiny, Ali, E-mail: al_hosseiny@sbu.ac.ir [Department of Physics, Shahid Beheshti University, G.C. Evin, Tehran 19839 (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Rouhani, Shahin, E-mail: rouhani@ipm.ir [Department of Physics, Sharif University of Technology, P.O. Box 11165-9161, Tehran (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

    2014-02-15

    Logarithmic representations of the conformal Galilean algebra (CGA) and the Exotic Conformal Galilean algebra (ECGA) are constructed. This can be achieved by non-decomposable representations of the scaling dimensions or the rapidity indices, specific to conformal Galilean algebras. Logarithmic representations of the non-exotic CGA lead to the expected constraints on scaling dimensions and rapidities and also on the logarithmic contributions in the co-variant two-point functions. On the other hand, the ECGA admits several distinct situations which are distinguished by different sets of constraints and distinct scaling forms of the two-point functions. Two distinct realisations for the spatial rotations are identified as well. This is the first concrete example of a reducible, but non-decomposable representation, without logarithmic terms. Such cases had been anticipated before.

  5. Optogenetic Activation of the Sublaterodorsal (SLD) Nucleus Induces Rapid Muscle Inhibition

    Science.gov (United States)

    2015-09-01

    and neural activity, as measured with electroencephalography ( EEG ). One of the hallmarks of rapid eye movement (REM) sleep is muscle inhibition and is...than the prior studies previously cited that relied on pharmaceuticals to induce REM sleep . Building on this known literature, we have generated pilot... sleep /wake component we may need to alter our experimental paradigm and test whether we can influence EEG activity after the animal is already in SWS

  6. The tertiary origin of the allosteric activation of E. coli glucosamine-6-phosphate deaminase studied by sol-gel nanoencapsulation of its T conformer.

    Directory of Open Access Journals (Sweden)

    Sergio Zonszein

    Full Text Available The role of tertiary conformational changes associated to ligand binding was explored using the allosteric enzyme glucosamine-6-phosphate (GlcN6P deaminase from Escherichia coli (EcGNPDA as an experimental model. This is an enzyme of amino sugar catabolism that deaminates GlcN6P, giving fructose 6-phosphate and ammonia, and is allosterically activated by N-acetylglucosamine 6-phosphate (GlcNAc6P. We resorted to the nanoencapsulation of this enzyme in wet silica sol-gels for studying the role of intrasubunit local mobility in its allosteric activation under the suppression of quaternary transition. The gel-trapped enzyme lost its characteristic homotropic cooperativity while keeping its catalytic properties and the allosteric activation by GlcNAc6P. The nanoencapsulation keeps the enzyme in the T quaternary conformation, making possible the study of its allosteric activation under a condition that is not possible to attain in a soluble phase. The involved local transition was slowed down by nanoencapsulation, thus easing the fluorometric analysis of its relaxation kinetics, which revealed an induced-fit mechanism. The absence of cooperativity produced allosterically activated transitory states displaying velocity against substrate concentration curves with apparent negative cooperativity, due to the simultaneous presence of subunits with different substrate affinities. Reaction kinetics experiments performed at different tertiary conformational relaxation times also reveal the sequential nature of the allosteric activation. We assumed as a minimal model the existence of two tertiary states, t and r, of low and high affinity, respectively, for the substrate and the activator. By fitting the velocity-substrate curves as a linear combination of two hyperbolic functions with Kt and Kr as KM values, we obtained comparable values to those reported for the quaternary conformers in solution fitted to MWC model. These results are discussed in the

  7. Molecular dynamics simulations of the conformational behaviour of the synthetic dipeptide PIDOTIMOD, a new immunostimulating agent

    Science.gov (United States)

    Villani, Vincenzo; Pucciariello, Rachele

    1994-01-01

    Molecular dynamics (MD) simulations of the conformational behaviour of the conformers of PIDOTIMOD, an interleukin-2 lymphocytes T receptor agonist dipeptide, have been carried out. MD simulation at constant temperature of 300 and 400 K and constant total energy runs at high temperatures have been performed, and trajectories and statistical properties of motions investigated. At 300 K two trans and one cis conformer were found to be dynamically stable. Two puckered forms of the oxo-prolyl ring in rapid equilibrium have been detected. The equilibrium conformations appear rather rigid and poor in H-bonds. At 400 K both trans and cis conformers are thermally mixed. At high temperature large fluctuations of the peptide bond between the oxo-prolyl and thyazolidin rings are observed. Nevertheless in the short time scale trans—cis interconversion does not occur. Suggestions on the nature of the structure—activity relationship are made

  8. Rapid direct methods for enumeration of specific, active bacteria in water and biofilms

    Science.gov (United States)

    McFeters, G. A.; Pyle, B. H.; Lisle, J. T.; Broadaway, S. C.

    1999-01-01

    Conventional methods for detecting indicator and pathogenic bacteria in water may underestimate the actual population due to sublethal environmental injury, inability of the target bacteria to take up nutrients and other physiological factors which reduce bacterial culturability. Rapid and direct methods are needed to more accurately detect and enumerate active bacteria. Such a methodological advance would provide greater sensitivity in assessing the microbiological safety of water and food. The principle goal of this presentation is to describe novel approaches we have formulated for the rapid and simultaneous detection of bacteria plus the determination of their physiological activity in water and other environmental samples. The present version of our method involves the concentration of organisms by membrane filtration or immunomagnetic separation and combines an intracellular fluorochrome (CTC) for assessment of respiratory activity plus fluorescent-labelled antibody detection of specific bacteria. This approach has also been successfully used to demonstrate spatial and temporal heterogeneities of physiological activities in biofilms when coupled with cryosectioning. Candidate physiological stains include those capable of determining respiratory activity, membrane potential, membrane integrity, growth rate and cellular enzymatic activities. Results obtained thus far indicate that immunomagnetic separation can provide a high degree of sensitivity in the recovery of seeded target bacteria (Escherichia coli O157:H7) in water and hamburger. The captured and stained target bacteria are then enumerated by either conventional fluorescence microscopy or ChemScan(R), a new instrument that is very sensitive and rapid. The ChemScan(R) laser scanning instrument (Chemunex, Paris, France) provides the detection of individual fluorescently labelled bacterial cells using three emission channels in less than 5 min. A high degree of correlation has been demonstrated between

  9. Crystal Structure of Mouse Thymidylate Synthase in Tertiary Complex with dUMP and Raltitrexed Reveals N-Terminus Architecture and Two Different Active Site Conformations

    Directory of Open Access Journals (Sweden)

    Anna Dowierciał

    2014-01-01

    Full Text Available The crystal structure of mouse thymidylate synthase (mTS in complex with substrate dUMP and antifolate inhibitor Raltitrexed is reported. The structure reveals, for the first time in the group of mammalian TS structures, a well-ordered segment of 13 N-terminal amino acids, whose ordered conformation is stabilized due to specific crystal packing. The structure consists of two homodimers, differing in conformation, one being more closed (dimer AB and thus supporting tighter binding of ligands, and the other being more open (dimer CD and thus allowing weaker binding of ligands. This difference indicates an asymmetrical effect of the binding of Raltitrexed to two independent mTS molecules. Conformational changes leading to a ligand-induced closing of the active site cleft are observed by comparing the crystal structures of mTS in three different states along the catalytic pathway: ligand-free, dUMP-bound, and dUMP- and Raltitrexed-bound. Possible interaction routes between hydrophobic residues of the mTS protein N-terminal segment and the active site are also discussed.

  10. Crystal structure of mouse thymidylate synthase in tertiary complex with dUMP and raltitrexed reveals N-terminus architecture and two different active site conformations.

    Science.gov (United States)

    Dowierciał, Anna; Wilk, Piotr; Rypniewski, Wojciech; Rode, Wojciech; Jarmuła, Adam

    2014-01-01

    The crystal structure of mouse thymidylate synthase (mTS) in complex with substrate dUMP and antifolate inhibitor Raltitrexed is reported. The structure reveals, for the first time in the group of mammalian TS structures, a well-ordered segment of 13 N-terminal amino acids, whose ordered conformation is stabilized due to specific crystal packing. The structure consists of two homodimers, differing in conformation, one being more closed (dimer AB) and thus supporting tighter binding of ligands, and the other being more open (dimer CD) and thus allowing weaker binding of ligands. This difference indicates an asymmetrical effect of the binding of Raltitrexed to two independent mTS molecules. Conformational changes leading to a ligand-induced closing of the active site cleft are observed by comparing the crystal structures of mTS in three different states along the catalytic pathway: ligand-free, dUMP-bound, and dUMP- and Raltitrexed-bound. Possible interaction routes between hydrophobic residues of the mTS protein N-terminal segment and the active site are also discussed.

  11. Conformational changes in guanylate cyclase-activating protein 1 (GCAP1) induced by Ca2+ and N-terminal fatty acid acylation

    Science.gov (United States)

    Orban, Tivadar; Bereta, Grzegorz; Miyagi, Masaru; Wang, Benlian; Chance, Mark R.; Sousa, Marcelo Carlos; Palczewski, Krzysztof

    2010-01-01

    Neuronal Ca2+ sensors (NCS) are high affinity Ca2+-binding proteins critical for regulating a vast range of physiological processes. Guanylate cyclase-activating proteins (GCAPs) are members of the NCS family responsible for activating retinal guanylate cyclases (GCs) at low Ca2+ concentrations, triggering synthesis of cGMP and recovery of photoreceptor cells to the dark-adapted state. Here we use amide hydrogen-deuterium exchange and radiolytic labeling, and molecular dynamics simulations to study conformational changes induced by Ca2+ and modulated by the N-terminal myristoyl group. Our data on the conformational dynamics of GCAP1 in solution suggest that Ca2+ stabilizes the protein but induces relatively small changes in the domain structure; however, loss of Ca+2 mediates a significant global relaxation and movement of N- and C-terminal domains. This model and the previously described “calcium-myristoyl switch” proposed for recoverin indicate significant diversity in conformational changes among these highly homologous NCS proteins with distinct functions. PMID:20152158

  12. Dimensions of the ion channel in neuronal nicotinic acetylcholine receptor as estimated from analysis of conformation-activity relationships of open-channel blocking drugs.

    Science.gov (United States)

    Zhorov, B S; Brovtsyna, N B; Gmiro, V E; Lukomskaya NYa; Serdyuk, S E; Potapyeva, N N; Magazanik, L G; Kurenniy, D E; Skok, V I

    1991-04-01

    Relationship between the size of the molecule in the series of organic ions Et3+N--(CH2)5--+NR1R2R3 (Ri--alkyl or cycloalkyl substituents) and their abilities to block nicotinic acetylcholine receptors (AChRs) due to their open-channel blockade in the neurons of autonomic ganglia and in frog end-plate was analyzed. All low-energy equilibrium conformations of the drugs were calculated by the molecular mechanics method. A unique rectangular channel profile 6.1 x 8.3 A, for which the best correlation between blocking activity of the drugs and total population of their conformations being able to penetrate into the channel, was deduced from all those tested.

  13. Thermal-induced conformational changes in the product release area drive the enzymatic activity of xylanases 10B: Crystal structure, conformational stability and functional characterization of the xylanase 10B from Thermotoga petrophila RKU-1

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Camila Ramos; Meza, Andreia Navarro [Laboratorio Nacional de Biociencias (LNBio), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Hoffmam, Zaira Bruna; Silva, Junio Cota; Alvarez, Thabata Maria; Ruller, Roberto [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Giesel, Guilherme Menegon; Verli, Hugo [Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Squina, Fabio Marcio [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Prade, Rolf Alexander [Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK (United States); Murakami, Mario Tyago, E-mail: mario.murakami@lnbio.org.br [Laboratorio Nacional de Biociencias (LNBio), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil)

    2010-12-10

    Research highlights: {yields} The hyperthermostable xylanase 10B from Thermotoga petrophila RKU-1 produces exclusively xylobiose at the optimum temperature. {yields} Circular dichroism spectroscopy suggests a coupling effect of temperature-induced structural changes with its enzymatic behavior. {yields} Crystallographic and molecular dynamics studies indicate that conformational changes in the product release area modulate the enzyme action mode. -- Abstract: Endo-xylanases play a key role in the depolymerization of xylan and recently, they have attracted much attention owing to their potential applications on biofuels and paper industries. In this work, we have investigated the molecular basis for the action mode of xylanases 10B at high temperatures using biochemical, biophysical and crystallographic methods. The crystal structure of xylanase 10B from hyperthermophilic bacterium Thermotoga petrophila RKU-1 (TpXyl10B) has been solved in the native state and in complex with xylobiose. The complex crystal structure showed a classical binding mode shared among other xylanases, which encompasses the -1 and -2 subsites. Interestingly, TpXyl10B displayed a temperature-dependent action mode producing xylobiose and xylotriose at 20 {sup o}C, and exclusively xylobiose at 90 {sup o}C as assessed by capillary zone electrophoresis. Moreover, circular dichroism spectroscopy suggested a coupling effect of temperature-induced structural changes with this particular enzymatic behavior. Molecular dynamics simulations supported the CD analysis suggesting that an open conformational state adopted by the catalytic loop (Trp297-Lys326) provokes significant modifications in the product release area (+1,+2 and +3 subsites), which drives the enzymatic activity to the specific release of xylobiose at high temperatures.

  14. A rapid and sensitive method for measuring N-acetylglucosaminidase activity in cultured cells.

    Directory of Open Access Journals (Sweden)

    Victor Mauri

    Full Text Available A rapid and sensitive method to quantitatively assess N-acetylglucosaminidase (NAG activity in cultured cells is highly desirable for both basic research and clinical studies. NAG activity is deficient in cells from patients with Mucopolysaccharidosis type IIIB (MPS IIIB due to mutations in NAGLU, the gene that encodes NAG. Currently available techniques for measuring NAG activity in patient-derived cell lines include chromogenic and fluorogenic assays and provide a biochemical method for the diagnosis of MPS IIIB. However, standard protocols require large amounts of cells, cell disruption by sonication or freeze-thawing, and normalization to the cellular protein content, resulting in an error-prone procedure that is material- and time-consuming and that produces highly variable results. Here we report a new procedure for measuring NAG activity in cultured cells. This procedure is based on the use of the fluorogenic NAG substrate, 4-Methylumbelliferyl-2-acetamido-2-deoxy-alpha-D-glucopyranoside (MUG, in a one-step cell assay that does not require cell disruption or post-assay normalization and that employs a low number of cells in 96-well plate format. We show that the NAG one-step cell assay greatly discriminates between wild-type and MPS IIIB patient-derived fibroblasts, thus providing a rapid method for the detection of deficiencies in NAG activity. We also show that the assay is sensitive to changes in NAG activity due to increases in NAGLU expression achieved by either overexpressing the transcription factor EB (TFEB, a master regulator of lysosomal function, or by inducing TFEB activation chemically. Because of its small format, rapidity, sensitivity and reproducibility, the NAG one-step cell assay is suitable for multiple procedures, including the high-throughput screening of chemical libraries to identify modulators of NAG expression, folding and activity, and the investigation of candidate molecules and constructs for applications in

  15. Structure of the complex between trypanosomal triosephosphate isomerase and N-hydroxy-4-phosphono-butanamide: binding at the active site despite an "open" flexible loop conformation.

    OpenAIRE

    Verlinde, C L; Witmans, C. J.; Pijning, T; Kalk, K.H.; Hol, W.G.; Callens, M; Opperdoes, Frederik

    1992-01-01

    The structure of triosephosphate isomerase from Trypanosoma brucei complexed with the competitive inhibitor N-hydroxy-4-phosphono-butanamide was determined by X-ray crystallography to a resolution of 2.84 A. Full occupancy binding of the inhibitor is observed only at one of the active sites of the homodimeric enzyme where the flexible loop is locked in a completely open conformation by crystal contacts. There is evidence that the inhibitor also binds to the second active site of the enzyme, b...

  16. Conformation and catalytic activity of nickel-carbon cluster for ethanol dissociation in carbon nanotube synthesis: Ab initio molecular dynamics simulation

    Science.gov (United States)

    Fukuhara, Satoru; Shimojo, Fuyuki; Shibuta, Yasushi

    2017-07-01

    Conformation and catalytic activity of nickel-carbon binary clusters are investigated to shed light on important questions on the carbon nanotube growth. Carbon atoms tend to stay at the surface of the binary cluster and form carbon chains with increasing carbon concentration. The binary clusters have lower catalytic activity for ethanol dehydrogenation compared to pure nickel clusters due to the strong electron negativity of carbon atoms. Moreover, the Csbnd C bond dissociation in typical fragment molecules, which is a key reaction of carbon nanotube growth via alcohol CVD, is inhibited on the binary cluster due to the increase of the backward reaction.

  17. The R1275Q neuroblastoma mutant and certain ATP-competitive inhibitors stabilize alternative activation loop conformations of anaplastic lymphoma kinase.

    Science.gov (United States)

    Epstein, Linda F; Chen, Hao; Emkey, Renee; Whittington, Douglas A

    2012-10-26

    Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase that, when genetically altered by mutation, amplification, chromosomal translocation or inversion, has been shown to play an oncogenic role in certain cancers. Small molecule inhibitors targeting the kinase activity of ALK have proven to be effective therapies in certain ALK-driven malignancies and one such inhibitor, crizotinib, is now approved for the treatment of EML4-ALK-driven, non-small cell lung cancer. In neuroblastoma, activating point mutations in the ALK kinase domain can drive disease progression, with the two most common mutations being F1174L and R1275Q. We report here crystal structures of the ALK kinase domain containing the F1174L and R1275Q mutations. Also included are crystal structures of ALK in complex with novel small molecule ALK inhibitors, including a classic type II inhibitor, that stabilize previously unobserved conformations of the ALK activation loop. Collectively, these structures illustrate a different series of activation loop conformations than has been observed in previous ALK crystal structures and provide insight into the activating nature of the R1275Q mutation. The novel active site topologies presented here may also aid the structure-based drug design of a new generation of ALK inhibitors.

  18. Short-time dynamics of pH-dependent conformation and substrate binding in the active site of beta-glucosidases: A computational study.

    Science.gov (United States)

    Flannelly, David F; Aoki, Thalia G; Aristilde, Ludmilla

    2015-09-01

    The complete degradation of cellulose to glucose is essential to carbon turnover in terrestrial ecosystems and to engineered biofuel production. A rate-limiting step in this pathway is catalyzed by beta-glucosidase (BG) enzymes, which convert cellulobiose into two glucose molecules. The activity of these enzymes has been shown to vary with solution pH. However, it is not well understood how pH influences the enzyme conformation required for catalytic action on the substrate. A structural understanding of this pH effect is important for predicting shifts in BG activity in bioreactors and environmental matrices, in addition to informing targeted protein engineering. Here we applied molecular dynamics simulations to explore conformational and substrate binding dynamics in two well-characterized BGs of bacterial (Clostridium cellulovorans) and fungal (Trichoderma reesei) origins as a function of pH. The enzymes were simulated in an explicit solvated environment, with NaCl as electrolytes, at their prominent ionization states obtained at pH 5, 6, 7, and 7.5. Our findings indicated that pH-dependent changes in the ionization states of non-catalytic residues localized outside of the immediate active site led to pH-dependent disruption of the active site conformation. This disruption interferes with favorable H-bonding interactions with catalytic residues required to initiate catalysis on the substrate. We also identified specific non-catalytic residues that are involved in stabilizing the substrate at the optimal pH for enzyme activity. The simulations further revealed the dynamics of water-bridging interactions both outside and inside the substrate binding cleft during structural changes in the enzyme-substrate complex. These findings provide new structural insights into the pH-dependent substrate binding specificity in BGs. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. A Rapid Method for Measuring Strontium-90 Activity in Crops in China

    Directory of Open Access Journals (Sweden)

    Pan Lingjing Pan

    2017-01-01

    Full Text Available A rapid method for measuring Sr-90 activity in crop ashes is presented. Liquid scintillation counting, combined with ion exchange columns 4‘, 4“(5“-di-t-butylcyclohexane-18-crown-6, is used to determine the activity of Sr-90 in crops. The yields of chemical procedure are quantified using gravimetric analysis. The conventional method that uses ion-exchange resin with HDEHP could not completely remove all the bismuth when comparatively large lead and bismuth exist in the samples. This is overcome by the rapid method. The chemical yield of this method is about 60% and the MDA for Sr-90 is found to be 2:32 Bq/kg. The whole procedure together with using spectrum analysis to determine the activity only takes about one day, which is really a large improvement compared with the conventional method. A modified conventional method is also described here to verify the value of the rapid one. These two methods can meet di_erent needs of daily monitoring and emergency situation.

  20. A Rapid Method for Measuring Strontium-90 Activity in Crops in China

    Science.gov (United States)

    Pan, Lingjing Pan; Yu, Guobing; Wen, Deyun; Chen, Zhi; Sheng, Liusi; Liu, Chung-King; Xu, X. George

    2017-09-01

    A rapid method for measuring Sr-90 activity in crop ashes is presented. Liquid scintillation counting, combined with ion exchange columns 4`, 4"(5")-di-t-butylcyclohexane-18-crown-6, is used to determine the activity of Sr-90 in crops. The yields of chemical procedure are quantified using gravimetric analysis. The conventional method that uses ion-exchange resin with HDEHP could not completely remove all the bismuth when comparatively large lead and bismuth exist in the samples. This is overcome by the rapid method. The chemical yield of this method is about 60% and the MDA for Sr-90 is found to be 2:32 Bq/kg. The whole procedure together with using spectrum analysis to determine the activity only takes about one day, which is really a large improvement compared with the conventional method. A modified conventional method is also described here to verify the value of the rapid one. These two methods can meet di_erent needs of daily monitoring and emergency situation.

  1. Ataxia Telangiectasia-Mutated (ATM) Kinase Activity Is Regulated by ATP-driven Conformational Changes in the Mre11/Rad50/Nbs1 (MRN) Complex*

    Science.gov (United States)

    Lee, Ji-Hoon; Mand, Michael R.; Deshpande, Rajashree A.; Kinoshita, Eri; Yang, Soo-Hyun; Wyman, Claire; Paull, Tanya T.

    2013-01-01

    The Ataxia Telangiectasia-Mutated (ATM) protein kinase is recruited to sites of double-strand DNA breaks by the Mre11/Rad50/Nbs1 (MRN) complex, which also facilitates ATM monomerization and activation. MRN exists in at least two distinct conformational states, dependent on ATP binding and hydrolysis by the Rad50 protein. Here we use an ATP analog-sensitive form of ATM to determine that ATP binding, but not hydrolysis, by Rad50 is essential for MRN stimulation of ATM. Mre11 nuclease activity is dispensable, although some mutations in the Mre11 catalytic domain block ATM activation independent of nuclease function, as does the mirin compound. The coiled-coil domains of Rad50 are important for the DNA binding ability of MRN and are essential for ATM activation, but loss of the zinc hook connection can be substituted by higher levels of the complex. Nbs1 binds to the “closed” form of the MR complex, promoted by the zinc hook and by ATP binding. Thus the primary role of the hook is to tether Rad50 monomers together, promoting the association of the Rad50 catalytic domains into a form that binds ATP and also binds Nbs1. Collectively, these results show that the ATP-bound form of MRN is the critical conformation for ATM activation. PMID:23525106

  2. Ataxia telangiectasia-mutated (ATM) kinase activity is regulated by ATP-driven conformational changes in the Mre11/Rad50/Nbs1 (MRN) complex.

    Science.gov (United States)

    Lee, Ji-Hoon; Mand, Michael R; Deshpande, Rajashree A; Kinoshita, Eri; Yang, Soo-Hyun; Wyman, Claire; Paull, Tanya T

    2013-05-03

    The Ataxia Telangiectasia-Mutated (ATM) protein kinase is recruited to sites of double-strand DNA breaks by the Mre11/Rad50/Nbs1 (MRN) complex, which also facilitates ATM monomerization and activation. MRN exists in at least two distinct conformational states, dependent on ATP binding and hydrolysis by the Rad50 protein. Here we use an ATP analog-sensitive form of ATM to determine that ATP binding, but not hydrolysis, by Rad50 is essential for MRN stimulation of ATM. Mre11 nuclease activity is dispensable, although some mutations in the Mre11 catalytic domain block ATM activation independent of nuclease function, as does the mirin compound. The coiled-coil domains of Rad50 are important for the DNA binding ability of MRN and are essential for ATM activation, but loss of the zinc hook connection can be substituted by higher levels of the complex. Nbs1 binds to the "closed" form of the MR complex, promoted by the zinc hook and by ATP binding. Thus the primary role of the hook is to tether Rad50 monomers together, promoting the association of the Rad50 catalytic domains into a form that binds ATP and also binds Nbs1. Collectively, these results show that the ATP-bound form of MRN is the critical conformation for ATM activation.

  3. The VPS-20 subunit of the endosomal sorting complex ESCRT-III exhibits an open conformation in the absence of upstream activation.

    Science.gov (United States)

    Schuh, Amber L; Hanna, Michael; Quinney, Kyle; Wang, Lei; Sarkeshik, Ali; Yates, John R; Audhya, Anjon

    2015-03-15

    Members of the endosomal sorting complex required for transport (ESCRT) machinery function in membrane remodelling processes during multivesicular endosome (MVE) biogenesis, cytokinesis, retroviral budding and plasma membrane repair. During luminal vesicle formation at endosomes, the ESCRT-II complex and the ESCRT-III subunit vacuolar protein sorting (VPS)-20 play a specific role in regulating assembly of ESCRT-III filaments, which promote vesicle scission. Previous work suggests that Vps20 isoforms, like other ESCRT-III subunits, exhibits an auto-inhibited closed conformation in solution and its activation depends on an association with ESCRT-II specifically at membranes [1]. However, we show in the present study that Caenorhabditis elegans ESCRT-II and VPS-20 interact directly in solution, both in cytosolic cell extracts and in using recombinant proteins in vitro. Moreover, we demonstrate that purified VPS-20 exhibits an open extended conformation, irrespective of ESCRT-II binding, in contrast with the closed auto-inhibited architecture of another ESCRT-III subunit, VPS-24. Our data argue that individual ESCRT-III subunits adopt distinct conformations, which are tailored for their specific functions during ESCRT-mediated membrane reorganization events.

  4. Conformational stability and activity analysis of two hydroxymethylbilane synthase mutants, K132N and V215E, with different phenotypic association with acute intermittent porphyria

    Science.gov (United States)

    Bustad, Helene J.; Vorland, Marta; Rønneseth, Eva; Sandberg, Sverre; Martinez, Aurora; Toska, Karen

    2013-01-01

    The autosomal dominantly inherited disease AIP (acute intermittent porphyria) is caused by mutations in HMBS [hydroxymethylbilane synthase; also known as PBG (porphobilinogen) deaminase], the third enzyme in the haem biosynthesis pathway. Enzyme-intermediates with increasing number of PBG molecules are formed during the catalysis of HMBS. In this work, we studied the two uncharacterized mutants K132N and V215E comparative with wt (wild-type) HMBS and to the previously reported AIP-associated mutants R116W, R167W and R173W. These mainly present defects in conformational stability (R116W), enzyme kinetics (R167W) or both (R173W). A combination of native PAGE, CD, DSF (differential scanning fluorimetry) and ion-exchange chromatography was used to study conformational stability and activity of the recombinant enzymes. We also investigated the distribution of intermediates corresponding to specific elongation stages. It is well known that the thermostability of HMBS increases when the DPM (dipyrromethane) cofactor binds to the apoenzyme and the holoenzyme is formed. Interestingly, a decrease in thermal stability was measured concomitant to elongation of the pyrrole chain, indicating a loosening of the structure prior to product release. No conformational or kinetic defect was observed for the K132N mutant, whereas V215E presented lower conformational stability and probably a perturbed elongation process. This is in accordance with the high association of V215E with AIP. Our results contribute to interpret the molecular mechanisms for dysfunction of HMBS mutants and to establish genotype–phenotype relations for AIP. PMID:23815679

  5. Rapid kinetic BRET measurements to monitor G protein activation by GPCR and non-GPCR proteins.

    Science.gov (United States)

    Maziarz, Marcin; Garcia-Marcos, Mikel

    2017-01-01

    Heterotrimeric G proteins are central hubs of signal transduction whose activity is controlled by G protein-coupled receptors (GPCRs) as well as by a complex network of regulatory proteins. Recently, bioluminescence resonance energy transfer (BRET)-based assays have been used to monitor real-time activation of heterotrimeric G proteins in cells. Here we describe the use of a previously established BRET assay to monitor G protein activation upon GPCR stimulation and its adaptation to measure G protein activation by non-GPCR proteins, such as by cytoplasmic guanine nucleotide exchange factors (GEFs) like GIV/Girdin. The BRET assay monitors the release of free Gβγ from Gα-Gβγ heterotrimers as a readout of G protein activation, which is readily observable upon agonist stimulation of GPCRs. To control the signal input for non-GPCR activators, we describe the use of a chemically induced dimerization strategy to promote rapid membrane translocation of proteins containing the Gα-binding and -activating (GBA) motif found in some nonreceptor GEFs. The assay described here allows the kinetic measurement of G protein activation with subsecond temporal resolution and to compare the levels of activation induced by GPCR agonists vs those induced by the membrane recruitment of nonreceptor G protein signaling activators. © 2017 Elsevier Inc. All rights reserved.

  6. Rapid Detection of Glycogen Synthase Kinase-3 Activity in Mouse Sperm Using Fluorescent Gel Shift Electrophoresis.

    Science.gov (United States)

    Choi, Hoseok; Choi, Bomi; Seo, Ju Tae; Lee, Kyung Jin; Gye, Myung Chan; Kim, Young-Pil

    2016-04-16

    Assaying the glycogen synthase kinase-3 (GSK3) activity in sperm is of great importance because it is closely implicated in sperm motility and male infertility. While a number of studies on GSK3 activity have relied on labor-intensive immunoblotting to identify phosphorylated GSK3, here we report the simple and rapid detection of GSK3 activity in mouse sperm using conventional agarose gel electrophoresis and a fluorescent peptide substrate. When a dye-tethered and prephosphorylated (primed) peptide substrate for GSK3 was employed, a distinct mobility shift in the fluorescent bands on the agarose was observed by GSK3-induced phosphorylation of the primed peptides. The GSK3 activity in mouse testes and sperm were quantifiable by gel shift assay with low sample consumption and were significantly correlated with the expression levels of GSK3 and p-GSK3. We suggest that our assay can be used for reliable and rapid detection of GSK3 activity in cells and tissue extracts.

  7. Rapid Detection of Glycogen Synthase Kinase-3 Activity in Mouse Sperm Using Fluorescent Gel Shift Electrophoresis

    Directory of Open Access Journals (Sweden)

    Hoseok Choi

    2016-04-01

    Full Text Available Assaying the glycogen synthase kinase-3 (GSK3 activity in sperm is of great importance because it is closely implicated in sperm motility and male infertility. While a number of studies on GSK3 activity have relied on labor-intensive immunoblotting to identify phosphorylated GSK3, here we report the simple and rapid detection of GSK3 activity in mouse sperm using conventional agarose gel electrophoresis and a fluorescent peptide substrate. When a dye-tethered and prephosphorylated (primed peptide substrate for GSK3 was employed, a distinct mobility shift in the fluorescent bands on the agarose was observed by GSK3-induced phosphorylation of the primed peptides. The GSK3 activity in mouse testes and sperm were quantifiable by gel shift assay with low sample consumption and were significantly correlated with the expression levels of GSK3 and p-GSK3. We suggest that our assay can be used for reliable and rapid detection of GSK3 activity in cells and tissue extracts.

  8. Virus-associated activation of innate immunity induces rapid disruption of Peyer's patches in mice.

    Science.gov (United States)

    Heidegger, Simon; Anz, David; Stephan, Nicolas; Bohn, Bernadette; Herbst, Tina; Fendler, Wolfgang Peter; Suhartha, Nina; Sandholzer, Nadja; Kobold, Sebastian; Hotz, Christian; Eisenächer, Katharina; Radtke-Schuller, Susanne; Endres, Stefan; Bourquin, Carole

    2013-10-10

    Early in the course of infection, detection of pathogen-associated molecular patterns by innate immune receptors can shape the subsequent adaptive immune response. Here we investigate the influence of virus-associated innate immune activation on lymphocyte distribution in secondary lymphoid organs. We show for the first time that virus infection of mice induces rapid disruption of the Peyer's patches but not of other secondary lymphoid organs. The observed effect was not dependent on an active infectious process, but due to innate immune activation and could be mimicked by virus-associated molecular patterns such as the synthetic double-stranded RNA poly(I:C). Profound histomorphologic changes in Peyer's patches were associated with depletion of organ cellularity, most prominent among the B-cell subset. We demonstrate that the disruption is entirely dependent on type I interferon (IFN). At the cellular level, we show that virus-associated immune activation by IFN-α blocks B-cell trafficking to the Peyer's patches by downregulating expression of the homing molecule α4β7-integrin. In summary, our data identify a mechanism that results in type I IFN-dependent rapid but reversible disruption of intestinal lymphoid organs during systemic viral immune activation. We propose that such rerouted lymphocyte trafficking may impact the development of B-cell immunity to systemic viral pathogens.

  9. Analysis of α-glucosidase enzyme activity used in a rapid test for steam sterilization assurance.

    Science.gov (United States)

    Setlow, B; Korza, G; Setlow, P

    2016-05-01

    This study was to determine the sources, location and identity of α-glucosidases in dormant/germinating/outgrowing spores and growing cells of Geobacillus stearothermophilus ATCC 7953, an enzymatic activity in spores used in rapid tests of steam sterilization. α-Glucosidase activity in spores and cells was determined measuring methylumbelliferyl-α-d-glucoside (α-MUG) or α-MUG-6-phosphate hydrolysis fluorometrically. While α-MUG-6-phosphate was not hydrolysed by cell or spore extracts, assays with α-MUG showed that: (1) the α-glucosidase activity was inside and outside spores, and the activity outside spores was largely removed by buffer washes or heat activation, whereas α-glucosidase activity was only inside vegetative cells; (2) most α-glucosidase activity in cells and spores was soluble; (3) Western blots and enzyme inhibition using an anti-α-glucosidase antiserum identified ≥2 α-glucosidases in spores and growing cells; (4) α-glucosidase-specific activities were similar in dormant, germinated and outgrowing spore and growing cell extracts; and (5) significant α-glucosidase was synthesized during spore germination and outgrowth and cell growth, this synthesis was not repressed by glucose nor induced by α-MUG, but glucose inhibited α-MUG uptake. α-MUG hydrolysis by G. stearothermophilus is by α-MUG uptake and hydrolysis by ≥2 α-glucosidases associated with dormant spores and synthesized by germinating and outgrowing spores. The enzyme activity observed by sterilization assurance assays appears likely to come from heat-stable enzyme in the spore core and enzyme(s) synthesized in spore outgrowth. The results of this work provide new insight into the science behind a rapid test for steam sterilization assurance. © 2016 The Society for Applied Microbiology.

  10. Impact of an extruded nucleotide on cleavage activity and dynamic catalytic core conformation of the hepatitis delta virus ribozyme

    Czech Academy of Sciences Publication Activity Database

    Šefčíková, J.; Krasovská, Maryna V.; Špačková, Naďa; Šponer, Jiří; Walter, N.G.

    2007-01-01

    Roč. 85, 5-6 (2007), s. 392-406 ISSN 0006-3525 R&D Projects: GA ČR(CZ) GA203/05/0388; GA ČR(CZ) GA203/05/0009; GA AV ČR(CZ) 1QS500040581; GA MŠk(CZ) LC512 Institutional research plan: CEZ:AV0Z50040702 Keywords : conformational dynamics * hepatitis delta virus * molecular dynamics Subject RIV: BO - Biophysics Impact factor: 2.389, year: 2007

  11. Structural studies unravel the active conformation of apo RORγt nuclear receptor and a common inverse agonism of two diverse classes of RORγt inhibitors.

    Science.gov (United States)

    Li, Xiang; Anderson, Marie; Collin, Delphine; Muegge, Ingo; Wan, John; Brennan, Debra; Kugler, Stanley; Terenzio, Donna; Kennedy, Charles; Lin, Siqi; Labadia, Mark E; Cook, Brian; Hughes, Robert; Farrow, Neil A

    2017-07-14

    The nuclear receptor retinoid acid receptor-related orphan receptor γt (RORγt) is a master regulator of the Th17/IL-17 pathway that plays crucial roles in the pathogenesis of autoimmunity. RORγt has recently emerged as a highly promising target for treatment of a number of autoimmune diseases. Through high-throughput screening, we previously identified several classes of inverse agonists for RORγt. Here, we report the crystal structures for the ligand-binding domain of RORγt in both apo and ligand-bound states. We show that apo RORγt adopts an active conformation capable of recruiting coactivator peptides and present a detailed analysis of the structural determinants that stabilize helix 12 (H12) of RORγt in the active state in the absence of a ligand. The structures of ligand-bound RORγt reveal that binding of the inverse agonists disrupts critical interactions that stabilize H12. This destabilizing effect is supported by ab initio calculations and experimentally by a normalized crystallographic B-factor analysis. Of note, the H12 destabilization in the active state shifts the conformational equilibrium of RORγt toward an inactive state, which underlies the molecular mechanism of action for the inverse agonists reported here. Our findings highlight that nuclear receptor structure and function are dictated by a dynamic conformational equilibrium and that subtle changes in ligand structures can shift this equilibrium in opposite directions, leading to a functional switch from agonists to inverse agonists. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. On conformally related -waves

    Indian Academy of Sciences (India)

    Conformal transformations; conformal Killing vectors; -waves. Abstract. Brinkmann [1] has shown that conformally related distinct Ricci flat solutions are -waves. Brinkmann's result has been generalized to include the conformally invariant source terms. It has been shown that [4] if g i k and g ¯ i k ( = − 2 g i k , : a ...

  13. Rapid muscle activation and force capacity in conditions of chronic musculoskeletal pain

    DEFF Research Database (Denmark)

    Andersen, Lars L; Holtermann, Andreas; Jørgensen, Marie B

    2008-01-01

    muscle activation and force capacity of chronically painful muscles. METHODS: Cross-sectional study with 42 women with chronic trapezius myalgia, and 20 healthy matched controls. Maximal capacity was determined as peak torque and peak EMG amplitude of the painful trapezius and painfree deltoid muscles......-analogue-scale. FINDINGS: Peak torque was 18% lower at 115 degrees shoulder joint angle in women with myalgia compared with healthy controls (Pmuscle (Ptorque development was 33-54% lower (P...BACKGROUND: The association between musculoskeletal pain and decreased maximal muscle strength capacity has been extensively studied, but knowledge about functional rapid force capacity in conditions of chronic musculoskeletal pain is lacking. The objective of this study is to investigate rapid...

  14. Rapid activation of Rac GTPase in living cells by force is independent of Src.

    Directory of Open Access Journals (Sweden)

    Yeh-Chuin Poh

    2009-11-01

    Full Text Available It is well known that mechanical forces are crucial in regulating functions of every tissue and organ in a human body. However, it remains unclear how mechanical forces are transduced into biochemical activities and biological responses at the cellular and molecular level. Using the magnetic twisting cytometry technique, we applied local mechanical stresses to living human airway smooth muscle cells with a magnetic bead bound to the cell surface via transmembrane adhesion molecule integrins. The temporal and spatial activation of Rac, a small guanosine triphosphatase, was quantified using a fluorescent resonance energy transfer (FRET method that measures changes in Rac activity in response to mechanical stresses by quantifying intensity ratios of ECFP (enhanced cyan fluorescent protein as a donor and YPet (a variant yellow fluorescent protein as an acceptor of the Rac biosensor. The applied stress induced rapid activation (less than 300 ms of Rac at the cell periphery. In contrast, platelet derived growth factor (PDGF induced Rac activation at a much later time (>30 sec. There was no stress-induced Rac activation when a mutant form of the Rac biosensor (RacN17 was transfected or when the magnetic bead was coated with transferrin or with poly-L-lysine. It is known that PDGF-induced Rac activation depends on Src activity. Surprisingly, pre-treatment of the cells with specific Src inhibitor PP1 or knocking-out Src gene had no effects on stress-induced Rac activation. In addition, eliminating lipid rafts through extraction of cholesterol from the plasma membrane did not prevent stress-induced Rac activation, suggesting a raft-independent mechanism in governing the Rac activation upon mechanical stimulation. Further evidence indicates that Rac activation by stress depends on the magnitudes of the applied stress and cytoskeletal integrity. Our results suggest that Rac activation by mechanical forces is rapid, direct and does not depend on Src

  15. Retraction: Open and closed conformations reveal induced fit movements in butyrate kinase 2 activation. J. Diao, Y. D. Ma, and M. S. Hasson.

    Science.gov (United States)

    2012-06-01

    The following article from Proteins: Structure, Function, and Bioinformatics, "Open and closed conformations reveal induced fit movements in butyrate kinase 2 activation," by Jiasheng Diao, Yunglin D. Ma, and Miriam S. Hasson, published online on 21 October 2010 in Wiley Online Library (onlinelibrary.wiley.com), has been retracted by agreement between the journal Editor in Chief, Bertrand Garcia-Moreno, and Wiley Periodicals. The retraction has been agreed because it was established by internal investigation performed by Purdue University that the authors of this article are not the owners of the data and have no right to publication. Copyright © 2009 Wiley-Liss, Inc.

  16. Interconversion of active and inactive 30 S ribosomal subunits is accompanied by a conformational change in the decoding region of 16 S rRNA

    DEFF Research Database (Denmark)

    Moazed, D; Van Stolk, B J; Douthwaite, S

    1986-01-01

    Zamir, Elson and their co-workers have shown that 30 S ribosomal subunits are reversibly inactivated by depletion of monovalent or divalent cations. We have re-investigated the conformation of 16 S rRNA in the active and inactive forms of the 30 S subunit, using a strategy that is designed......' regions of 16 S rRNA. The inactive form also shows significantly decreased reactivity at positions 1533 to 1538 (the Shine-Dalgarno region), in agreement with earlier findings. The principal changes in reactivity involve the universally conserved nucleotides G926, C1395, A1398 and G1401. The three purines...

  17. Real-time PCR for rapidly detecting aniline-degrading bacteria in activated sludge.

    Science.gov (United States)

    Kayashima, Takakazu; Suzuki, Hisako; Maeda, Toshinari; Ogawa, Hiroaki I

    2013-05-01

    We developed a detection method that uses quantitative real-time PCR (qPCR) and the TaqMan system to easily and rapidly assess the population of aniline-degrading bacteria in activated sludge prior to conducting a biodegradability test on a chemical compound. A primer and probe set for qPCR was designed by a multiple alignment of conserved amino acid sequences encoding the large (α) subunit of aniline dioxygenase. PCR amplification tests showed that the designed primer and probe set targeted aniline-degrading strains such as Acidovorax sp., Gordonia sp., Rhodococcus sp., and Pseudomonas putida, thereby suggesting that the developed method can detect a wide variety of aniline-degrading bacteria. There was a strong correlation between the relative copy number of the α-aniline dioxygenase gene in activated sludge obtained with the developed qPCR method and the number of aniline-degrading bacteria measured by the Most Probable Number method, which is the conventional method, and a good correlation with the lag time of the BOD curve for aniline degradation produced by the biodegradability test in activated sludge samples collected from eight different wastewater treatment plants in Japan. The developed method will be valuable for the rapid and accurate evaluation of the activity of inocula prior to conducting a ready biodegradability test. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Rapid Shifts in Soil Nutrients and Decomposition Enzyme Activity in Early Succession Following Forest Fire

    Directory of Open Access Journals (Sweden)

    Joseph E. Knelman

    2017-09-01

    Full Text Available While past research has studied forest succession on decadal timescales, ecosystem responses to rapid shifts in nutrient dynamics within the first months to years of succession after fire (e.g., carbon (C burn-off, a pulse in inorganic nitrogen (N, accumulation of organic matter, etc. have been less well documented. This work reveals how rapid shifts in nutrient availability associated with fire disturbance may drive changes in soil enzyme activity on short timescales in forest secondary succession. In this study, we evaluate soil chemistry and decomposition extracellular enzyme activity (EEA across time to determine whether rapid shifts in nutrient availability (1–29 months after fire might control microbial enzyme activity. We found that, with advancing succession, soil nutrients correlate with C-targeting β-1,4-glucosidase (BG EEA four months after the fire, and with N-targeting β-1,4-N-acetylglucosaminidase (NAG EEA at 29 months after the fire, indicating shifting nutrient limitation and decomposition dynamics. We also observed increases in BG:NAG ratios over 29 months in these recently burned soils, suggesting relative increases in microbial activity around C-cycling and C-acquisition. These successional dynamics were unique from seasonal changes we observed in unburned, forested reference soils. Our work demonstrates how EEA may shift even within the first months to years of ecosystem succession alongside common patterns of post-fire nutrient availability. Thus, this work emphasizes that nutrient dynamics in the earliest stages of forest secondary succession are important for understanding rates of C and N cycling and ecosystem development.

  19. Testing the applicability of rapid on-site enzymatic activity detection for surface water monitoring

    Science.gov (United States)

    Stadler, Philipp; Vogl, Wolfgang; Juri, Koschelnik; Markus, Epp; Maximilian, Lackner; Markus, Oismüller; Monika, Kumpan; Peter, Strauss; Regina, Sommer; Gabriela, Ryzinska-Paier; Farnleitner Andreas, H.; Matthias, Zessner

    2015-04-01

    On-site detection of enzymatic activities has been suggested as a rapid surrogate for microbiological pollution monitoring of water resources (e.g. using glucuronidases, galactosidases, esterases). Due to the possible short measuring intervals enzymatic methods have high potential as near-real time water quality monitoring tools. This presentation describes results from a long termed field test. For twelve months, two ColiMinder devices (Vienna Water Monitoring, Austria) for on-site determination of enzymatic activity were tested for stream water monitoring at the experimental catchment HOAL (Hydrological Open Air Laboratory, Center for Water Resource Systems, Vienna University of Technology). The devices were overall able to follow and reflect the diverse hydrological and microbiological conditions of the monitored stream during the test period. Continuous data in high temporal resolution captured the course of enzymatic activity in stream water during diverse rainfall events. The method also proofed sensitive enough to determine diurnal fluctuations of enzymatic activity in stream water during dry periods. The method was able to capture a seasonal trend of enzymatic activity in stream water that matches the results gained from Colilert18 analysis for E. coli and coliform bacteria of monthly grab samples. Furthermore the comparison of ColiMinder data with measurements gained at the same test site with devices using the same method but having different construction design (BACTcontrol, microLAN) showed consistent measuring results. Comparative analysis showed significant differences between measured enzymatic activity (modified fishman units and pmol/min/100ml) and cultivation based analyses (most probable number, colony forming unit). Methods of enzymatic activity measures are capable to detect ideally the enzymatic activity caused by all active target bacteria members, including VBNC (viable but nonculturable) while cultivation based methods cannot detect VBNC

  20. Ligand-dependent conformations and dynamics of the serotonin 5-HT(2A) receptor determine its activation and membrane-driven oligomerization properties.

    Science.gov (United States)

    Shan, Jufang; Khelashvili, George; Mondal, Sayan; Mehler, Ernest L; Weinstein, Harel

    2012-01-01

    From computational simulations of a serotonin 2A receptor (5-HT(2A)R) model complexed with pharmacologically and structurally diverse ligands we identify different conformational states and dynamics adopted by the receptor bound to the full agonist 5-HT, the partial agonist LSD, and the inverse agonist Ketanserin. The results from the unbiased all-atom molecular dynamics (MD) simulations show that the three ligands affect differently the known GPCR activation elements including the toggle switch at W6.48, the changes in the ionic lock between E6.30 and R3.50 of the DRY motif in TM3, and the dynamics of the NPxxY motif in TM7. The computational results uncover a sequence of steps connecting these experimentally-identified elements of GPCR activation. The differences among the properties of the receptor molecule interacting with the ligands correlate with their distinct pharmacological properties. Combining these results with quantitative analysis of membrane deformation obtained with our new method (Mondal et al, Biophysical Journal 2011), we show that distinct conformational rearrangements produced by the three ligands also elicit different responses in the surrounding membrane. The differential reorganization of the receptor environment is reflected in (i)-the involvement of cholesterol in the activation of the 5-HT(2A)R, and (ii)-different extents and patterns of membrane deformations. These findings are discussed in the context of their likely functional consequences and a predicted mechanism of ligand-specific GPCR oligomerization.

  1. Ligand-dependent conformations and dynamics of the serotonin 5-HT(2A receptor determine its activation and membrane-driven oligomerization properties.

    Directory of Open Access Journals (Sweden)

    Jufang Shan

    Full Text Available From computational simulations of a serotonin 2A receptor (5-HT(2AR model complexed with pharmacologically and structurally diverse ligands we identify different conformational states and dynamics adopted by the receptor bound to the full agonist 5-HT, the partial agonist LSD, and the inverse agonist Ketanserin. The results from the unbiased all-atom molecular dynamics (MD simulations show that the three ligands affect differently the known GPCR activation elements including the toggle switch at W6.48, the changes in the ionic lock between E6.30 and R3.50 of the DRY motif in TM3, and the dynamics of the NPxxY motif in TM7. The computational results uncover a sequence of steps connecting these experimentally-identified elements of GPCR activation. The differences among the properties of the receptor molecule interacting with the ligands correlate with their distinct pharmacological properties. Combining these results with quantitative analysis of membrane deformation obtained with our new method (Mondal et al, Biophysical Journal 2011, we show that distinct conformational rearrangements produced by the three ligands also elicit different responses in the surrounding membrane. The differential reorganization of the receptor environment is reflected in (i-the involvement of cholesterol in the activation of the 5-HT(2AR, and (ii-different extents and patterns of membrane deformations. These findings are discussed in the context of their likely functional consequences and a predicted mechanism of ligand-specific GPCR oligomerization.

