WorldWideScience

Sample records for chimera

  1. Smallest chimera states

    Science.gov (United States)

    Maistrenko, Yuri; Brezetsky, Serhiy; Jaros, Patrycja; Levchenko, Roman; Kapitaniak, Tomasz

    2017-01-01

    We demonstrate that chimera behavior can be observed in small networks consisting of three identical oscillators, with mutual all-to-all coupling. Three different types of chimeras, characterized by the coexistence of two coherent oscillators and one incoherent oscillator (i.e., rotating with another frequency) have been identified, where the oscillators show periodic (two types) and chaotic (one type) behaviors. Typical bifurcations at the transitions from full synchronization to chimera states and between different types of chimeras have been described. Parameter regions for the chimera states are obtained in the form of Arnold tongues, issued from a singular parameter point. Our analysis suggests that chimera states can be observed in small networks relevant to various real-world systems.

  2. Chimeras and human dignity.

    Science.gov (United States)

    de Melo-Martín, Inmaculada

    2008-12-01

    Discussions about whether new biomedical technologies threaten or violate human dignity are now common. Indeed, appeals to human dignity have played a central role in national and international debates about whether to allow particular kinds of biomedical investigations. The focus of this paper is on chimera research. I argue here that both those who claim that particular types of human-nonhuman chimera research threaten human dignity and those who argue that such threat does not exist fail to make their case. I first introduce some of the arguments that have been offered supporting the claim that the creation of certain sorts of chimeras threatens or violates human dignity. I next present opponents' assessments of such arguments. Finally I critically analyze both the critics' and the supporters' claims about whether chimera research threatens human dignity.

  3. Chimera and other fertilization errors.

    Science.gov (United States)

    Malan, V; Vekemans, M; Turleau, C

    2006-11-01

    The finding of a mixture of 46,XX and 46,XY cells in an individual has been rarely reported in literature. It usually results in individuals with ambiguous genitalia. Approximately 10% of true human hermaphrodites show this type of karyotype. However, the underlying mechanisms are poorly understood. It may be the result of mosaicism or chimerism. By definition, a chimera is produced by the fusion of two different zygotes in a single embryo, while a mosaic contains genetically different cells issued from a single zygote. Several mechanisms are involved in the production of chimera. Stricto sensu, chimerism occurs from the post-zygotic fusion of two distinct embryos leading to a tetragametic chimera. In addition, there are other entities, which are also referred to as chimera: parthenogenetic chimera and chimera resulting from fertilization of the second polar body. Furthermore, a particular type of chimera called 'androgenetic chimera' recently described in fetuses with placental mesenchymal dysplasia and in rare patients with Beckwith-Wiedemann syndrome is discussed. Strategies to study mechanisms leading to the production of chimera and mosaics are also proposed.

  4. Emergence of multicluster chimera states.

    Science.gov (United States)

    Yao, Nan; Huang, Zi-Gang; Grebogi, Celso; Lai, Ying-Cheng

    2015-09-09

    A remarkable phenomenon in spatiotemporal dynamical systems is chimera state, where the structurally and dynamically identical oscillators in a coupled networked system spontaneously break into two groups, one exhibiting coherent motion and another incoherent. This phenomenon was typically studied in the setting of non-local coupling configurations. We ask what can happen to chimera states under systematic changes to the network structure when links are removed from the network in an orderly fashion but the local coupling topology remains invariant with respect to an index shift. We find the emergence of multicluster chimera states. Remarkably, as a parameter characterizing the amount of link removal is increased, chimera states of distinct numbers of clusters emerge and persist in different parameter regions. We develop a phenomenological theory, based on enhanced or reduced interactions among oscillators in different spatial groups, to explain why chimera states of certain numbers of clusters occur in certain parameter regions. The theoretical prediction agrees well with numerics.

  5. A classification scheme for chimera states

    Science.gov (United States)

    Kemeth, Felix P.; Haugland, Sindre W.; Schmidt, Lennart; Kevrekidis, Ioannis G.; Krischer, Katharina

    2016-09-01

    We present a universal characterization scheme for chimera states applicable to both numerical and experimental data sets. The scheme is based on two correlation measures that enable a meaningful definition of chimera states as well as their classification into three categories: stationary, turbulent, and breathing. In addition, these categories can be further subdivided according to the time-stationarity of these two measures. We demonstrate that this approach is both consistent with previously recognized chimera states and enables us to classify states as chimeras which have not been categorized as such before. Furthermore, the scheme allows for a qualitative and quantitative comparison of experimental chimeras with chimeras obtained through numerical simulations.

  6. Recurrence quantification analysis of chimera states

    Science.gov (United States)

    Santos, M. S.; Szezech, J. D.; Batista, A. M.; Caldas, I. L.; Viana, R. L.; Lopes, S. R.

    2015-10-01

    Chimera states, characterised by coexistence of coherence and incoherence in coupled dynamical systems, have been found in various physical systems, such as mechanical oscillator networks and Josephson-junction arrays. We used recurrence plots to provide graphical representations of recurrent patterns and identify chimera states. Moreover, we show that recurrence plots can be used as a diagnostic of chimera states and also to identify the chimera collapse.

  7. Chimera and chimera-like states in populations of nonlocally coupled homogeneous and heterogeneous chemical oscillators

    Science.gov (United States)

    Nkomo, Simbarashe; Tinsley, Mark R.; Showalter, Kenneth

    2016-09-01

    Chimera and chimera-like states are characterized in populations of photochemically coupled Belousov-Zhabotinsky (BZ) oscillators. Simple chimeras and chimera states with multiple and traveling phase clusters, phase-slip behavior, and chimera-like states with phase waves are described. Simulations with a realistic model of the discrete BZ system of populations of homogeneous and heterogeneous oscillators are compared with each other and with experimental behavior.

  8. Constraining QGP properties with CHIMERA

    Science.gov (United States)

    Garishvili, Irakli; Abelev, Betty; Cheng, Michael; Glenn, Andrew; Soltz, Ron

    2011-10-01

    Understanding essential properties of strongly interacting matter is arguably the most important goal of the relativistic heavy-ion programs both at RHIC and the LHC. In particular, constraining observables such as ratio of shear viscosity to entropy density, η/s, initial temperature, Tinit, and energy density is of critical importance. For this purpose we have developed CHIMERA, Comprehensive Heavy Ion Model Reporting and Evaluation Algorithm. CHIMERA is designed to facilitate global statistical comparison of results from our multi-stage hydrodynamics/hadron cascade model of heavy ion collisions to the key soft observables (HBT, elliptic flow, spectra) measured at RHIC and the LHC. Within this framework the data representing multiple different measurements from different experiments are compiled into single format. One of the unique features of CHIMERA is, that in addition to taking into account statistical errors, it also treats different types of systematic uncertainties. The hydrodynamics/hadron cascade model used in the framework incorporates different initial state conditions, pre-equilibrium flow, the UVH2+1 viscous hydro model, Cooper-Frye freezeout, and the UrQMD hadronic cascade model. The sensitivity of the observables to the equation of state (EoS) is explored using several EoS's in the hydrodynamic evolution. The latest results from CHIMERA, including data from the LHC, will be presented.

  9. Ethical considerations in chimera research.

    Science.gov (United States)

    Hermerén, Göran

    2015-01-01

    The development of human pluripotent stem cells has opened up the possibility to analyse the function of human cells and tissues in animal hosts, thus generating chimeras. Although such lines of research have great potential for both basic and translational science, they also raise unique ethical issues that must be considered.

  10. Pinning control of chimera states

    Science.gov (United States)

    Gambuzza, Lucia Valentina; Frasca, Mattia

    2016-08-01

    The position of the coherent and incoherent domain of a chimera state in a ring of nonlocally coupled oscillators is strongly influenced by the initial conditions, making nontrivial the problem of confining them in a specific region of the structure. In this paper we propose the use of spatial pinning to induce a chimera state where the nodes belonging to one domain, either the coherent or the incoherent, are fixed by the control action. We design two different techniques according to the dynamics to be forced in the region of pinned nodes, and validate them on FitzHugh-Nagumo and Kuramoto oscillators. Furthermore, we introduce a suitable strategy to deal with the effects of finite size in small structures.

  11. The smallest chimera state for coupled pendula

    Science.gov (United States)

    Wojewoda, Jerzy; Czolczynski, Krzysztof; Maistrenko, Yuri; Kapitaniak, Tomasz

    2016-01-01

    Chimera states in the systems of coupled identical oscillators are spatiotemporal patterns in which different groups of oscillators can exhibit coexisting synchronous and incoherent behaviors despite homogeneous coupling. Although these states are typically observed in large ensembles of oscillators, recently it has been suggested that chimera states may occur in the systems with small numbers of oscillators. Here, considering three coupled pendula showing chaotic behavior, we find the pattern of the smallest chimera state, which is characterized by the coexistence of two synchronized and one incoherent oscillator. We show that this chimera state can be observed in simple experiments with mechanical oscillators, which are controlled by elementary dynamical equations derived from Newton’s laws. Our finding suggests that chimera states are observable in small networks relevant to various real-world systems. PMID:27713483

  12. The smallest chimera state for coupled pendula

    Science.gov (United States)

    Wojewoda, Jerzy; Czolczynski, Krzysztof; Maistrenko, Yuri; Kapitaniak, Tomasz

    2016-10-01

    Chimera states in the systems of coupled identical oscillators are spatiotemporal patterns in which different groups of oscillators can exhibit coexisting synchronous and incoherent behaviors despite homogeneous coupling. Although these states are typically observed in large ensembles of oscillators, recently it has been suggested that chimera states may occur in the systems with small numbers of oscillators. Here, considering three coupled pendula showing chaotic behavior, we find the pattern of the smallest chimera state, which is characterized by the coexistence of two synchronized and one incoherent oscillator. We show that this chimera state can be observed in simple experiments with mechanical oscillators, which are controlled by elementary dynamical equations derived from Newton’s laws. Our finding suggests that chimera states are observable in small networks relevant to various real-world systems.

  13. Generation of axolotl hematopoietic chimeras

    Directory of Open Access Journals (Sweden)

    David Lopez

    2015-02-01

    Full Text Available Wound repair is an extremely complex process that requires precise coordination between various cell types including immune cells.  Unfortunately, in mammals this usually results in scar formation instead of restoration of the original fully functional tissue, otherwise known as regeneration.  Various animal models like frogs and salamanders are currently being studied to determine the intracellular and intercellular pathways, controlled by gene expression, that elicit cell proliferation, differentiation, and migration of cells during regenerative healing.  Now, the necessary genetic tools to map regenerative pathways are becoming available for the axolotl salamander, thus allowing comparative studies between scarring and regeneration.  Here, we describe in detail three methods to produce axolotl hematopoietic cell-tagged chimeras for the study of hematopoiesis and regeneration.

  14. Chimera States in Mechanical Oscillator Networks

    CERN Document Server

    Martens, Erik Andreas; Fourrière, Antoine; Hallatschek, Oskar

    2013-01-01

    The synchronization of coupled oscillators is a fascinating manifestation of self-organization that nature employs to orchestrate essential processes of life, such as the beating of the heart. While it was long thought that synchrony or disorder were mutually exclusive steady states for a network of identical oscillators, numerous theoretical studies in recent years revealed the intriguing possibility of 'chimera states', in which the symmetry of the oscillator population is broken into a synchronous and an asynchronous part. However, a striking lack of empirical evidence raises the question of whether chimeras are indeed characteristic to natural systems. This calls for a palpable realization of chimera states without any fine-tuning, from which physical mechanisms underlying their emergence can be uncovered. Here, we devise a simple experiment with mechanical oscillators coupled in a hierarchical network to show that chimeras emerge naturally from a competition between two antagonistic synchronization patte...

  15. Transferring morality to human-nonhuman chimeras.

    Science.gov (United States)

    Piotrowska, Monika

    2014-01-01

    Human-nonhuman chimeras have been the focus of ethical controversies for more than a decade, yet some related issues remain unaddressed. For example, little has been said about the relationship between the origin of transferred cells and the morally relevant capacities to which they may give rise. Consider, for example, a developing mouse fetus that receives a brain stem cell transplant from a human and another that receives a brain stem cell transplant from a dolphin. If both chimeras acquire morally relevant capacities as a result of transplantation, and if those capacities are indistinguishable, should the difference in cell origin matter to how we classify these creatures? I argue that if morally relevant capacities are easy to detect, cell origin is irrelevant to how the chimera ought to be treated. However, if such capacities are hard to detect, cell origin should play a role in considerations about how to treat the chimera.

  16. Imperfect traveling chimera states induced by local synaptic gradient coupling

    Science.gov (United States)

    Bera, Bidesh K.; Ghosh, Dibakar; Banerjee, Tanmoy

    2016-07-01

    In this paper, we report the occurrence of chimera patterns in a network of neuronal oscillators, which are coupled through local, synaptic gradient coupling. We discover a new chimera pattern, namely the imperfect traveling chimera state, where the incoherent traveling domain spreads into the coherent domain of the network. Remarkably, we also find that chimera states arise even for one-way local coupling, which is in contrast to the earlier belief that only nonlocal, global, or nearest-neighbor local coupling can give rise to chimera state; this find further relaxes the essential connectivity requirement of getting a chimera state. We choose a network of identical bursting Hindmarsh-Rose neuronal oscillators, and we show that depending upon the relative strength of the synaptic and gradient coupling, several chimera patterns emerge. We map all the spatiotemporal behaviors in parameter space and identify the transitions among several chimera patterns, an in-phase synchronized state, and a global amplitude death state.

  17. Chimera states in mechanical oscillator networks

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Thutupalli, Shashi; Fourrière, Antoine

    2013-01-01

    The synchronization of coupled oscillators is a fascinating manifestation of self-organization that nature uses to orchestrate essential processes of life, such as the beating of the heart. Although it was long thought that synchrony and disorder were mutually exclusive steady states for a network...... of identical oscillators, numerous theoretical studies in recent years have revealed the intriguing possibility of "chimera states," in which the symmetry of the oscillator population is broken into a synchronous part and an asynchronous part. However, a striking lack of empirical evidence raises the question...... of whether chimeras are indeed characteristic of natural systems. This calls for a palpable realization of chimera states without any fine-tuning, from which physical mechanisms underlying their emergence can be uncovered. Here, we devise a simple experiment with mechanical oscillators coupled...

  18. Turbulent chimeras in large semiconductor laser arrays

    CERN Document Server

    Shena, Joniald; Kovanis, Vassilios; Tsironis, George P

    2016-01-01

    Semiconductor laser arrays have been investigated experimentally and theoretically from the viewpoint of temporal and spatial coherence for the past forty years. In this work, we are focusing on a rather novel complex collective behavior, namely chimera states, where synchronized clusters of emitters coexist with unsynchronized ones. For the first time, we find such states exist in large diode arrays based on quantum well gain media with nearest-neighbor interactions. The crucial parameters are the evanescent coupling strength and the relative optical frequency detuning between the emitters of the array. By employing a recently proposed figure of merit for classifying chimera states, we provide quantitative and qualitative evidence for the observed dynamics. The corresponding chimeras are identified as turbulent according to the irregular temporal behavior of the classification measure. Such studies may be the springboard for designing next generation photonic emitters providing on demand diverse waveforms.

  19. A Discontinuous Galerkin Chimera Overset Solver

    Science.gov (United States)

    Galbraith, Marshall Christopher

    This work summarizes the development of an accurate, efficient, and flexible Computational Fluid Dynamics computer code that is an improvement relative to the state of the art. The improved accuracy and efficiency is obtained by using a high-order discontinuous Galerkin (DG) discretization scheme. In order to maximize the computational efficiency, quadrature-free integration and numerical integration optimized as matrix-vector multiplications is employed and implemented through a pre-processor (PyDG). Using the PyDG pre-processor, a C++ polynomial library has been developed that uses overloaded operators to design an efficient Domain Specific Language (DSL) that allows expressions involving polynomials to be written as if they are scalars. The DSL, which makes the syntax of computer code legible and intuitive, promotes maintainability of the software and simplifies the development of additional capabilities. The flexibility of the code is achieved by combining the DG scheme with the Chimera overset method. The Chimera overset method produces solutions on a set of overlapping grids that communicate through an exchange of data on grid boundaries (known as artificial boundaries). Finite volume and finite difference discretizations use fringe points, which are layers of points on the artificial boundaries, to maintain the interior stencil on artificial boundaries. The fringe points receive solution values interpolated from overset grids. Proper interpolation requires fringe points to be contained in overset grids. Insufficient overlap must be corrected by modifying the grid system. The Chimera scheme can also exclude regions of grids that lie outside the computational domain; a process commonly known as hole cutting. The Chimera overset method has traditionally enabled the use of high-order finite difference and finite volume approaches such as WENO and compact differencing schemes, which require structured meshes, for modeling fluid flow associated with complex

  20. Basins of Attraction for Chimera States

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Panaggio, Mark; Abrams, Daniel

    2016-01-01

    Chimera states---curious symmetry-broken states in systems of identical coupled oscillators---typically occur only for certain initial conditions. Here we analyze their basins of attraction in a simple system comprised of two populations. Using perturbative analysis and numerical simulation we...

  1. α-Peptide/ß-Peptoid Chimeras

    DEFF Research Database (Denmark)

    Olsen, Christian Adam; Bonke, Gitte; Vedel, Line;

    2007-01-01

    We describe the synthesis and characterization of the first generation of oligomers consisting of alternating repeats of a-amino acids and chiral N-alkyl-ß-alanine (ß-peptoid) residues. These chimeras are stable toward proteolysis, non-hemolytic, and possess antibacterial activity comparable...... peptidomimetic backbone construct for biologically active ligands....

  2. Intermittent chaotic chimeras for coupled rotators.

    Science.gov (United States)

    Olmi, Simona; Martens, Erik A; Thutupalli, Shashi; Torcini, Alessandro

    2015-09-01

    Two symmetrically coupled populations of N oscillators with inertia m display chaotic solutions with broken symmetry similar to experimental observations with mechanical pendulums. In particular, we report evidence of intermittent chaotic chimeras, where one population is synchronized and the other jumps erratically between laminar and turbulent phases. These states have finite lifetimes diverging as a power law with N and m. Lyapunov analyses reveal chaotic properties in quantitative agreement with theoretical predictions for globally coupled dissipative systems.

