Science.gov

Sample records for msp63 complexes induce

  1. Visual reflex seizures induced by complex stimuli.

    PubMed

    Zifkin, Benjamin G; Inoue, Yushi

    2004-01-01

    Visual reflex seizures induced by complex stimuli may be triggered by patterned and flashing displays that are now ubiquitous. The seizures may be clinically generalized, but unilateral and bilateral myoclonic attacks also may be triggered, especially in patients with juvenile myoclonic epilepsy, and recently, clearly focal reflex occipital lobe seizures have been described. Some seizure-triggering properties of video displays can be identified, such as perceived brightness, pattern, flicker frequency, and color. Knowledge of these is useful in planning individual treatment and in designing regulations for screen content of television broadcasts or for other video displays. Some subjects will also be sensitive to cognitive or action-programming activation, especially when playing video games, and this can increase the chance of seizure triggering. Nonspecific factors such as sleep deprivation, prolonged exposure, and drug or alcohol use also may play a role in reflex seizure occurrence. PMID:14706042

  2. Photochemically induced transformations of transition complexes

    SciTech Connect

    Brown, J.E.

    1993-05-17

    Photolysis of the dinuclear complex ((n5-C5H5)Fe(CO)2)2 in CHCl3 results in the formation of (n5-c5H5)Fe(CO)2Cl through intermediate 17-electron radicals of the form (n5-C5H5)Fe(CO)2. The photolyses of the related diphosphine-bridged compounds ((n5-C5H5)Fe(CO)2-u-DPPX, where DPPX=DPPM, DPPE and DPPP and therefore are (Ph2P)2CH2, (Ph2P)2C2H, and (Ph2P)2C3H6 respectively), are described. The synthesis and photolysis of the analogous ruthenium DPPM dimer is also described. In contrast to the behavior of the simple iron dinuclear species, the DPPM and DPPE phosphine bridged compounds undergo photolysis in CHCl3 to yield products containing formyl substituted cyclopentadienyl rings. Details of the reactions studied and product characterizations using multinuclear NMR, IR and single crystal X-ray diffraction techniques are described. A possible mechanism for the formation of the formyl derivatives 5 is outlined. In the synthesis and purification of ((n5C5H5)Ru(CO))2-u-DPPM and the attempted synthesis of the ((n5-C5H5)Ru(CO))2-u-DPPE, two ruthenium monomers of the form (n5-C5H5)Ru(Cl)DPPX resulted. A possible reaction pathway for the synthesis of these two monomers as byproducts in the ruthenium phosphine dimer preparation is suggested. Full structural and spectral characterizations of the monomeric compounds are Included. Photosynthesis, Organometallics, Reimer-Tiemann.

  3. Hypnosedative-induced complex behaviours : incidence, mechanisms and management.

    PubMed

    Dolder, Christian R; Nelson, Michael H

    2008-01-01

    A number of news items and case reports describing complex behaviours (e.g. sleep driving, sleep cooking, sleep eating, sleep conversations, sleep sex) associated with the use of hypnosedative medications have recently received considerable attention. Regulatory agencies examining these reports have subsequently issued warnings regarding the potential of hypnosedative agents to produce complex behaviours. Despite these warnings, little is known about the likelihood, presentation, treatment or prevention of hypnosedative-induced complex behaviours. The purpose of this review is to evaluate the published evidence regarding the clinical presentation, incidence, mechanism and management of sleep-related behaviours induced by nonbenzodiazepine receptor agonists (NBRAs).Review of the literature identified ten published case reports of NBRA-induced complex behaviours involving 17 unique patients. Fifteen of the 17 patients described in the case reports had taken zolpidem, one had taken zaleplon and one had taken zopiclone. The complex behaviours most commonly reported were sleep eating, sleepwalking with object manipulation, sleep conversations, sleep driving, sleep sex and sleep shopping. Elevated serum concentrations resulting from increased medication dose or drug-drug interactions appeared to play a role in some but not all cases. Sex, age, previous medication exposure and concomitant disease states were not consistently found to be related to the risk of experiencing a medication-induced complex behaviour.From a pharmacological standpoint, enhancement of GABA activity at GABAA receptors (particularly alpha1-GABAA receptors) is a possible mechanism for hypnosedative complex behaviours and amnesia. Evidence suggests that complex behaviour risk may increase with both dose and binding affinity at alpha1-GABAA receptors. The amnesia that accompanies complex behaviours is possibly due to inhibition of consolidation of short- to long-term memory, suggesting that the risk

  4. Inducible cadmium binding complexes of cabbage and tobacco

    SciTech Connect

    Wagner, G.J.; Trotter, M.M.

    1982-01-01

    Cadmium complexes with apparent molecular weights of 10,000 were observed in aqueous extracts of Cd-treated cabbage (Brassica capitata L., cv. red danish) and tobacco (hybrid of Nicotiana glauca and N. langsdorffii) plants. The amount of complex (as Cd) recovered was found to be dependent on the concentration of the metal in the growth medium and the total time of exposure of plants to the metal. Induction of the complex at moderate levels of /sup 112/Cd exposure was monitored after labeling the complex with /sup 109/Cd in vitro. The constitutive nature of the ligand of the complex in cabbage and tobacco leaves was suggested when control plant extracts were exposed to /sup 109/Cd. Such extracts contained /sup 109/Cd, which eluted froom Sephadex G-50 in the region of Cd complex. Simultaneous labeling with /sup 112/Cd and /sup 35/S or /sup 32/P indicated that the complex contained sulfur but probably not phosphorus. The amount of /sup 35/S which eluted coincident with /sup 112/Cd complex increased during complex induction. No evidence was found for the presence of 10,000 molecular weight Cd complex in stem exudates (vascular sap) of Cd-treated plants. The results obtained are consistent with the presence in these tissues of a ligand which is both inducible and consitutive and binds Cd in mercaptide bonds. All of these properties and oters reported earlier, are characteristic of Cd-metallothionein formed in animals.

  5. Complex Chromosomal Rearrangements Induced in Vivo by Heavy Ions

    NASA Technical Reports Server (NTRS)

    Durante, M.; Ando, K.; Furusawa, G.; Obe, G.; George, K.; Cucinotta, F. A.

    2004-01-01

    It has been suggested that the ratio complex/simple exchanges can be used as a biomarker of exposure to high-LET radiation. We tested this hypothesis in vivo, by considering data from several studies that measured complex exchanges in peripheral blood from humans exposed to mixed fields of low- and high-LET radiation. In particular, we studied data from astronauts involved in long-term missions in low-Earth-orbit, and uterus cancer patients treated with accelerated carbon ions. Data from two studies of chromosomal aberrations in astronauts used blood samples obtained before and after space flight, and a third study used blood samples from patients before and after radiotherapy course. Similar methods were used in each study, where lymphocytes were stimulated to grow in vitro, and collected after incubation in either colcemid or calyculin A. Slides were painted with whole-chromosome DNA fluorescent probes (FISH), and complex and simple chromosome exchanges in the painted genome were classified separately. Complex-type exchanges were observed at low frequencies in control subjects, and in our test subjects before the treatment. No statistically significant increase in the yield of complex-type exchanges was induced by the space flight. Radiation therapy induced a high fraction of complex exchanges, but no significant differences could be detected between patients treated with accelerated carbon ions or X-rays. Complex chromosomal rearrangements do not represent a practical biomarker of radiation quality in our test subjects. Copyright 2003 S. Karger AG, Basel.

  6. Calculation of interaction-induced spectra using complex absorbing potentials

    SciTech Connect

    Gustafsson, Magnus; Antipov, Sergey V.

    2010-10-29

    A complex absorbing potential method is implemented for calculation of collision-induced spectra. The scheme provides a way to avoid the integration of the Schroedinger equation to very large separations of the collisional pair. The method is tested by reproducing a previously computed absorption spectrum for H-He at two different temperatures.

  7. Necroptosis-Inducing Rhenium(V) Oxo Complexes

    PubMed Central

    Suntharalingam, Kogularamanan; Awuah, Samuel G.; Bruno, Peter M.; Johnstone, Timothy C.; Wang, Fang; Lin, Wei; Zheng, Yao-Rong; Page, Julia E.; Hemann, Michael T.; Lippard, Stephen J.

    2015-01-01

    Rhenium(V) oxo complexes of general formula [ReO(OMe)(N^N)Cl2], where N^N = 4,7-diphenyl-1,10-phenanthroline, 1, or 3,4,7,8-tetramethyl-1,10-phenanthroline, 2, effectively kill cancer cells by triggering necroptsosis, a non-apoptotic form of cell death. Both complexes evoke necrosome (RIP1-RIP3)-dependent intracellular ROS production and propidium iodide uptake. The complexes also induce mitochondrial membrane potential depletion, a possible downstream effect of ROS production. Apparently, 1 and 2 are the first rhenium complexes to evoke cellular events consistent with programmed necrosis in cancer cells. Furthermore, 1 and 2 display low acute toxicity in C57BL/6 mice and reasonable stability in fresh human blood. PMID:25698398

  8. Potassium Channel Complex Autoimmunity Induced by Inhaled Brain Tissue Aerosol

    PubMed Central

    Meeusen, Jeffrey W.; Klein, Christopher J.; Pirko, Istvan; Haselkorn, Keegan E.; Kryzer, Thomas J.; Pittock, Sean J.; Lachance, Daniel H.; Dyck, P. James; Lennon, Vanda A.

    2011-01-01

    Objective Test the hypothesis that autoimmunity induced by inhalation of aerosolized brain tissue caused outbreaks of sensory-predominant polyradiculoneuropathy among swine abattoir employees in Midwestern USA Methods Mice were exposed intranasally, 5 days weekly, to liquefied brain tissue. Serum from exposed mice, patients and unaffected abattoir employees were analyzed for clinically pertinent neural autoantibodies. Results Patients, coworkers and mice exposed to liquefied brain tissue had an autoantibody profile dominated by neural cation channel IgGs. The most compelling link between patients and exposed mice was MRI evidence of grossly swollen spinal nerve roots. Autoantibody responses in patients and mice were dose-dependent and declined after antigen exposure ceased. Autoantibodies detected most frequently, and at high levels, bound to detergent-solubilized macromolecular complexes containing neuronal voltage-gated potassium channels ligated with a high affinity Kv1 channel antagonist, 125I-α-dendrotoxin. Exposed mice exhibited a behavioral phenotype consistent with potassium channel dysfunction recognized in drosophila with mutant (“shaker”) channels: reduced sensitivity to isoflurane-induced anesthesia. Pathological and electrophysiological findings in patients supported peripheral nerve hyperexcitability over destructive axonal loss. The pain-predominant symptoms were consistent with sensory nerve hyperexcitability Interpretation Our observations establish that inhaled neural antigens readily induce neurological autoimmunity and identify voltage-gated potassium channel complexes as a major immunogen. PMID:22451206

  9. Chelation-Induced Polymer Structural Hierarchy/Complexity in Water.

    PubMed

    Han, Jie; Zhou, Kaiyi; Zhu, Xuechao; Yu, Qiuping; Ding, Yi; Lu, Xinhua; Cai, Yuanli

    2016-08-01

    Understanding nanoscale structural hierarchy/complexity of hydrophilic flexible polymers is imperative because it can be viewed as an analogue to protein-alike superstructures. However, current understanding is still in infancy. Herein the first demonstration of nanoscale structural hierarchy/complexity via copper chelation-induced self-assembly (CCISA) is presented. Hierarchically-ordered colloidal networks and disks can be achieved by deliberate control of spacer length and solution pH. Dynamic light scattering, transmission electron microscopy, and atomic force microscopy demonstrate that CCISA underwent supramolecular-to-supracolloidal stepwise-growth mechanism, and underline amazing prospects to the hierarchically-ordered superstructures of hydrophilic flexible polymers in water. PMID:27219860

  10. DEMONSTRATION OF ELECTROCHEMICAL REMEDIATION TECHNOLOGIES-INDUCED COMPLEXATION

    SciTech Connect

    Barry L. Burks

    2002-12-01

    The Project Team is submitting this Topical Report on the results of its bench-scale demonstration of ElectroChemical Remediation Technologies (ECRTs) and in particular the Induced Complexation (ECRTs-IC) process for remediation of mercury contaminated soils at DOE Complex sites. ECRTs is an innovative, in-situ, geophysically based soil remediation technology with over 50 successful commercial site applications involving remediation of over two million metric tons of contaminated soils. ECRTs-IC has been successfully used to remediate 220 cu m of mercury-contaminated sediments in the Union Canal, Scotland. In that operation, ECRTs-IC reduced sediment total mercury levels from an average of 243 mg/kg to 6 mg/kg in 26 days of operation. The clean up objective was to achieve an average total mercury level in the sediment of 20 mg/kg.

  11. Polarization-induced resistive switching behaviors in complex oxide heterostructures

    NASA Astrophysics Data System (ADS)

    Wu, Lei; Zhang, Chao; Dong, Chunhui; Jia, Chenglong; Jiang, Changjun; Xue, Desheng

    2015-09-01

    Complex oxide heterostructures are fabricated by growing La0.67Ca0.33MnO3 films on ferroelectric 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 (011) single-crystal substrates. The nonvolatile or pulsed resistive switching behaviors induced by an electric field are achieved simultaneously. Further analyses indicate that the different resistive switching behaviors are resulted from co-control of piezostrain and polarization current effects. With decreasing in-plane read current from 0.1 mA to 0.001 mA, the polarization current effect gradually begins to play a more important role than the piezostrain effect. Consequently, the nonvolatile resistive switching behavior is converted to pulse resistive switching behavior. The results further enhance the application of complex oxides in multifunctional memory devices.

  12. Morphogenesis and propagation of complex cracks induced by thermal shocks.

    PubMed

    Bourdin, Blaise; Marigo, Jean-Jacques; Maurini, Corrado; Sicsic, Paul

    2014-01-10

    We study the genesis and the selective propagation of complex crack networks induced by thermal shock or drying of brittle materials. We use a quasistatic gradient damage model to perform large-scale numerical simulations showing that the propagation of fully developed cracks follows Griffith criterion and depends only on the fracture toughness, while crack morphogenesis is driven by the material's internal length. Our numerical simulations feature networks of parallel cracks and selective arrest in two dimensions and hexagonal columnar joints in three dimensions, without any hypotheses on cracks geometry, and are in good agreement with available experimental results. PMID:24483901

  13. Complexity Induced Lifshitz Ordering with Multifractal Antiscreening/Screening (CILOMAS)

    NASA Astrophysics Data System (ADS)

    Chang, Tom T. S.

    2016-04-01

    We demonstrate that renormalization-group effects of scale-running propagator-coupling constants due to classical fluctuations can induce antiscreening/screening and multifractal symmetry breakings among various helical and other ordered states of generalized Lifshitz character leading to novel phase-transition associated complexities in condensed matter physics and gravitational evolution. Such phenomenon can exhibit the sporadic and localized appearance of virtual particles and in the context of cosmological evolution, the coarse-grained scale-running of the gravitational constant G due to classical fluctuations may provide a partial explanation to the dark matter mystery.

  14. Numerical Simulation of Flow-Induced Structure in Complex Fluids

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takehiro

    2007-04-01

    It is important to investigate the flow-induced structure for the analysis of the mechanism of flow behavior of complex fluids. The present paper includes two topics in which the flow-induced structure is numerically investigated. The first topic treats the suspensions of disc-like particles under simple shear flows. Disc-like particles were modeled by oblate spheroid particles, and the Brownian dynamics simulation was performed for suspensions of the particles interacting via the Gay-Berne potential. This simulation confirmed that this model system was applicable to the analysis of flow of suspension of disc-like particles. The second one is the numerical simulation of the deformation behavior of a droplet in shear flows. The present simulation is the first step for the numerical simulation of the flow-induced structure in emulsions. This simulation can demonstrate the deformation behavior of droplet observed in experiments and predict effects of non-Newtonian property of fluids on the droplet deformation.

  15. Inducible and Acquired Clarithromycin Resistance in the Mycobacterium abscessus Complex

    PubMed Central

    Rubio, Marc; March, Francesca; Garrigó, Montserrat; Moreno, Carmen; Español, Montserrat; Coll, Pere

    2015-01-01

    Purpose Clarithromycin was considered the cornerstone for the treatment of Mycobacterium abscessus complex infections. Genetic resistance mechanisms have been described and many experts propose amikacin as an alternative. Nevertheless, clarithromycin has several advantages; therefore, it is necessary to identify the non-functional erm(41) allele to determine the most suitable treatment. The aims of this study were to characterize the molecular mechanisms of clarithromycin resistance in a collection of Mycobacterium abscessus complex isolates and to verify the relationship between these mechanisms and the antibiogram. Materials and Methods Clinical isolates of M. abscessus complex (n = 22) from 16 patients were identified using four housekeeping genes (rpoB, secA1, sodA and hsp65), and their genetic resistance was characterized by studying erm(41) and rrl genes. Nine strains were recovered from the clinical isolates and subjected to E-test and microdilution clarithromycin susceptibility tests, with readings at 3, 7 and 14 days. Results We classified 11/16 (68.8%) M. abscessus subsp. abscessus, 4/16 (25.0%) M. abscessus subsp. bolletii, and 1/16 (6.3%) M. abscessus subsp. massiliense. T28 erm(41) allele was observed in 8 Mycobacterium abscessus subps. abscessus and 3 Mycobacterium abscessus subsp. bolletii. One strain of M. abscessus subsp. bolletii had an erm(41) gene truncated and was susceptible to clarithromycin. No mutations were observed in rrl gene first isolates. In three patients, follow-up of initial rrl wild-type strains showed acquired resistance. Conclusions Most clinical isolates of M. abscessus complex had inducible resistance to clarithromycin and total absence of constitutive resistance. Our findings showed that the acquisition of resistance mutations in rrl gene was associated with functional and non-functional erm(41) gene. Caution is needed when using erm(41) sequencing alone to identify M. abscessus subspecies. This study reports an acquired

  16. Three-dimensional induced polarization data inversion for complex resistivity

    SciTech Connect

    Commer, M.; Newman, G.A.; Williams, K.H.; Hubbard, S.S.

    2011-03-15

    The conductive and capacitive material properties of the subsurface can be quantified through the frequency-dependent complex resistivity. However, the routine three-dimensional (3D) interpretation of voluminous induced polarization (IP) data sets still poses a challenge due to large computational demands and solution nonuniqueness. We have developed a flexible methodology for 3D (spectral) IP data inversion. Our inversion algorithm is adapted from a frequency-domain electromagnetic (EM) inversion method primarily developed for large-scale hydrocarbon and geothermal energy exploration purposes. The method has proven to be efficient by implementing the nonlinear conjugate gradient method with hierarchical parallelism and by using an optimal finite-difference forward modeling mesh design scheme. The method allows for a large range of survey scales, providing a tool for both exploration and environmental applications. We experimented with an image focusing technique to improve the poor depth resolution of surface data sets with small survey spreads. The algorithm's underlying forward modeling operator properly accounts for EM coupling effects; thus, traditionally used EM coupling correction procedures are not needed. The methodology was applied to both synthetic and field data. We tested the benefit of directly inverting EM coupling contaminated data using a synthetic large-scale exploration data set. Afterward, we further tested the monitoring capability of our method by inverting time-lapse data from an environmental remediation experiment near Rifle, Colorado. Similar trends observed in both our solution and another 2D inversion were in accordance with previous findings about the IP effects due to subsurface microbial activity.

  17. Calculation of complex DNA damage induced by ions

    NASA Astrophysics Data System (ADS)

    Surdutovich, Eugene; Gallagher, David C.; Solov'yov, Andrey V.

    2011-11-01

    This paper is devoted to the analysis of the complex damage of DNA irradiated by ions. The assessment of complex damage is important because cells in which it occurs are less likely to survive because the DNA repair mechanisms may not be sufficiently effective. We study the flux of secondary electrons through the surface of nucleosomes and calculate the radial dose and the distribution of clustered damage around the ion's path. The calculated radial dose distribution is compared to simulations. The radial distribution of the complex damage is found to be different from that of the dose. A comparison with experiments may solve the question of what is more lethal for the cell, damage complexity or absorbed energy. We suggest a way to calculate the probability of cell death based on the complexity of the damage. This work is done within the framework of the phenomenon-based multiscale approach to radiation damage by ions.

  18. Calculation of complex DNA damage induced by ions

    SciTech Connect

    Surdutovich, Eugene; Gallagher, David C.; Solov'yov, Andrey V.

    2011-11-15

    This paper is devoted to the analysis of the complex damage of DNA irradiated by ions. The assessment of complex damage is important because cells in which it occurs are less likely to survive because the DNA repair mechanisms may not be sufficiently effective. We study the flux of secondary electrons through the surface of nucleosomes and calculate the radial dose and the distribution of clustered damage around the ion's path. The calculated radial dose distribution is compared to simulations. The radial distribution of the complex damage is found to be different from that of the dose. A comparison with experiments may solve the question of what is more lethal for the cell, damage complexity or absorbed energy. We suggest a way to calculate the probability of cell death based on the complexity of the damage. This work is done within the framework of the phenomenon-based multiscale approach to radiation damage by ions.

  19. Rhenium complexes with visible-light-induced anticancer activity.

    PubMed

    Kastl, Anja; Dieckmann, Sandra; Wähler, Kathrin; Völker, Timo; Kastl, Lena; Merkel, Anna Lena; Vultur, Adina; Shannan, Batool; Harms, Klaus; Ocker, Matthias; Parak, Wolfgang J; Herlyn, Meenhard; Meggers, Eric

    2013-06-01

    Shedding light on the matter: Rhenium(I) indolato complexes with highly potent visible-light-triggered antiproliferative activity (complex 1: EC50 light=0.1 μM vs EC50 dark=100 μM) in 2D- and 3D-organized cancer cells are reported and can be traced back to an efficient generation of singlet oxygen, causing rapid morphological changes and an induction of apoptosis. PMID:23568508

  20. Statistics of complex eigenvalues in friction-induced vibration

    NASA Astrophysics Data System (ADS)

    Nobari, Amir; Ouyang, Huajiang; Bannister, Paul

    2015-03-01

    Self-excited vibrations appear in many mechanical systems with sliding contacts. There are several mechanisms whereby friction can cause the self-excited vibration to become unstable. Of these mechanisms, mode coupling is thought to be responsible for generating annoying high-frequency noise and vibration in brakes. Conventionally, in order to identify whether a system is stable or not, complex eigenvalue analysis is performed. However, what has recently received much attention of researchers is the variability and uncertainty of input variables in the stability analysis of self-excited vibrations. For this purpose, a second-order perturbation method is extended and employed in the current study. The moments of the output distribution along with its joint moment generating function are used for quantifying the statistics of the complex eigenvalues. Moreover, the eigen-derivatives required for the perturbation method are presented in a way that they can deal with the asymmetry of the stiffness matrix and non-proportional damping. Since the eigen-derivatives of such systems are complex-valued numbers, it is mathematically more informative and convenient to derive the statistics of the eigenvalues in a complex form, without decomposing them into two real-valued real and imaginary parts. Then, the variance and pseudo-variance of the complex eigenvalues are used for determining the statistics of the real and imaginary parts. The reliability and robustness of the system in terms of stability can also be quantified by the approximated output distribution.

  1. Light induced electron transfer reactions of metal complexes

    SciTech Connect

    Sutin, N.; Creutz, C.

    1980-01-01

    Properties of the excited states of tris(2,2'-bipyridine) and tris(1,10-phenanthroline) complexes of chromium(III), iron(II), ruthenium(II), osmium(II), rhodium(III), and iridium(III) are described. The electron transfer reactions of the ground and excited states are discussed and interpreted in terms of the driving force for the reaction and the distortions of the excited states relative to the corresponding ground states. General considerations relevant to the conversion of light into chemical energy are presented and progress in the use of polypyridine complexes to effect the light decomposition of water into hydrogen and oxygen is reviewed.

  2. Unusually long-lived light-induced metastable state in a thermochromic copper(II) complex.

    PubMed

    Takahashi, Kazuyuki; Nakajima, Rie; Gu, Zhong-ze; Yoshiki, Hajime; Fujishima, Akira; Sato, Osamu

    2002-08-01

    We report the first observation of a color change from red to purple for a thermochromic complex, [Cu(dieten)2](BF4)2 (dieten = N,N-diethylethylenediamine), which is induced by illuminating with UV light. PMID:12170790

  3. Light uncages a copper complex to induce nonapoptotic cell death.

    PubMed

    Kumbhar, Anupa A; Franks, Andrew T; Butcher, Raymond J; Franz, Katherine J

    2013-03-25

    Cu3G is a Cu(II) complex of a photoactive tetradentate ligand that is cleaved upon UV irradiation to release Cu. Here we show that the cytotoxicity of Cu3G increases in response to brief UV stimulation to result in extensive cytoplasmic vacuolization that is indicative of nonapoptotic cell death. PMID:23417227

  4. Collective chaos induced by structures of complex networks

    NASA Astrophysics Data System (ADS)

    Yang, Huijie; Zhao, Fangcui; Wang, Binghong

    2006-05-01

    Mapping a complex network of N coupled identical oscillators to a quantum system, the nearest neighbor level spacing (NNLS) distribution is used to identify collective chaos in the corresponding classical dynamics on the complex network. The classical dynamics on an Erdos-Renyi network with the wiring probability pER⩽1/N is in the state of collective order, while that on an Erdos-Renyi network with pER>1/N in the state of collective chaos. The dynamics on a WS Small-world complex network evolves from collective order to collective chaos rapidly in the region of the rewiring probability pr∈[0.0,0.1], and then keeps chaotic up to pr=1.0. The dynamics on a Growing Random Network (GRN) is in a special state deviates from order significantly in a way opposite to that on WS small-world networks. Each network can be measured by a couple values of two parameters (β,η).

  5. Particle-induced amorphization of complex ceramics. Final report

    SciTech Connect

    Ewing, R.C.; Wang, L.M.

    1998-08-01

    The crystalline-to-amorphous (c-a) phase transition is of fundamental importance. Particle irradiations provide an important, highly controlled means of investigating this phase transformation and the structure of the amorphous state. The interaction of heavy-particles with ceramics is complex because these materials have a wide range of structure types, complex compositions, and because chemical bonding is variable. Radiation damage and annealing can produce diverse results, but most commonly, single crystals become aperiodic or break down into a polycrystalline aggregate. The authors continued the studies of the transition from the periodic-to-aperiodic state in natural materials that have been damaged by {alpha}-recoil nuclei in the uranium and thorium decay series and in synthetic, analogous structures. The transition from the periodic to aperiodic state was followed by detailed x-ray diffraction analysis, in-situ irradiation/transmission electron microscopy, high resolution transmission electron microscopy, extended x-ray absorption fine structure spectroscopy/x-ray absorption near edge spectroscopy and other spectroscopic techniques. These studies were completed in conjunction with bulk irradiations that can be completed at Los Alamos National Laboratory or Sandia National Laboratories. Principal questions addressed in this research program included: (1) What is the process at the atomic level by which a ceramic material is transformed into a disordered or aperiodic state? (2) What are the controlling effects of structural topology, bond-type, dose rate, and irradiation temperature on the final state of the irradiated material? (3) What is the structure of the damaged material? (4) What are the mechanisms and kinetics for the annealing of interstitial and aggregate defects in these irradiated ceramic materials? (5) What general criteria may be applied to the prediction of amorphization in complex ceramics?

  6. Flow induced dust acoustic shock waves in a complex plasma

    NASA Astrophysics Data System (ADS)

    Jaiswal, Surabhi; Bandyopadhyay, Pintu; Sen, Abhijit

    2015-11-01

    We report on experimental observations of particle flow induced large amplitude shock waves in a dusty plasma. These dust acoustic shocks (DAS) are observed for strongly supersonic flows and have been studied in a U-shaped Dusty Plasma Experimental (DPEx) device for charged kaolin dust in a background of Argon plasma. The strong flow of the dust fluid is induced by adjusting the pumping speed and neutral gas flow into the device. An isolated copper wire mounted on the cathode acts as a potential barrier to the flow of dust particles. A sudden change of the dust density near the potential hill is used to trigger the onset of high velocity dust acoustic shocks. The dynamics of the shocks are captured by fast video pictures of the structures that are illuminated by a laser sheet beam. The physical characteristics of the shock are delineated from a parametric scan of their dynamical properties over a range of plasma parameters and flow speeds. Details of these observations and a physical explanation based on model calculations will be presented.

  7. Complex nanoprecipitate structures induced by irradiation in immiscible alloy systems

    NASA Astrophysics Data System (ADS)

    Shu, Shipeng; Bellon, P.; Averback, R. S.

    2013-04-01

    We investigate the fundamentals of compositional patterning induced by energetic particle irradiation in model A-B substitutional binary alloys using kinetic Monte Carlo simulations. The study focuses on a type of nanostructure that was recently observed in dilute Cu-Fe and Cu-V alloys, where precipitates form within precipitates, a morphology that we term “cherry-pit” structures. The simulations show that the domain of stability of these cherry-pit structures depends on the thermodynamic and kinetic asymmetry between the A and B elements. In particular, both lower solubilities and diffusivities of A in B compared to those of B in A favor the stabilization of these cherry-pit structures for A-rich average compositions. The simulation results are rationalized by extending the analytic model introduced by Frost and Russell for irradiation-induced compositional patterning so as to include the possible formation of pits within precipitates. The simulations indicate also that the pits are dynamical structures that undergo nearly periodic cycles of nucleation, growth, and absorption by the matrix.

  8. Complexation-induced supramolecular assembly drives metal-ion extraction.

    PubMed

    Ellis, Ross J; Meridiano, Yannick; Muller, Julie; Berthon, Laurence; Guilbaud, Philippe; Zorz, Nicole; Antonio, Mark R; Demars, Thomas; Zemb, Thomas

    2014-09-26

    Combining experiment with theory reveals the role of self-assembly and complexation in metal-ion transfer through the water-oil interface. The coordinating metal salt Eu(NO3)3 was extracted from water into oil by a lipophilic neutral amphiphile. Molecular dynamics simulations were coupled to experimental spectroscopic and X-ray scattering techniques to investigate how local coordination interactions between the metal ion and ligands in the organic phase combine with long-range interactions to produce spontaneous changes in the solvent microstructure. Extraction of the Eu(3+)-3(NO3(-)) ion pairs involves incorporation of the "hard" metal complex into the core of "soft" aggregates. This seeds the formation of reverse micelles that draw the water and "free" amphiphile into nanoscale hydrophilic domains. The reverse micelles interact through attractive van der Waals interactions and coalesce into rod-shaped polynuclear Eu(III) -containing aggregates with metal centers bridged by nitrate. These preorganized hydrophilic domains, containing high densities of O-donor ligands and anions, provide improved Eu(III) solvation environments that help drive interfacial transfer, as is reflected by the increasing Eu(III) partitioning ratios (oil/aqueous) despite the organic phase approaching saturation. For the first time, this multiscale approach links metal-ion coordination with nanoscale structure to reveal the free-energy balance that drives the phase transfer of neutral metal salts. PMID:25169678

  9. Complexity Induced Anisotropic Bimodal Intermittent Turbulence in Space Plasmas

    NASA Technical Reports Server (NTRS)

    Chang, Tom; Tam, Sunny W. Y.; Wu, Cheng-Chin

    2004-01-01

    The "physics of complexity" in space plasmas is the central theme of this exposition. It is demonstrated that the sporadic and localized interactions of magnetic coherent structures arising from the plasma resonances can be the source for the coexistence of nonpropagating spatiotemporal fluctuations and propagating modes. Non-Gaussian probability distribution functions of the intermittent fluctuations from direct numerical simulations are obtained and discussed. Power spectra and local intermittency measures using the wavelet analyses are presented to display the spottiness of the small-scale turbulent fluctuations and the non-uniformity of coarse-grained dissipation that can lead to magnetic topological reconfigurations. The technique of the dynamic renormalization group is applied to the study of the scaling properties of such type of multiscale fluctuations. Charged particle interactions with both the propagating and nonpropagating portions of the intermittent turbulence are also described.

  10. Force-induced remodelling of proteins and their complexes

    PubMed Central

    Chen, Yun; Radford, Sheena E; Brockwell, David J

    2015-01-01

    Force can drive conformational changes in proteins, as well as modulate their stability and the affinity of their complexes, allowing a mechanical input to be converted into a biochemical output. These properties have been utilised by nature and force is now recognised to be widely used at the cellular level. The effects of force on the biophysical properties of biological systems can be large and varied. As these effects are only apparent in the presence of force, studies on the same proteins using traditional ensemble biophysical methods can yield apparently conflicting results. Where appropriate, therefore, force measurements should be integrated with other experimental approaches to understand the physiological context of the system under study. PMID:25710390

  11. Synthesis, Characterization, In Vitro Cytotoxicity, and Apoptosis-Inducing Properties of Ruthenium(II) Complexes

    PubMed Central

    Xu, Li; Zhong, Nan-Jing; Xie, Yang-Yin; Huang, Hong-Liang; Jiang, Guang-Bin; Liu, Yun-Jun

    2014-01-01

    Two new Ru(II) complexes, [Ru(bpy)2(FAMP)](ClO4)2 1 and 2, are synthesized and characterized by elemental analysis, electrospray mass spectrometry, and 1H nuclear magnetic resonance. The in vitro cytotoxicities and apoptosis-inducing properties of these complexes are extensively studied. Complexes 1 and 2 exhibit potent antiproliferative activities against a panel of human cancer cell lines. The cell cycle analysis shows that complexes 1 and 2 exhibit effective cell growth inhibition by triggering G0/G1 phase arrest and inducing apoptosis by mitochondrial dysfunction. The in vitro DNA binding properties of the two complexes are investigated by different spectrophotometric methods and viscosity measurements. PMID:24804832

  12. RIP1 and RIP3 complex regulates radiation-induced programmed necrosis in glioblastoma.

    PubMed

    Das, Arabinda; McDonald, Daniel G; Dixon-Mah, Yaenette N; Jacqmin, Dustin J; Samant, Vikram N; Vandergrift, William A; Lindhorst, Scott M; Cachia, David; Varma, Abhay K; Vanek, Kenneth N; Banik, Naren L; Jenrette, Joseph M; Raizer, Jeffery J; Giglio, Pierre; Patel, Sunil J

    2016-06-01

    Radiation-induced necrosis (RN) is a relatively common side effect of radiation therapy for glioblastoma. However, the molecular mechanisms involved and the ways RN mechanisms differ from regulated cell death (apoptosis) are not well understood. Here, we compare the molecular mechanism of cell death (apoptosis or necrosis) of C6 glioma cells in both in vitro and in vivo (C6 othotopically allograft) models in response to low and high doses of X-ray radiation. Lower radiation doses were used to induce apoptosis, while high-dose levels were chosen to induce radiation necrosis. Our results demonstrate that active caspase-8 in this complex I induces apoptosis in response to low-dose radiation and inhibits necrosis by cleaving RIP1 and RI. When activation of caspase-8 was reduced at high doses of X-ray radiation, the RIP1/RIP3 necrosome complex II is formed. These complexes induce necrosis through the caspase-3-independent pathway mediated by calpain, cathepsin B/D, and apoptosis-inducing factor (AIF). AIF has a dual role in apoptosis and necrosis. At high doses, AIF promotes chromatinolysis and necrosis by interacting with histone H2AX. In addition, NF-κB, STAT-3, and HIF-1 play a crucial role in radiation-induced inflammatory responses embedded in a complex inflammatory network. Analysis of inflammatory markers in matched plasma and cerebrospinal fluid (CSF) isolated from in vivo specimens demonstrated the upregulation of chemokines and cytokines during the necrosis phase. Using RIP1/RIP3 kinase specific inhibitors (Nec-1, GSK'872), we also establish that the RIP1-RIP3 complex regulates programmed necrosis after either high-dose radiation or TNF-α-induced necrosis requires RIP1 and RIP3 kinases. Overall, our data shed new light on the relationship between RIP1/RIP3-mediated programmed necrosis and AIF-mediated caspase-independent programmed necrosis in glioblastoma. PMID:26684801

  13. Lac repressor: Crystallization of intact tetramer and its complexes with inducer and operator DNA

    SciTech Connect

    Pace, H.C.; Lu, P. ); Lewis, M. Smith Kline and French Labs., King of Prussia, PA )

    1990-03-01

    The intact lac repressor tetramer, which regulates expression of the lac operon in Escherichia coli, has been crystallized in the native form, with an inducer, and in a ternary complex with operator DNA and an anti-inducer. The crystals without DNA diffract to better than 3.5 {angstrom}. They belong to the monoclinic space group C2 and have cell dimensions a = 164.7 {angstrom}, b = 75.6 {angstrom}, and c = 161.2 {angstrom}, with {alpha} = {gamma} = 90{degree} and {beta} = 125.5{degree}. Cocrystals have been obtained with a number of different lac operator-related DNA fragments. The complex with a blunt-ended 16-base-pair strand yielded tetragonal bipyramids that diffract to 6.5 {angstrom}. These protein-DNA cocrystals crack upon exposure to the gratuitous inducer isopropyl {beta}-D-thiogalactoside, suggesting a conformational change in the repressor-operator complex.

  14. Vacancy complexes induce long-range ferromagnetism in GaN

    SciTech Connect

    Zhang, Zhenkui; Schwingenschlögl, Udo E-mail: Iman.Roqan@kaust.edu.sa; Roqan, Iman S. E-mail: Iman.Roqan@kaust.edu.sa

    2014-11-14

    By means of density functional theory, we argue that ferromagnetism in GaN can be induced by vacancy complexes. Spin polarization originates from the charge compensation between neutral N and Ga vacancies. Defect formation energy calculations predict that a vacancy complex of two positively charged N vacancies and one doubly negative Ga vacancy is likely to form. This defect complex induces a net moment of 1 μ{sub B}, which is localized around the negative Ga center and exhibits pronounced in-plane ferromagnetic coupling. In contrast to simple Ga vacancy induced ferromagnetism, the proposed picture is in line with the fact that N vacancies have a low formation energy. Formation energies indicate mutual stabilization of the intrinsic defects in GaN.

  15. Infrared spectroscopic studies on reaction induced conformational changes in the NADH ubiquinone oxidoreductase (complex I).

    PubMed

    Hellwig, Petra; Kriegel, Sébastien; Friedrich, Thorsten

    2016-07-01

    Redox-dependent conformational changes are currently discussed to be a crucial part of the reaction mechanism of the respiratory complex I. Specialized difference Fourier transform infrared techniques allow the detection of side-chain movements and minute secondary structure changes. For complex I, (1)H/(2)H exchange kinetics of the amide modes revealed a better accessibility of the backbone in the presence of NADH and quinone. Interestingly, the presence of phospholipids, that is crucial for the catalytic activity of the isolated enzyme complex, changes the overall conformation. When comparing complex I samples from different species, very similar electrochemically induced FTIR difference spectra and very similar rearrangements are reported. Finally, the information obtained with variants and from Zn(2+) inhibited samples for the conformational reorganization of complex I upon electron transfer are discussed in this review. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt. PMID:26702948

  16. Heptachlor induced mitochondria-mediated cell death via impairing electron transport chain complex III

    SciTech Connect

    Hong, Seokheon; Kim, Joo Yeon; Hwang, Joohyun; Shin, Ki Soon; Kang, Shin Jung

    2013-08-09

    Highlights: •Heptachlor inhibited mitochondrial electron transport chain complex III activity. •Heptachlor promoted generation of reactive oxygen species. •Heptachlor induced Bax activation. •Heptachlor induced mitochondria-mediated and caspase-dependent apoptosis. -- Abstract: Environmental toxins like pesticides have been implicated in the pathogenesis of Parkinson’s disease (PD). Epidemiological studies suggested that exposures to organochlorine pesticides have an association with an increased PD risk. In the present study, we examined the mechanism of toxicity induced by an organochlorine pesticide heptachlor. In a human dopaminergic neuroblastoma SH-SY5Y cells, heptachlor induced both morphological and functional damages in mitochondria. Interestingly, the compound inhibited mitochondrial electron transport chain complex III activity. Rapid generation of reactive oxygen species and the activation of Bax were then detected. Subsequently, mitochondria-mediated, caspase-dependent apoptosis followed. Our results raise a possibility that an organochlorine pesticide heptachlor can act as a neurotoxicant associated with PD.

  17. Surface induced dissociation yields substructure of Methanosarcina thermophila 20S proteasome complexes

    PubMed Central

    Ma, Xin; Loo, Joseph A.; Wysocki, Vicki H.

    2015-01-01

    Native mass spectrometry (MS) and surface induced dissociation (SID) have been applied to study the stoichiometry and quaternary structure of non-covalent protein complexes. In this study, Methanosarcina thermophila 20S proteasome, which consists of four stacked heptameric rings (α7β7β7α7 symmetry), has been selected to explore the SID dissociation pattern of a complicated stacked ring protein complex. SID produces both α and β subunits while collision induced dissociation (CID) produces only highly charged α subunit. In addition, the charge reduced 20S proteasome produces the α7β7 fragment, reflecting the stacked ring topology of the complex. The combination of SID and charge reduction is shown to be a powerful tool for the study of protein complex structure. PMID:26005366

  18. Both Complexity and Location of DNA Damage Contribute to Cellular Senescence Induced by Ionizing Radiation

    PubMed Central

    Zhang, Xurui; Ye, Caiyong; Sun, Fang; Wei, Wenjun; Hu, Burong; Wang, Jufang

    2016-01-01

    Persistent DNA damage is considered as a main cause of cellular senescence induced by ionizing radiation. However, the molecular bases of the DNA damage and their contribution to cellular senescence are not completely clear. In this study, we found that both heavy ions and X-rays induced senescence in human uveal melanoma 92–1 cells. By measuring senescence associated-β-galactosidase and cell proliferation, we identified that heavy ions were more effective at inducing senescence than X-rays. We observed less efficient repair when DNA damage was induced by heavy ions compared with X-rays and most of the irreparable damage was complex of single strand breaks and double strand breaks, while DNA damage induced by X-rays was mostly repaired in 24 hours and the remained damage was preferentially associated with telomeric DNA. Our results suggest that DNA damage induced by heavy ion is often complex and difficult to repair, thus presents as persistent DNA damage and pushes the cell into senescence. In contrast, persistent DNA damage induced by X-rays is preferentially associated with telomeric DNA and the telomere-favored persistent DNA damage contributes to X-rays induced cellular senescence. These findings provide new insight into the understanding of high relative biological effectiveness of heavy ions relevant to cancer therapy and space radiation research. PMID:27187621

  19. Both Complexity and Location of DNA Damage Contribute to Cellular Senescence Induced by Ionizing Radiation.

    PubMed

    Zhang, Xurui; Ye, Caiyong; Sun, Fang; Wei, Wenjun; Hu, Burong; Wang, Jufang

    2016-01-01

    Persistent DNA damage is considered as a main cause of cellular senescence induced by ionizing radiation. However, the molecular bases of the DNA damage and their contribution to cellular senescence are not completely clear. In this study, we found that both heavy ions and X-rays induced senescence in human uveal melanoma 92-1 cells. By measuring senescence associated-β-galactosidase and cell proliferation, we identified that heavy ions were more effective at inducing senescence than X-rays. We observed less efficient repair when DNA damage was induced by heavy ions compared with X-rays and most of the irreparable damage was complex of single strand breaks and double strand breaks, while DNA damage induced by X-rays was mostly repaired in 24 hours and the remained damage was preferentially associated with telomeric DNA. Our results suggest that DNA damage induced by heavy ion is often complex and difficult to repair, thus presents as persistent DNA damage and pushes the cell into senescence. In contrast, persistent DNA damage induced by X-rays is preferentially associated with telomeric DNA and the telomere-favored persistent DNA damage contributes to X-rays induced cellular senescence. These findings provide new insight into the understanding of high relative biological effectiveness of heavy ions relevant to cancer therapy and space radiation research. PMID:27187621

  20. HMGB1-DNA Complex-induced Autophagy Limits AIM2 Inflammasome Activation through RAGE

    PubMed Central

    Liu, Liying; Yang, Minghua; Kang, Rui; Yu, Yan; Dai, Yunpen; Gao, Fei; Wang, Hongmei; Sun, Xiaojun; Li, Xiuli; Li, Jianhua; Wang, Haichao; Cao, Lizhi; Tang, Daolin

    2014-01-01

    High mobility group box 1 (HMGB1) is a prototype damage-associated molecular pattern (DAMP) that can induce inflammatory and immune responses alone as well as in combination with other molecules such as DNA. However, the intricate molecular mechanisms underlying HMGB1-DNA complex-mediated innate immune response remains largely elusive. In this study, we demonstrated that HMGB1-DNA complex initially induced absent in melanoma 2 (AIM2)-dependent inflammasome activation, and promoted rapid release of inflammasome-dependent early proinflammatory cytokines such as interleukin 1β (IL-1β). Subsequently, HMGB1-DNA complex stimulated an ATG5-dependent cellular degradation process, autophagy, which was paralleled by a cessation of AIM2 inflammasome activation and IL-1β release. These HMGB1-DNA complex-induced inflammasome activation and autophagy were both dependent on the receptor for advanced glycation endproducts (RAGE) that recognizes a wide array of ligands (including HMGB1 and DNA). Thus, autophagy may function as a negative counter-regulatory mechanism for HMGB1-DNA complex-induced inflammasome activation, and provide a checkpoint to limit the development of inflammation. PMID:24971542

  1. Geomorphology and failure history of the earthquake-induced Farmington Siding landslide complex, Davis County, Utah

    SciTech Connect

    Lowe, M.; Harty, K.M. )

    1993-04-01

    The Farmington Siding landslide complex covers an area of 19.5 km[sup 2] in central Davis County. First identified and mapped in the 1970s, the feature was classified by previous researchers as a liquefaction-induced lateral spread based on surface geomorphology and exposures on the landslide complex. This was the first landslide in Utah to be attributed to earthquake-induced liquefaction. Geomorphic and geologic evidence indicate that the Farmington Sliding landslide complex likely consists of liquefaction-induced landslides that failed by means of both flow failure and lateral spreading. The landslide complex is located in an area underlain primarily by fine-grained deposits of Pleistocene Lake Bonneville and Holocene Great Salt Lake. Geomorphic features of the landslide complex include main and minor scarps, hummocks, closed depressions, and transverse lineaments. The main scarp consists mostly of a series of arcuate scallops near the left flank of the landslide, but it is a relatively linear, single scarp near the right flank of the landslide. Hummocks and closed depressions are most common near the head region of the landslide complex. Failure of the Farmington Sliding landslide complex has occurred at least twice. The older, distal portion of the landslide complex is cut by the Gilbert shoreline of the Bonneville lake cycle, indicating that landsliding occurred more than 10,000 years ago. In the younger portion of the landslide complex, landsliding has disrupted the Gilbert shoreline. Radiocarbon age estimates from trenches on a hummock near the main scarp of the younger landslide indicate that slope failure occurred sometime between about 2,730 [+-] 370 cal. yr B.P. and 4,530 [+-] 300 cal. yr B.P., possibly during the penultimate or antepenultimate surface-faulting earthquake on the Weber segment of the Wasatch fault zone.

  2. cAMP prevents TNF-induced apoptosis through inhibiting DISC complex formation in rat hepatocytes

    PubMed Central

    Bhattacharjee, Rajesh; Xiang, Wenpei; Wang, Yinna; Zhang, Xiaoying; Billiar, Timothy R.

    2013-01-01

    Tumor necrosis factor α (TNF) is a pleiotropic proinflammatory cytokine that plays a role in immunity and the control of cell proliferation, cell differentiation, and apoptosis. The pleiotropic nature of TNF is due to the formation of different signaling complexes upon the binding of TNF to its receptor, TNF receptor type 1 (TNFR1). TNF induces apoptosis in various mammalian cells when the cells are co-treated with a transcription inhibitor like actinomycin D (ActD). When TNFR1 is activated, it recruits an adaptor protein, TNF receptor-associated protein with death domain (TRADD), through its cytoplasmic death effector domain (DED). TRADD, in turn, recruits other signaling proteins, including TNF receptor-associated protein 2 (TRAF2) and receptor-associated protein kinase (RIPK) 1, to form a complex. Subsequently, this complex combines with FADD and procaspase-8, converts into a death-inducing signaling complex (DISC) to induce apoptosis. Cyclic AMP (cAMP) is a second messenger that regulates various cellular processes such as cell proliferation, gene expression, and apoptosis. cAMP analogues are reported to act as anti-apoptotic agents in various cell types, including hepatocytes. We found that a cAMP analogue, dibutyryl cAMP (db-cAMP), inhibits TNF + ActD-induced apoptosis in rat hepatocytes. The protein kinase A (PKA) inhibitor KT-5720 reverses this inhibitory effect of cAMP on apoptosis. Cytoprotection by cAMP involves down-regulation of various apoptotic signal regulators like TRADD and FADD and inhibition of caspase-8 and caspase-3 cleavage. We also found that cAMP exerts its affect at the proximal level of TNF signaling by inhibiting the formation of the DISC complex upon the binding of TNF to TNFR1. In conclusion, our study shows that cAMP prevents TNF + ActD-induced apoptosis in rat hepatocytes by inhibiting DISC complex formation. PMID:22634003

  3. Isoniazid-induced cell death is precipitated by underlying mitochondrial complex I dysfunction in mouse hepatocytes.

    PubMed

    Lee, Kang Kwang; Fujimoto, Kazunori; Zhang, Carmen; Schwall, Christine T; Alder, Nathan N; Pinkert, Carl A; Krueger, Winfried; Rasmussen, Theodore; Boelsterli, Urs A

    2013-12-01

    Isoniazid (INH) is an antituberculosis drug that has been associated with idiosyncratic liver injury in susceptible patients. The underlying mechanisms are still unclear, but there is growing evidence that INH and/or its major metabolite, hydrazine, may interfere with mitochondrial function. However, hepatic mitochondria have a large reserve capacity, and minor disruption of energy homeostasis does not necessarily induce cell death. We explored whether pharmacologic or genetic impairment of mitochondrial complex I may amplify mitochondrial dysfunction and precipitate INH-induced hepatocellular injury. We found that INH (≤ 3000 μM) did not induce cell injury in cultured mouse hepatocytes, although it decreased hepatocellular respiration and ATP levels in a concentration-dependent fashion. However, coexposure of hepatocytes to INH and nontoxic concentrations of the complex I inhibitors rotenone (3 μM) or piericidin A (30 nM) resulted in massive ATP depletion and cell death. Although both rotenone and piericidin A increased MitoSox-reactive fluorescence, Mito-TEMPO or N-acetylcysteine did not attenuate the extent of cytotoxicity. However, preincubation of cells with the acylamidase inhibitor bis-p-nitrophenol phosphate provided protection from hepatocyte injury induced by rotenone/INH (but not rotenone/hydrazine), suggesting that hydrazine was the cell-damaging species. Indeed, we found that hydrazine directly inhibited the activity of solubilized complex II. Hepatocytes isolated from mutant Ndufs4(+/-) mice, although featuring moderately lower protein expression levels of this complex I subunit in liver mitochondria, exhibited unchanged hepatic complex I activity and were therefore not sensitized to INH. These data indicate that underlying inhibition of complex I, which alone is not acutely toxic, can trigger INH-induced hepatocellular injury. PMID:23911619

  4. The mitochondrial TOM complex modulates bax-induced apoptosis in Drosophila.

    PubMed

    Colin, J; Garibal, J; Mignotte, B; Guénal, I

    2009-02-20

    Bax is a pro-apoptotic member of the Bcl-2 family proteins involved in the release of apoptogenic factors from mitochondria to the cytosol. Recently, it has been shown both in mammals and yeast that Bax insertion in the mitochondrial outer membrane involves at least two distinct mechanisms, one of which uses the TOM complex. Here, we show that in Drosophila, heterozygous loss of function mutations of Tom22 or Tom70, two receptors of the TOM complex, attenuates bax-induced phenotypes in vivo. These results argue that the TOM complex may be used as a mitochondrial Bax receptor in Drosophila. PMID:19138672

  5. Endosomal Sorting Complex Required for Transport (ESCRT) Complexes Induce Phase-separated Microdomains in Supported Lipid Bilayers*

    PubMed Central

    Boura, Evzen; Ivanov, Vassili; Carlson, Lars-Anders; Mizuuchi, Kiyoshi; Hurley, James H.

    2012-01-01

    The endosomal sorting complex required for transport (ESCRT) system traffics ubiquitinated cargo to lysosomes via an unusual membrane budding reaction that is directed away from the cytosol. Here, we show that human ESCRT-II self-assembles into clusters of 10–100 molecules on supported lipid bilayers. The ESCRT-II clusters are functional in that they bind to ubiquitin and the ESCRT-III subunit VPS20 at nanomolar concentrations on membranes with the same stoichiometries observed in solution and in crystals. The clusters only form when cholesterol is included in the lipid mixture at >10 mol %. The clusters induce the formation of ordered membrane domains that exclude the dye 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindodicarbo-cyanine perchlorate. These results show that ESCRT complexes are capable of inducing lateral lipid phase separation under conditions where the lipids themselves do not spontaneously phase-separate. This property could facilitate ESCRT-mediated membrane budding. PMID:22718754

  6. Three-Dimensional Topological Field Theory Induced from Generalized Complex Structure

    NASA Astrophysics Data System (ADS)

    Ikeda, Noriaki

    We construct a three-dimensional topological sigma model which is induced from a generalized complex structure on a target generalized complex manifold. This model is constructed from maps from a three-dimensional manifold X to an arbitrary generalized complex manifold M. The theory is invariant under the diffeomorphism on the worldvolume and the b-transformation on the generalized complex structure. Moreover the model is manifestly invariant under the mirror symmetry. We derive from this model the Zucchini's two-dimensional topological sigma model with a generalized complex structure as a boundary action on ∂X. As a special case, we obtain three-dimensional realization of a WZ-Poisson manifold.

  7. ox-LDL induces endothelial dysfunction by promoting Arp2/3 complex expression.

    PubMed

    Tang, Yao; Zhao, Jianting; Shen, Liming; Jin, Yiqi; Zhang, Zhixuan; Xu, Guoxiong; Huang, Xianchen

    2016-06-24

    Oxidized low-density lipoproteins (ox-LDL) play a critical role in endothelial injury including cytoskeleton reorganization, which is closely related to actin-related protein 2/3 (Arp2/3) complex. The aim of this study was to investigate the role of Arp2/3 complex in ox-LDL-induced endothelial dysfunction. In this study, we found that Arp2 and Arp3 expression was increased under atherosclerotic conditions both in ApoE-/- mice and in ox-LDL-stimulated human coronary artery endothelial cells (HCAECs). Arp2/3 complex inhibitor CK666 significantly reduced ox-LDL-induced ROS generation and cytoskeleton reorganization, and increased NO release in HCAECs. Pretreatment with LOX-1- but not CD36-blocking antibody markedly decreased ox-LDL-induced Arp2 and Arp3 expression. Moreover, Rac-1 siRNA remarkably suppressed ox-LDL-stimulated Arp2 and Arp3 expression. Additionally, CK666 reduced endothelial nitric oxide synthase (eNOS) expression and atherosclerotic lesions in ApoE-/- mice. Collectively, ox-LDL induces endothelial dysfunction by activating LOX-1/Rac-1 signaling and upregulating Arp2/3 complex expression. PMID:27181356

  8. Prothrombin complex concentrate for warfarin-induced bleeding in a patient with a mechanical aortic valve

    PubMed Central

    Kar, Rahul; Abel, Erik; Burcham, Pamela; Firstenberg, Michael S.

    2013-01-01

    Reversal of anticoagulation-induced bleeding in the perioperative period can be challenging, particularly with an unstable patient with a mechanical valve. We present a case of life-threatening bleeding successfully managed with a prothrombin complex concentrate as an alternative to fresh frozen plasma. PMID:23667067

  9. Near-infrared-induced electron transfer of an uranyl macrocyclic complex without energy transfer to dioxygen.

    PubMed

    Davis, Christina M; Ohkubo, Kei; Ho, I-Ting; Zhang, Zhan; Ishida, Masatoshi; Fang, Yuanyuan; Lynch, Vincent M; Kadish, Karl M; Sessler, Jonathan L; Fukuzumi, Shunichi

    2015-04-21

    Photoexcitation of dichloromethane solutions of an uranyl macrocyclic complex with cyclo[1]furan[1]pyridine[4]-pyrrole () at the near-infrared (NIR) band (1177 nm) in the presence of electron donors and acceptors resulted in NIR-induced electron transfer without producing singlet oxygen via energy transfer. PMID:25791126

  10. Solvent-induced reversible solid-state colour change of an intramolecular charge-transfer complex.

    PubMed

    Li, Ping; Maier, Josef M; Hwang, Jungwun; Smith, Mark D; Krause, Jeanette A; Mullis, Brian T; Strickland, Sharon M S; Shimizu, Ken D

    2015-10-11

    A dynamic intramolecular charge-transfer (CT) complex was designed that displayed reversible colour changes in the solid-state when treated with different organic solvents. The origins of the dichromatism were shown to be due to solvent-inclusion, which induced changes in the relative orientations of the donor pyrene and acceptor naphthalenediimide units. PMID:26299357

  11. Identifying the magnetoconductance responses by the induced charge transfer complex states in pentacene-based diodes

    NASA Astrophysics Data System (ADS)

    Huang, Wei-Shun; Lee, Tsung-Hsun; Guo, Tzung-Fang; Huang, J. C. A.; Wen, Ten-Chin

    2012-07-01

    We investigate the magnetoconductance (MC) responses in photocurrent, unipolar injection, and bipolar injection regimes in pentacene-based diodes. Both photocurrent and bipolar injection contributed MC responses show large difference in MC line shape, which are attributed to triplet-polaron interaction modulated by the magnetic field dependent singlet fission and the intersystem crossing of the polaron pair, respectively. By blending 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane into pentacene, all the MC responses are suppressed but the MC response at unipolar injection regime is enhanced, which is attributed to the induced charge transfer complex states (CT complex states). This work identify the MC responses between single carrier contributed MC and exciton related MC by the induced CT complex states.

  12. The inducible elongin A elongation activation domain: structure, function and interaction with the elongin BC complex.

    PubMed Central

    Aso, T; Haque, D; Barstead, R J; Conaway, R C; Conaway, J W

    1996-01-01

    The elongin (SIII) complex strongly stimulates the rate of elongation by RNA polymerase II by suppressing transient pausing by polymerase at many sites along the DNA. Elongin (SIII) is composed of a transcriptionally active A subunit and two small regulatory B and C subunits, which bind stably to each other to form a binary complex that interacts with elongin A and strongly induces its transcriptional activity. The elongin (SIII) complex is a potential target for negative regulation by the von Hippel-Lindau (VHL) tumor suppressor protein, which is capable of binding stably to the elongin BC complex and preventing it from activating elongin A. Here, we identify an elongin A domain sufficient for activation of elongation and demonstrate that it is a novel type of inducible activator that targets the RNA polymerase II elongation complex and is evolutionarily conserved in species as distantly related as Caenorhabditis elegans and man. In addition, we demonstrate that both the elongin A elongation activation domain and the VHL tumor suppressor protein interact with the elongin BC complex through a conserved elongin BC binding site motif that is essential for induction of elongin A activity by elongin BC and for tumor suppression by the VHL protein. Images PMID:8896449

  13. cAMP prevents TNF-induced apoptosis through inhibiting DISC complex formation in rat hepatocytes

    SciTech Connect

    Bhattacharjee, Rajesh; Xiang, Wenpei; Wang, Yinna; Zhang, Xiaoying

    2012-06-22

    Highlights: Black-Right-Pointing-Pointer cAMP blocks cell death induced by TNF and actinomycin D in cultured hepatocytes. Black-Right-Pointing-Pointer cAMP blocks NF-{kappa}B activation induced by TNF and actinomycin D. Black-Right-Pointing-Pointer cAMP blocks DISC formation following TNF and actinomycin D exposure. Black-Right-Pointing-Pointer cAMP blocks TNF signaling at a proximal step. -- Abstract: Tumor necrosis factor {alpha} (TNF) is a pleiotropic proinflammatory cytokine that plays a role in immunity and the control of cell proliferation, cell differentiation, and apoptosis. The pleiotropic nature of TNF is due to the formation of different signaling complexes upon the binding of TNF to its receptor, TNF receptor type 1 (TNFR1). TNF induces apoptosis in various mammalian cells when the cells are co-treated with a transcription inhibitor like actinomycin D (ActD). When TNFR1 is activated, it recruits an adaptor protein, TNF receptor-associated protein with death domain (TRADD), through its cytoplasmic death effector domain (DED). TRADD, in turn, recruits other signaling proteins, including TNF receptor-associated protein 2 (TRAF2) and receptor-associated protein kinase (RIPK) 1, to form a complex. Subsequently, this complex combines with FADD and procaspase-8, converts into a death-inducing signaling complex (DISC) to induce apoptosis. Cyclic AMP (cAMP) is a second messenger that regulates various cellular processes such as cell proliferation, gene expression, and apoptosis. cAMP analogues are reported to act as anti-apoptotic agents in various cell types, including hepatocytes. We found that a cAMP analogue, dibutyryl cAMP (db-cAMP), inhibits TNF + ActD-induced apoptosis in rat hepatocytes. The protein kinase A (PKA) inhibitor KT-5720 reverses this inhibitory effect of cAMP on apoptosis. Cytoprotection by cAMP involves down-regulation of various apoptotic signal regulators like TRADD and FADD and inhibition of caspase-8 and caspase-3 cleavage. We also found

  14. Light Induced Processes for the Synthesis of Polymers With Complex Structures

    NASA Astrophysics Data System (ADS)

    Durmaz, Yasemin Y.; Tasdelen, M. Atilla; Aydogan, Binnur; Kahveci, Muhammet U.; Yagci, Yusuf

    Light induced reactions are based on the absorption of light that excites the electrons of a molecule and can, under favorable circumstances, lead to dissociation, isomerization, abstraction, electron or energy transfer, and bond formation. These reactions have been the subject of many studies in various fields including organic chemistry, molecular biology, electronics etc. Light induced reactions can advantageously be utilized in the field of polymer chemistry. Among them, light induced polymerization is of enormous commercial importance. Techniques such as curing of coatings on wood, metal and paper, adhesives, printing inks and photoresists are based on photopolymerization. There are some other interesting applications, including production of laser video discs and curing of acrylate dental fillings. In this chapter, general methods for the light induced polymerization processes involving radical and ionic reactions are described. Special emphasize is devoted to their application to more complex macromolecular structures such as block, graft and star copolymers, and polymer nanocomposites based on clay and metal.

  15. Comparison of different substrates for laser-induced electron transfer desorption/ionization of metal complexes

    NASA Astrophysics Data System (ADS)

    Grechnikov, A. A.; Georgieva, V. B.; Donkov, N.; Borodkov, A. S.; Pento, A. V.; Raicheva, Z. G.; Yordanov, Tc A.

    2016-03-01

    Four different substrates, namely, graphite, tungsten, amorphous silicon (α-Si) and titanium dioxide (TiO2) films, were compared in view of the laser-induced electron transfer desorption/ionization (LETDI) of metal coordination complexes. A rhenium complex with 8-mercaptoquinoline, a copper complex with diphenylthiocarbazone and chlorophyll A were studied as the test analytes. The dependencies of the ion yield and the surface temperature on the incident radiation fluence were investigated experimentally and theoretically. The temperature was estimated using the numerical solution of a one-dimensional heat conduction problem with a heat source distributed in time and space. It was found that at the same temperature, the ion yield from the different substrates varies in the range of three orders of magnitude. The direct comparison of all studied substrates revealed that LETDI from the TiO2 and α-Si films offer a better choice for producing molecular ions of metal coordination complexes.

  16. The L-Z complexity of exercise-induced muscle fatigue based on acoustic myographye

    NASA Astrophysics Data System (ADS)

    Yijian, Min; Xinyuan, Liu; Tingting, Wang

    2014-01-01

    The mechanism of exercise fatigue was investigated during exercise using L-Z complexity of non-linear analysis. Muscle fatigue was induced in the sitting position by lifting the heel under a load. An acoustic myogram of the gastrocnemius was obtained until exhaustion. The different modes of the speed responses were calculated using the L-Z complexity method, which analyzes muscle fibers participation, while the exercise is in progress. The L-Z complexity decreased incrementally with decreases in muscle strength, reaching a minimum value when the muscle was exhausted. Our data indicate that the L-Z complexity method is easy to use and effective at revealing the dynamic characteristics and variations of exercise fatigue. This method could be used to monitor sports training.

  17. Chronic Repression of mTOR Complex 2 Induces Changes in the Gut Microbiota of Diet-induced Obese Mice.

    PubMed

    Jung, Mi-Ja; Lee, Jina; Shin, Na-Ri; Kim, Min-Soo; Hyun, Dong-Wook; Yun, Ji-Hyun; Kim, Pil Soo; Whon, Tae Woong; Bae, Jin-Woo

    2016-01-01

    Alterations in the gut microbiota play a crucial role in host physiology and metabolism; however, the molecular pathways underlying these changes in diet-induced obesity are unclear. Mechanistic target of rapamycin (mTOR) signaling pathway is associated with metabolic disorders such as obesity and type 2 diabetes (T2D). Therefore, we examined whether changes in the regulation of mTOR signaling induced by diet (a high-fat diet [HFD] or normal-chow diet) and/or therapeutics (resveratrol [a specific inhibitor of mTOR complex 1] or rapamycin [an inhibitor of both mTOR complex 1 and 2]) altered the composition of the gut microbiota in mice. Oral administration of resveratrol prevented glucose intolerance and fat accumulation in HFD-fed mice, whereas rapamycin significantly impaired glucose tolerance and exacerbated intestinal inflammation. The abundance of Lactococcus, Clostridium XI, Oscillibacter, and Hydrogenoanaerobacterium increased under the HFD condition; however, the abundance of these species declined after resveratrol treatment. Conversely, the abundance of unclassified Marinilabiliaceae and Turicibacter decreased in response to a HFD or rapamycin. Taken together, these results demonstrated that changes in the composition of intestinal microbiota induced by changes in mTOR activity correlate with obese and diabetic phenotypes. PMID:27471110

  18. Chronic Repression of mTOR Complex 2 Induces Changes in the Gut Microbiota of Diet-induced Obese Mice

    PubMed Central

    Jung, Mi-Ja; Lee, Jina; Shin, Na-Ri; Kim, Min-Soo; Hyun, Dong-Wook; Yun, Ji-Hyun; Kim, Pil Soo; Whon, Tae Woong; Bae, Jin-Woo

    2016-01-01

    Alterations in the gut microbiota play a crucial role in host physiology and metabolism; however, the molecular pathways underlying these changes in diet-induced obesity are unclear. Mechanistic target of rapamycin (mTOR) signaling pathway is associated with metabolic disorders such as obesity and type 2 diabetes (T2D). Therefore, we examined whether changes in the regulation of mTOR signaling induced by diet (a high-fat diet [HFD] or normal-chow diet) and/or therapeutics (resveratrol [a specific inhibitor of mTOR complex 1] or rapamycin [an inhibitor of both mTOR complex 1 and 2]) altered the composition of the gut microbiota in mice. Oral administration of resveratrol prevented glucose intolerance and fat accumulation in HFD-fed mice, whereas rapamycin significantly impaired glucose tolerance and exacerbated intestinal inflammation. The abundance of Lactococcus, Clostridium XI, Oscillibacter, and Hydrogenoanaerobacterium increased under the HFD condition; however, the abundance of these species declined after resveratrol treatment. Conversely, the abundance of unclassified Marinilabiliaceae and Turicibacter decreased in response to a HFD or rapamycin. Taken together, these results demonstrated that changes in the composition of intestinal microbiota induced by changes in mTOR activity correlate with obese and diabetic phenotypes. PMID:27471110

  19. Role of oxidative stress in Geldanamycin-induced cytotoxicity and disruption of Hsp90 signaling complex

    PubMed Central

    Clark, Christina B.; Rane, Madhavi J.; Mehdi, Delphine El; Miller, Cynthia J.; Sachleben, Leroy R.; Gozal, Evelyne

    2009-01-01

    Heat shock protein 90 (Hsp90) is a chaperone protein regulating PC-12 cell survival by binding and stabilizing Akt, Raf-1, and Cdc37. Hsp90 inhibitor Geldanamycin (GA) cytotoxicity has been attributed to disruption of Hsp90 binding, and the contribution of oxidative stress generated by its quinone group has not been studied in this context. Reactive oxygen species (ROS) and cell survival were assessed in PC-12 cells exposed to GA or Menadione (MEN), and Akt, Raf-1, and Cdc37 expression and binding to Hsp90 were determined. GA disrupted Hsp90 binding and increased ROS production starting at 1h, and cell death occurred at 6h, inhibited by N-acetyl cysteine (NAC) without preventing dissociation of proteins. At 24h, NAC prevented cytotoxicity and Hsp90 complex disruption. However MnTBAP antioxidant treatment failed to inhibit GA cytotoxicity, suggesting that NAC acts by restoring gluthathione. In contrast, 24h MEN induced cytotoxicity without disrupting Hsp90 binding. GA and MEN decreased Hsp90-binding proteins expression, and proteasomal inhibition prevented MEN, but not GA-induced degradation. In conclusion, while MEN cytotoxicity is mediated by ROS and proteasomal degradation, GA-induced cytotoxicity requires ROS but induces HSP90 complex dissociation and proteasome-independent protein degradation. These differences between MEN and GA-induced cytotoxicity, may allow more specific targeting of cancer cells. PMID:19703551

  20. Surface Induced Dissociation Yields Quaternary Substructure of Refractory Noncovalent Phosphorylase B and Glutamate Dehydrogenase Complexes

    NASA Astrophysics Data System (ADS)

    Ma, Xin; Zhou, Mowei; Wysocki, Vicki H.

    2014-03-01

    Ion mobility (IM) and tandem mass spectrometry (MS/MS) coupled with native MS are useful for studying noncovalent protein complexes. Collision induced dissociation (CID) is the most common MS/MS dissociation method. However, some protein complexes, including glycogen phosphorylase B kinase (PHB) and L-glutamate dehydrogenase (GDH) examined in this study, are resistant to dissociation by CID at the maximum collision energy available in the instrument. Surface induced dissociation (SID) was applied to dissociate the two refractory protein complexes. Different charge state precursor ions of the two complexes were examined by CID and SID. The PHB dimer was successfully dissociated to monomers and the GDH hexamer formed trimeric subcomplexes that are informative of its quaternary structure. The unfolding of the precursor and the percentages of the distinct products suggest that the dissociation pathways vary for different charge states. The precursors at lower charge states (+21 for PHB dimer and +27 for GDH hexamer) produce a higher percentage of folded fragments and dissociate more symmetrically than the precusors at higher charge states (+29 for PHB dimer and +39 for GDH hexamer). The precursors at lower charge state may be more native-like than the higher charge state because a higher percentage of folded fragments and a lower percentage of highly charged unfolded fragments are detected. The combination of SID and charge reduction is shown to be a powerful tool for quaternary structure analysis of refractory noncovalent protein complexes, as illustrated by the data for PHB dimer and GDH hexamer.

  1. Atomic description of the immune complex involved in heparin-induced thrombocytopenia

    DOE PAGESBeta

    Cai, Zheng; Yarovoi, Serge V.; Zhu, Zhiqiang; Rauova, Lubica; Hayes, Vincent; Lebedeva, Tatiana; Liu, Qun; Poncz, Mortimer; Arepally, Gowthami; Cines, Douglas B.; et al

    2015-09-22

    Heparin-induced thrombocytopenia (HIT) is an autoimmune thrombotic disorder caused by immune complexes containing platelet factor 4 (PF4), antibodies to PF4 and heparin or cellular glycosaminoglycans (GAGs). Here we solve the crystal structures of the: (1) PF4 tetramer/fondaparinux complex, (2) PF4 tetramer/KKO-Fab complex (a murine monoclonal HIT-like antibody) and (3) PF4 monomer/RTO-Fab complex (a non-HIT anti-PF4 monoclonal antibody). Fondaparinux binds to the ‘closed’ end of the PF4 tetramer and stabilizes its conformation. This interaction in turn stabilizes the epitope for KKO on the ‘open’ end of the tetramer. Fondaparinux and KKO thereby collaborate to ‘stabilize’ the ternary pathogenic immune complex. Bindingmore » of RTO to PF4 monomers prevents PF4 tetramerization and inhibits KKO and human HIT IgG-induced platelet activation and platelet aggregation in vitro, and thrombus progression in vivo. Lastly, the atomic structures provide a basis to develop new diagnostics and non-anticoagulant therapeutics for HIT.« less

  2. Atomic description of the immune complex involved in heparin-induced thrombocytopenia

    PubMed Central

    Cai, Zheng; Yarovoi, Serge V.; Zhu, Zhiqiang; Rauova, Lubica; Hayes, Vincent; Lebedeva, Tatiana; Liu, Qun; Poncz, Mortimer; Arepally, Gowthami; Cines, Douglas B.; Greene, Mark I.

    2015-01-01

    Heparin-induced thrombocytopenia (HIT) is an autoimmune thrombotic disorder caused by immune complexes containing platelet factor 4 (PF4), antibodies to PF4 and heparin or cellular glycosaminoglycans (GAGs). Here we solve the crystal structures of the: (1) PF4 tetramer/fondaparinux complex, (2) PF4 tetramer/KKO-Fab complex (a murine monoclonal HIT-like antibody) and (3) PF4 monomer/RTO-Fab complex (a non-HIT anti-PF4 monoclonal antibody). Fondaparinux binds to the ‘closed' end of the PF4 tetramer and stabilizes its conformation. This interaction in turn stabilizes the epitope for KKO on the ‘open' end of the tetramer. Fondaparinux and KKO thereby collaborate to ‘stabilize' the ternary pathogenic immune complex. Binding of RTO to PF4 monomers prevents PF4 tetramerization and inhibits KKO and human HIT IgG-induced platelet activation and platelet aggregation in vitro, and thrombus progression in vivo. The atomic structures provide a basis to develop new diagnostics and non-anticoagulant therapeutics for HIT. PMID:26391892

  3. Atomic description of the immune complex involved in heparin-induced thrombocytopenia

    SciTech Connect

    Cai, Zheng; Yarovoi, Serge V.; Zhu, Zhiqiang; Rauova, Lubica; Hayes, Vincent; Lebedeva, Tatiana; Liu, Qun; Poncz, Mortimer; Arepally, Gowthami; Cines, Douglas B.; Greene, Mark I.

    2015-09-22

    Heparin-induced thrombocytopenia (HIT) is an autoimmune thrombotic disorder caused by immune complexes containing platelet factor 4 (PF4), antibodies to PF4 and heparin or cellular glycosaminoglycans (GAGs). Here we solve the crystal structures of the: (1) PF4 tetramer/fondaparinux complex, (2) PF4 tetramer/KKO-Fab complex (a murine monoclonal HIT-like antibody) and (3) PF4 monomer/RTO-Fab complex (a non-HIT anti-PF4 monoclonal antibody). Fondaparinux binds to the ‘closed’ end of the PF4 tetramer and stabilizes its conformation. This interaction in turn stabilizes the epitope for KKO on the ‘open’ end of the tetramer. Fondaparinux and KKO thereby collaborate to ‘stabilize’ the ternary pathogenic immune complex. Binding of RTO to PF4 monomers prevents PF4 tetramerization and inhibits KKO and human HIT IgG-induced platelet activation and platelet aggregation in vitro, and thrombus progression in vivo. Lastly, the atomic structures provide a basis to develop new diagnostics and non-anticoagulant therapeutics for HIT.

  4. Atomic description of the immune complex involved in heparin-induced thrombocytopenia.

    PubMed

    Cai, Zheng; Yarovoi, Serge V; Zhu, Zhiqiang; Rauova, Lubica; Hayes, Vincent; Lebedeva, Tatiana; Liu, Qun; Poncz, Mortimer; Arepally, Gowthami; Cines, Douglas B; Greene, Mark I

    2015-01-01

    Heparin-induced thrombocytopenia (HIT) is an autoimmune thrombotic disorder caused by immune complexes containing platelet factor 4 (PF4), antibodies to PF4 and heparin or cellular glycosaminoglycans (GAGs). Here we solve the crystal structures of the: (1) PF4 tetramer/fondaparinux complex, (2) PF4 tetramer/KKO-Fab complex (a murine monoclonal HIT-like antibody) and (3) PF4 monomer/RTO-Fab complex (a non-HIT anti-PF4 monoclonal antibody). Fondaparinux binds to the 'closed' end of the PF4 tetramer and stabilizes its conformation. This interaction in turn stabilizes the epitope for KKO on the 'open' end of the tetramer. Fondaparinux and KKO thereby collaborate to 'stabilize' the ternary pathogenic immune complex. Binding of RTO to PF4 monomers prevents PF4 tetramerization and inhibits KKO and human HIT IgG-induced platelet activation and platelet aggregation in vitro, and thrombus progression in vivo. The atomic structures provide a basis to develop new diagnostics and non-anticoagulant therapeutics for HIT. PMID:26391892

  5. Induced circularly polarized luminescence arising from anion or protein binding to racemic emissive lanthanide complexes

    NASA Astrophysics Data System (ADS)

    Carr, Rachel; Puckrin, Robert; McMahon, Brian K.; Pal, Robert; Parker, David; Pålsson, Lars-Olof

    2014-06-01

    A circularly polarized luminescence (CPL) spectrometer has been built and used to study the binding interaction of lactate and four different proteins with racemic EuIII and TbIII complexes in aqueous solution. Lactate binding gives rise to strong induced CPL spectra, and the observed emission dissymmetry factors vary linearly with enantiomeric composition. Particularly strong induced TbIII CPL also characterizes the binding interaction of alpha-1-acid glycoprotein with a dissociation constant, Kd, of 2.5 μM.

  6. Photocytotoxic oxovanadium(IV) complexes showing light-induced DNA and protein cleavage activity.

    PubMed

    Sasmal, Pijus K; Saha, Sounik; Majumdar, Ritankar; Dighe, Rajan R; Chakravarty, Akhil R

    2010-02-01

    Oxovanadium(IV) complexes [VO(L)(B)]Cl(2) (1-3), where L is bis(2-benzimidazolylmethyl)amine and B is 1,10-phenanthroline (phen), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq) or dipyrido[3,2-a:2',3'-c]phenazine (dppz), have been prepared, characterized, and their photo-induced DNA and protein cleavage activity studied. The photocytotoxicity of complex 3 has been studied using adenocarcinoma A549 cells. The phen complex 1, structurally characterized by single-crystal X-ray crystallography, shows the presence of a vanadyl group in six-coordinate VON(5) coordination geometry. The ligands L and phen display tridentate and bidentate N-donor chelating binding modes, respectively. The complexes exhibit a d-d band near 740 nm in 15% DMF-Tris-HCl buffer (pH 7.2). The phen and dpq complexes display an irreversible cathodic cyclic voltammetric response near -0.8 V in 20% DMF-Tris-HCl buffer having 0.1 M KCl as supporting electrolyte. The dppz complex 3 exhibits a quasi-reversible voltammogram near -0.6 V (vs SCE) that is assignable to the V(IV)-V(III) couple. The complexes bind to calf thymus DNA giving binding constant values in the range of 6.6 x 10(4)-2.9 x 10(5) M(-1). The binding site size, thermal melting and viscosity binding data suggest DNA surface and/or groove binding nature of the complexes. The complexes show poor "chemical nuclease" activity in dark in the presence of 3-mercaptopropionic acid or hydrogen peroxide. The dpq and dppz complexes are efficient photocleavers of plasmid DNA in UV-A light of 365 nm via a mechanistic pathway that involves formation of both singlet oxygen and hydroxyl radicals. The complexes show significant photocleavage of DNA in near-IR light (>750 nm) via hydroxyl radical pathway. Among the three complexes, the dppz complex 3 shows significant BSA and lysozyme protein cleavage activity in UV-A light of 365 nm via hydroxyl radical pathway. The dppz complex 3 also exhibits photocytotoxicity in non-small cell lung carcinoma/human lung

  7. Crystal Structure of the Lactose Operon Repressor and Its Complexes with DNA and Inducer

    NASA Astrophysics Data System (ADS)

    Lewis, Mitchell; Chang, Geoffrey; Horton, Nancy C.; Kercher, Michele A.; Pace, Helen C.; Schumacher, Maria A.; Brennan, Richard G.; Lu, Ponzy

    1996-03-01

    The lac operon of Escherichia coli is the paradigm for gene regulation. Its key component is the lac repressor, a product of the lacI gene. The three-dimensional structures of the intact lac repressor, the lac repressor bound to the gratuitous inducer isopropyl-β-D-1-thiogalactoside (IPTG) and the lac repressor complexed with a 21-base pair symmetric operator DNA have been determined. These three structures show the conformation of the molecule in both the induced and repressed states and provide a framework for understanding a wealth of biochemical and genetic information. The DNA sequence of the lac operon has three lac repressor recognition sites in a stretch of 500 base pairs. The crystallographic structure of the complex with DNA suggests that the tetrameric repressor functions synergistically with catabolite gene activator protein (CAP) and participates in the quaternary formation of repression loops in which one tetrameric repressor interacts simultaneously with two sites on the genomic DNA.

  8. ACF chromatin remodeling complex mediates stress–induced depressive–like behavior

    PubMed Central

    Sun, HaoSheng; Damez–Werno, Diane M.; Scobie, Kimberly N.; Shao, Ning–Yi; Dias, Caroline; Rabkin, Jacqui; Koo, Ja Wook; Korb, Erica; Bagot, Rosemary C.; Ahn, Francisca H.; Cahill, Michael E.; Labonté, Benoit; Mouzon, Ezekiell; Heller, Elizabeth A.; Cates, Hannah; Golden, Sam A; Gleason, Kelly; Russo, Scott J; Andrews, Simon; Neve, Rachael; Kennedy, Pamela J.; Maze, Ian; Dietz, David M.; Allis, C. David; Turecki, Gustavo; Varga–Weisz, Patrick; Tamminga, Carol; Shen, Li; Nestler, Eric J.

    2015-01-01

    Improved treatment for major depressive disorder (MDD) remains elusive due to limited understanding of its underlying biological mechanisms. Stress–induced maladaptive transcriptional regulation within limbic neural circuits likely contributes to the development of MDD, possibly through epigenetic factors that regulate chromatin structure. We establish that persistent upregulation of the ACF ATP–dependent chromatin remodeling complex, occurring in the nucleus accumbens of stress–susceptible mice and depressed humans, is necessary for stress–induced depressive–like behaviors. Altered ACF binding after chronic stress is correlated with altered nucleosome positioning, particularly around the transcription start sites of affected genes. These alterations in ACF binding and nucleosome positioning are associated with repressed expression of genes implicated in susceptibility to stress. Together, we identify the ACF chromatin remodeling complex as a critical component in the development of susceptibility to depression and in regulating stress–related behaviors. PMID:26390241

  9. Successful treatment of pegaspargase-induced acute hepatotoxicity with vitamin B complex and L-carnitine

    PubMed Central

    Karur, Vinit; Herrington, Jon D.; Walker, Mary G.

    2016-01-01

    Pegaspargase is a chemotherapy drug used in the treatment of acute lymphoblastic leukemia (ALL). One of the adverse effects of pegaspargase is hepatotoxicity, which can rapidly lead to liver failure and death. We report a patient with ALL who developed pegaspargase-induced severe hepatotoxicity that was rescued by treatment with vitamin B complex and L-carnitine. Our patient had a quicker response than prior reported cases, suggesting this treatment might be a better regimen. PMID:26722167

  10. A mouse model of mitochondrial complex III dysfunction induced by myxothiazol

    SciTech Connect

    Davoudi, Mina; Kallijärvi, Jukka; Marjavaara, Sanna; Kotarsky, Heike; Hansson, Eva; Levéen, Per; Fellman, Vineta

    2014-04-18

    Highlights: • Reversible chemical inhibition of complex III in wild type mouse. • Myxothiazol causes decreased complex III activity in mouse liver. • The model is useful for therapeutic trials to improve mitochondrial function. - Abstract: Myxothiazol is a respiratory chain complex III (CIII) inhibitor that binds to the ubiquinol oxidation site Qo of CIII. It blocks electron transfer from ubiquinol to cytochrome b and thus inhibits CIII activity. It has been utilized as a tool in studies of respiratory chain function in in vitro and cell culture models. We developed a mouse model of biochemically induced and reversible CIII inhibition using myxothiazol. We administered myxothiazol intraperitoneally at a dose of 0.56 mg/kg to C57Bl/J6 mice every 24 h and assessed CIII activity, histology, lipid content, supercomplex formation, and gene expression in the livers of the mice. A reversible CIII activity decrease to 50% of control value occurred at 2 h post-injection. At 74 h only minor histological changes in the liver were found, supercomplex formation was preserved and no significant changes in the expression of genes indicating hepatotoxicity or inflammation were found. Thus, myxothiazol-induced CIII inhibition can be induced in mice for four days in a row without overt hepatotoxicity or lethality. This model could be utilized in further studies of respiratory chain function and pharmacological approaches to mitochondrial hepatopathies.