  2. Activation of raphe nuclei triggers rapid and distinct effects on parallel olfactory bulb output channels.

    Science.gov (United States)

    Kapoor, Vikrant; Provost, Allison C; Agarwal, Prateek; Murthy, Venkatesh N

    2016-02-01

    The serotonergic raphe nuclei are involved in regulating brain states over timescales of minutes and hours. We examined more rapid effects of raphe activation on two classes of principal neurons in the mouse olfactory bulb, mitral and tufted cells, which send olfactory information to distinct targets. Brief stimulation of the raphe nuclei led to excitation of tufted cells at rest and potentiation of their odor responses. While mitral cells at rest were also excited by raphe activation, their odor responses were bidirectionally modulated, leading to improved pattern separation of odors. In vitro whole-cell recordings revealed that specific optogenetic activation of raphe axons affected bulbar neurons through dual release of serotonin and glutamate. Therefore, the raphe nuclei, in addition to their role in neuromodulation of brain states, are also involved in fast, sub-second top-down modulation similar to cortical feedback. This modulation can selectively and differentially sensitize or decorrelate distinct output channels.

  3. Activation of intracellular angiotensin AT2 receptors induces rapid cell death in human uterine leiomyosarcoma cells

    DEFF Research Database (Denmark)

    Zhao, Yi; Lützen, Ulf; Fritsch, Jürgen

    2015-01-01

    of apoptosis and cell death in cultured human uterine leiomyosarcoma (SK-UT-1) cells and control human uterine smooth muscle cells (HutSMC). The intracellular levels of the AT2 receptor are low in proliferating SK-UT-1 cells but the receptor is substantially up-regulated in quiescent SK-UT-1 cells with high...... densities in mitochondria. Activation of the cell membrane AT2 receptors by a concomitant treatment with angiotensin II and the AT1 receptor antagonist, losartan, induces apoptosis but does not affect the rate of cell death. We demonstrate for the first time that the high-affinity, non-peptide AT2 receptor...... agonist, Compound 21 (C21) penetrates the cell membrane of quiescent SK-UT-1 cells, activates intracellular AT2 receptors and induces rapid cell death; approximately 70% of cells died within 24 h. The cells, which escaped from the cell death, displayed activation of the mitochondrial apoptotic pathway, i...

  4. Rapid Cell-Based Assay for Detection and Quantification of Active Staphylococcal Enterotoxin Type D.

    Science.gov (United States)

    Rasooly, Reuven; Do, Paula M; Hernlem, Bradley J

    2017-03-01

    Food poisoning by Staphylococcus aureus is a result of ingestion of Staphylococcal enterotoxins (SEs) produced by this bacterium and is a major source of foodborne illness. Staphylococcal enterotoxin D (SED) is one of the predominant enterotoxins recovered in Staphylococcal food poisoning incidences, including a recent outbreak in Guam affecting 300 children. Current immunology methods for SED detection cannot distinguish between the biologically active form of the toxin, which poses a threat, from the inactive form, which poses no threat. In vivo bioassays that measure emetic activity in kitten and monkeys have been used, but these methods rely upon expensive procedures using live animals and raising ethical concerns. A rapid (5 h) quantitative bioluminescence assay, using a genetically engineered T-cell Jurkat cell line expressing luciferase under regulation of nuclear factor of activated T cells response elements, in combination with the lymphoblastoid B-cell line Raji for antigen presentation, was developed. In this assay, the detection limit of biologically active SED is 100 ng/mL, which is 10 times more sensitive than the splenocyte proliferation assay, and 105 times more sensitive than monkey or kitten bioassay. Pasteurization or repeated freeze-thaw cycles had no effect on SED activity, but reduction in SED activity was shown with heat treatment at 100°C for 5 min. It was also shown that milk exhibits a protective effect on SED. This bioluminescence assay may also be used to rapidly evaluate antibodies to SED for potential therapeutic application as a measurement of neutralizing biological effects of SED. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  5. Rapid NK-cell activation in chicken after infection with infectious bronchitis virus M41.

    Science.gov (United States)

    Vervelde, L; Matthijs, M G R; van Haarlem, D A; de Wit, J J; Jansen, C A

    2013-02-15

    Natural killer (NK) cells are cytotoxic lymphocytes and play an important role in the early defence against viruses. In this study we focussed on NK cell and interferon (IFN) responses after infection with infectious bronchitis virus (IBV). Based on surface expression of CD107+, enhanced activation of lung NK cells was observed at 1 dpi, whereas in blood prolonged NK-cell activation was found. IFN-α and IFN-β mRNA and proteins were not rapidly induced whereas IFN-γ production in lung, measured by Elispot assay, increased over time at 2 and 4 dpi. In contrast, IFN-γ production in blood was highest at 1 dpi and decreased over time down to levels comparable to uninfected birds at 4 dpi. Collectively, infection with IBV-M41 resulted in activation of NK cells in the lung and blood and rapid production of IFN-γ and not IFN-α and IFN-β compared to uninfected birds. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Application of Conformational Space Search in Drug Action | Adikwu ...

    African Journals Online (AJOL)

    The role of conformational space in drug action is presented. Two examples of molecules in different therapeutic groups are presented. Conformational space search will lead to isolating the exact conformation with the desired medicinal properties. Many conformations of a plant isolate may exist which are active, weakly ...

  7. Structure of the complex between trypanosomal triosephosphate isomerase and N-hydroxy-4-phosphono-butanamide: binding at the active site despite an "open" flexible loop conformation.

    Science.gov (United States)

    Verlinde, C L; Witmans, C J; Pijning, T; Kalk, K H; Hol, W G; Callens, M; Opperdoes, F R

    1992-12-01

    The structure of triosephosphate isomerase from Trypanosoma brucei complexed with the competitive inhibitor N-hydroxy-4-phosphono-butanamide was determined by X-ray crystallography to a resolution of 2.84 A. Full occupancy binding of the inhibitor is observed only at one of the active sites of the homodimeric enzyme where the flexible loop is locked in a completely open conformation by crystal contacts. There is evidence that the inhibitor also binds to the second active site of the enzyme, but with low occupancy. The hydroxamyl group of the inhibitor forms hydrogen bonds to the side chains of Asn 11, Lys 13, and His 95, whereas each of its three methylene units is involved in nonpolar interactions with the side chain of the flexible loop residue Ile 172. Interactions between the hydroxamyl and the catalytic base Glu 167 are absent. The binding of this phosphonate inhibitor exhibits three unusual features: (1) the flexible loop is open, in contrast with the binding mode observed in eight other complexes between triosephosphate isomerase and various phosphate and phosphonate compounds; (2) compared with these complexes the present structure reveals a 1.5-A shift of the anion-binding site; (3) this is the first phosphonate inhibitor that is not forced by the enzyme into an eclipsed conformation about the P-CH2 bond. The results are discussed with respect to an ongoing drug design project aimed at the selective inhibition of glycolytic enzymes of T. brucei.

  8. Using rapid assessment and response to operationalise physical activity strategic health communication campaigns in Tonga.

    Science.gov (United States)

    Turk, Tahir; Latu, Netina; Cocker-Palu, Elizabeth; Liavaa, Villiami; Vivili, Paul; Gloede, Sara; Simons, Allison

    2013-04-01

    The aim of the present study was to identify stakeholder and program beneficiary needs and wants in relation to a netball communication strategy in Tonga. In addition, the study aimed to more clearly identify audience segments for targeting of communication campaigns and to identify any barriers or benefits to engaging in the physical activity program. A rapid assessment and response (RAR) methodology was used. The elicitation research encompassed qualitative fieldwork approaches, including semistructured interviews with key informants and focus group discussions with program beneficiaries. Desk research of secondary data sources supported in-field findings. A number of potential barriers to behavioural compliance existed, including cultural factors, gender discrimination, socioeconomic factors, stigmatising attitudes, the threat of domestic violence, infrastructure and training issues. Factors contributing to participation in physical activity included the fun and social aspects of the sport, incentives (including career opportunities, highlighting the health benefits of the activity and the provision of religious and cultural sanctions by local leaders towards the increased physical activity of women. The consultative approach of RAR provided a more in-depth understanding of the need for greater levels of physical activity and opportunities for engagement by all stakeholders. The approach facilitated opportunities for the proposed health behaviours to be realised through the communication strategy. Essential insights for the strategy design were identified from key informants, as well as ensuring future engagement of these stakeholders into the strategy. So what? The expanded use of RAR to inform the design of social marketing interventions is a practical approach to data collection for non-communicable diseases and other health issues in developing countries. The approach allows for the rapid mobilisation of scarce resources for the implementation of more

  9. Development of a New Decision Tree to Rapidly Screen Chemical Estrogenic Activities of Xenopus laevis.

    Science.gov (United States)

    Wang, Ting; Li, Weiying; Zheng, Xiaofeng; Lin, Zhifen; Kong, Deyang

    2014-02-01

    During the last past decades, there is an increasing number of studies about estrogenic activities of the environmental pollutants on amphibians and many determination methods have been proposed. However, these determination methods are time-consuming and expensive, and a rapid and simple method to screen and test the chemicals for estrogenic activities to amphibians is therefore imperative. Herein is proposed a new decision tree formulated not only with physicochemical parameters but also a biological parameter that was successfully used to screen estrogenic activities of the chemicals on amphibians. The biological parameter, CDOCKER interaction energy (Ebinding ) between chemicals and the target proteins was calculated based on the method of molecular docking, and it was used to revise the decision tree formulated by Hong only with physicochemical parameters for screening estrogenic activity of chemicals in rat. According to the correlation between Ebinding of rat and Xenopus laevis, a new decision tree for estrogenic activities in Xenopus laevis is finally proposed. Then it was validated by using the randomly 8 chemicals which can be frequently exposed to Xenopus laevis, and the agreement between the results from the new decision tree and the ones from experiments is generally satisfactory. Consequently, the new decision tree can be used to screen the estrogenic activities of the chemicals, and combinational use of the Ebinding and classical physicochemical parameters can greatly improves Hong's decision tree. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Rapid determination of gross alpha/beta activity in milk using liquid scintilation counter technique

    Directory of Open Access Journals (Sweden)

    Sas Daniel

    2016-01-01

    Full Text Available Rapid determination of gross alpha and beta emitters in milk by liquid scintillation counter is discussed. This method is based on direct addition of different types of milk into scintillation cocktail and therefore it is very promising for fast determination of alpha/beta activity due to direct alpha and beta separation, measurement in close 4p geometry and without sample treatment. The selected group of radionuclides was chosen with the respect to military significance, radio-toxicity, and possibility of potential misuse. As model radionuclides 241Am, 239Pu, and 90Sr were selected. The Liquid Scintilation Counter Hidex 300 SL equipped with triple-double-coincidence-ratio technique was used for sample measurement. The aim of the work was focused on comparison of different cocktails produced by Hidex and Perkin Elmer, choosing the best cocktail based on our measurement results and adjustment of its appropriate volume. Furthermore, the optimization of ratio between the volume of scintillation cocktail and the volume of urine was investigated with the respect to the model radionuclides. According to the obtained results, the efficiency for alpha emitters was greater than 85% and for beta, greater than 95%. The obtained results allowed this method to be used for rapid determination of gross alpha/beta activity in cases where time is an essence, such as first responders or mass-scale samples, where ordinary means suffer from lack of capacity or simply collapse under the onslaught.

  11. Rapid in situ assessment of physiological activities in bacterial biofilms using fluorescent probes

    Science.gov (United States)

    Yu, F. P.; McFeters, G. A.

    1994-01-01

    Two rapid in situ enumeration methods using fluorescent probes were used to assess the physiological activities of Klebsiella pneumoniae biofilms on stainless steel. Fluorescent dyes, 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and rhodamine 123 (Rh 123), were chosen to perform this study. CTC is a soluble redox indicator which can be reduced by respiring bacteria to fluorescent CTC-formazan crystals. Rh 123 is incorporated into bacteria with respect to cellular proton motive force. The intracellular accumulation of these fluorescent dyes can be determined using epifluorescence microscopy. The results obtained with these two fluorescent probes in situ were compared to the plate count (PC) and in situ direct viable count (DVC) methods. Viable cell densities within biofilms determined by the three in situ methods were comparable and always showed approximately 2-fold higher values than those obtained with the PC method. As an additional advantage, the results were observed after 2 h, which was shorter than the 4 h incubation time required for the DVC method and 24 h for colony formation. The results indicate that staining with CTC and Rh 123 provides rapid information regarding cell numbers and physiological activities of bacteria within biofilms.

  12. Rapid regulation of endoplasmic reticulum dynamics in dendritic spines by NMDA receptor activation.

    Science.gov (United States)

    Ng, Ai Na; Doherty, Andrew J; Lombroso, Paul J; Emptage, Nigel J; Collingridge, Graham L

    2014-08-19

    Endoplasmic reticulum (ER) is motile within dendritic spines, but the mechanisms underlying its regulation are poorly understood. To address this issue, we have simultaneously imaged morphology and ER content of dendritic spines in cultured dissociated mouse hippocampal neurons. Over a 10 min period, spines were highly dynamic, with spines both increasing and decreasing in volume. ER was present in approximately 50% of spines and was also highly dynamic, with a net increase over this period of time. Inhibition of the endogenous activation of NMDA receptors resulted in a reduction in ER growth. Conversely, augmentation of the synaptic activation of NMDA receptors, by elimination of striatal-enriched protein tyrosine phosphatase (STEP), resulted in enhanced ER growth. Therefore, NMDA receptors rapidly regulate spine ER dynamics.

  13. Rapid and quantitative measuring of telomerase activity using an electrochemiluminescent sensor

    Science.gov (United States)

    Zhou, Xiaoming; Xing, Da; Zhu, Debin; Jia, Li

    2007-11-01

    Telomerase, a ribonucleoprotein enzyme that adds telomeric repeats to the 3'end of chromosomal DNA for maintaining chromosomal integrity and stability. This strong association of telomerase activity with tumors establishing it is the most widespread cancer marker. A number of assays based on the polymerase chain reaction (PCR) have been developed for the evaluation of telomerase activity. However, those methods require gel electrophoresis and some staining procedures. We developed an electrochemiluminescent (ECL) sensor for the measuring of telomerase activity to overcome these problems such as troublesome post-PCR procedures and semi-quantitative assessment in the conventional method. In this assay 5'-biotinylated telomerase synthesis (TS) primer serve as the substrate for the extension of telomeric repeats under telomerase. The extension products were amplified with this TS primer and a tris-(2'2'-bipyridyl) ruthenium (TBR)-labeled reversed primer. The amplified products was separated and enriched in the surface of electrode by streptavidin-coated magnetic beads, and detected by measuring the ECL signals of the TBR labeled. Measuring telomerase activity use the sensor is easy, sensitive, rapid, and applicable to quantitative analysis, should be clinically useful for the detection and monitoring of telomerase activity.

  14. Dexamethasone rapidly suppresses IL-33-stimulated mast cell function by blocking transcription factor activity.

    Science.gov (United States)

    Paranjape, Anuya; Chernushevich, Oksana; Qayum, Amina Abdul; Spence, Andrew J; Taruselli, Marcela T; Abebayehu, Daniel; Barnstein, Brian O; McLeod, Jamie Josephine Avila; Baker, Bianca; Bajaj, Gurjas S; Chumanevich, Alena P; Oskeritzian, Carole A; Ryan, John J

    2016-12-01

    Mast cells are critical effectors of allergic disease and can be activated by IL-33, a proinflammatory member of the IL-1 cytokine family. IL-33 worsens the pathology of mast cell-mediated diseases, but therapies to antagonize IL-33 are still forthcoming. Because steroids are the mainstay of allergic disease treatment and are well known to suppress mast cell activation by other stimuli, we examined the effects of the steroid dexamethasone on IL-33-mediated mast cell function. We found that dexamethasone potently and rapidly suppressed cytokine production elicited by IL-33 from murine bone marrow-derived and peritoneal mast cells. IL-33 enhances IgE-mediated mast cell cytokine production, an activity that was also antagonized by dexamethasone. These effects were consistent in human mast cells. We additionally observed that IL-33 augmented migration of IgE-sensitized mast cells toward antigen. This enhancing effect was similarly reversed by dexamethasone. Simultaneous addition of dexamethasone with IL-33 had no effect on the phosphorylation of MAP kinases or NFκB p65 subunit; however, dexamethasone antagonized AP-1- and NFκB-mediated transcriptional activity. Intraperitoneal administration of dexamethasone completely abrogated IL-33-mediated peritoneal neutrophil recruitment and prevented plasma IL-6 elevation. These data demonstrate that steroid therapy may be an effective means of antagonizing the effects of IL-33 on mast cells in vitro and in vivo, acting partly by suppressing IL-33-induced NFκB and AP-1 activity. © Society for Leukocyte Biology.

  15. Relationship between structure, conformational flexibility, and biological activity of agonists and antagonists at the N-methyl-D-aspartic acid subtype of excitatory amino acid receptors

    DEFF Research Database (Denmark)

    Madsen, U; Brehm, L; Schaumburg, Kjeld

    1990-01-01

    spectroscopy and supported by computer simulations and molecular mechanics calculations. While the trans forms of 2,3-PDA and 2,4-PDA and cis-2,5-PDA show NMDA receptor agonist activities, cis-2,3-PDA and cis-2,4-PDA are NMDA antagonists. The compounds trans-2,5-PDA and cis-2,6-PDA did not interact with NMDA...... receptors. Each of the three cyclic acidic amino acids showing NMDA agonist activities was found to exist as an equilibrium mixture of two conformers in aqueous solution. In contrast, the NMDA antagonists cis-2,3-PDA and cis-2,4-PDA as well as the inactive compounds trans-2,5-PDA and cis-2,6-PDA were shown...

  16. Conformational modulation of in vitro activity of cyclic RGD peptides via aziridine aldehyde-driven macrocyclization chemistry.

    Science.gov (United States)

    Roxin, Áron; Chen, Juan; Scully, Conor C G; Rotstein, Benjamin H; Yudin, Andrei K; Zheng, Gang

    2012-07-18

    Here, we demonstrate a conjugation strategy whereby cyclic RGD-containing macrocycles are prepared using aziridine aldehydes, isocyanides, and linear peptides, followed by conjugation to a cysteamine linker. Our method involves site-selective aziridine ring-opening with the nucleophilic sulfhydryl group of cysteamine. Fluorescein was then efficiently conjugated to the primary amine of cysteamine by NHS-chemistry. This strategy may be expanded to provide easy access to a wide variety of fluorescent dyes or radiometal chelators. Modeling studies showed that aziridine aldehyde cyclization chemistry stabilized the RGD motif into the required bioactive conformation and that this cyclization chemistry modulated the geometry of macrocycles of different residue lengths. In vitro studies showed that cPRGDA and cPRGDAA both selectively bound to α(V)β(3)-overexpressing U87 glioblastoma cells, and that cPRGDA had a better binding affinity compared to cPRGDAA. The improved binding affinity of cPRGDA was attributed to the fixed Pro-C(α)-Asp-C(α) distance surrounding the stabilized RGD motif in cPRGDA.

  17. Structure and cytotoxic activity of sesquiterpene glycoside esters from Calendula officinalis L.: Studies on the conformation of viridiflorol.

    Science.gov (United States)

    D'Ambrosio, Michele; Ciocarlan, Alexandru; Colombo, Elisa; Guerriero, Antonio; Pizza, Cosimo; Sangiovanni, Enrico; Dell'Agli, Mario

    2015-09-01

    Topic applications of Calendula officinalis L. lipophilic extracts are used in phytotherapy to relieve skin inflammatory conditions whereas infusions are used as a remedy for gastric complaints. Such a different usage might be explained by some cytotoxicity of lipophilic extracts at gastric level but little is known about this. Therefore, we screened the CH2Cl2 extract from the flowers of C. officinalis by MTT and LDH assays in human epithelial gastric cells AGS. This bioassay-oriented approach led to the isolation of several sesquiterpene glycosides which were structurally characterized by spectroscopic measurements, chemical reactions and MM calculations. The conformational preferences of viridiflorol fucoside were established and a previously assigned stereochemistry was revised. The compounds 1a, 2a and 3f showed comparably high cytotoxicity in the MTT assays, whereas the effect on LDH release was lower. Our study provides new insights on the composition of C. officinalis extracts of medium polarity and identifies the main compounds that could be responsible for cytotoxic effects at gastric level. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Applications of hydrogen deuterium exchange (HDX for the characterization of conformational dynamics in light-activated photoreceptors

    Directory of Open Access Journals (Sweden)

    Robert eLindner

    2015-06-01

    Full Text Available Rational design of optogenetic tools is inherently linked to the understanding of photoreceptor function. Structural analysis of elements involved in signal integration in individual sensor domains provides an initial idea of their mode of operation, but understanding how local structural rearrangements eventually affect signal transmission to output domains requires inclusion of the effector regions in the characterization. However, the dynamic nature of these assemblies renders their structural analysis challenging and therefore a combination of high- and low-resolution techniques is required to appreciate functional aspects of photoreceptors.This review focuses on the potential of Hydrogen-Deuterium exchange coupled to mass spectrometry (HDX-MS for complementing the structural characterization of photoreceptors. In this respect, the ability of HDX-MS to provide information on the conformational dynamics and the possibility to address multiple functionally relevant states in solution render this methodology ideally suitable. We highlight recent examples demonstrating the potential of HDX-MS and discuss how these results can help to improve existing optogenetic systems or guide the design of novel optogenetic tools.

  19. Rapid estimation of activation enthalpies for cytochrome-P450-mediated hydroxylations.

    Science.gov (United States)

    Mayeno, Arthur N; Robinson, Jonathan L; Reisfeld, Brad

    2011-03-01

    Cytochrome P450 (CYP) enzymes play a critical role in detoxication and bioactivation of xenobiotics; thus, the ability to predict the biotransformation rates and regioselectivity of CYP enzymes toward substrates is an important goal in toxicology and pharmacology. Here, we present the use of the semiempirical quantum chemistry method SAM1 to rapidly estimate relative activation enthalpies (ΔH(‡)) for the hydroxylation of aliphatic carbon centers of various substrates. The ΔH(‡) were determined via a reaction path calculation, in the reverse direction (RRP), using the iron-hydroxo-porphine intermediate and the substrate radical. The SAM1 ΔH(‡) were calculated via unrestricted Hartree-Fock (UHF) and configuration interaction (CI) formalisms for both the doublet and quartet spin states. The SAM1 RRP ΔH(‡), after subtracting a correction factor, were compared with density functional theory (DFT) B3LYP activation energies for two sets of substrates and showed R(2) ranging from 0.69 to 0.89, and mean absolute differences ranging from 1.2 ± 1.0 to 1.7 ± 1.5 kcal/mol. SAM1 UHF and CI RRP calculation times were, on average, more than 200 times faster than those for the corresponding forward reaction path DFT calculations. Certain key transition-state (TS) geometry measurements, such as the forming O···H bond length, showed good correlation with the DFT values. These results suggest that the SAM1 RRP approach can be used to rapidly estimate the DFT activation energy and some key TS geometry measurements and can potentially be applied to estimate substrate hydroxylation rates and regioselectivity by CYP enzymes. Copyright © 2010 Wiley Periodicals, Inc.

  20. Viscous conformal gauge theories

    DEFF Research Database (Denmark)

    Toniato, Arianna; Sannino, Francesco; Rischke, Dirk H.

    2017-01-01

    We present the conformal behavior of the shear viscosity-to-entropy density ratio and the fermion-number diffusion coefficient within the perturbative regime of the conformal window for gauge-fermion theories.......We present the conformal behavior of the shear viscosity-to-entropy density ratio and the fermion-number diffusion coefficient within the perturbative regime of the conformal window for gauge-fermion theories....

  1. CE: Original research: hospital system barriers to rapid response team activation: a cognitive work analysis.

    Science.gov (United States)

    Braaten, Jane Saucedo

    2015-02-01

    The goal of rapid response team (RRT) activation in acute care facilities is to decrease mortality from preventable complications, but such efforts have been only moderately successful. Although recent research has shown decreased mortality when RRTs are activated more often, many hospitals have low activation rates. This has been linked to various hospital, team, and nursing factors. Yet there is a dearth of research examining how hospital systems shape nurses' behavior with regard to RRT activation. Making systemic constraints visible and modifying them may be the key to improving RRT activation rates and saving more lives. The purpose of this study was to use cognitive work analysis to describe factors within the hospital system that shape medical-surgical nurses' RRT activation behavior. Cognitive work analysis offers a framework for the study of complex sociotechnical systems. This framework was used as the organizing element of the study. Qualitative descriptive design was used to obtain data to fill the framework's five domains: resources, tasks, strategies, social systems, and worker competency. Data were obtained from interviews with 12 medical-surgical nurses and document review. Directed content analysis was used to place the obtained data into the framework's predefined domains. Many system factors affected participants' decisions to activate or not activate an RRT. Systemic constraints, especially in cases of subtle or gradual clinical changes, included a lack of adequate information, the availability of multiple strategies, the need to justify RRT activation, a scarcity of human resources, and informal hierarchical norms in the hospital culture. The most profound constraint was the need to justify the call. Justification was based on the objective or subjective nature of clinical changes, whether the nurse expected to be able to "handle" these changes, the presence or absence of a physician, and whether there was an expectation of support from the RRT

  2. Superspace conformal field theory

    Energy Technology Data Exchange (ETDEWEB)

    Quella, Thomas [Koeln Univ. (Germany). Inst. fuer Theoretische Physik; Schomerus, Volker [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-07-15

    Conformal sigma models and WZW models on coset superspaces provide important examples of logarithmic conformal field theories. They possess many applications to problems in string and condensed matter theory. We review recent results and developments, including the general construction of WZW models on type I supergroups, the classification of conformal sigma models and their embedding into string theory.

  3. [Antimicrobial and rapid bactericidal activities of sitafloxacin and other agents against Streptococcus pyogenes].

    Science.gov (United States)

    Namba, Eiko; Okumura, Ryo; Chiba, Megumi; Hoshino, Kazuki; Tateda, Kazuhiro

    2013-10-01

    We evaluated the in vitro activity of sitafloxacin against Japanese clinical isolates of Streptococcus pyogenes by broth microdilution susceptibility testing and time-kill studies to elucidate its eradication potential against S. pyogenes. One hundred and nineteen clinical isolates of S. pyogenes isolated from pharynx were tested to sitafloxacin and seven other agents in the susceptibility testing. The time-kill studies were conducted with five strains, one of which was resistant to clarithromycin, one resistant to levofloxacin and one type strain of S. pyogenes. In the time-kill studies, sitafloxacin, garenoxacin, amoxicillin and clarithromycin were assessed at static concentrations of their respective peak concentrations in plasma (C(max)) when administered as oral single doses for adult patients with S. pyogenes infections. We found the rank order of antimicrobial activity against S. pyogenes isolates was: cefcapene (MIC90, 0.015 microg/mL) > amoxicillin (0.03 microg/mL) > sitafloxacin (0.12 microg/mL) > garenoxacin (0.25 microg/mL) > levofloxacin (4 microg/mL) > minocycline (16 microg/mL). Macrolide-resistant isolates accounted for 72 (60.5%), resulting in clarithromycin and azithromycin MIC90s of > 32 and > 128 microg/mL, respectively. Sitafloxacin exhibited the most rapid bactericidal activity (> or = log reduction from the initial inoculum) within 2h against all tested strains, including even one levofloxacin-resistant strain. For garenoxacin, bactericidal activity was achieved between 2 and 6 h. Amoxicillin revealed no significant bactericidal activity up to 6 h. Clarithromycin showed no bactericidal activity and did not inhibit growth of a clarithromycin-resistant strain. These data indicate the potential usefulness of sitafloxacin for the treatment of S. pyogenes eradication.

  4. Communication and general concern criterion prior to activation of the rapid response team: a grounded theory.

    Science.gov (United States)

    Martland, Jarrad; Chamberlain, Diane; Hutton, Alison; Smigielski, Michael

    2016-11-01

    Objective Patients commonly show signs and symptoms of deterioration for hours or days before cardiorespiratory arrest. Rapid response teams (RRT) were created to improve recognition and response to patient deterioration in these situations. Activation criteria include vital signs or 'general concern' by a clinician or family member. The general concern criterion for RRT activation accounts for nearly one-third of all RRT activity, and although it is well established that communication deficits between staff can contribute to poorer outcomes for patients, there is little evidence pertaining to communication and its effects on the general concern RRT activation. Thus, the aim of the present study was to develop a substantive grounded theory related to the communication process between clinicians that preceded the activation of an RRT when general concern criterion was used. Methods Qualitative grounded theory involved collection of three types of data details namely personal notes from participants in focus groups with white board notes from discussions and audio recordings of the focus groups sessions. Focus groups were conducted with participants exploring issues associated with clinician communication and how it related to the activation of an RRT using the general concern criterion. Results The three main phases of coding (i.e. open, axial and selective coding) analysis identified 322 separate open codes. The strongest theme contributed to a theory of ineffective communication and decreased psychological safety, namely that 'In the absence of effective communication there is a subsequent increase in anxiety, fear or concern that can be directly attributed to the activation of an RRT using the 'general concern' criterion'. The RRT filled cultural and process deficiencies in the compliance with an escalation protocol. Issues such as 'not for resuscitation documentation' and 'inability to establish communication with and between medical or nursing personnel' rated

  5. Three dimensional evaluation of alveolar bone changes in response to different rapid palatal expansion activation rates

    Directory of Open Access Journals (Sweden)

    Brian LaBlonde

    Full Text Available ABSTRACT Introduction: The aim of this multi-center retrospective study was to quantify the changes in alveolar bone height and thickness after using two different rapid palatal expansion (RPE activation protocols, and to determine whether a more rapid rate of expansion is likely to cause more adverse effects, such as alveolar tipping, dental tipping, fenestration and dehiscence of anchorage teeth. Methods: The sample consisted of pre- and post-expansion records from 40 subjects (age 8-15 years who underwent RPE using a 4-banded Hyrax appliance as part of their orthodontic treatment to correct posterior buccal crossbites. Subjects were divided into two groups according to their RPE activation rates (0.5 mm/day and 0.8 mm/day; n = 20 each group. Three-dimensional images for all included subjects were evaluated using Dolphin Imaging Software 11.7 Premium. Maxillary base width, buccal and palatal cortical bone thickness, alveolar bone height, and root angulation and length were measured. Significance of the changes in the measurements was evaluated using Wilcoxon signed-rank test and comparisons between groups were done using ANOVA. Significance was defined at p ≤ 0.05. Results: RPE activation rates of 0.5 mm per day (Group 1 and 0.8 mm per day (Group 2 caused significant increase in arch width following treatment; however, Group 2 showed greater increases compared to Group 1 (p < 0.01. Buccal alveolar height and width decreased significantly in both groups. Both treatment protocols resulted in significant increases in buccal-lingual angulation of teeth; however, Group 2 showed greater increases compared to Group 1 (p < 0.01. Conclusion: Both activation rates are associated with significant increase in intra-arch widths. However, 0.8 mm/day resulted in greater increases. The 0.8 mm/day activation rate also resulted in more increased dental tipping and decreased buccal alveolar bone thickness over 0.5 mm/day.

  6. Internal Porosity of Mineral Coating Supports Microbial Activity in Rapid Sand Filters for Groundwater Treatment

    DEFF Research Database (Denmark)

    Gülay, Arda; Tatari, Karolina; Musovic, Sanin

    2014-01-01

    prokaryotes in filter material with various degrees of mineral coating. We also examined the physical and chemical characteristics of the mineral coating. The amount of mineral coating correlated positively with the internal porosity, the packed bulk density, and the biologically available surface area.......6 μm) of the mineral coating, which had a thickness of up to 600 ± 51 μm. Environmental scanning electron microscopic (E-SEM) observations suggested an extracellular polymeric substance-rich matrix and submicron-sized bacterial cells. Nitrifier diversity profiles were similar irrespective of the degree...... of mineral coating, as indicated by pyrosequencing analysis. Overall, our results demonstrate that mineral coating positively affects microbial colonization and activity in rapid sand filters, most likely due to increased volumetric cell abundances facilitated by the large surface area of internal mineral...

  7. ER Stress Causes Rapid Loss of Intestinal Epithelial Stemness through Activation of the Unfolded Protein Response

    Directory of Open Access Journals (Sweden)

    Jarom Heijmans

    2013-04-01

    Full Text Available Stem cells generate rapidly dividing transit-amplifying cells that have lost the capacity for self-renewal but cycle for a number of times until they exit the cell cycle and undergo terminal differentiation. We know very little of the type of signals that trigger the earliest steps of stem cell differentiation and mediate a stem cell to transit-amplifying cell transition. We show that in normal intestinal epithelium, endoplasmic reticulum (ER stress and activity of the unfolded protein response (UPR are induced at the transition from stem cell to transit-amplifying cell. Induction of ER stress causes loss of stemness in a Perk-eIF2α-dependent manner. Inhibition of Perk-eIF2α signaling results in stem cell accumulation in organoid culture of primary intestinal epithelium. Our findings show that the UPR plays an important role in the regulation of intestinal epithelial stem cell differentiation.

  8. A Rapid and Sensitive Method to Measure the Functional Activity of Shiga Toxins in Human Serum

    Directory of Open Access Journals (Sweden)

    Valentina Arfilli

    2015-11-01

    Full Text Available Shiga toxins (Stx have a definite role in the development of hemolytic uremic syndrome in children with hemorrhagic colitis caused by pathogenic Stx-producing Escherichia coli (STEC strains. The dramatic effects of these toxins on the microvasculature of different organs, particularly of the kidney, are well known, whereas there is no consensus on the mechanism by which Stx reach the endothelia of target organs and/or indirectly injure these body sites. We hereby describe a quick (4 h, radioactive, Raji cell-based method designed for the detection of Stx in human sera. The assay monitors the translation impairment induced by these powerful inhibitors of protein synthesis, which are identified properly by neutralizing their activity with specific monoclonal antibodies. By this method, we detected for the first time the functional activity of Stx in sera of STEC-infected patients during hemorrhagic colitis. Recent research has pointed to a dynamic process of Stx-induced renal intoxication in which concurrent and interactive steps are involved. Our rapid and specific method could be useful for studying the kinetics of Stx during the natural course of STEC infection and the interplay between Stx activity in serum and Stx presence in different blood fractions (neutrophils, monocytes, platelets, leukocyte-platelet aggregates, microvesicles, lipoproteins.

  9. A Rapid and Sensitive Method to Measure the Functional Activity of Shiga Toxins in Human Serum

    Science.gov (United States)

    Arfilli, Valentina; Carnicelli, Domenica; Ardissino, Gianluigi; Torresani, Erminio; Scavia, Gaia; Brigotti, Maurizio

    2015-01-01

    Shiga toxins (Stx) have a definite role in the development of hemolytic uremic syndrome in children with hemorrhagic colitis caused by pathogenic Stx-producing Escherichia coli (STEC) strains. The dramatic effects of these toxins on the microvasculature of different organs, particularly of the kidney, are well known, whereas there is no consensus on the mechanism by which Stx reach the endothelia of target organs and/or indirectly injure these body sites. We hereby describe a quick (4 h), radioactive, Raji cell-based method designed for the detection of Stx in human sera. The assay monitors the translation impairment induced by these powerful inhibitors of protein synthesis, which are identified properly by neutralizing their activity with specific monoclonal antibodies. By this method, we detected for the first time the functional activity of Stx in sera of STEC-infected patients during hemorrhagic colitis. Recent research has pointed to a dynamic process of Stx-induced renal intoxication in which concurrent and interactive steps are involved. Our rapid and specific method could be useful for studying the kinetics of Stx during the natural course of STEC infection and the interplay between Stx activity in serum and Stx presence in different blood fractions (neutrophils, monocytes, platelets, leukocyte-platelet aggregates, microvesicles, lipoproteins). PMID:26556372

  10. Colorimetry and SERS dual-mode detection of telomerase activity: combining rapid screening with high sensitivity.

    Science.gov (United States)

    Zong, Shenfei; Wang, Zhuyuan; Chen, Hui; Hu, Guohua; Liu, Min; Chen, Peng; Cui, Yiping

    2014-01-01

    As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and surface enhanced Raman scattering (SERS) dual-mode telomerase activity detection method, which has several distinctive advantages. First, colorimetric functionality allows rapid preliminary discrimination of telomerase activity by the naked eye. Second, the employment of SERS technique results in greatly improved detection sensitivity. Third, the combination of colorimetry and SERS into one detection system can ensure highly efficacious and sensitive screening of numerous samples. Besides, the avoidance of polymerase chain reaction (PCR) procedures further guarantees fine reliability and simplicity. Generally, the presented method is realized by an "elongate and capture" procedure. To be specific, gold nanoparticles modified with Raman molecules and telomeric repeat complementary oligonucleotide are employed as the colorimetric-SERS bifunctional reporting nanotag, while magnetic nanoparticles functionalized with telomerase substrate oligonucleotide are used as the capturing substrate. Telomerase can synthesize and elongate telomeric repeats onto the capturing substrate. The elongated telomeric repeats subsequently facilitate capturing of the reporting nanotag via hybridization between telomeric repeat and its complementary strand. The captured nanotags can cause a significant difference in the color and SERS intensity of the magnetically separated sediments. Thus both the color and SERS can be used as indicators of the telomerase activity. With fast screening ability and outstanding sensitivity, we anticipate that this method would greatly promote practical application of telomerase-based early-stage cancer diagnosis.

  11. Epigenetic dominance of prion conformers.

    Directory of Open Access Journals (Sweden)

    Eri Saijo

    2013-10-01

    Full Text Available Although they share certain biological properties with nucleic acid based infectious agents, prions, the causative agents of invariably fatal, transmissible neurodegenerative disorders such as bovine spongiform encephalopathy, sheep scrapie, and human Creutzfeldt Jakob disease, propagate by conformational templating of host encoded proteins. Once thought to be unique to these diseases, this mechanism is now recognized as a ubiquitous means of information transfer in biological systems, including other protein misfolding disorders such as those causing Alzheimer's and Parkinson's diseases. To address the poorly understood mechanism by which host prion protein (PrP primary structures interact with distinct prion conformations to influence pathogenesis, we produced transgenic (Tg mice expressing different sheep scrapie susceptibility alleles, varying only at a single amino acid at PrP residue 136. Tg mice expressing ovine PrP with alanine (A at (OvPrP-A136 infected with SSBP/1 scrapie prions propagated a relatively stable (S prion conformation, which accumulated as punctate aggregates in the brain, and produced prolonged incubation times. In contrast, Tg mice expressing OvPrP with valine (V at 136 (OvPrP-V136 infected with the same prions developed disease rapidly, and the converted prion was comprised of an unstable (U, diffusely distributed conformer. Infected Tg mice co-expressing both alleles manifested properties consistent with the U conformer, suggesting a dominant effect resulting from exclusive conversion of OvPrP-V136 but not OvPrP-A136. Surprisingly, however, studies with monoclonal antibody (mAb PRC5, which discriminates OvPrP-A136 from OvPrP-V136, revealed substantial conversion of OvPrP-A136. Moreover, the resulting OvPrP-A136 prion acquired the characteristics of the U conformer. These results, substantiated by in vitro analyses, indicated that co-expression of OvPrP-V136 altered the conversion potential of OvPrP-A136 from the S to

  12. Thermal Behaviour, Biological Activity and Conformational Study of a [Methoprene/β-Cyclodextrin] Complex in a Smoke Generating Formulation

    Directory of Open Access Journals (Sweden)

    Eduardo Zerba

    2005-05-01

    Full Text Available Methoprene, an insect growth regulator, was complexed with β-cyclodextrin, yielding a stable inclusion complex. TGA, X-ray powder diffraction and conformational analysis have been used to confirm the nature of this inclusion complex. The interaction between methoprene and β-cyclodextrin was investigated by means of Molecular Mechanics. The results account for the formation of a 1:1 inclusion complex stabilised by Van der Waals forces and hydrogen bonds. The [methoprene–β-cyclodextrin] complex included in smoke generating formulations and protected from thermal decomposition by the foaming agent azodicarbonamide was shown to be stable enough to release methoprene in fumes with good yields. The improved stabilty of the methoprene complex showed a correlation with increased biological activity against Musca domestica.

  13. Reinforcement learning signal predicts social conformity.

    Science.gov (United States)

    Klucharev, Vasily; Hytönen, Kaisa; Rijpkema, Mark; Smidts, Ale; Fernández, Guillén

    2009-01-15

    We often change our decisions and judgments to conform with normative group behavior. However, the neural mechanisms of social conformity remain unclear. Here we show, using functional magnetic resonance imaging, that conformity is based on mechanisms that comply with principles of reinforcement learning. We found that individual judgments of facial attractiveness are adjusted in line with group opinion. Conflict with group opinion triggered a neuronal response in the rostral cingulate zone and the ventral striatum similar to the "prediction error" signal suggested by neuroscientific models of reinforcement learning. The amplitude of the conflict-related signal predicted subsequent conforming behavioral adjustments. Furthermore, the individual amplitude of the conflict-related signal in the ventral striatum correlated with differences in conforming behavior across subjects. These findings provide evidence that social group norms evoke conformity via learning mechanisms reflected in the activity of the rostral cingulate zone and ventral striatum.

  14. Rapid activation of inwardly rectifying potassium channels by immobile G-protein-coupled receptors.

    Science.gov (United States)

    Lober, Robert M; Pereira, Miguel A; Lambert, Nevin A

    2006-11-29

    G-protein-coupled receptors (GPCRs) mediate slow synaptic transmission and many other effects of small molecule and peptide neurotransmitters. In the standard model of GPCR signaling, receptors and G-proteins diffuse laterally within the plane of the plasma membrane and encounter each other by random collision. This model predicts that signaling will be most efficient if both GPCRs and G-proteins are free to diffuse, thus maximizing collision frequency. However, neuronal GPCRs are often recruited to and enriched at specific synaptic locations, suggesting receptor mobility is restricted in these cells. Here, we test the hypothesis that restricting GPCR mobility impairs signaling in neurons by limiting the frequency of collisions between receptors and G-proteins. Mu-opioid receptors (MORs) were immobilized on the surface of cerebellar granule neurons by avidin-mediated cross-linking, and inwardly rectifying potassium (GIRK) channels were used as rapid indicators of G-protein activation. Mobile and immobile MORs activated GIRK channels with the same onset kinetics and agonist sensitivity in these neurons. In a heterologous expression system, GFP (green fluorescent protein)-tagged G alpha(oA) subunits remained mobile after cross-linking, but their mobility was reduced in the presence of immobile MORs, suggesting that these receptors and subunits were transiently precoupled. In addition, channel activation could be reconstituted with immobile GPCRs, G-protein heterotrimers, and GIRK channels. These results show that collision frequency is not rate-limiting for G-protein activation in CNS neurons, and are consistent with the idea that signaling components are compartmentalized or preassembled.

  15. Activation of Notch3 in Glomeruli Promotes the Development of Rapidly Progressive Renal Disease.

    Science.gov (United States)

    El Machhour, Fala; Keuylian, Zela; Kavvadas, Panagiotis; Dussaule, Jean-Claude; Chatziantoniou, Christos

    2015-07-01

    Notch3 expression is found in the glomerular podocytes of patients with lupus nephritis or focal segmental GN but not in normal kidneys. Here, we show that activation of the Notch3 receptor in the glomeruli is a turning point inducing phenotypic changes in podocytes promoting renal inflammation and fibrosis and leading to disease progression. In a model of rapidly progressive GN, Notch3 expression was induced by several-fold in podocytes concurrently with disease progression. By contrast, mice lacking Notch3 expression were protected because they exhibited less proteinuria, uremia, and inflammatory infiltration. Podocyte outgrowth from glomeruli isolated from wild-type mice during the early phase of the disease was higher than outgrowth from glomeruli of mice lacking Notch3. In vitro studies confirmed that podocytes expressing active Notch3 reorganize their cytoskeleton toward a proliferative/migratory and inflammatory phenotype. We then administered antisense oligodeoxynucleotides targeting Notch3 or scramble control oligodeoxynucleotides in wild-type mice concomitant to disease induction. Both groups developed chronic renal disease, but mice injected with Notch3 antisense had lower values of plasma urea and proteinuria and inflammatory infiltration. The improvement of renal function was accompanied by fewer deposits of fibrin within the glomeruli and by decreased peritubular inflammation. Finally, abnormal Notch3 staining was observed in biopsy samples of patients with crescentic GN. These results demonstrate that abnormal activation of Notch3 may be involved in the progression of renal disease by promoting migratory and proinflammatory pathways. Inhibiting Notch3 activation could be a novel, promising approach to treat GN. Copyright © 2015 by the American Society of Nephrology.

  16. ATP and MO25? Regulate the Conformational State of the STRAD? Pseudokinase and Activation of the LKB1 Tumour Suppressor

    OpenAIRE

    Zeqiraj, Elton; Filippi, Beatrice Maria; Goldie, Simon; Navratilova, Iva; Boudeau, J?r?me; Deak, Maria; Alessi, Dario R.; van Aalten, Daan M. F.

    2009-01-01

    Pseudokinases lack essential residues for kinase activity, yet are emerging as important regulators of signal transduction networks. The pseudokinase STRAD activates the LKB1 tumour suppressor by forming a heterotrimeric complex with LKB1 and the scaffolding protein MO25. Here, we describe the structure of STRADalpha in complex with MO25alpha. The structure reveals an intricate web of interactions between STRADalpha and MO25alpha involving the alphaC-helix of STRADalpha, reminiscent of the me...

  17. Conformation of hindered piperidines: Spectroscopic evidence for ...

    Indian Academy of Sciences (India)

    Administrator

    C NMR; conformational analysis; boat forms. 1. Introduction. Many piperidine derivatives are found to possess pharmacological activity and form an essential part of the molecular structure of important drugs. 1. Most of the piperidine precursors are known to exist in chair conformation. Electron withdrawing groups. (–NO ...

  18. Rapid Detection of Microorganisms Based on Active and Passive Modes of QCM

    Directory of Open Access Journals (Sweden)

    Zdeněk Farka

    2014-12-01

    Full Text Available Label-free immunosensors are well suited for detection of microorganisms because of their fast response and reasonable sensitivity comparable to infection doses of common pathogens. Active (lever oscillator and frequency counter and passive (impedance analyzer modes of quartz crystal microbalance (QCM were used and compared for rapid detection of three strains of E. coli. Different approaches for antibody immobilization were compared, the immobilization of reduced antibody using Sulfo‑SMCC was most effective achieving the limit of detection (LOD 8 × 104 CFU·mL−1 in 10 min. For the passive mode, software evaluating impedance characteristics in real-time was developed and used. Almost the same results were achieved using both active and passive modes confirming that the sensor properties are not limited by the frequency evaluation method but mainly by affinity of the antibody. Furthermore, reference measurements were done using surface plasmon resonance. Effect of condition of cells on signal was observed showing that cells ruptured by ultrasonication provided slightly higher signal changes than intact microbes.

  19. Activated Carbon Fibers "Thickly Overgrown" by Ag Nanohair Through Self-Assembly and Rapid Thermal Annealing

    Science.gov (United States)

    Yan, Xuefeng; Xu, Sijun; Wang, Qiang; Fan, Xuerong

    2017-11-01

    Anisotropic nanomaterial-modified carbon fibers attract increasing attention because of their superior properties over traditional ones. In this study, activated carbon fibers (ACFs) "thickly overgrown" by Ag nanohair were prepared through self-assembly and rapid thermal annealing. Viscose fibers with well-dispersed silver nanoparticles (AgNPs) on surfaces were first prepared through self-assembly of hyperbranched poly(amino-amine) (HBPAA)-capped AgNPs on viscose surfaces. HBPAA endowed the AgNP surfaces with negative charges and abundant amino groups, allowing AgNPs to monodispersively self-assemble to fiber surfaces. Ag nanohair-grown ACFs were prepared by sequential pre-oxidation and carbonization. Because the carbonization furnace was open-ended, ACFs are immediately transferrable to the outside of the furnace. Therefore, the Ag liquid adsorbed by ACF pores squeezed out to form Ag nanowires through thermal contraction. FESEM characterization indicated that Ag nanohairs stood on ACF surface and grew from ACF caps. XPS and XRD characterization showed that Ag successfully assembled to fiber surfaces and retained its metallic state even after high-temperature carbonization. TG analysis suggested that Ag nanohair-grown ACFs maintained their excellent thermal stabilities. Finally, the fabricated ACFs showed excellent and durable antibacterial activities, and the developed method may provide a potential strategy for preparing metal nanowire-grown ACFs.

  20. Activated Carbon Fibers "Thickly Overgrown" by Ag Nanohair Through Self-Assembly and Rapid Thermal Annealing.

    Science.gov (United States)

    Yan, Xuefeng; Xu, Sijun; Wang, Qiang; Fan, Xuerong

    2017-11-09

    Anisotropic nanomaterial-modified carbon fibers attract increasing attention because of their superior properties over traditional ones. In this study, activated carbon fibers (ACFs) "thickly overgrown" by Ag nanohair were prepared through self-assembly and rapid thermal annealing. Viscose fibers with well-dispersed silver nanoparticles (AgNPs) on surfaces were first prepared through self-assembly of hyperbranched poly(amino-amine) (HBPAA)-capped AgNPs on viscose surfaces. HBPAA endowed the AgNP surfaces with negative charges and abundant amino groups, allowing AgNPs to monodispersively self-assemble to fiber surfaces. Ag nanohair-grown ACFs were prepared by sequential pre-oxidation and carbonization. Because the carbonization furnace was open-ended, ACFs are immediately transferrable to the outside of the furnace. Therefore, the Ag liquid adsorbed by ACF pores squeezed out to form Ag nanowires through thermal contraction. FESEM characterization indicated that Ag nanohairs stood on ACF surface and grew from ACF caps. XPS and XRD characterization showed that Ag successfully assembled to fiber surfaces and retained its metallic state even after high-temperature carbonization. TG analysis suggested that Ag nanohair-grown ACFs maintained their excellent thermal stabilities. Finally, the fabricated ACFs showed excellent and durable antibacterial activities, and the developed method may provide a potential strategy for preparing metal nanowire-grown ACFs.