  3. Coherence-Resonance Chimeras in a Network of Excitable Elements.

    Science.gov (United States)

    Semenova, Nadezhda; Zakharova, Anna; Anishchenko, Vadim; Schöll, Eckehard

    2016-07-01

    We demonstrate that chimera behavior can be observed in nonlocally coupled networks of excitable systems in the presence of noise. This phenomenon is distinct from classical chimeras, which occur in deterministic oscillatory systems, and it combines temporal features of coherence resonance, i.e., the constructive role of noise, and spatial properties of chimera states, i.e., the coexistence of spatially coherent and incoherent domains in a network of identical elements. Coherence-resonance chimeras are associated with alternating switching of the location of coherent and incoherent domains, which might be relevant in neuronal networks.

  4. Assessing reprogramming by chimera formation and tetraploid complementation.

    Science.gov (United States)

    Li, Xin; Xia, Bao-long; Li, Wei; Zhou, Qi

    2015-01-01

    Pluripotent stem cells can be evaluated by pluripotent markers expression, embryoid body aggregation, teratoma formation, chimera contribution and even more, tetraploid complementation. Whether iPS cells in general are functionally equivalent to normal ESCs is difficult to establish. Here, we present the detailed procedure for chimera formation and tetraploid complementation, the most stringent criterion, to assessing pluripotency.

  5. Chimera patterns in the Kuramoto-Battogtokh model

    Science.gov (United States)

    Smirnov, Lev; Osipov, Grigory; Pikovsky, Arkady

    2017-02-01

    Kuramoto and Battogtokh (2002 Nonlinear Phenom. Complex Syst. 5 380) discovered chimera states represented by stable coexisting synchrony and asynchrony domains in a lattice of coupled oscillators. After a reformulation in terms of a local order parameter, the problem can be reduced to partial differential equations. We find uniformly rotating, spatially periodic chimera patterns as solutions of a reversible ordinary differential equation, and demonstrate a plethora of such states. In the limit of neutral coupling they reduce to analytical solutions in the form of one- and two-point chimera patterns as well as localized chimera solitons. Patterns at weakly attracting coupling are characterized by virtue of a perturbative approach. Stability analysis reveals that only the simplest chimeras with one synchronous region are stable.

  6. Metaphysical and ethical perspectives on creating animal-human chimeras.

    Science.gov (United States)

    Eberl, Jason T; Ballard, Rebecca A

    2009-10-01

    This paper addresses several questions related to the nature, production, and use of animal-human (a-h) chimeras. At the heart of the issue is whether certain types of a-h chimeras should be brought into existence, and, if they are, how we should treat such creatures. In our current research environment, we recognize a dichotomy between research involving nonhuman animal subjects and research involving human subjects, and the classification of a research protocol into one of these categories will trigger different ethical standards as to the moral permissibility of the research in question. Are a-h chimeras entitled to the more restrictive and protective ethical standards applied to human research subjects? We elucidate an Aristotelian-Thomistic metaphysical framework in which to argue how such chimeras ought to be defined ontologically. We then examine when the creation of, and experimentation upon, certain types of a-h chimeras may be morally permissible.

  7. Multi-headed chimera states in coupled pendula

    Science.gov (United States)

    Jaros, P.; Borkowski, L.; Witkowski, B.; Czolczynski, K.; Kapitaniak, T.

    2015-07-01

    We discuss the occurrence of the chimera states in the network of coupled, excited by the clock's mechanisms pendula. We find the patterns of multi-headed chimera states in which pendula clustered in different heads behave differently (oscillate with different frequencies) and create different types of synchronous states (complete or phase synchronization). The mathematical model of the network shows that the observed chimera states are controlled by elementary dynamical equations derived from the Newton's laws that are ubiquitous in many physical and engineering systems.

  8. Fast clique minor generation in Chimera qubit connectivity graphs

    Science.gov (United States)

    Boothby, Tomas; King, Andrew D.; Roy, Aidan

    2016-01-01

    The current generation of D-Wave quantum annealing processor is designed to minimize the energy of an Ising spin configuration whose pairwise interactions lie on the edges of a Chimera graph C_{M,N,L}. In order to solve an Ising spin problem with arbitrary pairwise interaction structure, the corresponding graph must be minor-embedded into a Chimera graph. We define a combinatorial class of native clique minors in Chimera graphs with vertex images of uniform, near minimal size and provide a polynomial-time algorithm that finds a maximum native clique minor in a given induced subgraph of a Chimera graph. These minors allow improvement over recent work and have immediate practical applications in the field of quantum annealing.

  9. Chimera in a neuronal network model of the cat brain

    OpenAIRE

    Santos, M. S.; Szezech Jr., J. D.; Borges, F. S.; Iarosz, K. C.; Caldas, I. L.; Batista, A. M.; Viana, R. L.; Kurths, J.

    2016-01-01

    Neuronal systems have been modeled by complex networks in different description levels. Recently, it has been verified that networks can simultaneously exhibit one coherent and other incoherent domain, known as chimera states. In this work, we study the existence of chimera states in a network considering the connectivity matrix based on the cat cerebral cortex. The cerebral cortex of the cat can be separated in 65 cortical areas organised into the four cognitive regions: visual, auditory, so...

  10. Tools for integrated sequence-structure analysis with UCSF Chimera

    Directory of Open Access Journals (Sweden)

    Huang Conrad C

    2006-07-01

    Full Text Available Abstract Background Comparing related structures and viewing the structures in the context of sequence alignments are important tasks in protein structure-function research. While many programs exist for individual aspects of such work, there is a need for interactive visualization tools that: (a provide a deep integration of sequence and structure, far beyond mapping where a sequence region falls in the structure and vice versa; (b facilitate changing data of one type based on the other (for example, using only sequence-conserved residues to match structures, or adjusting a sequence alignment based on spatial fit; (c can be used with a researcher's own data, including arbitrary sequence alignments and annotations, closely or distantly related sets of proteins, etc.; and (d interoperate with each other and with a full complement of molecular graphics features. We describe enhancements to UCSF Chimera to achieve these goals. Results The molecular graphics program UCSF Chimera includes a suite of tools for interactive analyses of sequences and structures. Structures automatically associate with sequences in imported alignments, allowing many kinds of crosstalk. A novel method is provided to superimpose structures in the absence of a pre-existing sequence alignment. The method uses both sequence and secondary structure, and can match even structures with very low sequence identity. Another tool constructs structure-based sequence alignments from superpositions of two or more proteins. Chimera is designed to be extensible, and mechanisms for incorporating user-specific data without Chimera code development are also provided. Conclusion The tools described here apply to many problems involving comparison and analysis of protein structures and their sequences. Chimera includes complete documentation and is intended for use by a wide range of scientists, not just those in the computational disciplines. UCSF Chimera is free for non-commercial use and is

  11. Modeling Quark Gluon Plasma Using CHIMERA

    Science.gov (United States)

    Abelev, Betty

    2011-09-01

    We attempt to model Quark Gluon Plasma (QGP) evolution from the initial Heavy Ion collision to the final hadronic gas state by combining the Glauber model initial state conditions with eccentricity fluctuations, pre-equilibrium flow, UVH2+1 viscous hydrodynamics with lattice QCD Equation of State (EoS), a modified Cooper-Frye freeze-out and the UrQMD hadronic cascade. We then evaluate the model parameters using a comprehensive analytical framework which together with the described model we call CHIMERA. Within our framework, the initial state parameters, such as the initial temperature (Tinit), presence or absence of initial flow, viscosity over entropy density (η/S) and different Equations of State (EoS), are varied and then compared simultaneously to several experimental data observables: HBT radii, particle spectra and particle flow. χ2/nds values from comparison to the experimental data for each set of initial parameters will then used to find the optimal description of the QGP with parameters that are difficult to obtain experimentally, but are crucial to understanding of the matter produced.

  12. Modeling Quark Gluon Plasma Using CHIMERA

    CERN Document Server

    Abelev, Betty B I

    2011-01-01

    We attempt to model Quark Gluon Plasma (QGP) evolution from the initial Heavy Ion collision to the final hadronic gas state by combining the Glauber model initial state conditions with eccentricity fluctuations, pre-equilibrium flow, UVH2+1 viscous hydrodynamics with lattice QCD Equation of State (EoS), a modified Cooper-Frye freeze-out and the UrQMD hadronic cascade. We then evaluate the model parameters using a comprehensive analytical framework which together with the described model we call CHIMERA. Within our framework, the initial state parameters, such as the initial temperature (T$_{\\mathrm{init}}$), presence or absence of initial flow, viscosity over entropy density ($\\eta$/s) and different Equations of State (EoS), are varied and then compared simultaneously to several experimental data observables: HBT radii, particle spectra and particle flow. $\\chi^2$/nds values from comparison to the experimental data for each set of initial parameters will then used to find the optimal description of the QGP wi...

  13. Chimera states in coupled Kuramoto oscillators with inertia

    Energy Technology Data Exchange (ETDEWEB)

    Olmi, Simona, E-mail: simona.olmi@fi.isc.cnr.it [CNR - Consiglio Nazionale delle Ricerche - Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); INFN Sez. Firenze, via Sansone, 1 - I-50019 Sesto Fiorentino (Italy)

    2015-12-15

    The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry.

  14. Chimera States in Two Populations with Heterogeneous Phase-lag

    DEFF Research Database (Denmark)

    Martens, Erik Andreas

    2016-01-01

    The simplest network of coupled phase-oscillators exhibiting chimera states is given by two populations with disparate intra- and inter-population coupling strengths. We explore the effects of heterogeneous coupling phase-lags between the two populations. Such heterogeneity arises naturally......, we identify the bifurcations through which chimera and desynchronized states emerge. Stable chimera states and desynchronized solutions, which do not arise for homogeneous phase-lag parameters, emerge as a result of competition between synchronized in-phase, anti-phase equilibria, and fully...... incoherent states when the phase-lags are near ±π/2 (cosine coupling). These findings elucidate previous experimental results involving a network of mechanical oscillators and provide further insight into the breakdown of synchrony in biological systems....

  15. Chimera-like states in modular neural networks

    CERN Document Server

    Hizanidis, Johanne; Zamora-López, Gorka; Díaz-Guilera, Albert; Antonopoulos, Chris G

    2016-01-01

    Chimera states, namely the coexistence of coherent and incoherent behavior, were previously analyzed in complex networks. However, they have not been extensively studied in modular networks. Here, we consider the neural network of the \\textit{C.elegans} soil worm, organized into six interconnected communities, where neurons obey chaotic bursting dynamics. Neurons are assumed to be connected with electrical synapses within their communities and with chemical synapses across them. As our numerical simulations reveal, the coaction of these two types of coupling can shape the dynamics in such a way that chimera-like states can happen. They consist of a fraction of synchronized neurons which belong to the larger communities, and a fraction of desynchronized neurons which are part of smaller communities. In addition to the Kuramoto order parameter $\\rho$, we also employ other measures of coherence, such as the chimera-like $\\chi$ and metastability $\\lambda$ indices, which quantify the degree of synchronization amon...

  16. Chimeras in locally coupled SQUIDs: Lions, goats and snakes

    CERN Document Server

    Hizanidis, J; Tsironis, G P

    2016-01-01

    We report on the emergence of robust multi-clustered chimera states in a dissipative-driven system of symmetrically and locally coupled identical SQUID oscillators. The "snake-like" resonance curve of the single SQUID (Superconducting QUantum Interference Device) is the key to the formation of the chimera states and is responsible for the extreme multistability exhibited by the coupled system that leads to attractor crowding at the geometrical resonance frequency. Until now, chimera states were mostly believed to exist for nonlocal coupling. Our findings provide theoretical evidence that nearest neighbor interactions is indeed capable of supporting such states in a wide parameter range. SQUID metamaterials are the subject of intense experimental investigations and we are highly confident that the complex dynamics demonstrated in this manuscript can be confirmed in the laboratory.

  17. Chimera states and synchronization in magnetically driven SQUID metamaterials

    Science.gov (United States)

    Hizanidis, J.; Lazarides, N.; Neofotistos, G.; Tsironis, G. P.

    2016-09-01

    One-dimensional arrays of Superconducting QUantum Interference Devices (SQUIDs) form magnetic metamaterials exhibiting extraordinary properties, including tunability, dynamic multistability, negative magnetic permeability, and broadband transparency. The SQUIDs in a metamaterial interact through non-local, magnetic dipole-dipole forces, that makes it possible for multiheaded chimera states and coexisting patterns, including solitary states, to appear. The spontaneous emergence of chimera states and the role of multistability is demonstrated numerically for a SQUID metamaterial driven by an alternating magnetic field. The spatial synchronization and temporal complexity are discussed and the parameter space for the global synchronization reveals the areas of coherence-incoherence transition. Given that both one- and two-dimensional SQUID metamaterials have been already fabricated and investigated in the lab, the presence of a chimera state could in principle be detected with presently available experimental set-ups.

  18. Robust chimera states in SQUID metamaterials with local interactions

    Science.gov (United States)

    Hizanidis, J.; Lazarides, N.; Tsironis, G. P.

    2016-09-01

    We report on the emergence of robust multiclustered chimera states in a dissipative-driven system of symmetrically and locally coupled identical superconducting quantum interference device (SQUID) oscillators. The "snakelike" resonance curve of the single SQUID is the key to the formation of the chimera states and is responsible for the extreme multistability exhibited by the coupled system that leads to attractor crowding at the geometrical resonance (inductive-capacitive) frequency. Until now, chimera states were mostly believed to exist for nonlocal coupling. Our findings provide theoretical evidence that nearest-neighbor interactions are indeed capable of supporting such states in a wide parameter range. SQUID metamaterials are the subject of intense experimental investigations, and we are highly confident that the complex dynamics demonstrated in this paper can be confirmed in the laboratory.

  19. Delayed-feedback chimera states: Forced multiclusters and stochastic resonance

    Science.gov (United States)

    Semenov, V.; Zakharova, A.; Maistrenko, Y.; Schöll, E.

    2016-07-01

    A nonlinear oscillator model with negative time-delayed feedback is studied numerically under external deterministic and stochastic forcing. It is found that in the unforced system complex partial synchronization patterns like chimera states as well as salt-and-pepper-like solitary states arise on the route from regular dynamics to spatio-temporal chaos. The control of the dynamics by external periodic forcing is demonstrated by numerical simulations. It is shown that one-cluster and multi-cluster chimeras can be achieved by adjusting the external forcing frequency to appropriate resonance conditions. If a stochastic component is superimposed to the deterministic external forcing, chimera states can be induced in a way similar to stochastic resonance, they appear, therefore, in regimes where they do not exist without noise.

  20. Chimera states in uncoupled neurons induced by a multilayer structure

    CERN Document Server

    Majhi, Soumen; Ghosh, Dibakar

    2016-01-01

    Spatial coexistence of coherent and incoherent dynamics in network of coupled oscillators is called a chimera state. We study such chimera states in a network of neurons without any direct interactions but connected through another medium of neurons, forming a multilayer structure. The upper layer is thus made up of uncoupled neurons and the lower layer plays the role of a medium through which the neurons in the upper layer share information among each other. Hindmarsh-Rose neurons with square wave bursting dynamics are considered as nodes in both layers. In addition, we also discuss the existence of chimera states in presence of inter layer heterogeneity. The neurons in the bottom layer are globally connected through electrical synapses, while across the two layers chemical synapses are formed. According to our research, the competing effects of these two types of synapses can lead to chimera states in the upper layer of uncoupled neurons. Remarkably, we find a density-dependent threshold for the emergence o...

  1. Chimera states in two populations with heterogeneous phase-lag.

    Science.gov (United States)

    Martens, Erik A; Bick, Christian; Panaggio, Mark J

    2016-09-01

    The simplest network of coupled phase-oscillators exhibiting chimera states is given by two populations with disparate intra- and inter-population coupling strengths. We explore the effects of heterogeneous coupling phase-lags between the two populations. Such heterogeneity arises naturally in various settings, for example, as an approximation to transmission delays, excitatory-inhibitory interactions, or as amplitude and phase responses of oscillators with electrical or mechanical coupling. We find that breaking the phase-lag symmetry results in a variety of states with uniform and non-uniform synchronization, including in-phase and anti-phase synchrony, full incoherence (splay state), chimera states with phase separation of 0 or π between populations, and states where both populations remain desynchronized. These desynchronized states exhibit stable, oscillatory, and even chaotic dynamics. Moreover, we identify the bifurcations through which chimeras emerge. Stable chimera states and desynchronized solutions, which do not arise for homogeneous phase-lag parameters, emerge as a result of competition between synchronized in-phase, anti-phase equilibria, and fully incoherent states when the phase-lags are near ±π2 (cosine coupling). These findings elucidate previous experimental results involving a network of mechanical oscillators and provide further insight into the breakdown of synchrony in biological systems.

  2. Chimera states in two populations with heterogeneous phase-lag

    Science.gov (United States)

    Martens, Erik A.; Bick, Christian; Panaggio, Mark J.

    2016-09-01

    The simplest network of coupled phase-oscillators exhibiting chimera states is given by two populations with disparate intra- and inter-population coupling strengths. We explore the effects of heterogeneous coupling phase-lags between the two populations. Such heterogeneity arises naturally in various settings, for example, as an approximation to transmission delays, excitatory-inhibitory interactions, or as amplitude and phase responses of oscillators with electrical or mechanical coupling. We find that breaking the phase-lag symmetry results in a variety of states with uniform and non-uniform synchronization, including in-phase and anti-phase synchrony, full incoherence (splay state), chimera states with phase separation of 0 or π between populations, and states where both populations remain desynchronized. These desynchronized states exhibit stable, oscillatory, and even chaotic dynamics. Moreover, we identify the bifurcations through which chimeras emerge. Stable chimera states and desynchronized solutions, which do not arise for homogeneous phase-lag parameters, emerge as a result of competition between synchronized in-phase, anti-phase equilibria, and fully incoherent states when the phase-lags are near ± /π 2 (cosine coupling). These findings elucidate previous experimental results involving a network of mechanical oscillators and provide further insight into the breakdown of synchrony in biological systems.

  3. CHIMERA CBRN protective suit. Advanced embodiment design. Final report

    NARCIS (Netherlands)

    Bogerd, C.P.; Smit, B. de; Olarte, C.; Kane, G.; Bie, M. de; Megen, X. van; Schenk, J.; Hooop, J. de

    2015-01-01

    The Chimera project started of with the following design challenge: Designing a switchable CBRN (chemical, biological, radiological, nuclear) protective suit for soldiers, one phase being a regular work state and the other phase being a protective state to enable the soldier to get away from the tox

  4. What’s Wrong with Human/Nonhuman Chimera Research?

    Science.gov (United States)

    Hyun, Insoo

    2016-01-01

    The National Institutes of Health (NIH) is poised to lift its funding moratorium on research involving chimeric human/nonhuman embryos, pending further consideration by an NIH steering committee. The kinds of ethical concerns that seem to underlie this research and chimera research more generally can be adequately addressed. PMID:27574863

  5. Using CHIMERA detector at LNS for gamma-particle coincidences

    Directory of Open Access Journals (Sweden)

    Cardella G.