  11. Complexity of Multi-Dimensional Spontaneous EEG Decreases during Propofol Induced General Anaesthesia

    PubMed Central

    Schartner, Michael; Seth, Anil; Noirhomme, Quentin; Boly, Melanie; Bruno, Marie-Aurelie; Laureys, Steven; Barrett, Adam

    2015-01-01

    Emerging neural theories of consciousness suggest a correlation between a specific type of neural dynamical complexity and the level of consciousness: When awake and aware, causal interactions between brain regions are both integrated (all regions are to a certain extent connected) and differentiated (there is inhomogeneity and variety in the interactions). In support of this, recent work by Casali et al (2013) has shown that Lempel-Ziv complexity correlates strongly with conscious level, when computed on the EEG response to transcranial magnetic stimulation. Here we investigated complexity of spontaneous high-density EEG data during propofol-induced general anaesthesia. We consider three distinct measures: (i) Lempel-Ziv complexity, which is derived from how compressible the data are; (ii) amplitude coalition entropy, which measures the variability in the constitution of the set of active channels; and (iii) the novel synchrony coalition entropy (SCE), which measures the variability in the constitution of the set of synchronous channels. After some simulations on Kuramoto oscillator models which demonstrate that these measures capture distinct ‘flavours’ of complexity, we show that there is a robustly measurable decrease in the complexity of spontaneous EEG during general anaesthesia. PMID:26252378

  12. Insensitive dependence of delay-induced oscillation death on complex networks

    NASA Astrophysics Data System (ADS)

    Zou, Wei; Zheng, Xing; Zhan, Meng

    2011-06-01

    Oscillation death (also called amplitude death), a phenomenon of coupling induced stabilization of an unstable equilibrium, is studied for an arbitrary symmetric complex network with delay-coupled oscillators, and the critical conditions for its linear stability are explicitly obtained. All cases including one oscillator, a pair of oscillators, regular oscillator networks, and complex oscillator networks with delay feedback coupling, can be treated in a unified form. For an arbitrary symmetric network, we find that the corresponding smallest eigenvalue of the Laplacian λN (0 >λN ≥ -1) completely determines the death island, and as λN is located within the insensitive parameter region for nearly all complex networks, the death island keeps nearly the largest and does not sensitively depend on the complex network structures. This insensitivity effect has been tested for many typical complex networks including Watts-Strogatz (WS) and Newman-Watts (NW) small world networks, general scale-free (SF) networks, Erdos-Renyi (ER) random networks, geographical networks, and networks with community structures and is expected to be helpful for our understanding of dynamics on complex networks.

  13. Complexity of Multi-Dimensional Spontaneous EEG Decreases during Propofol Induced General Anaesthesia.

    PubMed

    Schartner, Michael; Seth, Anil; Noirhomme, Quentin; Boly, Melanie; Bruno, Marie-Aurelie; Laureys, Steven; Barrett, Adam

    2015-01-01

    Emerging neural theories of consciousness suggest a correlation between a specific type of neural dynamical complexity and the level of consciousness: When awake and aware, causal interactions between brain regions are both integrated (all regions are to a certain extent connected) and differentiated (there is inhomogeneity and variety in the interactions). In support of this, recent work by Casali et al (2013) has shown that Lempel-Ziv complexity correlates strongly with conscious level, when computed on the EEG response to transcranial magnetic stimulation. Here we investigated complexity of spontaneous high-density EEG data during propofol-induced general anaesthesia. We consider three distinct measures: (i) Lempel-Ziv complexity, which is derived from how compressible the data are; (ii) amplitude coalition entropy, which measures the variability in the constitution of the set of active channels; and (iii) the novel synchrony coalition entropy (SCE), which measures the variability in the constitution of the set of synchronous channels. After some simulations on Kuramoto oscillator models which demonstrate that these measures capture distinct 'flavours' of complexity, we show that there is a robustly measurable decrease in the complexity of spontaneous EEG during general anaesthesia. PMID:26252378

  14. Photo-induced reactions in the ion-molecule complex Mg+-OCNC2H5

    NASA Astrophysics Data System (ADS)

    Sun, Ju-Long; Liu, Haichuan; Han, Ke-Li; Yang, Shihe

    2003-06-01

    Ion-molecule complexes of magnesium cation with ethyl isocyanate were produced in a laser-ablation supersonic expansion nozzle source. Photo-induced reactions in the 1:1 complexes have been studied in the spectral range of 230-410 nm. Photodissociation mass spectrometry revealed the persistent product Mg+ from nonreactive quenching throughout the entire wavelength range. As for the reactive channels, the photoproducts, Mg+OCN and C2H5+, were produced only in the blue absorption band of the complex with low yields. The action spectrum of Mg+(OCNC2H5) consists of two pronounced peaks on the red and blue sides of the Mg+ 32P←32S atomic transition. The ground state geometry of Mg+-OCNC2H5 was fully optimized at B3LYP/6-31+G** level by using GAUSSIAN 98 package. The calculated absorption spectrum of the complex using the optimized structure of its ground state agrees well with the observed action spectrum. Photofragment branching fractions of the products are almost independent of the photolysis photon energy for the 3Px,y,z excitations. The very low branching ratio of reactive products to nonreactive fragment suggests that evaporation is the main relaxation pathway in the photo-induced reactions of Mg+(OCNC2H5).

  15. Use of laser induced photoacoustic spectroscopy (LIPAS) to determine equilibrium constants of cation-cation complexes

    SciTech Connect

    Hannink, N.J.; Hoffman, D.C.; Silva, R.J.; Russo, R.E.

    1993-12-31

    Laser Induced PhotoAcoustic Spectroscopy (LIPAS) is a relatively new, photothermal technique to examine solutions. Studies in the past have shown it to be more sensitive than conventional absorption spectroscopy, while, yielding the same information thus allowing lower concentrations to be used. This study is using LIPAS to examine solutions to determine the equilibrium constants of cation-cation complexes. It has been found that actinyl(V) cations form cation-cation complexes with a variety of cations, including actinyl(VI) cations. The radioactive nature of the actinide elements requires special handling techniques and also require limits be placed on the amount of material that can be used. The sensitivity of some oxidation states of the actinides to oxygen also presents a problem. Preliminary results will be presented for actinyl(V)-actinyl(VI) cation-cation complexes that were studied using a remote LIPAS system incorporating fiber optics for transmission of laser signals.

  16. Complex I and complex III inhibition specifically increase cytosolic hydrogen peroxide levels without inducing oxidative stress in HEK293 cells

    PubMed Central

    Forkink, Marleen; Basit, Farhan; Teixeira, José; Swarts, Herman G.; Koopman, Werner J.H.; Willems, Peter H.G.M.

    2015-01-01

    Inhibitor studies with isolated mitochondria demonstrated that complex I (CI) and III (CIII) of the electron transport chain (ETC) can act as relevant sources of mitochondrial reactive oxygen species (ROS). Here we studied ROS generation and oxidative stress induction during chronic (24 h) inhibition of CI and CIII using rotenone (ROT) and antimycin A (AA), respectively, in intact HEK293 cells. Both inhibitors stimulated oxidation of the ROS sensor hydroethidine (HEt) and increased mitochondrial NAD(P)H levels without major effects on cell viability. Integrated analysis of cells stably expressing cytosolic- or mitochondria-targeted variants of the reporter molecules HyPer (H2O2-sensitive and pH-sensitive) and SypHer (H2O2-insensitive and pH-sensitive), revealed that CI- and CIII inhibition increased cytosolic but not mitochondrial H2O2 levels. Total and mitochondria-specific lipid peroxidation was not increased in the inhibited cells as reported by the C11-BODIPY581/591 and MitoPerOx biosensors. Also expression of the superoxide-detoxifying enzymes CuZnSOD (cytosolic) and MnSOD (mitochondrial) was not affected. Oxyblot analysis revealed that protein carbonylation was not stimulated by CI and CIII inhibition. Our findings suggest that chronic inhibition of CI and CIII: (i) increases the levels of HEt-oxidizing ROS and (ii) specifically elevates cytosolic but not mitochondrial H2O2 levels, (iii) does not induce oxidative stress or substantial cell death. We conclude that the increased ROS levels are below the stress-inducing level and might play a role in redox signaling. PMID:26516986

  17. In vitro activation of rat neutrophils and alveolar macrophages with IgA and IgG immune complexes. Implications for immune complex-induced lung injury.

    PubMed Central

    Warren, J. S.; Kunkel, S. L.; Johnson, K. J.; Ward, P. A.

    1987-01-01

    In the rat, both IgG and IgA immune complexes induce oxygen radical mediated lung injury that is partially complement-dependent. In vivo studies have suggested that the chief sources of oxygen radicals in IgG and IgA immune complex-induced lung injury are neutrophils and tissue macrophages, respectively. The current studies have been designed to provide additional insights into these two models of tissue injury. Preformed monoclonal IgG and IgA immune complexes stimulated dose-dependent O2-. and H2O2 production by alveolar macrophages. In contrast, neutrophils exhibited O2-. production and lysosomal enzyme secretion in response to IgG immune complexes, but not in response to IgA complexes. There is evidence that C5a significantly amplifies these responses. Purified human C5a enhanced the O2-. responses of neutrophils activated with IgG immune complexes and alveolar macrophages activated with either IgG or IgA immune complexes. Addition of C5a alone to neutrophils or alveolar macrophages had no direct stimulatory effect as measured by O2-. production. The observation that O2-. responses of immune complex-activated alveolar macrophages can be significantly enhanced by the presence of C5a and that C5a can also enhance O-2. responses of IgG immune complex-stimulated neutrophils suggests a potential amplification mechanism through which complement may participate in both IgG and IgA immune complex-induced lung injury. The present data corroborate in vivo studies which suggest that IgG immune complex lung injury is primarily neutrophil-mediated, whereas IgA complex lung injury is predominantly macrophage-mediated. PMID:2827492

  18. Multi-therapeutic potential of autoantibodies induced by immune complexes trapped on follicular dendritic cells

    PubMed Central

    El Shikh, Mohey Eldin; Kmieciak, Maciej; Manjili, Masoud H; Szakal, Andras K; Pitzalis, Costantino; Tew, John G

    2013-01-01

    Induction of autoantibodies (autoAbs) targeting disease drivers / mediators is emerging as a potential immunotherapeutic strategy. Auto-immune complex (IC)-retaining follicular dendritic cells (FDCs) critically regulate pathogenic autoAb production in autoreactive germinal centers (GCs); however, their ability to induce potentially therapeutic autoAbs has not been explored. We hypothesized that deliberate display of clinically targeted antigens (Ags) in the form of ICs on FDC membranes induces target-specific autoreactive GCs and autoAbs that may be exploited therapeutically. To test our hypothesis, three therapeutically relevant Ags: TNF-α, HER2/neu and IgE, were investigated. Our results indicated that TNF-α-, HER2/neu- and IgE-specific autoAbs associated with strong GC reactions were induced by TNF-α-, HER2/neu- and IgE-IC retention on FDCs. Moreover, the induced anti-TNF-α autoAbs neutralized mouse and human TNF-α with half maximal Inhibitory Concentration (IC50) of 7.1 and 1.6 nM respectively. In addition, we demonstrated that FDC-induced Ab production could be non-specifically inhibited by the IgG-specific Endo-S that accessed the light zones of GCs and interfered with FDC-IC retention. In conclusion, the ability of FDCs to productively present autoAgs raises the potential for a novel immunotherapeutic platform targeting mediators of autoimmune disorders, allergic diseases, and Ab responsive cancers. PMID:23836278

  19. Consciousness and Complexity during Unresponsiveness Induced by Propofol, Xenon, and Ketamine.

    PubMed

    Sarasso, Simone; Boly, Melanie; Napolitani, Martino; Gosseries, Olivia; Charland-Verville, Vanessa; Casarotto, Silvia; Rosanova, Mario; Casali, Adenauer Girardi; Brichant, Jean-Francois; Boveroux, Pierre; Rex, Steffen; Tononi, Giulio; Laureys, Steven; Massimini, Marcello

    2015-12-01

    A common endpoint of general anesthetics is behavioral unresponsiveness, which is commonly associated with loss of consciousness. However, subjects can become disconnected from the environment while still having conscious experiences, as demonstrated by sleep states associated with dreaming. Among anesthetics, ketamine is remarkable in that it induces profound unresponsiveness, but subjects often report "ketamine dreams" upon emergence from anesthesia. Here, we aimed at assessing consciousness during anesthesia with propofol, xenon, and ketamine, independent of behavioral responsiveness. To do so, in 18 healthy volunteers, we measured the complexity of the cortical response to transcranial magnetic stimulation (TMS)--an approach that has proven helpful in assessing objectively the level of consciousness irrespective of sensory processing and motor responses. In addition, upon emergence from anesthesia, we collected reports about conscious experiences during unresponsiveness. Both frontal and parietal TMS elicited a low-amplitude electroencephalographic (EEG) slow wave corresponding to a local pattern of cortical activation with low complexity during propofol anesthesia, a high-amplitude EEG slow wave corresponding to a global, stereotypical pattern of cortical activation with low complexity during xenon anesthesia, and a wakefulness-like, complex spatiotemporal activation pattern during ketamine anesthesia. Crucially, participants reported no conscious experience after emergence from propofol and xenon anesthesia, whereas after ketamine they reported long, vivid dreams unrelated to the external environment. These results are relevant because they suggest that brain complexity may be sensitive to the presence of disconnected consciousness in subjects who are considered unconscious based on behavioral responses. PMID:26752078

  20. The TrxG Complex Mediates Cytokine Induced De Novo Enhancer Formation in Islets

    PubMed Central

    Hurley, Peter; Dhillon, Jasmine; Gill, Amol; Whiting, Cheryl

    2015-01-01

    To better understand how β-cells respond to proinflammatory cytokines we mapped the locations of histone 3 lysine 4 monomethylation (H3K4me1), a post-translational histone modification enriched at active and poised cis-regulatory regions, in IFNγ, Il-1β, and TNFα treated pancreatic islets. We identified 96,721 putative cis-regulatory loci, of which 3,590 were generated de novo, 3,204 had increased H3K4me1, and 5,354 had decreased H3K4me1 in IFNγ, Il-1β, and TNFα exposed islets. Roughly 10% of the de novo and increased regions were enriched for the repressive histone modification histone 3 lysine 27 trimethylation (H3K27me3) in untreated cells, and these were frequently associated with chemokine genes. We show that IFNγ, Il-1β, and TNFα exposure overcomes this repression and induces chemokine gene activation in as little as three hours, and that this expression persists for days in absence of continued IFNγ, Il-1β, and TNFα exposure. We implicate trithorax group (TrxG) complexes as likely players in the conversion of these repressed loci to an active state. To block the activity of these complexes, we suppressed Wdr5, a core component of the TrxG complexes, and used the H3K27me3 demethylase inhibitor GSK-J4. We show that GSK-J4 is particularly effective in blunting IFNγ, Il-1β, and TNFα-induced chemokine gene expression in β-cells; however, it induced significant islet-cell apoptosis and β-cell dysfunction. Wdr5 suppression also reduced IFNγ, Il-1β, and TNFα induced chemokine gene expression in β-cells without affecting islet-cell survival or β-cell function after 48hrs, but did begin to increase islet-cell apoptosis and β-cell dysfunction after four days of treatment. Taken together these data suggest that the TrxG complex is potentially a viable target for preventing cytokine induced chemokine gene expression in β-cells. PMID:26505193

  1. Mining-induced seismicity prediction in the Khibiny mines by complex of precursors

    NASA Astrophysics Data System (ADS)

    Zhuravleva, Olga; Fedotova, Iuliia

    2013-04-01

    Problem of mining-induced seismicity is important now for many world regions with an advanced mining industry, including the Khibiny massif region (Kola Peninsula). Studying of seismic activity in rock mass and prediction of rockbursts and mining-induced earthquakes for exploited deposits is carried out using complex assessment method. The following precursors are considered to be rock seismicity characteristics: decreasing fractal dimension, b-value, concentration, and average length of fractures These precursors are analyzed by complex assessment method developed. Influence of determinative factors is taken into consideration as well: presence of discontinuous disturbances, stope zone limits and edge of falls of the hanging wall rocks. Changing of the complex assessment is considered in space and time. It has been determined that there are increases of complex assessment values and seismically active zone size before a strong seismic event or events series. Timely detection of the focal source forming is an important stage of the prediction. The program MIEPS was developed to automate the calculations. By this program we can analyze the seismicity in both real-time and retrospectively. One of successful prediction by complex assessment is detection of main fault forming and occurrence of roofing failure in the United Kirovsky mine, "Apatit" JSC. A precursor was detected 3 days before seismic events group occurrence (105-107J). In this time a complex assessment value changed from 0.49 to 0.54 (transfer of stable seismic zone to increasing seismic zone), and a seismic active zone increased in 1.5 times within 24 hours. Factors determining the region's seismicity are high horizontal stresses in the rock mass, long-term exploited deposits and seasonal rock watering. They result to blocks movements on faults. The blasting of blasthole rings in this part of the rock mass (23.05.2012) triggered growing of the main fault, accompanied by seismic events (energy < 2×107J

  2. Microbial metabolic networks in a complex electrogenic biofilm recovered from a stimulus-induced metatranscriptomics approach

    PubMed Central

    Ishii, Shun’ichi; Suzuki, Shino; Tenney, Aaron; Norden-Krichmar, Trina M.; Nealson, Kenneth H.; Bretschger, Orianna

    2015-01-01

    Microorganisms almost always exist as mixed communities in nature. While the significance of microbial community activities is well appreciated, a thorough understanding about how microbial communities respond to environmental perturbations has not yet been achieved. Here we have used a combination of metagenomic, genome binning, and stimulus-induced metatranscriptomic approaches to estimate the metabolic network and stimuli-induced metabolic switches existing in a complex microbial biofilm that was producing electrical current via extracellular electron transfer (EET) to a solid electrode surface. Two stimuli were employed: to increase EET and to stop EET. An analysis of cell activity marker genes after stimuli exposure revealed that only two strains within eleven binned genomes had strong transcriptional responses to increased EET rates, with one responding positively and the other responding negatively. Potential metabolic switches between eleven dominant members were mainly observed for acetate, hydrogen, and ethanol metabolisms. These results have enabled the estimation of a multi-species metabolic network and the associated short-term responses to EET stimuli that induce changes to metabolic flow and cooperative or competitive microbial interactions. This systematic meta-omics approach represents a next step towards understanding complex microbial roles within a community and how community members respond to specific environmental stimuli. PMID:26443302

  3. Microbial metabolic networks in a complex electrogenic biofilm recovered from a stimulus-induced metatranscriptomics approach.

    PubMed

    Ishii, Shun'ichi; Suzuki, Shino; Tenney, Aaron; Norden-Krichmar, Trina M; Nealson, Kenneth H; Bretschger, Orianna

    2015-01-01

    Microorganisms almost always exist as mixed communities in nature. While the significance of microbial community activities is well appreciated, a thorough understanding about how microbial communities respond to environmental perturbations has not yet been achieved. Here we have used a combination of metagenomic, genome binning, and stimulus-induced metatranscriptomic approaches to estimate the metabolic network and stimuli-induced metabolic switches existing in a complex microbial biofilm that was producing electrical current via extracellular electron transfer (EET) to a solid electrode surface. Two stimuli were employed: to increase EET and to stop EET. An analysis of cell activity marker genes after stimuli exposure revealed that only two strains within eleven binned genomes had strong transcriptional responses to increased EET rates, with one responding positively and the other responding negatively. Potential metabolic switches between eleven dominant members were mainly observed for acetate, hydrogen, and ethanol metabolisms. These results have enabled the estimation of a multi-species metabolic network and the associated short-term responses to EET stimuli that induce changes to metabolic flow and cooperative or competitive microbial interactions. This systematic meta-omics approach represents a next step towards understanding complex microbial roles within a community and how community members respond to specific environmental stimuli. PMID:26443302

  4. Brefeldin A-induced ADP-ribosylation in the structure and function of the Golgi complex.

    PubMed

    Colanzi, A; Mironov, A; Weigert, R; Limina, C; Flati, S; Cericola, C; Di Tullio, G; Di Girolamo, M; Corda, D; De Matteis, M A; Luini, A

    1997-01-01

    Brefeldin A (BFA) is a fungal metabolite that exerts generally inhibitory actions on membrane transport and induces the disappearance of the Golgi complex. Previously we have shown that BFA stimulates the ADP-ribosylation of two cytosolic proteins of 38 and 50 KD. The BFA-binding components mediating the BFA-sensitive ADP-ribosylation (BAR) and the effect of BFA on ARF binding to Golgi membranes have similar specificities and affinities for BFA and its analogues, suggesting that BAR may have a role in the cellular effects of BFA. To investigate this we used the approach to impair BAR activity by the use of BAR inhibitors. A series of BAR inhibitors was developed and their effects were studied in RBL cells treated with BFA. In addition to the common ADP-ribosylation inhibitors (nicotinamide and aminobenzamide), compounds belonging to the cumarin (novobiocin, cumermycin, dicumarol) class were active BAR inhibitors. All BAR inhibitors were able to prevent the BFA-induced redistribution of a Golgi marker (Helix pomatia lectin) into the endoplasmic reticulum, as assessed in immunofluorescence experiments. At the ultrastructural level, BAR inhibitors prevented the tubular-vesicular transformation of the Golgi complex caused by BFA. The potencies of these compounds in preventing the BFA effects on the Golgi complex were similar to those at which they inhibited BAR. Altogether these data support the hypothesis that BAR mediates at least some of the effects of BFA on the Golgi structure and function. PMID:9193673

  5. Subcritical Water Induced Complexation of Soy Protein and Rutin: Improved Interfacial Properties and Emulsion Stability.

    PubMed

    Chen, Xiao-Wei; Wang, Jin-Mei; Yang, Xiao-Quan; Qi, Jun-Ru; Hou, Jun-Jie

    2016-09-01

    Rutin is a common dietary flavonoid with important antioxidant and pharmacological activities. However, its application in the food industry is limited mainly because of its poor water solubility. The subcritical water (SW) treatment provides an efficient technique to solubilize and achieve the enrichment of rutin in soy protein isolate (SPI) by inducing their complexation. The physicochemical, interfacial, and emulsifying properties of the complex were investigated and compared to the mixtures. SW treatment had much enhanced rutin-combined capacity of SPI than that of conventional method, ascribing to the well-contacted for higher water solubility of rutin with stronger collision-induced hydrophobic interactions. Compared to the mixtures of rutin with proteins, the complex exhibited an excellent surface activity and improved the physical and oxidative stability of its stabilized emulsions. This improving effect could be attributed to the targeted accumulation of rutin at the oil-water interface accompanied by the adsorption of SPI resulting in the thicker interfacial layer, as evidenced by higher interfacial protein and rutin concentrations. This study provides a novel strategy for the design and enrichment of nanovehicle providing water-insoluble hydrophobic polyphenols for interfacial delivery in food emulsified systems. PMID:27467966

  6. Neisseria gonorrhoeae induced disruption of cell junction complexes in epithelial cells of the human genital tract.

    PubMed

    Rodríguez-Tirado, Carolina; Maisey, Kevin; Rodríguez, Felipe E; Reyes-Cerpa, Sebastián; Reyes-López, Felipe E; Imarai, Mónica

    2012-03-01

    Pathogenic microorganisms, such as Neisseria gonorrhoeae, have developed mechanisms to alter epithelial barriers in order to reach subepithelial tissues for host colonization. The aim of this study was to examine the effects of gonococci on cell junction complexes of genital epithelial cells of women. Polarized Ishikawa cells, a cell line derived from endometrial epithelium, were used for experimental infection. Infected cells displayed a spindle-like shape with an irregular distribution, indicating potential alteration of cell-cell contacts. Accordingly, analysis by confocal microscopy and cellular fractionation revealed that gonococci induced redistribution of the adherens junction proteins E-cadherin and its adapter protein β-catenin from the membrane to a cytoplasmic pool, with no significant differences in protein levels. In contrast, gonococcal infection did not induce modification of either expression or distribution of the tight junction proteins Occludin and ZO-1. Similar results were observed for Fallopian tube epithelia. Interestingly, infected Ishikawa cells also showed an altered pattern of actin cytoskeleton, observed in the form of stress fibers across the cytoplasm, which in turn matched a strong alteration on the expression of fibronectin, an adhesive glycoprotein component of extracellular matrix. Interestingly, using western blotting, activation of the ERK pathway was detected after gonococcal infection while p38 pathway was not activated. All effects were pili and Opa independent. Altogether, results indicated that gonococcus, as a mechanism of pathogenesis, induced disruption of junction complexes with early detaching of E-cadherin and β-catenin from the adherens junction complex, followed by a redistribution and reorganization of actin cytoskeleton and fibronectin within the extracellular matrix. PMID:22146107

  7. Nitrosative modifications of the Ca2+ release complex and actin underlie arthritis-induced muscle weakness

    PubMed Central

    Yamada, Takashi; Fedotovskaya, Olga; Cheng, Arthur J; Cornachione, Anabelle S; Minozzo, Fabio C; Aulin, Cecilia; Fridén, Cecilia; Turesson, Carl; Andersson, Daniel C; Glenmark, Birgitta; Lundberg, Ingrid E; Rassier, Dilson E; Westerblad, Håkan; Lanner, Johanna T

    2015-01-01

    Objective Skeletal muscle weakness is a prominent clinical feature in patients with rheumatoid arthritis (RA), but the underlying mechanism(s) is unknown. Here we investigate the mechanisms behind arthritis-induced skeletal muscle weakness with special focus on the role of nitrosative stress on intracellular Ca2+ handling and specific force production. Methods Nitric oxide synthase (NOS) expression, degree of nitrosative stress and composition of the major intracellular Ca2+ release channel (ryanodine receptor 1, RyR1) complex were measured in muscle. Changes in cytosolic free Ca2+ concentration ([Ca2+]i) and force production were assessed in single-muscle fibres and isolated myofibrils using atomic force cantilevers. Results The total neuronal NOS (nNOS) levels were increased in muscles both from collagen-induced arthritis (CIA) mice and patients with RA. The nNOS associated with RyR1 was increased and accompanied by increased [Ca2+]i during contractions of muscles from CIA mice. A marker of peroxynitrite-derived nitrosative stress (3-nitrotyrosine, 3-NT) was increased on the RyR1 complex and on actin of muscles from CIA mice. Despite increased [Ca2+]i, individual CIA muscle fibres were weaker than in healthy controls, that is, force per cross-sectional area was decreased. Furthermore, force and kinetics were impaired in CIA myofibrils, hence actin and myosin showed decreased ability to interact, which could be a result of increased 3-NT content on actin. Conclusions Arthritis-induced muscle weakness is linked to nitrosative modifications of the RyR1 protein complex and actin, which are driven by increased nNOS associated with RyR1 and progressively increasing Ca2+ activation. PMID:24854355

  8. SWI/SNF complex prevents lineage reversion and induces temporal patterning in neural stem cells.

    PubMed

    Eroglu, Elif; Burkard, Thomas R; Jiang, Yanrui; Saini, Nidhi; Homem, Catarina C F; Reichert, Heinrich; Knoblich, Juergen A

    2014-03-13

    Members of the SWI/SNF chromatin-remodeling complex are among the most frequently mutated genes in human cancer, but how they suppress tumorigenesis is currently unclear. Here, we use Drosophila neuroblasts to demonstrate that the SWI/SNF component Osa (ARID1) prevents tumorigenesis by ensuring correct lineage progression in stem cell lineages. We show that Osa induces a transcriptional program in the transit-amplifying population that initiates temporal patterning, limits self-renewal, and prevents dedifferentiation. We identify the Prdm protein Hamlet as a key component of this program. Hamlet is directly induced by Osa and regulates the progression of progenitors through distinct transcriptional states to limit the number of transit-amplifying divisions. Our data provide a mechanistic explanation for the widespread tumor suppressor activity of SWI/SNF. Because the Hamlet homologs Evi1 and Prdm16 are frequently mutated in cancer, this mechanism could well be conserved in human stem cell lineages. PAPERCLIP: PMID:24630726

  9. Heat-induced formation of myosin oligomer-soluble filament complex in high-salt solution.

    PubMed

    Shimada, Masato; Takai, Eisuke; Ejima, Daisuke; Arakawa, Tsutomu; Shiraki, Kentaro

    2015-02-01

    Heat-induced aggregation of myosin into an elastic gel plays an important role in the water-holding capacity and texture of meat products. Here, we investigated thermal aggregation of porcine myosin in high-salt solution over a wide temperature range by dynamic light scattering experiments. The myosin samples were readily dissolved in 1.0 M NaCl at 25 °C followed by dilution into various salt concentrations. The diluted solutions consistently contained both myosin monomers and soluble filaments. The filament size decreased with increasing salt concentration and temperature. High temperatures above Tm led to at least partial dissociation of soluble filaments and thermal unfolding, resulting in the formation of soluble oligomers and binding to the persistently present soluble filaments. Such a complex formation between the oligomers and filaments has never been observed. Our results provide new insight into the heat-induced myosin gelation in high-salt solution. PMID:25445683

  10. Retrograde dilation of a complex radiation-induced esophageal stricture through percutaneous gastrostomy.

    PubMed

    Eminler, A T; Uslan, M I; Köksal, A Ş; Guven, M; Parlak, E

    2015-06-01

    Upper esophageal strictures occur in approximately 3-4% of patients who receive radiotherapy for head and neck cancers. The standart initial treatment is dilation by using bougie or through-the-scope balloon dilators. Endoscopic treatment requires the passage of a guidewire through the stricture which cannot be accomplished in some of the patients with complex strictures. Retrograde dilation of esophageal strictures through a mature percutaneous gastrostomy tract have been reported in a limited number of cases and small case series up to date and can be considered as a rescue treatment before considering surgery in such patients. Herein we report retrograde dilatation of a radiation-induced complex esophageal stricture through the percutaneous gastrostomy tract in a patient with operated larynx cancer. PMID:26151697

  11. Defect-impurity complex induced long-range ferromagnetism in GaN nanowires

    NASA Astrophysics Data System (ADS)

    Assa Aravindh, S.; Roqan, Iman S.

    2015-12-01

    Present work investigates the structural, electronic and magnetic properties of Gd doped wurtzite GaN nanowires (NWs) oriented along the [0001] direction in presence of intrinsic defects by employing the GGA + U approximation. We find that Ga vacancy (VGa) exhibits lower formation energy compared to N vacancy. Further stabilization of point defects occurs due to the presence of Gd. The strength of ferromagnetism (FM) increases by additional positive charge induced by the VGa. Electronic structure analysis shows that VGa introduces defect levels in the band gap leading to ferromagnetic coupling due to the hybridization of the p states of the Ga and N atoms with the Gd d and f states. Ferromagnetic exchange coupling energy of 76.4 meV is obtained in presence of Gd-VGa complex; hence, the FM is largely determined by the cation vacancy-rare earth complex defects in GaN NWs.

  12. Molecular Components of the Sporothrix schenckii Complex that Induce Immune Response.

    PubMed

    Alba-Fierro, Carlos A; Pérez-Torres, Armando; Toriello, Conchita; Romo-Lozano, Yolanda; López-Romero, Everardo; Ruiz-Baca, Estela

    2016-08-01

    Sporotrichosis is a fungal disease caused by the Sporothrix schenckii complex that includes species such as S. brasiliensis, S. schenckii sensu stricto, S. globosa, S. luriei, S. mexicana, and S. pallida, which exhibit different potentially antigenic molecular components. The immune response of susceptible hosts to control infection and disease caused by these fungi has been little studied. Besides, the fungus-host interaction induces the activation of different types of immune response. This mini-review analyzes and discusses existing reports on the identification and functional characterization of molecules from species of the S. schenckii complex with clinical relevance, and the mechanisms that mediate the type and magnitude of the immune response in experimental models in vivo and in vitro. This knowledge is expected to contribute to the development of protective and therapeutic strategies against sporotrichosis and other mycoses. PMID:27117164

  13. Touch induces ATP release in Arabidopsis roots that is modulated by the heterotrimeric G protein complex

    PubMed Central

    Weerasinghe, Ravisha R.; Swanson, Sarah J.; Okada, Seiko F.; Garrett, Michele B.; Kim, Sung-Yong; Stacey, Gary; Boucher, Richard C.; Gilroy, Simon; Jones, Alan M.

    2009-01-01

    Amongst the many stimuli orienting the growth of plant roots, of critical importance are the touch signals generated as roots explore the mechanically complex soil environment. However, the molecular mechanisms behind these sensory events remain poorly defined. We report an impaired obstacle-avoiding response of roots in Arabidopsis lacking a heterotrimeric G protein. Obstacle avoidance may utilize a touch-induced release of ATP to the extracellular space. While sequential touch stimulation revealed a strong refractory period for ATP release in response to mechanostimulation in wild-type plants, the refractory period in mutants was attenuated, resulting in extracellular ATP accumulation. We propose that ATP acts as an extracellular signal released by mechanostimulation and that the G-protein complex is needed for fine-tuning this response. PMID:19596005

  14. Propagating self-sustained annealing of radiation-induced interstitial complexes

    NASA Astrophysics Data System (ADS)

    Bokov, P. M.; Selyshchev, P. A.

    2016-02-01

    A propagating self-sustained annealing of radiation induced defects as a result of thermal-concentration instability is studied. The defects that are considered in the model are complexes. Each of them consists of one atom of impunity and of one interstitial atom. Crystal with defects has extra energy which is transformed into heat during defect annealing. Simulation of the auto-wave of annealing has been performed. The front and the speed of the auto-wave have been obtained. It is shown that annealing occurs in a narrow region of time and space. There are two kinds of such annealing behaviour. In the first case the speed of the auto-wave oscillates near its constant mean value and the front of temperature oscillates in a complex way. In the second case the speed of propagation is constant and fronts of temperature and concentration look like sigmoid functions.

  15. Visible-Light-Induced Morphological Changes of Giant Vesicles by Photoisomerization of a Ruthenium Aqua Complex.

    PubMed

    Hirahara, Masanari; Tsukamoto, Akira; Goto, Hiroki; Tada, Shigeru; Yagi, Masayuki; Umemura, Yasushi

    2016-02-18

    Visible- and red-light responsive vesicles were prepared by incorporating a ruthenium aqua complex having two alkyl chains on tridentate and asymmetrical bidentate ligands (proximal-2: [Ru(C10 tpy)(C10 pyqu)OH2 ](2+) , C10 tpy=4'-decyloxy-2,2';6',2"-terpyridine, C10 pyqu=2-[2'-(6'-decyloxy)-pyridyl]quinoline). The ruthenium complex of proximal-2 with closed alkyl chain geometry and a cylinder-like molecular shape exhibited photoisomerization to distal-2 with an open alkyl chain geometry and a cone-like shape, both in an aqueous solution and in vesicle dispersions. We observed that light irradiation of giant vesicles containing proximal-2 induced diverse morphological changes. PMID:26711139

  16. Characterization of lead induced metal-phytochelatin complexes in Chlamydomonas reinhardtii.

    PubMed

    Scheidegger, Christian; Sigg, Laura; Behra, Renata

    2011-11-01

    Accumulation of Pb and induction of phytochelatin synthesis were observed in Chlamydomonas reinhardtii upon Pb(II) exposure. Our aim was to examine whether Pb(II) is bound by phytochelatins (PCs) in C. reinhardtii and to examine formed complexes for their stoichiometry and composition. Metal-phytochelatin (Me-PC) complexes induced by Pb were isolated by size-exclusion chromatography in 13 collected fractions, which were analyzed for their PC and metal content by high-performance liquid chromatography and inductively coupled plasma mass spectrometry. A recovery of more than 90% of Pb from standard Pb-PC₂ complexes within the total volume of the size-exclusion column indicated the adequacy of the method for Pb-PC(n) complex separation and characterization. Phytochelatins were detected mainly in a molecular weight ranging from 1,000 to 5,300 daltons (Da), indicating the formation of complexes with various stoichiometries. Approximately 72% of total PC₂ eluted in the range from 1,000 to 1,600 Da, and 80% of total PC₃ eluted in the molecular weight range from 1,600 to 2,300 Da. The distribution of Cu, Zn, and Pb showed that more than 70% of these metals were associated with the high-molecular-weight fractions. Copper, zinc, and lead were also observed in PC-containing fractions, suggesting the formation of various Me-PC complexes. The results of the present study indicate that the role of PCs in Pb detoxification is minor, because only 13% of total Pb was associated with PCs. PMID:21898554

  17. Rabies virus phosphoprotein interacts with mitochondrial Complex I and induces mitochondrial dysfunction and oxidative stress.

    PubMed

    Kammouni, Wafa; Wood, Heidi; Saleh, Ali; Appolinario, Camila M; Fernyhough, Paul; Jackson, Alan C

    2015-08-01

    Our previous studies in an experimental model of rabies showed neuronal process degeneration in association with severe clinical disease. Cultured adult rodent dorsal root ganglion neurons infected with challenge virus standard (CVS)-11 strain of rabies virus (RABV) showed axonal swellings and reduced axonal growth with evidence of oxidative stress. We have shown that CVS infection alters a variety of mitochondrial parameters and increases reactive oxygen species (ROS) production and mitochondrial Complex I activity vs. mock infection. We have hypothesized that a RABV protein targets mitochondria and triggers dysfunction. Mitochondrial extracts of mouse neuroblastoma cells were analyzed with a proteomics approach. We have identified peptides belonging to the RABV nucleocapsid protein (N), phosphoprotein (P), and glycoprotein (G), and our data indicate that the extract was most highly enriched with P. P was also detected by immunoblotting in RABV-infected purified mitochondrial extracts and also in Complex I immunoprecipitates from the extracts but not in mock-infected extracts. A plasmid expressing P in cells increased Complex I activity and increased ROS generation, whereas expression of other RABV proteins did not. We have analyzed recombinant plasmids encoding various P gene segments. Expression of a peptide from amino acid 139-172 increased Complex I activity and ROS generation similar to expression of the entire P protein, whereas peptides that did not contain this region did not increase Complex I activity or induce ROS generation. These results indicate that a region of the RABV P interacts with Complex I in mitochondria causing mitochondrial dysfunction, increased generation of ROS, and oxidative stress. PMID:25698500

  18. STAGE-SPECIFIC DAMAGE TO SYNAPTONEMAL COMPLEXES AND METAPHASE CHROMOSOME INDUCED BY X RAYS IN MALE MOUSE GERM CELLS

    EPA Science Inventory

    Synaptonemal complexes (SCs) reveal mutagen-induced effects in germ cell meiotic chromosomes. his study was aimed at characterizing relationships between SC and metaphase I chromosome damage following radiation exposure at various stages of spermatogenesis. Male mice were irradia...

  19. Homochiral mononuclear Dy-Schiff base complexes showing field-induced double magnetic relaxation processes.

    PubMed

    Ren, Min; Xu, Zhong-Li; Wang, Ting-Ting; Bao, Song-Song; Zheng, Ze-Hua; Zhang, Zai-Chao; Zheng, Li-Min

    2016-01-14

    A pair of enantiopure mononuclear dysprosium/salen-type complexes (Et3NH)[Dy((R,R)/(S,S)-3-NO2salcy)2] (/), where 3-NO2salcyH2 represents N,N'-(1,2-cyclohexanediylethylene)bis(3-nitrosalicylideneiminato), are reported. The enantiomer contains two crystallographically independent dysprosium(iii) ions, each chelated by two enantiopure 3-NO2salcy(2-) ligands forming a [DyN4O4] core. Detailed magnetic studies on compound reveal a field-induced dual magnetic relaxation behavior, originating from single ion anisotropy and intermolecular interactions, respectively. PMID:26621766

  20. Efficient Charge Storage in Dual-Redox Electrochemical Capacitors through Reversible Counterion-Induced Solid Complexation.

    PubMed

    Evanko, Brian; Yoo, Seung Joon; Chun, Sang-Eun; Wang, Xingfeng; Ji, Xiulei; Boettcher, Shannon W; Stucky, Galen D

    2016-08-01

    The performance of redox-enhanced electrochemical capacitors (redox ECs) is substantially improved when oxidized catholyte (bromide) and reduced anolyte (viologen) are retained within the porous electrodes through reversible counterion-induced solid complexation. Investigation of the mechanism illustrates design principles and identifies pentyl viologen/bromide (PV/Br) as a new high-performance electrolyte. The symmetric PV/Br redox EC produces a specific energy of 48.5 W·h/kgdry at 0.5 A/gdry (0.44 kW/kgdry) with 99.7% Coulombic efficiency, maintains stability over 10 000 cycles, and functions identically when operated with reversed polarity. PMID:27442447

  1. Metal-induced gap states in ferroelectric capacitors and its relationship with complex band structures

    NASA Astrophysics Data System (ADS)

    Junquera, Javier; Aguado-Puente, Pablo

    2013-03-01

    At metal-isulator interfaces, the metallic wave functions with an energy eigenvalue within the band gap decay exponentially inside the dielectric (metal-induced gap states, MIGS). These MIGS can be actually regarded as Bloch functions with an associated complex wave vector. Usually only real values of the wave vectors are discussed in text books, since infinite periodicity is assumed and, in that situation, wave functions growing exponentially in any direction would not be physically valid. However, localized wave functions with an exponential decay are indeed perfectly valid solution of the Schrodinger equation in the presence of defects, surfaces or interfaces. For this reason, properties of MIGS have been typically discussed in terms of the complex band structure of bulk materials. The probable dependence on the interface particulars has been rarely taken into account explicitly due to the difficulties to include them into the model or simulations. We aim to characterize from first-principles simulations the MIGS in realistic ferroelectric capacitors and their connection with the complex band structure of the ferroelectric material. We emphasize the influence of the real interface beyond the complex band structure of bulk materials. Financial support provided by MICINN Grant FIS2009-12721-C04-02, and by the European Union Grant No. CP-FP 228989-2 ``OxIDes''. Computer resources provided by the RES.

  2. Delivery of fullerene-containing complexes via microgel swelling and shear-induced release.

    PubMed

    Tarabukina, Elena; Zoolshoev, Zoolsho; Melenevskaya, Elena; Budtova, Tatiana

    2010-01-15

    The absorption and release of poly(vinylpyrrolidone)-fullerene C60 complexes (PVP/C60) from a model microgel is studied. A dry microgel based on a chemically cross-linked sodium polyacrylate was swollen in the aqueous solutions of complexes which were afterwards released under shear stress. First, gel swelling degree in static conditions in the excess of PVP/C60 solutions was studied: the degree of swelling decreases with the increase in PVP/C60 concentration. While pure PVP is homogeneously distributed between the gel and the surrounding solution, a slight concentration of complexes outside the gel was recorded. It was attributed to PVP/C60 hydrophobicity leading to the decrease in the thermodynamic quality of fullerene-containing solution being gel solvent. The release of PVP/C60 solutions induced by shear was studied with counter-rotating rheo-optical technique and compared with PVP solution release under the same conditions. The amount of solution released depends on polymer concentration and shear strain. Contrary to pure PVP solutions in which rate of release decreases with the increase in polymer concentration, PVP/C60 complexes are released faster when fullerene concentration inside the gel is higher. PMID:19766708

  3. Hedgehog induces formation of PKA-Smoothened complexes to promote Smoothened phosphorylation and pathway activation

    PubMed Central

    Li, Shuang; Ma, Guoqiang; Wang, Bing; Jiang, Jin

    2015-01-01

    Hedgehog (Hh) is a secreted glycoprotein that binds its receptor Patched to activate the G protein-coupled receptor-like protein Smoothened (Smo). In Drosophila, protein kinase A (PKA) phosphorylates and activates Smo in cells stimulated with Hh. In unstimulated cells, PKA phosphorylates and inhibits the transcription factor Cubitus interruptus (Ci). Here, we found that in cells exposed to Hh, the catalytic subunit of PKA (PKAc) bound to the juxtamembrane region of the C terminus of Smo. PKA-mediated phosphorylation of Smo further enhanced its association with PKAc to form stable kinase-substrate complexes that promoted the PKA-mediated trans-phosphorylation of Smo dimers. We identified multiple basic residues in the C-terminus of Smo that were required for interaction with PKAc, Smo phosphorylation, and Hh pathway activation. Hh induced a switch from the association of PKAc with a cytosolic complex of Ci and the kinesin-like protein Costal2 (Cos2) to a membrane-bound Smo-Cos2 complex. Thus, our study uncovers a previously uncharacterized mechanism for regulation of PKA activity and demonstrates that the signal-regulated formation of kinase-substrate complexes plays a central role in Hh signal transduction. PMID:24985345

  4. Impaired retrograde transport by the Dynein/Dynactin complex contributes to Tau-induced toxicity.

    PubMed

    Butzlaff, Malte; Hannan, Shabab B; Karsten, Peter; Lenz, Sarah; Ng, Josephine; Voßfeldt, Hannes; Prüßing, Katja; Pflanz, Ralf; Schulz, Jörg B; Rasse, Tobias; Voigt, Aaron

    2015-07-01

    The gene mapt codes for the microtubule-associated protein Tau. The R406W amino acid substitution in Tau is associated with frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17) characterized by Tau-positive filamentous inclusions. These filamentous Tau inclusions are present in a group of neurodegenerative diseases known as tauopathies, including Alzheimer's disease (AD). To gain more insights into the pathomechanism of tauopathies, we performed an RNAi-based large-scale screen in Drosophila melanogaster to identify genetic modifiers of Tau[R406W]-induced toxicity. A collection of RNAi lines, putatively silencing more than 7000 genes, was screened for the ability to modify Tau[R406W]-induced toxicity in vivo. This collection covered more than 50% of all protein coding fly genes and more than 90% of all fly genes known to have a human ortholog. Hereby, we identified 62 genes that, when silenced by RNAi, modified Tau-induced toxicity specifically. Among these 62 modifiers were three subunits of the Dynein/Dynactin complex. Analysis on segmental nerves of fly larvae showed that pan neural Tau[R406W] expression and concomitant silencing of Dynein/Dynactin complex members synergistically caused strong pathological changes within the axonal compartment, but only minor changes at synapses. At the larval stage, these alterations did not cause locomotion deficits, but became evident in adult flies. Our data suggest that Tau-induced detrimental effects most likely originate from axonal rather than synaptic dysfunction and that impaired retrograde transport intensifies detrimental effects of Tau in axons. In conclusion, our findings contribute to the elucidation of disease mechanisms in tauopathies like FTDP-17 or AD. PMID:25794683

  5. Mechanisms of cell death pathway activation following drug-induced inhibition of mitochondrial complex I

    PubMed Central

    Imaizumi, Naoki; Kwang Lee, Kang; Zhang, Carmen; Boelsterli, Urs A.

    2015-01-01

    Respiratory complex I inhibition by drugs and other chemicals has been implicated as a frequent mode of mitochondria-mediated cell injury. However, the exact mechanisms leading to the activation of cell death pathways are incompletely understood. This study was designed to explore the relative contributions to cell injury of three distinct consequences of complex I inhibition, i.e., impairment of ATP biosynthesis, increased formation of superoxide and, hence, peroxynitrite, and inhibition of the mitochondrial protein deacetylase, Sirt3, due to imbalance of the NADH/NAD+ ratio. We used the antiviral drug efavirenz (EFV) to model drug-induced complex I inhibition. Exposure of cultured mouse hepatocytes to EFV resulted in a rapid onset of cell injury, featuring a no-effect level at 30 µM EFV and submaximal effects at 50 µM EFV. EFV caused a concentration-dependent decrease in cellular ATP levels. Furthermore, EFV resulted in increased formation of peroxynitrite and oxidation of mitochondrial protein thiols, including cyclophilin D (CypD). This was prevented by the superoxide scavenger, Fe-TCP, or the peroxynitrite decomposition catalyst, Fe-TMPyP. Both ferroporphyrins completely protected from EFV-induced cell injury, suggesting that peroxynitrite contributed to the cell injury. Finally, EFV increased the NADH/NAD+ ratio, inhibited Sirt3 activity, and led to hyperacetylated lysine residues, including those in CypD. However, hepatocytes isolated from Sirt3-null mice were protected against 40 µM EFV as compared to their wild-type controls. In conclusion, these data are compatible with the concept that chemical inhibition of complex I activates multiple pathways leading to cell injury; among these, peroxynitrite formation may be the most critical. PMID:25625582

  6. Crystal structure of the lactose operon repressor and its complexes with DNA and inducer

    SciTech Connect

    Lewis, M.; Chang, G.; Horton, N.C.

    1996-03-01

    The lac operon of Escherichia coli is the paradigm for gene regulation. Its key component is the lac repressor a product of the lacl gene. The three-dimensional structures of the intact lac repressor, the lac repressor bound to the gratuitous inducer isopropyl-B-D-1thiogalactoside (IPTG) and the lac repressor complexed with a 21 base pair symmetric operator DNA have been determined. These three structures show the conformation of the molecule in both the induced and the repressed states and provide a framework for understanding a wealth of biochemical and genetic information. The DNA sequence of the lac operon has three lac repressor recognition sites in stretch of 500 base pairs. The crystallographic structure of the complex with DNA suggests that the tetrameric repressor functions synergistically with catabolite gene activator protein (CAP) and participates in the quarternary formation of repression loops in which one tetrameric repressor interacts simultaneously with two sites in the genomic DNA. 76 refs., 11 figs., 1 tab.

  7. Flow-induced Crystallization of Long Chain Aliphatic Polyamides under a Complex Flow Field

    NASA Astrophysics Data System (ADS)

    Dong, Xia; Gao, Yunyun; Wang, Lili; Wang, Dujin

    The present work deals with the flow-induced multiple orientations and crystallization structure of polymer melts under a complex flow field. This complex flow field is characteristic of the consistent coupling of extensional ``pulse'' and closely followed shear flow in a narrow channel. Utilizing an ingenious combination of an advanced micro-injection device and long chain aliphatic polyamides, the flow-induced crystallization morphology was well preserved for ex-situ synchrotron micro-focused wide angle X-ray scattering as well as small angle X-ray scattering. The experimental results clearly indicate that the effect of extensional pulse on the polymer melt is restrained and further diminished due to either the transverse tumble of fountain flow or the rapid retraction of stretched high molecular weight tails. However, the residual shish-kebab structures in the core layer of the far-end of channel suggest that the effect of extensional pulse should be considered in the small-scaled geometries or under the high strain rate condition. The authors thank the financial support from MOST (2013BAE02B02, 2014CB643600) and NSFC(21574140).

  8. Method and apparatus for enhanced sequencing of complex molecules using surface-induced dissociation in conjunction with mass spectrometric analysis

    DOEpatents

    Laskin, Julia [Richland, WA; Futrell, Jean H [Richland, WA

    2008-04-29

    The invention relates to a method and apparatus for enhanced sequencing of complex molecules using surface-induced dissociation (SID) in conjunction with mass spectrometric analysis. Results demonstrate formation of a wide distribution of structure-specific fragments having wide sequence coverage useful for sequencing and identifying the complex molecules.

  9. Mitochondrial complex I inhibition is not required for dopaminergic neuron death induced by rotenone, MPP+, or paraquat

    PubMed Central

    Choi, Won-Seok; Kruse, Shane E.; Palmiter, Richard D.; Xia, Zhengui

    2008-01-01

    Inhibition of mitochondrial complex I is one of the leading hypotheses for dopaminergic neuron death associated with Parkinson's disease (PD). To test this hypothesis genetically, we used a mouse strain lacking functional Ndufs4, a gene encoding a subunit required for complete assembly and function of complex I. Deletion of the Ndufs4 gene abolished complex I activity in midbrain mesencephalic neurons cultured from embryonic day (E) 14 mice, but did not affect the survival of dopaminergic neurons in culture. Although dopaminergic neurons were more sensitive than other neurons in these cultures to cell death induced by rotenone, MPP+, or paraquat treatments, the absence of complex I activity did not protect the dopaminergic neurons, as would be expected if these compounds act by inhibiting complex 1. In fact, the dopaminergic neurons were more sensitive to rotenone. These data suggest that dopaminergic neuron death induced by treatment with rotenone, MPP+, or paraquat is independent of complex I inhibition. PMID:18812510

  10. Efficacy of prothrombin complex concentrates for the emergency reversal of dabigatran-induced anticoagulation.

    PubMed

    Grottke, Oliver; Aisenberg, James; Bernstein, Richard; Goldstein, Patrick; Huisman, Menno V; Jamieson, Dara G; Levy, Jerrold H; Pollack, Charles V; Spyropoulos, Alex C; Steiner, Thorsten; Del Zoppo, Gregory J; Eikelboom, John

    2016-01-01

    Dabigatran is effective in decreasing the risk of ischaemic stroke in patients with atrial fibrillation. However, like all anticoagulants, it is associated with a risk of bleeding. In cases of trauma or emergency surgery, emergency reversal of dabigatran-induced anticoagulation may be required. A specific reversal agent for dabigatran, idarucizumab, has been approved by the US Food and Drug Administration. Alternative reversal agents are available, such as prothrombin complex concentrates (PCCs) and activated PCCs (aPCCs). In this review we evaluate the role of PCCs and aPCCs in the reversal of dabigatran anticoagulation and consider which tests are appropriate for monitoring coagulation in this setting. Pre-clinical studies, small clinical studies and case reports indicate that PCCs and aPCCs may be able to reverse dabigatran-induced anticoagulation in a dose-dependent manner. However, dosing based on coagulation parameters can be difficult because available assays may not provide adequate sensitivity and specificity for measuring anticoagulation induced by dabigatran or the countering effects of PCCs/aPCCs. In addition, PCCs or aPCCs can potentially provoke thromboembolic complications. Despite these limitations and the fact that PCCs and aPCCs are not yet licensed for dabigatran reversal, their use appears to be warranted in patients with life-threatening haemorrhage if idarucizumab is not available. PMID:27125504

  11. Chemistry-specific surface adsorption of the barnacle settlement-inducing protein complex

    PubMed Central

    Petrone, Luigi; Aldred, Nick; Emami, Kaveh; Enander, Karin; Ederth, Thomas; Clare, Anthony S.

    2015-01-01

    Gregarious settlement in barnacle larvae (cyprids) is induced by a contact pheromone, the settlement-inducing protein complex (SIPC). The SIPC has been identified both in the cuticle of adult barnacles and in the temporary adhesive secretion (footprint) of cyprids. Besides acting as a settlement inducer, the presence of the SIPC in footprints points to its additional involvement in the adhesion process. SIPC adsorption behaviour was therefore investigated on a series of self-assembled monolayers (SAMs) by surface plasmon resonance at the pH of seawater (8.3). Fibrinogen and α2-macroglobulin (A2M) (blood complement protease inhibitors with which the SIPC shares 29% sequence homology) were used in the adsorption experiments as positive and negative standards, respectively. The mass uptake of the SIPC was comparable to that of fibrinogen, with adsorption observed even on the protein-resistant oligo(ethylene glycol) surface. Notably, on the positively charged SAM the SIPC showed a kinetic overshoot, indicating a metastable configuration causing the amount of adsorbed protein to temporarily exceed its equilibrium value. A2M adsorption was low or negligible on all SAMs tested, except for the positively charged surface, indicating that A2M adsorption is mainly driven by electrostatics. Evaluation of SIPC non-specific adsorption kinetics revealed that it adsorbed irreversibly and non-cooperatively on all surfaces tested. PMID:25657832

  12. Chemistry-specific surface adsorption of the barnacle settlement-inducing protein complex.

    PubMed

    Petrone, Luigi; Aldred, Nick; Emami, Kaveh; Enander, Karin; Ederth, Thomas; Clare, Anthony S

    2015-02-01

    Gregarious settlement in barnacle larvae (cyprids) is induced by a contact pheromone, the settlement-inducing protein complex (SIPC). The SIPC has been identified both in the cuticle of adult barnacles and in the temporary adhesive secretion (footprint) of cyprids. Besides acting as a settlement inducer, the presence of the SIPC in footprints points to its additional involvement in the adhesion process. SIPC adsorption behaviour was therefore investigated on a series of self-assembled monolayers (SAMs) by surface plasmon resonance at the pH of seawater (8.3). Fibrinogen and α2-macroglobulin (A2M) (blood complement protease inhibitors with which the SIPC shares 29% sequence homology) were used in the adsorption experiments as positive and negative standards, respectively. The mass uptake of the SIPC was comparable to that of fibrinogen, with adsorption observed even on the protein-resistant oligo(ethylene glycol) surface. Notably, on the positively charged SAM the SIPC showed a kinetic overshoot, indicating a metastable configuration causing the amount of adsorbed protein to temporarily exceed its equilibrium value. A2M adsorption was low or negligible on all SAMs tested, except for the positively charged surface, indicating that A2M adsorption is mainly driven by electrostatics. Evaluation of SIPC non-specific adsorption kinetics revealed that it adsorbed irreversibly and non-cooperatively on all surfaces tested. PMID:25657832

  13. Ligand-induced receptor-like kinase complex regulates floral organ abscission in Arabidopsis

    PubMed Central

    Meng, Xiangzong; Zhou, Jinggeng; Tang, Jiao; Li, Bo; de Oliveira, Marcos V. V.; Chai, Jijie; He, Ping; Shan, Libo

    2016-01-01

    SUMMARY Abscission is a developmental process that enables plants to shed unwanted organs. In Arabidopsis, the floral organ abscission is regulated by a signaling pathway consisting of the peptide ligand IDA, the receptor-like kinases (RLKs) HAE and HSL2, and a downstream MAP kinase (MAPK) cascade. However, little is known about the molecular link between ligand-receptor pairs and intracellular signaling. Here, we report that the SERK family RLKs function redundantly in regulating floral organ abscission downstream of IDA and upstream of the MAPK cascade. IDA induces heterodimerization of HAE/HSL2 and SERKs, which transphosphorylate each other. The SERK3 residues mediating its interaction with the immune receptor FLS2 and the brassinosteroid receptor BRI1 are also required for IDA-induced HAE/HSL2-SERK3 interaction, suggesting SERKs serve as co-receptors of HAE/HSL2 in perceiving IDA. Thus, our study reveals the signaling activation mechanism in floral organ abscission by IDA-induced HAE/HSL2-SERK complex formation accompanied by transphosphorylation. PMID:26854226

  14. Induced expression of neuronal membrane attack complex and cell death by Alzheimer's beta-amyloid peptide.

    PubMed

    Shen, Y; Sullivan, T; Lee, C M; Meri, S; Shiosaki, K; Lin, C W

    1998-06-15

    beta-amyloid peptide (A beta) and complement-derived membrane attack complex (MAC) are co-localized in senile plaques of brains from Alzheimer's disease (AD) patients. But the relationship between A beta and complement activation is unclear. We have used human neurotypic cells, differentiated SH-SY5Y, as a model system to examine regulation of neuronal MAC expression and cell death by A beta. We demonstrated that mRNAs (C1q, C2, C3, C4, C5, C6, C7, C8 and C9) and proteins (C1q, C3 and C9) for the major components of the classical complement cascade are present in the SH-SY5Y neurotypic cells, indicating that neuronal cells can synthesize the necessary proteins required for MAC formation. Furthermore, immunocytochemical studies showed the A beta-induced neuronal MAC expression on the SH-SY5Y cells after CD59 was removed by PIPLC or blocked by anti-CD59 antibody. Meanwhile, increased A beta-induced neuronal cell death was observed following treatment with anti-CD59. Taken together, these results suggest that A beta activates neuronal complement cascade to induce MAC, and a deficiency of endogenous complement regulatory proteins, e.g., CD59, may increase the vulnerability of neurons to complement-mediated cytotoxicity. PMID:9689469

  15. Fatty acid nitroalkenes induce resistance to ischemic cardiac injury by modulating mitochondrial respiration at complex II

    PubMed Central

    Koenitzer, Jeffrey R.; Bonacci, Gustavo; Woodcock, Steven R.; Chen, Chen-Shan; Cantu-Medellin, Nadiezhda; Kelley, Eric E.; Schopfer, Francisco J.

    2015-01-01

    Nitro-fatty acids (NO2-FA) are metabolic and inflammatory-derived electrophiles that mediate pleiotropic signaling actions. It was hypothesized that NO2-FA would impact mitochondrial redox reactions to induce tissue-protective metabolic shifts in cells. Nitro-oleic acid (OA-NO2) reversibly inhibited complex II-linked respiration in isolated rat heart mitochondria in a pH-dependent manner and suppressed superoxide formation. Nitroalkylation of Fp subunit was determined by BME capture and the site of modification by OA-NO2 defined by mass spectrometric analysis. These effects translated into reduced basal and maximal respiration and favored glycolytic metabolism in H9C2 cardiomyoblasts as assessed by extracellular H+ and O2 flux analysis. The perfusion of NO2-FA induced acute cardioprotection in an isolated perfused heart ischemia/reperfusion (IR) model as evidenced by significantly higher rate-pressure products. Together these findings indicate that NO2-FA can promote cardioprotection by inducing a shift from respiration to glycolysis and suppressing reactive species formation in the post-ischemic interval. PMID:26722838

  16. Fatty acid nitroalkenes induce resistance to ischemic cardiac injury by modulating mitochondrial respiration at complex II.

    PubMed

    Koenitzer, Jeffrey R; Bonacci, Gustavo; Woodcock, Steven R; Chen, Chen-Shan; Cantu-Medellin, Nadiezhda; Kelley, Eric E; Schopfer, Francisco J

    2016-08-01

    Nitro-fatty acids (NO2-FA) are metabolic and inflammatory-derived electrophiles that mediate pleiotropic signaling actions. It was hypothesized that NO2-FA would impact mitochondrial redox reactions to induce tissue-protective metabolic shifts in cells. Nitro-oleic acid (OA-NO2) reversibly inhibited complex II-linked respiration in isolated rat heart mitochondria in a pH-dependent manner and suppressed superoxide formation. Nitroalkylation of Fp subunit was determined by BME capture and the site of modification by OA-NO2 defined by mass spectrometric analysis. These effects translated into reduced basal and maximal respiration and favored glycolytic metabolism in H9C2 cardiomyoblasts as assessed by extracellular H(+) and O2 flux analysis. The perfusion of NO2-FA induced acute cardioprotection in an isolated perfused heart ischemia/reperfusion (IR) model as evidenced by significantly higher rate-pressure products. Together these findings indicate that NO2-FA can promote cardioprotection by inducing a shift from respiration to glycolysis and suppressing reactive species formation in the post-ischemic interval. PMID:26722838

  17. Transient and persistent pain induced connectivity alterations in pediatric complex regional pain syndrome.

    PubMed

    Linnman, Clas; Becerra, Lino; Lebel, Alyssa; Berde, Charles; Grant, P Ellen; Borsook, David

    2013-01-01

    Evaluation of pain-induced changes in functional connectivity was performed in pediatric complex regional pain syndrome (CRPS) patients. High field functional magnetic resonance imaging was done in the symptomatic painful state and at follow up in the asymptomatic pain free/recovered state. Two types of connectivity alterations were defined: (1) Transient increases in functional connectivity that identified regions with increased cold-induced functional connectivity in the affected limb vs. unaffected limb in the CRPS state, but with normalized connectivity patterns in the recovered state; and (2) Persistent increases in functional connectivity that identified regions with increased cold-induced functional connectivity in the affected limb as compared to the unaffected limb that persisted also in the recovered state (recovered affected limb versus recovered unaffected limb). The data support the notion that even after symptomatic recovery, alterations in brain systems persist, particularly in amygdala and basal ganglia systems. Connectivity analysis may provide a measure of temporal normalization of different circuits/regions when evaluating therapeutic interventions for this condition. The results add emphasis to the importance of early recognition and management in improving outcome of pediatric CRPS. PMID:23526938

  18. Transient and Persistent Pain Induced Connectivity Alterations in Pediatric Complex Regional Pain Syndrome

    PubMed Central

    Linnman, Clas; Becerra, Lino; Lebel, Alyssa; Berde, Charles; Grant, P. Ellen; Borsook, David

    2013-01-01

    Evaluation of pain-induced changes in functional connectivity was performed in pediatric complex regional pain syndrome (CRPS) patients. High field functional magnetic resonance imaging was done in the symptomatic painful state and at follow up in the asymptomatic pain free/recovered state. Two types of connectivity alterations were defined: (1) Transient increases in functional connectivity that identified regions with increased cold-induced functional connectivity in the affected limb vs. unaffected limb in the CRPS state, but with normalized connectivity patterns in the recovered state; and (2) Persistent increases in functional connectivity that identified regions with increased cold-induced functional connectivity in the affected limb as compared to the unaffected limb that persisted also in the recovered state (recovered affected limb versus recovered unaffected limb). The data support the notion that even after symptomatic recovery, alterations in brain systems persist, particularly in amygdala and basal ganglia systems. Connectivity analysis may provide a measure of temporal normalization of different circuits/regions when evaluating therapeutic interventions for this condition. The results add emphasis to the importance of early recognition and management in improving outcome of pediatric CRPS. PMID:23526938

  19. TULP1 Missense Mutations Induces the Endoplasmic Reticulum Unfolded Protein Response Stress Complex (ER-UPR).

    PubMed

    Lobo, Glenn P; Ebke, Lindsey A; Au, Adrian; Hagstrom, Stephanie A

    2016-01-01

    Mutations in the TULP1 gene are associated with early-onset retinitis pigmentosa (RP); however, the molecular mechanisms related to the deleterious effects of TULP1 mutations remains unknown. Several studies have shown that misfolded proteins secondary to genetic mutations can accumulate within the endoplasmic reticulum (ER), causing activation of the unfolded protein response (UPR) complex followed by cellular apoptosis. We hypothesize that TULP1 mutations produce misfolded protein products that accumulate in the ER and induce cellular apoptosis via the UPR. To test our hypothesis, we first performed three in-silico analyses of TULP1 missense mutations (I459K, R420P and F491L), which predicted misfolded protein products. Subsequently, the three mutant TULP1-GFP constructs and wild-type (wt) TULP1-GFP were transiently transfected into hTERT-RPE-1 cells. Staining of cells using ER tracker followed by confocal microscopy showed wt-TULP1 localized predominantly to the cytoplasm and plasma membrane. In contrast, all three mutant TULP1 proteins revealed cytoplasmic punctate staining which co-localized with the ER. Furthermore, western blot analysis of cells expressing mutant TULP1 proteins revealed induction of downstream targets of the ER-UPR complex, including BiP/GPR-78, phosphorylated-PERK (Thr980) and CHOP. Our in-vitro analyses suggest that mutant TULP1 proteins are misfolded and accumulate within the ER leading to induction of the UPR stress response complex. PMID:26427415

  20. 1,10-Phenanthroline promotes copper complexes into tumor cells and induces apoptosis by inhibiting the proteasome activity.

    PubMed

    Zhang, Zhen; Bi, Caifeng; Schmitt, Sara M; Fan, Yuhua; Dong, Lili; Zuo, Jian; Dou, Q Ping

    2012-12-01

    Indole-3-acetic acid and indole-3-propionic acid, two potent natural plant growth hormones, have attracted attention as promising prodrugs in cancer therapy. Copper is known to be a cofactor essential for tumor angiogenesis. We have previously reported that taurine, L-glutamine, and quinoline-2-carboxaldehyde Schiff base copper complexes inhibit cell proliferation and proteasome activity in human cancer cells. In the current study, we synthesized two types of copper complexes, dinuclear complexes and ternary complexes, to investigate whether a certain structure could easily carry copper into cancer cells and consequently inhibit tumor proteasome activity and induce apoptosis. We observed that ternary complexes binding with 1,10-phenanthroline are more potent proteasome inhibitors and apoptosis inducers than dinuclear complexes in PC-3 human prostate cancer cells. Furthermore, the ternary complexes potently inhibit proteasome activity before induction of apoptosis in MDA-MB-231 human breast cancer cells, but not in nontumorigenic MCF-10A cells. Our results suggest that copper complexes binding with 1,10-phenanthroline as the third ligand could serve as potent, selective proteasome inhibitors and apoptosis inducers in tumor cells, and that the ternary complexes may be good potential anticancer drugs. PMID:23053530

  1. Polysaccharide/polynucleotide complexes. Part 6: complementary-strand-induced release of single-stranded DNA bound in the schizophyllan complex.

    PubMed

    Koumoto, Kazuya; Mizu, Masami; Sakurai, Kazuo; Kunitake, Toyoki; Shinkai, Seiji

    2004-03-01

    Spectroscopic properties of single-stranded DNA/schizophyllan ternary complexes (ss-DNA2s-SPG), induced by addition of either complementary or noncomplementary strands, have been investigated. The addition of the complementary strands to ss-DNA2s-SPG induced the quick release of the bound ss-DNA to the complementary strands (both DNA and RNA), whereas the ternary complex was unaffected upon addition of noncomplementary strands. Our experiments imply that SPG has complexation properties indispensable to the gene carriers. As far as we know, there is no report on exploitation of such nonviral gene carriers that can accomplish an intelligent release of the bound ss-DNA toward the complementary strands. We believe, therefore, that SPG, a natural and neutral polysaccharide, has a great potential to become a new ss-DNA carrier. PMID:17191866

  2. Pyrrolidine dithiocarbamate-zinc(II) and -copper(II) complexes induce apoptosis in tumor cells by inhibiting the proteasomal activity

    SciTech Connect

    Milacic, Vesna; Chen Di; Giovagnini, Lorena; Diez, Alejandro; Fregona, Dolores; Dou, Q. Ping

    2008-08-15

    Zinc and copper are trace elements essential for proper folding, stabilization and catalytic activity of many metalloenzymes in living organisms. However, disturbed zinc and copper homeostasis is reported in many types of cancer. We have previously demonstrated that copper complexes induced proteasome inhibition and apoptosis in cultured human cancer cells. In the current study we hypothesized that zinc complexes could also inhibit the proteasomal chymotrypsin-like activity responsible for subsequent apoptosis induction. We first showed that zinc(II) chloride was able to inhibit the chymotrypsin-like activity of a purified 20S proteasome with an IC{sub 50} value of 13.8 {mu}M, which was less potent than copper(II) chloride (IC{sub 50} 5.3 {mu}M). We then compared the potencies of a pyrrolidine dithiocarbamate (PyDT)-zinc(II) complex and a PyDT-copper(II) complex to inhibit cellular proteasomal activity, suppress proliferation and induce apoptosis in various human breast and prostate cancer cell lines. Consistently, zinc complex was less potent than copper complex in inhibiting the proteasome and inducing apoptosis. Additionally, zinc and copper complexes appear to use somewhat different mechanisms to kill tumor cells. Zinc complexes were able to activate calpain-, but not caspase-3-dependent pathway, while copper complexes were able to induce activation of both proteases. Furthermore, the potencies of these PyDT-metal complexes depend on the nature of metals and also on the ratio of PyDT to the metal ion within the complex, which probably affects their stability and availability for interacting with and inhibiting the proteasome in tumor cells.

  3. Pyrrolidine dithiocarbamate-zinc(II) and -copper(II) complexes induce apoptosis in tumor cells by inhibiting the proteasomal activity☆

    PubMed Central

    Milacic, Vesna; Chen, Di; Giovagnini, Lorena; Diez, Alejandro; Fregona, Dolores; Dou, Q. Ping

    2013-01-01

    Zinc and copper are trace elements essential for proper folding, stabilization and catalytic activity of many metalloenzymes in living organisms. However, disturbed zinc and copper homeostasis is reported in many types of cancer. We have previously demonstrated that copper complexes induced proteasome inhibition and apoptosis in cultured human cancer cells. In the current study we hypothesized that zinc complexes could also inhibit the proteasomal chymotrypsin-like activity responsible for subsequent apoptosis induction. We first showed that zinc(II) chloride was able to inhibit the chymotrypsin-like activity of a purified 20S proteasome with an IC50 value of 13.8 μM, which was less potent than copper(II) chloride (IC50 5.3 μM). We then compared the potencies of a pyrrolidine dithiocarbamate (PyDT)-zinc(II) complex and a PyDT-copper(II) complex to inhibit cellular proteasomal activity, suppress proliferation and induce apoptosis in various human breast and prostate cancer cell lines. Consistently, zinc complex was less potent than copper complex in inhibiting the proteasome and inducing apoptosis. Additionally, zinc and copper complexes appear to use somewhat different mechanisms to kill tumor cells. Zinc complexes were able to activate calpain-, but not caspase-3-dependent pathway, while copper complexes were able to induce activation of both proteases. Furthermore, the potencies of these PyDT-metal complexes depend on the nature of metals and also on the ratio of PyDT to the metal ion within the complex, which probably affects their stability and availability for interacting with and inhibiting the proteasome in tumor cells. PMID:18501397

  4. Influence of pore fluid chemistry on the complex conductivity and induced polarization responses of Berea sandstone

    NASA Astrophysics Data System (ADS)

    Lesmes, David P.; Frye, Kevin M.

    2001-01-01

    The spectral induced-polarization (IP) response of rocks and soils is a complex function of pore solution chemistry, sample microgeometry, and surface chemical properties. We measure the complex conductivity and the time domain IP responses of Berea sandstone as a function of pore fluid ionic strength and pH. Complex conductivity is measured over the frequency range 10-3 to 106 Hz, and chargeability is computed using a time window of 0.16 to 1.74 s. The field IP parameters: phase, percent frequency effect, and chargeability are functions of both the surface and bulk electrical properties of the sample and are observed to decrease with increasing solution conductivity. Dividing these parameters by the sample resistivity yields normalized IP parameters (quadrature conductivity, metal factor, normalized chargeability) that are proportional to the imaginary component of the complex surface conductivity. Normalized IP parameters increase with ionic strength up to concentrations of 10-1 M NaCl and show a reduced response at pH 3, the point of zero charge for quartz-dominated systems. For concentrations >10-1 M NaCl, the normalized parameters decrease with increasing concentration. This decrease in surface polarization may indicate a decrease in the effective mobility of polarizing charges at high solution concentration. Our data indicate that normalized IP parameters are directly related to the physiochemical parameters that control the surface conductivity responses of rocks and soils. Normalization of IP measurements in environmental investigations should increase the effectiveness of IP surveys, especially in high-conductivity environments.

  5. Detecting drug-induced prolongation of the QRS complex: New insights for cardiac safety assessment

    SciTech Connect

    Cros, C.; Skinner, M.; Moors, J.; Lainee, P.; Valentin, J.P.

    2012-12-01

    Background: Drugs slowing the conduction of the cardiac action potential and prolonging QRS complex duration by blocking the sodium current (I{sub Na}) may carry pro-arrhythmic risks. Due to the frequency-dependent block of I{sub Na}, this study assesses whether activity-related spontaneous increases in heart rate (HR) occurring during standard dog telemetry studies can be used to optimise the detection of class I antiarrhythmic-induced QRS prolongation. Methods: Telemetered dogs were orally dosed with quinidine (class Ia), mexiletine (class Ib) or flecainide (class Ic). QRS duration was determined standardly (5 beats averaged at rest) but also prior to and at the plateau of each acute increase in HR (3 beats averaged at steady state), and averaged over 1 h period from 1 h pre-dose to 5 h post-dose. Results: Compared to time-matched vehicle, at rest, only quinidine and flecainide induced increases in QRS duration (E{sub max} 13% and 20% respectively, P < 0.01–0.001) whereas mexiletine had no effect. Importantly, the increase in QRS duration was enhanced at peak HR with an additional effect of + 0.7 ± 0.5 ms (quinidine, NS), + 1.8 ± 0.8 ms (mexiletine, P < 0.05) and + 2.8 ± 0.8 ms (flecainide, P < 0.01) (calculated as QRS at basal HR-QRS at high HR). Conclusion: Electrocardiogram recordings during elevated HR, not considered during routine analysis optimised for detecting QT prolongation, can be used to sensitise the detection of QRS prolongation. This could prove useful when borderline QRS effects are detected. Analysing during acute increases in HR could also be useful for detecting drug-induced effects on other aspects of cardiac function. -- Highlights: ► We aimed to improve detection of drug-induced QRS prolongation in safety screening. ► We used telemetered dogs to test class I antiarrhythmics at low and high heart rate. ► At low heart rate only quinidine and flecainide induced an increase in QRS duration. ► At high heart rate the effects of two

  6. COMPLEX RESISTIVITY OF FAULT GOUGE AND ITS SIGNIFICANCE FOR EARTHQUAKE LIGHTS AND INDUCED POLARIZATION.

    USGS Publications Warehouse

    Lockner, David A.; Byerlee, James D.

    1985-01-01

    The authors measured complex resistivity of 2 water-saturated San Andreas fault gouges from 10** minus **3 to 10**6 Hz and confining pressures of 0. 2 to 200 MPa. Consistent with earlier observations of clays and common rocks, large low-frequency permittivities were observed in all cases. Comparisons were made to induced polarization (IP) measurements by inversion of the data into the time domain, where it was found that principal features of the IP response curves were due to these large low-frequency permittivities. The results also suggest that following large earthquakes, significant electrical charge could remain for many seconds and could result in a variety of reported electromagnetic effects. Refs.

  7. Formation of impeller-like helical DNA–silica complexes by polyamines induced chiral packing

    PubMed Central

    Liu, Ben; Han, Lu; Che, Shunai

    2012-01-01

    The helicity of DNA and its long-range chiral packing are widespread phenomena; however, the packing mechanism remains poorly understood both in vivo and in vitro. Here, we report the extraordinary DNA chiral self-assembly by silica mineralization, together with circular dichroism measurements and electron microscopy studies on the structure and morphology of the products. Mg2+ ion and diethylenetriamine were found to induce right- and left-handed chiral DNA packing with two-dimensional-square p4mm mesostructures, respectively, to give corresponding enantiomeric impeller-like helical DNA–silica complexes. Moreover, formation of macroscopic impeller-like helical architectures depends on the types of polyamines and co-structure-directing agents and pH values of reaction solution. It has been suggested that interaction strength between negatively charged DNA phosphate strands and positively charged counterions may be the key factor for the induction of DNA packing handedness. PMID:24098845

  8. Stellate ganglion pulsed radiofrequency ablation for stretch induced complex regional pain syndrome type II

    PubMed Central

    Singh Rana, Shiv Pratap; Abraham, Mary; Gupta, Varun; Biswas, Shubhashish; Marda, Manish

    2015-01-01

    Complex regional pain syndrome (CRPS) following injury or nerve damage, as its name signifies, is a challenging entity, and its successful management requires a multidisciplinary approach. It not only manifests as severe pain, but also gives rise to functional disability, lack of sleep, lack of enjoyment of life and poor quality of life. Various pain interventional techniques have been described in the literature for the management of CRPS ranging from sympathetic blocks to spinal cord stimulator. A 34-year-old liver transplant donor, who developed position-induced right upper limb neuropathic pain suggestive of CRPS type II was managed initially with medications and later with stellate ganglion block under fluoroscopic guidance at cervical C7 position. Following an initial significant improvement in pain and allodynia, which was transient, a pulsed radiofrequency ablation of stellate ganglion was performed successfully to provide prolonged and sustained pain relief, which persisted up to 14 months of follow-up. PMID:26543471

  9. Complexity of lectin-mediated reactions in bacteria-induced histamine release.

    PubMed

    Jensen, C; Stahl Skov, P; Norn, S; Espersen, F; Bøg-Hansen, T C; Lihme, A

    1984-08-01

    We have earlier suggested that bacteria-induced histamine release is caused by different mechanisms, including allergic and non-immunological mechanisms, and that the latter probably depends on lectin-mediated reactions. Two possibilities of lectin-mediated reactions were examined in this study, bacterial surface lectins bind to sugars on the basophil cell membrane leading to histamine release, and the reverse reaction where bacterial aminosugars react with lectins on the basophil cell surface. In the bacterial histamine release caused by the Staph. aureus strain Wood 46 it was possible to demonstrate a reverse reaction, but not a bacterial lectin-mediated reaction. The reaction seems to be complex, as lower concentrations of sugars might potentiate the release of histamine by binding to the target cell or bacteria, while the release is inhibited by higher concentrations. PMID:6208803

  10. Apoptosis induced by granzyme B-glycosaminoglycan complexes: implications for granule-mediated apoptosis in vivo.

    PubMed

    Galvin, J P; Spaeny-Dekking, L H; Wang, B; Seth, P; Hack, C E; Froelich, C J

    1999-05-01

    Lymphocyte granule-mediated apoptosis occurs by perforin-mediated intracellular delivery of granule-associated serine proteases (granzymes). A granule-associated proteoglycan, namely serglycin, that contains chondroitin 4-sulfate (CS) glycosaminoglycans is present in the granules of cytotoxic cells. Serglycin acts as scaffold for packaging the positively charged granzymes and probably chaperones the proteases secreted extracellularly. To learn how the interaction of granzyme B (GrB) with serglycin might influence the apoptotic potential of this proteases, we have evaluated a model system where desalted CS is combined with isolated human granzyme. CS-GrB complexes were very stable, remaining undissociated in salt concentrations upwards to 500 mM (pH 7.4). On the basis of a capture enzyme immunoassay that accurately detects GrB, equivalent amounts of active free and CS-GrB, delivered by perforin or adenovirus, efficiently induced apoptosis in Jurkat cells and produced a similar time-dependent increase in caspase-3-like activity. CS-GrB processed isolated caspases-3 and -7 less efficiently than free granzyme. However, when added to cytosolic extracts, rates of processing were nearly equivalent for the two forms, suggesting cationic GrB may nonspecifically bind cytosolic proteins, leading to reduce proteolytic activity. Finally, GrB was found to be exocytosed from lymphocyte-activated killer cells as a neutral, high macromolecular weight complex, which possessed apoptotic activity. Collectively, the results indicate that neutral, high m.w. GrB has the capacity to induce cell death and will be useful to study the mechanism of cytotoxic cell-mediated apoptosis in vitro. PMID:10228010

  11. Soluble, Prefibrillar α-Synuclein Oligomers Promote Complex I-dependent, Ca2+-induced Mitochondrial Dysfunction*

    PubMed Central

    Luth, Eric S.; Stavrovskaya, Irina G.; Bartels, Tim; Kristal, Bruce S.; Selkoe, Dennis J.

    2014-01-01

    α-Synuclein (αSyn) aggregation and mitochondrial dysfunction both contribute to the pathogenesis of Parkinson disease (PD). Although recent studies have suggested that mitochondrial association of αSyn may disrupt mitochondrial function, it is unclear what aggregation state of αSyn is most damaging to mitochondria and what conditions promote or inhibit the effect of toxic αSyn species. Because the neuronal populations most vulnerable in PD are characterized by large cytosolic Ca2+ oscillations that burden mitochondria, we examined mitochondrial Ca2+ stress in an in vitro system comprising isolated mitochondria and purified recombinant human αSyn in various aggregation states. Using fluorimetry to simultaneously measure four mitochondrial parameters, we observed that soluble, prefibrillar αSyn oligomers, but not monomeric or fibrillar αSyn, decreased the retention time of exogenously added Ca2+, promoted Ca2+-induced mitochondrial swelling and depolarization, and accelerated cytochrome c release. Inhibition of the permeability transition pore rescued these αSyn-induced changes in mitochondrial parameters. Interestingly, the mitotoxic effects of αSyn were specifically dependent upon both electron flow through complex I and mitochondrial uptake of exogenous Ca2+. Our results suggest that soluble prefibrillar αSyn oligomers recapitulate several mitochondrial phenotypes previously observed in animal and cell models of PD: complex I dysfunction, altered membrane potential, disrupted Ca2+ homeostasis, and enhanced cytochrome c release. These data reveal how the association of oligomeric αSyn with mitochondria can be detrimental to the function of cells with high Ca2+-handling requirements. PMID:24942732

  12. The DREAM complex mediates GIST cell quiescence and is a novel therapeutic target to enhance imatinib-induced apoptosis.