  1. Rapid end-point quantitation of prion seeding activity with sensitivity comparable to bioassays.

    Directory of Open Access Journals (Sweden)

    Jason M Wilham

    2010-12-01

    prion and amyloid seeding assays. End point dilution RT-QuIC provides a sensitive, rapid, quantitative, and high throughput assay of prion seeding activity.

  2. Monitoring the active conformation of green fluorescent protein (GFP) and β-glucosidase adsorbed on soil particles.

    Science.gov (United States)

    Morales-Belpaire, Isabel; Gerin, Patrick A

    2012-01-01

    In order to determine the effect of various soil components on the activity of proteins, we monitored the fluorescence and the enzymatic activity of, respectively, green fluorescent protein (GFP) and β-glucosidase adsorbed on fine soil particles. We also monitored the activity of these proteins in the presence of components that are representative of soil colloids: a montmorillonite clay, goethite and organic matter extracted from soil. Upon adsorption on clay and goethite, GFP lost its fluorescence properties while β-glucosidase suffered only a partial loss of its catalytic activity. Extractable organic matter had an inactivating role on GFP while it did not cause inactivation of β-glucosidase. When GFP and β-glucosidase adsorbed on particles from natural soil samples, their behaviour was consistent with the behaviour observed for these proteins in the presence of the separate components, suggesting that the macroscopic activity of proteins adsorbed on soil particles corresponds to an average of the activities of proteins adsorbed on a mixture of surfaces. The monitoring of the proteins on soil particles with different organic matter contents has also shown that organic matter can have different effects (protecting or inactivating) on different proteins.

  3. Isotropic Heating of Galaxy Cluster Cores via Rapidly Reorienting Active Galactic Nucleus Jets

    Science.gov (United States)

    Babul, Arif; Sharma, Prateek; Reynolds, Christopher S.

    2013-05-01

    Active galactic nucleus (AGN) jets carry more than sufficient energy to stave off catastrophic cooling of the intracluster medium (ICM) in the cores of cool-core clusters. However, in order to prevent catastrophic cooling, the ICM must be heated in a near-isotropic fashion and narrow bipolar jets with P jet = 1044 - 45 erg s-1, typical of radio AGNs at cluster centers, are inefficient in heating the gas in the transverse direction to the jets. We argue that due to existent conditions in cluster cores, the supermassive black holes (SMBHs) will, in addition to accreting gas via radiatively inefficient flows, experience short stochastic episodes of enhanced accretion via thin disks. In general, the orientation of these accretion disks will be misaligned with the spin axis of the black holes (BHs) and the ensuing torques will cause the BH's spin axis (and therefore the jet axis) to slew and rapidly change direction. This model not only explains recent observations showing successive generations of jet-lobes-bubbles in individual cool-core clusters that are offset from each other in the angular direction with respect to the cluster center, but also shows that AGN jets can heat the cluster core nearly isotropically on the gas cooling timescale. Our model does require that the SMBHs at the centers of cool-core clusters be spinning relatively slowly. Torques from individual misaligned disks are ineffective at tilting rapidly spinning BHs by more than a few degrees. Additionally, since SMBHs that host thin accretion disks will manifest as quasars, we predict that roughly 1-2 rich clusters within z < 0.5 should have quasars at their centers.

  4. Improved Neural Signal Classification in a Rapid Serial Visual Presentation Task Using Active Learning.

    Science.gov (United States)

    Marathe, Amar R; Lawhern, Vernon J; Wu, Dongrui; Slayback, David; Lance, Brent J

    2016-03-01

    The application space for brain-computer interface (BCI) technologies is rapidly expanding with improvements in technology. However, most real-time BCIs require extensive individualized calibration prior to use, and systems often have to be recalibrated to account for changes in the neural signals due to a variety of factors including changes in human state, the surrounding environment, and task conditions. Novel approaches to reduce calibration time or effort will dramatically improve the usability of BCI systems. Active Learning (AL) is an iterative semi-supervised learning technique for learning in situations in which data may be abundant, but labels for the data are difficult or expensive to obtain. In this paper, we apply AL to a simulated BCI system for target identification using data from a rapid serial visual presentation (RSVP) paradigm to minimize the amount of training samples needed to initially calibrate a neural classifier. Our results show AL can produce similar overall classification accuracy with significantly less labeled data (in some cases less than 20%) when compared to alternative calibration approaches. In fact, AL classification performance matches performance of 10-fold cross-validation (CV) in over 70% of subjects when training with less than 50% of the data. To our knowledge, this is the first work to demonstrate the use of AL for offline electroencephalography (EEG) calibration in a simulated BCI paradigm. While AL itself is not often amenable for use in real-time systems, this work opens the door to alternative AL-like systems that are more amenable for BCI applications and thus enables future efforts for developing highly adaptive BCI systems.

  5. Logarithmic conformal field theory

    Science.gov (United States)

    Gainutdinov, Azat; Ridout, David; Runkel, Ingo

    2013-12-01

    Conformal field theory (CFT) has proven to be one of the richest and deepest subjects of modern theoretical and mathematical physics research, especially as regards statistical mechanics and string theory. It has also stimulated an enormous amount of activity in mathematics, shaping and building bridges between seemingly disparate fields through the study of vertex operator algebras, a (partial) axiomatisation of a chiral CFT. One can add to this that the successes of CFT, particularly when applied to statistical lattice models, have also served as an inspiration for mathematicians to develop entirely new fields: the Schramm-Loewner evolution and Smirnov's discrete complex analysis being notable examples. When the energy operator fails to be diagonalisable on the quantum state space, the CFT is said to be logarithmic. Consequently, a logarithmic CFT is one whose quantum space of states is constructed from a collection of representations which includes reducible but indecomposable ones. This qualifier arises because of the consequence that certain correlation functions will possess logarithmic singularities, something that contrasts with the familiar case of power law singularities. While such logarithmic singularities and reducible representations were noted by Rozansky and Saleur in their study of the U (1|1) Wess-Zumino-Witten model in 1992, the link between the non-diagonalisability of the energy operator and logarithmic singularities in correlators is usually ascribed to Gurarie's 1993 article (his paper also contains the first usage of the term 'logarithmic conformal field theory'). The class of CFTs that were under control at this time was quite small. In particular, an enormous amount of work from the statistical mechanics and string theory communities had produced a fairly detailed understanding of the (so-called) rational CFTs. However, physicists from both camps were well aware that applications from many diverse fields required significantly more

  6. High-dose-rate Three-dimensional Conformal Radiotherapy Combined with Active Breathing Control for Stereotactic Body Radiotherapy of Early-stage Non-small-cell Lung Cancer.

    Science.gov (United States)

    Wang, Ruozheng; Yin, Yong; Qin, Yonghui; Yu, Jinming

    2015-12-01

    The purpose of this study was to evaluate the feasibility and benefits of using high-dose-rate three-dimensional conformal radiotherapy (3D-CRT) combined with active breathing control (ABC) for stereotactic body radiotherapy (SBRT) of patients with early-stage non-small-cell lung cancer (NSCLC). Eight patients with early-stage NSCLC underwent CT scans under standard free-breathing (FB) and moderately deep inspiration breath-hold (mDIBH) with ABC. Two high-dose-rate 3D-CRT plans (1000 Mu/min) were designed based on the CT scans with FB and mDIBH. The maximal dose (D1%), minimal dose (D99%), conformity index (CI), and homogeneity index (HI) of the planning target volume (PTV), and dose-volume indices of the organs at risk between each plan were compared. The mean PTV volume decreased from 158.04 cm(3) with FB to 76.90 cm(3) with mDIBH (p < 0.05). When mDIBH was used, increases in the affected lung volume (by 47%), contralateral lung volume (by 55%), and total lung volume (by 50%) were observed compared to FB (p < 0.05). The V5-V40 of the affected lung (Vx represented the percentage volume of organs receiving at least the x Gy), V5-V40 and the mean dose for the total lung, V5-V40 and mean dose of the chest wall, and the maximum dose of the spinal cord were less for mDIBH than FB (p < 0.05). There were no significant differences in CI, HI, D1%, or D99% for the PTV between the plans. In conclusion, high-dose-rate 3D-CRT combined with ABC reduced the radiation dose to the lungs and chest wall without affecting the dose distribution in SBRT of early-stage NSCLC patients. © The Author(s) 2014.

  7. The location and nature of general anesthetic binding sites on the active conformation of firefly luciferase; a time resolved photolabeling study.

    Directory of Open Access Journals (Sweden)

    Sivananthaperumal Shanmugasundararaj

    Full Text Available Firefly luciferase is one of the few soluble proteins that is acted upon by a wide variety of general anesthetics and alcohols; they inhibit the ATP-driven production of light. We have used time-resolved photolabeling to locate the binding sites of alcohols during the initial light output, some 200 ms after adding ATP. The photolabel 3-azioctanol inhibited the initial light output with an IC50 of 200 µM, close to its general anesthetic potency. Photoincorporation of [(3H]3-azioctanol into luciferase was saturable but weak. It was enhanced 200 ms after adding ATP but was negligible minutes later. Sequencing of tryptic digests by HPLC-MSMS revealed a similar conformation-dependence for photoincorporation of 3-azioctanol into Glu-313, a residue that lines the bottom of a deep cleft (vestibule whose outer end binds luciferin. An aromatic diazirine analog of benzyl alcohol with broader side chain reactivity reported two sites. First, it photolabeled two residues in the vestibule, Ser-286 and Ile-288, both of which are implicated with Glu-313 in the conformation change accompanying activation. Second, it photolabeled two residues that contact luciferin, Ser-316 and Ser-349. Thus, time resolved photolabeling supports two mechanisms of action. First, an allosteric one, in which anesthetics bind in the vestibule displacing water molecules that are thought to be involved in light output. Second, a competitive one, in which anesthetics bind isosterically with luciferin. This work provides structural evidence that supports the competitive and allosteric actions previously characterized by kinetic studies.

  8. Colorimetry and SERS dual-mode detection of telomerase activity: combining rapid screening with high sensitivity

    Science.gov (United States)

    Zong, Shenfei; Wang, Zhuyuan; Chen, Hui; Hu, Guohua; Liu, Min; Chen, Peng; Cui, Yiping

    2014-01-01

    As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and surface enhanced Raman scattering (SERS) dual-mode telomerase activity detection method, which has several distinctive advantages. First, colorimetric functionality allows rapid preliminary discrimination of telomerase activity by the naked eye. Second, the employment of SERS technique results in greatly improved detection sensitivity. Third, the combination of colorimetry and SERS into one detection system can ensure highly efficacious and sensitive screening of numerous samples. Besides, the avoidance of polymerase chain reaction (PCR) procedures further guarantees fine reliability and simplicity. Generally, the presented method is realized by an ``elongate and capture'' procedure. To be specific, gold nanoparticles modified with Raman molecules and telomeric repeat complementary oligonucleotide are employed as the colorimetric-SERS bifunctional reporting nanotag, while magnetic nanoparticles functionalized with telomerase substrate oligonucleotide are used as the capturing substrate. Telomerase can synthesize and elongate telomeric repeats onto the capturing substrate. The elongated telomeric repeats subsequently facilitate capturing of the reporting nanotag via hybridization between telomeric repeat and its complementary strand. The captured nanotags can cause a significant difference in the color and SERS intensity of the magnetically separated sediments. Thus both the color and SERS can be used as indicators of the telomerase activity. With fast screening ability and outstanding sensitivity, we anticipate that this method would greatly promote practical application of telomerase-based early-stage cancer diagnosis.As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and

  9. The evolutionary conformation from traditional lecture to active learning in an undergraduate biology course and its effects on student achievement

    Science.gov (United States)

    Diederich, Kirsten Bakke

    In response to the declining number of students in the United States entering into the STEM (science, technology, engineering, and math) disciplines, there has been an attempt to retain student interest in the sciences through the implementation of more active learning in the classroom. Active learning is defined as any instructional method that requires students do something in the classroom rather than simply listen to a lecture (Herreid, 2006). These student centered approaches provide the students with the opportunity to work cooperatively while developing the skills required for critical inquiry. They also help the students make the connections between what is being taught and how it can be applied in a real world setting. Science education researchers have attempted to analyze the efficacy of active learning. Although they find it difficult to compare the data, they state unequivocally that "Active learning is a better strategy for learning than the traditional didactic lecture format" (Prince, 2004). However, even though research supports the efficacy of active learning, instructors find it difficult to adopt this pedagogy into their classrooms due to concerns such as loss of content knowledge and student resistance. This three year qualitative and quantitative study addressed the level of student learning and satisfaction in an introductory vertebrate biology class at a small liberal arts college. The courses were taught by the same instructor using three pedagogical methods; traditional lecture (TL), problem-based learning (PBL), and case-based learning (CBL). Student grades and levels of assessment were compared between the TL and PBL, while student attrition rates, course satisfaction and views of active and group learning were analyzed across all three sections. The evolutionary confirmations from TL to PBL and ultimately the adoption of CBL as the method of choice are discussed from the view of both the faculty member and the students.

  10. Rapid product analysis and increased sensitivity for quantitative determinations of botulinum neurotoxin proteolytic activity.

    Science.gov (United States)

    Rowe, Benjamin; Schmidt, James J; Smith, Leonard A; Ahmed, S Ashraf

    2010-01-15

    The ultimate molecular action of botulinum neurotoxin (BoNT) is a Zn-dependent endoproteolytic activity on one of the three SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins. There are seven serotypes (A-G) of BoNT having distinct cleavage sites on the SNARE substrates. The proteolytic activity is located on the N-terminal light chain (Lc) domain and is used extensively as the primary target toward therapeutic development against botulism. Here we describe an improved method using ultra-performance liquid chromatography (UPLC) whereby quantitative data were obtained in 1/10th the time using 1/20th the sample and solvent volumes compared with a widely used high-performance liquid chromatography (HPLC) method. We also synthesized a VAMP (vesicle-associated membrane protein)-based peptide containing an intact V1 motif that was efficiently used as a substrate by BoNT/D Lc. Although serotype C1 cleaves the serotype A substrate at a bond separated by only one residue, we were able to distinguish the two reactions by UPLC. The new method can accurately quantify as low as 7 pmol of the peptide substrates for BoNT serotypes A, B, C1, and D. We also report here that the catalytic efficiency of serotype A can be stimulated 35-fold by the addition of Triton X-100 to the reaction mixture. Combining the use of Triton X-100 with the newly introduced UPLC method, we were able to accurately detect very low levels of proteolytic activity in a very short time. Sensitivity of the assay and accuracy and rapidity of product analysis should greatly augment efforts in therapeutic development.

  11. Hotspot mutations in KIT receptor differentially modulate its allosterically coupled conformational dynamics: impact on activation and drug sensitivity.

    Directory of Open Access Journals (Sweden)

    Isaure Chauvot de Beauchêne

    2014-07-01

    Full Text Available Receptor tyrosine kinase KIT controls many signal transduction pathways and represents a typical allosterically regulated protein. The mutation-induced deregulation of KIT activity impairs cellular physiological functions and causes serious human diseases. The impact of hotspots mutations (D816H/Y/N/V and V560G/D localized in crucial regulatory segments, the juxtamembrane region (JMR and the activation (A- loop, on KIT internal dynamics was systematically studied by molecular dynamics simulations. The mutational outcomes predicted in silico were correlated with in vitro and in vivo activation rates and drug sensitivities of KIT mutants. The allosteric regulation of KIT in the native and mutated forms is described in terms of communication between the two remote segments, JMR and A-loop. A strong correlation between the communication profile and the structural and dynamical features of KIT in the native and mutated forms was established. Our results provide new insight on the determinants of receptor KIT constitutive activation by mutations and resistance of KIT mutants to inhibitors. Depiction of an intra-molecular component of the communication network constitutes a first step towards an integrated description of vast communication pathways established by KIT in physiopathological contexts.

  12. Conformational coupling between the active site and residues within the K(C)-channel of the Vibrio cholerae cbb3-type (C-family) oxygen reductase.

    Science.gov (United States)

    Ahn, Young O; Mahinthichaichan, Paween; Lee, Hyun Ju; Ouyang, Hanlin; Kaluka, Daniel; Yeh, Syun-Ru; Arjona, Davinia; Rousseau, Denis L; Tajkhorshid, Emad; Adelroth, Pia; Gennis, Robert B

    2014-10-21

    The respiratory chains of nearly all aerobic organisms are terminated by proton-pumping heme-copper oxygen reductases (HCOs). Previous studies have established that C-family HCOs contain a single channel for uptake from the bacterial cytoplasm of all chemical and pumped protons, and that the entrance of the K(C)-channel is a conserved glutamate in subunit III. However, the majority of the K(C)-channel is within subunit I, and the pathway from this conserved glutamate to subunit I is not evident. In the present study, molecular dynamics simulations were used to characterize a chain of water molecules leading from the cytoplasmic solution, passing the conserved glutamate in subunit III and extending into subunit I. Formation of the water chain, which controls the delivery of protons to the K(C)-channel, was found to depend on the conformation of Y241(Vc), located in subunit I at the interface with subunit III. Mutations of Y241(Vc) (to A/F/H/S) in the Vibrio cholerae cbb3 eliminate catalytic activity, but also cause perturbations that propagate over a 28-Å distance to the active site heme b3. The data suggest a linkage between residues lining the K(C)-channel and the active site of the enzyme, possibly mediated by transmembrane helix α7, which contains both Y241(Vc) and the active site cross-linked Y255(Vc), as well as two CuB histidine ligands. Other mutations of residues within or near helix α7 also perturb the active site, indicating that this helix is involved in modulation of the active site of the enzyme.

  13. Conformal Carroll groups

    OpenAIRE

    Duval, C.; Gibbons, G W; Horvathy, P. A.

    2014-01-01

    Conformal extensions of Levy-Leblond's Carroll group, based on geometric properties analogous to those of Newton-Cartan space-time are proposed. The extensions are labelled by an integer $k$. This framework includes and extends our recent study of the Bondi-Metzner-Sachs (BMS) and Newman-Unti (NU) groups. The relation to Conformal Galilei groups is clarified. Conformal Carroll symmetry is illustrated by "Carrollian photons". Motion both in the Newton-Cartan and Carroll spaces may be related t...

  14. Hydrodynamic Voltammetry as a Rapid and Simple Method for Evaluating Soil Enzyme Activities

    Directory of Open Access Journals (Sweden)

    Kazuto Sazawa

    2015-03-01

    Full Text Available Soil enzymes play essential roles in catalyzing reactions necessary for nutrient cycling in the biosphere. They are also sensitive indicators of ecosystem stress, therefore their evaluation is very important in assessing soil health and quality. The standard soil enzyme assay method based on spectroscopic detection is a complicated operation that requires the removal of soil particles. The purpose of this study was to develop a new soil enzyme assay based on hydrodynamic electrochemical detection using a rotating disk electrode in a microliter droplet. The activities of enzymes were determined by measuring the electrochemical oxidation of p-aminophenol (PAP, following the enzymatic conversion of substrate-conjugated PAP. The calibration curves of β-galactosidase (β-gal, β-glucosidase (β-glu and acid phosphatase (AcP showed good linear correlation after being spiked in soils using chronoamperometry. We also performed electrochemical detection using real soils. Hydrodynamic chronoamperometry can be used to assess the AcP in soils, with a detection time of only 90 s. Linear sweep voltammetry was used to measure the amount of PAP released from β-gal and β-glu by enzymatic reaction after 60 min. For the assessment of soil enzymes, the results of hydrodynamic voltammetry assay compared favorably to those using a standard assay procedure, but this new procedure is more user-friendly, rapid and simple.

  15. Rapid prototyping of reflectors for vehicle lighting using laser activated remote phosphor

    Science.gov (United States)

    Lachmayer, Roland; Kloppenburg, Gerolf; Wolf, Alexander

    2015-03-01

    Bright white light sources are of significant importance for automotive front lighting systems. Today's upper class vehicles mainly use HID or LED as light source. As a further step in this development laser diode based systems offer high luminance, efficiency and allow the realization of new styling concepts and new dynamic lighting functions. These white laser diode systems can either be realized by mixing different spectral sources or by combining diodes with specific phosphors. Based on the approach of generating light using a laser and remote phosphor, lighting modules are manufactured. Four blue laser diodes (450 nm) are used to activate a phosphor coating and thus to achieve white light. A segmented paraboloid reflector generates the desired light distribution for an additional car headlamp. We use high speed milling and selective laser melting to build the reflector system for this lighting module. We compare the spectral reflection grade of these materials. Furthermore the generated modules are analyzed regarding their efficiency and light distribution. The use of Rapid Prototyping technologies allows an early validation of the chosen concept and is supposed to reduce cost and time in the product development process significantly. Therefor we discuss costs and times of the applied manufacturing technologies.

  16. Cell-free expression of protein kinase a for rapid activity assays.

    Science.gov (United States)

    Leippe, Donna M; Zhao, Kate Qin; Hsiao, Kevin; Slater, Michael R

    2010-05-19

    Functional protein analysis often calls for lengthy, laborious in vivo protein expression and purification, and can be complicated by the lack of stability of the purified protein. In this study, we demonstrate the feasibility of a simplified procedure for functional protein analysis on magnetic particles using cell-free protein synthesis of the catalytic subunit of human cAMP-dependent protein kinase as a HaloTag((R)) fusion protein. The cell-free protein synthesis systems provide quick access to the protein of interest, while the HaloTag technology provides efficient, covalent protein immobilization of the fusion protein, eliminating the need for further protein purification and minimizing storage-related stability issues. The immobilized cPKA fusion protein is assayed directly on magnetic beads and can be used in inhibitor analyses. The combination of rapid protein synthesis and capture technologies can greatly facilitate the process of protein expression and activity screening, and therefore, can become a valuable tool for functional proteomics studies.

  17. Cell-Free Expression of Protein Kinase a for Rapid Activity Assays

    Directory of Open Access Journals (Sweden)

    Donna M. Leippe

    2010-01-01

    Full Text Available Functional protein analysis often calls for lengthy, laborious in vivo protein expression and purification, and can be complicated by the lack of stability of the purified protein. In this study, we demonstrate the feasibility of a simplified procedure for functional protein analysis on magnetic particles using cell-free protein synthesis of the catalytic subunit of human cAMP-dependent protein kinase as a HaloTag ® fusion protein. The cell-free protein synthesis systems provide quick access to the protein of interest, while the HaloTag technology provides efficient, covalent protein immobilization of the fusion protein, eliminating the need for further protein purification and minimizing storage-related stability issues. The immobilized cPKA fusion protein is assayed directly on magnetic beads and can be used in inhibitor analyses. The combination of rapid protein synthesis and capture technologies can greatly facilitate the process of protein expression and activity screening, and therefore, can become a valuable tool for functional proteomics studies.

  18. Cell-Free Expression of Protein Kinase A for Rapid Activity Assays

    Directory of Open Access Journals (Sweden)

    Donna M. Leippe

    2010-05-01

    Full Text Available Functional protein analysis often calls for lengthy, laborious in vivo protein expression and purification, and can be complicated by the lack of stability of the purified protein. In this study, we demonstrate the feasibility of a simplified procedure for functional protein analysis on magnetic particles using cell-free protein synthesis of the catalytic subunit of human cAMP-dependent protein kinase as a HaloTag® fusion protein. The cell-free protein synthesis systems provide quick access to the protein of interest, while the HaloTag technology provides efficient, covalent protein immobilization of the fusion protein, eliminating the need for further protein purification and minimizing storage-related stability issues. The immobilized cPKA fusion protein is assayed directly on magnetic beads and can be used in inhibitor analyses. The combination of rapid protein synthesis and capture technologies can greatly facilitate the process of protein expression and activity screening, and therefore, can become a valuable tool for functional proteomics studies.

  19. Music training enhances rapid neural plasticity of n1 and p2 source activation for unattended sounds.

    Science.gov (United States)

    Seppänen, Miia; Hämäläinen, Jarmo; Pesonen, Anu-Katriina; Tervaniemi, Mari

    2012-01-01

    Neurocognitive studies have demonstrated that long-term music training enhances the processing of unattended sounds. It is not clear, however, whether music training also modulates rapid (within tens of minutes) neural plasticity for sound encoding. To study this phenomenon, we examined whether adult musicians display enhanced rapid neural plasticity compared to non-musicians. More specifically, we compared the modulation of P1, N1, and P2 responses to standard sounds between four unattended passive blocks. Among the standard sounds, infrequently presented deviant sounds were presented (the so-called oddball paradigm). In the middle of the experiment (after two blocks), an active task was presented. Source analysis for event-related potentials (ERPs) showed that N1 and P2 source activation was selectively decreased in musicians after 15 min of passive exposure to sounds and that P2 source activation was found to be re-enhanced after the active task in musicians. Additionally, ERP analysis revealed that in both musicians and non-musicians, P2 ERP amplitude was enhanced after 15 min of passive exposure but only at the frontal electrodes. Furthermore, in musicians, the N1 ERP was enhanced after the active discrimination task but only at the parietal electrodes. Musical training modulates the rapid neural plasticity reflected in N1 and P2 source activation for unattended regular standard sounds. Enhanced rapid plasticity of N1 and P2 is likely to reflect faster auditory perceptual learning in musicians.

  20. Artificial neural network for prediction of antigenic activity for a major conformational epitope in the hepatitis C virus NS3 protein.

    Science.gov (United States)

    Lara, James; Wohlhueter, Robert M; Dimitrova, Zoya; Khudyakov, Yury E

    2008-09-01

    Insufficient knowledge of general principles for accurate quantitative inference of biological properties from sequences is a major obstacle in the rationale design of proteins with predetermined activities. Due to this deficiency, protein engineering frequently relies on the use of computational approaches focused on the identification of quantitative structure-activity relationship (SAR) for each specific task. In the current article, a computational model was developed to define SAR for a major conformational antigenic epitope of the hepatitis C virus (HCV) non-structural protein 3 (NS3) in order to facilitate a rationale design of HCV antigens with improved diagnostically relevant properties. We present an artificial neural network (ANN) model that connects changes in the antigenic properties and structure of HCV NS3 recombinant proteins representing all 6 HCV genotypes. The ANN performed quantitative predictions of the enzyme immunoassay (EIA) Signal/Cutoff (S/Co) profiles from sequence information alone with 89.8% accuracy. Amino acid positions and physicochemical factors strongly associated with the HCV NS3 antigenic properties were identified. The positions most significantly contributing to the model were mapped on the NS3 3D structure. The location of these positions validates the major associations found by the ANN model between antigenicity and structure of the HCV NS3 proteins. Matlab code is available at the following URL address: http://bio-ai.myeweb.net/box_widget.html

  1. What are the implications of rapid global warming for landslide-triggered turbidity current activity?

    Science.gov (United States)

    Clare, Michael; Peter, Talling; James, Hunt

    2014-05-01

    arithmetic mean recurrence, λ, for the full records (λ=0.007 and 0.0125 Myr). This period of inactivity is coincident with a dramatic carbon isotopic excursion (i.e. warmest part of the IETM) and heavily skews statistical analyses for both records. Dramatic global warming appears to exert a strong control on inhibiting turbidity current activity; whereas the effects of sea level change are not shown to be statistically significant. Rapid global warming is often implicated as a potential landslide trigger, due to dissociation of gas hydrates in response to elevated ocean temperatures. Other studies have suggested that intense global warming may actually be attributed to the atmospheric release of gas hydrates following catastrophic failure of large parts of a continental slope. Either way, a greater intensity of landslide and resultant turbidity current activity would be expected during the IETM; however, our findings are to the contrary. We offer some explanations in relation to potential triggers. Our work suggests that previous rapid global warming at the IETM did not trigger more frequent turbidity currents. This has direct relevance to future assessments relating to landslide-triggered tsunami hazard, and breakage of subsea cables by turbidity currents.

  2. Rapid activated sludge respiration inhibition test performed by CO2 producing rate using a carbon dioxide sensor.

    Science.gov (United States)

    Narita, Noboru; Takahashi, Mitsuo; Shoji, Ryo

    2005-01-01

    The rapid activated sludge inhibition test (rapid ASRI) is one of the promising bioassays to evaluate environmental risk to the ecosystem caused by various pollutants. To improve the sensitivity and stability of ASRI, the CO2 producing rate (CPR) using a carbon dioxide gas sensor was employed to examine the respiration activity of activated sludge and to compare it to that by the conventional activated sludge respiration inhibition test using oxygen uptake rate (OUR) by EC50 values derived from dose response curve. Detection of respiratory activity based on CPR has higher reliability and sensitivity than that of OUR. It should be noted that the sensitivity of CPR for evaluating toxicity is sufficiently high in terms of derived dose response curve of some model environmental pollutants and the resultant EC50 values.

  3. A rapid, sensitive, simple plate assay for detection of microbial alginate lyase activity.

    Science.gov (United States)

    Sawant, Shailesh S; Salunke, Bipinchandra K; Kim, Beom Soo

    2015-09-01

    Screening of microorganisms capable of producing alginate lyase enzyme is commonly carried out by investigating their abilities to grow on alginate-containing solid media plates and occurrence of a clearance zone after flooding the plates with agents such as 10% (w/v) cetyl pyridinium chloride (CPC), which can form complexes with alginate. Although the CPC method is good, advantageous, and routinely used, the agar in the media interferes with the action of CPC, which makes judgment about clearance zones very difficult. In addition, this method takes a minimum of 30 min to obtain the zone of hydrolysis after flooding and the hydrolyzed area is not sharply discernible. An improved plate assay is reported herein for the detection of extracellular alginate lyase production by microorganisms. In this method, alginate-containing agar plates are flooded with Gram's iodine instead of CPC. Gram's iodine forms a bluish black complex with alginate but not with hydrolyzed alginate, giving sharp, distinct zones around the alginate lyase producing microbial colonies within 2-3 min. Gram's iodine method was found to be more effective than the CPC method in terms of visualization and measurement of zone size. The alginate-lyase-activity area indicated using the Gram's iodine method was found to be larger than that indicated by the CPC method. Both methods (CPC and Gram's iodine) showed the largest alginate lyase activity area for Saccharophagus degradans (ATCC 43961) followed by Microbulbifer mangrovi (KCTC 23483), Bacillus cereus (KF801505) and Paracoccus sp. LL1 (KP288668) grown on minimal sea salt medium. The rate of growth and metabolite production in alginate-containing minimal sea salt liquid medium, followed trends similar to that of the zone activity areas for the four bacteria under study. These results suggested that the assay developed in this study of Gram's iodine could be useful to predict the potential of microorganisms to produce alginate lyase. The method also

  4. Structural basis for the antipolymer activity of Hb ζ2β(s)2 trapped in a tense conformation.

    Science.gov (United States)

    Safo, Martin K; Ko, Tzu-Ping; Schreiter, Eric R; Russell, J Eric

    2015-11-05

    The phenotypical severity of sickle-cell disease (SCD) can be mitigated by modifying mutant hemoglobin S (Hb S, Hb α2β(s)2) to contain embryonic ζ-globin in place of adult α-globin subunits (Hb ζ2β(s)2). Crystallographical analyses of liganded Hb ζζ2β(s)2, though, demonstrate a tense (T-state) quaternary structure that paradoxically predicts its participation in--rather than its exclusion from--pathological deoxyHb S polymers. We resolved this structure-function conundrum by examining the effects of α→ζ exchange on the characteristics of specific amino acids that mediate sickle polymer assembly. Superposition analyses of the β(s) subunits of T-state deoxyHb α2β(s)2 and T-state CO-liganded Hb ζ2β(s)2 reveal significant displacements of both mutant β(s)Val6 and conserved β-chain contact residues, predicting weakening of corresponding polymer-stabilizing interactions. Similar comparisons of the α- and ζ-globin subunits implicate four amino acids that are either repositioned or undergo non-conservative substitution, abrogating critical polymer contacts. CO-Hb ζ2β(s)2 additionally exhibits a unique trimer-of-heterotetramers crystal packing that is sustained by novel intermolecular interactions involving the pathological β(s)Val6, contrasting sharply with the classical double-stranded packing of deoxyHb S. Finally, the unusually large buried solvent-accessible surface area for CO-Hb ζ2β(s)2 suggests that it does not co-assemble with deoxyHb S in vivo. In sum, the antipolymer activities of Hb ζ2β(s)2 appear to arise from both repositioning and replacement of specific α- and β(s)-chain residues, favoring an alternate T-state solution structure that is excluded from pathological deoxyHb S polymers. These data account for the antipolymer activity of Hb ζ2β(s)2, and recommend the utility of SCD therapeutics that capitalize on α-globin exchange strategies.

  5. Conformational stability of calreticulin

    DEFF Research Database (Denmark)

    Jørgensen, Charlotte S; Trandum, Christa; Larsen, Nanna Brink

    2005-01-01

    The conformational stability of calreticulin was investigated. Apparent unfolding temperatures (Tm) increased from 31 degrees C at pH 5 to 51 degrees C at pH 9, but electrophoretic analysis revealed that calreticulin oligomerized instead of unfolding. Structural analyses showed that the single C......-terminal alpha-helix was of major importance to the conformational stability of calreticulin....

  6. Conformational stability of calreticulin

    DEFF Research Database (Denmark)

    Jørgensen, C.S.; Trandum, C.; Larsen, N.

    2005-01-01

    The conformational stability of calreticulin was investigated. Apparent unfolding temperatures (T-m) increased from 31 degrees C at pH 5 to 51 degrees C at pH 9, but electrophoretic analysis revealed that calreticulin oligomerized instead of unfolding. Structural analyses showed that the single C......-terminal a-helix was of major importance to the conformational stability of calreticulin....

  7. Assessment of conformational, spectral, antimicrobial activity, chemical reactivity and NLO application of Pyrrole-2,5-dicarboxaldehyde bis(oxaloyldihydrazone)

    Science.gov (United States)

    Rawat, Poonam; Singh, R. N.

    2015-04-01

    An orange colored pyrrole dihydrazone: Pyrrole-2,5-dicarboxaldehyde bis(oxaloyldihydrazone) (PDBO) has been synthesized by reaction of oxalic acid dihydrazide with 2,5 diformyl-1H-pyrrole and has been characterized by spectroscopic analysis (1H, 13C NMR, UV-visible, FT-IR and DART Mass). The properties of the compound has been evaluated using B3LYP functional and 6-31G(d,p)/6-311+G(d,p) basis set. The symmetric (3319, 3320 cm-1) and asymmetric (3389, 3382 cm-1) stretching wave number confirm free NH2 groups in PDBO. NBO analysis shows, inter/intra molecular interactions within the molecule. Topological parameters have been analyzed by QTAIM theory and provide the existence of intramolecular hydrogen bonding (N-H⋯O). The local reactivity descriptors analyses determine the reactive sites within molecule. The calculated first hyperpolarizability value (β0 = 23.83 × 10-30 esu) of pyrrole dihydrazone shows its suitability for non-linear optical (NLO) response. The preliminary bioassay suggested that the PDBO exhibits relatively good antibacterial and fungicidal activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes, Candida albicans, Aspergillus niger. The local reactivity descriptors - Fukui functions (fk+, fk-), local softnesses (sk+, sk-) and electrophilicity indices (ωk+, ωk-) analyses have been used to determine the reactive sites within molecule.

  8. Antibacterial activity of chensinin-1b, a peptide with a random coil conformation, against multiple-drug-resistant Pseudomonas aeruginosa.

    Science.gov (United States)

    Shang, Dejing; Meng, Xin; Zhang, Dongdong; Kou, Zhiru

    2017-11-01

    Nosocomial infections caused by Pseudomonas aeruginosa are difficult to treat due to the low permeability of its outer membrane as well as to its remarkable ability to acquire further resistance to antibiotics. Chensinin-1b exhibited antibacterial activity against the tested multiple-drug-resistant bacteria with a MIC ranging between 1.56 and 50μM, except E. cloacae strain 0320 (MREC0320), P. fluorescens strain 0322 (MRPF0322) and E. aerogenes strain 0320 (MREA0320). However, the MIC (25μM) of chensinin-1b to multiple-drug-resistant P. aeruginosa strain (MRPA 0108) was 16-fold higher than that observed to P. aeruginosa susceptible strain CGMCC 1.860 (PA1860). Chensinin-1b was able to disturb the integration of the cytoplasmic membrane of PA1860 and MRPA0108 cells similarly, but the outer membrane permeability of MRPA0108 cells was significantly lower. This low permeability was associated with increased expression of lipopolysaccharide (LPS) in the outer membrane and a decrease in negatively charged phospholipids in the outer membrane leaflet. In addition, the biofilm of MRPA0108 was responsible for the reduced susceptibility to chensinin-1b. A higher concentration of chensinin-1b (12.5µM) was required to maximally inhibit the formation of MRPA0108 biofilm. Notably, chensinin-1b inhibited the formation of MRPA0108 biofilm at concentrations below its MIC value by down-regulating the level of PelA, algD, and PslA gene transcription. Importantly, chensinin-1b had a significant antibacterial effect against MRPA0108 in vivo. Administration of chensinin-1b to mice infected with MRPA 0108 significantly increased survival by 50-70%. Moreover, chensinin-1b reduced the production of pro-inflammatory mediators and correspondingly reduced lung and liver tissue damage in the mouse model of septic shock induced by MRPA 0108. Collectively, these results suggest that chensinin-1b could be an effective antibiotic against multiple-drug-resistant bacterial strains. Copyright

  9. 20 CFR 665.330 - Are the NAFTA-TAA program requirements for rapid response also required activities?

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Are the NAFTA-TAA program requirements for... WORKFORCE INVESTMENT ACT Rapid Response Activities § 665.330 Are the NAFTA-TAA program requirements for... WIA are made available to workers who, under the NAFTA Implementation Act (Public Law 103-182), are...

  10. SLITHER: a web server for generating contiguous conformations of substrate molecules entering into deep active sites of proteins or migrating through channels in membrane transporters.

    Science.gov (United States)

    Lee, Po-Hsien; Kuo, Kuei-Ling; Chu, Pei-Ying; Liu, Eric M; Lin, Jung-Hsin

    2009-07-01

    Many proteins use a long channel to guide the substrate or ligand molecules into the well-defined active sites for catalytic reactions or for switching molecular states. In addition, substrates of membrane transporters can migrate to another side of cellular compartment by means of certain selective mechanisms. SLITHER (http://bioinfo.mc.ntu.edu.tw/slither/or http://slither.rcas.sinica.edu.tw/) is a web server that can generate contiguous conformations of a molecule along a curved tunnel inside a protein, and the binding free energy profile along the predicted channel pathway. SLITHER adopts an iterative docking scheme, which combines with a puddle-skimming procedure, i.e. repeatedly elevating the potential energies of the identified global minima, thereby determines the contiguous binding modes of substrates inside the protein. In contrast to some programs that are widely used to determine the geometric dimensions in the ion channels, SLITHER can be applied to predict whether a substrate molecule can crawl through an inner channel or a half-channel of proteins across surmountable energy barriers. Besides, SLITHER also provides the list of the pore-facing residues, which can be directly compared with many genetic diseases. Finally, the adjacent binding poses determined by SLITHER can also be used for fragment-based drug design.

  11. Patient characteristics, interventions and outcomes of 1151 rapid response team activations in a tertiary hospital: a prospective study.

    Science.gov (United States)

    White, K; Scott, I A; Bernard, A; McCulloch, K; Vaux, A; Joyce, C; Sullivan, C M

    2016-12-01

    The characteristics of mature contemporary rapid response systems are unclear. To determine the patient characteristics, processes and outcomes, both in-hospital and post-discharge, of a well-established rapid response system in a tertiary adult hospital. This is a prospective study of consecutive rapid response team (RRT) activations between 1 July and 25 November 2015. Variables included patient characteristics, timing, location and triggers of RRT activations, interventions undertaken, mortality and readmission status at 28 days post-discharge. A total of 1151 RRT activations was analysed (69.1 per 1000 admissions), involving 800 patients, of whom 81.5% were emergency admissions. A total of 351 (30.5%) activations comprised repeat activations for the same patient. Most activations (723; 62.8%) occurred out of hours, and 495 (43%) occurred within 48 h of admission. Hypotension, decreased level of consciousness and oxygen desaturation were the most common triggers. Advanced life support was undertaken in less than 7%; 198 (17.2%) responses led to transfer to higher-level care units. Acute resuscitation plans were noted for only 29.1% of RRT activations, with 80.3% stipulating supportive care only. A total of 103 (12.6%) patients died in hospital, equalling 14 deaths per 100 RRT activations. At 28 days, 150 (18.8%) patients had died, significantly more among those with multiple versus single RRT activations (24.9 vs 16.6%; odds ratio 1.66, 95% confidence interval 1.31-2.44; P = 0.013). Relatively few RRT activations are associated with acute resuscitation plans, and most interventions during RRT responses are low level. The high rate of post-RRT deaths and transfers to higher-level care units calls for the prospective identification of such patients in targeting appropriate care. © 2016 Royal Australasian College of Physicians.

  12. Rapid EEG desynchronization and EMG activation induced by intravenous cocaine in freely moving rats: a peripheral, nondopamine neural triggering.

    Science.gov (United States)

    Kiyatkin, Eugene A; Smirnov, Michael S

    2010-02-01

    Many important physiological, behavioral, and psychoemotional effects of intravenous (IV) cocaine (COC) are too fast and transient compared with pharmacokinetic predictions, suggesting a possible involvement of peripheral neural mechanisms in their triggering. In the present study, we examined changes in cortical electroencephalogram (EEG) and neck electromyogram (EMG) induced in freely moving rats by IV COC administration at low, reinforcing doses (0.25-1.0 mg/kg) and compared them with those induced by an auditory stimulus and IV COC methiodide, which cannot cross the blood-brain barrier. We found that COC induces rapid, strong, and prolonged EEG desynchronization, associated with decrease in alpha and increase in beta and gamma activities, and EMG activation and that both begin within 2-6 s following the start of a 10-s injection; immediate components of this effect were dose independent. The rapid COC-induced changes in EEG and EMG resembled those induced by an auditory stimulus; the latter effects had shorter onset latencies and durations and were fully blocked during urethane anesthesia. Although urethane anesthesia completely blocked COC-induced EMG activation and rapid components of EEG response, COC still induced EEG desynchronization that was much weaker, greatly delayed (approximately 60 s), and associated with tonic decreases in delta and increases in alpha, beta, and gamma activities. Surprisingly, IV saline delivered during slow-wave sleep (but not quite wakefulness) also induced a transient EEG desynchronization but without changes in EMG activity; these effects were also fully blocked during anesthesia. Peripherally acting COC methiodide fully mimicked rapid EEG and EMG effects of regular COC, but the effects at an equimolar dose were less prolonged than those with regular COC. These data suggest that in awake animals IV COC, like somato-sensory stimuli, induces cortical activation and a subsequent motor response via its action on peripheral neural

  13. Segregation and rapid turnover of EDEM1 by an autophagy-like mechanism modulates standard ERAD and folding activities.

    Science.gov (United States)

    Calì, Tito; Galli, Carmela; Olivari, Silvia; Molinari, Maurizio

    2008-07-04

    EDEM1 is a crucial regulator of endoplasmic reticulum (ER)-associated degradation (ERAD) that extracts non-native glycopolypeptides from the calnexin chaperone system. Under normal growth conditions, the intralumenal level of EDEM1 must be low to prevent premature interruption of ongoing folding programs. We report that in unstressed cells, EDEM1 is segregated from the bulk ER into LC3-I-coated vesicles and is rapidly degraded. The rapid turnover of EDEM1 is regulated by a novel mechanism that shows similarities but is clearly distinct from macroautophagy. Cells with defective EDEM1 turnover contain unphysiologically high levels of EDEM1, show enhanced ERAD activity and are characterized by impaired capacity to efficiently complete maturation of model glycopolypeptides. We define as ERAD tuning the mechanisms operating in the mammalian ER at steady state to offer kinetic advantage to folding over disposal of unstructured nascent chains by selective and rapid degradation of ERAD regulators.

  14. Conformal expansions and renormalons

    CERN Document Server

    Brodsky, S J; Grunberg, G; Rathsman, J; Brodsky, Stanley J.; Gardi, Einan; Grunberg, Georges; Rathsman, Johan

    2001-01-01

    The coefficients in perturbative expansions in gauge theories are factoriallyincreasing, predominantly due to renormalons. This type of factorial increaseis not expected in conformal theories. In QCD conformal relations betweenobservables can be defined in the presence of a perturbative infraredfixed-point. Using the Banks-Zaks expansion we study the effect of thelarge-order behavior of the perturbative series on the conformal coefficients.We find that in general these coefficients become factorially increasing.However, when the factorial behavior genuinely originates in a renormalonintegral, as implied by a postulated skeleton expansion, it does not affect theconformal coefficients. As a consequence, the conformal coefficients willindeed be free of renormalon divergence, in accordance with previousobservations concerning the smallness of these coefficients for specificobservables. We further show that the correspondence of the BLM method with theskeleton expansion implies a unique scale-setting procedure. Th...

  15. Conformal expansions and renormalons

    CERN Document Server

    Gardi, E; Gardi, Einan; Grunberg, Georges

    2001-01-01

    The large-order behaviour of QCD is dominated by renormalons. On the other hand renormalons do not occur in conformal theories, such as the one describing the infrared fixed-point of QCD at small beta_0 (the Banks--Zaks limit). Since the fixed-point has a perturbative realization, all-order perturbative relations exist between the conformal coefficients, which are renormalon-free, and the standard perturbative coefficients, which contain renormalons. Therefore, an explicit cancellation of renormalons should occur in these relations. The absence of renormalons in the conformal limit can thus be seen as a constraint on the structure of the QCD perturbative expansion. We show that the conformal constraint is non-trivial: a generic model for the large-order behaviour violates it. We also analyse a specific example, based on a renormalon-type integral over the two-loop running-coupling, where the required cancellation does occur.

  16. Group Size and Conformity

    OpenAIRE

    Bond, Rod

    2005-01-01

    Abstract This paper reviews theory and research on the relationship between group size and conformity and presents a meta-analysis of 125 Asch-type conformity studies. It questions the assumption of a single function made in formal models of social influence and proposes instead that the function will vary depending on which social influence process predominates. It is argued that normative influence is lik...

  17. Conformable variational iteration method

    Directory of Open Access Journals (Sweden)

    Omer Acan

    2017-02-01

    Full Text Available In this study, we introduce the conformable variational iteration method based on new defined fractional derivative called conformable fractional derivative. This new method is applied two fractional order ordinary differential equations. To see how the solutions of this method, linear homogeneous and non-linear non-homogeneous fractional ordinary differential equations are selected. Obtained results are compared the exact solutions and their graphics are plotted to demonstrate efficiency and accuracy of the method.

  18. Quantum massive conformal gravity

    Energy Technology Data Exchange (ETDEWEB)

    Faria, F.F. [Universidade Estadual do Piaui, Centro de Ciencias da Natureza, Teresina, PI (Brazil)

    2016-04-15

    We first find the linear approximation of the second plus fourth order derivative massive conformal gravity action. Then we reduce the linearized action to separated second order derivative terms, which allows us to quantize the theory by using the standard first order canonical quantization method. It is shown that quantum massive conformal gravity is renormalizable but has ghost states. A possible decoupling of these ghost states at high energies is discussed. (orig.)

  19. Delineating the conformal window

    DEFF Research Database (Denmark)

    Frandsen, Mads Toudal; Pickup, Thomas; Teper, Michael

    2011-01-01

    We identify and characterise the conformal window in gauge theories relevant for beyond the standard model building, e.g. Technicolour, using the criteria of metric confinement and causal analytic couplings, which are known to be consistent with the phase diagram of supersymmetric QCD from Seiberg...... duality. Using these criteria we find perturbation theory to be consistent throughout the predicted conformal window for several of these gauge theories and we discuss recent lattice results in the light of our findings....

  20. The ABC of protein kinase conformations.

    Science.gov (United States)

    Möbitz, Henrik

    2015-10-01

    Due to their involvement in human diseases, protein kinases are an important therapeutic target class. Conformation is a key concept for understanding how functional activity, inhibition and sequence are linked. We assemble and annotate the mammalian structural kinome from the Protein Data Bank on the basis of a universal residue nomenclature. We identify a torsion angle around the Gly of the DFG-motif whose sharp distribution profile corresponds to three eclipsed conformations. This allows the definition a small set of clusters whose distribution shows a bias for the active conformation. A common rationale links the active and inactive state: stabilization of the active conformation, as well as inactivation by displacement of helix-αC or the DFG-motif is governed by the interaction between helix-αC and the DFG motif. In particular, the conformation of the DFG-motif is tightly correlated with the propensity of helix-αC displacement. Our analysis reveals detailed mechanisms for the displacement of helix-αC and the DFG and improves our understanding of the role of individual residues. By pooling conformations from the whole structural kinome, the energetic contributions of sequence and extrinsic factors can be estimated in free energy analyses. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Lipid Extract of Mycoplasma penetrans Proteinase K-Digested Lipid-Associated Membrane Proteins Rapidly Activates NF-κB and Activator Protein 1

    OpenAIRE

    Feng, Shaw-Huey; Lo, Shyh-Ching

    1999-01-01

    Lipid-associated membrane proteins (LAMPs) of Mycoplasma penetrans rapidly induced macrophages to produce proinflammatory cytokines such as tumor necrosis factor alpha (TNF-α). Our analysis showed that the macrophage-stimulating activity of TNF-α production was mainly attributable to a lipid extractable component(s) in the LAMP preparation. Since induction of gene expression is normally preceded by activation of transcriptional factors that bind to their specific recognition elements located ...