    2016-01-01

    Full Text Available We have recently evaluated the quality of γ-ray angular distributions that can be extracted in particle-gamma coincidence measurements using the CHIMERA detector at LNS. γ-rays have been detected using the CsI(Tl detectors of the spherical part of the CHIMERA array. Very clean γ-rays angular distributions were extracted in reactions induced by different stable beams impinging on 12C thin targets. The results evidenced an effect of projectile spin flip on the γ-rays angular distributions. γ-particle coincidence measurements were also performed in reactions induced by neutron rich exotic beams produced through in-flight fragmentation at LNS. In recent experiments also the Farcos array was used to improve energy and angular resolution measurements of the detected charged particles. Results obtained with both stable and radioactive beams are reported.

  6. Chimera regimes in a ring of oscillators with local nonlinear interaction

    Science.gov (United States)

    Shepelev, Igor A.; Zakharova, Anna; Vadivasova, Tatiana E.

    2017-03-01

    One of important problems concerning chimera states is the conditions of their existence and stability. Until now, it was assumed that chimeras could arise only in ensembles with nonlocal character of interactions. However, this assumption is not exactly right. In some special cases chimeras can be realized for local type of coupling [1-3]. We propose a simple model of ensemble with local coupling when chimeras are realized. This model is a ring of linear oscillators with the local nonlinear unidirectional interaction. Chimera structures in the ring are found using computer simulations for wide area of values of parameters. Diagram of the regimes on plane of control parameters is plotted and scenario of chimera destruction are studied when the parameters are changed.

  7. Chimera states in two populations with heterogeneous phase-lag

    OpenAIRE

    Martens, Erik Andreas; Bick, Christian; Panaggio, Mark J.

    2016-01-01

    The simplest network of coupled phase-oscillators exhibiting chimera states is given by two populations with disparate intra- and inter-population coupling strengths. We explore the effects of heterogeneous coupling phase-lags between the two populations. Such heterogeneity arises naturally in various settings, for example as an approximation to transmission delays, excitatory-inhibitory interactions, or as amplitude and phase responses of oscillators with electrical or mechanical coupling. W...

  8. Chimeras, moral status, and public policy: implications of the abortion debate for public policy on human/nonhuman chimera research.

    Science.gov (United States)

    Streiffer, Robert

    2010-01-01

    Researchers are increasingly interested in creating chimeras by transplanting human embryonic stem cells (hESCs) into animals early in development. One concern is that such research could confer upon an animal the moral status of a normal human adult but then impermissibly fail to accord it the protections it merits in virtue of its enhanced moral status. Understanding the public policy implications of this ethical conclusion, though, is complicated by the fact that claims about moral status cannot play an unfettered role in public policy. Arguments like those employed in the abortion debate for the conclusion that abortion should be legally permissible even if abortion is not morally permissible also support, to a more limited degree, a liberal policy on hESC research involving the creation of chimeras.

  9. Chimera states and the interplay between initial conditions and non-local coupling

    Science.gov (United States)

    Kalle, Peter; Sawicki, Jakub; Zakharova, Anna; Schöll, Eckehard

    2017-03-01

    Chimera states are complex spatio-temporal patterns that consist of coexisting domains of coherent and incoherent dynamics. We study chimera states in a network of non-locally coupled Stuart-Landau oscillators. We investigate the impact of initial conditions in combination with non-local coupling. Based on an analytical argument, we show how the coupling phase and the coupling strength are linked to the occurrence of chimera states, flipped profiles of the mean phase velocity, and the transition from a phase- to an amplitude-mediated chimera state.

  10. Characteristic distribution of finite-time Lyapunov exponents for chimera states.

    Science.gov (United States)

    Botha, André E

    2016-07-04

    Our fascination with chimera states stems partially from the somewhat paradoxical, yet fundamental trait of identical, and identically coupled, oscillators to split into spatially separated, coherently and incoherently oscillating groups. While the list of systems for which various types of chimeras have already been detected continues to grow, there is a corresponding increase in the number of mathematical analyses aimed at elucidating the fundamental reasons for this surprising behaviour. Based on the model systems, there are strong indications that chimera states may generally be ubiquitous in naturally occurring systems containing large numbers of coupled oscillators - certain biological systems and high-Tc superconducting materials, for example. In this work we suggest a new way of detecting and characterising chimera states. Specifically, it is shown that the probability densities of finite-time Lyapunov exponents, corresponding to chimera states, have a definite characteristic shape. Such distributions could be used as signatures of chimera states, particularly in systems for which the phases of all the oscillators cannot be measured directly. For such cases, we suggest that chimera states could perhaps be detected by reconstructing the characteristic distribution via standard embedding techniques, thus making it possible to detect chimera states in systems where they could otherwise exist unnoticed.

  11. Laser chimeras as a paradigm for multistable patterns in complex systems

    Science.gov (United States)

    Larger, Laurent; Penkovsky, Bogdan; Maistrenko, Yuri

    2015-07-01

    A chimera state is a rich and fascinating class of self-organized solutions developed in high-dimensional networks. Necessary features of the network for the emergence of such complex but structured motions are non-local and symmetry breaking coupling. An accurate understanding of chimera states is expected to bring important insights on deterministic mechanism occurring in many structurally similar high-dimensional dynamics such as living systems, brain operation principles and even turbulence in hydrodynamics. Here we report on a powerful and highly controllable experiment based on an optoelectronic delayed feedback applied to a wavelength tuneable semiconductor laser, with which a wide variety of chimera patterns can be accurately investigated and interpreted. We uncover a cascade of higher-order chimeras as a pattern transition from N to N+1 clusters of chaoticity. Finally, we follow visually, as the gain increases, how chimera state is gradually destroyed on the way to apparent turbulence-like system behaviour.

  12. Targeted chimera delivery to ovarian cancer cells by heterogeneous gold magnetic nanoparticle

    Science.gov (United States)

    Chen, Yao; Xu, Mengjiao; Guo, Yi; Tu, Keyao; Wu, Weimin; Wang, Jianjun; Tong, Xiaowen; Wu, Wenjuan; Qi, Lifeng; Shi, Donglu

    2017-01-01

    Efficient delivery of small interfering RNAs (siRNAs) to the targeted cells has remained a significant challenge in clinical applications. In the present study, we developed a novel aptamer-siRNA chimera delivery system mediated by cationic Au-Fe3O4 nanoparticles (NPs). The chimera constructed by VEGF RNA aptamer and Notch3 siRNA was bonded with heterogeneous Au-Fe3O4 nanoparticles by electrostatic interaction. The obtained complex exhibited much higher silencing efficiency against Notch3 gene compared with chimera alone and lipofectamine-siRNA complex, and improved the antitumor effects of the loaded chimera. Moreover, the efficient delivery of the chimera by Au-Fe3O4 NPs could reverse multi-drug resistance (MDR) of ovarian cancer cells against the chemotherapeutic drug cisplatin, indicating its potential capability for future targeted cancer therapy while overcoming MDR.

  13. Ethical aspects of creating human-nonhuman chimeras capable of human gamete production and human pregnancy.

    Science.gov (United States)

    Palacios-González, César

    2015-01-01

    In this paper I explore some of the moral issues that could emerge from the creation of human-nonhuman chimeras (HNH-chimeras) capable of human gamete production and human pregnancy. First I explore whether there is a cogent argument against the creation of HNH-chimeras that could produce human gametes. I conclude that so far there is none, and that in fact there is at least one good moral reason for producing such types of creatures. Afterwards I explore some of the moral problems that could emerge from the fact that a HNH-chimera could become pregnant with a human conceptus. I focus on two sets of problems: problems that would arise by virtue of the fact that a human is gestated by a nonhuman creature, and problems that would emerge from the fact that such pregnancies could affect the health of the HNH-chimera.

  14. Protein-DNA chimeras: synthesis of two-arm chimeras and non-mechanical effects of the DNA spring

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yong; Wang, Andrew; Qu Hao; Zocchi, Giovanni, E-mail: zocchi@physics.ucla.ed [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095-1547 (United States)

    2009-08-19

    DNA molecular springs have recently been used to control the activity of enzymes and ribozymes. In this approach, the mechanical stress exerted by the molecular spring alters the enzyme's conformation and thus the enzymatic activity. Here we describe a method alternative to our previous one to attach DNA molecular springs to proteins, where two separate DNA 'arms' are coupled to the protein and subsequently ligated. We report certain non-mechanical effects associated with the DNA spring observed in some chimeras with specific DNA sequences and the nucleotide binding enzyme guanylate kinase. If a ssDNA 'arm' is attached to the protein by one end only, we find that in some cases (depending on the DNA sequence and attachment point on the protein's surface) the unhybridized DNA arm inhibits the enzyme, while hybridization of the DNA arm leads to an apparent activation of the enzyme. One interpretation is that, in these cases, hybridization of the DNA arm removes it from the vicinity of the active site of the enzyme. We show how mechanical and non-mechanical effects of the DNA spring can be distinguished. This is important if one wants to use the protein-DNA chimeras to quantitatively study the response of the enzyme to mechanical perturbations.

  15. Chimera states in a Hodgkin-Huxley model of thermally sensitive neurons

    Science.gov (United States)

    Glaze, Tera A.; Lewis, Scott; Bahar, Sonya

    2016-08-01

    Chimera states occur when identically coupled groups of nonlinear oscillators exhibit radically different dynamics, with one group exhibiting synchronized oscillations and the other desynchronized behavior. This dynamical phenomenon has recently been studied in computational models and demonstrated experimentally in mechanical, optical, and chemical systems. The theoretical basis of these states is currently under active investigation. Chimera behavior is of particular relevance in the context of neural synchronization, given the phenomenon of unihemispheric sleep and the recent observation of asymmetric sleep in human patients with sleep apnea. The similarity of neural chimera states to neural "bump" states, which have been suggested as a model for working memory and visual orientation tuning in the cortex, adds to their interest as objects of study. Chimera states have been demonstrated in the FitzHugh-Nagumo model of excitable cells and in the Hindmarsh-Rose neural model. Here, we demonstrate chimera states and chimera-like behaviors in a Hodgkin-Huxley-type model of thermally sensitive neurons both in a system with Abrams-Strogatz (mean field) coupling and in a system with Kuramoto (distance-dependent) coupling. We map the regions of parameter space for which chimera behavior occurs in each of the two coupling schemes.

  16. Mechanisms of appearance of amplitude and phase chimera states in ensembles of nonlocally coupled chaotic systems

    Science.gov (United States)

    Bogomolov, Sergey A.; Slepnev, Andrei V.; Strelkova, Galina I.; Schöll, Eckehard; Anishchenko, Vadim S.

    2017-02-01

    We explore the bifurcation transition from coherence to incoherence in ensembles of nonlocally coupled chaotic systems. It is firstly shown that two types of chimera states, namely, amplitude and phase, can be found in a network of coupled logistic maps, while only amplitude chimera states can be observed in a ring of continuous-time chaotic systems. We reveal a bifurcation mechanism by analyzing the evolution of space-time profiles and the coupling function with varying coupling coefficient and formulate the necessary and sufficient conditions for realizing the chimera states in the ensembles.

  17. Linked and knotted chimera filaments in oscillatory systems.

    Science.gov (United States)

    Lau, Hon Wai; Davidsen, Jörn

    2016-07-01

    While the existence of stable knotted and linked vortex lines has been established in many experimental and theoretical systems, their existence in oscillatory systems and systems with nonlocal coupling has remained elusive. Here, we present strong numerical evidence that stable knots and links such as trefoils and Hopf links do exist in simple, complex, and chaotic oscillatory systems if the coupling between the oscillators is neither too short ranged nor too long ranged. In this case, effective repulsive forces between vortex lines in knotted and linked structures stabilize curvature-driven shrinkage observed for single vortex rings. In contrast to real fluids and excitable media, the vortex lines correspond to scroll wave chimeras [synchronized scroll waves with spatially extended (tubelike) unsynchronized filaments], a prime example of spontaneous synchrony breaking in systems of identical oscillators. In the case of complex oscillatory systems, this leads to a topological superstructure combining knotted filaments and synchronization defect sheets.

  18. GABAρ1/GABAAα1 receptor chimeras to study receptor desensitization

    Science.gov (United States)

    Martínez-Torres, Ataúlfo; Demuro, Angelo; Miledi, Ricardo

    2000-01-01

    γ-Aminobutyrate type C (GABAC) receptors are ligand-gated ion channels that are expressed preponderantly in the vertebrate retina and are characterized, among other things, by a very low rate of desensitization and resistance to the specific GABAA antagonist bicuculline. To examine which structural elements determine the nondesensitizing character of the human homomeric ρ1 receptor, we used a combination of gene chimeras and electrophysiology of receptors expressed in Xenopus oocytes. Two chimeric genes were constructed, made up of portions of the ρ1-subunit and of the α1-subunit of the GABAA receptor. When expressed in Xenopus oocytes, one chimeric gene (ρ1/α1) formed functional homooligomeric receptors that were fully resistant to bicuculline and were blocked by the specific GABAC antagonist (1,2,5,6-tetrahydropyridine-4-yl)methylphosphinic acid and by zinc. Moreover, these chimeric receptors had a fast-desensitizing component, even faster than that of heterooligomeric GABAA receptors, in striking contrast to the almost nil desensitization of wild-type ρ1 (wt ρ1) receptors. To see whether the fast-desensitizing characteristic of the chimera was determined by the amino acids forming the ion channels, we replaced the second transmembrane segment (TM2) of ρ1 by that of the α1-subunit of GABAA. Although the α1-subunit forms fast-desensitizing receptors when coexpressed with other GABAA subunits, the sole transfer of the α1TM2 segment to ρ1 was not sufficient to form desensitizing receptors. All this suggests that the slow-desensitizing trait of ρ1 receptors is determined by a combination of several interacting domains along the molecule. PMID:10725369

  19. Laser Chimeras as a paradigm for multi-stable patterns in complex systems

    CERN Document Server

    Larger, Laurent; Maistrenko, Yuri

    2014-01-01

    Chimera is a rich and fascinating class of self-organized solutions developed in high dimensional networks having non-local and symmetry breaking coupling features. Its accurate understanding is expected to bring important insight in many phenomena observed in complex spatio-temporal dynamics, from living systems, brain operation principles, and even turbulence in hydrodynamics. In this article we report on a powerful and highly controllable experiment based on optoelectronic delayed feedback applied to a wavelength tunable semiconductor laser, with which a wide variety of Chimera patterns can be accurately investigated and interpreted. We uncover a cascade of higher order Chimeras as a pattern transition from N to N - 1 clusters of chaoticity. Finally, we follow visually, as the gain increases, how Chimera is gradually destroyed on the way to apparent turbulence-like system behaviour.

  20. Generation of chimeras by aggregation of embryonic stem cells with diploid or tetraploid mouse embryos.

    Science.gov (United States)

    Artus, Jérôme; Hadjantonakis, Anna-Katerina

    2011-01-01

    From the hybrid creatures of the Greek and Egyptian mythologies, the concept of the chimera has evolved and, in modern day biology, refers to an organism comprises of at least two populations of genetically distinct cells. Mouse chimeras have proven an invaluable tool for the generation of genetically modified strains. In addition, chimeras have been extensively used in developmental biology as a powerful tool to analyze the phenotype of specific mutations, to attribute function to gene products and to address the question of cell autonomy versus noncell autonomy of gene function. This chapter describes a simple and economical technique used to generate mouse chimeras by embryo aggregation. Multiple aggregation combinations are described each of which can be tailored to answer particular biological questions.

  1. Chimera states in a network-organized public goods game with destructive agents

    Science.gov (United States)

    Kouvaris, Nikos E.; Requejo, Rubén J.; Hizanidis, Johanne; Díaz-Guilera, Albert

    2016-12-01

    We found that a network-organized metapopulation of cooperators, defectors, and destructive agents playing the public goods game with mutations can collectively reach global synchronization or chimera states. Global synchronization is accompanied by a collective periodic burst of cooperation, whereas chimera states reflect the tendency of the networked metapopulation to be fragmented in clusters of synchronous and incoherent bursts of cooperation. Numerical simulations have shown that the system's dynamics switches between these two steady states through a first order transition. Depending on the parameters determining the dynamical and topological properties, chimera states with different numbers of coherent and incoherent clusters are observed. Our results present the first systematic study of chimera states and their characterization in the context of evolutionary game theory. This provides a valuable insight into the details of their occurrence, extending the relevance of such states to natural and social systems.

  2. Greengenes: Chimera-checked 16S rRNA gene database and workbenchcompatible in ARB

    Energy Technology Data Exchange (ETDEWEB)

    DeSantis, T.Z.; Hugenholtz, P.; Larsen, N.; Rojas, M.; Brodie,E.L; Keller, K.; Huber, T.; Dalevi, D.; Hu, P.; Andersen, G.L.

    2006-02-01

    A 16S rRNA gene database (http://greengenes.lbl.gov) addresses limitations of public repositories by providing chimera-screening, standard alignments and taxonomic classification using multiple published taxonomies. It was revealed that incongruent taxonomic nomenclature exists among curators even at the phylum-level. Putative chimeras were identified in 3% of environmental sequences and 0.2% of records derived from isolates. Environmental sequences were classified into 100 phylum-level lineages within the Archaea and Bacteria.

  3. Chimeras in globally coupled oscillatory systems: From ensembles of oscillators to spatially continuous media

    Science.gov (United States)

    Schmidt, Lennart; Krischer, Katharina

    2015-06-01

    We study an oscillatory medium with a nonlinear global coupling that gives rise to a harmonic mean-field oscillation with constant amplitude and frequency. Two types of cluster states are found, each undergoing a symmetry-breaking transition towards a related chimera state. We demonstrate that the diffusional coupling is non-essential for these complex dynamics. Furthermore, we investigate localized turbulence and discuss whether it can be categorized as a chimera state.