    PubMed

    Boichuk, Sergei; Parry, Joshua A; Makielski, Kathleen R; Litovchick, Larisa; Baron, Julianne L; Zewe, James P; Wozniak, Agnieszka; Mehalek, Keith R; Korzeniewski, Nina; Seneviratne, Danushka S; Schöffski, Patrick; Debiec-Rychter, Maria; DeCaprio, James A; Duensing, Anette

    2013-08-15

    Gastrointestinal stromal tumors (GIST) can be successfully treated with imatinib mesylate (Gleevec); however, complete remissions are rare and patients frequently achieve disease stabilization in the presence of residual tumor masses. The clinical observation that discontinuation of treatment can lead to tumor progression suggests that residual tumor cells are, in fact, quiescent and, therefore, able to re-enter the cell-division cycle. In line with this notion, we have previously shown that imatinib induces GIST cell quiescence in vitro through the APC(CDH1)-SKP2-p27(Kip1) signaling axis. Here, we provide evidence that imatinib induces GIST cell quiescence in vivo and that this process also involves the DREAM complex, a multisubunit complex that has recently been identified as an additional key regulator of quiescence. Importantly, inhibition of DREAM complex formation by depletion of the DREAM regulatory kinase DYRK1A or its target LIN52 was found to enhance imatinib-induced cell death. Our results show that imatinib induces apoptosis in a fraction of GIST cells while, at the same time, a subset of cells undergoes quiescence involving the DREAM complex. Inhibition of this process enhances imatinib-induced apoptosis, which opens the opportunity for future therapeutic interventions to target the DREAM complex for more efficient imatinib responses. PMID:23786773

  13. Inducer effect on the complex formation between rat liver nuclear proteins and cytochrome P450 2B gene regulatory elements.

    PubMed

    Duzhak, T G; Schwartz, E I; Gulyaeva, L F; Lyakhovich, V V

    2002-09-01

    DNA gel retardation assay has been applied to the investigation of complexes between rat liver nuclear proteins and Barbie box positive regulatory element of cytochrome P450 2B (CYP2B) genes. The intensities of B1 and B2 bands detected in the absence of an inducer increased after 30 min protein incubation with phenobarbital (PB) or triphenyldioxane (TPD), but not with 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOPOB). In addition, a new complex (B3 band) was for the first time detected under induction by PB, TPD, and TCPOPOB. Increase in the incubation time up to 2 h facilitated the formation of other new complexes (B4 and B5 bands), which were detected only in the presence of TPD. The use of [3H]TPD in hybridization experiments revealed that this inducer, capable of binding to Barbie box DNA, is also present in B4 and B5 complexes. It is probable that the investigated compounds activate the same proteins at the initial induction steps, which correlates with the formation of B1, B2, and B3 complexes. The further induction step might be inducer-specific, as indicated by the formation of B4 and B5 complexes in the presence of TPD only. Thus, the present data suggest the possibility of specific gene activation signaling pathways that are dependent on a particular inducer. PMID:12387719

  14. Light-Induced Infrared Difference Spectroscopy in the Investigation of Light Harvesting Complexes.

    PubMed

    Mezzetti, Alberto

    2015-01-01

    Light-induced infrared difference spectroscopy (IR-DS) has been used, especially in the last decade, to investigate early photophysics, energy transfer and photoprotection mechanisms in isolated and membrane-bound light harvesting complexes (LHCs). The technique has the definite advantage to give information on how the pigments and the other constituents of the biological system (proteins, membranes, etc.) evolve during a given photoreaction. Different static and time-resolved approaches have been used. Compared to the application of IR-DS to photosynthetic Reaction Centers (RCs), however, IR-DS applied to LHCs is still in an almost pioneering age: very often sophisticated techniques (step-scan FTIR, ultrafast IR) or data analysis strategies (global analysis, target analysis, multivariate curve resolution) are needed. In addition, band assignment is usually more complicated than in RCs. The results obtained on the studied systems (chromatophores and RC-LHC supercomplexes from purple bacteria; Peridinin-Chlorophyll-a-Proteins from dinoflagellates; isolated LHCII from plants; thylakoids; Orange Carotenoid Protein from cyanobacteria) are summarized. A description of the different IR-DS techniques used is also provided, and the most stimulating perspectives are also described. Especially if used synergically with other biophysical techniques, light-induced IR-DS represents an important tool in the investigation of photophysical/photochemical reactions in LHCs and LHC-containing systems. PMID:26151118

  15. Experimental investigation of flow induced dust acoustic shock waves in a complex plasma

    NASA Astrophysics Data System (ADS)

    Jaiswal, S.; Bandyopadhyay, P.; Sen, A.

    2016-08-01

    We report on experimental observations of flow induced large amplitude dust-acoustic shock waves in a complex plasma. The experiments have been carried out in a Π shaped direct current glow discharge experimental device using kaolin particles as the dust component in a background of Argon plasma. A strong supersonic flow of the dust fluid is induced by adjusting the pumping speed and neutral gas flow into the device. An isolated copper wire mounted on the cathode acts as a potential barrier to the flow of dust particles. A sudden change in the gas flow rate is used to trigger the onset of high velocity dust acoustic shocks whose dynamics are captured by fast video pictures of the evolving structures. The physical characteristics of these shocks are delineated through a parametric scan of their dynamical properties over a range of flow speeds and potential hill heights. The observed evolution of the shock waves and their propagation characteristics are found to compare well with model numerical results based on a modified Korteweg-de-Vries-Burgers type equation.

  16. Design of off-axis mirrors for the phase-induced amplitude apodization complex mask coronagraph

    NASA Astrophysics Data System (ADS)

    Pluzhnik, Eugene; Guyon, Olivier; Belikov, Ruslan; Bendek, Eduardo

    2016-01-01

    The phase-induced amplitude apodization complex mask coronagraph (PIAACMC) provides an efficient way to control diffraction propagation effects caused by the central obstruction/segmented mirrors of the telescope. PIAACMC can be optimized in a way that takes into account both chromatic diffraction effects caused by the telescope obstructed aperture and the tip-tilt sensitivity of the coronagraph. As a result, unlike classic phase-induced amplitude apodization (PIAA), the PIAACMC mirror shapes are often slightly asymmetric even for an on-axis configuration and require more care in calculating off-axis shapes when an off-axis configuration is preferred. A method to design off-axis PIAA mirror shapes given an on-axis mirror design is presented. The algorithm is based on geometrical ray tracing and is able to calculate off-axis PIAA mirror shapes for an arbitrary geometry of the input and output beams. The method is demonstrated using the third generation PIAACMC design for WFIRST-AFTA telescope. Geometrical optics design issues related to the off-axis diffraction propagation effects are also discussed.

  17. Trophic Complexity and the Adaptive Value of Damage-Induced Plant Volatiles

    PubMed Central

    Kaplan, Ian

    2012-01-01

    Indirect plant defenses are those facilitating the action of carnivores in ridding plants of their herbivorous consumers, as opposed to directly poisoning or repelling them. Of the numerous and diverse indirect defensive strategies employed by plants, inducible volatile production has garnered the most fascination among plant-insect ecologists. These volatile chemicals are emitted in response to feeding by herbivorous arthropods and serve to guide predators and parasitic wasps to their prey. Implicit in virtually all discussions of plant volatile-carnivore interactions is the premise that plants “call for help” to bodyguards that serve to boost plant fitness by limiting herbivore damage. This, by necessity, assumes a three-trophic level food chain where carnivores benefit plants, a theoretical framework that is conceptually tractable and convenient, but poorly depicts the complexity of food-web dynamics occurring in real communities. Recent work suggests that hyperparasitoids, top consumers acting from the fourth trophic level, exploit the same plant volatile cues used by third trophic level carnivores. Further, hyperparasitoids shift their foraging preferences, specifically cueing in to the odor profile of a plant being damaged by a parasitized herbivore that contains their host compared with damage from an unparasitized herbivore. If this outcome is broadly representative of plant-insect food webs at large, it suggests that damage-induced volatiles may not always be beneficial to plants with major implications for the evolution of anti-herbivore defense and manipulating plant traits to improve biological control in agricultural crops. PMID:23209381

  18. Bacteriophage T4 Mutants Hypersensitive to an Antitumor Agent That Induces Topoisomerase-DNA Cleavage Complexes

    PubMed Central

    Woodworth, D. L.; Kreuzer, K. N.

    1996-01-01

    Many antitumor agents and antibiotics affect cells by interacting with type II topoisomerases, stabilizing a covalent enzyme-DNA complex. A pathway of recombination can apparently repair this DNA damage. In this study, transposon mutagenesis was used to identify possible components of the repair pathway in bacteriophage T4. Substantial increases in sensitivity to the antitumor agent m-AMSA [4'-(9-acridinyl-amino) methanesulfon-m-anisidide] were found with transposon insertion mutations that inactivate any of six T4-encoded proteins: UvsY (DNA synaptase accessory protein), UvsW (unknown function), Rnh (RNase H and 5' to 3' DNA exonuclease), α-gt (α-glucosyl transferase), gp47.1 (uncharacterized), and NrdB (β subunit of ribonucleotide reductase). The role of the rnh gene in drug sensitivity was further characterized. First, an in-frame rnh deletion mutation was constructed and analyzed, providing evidence that the absence of Rnh protein causes hypersensitivity to m-AMSA. Second, the m-AMSA sensitivity of the rnh-deletion mutant was shown to require a drug-sensitive T4 topoisomerase. Third, analysis of double mutants suggested that uvsW and rnh mutations impair a common step in the recombinational repair pathway for m-AMSA-induced damage. Finally, the rnh-deletion mutant was found to be hypersensitive to UV, implicating Rnh in recombinational repair of UV-induced damage. PMID:8807283

  19. Structural and thermodynamic basis of proline-induced transmembrane complex stabilization

    PubMed Central

    Schmidt, Thomas; Situ, Alan J.; Ulmer, Tobias S.

    2016-01-01

    In membrane proteins, proline-mediated helix kinks are indispensable for the tight packing of transmembrane (TM) helices. However, kinks invariably affect numerous interhelical interactions, questioning the acceptance of proline substitutions and evolutionary origin of kinks. Here, we present the structural and thermodynamic basis of proline-induced integrin αIIbβ3 TM complex stabilization to understand the introduction of proline kinks in membrane proteins. In phospholipid bicelles, the A711P substitution in the center of the β3 TM helix changes the direction of adjacent helix segments to form a 35 ± 2° angle and predominantly repacks the segment in the inner membrane leaflet due to a swivel movement. This swivel repacks hydrophobic and electrostatic interhelical contacts within intracellular lipids, resulting in an overall TM complex stabilization of −0.82 ± 0.01 kcal/mol. Thus, proline substitutions can directly stabilize membrane proteins and such substitutions are proposed to follow the structural template of integrin αIIbβ3(A711P). PMID:27436065

  20. Syncytial apoptosis signaling network induced by the HIV-1 envelope glycoprotein complex: an overview.

    PubMed

    Nardacci, R; Perfettini, J-L; Grieco, L; Thieffry, D; Kroemer, G; Piacentini, M

    2015-01-01

    Infection by human immunodeficiency virus-1 (HIV-1) is associated with a progressive decrease in CD4 T-cell numbers and the consequent collapse of host immune defenses. The major pathogenic mechanism of AIDS is the massive apoptotic destruction of the immunocompetent cells, including uninfected cells. The latter process, also known as by-stander killing, operates by various mechanisms one of which involves the formation of syncytia which undergo cell death by following a complex pathway. We present here a detailed and curated map of the syncytial apoptosis signaling network, aimed at simplifying the whole mechanism that we have characterized at the molecular level in the last 15 years. The map was created using Systems Biology Graphical Notation language with the help of CellDesigner software and encompasses 36 components (proteins/genes) and 54 interactions. The simplification of this complex network paves the way for the development of novel therapeutic strategies to eradicate HIV-1 infection. Agents that induce the selective death of HIV-1-elicited syncytia might lead to the elimination of viral reservoirs and hence constitute an important complement to current antiretroviral therapies. PMID:26247731

  1. Decoherence induced by conical intersections: complexity constrained quantum dynamics of photoexcited pyrazine.

    PubMed

    Westermann, Till; Manthe, Uwe

    2012-12-14

    Decoherence effects induced by conical intersecting potential energy surfaces are studied employing the correlation-based von Neumann (CvN) entropy which provides a measure of the complexity of the underlying wavefunction. As a prototypical example, the S(0) → S(2) excitation in pyrazine is investigated. The 24-dimensional wavepacket dynamics calculations presented utilize the multi-layer extension of the multi-configurational time-dependent Hartree (MCTDH) approach. An efficient numerical scheme is introduced which facilitates CvN entropy constrained wavepacket propagation within the multi-layer MCTDH approach. In unconstrained multi-layer MCTDH calculations, the CvN-entropy is found to provide a valuable analytical tool for studying the decoherence phenomena present. Investigating the CvN entropy after the S(0) → S(2) excitation as a function of time, a clear separation of time scales is obtained. It can be related to the different dynamical phenomena present: the initial transfer from the upper (S(2)) to the lower (S(1)) adiabatic electronic states rapidly generates vast amounts of CvN-entropy, while the subsequent motion on the anharmonic lower adiabatic potential energy surface only yields a slow increase of the CvN-entropy. Employing CvN-entropy constrained calculations, the sensitivity of the autocorrelation function, the absorption spectrum, and the diabatic electronic population dynamics to complexity constraints is analyzed in detail. PMID:23249046

  2. Di-hydrogen contact induced lattice instabilities and structural dynamics in complex hydride perovskites.

    PubMed

    Schouwink, P; Hagemann, H; Embs, J P; D'Anna, V; Černý, R

    2015-07-01

    The structural phase transitions occurring in a series of perovskite-type complex hydrides based on the tetrahydroborate anion BH4(-) are investigated by means of in situ synchrotron x-ray powder diffraction, vibrational spectroscopy, thermal methods and ab initio calculations in the solid state. Structural dynamics of the BH4 anion are followed with quasi-elastic neutron scattering. We show that unexpected temperature-induced lattice instabilities in perovskite-type ACa(BH4)3 (A = K, Rb, Cs) have their origin in close hydridic di-hydrogen contacts. The rich lattice dynamics lead to coupling between internal B-H vibrations and phonons, resulting in distortions in the high-temperature polymorph that are identical in symmetry to well-known instabilities in oxide perovskites, generally condensing at lower temperatures. It is found that anion-substitution BH4(-) <-> (X = Halide) can relax distortions in ACa(BH4)3 by eliminating coulomb repulsive H(-)···H(-) effects. The interesting nature of phase transition in ACa(BH4)3 enters an unexplored field of weak interactions in ceramic-like host lattices and is the principal motivation for this study. Close di-hydrogen contacts suggest new concepts to tailor crystal symmetries in complex hydride perovskites in the future. PMID:26076047

  3. Capturing microRNA targets using an RNA-induced silencing complex (RISC)-trap approach

    PubMed Central

    Cambronne, Xiaolu A.; Shen, Rongkun; Auer, Paul L.; Goodman, Richard H.

    2012-01-01

    Identifying targets is critical for understanding the biological effects of microRNA (miRNA) expression. The challenge lies in characterizing the cohort of targets for a specific miRNA, especially when targets are being actively down-regulated in miRNA– RNA-induced silencing complex (RISC)–messengerRNA (mRNA) complexes. We have developed a robust and versatile strategy called RISCtrap to stabilize and purify targets from this transient interaction. Its utility was demonstrated by determining specific high-confidence target datasets for miR-124, miR-132, and miR-181 that contained known and previously unknown transcripts. Two previously unknown miR-132 targets identified with RISCtrap, adaptor protein CT10 regulator of kinase 1 (CRK1) and tight junction-associated protein 1 (TJAP1), were shown to be endogenously regulated by miR-132 in adult mouse forebrain. The datasets, moreover, differed in the number of targets and in the types and frequency of microRNA recognition element (MRE) motifs, thus revealing a previously underappreciated level of specificity in the target sets regulated by individual miRNAs. PMID:23184980

  4. Syncytial apoptosis signaling network induced by the HIV-1 envelope glycoprotein complex: an overview

    PubMed Central

    Nardacci, R; Perfettini, J-L; Grieco, L; Thieffry, D; Kroemer, G; Piacentini, M

    2015-01-01

    Infection by human immunodeficiency virus-1 (HIV-1) is associated with a progressive decrease in CD4 T-cell numbers and the consequent collapse of host immune defenses. The major pathogenic mechanism of AIDS is the massive apoptotic destruction of the immunocompetent cells, including uninfected cells. The latter process, also known as by-stander killing, operates by various mechanisms one of which involves the formation of syncytia which undergo cell death by following a complex pathway. We present here a detailed and curated map of the syncytial apoptosis signaling network, aimed at simplifying the whole mechanism that we have characterized at the molecular level in the last 15 years. The map was created using Systems Biology Graphical Notation language with the help of CellDesigner software and encompasses 36 components (proteins/genes) and 54 interactions. The simplification of this complex network paves the way for the development of novel therapeutic strategies to eradicate HIV-1 infection. Agents that induce the selective death of HIV-1-elicited syncytia might lead to the elimination of viral reservoirs and hence constitute an important complement to current antiretroviral therapies. PMID:26247731

  5. The Fine Structure of Experimentally Induced Connective Tissue Complexes in the Human

    PubMed Central

    Stinson, W. W.; Richter, K. M.; Schilling, J. A.

    1974-01-01

    The growth, development and cellular activity of fibrocollagenous tissue complexes induced by the implantation of specially structured wire mesh cylinders in 22 human male volunteers were studied during the time course of fibroplasia utilizing light and electron microscopic techniques. The fibrocollagenous tissue complexes after 4 to 16 weeks of development demonstrated highly ordered lamellations made of zones consisting primarily of fibroblasts and zones consisting primarily of collagenous fibers. The development of the ordered lamellations is referable to specific fibrillogenic activities by the constituent fibroblasts. The initial role of the fibroblast in fibrillogenesis is indicative of an apocrine-like secretory process followed by a holocrine-like role which results in cytodestruction and concurrent formation of an avascular collagenic tissue referable to an organizing cicatrix in a healing wound. ImagesFigs. 1-3.Figs. 4-9.Fig. 10.Fig. 11.Fig. 12.Figs. 13, 14.Fig. 15.Fig. 16.Fig. 17.Fig. 18, 19.Figs. 20-22.Fig. 23.Fig. 24. PMID:4599224

  6. Regulatory effects of interleukin-6 in immunoglobulin G immune-complex-induced lung injury.

    PubMed Central

    Shanley, T. P.; Foreback, J. L.; Remick, D. G.; Ulich, T. R.; Kunkel, S. L.; Ward, P. A.

    1997-01-01

    Interleukin-6 (IL-6) is a cytokine produced in response to a variety of inflammatory stimuli. Although IL-6 is often observed in increased amounts in acute respiratory distress syndrome, its role in the development of lung injury is unclear. The role of IL-6 was studied in the rat model of lung injury induced by the intra-alveolar deposition of IgG immune complexes. IL-6 induction, as determined by Northern blot analysis and bioactivity, was found as a function of time during the course of development of injury. Recombinant IL-6 instilled intratracheally at commencement of injury led to substantial reductions in lung vascular permeability, neutrophil accumulation, and levels of tumor necrosis factor (TNF)-alpha and macrophage inflammatory protein (MIP)-2 in bronchoalveolar lavage fluids. Conversely, blocking of intrinsic IL-6 by a neutralizing antibody resulted in increases in lung vascular permeability, neutrophil content, and TNF-alpha levels in bronchoalveolar lavage fluids. Rat alveolar macrophages stimulated in vitro with lipopolysaccharide in the presence of IL-6 showed a significant reduction in TNF-alpha expression. Together, these findings suggest that IL-6 acts as an intrinsic regulator of lung inflammatory injury after deposition of IgG immune complexes and that the protective effects of exogenously administered IL-6 may be in part linked to suppressed TNF-alpha production. Images Figure 1 Figure 4 PMID:9212745

  7. Modulation of flash-induced photosystem II fluorescence by events occurring at the water oxidizing complex.

    PubMed

    Putrenko, I I; Vasil'ev, S; Bruce, D

    1999-08-17

    The mechanism of flash-induced changes with a periodicity of four in photosystem II (PSII) fluorescence was investigated with the aim of further using fluorescence measurements as an approach to studying the structural and functional organization of the water-oxidizing complex (WOC). The decay of the flash-induced high fluorescence state of PSII was measured with pulse amplitude modulated fluorometry in thylakoids and PSII enriched membrane fragments. Calculated QA- decay was well described by three exponential decay components, reflecting QA- reoxidation with halftimes of 450 and 860 micros, 2 and 7.6 ms, and 111 and 135 ms in thylakoids and PSII membranes, respectively. The effect of modification of the PSII donor side by changing pH or by removal of the extrinsic 17 and 24 kDa proteins on period four oscillations in both maximum fluorescence yield and the relative contribution of QA- reoxidation reactions was compared to flash-induced oxygen yield. The four-step oxidation of the manganese cluster of the WOC was found to be necessary but not sufficient to produce modulation of PSII fluorescence. The capacity of the WOC to generate molecular oxygen was also required to observe a period four in the fluorescence; however, direct quenching by oxygen was not responsible for the modulation. Potential mechanisms responsible for the periodicity of four in both maximum fluorescence yield pattern and flash-dependent changes in proportion of centers with different QA- reoxidation rates are discussed with respect to intrinsic deprotonation events occurring at the WOC. PMID:10451357

  8. A Zn(II)-glycine complex suppresses UVB-induced melanin production by stimulating metallothionein expression.

    PubMed

    Ochiai, Y; Kaburagi, S; Okano, Y; Masaki, H; Ichihashi, M; Funasaka, Y; Sakurai, H

    2008-04-01

    Oxidative stress caused by ultraviolet (UV) radiation generates reactive oxygen species (ROS) in the skin, induces the secretion of melanocyte growth and activating factors from keratinocytes, which results in the formation of cutaneous hyper-pigmentation. Thus, increasing the anti-oxidative ability of skin cells is expected to be a good strategy for skin-lightening cosmetics. Metallothionein (MT) is one of the stress-induced proteins and is known to exhibit a strong anti-oxidative property. We previously reported that a zinc(II) complex with glycine (Zn(II)(Gly)(2)) effectively induces MT expression in cultured human keratinocytes. To determine its potential as a new skin lightening active, we examined whether Zn(II)(Gly)(2) regulates the release of melanocyte-activating factors from UVB-irradiated keratinocytes and affects melanin production in a reconstructed human epidermal equivalent. Conditioned medium from UVB-irradiated keratinocytes accelerated melanocyte proliferation to 110%, and that increase could be prevented by pre-treatment with Zn(II)(Gly)(2). In addition, Zn(II)(Gly)(2) significantly reduced both the production of prostaglandin E(2) and proopiomelanocortin expression in UVB-irradiated keratinocytes. Zn(II)(Gly)(2) also decreased melanin production in a reconstructed human epidermal equivalent. These results indicate that MT-induction in the epidermis effectively up-regulates tolerance against oxidative stress and inhibits the secretion of melanocyte growth and activating factors from keratinocytes. Thus, Zn(II)(Gly)(2) is a good candidate as a new skin-lightening active. PMID:18377619

  9. Disruption of the ribosomal P complex leads to stress-induced autophagy

    PubMed Central

    Artero-Castro, Ana; Perez-Alea, Mileidys; Feliciano, Andrea; Leal, Jose A; Genestar, Mónica; Castellvi, Josep; Peg, Vicente; Ramón y Cajal, Santiago; LLeonart, Matilde E

    2015-01-01

    The human ribosomal P complex, which consists of the acidic ribosomal P proteins RPLP0, RPLP1, and RPLP2 (RPLP proteins), recruits translational factors, facilitating protein synthesis. Recently, we showed that overexpression of RPLP1 immortalizes primary cells and contributes to transformation. Moreover, RPLP proteins are overexpressed in human cancer, with the highest incidence in breast carcinomas. It is thought that disruption of the P complex would directly affect protein synthesis, causing cell growth arrest and eventually apoptosis. Here, we report a distinct mechanism by which cancer cells undergo cell cycle arrest and induced autophagy when RPLP proteins are downregulated. We found that absence of RPLP0, RPLP1, or RPLP2 resulted in reactive oxygen species (ROS) accumulation and MAPK1/ERK2 signaling pathway activation. Moreover, ROS generation led to endoplasmic reticulum (ER) stress that involved the EIF2AK3/PERK-EIF2S1/eIF2α-EIF2S2-EIF2S3-ATF4/ATF-4- and ATF6/ATF-6-dependent arms of the unfolded protein response (UPR). RPLP protein-deficient cells treated with autophagy inhibitors experienced apoptotic cell death as an alternative to autophagy. Strikingly, antioxidant treatment prevented UPR activation and autophagy while restoring the proliferative capacity of these cells. Our results indicate that ROS are a critical signal generated by disruption of the P complex that causes a cellular response that follows a sequential order: first ROS, then ER stress/UPR activation, and finally autophagy. Importantly, inhibition of the first step alone is able to restore the proliferative capacity of the cells, preventing UPR activation and autophagy. Overall, our results support a role for autophagy as a survival mechanism in response to stress due to RPLP protein deficiency. PMID:26176264

  10. Cytokinin delays dark-induced senescence in rice by maintaining the chlorophyll cycle and photosynthetic complexes.

    PubMed

    Talla, Sai Krishna; Panigrahy, Madhusmita; Kappara, Saivishnupriya; Nirosha, P; Neelamraju, Sarla; Ramanan, Rajeshwari

    2016-03-01

    The phytohormone cytokinin (CK) is known to delay senescence in plants. We studied the effect of a CK analog, 6-benzyl adenine (BA), on rice leaves to understand the possible mechanism by which CK delays senescence in a drought- and heat-tolerant rice cultivar Nagina22 (N22) using dark-induced senescence (DIS) as a surrogate for natural senescence of leaves. Leaves of N22-H-dgl162, a stay-green mutant of N22, and BA-treated N22 showed retention of chlorophyll (Chl) pigments, maintenance of the Chl a/b ratio, and delay in reduction of both photochemical efficiency and rate of oxygen evolution during DIS. HPLC analysis showed accumulation of 7-hydroxymethyl chlorophyll (HmChl) during DIS, and the kinetics of its accumulation correlated with progression of senescence. Transcriptome analysis revealed that several plastid-localized genes, specifically those associated with photosystem II (PSII), showed higher transcript levels in BA-treated N22 and the stay-green mutant leaves compared with naturally senescing N22 leaves. Real-time PCR analyses showed that genes coding for enzymes associated with Chl a/b interconversion and proteins associated with light-harvesting complexes maintained higher transcript levels up to 72h of DIS following BA treatment. The pigment-protein complexes analyzed by green gel remained intact in both N22-H-dgl162 and BA-treated N22 leaves even after 96h of DIS. Thus, CK delays senescence by accumulation of HmChl and up-regulating genes in the Chl cycle, thereby maintaining the Chl a/b ratio. Also, CK treatment retains higher transcript levels of PSII-related genes, resulting in the stability of photosynthetic pigment complexes and functional stay-greenness in rice. PMID:26826216

  11. Cytokinin delays dark-induced senescence in rice by maintaining the chlorophyll cycle and photosynthetic complexes

    PubMed Central

    Talla, Sai Krishna; Panigrahy, Madhusmita; Kappara, Saivishnupriya; Nirosha, P; Neelamraju, Sarla; Ramanan, Rajeshwari

    2016-01-01

    The phytohormone cytokinin (CK) is known to delay senescence in plants. We studied the effect of a CK analog, 6-benzyl adenine (BA), on rice leaves to understand the possible mechanism by which CK delays senescence in a drought- and heat-tolerant rice cultivar Nagina22 (N22) using dark-induced senescence (DIS) as a surrogate for natural senescence of leaves. Leaves of N22-H-dgl162, a stay-green mutant of N22, and BA-treated N22 showed retention of chlorophyll (Chl) pigments, maintenance of the Chl a/b ratio, and delay in reduction of both photochemical efficiency and rate of oxygen evolution during DIS. HPLC analysis showed accumulation of 7-hydroxymethyl chlorophyll (HmChl) during DIS, and the kinetics of its accumulation correlated with progression of senescence. Transcriptome analysis revealed that several plastid-localized genes, specifically those associated with photosystem II (PSII), showed higher transcript levels in BA-treated N22 and the stay-green mutant leaves compared with naturally senescing N22 leaves. Real-time PCR analyses showed that genes coding for enzymes associated with Chl a/b interconversion and proteins associated with light-harvesting complexes maintained higher transcript levels up to 72h of DIS following BA treatment. The pigment–protein complexes analyzed by green gel remained intact in both N22-H-dgl162 and BA-treated N22 leaves even after 96h of DIS. Thus, CK delays senescence by accumulation of HmChl and up-regulating genes in the Chl cycle, thereby maintaining the Chl a/b ratio. Also, CK treatment retains higher transcript levels of PSII-related genes, resulting in the stability of photosynthetic pigment complexes and functional stay-greenness in rice. PMID:26826216

  12. Disruption of the ribosomal P complex leads to stress-induced autophagy.

    PubMed

    Artero-Castro, Ana; Perez-Alea, Mileidys; Feliciano, Andrea; Leal, Jose A; Genestar, Mónica; Castellvi, Josep; Peg, Vicente; Ramón Y Cajal, Santiago; Lleonart, Matilde E L

    2015-01-01

    The human ribosomal P complex, which consists of the acidic ribosomal P proteins RPLP0, RPLP1, and RPLP2 (RPLP proteins), recruits translational factors, facilitating protein synthesis. Recently, we showed that overexpression of RPLP1 immortalizes primary cells and contributes to transformation. Moreover, RPLP proteins are overexpressed in human cancer, with the highest incidence in breast carcinomas. It is thought that disruption of the P complex would directly affect protein synthesis, causing cell growth arrest and eventually apoptosis. Here, we report a distinct mechanism by which cancer cells undergo cell cycle arrest and induced autophagy when RPLP proteins are downregulated. We found that absence of RPLP0, RPLP1, or RPLP2 resulted in reactive oxygen species (ROS) accumulation and MAPK1/ERK2 signaling pathway activation. Moreover, ROS generation led to endoplasmic reticulum (ER) stress that involved the EIF2AK3/PERK-EIF2S1/eIF2α-EIF2S2-EIF2S3-ATF4/ATF-4- and ATF6/ATF-6-dependent arms of the unfolded protein response (UPR). RPLP protein-deficient cells treated with autophagy inhibitors experienced apoptotic cell death as an alternative to autophagy. Strikingly, antioxidant treatment prevented UPR activation and autophagy while restoring the proliferative capacity of these cells. Our results indicate that ROS are a critical signal generated by disruption of the P complex that causes a cellular response that follows a sequential order: first ROS, then ER stress/UPR activation, and finally autophagy. Importantly, inhibition of the first step alone is able to restore the proliferative capacity of the cells, preventing UPR activation and autophagy. Overall, our results support a role for autophagy as a survival mechanism in response to stress due to RPLP protein deficiency. PMID:26176264

  13. Infrared laser induced conformational and structural changes of glycine and glycine·water complex in low-temperature matrices

    NASA Astrophysics Data System (ADS)

    Coussan, Stéphane; Tarczay, György

    2016-01-01

    Conformational and structural changes of matrix-isolated glycine and glycine·water complexes induced by the selective MIR excitation of the fundamental OH and NH stretching vibrational modes were studied. The observed spectral changes are consistent with the former assignments based on matrix-isolation IR spectroscopy combined with NIR laser irradiation. Since fewer conformational barriers can be reached by MIR than by NIR excitations, fewer processes are promoted effectively by MIR radiation. The comparison of spectral changes induced by selective MIR and NIR excitations can facilitate the conformational analysis of complex molecular systems and it can also yield information on the barrier heights.

  14. Inducible Repression of Nuclear-Encoded Subunits of the Cytochrome b6f Complex in Tobacco Reveals an Extraordinarily Long Lifetime of the Complex1[W][OPEN

    PubMed Central

    Hojka, Marta; Thiele, Wolfram; Tóth, Szilvia Z.; Lein, Wolfgang; Bock, Ralph; Schöttler, Mark Aurel

    2014-01-01

    The biogenesis of the cytochrome b6f complex in tobacco (Nicotiana tabacum) seems to be restricted to young leaves, suggesting a high lifetime of the complex. To directly determine its lifetime, we employed an ethanol-inducible RNA interference (RNAi) approach targeted against the essential nuclear-encoded Rieske protein (PetC) and the small M subunit (PetM), whose function in higher plants is unknown. Young expanding leaves of both PetM and PetC RNAi transformants bleached rapidly and developed necroses, while mature leaves, whose photosynthetic apparatus was fully assembled before RNAi induction, stayed green. In line with these phenotypes, cytochrome b6f complex accumulation and linear electron transport capacity were strongly repressed in young leaves of both RNAi transformants, showing that the M subunit is as essential for cytochrome b6f complex accumulation as the Rieske protein. In mature leaves, all photosynthetic parameters were indistinguishable from the wild type even after 14 d of induction. As RNAi repression of PetM and PetC was highly efficient in both young and mature leaves, these data indicate a lifetime of the cytochrome b6f complex of at least 1 week. The switch-off of cytochrome b6f complex biogenesis in mature leaves may represent part of the first dedicated step of the leaf senescence program. PMID:24963068

  15. The RNA Helicase DHX34 Activates NMD by Promoting a Transition from the Surveillance to the Decay-Inducing Complex

    PubMed Central

    Hug, Nele; Cáceres, Javier F.

    2014-01-01

    Summary Nonsense-mediated decay (NMD) is a surveillance mechanism that degrades aberrant mRNAs. A complex comprising SMG1, UPF1, and the translation termination factors eRF1 and eRF3 (SURF) is assembled in the vicinity of a premature termination codon. Subsequently, an interaction with UPF2, UPF3b, and the exon junction complex induces the formation of the decay-inducing complex (DECID) and triggers NMD. We previously identified the RNA helicase DHX34 as an NMD factor in C. elegans and in vertebrates. Here, we investigate the mechanism by which DHX34 activates NMD in human cells. We show that DHX34 is recruited to the SURF complex via its preferential interaction with hypophosphorylated UPF1. A series of molecular transitions induced by DHX34 include enhanced recruitment of UPF2, increased UPF1 phosphorylation, and dissociation of eRF3 from UPF1. Thus, DHX34 promotes mRNP remodeling and triggers the conversion from the SURF complex to the DECID complex resulting in NMD activation. PMID:25220460

  16. Daxx cooperates with the Axin/HIPK2/p53 complex to induce cell death.

    PubMed

    Li, Qinxi; Wang, Xuan; Wu, Xiaoling; Rui, Yanning; Liu, Wei; Wang, Jifeng; Wang, Xinghao; Liou, Yih-Cherng; Ye, Zhiyun; Lin, Sheng-Cai

    2007-01-01

    Daxx, a death domain-associated protein, has been implicated in proapoptosis, antiapoptosis, and transcriptional regulation. Many factors known to play critically important roles in controlling apoptosis and gene transcription have been shown to associate with Daxx, including the Ser/Thr protein kinase HIPK2, promyelocytic leukemia protein, histone deacetylases, and the chromatin remodeling protein ATRX. Although it is clear that Daxx may exert multiple functions, the underlying mechanisms remain far from clear. Here, we show that Axin, originally identified for its scaffolding role to control beta-catenin levels in Wnt signaling, strongly associates with Daxx at endogenous levels. The Daxx/Axin complex formation is enhanced by UV irradiation. Axin tethers Daxx to the tumor suppressor p53, and cooperates with Daxx, but not DaxxDeltaAxin, which is unable to interact with Axin, to stimulate HIPK2-mediated Ser(46) phosphorylation and transcriptional activity of p53. Interestingly, Axin and Daxx seem to selectively activate p53 target genes, with strong activation of PUMA, but not p21 or Bax. Daxx-stimulated p53 transcriptional activity was significantly diminished by small interfering RNA against Axin; Daxx fails to inhibit colony formation in Axin(-/-) cells. Moreover, UV-induced cell death was attenuated by the knockdown of Axin and Daxx. All these results show that Daxx cooperates with Axin to stimulate p53, and implicate a direct role for Axin, HIPK2, and p53 in the proapoptotic function of Daxx. We have hence unraveled a novel aspect of p53 activation and shed new light on the ultimate understanding of the Daxx protein, perhaps most pertinently, in relation to stress-induced cell death. PMID:17210684

  17. On the origins of large interaction-induced first hyperpolarizabilities in hydrogen-bonded π-electronic complexes.

    PubMed

    Góra, Robert W; Błasiak, Bartosz

    2013-08-01

    In this article we elucidate the origins of interaction-induced linear and nonlinear electro-optic properties of model hydrogen-bonded π-electronic complexes. In particular we report on contributions due to various interaction energy terms to excess dipole moments (Δμ), electric dipole polarizabilities (Δα), and first hyperpolarizabilities (Δβ), focusing on the latter. The analysis of intermolecular interaction-induced electric properties is performed for selected model systems including quasi-linear dimers of urea, diformamide, 4-pyridone, 4-nitroaniline, and the complex of hydrogen fluoride with nitroacetylene. The nature of intermolecular interactions as well as of the Δμ and Δα is very similar in all studied complexes. However, partitioning of Δβ into physically well-defined components reveals that the origins of this term, the magnitude of which is often comparable to the hyperpolarizabilities of isolated monomers, are different in each case. Our results indicate that, even though hydrogen bonding usually diminishes the nonlinear response of interacting species, the first hyperpolarizability of complexes with the nitro group acting as a proton acceptor is substantially increased, essentially due to field-induced changes of electrostatic interactions between subsystems. However, in the remaining complexes the origins of Δβ are much more involved. Even though at large intermolecular separations the origins of interaction-induced electric properties are essentially due to the field-induced electrostatic and induction interactions, in the vicinity of van der Waals minimum the overlap effects cannot be neglected since they may substantially alter the predicted excess properties or even determine their magnitude and sign. On the other hand the Δβ contribution due to dispersion interactions is usually negligible. Interestingly, the values of interaction-induced first hyperpolarizability in some cases depend strongly on the intermolecular separation

  18. Changes of conductance and compressibility of bilayer lipid membranes induced by oligonucleotide-cationic polyene antibiotic complexes.

    PubMed

    Hianik, Tibor; Ostatnik, Lukas; Polohova, Vladimira; Bolard, Jacques

    2008-11-01

    The positively charged polyene molecule amphotericin B 3-dimethylaminopropylamide (AMA) is an efficient agent for the delivery of antisense oligodeoxyribonucleotides (ODN) into target cells. In the present study, bilayer lipid membrane (BLM) conductance, elasticity modulus perpendicular to the membrane plane, surface potential and electrical capacitance were measured by conductance and electrostriction methods in the presence of AMA, pure or complexed to 20-mer single stranded ODN at different ratios. Pure AMA did not induce changes in conductance of cholesterol-containing BLM, but did induce an increase in elasticity modulus and surface potential. ODN/AMA complexes changed BLM properties depending on the charge ratio. The most pronounced effect on membrane conductance was observed for positively charged ODN/AMA complexes (charge ratio rho-/+=0.1), while for negatively charged complexes these changes were less marked/apparent, correlating to substantially lower binding constants. The effect of ODN/AMA complexes on elasticity modulus and charge potential was biphasic. After an increase in both values, a decrease was observed for higher incubation times and ODN/AMA concentrations. These results are interpreted as indicating that the membrane property changes result from the large AMA aggregates induced by the presence of the negatively charged ODN, which condensate on these aggregates. It is suggested that the decrease of elasticity modulus and surface potential in the presence of increasing incubation time and AMA concentration result from desorption of the complexes in the complex-free compartment of the BLM cell, or appearance of a non-linear conductance of the lipid bilayer. The first alternative would explain the AMA-induced transmembrane transfer of ODN. PMID:17904427

  19. Multiple Analogies for Complex Concepts: Antidotes for Analogy-Induced Misconception in Advanced Knowledge Acquisition. Technical Report No. 439.

    ERIC Educational Resources Information Center

    Spiro, Rand J.; And Others

    This report argues that there exists a pervasive tendency for analogies to contribute to the development of entrenched misconceptions in the form of reducing complex new knowledge to the core of a source analogy. The report presents a taxonomy of ways that simple analogy induces conceptual error and an alternative approach involving integrated…

  20. Genetic factors influence level of proteinuria in cationic antigen-induced immune complex glomerulonephritis in the rat.

    PubMed Central

    Kato, A; Thaiss, F; Oite, T; Günther, E; Batsford, S; Vogt, A

    1985-01-01

    The influence of genetic factors on the susceptibility of the rat to cationic antigen-induced in situ immune complex glomerulonephritis was investigated. The levels of proteinuria developing in 11 inbred strains of rats differing in MHC and in genetic background varied markedly. Susceptibility was not MHC associated but resided in the genetic background. PMID:3159528

  1. Depolarization-induced release of amino acids from the vestibular nuclear complex.

    PubMed

    Godfrey, Donald A; Sun, Yizhe; Frisch, Christopher; Godfrey, Matthew A; Rubin, Allan M

    2012-04-01

    There is evidence from immunohistochemistry, quantitative microchemistry, and pharmacology for several amino acids as neurotransmitters in the vestibular nuclear complex (VNC), including glutamate, γ-aminobutyrate (GABA), and glycine. However, evidence from measurements of release has been limited. The purpose of this study was to measure depolarization-stimulated calcium-dependent release of amino acids from the VNC in brain slices. Coronal slices containing predominantly the VNC were prepared from rats and perfused with artificial cerebrospinal fluid (ACSF) in an interface chamber. Fluid was collected from the chamber just downstream from the VNC using a microsiphon. Depolarization was induced by 50 mM potassium in either control calcium and magnesium concentrations or reduced calcium and elevated magnesium. Amino acid concentrations in effluent fluid were measured by high performance liquid chromatography. Glutamate release increased fivefold during depolarization in control calcium concentration and twofold in low calcium/high magnesium. These same ratios were 6 and 1.5 for GABA, 2 and 1.3 for glycine, and 2 and 1.5 for aspartate. Differences between release in control and low calcium/high magnesium ACSF were statistically significant for glutamate, GABA, and glycine. Glutamine release decreased during and after depolarization, and taurine release slowly increased. No evidence for calcium-dependent release was found for serine, glutamine, alanine, threonine, arginine, taurine, or tyrosine. Our results support glutamate and GABA as major neurotransmitters in the VNC. They also support glycine as a neurotransmitter and some function for taurine. PMID:22147284

  2. An Interfacial Europium Complex on SiO2 Nanoparticles: Reduction-Induced Blue Emission System

    NASA Astrophysics Data System (ADS)

    Ishii, Ayumi; Hasegawa, Miki

    2015-06-01

    In this study, Eu-coated SiO2 nanoparticles have been prepared, consisting of an interfacial complex of Eu and 1,10-phenanthroline (phen) at the solid surfaces of the SiO2/Eu nanostructures. The as-prepared SiO2/Eu/phen nanoparticles exhibits sharp red emission via energy transfer from the phen to the EuIII. After sintering at 200 °C in air, the emission is tuned from red to blue. The blue emission is originated from EuII. This reduction-induced emissive phenomenon resulted from the electron-donating environment created by the surrounding phen and SiO2, which is the first reported fabrication of a stable EuII-based emissive material using mild conditions (reaction in air and at low temperature) and an organic-inorganic hybrid nanostructure. The existence of two different stable oxidation states with characteristic emissions, blue emissive EuII and red emissive EuIII, suggests significant potential applications as novel luminescent materials with inorganic-organic hybrid structures.

  3. In vitro assembly of plant RNA-induced silencing complexes facilitated by molecular chaperone HSP90.

    PubMed

    Iki, Taichiro; Yoshikawa, Manabu; Nishikiori, Masaki; Jaudal, Mauren C; Matsumoto-Yokoyama, Eiko; Mitsuhara, Ichiro; Meshi, Tetsuo; Ishikawa, Masayuki

    2010-07-30

    RNA-induced silencing complexes (RISCs) play central roles in posttranscriptional gene silencing. In plants, the mechanism of RISC assembly has remained elusive due to the lack of cell-free systems that recapitulate the process. In this report, we demonstrate that plant AGO1 protein synthesized by in vitro translation using an extract of evacuolated tobacco protoplasts incorporates synthetic small interfering RNA (siRNA) and microRNA (miRNA) duplexes to form RISCs that sequester the single-stranded siRNA guide strand and miRNA strand, respectively. The formed RISCs were able to recognize and cleave the complementary target RNAs. In this system, the siRNA duplex was incorporated into HSP90-bound AGO1, and subsequent removal of the passenger strand was triggered by ATP hydrolysis by HSP90. Removal of the siRNA passenger strand required the ribonuclease activity of AGO1, while that of the miRNA star strand did not. Based on these results, the mechanism of plant RISC formation is discussed. PMID:20605502

  4. Laser-induced periodic surface structures of thin, complex multi-component films

    NASA Astrophysics Data System (ADS)

    Reif, Juergen; Varlamova, Olga; Ratzke, Markus; Uhlig, Sebastian

    2016-04-01

    Femtosecond laser-induced regular nanostructures are generated on a complex multilayer target, namely a piece of a commercial, used hard disk memory. It is shown that after single-shot 800-nm irradiation at 0.26 J/cm2 only the polymer cover layer and—in the center—a portion of the magnetic multilayer are ablated. A regular array of linearly aligned spherical 450-nm features at the uncovered interface between cover and magnetic layers appears not to be produced by the irradiation. Only after about 10 pulses on one spot, classical ripples perpendicular to the laser polarization with a period of ≈700 nm are observed, with a modulation between 40 nm above and 40 nm below the pristine surface and an ablation depth only slightly larger than the thickness of the multilayer magnetic film. Further increase of the pulse number does not result in deeper ablation. However, 770-nm ripples become parallel to the polarization and are swelling to more than 120 nm above zero, much more than the full multilayer film thickness. In the spot periphery, much shallower 300-nm ripples are perpendicular to the strong modulation and the laser polarization. Irradiation with 0.49-J/cm2 pulses from an ultrafast white-light continuum results—in the spot periphery—in the formation of 200-nm ripples, only swelling above zero after removal of the polymer cover, without digging into the magnetic film.

  5. An Interfacial Europium Complex on SiO2 Nanoparticles: Reduction-Induced Blue Emission System

    PubMed Central

    Ishii, Ayumi; Hasegawa, Miki

    2015-01-01

    In this study, Eu-coated SiO2 nanoparticles have been prepared, consisting of an interfacial complex of Eu and 1,10-phenanthroline (phen) at the solid surfaces of the SiO2/Eu nanostructures. The as-prepared SiO2/Eu/phen nanoparticles exhibits sharp red emission via energy transfer from the phen to the EuIII. After sintering at 200 °C in air, the emission is tuned from red to blue. The blue emission is originated from EuII. This reduction-induced emissive phenomenon resulted from the electron-donating environment created by the surrounding phen and SiO2, which is the first reported fabrication of a stable EuII-based emissive material using mild conditions (reaction in air and at low temperature) and an organic-inorganic hybrid nanostructure. The existence of two different stable oxidation states with characteristic emissions, blue emissive EuII and red emissive EuIII, suggests significant potential applications as novel luminescent materials with inorganic-organic hybrid structures. PMID:26122318

  6. Videogame training strategy-induced change in brain function during a complex visuomotor task.

    PubMed

    Lee, Hyunkyu; Voss, Michelle W; Prakash, Ruchika Shaurya; Boot, Walter R; Vo, Loan T K; Basak, Chandramallika; Vanpatter, Matt; Gratton, Gabriele; Fabiani, Monica; Kramer, Arthur F

    2012-07-01

    Although changes in brain function induced by cognitive training have been examined, functional plasticity associated with specific training strategies is still relatively unexplored. In this study, we examined changes in brain function during a complex visuomotor task following training using the Space Fortress video game. To assess brain function, participants completed functional magnetic resonance imaging (fMRI) before and after 30 h of training with one of two training regimens: Hybrid Variable-Priority Training (HVT), with a focus on improving specific skills and managing task priority, or Full Emphasis Training (FET), in which participants simply practiced the game to obtain the highest overall score. Control participants received only 6 h of FET. Compared to FET, HVT learners reached higher performance on the game and showed less brain activation in areas related to visuo-spatial attention and goal-directed movement after training. Compared to the control group, HVT exhibited less brain activation in right dorsolateral prefrontal cortex (DLPFC), coupled with greater performance improvement. Region-of-interest analysis revealed that the reduction in brain activation was correlated with improved performance on the task. This study sheds light on the neurobiological mechanisms of improved learning from directed training (HVT) over non-directed training (FET), which is related to visuo-spatial attention and goal-directed motor planning, while separating the practice-based benefit, which is related to executive control and rule management. PMID:22504276

  7. Effects on mitochondria of mitochondria-induced nitric oxide release from a ruthenium nitrosyl complex.

    PubMed

    Pestana, Cezar R; Phelippin, Daniela P S; Polizello, Ana C M; Dorta, Daniel J; Uyemura, Sergio A; Santos, Antonio C; Doro, Fábio G; Rodrigues, Fernando P; Tfouni, Elia; Curti, Carlos

    2009-02-01

    The ruthenium nitrosyl complex trans-[Ru(NO)(NH(3))(4)(py)](PF(6))(3) (pyNO), a nitric oxide (NO) donor, was studied in regard to the release of NO and its impact both on isolated mitochondria and HepG2 cells. In isolated mitochondria, NO release from pyNO was concomitant with NAD(P)H oxidation and, in the 25-100 microM range, it resulted in dissipation of mitochondrial membrane potential, inhibition of state 3 respiration, ATP depletion and reactive oxygen species (ROS) generation. In the presence of Ca(2+), mitochondrial permeability transition (MPT), an unspecific membrane permeabilization involved in cell necrosis and some types of apoptosis, was elicited. As demonstrated by externalization of phosphatidylserine and activation of caspase-9 and caspase-3, pyNO (50-100 microM) induced HepG2 cell death, mainly by apoptosis. The combined action of the NO itself, the peroxynitrite yielded by NO in the presence of reactive oxygen species (ROS) and the oxidative stress generated by the NAD(P)H oxidation is proposed to be involved in cell death by pyNO, both via respiratory chain inhibition and ROS levels increase, or even via MPT, if Ca(2+) is present. PMID:18950724

  8. Turbulent secondary flows in high Reynolds number boundary layers induced by streamwise-elongated complex roughness

    NASA Astrophysics Data System (ADS)

    Anderson, William; Barros, Julio; Christensen, Kenneth

    2014-11-01

    It has been reported that complex roughness with a predominant streamwise elongation induces secondary mean flow heterogeneities in the above turbulent boundary layer (Mejia-Alvarez and Christensen, Phys. Fluids 25, 115 (2013), MAC; Nugroho et al., Int. J. Heat Fluid Flow 41, 90 (2013)). These mean secondary flows exist as transverse variations of mean streamwise velocity (so-called low- and high-momentum pathways, MAC) and are flanked by mean counter-rotating, boundary layer-scale circulations (Christensen and Barros, J. Fluid Mech. 748, R1 (2014)). In related work, we have used large-eddy simulation to model turbulent boundary layer flow over a suite of topographies composed of ``strips'' of high and low roughness length (drag imposed with the equilibrium logarithmic law); in all cases, we observe the formation of high- and low-momentum pathways (Willingham et al., Phys. Fluids 26, 025111 (2013)). Here, we investigate turbulence statistics from large-eddy simulation such as magnitudes and spatial gradients of Reynolds stresses and turbulence kinetic energy, to discern underlying physical processes responsible for the secondary flows. We demonstrate that elevated production of turbulence above ``high'' roughness necessitates the mean circulations by virtue of turbulent kinetic energy production-dissipation non-equilibrium. We propose that the mean flow is Prandtl's secondary flow of the second kind.

  9. Ionic Charge Transfer Complex Induced Visible Light Harvesting and Photocharge Generation in Perovskite.

    PubMed

    Ng, Tsz-Wai; Thachoth Chandran, Hrisheekesh; Chan, Chiu-Yee; Lo, Ming-Fai; Lee, Chun-Sing

    2015-09-16

    Organometal trihalide perovskite has recently emerged as a new class of promising material for high efficiency solar cells applications. While excess ions in perovskites are recently getting a great deal of attention, there is so far no clear understanding on both their formation and relating ions interaction to the photocharge generation in perovskite. Herein, we showed that tremendous ions indeed form during the initial stage of perovskite formation when the organic methylammonium halide (MAXa, Xa=Br and I) meets the inorganic PbXb2 (Xb=Cl, Br, I). The strong charge exchanges between the Pb2+ cations and Xa- anions result in formation of ionic charge transfer complexes (iCTC). MAXa parties induce empty valence electronic states within the forbidden bandgap of PbXb2. The strong surface dipole provide sufficient driving force for sub-bandgap electron transition with energy identical to the optical bandgap of forming perovskites. Evidences from XPS/UPS and photoluminescence studies showed that the light absorption, exciton dissociation, and photocharge generation of the perovskites are closely related to the strong ionic charge transfer interactions between Pb2+ and Xa- ions in the perovskite lattices. Our results shed light on mechanisms of light harvesting and subsequent free carrier generation in perovskites. PMID:26305717

  10. Benzaldehyde Thiosemicarbazone Derived from Limonene Complexed with Copper Induced Mitochondrial Dysfunction in Leishmania amazonensis

    PubMed Central

    Britta, Elizandra Aparecida; Barbosa Silva, Ana Paula; Ueda-Nakamura, Tânia; Dias-Filho, Benedito Prado; Silva, Cleuza Conceição; Sernaglia, Rosana Lázara; Nakamura, Celso Vataru

    2012-01-01

    Background Leishmaniasis is a major health problem that affects more than 12 million people. Treatment presents several problems, including high toxicity and many adverse effects, leading to the discontinuation of treatment and emergence of resistant strains. Methodology/Principal Findings We evaluated the in vitro antileishmanial activity of benzaldehyde thiosemicarbazone derived from limonene complexed with copper, termed BenzCo, against Leishmania amazonensis. BenzCo inhibited the growth of the promastigote and axenic amastigote forms, with IC50 concentrations of 3.8 and 9.5 µM, respectively, with 72 h of incubation. Intracellular amastigotes were inhibited by the compound, with an IC50 of 10.7 µM. BenzCo altered the shape, size, and ultrastructure of the parasites. Mitochondrial membrane depolarization was observed in protozoa treated with BenzCo but caused no alterations in the plasma membrane. Additionally, BenzCo induced lipoperoxidation and the production of mitochondrial superoxide anion radicals in promastigotes and axenic amastigotes of Leishmania amazonensis. Conclusion/Significance Our studies indicated that the antileishmania activity of BenzCo might be associated with mitochondrial dysfunction and oxidative damage, leading to parasite death. PMID:22870222

  11. Fabrication and characterization of poly(L-lactic acid) gels induced by fibrous complex crystallization with solvents

    SciTech Connect

    Matsuda, Yasuhiro; Fukatsu, Akinobu; Wang, Yangyang; Miyamoto, Kazuaki; Mays, Jimmy; Tasaka, Shigeru

    2014-01-01

    Complex crystal induced gelation of poly(L-lactic acid) (PLLA) solutions was studied for a series of solvents, including N,N-dimethylformamide (DMF). By cooling the solutions prepared at elevated temperatures, PLLA gels were produced in solvents that induced complex crystals ( -crystals) with PLLA. Fibrous structure of PLLA in the gel with DMF was observed by polarizing optical microscopy, field emission electron microscopy, and atomic force microscopy. Upon heating, the crystal form of PLLA in the DMF gel changed from -crystal to a-crystal, the major crystal form in common untreated PLLA films, but the morphology and high elastic modulus of the gel remained until the a-crystal dissolved at higher temperature. In addition, a solvent exchanging method was developed, which allowed PLLA gels to be prepared in other useful solvents that do not induce -crystals without losing the morphology and mechanical properties.

  12. A label-free kissing complexes-induced fluorescence aptasensor using DNA-templated silver nanoclusters as a signal transducer.

    PubMed

    Zhang, Kai; Wang, Ke; Zhu, Xue; Xie, Minhao

    2016-04-15

    Riboswitches are complex folded RNA domains that serve as receptors for specific metabolites which identified in prokaryotes. They are comprised of a biosensor that includes the binding site for a small ligand and they respond to association with this ligand by undergoing a conformational change. In the present study, we report on the integration of silver nanoclusters (AgNCs) and riboswitches for the development of a kissing complexes-induced aptasensor (KCIA). We specifically apply the tunable riboswitches properties of this strategy to demonstrate the multiplexes analysis of adenosine and adenosine deaminase (ADA). This strategy allows for simple tethering of the specific oligonucleotides stabilizing the AgNCs to the nucleic acid probes. This is a new concept for aptasensors, and opens an opportunity for design of more novel biosensors based on the kissing complexes-induced strategy. PMID:26606306

  13. Complex Interplay between HIV-1 Capsid and MX2-Independent Alpha Interferon-Induced Antiviral Factors

    PubMed Central

    Bulli, Lorenzo; Apolonia, Luis; Kutzner, Juliane; Pollpeter, Darja; Goujon, Caroline; Herold, Nikolas; Schwarz, Sarah-Marie; Giernat, Yannick; Keppler, Oliver T.

    2016-01-01

    limit HIV-1 replication by inducing the expression of a set of antiviral genes that inhibit HIV-1 at multiple steps in its life cycle, including the postentry steps of reverse transcription and nuclear import. This is observed in cultured cell systems, as well as in clinical trials in HIV-1-infected patients. The identities of the cellular antiviral factors, their viral targets, and the underpinning mechanisms are largely unknown. We show here that the HIV-1 Capsid protein plays a central role in protecting the virus from IFN-induced inhibitors that block early postentry steps of infection. We further show that host cell cyclophilins play an important role in regulating these processes, thus highlighting the complex interplay between antiviral effector mechanisms and viral survival. PMID:27279606

  14. Association between GABAA Receptor Subunit Gene Cluster and Zolpidem-Induced Complex Sleep Behaviors in Han Chinese

    PubMed Central

    Tsai, Jui-Hsiu; Yang, Pinchen; Lin, Hung-Hsun; Cheng, Kuang-hung; Yang, Yi-Hsin; Wu, Ming-Tsang; Chen, Cheng-Chung

    2013-01-01

    Study Objectives: To investigate and elucidate the role of GABAA receptor subunits, specifically the 2 genetic markers at the GABAA α1 and GABAA α6 receptors, in zolpidem-induced complex sleep behaviors (CSBs). Design: Genetic association study. Setting: Kaohsiung Medical University-affiliated hospitals, Kaohsiung, Taiwan. Patients: 30 zolpidem-induced CSB subjects and 37 controls. Interventions: N/A. Measurements and Results: The χ2 test demonstrated an association between the A15G variant at the GABAA α1 receptor subunit gene and zolpidem-induced CSBs (P = 0.007). The adjusted odds ratio of the GABAA α1 receptor subunit genotype for the risk of zolpidem-induced CSBs was approximately 10 (OR = 9.99, 95% CI = 1.82, 74.87; P = 0.013). Conclusions: The finding reveals that the A15G variant at the GABAA α1 receptor subunit gene confers a high risk of zolpidem-induced CSBs and may be considered in clinical services. Citation: Tsai JH; Yang P; Lin HH; Cheng Kh; Yang YH; Wu MT; Chen CC. Association between GABAA receptor subunit gene cluster and zolpidem-induced complex sleep behaviors in Han Chinese. SLEEP 2013;36(2):197–202. PMID:23372267

  15. Zinc Induces Dimerization of the Class II Major Histocompatibility Complex Molecule That Leads to Cooperative Binding to a Superantigen

    SciTech Connect

    Li,H.; Zhao, Y.; Guo, Y.; Li, Z.; Eislele, L.; Mourad, W.

    2007-01-01

    Dimerization of class II major histocompatibility complex (MHC) plays an important role in the MHC biological function. Mycoplasma arthritidis-derived mitogen (MAM) is a superantigen that can activate large fractions of T cells bearing specific T cell receptor V{beta} elements. Here we have used structural, sedimentation, and surface plasmon resonance detection approaches to investigate the molecular interactions between MAM and the class II MHC molecule HLA-DR1 in the context of a hemagglutinin peptide-(306-318) (HA). Our results revealed that zinc ion can efficiently induce the dimerization of the HLA-DR1/HA complex. Because the crystal structure of the MAM/HLA-DR1/hemagglutinin complex in the presence of EDTA is nearly identical to the structure of the complex crystallized in the presence of zinc ion, Zn{sup 2+} is evidently not directly involved in the binding between MAM and HLA-DR1. Sedimentation and surface plasmon resonance studies further revealed that MAM binds the HLA-DR1/HA complex with high affinity in a 1:1 stoichiometry, in the absence of Zn{sup 2+}. However, in the presence of Zn{sup 2+}, a dimerized MAM/HLA-DR1/HA complex can arise through the Zn{sup 2+}-induced DR1 dimer. In the presence of Zn{sup 2+}, cooperative binding of MAM to the DR1 dimer was also observed.

  16. PET imaging of ischemia-induced impairment of mitochondrial complex I function in monkey brain

    PubMed Central

    Tsukada, Hideo; Ohba, Hiroyuki; Nishiyama, Shingo; Kanazawa, Masakatsu; Kakiuchi, Takeharu; Harada, Norihiro

    2014-01-01

    To assess the capability of 18F-2-tert-butyl-4-chloro-5-{6-[2-(2-fluoroethoxy)-ethoxy]-pyridin-3-ylmethoxy}-2H-pyridazin-3-one (18F-BCPP-EF), a novel positron emission tomography (PET) probe for mitochondrial complex I (MC-I) activity, as a specific marker of ischemia-induced neuronal death without being disturbed by inflammation, translational research was conducted using an animal PET in ischemic brains of Cynomolgus monkeys (Macaca fascicularis). Focal ischemia was induced by the right middle cerebral artery occlusion for 3 hours, then PET scans were conducted at Day-7 with 15O-gases for regional cerebral blood flow (rCBF) and regional cerebral metabolism of oxygen (rCMRO2), and 18F-BCPP-EF for MC-I with arterial blood sampling. On Day-8, the additional PET scans conducted with 11C-flumazenil (11C-FMZ) for central-type benzodiazepine receptors, 11C-PBR28 for translocator protein, and 18F-fluoro-2-deoxy-D-glucose (18F-FDG) for regional cerebral metabolic rate of glucose (rCMRglc). The total distribution volume (VT) values of 18F-BCPP-EF showed the significant reduction in MC-I activity in the damaged area at Day-7. When correlated with rCBF and rCMRO2, the VT values of 18F-BCPP-EF provided better correlation with rCMRO2 than with rCBF. In the inflammatory regions (region of interest, ROIPBR) of the ischemic hemisphere detected with 11C-PBR28, higher 18F-FDG uptake and lower VT of 18F-BCPP-EF, 11C-FMZ, and rCMRO2 than those in normal contralateral hemisphere were observed. These results strongly suggested that 18F-BCPP-EF could discriminate the neuronal damaged areas with neuroinflammation, where 18F-FDG could not owing to its high uptake into the activated microglia. PMID:24447952

  17. TD-DFT study of the light-induced spin crossover of Fe(III) complexes.

    PubMed

    Saureu, Sergi; de Graaf, Coen

    2016-01-14

    Two light-induced spin-crossover Fe(III) compounds have been studied with time-dependent density functional theory (TD-DFT) to investigate the deactivation mechanism and the role of the ligand-field states as intermediates in this process. The B3LYP* functional has previously shown its ability to accurately describe (light-induced) spin-crossover in Fe(II) complexes. Here, we establish its performance for Fe(III) systems using [Fe(qsal)2](+) (Hqsal = 2-[(8-quinolinylimino)methyl]phenol) and [Fe(pap)2](+) (Hpap = 2-(2-pyridylmethyleneamino)phenol) as test cases comparing the B3LYP* results to experimental information and to multiconfigurational wave function results. In addition to rather accurate high spin (HS) and low spin (LS) state geometries, B3LYP* also predicts ligand-to-metal charge transfer (LMCT) states with large oscillator strength in the energy range where the UV-VIS spectrum shows an intense absorption band, whereas optically allowed π-π* excitations on the ligands were calculated at higher energy. Subsequently, we have generated a two-dimensional potential energy surface of the HS and LS states varying the Fe-N and Fe-O distances. LMCT and metal centered (MC) excited states were followed along the approximate minimal energy path that connects the minima of the HS and LS on this surface. The (2)LMCT state has a minimum in the same region as the initial LS state, where we also observe a crossing with the intermediate spin (IS) state. Upon the expansion of the coordination sphere of the Fe(III) ion, the IS state crosses with the HS state and further expansion of the coordination sphere leads to the excited spin state trapping as observed in experiment. The calculation of the intersystem crossing rates reveals that the deactivation from (2)LMCT → IS → HS competes with the (2)LMCT → IS → LS pathway, in line with the low efficiency encountered in experiments. PMID:26660866

  18. Design and characterization of a novel lipid-DNA complex that resists serum-induced destabilization.

    PubMed

    Lian, Tianshun; Ho, Rodney J Y

    2003-12-01

    Ineffectiveness of cationic lipids to enhance DNA transfection has been attributed to serum-mediated dissociation and perhaps complement activation of lipid-DNA complexes. To overcome these problems, we have developed a novel lipid-DNA complex that greatly reduces serum-mediated dissociation. The complexes were prepared by mixing cationic liposomes containing 1,2-dioleoyl-3-trimethylammonium-propane and dioleoylphosphatidyl-ethanolamine and DNA in ethanolic (20% v/v ethanol) solution containing 5% sucrose followed by dehydration via rotating evaporation. Upon hydration in H(2)O, the lipid-DNA complexes [ethanol-dried lipid-DNA (EDL) complexes] were formed. The complexes exhibit a low positive zeta potential and enhanced transfection efficiency in contrast to the suppressed efficiency detected with admixed lipid-DNA complexes in the presence of serum across several cell lines. This result may be attributed to the inability of serum to dissociate DNA from lipids in EDL complexes. Using displacement of ethidium bromide intercalation analysis, we found that in serum, only 50% of DNA was exposed in the EDL complexes, compared with 100% in the admixed lipid-DNA complexes. The EDL complexes also showed increased resistance to DNase digestion in the presence of negatively charged lipid, while reducing complement activation in serum. The EDL complexes may improve the transfection activity of lipid-DNA complexes in serum and, perhaps, in vivo. PMID:14603483

  19. Light induced catalytic intramolecular hydrofunctionalization of allylphenols mediated by porphyrin rhodium(iii) complexes.

    PubMed

    Liu, Xu; Wang, Zikuan; Fu, Xuefeng

    2016-09-14

    Catalytic intramolecular hydrofunctionalization of allylphenols to heterocyclic compounds mediated by rhodium(iii) porphyrin complexes was described. The Wacker-type intermediate β-heterocyclic alkyl rhodium complex was independently synthesized and crystallized. PMID:27482840

  20. Plant host and sugar alcohol induced exopolysaccharide biosynthesis in the Burkholderia cepacia complex.

    PubMed

    Bartholdson, S Josefin; Brown, Alan R; Mewburn, Ben R; Clarke, David J; Fry, Stephen C; Campopiano, Dominic J; Govan, John R W

    2008-08-01

    The species that presently constitute the Burkholderia cepacia complex (Bcc) have multiple roles; they include soil and water saprophytes, bioremediators, and plant, animal and human pathogens. Since the first description of pathogenicity in the Bcc was based on sour skin rot of onion bulbs, this study returned to this plant host to investigate the onion-associated phenotype of the Bcc. Many Bcc isolates, which were previously considered to be non-mucoid, produced copious amounts of exopolysaccharide (EPS) when onion tissue was provided as the sole nutrient. EPS production was not species-specific, was observed in isolates from both clinical and environmental sources, and did not correlate with the ability to cause maceration of onion tissue. Chemical analysis suggested that the onion components responsible for EPS induction were primarily the carbohydrates sucrose, fructose and fructans. Additional sugars were investigated, and all alcohol sugars tested were able to induce EPS production, in particular mannitol and glucitol. To investigate the molecular basis for EPS biosynthesis, we focused on the highly conserved bce gene cluster thought to be involved in cepacian biosynthesis. We demonstrated induction of the bce gene cluster by mannitol, and found a clear correlation between the inability of representatives of the Burkholderia cenocepacia ET12 lineage to produce EPS and the presence of an 11 bp deletion within the bceB gene, which encodes a glycosyltransferase. Insertional inactivation of bceB in Burkholderia ambifaria AMMD results in loss of EPS production on sugar alcohol media. These novel and surprising insights into EPS biosynthesis highlight the metabolic potential of the Bcc and show that a potential virulence factor may not be detected by routine laboratory culture. Our results also highlight a potential hazard in the use of inhaled mannitol as an osmolyte to improve mucociliary clearance in individuals with cystic fibrosis. PMID:18667584

  1. Increased RNA-Induced Silencing Complex (RISC) Activity Contributes to Hepatocellular Carcinoma

    PubMed Central

    Yoo, Byoung Kwon; Santhekadur, Prasanna K.; Gredler, Rachel; Chen, Dong; Emdad, Luni; Bhutia, Sujit; Pannell, Lewis; Fisher, Paul B.; Sarkar, Devanand

    2011-01-01

    There is virtually no effective treatment for advanced hepatocellular carcinoma (HCC) and novel targets need to be identified to develop effective treatment. We recently documented that the oncogene Astrocyte elevated gene-1 (AEG-1) plays a seminal role in hepatocarcinogenesis. Employing yeast two-hybrid assay and co-immunoprecipitation followed by mass spectrometry we identified Staphylococcal nuclease domain containing 1 (SND1), a nuclease in the RNA-induced silencing complex (RISC) facilitating RNAi-mediated gene silencing, as an AEG-1 interacting protein. Co-immunoprecipitation and co-localization studies confirmed that AEG-1 is also a component of RISC and both AEG-1 and SND1 are required for optimum RISC activity facilitating siRNA and miRNA-mediated silencing of luciferase reporter gene. In 109 human HCC samples SND1 was overexpressed in ∼74% cases compared to normal liver. Correspondingly, significantly higher RISC activity was observed in human HCC cells compared to immortal normal hepatocytes. Increased RISC activity, conferred by AEG-1 or SND1, resulted in increased degradation of tumor suppressor mRNAs that are target of oncomiRs. Inhibition of enzymatic activity of SND1 significantly inhibited proliferation of human HCC cells. As a corollary, stable overexpression of SND1 augmented and siRNA-mediated inhibition of SND1 abrogated growth of human HCC cells in vitro and in vivo thus revealing a potential role of SND1 in hepatocarcinogenesis. Conclusion We unravel a novel mechanism that overexpression of AEG-1 and SND1 leading to increased RISC activity might contribute to hepatocarcinogenesis. Targeted inhibition of SND1 enzymatic activity might be developed as an effective therapy for HCC. PMID:21520169

  2. Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow.

    PubMed

    Katsuyama, Narumi; Usui, Nobuo; Taira, Masato

    2016-01-01

    A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity. PMID:27597999

  3. Light-induced excited spin state trapping and charge transfer in trigonal bipyramidal cyanide-bridged complexes.

    PubMed

    Funck, Kristen E; Prosvirin, Andrey V; Mathonière, Corine; Clérac, Rodolphe; Dunbar, Kim R

    2011-04-01

    Three members of the family of trigonal bipyramidal (TBP) complexes of general formula [M(tmphen)(2)](3)[M'(CN)(6)](2) (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline) or [M(3)M'(2)], which are known to exhibit thermally induced spin crossover and charge transfer, have been investigated for optical and photomagnetic properties. The light-induced excited spin-state trapping (LIESST) effect found in classical spin crossover compounds, such as [Fe(phen)(2)(NCS)(2)], was explored for the [Fe(3)Fe(2)] and [Fe(3)Co(2)] compounds. Similarly, inspired by the light-induced charge-transfer properties of K(0.2)Co(1.4)[Fe(CN)(6)]·6.9H(2)O and related Prussian blue materials, the possibility of photo-induced magnetic changes was investigated for the [Co(3)Fe(2)] TBP complex. Optical reflectivity and magnetic susceptibility measurements were used to evaluate the photoactivity of these compounds. A comparison of these data before and after light irradiation demonstrates that (i) the spin crossover of the Fe(II) centers in the [Fe(3)Fe(2)] and [Fe(3)Co(2)] analogues and the (ii) charge transfer events in the [Co(3)Fe(2)] complex occur with temperature and irradiation. In addition, photomagnetic behavior is exhibited by all three compounds. The photo-conversion efficiency has been estimated at 20% of photo-induced high spin Fe(II) centers in [Fe(3)Co(2)], 30% of paramagnetic Co(II)-Fe(III) pairs in [Co(3)Fe(2)], and less than 2% of photo-induced high spin Fe(II) centers in [Fe(3)Fe(2)]. PMID:21391549

  4. GSK3 inactivation is involved in mitochondrial complex IV defect in transforming growth factor (TGF) {beta}1-induced senescence

    SciTech Connect

    Byun, Hae-Ok; Jung, Hyun-Jung; Seo, Yong-Hak; Lee, Young-Kyoung; Hwang, Sung-Chul; Seong Hwang, Eun; Yoon, Gyesoon

    2012-09-10

    Transforming growth factor {beta}1 (TGF {beta}1) induces Mv1Lu cell senescence by persistently producing mitochondrial reactive oxygen species (ROS) through decreased complex IV activity. Here, we investigated the molecular mechanism underlying the effect of TGF {beta}1 on mitochondrial complex IV activity. TGF {beta}1 progressively phosphorylated the negative regulatory sites of both glycogen synthase kinase 3 (GSK3) {alpha} and {beta}, corresponding well to the intracellular ROS generation profile. Pre-treatment of N-acetyl cysteine, an antioxidant, did not alter this GSK3 phosphorylation (inactivation), whereas pharmacological inhibition of GSK3 by SB415286 significantly increased mitochondrial ROS, implying that GSK3 phosphorylation is an upstream event of the ROS generation. GSK3 inhibition by SB415286 decreased complex IV activity and cellular O{sub 2} consumption rate and eventually induced senescence of Mv1Lu cell. Similar results were obtained with siRNA-mediated knockdown of GSK3. Moreover, we found that GSK3 not only exists in cytosol but also in mitochondria of Mv1Lu cell and the mitochondrial GSK3 binds complex IV subunit 6b which has no electron carrier and is topologically located in the mitochondrial intermembrane space. Involvement of subunit 6b in controlling complex IV activity and overall respiration rate was proved with siRNA-mediated knockdown of subunit 6b. Finally, TGF {beta}1 treatment decreased the binding of the subunit 6b to GSK3 and subunit 6b phosphorylation. Taken together, our results suggest that GSK3 inactivation is importantly involved in TGF {beta}1-induced complex IV defects through decreasing phosphorylation of the subunit 6b, thereby contributing to senescence-associated mitochondrial ROS generation.

  5. Complexin induces a conformational change at the membrane-proximal C-terminal end of the SNARE complex

    PubMed Central

    Choi, Ucheor B; Zhao, Minglei; Zhang, Yunxiang; Lai, Ying; Brunger, Axel T

    2016-01-01

    Complexin regulates spontaneous and activates Ca2+-triggered neurotransmitter release, yet the molecular mechanisms are still unclear. Here we performed single molecule fluorescence resonance energy transfer experiments and uncovered two conformations of complexin-1 bound to the ternary SNARE complex. In the cis conformation, complexin-1 induces a conformational change at the membrane-proximal C-terminal end of the ternary SNARE complex that specifically depends on the N-terminal, accessory, and central domains of complexin-1. The complexin-1 induced conformation of the ternary SNARE complex may be related to a conformation that is juxtaposing the synaptic vesicle and plasma membranes. In the trans conformation, complexin-1 can simultaneously interact with a ternary SNARE complex via the central domain and a binary SNARE complex consisting of syntaxin-1A and SNAP-25A via the accessory domain. The cis conformation may be involved in activation of synchronous neurotransmitter release, whereas both conformations may be involved in regulating spontaneous release. DOI: http://dx.doi.org/10.7554/eLife.16886.001 PMID:27253060

  6. RNA editing of microRNA prevents RNA-induced silencing complex recognition of target mRNA

    PubMed Central

    Cui, Yalei; Huang, Tianzhi; Zhang, Xiaobo

    2015-01-01

    MicroRNAs (miRNAs) integrate with Argonaut (Ago) to create the RNA-induced silencing complex, and regulate gene expression by silencing target mRNAs. RNA editing of miRNA may affect miRNA processing, assembly of the Ago complex and target mRNA binding. However, the function of edited miRNA, assembled within the Ago complex, has not been extensively investigated. In this study, sequence analysis of the Ago complex of Marsupenaeus japonicus shrimp infected with white spot syndrome virus (WSSV) revealed that host ADAR (adenosine deaminase acting on RNA) catalysed A-to-I RNA editing of a viral miRNA (WSSV-miR-N12) at the +16 site. This editing of the non-seed sequence did not affect association of the edited miRNA with the Ago protein, but inhibited interaction between the miRNA and its target gene (wsv399). The WSSV early gene wsv399 inhibited WSSV infection. As a result, the RNA editing of miRNA caused virus latency. Our results highlight a novel example of miRNA editing in the miRNA-induced silencing complex. PMID:26674414

  7. Complexin induces a conformational change at the membrane-proximal C-terminal end of the SNARE complex.

    PubMed

    Choi, Ucheor B; Zhao, Minglei; Zhang, Yunxiang; Lai, Ying; Brunger, Axel T

    2016-01-01

    Complexin regulates spontaneous and activates Ca(2+)-triggered neurotransmitter release, yet the molecular mechanisms are still unclear. Here we performed single molecule fluorescence resonance energy transfer experiments and uncovered two conformations of complexin-1 bound to the ternary SNARE complex. In the cis conformation, complexin-1 induces a conformational change at the membrane-proximal C-terminal end of the ternary SNARE complex that specifically depends on the N-terminal, accessory, and central domains of complexin-1. The complexin-1 induced conformation of the ternary SNARE complex may be related to a conformation that is juxtaposing the synaptic vesicle and plasma membranes. In the trans conformation, complexin-1 can simultaneously interact with a ternary SNARE complex via the central domain and a binary SNARE complex consisting of syntaxin-1A and SNAP-25A via the accessory domain. The cis conformation may be involved in activation of synchronous neurotransmitter release, whereas both conformations may be involved in regulating spontaneous release. PMID:27253060

  8. Methamphetamine-Induced Dopamine Transporter Complex Formation and Dopaminergic Deficits: The Role of D2 Receptor Activation

    PubMed Central

    Hadlock, Gregory C.; Chu, Pei-Wen; Walters, Elliot T.; Hanson, Glen R.

    2010-01-01

    Methamphetamine (METH) abuse is a serious public health issue. Of particular concern are findings that repeated high-dose administrations of METH cause persistent dopaminergic deficits in rodents, nonhuman primates, and humans. Previous studies have also revealed that METH treatment causes alterations in the dopamine transporter (DAT), including the formation of higher molecular mass DAT-associated complexes. The current study extends these findings by examining mechanisms underlying DAT complex formation. The association among DAT complex formation and other METH-induced phenomena, including alterations in vesicular monoamine transporter 2 (VMAT2) immunoreactivity, astrocytic activation [as assessed by increased glial fibrillary acidic protein (GFAP) immunoreactivity], and persistent dopaminergic deficits was also explored. Results revealed that METH-induced DAT complex formation and reductions in VMAT2 immunoreactivity precede increases in GFAP immunoreactivity. Furthermore, and as reported previously for DAT complexes, pretreatment with the D2 receptor antagonist eticlopride [S-(−)-3-chloro-5-ethyl-N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-hydroxy-2-methoxybenzamide hydrochloride] attenuated the decrease in VMAT2 immunoreactivity as assessed 24 h after METH treatment. DAT complexes distinct from those present 24 h after METH treatment, decreases in VMAT2 immunoreactivity, and increased GFAP immunoreactivity were present 48 to 72 h after METH treatment. Pretreatment with eticlopride attenuated each of these phenomena. Finally, DAT complexes were present 7 days after METH treatment, a time point at which VMAT2 and DAT monomer immunoreactivity were also reduced. Eticlopride pretreatment attenuated each of these phenomena. These findings provide novel insight into not only receptor-mediated mechanisms underlying the effects of METH but also the interaction among factors that probably are associated with the persistent dopaminergic deficits caused by the stimulant. PMID

  9. Dexamethasone -induced apoptosis of human monocytes exposed to immune complexes. Intervention of CD95- and XIAP-dependent pathways.

    PubMed

    Ottonello, L; Bertolotto, M; Montecucco, F; Dapino, P; Dallegri, F

    2005-01-01

    Monocytes and macrophages play a key role in the initiation and persistence of inflammatory reactions. The possibility to interfere with the survival of these cells, once recruited and activated at sites of inflammation, is an attractive therapeutic option. Although resting monocytes are susceptible to pharmacologically induced apoptosis, no data are available about the possibility to modulate the survival of activated monocytes. The present work was planned to investigate if dexamethasone is able to promote apoptosis of human monocytes activated by immune complexes. When monocytes were cultured with immune complexes, a dose-dependent inhibition of apoptosis was observed. Dexamethasone stimulated apoptosis of resting and activated monocytes in a dose-dependent manner. Both the immune complex inhibitory activity and dexamethasone stimulatory properties depend on NF-kappaB/XIAP and Ras/MEK/ERK/CD95 pathways. In fact, the exposure of monocytes to immune complexes increased NF-kB activation and XIAP expression, which in turn were inhibited by dexamethasone. On the other hand, immune complex-stimulated monocytes displayed a reduced expression of CD95, which is prevented by dexamethasone, as well as by MEK inhibitor U0126. Furthermore, anti-CD95 ZB4 mAb prevented dexamethasone-induced apoptosis in immune complex stimulated monocytes. Similarly, ZB4 inhibited dexamethasone-mediated augmentation of caspase 3 activity. The present findings suggest that Fc triggering by insoluble immune complexes result in the activation of two intracellular pathways crucial for the survival of monocytes: 1. Ras/MEK/ERK pathway responsible for the down-regulation of CD95 expression; 2. NF-kappaB pathway governing the expression of XIAP. Both the pathways are susceptible to inhibition by monocyte treatment with pharmacologic concentrations of dexamethasone. PMID:16164824

  10. A novel insulin mimetic vanadium-flavonol complex: synthesis, characterization and in vivo evaluation in STZ-induced rats.

    PubMed

    Pillai, Subramanian Iyyam; Subramanian, Sorimuthu Pillai; Kandaswamy, Muthusamy

    2013-05-01

    Since 1985, when Heyliger et al., first demonstrated a serendipitous discovery that oral administration of 0.8 mg/ml of sodium orthovanadate in drinking water to streptozotocin-induced diabetic rats resulted in normoglycemia, numerous extensive studies have been pursued on the anti-diabetic and insulinomimetic actions of vanadium. The acceptance of vanadium compounds as promising therapeutic antidiabetic agents has been slowed due to the concern for chronic toxicity associated with vanadium accumulation. In order to circumvent the toxic effects of vanadium, we have taken up a combinational approach wherein a novel vanadium-flavonol complex was synthesized, characterized and its toxic as well as insulin mimetic potential was evaluated in STZ-induced experimental diabetes in rats. The results indicate that the complex is non-toxic and possess anti-diabetic activity. PMID:23466606

  11. Proton exchange in acid-base complexes induced by reaction coordinates with heavy atom motions

    NASA Astrophysics Data System (ADS)

    Alavi, Saman; Taghikhani, Mahdi

    2012-06-01

    We extend previous work on nitric acid-ammonia and nitric acid-alkylamine complexes to illustrate that proton exchange reaction coordinates involve the rocking motion of the base moiety in many double hydrogen-bonded gas phase strong acid-strong base complexes. The complexes studied involve the biologically and atmospherically relevant glycine, formic, acetic, propionic, and sulfuric acids with ammonia/alkylamine bases. In these complexes, the magnitude of the imaginary frequencies associated with the proton exchange transition states are <400 cm-1. This contrasts with widely studied proton exchange reactions between symmetric carboxylic acid dimers or asymmetric DNA base pair and their analogs where the reaction coordinate is localized in proton motions and the magnitude of the imaginary frequencies for the transition states are >1100 cm-1. Calculations on complexes of these acids with water are performed for comparison. Variations of normal vibration modes along the reaction coordinate in the complexes are described.