  2. PubChem3D: Similar conformers

    Directory of Open Access Journals (Sweden)

    Bolton Evan E

    2011-05-01

    Full Text Available Abstract Background PubChem is a free and open public resource for the biological activities of small molecules. With many tens of millions of both chemical structures and biological test results, PubChem is a sizeable system with an uneven degree of available information. Some chemical structures in PubChem include a great deal of biological annotation, while others have little to none. To help users, PubChem pre-computes "neighboring" relationships to relate similar chemical structures, which may have similar biological function. In this work, we introduce a "Similar Conformers" neighboring relationship to identify compounds with similar 3-D shape and similar 3-D orientation of functional groups typically used to define pharmacophore features. Results The first two diverse 3-D conformers of 26.1 million PubChem Compound records were compared to each other, using a shape Tanimoto (ST of 0.8 or greater and a color Tanimoto (CT of 0.5 or greater, yielding 8.16 billion conformer neighbor pairs and 6.62 billion compound neighbor pairs, with an average of 253 "Similar Conformers" compound neighbors per compound. Comparing the 3-D neighboring relationship to the corresponding 2-D neighboring relationship ("Similar Compounds" for molecules such as caffeine, aspirin, and morphine, one finds unique sets of related chemical structures, providing additional significant biological annotation. The PubChem 3-D neighboring relationship is also shown to be able to group a set of non-steroidal anti-inflammatory drugs (NSAIDs, despite limited PubChem 2-D similarity. In a study of 4,218 chemical structures of biomedical interest, consisting of many known drugs, using more diverse conformers per compound results in more 3-D compound neighbors per compound; however, the overlap of the compound neighbor lists per conformer also increasingly resemble each other, being 38% identical at three conformers and 68% at ten conformers. Perhaps surprising is that the average

  3. Lipid Extract of Mycoplasma penetrans Proteinase K-Digested Lipid-Associated Membrane Proteins Rapidly Activates NF-κB and Activator Protein 1

    Science.gov (United States)

    Feng, Shaw-Huey; Lo, Shyh-Ching

    1999-01-01

    Lipid-associated membrane proteins (LAMPs) of Mycoplasma penetrans rapidly induced macrophages to produce proinflammatory cytokines such as tumor necrosis factor alpha (TNF-α). Our analysis showed that the macrophage-stimulating activity of TNF-α production was mainly attributable to a lipid extractable component(s) in the LAMP preparation. Since induction of gene expression is normally preceded by activation of transcriptional factors that bind to their specific recognition elements located in the upstream promoter region, we examined the activity of transcriptional factors, namely, NF-κB and activator protein 1 (AP-1), in thioglycolate exudate peritoneal (TEP) macrophages treated with M. penetrans lipid extract of proteinase K (PK)-digested LAMPs. Initially, in the nuclei of unstimulated TEP cells, there was only a low basal level of active AP-1, and the active form of NF-κB could not be detected. M. penetrans lipid extract of PK-digested LAMPs activated both NF-κB and AP-1 in TEP macrophages within 15 min. The markedly increased activities of both factors gradually declined and dissipated after 2 h. Parallel to the rapid increase of NF-κB and AP-1, the TNF-α transcript also increased significantly 15 min after the stimulation. The high-level expression of TNF-α persisted over 2 h. Dexamethasone blocked the activation of both NF-κB and AP-1 and suppressed the production of TNF-α in TEP macrophages stimulated by M. penetrans lipid extract of PK-digested LAMPs. Our study demonstrates that the M. penetrans lipid extract of PK-digested LAMP is a potent activator for NF-κB and AP-1 in murine TEP macrophages. Our results also suggest that high-level expression of TNF-α in cells induced by M. penetrans lipid extract of PK-digested LAMPs is associated with rapid activation of transcriptional factors NF-κB and AP-1. PMID:10338504

  4. Lipid extract of Mycoplasma penetrans proteinase K-digested lipid-associated membrane proteins rapidly activates NF-kappaB and activator protein 1.

    Science.gov (United States)

    Feng, S H; Lo, S C

    1999-06-01

    Lipid-associated membrane proteins (LAMPs) of Mycoplasma penetrans rapidly induced macrophages to produce proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha). Our analysis showed that the macrophage-stimulating activity of TNF-alpha production was mainly attributable to a lipid extractable component(s) in the LAMP preparation. Since induction of gene expression is normally preceded by activation of transcriptional factors that bind to their specific recognition elements located in the upstream promoter region, we examined the activity of transcriptional factors, namely, NF-kappaB and activator protein 1 (AP-1), in thioglycolate exudate peritoneal (TEP) macrophages treated with M. penetrans lipid extract of proteinase K (PK)-digested LAMPs. Initially, in the nuclei of unstimulated TEP cells, there was only a low basal level of active AP-1, and the active form of NF-kappaB could not be detected. M. penetrans lipid extract of PK-digested LAMPs activated both NF-kappaB and AP-1 in TEP macrophages within 15 min. The markedly increased activities of both factors gradually declined and dissipated after 2 h. Parallel to the rapid increase of NF-kappaB and AP-1, the TNF-alpha transcript also increased significantly 15 min after the stimulation. The high-level expression of TNF-alpha persisted over 2 h. Dexamethasone blocked the activation of both NF-kappaB and AP-1 and suppressed the production of TNF-alpha in TEP macrophages stimulated by M. penetrans lipid extract of PK-digested LAMPs. Our study demonstrates that the M. penetrans lipid extract of PK-digested LAMP is a potent activator for NF-kappaB and AP-1 in murine TEP macrophages. Our results also suggest that high-level expression of TNF-alpha in cells induced by M. penetrans lipid extract of PK-digested LAMPs is associated with rapid activation of transcriptional factors NF-kappaB and AP-1.

  5. Injury-induced rapid activation of MAPK signaling in dechorionated eggs and larvae of the silkworm Bombyx mori.

    Science.gov (United States)

    Gu, Shi-Hong; Chen, Chien-Hung

    2017-04-01

    Previous study showed that diapause in Bombyx mori eggs can be terminated by dechorionation and that activation in the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) in dechorionated cultured eggs is involved in diapause termination. In the present study, the possible mechanism underlying activation of ERK upon dechorionation was further investigated. Results showed that mechanical injury of diapause eggs without medium incubation also resulted in rapid increase in the phospho-ERK levels and that injury increased the phospho-ERK levels at different stages of both diapause eggs and eggs in which diapause initiation was prevented by HCl. Effects of anaerobiosis on dechorionation-stimulated phospho-ERK levels showed that the mechanical injury itself but not the dramatic increase in oxygen uptake upon injury is involved in a rapid activation of ERK. Chemical anaerobiosis on dechorionation-stimulated phospho-ERK levels and the in vivo effect of anaerobiosis showed that the supply of oxygen also plays a role in ERK signaling. In addition, injury induced the phosphorylation of c-jun N-terminal kinases (JNKs) and p38 kinase, components of two parallel MAPK pathways. A kinase assay showed a dramatic increase in JNK kinase activity in egg lysates upon injury. When newly hatched first instar larvae were injured, an increase in the phospho-ERK levels similar to that in dechorionated eggs was observed. From the results, we hypothesize that the injury-induced rapid activation of MAPK signaling, which serves as a natural signal for embryonic development, is related to diapause termination in dechorionated eggs. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  6. Inactivation of active thrombin-activable fibrinolysis inhibitor takes place by a process that involves conformational instability rather than proteolytic cleavage

    NARCIS (Netherlands)

    Marx, PF; Hackeng, TM; Dawson, PE; Griffin, JH; Meijers, JCM; Bouma, Bonno N.

    2000-01-01

    Thrombin-activable fibrinolysis inhibitor (TAFI) is present in the circulation as an inactive zymogen. Thrombin converts TAFI to a carboxypeptidase B-like enzyme (TAFIa) by cleaving at Arg(92) in a process accelerated by the cofactor, thrombomodulin. TAFIa attenuates fibrinolysis. TAFIa can be

  7. Conformal invariance of curvature perturbation

    CERN Document Server

    Gong, Jinn-Ouk; Park, Wan Il; Sasaki, Misao; Song, Yong-Seon

    2011-01-01

    We show that in the single component situation all perturbation variables in the comoving gauge are conformally invariant to all perturbation orders. Generally we identify a special time slicing, the uniform-conformal transformation slicing, where all perturbations are again conformally invariant to all perturbation orders. We apply this result to the delta N formalism, and show its conformal invariance.

  8. Conformal invariance of curvature perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Jinn-Ouk [Theory Division, CERN, CH-1211 Genève 23 (Switzerland); Hwang, Jai-chan [Department of Astronomy and Atmospheric Sciences, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Park, Wan Il; Sasaki, Misao; Song, Yong-Seon, E-mail: jinn-ouk.gong@cern.ch, E-mail: jchan@knu.ac.kr, E-mail: wipark@kias.re.kr, E-mail: misao@yukawa.kyoto-u.ac.jp, E-mail: ysong@kias.re.kr [Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of)

    2011-09-01

    We show that in the single component situation all perturbation variables in the comoving gauge are conformally invariant to all perturbation orders. Generally we identify a special time slicing, the uniform-conformal transformation slicing, where all perturbations are again conformally invariant to all perturbation orders. We apply this result to the δN formalism, and show its conformal invariance.

  9. 20 CFR 665.320 - May other activities be undertaken as part of rapid response?

    Science.gov (United States)

    2010-04-01

    ... agencies and officials, employer associations, technical councils or other industry business councils, and... in capacity building activities, including providing information about innovative and successful... employee skill upgrading; and (3) Linkages with economic development activities at the Federal, State and...

  10. Objective interpretation as conforming interpretation

    Directory of Open Access Journals (Sweden)

    Lidka Rodak

    2011-12-01

    Full Text Available The practical discourse willingly uses the formula of “objective interpretation”, with no regards to its controversial nature that has been discussed in literature.The main aim of the article is to investigate what “objective interpretation” could mean and how it could be understood in the practical discourse, focusing on the understanding offered by judicature.The thesis of the article is that objective interpretation, as identified with textualists’ position, is not possible to uphold, and should be rather linked with conforming interpretation. And what this actually implies is that it is not the virtue of certainty and predictability – which are usually associated with objectivity- but coherence that makes the foundation of applicability of objectivity in law.What could be observed from the analyses, is that both the phenomenon of conforming interpretation and objective interpretation play the role of arguments in the interpretive discourse, arguments that provide justification that interpretation is not arbitrary or subjective. With regards to the important part of the ideology of legal application which is the conviction that decisions should be taken on the basis of law in order to exclude arbitrariness, objective interpretation could be read as a question “what kind of authority “supports” certain interpretation”? that is almost never free of judicial creativity and judicial activism.One can say that, objective and conforming interpretation are just another arguments used in legal discourse.

  11. Can turbidity caused by Corophium volutator (Pallas) activity be used to assess sediment toxicity rapidly?

    Science.gov (United States)

    Briggs, Andrew D; Greenwood, Naomi; Grant, Alastair

    2003-04-01

    The standard toxicity test organism, Corophium volutator, exhibits a behavioural response to contaminated sediments that causes increased turbidity of overlying water. We quantify the effects of this response to an estuarine sediment spiked with copper and hydrocarbon contaminated sediments from an oil installation in the North Sea. Turbidity measured 24 h after the start of a toxicity test shows a strong relationship with contaminant concentrations and with mortality after 10 days. Turbidity measurements can therefore give a rapid indication of sediment toxicity, permitting a reduction in storage time of sediments to be used in dilution series and toxicity identification evaluation (TIE) tests, reducing the likelihood of contaminants degrading prior to testing.

  12. Rapid investigation of α-glucosidase inhibitory activity of Phaleria macrocarpa extracts using FTIR-ATR based fingerprinting

    Directory of Open Access Journals (Sweden)

    Sabina Easmin

    2017-04-01

    Full Text Available Phaleria macrocarpa, known as “Mahkota Dewa”, is a widely used medicinal plant in Malaysia. This study focused on the characterization of α-glucosidase inhibitory activity of P. macrocarpa extracts using Fourier transform infrared spectroscopy (FTIR-based metabolomics. P. macrocarpa and its extracts contain thousands of compounds having synergistic effect. Generally, their variability exists, and there are many active components in meager amounts. Thus, the conventional measurement methods of a single component for the quality control are time consuming, laborious, expensive, and unreliable. It is of great interest to develop a rapid prediction method for herbal quality control to investigate the α-glucosidase inhibitory activity of P. macrocarpa by multicomponent analyses. In this study, a rapid and simple analytical method was developed using FTIR spectroscopy-based fingerprinting. A total of 36 extracts of different ethanol concentrations were prepared and tested on inhibitory potential and fingerprinted using FTIR spectroscopy, coupled with chemometrics of orthogonal partial least square (OPLS at the 4000–400 cm−1 frequency region and resolution of 4 cm−1. The OPLS model generated the highest regression coefficient with R2Y = 0.98 and Q2Y = 0.70, lowest root mean square error estimation = 17.17, and root mean square error of cross validation = 57.29. A five-component (1+4+0 predictive model was build up to correlate FTIR spectra with activity, and the responsible functional groups, such as –CH, –NH, –COOH, and –OH, were identified for the bioactivity. A successful multivariate model was constructed using FTIR-attenuated total reflection as a simple and rapid technique to predict the inhibitory activity.

  13. Hot Conformal Gauge Theories

    DEFF Research Database (Denmark)

    Mojaza, Matin; Pica, Claudio; Sannino, Francesco

    2010-01-01

    in such a way that the theory develops a perturbative stable infrared fixed point at zero temperature. Due to large distance conformality we trade the coupling constant with its fixed point value and define a reduced free energy which depends only on the number of flavors, colors and matter representation. We...... show that the reduced free energy changes sign, at the second, fifth and sixth order in the coupling, when decreasing the number of flavors from the upper end of the conformal window. If the change in sign is interpreted as signal of an instability of the system then we infer a critical number...... of flavors. Surprisingly this number, if computed to the order g^2, agrees with previous predictions for the lower boundary of the conformal window for nonsupersymmetric gauge theories. The higher order results tend to predict a higher number of critical flavors. These are universal properties, i...

  14. Human activity accelerating the rapid desertification of the Mu Us Sandy Lands, North China

    Science.gov (United States)

    Miao, Yunfa; Jin, Heling; Cui, Jianxin

    2016-01-01

    Over the past several thousand years, arid and semiarid China has experienced a series of asynchronous desertification events in its semiarid sandy and desert regions, but the precise identification of the driving forces of such events has remained elusive. In this paper we identify two rapid desertification events (RDEs) at ~4.6 ± 0.2 ka BP and ~3.3 ± 0.2 ka BP from the JJ Profile, located in the eastern Mu Us Sandy Lands. These RDEs appear to have occurred immediately following periods marked by persistently frequent and intense fires. We argue that such fire patterns, directly linked to an uncontrolled human use of vegetation as fuel, played a key role in accelerating RDEs by ensuring that the land surface was degraded beyond the threshold required for rapid desertification. This would suggest that the future use of a massive and sustained ecological program of vegetation rehabilitation should reduce the risk of destructive fire. PMID:26961705

  15. Dosimetric study of volumetric arc modulation with RapidArc and intensity-modulated radiotherapy in patients with cervical cancer and comparison with 3-dimensional conformal technique for definitive radiotherapy in patients with cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Guy, Jean-Baptiste [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Falk, Alexander T. [Department of Radiation Oncology, Centre Antoine Lacassagne, Nice (France); Auberdiac, Pierre [Department of Radiation Oncology, Clinique Claude Bernard, Albi (France); Cartier, Lysian; Vallard, Alexis [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Ollier, Edouard [Department of Pharmacology-Toxicology, Centre Hospitalier Universitaire de Saint-Etienne, Saint-Priest en Jarez (France); Trone, Jane-Chloé; Khodri, Moustapha [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Chargari, Cyrus [Department of Radiation Oncology, Hôpital d’instruction de Armées du Val-de-Grâce, Paris (France); Magné, Nicolas, E-mail: nicolas.magne@icloire.fr [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France)

    2016-04-01

    Introduction: For patients with cervical cancer, intensity-modulated radiation therapy (IMRT) improves target coverage and allows dose escalation while reducing the radiation dose to organs at risk (OARs). In this study, we compared dosimetric parameters among 3-dimensional conformal radiotherapy (3D-CRT), “step-and-shoot” IMRT, and volumetric intensity-modulated arc radiotherapy (VMAT) in a series of patients with cervical cancer receiving definitive radiotherapy. Computed tomography (CT) scans of 10 patients with histologically proven cervical cancer treated with definitive radiation therapy (RT) from December 2008 to March 2010 at our department were selected for this study. The gross tumor volume (GTV) and clinical target volume (CTV) were delineated following the guidelines of the Gyn IMRT consortium that included cervix, uterus, parametrial tissues, and the pelvic nodes including presacral. The median age was 57 years (range: 30 to 85 years). All 10 patients had squamous cell carcinoma with Federation of Gynecology and Obstetrics (FIGO) stage IB-IIIB. All patients were treated by VMAT. OAR doses were significantly reduced for plans with intensity-modulated technique compared with 3D-CRT except for the dose to the vagina. Between the 2 intensity-modulated techniques, significant difference was observed for the mean dose to the small intestine, to the benefit of VMAT (p < 0.001). There was no improvement in terms of OARs sparing for VMAT although there was a tendency for a slightly decreased average dose to the rectum: − 0.65 Gy but not significant (p = 0.07). The intensity modulation techniques have many advantages in terms of quality indexes, and particularly OAR sparing, compared with 3D-CRT. Following the ongoing technologic developments in modern radiotherapy, it is essential to evaluate the intensity-modulated techniques on prospective studies of a larger scale.

  16. Discovery of PI-1840, a novel noncovalent and rapidly reversible proteasome inhibitor with anti-tumor activity.

    Science.gov (United States)

    Kazi, Aslamuzzaman; Ozcan, Sevil; Tecleab, Awet; Sun, Ying; Lawrence, Harshani R; Sebti, Saïd M

    2014-04-25

    The proteasome inhibitor bortezomib is effective in hematologic malignancies such as multiple myeloma but has little activity against solid tumors, acts covalently, and is associated with undesired side effects. Therefore, noncovalent inhibitors that are less toxic and more effective against solid tumors are desirable. Structure activity relationship studies led to the discovery of PI-1840, a potent and selective inhibitor for chymotrypsin-like (CT-L) (IC50 value = 27 ± 0.14 nm) over trypsin-like and peptidylglutamyl peptide hydrolyzing (IC50 values >100 μm) activities of the proteasome. Furthermore, PI-1840 is over 100-fold more selective for the constitutive proteasome over the immunoproteasome. Mass spectrometry and dialysis studies demonstrate that PI-1840 is a noncovalent and rapidly reversible CT-L inhibitor. In intact cancer cells, PI-1840 inhibits CT-L activity, induces the accumulation of proteasome substrates p27, Bax, and IκB-α, inhibits survival pathways and viability, and induces apoptosis. Furthermore, PI-1840 sensitizes human cancer cells to the mdm2/p53 disruptor, nutlin, and to the pan-Bcl-2 antagonist BH3-M6. Finally, in vivo, PI-1840 but not bortezomib suppresses the growth in nude mice of human breast tumor xenografts. These results warrant further evaluation of a noncovalent and rapidly reversible proteasome inhibitor as potential anticancer agents against solid tumors.

  17. Complete inactivation of photosynthetic activity during desiccation and rapid recovery by rehydration in the aerial microalga Trentepohlia jolithus.

    Science.gov (United States)

    Zhang, L; Li, Y; Liu, J

    2016-11-01

    Aerial microalgae are more exposed to harsh and rapidly changing environmental conditions, including desiccation and radiation. Under high light, aerial algae in the desiccated state would be highly subject to photodamage. Therefore, aerial algae need effective protective mechanisms to dissipate excess excitation energy. In this study, the changes in photosynthetic behaviors during desiccation and after rehydration in Trentepohlia jolithus were confirmed using chlorophyll a fluorescence (OJIP) transient, allowing determination of the photoprotection mechanisms of this aerial alga. The filaments of T. jolithus cells at 25% relative air humidity (RH) are significantly shrunken compared with those at 100% and 87% RH, decreasing the surface area for light absorption. At 25% RH, the shape and intensity of the OJIP transient disappeared, but recovered rapidly to the level at 100% RH after 5 s of rehydration. Compared with 100% RH, the maximum quantum yield of PSII (φPo ), phenomenological energy fluxes for absorption (ABS/CSm) and active PSII reaction centers (RCs) at 25% RH decreased significantly, the specific energy fluxes for absorption (ABS/RC) increased significantly, but the specific energy fluxes for trapping (TRo/RC) at 25% RH did not change. These parameters at 25% RH recovered rapidly to the level at 100% RH after 5 s of rehydration. These results suggest that the efficiency of PSII light absorption and activities of PSII RCs were reversibly down-regulated in desiccated T. jolithus, which may be a special adaptive mechanism for the survivability of aerial microalgae in habitats with rapidly changing water availability. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  18. Rapid Response Concentration-Controlled Desorption of Activated Carbon to Dampen Concentration Fluctuations

    Science.gov (United States)

    2007-01-01

    will be much smaller and will sustain a much more stable microbial population because the microorganisms will not experience starvation during times...activated carbon biofilter. Bioprocess Eng. 1997, 16, 331-337. (10) Weber, F. J.; Hartmans, S. Use of activated carbon as a buffer in biofiltration of waste

  19. Rapid and enhanced activation of microporous coordination polymers by flowing supercritical CO.sub.2

    Science.gov (United States)

    Matzger, Adam J.; Liu, Baojian; Wong-Foy, Antek G.

    2016-07-19

    Flowing supercritical CO.sub.2 is used to activate metal organic framework materials (MOF). MOFs are activated directly from N,N-dimethylformamide (DMF) thus avoiding exchange with a volatile solvent. Most MCPs display increased surface areas directly after treatment although those with coordinatively unsaturated metal centers benefit from additional heating.

  20. A mixed population of antagonist and agonist binding conformers in a single crystal explains partial agonism against vitamin D receptor: active vitamin D analogues with 22R-alkyl group.

    Science.gov (United States)

    Anami, Yasuaki; Itoh, Toshimasa; Egawa, Daichi; Yoshimoto, Nobuko; Yamamoto, Keiko

    2014-05-22

    We are continuing to study the structural basis of vitamin D receptor (VDR) agonism and antagonism by using 22S-alkyl vitamin D analogues. Here we report the synthesis and biological evaluation of 22R-alkyl analogues and the X-ray crystallographic analysis of vitamin D receptor ligand-binding domain (VDR-LBD) complexed with a 22R-analogue. VDR-LBD complexed with the partial agonist 8a showed that 8a binds to VDR-LBD with two conformations, one of which is the antagonist/VDR-LBD complex structure and the other is the agonist/VDR-LBD complex structure. The results indicate that the partial agonist activity of 8a depends on the sum of antagonistic and agonistic activities caused by the antagonist and agonist binding conformers, respectively. The structural basis observed here must be applicable to the partial agonism of other ligand-dependent nuclear receptors. This is the first report describing the trapping of a conformational subset of the ligand and the nuclear receptor in a single crystal.

  1. Distance Geometry Protocol to Generate Conformations of Natural Products to Structurally Interpret Ion Mobility-Mass Spectrometry Collision Cross Sections

    Science.gov (United States)

    2015-01-01

    Ion mobility-mass spectrometry (IM-MS) allows the separation of ionized molecules based on their charge-to-surface area (IM) and mass-to-charge ratio (MS), respectively. The IM drift time data that is obtained is used to calculate the ion-neutral collision cross section (CCS) of the ionized molecule with the neutral drift gas, which is directly related to the ion conformation and hence molecular size and shape. Studying the conformational landscape of these ionized molecules computationally provides interpretation to delineate the potential structures that these CCS values could represent, or conversely, structural motifs not consistent with the IM data. A challenge in the IM-MS community is the ability to rapidly compute conformations to interpret natural product data, a class of molecules exhibiting a broad range of biological activity. The diversity of biological activity is, in part, related to the unique structural characteristics often observed for natural products. Contemporary approaches to structurally interpret IM-MS data for peptides and proteins typically utilize molecular dynamics (MD) simulations to sample conformational space. However, MD calculations are computationally expensive, they require a force field that accurately describes the molecule of interest, and there is no simple metric that indicates when sufficient conformational sampling has been achieved. Distance geometry is a computationally inexpensive approach that creates conformations based on sampling different pairwise distances between the atoms within the molecule and therefore does not require a force field. Progressively larger distance bounds can be used in distance geometry calculations, providing in principle a strategy to assess when all plausible conformations have been sampled. Our results suggest that distance geometry is a computationally efficient and potentially superior strategy for conformational analysis of natural products to interpret gas-phase CCS data. PMID:25360896

  2. Field-deployable, quantitative, rapid identification of active Ebola virus infection in unprocessed blood.

    Science.gov (United States)

    Shah, Kavit; Bentley, Emma; Tyler, Adam; Richards, Kevin S R; Wright, Edward; Easterbrook, Linda; Lee, Diane; Cleaver, Claire; Usher, Louise; Burton, Jane E; Pitman, James K; Bruce, Christine B; Edge, David; Lee, Martin; Nazareth, Nelson; Norwood, David A; Moschos, Sterghios A

    2017-11-01

    The West African Ebola virus outbreak underlined the importance of delivering mass diagnostic capability outside the clinical or primary care setting in effectively containing public health emergencies caused by infectious disease. Yet, to date, there is no solution for reliably deploying at the point of need the gold standard diagnostic method, real time quantitative reverse transcription polymerase chain reaction (RT-qPCR), in a laboratory infrastructure-free manner. In this proof of principle work, we demonstrate direct performance of RT-qPCR on fresh blood using far-red fluorophores to resolve fluorogenic signal inhibition and controlled, rapid freeze/thawing to achieve viral genome extraction in a single reaction chamber assay. The resulting process is entirely free of manual or automated sample pre-processing, requires no microfluidics or magnetic/mechanical sample handling and thus utilizes low cost consumables. This enables a fast, laboratory infrastructure-free, minimal risk and simple standard operating procedure suited to frontline, field use. Developing this novel approach on recombinant bacteriophage and recombinant human immunodeficiency virus (HIV; Lentivirus), we demonstrate clinical utility in symptomatic EBOV patient screening using live, infectious Filoviruses and surrogate patient samples. Moreover, we evidence assay co-linearity independent of viral particle structure that may enable viral load quantification through pre-calibration, with no loss of specificity across an 8 log-linear maximum dynamic range. The resulting quantitative rapid identification (QuRapID) molecular diagnostic platform, openly accessible for assay development, meets the requirements of resource-limited countries and provides a fast response solution for mass public health screening against emerging biosecurity threats.

  3. Brain activity-based image classification from rapid serial visual presentation.

    Science.gov (United States)

    Bigdely-Shamlo, Nima; Vankov, Andrey; Ramirez, Rey R; Makeig, Scott

    2008-10-01

    We report the design and performance of a brain-computer interface (BCI) system for real-time single-trial binary classification of viewed images based on participant-specific dynamic brain response signatures in high-density (128-channel) electroencephalographic (EEG) data acquired during a rapid serial visual presentation (RSVP) task. Image clips were selected from a broad area image and presented in rapid succession (12/s) in 4.1-s bursts. Participants indicated by subsequent button press whether or not each burst of images included a target airplane feature. Image clip creation and search path selection were designed to maximize user comfort and maintain user awareness of spatial context. Independent component analysis (ICA) was used to extract a set of independent source time-courses and their minimally-redundant low-dimensional informative features in the time and time-frequency amplitude domains from 128-channel EEG data recorded during clip burst presentations in a training session. The naive Bayes fusion of two Fisher discriminant classifiers, computed from the 100 most discriminative time and time-frequency features, respectively, was used to estimate the likelihood that each clip contained a target feature. This estimator was applied online in a subsequent test session. Across eight training/test session pairs from seven participants, median area under the receiver operator characteristic curve, by tenfold cross validation, was 0.97 for within-session and 0.87 for between-session estimates, and was nearly as high (0.83) for targets presented in bursts that participants mistakenly reported to include no target features.

  4. Conformal Dynamics of Precursors to Fracture

    OpenAIRE

    Barra, Felipe; Herrera, Mauricio; Procaccia, Itamar

    2002-01-01

    An exact integro-differential equation for the conformal map from the unit circle to the boundary of an evolving cavity in a stressed 2-dimensional solid is derived. This equation provides an accurate description of the dynamics of precursors to fracture when surface diffusion is important. The solution predicts the creation of sharp grooves that eventually lead to material failure via rapid fracture. Solutions of the new equation are demonstrated for the dynamics of an elliptical cavity and ...

  5. Rapid Guest Exchange and Ultra-Low Surface Tension Solvents Optimize Metal-Organic Framework Activation.

    Science.gov (United States)

    Ma, Jialiu; Kalenak, Andre P; Wong-Foy, Antek G; Matzger, Adam J

    2017-11-13

    Exploratory research into the critical steps in metal-organic framework (MOF) activation involving solvent exchange and solvent evacuation are reported. It is discovered that solvent exchange kinetics are extremely fast, and minutes rather days are appropriate for solvent exchange in many MOFs. It is also demonstrated that choice of a very low surface tension solvent is critical in successfully activating challenging MOFs. MOFs that have failed to be activated previously can achieve predicted surface areas provided that lower surface tension solvents, such as n-hexane and perfluoropentane, are applied. The insights herein aid in the efficient activation of MOFs in both laboratory and industrial settings and provide best practices for avoiding structural collapse. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Rapid shifts in Atta cephalotes fungus-garden enzyme activity after a change in fungal substrate (Attini, Formicidae)

    DEFF Research Database (Denmark)

    Kooij, P W; Schiøtt, M; Boomsma, J J

    2011-01-01

    Fungus gardens of the basidiomycete Leucocoprinus gongylophorus sustain large colonies of leaf-cutting ants by degrading the plant material collected by the ants. Recent studies have shown that enzyme activity in these gardens is primarily targeted toward starch, proteins and the pectin matrix...... associated with cell walls, rather than toward structural cell wall components such as cellulose and hemicelluloses. Substrate constituents are also known to be sequentially degraded in different sections of the fungus garden. To test the plasticity in the extracellular expression of fungus-garden enzymes......, we measured the changes in enzyme activity after a controlled shift in fungal substrate offered to six laboratory colonies of Atta cephalotes. An ant diet consisting exclusively of grains of parboiled rice rapidly increased the activity of endo-proteinases and some of the pectinases attacking...

  7. The conforming brain and deontological resolve.

    Directory of Open Access Journals (Sweden)

    Melanie Pincus

    Full Text Available Our personal values are subject to forces of social influence. Deontological resolve captures how strongly one relies on absolute rules of right and wrong in the representation of one's personal values and may predict willingness to modify one's values in the presence of social influence. Using fMRI, we found that a neurobiological metric for deontological resolve based on relative activity in the ventrolateral prefrontal cortex (VLPFC during the passive processing of sacred values predicted individual differences in conformity. Individuals with stronger deontological resolve, as measured by greater VLPFC activity, displayed lower levels of conformity. We also tested whether responsiveness to social reward, as measured by ventral striatal activity during social feedback, predicted variability in conformist behavior across individuals but found no significant relationship. From these results we conclude that unwillingness to conform to others' values is associated with a strong neurobiological representation of social rules.

  8. Dissecting the role of conformational change and membrane binding by the bacterial cell division regulator MinE in the stimulation of MinD ATPase activity.

    Science.gov (United States)

    Ayed, Saud H; Cloutier, Adam D; McLeod, Laura J; Foo, Alexander C Y; Damry, Adam M; Goto, Natalie K

    2017-12-15

    The bacterial cell division regulators MinD and MinE together with the division inhibitor MinC localize to the membrane in concentrated zones undergoing coordinated pole-to-pole oscillation to help ensure that the cytokinetic division septum forms only at the mid-cell position. This dynamic localization is driven by MinD-catalyzed ATP hydrolysis, stimulated by interactions with MinE's anti-MinCD domain. This domain is buried in the 6-β-stranded MinE "closed" structure, but is liberated for interactions with MinD, giving rise to a 4-β-stranded "open" structure through an unknown mechanism. Here we show that MinE-membrane interactions induce a structural change into a state resembling the open conformation. However, MinE mutants lacking the MinE membrane-targeting sequence stimulated higher ATP hydrolysis rates than the full-length protein, indicating that binding to MinD is sufficient to trigger this conformational transition in MinE. In contrast, conformational change between the open and closed states did not affect stimulation of ATP hydrolysis rates in the absence of membrane binding, although the MinD-binding residue Ile-25 is critical for this conformational transition. We therefore propose an updated model where MinE is brought to the membrane through interactions with MinD. After stimulation of ATP hydrolysis, MinE remains bound to the membrane in a state that does not catalyze additional rounds of ATP hydrolysis. Although the molecular basis for this inhibited state is unknown, previous observations of higher-order MinE self-association may explain this inhibition. Overall, our findings have general implications for Min protein oscillation cycles, including those that regulate cell division in bacterial pathogens. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Galilean conformal and superconformal symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Lukierski, J., E-mail: lukier@ift.uni.wroc.pl [University of Wroclaw, Institute for Theoretical Physics (Poland)

    2012-10-15

    Firstly we discuss briefly three different algebras named as nonrelativistic (NR) conformal: Schroedinger, Galilean conformal, and infinite algebra of local NR conformal isometries. Further we shall consider in some detail Galilean conformal algebra (GCA) obtained in the limit c{yields}{infinity} from relativistic conformal algebraO(d+1, 2) (d-number of space dimensions). Two different contraction limits providing GCA and some recently considered realizations will be briefly discussed. Finally by considering NR contraction of D = 4 superconformal algebra the Galilei conformal superalgebra (GCSA) is obtained, in the formulation using complexWeyl supercharges.

  10. Children treated for severe acute malnutrition experience a rapid increase in physical activity a few days after admission.

    Science.gov (United States)

    Faurholt-Jepsen, Daniel; Hansen, Kristina Beck; van Hees, Vincent T; Christensen, Line Brinch; Girma, Tsinuel; Friis, Henrik; Brage, Søren

    2014-06-01

    To assess physical activity at admission and during recovery from severe acute malnutrition. Ethiopian children who were admitted with severe acute malnutrition received a clinical examination each week to monitor their recovery during rehabilitation. Using accelerometry (24 h/d for 5 consecutive days) at admission and again after 10 days of rehabilitation, we assessed the level and changes of physical activity. Among 13 children included, the mean (SD) age was 31.1 months (15.5). At baseline, the day-night activity difference was relatively small, whereas the level of activity had substantially increased at follow-up. The diurnal mean acceleration level was significantly greater at follow-up for wrist (1158.8 vs 541.4 counts per minute, P = .003) but not hip movements (204.1 vs 141.5, P = .261). During daytime (6 a.m. to 10 p.m.), hip activity increased by 38% from baseline to follow-up (e(B) 1.38, 95% CI 1.17-1.62), and wrist activity more than doubled (e(B) 2.50, 95% CI 2.17-2.87). The level of physical activity among children with severe acute malnutrition is very low but increases rapidly during recovery. Accelerometry may be a useful approach in the recovery phase as an indicator of early improvement. Copyright © 2014 The Authors. Published by Mosby, Inc. All rights reserved.

  11. The research of conformal optical design

    Science.gov (United States)

    Li, Lin; Li, Yan; Huang, Yi-fan; Du, Bao-lin

    2009-07-01

    in conformal optical design, the SPGD optimization algorithm is operated at each zoom position to calculate the optimized surface shape of the MEMS DM. The communication between MATLAB and Code V established via ActiveX technique is applied in simulation analysis.

  12. One-step and rapid synthesis of porous Pd nanoparticles with superior catalytic activity toward ethanol/formic acid electrooxidation

    Science.gov (United States)

    Hong, Wei; Fang, Youxing; Wang, Jin; Wang, Erkang

    2014-02-01

    Porous Pd nanoparticles are successfully prepared by a rapid, one-step, and efficient route with high yield in aqueous solution. The developed method is very simple, just by mixing sodium tetrachloropalladate, polyvinylpyrrolidone and hydroquinone and heated at 70 °C for 15 min. The structure and composition are analyzed by transmission electron microscope, selected-area electron diffraction, inductively coupled plasma optical emission spectrometer, X-ray diffraction, energy dispersive X-ray spectrum and X-ray photoelectron spectroscopy. Electrochemical catalytic measurement results prove that the as synthesized porous Pd nanoparticles exhibit superior catalytic activity towards ethanol and formic acid electrooxidation.

  13. Steam-cooking rapidly destroys and reverses onion-induced antiplatelet activity.

    Science.gov (United States)

    Hansen, Emilie A; Folts, John D; Goldman, Irwin L

    2012-09-20

    Foods in the diet that can aid in the prevention of diseases are of major interest. Onions are key ingredients in many cuisines around the world and moreover, onion demand has trended higher over the past three decades. An important pharmacological aspect of onion is the ability to inhibit platelet aggregation. Raw onions inhibit platelet aggregation; however, when onions are boiled or heated, antiplatelet activity may be abolished. Onion quarters were steamed for 0, 1, 3, 6, 10, and 15 min. The in vitro antiplatelet activity of a yellow hybrid storage onion was examined at these times on the blood of 12 human subjects using in vitro whole blood aggregometry. Contrary to findings reported for boiling, antiplatelet activity was destroyed between 3 and 6 min of steaming, and at 10 min of steaming, cooked onions stimulated platelet activity. Extracts from cooked onion had the potential to reverse the inhibitory effect on blood platelets by 25%. Responses were consistent across all donors. Total polyphenolic concentration and soluble solids were not affected by steaming time. The potential value of cooked onion preparations may result in destruction or reversal of antiplatelet activity, without affecting the polyphenolic concentration.

  14. Steam-cooking rapidly destroys and reverses onion-induced antiplatelet activity

    Science.gov (United States)

    2012-01-01

    Background Foods in the diet that can aid in the prevention of diseases are of major interest. Onions are key ingredients in many cuisines around the world and moreover, onion demand has trended higher over the past three decades. An important pharmacological aspect of onion is the ability to inhibit platelet aggregation. Raw onions inhibit platelet aggregation; however, when onions are boiled or heated, antiplatelet activity may be abolished. Methods Onion quarters were steamed for 0, 1, 3, 6, 10, and 15 min. The in vitro antiplatelet activity of a yellow hybrid storage onion was examined at these times on the blood of 12 human subjects using in vitro whole blood aggregometry. Results Contrary to findings reported for boiling, antiplatelet activity was destroyed between 3 and 6 min of steaming, and at 10 min of steaming, cooked onions stimulated platelet activity. Extracts from cooked onion had the potential to reverse the inhibitory effect on blood platelets by 25%. Responses were consistent across all donors. Total polyphenolic concentration and soluble solids were not affected by steaming time. Conclusions The potential value of cooked onion preparations may result in destruction or reversal of antiplatelet activity, without affecting the polyphenolic concentration. PMID:22992282

  15. Steam-cooking rapidly destroys and reverses onion-induced antiplatelet activity

    Directory of Open Access Journals (Sweden)

    Hansen Emilie A

    2012-09-01

    Full Text Available Abstract Background Foods in the diet that can aid in the prevention of diseases are of major interest. Onions are key ingredients in many cuisines around the world and moreover, onion demand has trended higher over the past three decades. An important pharmacological aspect of onion is the ability to inhibit platelet aggregation. Raw onions inhibit platelet aggregation; however, when onions are boiled or heated, antiplatelet activity may be abolished. Methods Onion quarters were steamed for 0, 1, 3, 6, 10, and 15 min. The in vitro antiplatelet activity of a yellow hybrid storage onion was examined at these times on the blood of 12 human subjects using in vitro whole blood aggregometry. Results Contrary to findings reported for boiling, antiplatelet activity was destroyed between 3 and 6 min of steaming, and at 10 min of steaming, cooked onions stimulated platelet activity. Extracts from cooked onion had the potential to reverse the inhibitory effect on blood platelets by 25%. Responses were consistent across all donors. Total polyphenolic concentration and soluble solids were not affected by steaming time. Conclusions The potential value of cooked onion preparations may result in destruction or reversal of antiplatelet activity, without affecting the polyphenolic concentration.

  16. Muscle size, neuromuscular activation, and rapid force characteristics in elderly men and women

    DEFF Research Database (Denmark)

    Suetta, C; Aagaard, P; Magnusson, S P

    2007-01-01

    Substantial evidence exists for the age-related decline in muscle strength and neural function, but the effect of long-term disuse in the elderly is largely unexplored. The present study examined the effect of unilateral long-term limb disuse on maximal voluntary quadriceps contraction (MVC), lean......%), contractile RFD (W: 17-26%; M: 15-24%), impulse (W: 10-19%, M: 19-20%), maximal EMG amplitude (W: 22-25%, M: 22-28%), and an increased muscle activation deficit (-18%) compared with UN. Furthermore, women were less strong (AF: 40%; UN: 39%), had less muscle mass (AF: 33%; UN: 34%), and had a lower RFD (AF: 38...... quadriceps muscle cross-sectional area (LCSA), contractile rate of force development (RFD, Delta force/Delta time), impulse (integral force dt), muscle activation deficit (interpolated twitch technique), maximal neuromuscular activity [electromyogram (EMG)], and antagonist muscle coactivation in elderly men...

  17. Rapid regulation of sialidase activity in response to neural activity and sialic acid removal during memory processing in rat hippocampus.

    Science.gov (United States)

    Minami, Akira; Meguro, Yuko; Ishibashi, Sayaka; Ishii, Ami; Shiratori, Mako; Sai, Saki; Horii, Yuuki; Shimizu, Hirotaka; Fukumoto, Hokuto; Shimba, Sumika; Taguchi, Risa; Takahashi, Tadanobu; Otsubo, Tadamune; Ikeda, Kiyoshi; Suzuki, Takashi

    2017-04-07

    Sialidase cleaves sialic acids on the extracellular cell surface as well as inside the cell and is necessary for normal long-term potentiation (LTP) at mossy fiber-CA3 pyramidal cell synapses and for hippocampus-dependent spatial memory. Here, we investigated in detail the role of sialidase in memory processing. Sialidase activity measured with 4-methylumbelliferyl-α-d-N-acetylneuraminic acid (4MU-Neu5Ac) or 5-bromo-4-chloroindol-3-yl-α-d-N-acetylneuraminic acid (X-Neu5Ac) and Fast Red Violet LB was increased by high-K+-induced membrane depolarization. Sialidase activity was also increased by chemical LTP induction with forskolin and activation of BDNF signaling, non-NMDA receptors, or NMDA receptors. The increase in sialidase activity with neural excitation appears to be caused not by secreted sialidase or by an increase in sialidase expression but by a change in the subcellular localization of sialidase. Astrocytes as well as neurons are also involved in the neural activity-dependent increase in sialidase activity. Sialidase activity visualized with a benzothiazolylphenol-based sialic acid derivative (BTP3-Neu5Ac), a highly sensitive histochemical imaging probe for sialidase activity, at the CA3 stratum lucidum of rat acute hippocampal slices was immediately increased in response to LTP-inducible high-frequency stimulation on a time scale of seconds. To obtain direct evidence for sialic acid removal on the extracellular cell surface during neural excitation, the extracellular free sialic acid level in the hippocampus was monitored using in vivo microdialysis. The free sialic acid level was increased by high-K+-induced membrane depolarization. Desialylation also occurred during hippocampus-dependent memory formation in a contextual fear-conditioning paradigm. Our results show that neural activity-dependent desialylation by sialidase may be involved in hippocampal memory processing. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. RAPID KNEE-EXTENSIONS TO INCREASE QUADRICEPS MUSCLE ACTIVITY IN PATIENTS WITH TOTAL KNEE ARTHROPLASTY

    DEFF Research Database (Denmark)

    Husted, Rasmus Skov; Wilquin, Lousia; Jakobsen, Thomas Linding

    2017-01-01

    BACKGROUND: Inhibition of the quadriceps muscle and reduced knee-extension strength is common shortly following total knee arthroplasty (weeks to months), due to reduced voluntary activation of the quadriceps muscle. In healthy subjects, strength training with heavy loads is known to increase ago...

  19. Rapid knee-extensions to increase quadriceps muscle activity in patients with total knee arthroplasty

    DEFF Research Database (Denmark)

    Husted, Rasmus Skov; Wilquin, Lousia; Jakobsen, Thomas Linding

    2017-01-01

    BACKGROUND: Inhibition of the quadriceps muscle and reduced knee-extension strength is common shortly following total knee arthroplasty (weeks to months), due to reduced voluntary activation of the quadriceps muscle. In healthy subjects, strength training with heavy loads is known to increase ago...

  20. Rapid NK-cell activation in chicken after infection with infectious bronchitis virus M41

    NARCIS (Netherlands)

    Vervelde, L.; Matthijs, M.G.R.; van Haarlem, D.A.; de Wit, Sjaak; Jansen, C.A.

    2013-01-01

    Natural killer (NK) cells are cytotoxic lymphocytes and play an important role in the early defence against viruses. In this study we focussed on NK cell and interferon (IFN) responses after infection with infectious bronchitis virus (IBV). Based on surface expression of CD107+, enhanced activation

  1. Rapid and reliable determination of the halogenating peroxidase activity in blood samples.

    Science.gov (United States)

    Flemmig, Jörg; Schwarz, Pauline; Bäcker, Ingo; Leichsenring, Anna; Lange, Franziska; Arnhold, Jürgen

    2014-12-15

    By combining easy and fast leukocyte enrichment with aminophenyl-fluorescein (APF) staining we developed a method to quickly and specifically address the halogenating activity of the immunological relevant blood heme peroxidases myeloperoxidase and eosinophil peroxidase, respectively. For leukocyte enrichment a two-fold hypotonic lysis procedure of the blood with Millipore water was chosen which represents a cheap, fast and reliable method to diminish the amount of erythrocytes in the samples. This procedure is shown to be suitable both to human and murine blood micro-samples, making it also applicable to small animal experiments with recurring blood sampling. As all types of leukocytes are kept in the sample during the preparation, they can be analysed separately after discrimination during the flow cytometry analysis. This also holds for all heme peroxidase-containing cells, namely neutrophils, eosinophils and monocytes. Moreover additional parameters (e.g. antibody staining) can be combined with the heme peroxidase activity determination to gain additional information about the different immune cell types. Based on previous results we applied APF for specifically addressing the halogenating activity of leukocyte peroxidases in blood samples. This dye is selectively oxidized by the MPO and EPO halogenation products hypochlorous and hypobromous acid. This approach may provide a suitable tool to gain more insights into the immune-physiological role of the halogenating activity of heme peroxidases. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. TNF as biomarker for rapid quantification of active Staphylococcus enterotoxin A in food

    Science.gov (United States)

    Staphylococcus aureus is a major bacterial pathogen which causes clinical infection and food poisoning. This bacterium produces a group of twenty-one enterotoxins (SEs). These enterotoxins have two separate but related biological activities. They cause gastroenteritis and function as superantigens t...

  3. Transportation Conformity Training and Presentations

    Science.gov (United States)

    EPA's OTAQ has provided multiple conformity training sessions in the past to assist state and local governments in implementing conformity requirements. As training information is prepared for other venues, it will be posted on this page.

  4. Dynamical spacetimes in conformal gravity

    National Research Council Canada - National Science Library

    Hongsheng Zhang; Yi Zhang; Xin-Zhou Li

    2017-01-01

    The conformal gravity remarkably boosts our prehension of gravity theories. We find a series of dynamical solutions in the W2-conformal gravity, including generalized Schwarzschild–Friedmann–Robertson–Walker (GSFRW...

  5. A Rapid and Quantitative Flow Cytometry Method for the Analysis of Membrane Disruptive Antimicrobial Activity.

    Directory of Open Access Journals (Sweden)

    Neil M O'Brien-Simpson

    Full Text Available We describe a microbial flow cytometry method that quantifies within 3 hours antimicrobial peptide (AMP activity, termed Minimum Membrane Disruptive Concentration (MDC. Increasing peptide concentration positively correlates with the extent of bacterial membrane disruption and the calculated MDC is equivalent to its MBC. The activity of AMPs representing three different membranolytic modes of action could be determined for a range of Gram positive and negative bacteria, including the ESKAPE pathogens, E. coli and MRSA. By using the MDC50 concentration of the parent AMP, the method provides high-throughput, quantitative screening of AMP analogues. A unique feature of the MDC assay is that it directly measures peptide/bacteria interactions and lysed cell numbers rather than bacteria survival as with MIC and MBC assays. With the threat of multi-drug resistant bacteria, this high-throughput MDC assay has the potential to aid in the development of novel antimicrobials that target bacteria with improved efficacy.

  6. Brain activity during bilateral rapid alternate finger tapping measured with magnetoencephalography

    Science.gov (United States)

    Fukuda, Hiroshi; Odagaki, Masato; Hiwaki, Osamu; Kodabashi, Atsushi; Fujimoto, Toshiro

    2009-04-01

    Using magnetoencephalography (MEG), brain regions involved in an alternate bimanual tapping task by index fingers triggered with spontaneous timing were investigated. The tapping mode in which both index fingers moved simultaneously was interlaced during the task. The groups of the alternate tapping (AL mode) and the simultaneous tapping (SI mode) were extracted from the successive alternating taps with a histogram of intervals between the right and left index fingers. MEG signals in each mode were averaged separately before and after the tapping initiation of the dominant index finger. The activities of the contralateral sensorimotor cortex before and after the tapping initiation in the AL mode were larger than that in the SI mode. The result indicates that the activity of the contralateral sensorimotor cortex depends on the degree of achievement in the difficult motor task such as the voluntary alternate tapping movements.