  4. Effect of glycyrrhizin on pseudomonal skin infections in human-mouse chimeras.

    Directory of Open Access Journals (Sweden)

    Shohei Yoshida

    Full Text Available In our previous studies, peripheral blood lineage(-CD34(+CD31(+ cells (CD31(+ IMC appearing in severely burned patients have been characterized as inhibitor cells for the production of β-defensins (HBDs by human epidermal keratinocytes (NHEK. In this study, the effect of glycyrrhizin on pseudomonal skin infections was studied in a chimera model of thermal injury. Two different chimera models were utilized. Patient chimeras were created in murine antimicrobial peptide-depleted NOD-SCID IL-2rγ(null mice that were grafted with unburned skin tissues of severely burned patients and inoculated with the same patient peripheral blood CD31(+ IMC. Patient chimera substitutes were created in the same mice that were grafted with NHEK and inoculated with experimentally induced CD31(+ IMC. In the results, both groups of chimeras treated with glycyrrhizin resisted a 20 LD50 dose of P. aeruginosa skin infection, while all chimeras in both groups treated with saline died within 3 days of the infection. Human antimicrobial peptides were detected from the grafted site tissues of both groups of chimeras treated with glycyrrhizin, while the peptides were not detected in the same area tissues of controls. HBD-1 was produced by keratinocytes in transwell-cultures performed with CD31(+ IMC and glycyrrhizin. Also, inhibitors (IL-10 and CCL2 of HBD-1 production by keratinocytes were not detected in cultures of patient CD31(+ IMC treated with glycyrrhizin. These results indicate that sepsis stemming from pseudomonal grafted site infections in a chimera model of burn injury is controllable by glycyrrhizin. Impaired antimicrobial peptide production at the infection site of severely burned patients may be restored after treatment with glycyrrhizin.

  5. TCP: a tool for designing chimera proteins based on the tertiary structure information

    Directory of Open Access Journals (Sweden)

    Nishida Reina

    2009-01-01

    Full Text Available Abstract Background Chimera proteins are widely used for the analysis of the protein-protein interaction region. One of the major issues is the epitope analysis of the monoclonal antibody. In the analysis, a continuous portion of an antigen is sequentially substituted into a different sequence. This method works well for an antibody recognizing a linear epitope, but not for that recognizing a discontinuous epitope. Although the designing the chimera proteins based on the tertiary structure information is required in such situations, there is no appropriate tool so far. Results In light of the problem, we developed a tool named TCP (standing for a Tool for designing Chimera Proteins, which extracts some sets of mutually orthogonal cutting surfaces for designing chimera proteins using a genetic algorithm. TCP can also incorporate and consider the solvent accessible surface area information calculated by a DSSP program. The test results of our method indicate that the TCP is robust and applicable to various shapes of proteins. Conclusion We developed TCP, a tool for designing chimera proteins based on the tertiary structure information. TCP is robust and possesses several favourable features, and we believe it is a useful tool for designing chimera proteins. TCP is freely available as an additional file of this manuscript for academic and non-profit organization.

  6. Formyl peptide receptor chimeras define domains involved in ligand binding.

    Science.gov (United States)

    Perez, H D; Holmes, R; Vilander, L R; Adams, R R; Manzana, W; Jolley, D; Andrews, W H

    1993-02-05

    We have begun to study the structural requirements for the binding of formyl peptides to their specific receptors. As an initial approach, we constructed C5a-formyl peptide receptor chimeras. Unique (and identical) restriction sites were introduced within the transmembrane domains of these receptors that allowed for the exchange of specific areas. Four types of chimeric receptors were generated. 1) The C5a receptor was progressively substituted by the formyl peptide receptor. 2) The formyl peptide receptor was progressively substituted by the C5a receptor. 3) Specific domains of the C5a receptor were substituted by the corresponding domain of the formyl peptide receptor. 4) Specific domains of the formyl peptide receptor were replaced by the same corresponding domain of the C5a receptor. Wild type and chimeric receptors were transfected into COS 7 cells and their ability to bind formyl peptide determined, taking into account efficiency of transfection and expression of chimeric protein. Based on these results, a ligand binding model is presented in which the second, third, and fourth extracellular (and/or their transmembrane) domains together with the first transmembrane domain form a ligand binding pocket for formyl peptides. It is proposed that the amino-terminal domain plays a role by presumably providing a "lid" to the pocket. The carboxyl-terminal cytoplasmic tail appears to modulate ligand binding by regulating receptor affinity.

  7. Generation of an adenovirus-parvovirus chimera with enhanced oncolytic potential.

    Science.gov (United States)

    El-Andaloussi, Nazim; Bonifati, Serena; Kaufmann, Johanna K; Mailly, Laurent; Daeffler, Laurent; Deryckère, François; Nettelbeck, Dirk M; Rommelaere, Jean; Marchini, Antonio

    2012-10-01

    In this study, our goal was to generate a chimeric adenovirus-parvovirus (Ad-PV) vector that combines the high-titer and efficient gene transfer of adenovirus with the anticancer potential of rodent parvovirus. To this end, the entire oncolytic PV genome was inserted into a replication-defective E1- and E3-deleted Ad5 vector genome. As we found that parvoviral NS expression inhibited Ad-PV chimera production, we engineered the parvoviral P4 early promoter, which governs NS expression, by inserting into its sequence tetracycline operator elements. As a result of these modifications, P4-driven expression was blocked in the packaging T-REx-293 cells, which constitutively express the tetracycline repressor, allowing high-yield chimera production. The chimera effectively delivered the PV genome into cancer cells, from which fully infectious replication-competent parvovirus particles were generated. Remarkably, the Ad-PV chimera exerted stronger cytotoxic activities against various cancer cell lines, compared with the PV and Ad parental viruses, while being still innocuous to a panel of tested healthy primary human cells. This Ad-PV chimera represents a novel versatile anticancer agent which can be subjected to further genetic manipulations in order to reinforce its enhanced oncolytic capacity through arming with transgenes or retargeting into tumor cells.

  8. Engineering human cytochrome P450 enzymes into catalytically self-sufficient chimeras using molecular Lego.

    Science.gov (United States)

    Dodhia, Vikash Rajnikant; Fantuzzi, Andrea; Gilardi, Gianfranco

    2006-10-01

    The membrane-bound human cytochrome P450s have essential roles in the metabolism of endogenous compounds and drugs. Presented here are the results on the construction and characterization of three fusion proteins containing the N-terminally modified human cytochrome P450s CYP2C9, CY2C19 and CYP3A4 fused to the soluble NADPH-dependent oxidoreductase domain of CYP102A1 from Bacillus megaterium. The constructs, CYP2C9/BMR, CYP2C19/BMR and CYP3A4/BMR are well expressed in Escherichia coli as holo proteins. The chimeras can be purified in the absence of detergent and the purified enzymes are both active and correctly folded in the absence of detergent, as demonstrated by circular dichroism and functional studies. Additionally, in comparison with the parent P450 enzyme, these chimeras have greatly improved solubility properties. The chimeras are catalytically self-sufficient and present turnover rates similar to those reported for the native enzymes in reconstituted systems, unlike previously reported mammalian cytochrome P450 fusion proteins. Furthermore the specific activities of these chimeras are not dependent on the enzyme concentration present in the reaction buffer and they do not require the addition of accessory proteins, detergents or phospholipids to be fully active. The solubility, catalytic self-sufficiency and wild-type like activities of these chimeras would greatly simplify the studies of cytochrome P450 mediated drug metabolism in solution.

  9. Multicluster and traveling chimera states in nonlocal phase-coupled oscillators.

    Science.gov (United States)

    Xie, Jianbo; Knobloch, Edgar; Kao, Hsien-Ching

    2014-08-01

    Chimera states consisting of domains of coherently and incoherently oscillating identical oscillators with nonlocal coupling are studied. These states usually coexist with the fully synchronized state and have a small basin of attraction. We propose a nonlocal phase-coupled model in which chimera states develop from random initial conditions. Several classes of chimera states have been found: (a) stationary multicluster states with evenly distributed coherent clusters, (b) stationary multicluster states with unevenly distributed clusters, and (c) a single cluster state traveling with a constant speed across the system. Traveling coherent states are also identified. A self-consistent continuum description of these states is provided and their stability properties analyzed through a combination of linear stability analysis and numerical simulation.

  10. The Chimera II Real-Time Operating System for advanced sensor-based control applications

    Science.gov (United States)

    Stewart, David B.; Schmitz, Donald E.; Khosla, Pradeep K.

    1992-01-01

    Attention is given to the Chimera II Real-Time Operating System, which has been developed for advanced sensor-based control applications. The Chimera II provides a high-performance real-time kernel and a variety of IPC features. The hardware platform required to run Chimera II consists of commercially available hardware, and allows custom hardware to be easily integrated. The design allows it to be used with almost any type of VMEbus-based processors and devices. It allows radially differing hardware to be programmed using a common system, thus providing a first and necessary step towards the standardization of reconfigurable systems that results in a reduction of development time and cost.

  11. Glassy Chimeras Could Be Blind to Quantum Speedup: Designing Better Benchmarks for Quantum Annealing Machines

    Science.gov (United States)

    Katzgraber, Helmut G.; Hamze, Firas; Andrist, Ruben S.

    2014-04-01

    Recently, a programmable quantum annealing machine has been built that minimizes the cost function of hard optimization problems by, in principle, adiabatically quenching quantum fluctuations. Tests performed by different research teams have shown that, indeed, the machine seems to exploit quantum effects. However, experiments on a class of random-bond instances have not yet demonstrated an advantage over classical optimization algorithms on traditional computer hardware. Here, we present evidence as to why this might be the case. These engineered quantum annealing machines effectively operate coupled to a decohering thermal bath. Therefore, we study the finite-temperature critical behavior of the standard benchmark problem used to assess the computational capabilities of these complex machines. We simulate both random-bond Ising models and spin glasses with bimodal and Gaussian disorder on the D-Wave Chimera topology. Our results show that while the worst-case complexity of finding a ground state of an Ising spin glass on the Chimera graph is not polynomial, the finite-temperature phase space is likely rather simple because spin glasses on Chimera have only a zero-temperature transition. This means that benchmarking optimization methods using spin glasses on the Chimera graph might not be the best benchmark problems to test quantum speedup. We propose alternative benchmarks by embedding potentially harder problems on the Chimera topology. Finally, we also study the (reentrant) disorder-temperature phase diagram of the random-bond Ising model on the Chimera graph and show that a finite-temperature ferromagnetic phase is stable up to 19.85(15)% antiferromagnetic bonds. Beyond this threshold, the system only displays a zero-temperature spin-glass phase. Our results therefore show that a careful design of the hardware architecture and benchmark problems is key when building quantum annealing machines.

  12. Marginal chimera state at cross-frequency locking of pulse-coupled neural networks

    Science.gov (United States)

    Bolotov, M. I.; Osipov, G. V.; Pikovsky, A.

    2016-03-01

    We consider two coupled populations of leaky integrate-and-fire neurons. Depending on the coupling strength, mean fields generated by these populations can have incommensurate frequencies or become frequency locked. In the observed 2:1 locking state of the mean fields, individual neurons in one population are asynchronous with the mean fields, while in another population they have the same frequency as the mean field. These synchronous neurons form a chimera state, where part of them build a fully synchronized cluster, while other remain scattered. We explain this chimera as a marginal one, caused by a self-organized neutral dynamics of the effective circle map.

  13. Chimera states in a population of identical oscillators under planar cross-coupling

    Indian Academy of Sciences (India)

    C R Hens; A Mishra; P K Roy; A Sen; S K Dana

    2015-02-01

    We report the existence of chimera states in an assembly of identical nonlinear oscillators that are globally linked to each other in a simple planar cross-coupled form. The rotational symmetry breaking of the coupling term appears to be responsible for the emergence of these collective states that display a characteristic coexistence of coherent and incoherent behaviour. The finding, observed in both a collection of van der Pol oscillators and chaotic Rössler oscillators, further simplifies the existence criterion for chimeras, thereby broadens the range of their applicability to real-world situations.

  14. "American Chimera: The Ever-Present Domination of Whiteness, Patriarchy, and Capitalism…A Parable"

    Science.gov (United States)

    Montoya, Roberto; Matias, Cheryl E.; Nishi, Naomi W. M.; Sarcedo, Geneva L.

    2016-01-01

    In Greek mythology, the Chimera is a fire-breathing monster with three heads: one of a lion, one of a horned goat, and one of a powerful dragon. Of similar construction is the presence of three structures in US society, whiteness, patriarchy, and capitalism, which are overwhelmingly represented, valued, and espoused when examining areas of…

  15. CHIMERA: Clustering of Heterogeneous Disease Effects via Distribution Matching of Imaging Patterns.

    Science.gov (United States)

    Dong, Aoyan; Honnorat, Nicolas; Gaonkar, Bilwaj; Davatzikos, Christos

    2016-02-01

    Many brain disorders and diseases exhibit heterogeneous symptoms and imaging characteristics. This heterogeneity is typically not captured by commonly adopted neuroimaging analyses that seek only a main imaging pattern when two groups need to be differentiated (e.g., patients and controls, or clinical progressors and non-progressors). We propose a novel probabilistic clustering approach, CHIMERA, modeling the pathological process by a combination of multiple regularized transformations from normal/control population to the patient population, thereby seeking to identify multiple imaging patterns that relate to disease effects and to better characterize disease heterogeneity. In our framework, normal and patient populations are considered as point distributions that are matched by a variant of the coherent point drift algorithm. We explain how the posterior probabilities produced during the MAP optimization of CHIMERA can be used for clustering the patients into groups and identifying disease subtypes. CHIMERA was first validated on a synthetic dataset and then on a clinical dataset mixing 317 control subjects and patients suffering from Alzheimer's Disease (AD) and Parkison's Disease (PD). CHIMERA produced better clustering results compared to two standard clustering approaches. We further analyzed 390 T1 MRI scans from Alzheimer's patients. We discovered two main and reproducible AD subtypes displaying significant differences in cognitive performance.

  16. Incoherent chimera and glassy states in coupled oscillators with frustrated interactions

    Science.gov (United States)

    Choe, Chol-Ung; Ri, Ji-Song; Kim, Ryong-Son

    2016-09-01

    We suggest a site disorder model that describes the population of identical oscillators with quenched random interactions for both the coupling strength and coupling phase. We obtain the reduced equations for the suborder parameters, on the basis of Ott-Antonsen ansatz theory, and present a complete bifurcation analysis of the reduced system. New effects include the appearance of the incoherent chimera and glassy state, both of which are caused by heterogeneity of the coupling phases. In the incoherent chimera state, the system displays an exotic symmetry-breaking behavior in spite of the apparent structural symmetry where the oscillators for both of the two subpopulations are in a frustrated state, while the phase distribution for each subpopulation approaches a steady state that differs from each other. When the incoherent chimera undergoes Hopf bifurcation, the system displays a breathing incoherent chimera. The glassy state that occurs on a surface of three-dimensional parameter space exhibits a continuum of metastable states with zero value of the global order parameter. Explicit formulas are derived for the system's Hopf, saddle-node, and transcritical bifurcation curves, as well as the codimension-2 crossing points, including the Takens-Bogdanov point.

  17. Embryonic stem cells contribute to mouse chimeras in the absence of detectable cell fusion.

    Science.gov (United States)

    Kidder, Benjamin L; Oseth, Leann; Miller, Shanna; Hirsch, Betsy; Verfaillie, Catherine; Coucouvanis, Electra

    2008-06-01

    Embryonic stem (ES) cells are capable of differentiating into all embryonic and adult cell types following mouse chimera production. Although injection of diploid ES cells into tetraploid blastocysts suggests that tetraploid cells have a selective disadvantage in the developing embryo, tetraploid hybrid cells, formed by cell fusion between ES cells and somatic cells, have been reported to contribute to mouse chimeras. In addition, other examples of apparent stem cell plasticity have recently been shown to be the result of cell fusion. Here we investigate whether ES cells contribute to mouse chimeras through a cell fusion mechanism. Fluorescence in situ hybridization (FISH) analysis for X and Y chromosomes was performed on dissociated tissues from embryonic, neonatal, and adult wild-type, and chimeric mice to follow the ploidy distributions of cells from various tissues. FISH analysis showed that the ploidy distributions in dissociated tissues, notably the tetraploid cell number, did not differ between chimeric and wild-type tissues. To address the possibility that early cell fusion events are hidden by subsequent reductive divisions or other changes in cell ploidy, we injected Z/EG (lacZ/EGFP) ES cells into ACTB-cre blastocysts. Recombination can only occur as the result of cell fusion, and the recombined allele should persist through any subsequent changes in cell ploidy. We did not detect evidence of fusion in embryonic chimeras either by direct fluorescence microscopy for GFP or by PCR amplification of the recombined Z/EG locus on genomic DNA from ACTB-cre::Z/EG chimeric embryos. Our results argue strongly against cell fusion as a mechanism by which ES cells contribute to chimeras.

  18. Chronic graft-versus-host disease in the rat radiation chimera: I. clinical features, hematology, histology, and immunopathology in long-term chimeras

    Energy Technology Data Exchange (ETDEWEB)

    Beschorner, W.E.; Tutschka, P.J.; Santos, G.W.

    1982-04-01

    The clinical features, pathology, and immunopathology of chronic graft-versus-host disease (GVHD) developing in the long-term rat radiation chimera are described. At 6 to 12 months post-transplant, the previously stable ACI/LEW chimeras developed patchy to diffuse severe hair loss and thickened skin folds, and had microscopic features resembling scleroderma, Sjogren's syndrome, and chronic hepatitis. Skin histology showed dermal inflammation and acanthosis with atrophy of the appendages, with progression to dermal sclerosis. The liver revealed chronic hepatitis with bile duct injury and proliferation and periportal piecemeal necrosis. The tongue had considerable submucosal inflammation, muscular necrosis, and atrophy and arteritis. The serous salivary glands, lacrimal glands, and bronchi had lymphocytic inflammation and injury to duct, acinar, and mucosal columnar epithelium. The thymus had lymphocyte depletion of the medulla with prominent epithelium. The spleen and lymph nodes had poorly developed germinal centers but increased numbers of plasma cells. IgM was observed along the basement membrane and around the basal cells of the skin and tongue and along the basement membrane of the bile ducts. IgM was present also in the arteries of the tongue. Immunoglobulins eluted from the skin, cross-reacted with the bile duct epithelium and usually with both ACI and Lewis skin. Increased titers of speckled antinuclear antibodies were present in the serum of rats with chronic (GVHD). Chronic GVHD in the long-term rat radiation chimera is very similar to human chronic GVHD and is a potentially excellent model for autoimmune disorders including scleroderma, Sjorgren's syndrome, and chronic hepatitis.