  12. Inhibition of carrageenin-induced rat paw oedema by crotapotin, a polypeptide complexed with phospholipase A2.

    PubMed Central

    Landucci, E C; Antunes, E; Donato, J L; Faro, R; Hyslop, S; Marangoni, S; Oliveira, B; Cirino, G; de Nucci, G

    1995-01-01

    1. The effect of purified crotapotin, a non-toxic non-enzymatic chaperon protein normally complexed to a phospholipase A2 (PLA2) in South America rattlesnake venom, was studied in the acute inflammatory response induced by carrageenin (1 mg/paw), compound 48/80 (3 micrograms/paw) and 5-hydroxytryptamine (5-HT) (3 micrograms/paw) in the rat hind-paw. The effects of crotapotin on platelet aggregation, mast cell degranulation and eicosanoid release from guinea-pig isolated lung were also investigated. 2. Subplantar co-injection of crotapotin (1 and 10 micrograms/paw) with carrageenin or injection of crotapotin (10 micrograms/paw) into the contralateral paw significantly inhibited the carrageenin-induced oedema. This inhibition was also observed when crotapotin (10-30 micrograms/paw) was administered either intraperitoneally or orally. Subplantar injection of heated crotapotin (15 min at 60 degrees C) failed to inhibit carrageenin-induced oedema. Subplantar injection of crotapotin (10 micrograms/paw) also significantly inhibited the rat paw oedema induced by compound 48/80, but it did not affect 5-HT-induced oedema. 3. In adrenalectomized animals, subplantar injection of crotapotin markedly inhibited the oedema induced by carrageenin. The inhibitory effect of crotapotin was also observed in rats depleted of histamine and 5-HT stores. 4. Crotapotin (30 micrograms/paw) had no effect on either the histamine release induced by compound 48/80 in vitro or on the platelet aggregation induced by both arachidonic acid (1 nM) and platelet activating factor (1 microM) in human platelet-rich plasma. The platelet aggregation and thromboxane B2 (TXB2) release induced by thrombin (100 mu ml-1) in washed human platelets were also not affected by crotapotin.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7537590

  13. Investigating Storm-Induced Total Water Levels on Complex Barred Beaches

    NASA Astrophysics Data System (ADS)

    Cohn, N.; Ruggiero, P.; Walstra, D.

    2013-12-01

    Water levels in coastal environments are not static, but rather vary from a range of factors including mean sea level, tides, storm surge, and wave runup. Cumulatively these superimposed factors determine the total water level (TWL), the extent of which has major implications for coastal erosion and inundation during periods of high energy. Storm-induced, super-elevated water levels pose a threat to low lying coastal regions, as clearly demonstrated by recent events such as Hurricanes Sandy and Katrina. For this reason, the ability to accurately predict the TWL is crucial for both emergency managers and coastal planners. While some components of TWL are well understood (e.g., tides) there is still significant uncertainty in predicting runup, a process that can be a major contributor to instantaneous TWLs. Traditionally, empirical relationships derived from observational field data have been used to estimate runup, including wave setup and both incident and infragravity swash (Stockdon et al., 2006). While these formulations have shown skill in predicting the runup extent on natural beaches, these equations consider only the most basic contributing factors - namely the mean foreshore beach slope, the offshore wave height, and offshore wave period. Not included in these empirical estimates is the role of nearshore morphology on TWLs. However, it has long been recognized that nearshore sandbars act as natural barriers to coastal erosion during storm events by dissipating wave energy far from the beach face. Nonetheless, the influence of nearshore morphology on inner surf zone processes, including wave runup, is poorly understood. Recent pioneering studies (eg., Soldini et al., 2013 and Stephens et al., 2011) have explored the role of simple nearshore features (single Gaussian bars) on swash processes. Many locations in the world, however, are characterized by more complex morphologies such as multiple barred systems. Further, in many such places, including Columbia

  14. Specific Genetic Immunotherapy Induced by Recombinant Vaccine Alpha-Fetoprotein-Heat Shock Protein 70 Complex

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoping; Lin, Huanping; Wang, Qiaoxia

    Purposes: To construct a recombinant vaccine alpha-fetoprotein (AFP)-heat shock protein (HSP70) complex, and study its ability to induce specific CTL response and its protective effect against AFP-producing tumor. Material/Methods: A recombinant vaccine was constructed by conjugating mouse alpha-fetoprotein to heat shock protein 70. By way of intracutaneous injection, mice were primed and boosted with recombinant vaccine mAFP/HSP70, whereas single mAFP or HSP70 injection as controls. The ELISPOT and ELISA were used to measure the frequency of cells producing the cytokine IFN-γ in splenocytes and the level of anti-AFP antibody of serum from immunized mice respectively. In vivo tumor challenge were carried out to assess the immune effect of the recombinant vaccine. Results: By recombinant mAFP/HSP70 vaccine immunization, the results of ELISPOT and ELISA showed that the number of splenic cells producing IFN-γ and the level of anti-AFP antibody of serum were significantly higher in mAFP/HSP70 group than those in mAFP and HSP70 groups (108.50±11.70 IFN-γ spots/106 cells vs 41.60±10.40 IFN-γ spots/106 cells, 7.32±3.14 IFN-γ spots/106 cells, P<0.01; 156.32±10.42 μg/mL vs 66.52±7.35 μg/mL, 5.73±2.89 μg/mL, P<0.01). The tumor volume in mAFP/HSP70 group was significantly smaller than that in mAFP and HSP70 groups (42.44±7.14 mm3 vs 392.23±12.46 mm3, 838.63±13.84 mm3, P<0.01). Conclusions: The study further confirmed the function of heat shock protein 70's immune adjuvant. Sequential immunization with recombinant mAFP/HSP70 vaccine could generate effective antitumor immunity on AFP-producing tumor. The recombined mAFP/HSP70 vaccine may be suitable for serving as an immunotherapy for hepatocellular carcinoma.

  15. Trauma-Induced Coagulopathy Is Associated with a Complex Inflammatory Response in the Rat.

    PubMed

    Darlington, Daniel N; Gonzales, Mary D; Craig, Teresa; Dubick, Michael A; Cap, Andrew P; Schwacha, Martin G

    2015-08-01

    Severe trauma can lead to a coagulopathy in patients, which is associated with increased mortality. We developed a rat polytrauma model that demonstrates a similar progression of coagulopathy. Because coagulation is influenced by changes in inflammation, and this interrelationship is poorly understood, we have studied the progression of inflammation, and its correlation with coagulation, in this rat model of severe polytrauma. Sprague-Dawley rats were anesthetized with isoflurane. Polytrauma was induced by damaging 10 cm of small intestines, right and medial liver lobes, right leg skeletal muscle, femur fracture, and hemorrhaging 40% of blood volume. No resuscitation was given. Polytrauma and hemorrhage resulted in a significant decrease in the number of lymphocytes and an increase in monocytes and granulocytes. There was an increase in plasma proinflammatory cytokines: tumor necrosis factor α (40×), interleukin (IL)-6 (20×), IL-1β (16×), IL-17 (15×), interferon γ (10×), IL-1α (8×) and IL-12p70 (5×); anti-inflammatory cytokines: IL-10 (100×), IL-13 (16×), and IL-4 (5×); chemokines: growth-regulated protein/keratinocyte chemoattractant (30×), macrophage inflammatory protein 3α (10×), regulated and normal T-cell expressed and secreted (3×); and growth factors: vascular endothelial growth factor (5×), granulocyte macrophage colony-stimulating factor (6×), macrophage colony-stimulating factor (3×), granulocyte colony-stimulating factor (2×), and IL-5 (3×). There was a strong and significant correlation between prothrombin time, activated partial thromboplastin time, fibrinogen, and fibrin monomer concentration, and many cytokines. Polytrauma with hemorrhage is associated with a coagulopathy and a complex inflammatory response consisting of a concurrent rise in both proinflammatory and anti-inflammatory cytokines. The rise in plasma concentrations of chemokines and growth factors likely contribute to the mobilization of monocytes and granulocytes

  16. Atypical behavior in the electron capture induced dissociation of biologically relevant transition metal ion complexes of the peptide hormone oxytocin

    NASA Astrophysics Data System (ADS)

    Kleinnijenhuis, Anne J.; Mihalca, Romulus; Heeren, Ron M. A.; Heck, Albert J. R.

    2006-07-01

    Doubly protonated ions of the disulfide bond containing nonapeptide hormone oxytocin and oxytocin complexes with different transition metal ions, that have biological relevance under physiological conditions, were subjected to electron capture dissociation (ECD) to probe their structural features in the gas phase. Although, all the ECD spectra were strikingly different, typical ECD behavior was observed for complexes of the nonapeptide hormone oxytocin with Ni2+, Co2+ and Zn2+, i.e., abundant c/z' and a'/y backbone cleavages and ECD characteristic S-S and S-C bond cleavages were observed. We propose that, although in the oxytocin-transition metal ion complexes the metal ions serve as the main initial capture site, the captured electron is transferred to other sites in the complex to form a hydrogen radical, which drives the subsequent typical ECD fragmentations. The complex of oxytocin with Cu2+ displayed noticeably different ECD behavior. The fragment ions were similar to fragment ions typically observed with low-energy collision induced dissociation (CID). We propose that the electrons captured by the oxytocin-Cu2+ complex might be favorably involved in reducing the Cu2+ metal ion to Cu+. Subsequent energy redistribution would explain the observed low-energy CID-type fragmentations. Electron capture resulted also in quite different specific cleavage sites for the complexes of oxytocin with Ni2+, Co2+ and Zn2+. This is an indication for structural differences in these complexes possibly linked to their significantly different biological effects on oxytocin-receptor binding, and suggests that ECD may be used to study subtle structural differences in transition metal ion-peptide complexes.

  17. Antioxidant-induced changes of the AP-1 transcription complex are paralleled by a selective suppression of human papillomavirus transcription.

    PubMed Central

    Rösl, F; Das, B C; Lengert, M; Geletneky, K; zur Hausen, H

    1997-01-01

    Considering the involvement of a redox-regulatory pathway in the expression of human papillomaviruses (HPVs), HPV type 16 (HPV-16)-immortalized human keratinocytes were treated with the antioxidant pyrrolidine-dithiocarbamate (PDTC). PDTC induces elevated binding of the transcription factor AP-1 to its cognate recognition site within the viral regulatory region. Despite of increased AP-1 binding, normally indispensable for efficient HPV-16 transcription, viral gene expression was selectively suppressed at the level of initiation of transcription. Electrophoretic mobility supershift assays showed that the composition of the AP-1 complex, predominantly consisting of Jun homodimers in untreated cells, was altered. Irrespective of enhanced c-fos expression, c-jun was phosphorylated and became primarily heterodimerized with fra-1, which was also induced after PDTC incubation. Additionally, there was also an increased complex formation between c-jun and junB. Because both fra-1 and junB overexpression negatively interferes with c-jun/c-fos trans-activation of AP-1-responsive genes, our results suggest that the observed block in viral transcription is mainly the consequence of an antioxidant-induced reconstitution of the AP-1 transcription complex. Since expression of the c-jun/c-fos gene family is tightly regulated during cellular differentiation, defined reorganization of a central viral transcription factor may represent a novel mechanism controlling the transcription of pathogenic HPVs during keratinocyte differentiation and in the progression to cervical cancer. PMID:8985358

  18. The Dictyostelium prestalk inducer differentiation-inducing factor-1 (DIF-1) triggers unexpectedly complex global phosphorylation changes

    PubMed Central

    Sugden, Chris; Urbaniak, Michael D.; Araki, Tsuyoshi; Williams, Jeffrey G.

    2015-01-01

    Differentiation-inducing factor-1 (DIF-1) is a polyketide that induces Dictyostelium amoebae to differentiate as prestalk cells. We performed a global quantitative screen for phosphorylation changes that occur within the first minutes after addition of DIF-1, using a triple-label SILAC approach. This revealed a new world of DIF-1–controlled signaling, with changes in components of the MAPK and protein kinase B signaling pathways, components of the actinomyosin cytoskeletal signaling networks, and a broad range of small GTPases and their regulators. The results also provide evidence that the Ca2+/calmodulin–dependent phosphatase calcineurin plays a role in DIF-1 signaling to the DimB prestalk transcription factor. At the global level, DIF-1 causes a major shift in the phosphorylation/dephosphorylation equilibrium toward net dephosphorylation. Of interest, many of the sites that are dephosphorylated in response to DIF-1 are phosphorylated in response to extracellular cAMP signaling. This accords with studies that suggest an antagonism between the two inducers and also with the rapid dephosphorylation of the cAMP receptor that we observe in response to DIF-1 and with the known inhibitory effect of DIF-1 on chemotaxis to cAMP. All MS data are available via ProteomeXchange with identifier PXD001555. PMID:25518940

  19. Zinc(II)-Thiosemicarbazone Complexes Are Localized to the Lysosomal Compartment Where They Transmetallate with Copper Ions to Induce Cytotoxicity.

    PubMed

    Stacy, Alexandra E; Palanimuthu, Duraippandi; Bernhardt, Paul V; Kalinowski, Danuta S; Jansson, Patric J; Richardson, Des R

    2016-05-26

    As the di-2-pyridylketone thiosemicarbazone (DpT) and 2-acetylpyridine thiosemicarbazone (ApT) series show potent antitumor activity in vitro and in vivo, we synthesized their fluorescent zinc(II) complexes to assess their intracellular distribution. The Zn(II) complexes generally showed significantly greater cytotoxicity than the thiosemicarbazones alone in several tumor cell-types. Notably, specific structure-activity relationships demonstrated the importance of the di-2-pyridyl pharmacophore in their activity. Confocal fluorescence imaging and live cell microscopy showed that the Zn(II) complex of our lead compound, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), which is scheduled to enter clinical trials, was localized to lysosomes. Under lysosomal conditions, the Zn(II) complexes were shown to transmetallate with copper ions, leading to redox-active copper complexes that induced lysosomal membrane permeabilization (LMP) and cytotoxicity. This is the first study to demonstrate direct lysosomal targeting of our novel Zn(II)-thiosemicarbazone complexes that mediate their activity via transmetalation with copper ions and LMP. PMID:27023111

  20. Discovery of a dual-targeting organometallic ruthenium complex with high activity inducing early stage apoptosis of cancer cells.

    PubMed

    Du, Jun; Zhang, Erlong; Zhao, Yao; Zheng, Wei; Zhang, Yang; Lin, Yu; Wang, Zhaoying; Luo, Qun; Wu, Kui; Wang, Fuyi

    2015-12-01

    Ruthenium based complexes are promising antitumour candidates due to their lower toxicity and better water-solubility compared to the platinum antitumour complexes. An epidermal growth factor receptor (EGFR) has been found to be overexpressed in a large set of tumour cells. In this work, a series of organoruthenium complexes containing EGFR-inhibiting 4-anilinoquinazoline pharmacophores were synthesised and characterised. These complexes exhibited excellent inhibitory activity against EGFR and high affinity to interact with DNA via minor groove binding, featuring dual-targeting properties. In vitro screening demonstrated that the as-prepared ruthenium complexes are anti-proliferating towards a series of cancer cell lines, in particular the non-small-cell lung cancer cell line A549. Fluorescence-activated cell sorting analysis and fluorescence microscopy revealed that the most active complex 3 induced much more early-stage cell apoptosis than its cytotoxic arene ruthenium analogue and the EGFR-inhibiting 4-anilinoquinazolines, verifying the synergetic effect of the two mono-functional pharmacophores. PMID:26446567

  1. Characterisation of senescence-induced changes in light harvesting complex II and photosystem I complex of thylakoids of Cucumis sativus cotyledons: age induced association of LHCII with photosystem I.

    PubMed

    Prakash, Jogadhenu Syama Sundara; Baig, Masroor A; Bhagwat, Anil S; Mohanty, Prasanna

    2003-02-01

    Structure and function of chloroplasts are known to after during senescence. The senescence-induced specific changes in light harvesting antenna of photosystem II (PSII) and photosystem I (PSI) were investigated in Cucumis cotyledons. Purified light harvesting complex II (LHCII) and photosystem I complex were isolated from 6-day non-senescing and 27-day senescing Cucumis cotyledons. The chlorophyll a/b ratio of LHCII obtained from 6-day-old control cotyledons and their absorption, chlorophyll a fluorescence emission and the circular dichroism (CD) spectral properties were comparable to the LHCII preparations from other plants such as pea and spinach. The purified LHCII obtained from 27-day senescing cotyledons had a Chl a/b ratio of 1.25 instead of 1.2 as with 6-day LHCII and also exhibited significant changes in the visible CD spectrum compared to that of 6-day LHCII, indicating some specific alterations in the organisation of chlorophylls of LHCII. The light harvesting antenna of photosystems are likely to be altered due to aging. The room temperature absorption spectrum of LHCII obtained from 27-day senescing cotyledons showed changes in the peak positions. Similarly, comparison of 77K chlorophyll a fluorescence emission characteristics of LHCII preparation from senescing cotyledons with that of control showed a small shift in the peak position and the alteration in the emission profile, which is suggestive of possible changes in energy transfer within LHCII chlorophylls. Further, the salt induced aggregation of LHCII samples was lower, resulting in lower yields of LHCII from 27-day cotyledons than from normal cotyledons. Moreover, the PSI preparations of 6-day cotyledons showed Chl a/b ratios of 5 to 5.5, where as the PSI sample of 27-day cotyledons had a Chl a/b ratio of 2.9 suggesting LHCII association with PSI. The absorption, fluorescence emission and visible CD spectral measurements as well as the polypeptide profiles of 27-day cotyledon-PSI complexes

  2. Zolpidem Induced Sleep-related Eating and Complex Behaviors in a Patient with Obstructive Sleep Apnea and Restless Legs Syndrome.

    PubMed

    Park, Young-Min; Shin, Hyun-Woo

    2016-08-31

    Zolpidem-induced sleep-related complex behaviors (SRCB) with anterograde amnesia have been reported. We describe herein a case in which the development of zolpidem-induced sleep-related eating disorder (SRED) and SRCB was strongly suspected. A 71-year-old Korean male was admitted to the Department of Psychiatry due to his repetitive SRED and SRCB with anterograde amnesia, which he reported as having occurred since taking zolpidem. The patient also had restless legs syndrome (RLS) and obstructive sleep apnea (OSA). His baseline serum iron level was low at admission. Zolpidem discontinuation resulted in the immediate disappearance of his SRED, but did not affect his RLS symptoms. These symptoms rapidly improved after adding a single i.v. iron injection once daily, and so he was discharged to day-clinic treatment. These findings indicate that zolpidem can induce SRCB. Although the pathophysiology of zolpidem-induced SRED and other SRCB remains unclear, clinicians should carefully monitor for the potential induction of complex behaviors associated with zolpidem in patients with comorbid RLS or OSA. PMID:27489385

  3. Zolpidem Induced Sleep-related Eating and Complex Behaviors in a Patient with Obstructive Sleep Apnea and Restless Legs Syndrome

    PubMed Central

    Park, Young-Min; Shin, Hyun-Woo

    2016-01-01

    Zolpidem-induced sleep-related complex behaviors (SRCB) with anterograde amnesia have been reported. We describe herein a case in which the development of zolpidem-induced sleep-related eating disorder (SRED) and SRCB was strongly suspected. A 71-year-old Korean male was admitted to the Department of Psychiatry due to his repetitive SRED and SRCB with anterograde amnesia, which he reported as having occurred since taking zolpidem. The patient also had restless legs syndrome (RLS) and obstructive sleep apnea (OSA). His baseline serum iron level was low at admission. Zolpidem discontinuation resulted in the immediate disappearance of his SRED, but did not affect his RLS symptoms. These symptoms rapidly improved after adding a single i.v. iron injection once daily, and so he was discharged to day-clinic treatment. These findings indicate that zolpidem can induce SRCB. Although the pathophysiology of zolpidem-induced SRED and other SRCB remains unclear, clinicians should carefully monitor for the potential induction of complex behaviors associated with zolpidem in patients with comorbid RLS or OSA. PMID:27489385

  4. IL-15 complexes induce NK- and T-cell responses independent of type I IFN signaling during rhinovirus infection.

    PubMed

    Jayaraman, A; Jackson, D J; Message, S D; Pearson, R M; Aniscenko, J; Caramori, G; Mallia, P; Papi, A; Shamji, B; Edwards, M; Westwick, J; Hansel, T; Stanciu, L A; Johnston, S L; Bartlett, N W

    2014-09-01

    Rhinoviruses are among the most common viruses to infect man, causing a range of serious respiratory diseases including exacerbations of asthma and COPD. Type I IFN and IL-15 are thought to be required for antiviral immunity; however, their function during rhinovirus infection in vivo is undefined. In RV-infected human volunteers, IL-15 protein expression in fluid from the nasal mucosa and in bronchial biopsies was increased. In mice, RV induced type I IFN-dependent expressions of IL-15 and IL-15Rα, which in turn were required for NK- and CD8(+) T-cell responses. Treatment with IL-15-IL-15Rα complexes (IL-15c) boosted RV-induced expression of IL-15, IL-15Rα, IFN-γ, CXCL9, and CXCL10 followed by recruitment of activated, IFN-γ-expressing NK, CD8(+), and CD4(+) T cells. Treating infected IFNAR1(-/-) mice with IL-15c similarly increased IL-15, IL-15Rα, IFN-γ, and CXCL9 (but not CXCL10) expression also followed by NK-, CD8(+)-, and CD4(+)-T-cell recruitment and activation. We have demonstrated that type I IFN-induced IFN-γ and cellular immunity to RV was mediated by IL-15 and IL-15Rα. Importantly, we also show that IL-15 could be induced via a type I IFN-independent mechanism by IL-15 complex treatment, which in turn was sufficient to drive IFN-γ expression and lymphocyte responses. PMID:24472849

  5. Two field-induced slow magnetic relaxation processes in a mononuclear Co(ii) complex with a distorted octahedral geometry.

    PubMed

    Li, Jing; Han, Yuan; Cao, Fan; Wei, Rong-Min; Zhang, Yi-Quan; Song, You

    2016-05-31

    A distorted octahedral Co(II) complex is reported with homoscorpionate ligands. This complex comprised a field-induced single-molecule magnet, showing two slow relaxation processes under a low dc field (<800 Oe) and only one process under a high dc field (≥800 Oe), which was an unusually discovery for 3d metal ions. On the basis of the ac magnetic data, we show for the first time that one of the slow relaxation processes in the low dc field originates from intermolecular dipolar interactions. Interestingly, the Raman process is predominant in the spin reversal relaxation process. The origin of the behaviours of the complex was elucidated by ab initio calculations. PMID:27180637

  6. Fear induced complexity loss in the electrocardiogram of flight phobics: a multiscale entropy analysis.

    PubMed

    Bornas, Xavier; Llabrés, Jordi; Noguera, Miquel; López, Ana M A; Gelabert, Joan Miquel; Vila, Irene

    2006-10-01

    In this study we explored the changes in the variability and complexity of the electrocardiogram (ECG) of flight phobics (N=61) and a matched non-phobic control group (N=58) when they performed a paced breathing task and were exposed to flight related stimuli. Lower complexity/entropy values were expected in phobics as compared to controls. The phobic system complexity as well as the heart rate variability (HRV) were expected to be reduced by the exposure to fearful stimuli. The multiscale entropy (MSE) analysis revealed lower entropy values in phobics during paced breathing and exposure, and a complexity loss was observed in phobics during exposure to threatening situations. The expected HRV decreases were not found in this study. The discussion is focused on the distinction between variability and complexity measures of the cardiac output, and on the usefulness of the MSE analysis in the field of anxiety disorders. PMID:16839658

  7. HINT1 peptide/Hsp70 complex induces NK-cell-dependent immunoregulation in a model of autoimmune demyelination.

    PubMed

    Galazka, Grazyna; Jurewicz, Anna; Domowicz, Malgorzata; Cannella, Barbara; Raine, Cedric S; Selmaj, Krzysztof

    2014-10-01

    Heat shock proteins (Hsps) interact with the immune system and have been shown to contribute to immunoregulation. As efficient chaperones, Hsps bind many peptides and these complexes have many yet-to-be-clarified functions. We have shown that Hsp70 is complexed within the mouse CNS with peptide CLAFHDISPQAPTHFLVIPK derived from histidine triad nucleotide-binding protein-1 (HINT1₃₈₋₅₇/Hsp70). Only this complex, in contrast to other peptides complexed with Hsp70, was able to prevent experimental autoimmune encephalomyelitis (EAE) by induction of immunoregulatory mechanisms dependent on NK cells. Pretreatment of proteolipid protein peptide ₁₃₉₋₁₅₁(PLP₁₃₉₋₁₅₁) sensitized SJL/J mice with HINT1₃₈₋₅₇/Hsp70 prevented the development of EAE, suppressed PLP₁₃₉₋₁₅₁-induced T-cell proliferation, and blocked secretion of IL-17. HINT1₃₈₋₅₇ /Hsp70 stimulation of NK cells depended on synergistic activation of two NK-cell receptors, CD94 and NKG2D. NK cells with depleted CD94 or with blocked NKG2D did not inhibit PLP₁₃₉₋₁₅₁-induced spleen cell (SC) proliferation. The HINT1₃₈₋₅₇/Hsp70 complex enhanced surface expression of the NKG2D ligand-H60. Downstream signaling of CD94 and NKG2D converged at the adaptor proteins DAP10 and DAP12, and in response to HINT1₃₈₋₅₇ /Hsp70 stimulation, expression of DAP10 and DAP12 was significantly increased in NK cells. Thus, we have shown that the HINT1₃₈₋₅₇ /Hsp70 complex affects NK-cell function by enhancing NK-cell-dependent immunoregulation in the EAE model of autoimmune demyelination. PMID:25092109

  8. Chemical Swarming: Depending on Concentration, an Amphiphilic Ruthenium Polypyridyl Complex Induces Cell Death via Two Different Mechanisms.

    PubMed

    Siewert, Bianka; van Rixel, Vincent H S; van Rooden, Eva J; Hopkins, Samantha L; Moester, Miriam J B; Ariese, Freek; Siegler, Maxime A; Bonnet, Sylvestre

    2016-07-25

    The crystal structure and in vitro cytotoxicity of the amphiphilic ruthenium complex [3](PF6 )2 are reported. Complex [3](PF6 )2 contains a Ru-S bond that is stable in the dark in cell-growing medium, but is photosensitive. Upon blue-light irradiation, complex [3](PF6 )2 releases the cholesterol-thioether ligand 2 and an aqua ruthenium complex [1](PF6 )2 . Although ligand 2 and complex [1](PF6 )2 are by themselves not cytotoxic, complex [3](PF6 )2 was unexpectedly found to be as cytotoxic as cisplatin in the dark, that is, with micromolar effective concentrations (EC50 ), against six human cancer cell lines (A375, A431, A549, MCF-7, MDA-MB-231, and U87MG). Blue-light irradiation (λ=450 nm, 6.3 J cm(-2) ) had little influence on the cytotoxicity of [3](PF6 )2 after 6 h of incubation time, but it increased the cytotoxicity of the complex by a factor 2 after longer (24 h) incubation. Exploring the unexpected biological activity of [3](PF6 )2 in the dark elucidated an as-yet unknown bifaceted mode of action that depended on concentration, and thus, on the aggregation state of the compound. At low concentration, it acts as a monomer, inserts into the membrane, and can deliver [1](2+) inside the cell upon blue-light activation. At higher concentrations (>3-5 μm), complex [3](PF6 )2 forms supramolecular aggregates that induce non-apoptotic cell death by permeabilizing cell membranes and extracting lipids and membrane proteins. PMID:27373895

  9. Transformation of Tetracycline Antibiotics and Fe(II) and Fe(III) Species Induced by Their Complexation.

    PubMed

    Wang, Hui; Yao, Hong; Sun, Peizhe; Li, Desheng; Huang, Ching-Hua

    2016-01-01

    Tetracycline antibiotics (TCs) are frequently detected micropollutants and are known to have a strong tendency to complex with metal ions such as Fe(II) and Fe(III) in aquatic environments. Experiments with Fe(II) and TCs showed that the complexation of Fe(II) with tetracycline (TTC), oxytetracycline (OTC), or chlorotetracycline (CTC) could lead to the accelerated oxidation of Fe(II) and the promoted degradation of TCs simultaneously. The reaction started with complexation of Fe(II) with TC followed by oxidation of the Fe(II)-TC complex by dissolved oxygen to generate a Fe(III)-TC complex and reactive oxygen species (ROS). The ROS (primarily ·OH) then degraded TC. The oxidation rate constants of Fe(II) in the Fe(II)-H2L and Fe(II)-HL complexes were 0.269 and 1.511 min(-1), respectively, at ambient conditions (pH 7, 22 °C, and PO2 of 0.21 atm), which were about 60 and 350 times of the oxidation rate of uncomplexed Fe(II). Humic acids (HA) compete with TCs for Fe(II), but the effect was negligible at moderate HA concentrations (≤10 mg·L(-1)). Experiments with Fe(III) and TCs showed that the complexation of Fe(III) with TC could generate oxidized TC and Fe(II) without the need of oxygen at a relatively slower rate compared to the reaction involving Fe(II), O2, and TCs. These findings indicate the mutually influenced environmental transformation of TCs and Fe(II) and Fe(III) induced by their complexation. These newly identified reactions could play an important role in affecting the environmental fate of TCs and cycling of Fe(II) and Fe(III) in TCs-contaminated water and soil systems. PMID:26618388

  10. Wnt signalling induces accumulation of phosphorylated β-catenin in two distinct cytosolic complexes.

    PubMed

    Gerlach, Jan P; Emmink, Benjamin L; Nojima, Hisashi; Kranenburg, Onno; Maurice, Madelon M

    2014-11-01

    Wnt/β-catenin signalling controls development and adult tissue homeostasis and causes cancer when inappropriately activated. In unstimulated cells, an Axin1-centred multi-protein complex phosphorylates the transcriptional co-activator β-catenin, marking it for degradation. Wnt signalling antagonizes β-catenin proteolysis, leading to its accumulation and target gene expression. How Wnt stimulation alters the size distribution, composition and activity of endogenous Axin1 complexes remains poorly understood. Here, we employed two-dimensional blue native/SDS-PAGE to analyse endogenous Axin1 and β-catenin complexes during Wnt signalling. We show that the size range of Axin1 complexes is conserved between species and remains largely unaffected by Wnt stimulation. We detect a striking Wnt-dependent, cytosolic accumulation of both non-phosphorylated and phosphorylated β-catenin within a 450 kDa Axin1-based complex and in a distinct, Axin1-free complex of 200 kDa. These results argue that during Wnt stimulation, phosphorylated β-catenin is released from the Axin1 complex but fails to undergo immediate degradation. Importantly, in APC-mutant cancer cells, the distribution of Axin1 and β-catenin complexes strongly resembles that of Wnt-stimulated cells. Our findings argue that Wnt signals and APC mutations interfere with the turnover of phosphorylated β-catenin. Furthermore, our results suggest that the accumulation of small-sized β-catenin complexes may serve as an indicator of Wnt pathway activity in primary cancer cells. PMID:25392450

  11. Theoretical calculation of light-induced forces and torques on complex microrotors

    NASA Astrophysics Data System (ADS)

    Liu, Yuxiang; Zhu, Anding; Huang, Wenhao

    2004-12-01

    In this letter, we propose the new theoretical investigation on the optical forces and torques on complex microrotors. On the basis of R. C. Gauthier"s hybrid ray-wave model, the optical forces and toques on two complex asymmetric micro-objects, the conical microrotor and the helical microrotor, are analyzed. The viscous drag torque is estimated by Stokes flow to obtain the rotational speed. The results of our computation agree well with the previously published experimental results, which indicates that our approach of the optical torque calculation is suitable for other complex microrotors and that the theoretical calculation is very helpful to optimum design of light-driven microrotors.

  12. Immobilized immune complexes induce neutrophil extracellular trap release by human neutrophil granulocytes via FcγRIIIB and Mac-1.

    PubMed

    Behnen, Martina; Leschczyk, Christoph; Möller, Sonja; Batel, Tobit; Klinger, Matthias; Solbach, Werner; Laskay, Tamás

    2014-08-15

    Canonical neutrophil antimicrobial effector mechanisms, such as degranulation, production of reactive oxygen species, and release of neutrophil extracellular traps (NETs), can result in severe pathology. Activation of neutrophils through immune complexes (ICs) plays a central role in the pathogenesis of many autoimmune inflammatory diseases. In this study, we report that immobilized ICs (iICs), which are hallmarks of several autoimmune diseases, induce the release of NETs from primary human neutrophils. The iIC-induced NET formation was found to require production of reactive oxygen species by NADPH oxidase and myeloperoxidase and to be mediated by FcγRIIIb. Blocking of the β2 integrin macrophage-1 Ag but not lymphocyte function-associated Ag-1 abolished iIC-induced NET formation. This suggests that FcγRIIIb signals in association with macrophage-1 Ag. As intracellular signaling pathways involved in iIC-induced NET formation we identified the tyrosine kinase Src/Syk pathway, which downstream regulates the PI3K/Akt, p38 MAPK, and ERK1/2 pathways. To our knowledge, the present study shows for the first time that iICs induce NET formation. Thus, we conclude that NETs contribute to pathology in autoimmune inflammatory disorders associated with surface-bound ICs. PMID:25024378

  13. Chrysin-organogermanium (IV) complex induced Colo205 cell apoptosis-associated mitochondrial function and anti-angiogenesis.

    PubMed

    Yang, Fen; Gong, Longcai; Jin, Hua; Pi, Jiang; Bai, Haihua; Wang, Hong; Cai, Huaihong; Yang, Peihui; Cai, Jiye

    2015-01-01

    Colorectal cancer, a kind of malignant cancer, has more than 1 million new patients and results in 0.5 million deaths every year globally based on the estimation of Globocan in 2008. One of the most important issues against colon cancer is tumor metastasis. Anti-angiogenesis, a form of targeted therapy uses drugs or other substances to prevent the new blood vessel formation, which is critical for tumor metastasis. In our previous studies, we have demonstrated a simple method to synthesize Chry-Ge complex through the reaction between chrysin and triphenylgermanium bromide. In this work, we investigated the mechanism of Chry-Ge induced Colo205 cell apoptosis. We found that Chry-Ge could induce apoptosis in Colo205 cells in mitochondrial-dependent pathway, cause the reorganization of cytoskeleton and induce the damage of nucleus in Colo205 cells. Besides, Chry-Ge was also found to induce membrane ultrastructural changes in Colo205 cells by AFM. Further, we found that Chry-Ge can inhibit tube formation of human umbilical vascular endothelial cell in vitro. Chry-Ge was also tested in vivo in the chicken chorioallantoic membrane (CAM) assay and found to inhibit bFGF-treated CAMs development. These results suggested that Chry-Ge could induce Colo205 cell apoptosis by mitochondrial pathway and anti-angiogenesis, highlighting the use of organic germanium agents for the treatment of colorectal cancer. PMID:25914235

  14. A chiral 6-membered N-heterocyclic carbene copper(I) complex that induces high stereoselectivity.

    PubMed

    Park, Jin Kyoon; Lackey, Hershel H; Rexford, Matthew D; Kovnir, Kirill; Shatruk, Michael; McQuade, D Tyler

    2010-11-01

    A chiral 6-membered annulated N-heterocyclic (6-NHC) copper complex that catalyzes β-borylations with high yield and enantioselectivity was developed. The chiral 6-NHC copper complex is easy to prepare on the gram scale and is very active, showing 10,000 turnovers at 0.01 mol % of catalyst without significant decrease of enantioselectivity and with useful reaction rates. PMID:20919706

  15. Xanthohumol induces generation of reactive oxygen species and triggers apoptosis through inhibition of mitochondrial electron transfer chain complex I.

    PubMed

    Zhang, Bo; Chu, Wei; Wei, Peng; Liu, Ying; Wei, Taotao

    2015-12-01

    Xanthohumol is a prenylflavonoid extracted from hops (Humulus lupulus). It possesses anti-cancer and anti-inflammatory activities in vitro and in vivo, and offers therapeutic benefits for treatment of metabolic syndromes. However, the precise mechanisms underlying its pharmacological effects remain to be elucidated, together with its cellular target. Here, we provide evidence that xanthohumol directly interacts with the mitochondrial electron transfer chain complex I (NADH dehydrogenase), inhibits the oxidative phosphorylation, triggers the production of reactive oxygen species, and induces apoptosis. In addition, we show that as a result of the inhibition of the mitochondrial oxidative phosphorylation, xanthohumol exposure causes a rapid decrease of mitochondrial transmembrane potential. Furthermore, we showed that xanthohumol up-regulates the glycolytic capacity in cells, and thus compensates cellular ATP generation. Dissection of the multiple steps of aerobic respiration by extracellular flux assays revealed that xanthohumol specifically inhibits the activity of mitochondrial complex I, but had little effect on that of complex II, III and IV. Inhibition of complex I by xanthohumol caused the overproduction of reactive oxygen species, which are responsible for the induction of apoptosis in cancer cells. We also found that isoxanthohumol, the structural isomer of xanthohumol, is inactive to cells, suggesting that the reactive 2-hydroxyl group of xanthohumol is crucial for its targeting to the mitochondrial complex I. Together, the remodeling of cell metabolism revealed here has therapeutic potential for the use of xanthohumol. PMID:26453927

  16. Oxidation of 2-propanol ligands during collision-induced dissociation of a gas-phase uranyl complex

    NASA Astrophysics Data System (ADS)

    van Stipdonk, Michael J.; Chien, Winnie; Anbalagan, Victor; Gresham, Garold L.; Groenewold, Gary S.

    2004-10-01

    We demonstrate, by way of multi-stage tandem mass spectrometry and extensive deuterium labeling, that 2-propanol is converted to acetone, and 2-propoxide to acetaldehyde, when monopositive 2-propanol-coordinated uranyl-ligand cations are subjected to collision-induced dissociation in the gas-phase environment of an ion trap mass spectrometer. A species with formula [(UO2OCH(CH3)2)(HOCH(CH3)2)]+, derived from dissociation of the gas-phase precursor [(UO2NO3)(HOCH(CH3)2)3]+ eliminates two H atoms and CH3 in consecutive stages to generate a monopositive complex composed of the U(V) species UO2+ coordinated by acetone and acetaldehyde, i.e. [UO2+(OC(CH3)2)(OC(H)CH3)]. Dissociation of this latter ion resulted in elimination of the two coordinating carbonyl ligands in two consecutive dissociation stages to leave UO2+. Analogous reactions were not observed for uranyl complexes containing 1-propanol or 2-methyl-2-propanol, or for cationic complexes with divalent metals such as Ni2+, Co2+, Pb2+ and Ca2+. One explanation for these reactions is bond insertion by the metal center in the bis-ligated uranyl complex, which would be expected to have an LUMO consisting of unoccupied 6d-orbitals that would confer transition metal-like behavior on the complex.

  17. Investigating anthropically induced effects in streamflow dynamics by using permutation entropy and statistical complexity analysis: A case study

    NASA Astrophysics Data System (ADS)

    Stosic, Tatijana; Telesca, Luciano; de Souza Ferreira, Diego Vicente; Stosic, Borko

    2016-09-01

    In this paper we investigated the influence of the construction of Sobradinho dam on daily streamflow of São Francisco river, Brazil, using permutation entropy method. We analyzed a long daily streamflow time series recorded during the period 1929-2010 encompassing the construction of Sobradinho dam between 1973 and 1979. We found that the original and deseasonalized streamflow time series are characterized by clear different complexity and entropy patterns before the construction of the dam; while, after it, their degree of randomness and complexity are nearly identical. Furthermore, investigating the oscillatory behavior of the entropy and complexity time variation, the periodicity of 3.67 years was identified, identical to one of the main periodicities revealed in the Multivariate ENSO Index (MEI). Such finding confirms the close relationship between streamflow dynamics and ENSO phenomenon. After the construction of the dam, the time variation of entropy and complexity changes almost abruptly toward stochastic regime characterized by higher entropy and lower complexity. Although the dam operations could be considered responsible for such abrupt dynamical change in the streamflow, we cannot exclude the presence of a co-induced ENSO effect; in fact, the analysis of MEI shows a strikingly similar and concomitant change in the long-term trend, identified by using the singular spectrum analysis.

  18. Collision-Induced Infrared Absorption by Collisional Complexes in Dense Hydrogen-Helium Gas Mixtures at Thousands of Kelvin

    NASA Astrophysics Data System (ADS)

    Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

    2011-06-01

    The interaction-induced absorption by collisional pairs of H{_2} molecules is an important opacity source in the atmospheres of the outer planets and cool stars. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H{_2}-H{_2}, H{_2}-He, and H{_2}-H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin. Laboratory measurements of interaction-induced absorption spectra by H{_2} pairs exist only at room temperature and below. We show that our results reproduce these measurements closely, so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures. L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, "Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin", International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, "Collision-induced absorption by H{_2} pairs: From hundreds to thousands of Kelvin," J. Phys. Chem. A, published online, DOI: 10.1021/jp109441f L. Frommhold, M. Abel, F. Wang, M. Gustafsson, X. Li, and K. L. C. Hunt, "Infrared atmospheric emission and absorption by simple molecular complexes, from first principles", Mol. Phys. 108, 2265, 2010

  19. Experimental elucidation of vacancy complexes associated with hydrogen ion-induced splitting of bulk GaN

    SciTech Connect

    Moutanabbir, O.; Scholz, R.; Goesele, U.; Guittoum, A.; Jungmann, M.; Butterling, M.; Krause-Rehberg, R.; Anwand, W.; Egger, W.; Sperr, P.

    2010-03-15

    We present a detailed study of the thermal evolution of H ion-induced vacancy related complexes and voids in bulk GaN implanted under ion-cut conditions. By using transmission electron microscopy, we found that the damage band in as-implanted GaN is decorated with a high density of nanobubbles of approx1-2 nm in diameter. Variable energy Doppler broadening spectroscopy showed that this band contains vacancy clusters and voids. In addition to vacancy clusters, the presence of V{sub Ga}, V{sub Ga}-H{sub 2}, and V{sub Ga}V{sub N} complexes was evidenced by pulsed low-energy positron lifetime spectroscopy. Subtle changes upon annealing in these vacancy complexes were also investigated. As a general trend, a growth in open-volume defects is detected in parallel to an increase in both size and density of nanobubbles. The observed vacancy complexes appear to be stable during annealing. However, for temperatures above 450 deg. C, unusually large lifetimes were measured. These lifetimes are attributed to the formation of positronium in GaN. Since the formation of positronium is not possible in a dense semiconductor, our finding demonstrates the presence of sufficiently large open-volume defects in this temperature range. Based on the Tao-Eldrup model, the average lattice opening during thermal annealing was quantified. We found that a void diameter of 0.4 nm is induced by annealing at 600 deg. C. The role of these complexes in the subsurface microcracking is discussed.

  20. The diadinoxanthin diatoxanthin cycle induces structural rearrangements of the isolated FCP antenna complexes of the pennate diatom Phaeodactylum tricornutum.

    PubMed

    Schaller-Laudel, Susann; Volke, Daniela; Redlich, Matthias; Kansy, Marcel; Hoffmann, Ralf; Wilhelm, Christian; Goss, Reimund

    2015-11-01

    The study investigated the influence of the xanthophyll cycle pigments diadinoxanthin (DD) and diatoxanthin (Dt) on the spectroscopic characteristics, structure and protein composition of isolated fucoxanthin chlorophyll protein (FCP) complexes of the pennate diatom Phaeodactylum tricornutum. 77 K fluorescence emission spectra revealed that Dt-containing FCP complexes showed a characteristic long wavelength fluorescence emission at 700 nm at a pH-value of 5 whereas DD-enriched FCPs retained the typical 680 nm fluorescence emission maximum of isolated FCPs. The 700 nm emission in Dt-containing FCPs indicates an aggregation of antenna complexes and is a typical feature of the quenching site Q1 in recent models for non-photochemical fluorescence quenching (NPQ). A comparable long-wavelength fluorescence emission was found in FCP complexes prepared with either triton X-100 or n-dodecyl β-D-maltoside as detergent. A treatment of the FCP complexes at low pH-values in the presence of a high concentration of Mg(2+) ions showed that the extent of FCP aggregation which leads to the 700 nm fluorescence emission is different from the macro-aggregation of antenna complexes in higher plants. Protein analyses by mass spectrometry showed that the protein composition of the DD- and Dt-enriched FCP complexes was comparable. However, the Lhcf6 and Lhcr1 polypeptides were only found in Dt-enriched FCPs isolated with dodecyl maltoside whereas the Lhcf17 protein was only detected in DD-enriched FCPs prepared with triton. With respect to low pH-induced antenna aggregation it is important that the Lhcx1 protein was found in both DD- and Dt-enriched FCPs, albeit with only two peptides with confident scores. PMID:26368016

  1. Protein adsorption induced bridging flocculation: the dominant entropic pathway for nano-bio complexation

    NASA Astrophysics Data System (ADS)

    Eren, Necla Mine; Narsimhan, Ganesan; Campanella, Osvaldo H.

    2016-02-01

    Lysozyme-silica interactions and the resulting complexation were investigated through adsorption isotherms, dynamic and electrophoretic light scattering, circular dichroism (CD), and isothermal titration calorimetry (ITC). A thermodynamic analysis of ITC data revealed the existence of two binding modes during protein-nanoparticle complexation. Both binding modes are driven by the cooperation of a favorable enthalpy in the presence of a dominating entropy gain. The first binding mode has a higher binding affinity, a lower equilibrium stoichiometry and is driven by a higher entropic contribution compared to the second type. The observed favorable enthalpy gain in both modes is attributed to non-covalent complexation whereas the entropy gain is associated with the re-organization of the silica surface including not only the solvent and counter ion release, but also the protein's conformational changes. Possible mechanisms are proposed to explain non-covalent complexations for each binding mode by relating the changes in the zeta potential and hydrodynamic radius to the obtained adsorption isotherms and calorimetry profile. Based on all these findings, it is proposed that lysozyme adsorption on nano-silica is the result of protein-nanoparticle and protein-protein interactions that further leads to spontaneous, non-directional and random complexation of silica through bridging flocculation.Lysozyme-silica interactions and the resulting complexation were investigated through adsorption isotherms, dynamic and electrophoretic light scattering, circular dichroism (CD), and isothermal titration calorimetry (ITC). A thermodynamic analysis of ITC data revealed the existence of two binding modes during protein-nanoparticle complexation. Both binding modes are driven by the cooperation of a favorable enthalpy in the presence of a dominating entropy gain. The first binding mode has a higher binding affinity, a lower equilibrium stoichiometry and is driven by a higher entropic

  2. Up-Regulation of Human Inducible Nitric Oxide Synthase by p300 Transcriptional Complex.

    PubMed

    Guo, Zhong; Zheng, Liang; Liao, Xinghua; Geller, David

    2016-01-01

    p300, a ubiquitous transcription coactivator, plays an important role in gene activation. Our previous work demonstrated that human inducible nitric oxide synthase (hiNOS) expression can be highly induced with the cytokine mixture (CM) of TNF-α + IL-1β + IFN-γ. In this study, we investigated the functional role of p300 in the regulation of hiNOS gene expression. Our initial data showed that overexpression of p300 significantly increased the basal and cytokine-induced hiNOS promoter activities in A549 cells. Interestingly, p300 activated cytokine-induced hiNOS transcriptional activity was completely abrogated by deleting the upstream hiNOS enhancer at -5 kb to -6 kb in the promoter. Furthermore, p300 over-expression increased cytokine-induced transcriptional activity on a heterologous minimal TK promoter with the same hiNOS enhancer. Site-directed mutagenesis of the hiNOS AP-1 motifs revealed that an intact upstream (-5.3 kb) AP-1 binding site was critical for p300 mediated cytokine-induced hiNOS transcription. Furthermore, our ChIP analysis demonstrated that p300 was binding to Jun D and Fra-2 proteins at -5.3 kb AP-1 binding site in vivo. Lastly, our 3C assay was able to detect a long DNA loop between the hiNOS enhancer and core promoter site, and ChIP loop assay confirmed that p300 binds to AP-1 and RNA pol II proteins. Overall, our results suggest that coactivator p300 mediates cytokine-induced hiNOS transactivation by forming a distant DNA loop between its enhancer and core promoter region. PMID:26751080

  3. Deoxynivanelol and Fumonisin, Alone or in Combination, Induce Changes on Intestinal Junction Complexes and in E-Cadherin Expression

    PubMed Central

    Basso, Karina; Gomes, Fernando; Loureiro Bracarense, Ana Paula

    2013-01-01

    Fusariotoxins such as fumonisin B1 (FB1) and deoxynivalenol (DON) cause deleterious effects on the intestine of pigs. The aim of this study was to evaluate the effect of these mycotoxins, alone and in combination, on jejunal explants from piglets, using histological, immunohistochemical and ultrastructural assays. Five 24-day old pigs were used for sampling the explants. Forty-eight explants were sampled from each animal. Explants were incubated for 4 hours in culture medium and medium containing FB1 (100 µM), DON (10 µM) and both mycotoxins (100 µM FB1 plus 10 µM DON). Exposure to all treatments induced a significant decrease in the normal intestinal morphology and in the number of goblet cells, which were more severe in explants exposed to DON and both mycotoxins. A significant reduction in villus height occurred in groups treated with DON and with co-contamination. Expression of E-cadherin was significantly reduced in explants exposed to FB1 (40%), DON (93%) and FB1 plus DON (100%). The ultrastructural assay showed increased intercellular spaces and no junction complexes on enterocytes exposed to mycotoxins. The present data indicate that FB1 and DON induce changes in cell junction complexes that could contribute to increase paracellular permeability. The ex vivo model was adequate for assessing intestinal toxicity induced by exposure of isolated or associated concentrations of 100 µM of FB1 and 10 µM of DON. PMID:24287571

  4. A UV–Induced Genetic Network Links the RSC Complex to Nucleotide Excision Repair and Shows Dose-Dependent Rewiring

    PubMed Central

    Srivas, Rohith; Costelloe, Thomas; Carvunis, Anne-Ruxandra; Sarkar, Sovan; Malta, Erik; Sun, Su Ming; Pool, Marijke; Licon, Katherine; van Welsem, Tibor; van Leeuwen, Fred; McHugh, Peter J.; van Attikum, Haico; Ideker, Trey

    2014-01-01

    SUMMARY Efficient repair of UV-induced DNA damage requires the precise coordination of nucleotide excision repair (NER) with numerous other biological processes. To map this crosstalk, we generated a differential genetic interaction map centered on quantitative growth measurements of >45,000 double mutants before and after different doses of UV radiation. Integration of genetic data with physical interaction networks identified a global map of 89 UV-induced functional interactions amongst 62 protein complexes, including a number of links between the RSC complex and several NER factors. We show that RSC is recruited to both silenced and transcribed loci following UV damage where it facilitates efficient repair by promoting nucleosome remodeling. Finally, a comparison of the response to high versus low levels of UV shows that the degree of genetic rewiring correlates with dose of UV and reveals a network of dose-specific interactions. This study makes available a large resource of UV-induced interactions, and it illustrates a methodology for identifying dose-dependent interactions based on quantitative shifts in genetic networks. PMID:24360959

  5. A conserved virus-induced cytoplasmic TRAMP-like complex recruits the exosome to target viral RNA for degradation.

    PubMed

    Molleston, Jerome M; Sabin, Leah R; Moy, Ryan H; Menghani, Sanjay V; Rausch, Keiko; Gordesky-Gold, Beth; Hopkins, Kaycie C; Zhou, Rui; Jensen, Torben Heick; Wilusz, Jeremy E; Cherry, Sara

    2016-07-15

    RNA degradation is tightly regulated to selectively target aberrant RNAs, including viral RNA, but this regulation is incompletely understood. Through RNAi screening in Drosophila cells, we identified the 3'-to-5' RNA exosome and two components of the exosome cofactor TRAMP (Trf4/5-Air1/2-Mtr4 polyadenylation) complex, dMtr4 and dZcchc7, as antiviral against a panel of RNA viruses. We extended our studies to human orthologs and found that the exosome as well as TRAMP components hMTR4 and hZCCHC7 are antiviral. While hMTR4 and hZCCHC7 are normally nuclear, infection by cytoplasmic RNA viruses induces their export, forming a cytoplasmic complex that specifically recognizes and induces degradation of viral mRNAs. Furthermore, the 3' untranslated region (UTR) of bunyaviral mRNA is sufficient to confer virus-induced exosomal degradation. Altogether, our results reveal that signals from viral infection repurpose TRAMP components to a cytoplasmic surveillance role where they selectively engage viral RNAs for degradation to restrict a broad range of viruses. PMID:27474443

  6. The biphosphinic paladacycle complex induces melanoma cell death through lysosomal-mitochondrial axis modulation and impaired autophagy.

    PubMed

    Gigli, Rafael; Pereira, Gustavo J S; Antunes, Fernanda; Bechara, Alexandre; Garcia, Daniel M; Spindola, Daniel G; Jasiulionis, Mirian G; Caires, Antonio C F; Smaili, Soraya S; Bincoletto, Claudia

    2016-01-01

    Recently, palladium complexes have been extensively studied as cyclization of these complexes by cyclometallation reactions increased their stability making them promising antitumor compounds. In this study, we have investigated apoptosis induced by the Biphosphinic Paladacycle Complex (BPC11) and possible cross talk between apoptosis and autophagy in cell line models of metastatic (Tm5) and non-metastatic (4C11-) melanoma. The BPC11-induced cell death in melanoma involved the lysosomal-mitochondrial axis, which is characterized by LMP, CatB activation and increased Bax protein levels following its translocation to mitochondria. Mitochondrial hyperpolarization, followed by membrane potential dissipation and cleavage of caspase-3, also resulted in cell death after 24 h of incubation. We also found that BPC11-mediated LC3II formation and increased p62 protein levels, suggesting blocked autophagy, probably due to LMP. Interestingly, the treatment of Tm5 and 4C11(-) cells with 3-methyladenine (3-MA), an inhibitor of the initial stage of autophagy, potentiated the effects of BPC11. We conclude that BPC11 is an anti-melanoma agent and that autophagy may be acting as a mechanism of melanoma cells resistance. Also, these data highlight the importance of studies involving autophagy and apoptosis during pre-clinical studies of new drugs with anticancer properties. PMID:26599531

  7. TOM-independent complex formation of Bax and Bak in mammalian mitochondria during TNFalpha-induced apoptosis.

    PubMed

    Ross, K; Rudel, T; Kozjak-Pavlovic, V

    2009-05-01

    The Bcl-2 family proteins Bax and Bak are activated in response to many apoptotic stimuli. As a consequence of activation, Bax and Bak oligomerize and permeabilize the outer mitochondrial membrane to permit the release of apoptosis-inducing factors. It still remains unclear whether these proteins require components of the mitochondrial protein import machinery for their function at the mitochondria. Here, we addressed this question by using inducible RNA interference for the study of protein import in mammalian mitochondria. After induction of apoptosis, we could not detect any impact of the absence of Tom22, Tom70, Tom40, Sam50 or metaxins on the translocation of Bax and formation of Bax and Bak complexes in mitochondria. In in vitro import studies, loss of these import and assembly proteins had no or only slight effect on the formation of complexes by radiolabeled Bax and Bak. We conclude that the import and assembly machineries of mammalian mitochondria have no impact on the translocation and complex assembly of Bax and Bak upon apoptosis induction. PMID:19165229

  8. Cytotoxic hydrogen bridged ruthenium quinaldamide complexes showing induced cancer cell death by apoptosis.

    PubMed

    Lord, Rianne M; Allison, Simon J; Rafferty, Karen; Ghandhi, Laura; Pask, Christopher M; McGowan, Patrick C

    2016-08-16

    This report presents the first known p-cymene ruthenium quinaldamide complexes which are stabilised by a hydrogen-bridging atom, [{(p-cym)Ru(II)X(N,N)}{H(+)}{(N,N)XRu(II)(p-cym)}][PF6] (N,N = functionalised quinaldamide and X = Cl or Br). These complexes are formed by a reaction of [p-cymRu(μ-X)2]2 with a functionalised quinaldamide ligand. When filtered over NH4PF6, and under aerobic conditions the equilibrium of NH4PF6 ⇔ NH3 + HPF6 enables incorporation of HPF6 and the stabilisation of two monomeric ruthenium complexes by a bridging H(+), which are counter-balanced by a PF6 counterion. X-ray crystallographic analysis is presented for six new structures with OO distances of 2.420(4)-2.448(15) Å, which is significant for strong hydrogen bonds. Chemosensitivity studies against HCT116, A2780 and cisplatin-resistant A2780cis human cancer cells showed the ruthenium complexes with a bromide ancillary ligand to be more potent than those with a chloride ligand. The 4'-fluoro compounds show a reduction in potency for both chloride and bromide complexes against all cell lines, but an increase in selectivity towards cancer cells compared to non-cancer ARPE-19 cells, with a selectivity index >1. Mechanistic studies showed a clear correlation between IC50 values and induction of cell death by apoptosis. PMID:27417660

  9. Protein adsorption induced bridging flocculation: the dominant entropic pathway for nano-bio complexation.

    PubMed

    Eren, Necla Mine; Narsimhan, Ganesan; Campanella, Osvaldo H

    2016-02-14

    Lysozyme-silica interactions and the resulting complexation were investigated through adsorption isotherms, dynamic and electrophoretic light scattering, circular dichroism (CD), and isothermal titration calorimetry (ITC). A thermodynamic analysis of ITC data revealed the existence of two binding modes during protein-nanoparticle complexation. Both binding modes are driven by the cooperation of a favorable enthalpy in the presence of a dominating entropy gain. The first binding mode has a higher binding affinity, a lower equilibrium stoichiometry and is driven by a higher entropic contribution compared to the second type. The observed favorable enthalpy gain in both modes is attributed to non-covalent complexation whereas the entropy gain is associated with the re-organization of the silica surface including not only the solvent and counter ion release, but also the protein's conformational changes. Possible mechanisms are proposed to explain non-covalent complexations for each binding mode by relating the changes in the zeta potential and hydrodynamic radius to the obtained adsorption isotherms and calorimetry profile. Based on all these findings, it is proposed that lysozyme adsorption on nano-silica is the result of protein-nanoparticle and protein-protein interactions that further leads to spontaneous, non-directional and random complexation of silica through bridging flocculation. PMID:26725375

  10. A Zinc Morpholine Complex Prevents HCl/Ethanol-Induced Gastric Ulcers in a Rat Model.

    PubMed

    Salama, Suzy M; Gwaram, Nura Suleiman; AlRashdi, Ahmed S; Khalifa, Shaden A M; Abdulla, Mahmood A; Ali, Hapipah M; El-Seedi, Hesham R

    2016-01-01

    Zinc is a naturally occurring element with roles in wound healing and rescuing tissue integrity, particularly in the gastrointestinal system, where it can be detected in the mucosal and submucosal layers. Zinc chelates are known to have beneficial effects on the gastrointestinal mucosa and in cases of gastric ulcer. We synthesized complexes of zinc featuring a heterocyclic amine binding amino acids then investigated their ability to enhance the gastric self-repair. Zinc-morpholine complex, Zn(L)SCN, namely showed strong free-radical scavenging, promotion of the DNA and RNA polymerases reconstruction and suppression of cell damage. The complex's mode of action is proposed to involve hydrogen bond formation via its bis(thiocyanato-k)zinc moiety. Zn(L)SCN complex had potent effects on gastric enzymatic activity both in vitro and in vivo. The complex disrupted the ulcerative process as demonstrated by changes in the intermediate metabolites of the oxidative pathway - specifically, reduction in the MDA levels and elevation of reduced glutathione together with an attenuation of oxidative DNA damage. Additionally, Zn(L)SCN restored the gastric mucosa, inhibited the production of pro-inflammatory cytokines (IL-6, TNF and the caspases), and preserved the gastric mucous balance. Zn(L)SCN thus exhibited anti-oxidative, anti-inflammatory and anti-apoptotic activities, all of which have cytoprotective effects on the gastric lining. PMID:27460157

  11. Spectroscopic study of stripe pattern formation induced by current injection in a charge-transfer complex

    NASA Astrophysics Data System (ADS)

    Okimoto, Y.; Kumai, R.; Saitoh, E.; Izumi, M.; Horiuchi, S.; Tokura, Y.

    2004-09-01

    A stripe pattern with a spacing of a few micrometers is observed to show up on the crystal surface of a potassium 7,7’,8,8’-tetracyanoquinodimethane (K-TCNQ) upon the current-induced local insulator-metal transition. The spatially resolved reflectivity and Raman spectroscopies have shown that the stripe is a consequence of periodic phase separation with alternate dimerized and less-dimerized domains in the TCNQ stacks. The periodic modulation of the electronic state is generated in order to minimize the energy of the lattice strain, arising from the current-induced relaxation of the Peierls distortion.

  12. Path induced coherent energy transfer in light-harvesting complexes in purple bacteria

    NASA Astrophysics Data System (ADS)

    Sun, Kewei; Ye, Jun; Zhao, Yang

    2014-09-01

    Features of path dependent energy transfer in a dual-ring light-harvesting (LH2) complexes (B850) system have been examined in detail systematically. The Frenkel-Dirac time dependent variational method with the Davydov D1 Ansatz is employed with detailed evolution of polaron dynamics in real space readily obtained. It is found that the phase of the transmission amplitude through the LH2 complexes plays an important role in constructing the coherent excitonic energy transfer. It is also found that the symmetry breaking caused by the dimerization of bacteriochlorophylls and coherence or correlation between two rings will be conducive in enhancing the exciton transfer efficiency.

  13. Path induced coherent energy transfer in light-harvesting complexes in purple bacteria.

    PubMed

    Sun, Kewei; Ye, Jun; Zhao, Yang

    2014-09-28

    Features of path dependent energy transfer in a dual-ring light-harvesting (LH2) complexes (B850) system have been examined in detail systematically. The Frenkel-Dirac time dependent variational method with the Davydov D1 Ansatz is employed with detailed evolution of polaron dynamics in real space readily obtained. It is found that the phase of the transmission amplitude through the LH2 complexes plays an important role in constructing the coherent excitonic energy transfer. It is also found that the symmetry breaking caused by the dimerization of bacteriochlorophylls and coherence or correlation between two rings will be conducive in enhancing the exciton transfer efficiency. PMID:25273408

  14. Theoretical evidence of photo-induced charge transfer from DNA to intercalated ruthenium (II) organometallic complexes

    NASA Astrophysics Data System (ADS)

    Chantzis, Agisilaos; Very, Thibaut; Daniel, Chantal; Monari, Antonio; Assfeld, Xavier

    2013-07-01

    The absorption spectrum of two ruthenium (II) organometallic complexes intercalated into DNA is studied at the quantum mechanic/molecular mechanic level. The macromolecular environment is taken into account as to include geometric, electrostatic and polarization effects that can alter the excitation energy and oscillator strength. The inclusion of DNA base pairs into the quantum mechanic partition allows us for the first time to clearly evidence the presence of charge transfer excited states involving an electron withdraw from DNA base pairs to the organometallic complex.

  15. Geometrically induced complex tunnelings for ultracold atoms carrying orbital angular momentum

    NASA Astrophysics Data System (ADS)

    Polo, J.; Mompart, J.; Ahufinger, V.

    2016-03-01

    We investigate the dynamics of angular momentum states for a single ultracold atom trapped in two-dimensional systems of sided coupled ring potentials. The symmetries of the system show that tunneling amplitudes between different ring states with variation of the winding number are complex. In particular, we demonstrate that in a triangular ring configuration the complex nature of the cross-couplings can be used to geometrically engineer spatial dark states to manipulate the transport of orbital angular momentum states via quantum interference.

  16. Altered stability of etoposide-induced topoisomerase II-DNA complexes in resistant human leukaemia K562 cells.

    PubMed Central

    Ritke, M. K.; Roberts, D.; Allan, W. P.; Raymond, J.; Bergoltz, V. V.; Yalowich, J. C.

    1994-01-01

    K562 leukaemia cells were selected for resistance using 0.5 microM etoposide (VP-16). Cloned K/VP.5 cells were 30-fold resistant to growth inhibition by VP-16 and 5- to 13-fold resistant to m-AMSA, adriamycin and mitoxantrone. K/VP.5 cells did not overexpress P-glycoprotein; VP-16 accumulation was similar to that in K562 cells. VP-16-induced DNA damage was reduced in cells and nuclei from K/VP.5 cells compared with K562 cells. Topoisomerase II protein was reduced 3- to 7-fold and topoisomerase II alpha and topoisomerase II beta mRNAs were each reduced 3-fold in resistant cells. After drug removal, VP-16-induced DNA damage disappeared 1.7 times more rapidly and VP-16-induced DNA-topoisomerase II adducts dissociated 1.5 times more rapidly in K/VP.5 cells than in K562 cells. ATP (1 mM) was more effective in enhancing VP-16-induced DNA damage in nuclei isolated from sensitive cells than in nuclei from resistant cells. In addition, ATP (0.3-5 mM) stimulated VP-16-induced DNA-topoisomerase II adducts to a greater extent in K562 nuclei than in K/VP.5 nuclei. Taken together, these results indicate that resistance to VP-16 in a K562 subline is associated with a quantitative reduction in topoisomerase II protein and, in addition, a distinct qualitative alteration in topoisomerase II affecting the stability of drug-induced DNA-topoisomerase II complexes. Images Figure 5 Figure 6 Figure 7 PMID:8142256

  17. Chiral mononuclear lanthanide complexes and the field-induced single-ion magnet behaviour of a Dy analogue.

    PubMed

    Lin, Shuang-Yan; Wang, Chao; Zhao, Lang; Wu, Jianfeng; Tang, Jinkui

    2015-01-01

    Three pairs of homochiral mononuclear lanthanide complexes, with the general formula [LnH4LRRRRRR/SSSSSS(SCN)2](SCN)2·xCH3OH·yH2O(Ln = Dy (R/S-Dy1), Ho (R/S-Ho1) and Er (R/S-Er1)), have been obtained via self-assembly between chiral macrocyclic ligands and the respective thiocyanates, all of which show a saddle-type conformation with seven-coordinated metal ions. Magnetic measurements revealed that the Dy complex shows field-induced single-ion magnet behaviour, which is rarely reported in a seven-coordinated lanthanide-based SIM encapsulated in a macrocyclic ligand. The absolute configuration of all enantiomers was determined by single crystal X-ray crystallography and confirmed by electronic CD and VCD spectra. PMID:25369972

  18. Ultrasound-induced emission enhancement based on structure-dependent homo- and heterochiral aggregations of chiral binuclear platinum complexes.

    PubMed

    Komiya, Naruyoshi; Muraoka, Takako; Iida, Masayuki; Miyanaga, Maiko; Takahashi, Koichi; Naota, Takeshi

    2011-10-12

    Instant and precise control of phosphorescent emission can be performed by ultrasound-induced gelation of organic liquids with chiral, clothespin-shaped trans-bis(salicylaldiminato)Pt(II) complexes, anti-1. Nonemissive solutions of racemic, short-linked anti-1a (n = 5) and optically pure, long-linked anti-1c (n = 7) in organic liquids are transformed immediately into stable phosphorescent gels upon brief irradiation of low-power ultrasound. Emission from the gels can be controlled by sonication time, linker length, and optical activity of the complexes. Several experimental results indicated that structure-dependent homo- and heterochiral aggregations and ultrasound-control of the aggregate morphology are key factors for emission enhancement. PMID:21894951

  19. Delivery of rhBMP-2 Plasmid DNA Complexes via a PLLA/Collagen Electrospun Scaffold Induces Ectopic Bone Formation.

    PubMed

    Zhao, Xia; Komatsu, David E; Hadjiargyrou, Michael

    2016-06-01

    The development of effective strategies for gene delivery is a critical goal in DNA-based tissue engineering. Previously, our laboratory utilized the process of electrospinning to fabricate plasmid DNA-based polymeric scaffolds. Although there lease of DNA was robust, the in vitro transfection efficiency was low. In order to optimize these results, we recently modified our approach and utilized a strategy to adsorb plasmid DNA transfection complexes onto a PLLA/Collagen I electrospun scaffold for the delivery of recombinant human Bone Morphogenetic Protein-2 (rhBMP-2). BMP-2 was selected since it is currently clinically used to stimulate osteogenesis. Initially, we tested this approach using β-gal plasmid DNA complexes adsorbed onto PLLA/Collagen I scaffolds and obtained a transfection efficiency of 41% of that of the positive control (over 90%, DNA complexes in solution). Next, we utilized the same approach using the rhBMP-2 plasmid DNA complexes with the pre-osteoblastic. cell line, MC3T3, and detected robust (13-fold) expression of rhBMP-2 mRNA following transfection. Lastly, a mouse muscle pouch model was used to evaluate in vivo gene delivery efficacy and ectopic bone inducing capability of the scaffold adsorbed rhBMP-2 transfection complexes. Results showed that both rhBMP-2mRNA and protein were expressed and stimulated some ectopic bone formation. As such, adsorption of plasmid DNA complexes can be an effective strategy for tissue engineering in vivo, but further research is required to optimize our approach and obtain a clinically meaningful tissue response. PMID:27319221

  20. Collision-Induced Dissociation of Electrosprayed Protein Complexes: An All-Atom Molecular Dynamics Model with Mobile Protons.

    PubMed

    Popa, Vlad; Trecroce, Danielle A; McAllister, Robert G; Konermann, Lars

    2016-06-16

    Electrospray ionization mass spectrometry (ESI-MS) has become an indispensable technique for examining noncovalent protein complexes. Collision-induced dissociation (CID) of these multiply protonated gaseous ions usually culminates in ejection of a single subunit with a disproportionately large amount of charge. Experiments suggest that this process involves subunit unfolding prior to separation from the residual complex, as well as H(+) migration onto the unravelling chain. Molecular dynamics (MD) simulations are a promising avenue for gaining detailed insights into these CID events. Unfortunately, typical MD algorithms do not allow for mobile protons. Here we address this limitation by implementing a strategy that combines atomistic force fields (such as OPLS/AA and CHARMM36) with a proton hopping algorithm, focusing on the tetrameric complexes transthyretin and streptavidin. Protons are redistributed over all acidic and basic sites in 20 ps intervals, subject to an energy function that reflects electrostatic interactions and proton affinities. Our simulations predict that nativelike conformers at the onset of collisional heating contain multiple salt bridges. Collisional heating initially causes subtle structural changes that lead to a gradual decline of these zwitterionic patterns. Many of the MD runs show gradual unfolding of a single subunit in conjunction with H(+) migration, culminating in subunit separation from the complex. However, there are also instances where two or more chains start to unfold simultaneously, giving rise to charge competition. The scission point where the "winning" subunit separates from the complex can be attained for different degrees of unfolding, giving rise to product ions in various charge states. The simulated product ion distributions are in close agreement with experimental CID data. Proton enrichment in the departing subunit is driven by charge-charge repulsion, but the combination of salt bridge depletion, charge migration

  1. Light-induced dissociation of antenna complexes in the symbionts of scleractinian corals correlates with sensitivity to coral bleaching

    NASA Astrophysics Data System (ADS)

    Hill, R.; Larkum, A. W. D.; Prášil, O.; Kramer, D. M.; Szabó, M.; Kumar, V.; Ralph, P. J.

    2012-12-01

    Elevated temperatures in combination with moderate to high irradiance are known to cause bleaching events in scleractinian corals, characterised by damage to photosystem II (PSII). Photoprotective mechanisms of the symbiont can reduce the excitation pressure impinging upon PSII. In the bleaching sensitive species, Acropora millepora and Pocillopora damicornis, high light alone induced photoprotection through the xanthophyll cycle, increased content of the antioxidant carotenoid, β-carotene, as well as the dissociation of the light-harvesting chlorophyll complexes. The evidence is compatible with either the membrane-bound chlorophyll a-chlorophyll c 2-peridinin-protein (acpPC) complex or the peripheral peridinin-chlorophyll-protein complex, or both, disconnecting from PSII under high light. The acpPC complex potentially showed a state transition response with redistribution towards photosystem I to reduce PSII over-excitation. This apparent acpPC dissociation/reassociation was promoted by the addition of the xanthophyll cycle inhibitor, dithiothreitol, under high irradiance. Exposure to thermal stress as well as high light promoted xanthophyll de-epoxidation and increased β-carotene content, although it did not influence light-harvesting chlorophyll complex (LHC) dissociation, indicating light, rather than temperature, controls LHC dissociation. Photoinhibition was avoided in the bleaching tolerant species, Pavona decussata, suggesting xanthophyll cycling along with LHC dissociation may have been sufficient to prevent photodamage to PSII. Symbionts of P. decussata also displayed the greatest detachment of antenna complexes, while the more thermally sensitive species, Pocillopora damicornis and A. millepora, showed less LHC dissociation, suggesting antenna movement influences bleaching susceptibility.

  2. Mass Spectrometry Profiles Superoxide-Induced Intra-molecular Disulfide in the FMN-binding Subunit of Mitochondrial Complex I

    PubMed Central

    Zhang, Liwen; Xu, Hua; Chen, Chwen-Lih; Green-Church, Kari B.; Freitas, Michael A.; Chen, Yeong-Renn

    2008-01-01

    Protein thiols with regulatory functions play a critical role in maintaining the homeostasis of the redox state in mitochondria. One major host of regulatory cysteines in mitochondria is complex I, with the thiols primarily located on its 51 kDa FMN-binding subunit. In response to oxidative stress, these thiols are expected to form intra-molecular disulfide bridges as one of their oxidative post-translational modifications. Here, to test this hypothesis and gain insights into the molecular pattern of disulfide in complex I, the isolated bovine complex I was prepared. Superoxide (O2•−) is generated by complex I under the conditions of enzyme turnover. O2•−-induced intra-molecular disulfide formation at the 51 kDa subunit was determined by tandem mass spectrometry and database searching, with the latter accomplished by adaptation of the in-house developed database search engine, MassMatrix [Xu H., et. al J. Proteome Res. (2008) 7, 138–44]. LC/MS/MS analysis of tryptic/chymotryptic digests of the 51 kDa subunit from alkylated complex I revealed that four specific cysteines (C125, C142, C187, and C206) of the 51 kDa subunit were involved in the formation of mixed intra-molecular disulfide linkages. In all, three cysteine pairs were observed: C125/C142, C187/C206, and C142/C206. The formation of disulfide bond was subsequently inhibited by superoxide dismutase, indicating the involvement of O2•−. These results elucidated by mass spectrometry indicates that the residues of C125, C142, C187, and C206 are the specific regulatory cysteines of complex I, and they participate in the oxidative modification with disulfide formation under the physiological or pathophysiological conditions of oxidative stress. PMID:18789718

  3. Effects of compositional complexity on the ion-irradiation induced swelling and hardening in Ni-containing equiatomic alloys

    DOE PAGESBeta

    Jin, K.; Lu, C.; Wang, L. M.; Qu, J.; Weber, W. J.; Zhang, Y.; Bei, H.

    2016-04-14

    The impact of compositional complexity on the ion-irradiation induced swelling and hardening is studied in Ni and six Ni-containing equiatomic alloys with face-centered cubic structure. The irradiation resistance at the temperature of 500 °C is improved by controlling the number and, especially, the type of alloying elements. Alloying with Fe and Mn has a stronger influence on swelling reduction than does alloying with Co and Cr. Lastly, the quinary alloy NiCoFeCrMn, with known excellent mechanical properties, has shown 40 times higher swelling tolerance than nickel.

  4. Induced Circular Dichroism in Phosphine Gold(I) Aryl Acetylide Urea Complexes through Hydrogen-Bonded Chiral Co-Assemblies.

    PubMed

    Dubarle-Offner, Julien; Moussa, Jamal; Amouri, Hani; Jouvelet, Benjamin; Bouteiller, Laurent; Raynal, Matthieu

    2016-03-14

    Phosphine gold(I) aryl acetylide complexes equipped with a central bis(urea) moiety form 1D hydrogen-bonded polymeric assemblies in solution that do not display any optical activity. Chiral co-assemblies are formed by simple addition of an enantiopure (metal-free) complementary monomer. Although exhibiting an intrinsically achiral linear geometry, the gold(I) aryl acetylide fragment is located in the chiral environment displayed by the hydrogen-bonded co-assemblies, as demonstrated by induced circular dichroism (ICD). PMID:26780877

  5. Surface-enhanced Raman scattering spectroscopy of topotecan-DNA complexes: Binding to DNA induces topotecan dimerization

    NASA Astrophysics Data System (ADS)

    Mochalov, K. E.; Strel'Tsov, S. A.; Ermishov, M. A.; Grokhovskii, S. L.; Zhuze, A. L.; Ustinova, O. A.; Sukhanova, A. V.; Nabiev, I. R.; Oleinikov, V. A.

    2002-09-01

    The interaction of topotecan (TPT), antitumor inhibitor of human DNA topoisomerase I, with calf thymus DNA was studied by surface-enhanced Raman scattering (SERS) spectroscopy. The SERS spectra of TPT are found to depend on its concentration in solution, which is associated with the dimerization of TPT. The spectral signatures of dimerization are identified. It is shown that binding to DNA induces the formation of TPT dimers. The formation of DNA-TPT-TPT-DNA complexes is considered as one of the possible mechanisms of human DNA topoisomerase I inhibition.

  6. Distribution of Chlorophyll-Protein Complexes during Chilling in the Light Compared with Heat-Induced Modifications 1

    PubMed Central

    Ovaska, Jari; Mäenpää, Pirkko; Nurmi, Arja; Aro, Eva-Mari

    1990-01-01

    The effects of chilling in the light (4 days at 5°C and 100-200 micromoles of photons per square meter per second) on the distribution of chlorophyll (Chl) protein complexes between appressed and nonappressed thylakoid regions of pumpkin (Cucurbita pepo L.) chloroplasts were studied and compared with the changes occurring during in vitro heat treatment (5 minutes at 40°C) of isolated thylakoids. Both treatments induced an increase (18 and 65%, respectively) in the relative amount of the antenna Chl a protein complexes (CP47 + CP43) of photosystem II (PSII) in stroma lamellae vesicles. Freeze-fracture replicas of light-chilled material revealed an increase in the particle density on the exoplasmic fracture face of unstacked membrane regions. These two treatments differed markedly, however, in respect to comigration of the light-harvesting Chl a/b protein complex (LHCII) of PSII. The LHCII/PSII ratio in stroma lamellae vesicles remained fairly constant during chilling in the light, whereas it dropped during the heat treatment. Moreover, it was a minor light-harvesting Chl a/b protein complex of PSII, CP29, that increased most in stroma lamellae vesicles during light-chilling. Changes in the organization of LHCII during chilling were suggested by a shift to particles of smaller sizes on the protoplasmic fracture face of stacked membrane regions and a decrease in the amount of trans-Δ3-hexadecenoic acid in the phosphatidyldiacylglycerol fraction. Images Figure 2 PMID:16667464

  7. A Zinc Morpholine Complex Prevents HCl/Ethanol-Induced Gastric Ulcers in a Rat Model

    PubMed Central

    Salama, Suzy M.; Gwaram, Nura Suleiman; AlRashdi, Ahmed S.; Khalifa, Shaden A. M.; Abdulla, Mahmood A.; Ali, Hapipah M.; El-Seedi, Hesham R.

    2016-01-01

    Zinc is a naturally occurring element with roles in wound healing and rescuing tissue integrity, particularly in the gastrointestinal system, where it can be detected in the mucosal and submucosal layers. Zinc chelates are known to have beneficial effects on the gastrointestinal mucosa and in cases of gastric ulcer. We synthesized complexes of zinc featuring a heterocyclic amine binding amino acids then investigated their ability to enhance the gastric self-repair. Zinc-morpholine complex, Zn(L)SCN, namely showed strong free-radical scavenging, promotion of the DNA and RNA polymerases reconstruction and suppression of cell damage. The complex’s mode of action is proposed to involve hydrogen bond formation via its bis(thiocyanato-k)zinc moiety. Zn(L)SCN complex had potent effects on gastric enzymatic activity both in vitro and in vivo. The complex disrupted the ulcerative process as demonstrated by changes in the intermediate metabolites of the oxidative pathway – specifically, reduction in the MDA levels and elevation of reduced glutathione together with an attenuation of oxidative DNA damage. Additionally, Zn(L)SCN restored the gastric mucosa, inhibited the production of pro-inflammatory cytokines (IL-6, TNF and the caspases), and preserved the gastric mucous balance. Zn(L)SCN thus exhibited anti-oxidative, anti-inflammatory and anti-apoptotic activities, all of which have cytoprotective effects on the gastric lining. PMID:27460157

  8. Photo-induced DNA cleavage and cytotoxicity of a ruthenium(II) arene anticancer complex.

    PubMed

    Brabec, Viktor; Pracharova, Jitka; Stepankova, Jana; Sadler, Peter J; Kasparkova, Jana

    2016-07-01

    We report DNA cleavage by ruthenium(II) arene anticancer complex [(η(6)-p-terp)Ru(II)(en)Cl](+) (p-terp=para-terphenyl, en=1,2-diaminoethane, complex 1) after its photoactivation by UVA and visible light, and the toxic effects of photoactivated 1 in cancer cells. It was shown in our previous work (T. Bugarcic et al., J. Med. Chem. 51 (2008) 5310-5319) that this complex exhibits promising toxic effects in several human tumor cell lines and concomitantly its DNA binding mode involves combined intercalative and monofunctional (coordination) binding modes. We demonstrate in the present work that when photoactivated by UVA or visible light, 1 efficiently photocleaves DNA, also in hypoxic media. Studies of the mechanism underlying DNA cleavage by photoactivated 1 reveal that the photocleavage reaction does not involve generation of reactive oxygen species (ROS), although contribution of singlet oxygen ((1)O2) to the DNA photocleavage process cannot be entirely excluded. Notably, the mechanism of DNA photocleavage by 1 appears to involve a direct modification of mainly those guanine residues to which 1 is coordinatively bound. As some tumors are oxygen-deficient and cytotoxic effects of photoactivated ruthenium compounds containing {Ru(η(6)-arene)}(2+) do not require the presence of oxygen, this class of ruthenium complexes may be considered potential candidate agents for improved photodynamic anticancer chemotherapy. PMID:26778426

  9. Binuclear bromide complex of Bi(III): Thermally induced changes in optical properties

    NASA Astrophysics Data System (ADS)

    Adonin, Sergey A.; Sokolov, Maxim N.; Rakhmanova, Marianna E.; Smolentsev, Anton I.; Pishchur, Denis P.; Korolkov, Ilya V.; Kozlova, Svetlana G.; Fedin, Vladimir P.

    2016-05-01

    Binuclear bromobismuthate complex (H2bipy)2[Bi2Br10] (1) displays the optical properties: 1) thermochromism, 2) disappearance/appearance of luminescence at 298/77 K. To investigate this feature, a combination of X-ray diffractometry, differential scanning calorimetry (DSC) and quantum chemical calculations has been used.

  10. Solvent induced helical aggregation in the self-assembly of cholesterol tailed platinum complexes.

    PubMed

    Mao, Yueyuan; Liu, Keyin; Meng, Luyan; Chen, Liang; Chen, Liming; Yi, Tao

    2014-10-14

    Three alkynylplatinum(ii) bipyridyl complexes in which two cholesterol groups are combined with a bipyridyl group via alkyl chains and amido bonds were designed and synthesized. The complexes have different lengths of ethylene glycol chains at the para-position of 1-phenylethyne. All three complexes can self-assemble to gel networks in DMSO, while only the morphology of 1a without an ether chain shows a well-defined right-handed helical structure in layer packing mode. However, 1c with long ethylene glycol chains forms perfect regular left-handed helical structures in aqueous ethanol solution while the volume percentage of water is less than 5% (v/v). As the ratio of water increases, the chirality changes from a left-handed helix to a right-handed helix and the packing mode alters from a monolayer structure to a hexagonal structure. As the ratio of water further increases to greater than 50% (v/v), the structure of the assembly finally transforms into bilayer vesicles. The process of the morphology transition is traced by circular dichroism spectra, powder X-ray diffraction, SEM and TEM images. The result indicates that a polar solvent (water) acts as a trigger to change the self-assembly of the chiral structures of the complex due to the strong hydrophobic interaction between cholesterol groups and the balance of the hydrophobicity and hydrophilicity of the solvent environment. PMID:25131259

  11. Bismuth induced enhanced green emission from terbium ions and their complex in thin films.

    PubMed

    Kaur, Gagandeep; Kumar, Brijesh; Verma, R K; Rai, S B

    2014-07-28

    Bismuth nanoparticles (NPs) have been prepared by the pulsed laser ablation technique using the third harmonics of a Nd-YAG laser. UV-absorption and TEM micrographs show Bi NPs of spherical shape with the average particle size ranging from 15 to 20 nm. These NPs were dispersed with Tb(3+) ions and their complex with salicylic acid (Sal) in polyvinyl alcohol to obtain thin films. The influence of Bi NPs on the emissive properties of Tb(3+) ions and the [Tb(Sal)3(phen)] complex has been studied by luminescence spectroscopy using 266 nm and 355 nm as excitation wavelengths. The luminescence intensity of Tb(3+) ions complexed with Sal in the thin polymer films increased significantly as compared to the Tb(3+) ions in the presence of Bi NPs on excitation at 355 nm. However, terbium ions in the case of the [Tb(Sal)3(phen)] complex together with NPs show an intense and extended emission spectrum in the 375-700 nm range for transitions arising from (5)D3 and (5)D4 levels to different (7)F(J) levels on 266 nm excitation. The luminescence enhancement has also been supported by lifetime measurements. PMID:24911968

  12. X-ray-induced cell death in the developing hippocampal complex involved neurons and requires protein synthesis

    SciTech Connect

    Ferrer, I.; Serrano, T.; Alcantara, S.; Tortosa, A.; Graus, F.