  7. Rapidly light-activated surgical protein glue inspired by mussel adhesion and insect structural crosslinking.

    Science.gov (United States)

    Jeon, Eun Young; Hwang, Byeong Hee; Yang, Yun Jung; Kim, Bum Jin; Choi, Bong-Hyuk; Jung, Gyu Yong; Cha, Hyung Joon

    2015-10-01

    Currently approved surgical tissue glues do not satisfy the requirements for ideal bioadhesives due to limited adhesion in wet conditions and severe cytotoxicity. Herein, we report a new light-activated, mussel protein-based bioadhesive (LAMBA) inspired by mussel adhesion and insect dityrosine crosslinking chemistry. LAMBA exhibited substantially stronger bulk wet tissue adhesion than commercially available fibrin glue and good biocompatibility in both in vitro and in vivo studies. Besides, the easily tunable, light-activated crosslinking enabled an effective on-demand wound closure and facilitated wound healing. Based on these outstanding properties, LAMBA holds great potential as an ideal surgical tissue glue for diverse medical applications, including sutureless wound closures of skin and internal organs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Steam-cooking rapidly destroys and reverses onion-induced antiplatelet activity

    OpenAIRE

    Hansen Emilie A; Folts John D; Goldman Irwin L

    2012-01-01

    Abstract Background Foods in the diet that can aid in the prevention of diseases are of major interest. Onions are key ingredients in many cuisines around the world and moreover, onion demand has trended higher over the past three decades. An important pharmacological aspect of onion is the ability to inhibit platelet aggregation. Raw onions inhibit platelet aggregation; however, when onions are boiled or heated, antiplatelet activity may be abolished. Methods Onion quarters were steamed for ...

  9. Rapid determination of filamentous microorganisms in activated sludge; Determinacion rapida de microorganismos filamentosos en fangos activados

    Energy Technology Data Exchange (ETDEWEB)

    Arnaiz, C.; Jimenez, C.; Estevez, F. [Empresa Municipal de Abastecimiento y Saneamiento de Aguas de Sevilla (Spain)

    1999-07-01

    Despite many methods available biomass estimation of a bioprocess may sometimes become laborious and impracticable. Samples containing filamentous organisms, as in Wastewater Treatment Plants, present special counting difficulties. If they are abundant they may need to be estimated separately. In this work a counting method for these organisms is show. The main goal is to improve chlorination of activated sludge suffering bulking or foaming through a quantitative record of filamentous bacteria. (Author) 12 refs.

  10. Noradrenergic modulation of masseter muscle activity during natural rapid eye movement sleep requires glutamatergic signalling at the trigeminal motor nucleus

    Science.gov (United States)

    Schwarz, Peter B; Mir, Saba; Peever, John H

    2014-01-01

    Noradrenergic neurotransmission in the brainstem is closely coupled to changes in muscle activity across the sleep–wake cycle, and noradrenaline is considered to be a key excitatory neuromodulator that reinforces the arousal-related stimulus on motoneurons to drive movement. However, it is unknown if α-1 noradrenoceptor activation increases motoneuron responsiveness to excitatory glutamate (AMPA) receptor-mediated inputs during natural behaviour. We studied the effects of noradrenaline on AMPA receptor-mediated motor activity at the motoneuron level in freely behaving rats, particularly during rapid eye movement (REM) sleep, a period during which both AMPA receptor-triggered muscle twitches and periods of muscle quiescence in which AMPA drive is silent are exhibited. Male rats were subjected to electromyography and electroencephalography recording to monitor sleep and waking behaviour. The implantation of a cannula into the trigeminal motor nucleus of the brainstem allowed us to perfuse noradrenergic and glutamatergic drugs by reverse microdialysis, and thus to use masseter muscle activity as an index of motoneuronal output. We found that endogenous excitation of both α-1 noradrenoceptor and AMPA receptors during waking are coupled to motor activity; however, REM sleep exhibits an absence of endogenous α-1 noradrenoceptor activity. Importantly, exogenous α-1 noradrenoceptor stimulation cannot reverse the muscle twitch suppression induced by AMPA receptor blockade and nor can it elevate muscle activity during quiet REM, a phase when endogenous AMPA receptor activity is subthreshold. We conclude that the presence of an endogenous glutamatergic drive is necessary for noradrenaline to trigger muscle activity at the level of the motoneuron in an animal behaving naturally. PMID:24860176

  11. Rapid and Quantitative Assay of Amyloid-Seeding Activity in Human Brains Affected with Prion Diseases.

    Directory of Open Access Journals (Sweden)

    Hanae Takatsuki

    Full Text Available The infectious agents of the transmissible spongiform encephalopathies are composed of amyloidogenic prion protein, PrPSc. Real-time quaking-induced conversion can amplify very small amounts of PrPSc seeds in tissues/body fluids of patients or animals. Using this in vitro PrP-amyloid amplification assay, we quantitated the seeding activity of affected human brains. End-point assay using serially diluted brain homogenates of sporadic Creutzfeldt-Jakob disease patients demonstrated that 50% seeding dose (SD50 is reached approximately 10(10/g brain (values varies 10(8.79-10.63/g. A genetic case (GSS-P102L yielded a similar level of seeding activity in an autopsy brain sample. The range of PrPSc concentrations in the samples, determined by dot-blot assay, was 0.6-5.4 μg/g brain; therefore, we estimated that 1 SD50 unit was equivalent to 0.06-0.27 fg of PrPSc. The SD50 values of the affected brains dropped more than three orders of magnitude after autoclaving at 121°C. This new method for quantitation of human prion activity provides a new way to reduce the risk of iatrogenic prion transmission.

  12. Enhanced Activity of Supported Ni Catalysts Promoted by Pt for Rapid Reduction of Aromatic Nitro Compounds

    Directory of Open Access Journals (Sweden)

    Huishan Shang

    2016-06-01

    Full Text Available To improve the activities of non-noble metal catalysts is highly desirable and valuable to the reduced use of noble metal resources. In this work, the supported nickel (Ni and nickel-platinum (NiPt nanocatalysts were derived from a layered double hydroxide/carbon composite precursor. The catalysts were characterized and the role of Pt was analysed using X-ray diffraction (XRD, high-resolution transmission electron microscopy (HRTEM, energy dispersive X-ray spectroscopy (EDS mapping, and X-ray photoelectron spectroscopy (XPS techniques. The Ni2+ was reduced to metallic Ni0 via a self-reduction way utilizing the carbon as a reducing agent. The average sizes of the Ni particles in the NiPt catalysts were smaller than that in the supported Ni catalyst. The electronic structure of Ni was affected by the incorporation of Pt. The optimal NiPt catalysts exhibited remarkably improved activity toward the reduction of nitrophenol, which has an apparent rate constant (Ka of 18.82 × 10−3 s−1, 6.2 times larger than that of Ni catalyst and also larger than most of the reported values of noble-metal and bimetallic catalysts. The enhanced activity could be ascribed to the modification to the electronic structure of Ni by Pt and the effect of exposed crystal planes.

  13. Phasic dopamine release drives rapid activation of striatal D2-receptors

    Science.gov (United States)

    Marcott, Pamela F; Mamaligas, Aphroditi A; Ford, Christopher P

    2014-01-01

    Summary Striatal dopamine transmission underlies numerous goal-directed behaviors. Medium spiny neurons (MSNs) are a major target of dopamine in the striatum. However, as dopamine does not directly evoke a synaptic event in MSNs, the time course of dopamine signaling in these cells remains unclear. To examine how dopamine release activates D2-receptors on MSNs, G-protein activated inwardly rectifying potassium (GIRK2; Kir 3.2) channels were virally overexpressed in the striatum and the resulting outward currents were used as a sensor of D2-receptor activation. Electrical and optogenetic stimulation of dopamine terminals evoked robust D2-receptor inhibitory post-synaptic currents (IPSCs) in GIRK2-expressing MSNs that occurred in under a second. Evoked D2-IPSCs could be driven by repetitive stimulation and were not occluded by background dopamine tone. Together, the results indicate that D2-receptors on MSNs exhibit functional low affinity and suggest that striatal D2-receptors can encode both tonic and phasic dopamine signals. PMID:25242218

  14. Multiscale conformal pattern transfer

    Science.gov (United States)

    Lodewijks, Kristof; Miljkovic, Vladimir; Massiot, Inès; Mekonnen, Addis; Verre, Ruggero; Olsson, Eva; Dmitriev, Alexandre

    2016-06-01

    We demonstrate a method for seamless transfer from a parent flat substrate of basically any lithographic top-down or bottom-up pattern onto essentially any kind of surface. The nano- or microscale patterns, spanning macroscopic surface areas, can be transferred with high conformity onto a large variety of surfaces when such patterns are produced on a thin carbon film, grown on top of a sacrificial layer. The latter allows lifting the patterns from the flat parent substrate onto a water-air interface to be picked up by the host surface of choice. We illustrate the power of this technique by functionalizing broad range of materials including glass, plastics, metals, rough semiconductors and polymers, highlighting the potential applications in in situ colorimetry of the chemistry of materials, anti-counterfeit technologies, biomolecular and biomedical studies, light-matter interactions at the nanoscale, conformal photovoltaics and flexible electronics.

  15. Multiscale conformal pattern transfer.

    Science.gov (United States)

    Lodewijks, Kristof; Miljkovic, Vladimir; Massiot, Inès; Mekonnen, Addis; Verre, Ruggero; Olsson, Eva; Dmitriev, Alexandre

    2016-06-22

    We demonstrate a method for seamless transfer from a parent flat substrate of basically any lithographic top-down or bottom-up pattern onto essentially any kind of surface. The nano- or microscale patterns, spanning macroscopic surface areas, can be transferred with high conformity onto a large variety of surfaces when such patterns are produced on a thin carbon film, grown on top of a sacrificial layer. The latter allows lifting the patterns from the flat parent substrate onto a water-air interface to be picked up by the host surface of choice. We illustrate the power of this technique by functionalizing broad range of materials including glass, plastics, metals, rough semiconductors and polymers, highlighting the potential applications in in situ colorimetry of the chemistry of materials, anti-counterfeit technologies, biomolecular and biomedical studies, light-matter interactions at the nanoscale, conformal photovoltaics and flexible electronics.

  16. Rapid and Sensitive Detection of Breast Cancer Cells in Patient Blood with Nuclease-Activated Probe Technology

    Directory of Open Access Journals (Sweden)

    Sven Kruspe

    2017-09-01

    Full Text Available A challenge for circulating tumor cell (CTC-based diagnostics is the development of simple and inexpensive methods that reliably detect the diverse cells that make up CTCs. CTC-derived nucleases are one category of proteins that could be exploited to meet this challenge. Advantages of nucleases as CTC biomarkers include: (1 their elevated expression in many cancer cells, including cells implicated in metastasis that have undergone epithelial-to-mesenchymal transition; and (2 their enzymatic activity, which can be exploited for signal amplification in detection methods. Here, we describe a diagnostic assay based on quenched fluorescent nucleic acid probes that detect breast cancer CTCs via their nuclease activity. This assay exhibited robust performance in distinguishing breast cancer patients from healthy controls, and it is rapid, inexpensive, and easy to implement in most clinical labs. Given its broad applicability, this technology has the potential to have a substantive impact on the diagnosis and treatment of many cancers.

  17. Flexible and Adhesive Surface Enhance Raman Scattering Active Tape for Rapid Detection of Pesticide Residues in Fruits and Vegetables.

    Science.gov (United States)

    Chen, Jiaming; Huang, Youju; Kannan, Palanisamy; Zhang, Lei; Lin, Zhenyu; Zhang, Jiawei; Chen, Tao; Guo, Longhua

    2016-02-16

    The efficient extraction of targets from complex surfaces is vital for technological applications ranging from environmental pollutant monitoring to analysis of explosive traces and pesticide residues. In our present study, we proposed a proof-of-concept surface enhance Raman scattering (SERS) active substrate serving directly to the rapid extraction and detection of target molecules. The novel substrate was constructed by decorating the commercial tape with colloidal gold nanoparticles (Au NPs), which simultaneously provides SERS activity and "sticky" of adhesive. The utility of SERS tape was demonstrated by directly extracting pesticide residues in fruits and vegetables via a simple and viable "paste and peel off" approach. The obtained strong and easily distinguishable SERS signals allow us to detect various pesticide residues such as parathion-methyl, thiram, and chlorpyrifos in the real samples with complex surfaces including green vegetable, cucumber, orange, and apple.

  18. A comparative study of methods for automatic detection of rapid eye movement abnormal muscular activity in narcolepsy

    DEFF Research Database (Denmark)

    Olesen, Alexander Neergaard; Cesari, Matteo; Christensen, Julie Anja Engelhard

    2018-01-01

    Objective: To evaluate rapid eye movement (REM) muscular activity in narcolepsy by applying five algorithms to electromyogram (EMG) recordings, and to investigate its value for narcolepsy diagnosis. Patients/methods: A modified version of phasic EMG metric (mPEM), muscle activity index (MAI), REM...... atonia index (RAI), supra-threshold REM EMG activit ymetric (STREAM), and Frandsen method (FR) were calculated from polysomnography recordings of 20 healthy controls, 18 clinic controls (subjects suspected with narcolepsy but finally diagnosed without any sleep abnormality), 16 narcolepsy type 1 without...... REM sleep behavior disorder (RBD), 9 narcolepsy type 1 with RBD, and 18 narcolepsy type 2. Diagnostic value of metrics in differentiating between groups was quantified by area under the receiver operating characteristic curve (AUC). Correlations among the metrics and cerebrospinal fluid hypocretin-1...

  19. Antiarrhythmic properties of a rapid delayed-rectifier current activator in rabbit models of acquired long QT syndrome

    DEFF Research Database (Denmark)

    Diness, Thomas G; Yeh, Yung-Hsin; Qi, Xiao Yan

    2008-01-01

    effect of a novel compound (NS1643) that activates the rapid delayed-rectifier K+ current, I(Kr), in two rabbit models of acquired LQTS. METHODS AND RESULTS: We used two clinically relevant in vivo rabbit models of TdP in which we infused NS1643 or vehicle: (i) three-week atrioventricular block...... with ventricular bradypacing; (ii) dofetilide-induced I(Kr) inhibition in methoxamine-sensitized rabbits. In addition, we studied effects on ionic currents in cardiomyocytes with I(Kr) suppressed by bradycardia remodelling or dofetilide exposure. Bradypaced rabbits developed QT interval prolongation, spontaneous...... ventricular ectopy, and TdP. Infusion of NS1643 completely suppressed arrhythmic activity and shortened the QT interval; vehicle had no effect. NS1643 also suppressed ventricular tachyarrhythmias caused by infusion of dofetilide to methoxamine-sensitized rabbits, and reversed dofetilide-induced QT...

  20. Conformal boundaries of warped products

    DEFF Research Database (Denmark)

    Kokkendorff, Simon Lyngby

    2006-01-01

    In this note we prove a result on how to determine the conformal boundary of a type of warped product of two length spaces in terms of the individual conformal boundaries. In the situation, that we treat, the warping and conformal distortion functions are functions of distance to a base point....... The result is applied to produce examples of CAT(0)-spaces, where the conformal and ideal boundaries differ in interesting ways....

  1. Rapid behavioural gregarization in the desert locust, Schistocerca gregaria entails synchronous changes in both activity and attraction to conspecifics.

    Science.gov (United States)

    Rogers, Stephen M; Cullen, Darron A; Anstey, Michael L; Burrows, Malcolm; Despland, Emma; Dodgson, Tim; Matheson, Tom; Ott, Swidbert R; Stettin, Katja; Sword, Gregory A; Simpson, Stephen J

    2014-06-01

    Desert Locusts can change reversibly between solitarious and gregarious phases, which differ considerably in behaviour, morphology and physiology. The two phases show many behavioural differences including both overall levels of activity and the degree to which they are attracted or repulsed by conspecifics. Solitarious locusts perform infrequent bouts of locomotion characterised by a slow walking pace, groom infrequently and actively avoid other locusts. Gregarious locusts are highly active with a rapid walking pace, groom frequently and are attracted to conspecifics forming cohesive migratory bands as nymphs and/or flying swarms as adults. The sole factor driving the onset of gregarization is the presence of conspecifics. In several previous studies concerned with the mechanism underlying this transformation we have used an aggregate measure of behavioural phase state, Pgreg, derived from logistic regression analysis, which combines and weights several behavioural variables to characterise solitarious and gregarious behaviour. Using this approach we have analysed the time course of behavioural change, the stimuli that induce gregarization and the key role of serotonin in mediating the transformation. Following a recent critique that suggested that using Pgreg may confound changes in general activity with genuine gregarization we have performed a meta-analysis examining the time course of change in the individual behaviours that we use to generate Pgreg. We show that the forced crowding of solitarious locusts, tactile stimulation of the hind femora, and the short-term application of serotonin each induce concerted changes in not only locomotion-related variables but also grooming frequency and attraction to other locusts towards those characteristic of long-term gregarious locusts. This extensive meta-analysis supports and extends our previous conclusions that solitarious locusts undergo a rapid behavioural gregarization upon receiving appropriate stimulation for

  2. Rapid behavioural gregarization in the desert locust, Schistocerca gregaria entails synchronous changes in both activity and attraction to conspecifics

    Science.gov (United States)

    Rogers, Stephen M.; Cullen, Darron A.; Anstey, Michael L.; Burrows, Malcolm; Despland, Emma; Dodgson, Tim; Matheson, Tom; Ott, Swidbert R.; Stettin, Katja; Sword, Gregory A.; Simpson, Stephen J.

    2014-01-01

    Desert Locusts can change reversibly between solitarious and gregarious phases, which differ considerably in behaviour, morphology and physiology. The two phases show many behavioural differences including both overall levels of activity and the degree to which they are attracted or repulsed by conspecifics. Solitarious locusts perform infrequent bouts of locomotion characterised by a slow walking pace, groom infrequently and actively avoid other locusts. Gregarious locusts are highly active with a rapid walking pace, groom frequently and are attracted to conspecifics forming cohesive migratory bands as nymphs and/or flying swarms as adults. The sole factor driving the onset of gregarization is the presence of conspecifics. In several previous studies concerned with the mechanism underlying this transformation we have used an aggregate measure of behavioural phase state, Pgreg, derived from logistic regression analysis, which combines and weights several behavioural variables to characterise solitarious and gregarious behaviour. Using this approach we have analysed the time course of behavioural change, the stimuli that induce gregarization and the key role of serotonin in mediating the transformation. Following a recent critique that suggested that using Pgreg may confound changes in general activity with genuine gregarization we have performed a meta-analysis examining the time course of change in the individual behaviours that we use to generate Pgreg. We show that the forced crowding of solitarious locusts, tactile stimulation of the hind femora, and the short-term application of serotonin each induce concerted changes in not only locomotion-related variables but also grooming frequency and attraction to other locusts towards those characteristic of long-term gregarious locusts. This extensive meta-analysis supports and extends our previous conclusions that solitarious locusts undergo a rapid behavioural gregarization upon receiving appropriate stimulation for

  3. Conformal block study and bounding OPE in conformal field theories

    CERN Document Server

    Yvernay, Pierre

    2015-01-01

    During the past few years, the re-emergence of conformal bootstrap as a numerical tool to solve conformal field theory allowed more precise estimation of several presumed conformal field theory among which we could cite the 3D Ising model. This work intends to provide insight on conformal blocks which are elementary objects in the conformal bootstrap approach. These are considered in Euclidian space where we study fields of all equal dimension. This study allows us to improve bounds derived in \\cite{OPEconv}.

  4. Polymer Conformation under Confinement

    Directory of Open Access Journals (Sweden)

    Stavros Bollas

    2017-02-01

    Full Text Available The conformation of polymer chains under confinement is investigated in intercalated polymer/layered silicate nanocomposites. Hydrophilic poly(ethylene oxide/sodium montmorillonite, PEO/Na+-MMT, hybrids were prepared utilizing melt intercalation with compositions where the polymer chains are mostly within the ~1 nm galleries of the inorganic material. The polymer chains are completely amorphous in all compositions even at temperatures where the bulk polymer is highly crystalline. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR is utilized to investigate the conformation of the polymer chains over a broad range of temperatures from below to much higher than the bulk polymer melting temperature. A systematic increase of the gauche conformation relatively to the trans is found with decreasing polymer content both for the C–C and the C–O bonds that exist along the PEO backbone indicating that the severe confinement and the proximity to the inorganic surfaces results in a more disordered state of the polymer.

  5. Bisphenol A induces a rapid activation of Erk1/2 through GPR30 in human breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Dong, S. [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566 (Japan); Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); Terasaka, S. [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566 (Japan); Kiyama, R., E-mail: kiyama.r@aist.go.j [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566 (Japan)

    2011-01-15

    Bisphenol A (BPA) has been considered as an endocrine disruptor due to its ability to interact with estrogen receptors (ERs). While G protein-coupled receptor 30 (GPR30) is a novel estrogen receptor, its role in BPA-induced activation of Erk1/2 remains unknown. Human breast cancer cell lines, MCF-7, MDA-MB-231 and SKBR3, were used as experimental models to discriminate between ERs-dependent, putative ERs-independent and/or GPR30-associated effects. BPA induced a rapid activation of Erk1/2 in both ER{alpha}/{beta}-positive and negative breast cancer cells, and this effect was not blocked with an ER antagonist, ICI 182,780. A small interfering RNA assay revealed that the expression of GPR30 was necessary for BPA-induced activation of Erk1/2 and transcriptional regulation of c-fos. In addition, BPA regulates the expression of c-fos likely through an AP1-mediated pathway. As a conclusion, GPR30 plays an important role in the BPA-induced activation of Erk1/2 in a manner distinguishable from that in ER{alpha}-mediated signaling. - We showed here that the mechanism by which BPA induces the activation of Erk1/2 is distinguishable from the mechanism of ER{alpha}-mediated signaling in human breast cancer cells.

  6. Rapid degradation of an active formylglycine generating enzyme variant leads to a late infantile severe form of multiple sulfatase deficiency.

    Science.gov (United States)

    Schlotawa, Lars; Radhakrishnan, Karthikeyan; Baumgartner, Matthias; Schmid, Regula; Schmidt, Bernhard; Dierks, Thomas; Gärtner, Jutta

    2013-09-01

    Multiple sulfatase deficiency (MSD) is a rare inborn error of metabolism affecting posttranslational activation of sulfatases by the formylglycine generating enzyme (FGE). Due to mutations in the encoding SUMF1 gene, FGE's catalytic capacity is impaired resulting in reduced cellular sulfatase activities. Both, FGE protein stability and residual activity determine disease severity and have previously been correlated with the clinical MSD phenotype. Here, we report a patient with a late infantile severe course of disease. The patient is compound heterozygous for two so far undescribed SUMF1 mutations, c.156delC (p.C52fsX57) and c.390A>T (p.E130D). In patient fibroblasts, mRNA of the frameshift allele is undetectable. In contrast, the allele encoding FGE-E130D is expressed. FGE-E130D correctly localizes to the endoplasmic reticulum and has a very high residual molecular activity in vitro (55% of wildtype FGE); however, it is rapidly degraded. Thus, despite substantial residual enzyme activity, protein instability determines disease severity, which highlights that potential MSD treatment approaches should target protein folding and stabilization mechanisms.

  7. Rapid photometry of EZ Canis Majoris - Searching for flare activity in Wolf-Rayet stars

    Science.gov (United States)

    Matthews, J. M.; Moffat, A. F. J.; Marchenko, S. V.

    1992-12-01

    EZ CMa was chosen for a trial run of high-speed photometry to search for flare activity in W-R stars. Data were collected during UT November 27-December 2, 1991 with the 1.0-telescope + ASCAP photometer and the 0.6-m telescope + manual photometer of the Cerro Tololo Inter-American Observatory. A period near 22.7 min was found. A brightness increase of about 1 percent, lasting for about 10 min in the otherwise smooth light curve, was observed. Fourier analysis of the data sets an upper limit of 0.0005 mag on any variations with periods less than about 10 min.

  8. Rapid adaptive remote focusing microscope for sensing of volumetric neural activity.

    Science.gov (United States)

    Žurauskas, Mantas; Barnstedt, Oliver; Frade-Rodriguez, Maria; Waddell, Scott; Booth, Martin J

    2017-10-01

    The ability to record neural activity in the brain of a living organism at cellular resolution is of great importance for defining the neural circuit mechanisms that direct behavior. Here we present an adaptive two-photon microscope optimized for extraction of neural signals over volumes in intact Drosophila brains, even in the presence of specimen motion. High speed volume imaging was made possible through reduction of spatial resolution while maintaining the light collection efficiency of a high resolution, high numerical aperture microscope. This enabled simultaneous recording of odor-evoked calcium transients in a defined volume of mushroom body Kenyon cell bodies in a live fruit fly.

  9. Acyl-CoA esters antagonize the effects of ligands on peroxisome proliferator-activated receptor alpha conformation, DNA binding, and interaction with Co-factors

    DEFF Research Database (Denmark)

    Elholm, M; Dam, I; Jorgensen, C

    2001-01-01

    palmitoyl-CoA analog, antagonizes the effects of agonists on PPARalpha conformation and function in vitro. In electrophoretic mobility shift assays, S-hexadecyl-CoA prevented agonist-induced binding of the PPARalpha-retinoid X receptor alpha heterodimer to the acyl-CoA oxidase peroxisome proliferator...... to the buffering effect of high affinity acyl-CoA-binding proteins, especially the acyl-CoA-binding protein. By using PPARalpha expressed in Sf21 cells for electrophoretic mobility shift assays, we demonstrate that S-hexadecyl-CoA was able to increase the mobility of the PPARalpha-containing heterodimer even...

  10. From starburst to quiescence: testing active galactic nucleus feedback in rapidly quenching post-starburst galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Yesuf, Hassen M.; Faber, S. M.; Trump, Jonathan R.; Koo, David C.; Fang, Jerome J.; Liu, F. S. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Wild, Vivienne [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS (United Kingdom); Hayward, Christopher C. [Heidelberger Institut für Theoretische Studien, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany)

    2014-09-10

    Post-starbursts are galaxies in transition from the blue cloud to the red sequence. Although they are rare today, integrated over time they may be an important pathway to the red sequence. This work uses Sloan Digital Sky Survey, the Galaxy Evolution Explorer, and Wide-field Infrared Survey Explorer observations to identify the evolutionary sequence from starbursts to fully quenched post-starbursts (QPSBs) in the narrow mass range log M(M {sub ☉}) = 10.3-10.7, and identifies 'transiting' post-starbursts (TPSBs) which are intermediate between these two populations. In this mass range, ∼0.3% of galaxies are starbursts, ∼0.1% are QPSBs, and ∼0.5% are the transiting types in between. The TPSBs have stellar properties that are predicted for fast-quenching starbursts and morphological characteristics that are already typical of early-type galaxies. The active galactic nucleus (AGN) fraction, as estimated from optical line ratios, of these post-starbursts is about three times higher (≳ 36% ± 8%) than that of normal star forming galaxies of the same mass, but there is a significant delay between the starburst phase and the peak of nuclear optical AGN activity (median age difference of ≳ 200 ± 100 Myr), in agreement with previous studies. The time delay is inferred by comparing the broadband near-NUV-to-optical photometry with stellar population synthesis models. We also find that starbursts and post-starbursts are significantly more dust obscured than normal star forming galaxies in the same mass range. About 20% of the starbursts and 15% of the TPSBs can be classified as 'dust-obscured galaxies' (DOGs), with a near-UV-to-mid-IR flux ratio of ≳ 900, while only 0.8% of normal galaxies are DOGs. The time delay between the starburst phase and AGN activity suggests that AGNs do not play a primary role in the original quenching of starbursts but may be responsible for quenching later low-level star formation by removing gas and dust during

  11. Emergency Department Visit Data for Rapid Detection and Monitoring of Norovirus Activity, United States

    Science.gov (United States)

    Burrer, Sherry; Park, Soyoun; Trivedi, Tarak; Parashar, Umesh D.; Lopman, Benjamin A.

    2013-01-01

    Noroviruses are the leading cause of gastroenteritis in the United States, but timely measures of disease are lacking. BioSense, a national-level electronic surveillance system, assigns data on chief complaints (patient symptoms) collected during emergency department (ED) visits to 78 subsyndromes in near real-time. In a series of linear regression models, BioSense visits mapped by chief complaints of diarrhea and nausea/vomiting subsyndromes as a monthly proportion of all visits correlated strongly with reported norovirus outbreaks from 6 states during 2007–2010. Higher correlations were seen for diarrhea (R = 0.828–0.926) than for nausea/vomiting (R = 0.729–0.866) across multiple age groups. Diarrhea ED visit proportions exhibited winter seasonality attributable to norovirus; rotavirus contributed substantially for children norovirus season within 4 weeks of observed dates and could be reliable, timely indicators of norovirus activity. PMID:23876432

  12. Functionally Active Fc Mutant Antibodies Recognizing Cancer Antigens Generated Rapidly at High Yields

    Directory of Open Access Journals (Sweden)

    Kristina M. Ilieva

    2017-09-01

    Full Text Available Monoclonal antibodies find broad application as therapy for various types of cancer by employing multiple mechanisms of action against tumors. Manipulating the Fc-mediated functions of antibodies that engage immune effector cells, such as NK cells, represents a strategy to influence effector cell activation and to enhance antibody potency and potentially efficacy. We developed a novel approach to generate and ascertain the functional attributes of Fc mutant monoclonal antibodies. This entailed coupling single expression vector (pVitro1 antibody cloning, using polymerase incomplete primer extension (PIPE polymerase chain reaction, together with simultaneous Fc region point mutagenesis and high yield transient expression in human mammalian cells. Employing this, we engineered wild type, low (N297Q, NQ, and high (S239D/I332E, DE FcR-binding Fc mutant monoclonal antibody panels recognizing two cancer antigens, HER2/neu and chondroitin sulfate proteoglycan 4. Antibodies were generated with universal mutagenic primers applicable to any IgG1 pVitro1 constructs, with high mutagenesis and transfection efficiency, in small culture volumes, at high yields and within 12 days from design to purified material. Antibody variants conserved their Fab-mediated recognition of target antigens and their direct anti-proliferative effects against cancer cells. Fc mutations had a significant impact on antibody interactions with Fc receptors (FcRs on human NK cells, and consequently on the potency of NK cell activation, quantified by immune complex-mediated calcium mobilization and by antibody-dependent cellular cytotoxicity (ADCC of tumor cells. This strategy for manipulation and testing of Fc region engagement with cognate FcRs can facilitate the design of antibodies with defined effector functions and potentially enhanced efficacy against tumor cells.

  13. Discovery of small molecules binding to the normal conformation of prion by combining virtual screening and multiple biological activity evaluation methods

    Science.gov (United States)

    Li, Lanlan; Wei, Wei; Jia, Wen-Juan; Zhu, Yongchang; Zhang, Yan; Chen, Jiang-Huai; Tian, Jiaqi; Liu, Huanxiang; He, Yong-Xing; Yao, Xiaojun

    2017-12-01

    Conformational conversion of the normal cellular prion protein, PrPC, into the misfolded isoform, PrPSc, is considered to be a central event in the development of fatal neurodegenerative diseases. Stabilization of prion protein at the normal cellular form (PrPC) with small molecules is a rational and efficient strategy for treatment of prion related diseases. However, few compounds have been identified as potent prion inhibitors by binding to the normal conformation of prion. In this work, to rational screening of inhibitors capable of stabilizing cellular form of prion protein, multiple approaches combining docking-based virtual screening, steady-state fluorescence quenching, surface plasmon resonance and thioflavin T fluorescence assay were used to discover new compounds interrupting PrPC to PrPSc conversion. Compound 3253-0207 that can bind to PrPC with micromolar affinity and inhibit prion fibrillation was identified from small molecule databases. Molecular dynamics simulation indicated that compound 3253-0207 can bind to the hotspot residues in the binding pocket composed by β1, β2 and α2, which are significant structure moieties in conversion from PrPC to PrPSc.

  14. Rapid and minimum invasive functional brain mapping by real-time visualization of high gamma activity during awake craniotomy.

    Science.gov (United States)

    Ogawa, Hiroshi; Kamada, Kyousuke; Kapeller, Christoph; Hiroshima, Satoru; Prueckl, Robert; Guger, Christoph

    2014-11-01

    Electrocortical stimulation (ECS) is the gold standard for functional brain mapping during an awake craniotomy. The critical issue is to set aside enough time to identify eloquent cortices by ECS. High gamma activity (HGA) ranging between 80 and 120 Hz on electrocorticogram is assumed to reflect localized cortical processing. In this report, we used real-time HGA mapping and functional neuronavigation integrated with functional magnetic resonance imaging (fMRI) for rapid and reliable identification of motor and language functions. Four patients with intra-axial tumors in their dominant hemisphere underwent preoperative fMRI and lesion resection with an awake craniotomy. All patients showed significant fMRI activation evoked by motor and language tasks. During the craniotomy, we recorded electrocorticogram activity by placing subdural grids directly on the exposed brain surface. Each patient performed motor and language tasks and demonstrated real-time HGA dynamics in hand motor areas and parts of the inferior frontal gyrus. Sensitivity and specificity of HGA mapping were 100% compared with ECS mapping in the frontal lobe, which suggested HGA mapping precisely indicated eloquent cortices. We found different HGA dynamics of language tasks in frontal and temporal regions. Specificities of the motor and language-fMRI did not reach 85%. The results of HGA mapping was mostly consistent with those of ECS mapping, although fMRI tended to overestimate functional areas. This novel technique enables rapid and accurate identification of motor and frontal language areas. Furthermore, real-time HGA mapping sheds light on underlying physiological mechanisms related to human brain functions. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Conformal Janus on Euclidean sphere

    Energy Technology Data Exchange (ETDEWEB)

    Bak, Dongsu [Physics Department, University of Seoul,Seoul 02504 (Korea, Republic of); B.W. Lee Center for Fields, Gravity & Strings, Institute for Basic Sciences,Daejeon 34047 (Korea, Republic of); Gustavsson, Andreas [School of Physics, Korea Institute for Advanced Study,Seoul 02455 (Korea, Republic of); Rey, Soo-Jong [School of Physics & Astronomy and Center for Theoretical Physics,Seoul National University,Seoul 08826 (Korea, Republic of); Center for Theoretical Physics, College of Physical Sciences, Sichuan University,Chengdu 610064 P.R. (China); B.W. Lee Center for Fields, Gravity & Strings, Institute for Basic Sciences,Daejeon 34047 (Korea, Republic of)

    2016-12-07

    We interpret Janus as an interface in a conformal field theory and study its properties. The Janus is created by an exactly marginal operator and we study its effect on the interface conformal field theory on the Janus. We do this by utilizing the AdS/CFT correspondence. We compute the interface free energy both from leading correction to the Euclidean action in the dual gravity description and from conformal perturbation theory in the conformal field theory. We find that the two results agree each other and that the interface free energy scales precisely as expected from the conformal invariance of the Janus interface.

  16. Pharmacological activation of rapid delayed rectifier potassium current suppresses bradycardia-induced triggered activity in the isolated guinea pig heart

    DEFF Research Database (Denmark)

    Hansen, Rie Schultz; Olesen, Søren-Peter; Grunnet, Morten

    2007-01-01

    arrhythmias. We present here data that support that NS3623 affects native I(Kr) and report the effects that activating this potassium current have in the intact guinea pig heart. In Langendorff-perfused hearts, the compound showed a concentration-dependent shortening of action potential duration, which...... was also detected as concentration-dependent shorter QT intervals. There was no sign of action potential triangulation or reverse use dependence. NS3623 decreased QT variability and distinctly decreased the occurrence of extrasystoles in the acutely bradypaced hearts. Taken together, the present data...

  17. A Design Methodology for Rapid Implementation of Active Control Systems Across Lean Direct Injection Combustor Platforms

    Science.gov (United States)

    Baumann, William T.; Saunders, William R.; Vandsburger, Uri; Saus, Joseph (Technical Monitor)

    2003-01-01

    The VACCG team is comprised of engineers at Virginia Tech who specialize in the subject areas of combustion physics, chemical kinetics, dynamics and controls, and signal processing. Currently, the team's work on this NRA research grant is designed to determine key factors that influence combustion control performance through a blend of theoretical and experimental investigations targeting design and demonstration of active control for three different combustors. To validiate the accuracy of conclusions about control effectiveness, a sequence of experimental verifications on increasingly complex lean, direct injection combustors is underway. During the work period January 1, 2002 through October 15, 2002, work has focused on two different laboratory-scale combustors that allow access for a wide variety of measurements. As the grant work proceeds, one key goal will be to obtain certain knowledge about a particular combustor process using a minimum of sophisticated measurements, due to the practical limitations of measurements on full-scale combustors. In the second year, results obtained in the first year will be validated on test combustors to be identified in the first quarter of that year. In the third year, it is proposed to validate the results at more realistic pressure and power levels by utilizing the facilities at the Glenn Research Center.

  18. WIZARD: AI in conformational analysis

    Science.gov (United States)

    Dolata, Daniel P.; Leach, Andrew R.; Prout, Keith

    1987-04-01

    A program which utilizes the techniques of Artificial Intelligence and Expert Systems to solve problems in the area of Conformational Analysis is described. The program searches conformational space in a systematic fashion, based on the technique known as heuristic state-space search. The program proceeds by recognizing conformational units, assigning one or more conformational templates to each unit, and joining them to form conformational suggestions. These suggestions are criticized to discover logical inconsistencies, and any resulting stresses are resolved. The resulting conformational suggestions are sometimes accurate enough for immediate use, or may be further refined by a numerical program. The latter combination is shown to be quite efficient compared to purely numerical conformational search techniques.

  19. Active machine learning for rapid landslide inventory mapping with VHR satellite images (Invited)

    Science.gov (United States)

    Stumpf, A.; Lachiche, N.; Malet, J.; Kerle, N.; Puissant, A.

    2013-12-01

    VHR satellite images have become a primary source for landslide inventory mapping after major triggering events such as earthquakes and heavy rainfalls. Visual image interpretation is still the prevailing standard method for operational purposes but is time-consuming and not well suited to fully exploit the increasingly better supply of remote sensing data. Recent studies have addressed the development of more automated image analysis workflows for landslide inventory mapping. In particular object-oriented approaches that account for spatial and textural image information have been demonstrated to be more adequate than pixel-based classification but manually elaborated rule-based classifiers are difficult to adapt under changing scene characteristics. Machine learning algorithm allow learning classification rules for complex image patterns from labelled examples and can be adapted straightforwardly with available training data. In order to reduce the amount of costly training data active learning (AL) has evolved as a key concept to guide the sampling for many applications. The underlying idea of AL is to initialize a machine learning model with a small training set, and to subsequently exploit the model state and data structure to iteratively select the most valuable samples that should be labelled by the user. With relatively few queries and labelled samples, an AL strategy yields higher accuracies than an equivalent classifier trained with many randomly selected samples. This study addressed the development of an AL method for landslide mapping from VHR remote sensing images with special consideration of the spatial distribution of the samples. Our approach [1] is based on the Random Forest algorithm and considers the classifier uncertainty as well as the variance of potential sampling regions to guide the user towards the most valuable sampling areas. The algorithm explicitly searches for compact regions and thereby avoids a spatially disperse sampling pattern

  20. Interaction between the long-latency stretch reflex and voluntary electromyographic activity prior to a rapid voluntary motor reaction.

    Science.gov (United States)

    Day, B L; Rothwell, J C; Marsden, C D

    1983-06-27

    The size of the long-latency component of the stretch reflex has been examined in the time interval between a signal to move and the required rapid voluntary contraction of triceps and flexor pollicis longus in 8 normal subjects. Bilateral movements of the elbow and thumb were made following an auditory signal. In 50% of the trials a torque pulse was applied unilaterally in order to elicit a stretch reflex response in one arm. The voluntary response in the contralateral arm was uncorrupted by a stretch reflex response, so was used as an indicator of voluntary reaction time. Control experiments, using an electrical stimulus to the fingers rather than muscle stretch, verified that both arms reacted almost simultaneously to the auditory cue, even when the reaction time was shortened by the presence of a unilateral electrical stimulus. Similarly, an interposed muscle stretch stimulus considerably reduced the reaction time to the audio signal. Because of this, the start of the voluntary EMG response frequently 'over-lapped' the end of the long-latency stretch reflex. Failure to take this shortening of voluntary reaction time into consideration can lead to the erroneous conclusion that reflex gain is increased prior to a rapid movement. If the 'overlap' of EMG responses is accounted for, very little change in the size of the long-latency stretch reflex is evident prior to activation of the muscles responsible for the movement of either the elbow or the thumb.

  1. A Force-Activated Trip Switch Triggers Rapid Dissociation of a Colicin from Its Immunity Protein

    Science.gov (United States)

    Farrance, Oliver E.; Hann, Eleanore; Kaminska, Renata; Housden, Nicholas G.; Derrington, Sasha R.; Kleanthous, Colin; Radford, Sheena E.; Brockwell, David J.

    2013-01-01

    Colicins are protein antibiotics synthesised by Escherichia coli strains to target and kill related bacteria. To prevent host suicide, colicins are inactivated by binding to immunity proteins. Despite their high avidity (Kd≈fM, lifetime ≈4 days), immunity protein release is a pre-requisite of colicin intoxication, which occurs on a timescale of minutes. Here, by measuring the dynamic force spectrum of the dissociation of the DNase domain of colicin E9 (E9) and immunity protein 9 (Im9) complex using an atomic force microscope we show that application of low forces (force-triggered increase in off-rate a trip bond. Using mutational analysis, we elucidate the mechanism of this switch in affinity. We show that the N-terminal region of E9, which has sparse contacts with the hydrophobic core, is linked to an allosteric activator region in E9 (residues 21–30) whose remodelling triggers immunity protein release. Diversion of the force transduction pathway by the introduction of appropriately positioned disulfide bridges yields a force resistant complex with a lifetime identical to that measured by ensemble techniques. A trip switch within E9 is ideal for its function as it allows bipartite complex affinity, whereby the stable colicin:immunity protein complex required for host protection can be readily converted to a kinetically unstable complex whose dissociation is necessary for cellular invasion and competitor death. More generally, the observation of two force phenotypes for the E9:Im9 complex demonstrates that force can re-sculpt the underlying energy landscape, providing new opportunities to modulate biological reactions in vivo; this rationalises the commonly observed discrepancy between off-rates measured by dynamic force spectroscopy and ensemble methods. PMID:23431269

  2. A force-activated trip switch triggers rapid dissociation of a colicin from its immunity protein.

    Directory of Open Access Journals (Sweden)

    Oliver E Farrance

    Full Text Available Colicins are protein antibiotics synthesised by Escherichia coli strains to target and kill related bacteria. To prevent host suicide, colicins are inactivated by binding to immunity proteins. Despite their high avidity (K(d ≈ fM, lifetime ≈ 4 days, immunity protein release is a pre-requisite of colicin intoxication, which occurs on a timescale of minutes. Here, by measuring the dynamic force spectrum of the dissociation of the DNase domain of colicin E9 (E9 and immunity protein 9 (Im9 complex using an atomic force microscope we show that application of low forces (<20 pN increases the rate of complex dissociation 10(6-fold, to a timescale (lifetime ≈ 10 ms compatible with intoxication. We term this catastrophic force-triggered increase in off-rate a trip bond. Using mutational analysis, we elucidate the mechanism of this switch in affinity. We show that the N-terminal region of E9, which has sparse contacts with the hydrophobic core, is linked to an allosteric activator region in E9 (residues 21-30 whose remodelling triggers immunity protein release. Diversion of the force transduction pathway by the introduction of appropriately positioned disulfide bridges yields a force resistant complex with a lifetime identical to that measured by ensemble techniques. A trip switch within E9 is ideal for its function as it allows bipartite complex affinity, whereby the stable colicin:immunity protein complex required for host protection can be readily converted to a kinetically unstable complex whose dissociation is necessary for cellular invasion and competitor death. More generally, the observation of two force phenotypes for the E9:Im9 complex demonstrates that force can re-sculpt the underlying energy landscape, providing new opportunities to modulate biological reactions in vivo; this rationalises the commonly observed discrepancy between off-rates measured by dynamic force spectroscopy and ensemble methods.

  3. Macrophage activation-like syndrome: an immunological entity associated with rapid progression to death in sepsis.

    Science.gov (United States)

    Kyriazopoulou, Evdoxia; Leventogiannis, Konstantinos; Norrby-Teglund, Anna; Dimopoulos, Georgios; Pantazi, Aikaterini; Orfanos, Stylianos E; Rovina, Nikoletta; Tsangaris, Iraklis; Gkavogianni, Theologia; Botsa, Elektra; Chassiou, Eleftheria; Kotanidou, Anastasia; Kontouli, Christina; Chaloulis, Panagiotis; Velissaris, Dimitrios; Savva, Athina; Cullberg, Jonas-Sundén; Akinosoglou, Karolina; Gogos, Charalambos; Armaganidis, Apostolos; Giamarellos-Bourboulis, Evangelos J

    2017-09-18

    A subanalysis of a randomized clinical trial indicated sepsis survival benefit from interleukin (IL)-1 blockade in patients with features of the macrophage activation-like syndrome (MALS). This study aimed to investigate the frequency of MALS and to develop a biomarker of diagnosis and prognosis. Patients with infections and systemic inflammatory response syndrome were assigned to one test cohort (n = 3417) and a validation cohort (n = 1704). MALS was diagnosed for patients scoring positive either for the hemophagocytic syndrome score and/or having both hepatobiliary dysfunction and disseminated intravascular coagulation. Logistic regression analysis was used to estimate the predictive value of MALS for 10-day mortality in both cohorts. Ferritin, sCD163, IL-6, IL-10, IL-18, interferon gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α) were measured in the blood the first 24 h; ferritin measurements were repeated in 747 patients on day 3. The frequency of MALS was 3.7% and 4.3% in the test and the validation cohort, respectively. In both cohorts, MALS was an independent risk factor for 10-day mortality. A ferritin level above 4420 ng/ml was accompanied by 66.7% and 66% mortality after 28 days, respectively. Ferritin levels above 4420 ng/ml were associated with an increase of IL-6, IL-18, INF-γ, and sCD163 and a decreased IL-10/TNF-α ratio, indicating predominance of pro-inflammatory phenomena. Any less than 15% decrease of ferritin on day 3 was associated with more than 90% sensitivity for unfavorable outcome after 10 days. This high mortality risk was also validated in an independent Swedish cohort (n = 109). MALS is an independent life-threatening entity in sepsis. Ferritin measurements can provide early diagnosis of MALS and may allow for specific treatment.

  4. An Efficient Null Model for Conformational Fluctuations in Proteins

    DEFF Research Database (Denmark)

    Harder, Tim Philipp; Borg, Mikael; Bottaro, Sandro

    2012-01-01

    Protein dynamics play a crucial role in function, catalytic activity, and pathogenesis. Consequently, there is great interest in computational methods that probe the conformational fluctuations of a protein. However, molecular dynamics simulations are computationally costly and therefore are often...... limited to comparatively short timescales. TYPHON is a probabilistic method to explore the conformational space of proteins under the guidance of a sophisticated probabilistic model of local structure and a given set of restraints that represent nonlocal interactions, such as hydrogen bonds or disulfide...... on conformational fluctuations that is in correspondence with experimental measurements. TYPHON provides a flexible, yet computationally efficient, method to explore possible conformational fluctuations in proteins....

  5. Conformance and Deviance

    DEFF Research Database (Denmark)

    Gjerdrum Pedersen, Esben Rahbek; Neergaard, Peter; Thusgaard Pedersen, Janni

    2013-01-01

    This paper analyses how large Danish companies are responding to new governmental regulation which requires them to report on corporate social responsibility (CSR). The paper is based on an analysis of 142 company annual reports required by the new Danish regulation regarding CSR reporting, plus ...... in CSR reporting practices. Finally, it is argued that non-conformance with the new regulatory requirements is not solely about conscious resistance but may also be caused by, for example, lack of awareness, resource limitations, misinterpretations, and practical difficulties....

  6. Rapid isolation of a facultative anaerobic electrochemically active bacterium capable of oxidizing acetate for electrogenesis and azo dyes reduction.

    Science.gov (United States)

    Shen, Nan; Yuan, Shi-Jie; Wu, Chao; Cheng, Yuan-Yuan; Song, Xiang-Ning; Li, Wen-Wei; Tong, Zhong-Hua; Yu, Han-Qing

    2014-05-01

    In this study, 27 strains of electrochemically active bacteria (EAB) were rapidly isolated and their capabilities of extracellular electron transfer were identified using a photometric method based on WO3 nanoclusters. These strains caused color change of WO3 from white to blue in a 24-well agar plate within 40 h. Most of the isolated EAB strains belonged to the genera of Aeromonas and Shewanella. One isolate, Pantoea agglomerans S5-44, was identified as an EAB that can utilize acetate as the carbon source to produce electricity and reduce azo dyes under anaerobic conditions. The results confirmed the capability of P. agglomerans S5-44 for extracellular electron transfer. The isolation of this acetate-utilizing, facultative EBA reveals the metabolic diversity of environmental bacteria. Such strains have great potential for environmental applications, especially at interfaces of aerobic and anaerobic environments, where acetate is the main available carbon source.

  7. Ionic interactions and the global conformations of the hammerhead ribozyme

    DEFF Research Database (Denmark)

    Bassi, G S; Møllegaard, N E; Murchie, A I

    1995-01-01

    by the remaining helix I. In the probable active conformation, a small angle is subtended between helices I and II. Using uranyl photocleavage, an ion binding site has been detected in the long single-stranded region. The folded conformation could generate a preactivation of the scissile bond to permit in...

  8. Increasing Ubiquitin Ion Resistance to Unfolding in the Gas Phase Using Chloride Adduction: Preserving More "Native-Like" Conformations Despite Collisional Activation.

    Science.gov (United States)

    Wagner, Nicole D; Kim, Doyong; Russell, David H

    2016-06-07

    Electrospray ionization (ESI) of ubiquitin from acidified (0.1%) aqueous solution produces abundant ubiquitin-chloride adduct ions, [M + nH + xCl]((n - x)+), that upon mild heating react via elimination of neutral HCl. Ion mobility collision cross section (CCS) measurements show that ubiquitin ions retaining chloride adducts exhibit CCS values similar to those of the "native-state" of the protein. Coupled with results from recent molecular dynamics (MD) simulations for the evolution of a salt-containing electrospray droplet, this study provides a more complete picture for how the presence of salts affects the evolution of protein conformers in the final stages of dehydration of the ESI process and within the instrument.