  19. Chimera patterns induced by distance-dependent power-law coupling in ecological networks

    Science.gov (United States)

    Banerjee, Tanmoy; Dutta, Partha Sharathi; Zakharova, Anna; Schöll, Eckehard

    2016-09-01

    This paper reports the occurrence of several chimera patterns and the associated transitions among them in a network of coupled oscillators, which are connected by a long-range interaction that obeys a distance-dependent power law. This type of interaction is common in physics and biology and constitutes a general form of coupling scheme, where by tuning the power-law exponent of the long-range interaction the coupling topology can be varied from local via nonlocal to global coupling. To explore the effect of the power-law coupling on collective dynamics, we consider a network consisting of a realistic ecological model of oscillating populations, namely the Rosenzweig-MacArthur model, and show that the variation of the power-law exponent mediates transitions between spatial synchrony and various chimera patterns. We map the possible spatiotemporal states and their scenarios that arise due to the interplay between the coupling strength and the power-law exponent.

  20. Fast and reliable production, purification and characterization of heat-stable, bifunctional enzyme chimeras.

    Science.gov (United States)

    Neddersen, Mara; Elleuche, Skander

    2015-12-01

    Degradation of complex plant biomass demands a fine-regulated portfolio of glycoside hydrolases. The LE (LguI/Eco81I)-cloning approach was used to produce two enzyme chimeras CB and BC composed of an endoglucanase Cel5A (C) from the extreme thermophilic bacterium Fervidobacterium gondwanense and an archaeal β-glucosidase Bgl1 (B) derived from a hydrothermal spring metagenome. Recombinant chimeras and parental enzymes were produced in Escherichia coli and purified using a two-step affinity chromatography approach. Enzymatic properties revealed that both chimeras closely resemble the parental enzymes and physical mixtures, but Cel5A displayed lower temperature tolerance at 100°C when fused to Bgl1 independent of the conformational order. Moreover, the determination of enzymatic performances resulted in the detection of additive effects in case of BC fusion chimera. Kinetic measurements in combination with HPLC-mediated product analyses and site-directed mutation constructs indicated that Cel5A was strongly impaired when fused at the N-terminus, while activity was reduced to a slighter extend as C-terminal fusion partner. In contrast to these results, catalytic activity of Bgl1 at the N-terminus was improved 1.2-fold, effectively counteracting the slightly reduced activity of Cel5A by converting cellobiose into glucose. In addition, cellobiose exhibited inhibitory effects on Cel5A, resulting in a higher yield of cellobiose and glucose by application of an enzyme mixture (53.1%) compared to cellobiose produced from endoglucanase alone (10.9%). However, the overall release of cellobiose and glucose was even increased by catalytic action of BC (59.2%). These results indicate possible advantages of easily produced bifunctional fusion enzymes for the improved conversion of complex polysaccharide plant materials.

  1. Functional prokaryotic-eukaryotic chimera from the pentameric ligand-gated ion channel family.

    Science.gov (United States)

    Duret, Guillaume; Van Renterghem, Catherine; Weng, Yun; Prevost, Marie; Moraga-Cid, Gustavo; Huon, Christèle; Sonner, James M; Corringer, Pierre-Jean

    2011-07-19

    Pentameric ligand-gated ion channels (pLGICs), which mediate chemo-electric signal transduction in animals, have been recently found in bacteria. Despite clear sequence and 3D structure homology, the phylogenetic distance between prokaryotic and eukaryotic homologs suggests significant structural divergences, especially at the interface between the extracellular (ECD) and the transmembrane (TMD) domains. To challenge this possibility, we constructed a chimera in which the ECD of the bacterial protein GLIC is fused to the TMD of the human α1 glycine receptor (α1GlyR). Electrophysiology in Xenopus oocytes shows that it functions as a proton-gated ion channel, thereby locating the proton activation site(s) of GLIC in its ECD. Patch-clamp experiments in BHK cells show that the ion channel displays an anionic selectivity with a unitary conductance identical to that of the α1GlyR. In addition, pharmacological investigations result in transmembrane allosteric modulation similar to the one observed on α1GlyR. Indeed, the clinically active drugs propofol, four volatile general anesthetics, alcohols, and ivermectin all potentiate the chimera while they inhibit GLIC. Collectively, this work shows the compatibility between GLIC and α1GlyR domains and points to conservation of the ion channel and transmembrane allosteric regulatory sites in the chimera. This provides evidence that GLIC and α1GlyR share a highly homologous 3D structure. GLIC is thus a relevant model of eukaryotic pLGICs, at least from the anionic type. In addition, the chimera is a good candidate for mass production in Escherichia coli, opening the way for investigations of "druggable" eukaryotic allosteric sites by X-ray crystallography.

  2. Flexible and rapid construction of viral chimeras applied to hepatitis C virus.

    Science.gov (United States)

    McClure, C Patrick; Urbanowicz, Richard A; King, Barnabas J; Cano-Crespo, Sara; Tarr, Alexander W; Ball, Jonathan K

    2016-09-01

    A novel and broadly applicable strategy combining site-directed mutagenesis and DNA assembly for constructing seamless viral chimeras is described using hepatitis C virus (HCV) as an exemplar. Full-length HCV genomic cloning cassettes, which contained flexibly situated restriction endonuclease sites, were prepared via a single, site-directed mutagenesis reaction and digested to receive PCR-amplified virus envelope genes by In-Fusion cloning. Using this method, we were able to construct gene-shuttle cassettes for generation of cell culture-infectious JFH-1-based chimeras containing genotype 1-3 E1E2 genes. Importantly, using this method we also show that E1E2 clones that were not able to support cell entry in the HCV pseudoparticle assay did confer entry when shuttled into the chimeric cell culture chimera system. This method can be easily applied to other genes of study and other viruses and, as such, will greatly simplify reverse genetics studies of variable viruses.

  3. Human-animal chimera: a neuro driven discussion? Comparison of three leading European research countries.

    Science.gov (United States)

    Cabrera Trujillo, Laura Yenisa; Engel-Glatter, Sabrina

    2015-06-01

    Research with human-animal chimera raises a number of ethical concerns, especially when neural stem cells are transplanted into the brains of non-human primates (NHPs). Besides animal welfare concerns and ethical issues associated with the use of embryonic stem cells, the research is also regarded as controversial from the standpoint of NHPs developing cognitive or behavioural capabilities that are regarded as "unique" to humans. However, scientists are urging to test new therapeutic approaches for neurological diseases in primate models as they better mimic human physiology than all current animal models. As a response, various countries have issued reports on the topic. Our paper summarizes the ethical issues raised by research with human-animal brain chimeras and compares the relevant regulatory instruments and different recommendations issued in national reports from three important European research nations: Germany, Switzerland and the United Kingdom. We assess and discuss the focus and priorities set by the different reports, review various reasons for and perspectives on the importance of the brain in chimera research, and identify critical points in the reports that warrant further specification and debate.

  4. Formation of germline chimera Gaok chicken used circulation primordial germ cells (circulation PGCs fresh and thawed

    Directory of Open Access Journals (Sweden)

    Kostaman T

    2014-03-01

    Full Text Available Formation of germline chimeras by transfer of chicken primordial germ cells (PGCs is one of the effective techniques for preservation and regeneration of genetic resources in chickens. This study attempted to form germline chimeras of Gaok chicken buy purifying circulated PGCs of donor embryo before it is transferred to the recipient (White Leghorn chickens=WL and studied the ability of recipient embryo on survival in incubators, and hatchability. This study used 200 fertile eggs of Gaok and 90 fertile WL breed all of the eggs was incubated at 380C and 60% humidity in a portable incubator. PGCs-circulation of the blood collected Gaok embryos at stage 14-16 were taken from the dorsal aorta, and then purified by centrifugation method using nycodenz. PGCs-circulation results further purification frozen in liquid nitrogen before being transferred to the recipient embryo. The results showed that for the development of embryos transferred to the fresh circulation of PGCs-circulation as many as 25 cells can survive up to day 14, while one of the transferred of 50 and 100 cells into recipient embryos was hatched (10%. On the contrari recipient embryos that are transferred to the frozen PGCs-circulation the embryos development was shorter, and only survived until day 10th (treatment 25 cells, day 14th (treatment of 50 cells and day 17th (treatment of 100 cells. It is concluded that the amount of PGCs-circulation embryos transferred to the recipient is one factor that influence the success of the development germline chimeras.

  5. Plasmodium vivax Promiscuous T-Helper Epitopes Defined and Evaluated as Linear Peptide Chimera Immunogens

    Science.gov (United States)

    Caro-Aguilar, Ivette; Rodríguez, Alexandra; Calvo-Calle, J. Mauricio; Guzmán, Fanny; De la Vega, Patricia; Elkin Patarroyo, Manuel; Galinski, Mary R.; Moreno, Alberto

    2002-01-01

    Clinical trials of malaria vaccines have confirmed that parasite-derived T-cell epitopes are required to elicit consistent and long-lasting immune responses. We report here the identification and functional characterization of six T-cell epitopes that are present in the merozoite surface protein-1 of Plasmodium vivax (PvMSP-1) and bind promiscuously to four different HLA-DRB1∗ alleles. Each of these peptides induced lymphoproliferative responses in cells from individuals with previous P. vivax infections. Furthermore, linear-peptide chimeras containing the promiscuous PvMSP-1 T-cell epitopes, synthesized in tandem with the Plasmodium falciparum immunodominant circumsporozoite protein (CSP) B-cell epitope, induced high specific antibody titers, cytokine production, long-lasting immune responses, and immunoglobulin G isotype class switching in BALB/c mice. A linear-peptide chimera containing an allele-restricted P. falciparum T-cell epitope with the CSP B-cell epitope was not effective. Two out of the six promiscuous T-cell epitopes exhibiting the highest anti-peptide response also contain B-cell epitopes. Antisera generated against these B-cell epitopes recognize P. vivax merozoites in immunofluorescence assays. Importantly, the anti-peptide antibodies generated to the CSP B-cell epitope inhibited the invasion of P. falciparum sporozoites into human hepatocytes. These data and the simplicity of design of the chimeric constructs highlight the potential of multimeric, multistage, and multispecies linear-peptide chimeras containing parasite promiscuous T-cell epitopes for malaria vaccine development. PMID:12065487

  6. Embryonic stem cell/fibroblast hybrid cells with near-tetraploid karyotype provide high yield of chimeras.

    Science.gov (United States)

    Kruglova, A A; Kizilova, E A; Zhelezova, A I; Gridina, M M; Golubitsa, A N; Serov, O L

    2008-12-01

    Ten primary clones of hybrid cells were produced by the fusion of diploid embryonic stem (ES) cells, viz., line E14Tg2aSc4TP6.3 marked by green fluorescent protein (GFP), with diploid embryonic or adult fibroblasts derived from DD/c mice. All the hybrid clones had many characteristics similar to those of ES cells and were positive for GFP. Five hybrid clones having ploidy close to tetraploidy (over 80% of cells had 76-80 chromosomes) were chosen for the generation of chimeras via injection into C57BL blastocysts. These hybrid clones also contained microsatellites marking all ES cell and fibroblast chromosomes judging from microsatellite analysis. Twenty chimeric embryos at 11-13 days post-conception were obtained after injection of hybrid cells derived from two of three clones. Many embryos showed a high content of GFP-positive descendents of the tested hybrid cells. Twenty one adult chimeras were generated by the injection of hybrid cells derived from three clones. The contribution of GFP-labeled hybrid cells was significant and comparable with that of diploid E14Tg2aSc4TP6.3 cells. Cytogenetic and microsatellite analyses of cell cultures derived from chimeric embryos or adults indicated that the initial karyotype of the tested hybrid cells remained stable during the development of the chimeras, i.e., the hybrid cells were mainly responsible for the generation of the chimeras. Thus, ES cell/fibroblast hybrid cells with near-tetraploid karyotype are able to generate chimeras at a high rate, and many adult chimeras contain a high percentage of descendants of the hybrid cells.

  7. Resistance to infection with Eimeria vermiformis in mouse radiation chimeras is determined by donor bone-marrow cells

    Energy Technology Data Exchange (ETDEWEB)

    Joysey, H.S.; Wakelin, D.; Rose, M.E.

    1988-05-01

    The course of infection with Eimeria vermiformis was determined in BALB/b, BALB/c, and C57BL/10ScSn (B10) mice and in radiation chimeras prepared from the H-2-compatible BALB/b and B10 mice. The BALB strains, irrespective of H-2 haplotype, were resistant, the B10 mice were susceptible, and in the chimeras infection was characterized by the genotype of the donated bone-marrow cells and not by the phenotype of the recipient. Thus, the genetic control of relative resistance or susceptibility to infection with this parasite is expressed through bone-marrow-derived cells.

  8. Ethical questions concerning research on human embryos, embryonic stem cells and chimeras.

    Science.gov (United States)

    Bobbert, Monika

    2006-12-01

    Research using human embryos and embryonic stem cells is viewed as important for various reasons. Apart from questions concerning legal regulations, numerous ethical objections are raised pertaining to the use of surplus embryos from reproductive medicine as well as the creation of embryos and stem cells through cloning. In the hopes of avoiding ethical problems, alternatives have been proposed including the extraction of egg cells from "dead" embryos derived from in vitro fertilization procedures, the extraction of pluripotent stem cells from blastocysts, technologies such as "altered nuclear transfer" (ANT) and "oocyte-assisted reprogramming" (ANT-OAR) as well as parthenogenesis. Initial ethical assessments show that certain questions pertaining to such strategies have remained unanswered. Furthermore, with the help of new or more differentiated biotechnological procedures, it is possible to create chimeras and hybrids in which human and non-human cells are combined. Human-animal chimeras, in which gametes or embryonic tissue have been mixed with embryonic or adult stem cells, demonstrate a different "quality" and "degree of penetration" from those produced in previous experiments. Not only does this have consequences regarding questions of patentability, this situation also raises fundamental questions concerning the human being's self image, the concept of person, identity and species and the moral rights and duties that are connected with such concepts. There is a need for legal regulation, on the national as well as the international level.

  9. Transient scaling and resurgence of chimera states in networks of Boolean phase oscillators

    Science.gov (United States)

    Rosin, David P.; Rontani, Damien; Haynes, Nicholas D.; Schöll, Eckehard; Gauthier, Daniel J.

    2014-09-01

    We study networks of nonlocally coupled electronic oscillators that can be described approximately by a Kuramoto-like model. The experimental networks show long complex transients from random initial conditions on the route to network synchronization. The transients display complex behaviors, including resurgence of chimera states, which are network dynamics where order and disorder coexists. The spatial domain of the chimera state moves around the network and alternates with desynchronized dynamics. The fast time scale of our oscillators (on the order of 100ns) allows us to study the scaling of the transient time of large networks of more than a hundred nodes, which has not yet been confirmed previously in an experiment and could potentially be important in many natural networks. We find that the average transient time increases exponentially with the network size and can be modeled as a Poisson process in experiment and simulation. This exponential scaling is a result of a synchronization rate that follows a power law of the phase-space volume.

  10. Fluorescent protein-scorpion toxin chimera is a convenient molecular tool for studies of potassium channels.

    Science.gov (United States)

    Kuzmenkov, Alexey I; Nekrasova, Oksana V; Kudryashova, Kseniya S; Peigneur, Steve; Tytgat, Jan; Stepanov, Alexey V; Kirpichnikov, Mikhail P; Grishin, Eugene V; Feofanov, Alexey V; Vassilevski, Alexander A

    2016-09-21

    Ion channels play a central role in a host of physiological and pathological processes and are the second largest target for existing drugs. There is an increasing need for reliable tools to detect and visualize particular ion channels, but existing solutions suffer from a number of limitations such as high price, poor specificity, and complicated protocols. As an alternative, we produced recombinant chimeric constructs (FP-Tx) consisting of fluorescent proteins (FP) fused with potassium channel toxins from scorpion venom (Tx). In particular, we used two FP, eGFP and TagRFP, and two Tx, OSK1 and AgTx2, to create eGFP-OSK1 and RFP-AgTx2. We show that these chimeras largely retain the high affinity of natural toxins and display selectivity to particular ion channel subtypes. FP-Tx are displaced by other potassium channel blockers and can be used as an imaging tool in ion channel ligand screening setups. We believe FP-Tx chimeras represent a new efficient molecular tool for neurobiology.

  11. Generating Porcine Chimeras Using Inner Cell Mass Cells and Parthenogenetic Preimplantation Embryos

    Science.gov (United States)

    Nakano, Kazuaki; Watanabe, Masahito; Matsunari, Hitomi; Matsuda, Taisuke; Honda, Kasumi; Maehara, Miki; Kanai, Takahiro; Hayashida, Gota; Kobayashi, Mirina; Kuramoto, Momoko; Arai, Yoshikazu; Umeyama, Kazuhiro; Fujishiro, Shuh-hei; Mizukami, Yoshihisa; Nagaya, Masaki; Hanazono, Yutaka; Nagashima, Hiroshi

    2013-01-01

    Background The development and validation of stem cell therapies using induced pluripotent stem (iPS) cells can be optimized through translational research using pigs as large animal models, because pigs have the closest characteristics to humans among non-primate animals. As the recent investigations have been heading for establishment of the human iPS cells with naïve type characteristics, it is an indispensable challenge to develop naïve type porcine iPS cells. The pluripotency of the porcine iPS cells can be evaluated using their abilities to form chimeras. Here, we describe a simple aggregation method using parthenogenetic host embryos that offers a reliable and effective means of determining the chimera formation ability of pluripotent porcine cells. Methodology/Significant Principal Findings In this study, we show that a high yield of chimeric blastocysts can be achieved by aggregating the inner cell mass (ICM) from porcine blastocysts with parthenogenetic porcine embryos. ICMs cultured with morulae or 4–8 cell-stage parthenogenetic embryos derived from in vitro-matured (IVM) oocytes can aggregate to form chimeric blastocysts that can develop into chimeric fetuses after transfer. The rate of production of chimeric blastocysts after aggregation with host morulae (20/24, 83.3%) was similar to that after the injection of ICMs into morulae (24/29, 82.8%). We also found that 4–8 cell-stage embryos could be used; chimeric blastocysts were produced with a similar efficiency (17/26, 65.4%). After transfer into recipients, these blastocysts yielded chimeric fetuses at frequencies of 36.0% and 13.6%, respectively. Conclusion/Significance Our findings indicate that the aggregation method using parthenogenetic morulae or 4–8 cell-stage embryos offers a highly reproducible approach for producing chimeric fetuses from porcine pluripotent cells. This method provides a practical and highly accurate system for evaluating pluripotency of undifferentiated cells, such

  12. EpCAM Aptamer-siRNA Chimera Targets and Regress Epithelial Cancer.

    Directory of Open Access Journals (Sweden)

    Nithya Subramanian

    Full Text Available Epithelial cell adhesion molecule (EpCAM, a cancer stem cell (CSC marker is over expressed in epithelial cancers and in retinoblastoma (RB. We fabricated an EpCAM targeting aptamer-siRNA chimera and investigated its anti-tumor property and EpCAM intracellular domain (EpICD mediated signaling in epithelial cancer. The anti-tumor efficacy of EpCAM aptamer-siEpCAM chimera (EpApt-siEp was evaluated by qPCR, northern and Western blotting in WERI-Rb1- RB cell line, primary RB tumor cells and in MCF7- breast cancer cell line. Anti-tumor activity of EpApt-siEp was studied in vivo using epithelial cancer (MCF7 mice xenograft model. The mechanism and pathways involved in the anti-tumor activity was further studied using protein arrays and qPCR. EpApt-siEp chimera was processed in vitro by dicer enzyme. Treatment of the WERI-Rb1 and MCF7 cells with EpApt-siEp revealed statistically significant down regulation of EpCAM expression (P<0.005 and concomitant reduction in cellular proliferation. In primary RB cells cultured from RB tumors, EpApt-siEp silenced EpCAM, significantly inhibited (P<0.01 cell proliferation and induced cytotoxicity. Knockdown of EpICD expressed in RB primary tumors led to repression of pluripotency markers, SOX2, OCT4, NANOG, and CD133. In vivo studies showed complete tumor growth regression without any toxicity in animals (P<0.001 and tumor tissues showed significant downregulation (P<0.05 of EpCAM, MRP1, ABCG2, stathmin, survivin and upregulation of ATM (P<0.05 leading to apoptosis by intrinsic pathway with minor alteration in cytokines. Our results revealed that EpApt-siEp potentially eradicated EpCAM positive cancer cells through CSC marker suppression and apoptosis, while sparing normal EpCAM negative adjacent cells.