    1993-07-01

    Sprague-Dawley rats aged 1 or 15 days were irradiated with a single dose of 200 cGy X-rays and killed at different intervals from 3 to 48 hours (h). Dying cells were recognized by their shrunken and often fragmented nuclei and less damaged cytoplasm in the early stages. On the basis of immunocytochemical markers, dying cells probably represented a heterogeneous population which included neurons and immature cells. In rats aged 1 day the number of dying cells rapidly increased in the hippocampal complex with peak values 6 h after irradiation. This was following by a gentle decrease to reach normal values 48 h after irradiation. The most severely affected regions were the subplate and the cellular layer of the subiculum, gyrus dentatus and hilus, and the stratum oriens and pyramidale of the hippocampus (CA1 more affected than CA2, and this more affected than CA3). X-ray-induced cell death was abolished with an injection of cycloheximide (2 [mu]g/g i.p.) given at the time of irradiation. X-ray-induced cell death was not changed after the intraventicular administration of nerve growth factor (NGF; 10 [mu]g in saline) at the time of irradiation. Cell death was not induced by X-irradiation in rats aged 15 days. These results indicate that X-ray-induced cell death in the hippocampal complex of the developing rat is subjected to determinate temporal and regional patterns of vulnerability; it is an active process mediated by protein synthesis but probably not dependent on NGF. 60 refs., 5 figs.

  13. Focal adhesion kinase (FAK) phosphorylation is not required for genistein-induced FAK-beta-1-integrin complex formation.

    PubMed

    Liu, Y; Kyle, E; Lieberman, R; Crowell, J; Kellof, G; Bergan, R C

    2000-01-01

    It has previously been shown that changes in the activity of focal adhesion kinase (FAK), and its binding to beta-1-integrin, accompany genistein-induced adhesion of prostate cells. Consumption of genistein world wide is associated with a lower incidence of metastatic prostate cancer. Early human clinical trials of genistein are under way to evaluate genistein's potential causal role in this regard. Though an important cell adhesion-associated signaling molecule, FAK's role in regulating prostate cell adhesion was not clear. Elucidation of this process would provide important information relating to both biology and potential clinical endpoints. It was hypothesized that FAK activation and complex formation are temporally related in prostate cells, and can thus be separated. Significant activation of FAK was demonstrated when cells adhered to fibronectin, as compared to poly-L-lysine, thus demonstrating that beta-1-integrin plays a significant role in activating FAK. Neither FAK activation, nor FAK-integrin complex formation, required beta-1-integrin ligand. However, disruption of the cellular cytoskeleton by cytochalasin D prevented FAK activation, but did not block genistein-induced complex formation. In the face of a disrupted cytoskeleton, signaling through FAK could not be restored through either integrin cross linking, or re-establishment of tensile forces via attachment to solid matrix. These studies demonstrate that FAK-beta-1-integrin complex formation does not require FAK activation, suggesting that it is an early event in prostate cell adhesion. An intact cytoskeleton is necessary for FAK activation. The functional importance of beta-1-integrin in prostate cells is demonstrated. Current findings support plans to test genistein in prostate cancer. PMID:11315093

  14. Ruthenium Dihydroxybipyridine Complexes are Tumor Activated Prodrugs Due to Low pH and Blue Light Induced Ligand Release

    PubMed Central

    Hufziger, Kyle T.; Thowfeik, Fathima Shazna; Charboneau, David J.; Nieto, Ismael; Dougherty, William G.; Kassel, W. Scott; Dudley, Timothy J.; Merino, Edward J.; Papish, Elizabeth T.; Paul, Jared J.

    2013-01-01

    Ruthenium drugs are potent anti-cancer agents, but inducing drug selectivity and enhancing their modest activity remain challenging. Slow Ru ligand loss limits the formation of free sites and subsequent binding to DNA base pairs. Herein, we designed a ligand that rapidly dissociates upon irradiation at low pH. Activation at low pH can lead to cancer selectivity, since many cancer cells have higher metabolism (and thus lower pH) than non-cancerous cells. We have used the pH sensitive ligand, 6,6′-dihydroxy-2,2′-bipyridine (66′bpy(OH)2), to generate [Ru(bpy)2(66′(bpy(OH)2)]2+, which contains two acidic hydroxyl groups with pKa1 = 5.26 and pKa2 = 7.27. Irradiation when protonated leads to photo-dissociation of the 66′bpy(OH)2 ligand. An in-depth study of the structural and electronic properties of the complex was carried out using X-Ray crystallography, electrochemistry, UV/visible spectroscopy, and computational techniques. Notably, Ru-N bond lengths in the 66′bpy(OH)2 complex are longer (by ~0.3 Å) than in polypyridyl complexes that lack 6 and 6′ substitution. Thus, the longer bond length predisposes the complex for photo-dissociation and leads to the anti-cancer activity. When the complex is deprotonated, the 66′bpy(O−)2 ligand molecular orbitals mix heavily with the ruthenium orbitals, making new mixed metal-ligand orbitals that lead to a higher bond order. We investigated the anti-cancer activities of [Ru(bpy)2(66′(bpy(OH)2)]2+, [Ru(bpy)2(44′(bpy(OH)2)]2+, and [Ru(bpy)3]2+ (44′(bpy(OH)2 = 4,4′-dihydroxy-2,2′-bipyridine) in HeLa cells, which have a relatively low pH. It is found that [Ru(bpy)2(66′(bpy(OH)2)]2+ is more cytotoxic than the other ruthenium complexes studied. Thus, we have identified a pH sensitive ruthenium scaffold that can be exploited for photo-induced anti-cancer activity. PMID:24184694

  15. Iminophosphorane-organogold(III) complexes induce cell death through mitochondrial ROS production

    PubMed Central

    Vela, Laura; Contel, María; Palomera, Luis; Azaceta, Gemma; Marzo, Isabel

    2011-01-01

    Gold compounds are being investigated as potential antitumor drugs. Some gold(III) derivatives have shown to induce cell death in solid tumors but their mechanism of action differs from that of cisplatin, since most of these compounds do not bind to DNA. We have explored cellular events triggered by three different iminophosphorane-organo gold(III) compounds in leukemia cells (a neutral compound with two chloride ligands [Au{κ2-C,N-C6H4(PPh2=N(C6H5)-2}Cl2] 1, and two cationic compounds with either a dithiocarbamate ligand [Au{κ2-C,N-C6H4(PPh2=N(C6H5)-2}(S2CN-Me2)]PF6 2, or a water-soluble phosphine and a chloride ligand [Au{κ2-C,N-C6H4(PPh2=N(C6H5)-2}(P{Cp(m-C6H4-SO3Na)2}3) Cl]PF6 3). All three compounds showed higher toxicity against leukemia cells when compared to normal T-lymphocytes. Compounds 1 and 2 induced both necrosis and apoptosis, while 3 was mainly apoptotic. Necrotic cell death induced by 1 and 2 was Bax/Bak- and caspase-independent, while apoptosis induced by 3 was Bax/Bak-dependent. Reactive oxygen species (ROS) production at the mitochondrial level was a critical step in the antitumor effect of these compounds. PMID:21864808

  16. Iminophosphorane-organogold(III) complexes induce cell death through mitochondrial ROS production.

    PubMed

    Vela, Laura; Contel, María; Palomera, Luis; Azaceta, Gemma; Marzo, Isabel

    2011-10-01

    Gold compounds are being investigated as potential antitumor drugs. Some gold(III) derivatives have been shown to induce cell death in solid tumors but their mechanism of action differs from that of cisplatin, since most of these compounds do not bind to DNA. We have explored cellular events triggered by three different iminophosphorane-organogold(III) compounds in leukemia cells (a neutral compound with two chloride ligands [Au{κ(2)-C,N-C(6)H(4)(PPh(2)=N(C(6)H(5))-2}Cl(2)] 1, and two cationic compounds with either a dithiocarbamate ligand [Au{κ(2)-C,N-C(6)H(4)(PPh(2)=N(C(6)H(5))-2}(S(2)CN-Me(2))]PF(6)2, or a water-soluble phosphine and a chloride ligand [Au{κ(2)-C,N-C(6)H(4)(PPh(2)=N(C(6)H(5))-2}(P{Cp(m-C(6)H(4)-SO(3)Na)(2)}(3)) Cl]PF(6)3). All three compounds showed higher toxicity against leukemia cells when compared to normal T-lymphocytes. Compounds 1 and 2 induced both necrosis and apoptosis, while 3 was mainly apoptotic. Necrotic cell death induced by 1 and 2 was Bax/Bak- and caspase-independent, while apoptosis induced by 3 was Bax/Bak-dependent. Reactive oxygen species (ROS) production at the mitochondrial level was a critical step in the antitumor effect of these compounds. PMID:21864808

  17. Suppression of tumor growth by designed dimeric epidithiodiketopiperazine targeting hypoxia-inducible transcription factor complex.

    PubMed

    Dubey, Ramin; Levin, Michael D; Szabo, Lajos Z; Laszlo, Csaba F; Kushal, Swati; Singh, Jason B; Oh, Philip; Schnitzer, Jan E; Olenyuk, Bogdan Z

    2013-03-20

    Hypoxia is a hallmark of solid tumors, is associated with local invasion, metastatic spread, resistance to chemo- and radiotherapy, and is an independent, negative prognostic factor for a diverse range of malignant neoplasms. The cellular response to hypoxia is primarily mediated by a family of transcription factors, among which hypoxia-inducible factor 1 (HIF1) plays a major role. Under normoxia, the oxygen-sensitive α subunit of HIF1 is rapidly and constitutively degraded but is stabilized and accumulates under hypoxia. Upon nuclear translocation, HIF1 controls the expression of over 100 genes involved in angiogenesis, altered energy metabolism, antiapoptotic, and pro-proliferative mechanisms that promote tumor growth. A designed transcriptional antagonist, dimeric epidithiodiketopiperazine (ETP 2), selectively disrupts the interaction of HIF1α with p300/CBP coactivators and downregulates the expression of hypoxia-inducible genes. ETP 2 was synthesized via a novel homo-oxidative coupling of the aliphatic primary carbons of the dithioacetal precursor. It effectively inhibits HIF1-induced activation of VEGFA, LOX, Glut1, and c-Met genes in a panel of cell lines representing breast and lung cancers. We observed an outstanding antitumor efficacy of both (±)-ETP 2 and meso-ETP 2 in a fully established breast carcinoma model by intravital microscopy. Treatment with either form of ETP 2 (1 mg/kg) resulted in a rapid regression of tumor growth that lasted for up to 14 days. These results suggest that inhibition of HIF1 transcriptional activity by designed dimeric ETPs could offer an innovative approach to cancer therapy with the potential to overcome hypoxia-induced tumor growth and resistance. PMID:23448368

  18. A luminescent heptanuclear DyIr6 complex showing field-induced slow magnetization relaxation.

    PubMed

    Zeng, Dai; Ren, Min; Bao, Song-Song; Li, Li; Zheng, Li-Min

    2014-08-01

    The first example of iridium/lanthanide phosphonates, i.e. [DyIr6(ppy)12(bpp)2(bppH)4](CF3SO3)·8H2O (1) (ppy(-) = 2-phenylpyridine, bpp(2-) = 2-pyridylphosphonate) is reported. It shows dual functions with the photoluminescence and field-induced slow magnetization relaxation originating from the Ir and Dy moieties, respectively. PMID:24942060

  19. Photoluminescence analysis of self induced planer alignment in azo dye dispersed nematic liquid crystal complex

    SciTech Connect

    Kumar, Rishi Sood, Srishti Raina, K. K.

    2014-04-24

    We have developed azo dye doped nematic liquid crystal complex for advanced photonic liquid crystal display technology aspects. Disperse orange azo dye self introduced planer alignment in the nematic liquid crystal without any surface anchoring treatment. Planer alignment was characterized by optical polarizing microscopy. The electro-optical switching response of dye disperse planer aligned nematic cell was investigated as a function of applied voltage with the help of photoluminescence spectrophotometer for the tuning of photoluminescence contrast.

  20. Self-Induced Switchings between Multiple Space-Time Patterns on Complex Networks of Excitable Units

    NASA Astrophysics Data System (ADS)

    Ansmann, Gerrit; Lehnertz, Klaus; Feudel, Ulrike

    2016-01-01

    We report on self-induced switchings between multiple distinct space-time patterns in the dynamics of a spatially extended excitable system. These switchings between low-amplitude oscillations, nonlinear waves, and extreme events strongly resemble a random process, although the system is deterministic. We show that a chaotic saddle—which contains all the patterns as well as channel-like structures that mediate the transitions between them—is the backbone of such a pattern-switching dynamics. Our analyses indicate that essential ingredients for the observed phenomena are that the system behaves like an inhomogeneous oscillatory medium that is capable of self-generating spatially localized excitations and that is dominated by short-range connections but also features long-range connections. With our findings, we present an alternative to the well-known ways to obtain self-induced pattern switching, namely, noise-induced attractor hopping, heteroclinic orbits, and adaptation to an external signal. This alternative way can be expected to improve our understanding of pattern switchings in spatially extended natural dynamical systems like the brain and the heart.

  1. Anti-diabetic effects of a series of vanadium dipicolinate complexes in rats with streptozotocin-induced diabetes.

    PubMed

    Willsky, Gail R; Chi, Lai-Har; Godzala, Michael; Kostyniak, Paul J; Smee, Jason J; Trujillo, Alejandro M; Alfano, Josephine A; Ding, Wenjin; Hu, Zihua; Crans, Debbie C

    2011-10-01

    The effects of oral treatment of rats with streptozotocin-induced diabetes with a range of vanadium dipicolinate complexes (Vdipic) and derivatives are reviewed. Structure-reactivity relationships are explored aiming to correlate properties such as stability, to their insulin-enhancing effects. Three types of modifications are investigated; first, substitutions on the aromatic ring, second, coordination of a hydroxylamido group to the vanadium, and third, changes in the oxidation state of the vanadium ion. These studies allowed us to address the importance of coordination chemistry, and redox chemistry, as modes of action. Dipicolinate was originally chosen as a ligand because the dipicolinatooxovanadium(V) complex (V5dipic), is a potent inhibitor of phosphatases. The effect of vanadium oxidation state (3, 4 or 5), on the insulin-enhancing properties was studied in both the Vdipic and VdipicCl series. Effects on blood glucose, body weight, serum lipids, alkaline phosphatase and aspartate transaminase were selectively monitored. Statistically distinct differences in activity were found, however, the trends observed were not the same in the Vdipic and VdipicCl series. Interperitoneal administration of the Vdipic series was used to compare the effect of administration mode. Correlations were observed for blood vanadium and plasma glucose levels after V5dipic treatment, but not after treatment with corresponding V4dipic and V3dipic complexes. Modifications of the aromatic ring structure with chloride, amine or hydroxyl groups had limited effects. Global gene expression was measured using Affymetrix oligonucleotide chips. All diabetic animals treated with hydroxyl substituted V5dipic (V5dipicOH) and some diabetic rats treated with vanadyl sulfate had normalized hyperlipidemia yet uncontrolled hyperglycemia and showed abnormal gene expression patterns. In contrast to the normal gene expression profiles previously reported for some diabetic rats treated with vanadyl

  2. Stress-Induced Nitrogen and Oxygen Segregation and Complexing Investigated by High Resolution Synchrotron FTIR: Preprint

    SciTech Connect

    Karoui, A.; Buonassisi, T.; Sahtout Karoui, F.; Rozgonyi, G. A.; Michael, M.; Weber, E. R.; Ciszek, T. F.

    2004-08-01

    Nitrogen doped Czochralski (N-CZ) and Float Zone (N-FZ) silicon were measured by high resolution synchrotron Fourier Transform IR spectroscopy (HR-FTIR). The chemical complexes were analyzed in specific regions with known extended defects, i.e., denuded or precipitated regions of annealed N-CZ Si wafers, in N-FZ Si with ring defects and on ''N-Skin'' region. The absorption lines were assigned to chemical complexes previously studied by first principles calculations. In annealed N-CZ Si wafers, a strong correlation was observed between the absorption line intensity depth variations and the defect distributions revealed by an Oxygen Precipitate Profiler (OPP), and oxygen and nitrogen SIMS profiles. Transformation of chemical complexes from one type to another was observed. A defect band, visible as an OPP peak at the denuded zone-bulk interface was found to be related to vacancy defect enhancement of oxygen precipitation via production of mobile N2. For the as grown N-FZ, the radial dependency of IR absorption line intensity is correlated to x-ray topography contrast.

  3. Proteomic response of β-lactamases-producing Enterobacter cloacae complex strain to cefotaxime-induced stress.

    PubMed

    Maravić, Ana; Cvjetan, Svjetlana; Konta, Marina; Ladouce, Romain; Martín, Fernando A

    2016-07-01

    Bacteria of the Enterobacter cloacae complex are among the ten most common pathogens causing nosocomial infections in the USA. Consequently, increased resistance to β-lactam antibiotics, particularly expanded-spectrum cephalosporins like cefotaxime (CTX), poses a serious threat. Differential In-Gel Electrophoresis (DIGE), followed by LC-MS/MS analysis and bioinformatics tools, was employed to investigate the survival mechanisms of a multidrug-resistant E. hormaechei subsp. steigerwaltii 51 carrying several β-lactamase-encoding genes, including the 'pandemic' blaCTX-M-15 After exposing the strain with sub-minimal inhibitory concentration (MIC) of CTX, a total of 1072 spots from the whole-cell proteome were detected, out of which 35 were differentially expressed (P ≤ 0.05, fold change ≥1.5). Almost 50% of these proteins were involved in cell metabolism and energy production, and then cell wall organization/virulence, stress response and transport. This is the first study investigating the whole-cell proteomic response related to the survival of β-lactamases-producing strain, belonging to the E. cloacae complex when exposed to β-lactam antibiotic. Our data support the theory of a multifactorial synergistic effect of diverse proteomic changes occurring in bacterial cells during antibiotic exposure, depicting the complexity of β-lactam resistance and giving us an insight in the key pathways mediating the antibiotic resistance in this emerging opportunistic pathogen. PMID:27162211

  4. Natural variation in small molecule-induced TIR-NB-LRR signaling induces root growth arrest via EDS1- and PAD4-complexed R protein VICTR in Arabidopsis.

    PubMed

    Kim, Tae-Houn; Kunz, Hans-Henning; Bhattacharjee, Saikat; Hauser, Felix; Park, Jiyoung; Engineer, Cawas; Liu, Amy; Ha, Tracy; Parker, Jane E; Gassmann, Walter; Schroeder, Julian I

    2012-12-01

    In a chemical genetics screen we identified the small-molecule [5-(3,4-dichlorophenyl)furan-2-yl]-piperidine-1-ylmethanethione (DFPM) that triggers rapid inhibition of early abscisic acid signal transduction via PHYTOALEXIN DEFICIENT4 (PAD4)- and ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1)-dependent immune signaling mechanisms. However, mechanisms upstream of EDS1 and PAD4 in DFPM-mediated signaling remain unknown. Here, we report that DFPM generates an Arabidopsis thaliana accession-specific root growth arrest in Columbia-0 (Col-0) plants. The genetic locus responsible for this natural variant, VICTR (VARIATION IN COMPOUND TRIGGERED ROOT growth response), encodes a TIR-NB-LRR (for Toll-Interleukin1 Receptor-nucleotide binding-Leucine-rich repeat) protein. Analyses of T-DNA insertion victr alleles showed that VICTR is necessary for DFPM-induced root growth arrest and inhibition of abscisic acid-induced stomatal closing. Transgenic expression of the Col-0 VICTR allele in DFPM-insensitive Arabidopsis accessions recapitulated the DFPM-induced root growth arrest. EDS1 and PAD4, both central regulators of basal resistance and effector-triggered immunity, as well as HSP90 chaperones and their cochaperones RAR1 and SGT1B, are required for the DFPM-induced root growth arrest. Salicylic acid and jasmonic acid signaling pathway components are dispensable. We further demonstrate that VICTR associates with EDS1 and PAD4 in a nuclear protein complex. These findings show a previously unexplored association between a TIR-NB-LRR protein and PAD4 and identify functions of plant immune signaling components in the regulation of root meristematic zone-targeted growth arrest. PMID:23275581

  5. The thioxotriazole copper(II) complex A0 induces endoplasmic reticulum stress and paraptotic death in human cancer cells.

    PubMed

    Tardito, Saverio; Isella, Claudio; Medico, Enzo; Marchiò, Luciano; Bevilacqua, Elena; Hatzoglou, Maria; Bussolati, Ovidio; Franchi-Gazzola, Renata

    2009-09-01

    The copper(II) complex A0 induces a type of non-apoptotic cell death also known as paraptosis. Paraptosis involves extensive endoplasmic reticulum vacuolization in the absence of caspase activation. A wide panel of human cancer cell lines was used to demonstrate differences in cytotoxicity by the paraptosis-inducing drug A0 and the metal-based pro-apoptotic drug cisplatin. Gene expression profiling of the human fibrosarcoma HT1080 cells showed that, while cisplatin induced p53 targets, A0 up-regulated genes involved in the unfolded protein response (UPR) and response to heavy metals. The cytotoxic effects of A0 were associated with inhibition of the ubiquitin-proteasome system and accumulation of ubiquitinylated proteins, in a manner dependent on protein synthesis. Cycloheximide inhibited the accumulation of ubiquitinylated proteins and hampered A0-induced cell death process. The occurrence of the UPR during A0-induced death process was shown by the increased abundance of spliced XBP1 mRNA, transient eIF2alpha phosphorylation, and a series of downstream events, including attenuation of global protein synthesis and increased expression of ATF4, CHOP, BIP, and GADD34. Mouse embryonic fibroblasts expressing a mutant eIF2alpha, which could not be phosphorylated, were more resistant to A0 than wild type cells, pointing to a pro-death role of eIF2alpha phosphorylation. A0 may thus represent the prototypical member of a new class of compounds that cause paraptotic cell death via mechanisms involving eIF2alpha phosphorylation and the UPR. PMID:19561079

  6. A Role of Low-angle Thrust Fault for the Occurrence of rain-induced Rockslides in an Accretionary Complex

    NASA Astrophysics Data System (ADS)

    Arai, N.; Chigira, M.

    2015-12-01

    Recently, extreme weather related to global warming occurs frequently all over the world; there have been many record-setting rainfall events. Accordingly, potential of rain-induced rockslides increases. Examples of recent rain-induced rock avalanches with tens or more than a hundred of fatalities are a rockslide in Shiaolin village, Taiwan by 2009 Typhoon Morakot, and rockslides induced by 2011 typhoon Talas in Japan. However, the method to predict potential sites of rockslides is not established. Geological causes of rockslides are site specific and they must be clarified for each case. 2011 Typhoon Talas induced more than 50 rockslides in the outer belt of the Southwest Japan, where is underlain by Cretaceous - lower Miocene accretionary complexes. We performed thorough geological mapping in the Akatani area, where two huge rockslides occurred with volumes of 2 million and 8 million m3 respectively. As a result, we found that these two rockslides had their sliding surfaces along a low-angle-thrust with a dip of 29°~40° extending more than 5 km, which fault we name Kawarabi-thrust. This thrust has a fracture zone of 6.0 m in the maximum width, composed of clayey fault breccia with a few layers of black gouges. These fault materials are very weak and impermeable, so the fracture zone is expected to prevent the groundwater filtration and build up the pore pressure. This thrust had been exposed along the riversides at the foot of the two rockslides, which suggests that the slopes on the thrust had been destabilized by the undercutting of long-term river incision. The destabilization induced gravitational slope deformation with small scarps before the catastrophic failure. Our finding suggests that locating a large-scale low-angle-thrust is essentially important to predict potential sites of catastrophic rockslides as well as interpreting the internal structure of gravitationally deformed slopes.

  7. Meta-Analysis of Prognostic Implications of Exercise-Induced Ventricular Premature Complexes in the General Population.

    PubMed

    Kim, Joonseok; Kwon, Minkyung; Chang, Jinsoo; Harris, David; Gerson, Myron C; Hwang, Seung-Sik; Oh, Seung-Won

    2016-09-01

    Ventricular premature complexes (VPCs) during stress testing in the general population are commonly seen in clinical practice, but their prognostic value is not well understood. A comprehensive literature search of MEDLINE, Embase, and the Cochrane Library from January 1970 to May 2015 was conducted. Observational cohort studies on general populations evaluating the association between exercise-induced VPCs and all-cause or cardiovascular mortality were included in the analysis. Nine studies comprising 62,488 participants comparing clinical outcomes of patients with and without exercise-induced VPCs were included. The overall combined relative risks (RRs) for all-cause mortality and cardiovascular mortality in patients with exercise-induced VPCs were 1.41 (95% CI 1.23 to 1.61) and 1.86 (95% CI 1.51 to 2.30), respectively. In subgroup analysis, both frequent VPCs (RR 1.35, 95% CI 1.14 to 1.60) and infrequent VPCs (RR 1.57, 95% CI 1.13 to 2.18) were associated with an adverse outcome. VPCs during recovery were associated with an increased risk of death (RR 1.55, 95% CI 1.22 to 1.96). VPCs during exercise did not achieve statistical significance (RR 1.14, 95% CI 0.96 to 1.34), but only a few studies were included in the analysis. In conclusion, our meta-analysis suggests that exercise-induced VPCs in the general population significantly increase the risk of total mortality and cardiovascular mortality. Our study calls for further studies to assess the prognostic significance of exercise-induced VPCs and the utility of efforts to reduce the VPC burden to improve the clinical outcome. PMID:27394411

  8. Immune-stimulating complexes as adjuvants for inducing local and systemic immunity after oral immunization with protein antigens.

    PubMed Central

    Mowat, A M; Maloy, K J; Donachie, A M

    1993-01-01

    Orally active synthetic vaccines containing purified antigens would have many benefits for immunizing against systemic and mucosal diseases. However, several factors have limited the development of such vaccines, including the poor immunogenicity of purified proteins and their usual ability to induce tolerance when given orally. Here, we show that incorporation of ovalbumin (OVA) into immune-stimulating complexes (ISCOMS) containing saponin prevents the induction of oral tolerance in mice. In parallel, the spleen and mesenteric lymph node of mice fed OVA ISCOMS are primed for class I major histocompatibility complex (MHC)-restricted cytotoxic T-cell activity which recognizes physiologically processed epitopes on OVA. Oral immunization with OVA ISCOMS also stimulates high secretory IgA antibody responses in the intestine itself, as well as serum IgG antibodies. None of these active immune responses are detectable in mice fed OVA alone. Despite the potent priming of mucosal priming by OVA ISCOMS, re-exposure to antigen does not induce the intestinal immunopathology found in other systems after the breakdown of oral tolerance. Thus, ISCOMS have several unique properties as vectors for oral immunization and could provide a basis for future mucosal vaccines. PMID:7508416

  9. In vitro platelet activation, aggregation and platelet-granulocyte complex formation induced by surface modified single-walled carbon nanotubes.

    PubMed

    Fent, János; Bihari, Péter; Vippola, Minnamari; Sarlin, Essi; Lakatos, Susan

    2015-08-01

    Surface modification of single-walled carbon nanotubes (SWCNTs) such as carboxylation, amidation, hydroxylation and pegylation is used to reduce the nanotube toxicity and render them more suitable for biomedical applications than their pristine counterparts. Toxicity can be manifested in platelet activation as it has been shown for SWCNTs. However, the effect of various surface modifications on the platelet activating potential of SWCNTs has not been tested yet. In vitro platelet activation (CD62P) as well as the platelet-granulocyte complex formation (CD15/CD41 double positivity) in human whole blood were measured by flow cytometry in the presence of 0.1mg/ml of pristine or various surface modified SWCNTs. The effect of various SWCNTs was tested by whole blood impedance aggregometry, too. All tested SWCNTs but the hydroxylated ones activate platelets and promote platelet-granulocyte complex formation in vitro. Carboxylated, pegylated and pristine SWCNTs induce whole blood aggregation as well. Although pegylation is preferred from biomedical point of view, among the samples tested by us pegylated SWCNTs induced far the most prominent activation and a well detectable aggregation of platelets in whole blood. PMID:25956790

  10. BCG Vaccination Induces Robust CD4+ T Cell Responses to Mycobacterium tuberculosis Complex-Specific Lipopeptides in Guinea Pigs.

    PubMed

    Kaufmann, Eva; Spohr, Christina; Battenfeld, Sibylle; De Paepe, Diane; Holzhauser, Thomas; Balks, Elisabeth; Homolka, Susanne; Reiling, Norbert; Gilleron, Martine; Bastian, Max

    2016-03-15

    A new class of highly antigenic, MHC-II-restricted mycobacterial lipopeptides that are recognized by CD4-positive T lymphocytes of Mycobacterium tuberculosis-infected humans has recently been described. To investigate the relevance of this novel class of mycobacterial Ags in the context of experimental bacille Calmette-Guérin (BCG) vaccination, Ag-specific T cell responses to mycobacterial lipid and lipopeptide-enriched Ag preparations were analyzed in immunized guinea pigs. Lipid and lipopeptide preparations as well as complex Ag mixtures, such as tuberculin, mycobacterial lysates, and culture supernatants, all induced a similar level of T cell proliferation. The hypothesis that lipopeptide-specific T cells dominate the early BCG-induced T cell response was corroborated in restimulation assays by the observation that Ag-expanded T cells specifically responded to the lipopeptide preparation. A comparative analysis of the responses to Ag preparations from different mycobacterial species revealed that the antigenic lipopeptides are specific for strains of the M. tuberculosis complex. Their intriguing conservation in pathogenic tuberculous bacteria and the fact that these highly immunogenic Ags seem to be actively released during in vitro culture and intracellular infection prompt the urgent question about their role in the fine-tuned interplay between the pathogen and its mammalian host, in particular with regard to BCG vaccination strategies. PMID:26889044

  11. Cdc37-Hsp90 Complexes Are Responsive to Nucleotide-induced Conformational Changes and Binding of Further Cofactors*

    PubMed Central

    Gaiser, Andreas M.; Kretzschmar, Anja; Richter, Klaus

    2010-01-01

    Hsp90 is an ATP-dependent molecular chaperone, which facilitates the activation and stabilization of hundreds of client proteins in cooperation with a defined set of cofactors. Many client proteins are protein kinases, which are activated and stabilized by Hsp90 in cooperation with the kinase-specific co-chaperone Cdc37. Other Hsp90 co-chaperones, like the ATPase activator Aha1, also are implicated in kinase activation, and it is not yet clear how Cdc37 is integrated into Hsp90 co-chaperone complexes. Here, we studied the interaction between Cdc37, Hsp90, and other Hsp90 co-chaperones from the nematode Caenorhabditis elegans. Nematode Cdc37 binds with high affinity to Hsp90 and strongly inhibits the ATPase activity. In contrast to the human Hsp90 system, we observed binding of Cdc37 to open and closed Hsp90 conformations, potentially reflecting two different binding modes. Using a novel ultracentrifugation setup, which allows accurate analysis of multifactorial protein complexes, we show that cooperative and competitive interactions exist between other co-chaperones and Cdc37-Hsp90 complexes in the C. elegans system. We observed strong competitive interactions between Cdc37 and the co-chaperones p23 and Sti1, whereas the binding of the phosphatase Pph5 and the ATPase activator Aha1 to Cdc37-Hsp90 complexes is possible. The ternary Aha1-Cdc37-Hsp90 complex is disrupted by the nucleotide-induced closing reaction at the N terminus of Hsp90. This implies a carefully regulated exchange process of cofactors during the chaperoning of kinase clients by Hsp90. PMID:20880838

  12. Interleukin-2/Anti-Interleukin-2 Immune Complex Expands Regulatory T Cells and Reduces Angiotensin II-Induced Aortic Stiffening.

    PubMed

    Majeed, Beenish; Tawinwung, Supannikar; Eberson, Lance S; Secomb, Timothy W; Larmonier, Nicolas; Larson, Douglas F

    2014-01-01

    Adaptive immune function is implicated in the pathogenesis of vascular disease. Inhibition of T-lymphocyte function has been shown to reduce hypertension, target-organ damage, and vascular stiffness. To study the role of immune inhibitory cells, CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs), on vascular stiffness, we stimulated the proliferation of Treg lymphocytes in vivo using a novel cytokine immune complex of Interleukin-2 (IL-2) and anti-IL-2 monoclonal antibody clone JES6-1 (mAbCD25). Three-month-old male C57BL/6J mice were treated with IL-2/mAbCD25 concomitantly with continuous infusion of angiotensin type 1 receptor agonist, [Val(5)]angiotensin II. Our results indicate that the IL-2/mAbCD25 complex effectively induced Treg phenotype expansion by 5-fold in the spleens with minimal effects on total CD4(+) and CD8(+) T-lymphocyte numbers. The IL-2/mAbCD25 complex inhibited angiotensin II-mediated aortic collagen remodeling and the resulting stiffening, analyzed with in vivo pulse wave velocity and effective Young's modulus. Furthermore, the IL-2/mAbCD25 complex suppressed angiotensin II-mediated Th17 responses in the lymphoid organs and reduced gene expression of IL-17 as well as T cell and macrophage infiltrates in the aortic tissue. This study provides data that support the protective roles of Tregs in vascular stiffening and highlights the use of the IL-2/mAbCD25 complex as a new potential therapy in angiotensin II-related vascular diseases. PMID:25258681

  13. Carotenoid-induced non-photochemical quenching in the cyanobacterial chlorophyll synthase-HliC/D complex.

    PubMed

    Niedzwiedzki, Dariusz M; Tronina, Tomasz; Liu, Haijun; Staleva, Hristina; Komenda, Josef; Sobotka, Roman; Blankenship, Robert E; Polívka, Tomáš

    2016-09-01

    Chl synthase (ChlG) is an important enzyme of the Chl biosynthetic pathway catalyzing attachment of phytol/geranylgeraniol tail to the chlorophyllide molecule. Here we have investigated the Flag-tagged ChlG (f.ChlG) in a complex with two different high-light inducible proteins (Hlips) HliD and HliC. The f.ChlG-Hlips complex binds a Chl a and three different carotenoids, β-carotene, zeaxanthin and myxoxanthophyll. Application of ultrafast time-resolved absorption spectroscopy performed at room and cryogenic temperatures revealed excited-state dynamics of complex-bound pigments. After excitation of Chl a in the complex, excited Chl a is efficiently quenched by a nearby carotenoid molecule via energy transfer from the Chl a Qy state to the carotenoid S1 state. The kinetic analysis of the spectroscopic data revealed that quenching occurs with a time constant of ~2ps and its efficiency is temperature independent. Even though due to its long conjugation myxoxanthophyll appears to be energetically best suited for role of Chl a quencher, based on comparative analysis and spectroscopic data we propose that β-carotene bound to Hlips acts as the quencher rather than myxoxanthophyll and zeaxanthin, which are bound at the f.ChlG and Hlips interface. The S1 state lifetime of the quencher has been determined to be 13ps at room temperature and 21ps at 77K. These results demonstrate that Hlips act as a conserved functional module that prevents photodamage of protein complexes during photosystem assembly or Chl biosynthesis. PMID:27133505

  14. Glycolic Acid Silences Inflammasome Complex Genes, NLRC4 and ASC, by Inducing DNA Methylation in HaCaT Cells.

    PubMed

    Tang, Sheau-Chung; Yeh, Jih-I; Hung, Sung-Jen; Hsiao, Yu-Ping; Liu, Fu-Tong; Yang, Jen-Hung

    2016-03-01

    AHAs (α-hydroxy acids), including glycolic acid (GA), have been widely used in cosmetic products and superficial chemical peels. Inflammasome complex has been shown to play critical roles in inflammatory pathways in human keratinocytes. However, the anti-inflammatory mechanism of GA is still unknown. The aim of this study is to investigate the relationship between the expression of the inflammasome complex and epigenetic modification to elucidate the molecular mechanism of the anti-inflammatory effect of GA in HaCaT cells. We evaluated NLRP3, NLRC4, AIM2, and ASC inflammasome complex gene expression on real-time polymerase chain reaction (PCR). Methylation changes were detected in these genes following treatment with DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (5-Aza) with or without the addition of GA using methylation-specific PCR (MSP). GA inhibited the expressions of these inflammasome complex genes, and the decreases in the expressions of mRNA were reversed by 5-Aza treatment. Methylation was detected in NLRC4 and ASC on MSP, but not in NLRP3 or AIM2. GA decreased NLRC4 and ASC gene expression by increasing not only DNA methyltransferase 3B (DNMT-3B) protein level, but also total DNMT activity. Furthermore, silencing of DNMT-3B (shDNMT-3B) increased the expressions of NLRC4 and ASC. Our data demonstrated that GA treatment induces hypermethylation of promoters of NLRC4 and ASC genes, which may subsequently lead to the hindering of the assembly of the inflammasome complex in HaCaT cells. These results highlight the anti-inflammatory potential of GA-containing cosmetic agents in human skin cells and demonstrate for the first time the role of aberrant hypermethylation in this process. PMID:26784358

  15. Cellular responses induced by Cu(II) quinolinonato complexes in human tumor and hepatic cells

    PubMed Central

    2012-01-01

    Background Inspired by the unprecedented historical success of cisplatin, one of the most important research directions in bioinorganic and medicinal chemistry is dedicated to the development of new anticancer compounds with the potential to surpass it in antitumor activity, while having lower unwanted side-effects. Therefore, a series of copper(II) mixed-ligand complexes of the type [Cu(qui)(L)]Y · xH2O (1–6), where Hqui = 2-phenyl-3-hydroxy-4(1H)-quinolinone, Y = NO3 (1, 3, 5) or BF4 (2, 4, 6), and L = 1,10-phenanthroline (phen) (1, 2), 5-methyl-1,10-phenanthroline (mphen) (3, 4) and bathophenanthroline (bphen) (5, 6), was studied for their in vitro cytotoxicity against several human cancer cell lines (A549 lung carcinoma, HeLa cervix epitheloid carcinoma, G361 melanoma cells, A2780 ovarian carcinoma, A2780cis cisplatin-resistant ovarian carcinoma, LNCaP androgen-sensitive prostate adenocarcinoma and THP-1 monocytic leukemia). Results The tested complexes displayed a stronger cytotoxic effect against all the cancer cells as compared to cisplatin. The highest cytotoxicity was found for the complexes 4 (IC50 = 0.36 ± 0.05 μM and 0.56 ± 0.15 μM), 5 (IC50 = 0.66 ± 0.07 μM and 0.73 ± 0.08 μM) and 6 (IC50 = 0.57 ± 0.11 μM and 0.70 ± 0.20 μM) against A2780, and A2780cis respectively, as compared with the values of 12.0 ± 0.8 μM and 27.0 ± 4.6 μM determined for cisplatin. Moreover, the tested complexes were much less cytotoxic to primary human hepatocytes than to the cancer cells. The complexes 5 and 6 exhibited significantly high ability to modulate secretion of the pro-inflammatory cytokines TNF-α (2873 ± 238 pg/mL and 3284 ± 139 pg/mL for 5, and 6 respectively) and IL-1β (1177 ± 128 pg/mL and 1087 ± 101 pg/mL for 5, and 6 respectively) tested on the lipopolysaccharide (LPS)-stimulated THP-1 cells as compared with the values of 1173 ± 85

  16. pH-Regulated Reversible Transition Between Polyion Complexes (PIC) and Hydrogen-Bonding Complexes (HBC) with Tunable Aggregation-Induced Emission.

    PubMed

    Tian, Sidan; Liu, Guhuan; Wang, Xiaorui; Wu, Tao; Yang, Jinxian; Ye, Xiaodong; Zhang, Guoying; Hu, Jinming; Liu, Shiyong

    2016-02-17

    The mimicking of biological supramolecular interactions and their mutual transitions to fabricate intelligent artificial systems has been of increasing interest. Herein, we report the fabrication of supramolecular micellar nanoparticles consisting of quaternized poly(ethylene oxide)-b-poly(2-dimethylaminoethyl methacrylate) (PEO-b-PQDMA) and tetrakis(4-carboxylmethoxyphenyl)ethene (TPE-4COOH), which was capable of reversible transition between polyion complexes (PIC) and hydrogen bonding complexes (HBC) with tunable aggregation-induced emission (AIE) mediated by solution pH. At pH 8, TPE-4COOH chromophores can be directly dissolved in aqueous milieu without evident fluorescence emission. However, upon mixing with PEO-b-PQDMA, polyion complexes were formed by taking advantage of electrostatic interaction between carboxylate anions and quaternary ammonium cations and the most compact PIC micelles were achieved at the isoelectric point (i.e., [QDMA(+)]/[COO(-)] = 1), as confirmed by dynamic light scattering (DLS) measurement. Simultaneously, fluorescence spectroscopy revealed an evident emission turn-on and the maximum fluorescence intensity was observed near the isoelectric point due to the restriction of intramolecular rotation of TPE moieties within the PIC cores. The kinetic study supported a micelle fusion/fission mechanism on the formation of PIC micelles at varying charge ratios, exhibiting a quick time constant (τ1) relating to the formation of quasi-equilibrium micelles and a slow time constant (τ2) corresponding to the formation of final equilibrium micelles. Upon deceasing the pH of PIC micelles from 8 to 2 at the [QDMA(+)]/[COO(-)] molar ratio of 1, TPE-4COOH chromophores became gradually protonated and hydrophobic. The size of micellar nanoparticles underwent a remarkable decrease, whereas the fluorescence intensity exhibited a further increase by approximately 7.35-fold, presumably because of the formation of HBC micelles comprising cationic PQDMA

  17. Peroxidative permeabilization of liposomes induced by cytochrome c/cardiolipin complex.

    PubMed

    Firsov, Alexander M; Kotova, Elena A; Korepanova, Evgeniya A; Osipov, Anatoly N; Antonenko, Yuri N

    2015-03-01

    Interaction of cytochrome c with mitochondrial cardiolipin converting this electron transfer protein into peroxidase is accepted to play an essential role in apoptosis. Cytochrome c/cardiolipin peroxidase activity was found here to cause leakage of carboxyfluorescein, sulforhodamine B and 3-kDa (but not 10-kDa) fluorescent dextran from liposomes. A marked decrease in the amplitude of the autocorrelation function was detected with a fluorescence correlation spectroscopy setup upon incubation of dye-loaded cardiolipin-containing liposomes with cytochrome c and H2O2, thereby showing release of fluorescent markers from liposomes. The cytochrome c/H2O2-induced liposome leakage was suppressed upon increasing the ionic strength, in contrast to the leakage provoked by Fe/ascorbate, suggesting that the binding of cyt c to negatively-charged membranes was required for the permeabilization process. The cyt c/H2O2-induced liposome leakage was abolished by cyanide presumably competing with H2O2 for coordination with the central iron atom of the heme in cyt c. The cytochrome c/H2O2 permeabilization activity was substantially diminished by antioxidants (trolox, butylhydroxytoluene and quercetin) and was precluded if fully saturated tetramyristoyl-cardiolipin was substituted for bovine heart cardiolipin. These data favor the involvement of oxidized cardiolipin molecules in membrane permeabilization resulting from cytochrome c/cardiolipin peroxidase activity. In agreement with previous observations, high concentrations of cyt c induced liposome leakage in the absence of H2O2, however this process was not sensitive to antioxidants and cyanide suggesting direct membrane poration by the protein without the involvement of lipid peroxidation. PMID:25485477

  18. The c-Jun-induced transformation process involves complex regulation of tenascin-C expression.

    PubMed Central

    Mettouchi, A; Cabon, F; Montreau, N; Dejong, V; Vernier, P; Gherzi, R; Mercier, G; Binétruy, B

    1997-01-01

    In cooperation with an activated ras oncogene, the site-dependent AP-1 transcription factor c-Jun transforms primary rat embryo fibroblasts (REF). Although signal transduction pathways leading to activation of c-Jun proteins have been extensively studied, little is known about c-Jun cellular targets. We identified c-Jun-upregulated cDNA clones homologous to the tenascin-C gene by differential screening of a cDNA library from REF. This tightly regulated gene encodes a rare extracellular matrix protein involved in cell attachment and migration and in the control of cell growth. Transient overexpression of c-Jun induced tenascin-C expression in primary REF and in FR3T3, an established fibroblast cell line. Surprisingly, tenascin-C synthesis was repressed after stable transformation by c-Jun compared to that in the nontransformed parental cells. As assessed by using the tenascin-C (-220 to +79) promoter fragment cloned in a reporter construct, the c-Jun-induced transient activation is mediated by two binding sites: one GCN4/AP-1-like site, at position -146, and one NF-kappaB site, at position -210. Furthermore, as demonstrated by gel shift experiments and cotransfections of the reporter plasmid and expression vectors encoding the p65 subunit of NF-kappaB and c-Jun, the two transcription factors bind and synergistically transactivate the tenascin-C promoter. We previously described two other extracellular matrix proteins, SPARC and thrombospondin-1, as c-Jun targets. Thus, our results strongly suggest that the regulation of the extracellular matrix composition plays a central role in c-Jun-induced transformation. PMID:9154819

  19. Forskolin-inducible cAMP Pathway Negatively Regulates T-cell Proliferation by Uncoupling the Interleukin-2 Receptor Complex*

    PubMed Central

    Rodriguez, Georgialina; Ross, Jeremy A.; Nagy, Zsuzsanna S.; Kirken, Robert A.

    2013-01-01

    Cytokine-mediated regulation of T-cell activity involves a complex interplay between key signal transduction pathways. Determining how these signaling pathways cross-talk is essential to understanding T-cell function and dysfunction. In this work, we provide evidence that cross-talk exists between at least two signaling pathways: the Jak3/Stat5 and cAMP-mediated cascades. The adenylate cyclase activator forskolin (Fsk) significantly increased intracellular cAMP levels and reduced proliferation of the human T-cells via inhibition of cell cycle regulatory genes but did not induce apoptosis. To determine this inhibitory mechanism, effects of Fsk on IL-2 signaling was investigated. Fsk treatment of MT-2 and Kit 225 T-cells inhibited IL-2-induced Stat5a/b tyrosine and serine phosphorylation, nuclear translocation, and DNA binding activity. Fsk treatment also uncoupled IL-2 induced association of the IL-2Rβ and γc chain, consequently blocking Jak3 activation. Interestingly, phosphoamino acid analysis revealed that Fsk-treated cells resulted in elevated serine phosphorylation of Jak3 but not Stat5, suggesting that Fsk can negatively regulate Jak3 activity possibly mediated through PKA. Indeed, in vitro kinase assays and small molecule inhibition studies indicated that PKA can directly serine phosphorylate and functionally inactivate Jak3. Taken together, these findings suggest that Fsk activation of adenylate cyclase and PKA can negatively regulate IL-2 signaling at multiple levels that include IL-2R complex formation and Jak3/Stat5 activation. PMID:23341462

  20. What musicians do to induce the sensation of groove in simple and complex melodies, and how listeners perceive it.

    PubMed

    Madison, Guy; Sioros, George

    2014-01-01

    Groove is the experience of wanting to move when hearing music, such as snapping fingers or tapping feet. This is a central aspect of much music, in particular of music intended for dancing. While previous research has found considerable consistency in ratings of groove across individuals, it remains unclear how groove is induced, that is, what are the physical properties of the acoustic signal that differ between more and less groove-inducing versions. Here, we examined this issue with a performance experiment, in which four musicians performed six simple and six complex melodies in two conditions with the intention of minimizing and maximizing groove. Analyses of rhythmical and temporal properties from the performances demonstrated some general effects. For example, more groove was associated with more notes on faster metrical levels and syncopation, and less groove was associated with deadpan timing and destruction of the regular pulse. We did not observe that deviations from the metrical grid [i.e., micro-timing (MT)] were a predictor of groove. A listener experiment confirmed that the musicians' manipulations had the intended effects on the experience of groove. A Brunswikian lens model was applied, which estimates the performer-perceiver communication across the two experiments. It showed that the communication achievement for simple melodies was 0.62, and that the matching of performers' and listeners' use of nine rhythmical cues was 0.83. For complex melodies with an already high level of groove, the corresponding values were 0.39 and 0.34, showing that it was much more difficult to "take out" groove from musical structures designed to induce groove. PMID:25191286

  1. Circulating Complexes of the Vitamin D Binding Protein with G-Actin Induce Lung Inflammation by Targeting Endothelial Cells

    PubMed Central

    Ge, Lingyin; Trujillo, Glenda; Miller, Edmund J.; Kew, Richard R.

    2013-01-01

    This study investigated the actin scavenger function of the vitamin D binding protein (DBP) in vivo using DBP null (−/−) mice. Intravenous injection of G-actin into wild-type (DBP+/+) and DBP−/− mice showed that contrary to expectations, DBP+/+ mice developed more severe acute lung inflammation. Inflammation was restricted to the lung and pathological changes were clearly evident at 1.5 and 4 hours post-injection but were largely resolved by 24 hours. Histology of DBP+/+ lungs revealed noticeably more vascular leakage, hemorrhage and thickening of the alveolar wall. Flow cytometry analysis of whole lung homogenates showed significantly increased neutrophil infiltration into DBP+/+ mouse lungs at 1.5 and 4 hours. Increased amounts of protein and leukocytes were also noted in bronchoalveolar lavage fluid from DBP+/+ mice 4 hours after actin injection. In vitro, purified DBP-actin complexes did not activate complement or neutrophils but induced injury and death of cultured human lung microvascular endothelial cells (HLMVEC) and human umbilical vein endothelial cells (HUVEC). Cells treated with DBP-actin showed a significant reduction in viability at 4 hours, this effect was reversible if cells were cultured in fresh media for another 24 hours. However, a 24-hour treatment with DBP-actin complexes showed a significant increase in cell death (95% for HLMVEC, 45% for HUVEC). The mechanism of endothelial cell death was via both caspase-3 dependent (HUVEC) and independent (HLMVEC) pathways. These results demonstrate that elevated levels and/or prolonged exposure to DBP-actin complexes may induce endothelial cell injury and death, particularly in the lung microvasculature. PMID:24268110

  2. BCNU-INDUCED GR2 DEFECT MEDIATES S-GLUTATHIONYLATION OF COMPLEX I AND RESPIRATORY UNCOUPLING IN MYOCARDIUM†

    PubMed Central

    Kang, Patrick T.; Chen, Chwen-Lih; Zen, Pei; Guarini, Giacinta; Chen, Yeong-Renn

    2014-01-01

    A deficiency of mitochondrial glutathione reductase (or GR2) is capable of adversely affecting the reduction of GSSG and increasing mitochondrial oxidative stress. BCNU [1, 3-bis (2-chloroethyl)-1-nitrosourea] is an anticancer agent and known inhibitor of cytosolic GR ex vivo and in vivo. Here we tested the hypothesis that a BCNU-induced GR2 defect contributes to mitochondrial dysfunction and subsequent impairment of heart function. Intraperitoneal administration of BCNU (40 mg/kg) specifically inhibited GR2 activity by 79.8±2.7% in the mitochondria of rat heart. However, BCNU treatment modestly enhanced the activities of mitochondrial Complex I and other ETC components. The cardiac function of BCNU-treated rats was analyzed by echocardiography, revealing a systolic dysfunction associated with decreased ejection fraction, decreased cardiac output, and an increase in left ventricular internal dimension and left ventricular volume in systole. The respiratory control index of isolated mitochondria from the myocardium was moderately decreased after BCNU treatment, whereas NADH-linked uncoupling of oxygen consumption was significantly enhanced. Extracellular flux analysis to measure the fatty acid oxidation of myocytes indicated a 20% enhancement after BCNU treatment. When the mitochondria were immunoblotted with antibodies against GSH and UCP3, both protein S-glutathionylation of Complex I and expression of UCP3 were significantly up-regulated. Overexpression of SOD2 in the myocardium significantly reversed BCNU-induced GR2 inhibition and mitochondrial impairment. In conclusion, BCNU-mediated cardiotoxicity is characterized by the GR2 deficiency that negatively regulates heart function by impairing mitochondrial integrity, increasing oxidative stress with Complex I S-glutathionylation, and enhancing uncoupling of mitochondrial respiration. PMID:24704251

  3. Inducible STAT3 NH2 Terminal Mono-ubiquitination Promotes BRD4 Complex Formation to Regulate Apoptosis

    PubMed Central

    Ray, Sutapa; Zhao, Yingxin; Jamaluddin, Mohammad; Edeh, Chukwudi B.; Lee, Chang; Brasier, Allan R.

    2014-01-01

    Signal Transducers and Activator of Transcription-3 (STAT3) are latent transcription factors that are regulated by post-translational modifications (PTMs) in response to cellular activation by the IL-6 superfamily of cytokines to regulate cell cycle progression and/or apoptosis. Here we observe that STAT3 is inducibly mono-ubiquitinated and investigate its consequences. Using domain mapping and highly specific selected reaction monitoring- mass spectrometric assays, we identify lysine (K) 97 in its NH2-terminal domain as the major mono-ubiquitin conjugation site. We constructed a mono-ubiquitinated mimic consisting of a deubiquitinase-resistant monomeric ubiquitin fused to the NH2 terminus of STAT3 (ubiquitinated-STAT3 FP). In complex assays of ectopically expressed ubi-STAT3-FP, we observed enhanced complex formation with bromodomain -containing protein 4 (BRD4), a component of the activated positive transcriptional elongation factor (P-TEFb) complex. Chromatin immunoprecipitation experiments in STAT3+/− and STAT3−/− MEFs showed BRD4 recruitment to STAT3-dependent suppressor of cytokine signaling-3 gene (SOCS3). The effect of a selective small molecule inhibitor of BRD4, JQ1, to inhibit SOCS3 expression demonstrated the functional role of BRD4 for STAT3-dependent transcription. Additionally, ectopic ubiquitinated-STAT3 FP expression upregulated BCL2, BCL2L1, APEX1, SOD2, CCND1 and MYC expression indicating the role of ubiquitinated STAT3 in anti-apoptosis and cellular proliferation. Finally we observed that ubiquitinated-STAT3 FP suppressed TNFα-induced apoptotic cell death, indicating the functional importance of mono-ubiquitinated STAT3 in antiapoptotic gene expression. We conclude that STAT3 mono-ubiquitination is a key trigger in BRD4-dependent antiapoptotic and pro-proliferative gene expression programs. Thus, inhibiting the STAT3 mono-ubiquitination - BRD4 pathway may be a novel therapeutic target for the treatment of STAT3-dependent proliferative

  4. Inducible STAT3 NH2 terminal mono-ubiquitination promotes BRD4 complex formation to regulate apoptosis.

    PubMed

    Ray, Sutapa; Zhao, Yingxin; Jamaluddin, Mohammad; Edeh, Chukwudi B; Lee, Chang; Brasier, Allan R

    2014-07-01

    Signal Transducers and Activator of Transcription-3 (STAT3) are latent transcription factors that are regulated by post-translational modifications (PTMs) in response to cellular activation by the IL-6 superfamily of cytokines to regulate cell cycle progression and/or apoptosis. Here we observe that STAT3 is inducibly mono-ubiquitinated and investigate its consequences. Using domain mapping and highly specific selected reaction monitoring-mass spectrometric assays, we identify lysine (K) 97 in its NH2-terminal domain as the major mono-ubiquitin conjugation site. We constructed a mono-ubiquitinated mimic consisting of a deubiquitinase-resistant monomeric ubiquitin fused to the NH2 terminus of STAT3 (ubiquitinated-STAT3 FP). In complex assays of ectopically expressed ubi-STAT3-FP, we observed enhanced complex formation with bromodomain-containing protein 4 (BRD4), a component of the activated positive transcriptional elongation factor (P-TEFb) complex. Chromatin immunoprecipitation experiments in STAT3(+/-) and STAT3(-/-) MEFs showed BRD4 recruitment to STAT3-dependent suppressor of cytokine signaling-3 gene (SOCS3). The effect of a selective small molecule inhibitor of BRD4, JQ1, to inhibit SOCS3 expression demonstrated the functional role of BRD4 for STAT3-dependent transcription. Additionally, ectopic ubiquitinated-STAT3 FP expression upregulated BCL2, BCL2L1, APEX1, SOD2, CCND1 and MYC expression indicating the role of ubiquitinated STAT3 in anti-apoptosis and cellular proliferation. Finally we observed that ubiquitinated-STAT3 FP suppressed TNFα-induced apoptotic cell death, indicating the functional importance of mono-ubiquitinated STAT3 in antiapoptotic gene expression. We conclude that STAT3 mono-ubiquitination is a key trigger in BRD4-dependent antiapoptotic and pro-proliferative gene expression programs. Thus, inhibiting the STAT3 mono-ubiquitination-BRD4 pathway may be a novel therapeutic target for the treatment of STAT3-dependent proliferative diseases

  5. Molecular analysis of mutations induced at the hisD3052 allele of Salmonella by single chemicals and complex mixtures.

    PubMed Central

    DeMarini, D M; Bell, D A; Levine, J G; Shelton, M L; Abu-Shakra, A

    1993-01-01

    More single chemicals and complex environmental mixtures have been evaluated for mutagenicity at the hisD3052 allele of Salmonella, primarily in strain TA98, than in any other mutation assay. The development of colony probe hybridization procedures and the application of the polymerase chain reaction and direct DNA sequencing has permitted rapid molecular access to this allele. We discuss these techniques and the resulting mutation spectra that have been induced by a variety of environmental mutagens and complex mixtures. A common GC or CG deletion within a hot-spot region of the sequence dominates most of the spectra. In addition to this two-base deletion, we have recovered about 200 other types of mutations within the 72-base target for reversion of the hisD3052 allele. These include a variety of deletions (as large as 35 bases), duplications (as large as 46 bases), and complex mutations involving base substitutions. The quasipalindromic nature of the target sequence and its potential to form DNA secondary structures and slippage mismatches appear to be an important basis for the mutability of this allele. PMID:8143618

  6. U1 small nuclear ribonucleoprotein immune complexes induce type I interferon in plasmacytoid dendritic cells through TLR7.

    PubMed

    Savarese, Emina; Chae, Ohk-wha; Trowitzsch, Simon; Weber, Gert; Kastner, Berthold; Akira, Shizuo; Wagner, Hermann; Schmid, Roland M; Bauer, Stefan; Krug, Anne

    2006-04-15

    Plasmacytoid dendritic cells (PDCs), which produce IFN-alpha in response to autoimmune complexes containing nuclear antigens, are thought to be critically involved in the pathogenesis of systemic lupus erythematosus (SLE). One of the immunostimulatory components of SLE immune complexes (SLE-ICs) is self DNA, which is recognized through Tlr9 in PDCs and B cells. Small nuclear ribonucleoproteins (snRNPs) are another major component of SLE-ICs in 30% to 40% of patients. In this study, we show that murine PDCs are activated by purified U1snRNP/anti-Sm ICs to produce IFN-alpha and proinflammatory cytokines and to up-regulate costimulatory molecules. The induction of IFN-alpha and IL-6 by U1snRNPs in murine bone marrow-derived PDCs required the presence of intact U1RNA and was largely dependent on Tlr7 but independent of Tlr3. Intracellularly delivered isolated U1snRNA and oligoribonucleotides derived from the stem loop regions and the Sm-binding site of U1snRNA efficiently induced IFN-alpha and IL-6 in Flt3L-cultured DCs in a Tlr7-dependent manner. The U1snRNA component of U1snRNP immune complexes, found in patients with SLE, acts as an endogenous "self" ligand for Tlr7 and triggers IFN-alpha and IL-6 production in PDCs. PMID:16368889

  7. Involvement of Polycomb Repressive Complex 2 in Maturation of Induced Pluripotent Stem Cells during Reprogramming of Mouse and Human Fibroblasts.

    PubMed

    Khazaie, Niusha; Massumi, Mohammad; Wee, Ping; Salimi, Mahdieh; Mohammadnia, Abdulshakour; Yaqubi, Moein

    2016-01-01

    Induced pluripotent stem cells (iPSCs) provide a reliable source for the study of regenerative medicine, drug discovery, and developmental biology. Despite extensive studies on the reprogramming of mouse and human fibroblasts into iPSCs, the efficiency of reprogramming is still low. Here, we used a bioinformatics and systems biology approach to study the two gene regulatory waves governing the reprogramming of mouse and human fibroblasts into iPSCs. Our results revealed that the maturation phase of reprogramming was regulated by a more complex regulatory network of transcription factors compared to the initiation phase. Interestingly, in addition to pluripotency factors, the polycomb repressive complex 2 (PRC2) members Ezh2, Eed, Jarid2, Mtf2, and Suz12 are crucially recruited during the maturation phase of reprogramming. Moreover, we found that during the maturation phase of reprogramming, pluripotency factors, via the expression and induction of PRC2 complex members, could silence the lineage-specific gene expression program and maintain a ground state of pluripotency in human and mouse naïve iPSCs. The findings obtained here provide us a better understanding of the gene regulatory network (GRN) that governs reprogramming, and the maintenance of the naïve state of iPSCs. PMID:26938987

  8. Involvement of Polycomb Repressive Complex 2 in Maturation of Induced Pluripotent Stem Cells during Reprogramming of Mouse and Human Fibroblasts

    PubMed Central

    Khazaie, Niusha; Massumi, Mohammad; Wee, Ping; Salimi, Mahdieh; Mohammadnia, Abdulshakour; Yaqubi, Moein

    2016-01-01

    Induced pluripotent stem cells (iPSCs) provide a reliable source for the study of regenerative medicine, drug discovery, and developmental biology. Despite extensive studies on the reprogramming of mouse and human fibroblasts into iPSCs, the efficiency of reprogramming is still low. Here, we used a bioinformatics and systems biology approach to study the two gene regulatory waves governing the reprogramming of mouse and human fibroblasts into iPSCs. Our results revealed that the maturation phase of reprogramming was regulated by a more complex regulatory network of transcription factors compared to the initiation phase. Interestingly, in addition to pluripotency factors, the polycomb repressive complex 2 (PRC2) members Ezh2, Eed, Jarid2, Mtf2, and Suz12 are crucially recruited during the maturation phase of reprogramming. Moreover, we found that during the maturation phase of reprogramming, pluripotency factors, via the expression and induction of PRC2 complex members, could silence the lineage-specific gene expression program and maintain a ground state of pluripotency in human and mouse naïve iPSCs. The findings obtained here provide us a better understanding of the gene regulatory network (GRN) that governs reprogramming, and the maintenance of the naïve state of iPSCs. PMID:26938987

  9. Effect of drug-binding-induced deformation on the vibrational spectrum of a DNA.daunomycin complex

    NASA Astrophysics Data System (ADS)

    Chen, Y. Z.; Szabó, A.; Schroeter, D. F.; Powell, J. W.; Lee, S. A.; Prohofsky, E. W.

    1997-06-01

    Vibrational frequencies of a DNA.daunomycin complex and those of a free DNA helix and an isolated daunomycin are calculated and compared with the infrared spectrum of similar systems at frequencies above 600 cm-1. Our study indicates that the binding induces a considerable change in the vibrational spectrum of both DNA and the binding drug. The frequency shifts appear to be closely related to the conformational deformation in the complex caused by drug binding. Significant frequency shift is found in the normal modes in the DNA.drug complex that are primarily vibrations localized to the sugar-phosphate backbone of the binding site. Sizable frequency change is also found in the modes associated with base atoms involved in the drug binding and in the modes in regions of the binding daunomycin that are deformed by the binding. In contrast the frequency of the modes in the region with no significant deformation is relatively unchanged. The modification of the DNA dynamical force field by the nonbonded interactions between DNA and the drug is found to have little effect on the modes in DNA above 600 cm-1. The modification to the daunomycin dynamical force field appears to be sizable since the frequency of several daunomycin modes is changed by several cm-1. The close relationship between structure and spectrum revealed in this work is of potential application in the identification of sites and types of deformation of a biomolecule from Raman and infrared spectra.

  10. The BRPF2/BRD1-MOZ complex is involved in retinoic acid-induced differentiation of embryonic stem cells.

    PubMed

    Cho, Hye In; Kim, Min Seong; Jang, Yeun Kyu

    2016-08-01

    The scaffold protein BRPF2 (also called BRD1), a key component of histone acetyltransferase complexes, plays an important role in embryonic development, but its function in the differentiation of embryonic stem cells (ESCs) remains unknown. In the present study, we investigated whether BRPF2 is involved in mouse ESC differentiation. BRPF2 depletion resulted in abnormal formation of embryoid bodies, downregulation of differentiation-associated genes, and persistent maintenance of alkaline phosphatase activity even after retinoic acid-induced differentiation, indicating impaired differentiation of BRPF2-depleted ESCs. We also found reduced global acetylation of histone H3 lysine 14 (H3K14) in BRPF2-depleted ESCs, irrespective of differentiation status. Further, co-immunoprecipitation analysis revealed a physical association between BRPF2 and the histone acetyltransferase MOZ in differentiated ESCs, suggesting the role of BRPF2-MOZ complexes in ESC differentiation. Together, these results suggest that BRPF2-MOZ complexes play an important role in the differentiation of ESCs via H3K14 acetylation. PMID:27256846

  11. Optimized Design and Use of Induced Complex Fractures in Horizontal Wellbores of Tight Gas Reservoirs

    NASA Astrophysics Data System (ADS)

    Zeng, F. H.; Guo, J. C.

    2016-04-01

    Multistage hydraulic fracturing is being increasing use in the establishment of horizontal wells in tight gas reservoirs. Connecting hydraulic fractures to natural and stress-induced fractures can further improve well productivity. This paper investigates the fracture treatment design issues involved in the establishment of horizontal wellbores, including the effects of geologic heterogeneity, perforation parameters, fracturing patterns, and construction parameters on stress anisotropy during hydraulic fracturing and on natural fractures during hydraulic fracture propagation. The extent of stress reversal and reorientation was calculated for fractures induced by the creation of one or more propped fractures. The effects of stress on alternate and sequential fracturing horizontal well and on the reservoir's mechanical properties, including the spatial extent of stress reorientation caused by the opening of fractures, were assessed and quantified. Alternate sequencing of transverse fractures was found to be an effective means of enhancing natural fracture stimulation by allowing fractures to undergo less stress contrast during propagation. The goal of this paper was to present a new approach to design that optimizes fracturing in a horizontal wellbore from the perspectives of both rock mechanics and fluid production. The new design is a modified version of alternate fracturing, where the fracture-initiation sequence was controlled by perforation parameters with a staggered pattern within a horizontal wellbore. Results demonstrated that the modified alternate fracturing performed better than original sequence fracturing and that this was because it increased the contact area and promoted more gas production in completed wells.

  12. A novel manganese complex selectively induces malignant glioma cell death by targeting mitochondria

    PubMed Central

    Geng, Ji; Li, Jing; Huang, Tao; Zhao, Kaidi; Chen, Qiuyun; Guo, Wenjie; Gao, Jing

    2016-01-01

    Despite advances in treatment, malignant glioma commonly exhibits recurrence, subsequently leading to a poor prognosis. As manganese (Mn) compounds can be transported by the transferrin-transferrin receptor system, the present study synthesized and examined the potential use of Adpa-Mn as a novel antitumor agent. Adpa-Mn time and dose-dependently inhibited U251 and C6 cell proliferation; however, it had little effect on normal astrocytes. Apoptosis was significantly elevated following treatment with Adpa-Mn, as detected by chromatin condensation, Annexin V/propidium iodide staining, cytochrome c release from mitochondria to the cytoplasm, and the activation of caspases-9, -7 and -3 and poly (ADP-ribose) polymerase. In addition, Adpa-Mn enhanced fluorescence intensity of monodansylcadaverine and elevated the expression levels of the autophagy-related protein microtubule-associated protein 1 light chain 3. Pretreatment with the autophagy inhibitors 3-methyladenine and chloroquine enhanced Adpa-Mn-induced cell inhibition, thus indicating that autophagy has an essential role in this process. Furthermore, evidence of mitochondrial dysfunction was detected in the Adpa-Mn-treated group, including disrupted membrane potential, elevated levels of reactive oxygen species (ROS) and depleted adenosine triphosphate. Conversely, treatment with the mitochondrial permeability transition inhibitor cyclosporin A reversed Adpa-Mn-induced ROS production, mitochondrial damage and cell apoptosis, thus suggesting that Adpa-Mn may target the mitochondria. Taken together, these data suggested that Adpa-Mn may be considered for use as a novel anti-glioma therapeutic option. PMID:27432745

  13. Operant and nonoperant vocal responding in the mynah: Complex schedule control and deprivation-induced responding

    PubMed Central

    Hake, D. F.; Mabry, J.

    1979-01-01

    Several recent studies have been concerned with operant responses that are also affected by nonoperant factors, (e.g., biological constraints, innate behavior patterns, respondent processes). The major reason for studying mynah vocal responding concerned the special relation of avian vocalizations to nonoperant emotional and reflexive systems. The research strategy was to evaluate operant and nonoperant control by comparing the schedule control obtained with the vocal response to that characteristic of the motor responses of other animals. We selected single, multiple, and chain schedules that ordinarily produce disparate response rates at predictable times. In multiple schedules with one component where vocal responding (“Awk”) was reinforced with food (fixed-ratio or fixed-interval schedule) and one where the absence of vocal responding was reinforced (differential reinforcement of other behavior), response rates never exceeded 15 responses per minute, but clear schedule differences developed in response rate and pause time. Nonoperant vocal responding was evident when responding endured across 50 extinction sessions at 25% to 40% of the rate during reinforcement. The “enduring extinction responding” was largely deprivation induced, because the operant-level of naive mynahs under food deprivation was comparable in magnitude, but without deprivation the operant level was much lower. Food deprivation can induce vocal responding, but the relatively precise schedule control indicated that operant contingencies predominate when they are introduced. PMID:16812153

  14. Human Immunodeficiency virus (HIV-1) Vpr induced downregulation of NHE1 induces alteration in intracellular pH and loss of ERM complex in target cells

    PubMed Central

    Janket, Michelle L.; DeRicco, Jeremy S.; Borowski, LuAnn; Ayyavoo, Velpandi

    2007-01-01

    Human Immunodeficiency Virus type 1 (HIV-1) Vpr is known to dysregulate host cellular functions through its interaction with cellular proteins. Using a protein array we assessed Vpr-mediated differential regulation of host cellular proteins expression. Results demonstrated that Vpr differentially regulated host factors that are involved in functions such as cell proliferation, differentiation and apoptosis. One of the most highly downregulated proteins attained was the sodium hydrogen exchanger, isoform 1 (NHE1), which showed a significant (60%) decrease in HIV-1 vpr(+) virus infected cells as compared to HIV-1 vpr(−) virus infected control. NHE1 downregulation further led to acidification of cells and was directly correlated with loss of ezrin, radixin and moesin (ERM) protein complex and decreased AKT phosphorylation. Vpr-mediated NHE1 dyregulation is in part through GR pathway as GR antagonist, mifepristone reversed Vpr-induced NHE1 downregulation. PMID:17349711

  15. Field induced modification of defect complexes in magnesium-doped lithium niobate

    SciTech Connect

    Meyer, Nadège; Granzow, Torsten; Nataf, Guillaume F.

    2014-12-28

    Dielectric constant, thermally stimulated depolarization currents (TSDC), and conductivity of undoped and 5% Mg-doped LiNbO{sub 3} single crystals between −100 °C and 200 °C have been investigated. A Debye-like dielectric relaxation with an activation energy of 135 meV is observed in the Mg-doped material, but not in undoped crystals. On heating this relaxation disappears near 140 °C and does not reappear after cooling. Anomalies observed in TSDC around this temperature are attributed to the motion of lithium vacancies, in agreement with conductivity measurements. It is proposed that in thermal equilibrium the electrons from the Mg{sub Li}{sup •} donors are trapped in (4Mg{sub Li}{sup •}+4V{sub Li}{sup ′}) defect complexes. High-temperature poling breaks these defect complexes. The transition of the liberated electrons between the Mg{sub Li}{sup •} donor centers and the Nb{sub Nb} forming the conduction band gives rise to the observed dielectric relaxation.

  16. Evolution of phase and morphology of titanium dioxide induced from peroxo titanate complex aqueous solution.

    PubMed

    Chang, Jeong Ah; Vithal, Muga; Baek, In Chan; Seok, Sang Il

    2010-01-01

    We demonstrate the growth of anatase TiO2 in nanospheres and rutile TiO2 in nanorods, by the hydrolysis of titanium tetraisopropoxide (TTIP) in the presence of hydrogen peroxide at 100 degrees C using sol-gel method. X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), scanning electron microscopy (SEM), and surface area measurement techniques are used to characterize the phase and shape developments of TiO2 obtained from peroxo titanate complex in an aqueous solution at 100 degrees C. Peroxo titanate complexes were prepared by a reaction of titanium hydroxide, formed by hydrolysis of titanium tetraisopropoxide (TTIP), and different amounts of hydrogen peroxide (H2O2). TEM and XRD investigations reveal that the size of spheres (anatase) and rods (rutile) are about 8 nm (diameter) and about 13 x 29 nm approximately 20 x 75 nm (width x length) respectively. The influence of molar ratio of H2O2/TTIP on the phase and morphology of TiO2 is presented. A mixture of anatase spheres and short rutile rods are formed at low H2O2/TTIP ratio while predominantly rutile a quit long rods are formed at higher H2O2/TTIP ratio. PMID:20352827

  17. The Responsive Amygdala: Treatment-induced Alterations in Functional Connectivity in Pediatric Complex Regional Pain Syndrome

    PubMed Central

    Simons, LE; Pielech, M; Erpelding, N; Linnman, C; Moulton, E; Sava, S; Lebel, A; Serrano, P; Sethna, N; Berde, C; Becerra, L; Borsook, D

    2014-01-01

    The amygdala is a key brain region with efferent and afferent neural connections that involve complex behaviors such as pain, reward, fear and anxiety. This study evaluated resting state functional connectivity of the amygdala with cortical and subcortical regions in a group of chronic pain patients (pediatric complex regional pain syndrome) with age-gender matched controls before and after intensive physical-biobehavioral pain treatment. Our main findings include (1) enhanced functional connectivity from the amygdala to multiple cortical, subcortical, and cerebellar regions in patients compared to controls, with differences predominantly in the left amygdala in the pre-treated condition (disease state); (2) dampened hyperconnectivity from the left amygdala to the motor cortex, parietal lobe, and cingulate cortex after intensive pain rehabilitation treatment within patients with nominal differences observed among healthy controls from Time 1 to Time 2 (treatment effects); (3) functional connectivity to several regions key to fear circuitry (prefrontal cortex, bilateral middle temporal lobe, bilateral cingulate, hippocampus) correlated with higher pain-related fear scores and (4) decreases in pain-related fear associated with decreased connectivity between the amygdala and the motor and somatosensory cortex, cingulate, and frontal areas. Our data suggest that there are rapid changes in amygdala connectivity following an aggressive treatment program in children with chronic pain and intrinsic amygdala functional connectivity activity serving as a potential indicator of treatment response. PMID:24861582

  18. Cerebral blood flow during paroxysmal EEG activation induced by sleep in patients with complex partial seizures

    SciTech Connect

    Gozukirmizi, E.; Meyer, J.S.; Okabe, T.; Amano, T.; Mortel, K.; Karacan, I.

    1982-01-01

    Cerebral blood flow (CBF) measurements were combined with sleep polysomnography in nine patients with complex partial seizures. Two methods were used: the 133Xe method for measuring regional (rCBF) and the stable xenon CT method for local (LCBF). Compared to nonepileptic subjects, who show diffuse CBF decreases during stages I-II, non-REM sleep onset, patients with complex partial seizures show statistically significant increases in CBF which are maximal in regions where the EEG focus is localized and are predominantly seen in one temporal region but are also propagated to other cerebral areas. Both CBF methods gave comparable results, but greater statistical significance was achieved by stable xenon CT methodology. CBF increases are more diffuse than predicted by EEG paroxysmal activity recorded from scalp electrodes. An advantage of the 133Xe inhalation method was achievement of reliable data despite movement of the head. This was attributed to the use of a helmet which maintained the probes approximated to the scalp. Disadvantages were poor resolution (7 cm3) and two-dimensional information. The advantage of stable xenon CT method is excellent resolution (80 mm3) in three dimensions, but a disadvantage is that movement of the head in patients with seizure disorders may limit satisfactory measurements.

  19. Redox-induced activation of the proton pump in the respiratory complex I

    PubMed Central

    Sharma, Vivek; Belevich, Galina; Gamiz-Hernandez, Ana P.; Róg, Tomasz; Vattulainen, Ilpo; Verkhovskaya, Marina L.; Wikström, Mårten; Hummer, Gerhard; Kaila, Ville R. I.

    2015-01-01

    Complex I functions as a redox-linked proton pump in the respiratory chains of mitochondria and bacteria, driven by the reduction of quinone (Q) by NADH. Remarkably, the distance between the Q reduction site and the most distant proton channels extends nearly 200 Å. To elucidate the molecular origin of this long-range coupling, we apply a combination of large-scale molecular simulations and a site-directed mutagenesis experiment of a key residue. In hybrid quantum mechanics/molecular mechanics simulations, we observe that reduction of Q is coupled to its local protonation by the His-38/Asp-139 ion pair and Tyr-87 of subunit Nqo4. Atomistic classical molecular dynamics simulations further suggest that formation of quinol (QH2) triggers rapid dissociation of the anionic Asp-139 toward the membrane domain that couples to conformational changes in a network of conserved charged residues. Site-directed mutagenesis data confirm the importance of Asp-139; upon mutation to asparagine the Q reductase activity is inhibited by 75%. The current results, together with earlier biochemical data, suggest that the proton pumping in complex I is activated by a unique combination of electrostatic and conformational transitions. PMID:26330610

  20. Cerebral blood flow during paroxysmal EEG activation induced by sleep in patients with complex partial seizures.

    PubMed

    Gozukirmizi, E; Meyer, J S; Okabe, T; Amano, T; Mortel, K; Karacan, I

    1982-01-01

    Cerebral blood flow (CBF) measurements were combined with sleep polysomnography in nine patients with complex partial seizures. Two methods were used: the 133Xe method for measuring regional (rCBF) and the stable xenon CT method for local (LCBF). Compared to nonepileptic subjects, who show diffuse CBF decreases during stages I-II, non-REM sleep onset, patients with complex partial seizures show statistically significant increases in CBF which are maximal in regions where the EEG focus is localized and are predominantly seen in one temporal region but are also propagated to other cerebral areas. Both CBF methods gave comparable results, but greater statistical significance was achieved by stable xenon CT methodology. CBF increases are more diffuse than predicted by EEG paroxysmal activity recorded from scalp electrodes. An advantage of the 133Xe inhalation method was achievement of reliable data despite movement of the head. This was attributed to the use of a helmet which maintained the probes approximated to the scalp. Disadvantages were poor resolution (7 cm3) and two-dimensional information. The advantage of stable xenon CT method is excellent resolution (80 mm3) in three dimensions, but a disadvantage is that movement of the head in patients with seizure disorders may limit satisfactory measurements. PMID:7163722

  1. The responsive amygdala: treatment-induced alterations in functional connectivity in pediatric complex regional pain syndrome.

    PubMed

    Simons, L E; Pielech, M; Erpelding, N; Linnman, C; Moulton, E; Sava, S; Lebel, A; Serrano, P; Sethna, N; Berde, C; Becerra, L; Borsook, D

    2014-09-01

    The amygdala is a key brain region with efferent and afferent neural connections that involve complex behaviors such as pain, reward, fear, and anxiety. This study evaluated resting state functional connectivity of the amygdala with cortical and subcortical regions in a group of chronic pain patients (pediatric complex regional pain syndrome) with age-sex matched control subjects before and after intensive physical-biobehavioral pain treatment. Our main findings include (1) enhanced functional connectivity from the amygdala to multiple cortical, subcortical, and cerebellar regions in patients compared with control subjects, with differences predominantly in the left amygdala in the pretreated condition (disease state); (2) dampened hyperconnectivity from the left amygdala to the motor cortex, parietal lobe, and cingulate cortex after intensive pain rehabilitation treatment within patients with nominal differences observed among healthy control subjects from time 1 to time 2 (treatment effects); (3) functional connectivity to several regions key to fear circuitry (prefrontal cortex, bilateral middle temporal lobe, bilateral cingulate, hippocampus) correlated with higher pain-related fear scores; and (4) decreases in pain-related fear associated with decreased connectivity between the amygdala and the motor and somatosensory cortex, cingulate, and frontal areas. Our data suggest that there are rapid changes in amygdala connectivity after an aggressive treatment program in children with chronic pain and intrinsic amygdala functional connectivity activity serving as a potential indicator of treatment response. PMID:24861582

  2. Respiratory complex I deficiency induces drought tolerance by impacting leaf stomatal and hydraulic conductances.

    PubMed

    Djebbar, Reda; Rzigui, Touhami; Pétriacq, Pierre; Mauve, Caroline; Priault, Pierrick; Fresneau, Chantal; De Paepe, Marianne; Florez-Sarasa, Igor; Benhassaine-Kesri, Ghouziel; Streb, Peter; Gakière, Bertrand; Cornic, Gabriel; De Paepe, Rosine

    2012-03-01

    To investigate the role of plant mitochondria in drought tolerance, the response to water deprivation was compared between Nicotiana sylvestris wild type (WT) plants and the CMSII respiratory complex I mutant, which has low-efficient respiration and photosynthesis, high levels of amino acids and pyridine nucleotides, and increased antioxidant capacity. We show that the delayed decrease in relative water content after water withholding in CMSII, as compared to WT leaves, is due to a lower stomatal conductance. The stomatal index and the abscisic acid (ABA) content were unaffected in well-watered mutant leaves, but the ABA/stomatal conductance relation was altered during drought, indicating that specific factors interact with ABA signalling. Leaf hydraulic conductance was lower in mutant leaves when compared to WT leaves and the role of oxidative aquaporin gating in attaining a maximum stomatal conductance is discussed. In addition, differences in leaf metabolic status between the mutant and the WT might contribute to the low stomatal conductance, as reported for TCA cycle-deficient plants. After withholding watering, TCA cycle derived organic acids declined more in CMSII leaves than in the WT, and ATP content decreased only in the CMSII. Moreover, in contrast to the WT, total free amino acid levels declined whilst soluble protein content increased in CMSII leaves, suggesting an accelerated amino acid remobilisation. We propose that oxidative and metabolic disturbances resulting from remodelled respiration in the absence of Complex I activity could be involved in bringing about the lower stomatal and hydraulic conductances. PMID:22002624

  3. Reducing Operator-Induced Machine Vibration Using a Complex Pole/zero Prefilter

    NASA Astrophysics Data System (ADS)

    INGRAM, G. A.; FRANCHEK, M. A.; CHIU, G. T.-C.

    2002-02-01

    A systematic prefilter design process for reducing operator-induced rigid body vibrations of rubber tire mounted machines is presented. The contribution of this work is the development of a systematic prefilter design process and interpretation of the results. The class of heavy equipment considered in this work are those machines having rigid body main frame vibrations dominated by linear dynamics. The reduction in machine vibrations is accomplished through the design of prefilters that reduce the machine resonant frequencies from the operator commands. The machine information required for the design process includes the bandwidth of the electro-hydraulic (E/H) valves and rigid body resonant frequencies of the machine mainframe. The prespecified performance in the design process is the desired attenuation of machine resonant frequencies which is related to the acceptable level of machine vibration. The design methodology has been applied to a telescopic boom lift to illustrate the procedure and the effectiveness of the design.

  4. Collective synchronization induced by epidemic dynamics on complex networks with communities

    NASA Astrophysics Data System (ADS)

    Yan, Gang; Fu, Zhong-Qian; Ren, Jie; Wang, Wen-Xu

    2007-01-01

    Much recent empirical evidence shows that community structure is ubiquitous in the real-world networks. In this paper we propose a growth model to create scale-free networks with the tunable strength (noted by Q ) of community structure and investigate the influence of community strength upon the collective synchronization induced by Susceptive-Infected-Recovery-Susceptive (SIRS) epidemiological process. Global and local synchronizability of the system is studied by means of an order parameter and the relevant finite-size scaling analysis is provided. The numerical results show that a phase transition occurs at Qc≃0.835 from global synchronization to desynchronization and the local synchronization is weakened in a range of intermediately large Q . Moreover, we study the impact of mean degree ⟨k⟩ upon synchronization on scale-free networks.