  9. Dynamic changes in single unit activity and γ oscillations in a thalamocortical circuit during rapid instrumental learning.

    Directory of Open Access Journals (Sweden)

    Chunxiu Yu

    Full Text Available The medial prefrontal cortex (mPFC and mediodorsal thalamus (MD together form a thalamocortical circuit that has been implicated in the learning and production of goal-directed actions. In this study we measured neural activity in both regions simultaneously, as rats learned to press a lever to earn food rewards. In both MD and mPFC, instrumental learning was accompanied by dramatic changes in the firing patterns of the neurons, in particular the rapid emergence of single-unit neural activity reflecting the completion of the action and reward delivery. In addition, we observed distinct patterns of changes in the oscillatory LFP response in MD and mPFC. With learning, there was a significant increase in theta band oscillations (6-10 Hz in the MD, but not in the mPFC. By contrast, gamma band oscillations (40-55 Hz increased in the mPFC, but not in the MD. Coherence between these two regions also changed with learning: gamma coherence in relation to reward delivery increased, whereas theta coherence did not. Together these results suggest that, as rats learned the instrumental contingency between action and outcome, the emergence of task related neural activity is accompanied by enhanced functional interaction between MD and mPFC in response to the reward feedback.

  10. Estrogen activates rapid signaling in the brain: role of estrogen receptor alpha and estrogen receptor beta in neurons and glia.

    Science.gov (United States)

    Mhyre, A J; Dorsa, D M

    2006-01-01

    The aging process is known to coincide with a decline in circulating sex hormone levels in both men and women. Due to an increase in the average lifespan, a growing number of post-menopausal women are now receiving hormone therapy for extended periods of time. Recent findings of the Women's Health Initiative, however, have called into question the benefits of long-term hormone therapy for treating symptoms of menopause. The results of this study are still being evaluated, but it is clear that a better understanding of the molecular effects of estradiol is needed in order to develop new estrogenic compounds that activate specific mechanisms but lack adverse side effects. Traditionally, the effects of estradiol treatment have been ascribed to changes in gene expression, namely transcription at estrogen response elements. This review focuses on emerging information that estradiol can also activate a repertoire of membrane-initiated signaling pathways and that these rapid signaling events lead to functional changes at the cellular level. The various types of cells in the brain can respond differently to estradiol treatment based on the signaling properties of the cell, as well as which receptor, estrogen receptor alpha and/or estrogen receptor beta, is expressed. Taken together, these findings suggest that the estradiol-induced activation of membrane-initiated signaling pathways occurs in a cell-type specific manner and can differentially influence how the cells respond to various insults.

  11. A CENSUS OF BROAD-LINE ACTIVE GALACTIC NUCLEI IN NEARBY GALAXIES: COEVAL STAR FORMATION AND RAPID BLACK HOLE GROWTH

    Energy Technology Data Exchange (ETDEWEB)

    Trump, Jonathan R.; Fang, Jerome J.; Faber, S. M.; Koo, David C.; Kocevski, Dale D. [University of California Observatories/Lick Observatory and Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Hsu, Alexander D. [The Harker School, 500 Saratoga Avenue, San Jose, CA 95129 (United States)

    2013-02-15

    We present the first quantified, statistical map of broad-line active galactic nucleus (AGN) frequency with host galaxy color and stellar mass in nearby (0.01 < z < 0.11) galaxies. Aperture photometry and z-band concentration measurements from the Sloan Digital Sky Survey are used to disentangle AGN and galaxy emission, resulting in estimates of uncontaminated galaxy rest-frame color, luminosity, and stellar mass. Broad-line AGNs are distributed throughout the blue cloud and green valley at a given stellar mass, and are much rarer in quiescent (red sequence) galaxies. This is in contrast to the published host galaxy properties of weaker narrow-line AGNs, indicating that broad-line AGNs occur during a different phase in galaxy evolution. More luminous broad-line AGNs have bluer host galaxies, even at fixed mass, suggesting that the same processes that fuel nuclear activity also efficiently form stars. The data favor processes that simultaneously fuel both star formation activity and rapid supermassive black hole accretion. If AGNs cause feedback on their host galaxies in the nearby universe, the evidence of galaxy-wide quenching must be delayed until after the broad-line AGN phase.

  12. Discovery and characteristics of the rapidly rotating active asteroid (62412) 2000 SY178 in the main belt

    Energy Technology Data Exchange (ETDEWEB)

    Sheppard, Scott S. [Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road. NW, Washington, DC 20015 (United States); Trujillo, Chadwick, E-mail: ssheppard@carnegiescience.edu [Gemini Observatory, 670 North A‘ohoku Place, Hilo, HI 96720 (United States)

    2015-02-01

    We report a new active asteroid in the main belt of asteroids between Mars and Jupiter. Object (62412) 2000 SY178 exhibited a tail in images collected during our survey for objects beyond the Kuiper Belt using the Dark Energy Camera on the CTIO 4 m telescope. We obtained broadband colors of 62412 at the Magellan Telescope, which, along with 62412's low albedo, suggests it is a C-type asteroid. 62412's orbital dynamics and color strongly correlate with the Hygiea family in the outer main belt, making it the first active asteroid known in this heavily populated family. We also find 62412 to have a very short rotation period of 3.33 ± 0.01 hours from a double-peaked light curve with a maximum peak-to-peak amplitude of 0.45 ± 0.01 mag. We identify 62412 as the fastest known rotator of the Hygiea family and the nearby Themis family of similar composition, which contains several known main belt comets. The activity on 62412 was seen over one year after perihelion passage in its 5.6 year orbit. 62412 has the highest perihelion and one of the most circular orbits known for any active asteroid. The observed activity is probably linked to 62412's rapid rotation, which is near the critical period for break-up. The fast spin rate may also change the shape and shift material around 62412's surface, possibly exposing buried ice. Assuming 62412 is a strengthless rubble pile, we find the density of 62412 to be around 1500 kg m{sup −3}.

  13. Supergravitational conformal Galileons

    Science.gov (United States)

    Deen, Rehan; Ovrut, Burt

    2017-08-01

    The worldvolume actions of 3+1 dimensional bosonic branes embedded in a five-dimensional bulk space can lead to important effective field theories, such as the DBI conformal Galileons, and may, when the Null Energy Condition is violated, play an essential role in cosmological theories of the early universe. These include Galileon Genesis and "bouncing" cosmology, where a pre-Big Bang contracting phase bounces smoothly to the presently observed expanding universe. Perhaps the most natural arena for such branes to arise is within the context of superstring and M -theory vacua. Here, not only are branes required for the consistency of the theory, but, in many cases, the exact spectrum of particle physics occurs at low energy. However, such theories have the additional constraint that they must be N = 1 supersymmetric. This motivates us to compute the worldvolume actions of N = 1 supersymmetric three-branes, first in flat superspace and then to generalize them to N = 1 supergravitation. In this paper, for simplicity, we begin the process, not within the context of a superstring vacuum but, rather, for the conformal Galileons arising on a co-dimension one brane embedded in a maximally symmetric AdS 5 bulk space. We proceed to N = 1 supersymmetrize the associated worldvolume theory and then generalize the results to N = 1 supergravity, opening the door to possible new cosmological scenarios

  14. Estrogen Receptor β Activation Rapidly Modulates Male Sexual Motivation through the Transactivation of Metabotropic Glutamate Receptor 1a

    Science.gov (United States)

    Seredynski, Aurore L.; Balthazart, Jacques; Ball, Gregory F.

    2015-01-01

    In addition to the transcriptional activity of their liganded nuclear receptors, estrogens, such as estradiol (E2), modulate cell functions, and consequently physiology and behavior, within minutes through membrane-initiated events. The membrane-associated receptors (mERs) underlying the acute effects of estrogens on behavior have mostly been documented in females where active estrogens are thought to be of ovarian origin. We determined here, by acute intracerebroventricular injections of specific agonists and antagonists, the type(s) of mERs that modulate rapid effects of brain-derived estrogens on sexual motivation in male Japanese quail. Brain aromatase blockade acutely inhibited sexual motivation. Diarylpropionitrile (DPN), an estrogen receptor β (ERβ)-specific agonist, and to a lesser extent 17α-estradiol, possibly acting through ER-X, prevented this effect. In contrast, drugs targeting ERα (PPT and MPP), GPR30 (G1 and G15), and the Gq-mER (STX) did not affect sexual motivation. The mGluR1a antagonist LY367385 significantly inhibited sexual motivation but mGluR2/3 and mGluR5 antagonists were ineffective. LY367385 also blocked the behavioral restoration induced by E2 or DPN, providing functional evidence that ERβ interacts with metabotropic glutamate receptor 1a (mGluR1a) signaling to acutely regulate male sexual motivation. Together these results show that ERβ plays a key role in sexual behavior regulation and the recently uncovered cooperation between mERs and mGluRs is functional in males where it mediates the acute effects of estrogens produced centrally in response to social stimuli. The presence of an ER–mGluR interaction in birds suggests that this mechanism emerged relatively early in vertebrate history and is well conserved. SIGNIFICANCE STATEMENT The membrane-associated receptors underlying the acute effects of estrogens on behavior have mostly been documented in females, where active estrogens are thought to be of ovarian origin. Using acute

  15. Baseline Levels of Rapid Eye Movement Sleep May Protect Against Excessive Activity in Fear-Related Neural Circuitry.

    Science.gov (United States)

    Lerner, Itamar; Lupkin, Shira M; Sinha, Neha; Tsai, Alan; Gluck, Mark A

    2017-11-15

    Sleep, and particularly rapid eye movement sleep (REM), has been implicated in the modulation of neural activity following fear conditioning and extinction in both human and animal studies. It has long been presumed that such effects play a role in the formation and persistence of posttraumatic stress disorder, of which sleep impairments are a core feature. However, to date, few studies have thoroughly examined the potential effects of sleep prior to conditioning on subsequent acquisition of fear learning in humans. Furthermore, these studies have been restricted to analyzing the effects of a single night of sleep-thus assuming a state-like relationship between the two. In the current study, we used long-term mobile sleep monitoring and functional neuroimaging (fMRI) to explore whether trait-like variations in sleep patterns, measured in advance in both male and female participants, predict subsequent patterns of neural activity during fear learning. Our results indicate that higher baseline levels of REM sleep predict reduced fear-related activity in, and connectivity between, the hippocampus, amygdala and ventromedial PFC during conditioning. Additionally, skin conductance responses (SCRs) were weakly correlated to the activity in the amygdala. Conversely, there was no direct correlation between REM sleep and SCRs, indicating that REM may only modulate fear acquisition indirectly. In a follow-up experiment, we show that these results are replicable, though to a lesser extent, when measuring sleep over a single night just before conditioning. As such, baseline sleep parameters may be able to serve as biomarkers for resilience, or lack thereof, to trauma. SIGNIFICANCE STATEMENT Numerous studies over the past two decades have established a clear role of sleep in fear-learning processes. However, previous work has focused on the effects of sleep following fear acquisition, thus neglecting the potential effects of baseline sleep levels on the acquisition itself. The

  16. Rapid eye movement (REM sleep deprivation reduces rat frontal cortex acetylcholinesterase (EC 3.1.1.7 activity

    Directory of Open Access Journals (Sweden)

    Camarini R.

    1997-01-01

    Full Text Available Rapid eye movement (REM sleep deprivation induces several behavioral changes. Among these, a decrease in yawning behavior produced by low doses of cholinergic agonists is observed which indicates a change in brain cholinergic neurotransmission after REM sleep deprivation. Acetylcholinesterase (Achase controls acetylcholine (Ach availability in the synaptic cleft. Therefore, altered Achase activity may lead to a change in Ach availability at the receptor level which, in turn, may result in modification of cholinergic neurotransmission. To determine if REM sleep deprivation would change the activity of Achase, male Wistar rats, 3 months old, weighing 250-300 g, were deprived of REM sleep for 96 h by the flower-pot technique (N = 12. Two additional groups, a home-cage control (N = 6 and a large platform control (N = 6, were also used. Achase was measured in the frontal cortex using two different methods to obtain the enzyme activity. One method consisted of the obtention of total (900 g supernatant, membrane-bound (100,000 g pellet and soluble (100,000 g supernatant Achase, and the other method consisted of the obtention of a fraction (40,000 g pellet enriched in synaptic membrane-bound enzyme. In both preparations, REM sleep deprivation induced a significant decrease in rat frontal cortex Achase activity when compared to both home-cage and large platform controls. REM sleep deprivation induced a significant decrease of 16% in the membrane-bound Achase activity (nmol thiocholine formed min-1 mg protein-1 in the 100,000 g pellet enzyme preparation (home-cage group 152.1 ± 5.7, large platform group 152.7 ± 24.9 and REM sleep-deprived group 127.9 ± 13.8. There was no difference in the soluble enzyme activity. REM sleep deprivation also induced a significant decrease of 20% in the enriched synaptic membrane-bound Achase activity (home-cage group 126.4 ± 21.5, large platform group 127.8 ± 20.4, REM sleep-deprived group 102.8 ± 14.2. Our results

  17. Development of a rapid soil water content detection technique using active infrared thermal methods for in-field applications.

    Science.gov (United States)

    Antonucci, Francesca; Pallottino, Federico; Costa, Corrado; Rimatori, Valentina; Giorgi, Stefano; Papetti, Patrizia; Menesatti, Paolo

    2011-01-01

    The aim of this study was to investigate the suitability of active infrared thermography and thermometry in combination with multivariate statistical partial least squares analysis as rapid soil water content detection techniques both in the laboratory and the field. Such techniques allow fast soil water content measurements helpful in both agricultural and environmental fields. These techniques, based on the theory of heat dissipation, were tested by directly measuring temperature dynamic variation of samples after heating. For the assessment of temperature dynamic variations data were collected during three intervals (3, 6 and 10 s). To account for the presence of specific heats differences between water and soil, the analyses were regulated using slopes to linearly describe their trends. For all analyses, the best model was achieved for a 10 s slope. Three different approaches were considered, two in the laboratory and one in the field. The first laboratory-based one was centred on active infrared thermography, considered measurement of temperature variation as independent variable and reported r = 0.74. The second laboratory-based one was focused on active infrared thermometry, added irradiation as independent variable and reported r = 0.76. The in-field experiment was performed by active infrared thermometry, heating bare soil by solar irradiance after exposure due to primary tillage. Some meteorological parameters were inserted as independent variables in the prediction model, which presented r = 0.61. In order to obtain more general and wide estimations in-field a Partial Least Squares Discriminant Analysis on three classes of percentage of soil water content was performed obtaining a high correct classification in the test (88.89%). The prediction error values were lower in the field with respect to laboratory analyses. Both techniques could be used in conjunction with a Geographic Information System for obtaining detailed information on soil heterogeneity.

  18. Development of a Rapid Soil Water Content Detection Technique Using Active Infrared Thermal Methods for In-Field Applications

    Directory of Open Access Journals (Sweden)

    Federico Pallottino

    2011-10-01

    Full Text Available The aim of this study was to investigate the suitability of active infrared thermography and thermometry in combination with multivariate statistical partial least squares analysis as rapid soil water content detection techniques both in the laboratory and the field. Such techniques allow fast soil water content measurements helpful in both agricultural and environmental fields. These techniques, based on the theory of heat dissipation, were tested by directly measuring temperature dynamic variation of samples after heating. For the assessment of temperature dynamic variations data were collected during three intervals (3, 6 and 10 s. To account for the presence of specific heats differences between water and soil, the analyses were regulated using slopes to linearly describe their trends. For all analyses, the best model was achieved for a 10 s slope. Three different approaches were considered, two in the laboratory and one in the field. The first laboratory-based one was centred on active infrared thermography, considered measurement of temperature variation as independent variable and reported r = 0.74. The second laboratory–based one was focused on active infrared thermometry, added irradiation as independent variable and reported r = 0.76. The in-field experiment was performed by active infrared thermometry, heating bare soil by solar irradiance after exposure due to primary tillage. Some meteorological parameters were inserted as independent variables in the prediction model, which presented r = 0.61. In order to obtain more general and wide estimations in-field a Partial Least Squares Discriminant Analysis on three classes of percentage of soil water content was performed obtaining a high correct classification in the test (88.89%. The prediction error values were lower in the field with respect to laboratory analyses. Both techniques could be used in conjunction with a Geographic Information System for obtaining detailed information

  19. Conformal Methods in General Relativity

    Science.gov (United States)

    Valiente Kroon, Juan A.

    2016-07-01

    List of symbols; Preface; 1. Introduction; Part I. Geometric Tools: 2. Differential Geometry; 3. Spacetime spinors; 4. Space spinors; 5. Conformal Geometry; Part II. General Relativity and Conformal Geometry: 6. Conformal extensions of exact solutions; 7. Asymptotic simplicity; 8. The conformal Einstein field equations; 9. Matter models; 10. Asymptotics; Part III. Methods of PDE Theory: 11. The conformal constraint equations; 12. Methods of the theory of hyperbolic differential equations; 13. Hyperbolic reductions; 14. Causality and the Cauchy problem in General Relativity; Part IV. Applications: 15. De Sitter-like spacetimes; 16. Minkowski-like spacetimes; 17. Anti-de Sitter-like spacetimes; 18. Characteristic problems for the conformal field equations; 19. Static solutions; 20. Spatial infinity; 21. Perspectives; References; Index.

  20. Enhancement of Lipase Enzyme Activity in Non-Aqueous Media through a Rapid Three Phase Partitioning and Microwave Irradiation

    Directory of Open Access Journals (Sweden)

    N. Saifuddin

    2008-01-01

    Full Text Available Three phase partitioning is fast developing as a novel bio-separation strategy with a wide range of applications including enzyme stability and enhancement of its catalytic activity. pH tuning of enzyme is now well known for use in non-aqueous systems. Tuned enzyme was prepared using a rapid drying technique of microwave dehydration (time required around 15 minutes. Further enhancement was achieved by three phase partitioning (TPP method. With optimal condition of ammonium sulphate and t-butanol, the protein appeared as an interfacial precipitate between upper t-butanol and lower aqueous phases. In this study we report the results on the lipase which has been subjected to pH tuning and TPP, which clearly indicate the remarkable increase in the initial rate of transesterification by 3.8 times. Microwave irradiation was found to increase the initial reaction rates by further 1.6 times, hence giving a combined increase in activity of about 5.4 times. Hence it is shown that microwave irradiation can be used in conjunction with other strategies (like pH tuning and TPP for enhancing initial reaction rates.

  1. A Rapid Review of the Factors Affecting Healthcare Students' Satisfaction with Small-Group, Active Learning Methods.

    Science.gov (United States)

    Kilgour, James M; Grundy, Lisa; Monrouxe, Lynn V

    2016-01-01

    PHENOMENON: Problem-based learning (PBL) and other small-group, active learning methodologies have been widely adopted into undergraduate and postgraduate healthcare curricula across the world. Although much research has examined student perceptions of these innovative teaching pedagogies, there are still questions over which factors influence these views. This article aims to identify these key elements that affect healthcare student satisfaction with PBL and other small-group learning methods, including case-based and team-based learning. A systematic rapid review method was used to identify high-quality original research papers from the healthcare education literature from between 2009 and 2014. All papers were critically appraised before inclusion in line with published guidelines. Narrative synthesis was achieved using an inductively developed, thematic framework approach. Fifty-four papers were included in the narrative synthesis. The evidence suggests that, despite an initial period of negative emotion and anxiety, the perspectives of healthcare students toward small-group, active learning methods are generally positive. The key factors influencing this satisfaction level include (a) the facilitator role, (b) tutorial structure, (c) individual student factors, (d) case authenticity, (e) increased feedback, (f) group harmony, and (g) resource availability. Insights: Student satisfaction is an important determinant of healthcare education quality, and the findings of this review may be of value in future curriculum design. The evidence described here suggests that an ideal curriculum may be based on an expert-led, hybrid PBL model.

  2. Tracing conformational changes in proteins

    OpenAIRE

    Haspel, Nurit; Moll, Mark; Baker, Matthew L; Chiu, Wah; Kavraki, Lydia E.

    2010-01-01

    Background Many proteins undergo extensive conformational changes as part of their functionality. Tracing these changes is important for understanding the way these proteins function. Traditional biophysics-based conformational search methods require a large number of calculations and are hard to apply to large-scale conformational motions. Results In this work we investigate the application of a robotics-inspired method, using backbone and limited side chain representation and a coarse grain...

  3. Conformal Fermi Coordinates

    CERN Document Server

    Dai, Liang; Schmidt, Fabian

    2015-01-01

    Fermi Normal Coordinates (FNC) are a useful frame for isolating the locally observable, physical effects of a long-wavelength spacetime perturbation. Their cosmological application, however, is hampered by the fact that they are only valid on scales much smaller than the horizon. We introduce a generalization that we call Conformal Fermi Coordinates (CFC). CFC preserve all the advantages of FNC, but in addition are valid outside the horizon. They allow us to calculate the coupling of long- and short-wavelength modes on all scales larger than the sound horizon of the cosmological fluid, starting from the epoch of inflation until today, by removing the complications of the second order Einstein equations to a large extent, and eliminating all gauge ambiguities. As an application, we present a calculation of the effect of long-wavelength tensor modes on small scale density fluctuations. We recover previous results, but clarify the physical content of the individual contributions in terms of locally measurable ef...

  4. Reflections on conformal spectra

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyungrok; Kravchuk, Petr [Walter Burke Institute for Theoretical Physics, Caltech,Pasadena, California 91125 (United States); School of Natural Sciences, Institute for Advanced Study,Princeton, New Jersey 08540 (United States); Ooguri, Hirosi [Walter Burke Institute for Theoretical Physics, Caltech,Pasadena, California 91125 (United States); School of Natural Sciences, Institute for Advanced Study,Princeton, New Jersey 08540 (United States); Kavli Institute for the Physics and Mathematics of the Universe (WPI),University of Tokyo,Kashiwa 277-8583 (Japan)

    2016-04-29

    We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions Δ{sub 0} of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite Δ{sub 0} as well as for large Δ{sub 0}. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function.

  5. Conformal (In)Equality

    Science.gov (United States)

    Hyun, Young-Hwan; Kim, Yoonbai; Lee, Seokcheon

    2018-01-01

    The current accelerating expansion of the Universe is explained either by dark energy or by modified gravity theories. Both of them can explain exactly the same background evolution of the Universe, however this degeneracy may be broken when the observation of large scale structure formation is taken into account. Two observables are parameterized by the so-called dark energy equation of state, ω and the growth index parameter, γ. From these observed parameters, one may reconstruct the model parameters of the so-called scalar-tensor gravity theory, one of the modified gravity theories. Especially, the scalar-tensor gravity theory is described both in Jordan frame and in Einstein frame. If cosmological observations are interpreted in one frame, then all of the observables should also be interpreted in that frame. This explicitly shows conformal inequality of cosmological observables.

  6. Conformal (InEquality

    Directory of Open Access Journals (Sweden)

    Hyun Young-Hwan

    2018-01-01

    Full Text Available The current accelerating expansion of the Universe is explained either by dark energy or by modified gravity theories. Both of them can explain exactly the same background evolution of the Universe, however this degeneracy may be broken when the observation of large scale structure formation is taken into account. Two observables are parameterized by the so-called dark energy equation of state, ω and the growth index parameter, γ. From these observed parameters, one may reconstruct the model parameters of the so-called scalar-tensor gravity theory, one of the modified gravity theories. Especially, the scalar-tensor gravity theory is described both in Jordan frame and in Einstein frame. If cosmological observations are interpreted in one frame, then all of the observables should also be interpreted in that frame. This explicitly shows conformal inequality of cosmological observables.

  7. Reflections on Conformal Spectra

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions Δ0 of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite Δ0 as well as for large Δ0. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function. (based on 1510.08772 with Kim & Ooguri). This seminar will be given via videolink

  8. Benzylidene-bis-(4-Hydroxycoumarin and Benzopyrano-Coumarin Derivatives: Synthesis, 1H/13C-NMR Conformational and X-ray Crystal Structure Studies and In Vitro Antiviral Activity Evaluations

    Directory of Open Access Journals (Sweden)

    Janez Plavec

    2011-07-01

    Full Text Available We report on the synthesis of 4-hydroxycoumarin dimers 1–15 bearing an aryl substituent on the central linker and fused benzopyranocoumarin derivatives 16–20 and on their in vitro broad anti-DNA and RNA virus activity evaluations. The chemical identities and structure of compounds 1–20 were deduced from their homo- and heteronuclear NMR measurements whereas the conformational properties of 5, 14 and 20 were assessed by the use of 1D difference NOE enhancements. Unequivocal proof of the stereostructure of compounds 7, 9, 16 and 18 was obtained by single crystal X-ray diffraction method. The X-ray crystal structure analysis revealed that two 4-hydroxycoumarin moieties in the 4-trifluoromethylphenyl- and 2-nitrophenyl derivatives (compounds 7 and 9, respectively are intramolecularly hydrogen-bonded between hydroxyl and carbonyl oxygen atoms. Consequently, the compounds 7 and 9 adopt conformations in which two 4-hydroxy-coumarin moieties are anti-disposed. Antiviral activity evaluation results indicated that the 4-bromobenzylidene derivative of bis-(4-hydroxycoumarin (compound 3 possesses inhibitory activity against HSV-1 (KOS, HSV-2 (G, vaccinia virus and HSV-1 TK- KOS (ACVr at a concentration of 9–12 μM and at a minimum cytotoxic concentration (MCC greater than 20 μM. Compounds 4–6, 8, and 20 were active against feline herpes virus (50% effective concentration, EC50 = 5–8.1 μM, that is at a 4-7-fold lower concentration than the MCC.

  9. A rapid method for testing in vivo the susceptibility of different strains of Trypanosoma cruzi to active chemotherapeutic agents

    Directory of Open Access Journals (Sweden)

    Leny S. Filardi

    1984-06-01

    Full Text Available A method is described which permits to determine in vivo an in a short period of time (4-6 hours the sensitivity of T. cruzo strains to known active chemotherapeutic agents. By using resistant- and sensitive T. cruzi stains a fairly good correlation was observed between the results obtained with this rapid method (which detects activity against the circulating blood forms and those obtained with long-term schedules which involve drug adminstration for at least 20 consecutive days and a prolonged period of assessment. This method may be used to characterize susceptibility to active drugs used clinically, provide infomation on the specific action against circulating trypomastigotes and screen active compounds. Differences in the natural susceptibility of Trypanosoma cruzi strains to active drugs have been already reported using different criteria, mostly demanding long-term study of the animal (Hauschka, 1949; Bock, Gonnert & Haberkorn, 1969; Brener, Costa & Chiari, 1976; Andrade & Figueira, 1977; Schlemper, 1982. In this paper we report a method which detects in 4-6 hours the effect of drugs on bloodstream forms in mice with established T. cruzi infections. The results obtained with this method show a fairly good correlation with those obtained by prolonged treatment schedules used to assess the action of drugs in experimental Chagas' disease and may be used to study the sensitivity of T. cruzi strains to active drugs.No presente trabalho descreve-se um metodo que permite determinar in vivo e em curto espaço de tempo (4-6 horas a sensibilidade de cepas de T. cruzi a agentes terapeuticos ativos na doença de Chagas. Usando-se cepas sensíveis e resistentes aos medicamentos foi possível observar uma boa correlação entre os resultados obtidos com o método rápido (que detecta atividade contra as formas circulantes do parasita e aqueles obtidos com esquema de acao prolongada que envolve a administração da droga por 20 dias e posterior avalia

  10. Fusion activity of influenza virus PR8/34 correlates with a temperature-induced conformational change within the hemagglutinin ectodomain detected by photochemical labeling

    Energy Technology Data Exchange (ETDEWEB)

    Brunner, J.; Zugliani, C. (Swiss Federal Inst. of Tech., Zuerich (Switzerland)); Mischler, R. (Swiss Serum and Vaccine Inst., Bern (Switzerland))

    1991-03-05

    Fusion of influenza viruses with membranes is catalyzed by the viral spike protein hemagglutinin (HA). Under mildly acidic conditions ({approximately}pH 5) this protein undergoes a conformational change that triggers the exposure of the fusion peptide, the hydrophobic N-terminal segment of the HA2 polypeptide chain. Insertion of this segment into the target membrane (or viral membrane ) is likely to represent a key step along the fusion pathway, but the details are far from being clear. The photoreactive phospholipid 1-palmitoyl-2-(11-(4-(3-(trifluoromethyl)diazirinyl)phenyl)(2-{sup 3}H)undecanoyl)-sn-glycero-3-phosphocholine (({sup 3}H)PTPC/11), inserted into the bilayer of large unilamellar vesicles (LUVs), allowed the authors to investigate both the interaction of viruses with the vesicles under perfusion conditions and the fusion process itself occurring at elevated temperatures only. Despite the observed binding of viruses to LUVs at pH 5 and 0C, labeling of HA2 was very weak. They have studied also the effect of temperature on the acid-induced (pH 5) interaction of bromelain-solubilized HA (BHA) with vesicles.

  11. Rapid mixing kinetic techniques.

    Science.gov (United States)

    Martin, Stephen R; Schilstra, Maria J

    2013-01-01

    Almost all of the elementary steps in a biochemical reaction scheme are either unimolecular or bimolecular processes that frequently occur on sub-second, often sub-millisecond, time scales. The traditional approach in kinetic studies is to mix two or more reagents and monitor the changes in concentrations with time. Conventional spectrophotometers cannot generally be used to study reactions that are complete within less than about 20 s, as it takes that amount of time to manually mix the reagents and activate the instrument. Rapid mixing techniques, which generally achieve mixing in less than 2 ms, overcome this limitation. This chapter is concerned with the use of these techniques in the study of reactions which reach equilibrium; the application of these methods to the study of enzyme kinetics is described in several excellent texts (Cornish-Bowden, Fundamentals of enzyme kinetics. Portland Press, 1995; Gutfreund, Kinetics for the life sciences. Receptors, transmitters and catalysis. Cambridge University Press, 1995).There are various ways to monitor changes in concentration of reactants, intermediates and products after mixing, but the most common way is to use changes in optical signals (absorbance or fluorescence) which often accompany reactions. Although absorbance can sometimes be used, fluorescence is often preferred because of its greater sensitivity, particularly in monitoring conformational changes. Such methods are continuous with good time resolution but they seldom permit the direct determination of the concentrations of individual species. Alternatively, samples may be taken from the reaction volume, mixed with a chemical quenching agent to stop the reaction, and their contents assessed by techniques such as HPLC. These methods can directly determine the concentrations of different species, but are discontinuous and have a limited time resolution.

  12. Rapid Assessment of Distribution of Wildlife and Human Activities for Prioritizing Conservation Actions in a Patagonian Landscape.

    Science.gov (United States)

    Rivas, Lorena F; Novaro, Andrés J; Funes, Martín C; Walker, R Susan

    2015-01-01

    Large landscapes encompassing reserves and areas with other human uses are necessary for conservation of many species. Generating information for conservation planning over such landscapes may be expensive and time-consuming, though resources for conservation are generally limited and conservation is often urgent. We developed a sign-based occupancy survey to help prioritize conservation interventions by simultaneously assessing the distribution of 3 species, the lesser rhea, guanaco, and mara, and their association with human activities in a 20,000-km2 landscape in the northern Patagonian steppe. We used a single-season occupancy model with spatial rather than temporal replication of surveys in order to reduce costs of multiple visits to sites. We used covariates related to detectability, environmental factors, and different human activities to identify the most plausible models of occupancy, and calculated importance weights of covariates from these models to evaluate relative impacts of human activities on each species. Abundance of goats had the strongest negative association with lesser rheas and guanacos, and road density with maras. With six months of fieldwork, our results provided initial hypotheses for adaptive conservation interventions for each species. Addressing high livestock densities for rheas and guanacos, poaching by urban hunters for all three species, and hunting by rural people for rheas are priorities for conservation in this landscape. Our methodology provided new insights into the responses of these species, although low detection probabilities for maras indicate that the sampling scheme should be altered for future monitoring of this species. This method may be adapted for any large landscape where a rapid, objective means for prioritizing conservation actions on multiple species is needed and data are scarce.

  13. Rapid synthesis of biocompatible silver nanoparticles using aqueous extract of Rosa damascena petals and evaluation of their anticancer activity.

    Science.gov (United States)

    Venkatesan, Balaji; Subramanian, Vimala; Tumala, Anusha; Vellaichamy, Elangovan

    2014-09-01

    To optimize the process parameters involved in the green synthesis of silver nanoparticles (G-SNPs) by aqueous extract of Rosa damascena petals and to evaluate the biocompatibility and anti cancer activity of the synthesized silver nanoparticles against human lung adenocarcinoma (A549). The process variables that include concentration of extract, mixing ratio of reactants, silver salt concentration and interaction time were analyzed. The compatibility of the G-SNPs was verified by incubating with erythrocytes and the anticancer property of the G-SNPs against A549 cells was performed by MTT assay. Formation of G-SNPs was confirmed by the visual change in the colour of the reaction mixture from pale yellow to brown yellow. Surface plasmon resonance of synthesized G-SNPs was observed at 420 nm; the size of G-SNPs were analyzed by DLS and found to be in the range of (84.00±10.08) nm. Field emission scanning electron microscope and high resolution transmission electron microscopy analysis confirmed that the G-SNPs were fairly spherical. Fourier transform infrared spectroscopy spectroscopy and X-ray diffraction revealed the characteristic peaks of G-SNPs. Energy dispersive X-ray analysis showed a signal of silver around 3 keV. The synthesized G-SNPs exhibited anticancer activity as evidenced by the MTT assay. IC50 value of G-SNPs was found to be 80 μg/mL. The results of the present study suggest that G-SNPs can be synthesized rapidly within first minute of the reaction; they are biocompatible and possess anticancer activity against human lung adenocarcinoma. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  14. Ship-borne measurements of microbial enzymatic activity: A rapid biochemical indicator for microbial water quality monitoring

    Science.gov (United States)

    Stadler, Philipp; Loken, Luke; Crawford, John; Schramm, Paul; Sorsa, Kirsti; Kuhn, Catherine; Savio, Domenico; Striegl, Rob; Butman, David; Stanley, Emily; Farnleitner, Andreas H.; Zessner, Matthias

    2017-04-01

    Contamination of aquatic ecosystems by human and animal wastes is a global concern for water quality. Disclosing fate and transport processes of fecal indicator organism (FIO) in large water bodies is a big challenge due to material intensive and time consuming methods used in microbiological water quality monitoring. In respect of utilization of large surface water resources there is a dearth of rapid microbiological methods that allow a near-real time health related water quality monitoring to be implemented into early warning systems. The detection of enzymatic activities has been proposed as a rapid surrogate for microbiological pollution monitoring of water and water resources (Cabral, 2010; Farnleitner et al., 2001, 2002). Methods such as the beta-D-Glucuronidase assay (GLUC), targeting FIO such as E. coli, were established. New automated enzymatic assays have been implemented during the last years into on-site monitoring stations, ranging from ground- to surface waters (Ryzinska-Paier et al., 2014; Stadler et al., 2017, 2016). While these automated enzymatic methods cannot completely replace assays for culture-based FIO enumeration, they yielded significant information on pollution events and temporal dynamics on a catchment specific basis, but were restricted to stationary measurements. For the first time we conducted ship-borne and automated measurements of enzymatic GLUC activity on large fresh water bodies, including the Columbia River, the Mississippi River and Lake Mendota. Not only are automated enzymatic assays technically feasible from a mobile vessel, but also can be used to localize point sources of potential microbial fecal contamination, such as tributaries or storm drainages. Spatial and temporal patterns of enzymatic activity were disclosed and the habitat specific correlation with microbiological standard assays for FIO determined due to reference samples. The integration of rapid and automated enzymatic assays into well-established systems

  15. Understanding Modern Magnets through Conformal Mapping

    Energy Technology Data Exchange (ETDEWEB)

    Halbach, K.

    1989-10-27

    none at all. When I started getting involved in work for which conformal mapping seemed to be a powerful tool, I did not think that I would ever be able to use that technique successfully because it seemed to require a nearly encyclopedic memory, an impression that was strengthened when I saw H.Kober's Dictionary of Conformal Representations (ref. 1). This attitude changed when I started to realize that beyond the basics of the theory of a function of a complex variable, I needed to know only about a handful of conformal maps and procedures. Consequently, my second goal for this talk is to: (2) Show that in most cases conformal mapping functions can be obtained by formulating the underlying physics appropriately. This means particularly that encyclopedic knowledge of conformal maps is not necessary for successful use of conformal mapping techniques. To demonstrate these facts I have chosen examples from an area of physics/engineering in which I am active, namely accelerator physics. In order to do that successfully I start with a brief introduction into high energy charged particle storage ring technology, even though not all examples used in this paper to elucidate my points come directly from this particular field of accelerator technology. This is followed by a brief summary of the most important properties of functions of a complex variable. When reading this introduction into the relevant mathematics, the reader needs to keep in mind that this is not a mathematics essay, but a demonstration how beautiful and powerful, but not always appreciated, mathematics can be if used by a physicist or engineer to solve some real life problems.

  16. Replacement between conformity and counter-conformity in consumption decisions.

    Science.gov (United States)

    Chou, Ting-Jui; Chang, En-Chung; Dai, Qi; Wong, Veronica

    2013-02-01

    This study assessed, in a Chinese context, how self-esteem interacts with perceived similarity and uniqueness to yield cognitive dissonance, and whether the dissonance leads to self-reported conformity or counter-conformity behavior. Participants were 408 respondents from 4 major Chinese cities (M age = 33.0 yr., SD = 4.3; 48% men). Self-perceptions of uniqueness, similarity, cognitive dissonance, self-esteem and need to behave in conformity or counter-conformity were measured. A theoretical model was assessed in four situations, relating the ratings of self-esteem and perceived similarity/uniqueness to the way other people at a wedding were dressed, and the resultant cognitive dissonance and conformity/ counter-conformity behavior. Regardless of high or low self-esteem, all participants reported cognitive dissonance when they were told that they were dressed extremely similarly to or extremely differently from the other people attending the wedding. However, the conforming/counter-conforming strategies used by participants to resolve the cognitive dissonance differed. When encountering dissonance induced by the perceived extreme uniqueness of dress, participants with low self-esteem tended to say they would dress next time so as to conform with the way others were dressed, while those with high self-esteem indicated they would continue their counter-conformity in attire. When encountering dissonance induced by the perceived extreme similarity to others, both those with high and low self-esteem tended to say they would dress in an unorthodox manner to surprise other people in the future.

  17. Recent advancements in conformal gravity

    Science.gov (United States)

    O'Brien, James G.; Chaykov, Spasen S.; Dentico, Jeremy; Stulge, Modestas; Stefanski, Brian; Moss, Robert J.

    2017-05-01

    In recent years, due to the lack of direct observed evidence of cold dark matter, coupled with the shrinking parameter space to search for new dark matter particles, there has been increased interest in Alternative Gravitational theories. This paper, addresses three recent advances in conformal gravity, a fourth order renormalizable metric theory of gravitation originally formulated by Weyl, and later advanced by Mannheim and Kazanas. The first section of the paper applies conformal gravity to the rotation curves of the LITTLE THINGS survey, extending the total number of rotation curves successfully fit by conformal gravity to well over 200 individual data sets without the need for additional dark matter. Further, in this rotation curve study, we show how MOND and conformal gravity compare for each galaxy in the sample. Second, we look at the original Zwicky problem of applying the virial theorem to the Coma cluster in order to get an estimate for the cluster mass. However, instead of using the standard Newtonian potential, here we use the weak field approximation of conformal gravity. We show that in the conformal case we can get a much smaller mass estimate and thus there is no apparent need to include dark matter. We then show that this calculation is in agreement with the observational data from other well studied clusters. Last, we explore the calculation of the deflection of starlight through conformal gravity, as a first step towards applying conformal gravity to gravitaitonal lensing.

  18. Solvent Induced Conformational Kinetics (SICK)

    NARCIS (Netherlands)

    Jonkman, Leffert; Kommandeur, Jan

    1970-01-01

    Specific conformations of molecules may be induced by the solvent when a large free volume is associated with the oonformational change. The conformational energy barrier is then a property of the solvent, rather than of the molecule. Such effects are reported for several substituted

  19. Counselor Identity: Conformity or Distinction?

    Science.gov (United States)

    McLaughlin, Jerry E.; Boettcher, Kathryn

    2009-01-01

    The authors explore 3 debates in other disciplines similar to counseling's identity debate in order to learn about common themes and outcomes. Conformity, distinction, and cohesion emerged as common themes. They conclude that counselors should retain their distinctive, humanistic approach rather than conforming to the dominant, medical approach.

  20. Rapid Biosynthesis of Gold Nanoparticles by the Extracellular Secretion of Bacillus niabensis 45: Characterization and Antibiofilm Activity

    Directory of Open Access Journals (Sweden)

    Yumei Li

    2016-01-01

    Full Text Available The present study demonstrated that the extracellular biosynthesis of gold nanoparticles (GNPs using B. niabensis 45 may be mediated by a cyclic peptide (P2. The molecular weight of P2 was determined to be about 1122 Da by MALDI-TOF-MS and ESI-MS. A novel protocol for rapid biosynthesis of GNPs using P2 was developed. The results showed that GNP synthesis could be completed in a wide range of temperatures (40–100°C and pH (6.0–10.0 within few minutes when 9 mL of P2 (2 mg/mL and 1 mL of HAuCl4 solution (2 mM were mixed together. The synthesized GNPs were further characterized. Energy dispersive spectroscopy (EDS and X-ray diffraction (XRD analysis confirmed the presence of elemental gold and crystalline structure of the GNPs, respectively. Scanning electron microscopy (SEM and transmission electron microscopy (TEM revealed the formation of spherical metallic GNPs. The size distribution of GNPs calculated using ImageJ software was found to be 10–20 nm. And these GNPs showed excellent antibiofilm activity against Pseudomonas aeruginosa PAO1 and Staphylococcus aureus ATCC25923. The results revealed microbial cyclic peptides could be used as synthesis of GNPs which had potent antibiofilm potential.

  1. HIV-1 Tat activates neuronal ryanodine receptors with rapid induction of the unfolded protein response and mitochondrial hyperpolarization.

    Directory of Open Access Journals (Sweden)

    John P Norman

    Full Text Available Neurologic disease caused by human immunodeficiency virus type 1 (HIV-1 is ultimately refractory to highly active antiretroviral therapy (HAART because of failure of complete virus eradication in the central nervous system (CNS, and disruption of normal neural signaling events by virally induced chronic neuroinflammation. We have previously reported that HIV-1 Tat can induce mitochondrial hyperpolarization in cortical neurons, thus compromising the ability of the neuron to buffer calcium and sustain energy production for normal synaptic communication. In this report, we demonstrate that Tat induces rapid loss of ER calcium mediated by the ryanodine receptor (RyR, followed by the unfolded protein response (UPR and pathologic dilatation of the ER in cortical neurons in vitro. RyR antagonism attenuated both Tat-mediated mitochondrial hyperpolarization and UPR induction. Delivery of Tat to murine CNS in vivo also leads to long-lasting pathologic ER dilatation and mitochondrial morphologic abnormalities. Finally, we performed ultrastructural studies that demonstrated mitochondria with abnormal morphology and dilated endoplasmic reticulum (ER in brain tissue of patients with HIV-1 inflammation and neurodegeneration. Collectively, these data suggest that abnormal RyR signaling mediates the neuronal UPR with failure of mitochondrial energy metabolism, and is a critical locus for the neuropathogenesis of HIV-1 in the CNS.

  2. Nebulization of active pharmaceutical ingredients with the eFlow(®) rapid: impact of formulation variables on aerodynamic characteristics.

    Science.gov (United States)

    Beck-Broichsitter, Moritz; Prüfer, Nadine; Oesterheld, Nina; Seeger, Werner; Schmehl, Thomas

    2014-08-01

    Nebulization of active pharmaceutical ingredient (API) solutions is a well-established means to achieve pulmonary drug deposition. The current study identified the impact of formulation variables on the aerosolization performance of the eFlow(®) rapid with special respect to optimized lung application. API formulations (including excipient-supplemented samples) were investigated for physicochemical properties, then nebulized using vibrating-mesh technology. The generated aerosol clouds were analyzed by laser diffraction. Aerosol deposition characteristics in the human respiratory tract were estimated using an algebraic model. Remarkable effects on aerosolization performance [i.e., mass median aerodynamic diameter (MMAD)] of API solutions were obtained when the sample conductivity (by API concentration and type, sodium chloride addition) and dynamic viscosity (by application of sucrose and poly(ethylene glycol) 200) were elevated. A similar influence was observed for a decline in surface tension (by ethanol addition). Thus, a defined adjustment of formulation parameters allowed for a decrease of the MMAD from ∼ 8.0 μm to values as small as ∼ 3.5 μm. Consequently, the pattern and efficiency of aerosol deposition in the human respiratory tract were improved. In conclusion, identification of physicochemical variables and their way of influencing vibrating-mesh nebulization has been provided to deliver a platform for tailoring aerosol characteristics and thus, advancing pulmonary therapy. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  3. Photosynthetic activity and proteomic analysis highlights the utilization of atmospheric CO2 by Ulva prolifera (Chlorophyta) for rapid growth.

    Science.gov (United States)

    Huan, Li; Gu, Wenhui; Gao, Shan; Wang, Guangce

    2016-12-01

    Free-floating Ulva prolifera is one of the causative species of green tides. When green tides occur, massive mats of floating U. prolifera thalli accumulate rapidly in surface waters with daily growth rates as high as 56%. The upper thalli of the mats experience environmental changes such as the change in carbon source, high salinity, and desiccation. In this study, the photosynthetic performances of PSI and PSII in U. prolifera thalli exposed to different atmospheric carbon dioxide (CO2 ) levels were measured. Changes in photosynthesis within salinity treatments and dehydration under different CO2 concentrations were also analyzed. The results showed that PSII activity was enhanced as CO2 increased, suggesting that CO2 assimilation was enhanced and U. prolifera thalli can utilize CO2 in the atmosphere directly, even when under moderate stress. In addition, changes in the proteome of U. prolifera in response to salt stress were investigated. Stress-tolerance proteins appeared to have an important role in the response to salinity stress, whereas the abundance of proteins related to metabolism showed no significant change under low salinity treatments. These findings may be one of the main reasons for the extremely high growth rate of free-floating U. prolifera when green tides occur. © 2016 Phycological Society of America.

  4. Preliminary test of the LFA rapid evaluation of activity in lupus (LFA-REAL): an efficient outcome measure correlates with validated instruments

    OpenAIRE

    Askanase, Anca; Li, Xiaoqing; Pong, Avery; Shum, Katrina; Kamp, Stan; Carthen, Fredonna; Aberle, Teresa; Hanrahan, Leslie; Daly, Paola; Giles, Jon; Merrill, Joan T

    2015-01-01

    Objective Current disease activity measures for systemic lupus erythematosus (SLE) are difficult to score or interpret and problematic for use in clinical practice. Lupus Foundation of America (LFA)-Rapid Evaluation of Activity in Lupus (REAL) is a pilot application composed of anchored visual analogue scores (0?100?mm each) for each organ affected by lupus. This study evaluated the use of LFA-REAL in capturing SLE disease activity. Methods In a preliminary test of LFA-REAL, this simplified, ...

  5. The Role of Non-Rapid Eye Movement Slow-Wave Activity in Prefrontal Metabolism across Young and Middle Age Adults

    OpenAIRE

    Wilckens, K.A.; Aizenstein, H J; Nofzinger, E.A.; James, J. A.; Hasler, B.P.; Rosario-Rivera, B.L.; Franzen, P; Germain, A.; Hall, M. H.; Kupfer, D.J.; Price, J C.; Siegle, G.J.; Buysse, D. J.

    2016-01-01

    Electroencephalographic slow-wave activity (0.5���4 Hz) during non rapid-eye-movement (NREM) sleep is a marker for cortical reorganization, particularly within the prefrontal cortex. Greater slow-wave activity during sleep may promote greater waking prefrontal metabolic rate, and in turn, executive function. However, this process may be affected by age. Here we examined whether greater NREM slow-wave activity was associated with higher prefrontal metabolism during wakefulness and whether this...

  6. A Novel, Low-Cost Conformable Lander Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary focus of this activity will be to outline a preliminary mechanical design for this conforming lander. Salient issues to be worked include (1) determining...

  7. On the Systematic Conformance Check of Software Artefacts

    NARCIS (Netherlands)

    van Dijk, H.W.; Graaf, Bas; Boerman, Rob; Morrison, R.; Oquendo, F.

    In this paper we present a systematic check of the conformance of the implemented and the intended software architecture. Nowadays industry is confronted with rapidly evolving embedded systems. In order to effectively reuse design artefacts such as requirements, architectural views and analysis, as

  8. Meat Feeding Restricts Rapid Cold Hardening Response and Increases Thermal Activity Thresholds of Adult Blow Flies, Calliphora vicina (Diptera: Calliphoridae.