  13. Chimera distribution amplitudes for the pion and the longitudinally polarized $\\rho$-meson

    CERN Document Server

    Stefanis, N G

    2016-01-01

    Using QCD sum rules with nonlocal condensates, we show that the distribution amplitude of the longitudinally polarized $\\rho$-meson may have a shorttailed platykurtic profile in close analogy to our recently proposed platykurtic distribution amplitude for the pion. Such a chimera distribution de facto amalgamates the broad unimodal profile of the distribution amplitude, obtained with a Dyson-Schwinger equations-based computational scheme, with the suppressed tails characterizing the bimodal distribution amplitudes derived from QCD sum rules with nonlocal condensates. We argue that pattern formation, emerging from the collective synchronization of coupled oscillators, can provide a single theoretical scaffolding to study unimodal and bimodal distribution amplitudes of light mesons without recourse to particular computational schemes and the reasons for them.

  14. Monsters, dreams and madness: Commentary on 'The arms of the chimeras'.

    Science.gov (United States)

    Reis, Bruce

    2016-04-01

    Considering Freudian and Post-Freudian approaches to the intersubjective Beatrice Ithier puts the work of Michel de M'Uzan and Thomas Ogden in comparison. To this comparison I add a consideration of the work of Christopher Bollas. The highly creative clinical approaches these three theorists take is shown to be informed by their elaborations of the Freudian notion of unconscious communication and by new approaches to the issue of identity. Attention is paid to differentiating traumatic from fanciful chimeras; and to the experience of the analyst undergoing the sorts of transformations requisite to entering this psychic space marked by fluid exchanges of being and becoming, wherein analyst becomes patient, new subjects are created through shared dreams, and through which monsters appear.

  15. Chimera distribution amplitudes for the pion and the longitudinally polarized ρ-meson

    Energy Technology Data Exchange (ETDEWEB)

    Stefanis, N.G., E-mail: stefanis@tp2.ruhr-uni-bochum.de [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Pimikov, A.V., E-mail: pimikov@theor.jinr.ru [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna (Russian Federation); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

    2016-01-15

    Using QCD sum rules with nonlocal condensates, we show that the distribution amplitude of the longitudinally polarized ρ-meson may have a shorttailed platykurtic profile in close analogy to our recently proposed platykurtic distribution amplitude for the pion. Such a chimera distribution de facto amalgamates the broad unimodal profile of the distribution amplitude, obtained with a Dyson–Schwinger equations-based computational scheme, with the suppressed tails characterizing the bimodal distribution amplitudes derived from QCD sum rules with nonlocal condensates. We argue that pattern formation, emerging from the collective synchronization of coupled oscillators, can provide a single theoretical scaffolding to study unimodal and bimodal distribution amplitudes of light mesons without recourse to particular computational schemes and the reasons for them.

  16. 2D and 3D Core-Collapse Supernovae Simulation Results Obtained with the CHIMERA Code

    CERN Document Server

    Bruenn, S W; Hix, W R; Blondin, J M; Marronetti, P; Messer, O E B; Dirk, C J; Yoshida, S

    2010-01-01

    Much progress in realistic modeling of core-collapse supernovae has occurred recently through the availability of multi-teraflop machines and the increasing sophistication of supernova codes. These improvements are enabling simulations with enough realism that the explosion mechanism, long a mystery, may soon be delineated. We briefly describe the CHIMERA code, a supernova code we have developed to simulate core-collapse supernovae in 1, 2, and 3 spatial dimensions. We then describe the results of an ongoing suite of 2D simulations initiated from a 12, 15, 20, and 25 solar mass progenitor. These have all exhibited explosions and are currently in the expanding phase with the shock at between 5,000 and 20,000 km. We also briefly describe an ongoing simulation in 3 spatial dimensions initiated from the 15 solar mass progenitor.

  17. Novel type of chimera spiral waves arising from decoupling of a diffusible component

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Xiaodong; Yang, Tao; Liu, Yang; Zhao, Yuemin; Gao, Qingyu, E-mail: epstein@brandeis.edu, E-mail: gaoqy@cumt.edu.cn [College of Chemical Engineering, China University of Mining and Technology, Xuzhou 221008 (China); Epstein, Irving R., E-mail: epstein@brandeis.edu, E-mail: gaoqy@cumt.edu.cn [Department of Chemistry and Volen Center for Complex Systems, MS 015, Brandeis University, Waltham, Massachusetts 02454-9110 (United States)

    2014-07-14

    Spiral waves composed of coherent traveling waves surrounding a core containing stochastically distributed stationary areas are found in numerical simulations of a three-variable reaction-diffusion system with one diffusible species. In the spiral core, diffusion of this component (w) mediates transitions between dynamic states of the subsystem formed by the other two components, whose dynamics is more rapid than that of w. Diffusive coupling between adjacent sites can be “on” or “off” depending on the subsystem state. The incoherent structures in the spiral core are produced by this decoupling of the slow diffusive component from the fast non-diffusing subsystem. The phase diagram reveals that the region of incoherent behavior in chimera spirals grows drastically, leading to modulation and breakup of the spirals, in the transition zones between 1{sup n-1} and 1{sup n} local mixed-mode oscillations.

  18. TRAPS, CHIMERAS AND PATHWAYS: THREE APPROACHES OF ART IN CONTEMPORARY ANTHROPOLOGY

    Directory of Open Access Journals (Sweden)

    André Demarchi

    2009-12-01

    Full Text Available Based upon the concepts of traps, chimera and pathways proposed by Alfred Gell, Carlo Severi and Els Lagrou respectively, this bibliographic essay presents the characteristics, similarities and specificities of three approaches on art in contemporary anthropology. The work focuses on the ruptures created by these approaches, concerning the symbolic analysis that has long dominated the anthropological art studies. Breaking away from the conception of art as a symbolic language, the studies we analyzed emphasized, in different ways, the cognitive action of art in native contexts, privileging categories such as agency, efficacy, counter-intuitiveness, and presentification. In the conclusion, we demonstrate how these categories are applied to Amerindian Art through the work of Els Lagrou on Cashinahua Art.

  19. Cross-reactivity of hypervariable region 1 chimera of hepatitis C virus

    Institute of Scientific and Technical Information of China (English)

    Bing-Shui Xiu; Shi-Gan Ling; Xiao-Guo Song; He-Qiu Zhang; Kun Chen; Cui-Xia Zhu

    2003-01-01

    AIM: To analyze the amino acid sequences of hypervariable region 1 (HVR1) of HCV isolates in China and to construct a combinatorial chimeric HVR1 protein having a very broad high cross-reactivity. METHODS: All of the published HVR1 sequences from China were collected and processed with a computer program.Several representative HVR1's sequences were formulated based on a consensus profile and homology within certain subdivision. A few reported HVR1 mimotope sequences were also included for a broader representation. All of them were cloned and expressed in E.coli. The cross-reactivity of the purified recombinant HVR1 antigens was tested by ELISA with a panel of sera from HCV infected patients in China.Some of them were further ligated together to form a combinatorial HVR1 chimera. RESULTS: Altogether 12 HVR1s were selected and expressed in E. coli and purified to homogeneity. All of these purified antigens showed some cross-reactivity with sera in a 27 HCV positive panel. Recombinant HVR1s of No. 1, 2, 4, and 8# showing broad cross-reactivities and complementarity with each other, were selected for the ligation elements. The chimera containing these 4 HVR1s was highly expressed in E. coli. The purified chimeric antigen could react not only with all the HCV antibody positive sera in the panel but also with 90/91 sera of HCV -infected patients. CONCLUSION: The chimeric antigen was shown to have a broad cross-reactivity. It may be helpful for solving the problem caused by high variability of HCV, and in the efforts for a novel vaccine against the virus.

  20. Tissue distribution of cells derived from the area opaca in heterospecific quail-chick blastodermal chimeras.

    Science.gov (United States)

    Karagenç, Levent; Sandikci, Mustafa

    2010-01-01

    The objective of the current study was to determine the tissue distribution of cells derived from the area opaca in heterospecific quail-chick blastodermal chimeras. Quail-chick chimeras were constructed by transferring dissociated cells from the area opaca of the stage X-XII (EG&K) quail embryo into the subgerminal cavity of the unincubated chick blastoderm. The distribution of quail cells in embryonic as well as extra-embryonic tissues of the recipient embryo were examined using the QCPN monoclonal antibody after 6 days of incubation in serial sections taken at 100-mum intervals. Data gathered in the present study demonstrated that, when introduced into the subgerminal cavity of a recipient embryo, cells of the area opaca are able to populate not only extra-embryonic structures such as the amnion and the yolk sac, but also various embryonic tissues derived from the ectoderm and less frequently the mesoderm. Ectodermal chimerism was confined mainly to the head region and was observed in tissues derived from the neural ectoderm and the surface ectoderm, including the optic cup, diencephalon and lens. Although the possibility of random incorporation of transplanted cells into these embryonic structures cannot be excluded, these results would suggest that area opaca, a peripheral ring of cells in the avian embryo destined to form the extra-embryonic ectoderm and endoderm of the yolk sac, might harbor cells that have the potential to give rise to various cell types in the recipient chick embryo, including those derived from the surface ectoderm and neural ectoderm.

  1. Bacterial membrane activity of a-peptide/b-peptoid chimeras: Influence of amino acid composition and chain length on the activity against different bacterial strains

    DEFF Research Database (Denmark)

    Hein-Kristensen, Line; Knapp, Kolja M; Franzyk, Henrik;

    2011-01-01

    , and this was parallel by the largest reduction in number of viable bacteria. CONCLUSION: We found that chain length but not type of cationic amino acid influenced the antibacterial activity of a series of synthetic α-peptide/β-peptoid chimeras. The synthetic chimeras exert their killing effect by permeabilization......BACKGROUND: Characterization and use of antimicrobial peptides (AMPs) requires that their mode of action is determined. The interaction of membrane-active peptides with their target is often established using model membranes, however, the actual permeabilization of live bacterial cells...... acid only had a minor effect on MIC values, whereas chain length had a profound influence on activity. All chimeras were less active against Serratia marcescens (MICs above 46 μM). The chimeras were bactericidal and induced leakage of ATP from Staphylococcus aureus and S. marcescens with similar time...

  2. Generation of mouse chimeras with high contribution of tetraploid embryonic stem cells and embryonic stem cell-fibroblast hybrid cells.

    Science.gov (United States)

    Matveeva, Natalia M; Kizilova, Elena A; Serov, Oleg L

    2015-01-01

    The in vitro long-term cultivation of embryonic stem (ES) cells derived from pre-implantation embryos offers the unique possibility of combining ES cells with pre-implantation embryos to generate chimeras, thus facilitating the creation of a bridge between in vitro and in vivo investigations. Genomic manipulation using ES cells and homologous recombination is one of the most outstanding scientific achievements, resulting in the generation of animals with desirable genome modifications. As such, the generation of ES cells with different ploidy via cell fusion also deserves much attention because this approach allows for the production of chimeras that contain somatic cells with various ploidy. Therefore, this is a powerful tool that can be used to study the role of polyploidy in the normal development of mammals.

  3. Antigenic characteristics of rhinovirus chimeras designed in silico for enhanced presentation of HIV-1 gp41 epitopes [corrected].

    Science.gov (United States)

    Lapelosa, Mauro; Arnold, Gail Ferstandig; Gallicchio, Emilio; Arnold, Eddy; Levy, Ronald M

    2010-04-02

    The development of an effective AIDS vaccine remains the most promising long-term strategy to combat human immunodeficiency virus (HIV)/AIDS. Here, we report favorable antigenic characteristics of vaccine candidates isolated from a combinatorial library of human rhinoviruses displaying the ELDKWA epitope of the gp41 glycoprotein of HIV-1. The design principles of this library emerged from the application of molecular modeling calculations in conjunction with our knowledge of previously obtained ELDKWA-displaying chimeras, including knowledge of a chimera with one of the best 2F5-binding characteristics obtained to date. The molecular modeling calculations identified the energetic and structural factors affecting the ability of the epitope to assume conformations capable of fitting into the complementarity determining region of the ELDKWA-binding, broadly neutralizing human mAb 2F5. Individual viruses were isolated from the library following competitive immunoselection and were tested using ELISA and fluorescence quenching experiments. Dissociation constants obtained using both techniques revealed that some of the newly isolated chimeras bind 2F5 with greater affinity than previously identified chimeric rhinoviruses. Molecular dynamics simulations of two of these same chimeras confirmed that their HIV inserts were partially preorganized for binding, which is largely responsible for their corresponding gains in binding affinity. The study illustrates the utility of combining structure-based experiments with computational modeling approaches for improving the odds of selecting vaccine component designs with preferred antigenic characteristics. The results obtained also confirm the flexibility of HRV as a presentation vehicle for HIV epitopes and the potential of this platform for the development of vaccine components against AIDS.

  4. Evaluation of PCR-generated chimeras, mutations, and heteroduplexes with 16S rRNA gene-based cloning.

    Science.gov (United States)

    Qiu, X; Wu, L; Huang, H; McDonel, P E; Palumbo, A V; Tiedje, J M; Zhou, J

    2001-02-01

    To evaluate PCR-generated artifacts (i.e., chimeras, mutations, and heteroduplexes) with the 16S ribosomal DNA (rDNA)-based cloning approach, a model community of four species was constructed from alpha, beta, and gamma subdivisions of the division Proteobacteria as well as gram-positive bacterium, all of which could be distinguished by HhaI restriction digestion patterns. The overall PCR artifacts were significantly different among the three Taq DNA polymerases examined: 20% for Z-Taq, with the highest processitivity; 15% for LA-Taq, with the highest fidelity and intermediate processitivity; and 7% for the conventionally used DNA polymerase, AmpliTaq. In contrast to the theoretical prediction, the frequency of chimeras for both Z-Taq (8.7%) and LA-Taq (6.2%) was higher than that for AmpliTaq (2.5%). The frequencies of chimeras and of heteroduplexes for Z-Taq were almost three times higher than those of AmpliTaq. The total PCR artifacts increased as PCR cycles and template concentrations increased and decreased as elongation time increased. Generally the frequency of chimeras was lower than that of mutations but higher than that of heteroduplexes. The total PCR artifacts as well as the frequency of heteroduplexes increased as the species diversity increased. PCR artifacts were significantly reduced by using AmpliTaq and fewer PCR cycles (fewer than 20 cycles), and the heteroduplexes could be effectively removed from PCR products prior to cloning by polyacrylamide gel purification or T7 endonuclease I digestion. Based upon these results, an optimal approach is proposed to minimize PCR artifacts in 16S rDNA-based microbial community studies.

  5. A Direct Mapping of Max k-SAT and High Order Parity Checks to a Chimera Graph

    Science.gov (United States)

    Chancellor, N.; Zohren, S.; Warburton, P. A.; Benjamin, S. C.; Roberts, S.

    2016-11-01

    We demonstrate a direct mapping of max k-SAT problems (and weighted max k-SAT) to a Chimera graph, which is the non-planar hardware graph of the devices built by D-Wave Systems Inc. We further show that this mapping can be used to map a similar class of maximum satisfiability problems where the clauses are replaced by parity checks over potentially large numbers of bits. The latter is of specific interest for applications in decoding for communication. We discuss an example in which the decoding of a turbo code, which has been demonstrated to perform near the Shannon limit, can be mapped to a Chimera graph. The weighted max k-SAT problem is the most general class of satisfiability problems, so our result effectively demonstrates how any satisfiability problem may be directly mapped to a Chimera graph. Our methods faithfully reproduce the low energy spectrum of the target problems, so therefore may also be used for maximum entropy inference.

  6. The ethics of killing human/great-ape chimeras for their organs: a reply to Shaw et al.

    Science.gov (United States)

    Palacios-González, César

    2016-06-01

    The aim of this paper is to critically examine David Shaw, Wybo Dondorp, and Guido de Wert's arguments in favour of the procurement of human organs from human/nonhuman-primate chimeras, specifically from great-ape/human chimeras. My main claim is that their arguments fail and are in need of substantial revision. To prove this I first introduce the topic, and then reconstruct Shaw et al.'s position and arguments. Next, I show that Shaw et al.: (1) failed to properly apply the subsidiarity and proportionality principles; (2) neglected species overlapping cases in their ethical assessment; (3) ignored the ethics literature on borderline persons; and (4) misunderstood McMahan's two-tiered moral theory. These mistakes render an important part of their conclusions either false or problematic to the point that they would no longer endorse them. Finally I will briefly mention a possible multipolar solution to the human organ shortage problem that would reduce the need for chimeras' organs.