  5. LSPR biomolecular assay with high sensitivity induced by aptamer-antigen-antibody sandwich complex.

    PubMed

    Guo, Longhua; Kim, Dong-Hwan

    2012-01-15

    Herein we demonstrate a sensitive approach for protein detection based on peak shifts of localized surface plasmon resonance (LSPR) induced by aptamer-antigen-antibody sandwich structures. The applicability of the proposed method is demonstrated using human α-thrombin as a model analyte. While the binding of thrombin to its specific receptor, thrombin binding aptamer (TBA) modified on Au nanorods (AuNRs), causes a measurable LSPR shift, a subsequent binding of an anti-thrombin antibody to the captured thrombin can exhibit a nearly 150% amplification in the LSPR response. This enhanced signal essentially leads to an improvement of limit of detection (LOD) by more than one order of magnitude. In addition, the use of TBA as thrombin recognition units makes the biosensor reusable. The feasibility of the proposed method was further exploited by the detection of thrombin in human serum, opening the possibility of a real application for diagnostics and medical investigations. PMID:22099957

  6. The complex interactions between radiation induced non-targeted effects and cancer.

    PubMed

    Campa, Alessandro; Balduzzi, Maria; Dini, Valentina; Esposito, Giuseppe; Tabocchini, Maria Antonella

    2015-01-01

    Radiation induced non-targeted effects have been widely investigated in the last two decades for their potential impact on low dose radiation risk. In this paper we will give an overview of the most relevant aspects related to these effects, starting from the definition of the low dose scenarios. We will underline the role of radiation quality, both in terms of mechanisms of interaction with the biological matter and for the importance of charged particles as powerful tools for low dose effects investigation. We will focus on cell communication, representing a common feature of non-targeted effects, giving also an overview of cancer models that have explicitly considered such effects. PMID:24139968

  7. DNA and its cationic lipid complexes induce CpG motif-dependent activation of murine dendritic cells

    PubMed Central

    Yoshinaga, Takaharu; Yasuda, Kei; Ogawa, Yoshiyuki; Nishikawa, Makiya; Takakura, Yoshinobu

    2007-01-01

    Unmethylated CpG motifs in bacterial DNA, but not in vertebrate DNA, are known to trigger an inflammatory response of antigen-presenting cells (APC). In this study, we investigated the cytokine release from murine dendritic cells (DC) by the addition of various types of DNA in the free or complexed form with cationic lipids. Naked plasmid DNA and Escherichia coli DNA with immunostimulatory unmethylated CpG motifs induced pro-inflammatory cytokine secretion from granulocyte–macrophage colony-stimulating factor (GM-CSF)-cultured bone marrow-derived DC and the DC cell-line, DC2.4 cells, though vertebrate calf thymus DNA (CT DNA) with less CpG motifs did not. These characteristics differed from mouse peritoneal resident macrophages that do not respond to any naked DNA. The amount of cytokines released from the DC was significantly increased by complex formation with cationic lipids when CpG-motif positive DNAs were used. Unlike murine macrophages or Flt-3 L cultured DC, GM-CSF DC did not release inflammatory cytokines in response to the addition of CT DNA/cationic lipid complex, suggesting that the activation is completely dependent on CpG motifs. Taken together, the results of the present study demonstrate that murine DC produce pro-inflammatory cytokines upon stimulation with CpG-containing DNAs and the responses are enhanced by cationic lipids. These results also suggest that DC are the major cells that respond to naked CpG DNA in vivo, although both DC and macrophages will release inflammatory cytokines after the administration of a DNA/cationic lipid complex. PMID:17199803

  8. Pharmacological inhibition of polycomb repressive complex-2 activity induces apoptosis in human colon cancer stem cells

    PubMed Central

    Benoit, Yannick D.; Witherspoon, Mavee S.; Laursen, Kristian B.; Guezguez, Amel; Beauséjour, Marco; Beaulieu, Jean-Francois; Lipkin, Steven M.; Gudas, Lorraine J.

    2013-01-01

    Colorectal cancer is among the leading causes of cancer death in the USA. The polycomb repressive complex 2 (PRC2), including core components SUZ12 and EZH2, represents a key epigenetic regulator of digestive epithelial cell physiology and was previously shown to promote deleterious effects in a number of human cancers, including colon. Using colon cancer stem cells (CCSC) isolated from human primary colorectal tumors, we demonstrate that SUZ12 knockdown and treatment with DZNep, one of the most potent EZH2 inhibitors, increase apoptosis levels, marked by decreased Akt phosphorylation, in CCSCs, while embryonic stem (ES) cell survival is not affected. Moreover, DZNep treatments lead to increased PTEN expression in these highly tumorigenic cells. Taken together, our findings suggest that pharmacological inhibition of PRC2 histone methyltransferase activity may constitute a new, epigenetic therapeutic strategy to target highly tumorigenic and metastatic colon cancer stem cells. PMID:23588203

  9. Magnetic Field Induced Shear Flow in a Strongly Coupled Complex Plasma

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, P.; Konopka, U.; Jiang, K.; Morfill, G.

    2011-11-01

    We address an experimental observation of shear flow of micron sized dust particles in a strongly coupled complex plasma in presence of a homogeneous magnetic field. Two concentric Aluminum rings of different size are placed on the lower electrode of a radio frequency (rf) parallel plate discharge. The modified local sheath electric field is pointing outward/inward close to the inner/outher ring, respectively. The microparticles, confined by the rings and subject to an ion wind that driven by the local sheath electric field and deflected by an externally applied magnetic field, start flowing in azimuthal direction. Depending upon the rf amplitudes on the electrodes, the dust layers show rotation in opposite direction at the edges of the ring-shaped cloud resulting a strong shear in its center. MD simulations shows a good agreement with the experimental results.

  10. Proton transfer induced by receding water in Glycine---(Water)2 Complex

    NASA Astrophysics Data System (ADS)

    Pathak, Rajeev

    2011-03-01

    We investigate molecular co-operativity in the zwitterionic configuration of Glycine (Gly) with two proximal water molecules, Gly---(Water)2 , by deliberately making one of the water molecules recede from the remaining complex. The consequent intra-molecular proton transfer that renders the zwitterionic configuration into a neutral one is viewed under two scalar field descriptors: Molecular Electrostatic Potential (MESP), reflecting the modifications in the environment and the HOMO (highest occupied molecular orbital) electron density. We quantify the process further by energetics, through a many-body analysis of the interaction energy as well as salient IR spectral signatures associated with the proton-transfer. While we employ the decent MP2/aug-cc-pvDZ level of theory to seek optimal structures, it is gratifying that a prescription within density functional theory (DFT) also provides a reliable description of this process.

  11. A novel manganese complex selectively induces malignant glioma cell death by targeting mitochondria.

    PubMed

    Geng, Ji; Li, Jing; Huang, Tao; Zhao, Kaidi; Chen, Qiuyun; Guo, Wenjie; Gao, Jing

    2016-09-01

    Despite advances in treatment, malignant glioma commonly exhibits recurrence, subsequently leading to a poor prognosis. As manganese (Mn) compounds can be transported by the transferrin‑transferrin receptor system, the present study synthesized and examined the potential use of Adpa‑Mn as a novel antitumor agent. Adpa‑Mn time and dose‑dependently inhibited U251 and C6 cell proliferation; however, it had little effect on normal astrocytes. Apoptosis was significantly elevated following treatment with Adpa‑Mn, as detected by chromatin condensation, Annexin V/propidium iodide staining, cytochrome c release from mitochondria to the cytoplasm, and the activation of caspases‑9, ‑7 and ‑3 and poly (ADP‑ribose) polymerase. In addition, Adpa‑Mn enhanced fluorescence intensity of monodansylcadaverine and elevated the expression levels of the autophagy‑related protein microtubule‑associated protein 1 light chain 3. Pretreatment with the autophagy inhibitors 3‑methyladenine and chloroquine enhanced Adpa‑Mn‑induced cell inhibition, thus indicating that autophagy has an essential role in this process. Furthermore, evidence of mitochondrial dysfunction was detected in the Adpa‑Mn‑treated group, including disrupted membrane potential, elevated levels of reactive oxygen species (ROS) and depleted adenosine triphosphate. Conversely, treatment with the mitochondrial permeability transition inhibitor cyclosporin A reversed Adpa‑Mn‑induced ROS production, mitochondrial damage and cell apoptosis, thus suggesting that Adpa‑Mn may target the mitochondria. Taken together, these data suggested that Adpa‑Mn may be considered for use as a novel anti‑glioma therapeutic option. PMID:27432745

  12. Alcohol--Induced Polyelectrolyte-Surfactant Complex Coacervate Systems: Characterization and Applications in Enzyme and Protein Extraction

    NASA Astrophysics Data System (ADS)

    Nejati Moshtaghin, Mahboubeh

    The focus of this thesis is to achieve a better understanding of the newly discovered surfactant-polyelectrolyte complex coacervate (SPCC) systems induced by fluoroalcohol/acid as well as short chain aliphatic alcohol; and to elucidate their applications in extraction and enrichment of proteins and enzyme. We have discovered that fluoroalcohols and --acids induce complex coacervation and phase separation in the aqueous mixtures of oppositely charged anionic polyelectrolytes; specifically, sodium salts of polyacrylic acid and polymethacrylic acid and cationic surfactant (cetyltrimethylammonium bromide, CTAB) over a broad range of concentrations of mole fractions of the oppositely charged amphiphiles. Accordingly, these new classes of coacervators will significantly broaden the scope and facilitate engineering of new coacervate phases. Toward these goals, we have inspected the formation of surfactant-polyelectrolyte complex coacervates in the presence of fluoroalcohols namely hexafluoroisopropanol (HFIP) and Trifluoroethanol (TFE). Furthermore, the extent of coacervation as a function of concentrations the system components, and charge ratios of the oppositely charged amphiphiles has been investigated. Polyelectrolytes are considered to be milder reagents, as compared to surfactants, regarding proteins denaturation. This highlights the importance of a detailed investigation of the efficiency of our coacervate systems for extraction and preconcentration of proteins and enzymes, especially, when the biological activity of the extracted proteins needs to be maintained based on the objectives mentioned above, the results of the investigations have been organized in four chapters. In Chapter II, the phase behavior of the FA-SPCC will be investigated. The objective is to examine the phase behavior and phase properties with respect to the extent of coacervation in different solution conditions. In particular, the effects of different solution variables such as concentration

  13. Dopaminergic inhibition by G9a/Glp complex on tyrosine hydroxylase in nerve injury-induced hypersensitivity.

    PubMed

    Wang, Nan; Shen, Xiaofeng; Bao, Senzhu; Feng, Shan-Wu; Wang, Wei; Liu, Yusheng; Wang, Yiquan; Wang, Xian; Guo, Xirong; Shen, Rong; Wu, Haibo; Lei, Liming; Xu, Shiqin; Wang, Fuzhou

    2016-01-01

    The neural balance between facilitation and inhibition determines the final tendency of central sensitization. Nerve injury-induced hypersensitivity was considered as the results from the enhanced ascending facilitation and the diminished descending inhibition. The role of dopaminergic transmission in the descending inhibition has been well documented, but its underlying molecular mechanisms are unclear. Previous studies demonstrated that the lysine dimethyltransferase G9a/G9a-like protein (Glp) complex plays a critical role in cocaine-induced central plasticity, and given cocaine's role in the nerve system is relied on its function on dopamine system, we herein proposed that the reduced inhibition of dopaminergic transmission was from the downregulation of tyrosine hydroxylase expression by G9a/Glp complex through methylating its gene Th After approval by the Animal Care and Use Committee, C57BL/6 mice were used for pain behavior using von Frey after spared nerve injury, and Th CpG islands methylation was measured using bisulfite sequencing at different nerve areas. The inhibitor of G9a/Glp, BIX 01294, was administered intraventricularly daily with bolus injection. The protein levels of G9a, Glp, and tyrosine hydroxylase were measured with immunoblotting. Dopamine levels were detected using high-performance liquid chromatography. The expression of G9a but not Glp was upregulated in ventral tegmental area at post-injury day 4 till day 49 (the last day of the behavioral test). Correspondingly, the Th CpG methylation is increased, but the tyrosine hydroxylase expression was downregulated and the dopamine level was decreased. After the intracerebroventriclar injection of BIX 01294 since the post-injury days 7 and 14 for consecutive three days, three weeks, and six weeks, the expression of tyrosine hydroxylase was upregulated with a significant decrease in Th methylation and increase in dopamine level. Moreover, the pain after G9a/Glp inhibitor was attenuated

  14. Dopaminergic inhibition by G9a/Glp complex on tyrosine hydroxylase in nerve injury-induced hypersensitivity

    PubMed Central

    Wang, Nan; Shen, Xiaofeng; Bao, Senzhu; Feng, Shan-Wu; Wang, Wei; Liu, Yusheng; Wang, Yiquan; Wang, Xian; Guo, Xirong; Shen, Rong; Wu, Haibo; Lei, Liming; Wang, Fuzhou

    2016-01-01

    The neural balance between facilitation and inhibition determines the final tendency of central sensitization. Nerve injury-induced hypersensitivity was considered as the results from the enhanced ascending facilitation and the diminished descending inhibition. The role of dopaminergic transmission in the descending inhibition has been well documented, but its underlying molecular mechanisms are unclear. Previous studies demonstrated that the lysine dimethyltransferase G9a/G9a-like protein (Glp) complex plays a critical role in cocaine-induced central plasticity, and given cocaine’s role in the nerve system is relied on its function on dopamine system, we herein proposed that the reduced inhibition of dopaminergic transmission was from the downregulation of tyrosine hydroxylase expression by G9a/Glp complex through methylating its gene Th. After approval by the Animal Care and Use Committee, C57BL/6 mice were used for pain behavior using von Frey after spared nerve injury, and Th CpG islands methylation was measured using bisulfite sequencing at different nerve areas. The inhibitor of G9a/Glp, BIX 01294, was administered intraventricularly daily with bolus injection. The protein levels of G9a, Glp, and tyrosine hydroxylase were measured with immunoblotting. Dopamine levels were detected using high-performance liquid chromatography. The expression of G9a but not Glp was upregulated in ventral tegmental area at post-injury day 4 till day 49 (the last day of the behavioral test). Correspondingly, the Th CpG methylation is increased, but the tyrosine hydroxylase expression was downregulated and the dopamine level was decreased. After the intracerebroventriclar injection of BIX 01294 since the post-injury days 7 and 14 for consecutive three days, three weeks, and six weeks, the expression of tyrosine hydroxylase was upregulated with a significant decrease in Th methylation and increase in dopamine level. Moreover, the pain after G9a/Glp inhibitor was attenuated

  15. The Stress-Induced Atf3-Gelsolin Cascade Underlies Dendritic Spine Deficits in Neuronal Models of Tuberous Sclerosis Complex

    PubMed Central

    Nie, Duyu; Chen, Zehua; Ebrahimi-Fakhari, Darius; Di Nardo, Alessia; Julich, Kristina; Robson, Victoria K.; Cheng, Yung-Chih; Woolf, Clifford J.; Heiman, Myriam

    2015-01-01

    Hyperactivation of the mechanistic target of rapamycin (mTOR) kinase, as a result of loss-of-function mutations in tuberous sclerosis complex 1 (TSC1) or TSC2 genes, causes protein synthesis dysregulation, increased cell size, and aberrant neuronal connectivity. Dysregulated synthesis of synaptic proteins has been implicated in the pathophysiology of autism spectrum disorder (ASD) associated with TSC and fragile X syndrome. However, cell type-specific translational profiles in these disease models remain to be investigated. Here, we used high-fidelity and unbiased Translating Ribosome Affinity Purification (TRAP) methodology to purify ribosome-associated mRNAs and identified translational alterations in a rat neuronal culture model of TSC. We find that expression of many stress and/or activity-dependent proteins is highly induced while some synaptic proteins are repressed. Importantly, transcripts for the activating transcription factor-3 (Atf3) and mitochondrial uncoupling protein-2 (Ucp2) are highly induced in Tsc2-deficient neurons, as well as in a neuron-specific Tsc1 conditional knock-out mouse model, and show differential responses to the mTOR inhibitor rapamycin. Gelsolin, a known target of Atf3 transcriptional activity, is also upregulated. shRNA-mediated block of Atf3 induction suppresses expression of gelsolin, an actin-severing protein, and rescues spine deficits found in Tsc2-deficient neurons. Together, our data demonstrate that a cell-autonomous program consisting of a stress-induced Atf3-gelsolin cascade affects the change in dendritic spine morphology following mTOR hyperactivation. This previously unidentified molecular cascade could be a therapeutic target for treating mTORopathies. SIGNIFICANCE STATEMENT Tuberous sclerosis complex (TSC) is a genetic disease associated with epilepsy and autism. Dysregulated protein synthesis has been implicated as a cause of this disease. However, cell type-specific translational profiles that are aberrant in this

  16. Complex source mechanisms of mining-induced seismic events - implications for surface effects

    NASA Astrophysics Data System (ADS)

    Orlecka-Sikora, B.; Cesca, S.; Lasocki, S.; Rudzinski, L.; Lizurek, L.; Wiejacz, P.; Urban, P.; kozlowska, M.

    2012-04-01

    The seismicity of Legnica-Głogów Copper District (LGCD) is induced by mining activities in three mines: Lubin, Rudna and Polkowice-Sieroszowice. Ground motion caused by strong tremors might affect local infrastructure. "Żelazny Most" tailings pond, the biggest structure of this type in Europe, is here under special concern. Due to surface objects protection, Rudna Mine has been running ground motion monitoring for several years. From June 2010 to June 2011 unusually strong and extensive surface impact has been observed for 6 mining tremors induced in one of Rudna mining sections. The observed peak ground acceleration (PGA) for both horizontal and vertical component were in or even beyond 99% confidence interval for prediction. The aim of this paper is analyze the reason of such unusual ground motion. On the basis of registrations from Rudna Mine mining seismological network and records from Polish Seismological Network held by the Institute of Geophysics Polish Academy of Sciences (IGF PAN), the source mechanisms of these 6 tremors were calculated using a time domain moment tensor inversion. Furthermore, a kinematic analysis of the seismic source was performed, in order to determine the rupture planes orientations and rupture directions. These results showed that in case of the investigated tremors, point source models and shear fault mechanisms, which are most often assumed in mining seismology, are invalid. All analyzed events indicate extended sources with non-shear mechanism. The rapture planes have small dip angles and the rupture starts at the tremors hypocenter and propagates in the direction opposite to the plane dip. The tensional component plays here also big role. These source mechanisms well explain such observed strong ground motion, and calculated synthetic PGA values well correlates with observed ones. The relationship between mining tremors were also under investigation. All subsequent tremors occurred in the area of increased stress due to

  17. Cooperation-induced topological complexity: a promising road to fault tolerance and hebbian learning.

    PubMed

    Turalska, Malgorzata; Geneston, Elvis; West, Bruce J; Allegrini, Paolo; Grigolini, Paolo

    2012-01-01

    According to an increasing number of researchers intelligence emerges from criticality as a consequence of locality breakdown and long-range correlation, well known properties of phase transition processes. We study a model of interacting units, as an idealization of real cooperative systems such as the brain or a flock of birds, for the purpose of discussing the emergence of long-range correlation from the coupling of any unit with its nearest neighbors. We focus on the critical condition that has been recently shown to maximize information transport and we study the topological structure of the network of dynamically linked nodes. Although the topology of this network depends on the arbitrary choice of correlation threshold, namely the correlation intensity selected to establish a link between two nodes; the numerical calculations of this paper afford some important indications on the dynamically induced topology. The first important property is the emergence of a perception length as large as the flock size, thanks to some nodes with a large number of links, thus playing the leadership role. All the units are equivalent and leadership moves in time from one to another set of nodes, thereby insuring fault tolerance. Then we focus on the correlation threshold generating a scale-free topology with power index ν ≈ 1 and we find that if this topological structure is selected to establish consensus through the linked nodes, the control parameter necessary to generate criticality is close to the critical value corresponding to the all-to-all coupling condition. We find that criticality in this case generates also a third state, corresponding to a total lack of consensus. However, we make a numerical analysis of the dynamically induced network, and we find that it consists of two almost independent structures, each of which is equivalent to a network in the all-to-all coupling condition. This observation confirms that cooperation makes the system evolve toward

  18. Edifice and substrata deformation induced by intrusive complexes and gravitational loading in the Mull volcano (Scotland)

    NASA Astrophysics Data System (ADS)

    Mathieu, Lucie; Vries, Benjamin Van Wyk De

    2009-12-01

    It is likely that the structure of a volcanic edifice can be significantly modified by deformation caused by large, shallow intrusions. Such deformation may interact with that caused by volcano loading. We explore such intrusion-related and loading-related deformation with field evidence and analogue models. To do this we have chosen the eroded Palaeogene Mull volcano (Scotland) that had a major edifice, has well exposed intrusions and significant deformation. There are thin Mesozoic sedimentary rocks forming ductile layers below the volcano, but their thickness is insufficient to allow the gravitational spreading of the volcanic edifice, especially when considering that a thick lava pile covers them. Thus intrusive push may have been the driving force for deformation. The Mull activity migrated toward the northwest, forming three successive intrusive complexes (Centres 1, 2 and 3). Our detailed fieldwork reveals that deformation due to these was accommodated on three levels; along thrust planes in lava sequences, along a décollement located in a thin clay-rich sediment succession and in basement schists. A relative chronology has been established between different groups of structures using dyke and sill cross-cutting relationships. Centre 1 is surrounded by a fold and thrust belt leading to radial expansion. In contrast, Centre 2 and 3 are connected to thrusts located to the south and east, bounded by strike-slip faults, leading to expansion to the southeast. The migration of centres and the directed sliding of the edifice may be related to the presence to the southeast of low-resistance Dalradian basement that failed significantly during growth of Centres 2 and 3. To study the observed relationships we have carried out scaled analogue models. Models are made with fine powder intruded by a viscous magma analogue. The models show an intimate relationship between intrusion growth, uplift of the volcano and subsequent flank sliding. The structures produced can be

  19. Electrostatically-induced complex dynamics in viscous liquid film flows down the exterior of a cylinder

    NASA Astrophysics Data System (ADS)

    Wray, Alexander; Papageorgiou, Demetrios; Matar, Omar

    2011-11-01

    Annular flows on both the inner and outer walls of cylinders have a significant number of practical applications, from printing to fluid stabilisation to the augmentation of heat and mass transfer. It is important to understand the spatiotemporal dynamics of the interface in order to facilitate the possible control of the flow and efficiency of underlying processes. We investigate the evolution and stability of a viscous fluid layer wetting the surface of a cylinder and surrounded by a conductive gas. The inner cylinder is an electrode kept at constant voltage. A second concentric electrode, whose potential is allowed to vary as a function of both space and time, encloses the system. This induces electrostatic forces at the interface in competition to surface tension and viscous stresses. Asymptotic methods are used to derive several systems governing the interfacial position and charge accumulation. Two canonical sets of equations are derived, one valid for long-wave systems of moderate conductivity (a coupled Craster-Matar type system) and one valid for thin films of high conductivity (a Benney-type system). The resulting systems and their stabilities are investigated both analytically and numerically to compute travelling wave and transient simulations. EPSRC Grant number EP/E046029/1.

  20. Coherence effects in the ultra-intense laser-induced ultrafast response of complex atoms

    NASA Astrophysics Data System (ADS)

    Li, Yongqiang; Yuan, Jianmin

    2016-05-01

    Both coherent pumping and energy relaxation play important roles in understanding physical processes of ultra-intense coherent light-matter interactions. Here, using a large-scale quantum master equation approach, we describe dynamical processes of practical open quantum systems driven by both coherent and stochastic interactions. As examples, two typical cases of light-matter interactions are studied. First, we investigate coherent dynamics of inner-shell electrons of a neon gas irradiated by a high intensity X-ray laser along with vast number of decaying channels. In these single-photon dominated processes, we find that, due to coherence-induced Rabi oscillations and power broadening effects, the photon absorptions of a neon gas can be suppressed resulting in differences in ionization processes and final ion-stage distributions. Second, we take helium as an example of multi-photon and multichannel interference dominated electron dynamics, by investigating the transient absorption of an isolated atto-second pulse in the presence of a femto-second infrared laser pulse.

  1. Using molecular tools to decipher the complex world of plant resistance inducers: an apple case study.

    PubMed

    Dugé de Bernonville, Thomas; Marolleau, Brice; Staub, Johan; Gaucher, Matthieu; Brisset, Marie-Noëlle

    2014-11-26

    Exogenous application of plant resistance inducers (PRIs) able to activate plant defenses is an interesting approach for new integrated pest management practices. The full integration of PRIs into agricultural practices requires methods for the fast and objective upstream screening of efficient PRIs and optimization of their application. To select active PRIs, we used a molecular tool as an alternative to methods involving plant protection assays. The expressions of 28 genes involved in complementary plant defense mechanisms were simultaneously determined by quantitative real-time PCR in PRI-treated tissues. Using a set of 10 commercial preparations and considering the pathosystem apple/Erwinia amylovora, this study shows a strong correlation between defense activation and protection efficiency in controlled conditions, thus enabling the easy identification of promising PRIs in fire blight protection. Hence this work clearly highlights the benefits of using a molecular tool to discriminate nonactive PRI preparations and provides useful molecular markers for the optimization of their use in orchard. PMID:25372566

  2. HIV-1 Gag Blocks Selenite-Induced Stress Granule Assembly by Altering the mRNA Cap-Binding Complex

    PubMed Central

    Cinti, Alessandro; Le Sage, Valerie; Ghanem, Marwan

    2016-01-01

    ABSTRACT Stress granules (SGs) are dynamic accumulations of stalled preinitiation complexes and translational machinery that assemble under stressful conditions. Sodium selenite (Se) induces the assembly of noncanonical type II SGs that differ in morphology, composition, and mechanism of assembly from canonical SGs. Se inhibits translation initiation by altering the cap-binding activity of eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4EBP1). In this work, we show that human immunodeficiency virus type 1 (HIV-1) Gag is able to block the assembly of type II noncanonical SGs to facilitate continued Gag protein synthesis. We demonstrate that expression of Gag reduces the amount of hypophosphorylated 4EBP1 associated with the 5′ cap potentially through an interaction with its target, eIF4E. These results suggest that the assembly of SGs is an important host antiviral defense that HIV-1 has evolved for inhibition through several distinct mechanisms. PMID:27025252

  3. Role of CDK5/cyclin complexes in ischemia-induced death and survival of renal tubular cells

    PubMed Central

    Guevara, Tatiana; Sancho, Mónica; Pérez-Payá, Enrique; Orzáez, Mar

    2014-01-01

    Ischemia reperfusion processes induce damage in renal tubules and compromise the viability of kidney transplants. Understanding the molecular events responsible for tubule damage and recovery would help to develop new strategies for organ preservation. CDK5 has been traditionally considered a neuronal kinase with dual roles in cell death and survival. Here, we demonstrate that CDK5 and their regulators p35/p25 and cyclin I are also expressed in renal tubular cells. We show that treatment with CDK inhibitors promotes the formation of pro-survival CDK5/cyclin I complexes and enhances cell survival upon an ischemia reperfusion pro-apoptotic insult. These findings support the benefit of treating with CDK inhibitors for renal preservation, assisting renal tubule protection. PMID:24675881

  4. Phase-induced amplitude apodization complex mask coronagraph mask fabrication, characterization, and modeling for WFIRST-AFTA

    NASA Astrophysics Data System (ADS)

    Kern, Brian; Guyon, Olivier; Belikov, Ruslan; Wilson, Daniel; Muller, Richard; Sidick, Erkin; Balasubramanian, Bala; Krist, John; Poberezhskiy, Ilya; Tang, Hong

    2016-01-01

    This work describes the fabrication, characterization, and modeling of a second-generation occulting mask for a phase-induced amplitude apodization complex mask coronagraph, designed for use on the WFIRST-AFTA mission. The mask has many small features (˜micron lateral scales) and was fabricated at the Jet Propulsion Laboratory Microdevices Laboratory, then characterized using a scanning electron microscope, atomic force microscope, and optical interferometric microscope. The measured fabrication errors were then fed to a wavefront control model which predicts the contrast performance of a full coronagraph. The expected coronagraphic performance using this mask is consistent with observing ˜15 planetary targets with WFIRST-AFTA in a reasonable time (<1 day/target).

  5. Constitutive model for flake graphite cast iron automotive brake discs: induced anisotropic damage model under complex loadings

    NASA Astrophysics Data System (ADS)

    Augustins, L.; Billardon, R.; Hild, F.

    2016-01-01

    The present paper details an elasto-viscoplastic constitutive model for automotive brake discs made of flake graphite cast iron. In a companion paper (Augustins et al. in Contin Mech Thermodyn, 2015), the authors proposed a one-dimensional setting appropriate for representing the complex behavior of the material (i.e., asymmetry between tensile and compressive loadings) under anisothermal conditions. The generalization of this 1D model to 3D cases on a volume element and the associated challenges are addressed. A direct transposition is not possible, and an alternative solution without unilateral conditions is first proposed. Induced anisotropic damage and associated constitutive laws are then introduced. The transition from the volume element to the real structure and the numerical implementation require a specific basis change. Brake disc simulations with this constitutive model show that unilateral conditions are needed for the friction bands. A damage deactivation procedure is therefore defined.

  6. Anergy in CD4 Memory T Lymphocytes: II. Abrogation of TCR-induced Formation of Membrane Signaling Complexes1

    PubMed Central

    Lee, William T.; Prasad, Aparna; Watson, Andrew R. O.

    2012-01-01

    Memory and naive CD4 T cells have unique regulatory pathways for self/non-self discrimination. A memory cell specific regulatory pathway was revealed using superantigens to trigger the TCR. Upon stimulation by bacterial superantigens, like staphylococcal enterotoxin B (SEB), TCR proximal signaling is impaired leading to clonal tolerance (anergy). In the present report, we show that memory cell anergy results from the sequestration of the protein tyrosine kinase ZAP-70 away from the TCR/CD3ζ chain. During SEB-induced signaling, ZAP-70 is excluded from both detergent-resistant membrane microdomains and the immunological synapse, thus blocking downstream signaling. We also show that the mechanism underlying memory cell anergy must involve Fyn kinase, given that the suppression of Fyn activity restores the movement of ZAP-70 to the immunological synapse, TCR proximal signaling, and cell proliferation. Thus, toleragens, including microbial toxins, may modulate memory responses by targeting the organizational structure of memory cell signaling complexes. PMID:22663768

  7. Rhinovirus infection induces major histocompatibility complex class I and costimulatory molecule upregulation on respiratory epithelial cells.

    PubMed

    Papi, A; Stanciu, L A; Papadopoulos, N G; Teran, L M; Holgate, S T; Johnston, S L

    2000-05-01

    Human respiratory epithelial cells may act as antigen-presenting cells during respiratory viral infections. In addition to major histocompatibility complex (MHC) molecules, antigen presentation requires participation of costimulatory molecules. Here the authors investigated class I and class II antigens and B7-1 and B7-2 costimulatory molecule expression in human A549 pulmonary epithelial cells and primary bronchial epithelial cells (HBECs) at baseline and after rhinovirus infection. Constitutive expression of MHC class I and B7-1 molecules was observed on both cell types. MHC class I molecules were up-regulated by rhinovirus infection, while B7-1 was up-regulated only on A549 cells. B7-2 molecules were constitutively expressed at a low level and were up-regulated by rhinovirus only on HBECs. Rhinovirus induction of antigen-presenting molecule expression on A549 cells was accompanied by cellular activation in terms of induction of release of the chemokines RANTES and Groalpha. These data show that respiratory epithelium expresses full antigen-presentation machinery and that rhinovirus infection up-regulates this expression. PMID:10823784

  8. New Insights into Molecular Mechanisms of Immune Complex-Induced Injury in Lung.

    PubMed

    Ward, Peter A; Fattahi, Fatemeh; Bosmann, Markus

    2016-01-01

    While the phlogistic activities of IgM or IgG immune complexes (ICs) have been well established as complement-activating agents and seem likely to play important roles in humans with vasculitis, certain types of glomerulonephritis as well as in a variety of autoimmune diseases, the predominant clinical strategies have involved the use of immunosuppressive or anti-inflammatory drugs. Over the past decade, new insights into molecular events developing during IC models in rodents have identified new phlogistic products that may be candidates for therapeutic blockade. Extracellular histones, located in the web-like structures of neutrophil extracellular traps, are released from complement-activated polymorphonuclear neutrophils (PMNs) downstream of IC deposition. Extracellular histones appear to be a new class of highly tissue-damaging products derived from complement-activated PMNs. Histones have also been discovered in cell-free broncho-alveolar lavage fluids from humans with acute respiratory distress syndrome (ARDS). Recent studies emphasize that in the setting of ARDS-like reactions in rodents, extracellular histones are released and are exceedingly proinflammatory, tissue damaging, and prothrombotic. Such studies suggest that in humans with ARDS, extracellular histones may represent therapeutic targets for blockade. PMID:27014266

  9. New Insights into Molecular Mechanisms of Immune Complex-Induced Injury in Lung

    PubMed Central

    Ward, Peter A.; Fattahi, Fatemeh; Bosmann, Markus

    2016-01-01

    While the phlogistic activities of IgM or IgG immune complexes (ICs) have been well established as complement-activating agents and seem likely to play important roles in humans with vasculitis, certain types of glomerulonephritis as well as in a variety of autoimmune diseases, the predominant clinical strategies have involved the use of immunosuppressive or anti-inflammatory drugs. Over the past decade, new insights into molecular events developing during IC models in rodents have identified new phlogistic products that may be candidates for therapeutic blockade. Extracellular histones, located in the web-like structures of neutrophil extracellular traps, are released from complement-activated polymorphonuclear neutrophils (PMNs) downstream of IC deposition. Extracellular histones appear to be a new class of highly tissue-damaging products derived from complement-activated PMNs. Histones have also been discovered in cell-free broncho-alveolar lavage fluids from humans with acute respiratory distress syndrome (ARDS). Recent studies emphasize that in the setting of ARDS-like reactions in rodents, extracellular histones are released and are exceedingly proinflammatory, tissue damaging, and prothrombotic. Such studies suggest that in humans with ARDS, extracellular histones may represent therapeutic targets for blockade. PMID:27014266

  10. Perceptual conflict-induced late positive complex in a modified Stroop task.

    PubMed

    Li, Guochao; Wang, Suiping; Duan, Yixing; Zhu, Zude

    2013-05-10

    To investigate the functional significance of the late positive complex (LPC) in the Stroop task, the present study recruited 22 participants and had them report the color of words in the classical Stroop task and the rotation state of words in a Rotation judgment task. Color words whose ink color was either congruent (CON) or incongruent (INCON) with the word's meaning were presented in both tasks. Consistent with previous studies, the N450 and LPC were observed in the Stroop task, accompanied by slowed reaction time (RT) in the INCON condition compared with the CON condition. Notably, a larger LPC was observed in the INCON condition than in the CON condition in the Rotation task, while RT and accuracy were comparable between the two conditions. Because the incongruence between ink color and word meaning was independent from the response, and neither influenced accuracy nor RT in the Rotation task, the results suggested that the LPC may have resulted from the perceptual conflict between ink color and word meaning. PMID:23416898

  11. Phenol Nitration Induced by an {Fe(NO)2}10 Dinitrosyl Iron Complex

    SciTech Connect

    N Tran; H Kalyvas; K Skodje; T Hayashi; P Moenne-Loccoz; P Callan; J Shearer; L Kirschenbaum; E Kim

    2011-12-31

    Cellular dinitrosyl iron complexes (DNICs) have long been considered NO carriers. Although other physiological roles of DNICs have been postulated, their chemical functionality outside of NO transfer has not been demonstrated thus far. Here we report the unprecedented dioxygen reactivity of a N-bound {l_brace}Fe(NO){sub 2}{r_brace}{sup 10} DNIC, [Fe(TMEDA)(NO){sub 2}] (1). In the presence of O{sub 2}, 1 becomes a nitrating agent that converts 2,4,-di-tert-butylphenol to 2,4-di-tert-butyl-6-nitrophenol via formation of a putative iron-peroxynitrite [Fe(TMEDA)(NO)(ONOO)] (2) that is stable below -80 C. Iron K-edge X-ray absorption spectroscopy on 2 supports a five-coordinated metal center with a bound peroxynitrite in a cyclic bidentate fashion. The peroxynitrite ligand of 2 readily decays at increased temperature or under illumination. These results suggest that DNICs could have multiple physiological or deleterious roles, including that of cellular nitrating agents.

  12. An SCF complex containing Fbxl12 mediates DNA damage-induced Ku80 ubiquitylation

    PubMed Central

    Postow, Lisa; Funabiki, Hironori

    2013-01-01

    The Ku heterodimer, composed of Ku70 and Ku80, is the initiating factor of the nonhomologous end joining (NHEJ) double-strand break (DSB) repair pathway. Ku is also thought to impede the homologous recombination (HR) repair pathway via inhibition of DNA end resection. Using the cell-free Xenopus laevis egg extract system, we had previously discovered that Ku80 becomes polyubiquitylated upon binding to DSBs, leading to its removal from DNA and subsequent proteasomal degradation. Here we show that the Skp1-Cul1-F box (SCF) E3 ubiquitin ligase complex is required for Ku80 ubiquitylation and removal from DNA. A screen for DSB-binding F box proteins revealed that the F box protein Fbxl12 was recruited to DNA in a DSB- and Ku-sensitive manner. Immunodepletion of Fbxl12 prevented Cul1 and Skp1 binding to DSBs and Ku80 ubiquitylation, indicating that Fbxl12 is the F box protein responsible for Ku80 substrate recognition. Unlike typical F box proteins, the F box of Fbxl12 was essential for binding to both Skp1 and its substrate Ku80. Besides Fbxl12, six other chromatin-binding F box proteins were identified in our screen of a subset of Xenopus F box proteins: β-TrCP, Fbh1, Fbxl19, Fbxo24, Fbxo28 and Kdm2b. Our study unveils a novel function for the SCF ubiquitin ligase in regulating the dynamic interaction between DNA repair machineries and DSBs. PMID:23324393

  13. Curcuminoid-phospholipid complex induces apoptosis in mammary epithelial cells by STAT-3 signaling

    PubMed Central

    Cucuzza, Laura Starvaggi; Motta, Massimiliano; Miretti, Silvia; Accornero, Paolo

    2008-01-01

    Curcumin (from the rhizome of Curcuma longa) is well documented for its medicinal properties in Indian and Chinese systems of medicine where it is widely used for the treatment of several diseases. Epidemiological observations are suggestive that curcumin consumption may reduce the risk of some form of cancers and provide other protective biological effects in humans. These biological properties have been attributed to curcuminoids that have been widely studied for their anti-inflammatory, anti-angiogenic, antioxidant, wound healing and anti-cancer effects. In this study we have investigated on the effect of a curcumin phospholipid complex on mammary epithelial cell viability. HC11 and BME-UV cell lines, validated models to study biology of normal, not tumoral, mammary epithelial cells, were used to analyse these effects. We report that curcumin acts on STAT-3 signal pathway to reduce cell viability and increase apoptosis evaluated by the the amount of activated caspase 3. Further it reduces MAPK and AKT activations. JSI-124, a STAT-3 inhibitor (100 nM) was able to block the negative effect of curcumin on cell viability and caspase 3 activation. Finally the negative effect of cucumin on cell viability has been impaired in STAT-3i HC11, where STAT-3 protein was greatly reduced by shRNA-interference. These results indicate that curcumin presents a potential adverse effect to normal mammary epithelial cells and that it has a specific effect on signal trasduction in mammary epithelium. PMID:19116450

  14. Dual effects of a homeopathic mineral complex on carrageenan-induced oedema in rats.

    PubMed

    Bertani, S; Lussignoli, S; Andrioli, G; Bellavite, P; Conforti, A

    1999-07-01

    Carrageenan oedema, a classical experimental model commonly used to test activity of anti-inflammatory drugs, was used to evaluate the therapeutic activity of a low-potency mineral complex (MC). The MC was administered in the right plantar surface of albino rats 60 min before, simultaneously and 30 min after injection of carrageenan, an irritant which causes a local, transitory increase of fluid volume. The administration of the MC 60 min before the injection of carrageenan primed the animal to enhanced inflammatory response to the irritant. The administration of MC contemporarily to carrageenan did not modify the kinetic and the extent of the oedema, while the administration of the MC 30 min after the induction of the oedema significantly reduced the early phase of the inflammatory reaction. This indicated that the therapeutic action of this MC is not due to conventional anti-inflammatory effect but to activation of endogenous regulatory mechanisms, a phenomenon which may be regarded as a simple application of the 'similia rule'. PMID:10449049

  15. Well-Defined Dinuclear Gold Complexes for Preorganization-Induced Selective Dual Gold Catalysis.

    PubMed

    Vreeken, Vincent; Broere, Daniël L J; Jans, Anne C H; Lankelma, Marianne; Reek, Joost N H; Siegler, Maxime A; van der Vlugt, Jarl Ivar

    2016-08-16

    The synthesis, reactivity, and potential of well-defined dinuclear gold complexes as precursors for dual gold catalysis are explored. Using the preorganizing abilities of the ditopic PN(H) P(iPr) (L(H) ) ligand, dinuclear Au(I) -Au(I) complex 1 and mixed-valent Au(I) -Au(III) complex 2 provide access to structurally characterized chlorido-bridged cationic species 3 and 4 upon halide abstraction. For 2, this transformation involves unprecedented two-electron oxidation of the redox-active ligand, generating a highly rigidified environment for the Au2 core. Facile reaction with phenylacetylene affords the σ,π-activated phenylacetylide complex 5. When applied in the dual gold heterocycloaddition of a urea-functionalized alkyne, well-defined precatalyst 3 provides high regioselectivities for the anti-Markovnikov product, even at low catalyst loadings, and outperforms common mononuclear Au(I) systems. This proof-of-concept demonstrates the benefit of preorganization of two gold centers to enforce selective non-classical σ,π-activation with bifunctional substrates. PMID:27430938

  16. Somatic mosaicism and allele complexity induced by CRISPR/Cas9 RNA injections in mouse zygotes

    PubMed Central

    Yen, Shuo-Ting; Zhang, Min; Deng, Jian Min; Usman, Shireen J.; Smith, Chad N.; Parker-Thornburg, Jan; Swinton, Paul G.; Martin, James F.; Behringer, Richard R.

    2014-01-01

    Tyrosinase is the rate-limiting enzyme for the production of melanin pigmentation. In the mouse and other animals, homozygous null mutations in the Tyrosinase gene (Tyr) result in the absence of pigmentation, i.e. albinism. Here we used the CRISPR/Cas9 system to generate mono- and bi-allelic null mutations in the Tyr locus by zygote injection of two single-guide and Cas9 RNAs. Injection into C57BL/6N wild-type embryos resulted in one completely albino founder carrying two different Tyr mutations. In addition, three pigmentation mosaics and fully pigmented littermates were obtained that transmitted new mutant Tyr alleles to progeny in test crosses with albinos. Injection into Tyr heterozygous (B6CBAF1/J × FVB/NJ) zygotes resulted in the generation of numerous albinos and also mice with a graded range of albino mosaicism. Deep sequencing revealed that the majority of the albinos and the mosaics had more than two new mutant alleles. These visual phenotypes and molecular genotypes highlight the somatic mosaicism and allele complexity in founders that occurs for targeted genes during CRISPR/Cas9-mediated mutagenesis by zygote injection in mice. PMID:24984260

  17. Enhanced Direct Major Histocompatibility Complex Class I Self-Antigen Presentation Induced by Chlamydia Infection

    PubMed Central

    Cram, Erik D.; Simmons, Ryan S.; Palmer, Amy L.; Hildebrand, William H.; Rockey, Daniel D.

    2015-01-01

    The direct major histocompatibility complex (MHC) class I antigen presentation pathway ensures intracellular peptides are displayed at the cellular surface for recognition of infected or transformed cells by CD8+ cytotoxic T lymphocytes. Chlamydia spp. are obligate intracellular bacteria and, as such, should be targeted by CD8+ T cells. It is likely that Chlamydia spp. have evolved mechanisms to avoid the CD8+ killer T cell responses by interfering with MHC class I antigen presentation. Using a model system of self-peptide presentation which allows for posttranslational control of the model protein's stability, we tested the ability of various Chlamydia species to alter direct MHC class I antigen presentation. Infection of the JY lymphoblastoid cell line limited the accumulation of a model host protein and increased presentation of the model-protein-derived peptides. Enhanced self-peptide presentation was detected only when presentation was restricted to defective ribosomal products, or DRiPs, and total MHC class I levels remained unaltered. Skewed antigen presentation was dependent on a bacterial synthesized component, as evidenced by reversal of the observed phenotype upon preventing bacterial transcription, translation, and the inhibition of bacterial lipooligosaccharide synthesis. These data suggest that Chlamydia spp. have evolved to alter the host antigen presentation machinery to favor presentation of defective and rapidly degraded forms of self-antigen, possibly as a mechanism to diminish the presentation of peptides derived from bacterial proteins. PMID:26597986

  18. A Vaccine Based on the Rhesus Cytomegalovirus UL128 Complex Induces Broadly Neutralizing Antibodies in Rhesus Macaques

    PubMed Central

    Wussow, Felix; Yue, Yujuan; Martinez, Joy; Deere, Jesse D.; Longmate, Jeff; Herrmann, Andreas

    2013-01-01

    Neutralizing antibodies (NAb) are important for interfering with horizontal transmission of human cytomegalovirus (HCMV) leading to primary and congenital HCMV infection. Recent findings have shown that a pentameric virion complex formed by the glycoproteins gH/gL, UL128, UL130, and UL131A (UL128C) is required for HCMV entry into epithelial/endothelial cells (Epi/EC) and is the target of potent NAb in HCMV-seropositive individuals. Using bacterial artificial chromosome technology, we have generated a modified vaccinia Ankara virus (MVA) that stably coexpresses all 5 rhesus CMV (RhCMV) proteins homologous to HCMV UL128C, termed MVA-RhUL128C. Coimmunoprecipitation confirmed the interaction of RhgH with the other 4 RhCMV subunits of the pentameric complex. All 8 RhCMV-naïve rhesus macaques (RM) vaccinated with MVA-RhUL128C developed NAb that blocked infection of monkey kidney epithelial cells (MKE) and rhesus fibroblasts. NAb titers induced by MVA-RhUL128C measured on both cell types at 2 to 6 weeks postvaccination were comparable to levels observed in naturally infected RM. In contrast, MVA expressing a subset of RhUL128C proteins or RhgB glycoprotein only minimally stimulated NAb that inhibited infection of MKE. In addition, following subcutaneous RhCMV challenge at 8 weeks postvaccination, animals vaccinated with MVA-RhUL128C showed reduced plasma viral loads. These results indicate that MVA expressing the RhUL128C induces NAb inhibiting RhCMV entry into both Epi/EC and fibroblasts and limits RhCMV replication in RM. This novel approach is the first step in developing a prophylactic HCMV vaccine designed to interfere with virus entry into major cell types permissive for viral replication, a required property of an effective vaccine. PMID:23152525

  19. Functional aspects of the EGF-induced MAP kinase cascade: a complex self-organizing system approach.

    PubMed

    Kosmidis, Efstratios K; Moschou, Vasiliki; Ziogas, Georgios; Boukovinas, Ioannis; Albani, Maria; Laskaris, Nikolaos A

    2014-01-01

    The EGF-induced MAP kinase cascade is one of the most important and best characterized networks in intracellular signalling. It has a vital role in the development and maturation of living organisms. However, when deregulated, it is involved in the onset of a number of diseases. Based on a computational model describing a "surface" and an "internalized" parallel route, we use systems biology techniques to characterize aspects of the network's functional organization. We examine the re-organization of protein groups from low to high external stimulation, define functional groups of proteins within the network, determine the parameter best encoding for input intensity and predict the effect of protein removal to the system's output response. Extensive functional re-organization of proteins is observed in the lower end of stimulus concentrations. As we move to higher concentrations the variability is less pronounced. 6 functional groups have emerged from a consensus clustering approach, reflecting different dynamical aspects of the network. Mutual information investigation revealed that the maximum activation rate of the two output proteins best encodes for stimulus intensity. Removal of each protein of the network resulted in a range of graded effects, from complete silencing to intense activation. Our results provide a new "vista" of the EGF-induced MAP kinase cascade, from the perspective of complex self-organizing systems. Functional grouping of the proteins reveals an organizational scheme contrasting the current understanding of modular topology. The six identified groups may provide the means to experimentally follow the dynamics of this complex network. Also, the vulnerability analysis approach may be used for the development of novel therapeutic targets in the context of personalized medicine. PMID:25372488

  20. Functional Aspects of the EGF-Induced MAP Kinase Cascade: A Complex Self-Organizing System Approach

    PubMed Central

    Kosmidis, Efstratios K.; Moschou, Vasiliki; Ziogas, Georgios; Boukovinas, Ioannis; Albani, Maria; Laskaris, Nikolaos A.

    2014-01-01

    The EGF-induced MAP kinase cascade is one of the most important and best characterized networks in intracellular signalling. It has a vital role in the development and maturation of living organisms. However, when deregulated, it is involved in the onset of a number of diseases. Based on a computational model describing a “surface” and an “internalized” parallel route, we use systems biology techniques to characterize aspects of the network’s functional organization. We examine the re-organization of protein groups from low to high external stimulation, define functional groups of proteins within the network, determine the parameter best encoding for input intensity and predict the effect of protein removal to the system’s output response. Extensive functional re-organization of proteins is observed in the lower end of stimulus concentrations. As we move to higher concentrations the variability is less pronounced. 6 functional groups have emerged from a consensus clustering approach, reflecting different dynamical aspects of the network. Mutual information investigation revealed that the maximum activation rate of the two output proteins best encodes for stimulus intensity. Removal of each protein of the network resulted in a range of graded effects, from complete silencing to intense activation. Our results provide a new “vista” of the EGF-induced MAP kinase cascade, from the perspective of complex self-organizing systems. Functional grouping of the proteins reveals an organizational scheme contrasting the current understanding of modular topology. The six identified groups may provide the means to experimentally follow the dynamics of this complex network. Also, the vulnerability analysis approach may be used for the development of novel therapeutic targets in the context of personalized medicine. PMID:25372488

  1. Optical Estimation of Depth Induced Wave Breaking Distributions over Complex Bathymetry

    NASA Astrophysics Data System (ADS)

    Keen, A. S.; Holman, R. A.

    2012-12-01

    Parametric depth-induced-breaking dissipation models have shown great skill at predicting time averaged wave heights across the surf zone. First proposed by Battjes & Janssen (1978), these models balance the incoming wave energy flux with a roller dissipation term. This roller dissipation term is estimated by calculating the dissipation for one characteristic broken wave and then multiplying this quantity by the fraction of broken waves. To describe the fraction of broken waves, a typical assumption asserts that wave heights are nearly Rayleigh distributed [Thornton & Guza (1983)] allowing a sea state to be described by only a few parameters. While many experiments have validated the cross shore wave height profiles, few field experiments have been performed to analyze the probability distribution of breaking wave heights over a barred beach profile. The goal of the present research is to determine the distribution of broken and unbroken wave heights across a natural barred beach profile. Field data collected during the Surf Zone Optics experiment (a Multi-disciplinary University Research Initiative) in Duck, North Carolina, consisted of an array of in-situ pressure sensors and optical remote sensing cameras. Sea surface elevation time series from the in-situ pressure sensors are used here to resolve wave height distributions at multiple locations across the surf zone. Breaking wave height distributions are resolved based upon a combination of the pressure sensor and optically based breaker detection algorithm. Since breaking is easily able to be tracked by video imaging, breaking waves are flagged in the sea surface elevation series and binned into a broken wave height distribution. Results of this analysis are compared with model predictions based upon the Battjes & Janssen (1978), Thornton & Guza (1983) and Janssen & Battjes (2007) models to assess the validity of each wave height distribution model.

  2. Field-Induced Slow Magnetic Relaxation in a Mononuclear Manganese(III)-Porphyrin Complex.

    PubMed

    Pascual-Álvarez, Alejandro; Vallejo, Julia; Pardo, Emilio; Julve, Miguel; Lloret, Francesc; Krzystek, J; Armentano, Donatella; Wernsdorfer, Wolfgang; Cano, Joan

    2015-11-23

    We report on a novel manganese(III)-porphyrin complex with the formula [Mn(III) (TPP)(3,5-Me2 pyNO)2 ]ClO4 ⋅CH3 CN (2; 3,5-Me2 pyNO=3,5-dimethylpyridine N-oxide, H2 TPP=5,10,15,20-tetraphenylporphyrin), in which the Mn(III) ion is six-coordinate with two monodentate 3,5-Me2 pyNO molecules and a tetradentate TPP ligand to build a tetragonally elongated octahedral geometry. The environment in 2 is responsible for the large and negative axial zero-field splitting (D=-3.8 cm(-1) ), low rhombicity (E/|D|=0.04) of the high-spin Mn(III) ion, and, ultimately, for the observation of slow magnetic-relaxation effects (Ea =15.5 cm(-1) at H=1000 G) in this rare example of a manganese-based single-ion magnet (SIM). Structural, magnetic, and electronic characterizations were carried out by means of single-crystal diffraction studies, variable-temperature direct- and alternating-current measurements and high-frequency and -field EPR spectroscopic analysis followed by quantum-chemical calculations. Slow magnetic-relaxation effects were also observed in the already known analogous compound [Mn(III) (TPP)Cl] (1; Ea =10.5 cm(-1) at H=1000 G). The results obtained for 1 and 2 are compared and discussed herein. PMID:26481722

  3. Laser-induced synthesis of a nanostructured polymer-like metal-carbon complexes

    NASA Astrophysics Data System (ADS)

    Arakelian, S.; Kutrovskaya, S.; Kucherik, A.; Osipov, A.; Povolotckaia, A.; Povolotskiy, A.; Manshina, A.

    2016-04-01

    Synthesis of nanotructured metal-carbon materials by laser irradiation is an actual branch of laser physics and nanotechnology. Laser sources with different pulse duration allow changing the heating rate with realization of different transition scenarios and synthesis materials with various physical properties. We study the process of the formation of nanostructured metal-clusters and complexes using laser irradiation of colloidal systems which were consisted of carbon micro- nanoparticles and nanoparticles of noble metals. For carbon nanoparticles synthesis we use the method of laser ablation in liquid. For the realization of different regimes of laser surface modification of the target (glassycarbon and shungite) and the formation of micro- nanoparticles in a liquid the YAG:Nd laser with a pulse duration from 0.5 ms up to 20 ms (pulse energy up to 50J) was applied. We have used the CW-laser with moderate intensity in liquid (water or ethanol) for nanoparticle of noble metals synthesis. Thus, colloidal systems were obtained by using CW-laser with λ = 1.06 μm, I ~ 105-6 W/cm2, and t = 10 min. The average size of resulting particles was approximately about 10 to 100 nm. The nanoparticle obtaining was provided in the colloidal solution with different laser parameters. In this work we have investigated the mechanism of the metal-carbon cluster formation during the process of irradiation of colloidal system which were consisted of separate carbon, silver and gold nanoparticles. This system was irradiated by nanosecond laser (100 ns) with average power up to 50W.

  4. Crowding Induces Complex Ergodic Diffusion and Dynamic Elongation of Large DNA Molecules

    PubMed Central

    Chapman, Cole D.; Gorczyca, Stephanie; Robertson-Anderson, Rae M.

    2015-01-01

    Despite the ubiquity of molecular crowding in living cells, the effects of crowding on the dynamics of genome-sized DNA are poorly understood. Here, we track single, fluorescent-labeled large DNA molecules (11, 115 kbp) diffusing in dextran solutions that mimic intracellular crowding conditions (0–40%), and determine the effects of crowding on both DNA mobility and conformation. Both DNAs exhibit ergodic Brownian motion and comparable mobility reduction in all conditions; however, crowder size (10 vs. 500 kDa) plays a critical role in the underlying diffusive mechanisms and dependence on crowder concentration. Surprisingly, in 10-kDa dextran, crowder influence saturates at ∼20% with an ∼5× drop in DNA diffusion, in stark contrast to exponentially retarded mobility, coupled to weak anomalous subdiffusion, with increasing concentration of 500-kDa dextran. Both DNAs elongate into lower-entropy states (compared to random coil conformations) when crowded, with elongation states that are gamma distributed and fluctuate in time. However, the broadness of the distribution of states and the time-dependence and length scale of elongation length fluctuations depend on both DNA and crowder size with concentration having surprisingly little impact. Results collectively show that mobility reduction and coil elongation of large crowded DNAs are due to a complex interplay between entropic effects and crowder mobility. Although elongation and initial mobility retardation are driven by depletion interactions, subdiffusive dynamics, and the drastic exponential slowing of DNA, up to ∼300×, arise from the reduced mobility of larger crowders. Our results elucidate the highly important and widely debated effects of cellular crowding on genome-sized DNA. PMID:25762333

  5. A Dual-Targeting, p53-Independent, Apoptosis-Inducing Platinum(II) Anticancer Complex, [Pt(BDIQQ)]Cl

    PubMed Central

    Suntharalingam, Kogularamanan; Wilson, Justin J.; Lin, Wei; Lippard, Stephen J.

    2014-01-01

    The therapeutic index and cellular mechanism of action of [Pt(BDIQQ)]Cl, a monocationic, square-planar platinum(II) complex, are reported. [Pt(BDIQQ)]Cl was used to treat several cell lines, including wild type and cisplatin-resistant ovarian carcinoma cells (A2780 and A2780CP70) and non-proliferating lung carcinoma cells (A549). [Pt(BDIQQ)]Cl selectively kills cancer over healthy cells and exhibits no cross-resistance with cisplatin. The mechanism of cell killing was established through detailed cell-based assays. [Pt(BDIQQ)]Cl exhibits dual-threat capabilities, targeting nuclear DNA and mitochondria simultaneously. [Pt(BDIQQ)]Cl induces DNA damage, leading to p53 enrichment, mitochondrial membrane potential depolarisation, and caspase-mediated apoptosis. [Pt(BDIQQ)]Cl also accumulates in the mitochondria, resulting in direct mitochondrial damage. Flow cytometric studies demonstrated that [Pt(BDIQQ)]Cl has no significant effect on cell cycle progression. Remarkably, p53-status is a not a determinant of [Pt(BDIQQ)]Cl activity. In p53-null cells, [Pt(BDIQQ)]Cl induces cell death through mitochondrial dysfunction. Cancers with p53-null status could therefore be targeted using [Pt(BDIQQ)]Cl. PMID:24514456

  6. Inflammation induced NFATc1-STAT3 Transcription Complex Promotes Pancreatic Cancer initiation by KrasG12D

    PubMed Central

    Baumgart, Sandra; Chen, Nai-ming; Siveke, Jens T.; König, Alexander; Zhang, Jin-San; Singh, Shiv K.; Wolf, Elmar; Bartkuhn, Marek; Esposito, Irene; Heßmann, Elisabeth; Reinecke, Johanna; Nikorowitsch, Julius; Brunner, Marius; Singh, Garima; Fernandez-Zapico, Martin E.; Smyrk, Thomas; Bamlet, William R.; Eilers, Martin; Neesse, Albrecht; Gress, Thomas M.; Billadeau, Daniel D.; Tuveson, David; Urrutia, Raul; Ellenrieder, Volker

    2014-01-01

    Summary Cancer-associated inflammation is a molecular key feature in pancreatic ductal adenocarcinoma. Oncogenic KRAS in conjunction with persistent inflammation is known to accelerate carcinogenesis, although the underlying mechanisms remain poorly understood. Here we outline a novel pathway whereby the transcription factors NFATc1 and STAT3 cooperate in pancreatic epithelial cells to promote KrasG12D-driven carcinogenesis. NFATc1 activation is induced by inflammation and itself accelerates inflammation-induced carcinogenesis in KrasG12D mice, whereas genetic or pharmacological ablation of NFATc1 attenuates this effect. Mechanistically, NFATc1 complexes with STAT3 for enhancer-promoter communications at jointly regulated genes involved in oncogenesis, e.g. Cyclin, EGFR and WNT family members. The NFATc1-STAT3 cooperativity is operative in pancreatitis-mediated carcinogenesis as well as in established human pancreatic cancer. Together, these studies unravel new mechanisms of inflammatory driven pancreatic carcinogenesis and suggest beneficial effects of chemopreventive strategies using drugs which are currently available for targeting these factors in clinical trials. PMID:24694735

  7. A novel copper complex induces paraptosis in colon cancer cells via the activation of ER stress signalling.

    PubMed

    Gandin, Valentina; Pellei, Maura; Tisato, Francesco; Porchia, Marina; Santini, Carlo; Marzano, Cristina

    2012-01-01

    Platinum anticancer drugs have been used for three decades despite their serious side effects and the emerging of resistance phenomena. Recently, a phosphine copper(I) complex, [Cu(thp)(4)][PF(6)] (CP), gained special attention because of its strong antiproliferative effects. CP killed human colon cancer cells more efficiently than cisplatin and oxaliplatin and it overcame platinum drug resistance. CP preferentially reduced cancer cell viability whereas non-tumour cells were poorly affected. Colon cancer cells died via a programmed cell death whose transduction pathways were characterized by the absence of hallmarks of apoptosis. The inhibition of 26S proteasome activities induced by CP caused intracellular accumulation of polyubiquitinated proteins and the functional suppression of the ubiquitin-proteasome pathway thus triggering endoplasmic reticulum stress. These data, providing a mechanistic characterization of CP-induced cancer cell death, shed light on the signaling pathways involved in paraptosis thus offering a new tool to overcome apoptosis-resistance in colon cancer cells. PMID:21388518

  8. Phosphorylation of CREB at Ser-133 induces complex formation with CREB-binding protein via a direct mechanism.

    PubMed Central

    Parker, D; Ferreri, K; Nakajima, T; LaMorte, V J; Evans, R; Koerber, S C; Hoeger, C; Montminy, M R

    1996-01-01

    We have characterized a phosphoserine binding domain in the coactivator CREB-binding protein (CBP) which interacts with the protein kinase A-phosphorylated, and hence activated, form of the cyclic AMP-responsive factor CREB. The CREB binding domain, referred to as KIX, is alpha helical and binds to an unstructured kinase-inducible domain in CREB following phosphorylation of CREB at Ser-133. Phospho-Ser-133 forms direct contacts with residues in KIX, and these contacts are further stabilized by hydrophobic residues in the kinase-inducible domain which flank phospho-Ser-133. Like the src homology 2 (SH2) domains which bind phosphotyrosine-containing peptides, phosphoserine 133 appears to coordinate with a single arginine residue (Arg-600) in KIX which is conserved in the CBP-related protein P300. Since mutagenesis of Arg-600 to Gln severely reduces CREB-CBP complex formation, our results demonstrate that, as in the case of tyrosine kinase pathways, signal transduction through serine/threonine kinase pathways may also require protein interaction motifs which are capable of recognizing phosphorylated amino acids. PMID:8552098

  9. G1 phase arrest induced by Wilms tumor protein WT1 is abrogated by cyclin/CDK complexes.

    PubMed Central

    Kudoh, T; Ishidate, T; Moriyama, M; Toyoshima, K; Akiyama, T

    1995-01-01

    WT1, the Wilms tumor-suppressor gene, maps to the human chromosomal region 11p13 and encodes a transcriptional repressor, WT1, implicated in controlling normal urogenital development. Microinjection of the WT1 cDNA into quiescent cells or cells in early to mid G1 phase blocked serum-induced cell cycle progression into S phase. The activity of WT1 varied significantly depending on the presence or absence of an alternatively spliced region located upstream of the zinc finger domain. The inhibitory activity of WT1 was abrogated by the overexpression of cyclin E/CDK2 as well as cyclin D1/CDK4. Furthermore, both CDK4- and CDK2-associated kinase activities were downregulated in cells overexpressing WT1, whereas the levels of CDK4, CDK2, and cyclin D1 expression were unchanged. These findings suggest that inhibition of the activity of cyclin/CDK complexes may be involved in mediating the WT1-induced cell cycle block. Images Fig. 1 Fig. 2 PMID:7753836

  10. A novel high light-inducible carotenoid-binding protein complex in the thylakoid membranes of Synechocystis PCC 6803.

    PubMed

    Daddy, Soumana; Zhan, Jiao; Jantaro, Saowarath; He, Chenliu; He, Qingfang; Wang, Qiang

    2015-01-01

    Synechocystis sp. PCC 6803 is a model cyanobacterium extensively used to study photosynthesis. Here we reveal a novel high light-inducible carotenoid-binding protein complex (HLCC) in the thylakoid membranes of Synechocystis PCC 6803 cells exposed to high intensity light. Zeaxanthin and myxoxanthophyll accounted for 29.8% and 54.8%, respectively, of the carotenoids bound to the complex. Using Blue-Native PAGE followed by 2D SDS-PAGE and mass spectrometry, we showed that the HLCC consisted of Slr1128, IsiA, PsaD, and HliA/B. We confirmed these findings by SEAD fluorescence cross-linking and anti-PsaD immuno-coprecipitation analyses. The expression of genes encoding the protein components of the HLCC was enhanced by high light illumination and artificial oxidative stress. Deletion of these proteins resulted in impaired state transition and increased sensitivity to oxidative and/or high light stress, as indicated by increased membrane peroxidation. Therefore, the HLCC protects thylakoid membranes from extensive photooxidative damage, likely via a mechanism involving state transition. PMID:25820628

  11. A novel high light-inducible carotenoid-binding protein complex in the thylakoid membranes of Synechocystis PCC 6803

    PubMed Central

    Daddy, Soumana; Zhan, Jiao; Jantaro, Saowarath; He, Chenliu; He, Qingfang; Wang, Qiang

    2015-01-01

    Synechocystis sp. PCC 6803 is a model cyanobacterium extensively used to study photosynthesis. Here we reveal a novel high light-inducible carotenoid-binding protein complex (HLCC) in the thylakoid membranes of Synechocystis PCC 6803 cells exposed to high intensity light. Zeaxanthin and myxoxanthophyll accounted for 29.8% and 54.8%, respectively, of the carotenoids bound to the complex. Using Blue-Native PAGE followed by 2D SDS-PAGE and mass spectrometry, we showed that the HLCC consisted of Slr1128, IsiA, PsaD, and HliA/B. We confirmed these findings by SEAD fluorescence cross-linking and anti-PsaD immuno-coprecipitation analyses. The expression of genes encoding the protein components of the HLCC was enhanced by high light illumination and artificial oxidative stress. Deletion of these proteins resulted in impaired state transition and increased sensitivity to oxidative and/or high light stress, as indicated by increased membrane peroxidation. Therefore, the HLCC protects thylakoid membranes from extensive photooxidative damage, likely via a mechanism involving state transition. PMID:25820628

  12. Anti-apoptotic effect of San Huang Shel Shin Tang cyclodextrin complex (SHSSTc) on CCl4 -induced hepatotoxicity in rats.

    PubMed

    Yang, Cheng-Hsun; Ting, Wei-Jen; Shen, Chia-Yao; Hsu, Hsi-Hsien; Lin, Yueh-Min; Kuo, Chia-Hua; Tsai, Fuu-Jen; Tsai, Chang-Hai; Tsai, Yuhsin; Huang, Chih-Yang

    2016-06-01

    The metabolic loading is heavier in liver especially when injured or inflammation. San Huang Shel Shin Tang (SHSST) was an old traditional herbal decoction, which composed with Rheum officinale Baill, Scutellaria baicalnsis Geprgi and Coptis chinensis Franch (1:1:2 in weight), can provide a liver protection effects. We used a beta-cyclodextrin (β-CD) drug modification method in reduce of the necessary dose of the SHSST. As the results, the FAS-FADD expressions leaded apoptosis in CCl4 intraperitoneal (IP) injection induced acute liver injury in rats. Silymarin, baicalein, SHSST, and SHSST β-CD complex (SHSSTc) pretreatments protected liver through the decreasing of the expressions of FAS-FADD and downstream caspase-3 and caspase-8. Particularly, SHSSTc (30 mg/kg day) treatment enhanced cell survival pathway activation through the PI3K, Akt and Bad phosphorylation. Compared with SHSST as well as silymarin and baicalein, SHSSTc provided a magnificent liver protection effect, especially in survival pathway activation/TUNEL-apoptotic cell reduction/serum cholesterol level suppression. All these data suggested that β-CD complex modified the SHSST and promoted the bioavailability and liver protection effects. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 663-670, 2016. PMID:25447754

  13. Boronate Complex Formation with Dopa Containing Mussel Adhesive Protein Retards pH-Induced Oxidation and Enables Adhesion to Mica

    PubMed Central

    Israelachvili, Jacob N.; Chen, Yunfei; Waite, J. Herbert

    2014-01-01

    The biochemistry of mussel adhesion has inspired the design of surface primers, adhesives, coatings and gels for technological applications. These mussel-inspired systems often focus on incorporating the amino acid 3,4-dihydroxyphenyl-L-alanine (Dopa) or a catecholic analog into a polymer. Unfortunately, effective use of Dopa is compromised by its susceptibility to auto-oxidation at neutral pH. Oxidation can lead to loss of adhesive function and undesired covalent cross-linking. Mussel foot protein 5 (Mfp-5), which contains ∼30 mole % Dopa, is a superb adhesive under reducing conditions but becomes nonadhesive after pH-induced oxidation. Here we report that the bidentate complexation of borate by Dopa to form a catecholato-boronate can be exploited to retard oxidation. Although exposure of Mfp-5 to neutral pH typically oxidizes Dopa, resulting in a>95% decrease in adhesion, inclusion of borate retards oxidation at the same pH. Remarkably, this Dopa-boronate complex dissociates upon contact with mica to allow for a reversible Dopa-mediated adhesion. The borate protection strategy allows for Dopa redox stability and maintained adhesive function in an otherwise oxidizing environment. PMID:25303409

  14. Communication: Ultrafast time-resolved ion photofragmentation spectroscopy of photoionization-induced proton transfer in phenol-ammonia complex

    SciTech Connect

    Shen, Ching-Chi; Tsai, Tsung-Ting; Ho, Jr-Wei; Chen, Yi-Wei; Cheng, Po-Yuan

    2014-11-07

    Photoionization-induced proton transfer (PT) in phenol-ammonia (PhOH-NH{sub 3}) complex has been studied using ultrafast time-resolved ion photofragmentation spectroscopy. Neutral PhOH-NH{sub 3} complexes prepared in a free jet are photoionized by femtosecond [1+1] resonance-enhanced multiphoton ionization via the S{sub 1} state, and the subsequent dynamics occurring in the cations is probed by delayed pulses that result in ion fragmentation. The observed temporal evolutions of the photofragmentation spectra are consistent with an intracomplex PT reaction. The experiments revealed that PT in [PhOH-NH{sub 3}]{sup +} cation proceeds in two distinct steps: an initial impulsive wave-packet motion in ∼70 fs followed by a slower relaxation of about 1 ps that stabilizes the system into the final PT configuration. These results indicate that for a barrierless PT system, even though the initial PT motions are impulsive and ultrafast, the reaction may take a much longer time scale to complete.

  15. UV induced ubiquitination of the yeast Rad4-Rad23 complex promotes survival by regulating cellular dNTP pools.

    PubMed

    Zhou, Zheng; Humphryes, Neil; van Eijk, Patrick; Waters, Raymond; Yu, Shirong; Kraehenbuehl, Rolf; Hartsuiker, Edgar; Reed, Simon H

    2015-09-01

    Regulating gene expression programmes is a central facet of the DNA damage response. The Dun1 kinase protein controls expression of many DNA damage induced genes, including the ribonucleotide reductase genes, which regulate cellular dNTP pools. Using a combination of gene expression profiling and chromatin immunoprecipitation, we demonstrate that in the absence of DNA damage the yeast Rad4-Rad23 nucleotide excision repair complex binds to the promoters of certain DNA damage response genes including DUN1, inhibiting their expression. UV radiation promotes the loss of occupancy of the Rad4-Rad23 complex from the regulatory regions of these genes, enabling their induction and thereby controlling the production of dNTPs. We demonstrate that this regulatory mechanism, which is dependent on the ubiquitination of Rad4 by the GG-NER E3 ligase, promotes UV survival in yeast cells. These results support an unanticipated regulatory mechanism that integrates ubiquitination of NER DNA repair factors with the regulation of the transcriptional response controlling dNTP production and cellular survival after UV damage. PMID:26150418

  16. Photoswitchable stable charge-distributed states in a new cobalt complex exhibiting photo-induced valence tautomerism.

    PubMed

    Slota, Michael; Blankenhorn, Marian; Heintze, Eric; Vu, Minh; Hübner, Ralph; Bogani, Lapo

    2015-01-01

    We report the synthesis and magnetic and photomagnetic behaviour of a novel valence tautomeric cobalt complex, [Co(3,5-dbbq)2(μ-bpym)] (1) (3,5-dbbq = 3,5-di-tert-butyl-1,2-benzoquinone and μ-bpym = 2,2'-bipyrimidine). The synthesis is performed by reacting Co2(CO)8 and μ-bpym in the presence of the ligand 3,5-dbbq in a mixed solvent under inert atmosphere. The magnetic behavior clearly shows the presence of electron transfer from the catecholate ligand to the cobalt center, producing valence tautomers of [Co(II)(SQ)2] with a transition temperature (T1/2) of 215 K. Photomagnetic studies, performed via both SQUID magnetometry and X-band electron paramagnetic resonance, show the clear presence of photoinduced valence tautomerism, at temperatures considerably higher than previous systems. A metastable charge distribution is observed, strengthening previous investigations on the character of mixed valence ligands. Entropy-driven valence tautomeric interconversion is observed, and drives the transition to the most stable charge distribution. The complex has the ability to coordinate and can be used as a photoswitchable building block, with the photomagnetic characterisation evidencing a metastable state lifetime of the photo-induced valence tautomeric process of ca. 2.9 × 10(4) s below 20 K. The observed yields are higher than ones in similar systems, showing that tiny changes in the molecular structures may have a huge impact. PMID:26470791

  17. Regulation of hippocampal Fas receptor and death-inducing signaling complex after kainic acid treatment in mice.

    PubMed

    Keller, Benjamin; García-Sevilla, Jesús A

    2015-12-01

    Kainic acid (KA)-induced brain neuronal cell death (especially in the hippocampus) was shown to be mainly mediated by the intrinsic (mitochondrial) apoptotic pathway. This study investigated the regulation of the extrinsic apoptotic pathway mediated by Fas ligand/Fas receptor and components of the indispensable death-inducing signaling complex (DISC) in the hippocampus (marked changes) and cerebral cortex (modest changes) of KA-treated mice. KA (45mg/kg) induced a severe behavioral syndrome with recurrent motor seizures (scores; maximal at 60-90min; minimal at 72h) with activation of hippocampal pro-apoptotic JNK (+2.5 fold) and increased GFAP (+57%) and nuclear PARP-1 fragmentation (+114%) 72h post-treatment (delayed neurotoxicity). In the extrinsic apoptotic pathway (hippocampus), KA (72h) reduced Fas ligand (-92%) and Fas receptor aggregates (-24%). KA (72h) also altered the contents of major DISC components: decreased FADD adaptor (-44%), reduced activation of initiator caspase-8 (-47%) and increased survival FLIP-S (+220%). Notably, KA (72h) upregulated the content of anti-apoptotic p-Ser191 FADD (+41%) and consequently the expression of p-FADD/FADD ratio (+1.9-fold), a neuroplastic index. Moreover, the p-FADD dependent transcription factor NF-κB was also increased (+61%) in the hippocampus after KA (72h). The convergent adaptation of the extrinsic apoptotic machinery 72h after KA in mice (with otherwise normal gross behavior) is a novel finding which suggests the induction of survival mechanisms to partly counteract the delayed neuronal death in the hippocampus. PMID:26044520

  18. Structural analysis of ruthenium-arene complexes using ion mobility mass spectrometry, collision-induced dissociation, and DFT.

    PubMed

    Czerwinska, Izabella; Far, Johann; Kune, Christopher; Larriba-Andaluz, Carlos; Delaude, Lionel; De Pauw, Edwin

    2016-04-21

    Ion mobility mass spectrometry (IM-MS) and collision-induced dissociation (CID) techniques were used to investigate the influence of the phosphine ligand on the physicochemical properties of [RuCl2(p-cymene)(PCy3)] (), [RuCl2(p-cymene)(PPh3)] (), and [RuCl2(p-cymene)(PTA)] () in the gas phase (PTA is 1,3,5-triaza-7-phosphaadamantane). Electrospray ionization of complexes and led to the corresponding [RuCl(p-cymene)(PR3)](+) ions via the dissociation of a chlorido ligand, whereas RAPTA-C () afforded two molecular ions by in-source oxidation ([Ru(III)Cl2(p-cymene)(PTA)](+)) or protonation ([RuCl2(p-cymene)(PTA+H)](+)). Control experiments showed that the balance between these two ionization paths was strongly influenced by the nature of the solvent used for infusion. Collision cross sections (CCSs) of the four molecular ions accurately reflected the variations of steric bulk inferred from the Tolman steric parameters (θ) of the phosphine ligands. Moreover, DFT calculations combined with a model based on the kinetic theory of gases (the trajectory method of the IMoS software) afforded reliable CCS predictions. The almost two times higher dipole moment of [RuCl2(p-cymene)(PTA+H)](+) (μ = 13.75 D) compared to [Ru(III)Cl2(p-cymene)(PTA)](+) (μ = 7.18 D) was held responsible for increased ion-induced dipole interactions with a polarizable drift gas such as N2. Further experiments with He and CO2 confirmed that increasing the polarizability of the buffer gas improved the separation between the two molecular ions derived from complex . The fragmentation patterns of complexes were determined by CID. The sequence of collision voltages at which 50% of a precursor ion dissociates (V50) recorded for the molecular ions derived from compounds was in good agreement with simple electronic considerations based on the donor strength of the phosphine ligand. Thus, the CCS and V50 parameters used to determine the shape and stability of ionic species in the gas phase are complementary

  19. Inhibition of InhA activity, but not KasA activity, induces formation of a KasA-containing complex in mycobacteria.

    PubMed

    Kremer, Laurent; Dover, Lynn G; Morbidoni, Hector R; Vilchèze, Catherine; Maughan, William N; Baulard, Alain; Tu, Shiao-Chun; Honoré, Nadine; Deretic, Vojo; Sacchettini, James C; Locht, Camille; Jacobs, William R; Besra, Gurdyal S

    2003-06-01

    Isoniazid (INH) remains one of the key drugs used to control tuberculosis, with the enoyl-AcpM reductase InhA being the primary target. However, based on the observation that INH-treated Mycobacterium tuberculosis overproduces KasA, an enzyme involved in the biosynthesis of mycolic acids, and induces the formation of a covalent complex consisting of AcpM, KasA, and INH, it has been proposed that KasA represents the primary target of INH. However, the relevance of this complex to INH action remains obscure. This study was aimed at clarifying the role of InhA and KasA in relation to INH activity. By using anti-KasA antibodies we detected the KasA-containing complex in INH-treated Mycobacterium smegmatis. In addition, INH-treated cells also produced constant levels of KasA that were not sequestered in the complex and presumably were sufficient to ensure mycolic acid biosynthesis. Interestingly, a furA-lacking strain induced the complex at lower concentrations of INH compared with the control strain, whereas higher INH concentrations were necessary to induce the complex in a strain that lacks katG, suggesting that INH needs to be activated by KatG to induce the KasA-containing complex. The InhA inhibitors ethionamide and diazaborine also induced the complex; thus, its formation was not specifically relevant to INH action but was because of InhA inhibition. In addition, in vitro assays using purified InhA and KasA demonstrated that KatG-activated INH, triclosan, and diazaborine inhibited InhA but not KasA activity. Moreover, several thermosensitive InhA mutant strains of M. smegmatis constitutively expressed the KasA-containing complex. This study provides the biochemical and genetic evidence. 1) Only inhibition of InhA, but not KasA, induces the KasA-containing complex. 2) INH is not part of the complex. 3) INH does not target KasA, consistent with InhA being the primary target of INH. PMID:12654922

  20. Letter: Electron-capture dissociation and collision-induced dissociation fragmentation of the supermetallized complexes of Substance P with potassium, cesium and silver.

    PubMed

    Kostyukevich, Yury; Zherebker, Alexander; Kononikhin, Alexey; Indeykina, Maria; Popov, Igor; Nikolaev, Eugene

    2016-01-01

    We report the investigation of the collision-induced dissociation (CID) and electron-capture dissociation (ECD) product fragmentations of the supermetallized complexes of Substance P and several monovalent metals. The supermetallization is the phenomenon of the formation of the complex ion peptide-metals in the gas phase when the peptide accepts an unexpectedly large number of metals. We have obtained and investigated complexes with the incorporation of up to four cesium (Cs), up to five potassium (K) and up to six silver (Ag) atoms. The current research reveals crucial changes in the complex behavior in the cases of different metals. It was observed that in CID spectra of complexes with Cs and K is dominated by the peak corresponding to the loss of metal cation while ECD gives a rich fragmentation. In the case of complexes with Ag, the loss of Ag(+) occurs in ECD while the CID shows a good fragmentation. PMID:27419902

  1. Hydroxychloroquine protects melanocytes from autoantibody-induced injury by reducing the binding of antigen-antibody complexes.

    PubMed

    Li, Dong-Guang; Hu, Wen-Zhi; Ma, Hui-Jun; Liu, Wen; Yang, Qing-Qi; Zhao, Guang

    2016-08-01

    Vitiligo is a polygenic autoimmune disorder characterized by loss of pigmentation due to melanocyte destruction. Hydroxychloroquine (HCQ) is an effective immunosuppressant widely used in the treatment of autoimmune disorders. As generalized vitiligo (GV) is commonly considered to be a T cell and autoantibody-induced immune disorder, the present study aimed to determine whether HCQ protects melanocytes from autoantibody‑induced disruption. Anti‑melanocyte antibodies were obtained from the serum of patients with progressive GV and the effects of HCQ on prevent the autoantibody‑induced disruption of melanocytes was observed. Cell‑based ELISA, indirect immunofluorescence and western blotting were used to analyze the autoantibody content of sera samples obtained from 32 patients with progressive GV. The cytotoxicity of HCQ was detected by MTT assay, and 1 µg/ml HCQ was applied to human primary melanocytes (HMCs) to examine whether it could exert protective effects against autoantibody‑induced immune injury. Flow cytometry was used to measure autoantibody binding to the surface of HMCs. Complement‑dependent cytotoxicity (CDC) and antibody‑dependent cell‑mediated cytotoxicity (ADCC) were monitored by MTT and lactate dehydrogenase‑releasing assays. The concentration of autoantibodies in sera samples taken from GV patients was significantly higher than in controls, particularly in patients who had >10% of their body surface affected by vitiligo. The majority of the autoantibodies presented in the HMCs and human keratinocytes (HKCs) and were predominantly localized to the cell surface and cytoplasm. The molecular weights of the autoantigens were identified as 30, 37‑39, 42, 53, 60‑75, 90, 100, 110, and 126 kDa; the 30 kDa protein was observed only in HMCs. The addition of HCQ at a concentration of 1 µg/ml produced no significant cytotoxicity in HMCs and was demonstrated to reduce the binding of GV immunoglobulin G (IgG) to the surface of HMCs

  2. Dissociation of MIF-rpS3 complex and sequential NF-κB activation is involved in IR-induced metastatic conversion of NSCLC.

    PubMed

    Youn, HyeSook; Son, Beomseok; Kim, Wanyeon; Jun, Se Young; Lee, Jung Sub; Lee, Jae-Myung; Kang, ChulHee; Kim, Joon; Youn, BuHyun

    2015-11-01

    Frequent relapse and spreading of tumors during radiotherapy are principal obstacles to treatment of non-small cell lung cancer (NSCLC). In this study, we aimed to investigate how macrophage migration inhibitory factor (MIF) which is expressed at high levels in metastatic and primary lung cancer cells could regulate NSCLC metastasis in response to ionizing radiation (IR). The results indicated that MIF and ribosomal protein S3 (rpS3) were shown to be connected to inflammation, proliferation, and metastasis of NSCLC via IR-induced activation of the NF-κB pathway. Under unirradiated conditions, MIF physically established a complex with rpS3. MIF-rpS3 dissociation induced by IR activated NF-κB and made the expression of target genes of this factor transactivated in two NSCLC cell lines, A549, and NCI-H358. We also found that IR-induced dissociation of this complex led to increased secretion of pro-inflammatory cytokines and modulated the expression of epithelial-mesenchymal transition marker proteins. Finally, the effects of IR-induced dissociation of the MIF-rpS3 complex on tumor metastasis were confirmed by in vivo xenograft studies. Taken together, the present study revealed that dissociation of the MIF-rpS3 complex and subsequent activation of NF-κB is a critical post-IR exposure event that accounts for IR-induced metastatic conversion of NSCLC. PMID:25900216

  3. Complete Mitochondrial Complex I Deficiency Induces an Up-Regulation of Respiratory Fluxes That Is Abolished by Traces of Functional Complex I.