    Directory of Open Access Journals (Sweden)

    Paul C Coleman

    Full Text Available Virtually all temperate insects survive the winter by entering a physiological state of reduced metabolic activity termed diapause. However, there is increasing evidence that climate change is disrupting the diapause response resulting in non-diapause life stages encountering periods of winter cold. This is a significant problem for adult life stages in particular, as they must remain mobile, periodically feed, and potentially initiate reproductive development at a time when resources should be diverted to enhance stress tolerance. Here we present the first evidence of protein/meat feeding restricting rapid cold hardening (RCH ability and increasing low temperature activity thresholds. No RCH response was noted in adult female blow flies (Calliphora vicina Robineau-Desvoidy fed a sugar, water and liver (SWL diet, while a strong RCH response was seen in females fed a diet of sugar and water (SW only. The RCH response in SW flies was induced at temperatures as high as 10°C, but was strongest following 3h at 0°C. The CTmin (loss of coordinated movement and chill coma (final appendage twitch temperature of SWL females (-0.3 ± 0.5°C and -4.9 ± 0.5°C, respectively was significantly higher than for SW females (-3.2 ± 0.8°C and -8.5 ± 0.6°C. We confirmed this was not directly the result of altered extracellular K+, as activity thresholds of alanine-fed adults were not significantly different from SW flies. Instead we suggest the loss of cold tolerance is more likely the result of diverting resource allocation to egg development. Between 2009 and 2013 winter air temperatures in Birmingham, UK, fell below the CTmin of SW and SWL flies on 63 and 195 days, respectively, suggesting differential exposure to chill injury depending on whether adults had access to meat or not. We conclude that disruption of diapause could significantly impact on winter survival through loss of synchrony in the timing of active feeding and reproductive development with

  9. Recursion Relations for Conformal Blocks

    CERN Document Server

    Penedones, João; Yamazaki, Masahito

    2016-09-12

    In the context of conformal field theories in general space-time dimension, we find all the possible singularities of the conformal blocks as functions of the scaling dimension $\\Delta$ of the exchanged operator. In particular, we argue, using representation theory of parabolic Verma modules, that in odd spacetime dimension the singularities are only simple poles. We discuss how to use this information to write recursion relations that determine the conformal blocks. We first recover the recursion relation introduced in 1307.6856 for conformal blocks of external scalar operators. We then generalize this recursion relation for the conformal blocks associated to the four point function of three scalar and one vector operator. Finally we specialize to the case in which the vector operator is a conserved current.

  10. Monitoring of β-d-Galactosidase Activity as a Surrogate Parameter for Rapid Detection of Sewage Contamination in Urban Recreational Water

    Directory of Open Access Journals (Sweden)

    Ingun Tryland

    2016-02-01

    Full Text Available Simple, automated methods are required for rapid detection of wastewater contamination in urban recreational water. The activity of the enzyme β-d-galactosidase (GAL can rapidly (<2 h be measured by field instruments, or a fully automated instrument, and was evaluated as a potential surrogate parameter for estimating the level of fecal contamination in urban waters. The GAL-activity in rivers, affected by combined sewer overflows, increased significantly during heavy rainfall, and the increase in GAL-activity correlated well with the increase in fecal indicator bacteria. The GAL activity in human feces (n = 14 was high (mean activity 7 × 107 ppb MU/hour and stable (1 LOG10 variation, while the numbers of Escherichia coli and intestinal enterococci varied by >5 LOG10. Furthermore, the GAL-activity per gram feces from birds, sheep and cattle was 2–3 LOG10 lower than the activity from human feces, indicating that high GAL-activity in water may reflect human fecal pollution more than the total fecal pollution. The rapid method can only be used to quantify high levels of human fecal pollution, corresponding to about 0.1 mg human feces/liter (or 103 E. coli/100 mL, since below this limit GAL-activity from non-fecal environmental sources may interfere.

  11. NMR studies of dynamic biomolecular conformational ensembles.

    Science.gov (United States)

    Torchia, Dennis A

    2015-02-01

    Multidimensional heteronuclear NMR approaches can provide nearly complete sequential signal assignments of isotopically enriched biomolecules. The availability of assignments together with measurements of spin relaxation rates, residual spin interactions, J-couplings and chemical shifts provides information at atomic resolution about internal dynamics on timescales ranging from ps to ms, both in solution and in the solid state. However, due to the complexity of biomolecules, it is not possible to extract a unique atomic-resolution description of biomolecular motions even from extensive NMR data when many conformations are sampled on multiple timescales. For this reason, powerful computational approaches are increasingly applied to large NMR data sets to elucidate conformational ensembles sampled by biomolecules. In the past decade, considerable attention has been directed at an important class of biomolecules that function by binding to a wide variety of target molecules. Questions of current interest are: "Does the free biomolecule sample a conformational ensemble that encompasses the conformations found when it binds to various targets; and if so, on what time scale is the ensemble sampled?" This article reviews recent efforts to answer these questions, with a focus on comparing ensembles obtained for the same biomolecules by different investigators. A detailed comparison of results obtained is provided for three biomolecules: ubiquitin, calmodulin and the HIV-1 trans-activation response RNA. Published by Elsevier B.V.

  12. Conformational Dynamics and Allostery in Pyruvate Kinase.

    Science.gov (United States)

    Donovan, Katherine A; Zhu, Shaolong; Liuni, Peter; Peng, Fen; Kessans, Sarah A; Wilson, Derek J; Dobson, Renwick C J

    2016-04-22

    Pyruvate kinase catalyzes the final step in glycolysis and is allosterically regulated to control flux through the pathway. Two models are proposed to explain how Escherichia coli pyruvate kinase type 1 is allosterically regulated: the "domain rotation model" suggests that both the domains within the monomer and the monomers within the tetramer reorient with respect to one another; the "rigid body reorientation model" proposes only a reorientation of the monomers within the tetramer causing rigidification of the active site. To test these hypotheses and elucidate the conformational and dynamic changes that drive allostery, we performed time-resolved electrospray ionization mass spectrometry coupled to hydrogen-deuterium exchange studies followed by mutagenic analysis to test the activation mechanism. Global exchange experiments, supported by thermostability studies, demonstrate that fructose 1,6-bisphosphate binding to the allosteric domain causes a shift toward a globally more dynamic ensemble of conformations. Mapping deuterium exchange to peptides within the enzyme highlight site-specific regions with altered conformational dynamics, many of which increase in conformational flexibility. Based upon these and mutagenic studies, we propose an allosteric mechanism whereby the binding of fructose 1,6-bisphosphate destabilizes an α-helix that bridges the allosteric and active site domains within the monomeric unit. This destabilizes the β-strands within the (β/α)8-barrel domain and the linked active site loops that are responsible for substrate binding. Our data are consistent with the domain rotation model but inconsistent with the rigid body reorientation model given the increased flexibility at the interdomain interface, and we can for the first time explain how fructose 1,6-bisphosphate affects the active site. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Conformational Dynamics and Allostery in Pyruvate Kinase*

    Science.gov (United States)

    Donovan, Katherine A.; Zhu, Shaolong; Liuni, Peter; Peng, Fen; Kessans, Sarah A.; Wilson, Derek J.

    2016-01-01

    Pyruvate kinase catalyzes the final step in glycolysis and is allosterically regulated to control flux through the pathway. Two models are proposed to explain how Escherichia coli pyruvate kinase type 1 is allosterically regulated: the “domain rotation model” suggests that both the domains within the monomer and the monomers within the tetramer reorient with respect to one another; the “rigid body reorientation model” proposes only a reorientation of the monomers within the tetramer causing rigidification of the active site. To test these hypotheses and elucidate the conformational and dynamic changes that drive allostery, we performed time-resolved electrospray ionization mass spectrometry coupled to hydrogen-deuterium exchange studies followed by mutagenic analysis to test the activation mechanism. Global exchange experiments, supported by thermostability studies, demonstrate that fructose 1,6-bisphosphate binding to the allosteric domain causes a shift toward a globally more dynamic ensemble of conformations. Mapping deuterium exchange to peptides within the enzyme highlight site-specific regions with altered conformational dynamics, many of which increase in conformational flexibility. Based upon these and mutagenic studies, we propose an allosteric mechanism whereby the binding of fructose 1,6-bisphosphate destabilizes an α-helix that bridges the allosteric and active site domains within the monomeric unit. This destabilizes the β-strands within the (β/α)8-barrel domain and the linked active site loops that are responsible for substrate binding. Our data are consistent with the domain rotation model but inconsistent with the rigid body reorientation model given the increased flexibility at the interdomain interface, and we can for the first time explain how fructose 1,6-bisphosphate affects the active site. PMID:26879751

  14. Neurobiological correlates of social conformity and independence during mental rotation.

    Science.gov (United States)

    Berns, Gregory S; Chappelow, Jonathan; Zink, Caroline F; Pagnoni, Giuseppe; Martin-Skurski, Megan E; Richards, Jim

    2005-08-01

    When individual judgment conflicts with a group, the individual will often conform his judgment to that of the group. Conformity might arise at an executive level of decision making, or it might arise because the social setting alters the individual's perception of the world. We used functional magnetic resonance imaging and a task of mental rotation in the context of peer pressure to investigate the neural basis of individualistic and conforming behavior in the face of wrong information. Conformity was associated with functional changes in an occipital-parietal network, especially when the wrong information originated from other people. Independence was associated with increased amygdala and caudate activity, findings consistent with the assumptions of social norm theory about the behavioral saliency of standing alone. These findings provide the first biological evidence for the involvement of perceptual and emotional processes during social conformity.

  15. Ras conformational switching: simulating nucleotide-dependent conformational transitions with accelerated molecular dynamics.

    Directory of Open Access Journals (Sweden)

    Barry J Grant

    2009-03-01

    Full Text Available Ras mediates signaling pathways controlling cell proliferation and development by cycling between GTP- and GDP-bound active and inactive conformational states. Understanding the complete reaction path of this conformational change and its intermediary structures is critical to understanding Ras signaling. We characterize nucleotide-dependent conformational transition using multiple-barrier-crossing accelerated molecular dynamics (aMD simulations. These transitions, achieved for the first time for wild-type Ras, are impossible to observe with classical molecular dynamics (cMD simulations due to the large energetic barrier between end states. Mapping the reaction path onto a conformer plot describing the distribution of the crystallographic structures enabled identification of highly populated intermediate structures. These structures have unique switch orientations (residues 25-40 and 57-75 intermediate between GTP and GDP states, or distinct loop3 (46-49, loop7 (105-110, and alpha5 C-terminus (159-166 conformations distal from the nucleotide-binding site. In addition, these barrier-crossing trajectories predict novel nucleotide-dependent correlated motions, including correlations of alpha2 (residues 66-74 with alpha3-loop7 (93-110, loop2 (26-37 with loop10 (145-151, and loop3 (46-49 with alpha5 (152-167. The interconversion between newly identified Ras conformations revealed by this study advances our mechanistic understanding of Ras function. In addition, the pattern of correlated motions provides new evidence for a dynamic linkage between the nucleotide-binding site and the membrane interacting C-terminus critical for the signaling function of Ras. Furthermore, normal mode analysis indicates that the dominant collective motion that occurs during nucleotide-dependent conformational exchange, and captured in aMD (but absent in cMD simulations, is a low-frequency motion intrinsic to the structure.

  16. Imaging of conformational changes

    Energy Technology Data Exchange (ETDEWEB)

    Michl, Josef [Univ. of Colorado, Boulder, CO (United States)

    2016-03-13

    Control of intramolecular conformational change in a small number of molecules or even a single one by an application of an outside electric field defined by potentials on nearby metal or dielectric surfaces has potential applications in both 3-D and 2-D nanotechnology. Specifically, the synthesis, characterization, and understanding of designed solids with controlled built-in internal rotational motion of a dipole promises a new class of materials with intrinsic dielectric, ferroelectric, optical and optoelectronic properties not found in nature. Controlled rotational motion is of great interest due to its expected utility in phenomena as diverse as transport, current flow in molecular junctions, diffusion in microfluidic channels, and rotary motion in molecular machines. A direct time-resolved observation of the dynamics of motion on ps or ns time scale in a single molecule would be highly interesting but is also very difficult and has yet to be accomplished. Much can be learned from an easier but still challenging comparison of directly observed initial and final orientational states of a single molecule, which is the basis of this project. The project also impacts the understanding of surface-enhanced Raman spectroscopy (SERS) and single-molecule spectroscopic detection, as well as the synthesis of solid-state materials with tailored properties from designed precursors.

  17. Conformal solids and holography

    Science.gov (United States)

    Esposito, A.; Garcia-Saenz, S.; Nicolis, A.; Penco, R.

    2017-12-01

    We argue that a SO( d) magnetic monopole in an asymptotically AdS space-time is dual to a d-dimensional strongly coupled system in a solid state. In light of this, it would be remiss of us not to dub such a field configuration solidon. In the presence of mixed boundary conditions, a solidon spontaneously breaks translations (among many other symmetries) and gives rise to Goldstone excitations on the boundary — the phonons of the solid. We derive the quadratic action for the boundary phonons in the probe limit and show that, when the mixed boundary conditions preserve conformal symmetry, the longitudinal and transverse sound speeds are related to each other as expected from effective field theory arguments. We then include backreaction and calculate the free energy of the solidon for a particular choice of mixed boundary conditions, corresponding to a relevant multi-trace deformation of the boundary theory. We find such free energy to be lower than that of thermal AdS. This suggests that our solidon undergoes a solid-to-liquid first order phase transition by melting into a Schwarzschild-AdS black hole as the temperature is raised.

  18. Experiences of pressure to conform in postgraduate medical education.

    Science.gov (United States)

    Grendar, Jan; Beran, Tanya; Oddone-Paolucci, Elizabeth

    2018-01-03

    Perception of pressure to conform prevents learners from actively participating in educational encounters. We expected that residents would report experiencing different amounts of pressure to conform in a variety of educational settings. A total of 166 residents completed questionnaires about the frequency of conformity pressure they experience across 14 teaching and clinical settings. We examined many individual characteristics such as their age, sex, international student status, level of education, and tolerance of ambiguity; and situational characteristics such as residency program, type of learning session, status of group members, and type of rotation to determine when conformity pressure is most likely to occur. The majority of participants (89.8%) reported pressure to conform at least sometimes in at least one educational or clinical setting. Residents reported higher rates of conformity during informal, rather than formal, teaching sessions, p < .001. Also, pressure was greater when residents interacted with higher status group members, but not with the same or lower level status members, p < .001. Effect sizes were in the moderate range. The findings suggest that most residents do report feeling pressure to conform in their residency settings. This result is consistent with observations of medical students, nursing students, and clerks conforming in response to inaccurate information within experimental studies. Perception of pressure is associated with the setting rather than the trainee personal characteristics.

  19. Conformational constraining of inactive and active States of a seven transmembrane receptor by metal ion site engineering in the extracellular end of transmembrane segment V

    DEFF Research Database (Denmark)

    Rosenkilde, Mette M; David, Ralf; Oerlecke, Ilka

    2006-01-01

    The extracellular part of transmembrane segment V (TM-V) is expected to be involved in the activation process of 7TM receptors, but its role is far from clear. Here, we study the highly constitutively active CXC-chemokine receptor encoded by human herpesvirus 8 (ORF74-HHV8), in which a metal ion ...

  20. Perceptions of interactions between staff members calling, and those responding to, rapid response team activations for patient deterioration.

    Science.gov (United States)

    Chalwin, Richard; Flabouris, Arthas; Kapitola, Karoline; Dewick, Leonie

    2016-09-01

    Objectives The aim of the present study was to investigate experiences of staff interactions and non-technical skills (NTS) at rapid response team (RRT) calls, and their association with repeat RRT calls. Methods Mixed-methods surveys were conducted of RRT members and staff who activate the RRT (RRT users) for their perceptions and attitudes regarding the use of NTS during RRT calls. Responses within the survey were recorded as Likert items, ranked data and free comments. The latter were coded into nodes relating to one of four NTS domains: leadership, communication, cooperation and planning. Results Two hundred and ninety-seven (32%) RRT users and 79 (73.8%) RRT members provided responses. Of the RRT user respondents, 76.5% had activated the RRT at some point. Deficits in NTS at RRT calls were revealed, with 36.9% of users not feeling involved during RRT calls and 24.7% of members perceiving that users were disinterested. Unresolved user clinical concerns, or persistence of RRT calling criteria, were reasons cited by 37.6% and 23%, respectively, of RRT users for reactivating an RRT to the same patient. Despite recollections of conflict at previous RRT calls, 92% of users would still reactivate the RRT. The most common theme in the free comments related to deficiencies in cooperation (52.9%), communication (28.6%) and leadership (14.3%). Conclusions This survey of RRT users and members revealed problems with RRT users' and members' interactions at the time of an RRT call. Both users and members considered NTS to be important, but lacking. These findings support NTS training for RRT members and users. What is known about the topic? Previous surveying has related experiences of criticism and conflict between clinical staff at RRT activations. This leads to reluctance to call the RRT when indicated, with risks to patient safety, especially if subsequent RRT activation is necessary. Training in NTS has improved clinician interactions in simulated emergencies, but the

  1. Ligand-induced conformational changes: Improved predictions of ligand binding conformations and affinities

    DEFF Research Database (Denmark)

    Frimurer, T.M.; Peters, Günther H.J.; Iversen, L.F.

    2003-01-01

    A computational docking strategy using multiple conformations of the target protein is discussed and evaluated. A series of low molecular weight, competitive, nonpeptide protein tyrosine phosphatase inhibitors are considered for which the x-ray crystallographic structures in complex with protein...... tyrosine phosphatase 1 B (PTP1B) are known. To obtain a quantitative measure of the impact of conformational changes induced by the inhibitors, these were docked to the active site region of various structures of PTP1B using the docking program FlexX. Firstly, the inhibitors were docked to a PTP1B crystal...... predicted binding energy and a correct docking mode. Thirdly, to improve the predictability of the docking procedure in the general case, where only a single target protein structure is known, we evaluate an approach which takes possible protein side-chain conformational changes into account. Here, side...

  2. Locally conformal symplectic manifolds

    Directory of Open Access Journals (Sweden)

    Izu Vaisman

    1985-01-01

    Full Text Available A locally conformal symplectic (l. c. s. manifold is a pair (M2n,Ω where M2n(n>1 is a connected differentiable manifold, and Ω a nondegenerate 2-form on M such that M=⋃αUα (Uα- open subsets. Ω/Uα=eσαΩα, σα:Uα→ℝ, dΩα=0. Equivalently, dΩ=ω∧Ω for some closed 1-form ω. L. c. s. manifolds can be seen as generalized phase spaces of Hamiltonian dynamical systems since the form of the Hamilton equations is, in fact, preserved by homothetic canonical transformations. The paper discusses first Hamiltonian vector fields, and infinitesimal automorphisms (i. a. on l. c. s. manifolds. If (M,Ω has an i. a. X such that ω(X≠0, we say that M is of the first kind and Ω assumes the particular form Ω=dθ−ω∧θ. Such an M is a 2-contact manifold with the structure forms (ω,θ, and it has a vertical 2-dimensional foliation V. If V is regular, we can give a fibration theorem which shows that M is a T2-principal bundle over a symplectic manifold. Particularly, V is regular for some homogeneous l. c. s, manifolds, and this leads to a general construction of compact homogeneous l. c. s, manifolds. Various related geometric results, including reductivity theorems for Lie algebras of i. a. are also given. Most of the proofs are adaptations of corresponding proofs in symplectic and contact geometry. The paper ends with an Appendix which states an analogous fibration theorem in Riemannian geometry.

  3. A small molecule with anticancer and antimetastatic activities induces rapid mitochondrial-associated necrosis in breast cancer.

    Science.gov (United States)

    Bastian, Anja; Thorpe, Jessica E; Disch, Bryan C; Bailey-Downs, Lora C; Gangjee, Aleem; Devambatla, Ravi K V; Henthorn, Jim; Humphries, Kenneth M; Vadvalkar, Shraddha S; Ihnat, Michael A

    2015-05-01

    Therapy for treatment-resistant breast cancer provides limited options and the response rates are low. Therefore, the development of therapies with alternative chemotherapeutic strategies is necessary. AG311 (5-[(4-methylphenyl)thio]-9H-pyrimido[4,5-b]indole-2,4-diamine), a small molecule, is being investigated in preclinical and mechanistic studies for treatment of resistant breast cancer through necrosis, an alternative cell death mechanism. In vitro, AG311 induces rapid necrosis in numerous cancer cell lines as evidenced by loss of membrane integrity, ATP depletion, HMGB1 (high-mobility group protein B1) translocation, nuclear swelling, and stable membrane blebbing in breast cancer cells. Within minutes, exposure to AG311 also results in mitochondrial depolarization, superoxide production, and increased intracellular calcium levels. Additionally, upregulation of mitochondrial oxidative phosphorylation results in sensitization to AG311. This AG311-induced cell death can be partially prevented by treatment with the mitochondrial calcium uniporter inhibitor, Ru360 [(μ)[(HCO2)(NH3)4Ru]2OCl3], or an antioxidant, lipoic acid. Additionally, AG311 does not increase apoptotic markers such as cleavage of poly (ADP-ribose) polymerase (PARP) or caspase-3 and -7 activity. Importantly, in vivo studies in two orthotopic breast cancer mouse models (xenograft and allograft) demonstrate that AG311 retards tumor growth and reduces lung metastases better than clinically used agents and has no gross or histopathological toxicity. Together, these data suggest that AG311 is a first-in-class antitumor and antimetastatic agent inducing necrosis in breast cancer tumors, likely through the mitochondria. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  4. Interactions between microbial activity and distribution and mineral coatings on sand grains from rapid sand filters treating groundwater

    DEFF Research Database (Denmark)

    Gülay, Arda; Tatari, Karolina; Musovic, Sanin

    Rapid sand filtration is a traditional and widespread technology for drinking water purification which combines biological, chemical and physical processes together. Granular media, especially sand, is a common filter material that allows several oxidized compounds to accumulate on its surface...

  5. Design, synthesis, and structure-activity relationship study of conformationally constrained analogs of indole-3-carboxamides as novel CB1 cannabinoid receptor agonists.

    Science.gov (United States)

    Kiyoi, Takao; York, Mark; Francis, Stuart; Edwards, Darren; Walker, Glenn; Houghton, Andrea K; Cottney, Jean E; Baker, James; Adam, Julia M

    2010-08-15

    Novel tricyclic indole-3-carboxamides were synthesized as structurally restricted analogs of bicyclic indoles, and found to be potent CB1 cannabinoid receptor agonists. The CB1 agonist activity depended on the absolute configuration of the chiral center of the tricyclic ring. The preferred enantiomer was more potent than the structurally unconstrained lead compound. Structure-activity relationships in the amide side chain of the indole C-3 position were also investigated. 2010 Elsevier Ltd. All rights reserved.

  6. Music Training Enhances Rapid Neural Plasticity of N1 and P2 Source Activation for Unattended Sounds

    OpenAIRE

    Seppänen, Miia; Hämäläinen, Jarmo; Pesonen, Anu-Katriina; Tervaniemi, Mari

    2012-01-01

    Neurocognitive studies have demonstrated that long-term music training enhances the processing of unattended sounds. It is not clear, however, whether music training also modulates rapid (within tens of minutes) neural plasticity for sound encoding. To study this phenomenon, we examined whether adult musicians display enhanced rapid neural plasticity compared to non-musicians. More specifically, we compared the modulation of P1, N1, and P2 responses to standard sounds between four unattended ...

  7. Immediate-Early Gene Transcriptional Activation in Hippocampus Ca1 and Ca3 Does Not Accurately Reflect Rapid, Pattern Completion-Based Retrieval of Context Memory

    Science.gov (United States)

    Pevzner, Aleksandr; Guzowski, John F.

    2015-01-01

    No studies to date have examined whether immediate-early gene (IEG) activation is driven by context memory recall. To address this question, we utilized the context preexposure facilitation effect (CPFE) paradigm. In CPFE, animals acquire contextual fear conditioning through hippocampus-dependent rapid retrieval of a previously formed contextual…

  8. Rapid Screening of Active Components with an Osteoclastic Inhibitory Effect in Herba epimedii Using Quantitative Pattern–Activity Relationships Based on Joint-Action Models

    Directory of Open Access Journals (Sweden)

    Xiao-Yan Yuan

    2017-10-01

    Full Text Available Screening of bioactive components is important for modernization and quality control of herbal medicines, while the traditional bioassay-guided phytochemical approach is time-consuming and laborious. The presented study proposes a strategy for rapid screening of active components from herbal medicines. As a case study, the quantitative pattern–activity relationship (QPAR between compounds and the osteoclastic inhibitory effect of Herba epimedii, a widely used herbal medicine in China, were investigated based on joint models. For model construction, standard mixtures data showed that the joint-action models are better than the partial least-squares (PLS model. Then, the Good2bad value, which could reflect components’ importance based on Monte Carlo sampling, was coupled with the joint-action models for screening of active components. A compound (baohuoside I and a component composed of compounds with retention times in the 6.9–7.9 min range were selected by our method. Their inhibition rates were higher than icariin, the key bioactive compound in Herba epimedii, which could inhibit osteoclast differentiation and bone resorption in a previous study. Meanwhile, the half-maximal effective concentration, namely, EC50 value of the selected component was 7.54 μg/mL, much smaller than that of baohuoside I—77 μg/mL—which indicated that there is synergistic action between compounds in the selected component. The results clearly show our proposed method is simple and effective in screening the most-bioactive components and compounds, as well as drug-lead components, from herbal medicines.

  9. Assessment of early thromboelastometric variables from extrinsically activated assays with and without aprotinin for rapid detection of fibrinolysis.

    Science.gov (United States)

    Dirkmann, Daniel; Görlinger, Klaus; Peters, Jürgen

    2014-09-01

    Although thromboelastometry (ROTEM®) and thrombelastography can be used for bedside diagnosis of fibrinolysis, the time needed for detection is often prolonged. Since untreated fibrinolysis can result in consumption of coagulation factors and bleeding, early diagnosis and decision making are desirable. Accordingly, we assessed ROTEM variables from extrinsically activated assays with (APTEM) and without (EXTEM) addition of aprotinin for their ability to rapidly identify fibrinolysis. Specifically, we tested the hypotheses that prolonged clotting time, clot formation time, low clot firmness (at 5, 10, 15, and 20 minutes, designated A5, A10, A15, and A20, respectively), low maximum clot firmness (MCF) in EXTEM assays, and differences in these variables from parallel APTEM and EXTEM assays (designated as Δvariables) predict fibrinolysis. Data from 411 thromboelastometric measurements (obtained from 352 patients) with fibrinolysis and from 2537 measurements without fibrinolysis (obtained from 1605 patients) were assessed and analyzed using receiver operating characteristics. Data were analyzed as a pooled fibrinolysis cohort, and subanalyses were performed from sets assigned to categories of fibrinolysis related to the timing of thrombus lysis (i.e., a decrease of clot firmness to fibrinolysis. AUCs were compared to identify the variable providing the best predictive association with fibrinolysis. As a secondary end point, optimum cutoff values at the point estimate corresponding to the greatest Youden index were calculated along with the respective sensitivities and specificities. In the pooled cohort, clot formation time (AUC: 0.652 [0.016]), α-angle (AUC: 0.675 [0.015]), A5 (AUC: 0.718 [0.013]), A10 (AUC: 0.734 [0.0.13]), A15 (AUC: 0.752 [0.013]), A20 (AUC: 0.771 [0.013]), and MCF (AUC: 0.799 [0.012]) predicted fibrinolysis. Fibrinolysis was also predicted by ΔA15 (AUC: 0.675 [0.016]), ΔA20 (AUC: 0.719 [0.015]), and ΔMCF (AUC: 0.812 [0.013]). AUCs increased in

  10. The C-terminal residue of phage Vp16 PDF, the smallest peptide deformylase, acts as an offset element locking the active conformation.

    Science.gov (United States)

    Grzela, Renata; Nusbaum, Julien; Fieulaine, Sonia; Lavecchia, Francesco; Bienvenut, Willy V; Dian, Cyril; Meinnel, Thierry; Giglione, Carmela

    2017-09-08

    Prokaryotic proteins must be deformylated before the removal of their first methionine. Peptide deformylase (PDF) is indispensable and guarantees this mechanism. Recent metagenomics studies revealed new idiosyncratic PDF forms as the most abundant family of viral sequences. Little is known regarding these viral PDFs, including the capacity of the corresponding encoded proteins to ensure deformylase activity. We provide here the first evidence that viral PDFs, including the shortest PDF identified to date, Vp16 PDF, display deformylase activity in vivo, despite the absence of the key ribosome-interacting C-terminal region. Moreover, characterization of phage Vp16 PDF underscores unexpected structural and molecular features with the C-terminal Isoleucine residue significantly contributing to deformylase activity both in vitro and in vivo. This residue fully compensates for the absence of the usual long C-domain. Taken together, these data elucidate an unexpected mechanism of enzyme natural evolution and adaptation within viral sequences.

  11. Ligand induced conformational change in Lys{sup 49}-phospholipase A{sub 2} hints at a molecular mechanism for membrane damaging activity

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosio, A.L.B.; Souza, D.H.F. de; Garratt, R.C. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil); Nonato, M.C.; Ward, R.J. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil); Selistre de Araujo, H.S. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil); Arni, R. [Universidade Estadual Paulista (UNESP), Sao Jose do Rio Preto, SP (Brazil); Ownby, C.L. [Oklahoma State Univ., OK (United States)

    2004-07-01

    An activation mechanism for Lys{sup 49}-phospholipase A{sub 2} is proposed based on structural evidence gathered from 3 different crystal forms of the ACL myotoxin, together with other available structures from the same subclass of enzymes. This provides for the first time, a direct structural connection between the phospholipase 'active site' and the C-terminal 'myotoxic site', justifying the otherwise enigmatic conservation of the residues of the former in supposedly catalytically inactive molecules. (author)

  12. Some Progress in Conformal Geometry

    Directory of Open Access Journals (Sweden)

    Sun-Yung A. Chang

    2007-12-01

    Full Text Available This is a survey paper of our current research on the theory of partial differential equations in conformal geometry. Our intention is to describe some of our current works in a rather brief and expository fashion. We are not giving a comprehensive survey on the subject and references cited here are not intended to be complete. We introduce a bubble tree structure to study the degeneration of a class of Yamabe metrics on Bach flat manifolds satisfying some global conformal bounds on compact manifolds of dimension 4. As applications, we establish a gap theorem, a finiteness theorem for diffeomorphism type for this class, and diameter bound of the $sigma_2$-metrics in a class of conformal 4-manifolds. For conformally compact Einstein metrics we introduce an eigenfunction compactification. As a consequence we obtain some topological constraints in terms of renormalized volumes.

  13. Steady states in conformal theories

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    A novel conjecture regarding the steady state behavior of conformal field theories placed between two heat baths will be presented. Some verification of the conjecture will be provided in the context of fluid dynamics and holography.

  14. Conformity Adequacy Review: Region 5

    Science.gov (United States)

    Resources are for air quality and transportation government and community leaders. Information on the conformity SIP adequacy/inadequacy of state implementation plans (SIPs) in EPA Region 5 (IL, IN, MI, OH, WI) is provided here.

  15. STRUCTURE OF THE COMPLEX BETWEEN TRYPANOSOMAL TRIOSEPHOSPHATE ISOMERASE AND N-HYDROXY-4-PHOSPHONO-BUTANAMIDE - BINDING AT THE ACTIVE-SITE DESPITE AN OPEN FLEXIBLE LOOP CONFORMATION

    NARCIS (Netherlands)

    VERLINDE, CLMJ; WITMANS, CJ; PIJNING, T; KALK, KH; HOL, WGJ; CALLENS, M; OPPERDOES, FR

    1992-01-01

    The structure of triosephosphate isomerase from Trypanosoma brucei complexed with the competitive inhibitor N-hydroxy-4-phosphono-butanamide was determined by X-ray crystallography to a resolution of 2.84 angstrom. Full occupancy binding of the inhibitor is observed only at one of the active sites

  16. Adaptive mutations in the nuclear export protein of human-derived H5N1 strains facilitate a polymerase activity-enhancing conformation

    NARCIS (Netherlands)

    P. Reuther (Peter); S. Giese (Sebastian); H.M. Götz (Hannelore); N. Kilb (Normann); B. Mänz (Benjamin); L. Brunotte (Linda); M. Schwemmle (Martin)

    2014-01-01

    textabstractThe nuclear export protein (NEP) (NS2) of the highly pathogenic human-derived H5N1 strain A/Thailand/1(KAN-1)/2004 with the adaptive mutation M16I greatly enhances the polymerase activity in human cells in a concentration-dependent manner. While low NEP levels enhance the polymerase

  17. Falsification of Mannheim's conformal gravity

    CERN Document Server

    Yoon, Youngsub

    2013-01-01

    We show that Mannheim's conformal gravity, whose potential has a term proportional to $1/r$ and another term proportional to $r$, doesn't reduce to Newtonian gravity at short distances. Therefore, despite the claim that it successfully explains galaxy rotation curves, it seems falsified by numerous Cavendish-type experiments performed at laboratories on Earth whose work haven't found any deviations from Newton's theory. Moreover, when Mannheim used his potential to fit the galaxy rotation curve, he used the Newtonian formula to calculate the effects of the term proportional to $1/r$, not the conformal gravity one. So, he lacked consistency. After all, he would not have been able to use the conformal gravity one either since it deviates so much from the Newtonian one, which the conformal gravity one should reduce to. We also give a couple of other similar reasons why Mannheim's conformal gravity is wrong. For example, the gravitational potential of conformal gravity doesn't reduce to the Newtonian one even in ...

  18. The conformational musings of a medicinal chemist.

    Science.gov (United States)

    Finch, Harry

    2014-03-01

    Structure-based drug design strategies based on X-ray crystallographic data of ligands bound to biological targets or computationally derived pharmacophore models have been introduced over the past 25 years or so. These have now matured and are deeply embedded in the drug discovery process in most pharmaceutical and biotechnology companies where they continue to play a major part in the discovery of new medicines and drug candidates. Newly developed NMR methods can now provide a full description of the conformations in which ligands exist in free solution, crucially allowing those that are dominant to be identified. Integrating experimentally determined conformational information on active and inactive molecules in drug discovery programmes, alongside the existing techniques, should have a major impact on the success of drug discovery. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. In silico Exploration of the Conformational Universe of GPCRs.

    Science.gov (United States)

    Rodríguez-Espigares, Ismael; Kaczor, Agnieszka A; Selent, Jana

    2016-07-01

    The structural plasticity of G protein coupled receptors (GPCRs) leads to a conformational universe going from inactive to active receptor states with several intermediate states. Many of them have not been captured yet and their role for GPCR activation is not well understood. The study of this conformational space and the transition dynamics between different receptor populations is a major challenge in molecular biophysics. The rational design of effector molecules that target such receptor populations allows fine-tuning receptor signalling with higher specificity to produce drugs with safer therapeutic profiles. In this minireview, we outline highly conserved receptor regions which are considered determinant for the establishment of distinct receptor states. We then discuss in-silico approaches such as dimensionality reduction methods and Markov State Models to explore the GPCR conformational universe and exploit the obtained conformations through structure-based drug design. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. An engineered second disulfide bond restricts lymphotactin/XCL1 to a chemokine-like conformation with XCR1 agonist activity.

    Science.gov (United States)

    Tuinstra, Robbyn L; Peterson, Francis C; Elgin, E Sonay; Pelzek, Adam J; Volkman, Brian F

    2007-03-13

    Chemokines adopt a conserved tertiary structure stabilized by two disulfide bridges and direct the migration of leukocytes. Lymphotactin (Ltn) is a unique chemokine in that it contains only one disulfide and exhibits large-scale structural heterogeneity. Under physiological solution conditions (37 degrees C and 150 mM NaCl), Ltn is in equilibrium between the canonical chemokine fold (Ltn10) and a distinct four-stranded beta-sheet (Ltn40). Consequently, it has not been possible to address the biological significance of each structural species independently. To stabilize the Ltn10 structure in a manner independent of specific solution conditions, Ltn variants containing a second disulfide bridge were designed. Placement of the new cysteines was based on a sequence alignment of Ltn with either the first (Ltn-CC1) or third disulfide (Ltn-CC3) in the CC chemokine, HCC-2. NMR data demonstrate that both CC1 and CC3 retain the Ltn10 chemokine structure and no longer exhibit structural rearrangement. The ability of each mutant to activate the Ltn receptor, XCR1, has been tested using an intracellular Ca2+ flux assay. These data support the conclusion that the chemokine fold of Ltn10 is responsible for receptor activation. We also examined the role of amino- and carboxyl-terminal residues in Ltn-mediated receptor activation. In contrast to previous reports, we find that the 25 residues comprising the novel C-terminal extension do not participate in receptor activation, while the native N-terminus is absolutely required for Ltn function.

  1. Active and energy-dependent rapid formation of cell aggregates in the thermophilic photosynthetic bacterium Chloroflexus aggregans.

    Science.gov (United States)

    Hanada, Satoshi; Shimada, Keizo; Matsuura, Katsumi

    2002-03-05

    The thermophilic filamentous phototroph Chloroflexus aggregans was able to form a bacterial mat-like dense cell aggregate rapidly. The aggregate formation, which was observed in growing cells in a liquid medium in a bottle, occurred every time within 20-30 min after the cells were dispersed by shaking. The aggregation depended on the energy supplied by photosynthesis or respiration. Cells aggregated most rapidly under temperature and pH conditions that support maximum growth. The aggregation was also accelerated by the addition of 3-isobutyl-1-methylxanthine that inhibits cyclic 3',5'-AMP phosphodiesterase. Microscopic observation revealed that the bacterium has a fast gliding mobility (1-3 microm s(-1)). The distinctive cell aggregation of C. aggregans was due to this rapid gliding movement.

  2. Biology of three Malacostraca (Decapoda) in a Mediterranean lagoon with particular emphasis on the effect of rapid environmental changes on the activity (catchability) of the species

    Science.gov (United States)

    Crivelli, A. J.

    1982-12-01

    The activity of three Malacostraca (Decapoda), Crangon crangon, Carcinus aestuarii and Paleamon squilla, was studied following rapid environmental changes in a Mediterranean lagoon linked temporarily with the sea. Nekton was sampled every 2-3 days using fixed fyke nets. A canonical analysis and a stepwise multiple regression were computed to determine which factor(s) can predict or account for the catch of these three decapods. In spite of rapid environmental changes no exceptional mortality was observed in each of the three species. Temperature is the environmental factor with major impact on the activity of C. crangon. Activity of P. squilla is controlled by water depth. At a depth of less than 20 cm two factors, salinity and phase of the moon, have a significant influence on the activity of this species. At depths deeper than 20 cm the activity is inhibited. There is only a weak relationship between the catch of C. aestuarii and salinity. Additional data on the life cycle of these species are given. The limitations of a monthly sampling period are discussed and the need for more short-term, consecutive sampling periods is stressed in order to understand the dynamics of systems with rapid environmental fluctuations.

  3. CONFORMANCE IMPROVEMENT USING GELS

    Energy Technology Data Exchange (ETDEWEB)

    Randall S. Seright

    2003-09-01

    This report describes work performed during the second year of the project, ''Conformance Improvement Using Gels.'' The project has two objectives. The first objective is to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective is to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil. Pore-level images from X-ray computed microtomography were re-examined for Berea sandstone and porous polyethylene. This analysis suggests that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than a gel-ripping mechanism. This finding helps to explain why aqueous gels can reduce permeability to water more than to oil. We analyzed a Cr(III)-acetate-HPAM gel treatment in a production well in the Arbuckle formation. The availability of accurate pressure data before, during, and after the treatment was critical for the analysis. After the gel treatment, water productivity was fairly constant at about 20% of the pre-treatment value. However, oil productivity was stimulated by a factor of 18 immediately after the treatment. During the six months after the treatment, oil productivity gradually decreased to approach the pre-treatment value. To explain this behavior, we proposed that the fracture area open to oil flow was increased substantially by the gel treatment, followed by a gradual closing of the fractures during subsequent production. For a conventional Cr(III)-acetate-HPAM gel, the delay between gelant preparation and injection into a fracture impacts the placement, leakoff, and permeability reduction behavior. Formulations placed as partially formed gels showed relatively low pressure gradients during placement, and yet substantially reduced the

  4. CONFORMANCE IMPROVEMENT USING GELS

    Energy Technology Data Exchange (ETDEWEB)

    Randall S. Seright

    2004-09-30

    This report describes work performed during the third and final year of the project, ''Conformance Improvement Using Gels.'' Corefloods revealed throughput dependencies of permeability reduction by polymers and gels that were much more prolonged during oil flow than water flow. This behavior was explained using simple mobility ratio arguments. A model was developed that quantitatively fits the results and predicts ''clean up'' times for oil productivity when production wells are returned to service after application of a polymer or gel treatment. X-ray computed microtomography studies of gels in strongly water-wet Berea sandstone and strongly oil-wet porous polyethylene suggested that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than gel-ripping or gel-displacement mechanisms. In contrast, analysis of data from the University of Kansas suggests that the gel-ripping or displacement mechanisms are more important in more permeable, strongly water-wet sandpacks. These findings help to explain why aqueous gels can reduce permeability to water more than to oil under different conditions. Since cement is the most commonly used material for water shutoff, we considered when gels are preferred over cements. Our analysis and experimental results indicated that cement cannot be expected to completely fill (top to bottom) a vertical fracture of any width, except near the wellbore. For vertical fractures with apertures less than 4 mm, the cement slurry will simply not penetrate very far into the fracture. For vertical fractures with apertures greater than 4 mm, the slurry may penetrate a substantial distance into the bottom part of the fracture. However, except near the wellbore, the upper part of the fracture will remain open due to gravity segregation. We compared various approaches to plugging fractures using gels, including (1) varying polymer content, (2) varying placement (extrusion) rate

  5. To conform or not to conform: spontaneous conformity diminishes the sensitivity to monetary outcomes.

    Science.gov (United States)

    Yu, Rongjun; Sun, Sai

    2013-01-01

    When people have different opinions in a group, they often adjust their own attitudes and behaviors to match the group opinion, known as social conformity. The affiliation account of normative conformity states that people conform to norms in order to 'fit in', whereas the accuracy account of informative conformity posits that the motive to learn from others produces herding. Here, we test another possibility that following the crowd reduces the experienced negative emotion when the group decision turns out to be a bad one. Using event related potential (ERP) combined with a novel group gambling task, we found that participants were more likely to choose the option that was predominately chosen by other players in previous trials, although there was little explicit normative pressure at the decision stage and group choices were not informative. When individuals' choices were different from others, the feedback related negativity (FRN), an ERP component sensitive to losses and errors, was enhanced, suggesting that being independent is aversive. At the outcome stage, the losses minus wins FRN effect was significantly reduced following conformity choices than following independent choices. Analyses of the P300 revealed similar patterns both in the response and outcome period. Our study suggests that social conformity serves as an emotional buffer that protects individuals from experiencing strong negative emotion when the outcomes are bad.

  6. To conform or not to conform: spontaneous conformity diminishes the sensitivity to monetary outcomes.

    Directory of Open Access Journals (Sweden)

    Rongjun Yu

    Full Text Available When people have different opinions in a group, they often adjust their own attitudes and behaviors to match the group opinion, known as social conformity. The affiliation account of normative conformity states that people conform to norms in order to 'fit in', whereas the accuracy account of informative conformity posits that the motive to learn from others produces herding. Here, we test another possibility that following the crowd reduces the experienced negative emotion when the group decision turns out to be a bad one. Using event related potential (ERP combined with a novel group gambling task, we found that participants were more likely to choose the option that was predominately chosen by other players in previous trials, although there was little explicit normative pressure at the decision stage and group choices were not informative. When individuals' choices were different from others, the feedback related negativity (FRN, an ERP component sensitive to losses and errors, was enhanced, suggesting that being independent is aversive. At the outcome stage, the losses minus wins FRN effect was significantly reduced following conformity choices than following independent choices. Analyses of the P300 revealed similar patterns both in the response and outcome period. Our study suggests that social conformity serves as an emotional buffer that protects individuals from experiencing strong negative emotion when the outcomes are bad.

  7. Conformational changes associated with the binding of zinc acetate at the putative active site of XcTcmJ, a cupin from Xanthomonas campestris pv. campestris.

    Science.gov (United States)

    Axelrod, Herbert L; Kozbial, Piotr; McMullan, Daniel; Krishna, S Sri; Miller, Mitchell D; Abdubek, Polat; Acosta, Claire; Astakhova, Tamara; Carlton, Dennis; Caruthers, Jonathan; Chiu, Hsiu Ju; Clayton, Thomas; Deller, Marc C; Duan, Lian; Elias, Ylva; Feuerhelm, Julie; Grzechnik, Slawomir K; Grant, Joanna C; Han, Gye Won; Jaroszewski, Lukasz; Jin, Kevin K; Klock, Heath E; Knuth, Mark W; Kumar, Abhinav; Marciano, David; Morse, Andrew T; Murphy, Kevin D; Nigoghossian, Edward; Okach, Linda; Oommachen, Silvya; Paulsen, Jessica; Reyes, Ron; Rife, Christopher L; Tien, Henry J; Trout, Christina V; van den Bedem, Henry; Weekes, Dana; White, Aprilfawn; Xu, Qingping; Zubieta, Chloe; Hodgson, Keith O; Wooley, John; Elsliger, Marc André; Deacon, Ashley M; Godzik, Adam; Lesley, Scott A; Wilson, Ian A

    2010-10-01

    In the plant pathogen Xanthomonas campestris pv. campestris, the product of the tcmJ gene, XcTcmJ, encodes a protein belonging to the RmlC family of cupins. XcTcmJ was crystallized in a monoclinic space group (C2) in the presence of zinc acetate and the structure was determined to 1.6 Å resolution. Previously, the apo structure has been reported in the absence of any bound metal ion [Chin et al. (2006), Proteins, 65, 1046-1050]. The most significant difference between the apo structure and the structure of XcTcmJ described here is a reorganization of the binding site for zinc acetate, which was most likely acquired from the crystallization solution. This site is located in the conserved metal ion-binding domain at the putative active site of XcTcmJ. In addition, an acetate was also bound within coordination distance of the zinc. In order to accommodate this binding, rearrangement of a conserved histidine ligand is required as well as several nearby residues within and around the putative active site. These observations indicate that binding of zinc serves a functional role in this cupin protein.

  8. What Automaticity Deficit? Activation of Lexical Information by Readers with Dyslexia in a Rapid Automatized Naming Stroop-Switch Task

    Science.gov (United States)

    Jones, Manon W.; Snowling, Margaret J.; Moll, Kristina

    2016-01-01

    Reading fluency is often predicted by rapid automatized naming (RAN) speed, which as the name implies, measures the automaticity with which familiar stimuli (e.g., letters) can be retrieved and named. Readers with dyslexia are considered to have less "automatized" access to lexical information, reflected in longer RAN times compared with…

  9. Conformal Window and Correlation Functions in Lattice Conformal QCD

    CERN Document Server

    Iwasaki, Y

    2012-01-01

    We discuss various aspects of Conformal Field Theories on the Lattice. We investigate the SU(3) gauge theory with Nf fermions in the fundamental representation. First we make a brief review of our previous works on the phase structure of lattice gauge theories in terms of the gauge coupling constant and the quark mass. We thereby clarify the reason why we conjecture that the conformal window is 7 = 1 exhibit the characteristics of the conformal function with IR cutoff, an exponential damping with power correction. Investigating our numerical data by a new method, the "micro-analysis" of propagators, we observe that our data are consistent with the picture that the Nf=7 case and the Nf=2 at T ~ 2Tc case are close to the meson unparticle model. On the other hand, the Nf=16 case and the Nf=2 at T= 10^2 ~10^5 Tc cases are close to the fermion unparticle model.

  10. Influence of polyols on the stability and kinetic parameters of invertase from Candida utilis: correlation with the conformational stability and activity.

    Science.gov (United States)

    Gangadhara; Ramesh Kumar, Parigi; Prakash, Vishweshwaraiah

    2008-12-01

    Invertase (beta-D -fructofuranoside fructohydrolase-E.C. 3.2.1.26) is a sucrose hydrolyzing enzyme found in microbial, plant and animal sources. Invertase from Candida utilis is a dimeric glycoprotein composed of two identical monomer subunits with an apparent molecular mass of 150 kDa. We investigated the mechanism of stabilization of invertase with polyols (glycerol, xylitol, and sorbitol). Activity, thermodynamic and kinetic measurements of invertase were performed as a function of polyol concentration and showed that polyols act as very effective stabilizing agents. The result from the solvent-invertase interaction shows preferential exclusion of the polyols from the protein domain leading to preferential hydration of protein. Apparent thermal denaturation temperature of the protein (T ( m )) rose from 75 degrees C to a maximum of 85 degrees C in 30% glycerol. The stabilization has been attributed to the preferential hydration of the enzyme.

  11. Increased extracellular collagen matrix in myocardial sleeves of pulmonary veins: an additional mechanism facilitating repetitive rapid activities in chronic pacing-induced sustained atrial fibrillation.

    Science.gov (United States)

    Chiu, Yung-Tsung; Wu, Tsu-Juey; Wei, Hao-Ji; Cheng, Ching-Chang; Lin, Nai-Nu; Chen, Ying-Tsung; Ting, Chih-Tai

    2005-07-01

    Increased ECM in canine PVs. Cell uncoupling due to fibrosis or increased extracellular collagen matrix (ECM) affects the formation of ectopic focal activity. Whether or not the increase of ECM also exists in the pulmonary veins (PVs) with rapid atrial pacing is unknown. We sought to test the hypothesis that in chronic atrial pacing dogs with sustained atrial fibrillation (AF), the amount of ECM was increased in both atria and the PVs. We induced sustained AF in dogs by rapid atrial pacing. Computerized mapping techniques were used to map both atria and the PVs. We also used histological assessment to quantify the amount of ECM. After 118+/-24 days of rapid atrial pacing, sustained AF was induced in 7 dogs. Repetitive rapid activities (RRAs) either continuously or intermittently arose from the PVs during sustained AF. Histological study shows that there was no fibrosis in both atrial free walls and the PVs. However, the amount of ECM was increased in these regions. The mean ECM surface area fraction at each region in the dogs with sustained AF was all significantly higher compared to the corresponding region in normal dogs. Similarly, the heterogeneity of the ECM surface area fraction at each region in the dogs with sustained AF was also all significantly higher compared to normal dogs. In chronic atrial pacing-induced sustained AF, structural remodeling (i.e., inhomogeneous increase of ECM) also involves the PVs. Reduced coupling of the myocytes in the PV due to histological changes may provide an additional mechanism facilitating RRAs.