  7. Contribution of cells derived from the area pellucida to extraembryonic mesodermal cell lineages in heterospecific quail chick blastodermal chimeras.

    Science.gov (United States)

    Karagenç, Levent; Sandikci, Mustafa

    2013-01-01

    The current study has two main objectives: first, to determine if cells derived from the area pellucida are able to populate extraembryonic membranes, and second, to determine if donor cells have the potential to differentiate to endothelial (EC) and hematopoietic cells (HC) in the yolk sac and allantois, the two extraembryonic membranes functioning as hematopoietic organs in the avian embryo. To this end, quail chick chimeras were constructed by transferring dissociated cells from the areae pellucidae of the stage X-XII (EG&K) quail embryo into the subgerminal cavity of the unincubated chick blastoderm. The distribution of quail cells in the allantois, yolk sac, amnion, and chorion of resulting putative chimeras was examined using quail cell-specific antibody against a perinuclear antigen (QCPN) after 6 days of incubation. The presence of EC, HC, and smooth muscle cells among the QCPN(+) donor cells was examined using QH-1, a quail-specific marker identifying HC and EC and an anti-α-smooth muscle actin antibody. Evidence gathered in the present study demonstrates that quail cells derived from the areae pellucidae are able to populate all of the extraembryonic membranes of resulting heterospecific quail chick chimeras and, most importantly, give rise to HC, EC, and smooth muscle cells, all of the three main mesodermal lineages derived from the posterior mesoderm both in the yolk sac and allantois.

  8. Clonal and territorial development of the pancreas as revealed by eGFP-labelled mouse chimeras.

    Science.gov (United States)

    Eberhard, Daniel; Jockusch, Harald

    2010-10-01

    The clonal structure of the pancreas was analysed in neonatal and adult mouse chimeras in which one partner displayed cell patches expressing green fluorescent protein (eGFP). Coherent growth during pancreatic histogenesis was suggested by the presence of large eGFP-labelled acinar clusters rather than a scattered distribution of individual labelled acinar cells. The adult chimeric pancreas contained monophenotypic acini, whereas surprisingly 5% of acini in neonates were polyclonal. Monophenotypic acini presumably arose by coherent expansion leading to large 3D patches and may not be monoclonal. Islets of Langerhans were oligoclonal at both ages investigated. The proportion of eGFP positive cells within islets did not correlate with that of the surrounding acinar tissue indicating clonal independence of islets from their neighbourhood. The patterns observed argue against a secondary contribution of blood-borne progenitor/stem cells to the acinar compartment during tissue turnover. The different clonal origins of acini and islets are integrated into a model of pancreatic histogenesis.

  9. Mouse embryos and chimera cloned from neural cells in the postnatal cerebral cortex.

    Science.gov (United States)

    Makino, Hatsune; Yamazaki, Yukiko; Hirabayashi, Takahiro; Kaneko, Ryosuke; Hamada, Shun; Kawamura, Yoshimi; Osada, Tomoharu; Yanagimachi, Ryuzo; Yagi, Takeshi

    2005-01-01

    Cloning of mice has been achieved by transferring nuclei of various types of somatic cell nuclei into enucleated oocytes. However, all attempts to produce live cloned offspring using the nuclei of neurons from adult cerebral cortex have failed. Previously we obtained cloned mice using the nuclei of neural cells collected from fetal cerebral cortex. Here, we attempted to generate cloned mice using differentiated neurons from the cerebral cortex of postnatal (day 0-4) mice. Although we were unable to obtain live cloned pups, many fetuses reached day 10.5 days of development. These fetuses showed various abnormalities such as spherical omission of the neuroepithelium, collapsed lumen of neural tube, and aberrant expressions of marker proteins of neurons. We produced chimeric mice in which some hair cells and kidney cells were originated from differentiated neurons. In chimeric fetuses, LacZ-positive donor cells were in all three germ cell layers. However, chimeras with large contribution of donor-derived cells were not obtained. These results indicate that nuclei of differentiated neurons have lost their developmental totipotency. In other words, the conventional nuclear transfer technique does not allow nuclei of differentiated neurons to undergo complete genomic reprogramming required for normal embryonic development.

  10. Human-animal chimeras: ethical issues about farming chimeric animals bearing human organs.

    Science.gov (United States)

    Bourret, Rodolphe; Martinez, Eric; Vialla, François; Giquel, Chloé; Thonnat-Marin, Aurélie; De Vos, John

    2016-06-29

    Recent advances in stem cells and gene engineering have paved the way for the generation of interspecies chimeras, such as animals bearing an organ from another species. The production of a rat pancreas by a mouse has demonstrated the feasibility of this approach. The next step will be the generation of larger chimeric animals, such as pigs bearing human organs. Because of the dramatic organ shortage for transplantation, the medical needs for such a transgressive practice are indisputable. However, there are serious technical barriers and complex ethical issues that must be discussed and solved before producing human organs in animals. The main ethical issues are the risks of consciousness and of human features in the chimeric animal due to a too high contribution of human cells to the brain, in the first case, or for instance to limbs, in the second. Another critical point concerns the production of human gametes by such chimeric animals. These worst-case scenarios are obviously unacceptable and must be strictly monitored by careful risk assessment, and, if necessary, technically prevented. The public must be associated with this ethical debate. Scientists and physicians have a critical role in explaining the medical needs, the advantages and limits of this potential medical procedure, and the ethical boundaries that must not be trespassed. If these prerequisites are met, acceptance of such a new, borderline medical procedure may prevail, as happened before for in-vitro fertilization or preimplantation genetic diagnosis.

  11. Spatially organized dynamical states in chemical oscillator networks: synchronization, dynamical differentiation, and chimera patterns.

    Directory of Open Access Journals (Sweden)

    Mahesh Wickramasinghe

    Full Text Available Dynamical processes in many engineered and living systems take place on complex networks of discrete dynamical units. We present laboratory experiments with a networked chemical system of nickel electrodissolution in which synchronization patterns are recorded in systems with smooth periodic, relaxation periodic, and chaotic oscillators organized in networks composed of up to twenty dynamical units and 140 connections. The reaction system formed domains of synchronization patterns that are strongly affected by the architecture of the network. Spatially organized partial synchronization could be observed either due to densely connected network nodes or through the 'chimera' symmetry breaking mechanism. Relaxation periodic and chaotic oscillators formed structures by dynamical differentiation. We have identified effects of network structure on pattern selection (through permutation symmetry and coupling directness and on formation of hierarchical and 'fuzzy' clusters. With chaotic oscillators we provide experimental evidence that critical coupling strengths at which transition to identical synchronization occurs can be interpreted by experiments with a pair of oscillators and analysis of the eigenvalues of the Laplacian connectivity matrix. The experiments thus provide an insight into the extent of the impact of the architecture of a network on self-organized synchronization patterns.

  12. T and B lymphocytes in the marmoset: a natural haemopoietic chimera

    Energy Technology Data Exchange (ETDEWEB)

    Niblack, G.D.; Gengozian, N.

    1976-01-01

    The thymus-derived (T) lymphocyte and bone marrow-derived (B) lymphocyte populations of the marmoset were characterized using specific cell surface markers. Approximately 85% of the thymocytes formed rosettes with neuraminidase-treated sheep erythrocytes (E/sub n/). The percentage (approximately 69%) of peripheral blood lymphocytes (PBL) forming rosettes with E/sub n/ was the same as that which stained with fluorescently labelled goat anti-marmoset thymocyte serum (ATS). These two assays identified the same cell population since treatment of cells with ATS and complement resulted in a concomitant decrease in E/sub n/ rosette formation. Marmoset PBL also formed rosettes with human erythrocytes sensitized with antibody and complement (HEAC); since the percentage (approximately 20%) HEAC rosette was the same as that of cells stained with fluorescently labelled goat anti-marmoset IgG, these cells were considered to be B cells. A small percentage of cells (aproximately 1.5%) possessed both types of receptors. The mean percentages of T and B cells present in PBL of single-born, presumably non-chimeric animals, were the same as that of isosexual and heterosexual chimeras.

  13. Aerodynamic study of sounding rocket flows using Chimera and patched multiblock meshes

    Directory of Open Access Journals (Sweden)

    João Alves de Oliveira Neto

    2011-01-01

    Full Text Available Aerodynamic flow simulations over a typical sounding rocket are presented in this paper. The work is inserted in the effort of developing computational tools necessary to simulate aerodynamic flows over configurations of interest for Instituto de Aeronáutica e Espaço of Departamento de Ciência e Tecnologia Aeroespacial. Sounding rocket configurations usually require fairly large fins and, quite frequently, have more than one set of fins. In order to be able to handle such configurations, the present paper presents a novel methodology which combines both Chimera and patched multiblock grids in the discretization of the computational domain. The flows of interest are modeled using the 3-D Euler equations and the work describes the details of discretization procedure, which uses a finite difference approach for structure, body-conforming, multiblock grids. The method is used to calculate the aerodynamics of a sounding rocket vehicle. The results indicate that the present approach can be a powerful aerodynamic analysis and design tool.

  14. Magnetorotational dynamo chimeras. The missing link to turbulent accretion disk dynamo models?

    Science.gov (United States)

    Riols, A.; Rincon, F.; Cossu, C.; Lesur, G.; Ogilvie, G. I.; Longaretti, P.-Y.

    2017-02-01

    In Keplerian accretion disks, turbulence and magnetic fields may be jointly excited through a subcritical dynamo mechanisminvolving magnetorotational instability (MRI). This dynamo may notably contribute to explaining the time-variability of various accreting systems, as high-resolution simulations of MRI dynamo turbulence exhibit statistical self-organization into large-scale cyclic dynamics. However, understanding the physics underlying these statistical states and assessing their exact astrophysical relevance is theoretically challenging. The study of simple periodic nonlinear MRI dynamo solutions has recently proven useful in this respect, and has highlighted the role of turbulent magnetic diffusion in the seeming impossibility of a dynamo at low magnetic Prandtl number (Pm), a common regime in disks. Arguably though, these simple laminar structures may not be fully representative of the complex, statistically self-organized states expected in astrophysical regimes. Here, we aim at closing this seeming discrepancy by reporting the numerical discovery of exactly periodic, yet semi-statistical "chimeral MRI dynamo states" which are the organized outcome of a succession of MRI-unstable, non-axisymmetric dynamical stages of different forms and amplitudes. Interestingly, these states, while reminiscent of the statistical complexity of turbulent simulations, involve the same physical principles as simpler laminar cycles, and their analysis further confirms the theory that subcritical turbulent magnetic diffusion impedes the sustainment of an MRI dynamo at low Pm. Overall, chimera dynamo cycles therefore offer an unprecedented dual physical and statistical perspective on dynamos in rotating shear flows, which may prove useful in devising more accurate, yet intuitive mean-field models of time-dependent turbulent disk dynamos. Movies associated to Fig. 1 are available at http://www.aanda.org

  15. CONSTRUCTION OF HU-PBL/SCID CHIMERAS AND DEVELOPMENT OF EBV-RELATED LYMPHOMAS

    Institute of Scientific and Technical Information of China (English)

    Run-liang Gan; Ke Lan; Zhi-hua Yin; Li-jiang Wang; Ying Song; Kai-tai Yao

    2005-01-01

    Objective To construct hu-PBL/SCID chimeras and to investigate the development of lymphoma and oncogenicity of the Epstein-Barr virus (EBV).Mtehods Human peripheral blood lymphocytes (PBLs) were isolated from healthy adult donors and transplanted intraperitoneally into severe combined immunodeficient (SCID) mice. Mice with hu-PBL engraftment from healthy EBV seronegative donors were injected intraperitoneally with EBV-containing supematant from suspension culture of B95-8 cell line (active infection), whereas mice receiving lymphocytes from healthy EBV seropositive donors were not re-infected with B95-8 derived EBV (latent infection). Pathological examination and molecular analysis were performed on experimental animals and induced neoplasms.Results In the early stage of this experiment, 12 mice died of acute graft-versus-host disease, mortality was 34.3%(12/35 mice) with an average life span of 17.5 days. In 19 survival hu-PBL/SCID chimeric recipients from 12 healthy donors,tumor incidence was 84.2% (16/19 mice). The average survival time of tumor-bearing mice was 65.5 days. EBV-related neoplasms in SCID mice were nodular tumors with aggressive and fatal features. Histological morphology of tumors exhibited diffuse large cell lymphomas. Immunohistochemistry revealed that LCA (CD45) and L26 (CD20) were positive, but both PS1 (CD3) and UCHL-1 (CD45RO) were negative, and EBV products ZEBRA, LMP1, and EBNA2 were expressed in a small number of tumor cells. EB virus particles were seen in the nuclei of some tumor cells by electron microscopy, and EBV DNA could be amplified in the tumor tissues by PCR. In situ hybridization indicated that the nuclei of tumor cells contained human-specific Alu sequence.Conclusions EBV-induced tumors were human B-cell malignant lymphomas. We obtained direct causative evidence dealing with EBV-associated tumor deriving from normal human cells.

  16. Functional assignment by Chimera construction of the domain affecting heterotropic activation of deoxyadenosine kinase from Lactobacillus acidophilus R-26.

    Science.gov (United States)

    Guo, S; Ives, D H

    1998-10-01

    The heterodimeric subunits of deoxyadenosine kinase (dAK)-deoxyguanosine kinase (dGK) from Lactobacillus acidophilus R-26 exhibit contrasting conformations manifested in the nearly unidirectional heterotropic activation of dAK when dGK binds deoxyguanosine. This is mediated, in part, by the conserved Ras switch I-like sequence (residues 153-161) [Guo et al. (1997) J. Biol. Chem. 272, 6890-6897]. In an attempt to identify domains differentiating the specificities of dAK and dGK, we constructed several chimeras splicing heterodimeric dAK within this region. In Chimera-III, dAK residues 120-170 were replaced by the homologous section of dGK. dAK activity was elevated 40%, but although it retained its original specificity and Km values, it could no longer be activated by deoxyguanosine. Moreover, both the activated dAK and the "dAK" of Chimera-III exhibited (i) an increased Ks for the leading substrate ATP-Mg2+, suggesting the formation of intermediate enzyme species along their respective kinetic pathways, and (ii) broadened and lower pH optima for the dAK activities. These observations further indicate the importance of dAK residues 120-170, including the Ras-like segment, in catalysis and heterotropic activation. The other conformational properties of dAK (e.g. self-inactivity and MgATP being the leading substrate) were unaltered by this substitution, thus localizing the responsible domains even further upstream.

  17. Immunogenicity of a West Nile virus DIII-cholera toxin A2/B chimera after intranasal delivery.

    Science.gov (United States)

    Tinker, Juliette K; Yan, Jie; Knippel, Reece J; Panayiotou, Panos; Cornell, Kenneth A

    2014-04-22

    West Nile virus (WNV) causes potentially fatal neuroinvasive disease and persists at endemic levels in many parts of the world. Despite advances in our understanding of WNV pathogenesis, there remains a significant need for a human vaccine. The domain III (DIII) region of the WNV envelope protein contains epitopes that are the target of neutralizing antibodies. We have constructed a chimeric fusion of the non-toxic cholera toxin (CT) CTA2/B domains to DIII for investigation as a novel mucosally-delivered WNV vaccine. Purification and assembly of the chimera, as well as receptor-binding and antigen delivery, were verified by western blot, GM1 ELISA and confocal microscopy. Groups of BALB/c mice were immunized intranasally with DIII-CTA2/B, DIII, DIII mixed with CTA2/B, or CTA2/B control, and boosted at 10 days. Analysis of serum IgG after 14 and 45 days revealed that mucosal immunization with DIII-CTA2/B induced significant DIII-specific humoral immunity and drove isotype switching to IgG2a. The DIII-CTA2/B chimera also induced antigen-specific IgM and IgA responses. Bactericidal assays indicate that the DIII-CTA2/B immunized mice produced DIII-specific antibodies that can trigger complement-mediated killing. A dose escalation resulted in increased DIII-specific serum IgG titers on day 45. DIII antigen alone, in the absence of adjuvant, also induced significant systemic responses after intranasal delivery. Our results indicate that the DIII-CTA2/B chimera is immunogenic after intranasal delivery and merits further investigation as a novel WNV vaccine candidate.

  18. Particle identification method in the CsI(Tl) scintillator used for the CHIMERA 4 pi detector

    CERN Document Server

    Alderighi, M; Basssini, R; Berceanu, I; Blicharska, J; Boiano, C; Borderie, B; Bougault, R; Bruno, M; Cali, C; Cardella, G; Cavallaro, S; D'Agostino, M; D'andrea, M; Dayras, R; De Filippo, E; Fichera, F; Geraci, E; Giustolisi, F; Grzeszczuk, A; Guardone, N; Guazzoni, P; Guinet, D; Iacono-Manno, M; Kowalski, S; La Guidara, E; Lanchais, A L; Lanzalone, G; Lanzanò, G; Le Neindre, N; Li, S; Maiolino, C; Majka, Z; Manfredi, G; Nicotra, D; Paduszynski, T; Pagano, A; Papa, M; Petrovici, C M; Piasecki, E; Pirrone, S; Politi, G; Pop, A; Porto, F; Rivet, M F; Rosato, E; Sacca, G; Sechi, G; Simion, V; Sperduto, M L; Steckmeyer, J C; Trifiró, A; Trimarchi, M; Urso, S; Vannini, G; Vigilante, M; Wilczynski, J; Wu, H; Xiao, Z; Zetta, L; Zipper, W

    2002-01-01

    The charged particle identification obtained by the analysis of signals coming from the CsI(Tl) detectors of the CHIMERA 4 pi heavy-ion detector is presented. A simple double-gate integration method, with the use of the cyclotron radiofrequency as reference time, results in low thresholds for isotopic particle identification. The dependence of the identification quality on the gate generation timing is discussed. Isotopic identification of light ions up to Beryllium is clearly seen. For the first time also the identification of Z=5 particles is observed. The identification of neutrons interacting with CsI(Tl) by (n,alpha) and (n,gamma) reactions is also discussed.

  19. Imperfectly synchronized states and chimera states in two interacting populations of nonlocally coupled Stuart-Landau oscillators.