    PubMed

    Kühn, Kristina; Obata, Toshihiro; Feher, Kristen; Bock, Ralph; Fernie, Alisdair R; Meyer, Etienne H

    2015-08-01

    Complex I (NADH:ubiquinone oxidoreductase) is central to cellular NAD(+) recycling and accounts for approximately 40% of mitochondrial ATP production. To understand how complex I function impacts respiration and plant development, we isolated Arabidopsis (Arabidopsis thaliana) lines that lack complex I activity due to the absence of the catalytic subunit NDUFV1 (for NADH:ubiquinone oxidoreductase flavoprotein1) and compared these plants with ndufs4 (for NADH:ubiquinone oxidoreductase Fe-S protein4) mutants possessing trace amounts of complex I. Unlike ndufs4 plants, ndufv1 lines were largely unable to establish seedlings in the absence of externally supplied sucrose. Measurements of mitochondrial respiration and ATP synthesis revealed that compared with ndufv1, the complex I amounts retained by ndufs4 did not increase mitochondrial respiration and oxidative phosphorylation capacities. No major differences were seen in the mitochondrial proteomes, cellular metabolomes, or transcriptomes between ndufv1 and ndufs4. The analysis of fluxes through the respiratory pathway revealed that in ndufv1, fluxes through glycolysis and the tricarboxylic acid cycle were dramatically increased compared with ndufs4, which showed near wild-type-like fluxes. This indicates that the strong growth defects seen for plants lacking complex I originate from a switch in the metabolic mode of mitochondria and an up-regulation of respiratory fluxes. Partial reversion of these phenotypes when traces of active complex I are present suggests that complex I is essential for plant development and likely acts as a negative regulator of respiratory fluxes. PMID:26134164

  4. Complete Mitochondrial Complex I Deficiency Induces an Up-Regulation of Respiratory Fluxes That Is Abolished by Traces of Functional Complex I1[OPEN

    PubMed Central

    Kühn, Kristina; Obata, Toshihiro; Feher, Kristen; Bock, Ralph; Fernie, Alisdair R.; Meyer, Etienne H.

    2015-01-01

    Complex I (NADH:ubiquinone oxidoreductase) is central to cellular NAD+ recycling and accounts for approximately 40% of mitochondrial ATP production. To understand how complex I function impacts respiration and plant development, we isolated Arabidopsis (Arabidopsis thaliana) lines that lack complex I activity due to the absence of the catalytic subunit NDUFV1 (for NADH:ubiquinone oxidoreductase flavoprotein1) and compared these plants with ndufs4 (for NADH:ubiquinone oxidoreductase Fe-S protein4) mutants possessing trace amounts of complex I. Unlike ndufs4 plants, ndufv1 lines were largely unable to establish seedlings in the absence of externally supplied sucrose. Measurements of mitochondrial respiration and ATP synthesis revealed that compared with ndufv1, the complex I amounts retained by ndufs4 did not increase mitochondrial respiration and oxidative phosphorylation capacities. No major differences were seen in the mitochondrial proteomes, cellular metabolomes, or transcriptomes between ndufv1 and ndufs4. The analysis of fluxes through the respiratory pathway revealed that in ndufv1, fluxes through glycolysis and the tricarboxylic acid cycle were dramatically increased compared with ndufs4, which showed near wild-type-like fluxes. This indicates that the strong growth defects seen for plants lacking complex I originate from a switch in the metabolic mode of mitochondria and an up-regulation of respiratory fluxes. Partial reversion of these phenotypes when traces of active complex I are present suggests that complex I is essential for plant development and likely acts as a negative regulator of respiratory fluxes. PMID:26134164

  5. Light-induced voltage changes associated with electron and proton transfer in photosystem II core complexes reconstituted in phospholipid monolayers.

    PubMed Central

    Höök, F; Brzezinski, P

    1994-01-01

    We have measured light-induced voltage changes (electrogenic events) in photosystem II (PSII) core complexes oriented in phospholipid monolayers. These events are compared to those measured in the functionally and structurally closely related reaction centers from the photosynthetic bacterium Rhodobacter sphaeroides. In both systems we observed a rapid (< 100 ns) light-induced increase in voltage associated with charge separation. In PSII reaction centers it was followed by a decrease (decay) of approximately 14% of the charge-separation voltage and a time constant of approximately 500 microseconds. In bacterial reaction centers this decay was approximately 9% of the charge-separation voltage, and the time constant was approximately 200 microseconds. The decay was presumably associated with a structural change. In bacterial reaction centers, in the presence of excess water-soluble cytochrome c2+, it was followed by a slower increase of approximately 30% of the charge-separation voltage, associated with electron transfer from the cytochrome to the oxidized donor, P+. In PSII reaction centers, after the decay the voltage remained on the same level for > or = 0.5 s. In PSII reaction centers the electron transfer Q-AQB-->QA Q-B contributed with an electrogenicity of < or = 5% of that of the charge separation. In bacterial reaction centers this electrogenicity was < or = 2% of the charge-separation electrogenicity. Proton transfer to Q2-B in PSII reaction centers contributed with approximately 5% of the charge-separation voltage, which is approximately a factor of three smaller than that observed in bacterial reaction centers. PMID:8075340

  6. Distinctive western blot antibody patterns induced by infection of mice with individual strains of the Mycobacterium avium complex.

    PubMed Central

    Elsaghier, A; Nolan, A; Allen, B; Ivanyi, J

    1992-01-01

    Systemic infection of mice with organisms of the Mycobacterium avium complex (MAC) induced antibody responses, characteristic for each of the three tested individual strains. The influence of host genetic factors was reflected up to 3 months after infection by the finding of generally oligobanded and multibanded Western blot patterns in C57B1/6 and BALB/c mice, respectively. Nevertheless, more bands developed at 6 months in C57BL/6 mice. The response to three antigens of 18,000, 38,000 and 24,000 MW was analysed in greater detail. Antibodies to a protease-resistant 18,000 MW band produced only by BALB/c mice were either strain specific, following infection with M. avium, strain Maa-B2, or cross-reactive within MAC, following infection with M. avium strain Maa-A6 and M. paratuberculosis, strain Map-203. Another protease-resistant antigen of 38,000 MW was immunogenic only in Maa-B2 infected mice. This constituent was found to be related to the protease-sensitive antigen of corresponding molecular weight from M. tuberculosis. Two 24,000 MW proteins of M. paratuberculosis were separated by two-dimensional gel electrophoresis: antibodies to the anodic band were induced by Map-203 infection, whilst the cathodic band was revealed by heteroclitic antibodies from Maa-B2-infected mice. The latter antigen is apparently expressed during in vivo replication, but not during in vitro culture of Maa-B2 bacteria. We generally conclude, that the selective antibody patterns after live infection, could be attributed to differences in the release of native antigens within mycobacterial lesions. In view of a high degree of species specificity, some of the immunogenic constituents identified may also be useful for serodiagnostic application. Images Figure 2 Figure 3 Figure 4 Figure 5 PMID:1526646

  7. Three-Dimensional Analysis of a Viral RNA Replication Complex Reveals a Virus-Induced Mini-Organelle

    PubMed Central

    Kopek, Benjamin G; Perkins, Guy; Miller, David J; Ellisman, Mark H; Ahlquist, Paul

    2007-01-01

    Positive-strand RNA viruses are the largest genetic class of viruses and include many serious human pathogens. All positive-strand RNA viruses replicate their genomes in association with intracellular membrane rearrangements such as single- or double-membrane vesicles. However, the exact sites of RNA synthesis and crucial topological relationships between relevant membranes, vesicle interiors, surrounding lumens, and cytoplasm generally are poorly defined. We applied electron microscope tomography and complementary approaches to flock house virus (FHV)–infected Drosophila cells to provide the first 3-D analysis of such replication complexes. The sole FHV RNA replication factor, protein A, and FHV-specific 5-bromouridine 5'-triphosphate incorporation localized between inner and outer mitochondrial membranes inside ∼50-nm vesicles (spherules), which thus are FHV-induced compartments for viral RNA synthesis. All such FHV spherules were outer mitochondrial membrane invaginations with interiors connected to the cytoplasm by a necked channel of ∼10-nm diameter, which is sufficient for ribonucleotide import and product RNA export. Tomographic, biochemical, and other results imply that FHV spherules contain, on average, three RNA replication intermediates and an interior shell of ∼100 membrane-spanning, self-interacting protein As. The results identify spherules as the site of protein A and nascent RNA accumulation and define spherule topology, dimensions, and stoichiometry to reveal the nature and many details of the organization and function of the FHV RNA replication complex. The resulting insights appear relevant to many other positive-strand RNA viruses and support recently proposed structural and likely evolutionary parallels with retrovirus and double-stranded RNA virus virions. PMID:17696647

  8. The complex interplay of iron metabolism, reactive oxygen species, and reactive nitrogen species: insights into the potential of various iron therapies to induce oxidative and nitrosative stress.

    PubMed

    Koskenkorva-Frank, Taija S; Weiss, Günter; Koppenol, Willem H; Burckhardt, Susanna

    2013-12-01

    Production of minute concentrations of superoxide (O2(*-)) and nitrogen monoxide (nitric oxide, NO*) plays important roles in several aspects of cellular signaling and metabolic regulation. However, in an inflammatory environment, the concentrations of these radicals can drastically increase and the antioxidant defenses may become overwhelmed. Thus, biological damage may occur owing to redox imbalance-a condition called oxidative and/or nitrosative stress. A complex interplay exists between iron metabolism, O2(*-), hydrogen peroxide (H2O2), and NO*. Iron is involved in both the formation and the scavenging of these species. Iron deficiency (anemia) (ID(A)) is associated with oxidative stress, but its role in the induction of nitrosative stress is largely unclear. Moreover, oral as well as intravenous (iv) iron preparations used for the treatment of ID(A) may also induce oxidative and/or nitrosative stress. Oral administration of ferrous salts may lead to high transferrin saturation levels and, thus, formation of non-transferrin-bound iron, a potentially toxic form of iron with a propensity to induce oxidative stress. One of the factors that determine the likelihood of oxidative and nitrosative stress induced upon administration of an iv iron complex is the amount of labile (or weakly-bound) iron present in the complex. Stable dextran-based iron complexes used for iv therapy, although they contain only negligible amounts of labile iron, can induce oxidative and/or nitrosative stress through so far unknown mechanisms. In this review, after summarizing the main features of iron metabolism and its complex interplay with O2(*-), H2O2, NO*, and other more reactive compounds derived from these species, the potential of various iron therapies to induce oxidative and nitrosative stress is discussed and possible underlying mechanisms are proposed. Understanding the mechanisms, by which various iron formulations may induce oxidative and nitrosative stress, will help us

  9. Ion Mobility-Mass Spectrometry Reveals Highly-Compact Intermediates in the Collision Induced Dissociation of Charge-Reduced Protein Complexes

    NASA Astrophysics Data System (ADS)

    Bornschein, Russell E.; Niu, Shuai; Eschweiler, Joseph; Ruotolo, Brandon T.

    2016-01-01

    Protocols that aim to construct complete models of multiprotein complexes based on ion mobility and mass spectrometry data are becoming an important element of integrative structural biology efforts. However, the usefulness of such data is predicated, in part, on an ability to measure individual subunits removed from the complex while maintaining a compact/folded state. Gas-phase dissociation of intact complexes using collision induced dissociation is a potentially promising pathway for acquiring such protein monomer size information, but most product ions produced are possessed of high charge states and elongated/string-like conformations that are not useful in protein complex modeling. It has previously been demonstrated that the collision induced dissociation of charge-reduced protein complexes can produce compact subunit product ions; however, their formation mechanism is not well understood. Here, we present new experimental evidence for the avidin (64 kDa) and aldolase (157 kDa) tetramers that demonstrates significant complex remodeling during the dissociation of charge-reduced assemblies. Detailed analysis and modeling indicates that highly compact intermediates are accessed during the dissociation process by both complexes. Here, we present putative pathways that describe the formation of such ions, as well as discuss the broader significance of such data for structural biology applications moving forward.

  10. Clioquinol and pyrrolidine dithiocarbamate complex with copper to form proteasome inhibitors and apoptosis inducers in human breast cancer cells

    PubMed Central

    Daniel, Kenyon G; Chen, Di; Orlu, Shirley; Cui, Qiuzhi Cindy; Miller, Fred R; Dou, Q Ping

    2005-01-01

    Introduction A physiological feature of many tumor tissues and cells is the tendency to accumulate high concentrations of copper. While the precise role of copper in tumors is cryptic, copper, but not other trace metals, is required for angiogenesis. We have recently reported that organic copper-containing compounds, including 8-hydroxyquinoline-copper(II) and 5,7-dichloro-8-hydroxyquinoline-copper(II), comprise a novel class of proteasome inhibitors and tumor cell apoptosis inducers. In the current study, we investigate whether clioquinol (CQ), an analog of 8-hydroxyquinoline and an Alzheimer's disease drug, and pyrrolidine dithiocarbamate (PDTC), a known copper-binding compound and antioxidant, can interact with copper to form cancer-specific proteasome inhibitors and apoptosis inducers in human breast cancer cells. Tetrathiomolybdate (TM), a strong copper chelator currently being tested in clinical trials, is used as a comparison. Methods Breast cell lines, normal, immortalized MCF-10A, premalignant MCF10AT1K.cl2, and malignant MCF10DCIS.com and MDA-MB-231, were treated with CQ or PDTC with or without prior interaction with copper, followed by measurement of proteasome inhibition and cell death. Inhibition of the proteasome was determined by levels of the proteasomal chymotrypsin-like activity and ubiquitinated proteins in protein extracts of the treated cells. Apoptotic cell death was measured by morphological changes, Hoechst staining, and poly(ADP-ribose) polymerase cleavage. Results When in complex with copper, both CQ and PDTC, but not TM, can inhibit the proteasome chymotrypsin-like activity, block proliferation, and induce apoptotic cell death preferentially in breast cancer cells, less in premalignant breast cells, but are non-toxic to normal/non-transformed breast cells at the concentrations tested. In contrast, CQ, PDTC, TM or copper alone had no effects on any of the cells. Breast premalignant or cancer cells that contain copper at concentrations

  11. Resonant alteration of propagation in guiding structures with complex Robin parameter and its magnetic-field-induced restoration

    SciTech Connect

    Olendski, O.

    2011-06-15

    Highlights: > Solutions of the wave equation are analyzed for the confined circular geometry with complex Robin boundary conditions. > Sharp extremum is found in the energy dependence on the imaginary part of the extrapolation length. > Nonzero real part of the Robin length or/and magnetic field wipe out the resonance. - Abstract: Solutions of the scalar Helmholtz wave equation are derived for the analysis of the transport and thermodynamic properties of the two-dimensional disk and three-dimensional infinitely long straight wire in the external uniform longitudinal magnetic field B under the assumption that the Robin boundary condition contains extrapolation length {Lambda} with nonzero imaginary part {Lambda}{sub i}. As a result of this complexity, the self-adjointness of the Hamiltonian is lost, its eigenvalues E become complex too and the discrete bound states of the disk characteristic for the real {Lambda} turn into the corresponding quasibound states with their lifetime defined by the eigenenergies imaginary parts E{sub i}. Accordingly, the longitudinal flux undergoes an alteration as it flows along the wire with its attenuation/amplification being E{sub i}-dependent too. It is shown that, for zero magnetic field, the component E{sub i} as a function of the Robin imaginary part exhibits a pronounced sharp extremum with its magnitude being the largest for the zero real part {Lambda}{sub r} of the extrapolation length. Increasing magnitude of {Lambda}{sub r} quenches the E{sub i} - {Lambda}{sub i} resonance and at very large {Lambda}{sub r} the eigenenergies E approach the asymptotic real values independent of {Lambda}{sub i}. The extremum is also wiped out by the magnetic field when, for the large B, the energies tend to the Landau levels. Mathematical and physical interpretations of the obtained results are provided; in particular, it is shown that the finite lifetime of the disk quasibound states stems from the {Lambda}{sub i}-induced currents flowing

  12. Thermal and near-infrared light induced spin crossover in a mononuclear iron(ii) complex with a tetrathiafulvalene-fused dipyridophenazine ligand.

    PubMed

    Pointillart, F; Liu, X; Kepenekian, M; Le Guennic, B; Golhen, S; Dorcet, V; Roisnel, T; Cador, O; You, Z; Hauser, J; Decurtins, S; Ouahab, L; Liu, S-X

    2016-07-28

    A mononuclear Fe(ii) complex involving a tetrathiafulvalene-based ligand exhibits thermal spin-crossover (around 143 K) with pronounced hysteresis behaviour (48 K). The chromophoric and π-extended ligand allows Near-Infrared (NIR) sensitization for the light-induced excited spin-state trapping (LIESST) with T(LIESST) = 90 K. PMID:27358063

  13. Regioselective Lithium-Iodine Exchange-Initiated Cleavage of 2-Iodomethyl-1,3-dioxanes: A Complex-Induced Proximity Effect.

    PubMed

    Bailey, William F; Fair, Justin D

    2016-05-01

    Lithium-iodine exchange-initiated fragmentation of a series of 4-substituted 2-iodomethyl-1,3-dioxanes proceeds rapidly and regioselectively to afford enol ether alcohols by preferential cleavage of the less congested C(2)-O(1) bond. The results demonstrate that a complex-induced proximity effect (CIPE) is likely responsible for the selectivity of the cleavage. PMID:27074433

  14. Tetrathiomolybdate inhibits mitochondrial complex IV and mediates degradation of hypoxia-inducible factor-1α in cancer cells

    PubMed Central

    Kwang Kim, Kyu; Abelman, Sarah; Yano, Naohiro; Ribeiro, Jennifer R.; Singh, Rakesh K.; Tipping, Marla; Moore, Richard G.

    2015-01-01

    Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that triggers adaptive responses upon low oxygen conditions and plays a crucial role in cancer metabolism and therapy resistance. Tetrathiomolybdate (TM), a therapy option for copper overload disorder, has also been shown to be capable of limiting tumor angiogenesis, although its underlying mechanism remains unclear. Using ovarian and endometrial cancer cell lines, we observed that TM downregulates HIF-1α protein levels and HIF-transcriptional targets involved in tumor angiogenesis and glycolysis, but did not affect HIF-1α protein synthesis. TM-mediated HIF-1α downregulation was suppressed when HIF-prolyl hydroxylase activity was pharmacologically inhibited using deferoxamine or dimethyloxaloylglycine, and also when the oxygen-dependent degradation domains of HIF-1α, which are responsible for the interaction with HIF-prolyl hydroxylase, were deleted. These findings suggest that TM causes HIF-1α downregulation in a HIF-prolyl hydroxylase-dependent manner. Our studies showed that TM inhibits the activity of the copper-dependent mitochondrial complex IV and reduces mitochondrial respiration, thereby possibly increasing oxygen availability, which is crucial for HIF-prolyl hydroxylase activity. Pimonidazole staining also showed that TM elevates oxygen tension in hypoxic cells. Our studies provide mechanistic evidence for TM-mediated HIF-1α regulation and suggest its therapeutic potential as a method of blocking angiogenesis in ovarian and endometrial tumors. PMID:26469226

  15. Single platelets seal neutrophil-induced vascular breaches via GPVI during immune-complex-mediated inflammation in mice.

    PubMed

    Gros, Angèle; Syvannarath, Varouna; Lamrani, Lamia; Ollivier, Véronique; Loyau, Stéphane; Goerge, Tobias; Nieswandt, Bernhard; Jandrot-Perrus, Martine; Ho-Tin-Noé, Benoît

    2015-08-20

    Platelets protect vascular integrity during inflammation. Recent evidence suggests that this action is independent of thrombus formation and requires the engagement of glycoprotein VI (GPVI), but it remains unclear how platelets prevent inflammatory bleeding. We investigated whether platelets and GPVI act primarily by preventing detrimental effects of neutrophils using models of immune complex (IC)-mediated inflammation in mice immunodepleted in platelets and/or neutrophils or deficient in GPVI. Depletion of neutrophils prevented bleeding in thrombocytopenic and GPVI(-/-) mice during IC-mediated dermatitis. GPVI deficiency did not modify neutrophil recruitment, which was reduced by thrombocytopenia. Neutrophil cytotoxic activities were reduced in thrombocytopenic and GPVI(-/-) mice during IC-mediated inflammation. Intravital microscopy revealed that in this setting, intravascular binding sites for platelets were exposed by neutrophils, and GPVI supported the recruitment of individual platelets to these spots. Furthermore, the platelet secretory response accompanying IC-mediated inflammation was partly mediated by GPVI, and blocking of GPVI signaling impaired the vasculoprotective action of platelets. Together, our results show that GPVI plays a dual role in inflammation by enhancing neutrophil-damaging activities while supporting the activation and hemostatic adhesion of single platelets to neutrophil-induced vascular breaches. PMID:26036804

  16. Pathogenicity of Bovine Neonatal Pancytopenia-associated vaccine-induced alloantibodies correlates with Major Histocompatibility Complex class I expression

    PubMed Central

    Benedictus, Lindert; Luteijn, Rutger D.; Otten, Henny; Jan Lebbink, Robert; van Kooten, Peter J. S.; Wiertz, Emmanuel J. H. J.; Rutten, Victor P. M. G.; Koets, Ad P.

    2015-01-01

    Bovine Neonatal Pancytopenia (BNP), a fatal bleeding syndrome of neonatal calves, is caused by maternal alloantibodies absorbed from colostrum and is characterized by lymphocytopenia, thrombocytopenia and bone marrow hypoplasia. An inactivated viral vaccine is the likely source of alloantigens inducing BNP-associated alloantibodies in the dam. In this study the specificity of BNP alloantibodies was assessed and was linked to the pathology of BNP. We demonstrated that Major Histocompatibility Complex class I (MHC I) and Very Late Antigen-3, an integrin α3/β1 heterodimer, were the major targets of BNP alloantibodies. However, alloantibody binding to various bovine cell types correlated with MHC I expression, rather than integrin β1 or α3 expression. Likewise, alloantibody-dependent complement-mediated cell lysis correlated strongly with MHC I expression. Examination of several tissues of third trimester bovine foetuses revealed that cells, shown to be affected in calves with BNP, were characterized by high MHC class I expression and high levels of alloantibody binding. We conclude that in spite of the heterogeneous specificity of BNP associated maternal alloantibodies, MHC I-specific antibodies mediate the pathogenicity of BNP in the calf and that cells with high MHC I expression were preferentially affected in BNP. PMID:26235972

  17. Tetrapositive plutonium, neptunium, uranium, and thorium coordination complexes: chemistry revealed by electron transfer and collision induced dissociation.

    PubMed

    Gong, Yu; Tian, Guoxin; Rao, Linfeng; Gibson, John K

    2014-04-17

    The Pu(4+), Np(4+), and U(4+) ions, which have large electron affinities of ∼34.6, ∼33.6, and ∼32.6 eV, respectively, were stabilized from solution to the gas phase upon coordination by three neutral tetramethyl-3-oxa-glutaramide ligands (TMOGA). Both collision induced dissociation (CID) and electron transfer dissociation (ETD) of Pu(TMOGA)3(4+) reveal the propensity for reduction of Pu(IV) to Pu(III), by loss of TMOGA(+) in CID and by simple electron transfer in ETD. The reduction of Pu(IV) is in distinct contrast to retention of Th(IV) in both CID and ETD of Th(TMOGA)3(4+), where only the C-Oether bond cleavage product was observed. U(TMOGA)3(4+) behaves similarly to Th(TMOGA)3(4+) upon CID and ETD, while the fragmentation patterns of Np(TMOGA)3(4+) lie between those of Pu(TMOGA)3(4+) and U(TMOGA)3(4+). It is notable that the gas-phase fragmentation behaviors of these exceptional tetrapositive complexes parallel fundamental differences in condensed phase chemistry within the actinide series, specifically the tendency for reduction from the IV to III oxidation states. PMID:24660979

  18. Light-harvesting complexes in photosystem II regulate glutathione-induced sensitivity of Arabidopsis guard cells to abscisic acid.

    PubMed

    Jahan, Md Sarwar; Nozulaidi, Mohd; Khairi, Mohd; Mat, Nashriyah

    2016-05-20

    Light-harvesting complexes (LHCs) in photosystem II (PSII) regulate glutathione (GSH) functions in plants. To investigate whether LHCs control GSH biosynthesis that modifies guard cell abscisic acid (ABA) sensitivity, we evaluated GSH content, stomatal aperture, reactive oxygen species (ROS), weight loss and plant growth using a ch1-1 mutant that was defective of LHCs and compared this with wild-type (WT) Arabidopsis thaliana plants. Glutathione monoethyl ester (GSHmee) increased but 1-chloro-2,4 dinitrobenzene (CDNB) decreased the GSH content in the guard cells. The guard cells of the ch1-1 mutants accumulated significantly less GSH than the WT plants. The guard cells of the ch1-1 mutants also showed higher sensitivity to ABA than the WT plants. The CDNB treatment increased but the GSHmee treatment decreased the ABA sensitivity of the guard cells without affecting ABA-induced ROS production. Dark and light treatments altered the GSH content and stomatal aperture of the guard cells of ch1-1 and WT plants, irrespective of CDNB and GSHmee. The ch1-1 mutant contained fewer guard cells and displayed poor growth, late flowering and stumpy weight loss compared with the WT plants. This study suggests that defective LHCs reduced the GSH content in the guard cells and increased sensitivity to ABA, resulting in stomatal closure. PMID:26970687

  19. Mycobacterium tuberculosis PE25/PPE41 protein complex induces activation and maturation of dendritic cells and drives Th2-biased immune responses.

    PubMed

    Chen, Wei; Bao, Yige; Chen, Xuerong; Burton, Jeremy; Gong, Xueli; Gu, Dongqing; Mi, Youjun; Bao, Lang

    2016-04-01

    Mycobacterium tuberculosis evades innate host immune responses by parasitizing macrophages and causes significant morbidity and mortality around the world. A mycobacterial antigen that can activate dendritic cells (DCs) and elicit effective host innate immune responses will be vital to the development of an effective TB vaccine. The M. tuberculosis genes PE25/PPE41 encode proteins which have been associated with evasion of the host immune response. We constructed a PE25/PPE41 complex gene via splicing by overlapping extension and expressed it successfully in E. coli. We investigated whether this protein complex could interact with DCs to induce effective host immune responses. The PE25/PPE41 protein complex induced maturation of isolated mouse DCs in vitro, increasing expression of cell surface markers (CD80, CD86 and MHC-II), thereby promoting Th2 polarization via secretion of pro-inflammatory cytokines IL-4 and IL-10. In addition, PE25/PPE41 protein complex-activated DCs induced proliferation of mouse CD4(+) and CD8(+) T cells, and a strong humoral response in immunized mice. The sera of five TB patients were also highly reactive to this antigen. These findings suggest that interaction of the PE25/PPE41 protein complex with DCs may be of great immunological significance. PMID:26318856

  20. Dectin-1 targeting delivery of TNF-α antisense ODNs complexed with β-1,3-glucan protects mice from LPS-induced hepatitis.

    PubMed

    Mochizuki, Shinichi; Sakurai, Kazuo

    2011-04-30

    Antisense therapy, the first concept of oligonucleotide therapeutics, was proposed more than two decades ago. However, the lack of suitable delivering carriers continues to be a major obstacle to practical therapy. In this study, we present a novel complex consisting of β-1,3-glucan and antisense oligonucleotide (AS-ODN) as a new candidate of the carriers. We used schizophyllan (SPG) as a β-1,3-glucan and an AS-ODN sequence to suppress tumor necrosis factor alpha (TNF-α), where the AS-ODN has a (dA)(60) tail to induce complex with SPG. When the complexes were applied to peritoneal macrophages, they were incorporated into the cells via dectin-1 (a β-1,3-glucan receptor expressed on antigen presenting cells) and suppressed lipopolysaccharide (LPS)-induced TNF-α secretion. In-vivo, AS-ODN/SPG decreased the secretion of TNF-α in serum and drastically reduced the inflammation of LPS-induced hepatitis. This new complex could overcome the long outstanding problem for antisense therapy because of its complexation ability, non-toxicity and high target specificity. PMID:21281680

  1. Early adenosine release contributes to hypoxia-induced disruption of stimulus-induced sharp wave-ripple complexes in rat hippocampal area CA3.

    PubMed

    Jarosch, Marlene S; Gebhardt, Christine; Fano, Silvia; Huchzermeyer, Christine; Ul Haq, Rizwan; Behrens, Christoph J; Heinemann, Uwe

    2015-07-01

    We investigated the effects of hypoxia on sharp wave-ripple complex (SPW-R) activity and recurrent epileptiform discharges in rat hippocampal slices, and the mechanisms underlying block of this activity. Oxygen levels were measured using Clark-style oxygen sensor microelectrodes. In contrast to recurrent epileptiform discharges, oxygen consumption was negligible during SPW-R activity. These network activities were reversibly blocked when oxygen levels were reduced to 20% or less for 3 min. The prolongation of hypoxic periods to 6 min caused reversible block of SPW-Rs during 20% oxygen and irreversible block when 0% oxygen (anoxia) was applied. In contrast, recurrent epileptiform discharges were more resistant to prolonged anoxia and almost fully recovered after 6 min of anoxia. SPW-Rs were unaffected by the application of 1-butyl-3-(4-methylphenylsulfonyl) urea, a blocker of KATP channels, but they were blocked by activation of adenosine A1 receptors. In support of a modulatory function of adenosine, the amplitude and incidence of SPW-Rs were increased during application of the A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). Interestingly, hypoxia decreased the frequency of miniature excitatory post-synaptic currents in CA3 pyramidal cells, an effect that was converted into increased frequency by the adenosine A1 agonist DPCPX. In addition, DPCPX also delayed the onset of hypoxia-mediated block of SPW-Rs. Our data suggest that early adenosine release during hypoxia induces a decrease in pre-synaptic glutamate release and that both might contribute to transient block of SPW-Rs during hypoxia/anoxia in area CA3. PMID:25959377

  2. DNA–PKcs–SIN1 complexation mediates low-dose X-ray irradiation (LDI)-induced Akt activation and osteoblast differentiation

    SciTech Connect

    Xu, Yong; Fang, Shi-ji; Zhu, Li-juan; Zhu, Lun-qing; Zhou, Xiao-zhong

    2014-10-24

    Highlights: • LDI increases ALP activity, promotes type I collagen (Col I)/Runx2 mRNA expression. • LDI induces DNA–PKcs activation, which is required for osteoblast differentiation. • Akt activation mediates LDI-induced ALP activity and Col I/Runx2 mRNA increase. • DNA–PKcs–SIN1 complexation mediates LDI-induced Akt Ser-473 phosphorylation. • DNA–PKcs–SIN1 complexation is important for osteoblast differentiation. - Abstract: Low-dose irradiation (LDI) induces osteoblast differentiation, however the underlying mechanisms are not fully understood. In this study, we explored the potential role of DNA-dependent protein kinase catalytic subunit (DNA–PKcs)–Akt signaling in LDI-induced osteoblast differentiation. We confirmed that LDI promoted mouse calvarial osteoblast differentiation, which was detected by increased alkaline phosphatase (ALP) activity as well as mRNA expression of type I collagen (Col I) and runt-related transcription factor 2 (Runx2). In mouse osteoblasts, LDI (1 Gy) induced phosphorylation of DNA–PKcs and Akt (mainly at Ser-473). The kinase inhibitors against DNA–PKcs (NU-7026 and NU-7441) or Akt (LY294002, perifosine and MK-2206), as well as partial depletion of DNA–PKcs or Akt1 by targeted-shRNA, dramatically inhibited LDI-induced Akt activation and mouse osteoblast differentiation. Further, siRNA-knockdown of SIN1, a key component of mTOR complex 2 (mTORC2), also inhibited LDI-induced Akt Ser-473 phosphorylation as well as ALP activity increase and Col I/Runx2 expression in mouse osteoblasts. Co-immunoprecipitation (Co-IP) assay results demonstrated that LDI-induced DNA–PKcs–SIN1 complexation, which was inhibited by NU-7441 or SIN1 siRNA-knockdown in mouse osteoblasts. In summary, our data suggest that DNA–PKcs–SIN1 complexation-mediated Akt activation (Ser-473 phosphorylation) is required for mouse osteoblast differentiation.

  3. Mixed-ligand copper(II) complexes activate aryl hydrocarbon receptor AhR and induce CYP1A genes expression in human hepatocytes and human cell lines.

    PubMed

    Kubešová, Kateřina; Dořičáková, Aneta; Trávníček, Zdeněk; Dvořák, Zdeněk

    2016-07-25

    The effects of four copper(II) mixed-ligand complexes [Cu(qui1)(L)]NO3·H2O (1-3) and [Cu(qui2)(phen)]NO3 (4), where qui1=2-phenyl-3-hydroxy-4(1H)-quinolinone, Hqui2=2-(4-amino-3,5-dichlorophenyl)-N-propyl-3-hydroxy-4(1H)-quinolinone-7-carboxamide, L=1,10-phenanthroline (phen) (1), 5-methyl-1,10-phenanthroline (mphen) (2), bathophenanthroline (bphen) (3), on transcriptional activities of steroid receptors, nuclear receptors and xenoreceptors have been studied. The complexes (1-4) did not influence basal or ligand-inducible activities of glucocorticoid receptor, androgen receptor, thyroid receptor, pregnane X receptor and vitamin D receptor, as revealed by gene reporter assays. The complexes 1 and 2 dose-dependently induced luciferase activity in stable gene reporter AZ-AhR cell line, and this induction was reverted by resveratrol, indicating involvement of aryl hydrocarbon receptor (AhR) in the process. The complexes 1, 2 and 3 induced CYP1A1 mRNA in LS180 cells and CYP1A1/CYP1A2 in human hepatocytes through AhR. Electrophoretic mobility shift assay EMSA showed that the complexes 1 and 2 transformed AhR in its DNA-binding form. Collectively, we demonstrate that the complexes 1 and 2 activate AhR and induce AhR-dependent genes in human hepatocytes and cancer cell lines. In conclusion, the data presented here might be of toxicological importance, regarding the multiple roles of AhR in human physiology and pathophysiology. PMID:27180721

  4. ATM protein is indispensable to repair complex-type DNA double strand breaks induced by high LET heavy ion irradiation.

    NASA Astrophysics Data System (ADS)

    Sekine, Emiko; Yu, Dong; Fujimori, Akira; Anzai, Kazunori; Okayasu, Ryuichi

    ATM (ataxia telangiectasia-mutated) protein responsible for a rare genetic disease with hyperradiosensitivity, is the one of the earliest repair proteins sensing DNA double-strand breaks (DSB). ATM is known to phosphorylate DNA repair proteins such as MRN complex (Mre11, Rad50 and NBS1), 53BP1, Artemis, Brca1, gamma-H2AX, and MDC. We studied the interactions between ATM and DNA-PKcs, a crucial NHEJ repair protein, after cells exposure to high and low LET irradiation. Normal human (HFL III, MRC5VA) and AT homozygote (AT2KY, AT5BIVA, AT3BIVA) cells were irradiated with X-rays and high LET radiation (carbon ions: 290MeV/n initial energy at 70 keV/um, and iron ions: 500MeV/n initial energy at 200KeV/um), and several critical end points were examined. AT cells with high LET irradiation showed a significantly higher radiosensitivity when compared with normal cells. The behavior of DNA DSB repair was monitored by immuno-fluorescence techniques using DNA-PKcs (pThr2609, pSer2056) and ATM (pSer1981) antibodies. In normal cells, the phosphorylation of DNA-PKcs was clearly detected after high LET irradiation, though the peak of phosphorylation was delayed when compared to X-irradiation. In contrast, almost no DNA-PKcs phosphorylation foci were detected in AT cells irradiated with high LET radiation. A similar result was also observed in normal cells treated with 10 uM ATM kinase specific inhibitor (KU55933) one hour before irradiation. These data suggest that the phosphorylation of DNA-PKcs with low LET X-rays is mostly ATM-independent, and the phosphorylation of DNA-PKcs with high LET radiation seems to require ATM probably due to its complex nature of DSB induced. Our study indicates that high LET heavy ion irradiation which we can observe in the space environment would provide a useful tool to study the fundamental mechanism associated with DNA DSB repair.

  5. Winter storm-induced hydrodynamics and morphological response of a shallow transgressive shoal complex: Northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Siadatmousavi, S. Mostafa; Jose, Felix

    2015-03-01

    Using extended deployments during seasons of low and high discharge from the Atchafalaya River, meteorological, hydrodynamic and bottom boundary layer parameters were monitored from Tiger and Trinity Shoal complex, off Louisiana coast, USA. During winter storms, the surface current speed measured at both shoals exceeded 0.5 m/s and the entire water column followed the prevailing wind direction. The current speed close to the bottom exceeded 0.3 m/s during high energy northerly winds. The mean water level in the shoal complex increased during southerly winds and decreased during northerly winds, such that the difference between wind set-up and set-down exceeded 0.7 m in Tiger Shoal and 0.6 m in Trinity Shoal during high energy frontal passages. The swell height was inversely correlated with mean water level, and increased during pre-frontal phase and decreased during post-frontal phase of winter storms. The sea (short waves) height responded quickly to wind direction and speed; and within a few hours after the wind shifted and blowing from the north, the sea height increased during both deployments. Bimodal wave frequency spectrum was observed during wind veering from southerly to northerly, when both sea and swell intensities were significant. The Tiger Shoal bed sediment texture transformed drastically, from mud to shell and shell hash assemblage, within a period of two weeks during the December 2008 deployment. Backscatter signal intensity from a Pulse Coherent Acoustic Doppler Profiler (PCADP) and its velocity estimates were used to determine the vertical extend and timing of mud resuspension and their eventual flushing out from the shoal environment, when exposed to high energy winter storm passages. The computed time frame for a total transformation of bottom sediment texture (from muddy bottom to shell and shell hash assemblage) was supported by the combined wave and bottom current induced shear stress at shoal bed. The bed samples collected from Tiger Shoal

  6. SYNAPTONEMAL COMPLEX DAMAGE INDUCED BY CLASTOGENIC AND ANTI-MITOTIC CHEMICALS: IMPLICATIONS FOR NON-DISJUNCTION AND ANEUPLOIDY (JOURNAL VERSION)

    EPA Science Inventory

    Mice were treated with mitomycin C, cyclophosphamide, amuscarine, colchicine, or vinblastine sulfate, and meiotic prophase cells analyzed for synaptonemal complex damage. All test agents caused synaptonemal complex breakage and synapsis irregularities, although propensities for i...

  7. Synchronization of Isolated Downstates (K-Complexes) May Be Caused by Cortically-Induced Disruption of Thalamic Spindling

    PubMed Central

    Mak-McCully, Rachel A.; Deiss, Stephen R.; Rosen, Burke Q.; Jung, Ki-Young; Sejnowski, Terrence J.; Bastuji, Hélène; Rey, Marc

    2014-01-01

    Sleep spindles and K-complexes (KCs) define stage 2 NREM sleep (N2) in humans. We recently showed that KCs are isolated downstates characterized by widespread cortical silence. We demonstrate here that KCs can be quasi-synchronous across scalp EEG and across much of the cortex using electrocorticography (ECOG) and localized transcortical recordings (bipolar SEEG). We examine the mechanism of synchronous KC production by creating the first conductance based thalamocortical network model of N2 sleep to generate both spontaneous spindles and KCs. Spontaneous KCs are only observed when the model includes diffuse projections from restricted prefrontal areas to the thalamic reticular nucleus (RE), consistent with recent anatomical findings in rhesus monkeys. Modeled KCs begin with a spontaneous focal depolarization of the prefrontal neurons, followed by depolarization of the RE. Surprisingly, the RE depolarization leads to decreased firing due to disrupted spindling, which in turn is due to depolarization-induced inactivation of the low-threshold Ca2+ current (IT). Further, although the RE inhibits thalamocortical (TC) neurons, decreased RE firing causes decreased TC cell firing, again because of disrupted spindling. The resulting abrupt removal of excitatory input to cortical pyramidal neurons then leads to the downstate. Empirically, KCs may also be evoked by sensory stimuli while maintaining sleep. We reproduce this phenomenon in the model by depolarization of either the RE or the widely-projecting prefrontal neurons. Again, disruption of thalamic spindling plays a key role. Higher levels of RE stimulation also cause downstates, but by directly inhibiting the TC neurons. SEEG recordings from the thalamus and cortex in a single patient demonstrated the model prediction that thalamic spindling significantly decreases before KC onset. In conclusion, we show empirically that KCs can be widespread quasi-synchronous cortical downstates, and demonstrate with the first model

  8. Nonesterified Fatty Acid-Induced Endoplasmic Reticulum Stress in Cattle Cumulus Oocyte Complexes Alters Cell Metabolism and Developmental Competence.

    PubMed

    Sutton-McDowall, Melanie L; Wu, Linda L Y; Purdey, Malcolm; Abell, Andrew D; Goldys, Ewa M; MacMillan, Keith L; Thompson, Jeremy G; Robker, Rebecca L

    2016-01-01

    Reduced oocyte quality has been associated with poor fertility of high-performance dairy cows during peak lactation, due to negative energy balance. We examined the role of nonesterified fatty acids (NEFAs), known to accumulate within follicular fluid during under- and overnutrition scenarios, in causing endoplasmic reticulum (ER) stress of in vitro maturated cattle cumulus-oocyte complexes (COCs). NEFA concentrations were: palmitic acid (150 μM), oleic acid (200 μM), and steric acid (75 μM). Abattoir-derived COCs were randomly matured for 24 h in the presence of NEFAs and/or an ER stress inhibitor, salubrinal. Total and hatched blastocyst yields were negatively impacted by NEFA treatment compared with controls, but this was reversed by salubrinal. ER stress markers, activating transcription factor 4 (Atf4) and heat shock protein 5 (Hspa5), but not Atf6, were significantly up-regulated by NEFA treatment within whole COCs but reversed by coincubation with salubrinal. Likewise, glucose uptake and lactate production, measured in spent medium samples, showed a similar pattern, suggesting that cumulus cell metabolism is sensitive to NEFAs via an ER stress-mediated process. In contrast, while mitochondrial DNA copy number was recovered in NEFA-treated oocytes, oocyte autofluorescence of the respiratory chain cofactor, FAD, was lower following NEFA treatment of COCs, and this was not reversed by salubrinal, suggesting the negative impact was via reduced mitochondrial function. These results reveal the significance of NEFA-induced ER stress on bovine COC developmental competence, revealing a potential therapeutic target for improving oocyte quality during peak lactation. PMID:26658709

  9. Fluid-induced dissolution breakdown of monazite from Tso Morari complex, NW Himalayas: evidence for immobility of trace elements

    NASA Astrophysics Data System (ADS)

    Upadhyay, Dewashish; Pruseth, Kamal Lochan

    2012-08-01

    Primary igneous monazite from the Polokongka La granite of the Tso Morari complex in the western Himalayas has been partially replaced by a three-layered corona of metamorphic fluor-apatite, allanite + U- and Th-bearing phases (huttonite + brabantite), and epidote. The alteration is related to high-pressure amphibolite-facies (10-11 kbar and 587-695 °C) fluid-induced retrogression of the ultra-high-pressure granite during exhumation after India-Asia collision. The corona textures can be explained by pseudomorphic partial replacement of the original monazite to apatite and allanite via a fluid-mediated coupled dissolution-reprecipitation process. Mass balance calculations using the volume proportions and compositions of coronal minerals show that the REE, U, Th, Pb, Ba and P were conserved and not transported outside the alteration corona. The formation of fluor-apatite, allanite, huttonite and coffinite from monazite and the immobility of REE, U and Th require an influx of alkali- and F-bearing, Ca-rich fluid having high Ca/Na into the corona. We are aware of only two other occurrences of such alteration textures, and these have several similarities in terms of geodynamic setting and P-T histories of the host rocks. We suggest that there may be a common mechanism of exhumation style, and source and composition of fluids during retrogression of granitoid rocks in collisional orogens and that such breakdown textures can be used to identify metagranites that have experienced high-P metamorphism in continental collision zones, which is otherwise difficult to constrain due to the high variance of the mineral assemblages in these rocks.

  10. The Role of Reactive Oxygen Species in Antibiotic-Induced Cell Death in Burkholderia cepacia Complex Bacteria

    PubMed Central

    Van Acker, Heleen; Gielis, Jan; Acke, Marloes; Cools, Freya; Cos, Paul

    2016-01-01

    It was recently proposed that bactericidal antibiotics, besides through specific drug-target interactions, kill bacteria by a common mechanism involving the production of reactive oxygen species (ROS). However, this mechanism involving the production of hydroxyl radicals has become the subject of a lot of debate. Since the contribution of ROS to antibiotic mediated killing most likely depends on the conditions, differences in experimental procedures are expected to be at the basis of the conflicting results. In the present study different methods (ROS specific stainings, gene-expression analyses, electron paramagnetic resonance, genetic and phenotypic experiments, detection of protein carbonylation and DNA oxidation) to measure the production of ROS upon antibiotic treatment in Burkholderia cepacia complex (Bcc) bacteria were compared. Different classes of antibiotics (tobramycin, ciprofloxacin, meropenem) were included, and both planktonic and biofilm cultures were studied. Our results indicate that some of the methods investigated were not sensitive enough to measure antibiotic induced production of ROS, including the spectrophotometric detection of protein carbonylation. Secondly, other methods were found to be useful only in specific conditions. For example, an increase in the expression of OxyR was measured in Burkholderia cenocepacia K56-2 after treatment with ciprofloxacin or meropenem (both in biofilms and planktonic cultures) but not after treatment with tobramycin. In addition results vary with the experimental conditions and the species tested. Nevertheless our data strongly suggest that ROS contribute to antibiotic mediated killing in Bcc species and that enhancing ROS production or interfering with the protection against ROS may form a novel strategy to improve antibiotic treatment. PMID:27438061

  11. Critical role of the major histocompatibility complex and IL-10 in matrilin-1-induced relapsing polychondritis in mice.

    PubMed

    Hansson, Ann-Sofie; Johansson, Asa C M; Holmdahl, Rikard

    2004-01-01

    Relapsing polychondritis (RP) is an autoimmune disease that affects extra-articular cartilage. Matrilin-1-induced relapsing polychondritis (MIRP) is a model for RP and is useful for studies of the pathogenic mechanisms in this disease. There are indications that the major histocompatibility complex (MHC) class II plays a major role in RP, since DR4+ patients are more commonly affected than controls. We have now addressed the role of the MHC region, as well as the non-MHC contribution, using congenic mouse strains. Of the MHC congenic strains, B10.Q (H2q) was the most susceptible, the B10.P (H2p) and B10.R (H2r) strains developed mild disease, while B10 strains carrying the v, b, f, or u H2 haplotypes were resistant. A slight variation of susceptibility of H2q strains (B10.Q> C3H.Q> DBA/1) was observed and the (B10.Q x DBA/1)F1 was the most susceptible of all strains. Furthermore, macrophages and CD4+ T cells were the most prominent cell types in inflammatory infiltrates of the tracheal cartilage. Macrophages are the major source of many cytokines, such as interleukin-10 (IL-10), which is currently being tested as a therapeutic agent in several autoimmune diseases. We therefore investigated B10.Q mice devoid of IL-10 through gene deletion and found that they developed a significantly more severe disease, with an earlier onset, than their heterozygous littermates. In conclusion, MHC genes, as well as non-MHC genes, are important for MIRP induction, and IL-10 plays a major suppressive role in cartilage inflammation of the respiratory tract. PMID:15380048

  12. Light Induced H2 Evolution from a Biophotocathode Based on Photosystem 1--Pt Nanoparticles Complexes Integrated in Solvated Redox Polymers Films.

    PubMed

    Zhao, Fangyuan; Conzuelo, Felipe; Hartmann, Volker; Li, Huaiguang; Nowaczyk, Marc M; Plumeré, Nicolas; Rögner, Matthias; Schuhmann, Wolfgang

    2015-10-29

    We report on a biophotocathode based on photosystem 1 (PS1)-Pt nanoparticle complexes integrated in a redox hydrogel for photoelectrocatalytic H2 evolution at low overpotential. A poly(vinyl)imidazole Os(bispyridine)2Cl polymer serves as conducting matrix to shuttle the electrons from the electrode to the PS1-Pt complexes embedded within the hydrogel. Light induced charge separation at the PS1-Pt complexes results in the generation of photocurrents (4.8 ± 0.4 μA cm(-2)) when the biophotocathodes are exposed to anaerobic buffer solutions. Under these conditions, the protons are the sole possible electron acceptors, suggesting that the photocurrent generation is associated with H2 evolution. Direct evidence for the latter process is provided by monitoring the H2 production with a Pt microelectrode in scanning electrochemical microscopy configuration over the redox hydrogel film containing the PS1-Pt complexes under illumination. PMID:26091401

  13. Spontaneous helical folding of bis(Ni-salphen) complexes in solution and in the solid state: spectroscopic tracking of the unfolding process induced by Na(+) ions.

    PubMed

    Achira, Hiroto; Ito, Muneyuki; Mutai, Toshiki; Yoshikawa, Isao; Araki, Koji; Houjou, Hirohiko

    2014-04-21

    Four kinds of bis(Ni-salphen) complexes containing a 2-methylenepropane-1,3-diyl linker were synthesised and characterised. Crystal structural analysis revealed that one of the complexes folded into a helical structure, in which two Ni atoms were at a distance of 3.2 Å from each other. NMR measurements suggested that a similar folded state was maintained in solution, and the energy barrier for refolding through an unfolded state was 47 kJ mol(-1). The folded complex also exhibited a significant bathochromic shift in its UV-Vis absorption structure. Addition of sodium ions caused unfolding of the complexes, and the corresponding spectra were attributed to a virtually isolated state. DFT calculations reproduced well the energy barrier and folding-induced bathochromic shift. PMID:24590352

  14. Reversal of nitric oxide-, peroxynitrite- and S-nitrosothiol-induced inhibition of mitochondrial respiration or complex I activity by light and thiols.

    PubMed

    Borutaite, V; Budriunaite, A; Brown, G C

    2000-08-15

    Nitric oxide (NO) and its derivatives peroxynitrite and S-nitrosothiols inhibit mitochondrial respiration by various means, but the mechanisms and/or the reversibility of such inhibitions are not clear. We find that the NO-induced inhibition of respiration in isolated mitochondria due to inhibition of cytochrome oxidase is acutely reversible by light. Light also acutely reversed the inhibition of respiration within iNOS-expressing macrophages, and this reversal was partly due to light-induced breakdown of NO, and partly due to reversal of the NO-induced inhibition of cytochrome oxidase. NO did not cause inhibition of complex I activity within isolated mitochondria, but 0.34 mM peroxynitrite, 1 mM S-nitroso-N-acetylpenicillamine or 1 mM S-nitrosoglutathione did cause substantial inhibition of complex I activity. Inhibition by these reagents was reversed by light, dithiothreitol or glutathione-ethyl ester, either partially or completely, depending on the reagent used. The rapid inhibition of complex I activity by S-nitroso-N-acetylpenicillamine also occurred in conditions where there was little or no release of free NO, suggesting that the inhibition was due to transnitrosylation of the complex. These findings have implications for the physiological and pathological regulation of respiration by NO and its derivatives. PMID:11004457

  15. Glutamine supplementation attenuates ethanol-induced disruption of apical junctional complexes in colonic epithelium and ameliorates gut barrier dysfunction and fatty liver in mice.

    PubMed

    Chaudhry, Kamaljit K; Shukla, Pradeep K; Mir, Hina; Manda, Bhargavi; Gangwar, Ruchika; Yadav, Nikki; McMullen, Megan; Nagy, Laura E; Rao, RadhaKrishna

    2016-01-01

    Previous in vitro studies showed that glutamine (Gln) prevents acetaldehyde-induced disruption of tight junctions and adherens junctions in Caco-2 cell monolayers and human colonic mucosa. In the present study, we evaluated the effect of Gln supplementation on ethanol-induced gut barrier dysfunction and liver injury in mice in vivo. Ethanol feeding caused a significant increase in inulin permeability in distal colon. Elevated permeability was associated with a redistribution of tight junction and adherens junction proteins and depletion of detergent-insoluble fractions of these proteins, suggesting that ethanol disrupts apical junctional complexes in colonic epithelium and increases paracellular permeability. Ethanol-induced increase in colonic mucosal permeability and disruption of junctional complexes were most severe in mice fed Gln-free diet. Gln supplementation attenuated ethanol-induced mucosal permeability and disruption of tight junctions and adherens junctions in a dose-dependent manner, indicating the potential role of Gln in nutritional intervention to alcoholic tissue injury. Gln supplementation dose-dependently elevated reduced-protein thiols in colon without affecting the level of oxidized-protein thiols. Ethanol feeding depleted reduced protein thiols and elevated oxidized protein thiols. Ethanol-induced protein thiol oxidation was most severe in mice fed with Gln-free diet and absent in mice fed with Gln-supplemented diet, suggesting that antioxidant effect is one of the likely mechanisms involved in Gln-mediated amelioration of ethanol-induced gut barrier dysfunction. Ethanol feeding elevated plasma transaminase and liver triglyceride, which was accompanied by histopathologic lesions in the liver; ethanol-induced liver damage was attenuated by Gln supplementation. These results indicate that Gln supplementation ameliorates alcohol-induced gut and liver injury. PMID:26365579

  16. A cyclopalladated complex interacts with mitochondrial membrane thiol-groups and induces the apoptotic intrinsic pathway in murine and cisplatin-resistant human tumor cells

    PubMed Central

    2011-01-01

    Background Systemic therapy for cancer metastatic lesions is difficult and generally renders a poor clinical response. Structural analogs of cisplatin, the most widely used synthetic metal complexes, show toxic side-effects and tumor cell resistance. Recently, palladium complexes with increased stability are being investigated to circumvent these limitations, and a biphosphinic cyclopalladated complex {Pd2 [S(-)C2, N-dmpa]2 (μ-dppe)Cl2} named C7a efficiently controls the subcutaneous development of B16F10-Nex2 murine melanoma in syngeneic mice. Presently, we investigated the melanoma cell killing mechanism induced by C7a, and extended preclinical studies. Methods B16F10-Nex2 cells were treated in vitro with C7a in the presence/absence of DTT, and several parameters related to apoptosis induction were evaluated. Preclinical studies were performed, and mice were endovenously inoculated with B16F10-Nex2 cells, intraperitoneally treated with C7a, and lung metastatic nodules were counted. The cytotoxic effects and the respiratory metabolism were also determined in human tumor cell lines treated in vitro with C7a. Results Cyclopalladated complex interacts with thiol groups on the mitochondrial membrane proteins, causes dissipation of the mitochondrial membrane potential, and induces Bax translocation from the cytosol to mitochondria, colocalizing with a mitochondrial tracker. C7a also induced an increase in cytosolic calcium concentration, mainly from intracellular compartments, and a significant decrease in the ATP levels. Activation of effector caspases, chromatin condensation and DNA degradation, suggested that C7a activates the apoptotic intrinsic pathway in murine melanoma cells. In the preclinical studies, the C7a complex protected against murine metastatic melanoma and induced death in several human tumor cell lineages in vitro, including cisplatin-resistant ones. The mitochondria-dependent cell death was also induced by C7a in human tumor cells. Conclusions The

  17. A tomato lycopene complex protects the kidney from cisplatin-induced injury via affecting oxidative stress as well as Bax, Bcl-2, and HSPs expression.

    PubMed

    Dogukan, Ayhan; Tuzcu, Mehmet; Agca, Can Ali; Gencoglu, Hasan; Sahin, Nurhan; Onderci, Muhittin; Ozercan, Ibrahim Hanifi; Ilhan, Necip; Kucuk, Omer; Sahin, Kazim

    2011-01-01

    Cisplatin-induced nephrotoxicity is related to an increase in oxidative stress in the kidney. Lycopene, a carotenoid found in tomatoes, is a potent dietary antioxidant. In the present study, we investigated the effect of the tomato lycopene complex against cisplatin-induced lipid peroxidation and nephrotoxicity in rats. Male Wistar rats (n = 28, 8 wk old, between 200-215 g) were divided into 4 groups: (a) control, (b) tomato lycopene complex (6 mg/kg, daily; consisting of 6% lycopene, 1.5% tocopherols, 1% phytoene and phytofluene, and 0.2% β-carotene), (c) cisplatin (7 mg/kg i.p., single dose), and (d) cisplatin + tomato lycopene complex. Cisplatin administration increased serum urea-N (171 vs. 37 mg/dl) and creatinine (1.80 vs. 0.42 mg/dl) and decreased body weight in comparison with the control rats (P < 0.001). Serum creatinine and urea-N levels were lower in rats treated with tomato lycopene complex + cisplatin compared with rats treated with cisplatin alone (P < 0.001). The renal tissue from the cisplatin-treated rats had greater malondialdehyde (MDA; 172 vs. 93 nmol/g) and 8-isoprostane levels (1810 vs. 610 pg/g) than that from the control rats (P < 0.001). Tomato lycopene complex prevented the rise of MDA and 8-isoprostane (P < 0.001). No measurable lycopene could be detected in the serum of the control and cisplatin-treated rats, whereas lycopene was observed in the serum of rats supplemented with tomato lycopene complex. Renal Bax protein expression was significantly higher in the cisplatin-treated rats than in the control rats, and tomato lycopene complex treatment significantly reduced Bax expression (P < 0.001). The expression of Bcl-2 was higher in tomato lycopene complex/cisplatin-treated rats than in the cisplatin-injected rats (P < 0.05). The expression of renal HSP60 and HSP70 was significantly lower in tomato lycopene complex + cisplatin-treated rats than in rats treated with cisplatin alone (P < 0.001). These results suggest that tomato lycopene

  18. On the possibility of lipid-induced regulation of conformation and immunogenicity of influenza a virus H1/N1 hemagglutinin as antigen of TI-complexes.

    PubMed

    Vorobieva, Natalia; Sanina, Nina; Vorontsov, Vladimir; Kostetsky, Eduard; Mazeika, Andrey; Tsybulsky, Alexander; Kim, Natalia; Shnyrov, Valery

    2014-01-01

    The tubular immunostimulating complex (TI-complex) consisting of cucumarioside A2-2, cholesterol and monogalactosyldiacylglycerol (MGDG) from marine macrophytes is the perspective antigen delivery system for subunit vaccines. MGDG is a lipid matrix for the protein antigen incorporated in the TI-complex. The aim of the present work was to study the influence of MGDGs from different macrophytes on conformation and immunogenicity of the secreted recombinant uncleaved hemagglutinin monomer (HA0S) of influenza A virus H1/N1. Differential scanning calorimetry, fluorescence spectroscopy and circular dichroism showed a dependence of the conformational changes of HA0S on the microviscosity of MGDG. The most viscous MGDG from Zostera marina induced the strongest rearrangements in protein conformation. Immunization of mice with HA0S within TI-complexes comprising different MGDGs resulted in an approximately 2-fold increase of the levels of anti-HA0S antibodies and granulocyte-macrophage colony-stimulating factor (GM-CSF) compared with those induced by HA0S alone. TI-complexes based on MGDG from Z. marina stimulated the maximal production of GM-CSF. However, humoral immune response (anti-HA0S antibodies), unlike cell-mediated immune response (GM-CSF), did not depend on the physicochemical properties of MGDGs. It is assumed that this is due to the different localization and conformational lipid sensitivity of the HA0S regions, which are responsible for these types of immune responses. PMID:25060667

  19. Novel access to azaphosphiridine complexes and first applications using Brønsted acid-induced ring expansion reactions.

    PubMed

    Fankel, Stefan; Helten, Holger; von Frantzius, Gerd; Schnakenburg, Gregor; Daniels, Jörg; Chu, Victoria; Müller, Christina; Streubel, Rainer

    2010-04-14

    Synthesis of azaphosphiridine complexes 3a-e was achieved via thermal group transfer reaction using 2H-azaphosphirene complex 1 and N-methyl C-aryl imines 2a-e (i) or via reaction of transient Li/Cl phosphinidenoid complex 5 (prepared from dichloro(organo)phosphane complex 4) using 2a-c (ii), respectively. Reaction of complexes 3a,d and trifluoromethane sulfonic acid in the presence of dimethyl cyanamide led to a highly bond- and regioselective ring expansion yielding 1,3,4sigma3lambda3-diazaphosphol-2-ene complexes 8a,d after deprotonation with NEt3. 31P NMR reaction monitoring revealed that protonation of complex 3a yields the azaphosphiridinium complex 6a, unambiguously identified by NMR spectroscopy at low temperature. All isolated products were characterized by multinuclear NMR spectroscopy, IR and UV/Vis (for 3a,d, 6a, 8a,d), MS and single-crystal X-ray crystallography in the cases of complexes 3b-d, 8a and 8d. DFT studies on the reaction mechanism and compliance constants of the model complex of 6a are presented. PMID:20379537

  20. Structural Insight for Roles of DR5 Death Domain Mutations on Oligomerization of DR5 Death Domain-FADD Complex in the Death-Inducing Signaling Complex Formation: A Computational Study.

    PubMed

    Yang, Hongyi; Song, Yuhua

    2016-04-01

    Death receptor 5 (DR5)-induced apoptosis that prioritizes the death of tumor cells has been proposed as one of the promising cancer therapies. In this process, oligomerized DR5 death domain (DD) binding to Fas-associated death domain (FADD) leads to FADD activating caspase-8, which marks the formation of the death-inducing signaling complex (DISC) that initiates apoptosis. DR5 DD mutations found in cancer cells have been suggested to play an important pathological role, the mechanism through which those mutants prevent the DR5-activated DISC formation is not clear yet. This study sought to provide structural and molecular insight for the roles of four selected DR5 DD mutations (E355K, E367K, K415N, and L363F) in the oligomerization of DR5 DD-FADD complex during the DISC formation. Results from the molecular dynamics simulations show that the simulated mutants induce conformational, dynamical motions and interactions changes in the DR5 DD-FADD tetramer complex, including changes in a protein's backbone flexibility, less exposure of FADD DED's caspase-8 binding site, reduced H-bonding and hydrophobic contacts at the DR5 DD-FADD DD binding, altered distribution of the electrostatic potentials and correlated motions of residues, and reduced binding affinity of DR5 DD binding to FADD. This study provides structural and molecular insight for the influence of DR5 DD mutations on oligomerization of DR5 DD-FADD complex, which is expected to foster understanding of the DR5 DD mutants' resistance mechanism against DR5-activated DISC formation. PMID:26995783

  1. Surface-Induced Dissociation Mass Spectra as a Tool for Distinguishing Different Structural Forms of Gas-Phase Multimeric Protein Complexes.

    PubMed

    Quintyn, Royston S; Zhou, Mowei; Yan, Jing; Wysocki, Vicki H

    2015-12-01

    One attractive feature of ion mobility mass spectrometry (IM-MS) lies in its ability to provide experimental collision cross section (CCS) measurements, which can be used to distinguish different conformations that a protein complex may adopt during its gas-phase unfolding. However, CCS values alone give no detailed information on subunit structure within the complex. Consequently, structural characterization typically requires molecular modeling, which can have uncertainties without experimental support. One method of obtaining direct experimental evidence on the structures of these intermediates is utilizing gas-phase activation techniques that can effectively dissociate the complexes into substructures while preserving the native topological information. The most commonly used activation method, collision-induced dissociation (CID) with low-mass target gases, typically leads to unfolding of monomers of a protein complex. Here, we describe a method that couples IM-MS and surface-induced dissociation (SID) to dissociate the source-activated precursors of three model protein complexes: C-reactive protein (CRP), transthyretin (TTR), and concanavalin A (Con A). The results of this study confirm that CID involves the unfolding of the protein complex via several intermediates. More importantly, our experiments also indicate that retention of similar CCS between different intermediates does not guarantee retention of structure. Although CID spectra (at a given collision energy) of source-activated, mass-selected precursors do not distinguish between native-like, collapsed, and expanded forms of a protein complex, dissociation patterns and/or average charge states of monomer products in SID of each of these forms are unique. PMID:26499904

  2. Compartmentalized Accumulation of cAMP near Complexes of Multidrug Resistance Protein 4 (MRP4) and Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Contributes to Drug-induced Diarrhea*

    PubMed Central

    Moon, Changsuk; Zhang, Weiqiang; Ren, Aixia; Arora, Kavisha; Sinha, Chandrima; Yarlagadda, Sunitha; Woodrooffe, Koryse; Schuetz, John D.; Valasani, Koteswara Rao; de Jonge, Hugo R.; Shanmukhappa, Shiva Kumar; Shata, Mohamed Tarek M.; Buddington, Randal K.; Parthasarathi, Kaushik; Naren, Anjaparavanda P.

    2015-01-01

    Diarrhea is one of the most common adverse side effects observed in ∼7% of individuals consuming Food and Drug Administration (FDA)-approved drugs. The mechanism of how these drugs alter fluid secretion in the gut and induce diarrhea is not clearly understood. Several drugs are either substrates or inhibitors of multidrug resistance protein 4 (MRP4), such as the anti-colon cancer drug irinotecan and an anti-retroviral used to treat HIV infection, 3′-azido-3′-deoxythymidine (AZT). These drugs activate cystic fibrosis transmembrane conductance regulator (CFTR)-mediated fluid secretion by inhibiting MRP4-mediated cAMP efflux. Binding of drugs to MRP4 augments the formation of MRP4-CFTR-containing macromolecular complexes that is mediated via scaffolding protein PDZK1. Importantly, HIV patients on AZT treatment demonstrate augmented MRP4-CFTR complex formation in the colon, which defines a novel paradigm of drug-induced diarrhea. PMID:25762723

  3. Electrophoretic behavior of DNA-methyl-CpG-binding domain protein complexes revealed by capillary electrophoreses laser-induced fluorescence.

    PubMed

    Zhong, Shangwei; Zou, Dandan; Zhao, Bailin; Zhang, Dapeng; Li, Xiangjun; Wang, Hailin

    2015-12-01

    The free solution electrophoretic behavior of DNA-protein complexes depends on their charge and mass in a certain experimental condition, which are two fundamental properties of DNA-protein complexes in free solution. Here, we used CE LIF to study the free solution behavior of DNA-methyl-CpG-binding domain protein (MBD2b) complexes through exploring the relationship between the mobilities, charge, and mass of DNA-protein complexes. This method is based on the effective separation of free DNA and DNA-protein complexes because of their different electrophoretic mobility in a certain electric field. In order to avoid protein adsorption, a polyacrylamide-coated capillary was used. Based on the evaluation of the electrophoretic behavior of formed DNA-MBD2b complexes, we found that the values of (μ0 /μ)-1 were directly proportional to the charge-to-mass ratios of formed complexes, where the μ0 and μ are the mobility of free DNA probe and DNA-protein complex, respectively. The models were further validated by the complex mobilities of protein with various lengths of DNA probes. The deviation of experimental and calculated charge-to-mass ratios of formed complexes from the theoretical data was less than 10%, suggesting that our models are useful to analyze the DNA-binding properties of the purified MBD2b protein and help to analyze other DNA-protein complexes. Additionally, this study enhances the understanding of the influence of the charge-to-mass ratios of formed DNA-protein complexes on their separation and electrophoretic behaviors. PMID:26377303

  4. Neuropeptide S ameliorates olfactory spatial memory impairment induced by scopolamine and MK801 through activation of cognate receptor-expressing neurons in the subiculum complex.

    PubMed

    Shao, Yu-Feng; Wang, Can; Xie, Jun-Fan; Kong, Xiang-Pan; Xin, Le; Dong, Chao-Yu; Li, Jing; Ren, Wen-Ting; Hou, Yi-Ping

    2016-07-01

    Our previous studies have demonstrated that neuropeptide S (NPS), via selective activation of the neurons bearing NPS receptor (NPSR) in the olfactory cortex, facilitates olfactory function. High level expression of NPSR mRNA in the subiculum complex of hippocampal formation suggests that NPS-NPSR system might be involved in the regulation of olfactory spatial memory. The present study was undertaken to investigate effects of NPS on the scopolamine- or MK801-induced impairment of olfactory spatial memory using computer-assisted 4-hole-board spatial memory test, and by monitoring Fos expression in the subiculum complex in mice. In addition, dual-immunofluorescence microscopy was employed to identify NPS-induced Fos-immunereactive (-ir) neurons that also bear NPSR. Intracerebroventricular administration of NPS (0.5 nmol) significantly increased the number of visits to switched odorants in recall trial in mice suffering from odor-discriminating inability induced by scopolamine, a selective muscarinic cholinergic receptor antagonist, or MK801, a N-methyl-D-aspartate receptor antagonist, after training trials. The improvement of olfactory spatial memory by NPS was abolished by the NPSR antagonist [D-Val(5)]NPS (40 nmol). Ex vivo c-Fos and NPSR immunohistochemistry revealed that, as compared with vehicle-treated mice, NPS markedly enhanced Fos expression in the subiculum complex encompassing the subiculum (S), presubiculum (PrS) and parasubiculum (PaS). The percentages of Fos-ir neurons that also express NPSR were 91.3, 86.5 and 90.0 % in the S, PrS and PaS, respectively. The present findings demonstrate that NPS, via selective activation of the neurons bearing NPSR in the subiculum complex, ameliorates olfactory spatial memory impairment induced by scopolamine and MK801 in mice. PMID:26323488

  5. Immunization with antigenic peptides complexed with β-glucan induces potent cytotoxic T-lymphocyte activity in combination with CpG-ODNs.

    PubMed

    Mochizuki, Shinichi; Morishita, Hiromi; Kobiyama, Kouji; Aoshi, Taiki; Ishii, Ken J; Sakurai, Kazuo

    2015-12-28

    The induction of antigen-specific immune responses requires immunization with not only antigens, but also adjuvants. CpG oligonucleotides (CpG-ODNs) are well-known ligands for Toll-like receptor 9 and a potent adjuvant that induces both Th1-type humoral and cellular immune responses including cytotoxic T-lymphocyte responses. We previously demonstrated that β-glucan schizophyllan (SPG) can form complexes with CpG-ODNs with attached dA40 (CpG-dA/SPG), which can accumulate in macrophages in the draining inguinal lymph nodes and induce strong immune responses by co-administration of antigenic proteins, namely ovalbumin (OVA). Immunization with antigenic peptides, OVA257-264, did not induce these antigen-specific immune responses even in combination with CpG-dA/SPG, indicating that peptides require a carrier to antigen presenting cells. In this study, we prepared conjugates comprising OVA257-264 and dA40, and made complexes with SPG. Immunization with OVA257-264-dA/SPG induced peptide-specific immune responses in combination with CpG-dA regardless of complexation with SPG both in vitro and in vivo. When splenocytes from immunized mice were incubated with E.G7-OVA tumor model cells presenting OVA peptides, the number of cells drastically decreased after 24h. Furthermore, mice pre-immunized with OVA257-264-dA/SPG and CpG-ODNs exhibited a long delay in tumor growth after tumor inoculation. Therefore, these peptide-dA/SPG and CpG-dA/SPG complexes could be used as a potent vaccine for the treatment of cancers and infectious diseases. PMID:26562685

  6. Ternary complex consisting of DNA, polycation, and a natural polysaccharide of schizophyllan to induce cellular uptake by antigen presenting cells.

    PubMed

    Takeda, Yoichi; Shimada, Naohiko; Kaneko, Kenji; Shinkai, Seiji; Sakurai, Kazuo

    2007-04-01

    A natural polysaccharide called schizophyllan (SPG) can form a complex with polynucleotides, and the complex has been shown to deliver biofunctional short DNAs such as antisense DNAs and CpG-DNAs. Although it is a novel and efficient method, there is a drawback: attachment of homo-polynucleotide tails [for example, poly(dA) or poly(C)] to the end of DNA is necessary to stabilize the complex, because DNA heterosequences cannot bind to SPG. The aim of this paper is to present an alternative method in which SPG/DNA complexes can be made without using the tails. The basic strategy is as follows: since SPG can form hydrophobic domains in aqueous solutions, hydrophobic objects should be encapsulated by this domain. DNA alone is highly hydrophilic; however, once DNA/polycation complexes are made, they should be included by the SPG hydrophobic domain. The aim of this paper is to prove the formation of the polycation/DNA/SPG ternary complex. Gel electrophoresis showed that presence of SPG influenced the migration pattern of polycation+DNA mixtures. With increasing the SPG ratio, the zeta potential (zeta) of the polycation+DNA+SPG mixture decreased drastically to reach almost zeta = 0 and the particle size distributions were altered due to the ternary complex formation. Confocal laser scanning microscopy revealed that the polycation/DNA/SPG ternary complexes showed high uptake efficiency when the complexes were exposed to macrophage-like cells (J774.A1). IL-12 secretion was enhanced when CpG-DNA was added as the ternary complex. These features can be ascribed to the fact that J774.A1 has a SPG recognition site called Dectin-1 on the cellular surface and the ternary complex can be ingested by this pathway. PMID:17328571

  7. L-Ornithine Schiff base-copper and -cadmium complexes as new proteasome inhibitors and apoptosis inducers in human cancer cells.

    PubMed

    Zhang, Zhongyu; Bi, Caifeng; Fan, Yuhua; Zhang, Nan; Deshmukh, Rahul; Yan, Xingchen; Lv, Xiuwen; Zhang, Pengfei; Zhang, Xia; Dou, Q Ping

    2015-01-01

    Ubiquitin-proteasome system (UPS) plays a crucial role in many cellular processes such as cell cycle, proliferation and apoptosis. Aberrant activation of UPS may result in cellular transformation or other altered pathological conditions. Previous studies have shown that metal-based complexes could inhibit proteasome activity and induce apoptosis in certain human cancer cells. In the current study, we report that the cadmium and copper complexes with heterocycle-ornithine Schiff base are potent inhibitors of proteasomal chymotrypsin-like (CT-like) activity, leading to induction of apoptosis in cancer cells. Two novel copper-containing complexes and two novel cadmium-containing complexes with different heterocycle-ornithine Schiff base structures as ligands were synthesized and characterized. We found that complexes Cu1, Cd1 and Cd2 show proteasome-inhibitory activities in human breast cancer MDA-MB-231 and human prostate cancer LNCaP cells, resulting in the accumulation of p27, a natural proteasome substrate and other ubiquitinated proteins, followed by the induction of apoptosis. Our results suggest that metal complexes with heterocycle-ornithine Schiff base have proteasome-inhibitory capabilities and have the potential to be developed into novel anticancer drugs. PMID:25467055

  8. Retinoic Acid Induces Ubiquitination-Resistant RIP140/LSD1 Complex to Fine-Tune Pax6 Gene in Neuronal Differentiation.

    PubMed

    Wu, Cheng-Ying; Persaud, Shawna D; Wei, Li-Na

    2016-01-01

    Receptor-interacting protein 140 (RIP140) is a wide-spectrum coregulator for hormonal regulation of gene expression, but its activity in development/stem cell differentiation is unknown. Here, we identify RIP140 as an immediate retinoic acid (RA)-induced dual-function chaperone for LSD1 (lysine-specific demethylase 1). RIP140 protects LSD1's catalytic domain and antagonizes its Jade-2-mediated ubiquitination and degradation. In RA-induced neuronal differentiation, the increased RIP140/LSD1 complex is recruited by RA-elevated Pit-1 to specifically reduce H3K4me2 modification on the Pax6 promoter, thereby repressing RA-induction of Pax6. This study reveals a new RA-induced gene repressive mechanism that modulates the abundance, enzyme quality, and recruitment of histone modifier LSD1 to neuronal regulator Pax6, which provides a homeostatic control for RA induction of neuronal differentiation. PMID:26372689

  9. Synthesis, interaction with DNA, cytotoxicity, cell cycle arrest and apoptotic inducing properties of ruthenium(II) molecular "light switch" complexes.

    PubMed

    Shobha Devi, C; Anil Kumar, D; Singh, Surya S; Gabra, Nazar; Deepika, N; Kumar, Y Praveen; Satyanarayana, S

    2013-06-01

    In an endeavor toward the development of metal-based anticancer drugs, we present here the design, synthesis and characterization of three ruthenium(II) functionalized phenanthroline complexes with extended π-conjugation. These complexes have been shown to act as promising CT-DNA intercalators as evidenced by UV-visible, luminescence, emission quenching by [Fe(CN)6](4-), DNA competitive binding with ethidium bromide and salt dependent studies. All three complexes [Ru(Hdpa)2PPIP](2+) (1), [Ru(Hdpa)2PIP](2+) (2), [Ru(Hdpa)24HEPIP](2+) (3) clearly demonstrated that they can bind to DNA through the intercalation mode. Cell viability experiments indicated that all complexes showed significant dose dependent cytotoxicity in selected cell lines. The apoptosis and cell cycle arrest were also investigated. The complexes were docked into DNA-base-pairs using the 'GOLD' (Genetic Optimization for Ligand Docking), docking program. PMID:23665797

  10. Repair pathways independent of the Fanconi anemia nuclear core complex play a predominant role in mitigating formaldehyde-induced DNA damage

    SciTech Connect

    Noda, Taichi; Takahashi, Akihisa; Kondo, Natsuko; Mori, Eiichiro; Okamoto, Noritomo; Nakagawa, Yosuke; Ohnishi, Ken; Zdzienicka, Malgorzata Z.; Thompson, Larry H.; Helleday, Thomas; Asada, Hideo; and others

    2011-01-07

    The role of the Fanconi anemia (FA) repair pathway for DNA damage induced by formaldehyde was examined in the work described here. The following cell types were used: mouse embryonic fibroblast cell lines FANCA{sup -/-}, FANCC{sup -/-}, FANCA{sup -/-}C{sup -/-}, FANCD2{sup -/-} and their parental cells, the Chinese hamster cell lines FANCD1 mutant (mt), FANCGmt, their revertant cells, and the corresponding wild-type (wt) cells. Cell survival rates were determined with colony formation assays after formaldehyde treatment. DNA double strand breaks (DSBs) were detected with an immunocytochemical {gamma}H2AX-staining assay. Although the sensitivity of FANCA{sup -/-}, FANCC{sup -/-} and FANCA{sup -/-}C{sup -/-} cells to formaldehyde was comparable to that of proficient cells, FANCD1mt, FANCGmt and FANCD2{sup -/-} cells were more sensitive to formaldehyde than the corresponding proficient cells. It was found that homologous recombination (HR) repair was induced by formaldehyde. In addition, {gamma}H2AX foci in FANCD1mt cells persisted for longer times than in FANCD1wt cells. These findings suggest that formaldehyde-induced DSBs are repaired by HR through the FA repair pathway which is independent of the FA nuclear core complex. -- Research highlights: {yields} We examined to clarify the repair pathways of formaldehyde-induced DNA damage. Formaldehyde induces DNA double strand breaks (DSBs). {yields} DSBs are repaired through the Fanconi anemia (FA) repair pathway. {yields} This pathway is independent of the FA nuclear core complex. {yields} We also found that homologous recombination repair was induced by formaldehyde.

  11. Paxillin mediates stretch-induced Rho signaling and endothelial permeability via assembly of paxillin-p42/44MAPK-GEF-H1 complex.

    PubMed

    Gawlak, Grzegorz; Tian, Yufeng; O'Donnell, James J; Tian, Xinyong; Birukova, Anna A; Birukov, Konstantin G

    2014-07-01

    Suboptimal ventilator support or regional ventilation heterogeneity in inflamed lungs causes excessive tissue distension, which triggers stretch-induced pathological signaling and may lead to vascular leak and lung dysfunction. Focal adhesions (FAs) are cell-substrate adhesive complexes participating in cellular mechanotransduction and regulation of the Rho GTPase pathway. Stretch-induced Rho regulation remains poorly understood. We used human lung endothelial cells (ECs) exposed to pathological cyclic stretch (CS) at 18% distension to test the hypothesis that FA protein paxillin participates in CS-induced Rho activation by recruiting the Rho-specific guanine nucleotide exchange factor GEF-H1. CS induced phosphorylation of paxillin and activated p42/44-MAP kinase, Rho GTPase, and paxillin/GEF-H1/p42/44-MAPK association. CS caused nearly 2-fold increase in EC permeability, which was attenuated by paxillin knockdown. Expression of the paxillin-Y31/118F phosphorylation mutant decreased the CS-induced paxillin/GEF-H1 association (16.3 ± 4.1%), GEF-H1 activation (28.9 ± 9.2%), and EC permeability (28.7 ± 8.1%) but not CS-induced p42/44-MAPK activation. Inhibition of p42/44-MAPK suppressed CS-induced paxillin/GEF-H1 interactions (15.9 ± 7.9%), GEF-H1 activation (11.7 ± 4.3%), and disruption of EC monolayer. Expression of GEF-H1T678A lacking p42/44-MAPK phosphorylation site attenuated Rho activation (31.2±11.6%). We conclude that MAPK-dependent targeting of GEF-H1 to paxillin is involved in the regulation of CS-induced Rho signaling and EC permeability. This study proposes a novel concept of paxillin-GEF-H1-p42/44-MAPK module as a regulator of pathological mechanotransduction.-Gawlak, G., Tian, Y., O'Donnell, J. J., III, Tian, X., Birukova, A. A., Birukov, K. G. Paxillin mediates stretch-induced Rho signaling and endothelial permeability via assembly of paxillin-p42/44MAPK-GEF-H1 complex. PMID:24706358

  12. 1918 Influenza virus hemagglutinin (HA) and the viral RNA polymerase complex enhance viral pathogenicity, but only HA induces aberrant host responses in mice.

    PubMed

    Watanabe, Tokiko; Tisoncik-Go, Jennifer; Tchitchek, Nicolas; Watanabe, Shinji; Benecke, Arndt G; Katze, Michael G; Kawaoka, Yoshihiro

    2013-05-01

    The 1918 pandemic influenza virus was the most devastating infectious agent in human history, causing fatal pneumonia and an estimated 20 to 50 million deaths worldwide. Previous studies indicated a prominent role of the hemagglutinin (HA) gene in efficient replication and high virulence of the 1918 virus in mice. It is, however, still unclear whether the high replication ability or the 1918 influenza virus HA gene is required for 1918 virus to exhibit high virulence in mice. Here, we examined the biological properties of reassortant viruses between the 1918 virus and a contemporary human H1N1 virus (A/Kawasaki/173/2001 [K173]) in a mouse model. In addition to the 1918 influenza virus HA, we demonstrated the role of the viral RNA replication complex in efficient replication of viruses in mouse lungs, whereas only the HA gene is responsible for lethality in mice. Global gene expression profiling of infected mouse lungs revealed that the 1918 influenza virus HA was sufficient to induce transcriptional changes similar to those induced by the 1918 virus, despite difference in lymphocyte gene expression. Increased expression of genes associated with the acute-phase response and the protein ubiquitination pathway were enriched during infections with the 1918 and 1918HA/K173 viruses, whereas reassortant viruses bearing the 1918 viral RNA polymerase complex induced transcriptional changes similar to those seen with the K173 virus. Taken together, these data suggest that HA and the viral RNA polymerase complex are critical determinants of Spanish influenza pathogenesis, but only HA, and not the viral RNA polymerase complex and NP, is responsible for extreme host responses observed in mice infected with the 1918 influenza virus. PMID:23449804

  13. Curcumin Pretreatment Prevents Potassium Dichromate-Induced Hepatotoxicity, Oxidative Stress, Decreased Respiratory Complex I Activity, and Membrane Permeability Transition Pore Opening

    PubMed Central

    García-Niño, Wylly Ramsés; Tapia, Edilia; Zazueta, Cecilia; Zatarain-Barrón, Zyanya Lucía; Hernández-Pando, Rogelio; Vega-García, Claudia Cecilia; Pedraza-Chaverrí, José

    2013-01-01

    Curcumin is a polyphenol derived from turmeric with recognized antioxidant properties. Hexavalent chromium is an environmental toxic and carcinogen compound that induces oxidative stress. The objective of this study was to evaluate the potential protective effect of curcumin on the hepatic damage generated by potassium dichromate (K2Cr2O7) in rats. Animals were pretreated daily by 9-10 days with curcumin (400 mg/kg b.w.) before the injection of a single intraperitoneal of K2Cr2O7 (15 mg/kg b.w.). Groups of animals were sacrificed 24 and 48 h later. K2Cr2O7-induced damage to the liver was evident by histological alterations and increase in the liver weight and in the activity of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and alkaline phosphatase in plasma. In addition, K2Cr2O7 induced oxidative damage in liver and isolated mitochondria, which was evident by the increase in the content of malondialdehyde and protein carbonyl and decrease in the glutathione content and in the activity of several antioxidant enzymes. Moreover, K2Cr2O7 induced decrease in mitochondrial oxygen consumption, in the activity of respiratory complex I, and permeability transition pore opening. All the above-mentioned alterations were prevented by curcumin pretreatment. The beneficial effects of curcumin against K2Cr2O7-induced liver oxidative damage were associated with prevention of mitochondrial dysfunction. PMID:23956771

  14. Naringin and Sertraline Ameliorate Doxorubicin-Induced Behavioral Deficits Through Modulation of Serotonin Level and Mitochondrial Complexes Protection Pathway in Rat Hippocampus.