  12. The C-terminal random coil region tunes the Ca²⁺-binding affinity of S100A4 through conformational activation.

    Directory of Open Access Journals (Sweden)

    Annette Duelli

    Full Text Available S100A4 interacts with many binding partners upon Ca2+ activation and is strongly associated with increased metastasis formation. In order to understand the role of the C-terminal random coil for the protein function we examined how small angle X-ray scattering of the wild-type S100A4 and its C-terminal deletion mutant (residues 1-88, Δ13 changes upon Ca2+ binding. We found that the scattering intensity of wild-type S100A4 changes substantially in the 0.15-0.25 Å-1 q-range whereas a similar change is not visible in the C-terminus deleted mutant. Ensemble optimization SAXS modeling indicates that the entire C-terminus is extended when Ca2+ is bound. Pulsed field gradient NMR measurements provide further support as the hydrodynamic radius in the wild-type protein increases upon Ca2+ binding while the radius of Δ13 mutant does not change. Molecular dynamics simulations provide a rational explanation of the structural transition: the positively charged C-terminal residues associate with the negatively charged residues of the Ca2+-free EF-hands and these interactions loosen up considerably upon Ca2+-binding. As a consequence the Δ13 mutant has increased Ca2+ affinity and is constantly loaded at Ca2+ concentration ranges typically present in cells. The activation of the entire C-terminal random coil may play a role in mediating interaction with selected partner proteins of S100A4.

  13. 40 CFR 93.154 - Conformity analysis.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Conformity analysis. 93.154 Section 93...) DETERMINING CONFORMITY OF FEDERAL ACTIONS TO STATE OR FEDERAL IMPLEMENTATION PLANS Determining Conformity of General Federal Actions to State or Federal Implementation Plans § 93.154 Conformity analysis. Any Federal...

  14. Conformational properties of polymers

    Indian Academy of Sciences (India)

    activity in experiments involving the manipulation of a single biomolecules. This interest has been fueled by the desire to understand the fundamental mechanisms at play in the transcription and replication processes in DNA, elastic, structural and functional properties of proteins and DNA/RNA etc. [4–9]. This became pos-.

  15. Compact conformations of human protein disulfide isomerase.

    Directory of Open Access Journals (Sweden)

    Shang Yang

    Full Text Available Protein disulfide isomerase (PDI composed of four thioredoxin-like domains a, b, b', and a', is a key enzyme catalyzing oxidative protein folding in the endoplasmic reticulum. Large scale molecular dynamics simulations starting from the crystal structures of human PDI (hPDI in the oxidized and reduced states were performed. The results indicate that hPDI adopts more compact conformations in solution than in the crystal structures, which are stabilized primarily by inter-domain interactions, including the salt bridges between domains a and b' observed for the first time. A prominent feature of the compact conformations is that the two catalytic domains a and a' can locate close enough for intra-molecular electron transfer, which was confirmed by the characterization of an intermediate with a disulfide between the two domains. Mutations, which disrupt the inter-domain interactions, lead to decreased reductase activity of hPDI. Our molecular dynamics simulations and biochemical experiments reveal the intrinsic conformational dynamics of hPDI and its biological impact.

  16. Salmon calcitonin: conformational changes and stabilizer effects

    Directory of Open Access Journals (Sweden)

    Shan-Yang Lin

    2015-11-01

    Full Text Available The therapeutic activity of peptides or protein drugs is highly dependent on their conformational structure. The protein structure is flexible and responds to external conditions, which may compromise the protein's native conformation and influence its physical and chemical stability. The physical and chemical stability of peptides or protein drugs are important characteristics of biopharmaceutical products. Calcitonin (CT is a polypeptide hormone that participates in diverse physiological functions in humans; therefore, it is a potentially useful protein for investigations of different aspects of pharmacology and drug delivery systems. Of the different types of CT available for clinical use, salmon CT (sCT is one of the most potent. In this review article, the commercially available sCT was selected as a suitable peptide candidate for the discussion of its stability and conformational changes in the aqueous and solid states using Fourier transform infrared (FTIR spectroscopic analysis under different external conditions, including pH, temperature, drying method, and added excipients. Particularly, excipients that have been optimized as stabilizers of sCT in aqueous solution and as lyophilized and spray-dried drug formulations are also discussed.

  17. CED: a conformational epitope database

    Directory of Open Access Journals (Sweden)

    Huang Jian

    2006-04-01

    Full Text Available Abstract Background Antigen epitopes provide valuable information useful for disease prevention, diagnosis, and treatment. Recently, more and more databases focusing on different types of epitopes have become available. Conformational epitopes are an important form of epitope formed by residues that are sequentially discontinuous but close together in three-dimensional space. These epitopes have implicit structural information, making them attractive for both theoretical and applied biomedical research. However, most existing databases focus on linear rather than conformational epitopes. Description We describe CED, a special database of well defined conformational epitopes. CED provides a collection of conformational epitopes and related information including the residue make up and location of the epitope, the immunological property of the epitope, the source antigen and corresponding antibody of the epitope. All entries in this database are manually curated from articles published in peer review journals. The database can be browsed or searched through a user-friendly web interface. Most epitopes in CED can also be viewed interactively in the context of their 3D structures. In addition, the entries are also hyperlinked to various databases such as Swiss-Prot, PDB, KEGG and PubMed, providing wide background information. Conclusion A conformational epitope database called CED has been developed as an information resource for investigators involved in both theoretical and applied immunology research. It complements other existing specialised epitope databases. The database is freely available at http://web.kuicr.kyoto-u.ac.jp/~ced

  18. QCD-instantons and conformal inversion symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Klammer, D.

    2006-07-15

    Instantons are an essential and non-perturbative part of Quantum Chromodynamics, the theory of strong interactions. One of the most relevant quantities in the instanton calculus is the instanton-size distribution, which can be described on the one hand within the framework of instanton perturbation theory and on the other hand investigated numerically by means of lattice computations. A rapid onset of a drastic discrepancy between these respective results indicates that the underlying physics is not yet well understood. In this work we investigate the appealing possibility of a symmetry under conformal inversion of space-time leading to this deviation. The motivation being that the lattice data seem to be invariant under an inversion of the instanton size. Since the instanton solution of a given size turns into an anti-instanton solution having an inverted size under conformal inversion of space-time, we ask in a first investigation, whether this property is transferred to the quantum level. In order to introduce a new scale, which is indicated by the lattice data and corresponds to the average instanton size as inversion radius, we project the instanton calculus onto the four-dimensional surface of a five-dimensional sphere via stereographic projection. The radius of this sphere is associated with the average instanton size. The result for the instanton size-distribution projected onto the sphere agrees surprisingly well with the lattice data at qualitative level. The resulting symmetry under an inversion of the instanton size is almost perfect. (orig.)

  19. Conformal geometry and quasiregular mappings

    CERN Document Server

    Vuorinen, Matti

    1988-01-01

    This book is an introduction to the theory of spatial quasiregular mappings intended for the uninitiated reader. At the same time the book also addresses specialists in classical analysis and, in particular, geometric function theory. The text leads the reader to the frontier of current research and covers some most recent developments in the subject, previously scatterd through the literature. A major role in this monograph is played by certain conformal invariants which are solutions of extremal problems related to extremal lengths of curve families. These invariants are then applied to prove sharp distortion theorems for quasiregular mappings. One of these extremal problems of conformal geometry generalizes a classical two-dimensional problem of O. Teichmüller. The novel feature of the exposition is the way in which conformal invariants are applied and the sharp results obtained should be of considerable interest even in the two-dimensional particular case. This book combines the features of a textbook an...

  20. Stimulus and Response-Locked P3 Activity in a Dynamic Rapid Serial Visual Presentation (RSVP) Task

    Science.gov (United States)

    2013-01-01

    electroencephalogram EOG electrooculography ERP event - related potential P3 P300 RSVP rapid serial visual presentation RT reaction time NO. OF NO. OF...4 Figure 3. Left: stimulus-locked P3 event - related potentials at electrode Pz from nontargets and targets in each quartile. Right...average). .....6 Figure 5. Left: response-locked P3 event - related potentials at electrode Pz from targets in each quartile. Right: corresponding

  1. Glucose Evokes Rapid Ca2+ and Cyclic AMP Signals by Activating the Cell-Surface Glucose-Sensing Receptor in Pancreatic β-Cells

    Science.gov (United States)

    Nakagawa, Yuko; Nagasawa, Masahiro; Medina, Johan; Kojima, Itaru

    2015-01-01

    Glucose is a primary stimulator of insulin secretion in pancreatic β-cells. High concentration of glucose has been thought to exert its action solely through its metabolism. In this regard, we have recently reported that glucose also activates a cell-surface glucose-sensing receptor and facilitates its own metabolism. In the present study, we investigated whether glucose activates the glucose-sensing receptor and elicits receptor-mediated rapid actions. In MIN6 cells and isolated mouse β-cells, glucose induced triphasic changes in cytoplasmic Ca2+ concentration ([Ca2+]c); glucose evoked an immediate elevation of [Ca2+]c, which was followed by a decrease in [Ca2+]c, and after a certain lag period it induced large oscillatory elevations of [Ca2+]c. Initial rapid peak and subsequent reduction of [Ca2+]c were independent of glucose metabolism and reproduced by a nonmetabolizable glucose analogue. These signals were also blocked by an inhibitor of T1R3, a subunit of the glucose-sensing receptor, and by deletion of the T1R3 gene. Besides Ca2+, glucose also induced an immediate and sustained elevation of intracellular cAMP ([cAMP]c). The elevation of [cAMP]c was blocked by transduction of the dominant-negative Gs, and deletion of the T1R3 gene. These results indicate that glucose induces rapid changes in [Ca2+]c and [cAMP]c by activating the cell-surface glucose-sensing receptor. Hence, glucose generates rapid intracellular signals by activating the cell-surface receptor. PMID:26630567

  2. A key agonist-induced conformational change in the cannabinoid receptor CB1 is blocked by the allosteric ligand Org 27569.

    Science.gov (United States)

    Fay, Jonathan F; Farrens, David L

    2012-09-28

    Allosteric ligands that modulate how G protein-coupled receptors respond to traditional orthosteric drugs are an exciting and rapidly expanding field of pharmacology. An allosteric ligand for the cannabinoid receptor CB1, Org 27569, exhibits an intriguing effect; it increases agonist binding, yet blocks agonist-induced CB1 signaling. Here we explored the mechanism behind this behavior, using a site-directed fluorescence labeling approach. Our results show that Org 27569 blocks conformational changes in CB1 that accompany G protein binding and/or activation, and thus inhibit formation of a fully active CB1 structure. The underlying mechanism behind this behavior is that simultaneous binding of Org 27569 produces a unique agonist-bound conformation, one that may resemble an intermediate structure formed on the pathway to full receptor activation.

  3. Luminal leptin induces rapid inhibition of active intestinal absorption of glucose mediated by sodium-glucose cotransporter 1.

    Science.gov (United States)

    Ducroc, Robert; Guilmeau, Sandra; Akasbi, Khalil; Devaud, Hélène; Buyse, Marion; Bado, André

    2005-02-01

    The effect of leptin on glucose transport was studied in rat jejunal mucosa in Ussing chambers. Leptin was added in the luminal or the serosal compartment before the tissues were challenged with 1, 10, or 50 mmol/l glucose. In response to 10 mmol/l glucose, the increase in short-circuit current (DeltaIsc) reached 26.8 +/- 2.1 microA/cm(2). Luminal addition of leptin dramatically decreased glucose-induced Isc (90.5% for 10 nmol/l leptin). Inhibition was maximal after 5 min and dose dependent (IC(50) = 0.13 nM). Western blot analysis showed that rapid inhibition of glucose-induced Isc by leptin was associated with a parallel decrease in the abundance of sodium-glucose transporter-1 in brush border membranes. Inhibition by luminal leptin of DeltaIsc was prevented by inhibitor of conventional protein kinase C isoforms. Serosal addition of leptin did not decrease glucose-induced Isc within 5 min and reached maximum after 10 min. The effect of leptin from serosal side was blocked by cholecystokinin (CCK) receptor-2 receptor antagonist YM022. Altogether, these data demonstrate that luminal leptin induces rapid inhibition of glucose entry into enterocyte. The slower action of leptin on the serosal side of mucosa seems indirect and is likely mediated by endogenous CCK. They demonstrate that gut leptin is a major regulator of rapid intestinal glucose transport.

  4. Conformal window manufacturing process development and demonstration for polycrystalline materials

    Science.gov (United States)

    Smith, Nathan E.; Gould, Alan R.; Hordin, Tom; Medicus, Kate; Walters, Mark; Brophy, Matthew; DeGroote Nelson, Jessica

    2013-09-01

    Conformal windows pose new and unique challenges to manufacturing due to the shape, measurement of, and requested hard polycrystalline materials. Their non-rotationally symmetric shape and high departure surfaces do not lend themselves to traditional optical fabrication processes. The hard crystalline materials are another challenge due to increased processing time and possibility of grain decoration. We have developed and demonstrated a process for manufacturing various conformal windows out of fused silica, glass, zinc-sulfide multispectral, and spinel. The current process involves CNC generation/grinding, VIBE polishing, and sub-aperture figure correction. The CNC generation step incorporates an ultrasonic assisted grinding machine; the machine settings and tool are being continuously optimized for minimal sub-surface damage and surface form error. In VIBE, polishing to less than 5 nm rms surface roughness while maintaining overall form error is accomplished with a full aperture conformal polishing tool and with rapid removal rates. The final sub-aperture polishing step corrects the overall form error. Currently we utilize our CMM for surface form measurement and have shown that we can produce spinel conformal windows with form error within +/-10 micrometers of the nominal shape, without grain decoration. This conformal window manufacturing process is continuously optimized for cost reduction and precision of the final optic.

  5. Social influence: compliance and conformity.

    Science.gov (United States)

    Cialdini, Robert B; Goldstein, Noah J

    2004-01-01

    This review covers recent developments in the social influence literature, focusing primarily on compliance and conformity research published between 1997 and 2002. The principles and processes underlying a target's susceptibility to outside influences are considered in light of three goals fundamental to rewarding human functioning. Specifically, targets are motivated to form accurate perceptions of reality and react accordingly, to develop and preserve meaningful social relationships, and to maintain a favorable self-concept. Consistent with the current movement in compliance and conformity research, this review emphasizes the ways in which these goals interact with external forces to engender social influence processes that are subtle, indirect, and outside of awareness.

  6. Conformational quiescence of ADAMTS-13 prevents proteolytic promiscuity.

    Science.gov (United States)

    South, K; Freitas, M O; Lane, D A

    2016-10-01

    Essentials Recently, ADAMTS-13 has been shown to undergo substrate induced conformation activation. Conformational quiescence of ADAMTS-13 may serve to prevent off-target proteolysis in plasma. Conformationally active ADAMTS-13 variants are capable of proteolysing the Aα chain of fibrinogen. This should be considered as ADAMTS-13 variants are developed as potential therapeutic agents. Click to hear Dr Zheng's presentation on structure function and cofactor-dependent regulation of ADAMTS-13 SUMMARY: Background Recent work has revealed that ADAMTS-13 circulates in a 'closed' conformation, only fully interacting with von Willebrand factor (VWF) following a conformational change. We hypothesized that this conformational quiescence also maintains the substrate specificity of ADAMTS-13 and that the 'open' conformation of the protease might facilitate proteolytic promiscuity. Objectives To identify a novel substrate for a constitutively active gain of function (GoF) ADAMTS-13 variant (R568K/F592Y/R660K/Y661F/Y665F). Methods Fibrinogen proteolysis was characterized using SDS PAGE and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Fibrin formation was monitored by turbidity measurements and fibrin structure visualized by confocal microscopy. Results ADAMTS-13 exhibits proteolytic activity against the Aα chain of human fibrinogen, but this is only manifest on its conformational activation. Accordingly, the GoF ADAMTS-13 variant and truncated variants such as MDTCS exhibit this activity. The cleavage site has been determined by LC-MS/MS to be Aα chain Lys225-Met226. Proteolysis of fibrinogen by GoF ADAMTS-13 impairs fibrin formation in plasma-based assays, alters clot structure and increases clot permeability. Although GoF ADAMTS-13 does not appear to proteolyse preformed cross-linked fibrin, its proteolytic activity against fibrinogen increases the susceptibility of fibrin to tissue-type plasminogen activator (t-PA)-induced lysis by plasmin and increases the

  7. Cytokine-induced proapoptotic gene expression in insulin-producing cells is related to rapid, sustained, and nonoscillatory nuclear factor-kappaB activation

    DEFF Research Database (Denmark)

    Ortis, Fernanda; Cardozo, Alessandra K; Crispim, Daisy

    2006-01-01

    Cytokines, such as IL-1beta and TNF-alpha, contribute to pancreatic beta-cell death in type 1 diabetes mellitus. The transcription factor nuclear factor-kappaB (NF-kappaB) mediates cytokine-induced beta-cell apoptosis. Paradoxically, NF-kappaB has mostly antiapoptotic effects in other cell types......-kappaB activation in insulin-producing cells is more rapid, marked, and sustained than in fibroblasts, which correlates with a more pronounced activation of downstream genes and a proapoptotic outcome....

  8. Specific, sensitive, precise, and rapid functional chromogenic assay of activated first complement component (C1) in plasma

    DEFF Research Database (Denmark)

    Munkvad, S; Jespersen, J; Sidelmann, Johannes Jakobsen

    1990-01-01

    We present a new functional assay for the first complement component (C1) in plasma, based on its activation by inhibition of the C1-esterase inhibitor (C1-inh) when monospecific antiserum to C1-inh is added to the plasma. After maximal activation, we can determine the concentration of activated ...

  9. Patterns and conformations in molecularly thin films

    Science.gov (United States)

    Basnet, Prem B.

    Molecularly thin films have been a subject of great interest for the last several years because of their large variety of industrial applications ranging from micro-electronics to bio-medicine. Additionally, molecularly thin films can be used as good models for biomembrane and other systems where surfaces are critical. Many different kinds of molecules can make stable films. My research has considered three such molecules: a polymerizable phospholipid, a bent-core molecules, and a polymer. One common theme of these three molecules is chirality. The phospolipid molecules studied here are strongly chiral, which can be due to intrinsically chiral centers on the molecules and also due to chiral conformations. We find that these molecules give rise to chiral patterns. Bent-core molecules are not intrinsically chiral, but individual molecules and groups of molecules can show chiral structures, which can be changed by surface interactions. One major, unconfirmed hypothesis for the polymer conformation at surface is that it forms helices, which would be chiral. Most experiments were carried out at the air/water interface, in what are called Langmuir films. Our major tools for studying these films are Brewster Angle Microscopy (BAM) coupled with the thermodynamic information that can be deduced from surface pressure isotherms. Phospholipids are one of the important constituents of liposomes -- a spherical vesicle com-posed of a bilayer membrane, typically composed of a phospholipid and cholesterol bilayer. The application of liposomes in drug delivery is well-known. Crumpling of vesicles of polymerizable phospholipids has been observed. With BAM, on Langmuir films of such phospholipids, we see novel spiral/target patterns during compression. We have found that both the patterns and the critical pressure at which they formed depend on temperature (below the transition to a i¬‘uid layer). Bent-core liquid crystals, sometimes knows as banana liquid crystals, have drawn

  10. Youth Conformity Regarding Institutions and Media

    Directory of Open Access Journals (Sweden)

    Nikolay Ivantchev

    2012-10-01

    Full Text Available An experiment on conformity was carried out. The participants were 95 youths. The scale “Conformity – Autonomy” from I. Karagiozov’s questionnaire for locus of control (1998 was also used. The results indicated the prevalence of youth conformity regarding institutions and media. The different types of conformity were related to each other. The subjects’ gender and the experimentators’ gender mediated the connections between the both types of conformity. The female youths conformed more with institutions than the male youths, but there were not any significant gender differences in their conform behavior regarding media (magazines. More male youths conformed for the magazines when the experimentator was a woman. More female youths conformed for the magazines when the experimentator was a man.

  11. Defects in conformal field theory

    Energy Technology Data Exchange (ETDEWEB)

    Billò, Marco [Dipartimento di Fisica, Università di Torino, and Istituto Nazionale di Fisica Nucleare - sezione di Torino,Via P. Giuria 1 I-10125 Torino (Italy); Gonçalves, Vasco [Centro de Física do Porto,Departamento de Física e Astronomia Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); ICTP South American Institute for Fundamental Research Instituto de Física Teórica,UNESP - University Estadual Paulista,Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil); Lauria, Edoardo [Institute for Theoretical Physics, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Meineri, Marco [Perimeter Institute for Theoretical Physics,Waterloo, Ontario, N2L 2Y5 (Canada); Scuola Normale Superiore, and Istituto Nazionale di Fisica Nucleare - sezione di Pisa,Piazza dei Cavalieri 7 I-56126 Pisa (Italy)

    2016-04-15

    We discuss consequences of the breaking of conformal symmetry by a flat or spherical extended operator. We adapt the embedding formalism to the study of correlation functions of symmetric traceless tensors in the presence of the defect. Two-point functions of a bulk and a defect primary are fixed by conformal invariance up to a set of OPE coefficients, and we identify the allowed tensor structures. A correlator of two bulk primaries depends on two cross-ratios, and we study its conformal block decomposition in the case of external scalars. The Casimir equation in the defect channel reduces to a hypergeometric equation, while the bulk channel blocks are recursively determined in the light-cone limit. In the special case of a defect of codimension two, we map the Casimir equation in the bulk channel to the one of a four-point function without defect. Finally, we analyze the contact terms of the stress-tensor with the extended operator, and we deduce constraints on the CFT data. In two dimensions, we relate the displacement operator, which appears among the contact terms, to the reflection coefficient of a conformal interface, and we find unitarity bounds for the latter.

  12. Conformation analysis of oligomeric flavanoids

    Science.gov (United States)

    Jan P. Steynberg; E. Vincent Brandt; Daneel Ferreira; Carin A. Helfer; Wayne L. Mattice; Dominika Gornik; Richard W. Hemingway

    1995-01-01

    The profisetinidins are the most important polyflavanoids of commerce, making up the major constituents of wattle and quebracho tannins. Within the dimeric profisetinidins, substantial complexity exists because of stereo-, regio, rotational and conformational isomers. Definition of the stereochemistry of the upper and lower flavan units, the location of the...

  13. Conformal symmetry and holographic cosmology

    NARCIS (Netherlands)

    Bzowski, A.W.

    2013-01-01

    This thesis presents a novel approach to cosmology using gauge/gravity duality. Analysis of the implications of conformal invariance in field theories leads to quantitative cosmological predictions which are in agreement with current data. Furthermore, holographic cosmology extends the theory of

  14. Free fructose is conformationally locked.

    Science.gov (United States)

    Cocinero, Emilio J; Lesarri, Alberto; Écija, Patricia; Cimas, Álvaro; Davis, Benjamin G; Basterretxea, Francisco J; Fernández, José A; Castaño, Fernando

    2013-02-20

    Fructose has been examined under isolation conditions using a combination of UV ultrafast laser vaporization and Fourier-transform microwave (FT-MW) spectroscopy. The rotational spectra for the parent, all (six) monosubstituted (13)C species, and two single D species reveal unambiguously that the free hexoketose is conformationally locked in a single dominant β-pyranose structure. This six-membered-chair skeleton adopts a (2)C(5) configuration (equivalent to (1)C(4) in aldoses). The free-molecule structure sharply contrasts with the furanose form observed in biochemically relevant polysaccharides, like sucrose. The structure of free fructose has been determined experimentally using substitution and effective structures. The enhanced stability of the observed conformation is primarily attributed to a cooperative network of five intramolecular O-H···O hydrogen bonds and stabilization of both endo and exo anomeric effects. Breaking a single intramolecular hydrogen bond destabilizes the free molecule by more than 10 kJ mol(-1). The structural results are compared to ribose, recently examined with rotational resolution, where six different conformations coexist with similar conformational energies. In addition, several DFT and ab initio methods and basis sets are benchmarked with the experimental data.

  15. Exceptional and Spinorial Conformal Windows

    DEFF Research Database (Denmark)

    Mojaza, Matin; Pica, Claudio; Ryttov, Thomas

    2012-01-01

    We study the conformal window of gauge theories containing fermionic matter fields, where the gauge group is any of the exceptional groups with the fermions transforming according to the fundamental and adjoint representations and the orthogonal groups where the fermions transform according...

  16. Anomalous Dimensions of Conformal Baryons

    DEFF Research Database (Denmark)

    Pica, Claudio; Sannino, Francesco

    2016-01-01

    We determine the anomalous dimensions of baryon operators for the three color theory as function of the number of massless flavours within the conformal window to the maximum known order in perturbation theory. We show that the anomalous dimension of the baryon is controllably small, within...

  17. Rapid fluctuations in extracellular brain glucose levels induced by natural arousing stimuli and intravenous cocaine: fueling the brain during neural activation

    Science.gov (United States)

    Lenoir, Magalie

    2012-01-01

    Glucose, a primary energetic substrate for neural activity, is continuously influenced by two opposing forces that tend to either decrease its extracellular levels due to enhanced utilization in neural cells or increase its levels due to entry from peripheral circulation via enhanced cerebral blood flow. How this balance is maintained under physiological conditions and changed during neural activation remains unclear. To clarify this issue, enzyme-based glucose sensors coupled with high-speed amperometry were used in freely moving rats to evaluate fluctuations in extracellular glucose levels induced by brief audio stimulus, tail pinch (TP), social interaction with another rat (SI), and intravenous cocaine (1 mg/kg). Measurements were performed in nucleus accumbens (NAcc) and substantia nigra pars reticulata (SNr), which drastically differ in neuronal activity. In NAcc, where most cells are powerfully excited after salient stimulation, glucose levels rapidly (latency 2–6 s) increased (30–70 μM or 6–14% over baseline) by all stimuli; the increase differed in magnitude and duration for each stimulus. In SNr, where most cells are transiently inhibited by salient stimuli, TP, SI, and cocaine induced a biphasic glucose response, with the initial decrease (−20–40 μM or 5–10% below baseline) followed by a reboundlike increase. The critical role of neuronal activity in mediating the initial glucose response was confirmed by monitoring glucose currents after local microinjections of glutamate (GLU) or procaine (PRO). While intra-NAcc injection of GLU transiently increased glucose levels in this structure, intra-SNr PRO injection resulted in rapid, transient decreases in SNr glucose. Therefore, extracellular glucose levels in the brain change very rapidly after physiological and pharmacological stimulation, the response is structure specific, and the pattern of neuronal activity appears to be a critical factor determining direction and magnitude of physiological

  18. Rapid fluctuations in extracellular brain glucose levels induced by natural arousing stimuli and intravenous cocaine: fueling the brain during neural activation.

    Science.gov (United States)

    Kiyatkin, Eugene A; Lenoir, Magalie

    2012-09-01

    Glucose, a primary energetic substrate for neural activity, is continuously influenced by two opposing forces that tend to either decrease its extracellular levels due to enhanced utilization in neural cells or increase its levels due to entry from peripheral circulation via enhanced cerebral blood flow. How this balance is maintained under physiological conditions and changed during neural activation remains unclear. To clarify this issue, enzyme-based glucose sensors coupled with high-speed amperometry were used in freely moving rats to evaluate fluctuations in extracellular glucose levels induced by brief audio stimulus, tail pinch (TP), social interaction with another rat (SI), and intravenous cocaine (1 mg/kg). Measurements were performed in nucleus accumbens (NAcc) and substantia nigra pars reticulata (SNr), which drastically differ in neuronal activity. In NAcc, where most cells are powerfully excited after salient stimulation, glucose levels rapidly (latency 2-6 s) increased (30-70 μM or 6-14% over baseline) by all stimuli; the increase differed in magnitude and duration for each stimulus. In SNr, where most cells are transiently inhibited by salient stimuli, TP, SI, and cocaine induced a biphasic glucose response, with the initial decrease (-20-40 μM or 5-10% below baseline) followed by a reboundlike increase. The critical role of neuronal activity in mediating the initial glucose response was confirmed by monitoring glucose currents after local microinjections of glutamate (GLU) or procaine (PRO). While intra-NAcc injection of GLU transiently increased glucose levels in this structure, intra-SNr PRO injection resulted in rapid, transient decreases in SNr glucose. Therefore, extracellular glucose levels in the brain change very rapidly after physiological and pharmacological stimulation, the response is structure specific, and the pattern of neuronal activity appears to be a critical factor determining direction and magnitude of physiological

  19. Substance P induces rapid and transient membrane blebbing in U373MG cells in a p21-activated kinase-dependent manner.

    Directory of Open Access Journals (Sweden)

    John Meshki

    Full Text Available U373MG astrocytoma cells endogenously express the full-length neurokinin 1 receptor (NK1R. Substance P (SP, the natural ligand for NK1R, triggers rapid and transient membrane blebbing and we report that these morphological changes have different dynamics and intracellular signaling as compared to the changes that we have previously described in HEK293-NK1R cells. In both cell lines, the SP-induced morphological changes are Gq-independent, and they require the Rho, Rho-associated coiled-coil kinase (ROCK signaling pathway. Using confocal microscopy we have demonstrated that tubulin is phosphorylated subsequent to cell stimulation with SP and that tubulin accumulates inside the blebs. Colchicine, a tubulin polymerization inhibitor, blocked SP-induced blebbing in U373MG but not in HEK293-NK1R cells. Although p21-activated kinase (PAK is expressed in both cell lines, SP induced rapid phosphorylation of PAK in U373MG, but failed to phosphorylate PAK in HEK293-NK1R cells. The cell-permeable Rho inhibitor C3 transferase inhibited SP-induced PAK phosphorylation, but the ROCK inhibitor Y27632 had no effect on PAK phosphorylation, suggesting that Rho activates PAK in a ROCK-independent manner. Our study demonstrates that SP triggers rapid changes in cell morphology mediated by distinct intracellular signaling mechanisms in U373MG versus HEK293-NK1R cells.

  20. Conformal grasping using feedback controlled bubble actuator array

    Science.gov (United States)

    Carrigan, Wei; Stein, Richard; Mittal, Manoj; Wijesundara, Muthu B. J.

    2014-06-01

    This paper presents an implementation of a bubble actuator array (BAA) based active robotic skin, a modular system, onto existing low cost robotic end-effectors or prosthetic hands for conformal grasping of objects. The active skin is comprised of pneumatically controlled polyurethane rubber bubbles with overlaid sensors for feedback control. Sensor feedback allows the BAA based robotic skin to conformally grasp an object with an explicit uniform force distribution. The bubble actuator array reported here is capable of applying up to 4N of force at each point of contact and tested for conformally grasping objects with a radius of curvature up to 57.15mm. Once integrated onto a two-finger gripper with one degree of freedom (DOF), the active skin was shown to reduce point of contact forces of up to 50% for grasped objects.

  1. Rapid activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway by electroconvulsive shock in the rat prefrontal cortex is not associated with TrkB neurotrophin receptor activation

    DEFF Research Database (Denmark)

    Hansen, Henrik H; Rantamäki, Tomi P J; Larsen, Marianne Hald

    2007-01-01

    , are important pathways triggered by TrkB autophosphorylation. 2. We have previously observed that chemical antidepressants induce a rapid activation of TrkB signaling in the rodent prefrontal cortex (PFC), which is likely a consequence of the stimulatory effect of antidepressants on BDNF synthesis. However...

  2. Effect of protein crystal hydration on side chain conformational heterogeneity

    Science.gov (United States)

    Atakisi, Hakan; Moreau, David; Hopkins, Jesse; Thorne, Robert; Robert Thorne's Group Team

    The structure of protein crystals is determined in part by water-mediated interactions involving both protein surface-ordered (hydration) and bulk water, and so is sensitive to the relative humidity of the environment. Monoclinic lysozyme provides a remarkable model for studying structural changes induced by dehydration, as it maintains excellent order for relative humidities (r.h.) down to 5%, corresponding to solvent content of 9% by volume, much smaller than the 88% (22% by volume) at which lysozyme loses its enzymatic activity. Although the main chain conformation does not change significantly, the effect of dehydration on side chain conformations has not been systematically studied. High resolution (1.1 to 1.7 A) structural data sets for monoclinic lysozyme at r.h. between 99% and 11% have been analyzed to identify major and minor side chain conformers at each humidity, and to map out how the side chain conformational ensemble evolves with hydration. Modest dehydration produces comparable overall effects to cooling to T =100 K, but with conformational changes largely confined to solvent-exposed residues. The largest side chain conformation changes occur at humidities that deplete water within the first two hydration shells.

  3. Mapping the conformational space accessible to catechol-O-methyltransferase.

    Science.gov (United States)

    Ehler, Andreas; Benz, Jörg; Schlatter, Daniel; Rudolph, Markus G

    2014-08-01

    Methylation catalysed by catechol-O-methyltransferase (COMT) is the main pathway of catechol neurotransmitter deactivation in the prefrontal cortex. Low levels of this class of neurotransmitters are held to be causative of diseases such as schizophrenia, depression and Parkinson's disease. Inhibition of COMT may increase neurotransmitter levels, thus offering a route for treatment. Structure-based drug design hitherto seems to be based on the closed enzyme conformation. Here, a set of apo, semi-holo, holo and Michaelis form crystal structures are described that define the conformational space available to COMT and that include likely intermediates along the catalytic pathway. Domain swaps and sizeable loop movements around the active site testify to the flexibility of this enzyme, rendering COMT a difficult drug target. The low affinity of the co-substrate S-adenosylmethionine and the large conformational changes involved during catalysis highlight significant energetic investment to achieve the closed conformation. Since each conformation of COMT is a bona fide target for inhibitors, other states than the closed conformation may be promising to address. Crystallographic data for an alternative avenue of COMT inhibition, i.e. locking of the apo state by an inhibitor, are presented. The set of COMT structures may prove to be useful for the development of novel classes of inhibitors.

  4. Conformational analysis for some nonclassical antagonists of histamine H3 receptor

    Science.gov (United States)

    Borota, Ana; Mracec, Maria; Rad, Ramona; Ostopovici, Liliana; Mracec, Mircea

    A conformational search in vacuum for a series of 1,3-substituted pyrrolidine derivatives has been performed using the AMBER, AM1, PM3, and MNDO methods. Conformational analysis of the pyrrolidine ligands suggests that these compounds could have many conformers that populate the low-energy minima on the potential energy surface (PES). The conformational space occupied by the ligands is large and, in vacuum, the rotation barriers of different flexible bonds have energies between 0.5 and thousands of kcal/mol. By optimization, most conformers have energy barriers of 0-5 kcal/mol; thus, they could interconvert easily to obtain better interactions in the receptor active site. Optimized conformers having energy barriers of >5 kcal/mol display bad geometries with very large bond lengths and deformed rings. Shapes and heights of rotation barriers obtained through COSMO-AM1 single-point calculations in water are similar to those obtained from single-point calculations in vacuum. However, in water the energy barriers are lower, allowing most conformers to convert in other low-energy conformers. The best conformers in vacuum and in water are different: the gas phase best conformer has a helical shape, while the best conformer in water has an extended shape.

  5. CD154 as a potential early molecular biomarker for rapid quantification analysis of active Staphylococcus enterotoxin A

    Science.gov (United States)

    Staphylococcus aureus is a major bacterial pathogen producing a group of twenty-one enterotoxins (SEs). These enterotoxins have two separate but related biological activities, They cause gastroenteritis, and they function as a superantigens that activate large numbers of T cells. In the current stud...

  6. The role of non-rapid eye movement slow-wave activity in prefrontal metabolism across young and middle-aged adults.

    Science.gov (United States)

    Wilckens, Kristine A; Aizenstein, Howard J; Nofzinger, Eric A; James, Jeffrey A; Hasler, Brant P; Rosario-Rivera, Bedda L; Franzen, Peter L; Germain, Anne; Hall, Martica H; Kupfer, David J; Price, Julie C; Siegle, Greg J; Buysse, Daniel J

    2016-06-01

    Electroencephalographic slow-wave activity (0.5-4 Hz) during non-rapid eye movement (NREM) sleep is a marker for cortical reorganization, particularly within the prefrontal cortex. Greater slow wave activity during sleep may promote greater waking prefrontal metabolic rate and, in turn, executive function. However, this process may be affected by age. Here we examined whether greater NREM slow wave activity was associated with higher prefrontal metabolism during wakefulness and whether this relationship interacted with age. Fifty-two participants aged 25-61 years were enrolled into studies that included polysomnography and a (18) [F]-fluoro-deoxy-glucose positron emission tomography scan during wakefulness. Absolute and relative measures of NREM slow wave activity were assessed. Semiquantitative and relative measures of cerebral metabolism were collected to assess whole brain and regional metabolism, focusing on two regions of interest: the dorsolateral prefrontal cortex and the orbitofrontal cortex. Greater relative slow wave activity was associated with greater dorsolateral prefrontal metabolism. Age and slow wave activity interacted significantly in predicting semiquantitative whole brain metabolism and outside regions of interest in the posterior cingulate, middle temporal gyrus and the medial frontal gyrus, such that greater slow-wave activity was associated with lower metabolism in the younger participants and greater metabolism in the older participants. These results suggest that slow-wave activity is associated with cerebral metabolism during wakefulness across the adult lifespan within regions important for executive function. © 2016 European Sleep Research Society.

  7. Microwave-assisted multicomponent reactions for rapid synthesis of AIE-active fluorescent polymeric nanoparticles by post-polymerization method.

    Science.gov (United States)

    Cao, Qian-Yong; Jiang, Ruming; Liu, Meiying; Wan, Qing; Xu, Dazhuang; Tian, Jianwen; Huang, Hongye; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

    2017-11-01

    The development of simple and effective methods for synthesis of fluorescent polymeric nanoparticles (FPNs) with aggregation-induced emission (AIE) plays an important role for the biomedical applications of AIE-active FPNs. In present work, we developed a facile strategy for the fabrication of AIE-active FPNs by a post-polymerization method based on the microwave-assisted Kabachnik-Fields (KF) reaction, which can conjugate with poly(PEGMA-NH2), AIE-active dye (TPE-CHO) and diethyl phosphate (DP) under microwave irradiation within 5min. The characterization results confirm that PEGMA-TPE FPNs are successfully prepared through the microwave-assisted KF reaction. The resultant AIE-active FPNs show high water dispersity, intensive fluorescence and low cytotoxicity. These features make these AIE-active FPNs great potential for biomedical applications. Moreover, the microwave-assisted KF reaction is simple, fast, atom economy that should be a general strategy for the fabrication of various multifunctional AIE-active FPNs. We believe this work will open up a new avenue for the preparation of AIE-active functional materials with great potential for different applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Multiple Conformations of E. Coli Hsp90 in Solution: Insights Into the Conformational Dynamics of Hsp90

    Energy Technology Data Exchange (ETDEWEB)

    Krukenberg, K.A.; Forster, F.; Rice, L.M.; Sali, A.; Agard, D.A.

    2009-05-20

    Hsp90, an essential eukaryotic chaperone, depends upon its intrinsic ATPase activity for function. Crystal structures of the bacterial Hsp90 homolog, HtpG, and the yeast Hsp90 reveal large domain rearrangements between the nucleotide-free and the nucleotide-bound forms. We used small-angle X-ray scattering and recently developed molecular modeling methods to characterize the solution structure of HtpG and demonstrate how it differs from known Hsp90 conformations. In addition to this HtpG conformation, we demonstrate that under physiologically relevant conditions, multiple conformations coexist in equilibrium. In solution, nucleotide-free HtpG adopts a more extended conformation than observed in the crystal, and upon the addition of AMPPNP, HtpG is in equilibrium between this open state and a closed state that is in good agreement with the yeast AMPPNP crystal structure. These studies provide a unique view of Hsp90 conformational dynamics and provide a model for the role of nucleotide in effecting conformational change.

  9. NF-κB is activated in CD4+ iNKT cells by sickle cell disease and mediates rapid induction of adenosine A2A receptors.

    Directory of Open Access Journals (Sweden)

    Gene Lin

    Full Text Available Reperfusion injury following tissue ischemia occurs as a consequence of vaso-occlusion that is initiated by activation of invariant natural killer T (iNKT cells. Sickle cell disease (SDC results in widely disseminated microvascular ischemia and reperfusion injury as a result of vaso-occlusion by rigid and adhesive sickle red blood cells. In mice, iNKT cell activation requires NF-κB signaling and can be inhibited by the activation of anti-inflammatory adenosine A2A receptors (A2ARs. Human iNKT cells are divided into subsets of CD4+ and CD4- cells. In this study we found that human CD4+ iNKT cells, but not CD4- cells undergo rapid NF-κB activation (phosphorylation of NF-κB on p65 and induction of A2ARs (detected with a monoclonal antibody 7F6-G5-A2 during SCD painful vaso-occlusive crises. These findings indicate that SCD primarily activates the CD4+ subset of iNKT cells. Activation of NF-κB and induction of A2ARs is concordant, i.e. only CD4+ iNKT cells with activated NF-κB expressed high levels of A2ARs. iNKT cells that are not activated during pVOC express low levels of A2AR immunoreactivity. These finding suggest that A2AR transcription may be induced in CD4+ iNKT cells as a result of NF-κB activation in SCD. In order to test this hypothesis further we examined cultured human iNKT cells. In cultured cells, blockade of NF-κB with Bay 11-7082 or IKK inhibitor VII prevented rapid induction of A2AR mRNA and protein upon iNKT activation. In conclusion, NF-κB-mediated induction of A2ARs in iNKT cells may serve as a counter-regulatory mechanism to limit the extent and duration of inflammatory immune responses. As activated iNKT cells express high levels of A2ARs following their activation, they may become highly sensitive to inhibition by A2AR agonists.

  10. Structural studies of conformational changes of proteins upon phosphorylation: Structures of activated CheY, CheY-N16-FliM complex, and AAA + ATPase domain of NtrC1 in both inactive and active states

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seok-Yong [Univ. of California, Berkeley, CA (United States)

    2003-04-10

    Protein phosphorylation is a general mechanism for signal transduction as well as regulation of cellular function. Unlike phosphorylation in eukaryotic systems that uses Ser/Thr for the sites of modification, two-component signal transduction systems, which are prevalent in bacteria, archea, and lower eukaryotes, use an aspartate as the site of phosphorylation. Two-component systems comprise a histidine kinase and a receiver domain. The conformational change of the receiver domain upon phosphorylation leads to signal transfer to the downstream target, a process that had not been understood well at the molecular level. The transient nature of the phospho-Asp bond had made structural studies difficult. The discovery of an excellent analogue for acylphosphate, BeF3-, enabled structural study of activated receiver domains. The structure of activated Chemotaxis protein Y (CheY) was determined both by NMR spectroscopy and X-ray crystallography. These structures revealed the molecular basis of the conformational change that is coupled to phosphorylation. Phosphorylation of the conserved Asp residue in the active site allows hydrogen bonding of the T87 Oγ to phospho-aspartate, which in turn leads to the rotation of Y106 into the ''in'' position (termed Y-T coupling). The structure of activated CheY complexed with the 16 N-terminal residues of FliM (N16-FliM), its target, was also determined by X-ray crystallography and confirmed the proposed mechanism of activation (Y-T coupling). First, N16-FliM binds to the region on CheY that undergoes a significant conformational change. Second, the ''in'' position of Y106 presents a better binding surface for FliM because the sidechain of Y106 in the inactive form of CheY (''out'' position) sterically interferes with binding of N16-FliM. In addition to confirmation of Y-T coupling, the structure of the activated CheY-N16-FliM complex suggested that the

  11. Exchanging conformations of a hydroformylation catalyst structurally characterized using two-dimensional vibrational spectroscopy.

    Science.gov (United States)

    Panman, Matthijs R; Vos, Jannie; Bocokić, Vladica; Bellini, Rosalba; de Bruin, Bas; Reek, Joost H N; Woutersen, Sander

    2013-12-16

    Catalytic transition-metal complexes often occur in several conformations that exchange rapidly (rapidly exchanging solution conformations of the hydroformylation catalyst (xantphos)Rh(CO)2H using two-dimensional vibrational spectroscopy, a method that can be applied to any catalyst provided that the exchange between its conformers occurs on a time scale of a few picoseconds or slower. We find that, in one of the conformations, the OC-Rh-CO angle deviates significantly from the canonical value in a trigonal-bipyramidal structure. On the basis of complementary density functional calculations, we ascribe this effect to attractive van der Waals interaction between the CO and the xantphos ligand.

  12. Rapid green synthesis of silver and gold nanoparticles using Dendropanax morbifera leaf extract and their anticancer activities.

    Science.gov (United States)

    Wang, Chao; Mathiyalagan, Ramya; Kim, Yeon Ju; Castro-Aceituno, Veronica; Singh, Priyanka; Ahn, Sungeun; Wang, Dandan; Yang, Deok Chun

    2016-01-01

    Dendropanax morbifera Léveille is an oriental medicinal plant that is traditionally used in folk medicine and grows in a specific region of South Korea. We aimed to enhance the utilization of D. morbifera medicinal plants for synthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs). D. morbifera leaf extract acted as both a reducing and a stabilizing agent that rapidly synthesized Dendropanax AgNPs (D-AgNPs) and Dendropanax AuNPs (D-AuNPs). The D-AgNPs and D-AuNPs were characterized by ultraviolet-visible spectroscopy, energy dispersive X-ray analysis, elemental mapping, field emission transmission electron microscopy, X-ray diffraction, and dynamic light scattering. The characterizations revealed that the D-AgNPs and D-AuNPs were in polygon and hexagon shapes with average sizes of 100-150 nm and 10-20 nm, respectively. The important outcomes were the synthesis of AgNPs and AuNPs within 1 hour and 3 minutes, respectively, avoiding the subsequent processing for removal of any toxic components or for stabilizing the nanoparticles. Additionally, D-AgNPs and D-AuNPs were examined for cytotoxicity in a human keratinocyte cell line and in A549 human lung cancer cell line. The results indicated that D-AgNPs exhibited less cytotoxicity in the human keratinocyte cell line at 100 µg/mL after 48 hours. On the other hand, D-AgNPs showed potent cytotoxicity in the lung cancer cells at the same concentration after 48 hours, whereas D-AuNPs did not exhibit cytotoxicity in both cell lines at the same concentration. However, both D-AgNPs and D-AuNPs at 50 µg/mL enhanced the cytotoxicity of ginsenoside compound K at 25 µM after 48 hours of treatment compared with CK alone. We believe that this rapid green synthesis of D-AgNPs and D-AuNPs is a valuable addition to the applications of D. morbifera medicinal plant. D-AuNPs can be used as carriers for drug delivery and in cancer therapy due to their lack of normal cell cytotoxicity.

  13. Conformal Bootstrap in Mellin Space

    Science.gov (United States)

    Gopakumar, Rajesh; Kaviraj, Apratim; Sen, Kallol; Sinha, Aninda

    2017-02-01

    We propose a new approach towards analytically solving for the dynamical content of conformal field theories (CFTs) using the bootstrap philosophy. This combines the original bootstrap idea of Polyakov with the modern technology of the Mellin representation of CFT amplitudes. We employ exchange Witten diagrams with built-in crossing symmetry as our basic building blocks rather than the conventional conformal blocks in a particular channel. Demanding consistency with the operator product expansion (OPE) implies an infinite set of constraints on operator dimensions and OPE coefficients. We illustrate the power of this method in the ɛ expansion of the Wilson-Fisher fixed point by reproducing anomalous dimensions and, strikingly, obtaining OPE coefficients to higher orders in ɛ than currently available using other analytic techniques (including Feynman diagram calculations). Our results enable us to get a somewhat better agreement between certain observables in the 3D Ising model and the precise numerical values that have been recently obtained.

  14. Conformal FDTD modeling wake fields

    Energy Technology Data Exchange (ETDEWEB)

    Jurgens, T.; Harfoush, F.

    1991-05-01

    Many computer codes have been written to model wake fields. Here we describe the use of the Conformal Finite Difference Time Domain (CFDTD) method to model the wake fields generated by a rigid beam traveling through various accelerating structures. The non- cylindrical symmetry of some of the problems considered here requires the use of a three dimensional code. In traditional FDTD codes, curved surfaces are approximated by rectangular steps. The errors introduced in wake field calculations by such an approximation can be reduced by increasing the mesh size, therefore increasing the cost of computing. Another approach, validated here, deforms Ampere and Faraday contours near a media interface so as to conform to the interface. These improvements of the FDTD method result in better accuracy of the fields at asymptotically no computational cost. This method is also capable of modeling thin wires as found in beam profile monitors, and slots and cracks as found in resistive wall motions. 4 refs., 5 figs.

  15. Conformal gravity and "gravitational bubbles"

    CERN Document Server

    Berezin, V A; Eroshenko, Yu N

    2015-01-01

    We describe the general structure of the spherically symmetric solutions in the Weyl conformal gravity. The corresponding Bach equations are derived for the special type of metrics, which can be considered as the representative of the general class. The complete set of the pure vacuum solutions, consisting of two classes, is found. The first one contains the solutions with constant two-dimensional curvature scalar, and the representatives are the famous Robertson--Walker metrics. We called one of them the "gravitational bubbles", which is compact and with zero Weyl tensor. These "gravitational bubbles" are the pure vacuum curved space-times (without any material sources, including the cosmological constant), which are absolutely impossible in General Relativity. This phenomenon makes it easier to create the universe from "nothing". The second class consists of the solutions with varying curvature scalar. We found its representative as the one-parameter family, which can be conformally covered by the thee-para...

  16. Gel dosimetry for conformal radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G. [Department of Physics of the University and INFN, Milan (Italy)]. e-mail: grazia.gambarini@mi.infn.it

    2005-07-01

    With the continuum development of conformal radio therapies, aimed at delivering high dose to tumor tissue and low dose to the healthy tissue around, the necessities has appeared of suitable improvement of dosimetry techniques giving the possibility of obtaining dose images to be compared with diagnostic images. Also if wide software has been developed for calculating dose distributions in the fields of various radiotherapy units, experimental verifications are necessary, in particular in the case of complex geometries in