    PubMed

    Kwatra, Mohit; Jangra, Ashok; Mishra, Murli; Sharma, Yogita; Ahmed, Sahabuddin; Ghosh, Pinaki; Kumar, Vikas; Vohora, Divya; Khanam, Razia

    2016-09-01

    The present study was designed to investigate the neuroprotective effect of naringin (NR) alone as well as its combination with sertraline (SRT) against doxorubicin (DOX)-induced neurobehavioral and neurochemical anomalies. DOX (15 mg/kg; i.p.) administration caused behavioral alterations, oxidative stress, neuroinflammation, mitochondrial dysfunction and monoamines alteration in male Wistar rats. NR (50 and 100 mg/kg; i.p.) and SRT (5 mg/kg; i.p.) treatment significantly attenuated DOX-induced anxiety and depressive-like behavior as evident from elevated plus maze (EPM) and modified forced swimming test (mFST), respectively. NR treatment significantly attenuated DOX-induced raised plasma corticosterone (CORT), tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) levels in the hippocampus (HC). Furthermore, we found that combination of NR and SRT regimen ameliorated DOX-induced behavioral anomalies through modulation of the 5-HT level and mitochondrial complexes protection pathway along with alleviation of oxidative stress in the HC region. Therefore, NR treatment alone or in combination with SRT could be beneficial against DOX-induced neurotoxicity. PMID:27209303

  15. Differential effects of buffer pH on Ca2+-induced ROS emission with inhibited mitochondrial complexes I and III

    PubMed Central

    Lindsay, Daniel P.; Camara, Amadou K. S.; Stowe, David F.; Lubbe, Ryan; Aldakkak, Mohammed

    2015-01-01

    Excessive mitochondrial reactive oxygen species (ROS) emission is a critical component in the etiology of ischemic injury. Complex I and complex III of the electron transport chain are considered the primary sources of ROS emission during cardiac ischemia and reperfusion (IR) injury. Several factors modulate ischemic ROS emission, such as an increase in extra-matrix Ca2+, a decrease in extra-matrix pH, and a change in substrate utilization. Here we examined the combined effects of these factors on ROS emission from respiratory complexes I and III under conditions of simulated IR injury. Guinea pig heart mitochondria were suspended in experimental buffer at a given pH and incubated with or without CaCl2. Mitochondria were then treated with either pyruvate, a complex I substrate, followed by rotenone, a complex I inhibitor, or succinate, a complex II substrate, followed by antimycin A, a complex III inhibitor. H2O2 release rate and matrix volume were compared with and without adding CaCl2 and at pH 7.15, 6.9, or 6.5 with pyruvate + rotenone or succinate + antimycin A to simulate conditions that may occur during in vivo cardiac IR injury. We found a large increase in H2O2 release with high [CaCl2] and pyruvate + rotenone at pH 6.9, but not at pHs 7.15 or 6.5. Large increases in H2O2 release rate also occurred at each pH with high [CaCl2] and succinate + antimycin A, with the highest levels observed at pH 7.15. The increases in H2O2 release were associated with significant mitochondrial swelling, and both H2O2 release and swelling were abolished by cyclosporine A, a desensitizer of the mitochondrial permeability transition pore (mPTP). These results indicate that ROS production by complex I and by complex III is differently affected by buffer pH and Ca2+ loading with mPTP opening. The study suggests that changes in the levels of cytosolic Ca2+ and pH during IR alter the relative amounts of ROS produced at mitochondrial respiratory complex I and complex III. PMID

  16. Synthesis and structural characterization of dioxomolybdenum and dioxotungsten hydroxamato complexes and their function in the protection of radiation induced DNA damage.

    PubMed

    Paul, Shiv Shankar; Selim, Md; Saha, Abhijit; Mukherjea, Kalyan K

    2014-02-21

    The synthesis and structural characterization of two novel dioxomolybdenum(VI) (1) and dioxotungsten(VI) (2) complexes with 2-phenylacetylhydroxamic acid (PAHH) [M(O)2(PAH)2] [M = Mo, W] have been accomplished. The dioxomolybdenum(VI) and dioxotungsten(VI) moiety is coordinated by the hydroxamate group (-CONHO(-)) of the 2-phenylacetylhydroxamate (PAH) ligand in a bi-dentate fashion. In both the complexes the PAHH ligand is coordinated through oxygen atoms forming a five membered chelate. The hydrogen atom of N-H of the hydroxamate group is engaged in intermolecular H-bonding with the carbonyl oxygen of another coordinated hydroxamate ligand, thereby forming an extended 1D chain. The ligand as well as both the complexes exhibit the ability to protect from radiation induced damage both in CTDNA as well as in pUC19 plasmid DNA. As the damage to DNA is caused by the radicals generated during radiolysis, its scavenging imparts protection from the damage to DNA. To understand the mechanism of protection, binding affinities of the ligand and the complex with DNA were determined using absorption and emission spectral studies and viscosity measurements, whereby the results indicate that both the complexes and the hydroxamate ligand interact with calf thymus DNA in the minor groove. The intrinsic binding constants, obtained from UV-vis studies, are 7.2 × 10(3) M(-1), 5.2 × 10(4) M(-1) and 1.2 × 10(4) M(-1) for the ligand and complexes 1 and 2 respectively. The Stern-Volmer quenching constants obtained from a luminescence study for both the complexes are 5.6 × 10(4) M(-1) and 1.6 × 10(4) M(-1) respectively. The dioxomolybdenum(VI) complex is found to be a more potent radioprotector compared to the dioxotungsten(VI) complex and the ligand. Radical scavenging chemical studies suggest that the complexes have a greater ability to scavenge both the hydroxyl as well as the superoxide radicals compared to the ligand. The free radical scavenging ability of the ligand and the

  17. Metal-assisted red light-induced DNA cleavage by ternary L-methionine copper(II) complexes of planar heterocyclic bases.

    PubMed

    Patra, Ashis K; Dhar, Shanta; Nethaji, Munirathinam; Chakravarty, Akhil R

    2005-03-01

    Ternary copper(II) complexes [Cu(l-met)B(Solv)](ClO4) (1-4), where B is a N,N-donor heterocyclic base like 2,2'-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq, 3) and dipyrido[3,2-a:2'],3'-c]phenazene (dppz, 4), are prepared and their DNA binding and photo-induced DNA cleavage activity studied (L-Hmet =L-methionine). Complex 2, structurally characterized by X-ray crystallography, shows a square pyramidal (4 + 1) coordination geometry in which the N,O-donor L-methionine and N,N-donor heterocyclic base bind at the basal plane and a solvent molecule is coordinated at the axial site. The complexes display a d-d band at approximately 600 nm in DMF and exhibit a cyclic voltammetric response due to the Cu(II)/Cu(I) couple near -0.1 V in DMF-Tris-HCl buffer. The complexes display significant binding propensity to the calf thymus DNA in the order: 4(dppz) > 3(dpq) > 2(phen> 1(bpy). Control cleavage experiments using pUC19 supercoiled DNA and distamycin suggest major groove binding for the dppz and minor groove binding for the other complexes. Complexes 2-4 show efficient DNA cleavage activity on UV (365 nm) or red light (632.8 nm) irradiation via a mechanistic pathway involving formation of singlet oxygen as the reactive species. The DNA cleavage activity of the dpq complex is found to be significantly more than its dppz and phen analogues. PMID:15726142

  18. An Lnc RNA (GAS5)/SnoRNA-derived piRNA induces activation of TRAIL gene by site-specifically recruiting MLL/COMPASS-like complexes

    PubMed Central

    He, Xin; Chen, Xinxin; Zhang, Xue; Duan, Xiaobing; Pan, Ting; Hu, Qifei; Zhang, Yijun; Zhong, Fudi; Liu, Jun; Zhang, Hong; Luo, Juan; Wu, Kang; Peng, Gao; Luo, Haihua; Zhang, Lehong; Li, Xiaoxi; Zhang, Hui

    2015-01-01

    PIWI-interacting RNA (piRNA) silences the transposons in germlines or induces epigenetic modifications in the invertebrates. However, its function in the mammalian somatic cells remains unknown. Here we demonstrate that a piRNA derived from Growth Arrest Specific 5, a tumor-suppressive long non-coding RNA, potently upregulates the transcription of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a proapoptotic protein, by inducing H3K4 methylation/H3K27 demethylation. Interestingly, the PIWIL1/4 proteins, which bind with this piRNA, directly interact with WDR5, resulting in a site-specific recruitment of the hCOMPASS-like complexes containing at least MLL3 and UTX (KDM6A). We have indicated a novel pathway for piRNAs to specially activate gene expression. Given that MLL3 or UTX are frequently mutated in various tumors, the piRNA/MLL3/UTX complex mediates the induction of TRAIL, and consequently leads to the inhibition of tumor growth. PMID:25779046

  19. ATP Depletion Via Mitochondrial F1F0 Complex by Lethal Factor is an Early Event in B. Anthracis-Induced Sudden Cell Death.

    PubMed

    Woodberry, Mitchell W; Aguilera-Aguirre, Leopoldo; Bacsi, Attila; Chopra, Ashok K; Kurosky, Alexander; Peterson, Johnny W; Boldogh, Istvan

    2009-01-01

    Bacillus anthracis' primary virulence factor is a tripartite anthrax toxin consisting of edema factor (EF), lethal factor (LF) and protective antigen (PA). In complex with PA, EF and LF are internalized via receptor-mediated endocytosis. EF is a calmodulin-dependent adenylate cyclase that induces tissue edema. LF is a zinc-metalloprotease that cleaves members of mitogen-activated protein kinase kinases. Lethal toxin (LT: PA plus LF)-induced death of macrophages is primarily attributed to expression of the sensitive Nalp1b allele, inflammasome formation and activation of caspase-1, but early events that initiate these processes are unknown. Here we provide evidence that an early essential event in pyroptosis of alveolar macrophages is LF-mediated depletion of cellular ATP. The underlying mechanism involves interaction of LF with F1F0-complex gamma and beta subunits leading to increased ATPase activity in mitochondria. In support, mitochondrial DNA-depleted MH-S cells have decreased F1F0 ATPase activity due to the lack of F06 and F08 polypeptides and show increased resistance to LT. We conclude that ATP depletion is an important early event in LT-induced sudden cell death and its prevention increases survival of toxin-sensitive cells. PMID:26124678

  20. Efficacy of Anakinra for Various Types of Crystal-Induced Arthritis in Complex Hospitalized Patients: A Case Series and Review of the Literature

    PubMed Central

    Aouba, A.; Deshayes, S.; Frenzel, L.; Decottignies, A.; Pressiat, C.; Bienvenu, B.; Boue, F.; Damaj, G.; Hermine, O.; Georgin-Lavialle, S.

    2015-01-01

    Background. There are few data on anakinra use after failure of conventional medications for crystal-induced peripheral arthritis and/or crowned dens syndrome among complex hospitalized patients. Methods. We retrospectively analyzed the outcome of six patients affected with subacute crystal-induced arthritis who had received anakinra in second or third line therapy, including three patients with crowned dens syndrome and three others with gouty arthritis. Patients' comorbidities, reasons for anakinra use and associated drugs, and outcomes were recorded. Results. All patients presented with elevated inflammatory syndrome, systemic symptoms with poly/oligoarthritis. Except for absolute contraindications, all patients were previously treated with full or decreased dose of NSAID, colchicine, and/or glucocorticoids, with unsatisfactory response. All three gouty patients exhibited complete responses in all acute involvements under anakinra within 3 to 5 days, including one of them who needed the reintroduction of colchicine treatment that was previously unsuccessful. Crowned dens syndrome patients, including two with pseudogout and one with subacute hydroxyapatite deposition disease, needed 9 to 11 days to achieve complete response. Tolerance to anakinra was good. Conclusion. In case series of complex hospitalized patients, anakinra showed good activity in crowned dens syndrome and associated crystal-induced peripheral arthritis, with longer treatment duration than in gouty arthritis. PMID:25922564

  1. A REDD1/TXNIP pro-oxidant complex regulates ATG4B activity to control stress-induced autophagy and sustain exercise capacity

    PubMed Central

    Qiao, Shuxi; Dennis, Michael; Song, Xiufeng; Vadysirisack, Douangsone D.; Salunke, Devika; Nash, Zachary; Yang, Zhifen; Liesa, Marc; Yoshioka, Jun; Matsuzawa, Shu-Ichi; Shirihai, Orian S.; Lee, Richard T.; Reed, John C.; Ellisen, Leif W.

    2015-01-01

    Macroautophagy (autophagy) is a critical cellular stress response; however, the signal transduction pathways controlling autophagy induction in response to stress are poorly understood. Here we reveal a new mechanism of autophagy control whose deregulation disrupts mitochondrial integrity and energy homeostasis in vivo. Stress conditions including hypoxia and exercise induce reactive oxygen species (ROS) through upregulation of a protein complex involving REDD1, an mTORC1 inhibitor and the pro-oxidant protein TXNIP. Decreased ROS in cells and tissues lacking either REDD1 or TXNIP increases catalytic activity of the redox-sensitive ATG4B cysteine endopeptidase, leading to enhanced LC3B delipidation and failed autophagy. Conversely, REDD1/TXNIP complex expression is sufficient to induce ROS, suppress ATG4B activity and activate autophagy. In Redd1−/− mice, deregulated ATG4B activity and disabled autophagic flux cause accumulation of defective mitochondria, leading to impaired oxidative phosphorylation, muscle ATP depletion and poor exercise capacity. Thus, ROS regulation through REDD1/TXNIP is physiological rheostat controlling stress-induced autophagy. PMID:25916556

  2. A High-Order Immersed Boundary Method for Acoustic Wave Scattering and Low-Mach Number Flow-Induced Sound in Complex Geometries

    PubMed Central

    Seo, Jung Hee; Mittal, Rajat

    2010-01-01

    A new sharp-interface immersed boundary method based approach for the computation of low-Mach number flow-induced sound around complex geometries is described. The underlying approach is based on a hydrodynamic/acoustic splitting technique where the incompressible flow is first computed using a second-order accurate immersed boundary solver. This is followed by the computation of sound using the linearized perturbed compressible equations (LPCE). The primary contribution of the current work is the development of a versatile, high-order accurate immersed boundary method for solving the LPCE in complex domains. This new method applies the boundary condition on the immersed boundary to a high-order by combining the ghost-cell approach with a weighted least-squares error method based on a high-order approximating polynomial. The method is validated for canonical acoustic wave scattering and flow-induced noise problems. Applications of this technique to relatively complex cases of practical interest are also presented. PMID:21318129

  3. DNA binding, photo-induced DNA cleavage and cytotoxicity studies of lomefloxacin and its transition metal complexes

    NASA Astrophysics Data System (ADS)

    Ragheb, Mohamed A.; Eldesouki, Mohamed A.; Mohamed, Mervat S.

    2015-03-01

    This work was focused on a study of the DNA binding and cleavage properties of lomefloxacin (LMF) and its ternary transition metal complexes with glycine. The nature of the binding interactions between compounds and calf thymus DNA (CT-DNA) was studied by electronic absorption spectra, fluorescence spectra and thermal denaturation experiments. The obtained results revealed that LMF and its complexes could interact with CT-DNA via partial/moderate intercalative mode. Furthermore, the DNA cleavage activities of the compounds were investigated by gel electrophoresis. Mechanistic studies of DNA cleavage suggest that singlet oxygen (1O2) is likely to be the cleaving agent via an oxidative pathway, except for Cu(II) complex which proceeds via both oxidative and hydrolytic pathways. Antimicrobial and antitumor activities of the compounds were also studied against some kinds of bacteria, fungi and human cell lines.

  4. Novel monofunctional platinum (II) complex Mono-Pt induces apoptosis-independent autophagic cell death in human ovarian carcinoma cells, distinct from cisplatin

    PubMed Central

    Guo, Wen-Jie; Zhang, Yang-Miao; Zhang, Li; Huang, Bin; Tao, Fei-Fei; Chen, Wei; Guo, Zi-Jian; Xu, Qiang; Sun, Yang

    2013-01-01

    Failure to engage apoptosis appears to be a leading mechanism of resistance to traditional platinum drugs in patients with ovarian cancer. Therefore, an alternative strategy to induce cell death is needed for the chemotherapy of this apoptosis-resistant cancer. Here we report that autophagic cell death, distinct from cisplatin-induced apoptosis, is triggered by a novel monofunctional platinum (II) complex named Mono-Pt in human ovarian carcinoma cells. Mono-Pt-induced cell death has the following features: cytoplasmic vacuolation, caspase-independent, no nuclear fragmentation or chromatin condensation, and no apoptotic bodies. These characteristics integrally indicated that Mono-Pt, rather than cisplatin, initiated a nonapoptotic cell death in Caov-3 ovarian carcinoma cells. Furthermore, incubation of the cells with Mono-Pt but not with cisplatin produced an increasing punctate distribution of microtubule-associated protein 1 light chain 3 (LC3), and an increasing ratio of LC3-II to LC3-I. Mono-Pt also caused the formation of autophagic vacuoles as revealed by monodansylcadaverine staining and transmission electron microscopy. In addition, Mono-Pt-induced cell death was significantly inhibited by the knockdown of either BECN1 or ATG7 gene expression, or by autophagy inhibitors 3-methyladenine, chloroquine and bafilomycin A1. Moreover, the effect of Mono-Pt involved the AKT1-MTOR-RPS6KB1 pathway and MAPK1 (ERK2)/MAPK3 (ERK1) signaling, since the MTOR inhibitor rapamycin increased, while the MAPK1/3 inhibitor U0126 decreased Mono-Pt-induced autophagic cell death. Taken together, our results suggest that Mono-Pt exerts anticancer effect via autophagic cell death in apoptosis-resistant ovarian cancer. These findings lead to increased options for anticancer platinum drugs to induce cell death in cancer. PMID:23580233

  5. Hepatitis B Virus-Induced Parkin-Dependent Recruitment of Linear Ubiquitin Assembly Complex (LUBAC) to Mitochondria and Attenuation of Innate Immunity

    PubMed Central

    Khan, Mohsin; Syed, Gulam Hussain; Kim, Seong-Jun; Siddiqui, Aleem

    2016-01-01

    Hepatitis B virus (HBV) suppresses innate immune signaling to establish persistent infection. Although HBV is a DNA virus, its pre-genomic RNA (pgRNA) can be sensed by RIG-I and activates MAVS to mediate interferon (IFN) λ synthesis. Despite of the activation of RIG-I-MAVS axis by pgRNA, the underlying mechanism explaining how HBV infection fails to induce interferon-αβ (IFN) synthesis remained uncharacterized. We demonstrate that HBV induced parkin is able to recruit the linear ubiquitin assembly complex (LUBAC) to mitochondria and abrogates IFN β synthesis. Parkin interacts with MAVS, accumulates unanchored linear polyubiquitin chains on MAVS via LUBAC, to disrupt MAVS signalosome and attenuate IRF3 activation. This study highlights the novel role of parkin in antiviral signaling which involves LUBAC being recruited to the mitochondria. These results provide avenues of investigations on the role of mitochondrial dynamics in innate immunity. PMID:27348524

  6. DNA break-induced sumoylation is enabled by collaboration between a SUMO ligase and the ssDNA-binding complex RPA

    PubMed Central

    Chung, Inn; Zhao, Xiaolan

    2015-01-01

    Upon genome damage, large-scale protein sumoylation occurs from yeast to humans to promote DNA repair. Currently, the underlying mechanism is largely unknown. Here we show that, upon DNA break induction, the budding yeast SUMO ligase Siz2 collaborates with the ssDNA-binding complex RPA (replication protein A) to induce the sumoylation of recombination factors and confer damage resistance. Both RPA and nuclease-generated ssDNA promote Siz2-mediated sumoylation. Mechanistically, the conserved Siz2 interaction with RPA enables Siz2 localization to damage sites. These findings provide a molecular basis for recruiting SUMO ligases to the vicinity of their substrates to induce sumoylation upon DNA damage. PMID:26253534

  7. Theoretical and Experimental Study on Boron β-Diketonate Complexes with Intense Two-Photon-Induced Fluorescence in Solution and in the Solid State.

    PubMed

    Lanoë, Pierre-Henri; Mettra, Bastien; Liao, Yuan Yuan; Calin, Nathalie; D'Aléo, Anthony; Namikawa, Tomotaka; Kamada, Kenji; Fages, Fréderic; Monnereau, Cyrille; Andraud, Chantal

    2016-07-18

    Three boron diketonate chromophores with extended π-conjugated backbone were prepared and their spectroscopic features were investigated through a combined theoretical/experimental study. It was shown that these complexes, which undergo very large electronic reorganization upon photoexcitation, combine large two-photon absorption cross section with an emission energy and quantum efficiency in solution that is strongly dependent on solvent polarity. The strong positive influence of boron complexation on the magnitude of the two-photon absorption was clearly established, and it was shown that the two-photon absorption properties were dominated by the quadrupolar term. For one of the synthesized compounds, intense one- and two-photon-induced solid-state emission (fluorescence quantum yield of 0.65 with maximum wavelength of 610 nm) was obtained as a result of antiparallel J-aggregate crystal packing. PMID:26990918

  8. Effect of radiation on cytotoxicity, apoptosis and cell cycle arrest of human osteosarcoma MG-63 induced by a ruthenium(II) complex

    NASA Astrophysics Data System (ADS)

    Liu, Si-Hong; Zhao, Jian-Hua; Deng, Kun-Kang; Wu, Yong; Zhu, Jian-Wei; Liu, Qing-Hua; Xu, Hui-Hua; Wu, Hai-Feng; Li, Xin-Yan; Wang, Jian-Wei; Guo, Qi-Feng

    2015-04-01

    Radiation has large influence on the cytotoxicity, apoptosis and cell cycle arrest. The bioactivity of ruthenium(II) complex [Ru(dmb)2(DBHIP)](ClO4)2 (Ru1) (DBHIP = 2-(3,5-dibromo-4-hydroxylphenyl)imidazo[4,5-f][1,10]phenanthroline) was investigated in the absence and presence of radiation. The cytotoxicity of Ru1 against MG-63 cells was evaluated by CCK-8 method. Ru1 shows high cytotoxicity upon radiation. Radiation can enhance the cytotoxicity of Ru1 on MG-63 cells. The apoptosis was studied by Hoechst 33258 staining method and flow cytometry. The reactive oxygen species, mitochondrial membrane potential, cell cycle arrest and western blot analysis were investigated in detail. The complex induces the apoptosis in MG-63 cells through ROS-mediated mitochondrial dysfunction pathway.

  9. Temperature-induced release of crystal water in the Co, Mo and Pt complexes of N,N-diacetatedithiocarbamate. FTIR spectroscopy and quantum chemical study

    NASA Astrophysics Data System (ADS)

    Vojta, Danijela; Višnjevac, Aleksandar; Leka, Zorica; Kosović, Milica; Vazdar, Mario

    2016-01-01

    We describe temperature-induced water release from the complexes of triammonium N,N-diacetatedithiocarbamate (dadtc) with Co(III) (1), Mo(VI) (2) and Pt(II) (3), by the combination of temperature-dependent IR spectroscopy and quantum chemical calculations. Transmission IR spectra show that in the compounds 1 and 2, where water molecules are hydrogen-bonded with complex moieties, water release occurs at about 80 °C. In the compound 3 water most probably exist as non-hydrogen-bonded and remains within the sample above 100 °C. The influence of an inert salt in maintaining the water and consequently bringing up the artefacts in spectra is eliminated by recording the spectra in the internal reflection regime (ATR). Possible interplay of water release from the samples 1 and 2 and samples phase transition is presumed and indicated by the baseline analysis of temperature-dependent transmission IR spectra.

  10. Proteomic identification of a novel hsp90-containing protein-mineral complex which can be induced in cells in response to massive calcium influx.

    PubMed

    Ho, Wen-Hsiung; Lee, Der-Yen; Chang, Geen-Dong

    2012-06-01

    Fetuin-A is known for limiting the expansion and formation of hydroxyapatite crystals from calcium phosphate aggregates in circulation by forming a soluble fetuin-mineral complex. This study was aimed to uncover potential proteins involved in the regulation of calcium phosphate precipitation within cells. We found that a novel protein-mineral complex (PMC) can be generated after introduction of calcium chloride and sodium phosphate into the porcine brain protein extract prepared in Tris-HCl buffer. Selectively enriched proteins in the pellet were confirmed by immunoblotting, including heat shock protein 90 (Hsp90), annexin A5, calreticulin, nucleolin, and other proteins. In addition, purified native Hsp90 directly bound both amorphous calcium phosphate and hydroxyapatite and underwent conformational changes and oligomerization in the presence of excess calcium and phosphate. The morphology of the PMC prepared from Hsp90, calcium, and phosphate was distinctly different from that of hydroxyapatite under transmission electron microscope observation. When cultured SiHa cells were treated with a calcium ionophore or damaged by scratch to induce the massive calcium influx, a complex was formed and observed at discrete sites near the plasma membrane as revealed by antibodies against Hsp90, annexin A5, calreticulin, nucleolin, and other proteins. This complex could also be probed in situ with fetuin-A suggesting the existence of calcium phosphate aggregates in this complex. Inhibition of the complex formation by bisphosphonates hindered cell recovery from A23187 assault. Our results show that following membrane damage amorphous calcium phosphate develops at sites near membrane rupture where saturated calcium phosphate concentration is achieved. As a result, Hsp90 and other proteins are recruited, and the cytosolic PMC is formed. Inhibition of the cytosolic PMC formation may in part contribute to the cellular toxicity and in vivo side effects of bisphosphonates

  11. The kinase LYK5 is a major chitin receptor in Arabidopsis and forms a chitin-induced complex with related kinase CERK1

    DOE PAGESBeta

    Cao, Yangrong; Liang, Yan; Tanaka, Kiwamu; Nguyen, Cuong T.; Jedrzejczak, Robert P.; Joachimiak, Andrzej; Stacey, Gary

    2014-10-23

    Chitin is a fungal microbe-associated molecular pattern recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1. Previous research suggested that AtCERK1 is the major chitin receptor and mediates chitin-induced signaling through homodimerization and phosphorylation. However, the reported chitin binding affinity of AtCERK1 is quite low, suggesting another receptor with high chitin binding affinity might be present. Here, we propose that AtLYK5 is the primary chitin receptor in Arabidopsis. Mutations in AtLYK5 resulted in a significant reduction in chitin response. AtLYK5 shares overlapping function with AtLYK4 and, therefore, Atlyk4/Atlyk5-2 double mutants show a complete loss of chitin response. AtLYK5more » interacts with AtCERK1 in a chitin-dependent manner. Chitin binding to AtLYK5 is indispensable for chitin-induced AtCERK1 phosphorylation. AtLYK5 binds chitin at a much higher affinity than AtCERK1. The data suggest that AtLYK5 is the primary receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant immunity.« less

  12. Immune Complex-Induced, Nitric Oxide-Mediated Vascular Endothelial Cell Death by Phagocytes Is Prevented with Decoy FcγReceptors

    PubMed Central

    Mula, Ramanjaneya V. R.; Machiah, Deepa; Holland, Lauren; Wang, Xinyu; Parihar, Harish; Sharma, Avadhesh C.; Selvaraj, Periasamy; Shashidharamurthy, Rangaiah

    2016-01-01

    Autoimmune vasculitis is an endothelial inflammatory disease that results from the deposition of immune-complexes (ICs) in blood vessels. The interaction between Fcgamma receptors (FcγRs) expressed on inflammatory cells with ICs is known to cause blood vessel damage. Hence, blocking the interaction of ICs and inflammatory cells is essential to prevent the IC-mediated blood vessel damage. Thus we tested if uncoupling the interaction of FcγRs and ICs prevents endothelium damage. Herein, we demonstrate that dimeric FcγR-Igs prevented nitric oxide (NO) mediated apoptosis of human umbilical vein endothelial cells (HUVECs) in an in vitro vasculitis model. Dimeric FcγR-Igs significantly inhibited the IC-induced upregulation of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) release by murine monocytic cell line. However, FcγR-Igs did not affect the exogenously added NO-induced upregulation of pro-apoptotic genes such as Bax (15 fold), Bak (35 fold), cytochrome-C (11 fold) and caspase-3 (30 fold) in HUVECs. In conclusion, these data suggest that IC-induced NO could be one of the major inflammatory mediator promoting blood vessel inflammation and endothelial cell death during IC-mediated vasculitis which can be effectively blocked by dimeric decoy FcγRs. PMID:27101012

  13. The kinase LYK5 is a major chitin receptor in Arabidopsis and forms a chitin-induced complex with related kinase CERK1

    SciTech Connect

    Cao, Yangrong; Liang, Yan; Tanaka, Kiwamu; Nguyen, Cuong T.; Jedrzejczak, Robert P.; Joachimiak, Andrzej; Stacey, Gary

    2014-10-23

    Chitin is a fungal microbe-associated molecular pattern recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1. Previous research suggested that AtCERK1 is the major chitin receptor and mediates chitin-induced signaling through homodimerization and phosphorylation. However, the reported chitin binding affinity of AtCERK1 is quite low, suggesting another receptor with high chitin binding affinity might be present. Here, we propose that AtLYK5 is the primary chitin receptor in Arabidopsis. Mutations in AtLYK5 resulted in a significant reduction in chitin response. AtLYK5 shares overlapping function with AtLYK4 and, therefore, Atlyk4/Atlyk5-2 double mutants show a complete loss of chitin response. AtLYK5 interacts with AtCERK1 in a chitin-dependent manner. Chitin binding to AtLYK5 is indispensable for chitin-induced AtCERK1 phosphorylation. AtLYK5 binds chitin at a much higher affinity than AtCERK1. The data suggest that AtLYK5 is the primary receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant immunity.

  14. COMPLEX FRAMESHIFT MUTATIONS MEDIATED BY PLASMID PKM101: MUTATIONAL MECHANISMS DEDUCED FROM 4-AMINOBIPHENYL-INDUCED MUTATION SPECTRA IN SALMONELLA

    EPA Science Inventory

    We used colony probe hybridization and PCR/DNA sequencing to determine the mutations -aminobiphenyl (4-AB) +S9-induced revertants of the -1 frameshift allele in 2,300 4-aminobiphenyl of the base-substitution allele hisD3052 in strains TA1978, TA1538, and TA98 and were at strains ...

  15. Single-walled carbon nanotube-induced crystallinity on the electropolymeric film of tetraaminophthalocyaninatonickel(II) complex: Impact on the rate of heterogeneous electron transfer

    NASA Astrophysics Data System (ADS)

    Pillay, Jeseelan; Ozoemena, Kenneth I.

    2007-06-01

    We present a fundamental investigation on the impact of single-walled carbon nanotube (SWCNT) on the film structure and redox behaviour of tetraaminophthalocyaninatonickel(II) complex (NiTAPc) electropolymer immobilized on a basal plane pyrolytic graphite electrode (BPPGE). SWCNT induces crystallinity on the NiTAPc electropolymeric film structure and increases its apparent electron transfer rate constant ( kapp). We proved that there is potential advantage of using electrode based on the SWCNT- poly-NiTAPc hybrid for catalytic and sensing applications as it enhances the catalytic current for the detection of nitric oxide more than twice compared to bare BPPGE, BPPGE-SWCNT and other electrodes without SWCNTs.

  16. The role of amino acid-induced mammalian target of rapamycin complex 1(mTORC1) signaling in insulin resistance

    PubMed Central

    Yoon, Mee-Sup; Choi, Cheol Soo

    2016-01-01

    Mammalian target of rapamycin (mTOR) controls cell growth and metabolism in response to nutrients, energy, and growth factors. Recent findings have placed the lysosome at the core of mTOR complex 1 (mTORC1) regulation by amino acids. Two parallel pathways, Rag GTPase-Ragulator and Vps34-phospholipase D1 (PLD1), regulate mTOR activation on the lysosome. This review describes the recent advances in understanding amino acid-induced mTOR signaling with a particular focus on the role of mTOR in insulin resistance. PMID:27534530

  17. The role of amino acid-induced mammalian target of rapamycin complex 1(mTORC1) signaling in insulin resistance.

    PubMed

    Yoon, Mee-Sup; Choi, Cheol Soo

    2016-01-01

    Mammalian target of rapamycin (mTOR) controls cell growth and metabolism in response to nutrients, energy, and growth factors. Recent findings have placed the lysosome at the core of mTOR complex 1 (mTORC1) regulation by amino acids. Two parallel pathways, Rag GTPase-Ragulator and Vps34-phospholipase D1 (PLD1), regulate mTOR activation on the lysosome. This review describes the recent advances in understanding amino acid-induced mTOR signaling with a particular focus on the role of mTOR in insulin resistance. PMID:27534530

  18. Mammalian Target of Rapamycin Inhibitor Induced Complete Remission of a Recurrent Subependymal Giant Cell Astrocytoma in a Patient Without Features of Tuberous Sclerosis Complex.

    PubMed

    Appalla, Deepika; Depalma, Andres; Calderwood, Stanley

    2016-07-01

    The majority of patients with subependymal giant cell astrocytoma (SEGA) have tuberous sclerosis complex (TSC). In such patients, the mammalian target of rapamycin (mTOR) inhibitor everolimus has been shown to induce responses. Isolated SEGA have been reported in patients without clinical or genetic features of TSC. The treatment of these patients with everolimus has not previously been reported. We treated a patient with a recurrent isolated SEGA with an mTOR inhibitor. The patient tolerated therapy well and had a sustained complete remission. MTOR inhibitors may be useful for the treatment of isolated SEGA. Further study is warranted. PMID:26929034

  19. Geometry of a complex formed by double strand break repair proteins at a single DNA end: recruitment of DNA-PKcs induces inward translocation of Ku protein.

    PubMed

    Yoo, S; Dynan, W S

    1999-12-15

    Ku protein and the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) are essential components of the double-strand break repair machinery in higher eukaryotic cells. Ku protein binds to broken DNA ends and recruits DNA-PKcs to form an enzymatically active complex. To characterize the arrangement of proteins in this complex, we developed a set of photocross-linking probes, each with a single free end. We have previously used this approach to characterize the contacts in an initial Ku-DNA complex, and we have now applied the same technology to define the events that occur when Ku recruits DNA-PKcs. The new probes allow the binding of one molecule of Ku protein and one molecule of DNA-PKcs in a defined position and orientation. Photocross-linking reveals that DNA-PKcs makes direct contact with the DNA termini, occupying an approximately 10 bp region proximal to the free end. Characterization of the Ku protein cross-linking pattern in the presence and absence of DNA-PKcs suggests that Ku binds to form an initial complex at the DNA ends, and that recruitment of DNA-PKcs induces an inward translocation of this Ku molecule by about one helical turn. The presence of ATP had no effect on protein-DNA contacts, suggesting that neither DNA-PK-mediated phosphorylation nor a putative Ku helicase activity plays a role in modulating protein conformation under the conditions tested. PMID:10572166

  20. Low Energy Nuclear Transmutation in Condensed Matter Induced by D2 Gas Permeation Through pd Complexes:. Correlation Between Deuterium Flux and Nuclear Products

    NASA Astrophysics Data System (ADS)

    Iwamura, Y.; Itoh, T.; Sakano, M.; Sakai, S.; Kuribayashi, S.

    2005-12-01

    Observations of low energy nuclear reactions induced by D2 gas permeation through Pd complexes (Pd/CaO/Pd) were presented at ICCF-91 and in a paper2 published in the Japanese Journal of Applied Physics. When Cs was added on the surface of a Pd complex, Pr emerged on the surface while Cs decreased after the Pd complex was subjected to D2 gas permeation. When Sr was added to the surface, Mo emerged while the Sr decreased after D2 gas permeation. The isotopic composition of the detected Mo was different from the natural abundance. In this paper, recent progress of our research is described. The detected Pr was confirmed by various methods such as TOF-SIMS, XANES, X-ray Fluorescence Spectrometry and ICP-MS. Analysis of the depth profile of Pr indicated that a very thin surface region up to 100 Å was the active transmutation zone. Many experimental results showed that the quantity of Pr was proportional to the deuterium flux through Pd complex. The cross-section of transmutation of Cs into Pr can be roughly estimated at 1 barn if we consider the deuterium flux as an ultra low energy deuteron beam.

  1. Inducible production of recombinant human Flt3 ectodomain variants in mammalian cells and preliminary crystallographic analysis of Flt3 ligand–receptor complexes

    PubMed Central

    Verstraete, Kenneth; Remmerie, Bert; Elegheert, Jonathan; Lintermans, Beatrice; Haegeman, Guy; Vanhoenacker, Peter; Van Craenenbroeck, Kathleen; Savvides, Savvas N.

    2011-01-01

    The extracellular complex between the haematopoietic receptor Flt3 and its cytokine ligand (FL) is the cornerstone of signalling cascades that are central to early haematopoiesis and the immune system. Here, efficient protocols for the production of two ectodomain variants of human Flt3 receptor, Flt3D1–D5 and Flt3D1–D4, for structural studies are reported based on tetracycline-inducible stable cell lines in HEK293S cells deficient in N-acetylglycosaminyltransferase I (GnTI−/−) that can secrete the target proteins with limited and homogeneous N-­linked glycosylation to milligram amounts. The ensuing preparative purification of Flt3 receptor–ligand complexes yielded monodisperse complex prep­arations that were amenable to crystallization. Crystals of the Flt3D1–D4–FL and Flt3D1–D5–FL complexes diffracted to 4.3 and 7.8 Å resolution, respectively, and exhibited variable diffraction quality even within the same crystal. The resulting data led to the successful structure determination of Flt3D1–D4–FL via a combination of molecular-replacement and density-modification protocols exploiting the noncrystallographic symmetry and high solvent content of the crystals. PMID:21393836

  2. Increased production of mitochondrial superoxide in the spinal cord induces pain behaviors in mice: the effect of mitochondrial electron transport complex inhibitors.

    PubMed

    Kim, Hee Young; Chung, Jin Mo; Chung, Kyungsoon

    2008-12-01

    Scavengers of reactive oxygen species (ROS) have been shown to produce a strong antinociceptive effect on persistent pain, and mitochondria are suggested to be the main source of ROS in the spinal dorsal horn. To explore whether excessive generation of mitochondrial superoxide alone can induce pain, the effect of mitochondrial electron transport complex inhibitors on the development of mechanical hyperalgesia was examined in mice. Intrathecal injection of an electron transport complex inhibitor, antimycin A or rotenone, in normal mice resulted in a slowly developing but long-lasting and dose-dependent mechanical hyperalgesia. The levels of mechanical hyperalgesia after antimycin A, a complex III inhibitor, were higher than that with rotenone, a complex I inhibitor. A large increase of mitochondrial superoxide in the spinal dorsal horn and a strong antinociceptive effect of ROS scavengers, phenyl-N-tert-butylnitrone (PBN) and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) were observed in antimycin A-treated mice. The study indicates that the enhanced production of spinal mitochondrial superoxide alone without nerve injury can produce mechanical hyperalgesia. PMID:18832013

  3. Influence of Equilibration Time in Solution on the Inclusion/Exclusion Topology Ratio of Host-Guest Complexes Probed by Ion Mobility and Collision-Induced Dissociation.

    PubMed

    Carroy, Glenn; Daxhelet, Charlotte; Lemaur, Vincent; De Winter, Julien; De Pauw, Edwin; Cornil, Jérôme; Gerbaux, Pascal

    2016-03-18

    Host-guest complexes are formed by the creation of multiple noncovalent bonds between a large molecule (the host) and smaller molecule(s) or ion(s) (the guest(s)). Ion-mobility separation coupled with mass spectrometry nowadays represents an ideal tool to assess whether the host-guest complexes, when transferred to the gas phase upon electrospray ionization, possess an exclusion or inclusion nature. Nevertheless, the influence of the solution conditions on the nature of the observed gas-phase ions is often not considered. In the specific case of inclusion complexes, kinetic considerations must be taken into account beside thermodynamics; the guest ingression within the host cavity can be characterized by slow kinetics, which makes the complexation reaction kinetically driven on the timescale of the experiment. This is particularly the case for the cucurbituril family of macrocyclic host molecules. Herein, we selected para-phenylenediamine and cucurbit[6]uril as a model system to demonstrate, by means of ion mobility and collision-induced dissociation measurements, that the inclusion/exclusion topology ratio varies as a function of the equilibration time in solution prior to the electrospray process. PMID:26880721

  4. Cytoprotection of pancreatic β-cells and hypoglycemic effect of 2-hydroxypropyl-β-cyclodextrin: sertraline complex in alloxan-induced diabetic rats.

    PubMed

    Buko, Vyacheslav; Zavodnik, Ilya; Lukivskaya, Oxana; Naruta, Elena; Palecz, Bartlomiej; Belica-Pacha, Silwia; Belonovskaya, Elena; Kranc, Robert; Abakumov, Vladimir

    2016-01-25

    Sertraline, a selective inhibitor of serotonin reuptake, is widely used as antidepressant in diabetic patients for improvement of depression and glycemic control. Sertraline is poorly soluble in water, which limits its oral applicability. In this work we tried to improve the pharmaceutical properties of sertraline by complexation with 2-hydroxypropyl-β-cyclodextrin (HPβCD) and evaluated the efficacy of the HPβCD:sertraline complex in prevention of alloxan-induced lesions in rats. The solubility of sertraline increased in the presence of HPβCD and the association constant for sertraline and HPβCD was equal to 4000 ± 1000 M(-1). Two-week treatment of diabetic animals with the HPβCD:sertraline complex improved pancreatic islet morphology and β-cell survival, which, in turn, reduced the severity of diabetes, as evidenced by lowering of blood glucose and glycated hemoglobin contents as well as normalization of serum insulin level and insulin sensitivity (HOMA-IR). The effect of the HPβCD:sertraline complex was strongly expressed in comparison with the antidiabetic effect of both the monopreparations, HPβCD and sertraline. It is suggested that the cyclodextrin derivative increased the pharmacological effect of sertraline, probably due to enhanced drug bioavailability. PMID:26593071

  5. EFC/F-BAR proteins and the N-WASP–WIP complex induce membrane curvature-dependent actin polymerization

    PubMed Central

    Takano, Kazunari; Toyooka, Kiminori; Suetsugu, Shiro

    2008-01-01

    Extended Fer-CIP4 homology (EFC)/FCH-BAR (F-BAR) domains generate and bind to tubular membrane structures of defined diameters that are involved in the formation and fission of endocytotic vesicles. Formin-binding protein 17 (FBP17) and Toca-1 contain EFC/F-BAR domains and bind to neural Wiskott–Aldrich syndrome protein (N-WASP), which links phosphatidylinositol (4,5)-bisphosphate (PIP2) and the Rho family GTPase Cdc42 to the Arp2/3 complex. The N-WASP–WASP-interacting protein (WIP) complex, a predominant form of N-WASP in cells, is known to be activated by Toca-1 and Cdc42. Here, we show that N-WASP–WIP complex-mediated actin polymerization is activated by phosphatidylserine-containing membranes depending on membrane curvature in the presence of Toca-1 or FBP17 and in the absence of Cdc42 and PIP2. Cdc42 further promoted the activation of actin polymerization by N-WASP–WIP. Toca-1 or FBP17 recruited N-WASP–WIP to the membrane. Conserved acidic residues near the SH3 domain of Toca-1 and FBP17 positioned the N-WASP–WIP to be spatially close to the membrane for activation of actin polymerization. Therefore, curvature-dependent actin polymerization is stimulated by spatially appropriate interactions of EFC/F-BAR proteins and the N-WASP–WIP complex with the membrane. PMID:18923421

  6. Molecular Spin Crossover in Slow Motion: Light-Induced Spin-State Transitions in Trigonal Prismatic Iron(II) Complexes.

    PubMed

    Stock, Philipp; Deck, Eva; Hohnstein, Silvia; Korzekwa, Jana; Meyer, Karsten; Heinemann, Frank W; Breher, Frank; Hörner, Gerald

    2016-06-01

    A straightforward access is provided to iron(II) complexes showing exceedingly slow spin-state interconversion by utilizing trigonal-prismatic directing ligands (L(n)) of the extended-tripod type. A detailed analysis of the interrelations between complex structure (X-ray diffraction, density functional theory) and electronic character (SQUID magnetometry, Mössbauer spectroscopy, UV/vis spectroscopy) of the iron(II) center in mononuclear complexes [FeL(n)] reveals spin crossover to occur along a coupled breathing/torsion reaction coordinate, shuttling the complex between the octahedral low-spin state and the trigonal-prismatic high-spin state along Bailar's trigonal twist pathway. We associate both the long spin-state lifetimes in the millisecond domain close to room temperature and the substantial barriers against thermal scrambling (Ea ≈ 33 kJ mol(-1), from Arrhenius analysis) with stereochemical constraints. In particular, the topology of the κ(6)N ligands controls the temporary and structural dynamics during spin crossover. PMID:27159332

  7. Akirin2 is critical for inducing inflammatory genes by bridging IκB-ζ and the SWI/SNF complex

    PubMed Central

    Tartey, Sarang; Matsushita, Kazufumi; Vandenbon, Alexis; Ori, Daisuke; Imamura, Tomoko; Mino, Takashi; Standley, Daron M; Hoffmann, Jules A; Reichhart, Jean-Marc; Akira, Shizuo; Takeuchi, Osamu

    2014-01-01

    Transcription of inflammatory genes in innate immune cells is coordinately regulated by transcription factors, including NF-κB, and chromatin modifiers. However, it remains unclear how microbial sensing initiates chromatin remodeling. Here, we show that Akirin2, an evolutionarily conserved nuclear protein, bridges NF-κB and the chromatin remodeling SWI/SNF complex by interacting with BRG1-Associated Factor 60 (BAF60) proteins as well as IκB-ζ, which forms a complex with the NF-κB p50 subunit. These interactions are essential for Toll-like receptor-, RIG-I-, and Listeria-mediated expression of proinflammatory genes including Il6 and Il12b in macrophages. Consistently, effective clearance of Listeria infection required Akirin2. Furthermore, Akirin2 and IκB-ζ recruitment to the Il6 promoter depend upon the presence of IκB-ζ and Akirin2, respectively, for regulation of chromatin remodeling. BAF60 proteins were also essential for the induction of Il6 in response to LPS stimulation. Collectively, the IκB-ζ–Akirin2–BAF60 complex physically links the NF-κB and SWI/SNF complexes in innate immune cell activation. By recruiting SWI/SNF chromatin remodellers to IκB-ζ, transcriptional coactivator for NF-κB, the conserved nuclear protein Akirin2 stimulates pro-inflammatory gene promoters in mouse macrophages during innate immune responses to viral or bacterial infection. PMID:25107474

  8. Akirin2 is critical for inducing inflammatory genes by bridging IκB-ζ and the SWI/SNF complex.

    PubMed

    Tartey, Sarang; Matsushita, Kazufumi; Vandenbon, Alexis; Ori, Daisuke; Imamura, Tomoko; Mino, Takashi; Standley, Daron M; Hoffmann, Jules A; Reichhart, Jean-Marc; Akira, Shizuo; Takeuchi, Osamu

    2014-10-16

    Transcription of inflammatory genes in innate immune cells is coordinately regulated by transcription factors, including NF-κB, and chromatin modifiers. However, it remains unclear how microbial sensing initiates chromatin remodeling. Here, we show that Akirin2, an evolutionarily conserved nuclear protein, bridges NF-κB and the chromatin remodeling SWI/SNF complex by interacting with BRG1-Associated Factor 60 (BAF60) proteins as well as IκB-ζ, which forms a complex with the NF-κB p50 subunit. These interactions are essential for Toll-like receptor-, RIG-I-, and Listeria-mediated expression of proinflammatory genes including Il6 and Il12b in macrophages. Consistently, effective clearance of Listeria infection required Akirin2. Furthermore, Akirin2 and IκB-ζ recruitment to the Il6 promoter depend upon the presence of IκB-ζ and Akirin2, respectively, for regulation of chromatin remodeling. BAF60 proteins were also essential for the induction of Il6 in response to LPS stimulation. Collectively, the IκB-ζ-Akirin2-BAF60 complex physically links the NF-κB and SWI/SNF complexes in innate immune cell activation. By recruiting SWI/SNF chromatin remodellers to IκB-ζ, transcriptional coactivator for NF-κB, the conserved nuclear protein Akirin2 stimulates pro-inflammatory gene promoters in mouse macrophages during innate immune responses to viral or bacterial infection. PMID:25107474

  9. Kinetic studies on the oxidation of oxyhemoglobin by biologically active iron thiosemicarbazone complexes: relevance to iron-chelator-induced methemoglobinemia.

    PubMed

    Basha, Maram T; Rodríguez, Carlos; Richardson, Des R; Martínez, Manuel; Bernhardt, Paul V

    2014-03-01

    The oxidation of oxyhemoglobin to methemoglobin has been found to be facilitated by low molecular weight iron(III) thiosemicarbazone complexes. This deleterious reaction, which produces hemoglobin protein units unable to bind dioxygen and occurs during the administration of iron chelators such as the well-known 3-aminopyridine-2-pyridinecarbaldehyde thiosemicarbazone (3-AP; Triapine), has been observed in the reaction with Fe(III) complexes of some members of the 3-AP structurally-related thiosemicarbazone ligands derived from di-2-pyridyl ketone (HDpxxT series). We have studied the kinetics of this oxidation reaction in vitro using human hemoglobin and found that the reaction proceeds with two distinct time-resolved steps. These have been associated with sequential oxidation of the two different oxyheme cofactors in the α and β protein chains. Unexpected steric and hydrogen-bonding effects on the Fe(III) complexes appear to be the responsible for the observed differences in the reaction rate across the series of HDpxxT ligand complexes used in this study. PMID:24317633

  10. MOLECULAR ANALYSIS OF MUTATIONS INDUCED AT THE HISD3052 ALLELE OF SALMONELLA BY SINGLE CHEMICALS AND COMPLEX MIXTURES

    EPA Science Inventory

    More single chemicals and complex environmental mixtures have been evaluated for mutagenicity at the hisD3052 allele of Salmonella, primarily in strain TA98, than in any other mutation assay. he development of colony probe hybridization procedures and the application of the polym...

  11. Ligand-induced formation of a transient tryptophan synthase complex with αββ subunit stoichiometry.

    PubMed

    Ehrmann, Alexander; Richter, Klaus; Busch, Florian; Reimann, Julia; Albers, Sonja-Verena; Sterner, Reinhard

    2010-12-28

    The prototypical tryptophan synthases form a stable heterotetrameric αββα complex in which the constituting TrpA and TrpB1 subunits activate each other in a bidirectional manner. The hyperthermophilic archaeon Sulfolobus solfataricus does not contain a TrpB1 protein but instead two members of the phylogenetically distinct family of TrpB2 proteins, which are encoded within (sTrpB2i) and outside (sTrpB2a) the tryptophan operon. It has previously been shown that sTrpB2a does not functionally or structurally interact with sTrpA, whereas sTrpB2i substantially activates sTrpA in a unidirectional manner. However, in the absence of catalysis, no physical complex between sTrpB2i and sTrpA could be detected. In order to elucidate the structural requirements for complex formation, we have analyzed the interaction between sTrpA (α-monomer) and sTrpB2i (ββ-dimer) by means of spectroscopy, analytical gel filtration, and analytical ultracentrifugation, as well as isothermal titration calorimetry. In the presence of the TrpA ligand glycerol 3-phosphate (GP) and the TrpB substrate l-serine, sTrpA and sTrpB2i formed a physical complex with a thermodynamic dissociation constant of about 1 μM, indicating that the affinity between the α- and ββ-subunits is weaker by at least 1 order of magnitude than the affinity between the corresponding subunits of prototypical tryptophan synthases. The observed stoichiometry of the complex was 1 subunit of sTrpA per 2 subunits of sTrpB2i, which corresponds to a αββ quaternary structure and testifies to a strong negative cooperativity for the binding of the α-monomers to the ββ-dimer. The analysis of the interaction between sTrpB2i and sTrpA in the presence of several substrate, transition state, and product analogues suggests that the αββ complex remains stable during the whole catalytic cycle and disintegrates into α- and ββ-subunits upon the release of the reaction product tryptophan. The formation of a transient tryptophan

  12. The THO/TREX Complex Active in miRNA Biogenesis Negatively Regulates Root-Associated Acid Phosphatase Activity Induced by Phosphate Starvation1[OPEN

    PubMed Central

    Tao, Sibo; Zhang, Ye; Wang, Xiaoyue; Xu, Le; Fang, Xiaofeng; Lu, Zhi John

    2016-01-01

    Induction and secretion of acid phosphatases (APases) is an adaptive response that plants use to cope with P (Pi) deficiency in their environment. The molecular mechanism that regulates this response, however, is poorly understood. In this work, we identified an Arabidopsis (Arabidopsis thaliana) mutant, hps8, which exhibits enhanced APase activity on its root surface (also called root-associated APase activity). Our molecular and genetic analyses indicate that this altered Pi response results from a mutation in the AtTHO1 gene that encodes a subunit of the THO/TREX protein complex. The mutation in another subunit of this complex, AtTHO3, also enhances root-associated APase activity under Pi starvation. In Arabidopsis, the THO/TREX complex functions in mRNA export and miRNA biogenesis. When treated with Ag+, an inhibitor of ethylene perception, the enhanced root-associated APase activity in hps8 is largely reversed. hpr1-5 is another mutant allele of AtTHO1 and shows similar phenotypes as hps8. ein2 is completely insensitive to ethylene. In the hpr1-5ein2 double mutant, the enhanced root-associated APase activity is also greatly suppressed. These results indicate that the THO/TREX complex in Arabidopsis negatively regulates root-associated APase activity induced by Pi starvation by inhibiting ethylene signaling. In addition, we found that the miRNA399-PHO2 pathway is also involved in the regulation of root-associated APase activity induced by Pi starvation. These results provide insight into the molecular mechanism underlying the adaptive response of plants to Pi starvation. PMID:27329222

  13. The light-induced transcriptome of the zebrafish pineal gland reveals complex regulation of the circadian clockwork by light

    PubMed Central

    Ben-Moshe, Zohar; Alon, Shahar; Mracek, Philipp; Faigenbloom, Lior; Tovin, Adi; Vatine, Gad D.; Eisenberg, Eli; Foulkes, Nicholas S.; Gothilf, Yoav

    2014-01-01

    Light constitutes a primary signal whereby endogenous circadian clocks are synchronized (‘entrained’) with the day/night cycle. The molecular mechanisms underlying this vital process are known to require gene activation, yet are incompletely understood. Here, the light-induced transcriptome in the zebrafish central clock organ, the pineal gland, was characterized by messenger RNA (mRNA) sequencing (mRNA-seq) and microarray analyses, resulting in the identification of multiple light-induced mRNAs. Interestingly, a considerable portion of the molecular clock (14 genes) is light-induced in the pineal gland. Four of these genes, encoding the transcription factors dec1, reverbb1, e4bp4-5 and e4bp4-6, differentially affected clock- and light-regulated promoter activation, suggesting that light-input is conveyed to the core clock machinery via diverse mechanisms. Moreover, we show that dec1, as well as the core clock gene per2, is essential for light-entrainment of rhythmic locomotor activity in zebrafish larvae. Additionally, we used microRNA (miRNA) sequencing (miR-seq) and identified pineal-enhanced and light-induced miRNAs. One such miRNA, miR-183, is shown to downregulate e4bp4-6 mRNA through a 3′UTR target site, and importantly, to regulate the rhythmic mRNA levels of aanat2, the key enzyme in melatonin synthesis. Together, this genome-wide approach and functional characterization of light-induced factors indicate a multi-level regulation of the circadian clockwork by light. PMID:24423866

  14. The light-induced transcriptome of the zebrafish pineal gland reveals complex regulation of the circadian clockwork by light.

    PubMed

    Ben-Moshe, Zohar; Alon, Shahar; Mracek, Philipp; Faigenbloom, Lior; Tovin, Adi; Vatine, Gad D; Eisenberg, Eli; Foulkes, Nicholas S; Gothilf, Yoav

    2014-04-01

    Light constitutes a primary signal whereby endogenous circadian clocks are synchronized ('entrained') with the day/night cycle. The molecular mechanisms underlying this vital process are known to require gene activation, yet are incompletely understood. Here, the light-induced transcriptome in the zebrafish central clock organ, the pineal gland, was characterized by messenger RNA (mRNA) sequencing (mRNA-seq) and microarray analyses, resulting in the identification of multiple light-induced mRNAs. Interestingly, a considerable portion of the molecular clock (14 genes) is light-induced in the pineal gland. Four of these genes, encoding the transcription factors dec1, reverbb1, e4bp4-5 and e4bp4-6, differentially affected clock- and light-regulated promoter activation, suggesting that light-input is conveyed to the core clock machinery via diverse mechanisms. Moreover, we show that dec1, as well as the core clock gene per2, is essential for light-entrainment of rhythmic locomotor activity in zebrafish larvae. Additionally, we used microRNA (miRNA) sequencing (miR-seq) and identified pineal-enhanced and light-induced miRNAs. One such miRNA, miR-183, is shown to downregulate e4bp4-6 mRNA through a 3'UTR target site, and importantly, to regulate the rhythmic mRNA levels of aanat2, the key enzyme in melatonin synthesis. Together, this genome-wide approach and functional characterization of light-induced factors indicate a multi-level regulation of the circadian clockwork by light. PMID:24423866

  15. Prenatal exposure to sodium phenytoin in rats induces complex maze learning deficits comparable to those induced by exposure to phenytoin acid at half the dose.

    PubMed

    Vorhees, C V; Acuff-Smith, K D; Schilling, M A; Moran, M S

    1995-01-01

    Gravid Sprague-Dawley CD (VAF) rats were administered sodium phenytoin suspended in corn oil by gavage once per day on embryonic days 7-18 at a dose of 100 mg/kg. Controls were administered corn oil alone by gavage on E7-18. Litters were randomly culled to 10. Offspring were regularly weighted, mortality noted, and males checked for preputial separation. At approximately 50 days of age offspring were evaluated in a straight water-filled channel for swimming proficiency and motivation to escape. Following this, rats were tested in the Cincinnati multiple T-water maze and scored for errors, latency to find the goal, and presence of phenytoin-induced abnormal circling behavior while swimming. Sodium phenytoin-exposed dams gained weight normally and delivered normally. Offspring mortality in the sodium phenytoin group was not increased above controls. No treatment effects on preputial separation or offspring growth were observed. No differences between groups in swimming proficiency in straight channel performance were obtained. In the Cincinnati maze, phenytoin offspring committed significantly more errors and had longer latencies to find the goal than controls. Among the phenytoin offspring, those exhibiting abnormal circling committed more errors than noncircling animals. When compared to previous data using the same maze and test protocol, it was found that 100 mg/kg of sodium phenytoin induced performance deficits similar to those induced by a dose of 200 mg/kg of phenytoin acid. Accordingly, the present data help explain why other investigators have reported sodium phenytoin to be more developmentally neurotoxic than phenytoin acid. Because the prenatal neurotoxic effects seen with the salt of phenytoin occur at lower doses, it suggests that phenytoin is more developmentally neurotoxic than previously believed. PMID:8747744

  16. GR SUMOylation and formation of an SUMO-SMRT/NCoR1-HDAC3 repressing complex is mandatory for GC-induced IR nGRE-mediated transrepression.

    PubMed

    Hua, Guoqiang; Paulen, Laetitia; Chambon, Pierre

    2016-02-01

    Unique among the nuclear receptor superfamily, the glucocorticoid (GC) receptor (GR) can exert three distinct transcriptional regulatory functions on binding of a single natural (cortisol in human and corticosterone in mice) and synthetic [e.g., dexamethasone (Dex)] hormone. The molecular mechanisms underlying GC-induced positive GC response element [(+)GRE]-mediated activation of transcription are partially understood. In contrast, these mechanisms remain elusive for GC-induced evolutionary conserved inverted repeated negative GC response element (IR nGRE)-mediated direct transrepression and for tethered indirect transrepression that is mediated by DNA-bound NF-κB/activator protein 1 (AP1)/STAT3 activators and instrumental in GC-induced anti-inflammatory activity. We demonstrate here that SUMOylation of lysine K293 (mouse K310) located within an evolutionary conserved sequence in the human GR N-terminal domain allows the formation of a GR-small ubiquitin-related modifiers (SUMOs)-NCoR1/SMRT-HDAC3 repressing complex mandatory for GC-induced IR nGRE-mediated direct repression in vitro, but does not affect transactivation. Importantly, these results were validated in vivo: in K310R mutant mice and in mice ablated selectively for nuclear receptor corepressor 1 (NCoR1)/silencing mediator for retinoid or thyroid-hormone receptors (SMRT) corepressors in skin keratinocytes, Dex-induced direct repression and the formation of repressing complexes on IR nGREs were impaired, whereas transactivation was unaffected. In mice selectively ablated for histone deacetylase 3 (HDAC3) in skin keratinocytes, GC-induced direct repression, but not bindings of GR and of corepressors NCoR1/SMRT, was abolished, indicating that HDAC3 is instrumental in IR nGRE-mediated repression. Moreover, we demonstrate that the binding of HDAC3 to IR nGREs in vivo is mediated through interaction with SMRT/NCoR1. We also show that the GR ligand binding domain (LBD) is not required for SMRT

  17. A role for Mediator complex subunit MED13L in Rb/E2F-induced growth arrest

    PubMed Central

    Angus, Steven P.; Nevins, Joseph R.

    2013-01-01

    The Rb/E2F pathway is deregulated in virtually all human tumors. It is clear that, in addition to Rb itself, essential co-factors required for transcriptional repression and silencing of E2F target genes are mutated or lost in cancer. To identify novel co-factors required for Rb/E2F-mediated inhibition of cell proliferation, we performed a genome-wide shRNA screen. In addition to several known Rb co-factors, the screen identified components of the Mediator complex, a large multiprotein coactivator required for RNA polymerase II transcription. We show that the Mediator complex subunit MED13L is required for Rb/E2F control of cell growth, the complete repression of cell cycle target genes, and cell cycle inhibition. PMID:22249253

  18. Antineoplastic copper coordinated complexes (Casiopeinas) uncouple oxidative phosphorylation and induce mitochondrial permeability transition in cardiac mitochondria and cardiomyocytes.

    PubMed

    Silva-Platas, Christian; Guerrero-Beltrán, Carlos Enrique; Carrancá, Mariana; Castillo, Elena Cristina; Bernal-Ramírez, Judith; Oropeza-Almazán, Yuriana; González, Lorena N; Rojo, Rocío; Martínez, Luis Enrique; Valiente-Banuet, Juan; Ruiz-Azuara, Lena; Bravo-Gómez, María Elena; García, Noemí; Carvajal, Karla; García-Rivas, Gerardo

    2016-02-01

    Copper-based drugs, Casiopeinas (Cas), exhibit antiproliferative and antineoplastic activities in vitro and in vivo, respectively. Unfortunately, the clinical use of these novel chemotherapeutics could be limited by the development of dose-dependent cardiotoxicity. In addition, the molecular mechanisms underlying Cas cardiotoxicity and anticancer activity are not completely understood. Here, we explore the potential impact of Cas on the cardiac mitochondria energetics as the molecular mechanisms underlying Cas-induced cardiotoxicity. To explore the properties on mitochondrial metabolism, we determined Cas effects on respiration, membrane potential, membrane permeability, and redox state in isolated cardiac mitochondria. The effect of Cas on the mitochondrial membrane potential (Δψm) was also evaluated in isolated cardiomyocytes by confocal microscopy and flow cytometry. Cas IIIEa, IIgly, and IIIia predominately inhibited maximal NADH- and succinate-linked mitochondrial respiration, increased the state-4 respiration rate and reduced membrane potential, suggesting that Cas also act as mitochondrial uncouplers. Interestingly, cyclosporine A inhibited Cas-induced mitochondrial depolarization, suggesting the involvement of mitochondrial permeability transition pore (mPTP). Similarly to isolated mitochondria, in isolated cardiomyocytes, Cas treatment decreased the Δψm and cyclosporine A treatment prevented mitochondrial depolarization. The production of H2O2 increased in Cas-treated mitochondria, which might also increase the oxidation of mitochondrial proteins such as adenine nucleotide translocase. In accordance, an antioxidant scavenger (Tiron) significantly diminished Cas IIIia mitochondrial depolarization. Cas induces a prominent loss of membrane potential, associated with alterations in redox state, which increases mPTP opening, potentially due to thiol-dependent modifications of the pore, suggesting that direct or indirect inhibition of mPTP opening might

  19. Ferrocenyl-L-amino acid copper(II) complexes showing remarkable photo-induced anticancer activity in visible light.

    PubMed

    Goswami, Tridib K; Gadadhar, Sudarshan; Balaji, Babu; Gole, Bappaditya; Karande, Anjali A; Chakravarty, Akhil R

    2014-08-21

    Ferrocene-conjugated copper(ii) complexes [Cu(Fc-aa)(aip)](ClO4) () and [Cu(Fc-aa)(pyip)](ClO4) () of l-amino acid reduced Schiff bases (Fc-aa), 2-(9-anthryl)-1H-imidazo[4,5-f][1,10]phenanthroline (aip) and 2-(1-pyrenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (pyip), where Fc-aa is ferrocenylmethyl-l-tyrosine (Fc-Tyr in , ), ferrocenylmethyl-l-tryptophan (Fc-Trp in , ) and ferrocenylmethyl-l-methionine (Fc-Met in , ), were prepared and characterized, and their photocytotoxicity was studied (Fc = ferrocenyl moiety). Phenyl analogues, viz. [Cu(Ph-Met)(aip)](ClO4) () and [Cu(Ph-Met)(pyip)](ClO4) (), were prepared and used as control compounds. The bis-imidazophenanthroline copper(ii) complexes, viz. [Cu(aip)2(NO3)](NO3) () and [Cu(pyip)2(NO3)](NO3) (), were also prepared and used as controls. Complexes having a redox inactive cooper(ii) center showed the Fc(+)-Fc redox couple at ∼0.5 V vs. SCE in DMF-0.1 mol [Bu(n)4N](ClO4). The copper(ii)-based d-d band was observed near 600 nm in DMF-Tris-HCl buffer (1 : 1 v/v). The ferrocenyl complexes showed low dark toxicity, but remarkably high photocytotoxicity in human cervical HeLa and human breast adenocarcinoma MCF-7 cancer cells giving an excellent photo-dynamic effect while their phenyl analogues were inactive. The photo-exposure caused significant morphological changes in the cancer cells when compared to the non-irradiated ones. The photophysical processes were rationalized from the theoretical studies. Fluorescence microscopic images showed and localizing predominantly in the endoplasmic reticulum (ER) of the cancer cells, thus minimizing any undesirable effects involving nuclear DNA. PMID:24971754

  20. Protective activity of Cynara scolymus L. leaf extract against chemically induced complex genomic alterations in CHO cells.

    PubMed

    Jacociunas, Laura Vicedo; de Andrade, Heloisa Helena Rodrigues; Lehmann, Mauricio; Pedersini, Larissa Wölfle; Ferraz, Alexandre de Barros Falcão; da Silva, Juliana; Dihl, Rafael Rodrigues

    2013-09-15

    Cynara scolymus L., popularly known as artichoke, has been widely used in traditional medicine as an herbal medicament for therapeutic purposes. The study aimed at assessing the protective activity of Cynara scolymus leaf extract (LE) against DNA lesions induced by the alkylating agent ethylmethnesulphonate (EMS) in Chinese hamster ovary cells (CHO). The ability of C. scolymus L. LE to modulate the mutagenicity of EMS was examined using the cytokinesis block micronucleus (CBMN) cytome assay in three antigenotoxic protocols, pre- post- and simultaneous treatments. In the pre-treatment, C. scolymus L. LE reduced the frequencies of MNi and NBUDs induced by EMS in the lower concentration. In contrast, at the highest concentration (5 mg/ml) artichoke enhanced the frequency of MNi, potentiating EMS genotoxicity. In the simultaneous treatment only the induction of MNi was repressed by the exposure of cells to C. scolymus L. LE. No modification in genotoxicity was observed in LE post-treatment. The results obtained in this study suggest that lower concentrations of artichoke prevent chemically induced genomic damage in mammalian cells. In this context, the protective activity of C. scolymus L. could be associated to its constitutive antioxidants compounds. PMID:23830816

  1. Resveratrol Induces a Mitochondrial Complex I-dependent Increase in NADH Oxidation Responsible for Sirtuin Activation in Liver Cells*

    PubMed Central

    Desquiret-Dumas, Valérie; Gueguen, Naïg; Leman, Géraldine; Baron, Stéphanie; Nivet-Antoine, Valérie; Chupin, Stéphanie; Chevrollier, Arnaud; Vessières, Emilie; Ayer, Audrey; Ferré, Marc; Bonneau, Dominique; Henrion, Daniel; Reynier, Pascal; Procaccio, Vincent

    2013-01-01

    Resveratrol (RSV) has been shown to be involved in the regulation of energetic metabolism, generating increasing interest in therapeutic use. SIRT1 has been described as the main target of RSV. However, recent reports have challenged the hypothesis of its direct activation by RSV, and the signaling pathways remain elusive. Here, the effects of RSV on mitochondrial metabolism are detailed both in vivo and in vitro using murine and cellular models and isolated enzymes. We demonstrate that low RSV doses (1–5 μm) directly stimulate NADH dehydrogenases and, more specifically, mitochondrial complex I activity (EC50 ∼1 μm). In HepG2 cells, this complex I activation increases the mitochondrial NAD+/NADH ratio. This higher NAD+ level initiates a SIRT3-dependent increase in the mitochondrial substrate supply pathways (i.e. the tricarboxylic acid cycle and fatty acid oxidation). This effect is also seen in liver mitochondria of RSV-fed animals (50 mg/kg/day). We conclude that the increase in NADH oxidation by complex I is a crucial event for SIRT3 activation by RSV. Our results open up new perspectives in the understanding of the RSV signaling pathway and highlight the critical importance of RSV doses used for future clinical trials. PMID:24178296

  2. Excess Electron Attachment Induces Barrier-Free Proton Transfer in Anionic Complexes of Thymine and Uracil with Formic Acid

    SciTech Connect

    Haranczyk, Maciej; Dabkowska, Iwona; Rak, Janusz; Gutowski, Maciej S.; Nilles, J.M.; Stokes, Sarah; Radisic, Dunja; Bowen, Kit H.

    2004-06-03

    The anionic complexes of formic acid with uracil and thymine reveal broad features in photoelectron spectroscopy (PES) experiments with maxima at 1.7 and 1.1 eV, respectively. The results of quantum chemical calculations suggest that electron vertical detachment energies (VDE) of 1.6-1.9 eV correspond to anionic structures in which a proton has been transferred from the carboxylic group of the formic acid to the O8 atom of uracil or thymine. Smaller values of VDE (0.8 to 1.3 eV) correspond to chemically untransformed complexes, in which anionic uracil or thymine interacts through two hydrogen bonds with the carboxylic group of the intact formic acid. The recorded spectra and the results of quantum chemical calculations suggest that both nucleic acid bases undergo barrier-free proton transfer in anionic complexes with formic acid. The difference in experimental spectra of UF- and TF- provides an indication that the methyl group of thymine could make a difference in the intermolecular proton transfer.

  3. On the relationship between block of the cardiac Na+ channel and drug-induced prolongation of the QRS complex

    PubMed Central

    Harmer, AR; Valentin, J-P; Pollard, CE

    2011-01-01

    BACKGROUND AND PURPOSE Inhibition of the human cardiac Na+ channel (hNav1.5) can prolong the QRS complex and has been associated with increased mortality in patients with underlying cardiovascular disease. The safety implications of blocking hNav1.5 channels suggest the need to test for this activity early in drug discovery in order to design out any potential liability. However, interpretation of hNav1.5 blocking potency requires knowledge of how hNav1.5 block translates into prolongation of the QRS complex. EXPERIMENTAL APPROACH We tested Class I anti-arrhythmics, other known QRS prolonging drugs and drugs not reported to prolong the QRS complex. Their block of hNav1.5 channels (as IC50 values) was measured in an automated electrophysiology-based assay. These IC50 values were compared with published reports of the corresponding unbound (free) plasma concentrations attained during clinical use (fCmax) to provide an IC50 : fCmax ratio. KEY RESULTS For 42 Class I anti-arrhythmics and other QRS prolonging drugs, 67% had IC50 : fCmax ratios <30. For 55 non-QRS prolonging drugs tested, 72% had ratios >100. Finally, we determined the relationship between the IC50 value and the free drug concentration associated with prolongation of the QRS complex in humans. For 37 drugs, QRS complex prolongation was observed at free plasma concentrations that were about 15-fold lower than the corresponding IC50 at hNav1.5 channels. CONCLUSIONS AND IMPLICATIONS A margin of 30- to 100-fold between hNav1.5 IC50 and fCmax appears to confer an acceptable degree of safety from QRS prolongation. QRS prolongation occurs on average at free plasma levels 15-fold below the IC50 at hNav1.5 channels. LINKED ARTICLE This article is commented on by Gintant et al., pp. 254–259 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2011.01433.x PMID:21480866

  4. Exploring the heat-induced structural changes of β-lactoglobulin -linoleic acid complex by fluorescence spectroscopy and molecular modeling techniques.

    PubMed

    Simion Ciuciu, Ana-Maria; Aprodu, Iuliana; Dumitrașcu, Loredana; Bahrim, Gabriela Elena; Alexe, Petru; Stănciuc, Nicoleta

    2015-12-01

    Linoleic acid (LA) is the precursor of bioactive oxidized linoleic acid metabolites and arachidonic acid, therefore is essential for human growth and plays an important role in good health in general. Because of the low water solubility and sensitivity to oxidation, new ways of LA delivery without compromising the sensory attributes of the enriched products are to be identified. The major whey protein, β-lactoglobulin (β-Lg), is a natural carrier for hydrophobic molecules. The thermal induced changes of the β-Lg-LA complex were investigated in the temperature range from 25 to 85 °C using fluorescence spectroscopy techniques in combination with molecular modeling study and the results were compared with those obtained for β-Lg. Experimental results indicated that, regardless of LA binding, the polypeptide chain rearrangements at temperatures higher than 75 °C lead to higher exposure of hydrophobic residues causing the increase of fluorescence intensity. Phase diagram indicated an all or none transition between two conformations. The LA surface involved in the interaction with β-Lg was about 497 Ǻ(2), indicating a good affinity between those two components even at high temperatures. Results obtained in this study provide important details about heat-induced changes in the conformation of β-Lg-LA complex. The thermal treatment at high temperature does not affect the LA binding and carrier functions of β-Lg. PMID:26604382

  5. X-Ray Diffraction and Mössbauer Spectroscopy Studies of Pressure-Induced Phase Transitions in a Mixed-Valence Trinuclear Iron Complex.

    PubMed

    Madsen, Solveig R; Gunnlaugsson, Haraldur P; Moggach, Stephen A; Eikeland, Espen; Wu, Lai-Chin; Leupold, Olaf; Overgaard, Jacob; Iversen, Bo B

    2016-07-01

    The mixed-valence complex Fe3 O(cyanoacetate)6 (H2 O)3 (1) has been studied by single-crystal X-ray diffraction analysis at pressures up to 5.3(1) GPa and by (synchrotron) Mössbauer spectroscopy at pressures up to 8(1) GPa. Crystal structure refinements were possible up to 4.0(1) GPa. In this pressure range, 1 undergoes two pressure-induced phase transitions. The first phase transition at around 3 GPa is isosymmetric and involves a 60° rotation of 50 % of the cyanoacetate ligands. The second phase transition at around 4 GPa reduces the symmetry from rhombohedral to triclinic. Mössbauer spectra show that the complex becomes partially valence-trapped after the second phase transition. This sluggish pressure-induced valence-trapping is in contrast to the very abrupt valence-trapping observed when compound 1 is cooled from 130 to 120 K at ambient pressure. PMID:27245642

  6. Ruthenium Polypyridyl Complex Inhibits Growth and Metastasis of Breast Cancer Cells by Suppressing FAK signaling with Enhancement of TRAIL-induced Apoptosis

    PubMed Central

    Cao, Wenqiang; Zheng, Wenjie; Chen, Tianfeng

    2015-01-01

    Ruthenium-based complexes have emerged as promising antitumor and antimetastatic agents during the past decades. However, the limited understanding of the antimetastatic mechanisms of these agents is a roadblock to their clinical application. Herein, we reported that, RuPOP, a ruthenium polypyridyl complex with potent antitumor activity, was able to effectively inhibit growth and metastasis of MDA-MB-231 cells and synergistically enhance TRAIL-induced apoptosis. The selective intracellular uptake and cytotoxic effect of RuPOP was found associated with transferring receptor (TfR)-mediated endocytosis. Further investigation on intracellular mechanisms reveled that RuPOP notably suppressed FAK-mediated ERK and Akt activation. Pretreatment of cells with ERK inhibitor (U0126) and PI3K inhibitor (LY294002) significantly potentiated the inhibitory effect of RuPOP on cell growth, migration and invasion. Moreover, the alternation in the expression levels of metastatic regulatory proteins, including uPA, MMP-2/-9, and inhibition of VEGF secretion were also observed after RuPOP treatment. These results demonstrate the inhibitory effect of RuPOP on the growth and metastasis of cancer cells and the enhancement of TRAIL-induced apoptosis though suppression of FAK-mediated signaling. Furthermore, RuPOP exhibits the potential to be developed as a metal-based antimetastatic agent and chemosensitizer of TRAIL for the treatment of human metastatic cancers. PMID:25778692

  7. Ameliorative effect of vanadyl(IV)-ascorbate complex on high-fat high-sucrose diet-induced hyperglycemia, insulin resistance, and oxidative stress in mice.

    PubMed

    Liu, Yanjun; Xu, Jie; Guo, Yongli; Xue, Yong; Wang, Jingfeng; Xue, Changhu

    2015-10-01

    There is mounting evidence demonstrating causative links between hyperglycemia, oxidative stress, and insulin resistance, the core pathophysiological features of type 2 diabetes mellitus. Using a combinational approach, we synthesized a vanadium-antioxidant (i.e., l-ascorbic acid) complex and examined its effect on insulin resistance and oxidative stress. This study was designed to examine whether vanadyl(IV)-ascorbate complex (VOAsc) would reduce oxidative stress, hyperglycemia, and insulin resistance in high-fat high-sucrose diet (HFSD)-induced type 2 diabetes in mice. Male C57BL/6J mice were fed a HFSD for 12 weeks to induce insulin resistance, rendering them diabetic. Diabetic mice were treated with rosiglitazone, sodium l-ascorbate, or VOAsc. At the end of treatment, fasting blood glucose, fasting serum insulin, homeostasis model assessment-insulin resistance index, and serum adipocytokine levels were measured. Serum levels of nitric oxide (NO) parameters were also determined. The liver was isolated and used for determination of malondialdehyde, reduced glutathione, and catalase levels, and superoxide dismutase and glutathione peroxidase activities. VOAsc groups exhibited significant reductions in serum adipocytokine and NO levels, and oxidative stress parameters compared to the corresponding values in the untreated diabetic mice. The results indicated that VOAsc is non-toxic. In conclusion, we identified VOAsc as a potentially effective adjunct therapy for the management of type 2 diabetes. PMID:26302923

  8. Analysis of protein-RNA interactions in CRISPR proteins and effector complexes by UV-induced cross-linking and mass spectrometry.

    PubMed

    Sharma, Kundan; Hrle, Ajla; Kramer, Katharina; Sachsenberg, Timo; Staals, Raymond H J; Randau, Lennart; Marchfelder, Anita; van der Oost, John; Kohlbacher, Oliver; Conti, Elena; Urlaub, Henning

    2015-11-01

    Ribonucleoprotein (RNP) complexes play important roles in the cell by mediating basic cellular processes, including gene expression and its regulation. Understanding the molecular details of these processes requires the identification and characterization of protein-RNA interactions. Over the years various approaches have been used to investigate these interactions, including computational analyses to look for RNA binding domains, gel-shift mobility assays on recombinant and mutant proteins as well as co-crystallization and NMR studies for structure elucidation. Here we report a more specialized and direct approach using UV-induced cross-linking coupled with mass spectrometry. This approach permits the identification of cross-linked peptides and RNA moieties and can also pin-point exact RNA contact sites within the protein. The power of this method is illustrated by the application to different single- and multi-subunit RNP complexes belonging to the prokaryotic adaptive immune system, CRISPR-Cas (CRISPR: clustered regularly interspaced short palindromic repeats; Cas: CRISPR associated). In particular, we identified the RNA-binding sites within three Cas7 protein homologs and mapped the cross-linking results to reveal structurally conserved Cas7 - RNA binding interfaces. These results demonstrate the strong potential of UV-induced cross-linking coupled with mass spectrometry analysis to identify RNA interaction sites on the RNA binding proteins. PMID:26071038

  9. Ruthenium Polypyridyl Complex Inhibits Growth and Metastasis of Breast Cancer Cells by Suppressing FAK signaling with Enhancement of TRAIL-induced Apoptosis

    NASA Astrophysics Data System (ADS)

    Cao, Wenqiang; Zheng, Wenjie; Chen, Tianfeng

    2015-03-01

    Ruthenium-based complexes have emerged as promising antitumor and antimetastatic agents during the past decades. However, the limited understanding of the antimetastatic mechanisms of these agents is a roadblock to their clinical application. Herein, we reported that, RuPOP, a ruthenium polypyridyl complex with potent antitumor activity, was able to effectively inhibit growth and metastasis of MDA-MB-231 cells and synergistically enhance TRAIL-induced apoptosis. The selective intracellular uptake and cytotoxic effect of RuPOP was found associated with transferring receptor (TfR)-mediated endocytosis. Further investigation on intracellular mechanisms reveled that RuPOP notably suppressed FAK-mediated ERK and Akt activation. Pretreatment of cells with ERK inhibitor (U0126) and PI3K inhibitor (LY294002) significantly potentiated the inhibitory effect of RuPOP on cell growth, migration and invasion. Moreover, the alternation in the expression levels of metastatic regulatory proteins, including uPA, MMP-2/-9, and inhibition of VEGF secretion were also observed after RuPOP treatment. These results demonstrate the inhibitory effect of RuPOP on the growth and metastasis of cancer cells and the enhancement of TRAIL-induced apoptosis though suppression of FAK-mediated signaling. Furthermore, RuPOP exhibits the potential to be developed as a metal-based antimetastatic agent and chemosensitizer of TRAIL for the treatment of human metastatic cancers.

  10. Structure of Aquifex aeolicus argonaute highlights conformational flexibility of the PAZ domain as a potential regulator of RNA-induced silencing complex function.

    PubMed

    Rashid, Umar Jan; Paterok, Dirk; Koglin, Alexander; Gohlke, Holger; Piehler, Jacob; Chen, Julian C-H

    2007-05-01

    Gene silencing mediated by RNA interference requires the sequence-specific recognition of target mRNA by the endonuclease Argonaute, the primary enzymatic component of the RNA-induced silencing complex. We report the crystal structure of Aquifex aeolicus Argonaute, refined at 3.2A resolution. Relative to recent Argonaute structures, a 24 degrees reorientation of the PAZ domain in our structure opens a basic cleft between the N-terminal and PAZ domains, exposing the guide strand binding pocket of PAZ. This rearrangement leads to a branched, Y-shaped system of grooves that extends through the molecule and merges in a central channel containing the catalytic residues. A 5.5-ns molecular dynamics simulation of Argonaute shows a strong tendency of the PAZ and N-terminal domains to be mobile. Binding of single-stranded DNA to Argonaute monitored by total internal reflection fluorescence spectroscopy shows biphasic kinetics, also indicative of domain rearrangement upon DNA binding. Conformational rearrangement of the PAZ domain may therefore be critical for the catalytic cycle of Argonaute and the RNA-induced silencing complex. PMID:17130125

  11. Oxidative stress and hypermethylation induced by exposure of Oreochromis niloticus to complex environmental mixtures of river water from Cubatão do Sul, Brazil.

    PubMed

    Fuzinatto, Cristiane Funghetto; Flohr, Letícia; Melegari, Sílvia Pedroso; Matias, William Gerson

    2015-04-01

    In this study, we investigated the effects of oxidative stress and hypermethylation through lipid peroxidation and DNA methylation, respectively, in erythrocytes of Oreochromis niloticus exposed to environmental complex mixture of water from Cubatão do Sul River throughout the year. This river is the source of drinking water for the region of Florianópolis, the capital of Santa Catarina State, Brazil. Lipid peroxidation was quantified by the rate of malondialdehyde (MDA) formation, and DNA methylation was quantified by the rate of 5-methyldeoxycytosine (m(5)dC) formation. In all studied sites, the river water samples caused metabolic changes