    Science.gov (United States)

    Premalatha, K; Chandrasekar, V K; Senthilvelan, M; Lakshmanan, M

    2016-07-01

    We investigate the emergence of different kinds of imperfectly synchronized states and chimera states in two interacting populations of nonlocally coupled Stuart-Landau oscillators. We find that the complete synchronization in population I and existence of solitary oscillators which escape from the synchronized group in population II lead to imperfectly synchronized states for sufficiently small values of nonisochronicity parameter. Interestingly, upon increasing the strength of this parameter further there occurs an onset of mixed imperfectly synchronized states where the solitary oscillators occur from both the populations. Synchronized oscillators from both the populations are locked to a common average frequency. In both cases of imperfectly synchronized states, synchronized oscillators exhibit periodic motion while the solitary oscillators are quasiperiodic in nature. In this region, for spatially prepared initial conditions, we can observe the mixed chimera states where the coexistence of synchronized and desynchronized oscillations occur from both the populations. On the other hand, imperfectly synchronized states are not always stable, and they can drift aperiodically due to instability caused by an increase of nonisochronicity parameter. We observe that these states are robust to the introduction of frequency mismatch between the two populations.

  20. New screening software shows that most recent large 16S rRNA gene clone libraries contain chimeras.

    Science.gov (United States)

    Ashelford, Kevin E; Chuzhanova, Nadia A; Fry, John C; Jones, Antonia J; Weightman, Andrew J

    2006-09-01

    A new computer program, called Mallard, is presented for screening entire 16S rRNA gene libraries of up to 1,000 sequences for chimeras and other artifacts. Written in the Java computer language and capable of running on all major operating systems, the program provides a novel graphical approach for visualizing phylogenetic relationships among 16S rRNA gene sequences. To illustrate its use, we analyzed most of the large libraries of cloned bacterial 16S rRNA gene sequences submitted to the public repository during 2005. Defining a large library as one containing 100 or more sequences of 1,200 bases or greater, we screened 25 of the 28 libraries and found that all but three contained substantial anomalies. Overall, 543 anomalous sequences were found. The average anomaly content per clone library was 9.0%, 4% higher than that previously estimated for the public repository overall. In addition, 90.8% of anomalies had characteristic chimeric patterns, a rise of 25.4% over that found previously. One library alone was found to contain 54 chimeras, representing 45.8% of its content. These figures far exceed previous estimates of artifacts within public repositories and further highlight the urgent need for all researchers to adequately screen their libraries prior to submission. Mallard is freely available from our website at http://www.cardiff.ac.uk/biosi/research/biosoft/.

  1. CHIMERA: a wide-field, multi-color, high-speed photometer at the prime focus of the Hale telescope

    CERN Document Server

    Harding, Leon K; Milburn, Jennifer; Gardner, Paul; Konidaris, Nick; Singh, Navtej; Shao, Michael; Sandhu, Jagmit; Kyne, Gillian; Schlichting, Hilke E

    2016-01-01

    The Caltech HIgh-speed Multi-color camERA (CHIMERA) is a new instrument that has been developed for use at the prime focus of the Hale 200-inch telescope. Simultaneous optical imaging in two bands is enabled by a dichroic beam splitter centered at 567 nm, with Sloan u' and g' bands available on the blue arm and Sloan r', i' and z_s' bands available on the red arm. Additional narrow-band filters will also become available as required. An Electron Multiplying CCD (EMCCD) detector is employed for both optical channels, each capable of simultaneously delivering sub-electron effective read noise under multiplication gain and frame rates of up to 26 fps full frame (several 1000 fps windowed), over a fully corrected 5 x 5 arcmin field of view. CHIMERA was primarily developed to enable the characterization of the size distribution of sub-km Kuiper Belt Objects via stellar occultation, a science case that motivates the frame-rate, the simultaneous multi-color imaging and the wide field of view of the instrument. In ad...

  2. An Activin A/BMP2 chimera displays bone healing properties superior to those of BMP2

    Science.gov (United States)

    Yoon, Byung-Hak; Esquivies, Luis; Ahn, Chihoon; Gray, Peter C.; Ye, Sang-kyu; Kwiatkowski, Witek; Choe, Senyon

    2014-01-01

    Recombinant Bone Morphogenetic Protein 2 (rhBMP2) has been used clinically to treat bone fractures in human patients. However, the high doses of rhBMP2 required for a therapeutic response can cause undesirable side effects. Here, we demonstrate that a novel Activin A/BMP2 (AB2) chimera, AB204, promotes osteogenesis and bone healing much more potently and effectively than rhBMP2. Remarkably, 1 month of AB204 treatment completely heals tibial and calvarial defects of critical size in mice at a concentration 10-fold lower than a dose of rhBMP2 that only partially heals the defect. We determine the structure of AB204 to 2.3 Å that reveals a distinct BMP2-like fold in which the Activin A sequence segments confer insensitivity to the BMP2 antagonist Noggin and an affinity for the Activin/BMP type II receptor ActRII that is 100-fold greater than that of BMP2. The structure also led to our identification of a single Activin A-derived amino acid residue which when mutated to the corresponding BMP2 residue resulted in a significant increase in the affinity of AB204 for its type I receptor BMPRIa and a further enhancement in AB204's osteogenic potency. Together, these findings demonstrate that rationally designed AB2 chimeras can provide BMP2 substitutes with enhanced potency for treating non-union bone fractures. PMID:24692083

  3. Strain-transcending immune response generated by chimeras of the malaria vaccine candidate merozoite surface protein 2

    Science.gov (United States)

    Krishnarjuna, Bankala; Andrew, Dean; MacRaild, Christopher A.; Morales, Rodrigo A. V.; Beeson, James G.; Anders, Robin F.; Richards, Jack S.; Norton, Raymond S.

    2016-01-01

    MSP2 is an intrinsically disordered protein that is abundant on the merozoite surface and essential to the parasite Plasmodium falciparum. Naturally-acquired antibody responses to MSP2 are biased towards dimorphic sequences within the central variable region of MSP2 and have been linked to naturally-acquired protection from malaria. In a phase IIb study, an MSP2-containing vaccine induced an immune response that reduced parasitemias in a strain-specific manner. A subsequent phase I study of a vaccine that contained both dimorphic forms of MSP2 induced antibodies that exhibited functional activity in vitro. We have assessed the contribution of the conserved and variable regions of MSP2 to the generation of a strain-transcending antibody response by generating MSP2 chimeras that included conserved and variable regions of the 3D7 and FC27 alleles. Robust anti-MSP2 antibody responses targeting both conserved and variable regions were generated in mice, although the fine specificity and the balance of responses to these regions differed amongst the constructs tested. We observed significant differences in antibody subclass distribution in the responses to these chimeras. Our results suggest that chimeric MSP2 antigens can elicit a broad immune response suitable for protection against different strains of P. falciparum. PMID:26865062

  4. SCHEMA computational design of virus capsid chimeras: calibrating how genome packaging, protection, and transduction correlate with calculated structural disruption.

    Science.gov (United States)

    Ho, Michelle L; Adler, Benjamin A; Torre, Michael L; Silberg, Jonathan J; Suh, Junghae

    2013-12-20

    Adeno-associated virus (AAV) recombination can result in chimeric capsid protein subunits whose ability to assemble into an oligomeric capsid, package a genome, and transduce cells depends on the inheritance of sequence from different AAV parents. To develop quantitative design principles for guiding site-directed recombination of AAV capsids, we have examined how capsid structural perturbations predicted by the SCHEMA algorithm correlate with experimental measurements of disruption in seventeen chimeric capsid proteins. In our small chimera population, created by recombining AAV serotypes 2 and 4, we found that protection of viral genomes and cellular transduction were inversely related to calculated disruption of the capsid structure. Interestingly, however, we did not observe a correlation between genome packaging and calculated structural disruption; a majority of the chimeric capsid proteins formed at least partially assembled capsids and more than half packaged genomes, including those with the highest SCHEMA disruption. These results suggest that the sequence space accessed by recombination of divergent AAV serotypes is rich in capsid chimeras that assemble into 60-mer capsids and package viral genomes. Overall, the SCHEMA algorithm may be useful for delineating quantitative design principles to guide the creation of libraries enriched in genome-protecting virus nanoparticles that can effectively transduce cells. Such improvements to the virus design process may help advance not only gene therapy applications but also other bionanotechnologies dependent upon the development of viruses with new sequences and functions.

  5. An activin A/BMP2 chimera, AB204, displays bone-healing properties superior to those of BMP2.

    Science.gov (United States)

    Yoon, Byung-Hak; Esquivies, Luis; Ahn, Chihoon; Gray, Peter C; Ye, Sang-Kyu; Kwiatkowski, Witek; Choe, Senyon

    2014-09-01

    Recombinant bone morphogenetic protein 2 (rhBMP2) has been used clinically to treat bone fractures in human patients. However, the high doses of rhBMP2 required for a therapeutic response can cause undesirable side effects. Here, we demonstrate that a novel Activin A/BMP2 (AB2) chimera, AB204, promotes osteogenesis and bone healing much more potently and effectively than rhBMP2. Remarkably, 1 month of AB204 treatment completely heals tibial and calvarial defects of critical size in mice at a concentration 10-fold lower than a dose of rhBMP2 that only partially heals the defect. We determine the structure of AB204 to 2.3 Å that reveals a distinct BMP2-like fold in which the Activin A sequence segments confer insensitivity to the BMP2 antagonist Noggin and an affinity for the Activin/BMP type II receptor ActRII that is 100-fold greater than that of BMP2. The structure also led to our identification of a single Activin A-derived amino acid residue, which, when mutated to the corresponding BMP2 residue, resulted in a significant increase in the affinity of AB204 for its type I receptor BMPRIa and a further enhancement in AB204's osteogenic potency. Together, these findings demonstrate that rationally designed AB2 chimeras can provide BMP2 substitutes with enhanced potency for treating non-union bone fractures.

  6. In-cell aggregation of a polyglutamine-containing chimera is a multistep process initiated by the flanking sequence.

    Science.gov (United States)

    Ignatova, Zoya; Thakur, Ashwani K; Wetzel, Ronald; Gierasch, Lila M

    2007-12-14

    Toxicity in amyloid diseases is intimately linked to the nature of aggregates, with early oligomeric species believed to be more cytotoxic than later fibrillar aggregates. Yet mechanistic understanding of how aggregating species evolve with time is currently lacking. We have explored the aggregation process of a chimera composed of a globular protein (cellular retinoic acid-binding protein, CRABP) and huntingtin exon 1 with polyglutamine tracts either above (Q53) or below (Q20) the pathological threshold using Escherichia coli cells as a model intracellular environment. Previously we showed that fusion of the huntingtin exon 1 sequence with >40Q led to structural perturbation and decreased stability of CRABP (Ignatova, Z., and Gierasch, L. M. (2006) J. Biol. Chem. 281, 12959-12967). Here we report that the Q53 chimera aggregates in cells via a multistep process: early stage aggregates are spherical and detergent-soluble, characteristics of prefibrillar aggregates, and appear to be dominated structurally by CRABP, in that they can promote aggregation of a CRABP variant but not oligoglutamine aggregation, and the CRABP domain is relatively sequestered based on its protection from proteolysis. Late stage aggregates appear to be dominated by polyGln; they are fibrillar, detergent-resistant, capable of seeding aggregation of oligoglutamine but not the CRABP variant, and show relative protection of the polyglutamine-exon1 domain from proteolysis. These results point to an evolution of the dominant sequences in intracellular aggregates and may provide molecular insight into origins of toxic prefibrillar aggregates.

  7. Generation of germ-line chimera zebrafish using primordial germ cells isolated from cultured blastomeres and cryopreserved embryoids.

    Science.gov (United States)

    Kawakami, Yutaka; Goto-Kazeto, Rie; Saito, Taiju; Fujimoto, Takafumi; Higaki, Shogo; Takahashi, Yoshiyuki; Arai, Katsutoshi; Yamaha, Etsuro

    2010-01-01

    Primordial germ cells (PGCs) are the only cells in developing embryos with the potential to transmit genetic information to the next generation. In our previous study, a single PGC transplanted into a host differentiated into fertile gametes and produced germ-line chimeras of cyprinid fish, including zebrafish. In this study, we aimed to induce germ-line chimeras by transplanting donor PGCs from various sources (normal embryos at different stages, dissociated blastomeres, embryoids, or embryoids cryopreserved by vitrification) into host blastulae, and compare the migration rates of the PGCs towards the gonadal ridge. Isolated, cultured blastomeres not subject to mesodermal induction were able to differentiate into PGCs that retained their motility. Moreover, these PGCs successfully migrated towards the gonadal ridge of the host and formed viable gametes. Motility depended on developmental stage and culture duration: PGCs obtained at earlier developmental stages and with shorter cultivation periods showed an increased rate of migration to the gonadal ridge. Offspring were obtained from natural spawning between normal females and chimeric males. These results provide the basis for new methods of gene preservation in zebrafish.

  8. Infectious RNA transcripts from Ross River virus cDNA clones and the construction and characterization of defined chimeras with Sindbis virus.

    Science.gov (United States)

    Kuhn, R J; Niesters, H G; Hong, Z; Strauss, J H

    1991-06-01

    We have constructed a full-length cDNA clone of the virulent T48 strain of Ross River virus, a member of the alphavirus genus. Infectious RNA can be transcribed from this clone using SP6 or T7 RNA polymerase. The rescued virus has properties indistinguishable from those of the T48 strain of Ross River virus. We have used this clone, together with a full-length cDNA clone of Sindbis virus, to construct chimeric plasmids in which the 5' and the 3' nontranslated regions of the Sindbis and Ross River genomes were exchanged. The nontranslated regions of the two viral genomes differ in both size and sequence although they maintain specific conserved sequence elements. Virus was recovered from all four chimeras. Chimeras containing heterologous 3' nontranslated regions had replicative efficiencies equal to those of the parents. In contrast, the chimeras containing heterologous 5' nontranslated regions were defective in RNA synthesis and virus production, and the severity of the defect was dependent upon the host. Replication of a virus containing a heterologous 5' nontranslated region may be inefficient due to the formation of defective protein-RNA complexes, whereas, the presumptive complexes formed between host or virus proteins and the 3' nontranslated region to promote RNA synthesis appear to function normally in the chimeras.

  9. Chronic Exposure to Androgenic-Anabolic Steroids Exacerbates Axonal Injury and Microgliosis in the CHIMERA Mouse Model of Repetitive Concussion.

    Directory of Open Access Journals (Sweden)

    Dhananjay R Namjoshi

    Full Text Available Concussion is a serious health concern. Concussion in athletes is of particular interest with respect to the relationship of concussion exposure to risk of chronic traumatic encephalopathy (CTE, a neurodegenerative condition associated with altered cognitive and psychiatric functions and profound tauopathy. However, much remains to be learned about factors other than cumulative exposure that could influence concussion pathogenesis. Approximately 20% of CTE cases report a history of substance use including androgenic-anabolic steroids (AAS. How acute, chronic, or historical AAS use may affect the vulnerability of the brain to concussion is unknown. We therefore tested whether antecedent AAS exposure in young, male C57Bl/6 mice affects acute behavioral and neuropathological responses to mild traumatic brain injury (TBI induced with the CHIMERA (Closed Head Impact Model of Engineered Rotational Acceleration platform. Male C57Bl/6 mice received either vehicle or a cocktail of three AAS (testosterone, nandrolone and 17α-methyltestosterone from 8-16 weeks of age. At the end of the 7th week of treatment, mice underwent two closed-head TBI or sham procedures spaced 24 h apart using CHIMERA. Post-repetitive TBI (rTBI behavior was assessed for 7 d followed by tissue collection. AAS treatment induced the expected physiological changes including increased body weight, testicular atrophy, aggression and downregulation of brain 5-HT1B receptor expression. rTBI induced behavioral deficits, widespread axonal injury and white matter microgliosis. While AAS treatment did not worsen post-rTBI behavioral changes, AAS-treated mice exhibited significantly exacerbated axonal injury and microgliosis, indicating that AAS exposure can alter neuronal and innate immune responses to concussive TBI.

  10. Three dimensional visualization and fractal analysis of mosaic patches in rat chimeras: cell assortment in liver, adrenal cortex and cornea.

    Science.gov (United States)

    Iannaccone, Stephen; Zhou, Yue; Walterhouse, David; Taborn, Greg; Landini, Gabriel; Iannaccone, Philip

    2012-01-01

    The production of organ parenchyma in a rapid and reproducible manner is critical to normal development. In chimeras produced by the combination of genetically distinguishable tissues, mosaic patterns of cells derived from the combined genotypes can be visualized. These patterns comprise patches of contiguously similar genotypes and are different in different organs but similar in a given organ from individual to individual. Thus, the processes that produce the patterns are regulated and conserved. We have previously established that mosaic patches in multiple tissues are fractal, consistent with an iterative, recursive growth model with simple stereotypical division rules. Fractal dimensions of various tissues are consistent with algorithmic models in which changing a single variable (e.g. daughter cell placement after division) switches the mosaic pattern from islands to stripes of cells. Here we show that the spiral pattern previously observed in mouse cornea can also be visualized in rat chimeras. While it is generally held that the pattern is induced by stem cell division dynamics, there is an unexplained discrepancy in the speed of cellular migration and the emergence of the pattern. We demonstrate in chimeric rat corneas both island and striped patterns exist depending on the age of the animal. The patches that comprise the pattern are fractal, and the fractal dimension changes with the age of the animal and indicates the constraint in patch complexity as the spiral pattern emerges. The spiral patterns are consistent with a loxodrome. Such data are likely to be relevant to growth and cell division in organ systems and will help in understanding how organ parenchyma are generated and maintained from multipotent stem cell populations located in specific topographical locations within the organ. Ultimately, understanding algorithmic growth is likely to be essential in achieving organ regeneration in vivo or in vitro from stem cell populations.

  11. Three dimensional visualization and fractal analysis of mosaic patches in rat chimeras: cell assortment in liver, adrenal cortex and cornea.

    Directory of Open Access Journals (Sweden)

    Stephen Iannaccone

    Full Text Available The production of organ parenchyma in a rapid and reproducible manner is critical to normal development. In chimeras produced by the combination of genetically distinguishable tissues, mosaic patterns of cells derived from the combined genotypes can be visualized. These patterns comprise patches of contiguously similar genotypes and are different in different organs but similar in a given organ from individual to individual. Thus, the processes that produce the patterns are regulated and conserved. We have previously established that mosaic patches in multiple tissues are fractal, consistent with an iterative, recursive growth model with simple stereotypical division rules. Fractal dimensions of various tissues are consistent with algorithmic models in which changing a single variable (e.g. daughter cell placement after division switches the mosaic pattern from islands to stripes of cells. Here we show that the spiral pattern previously observed in mouse cornea can also be visualized in rat chimeras. While it is generally held that the pattern is induced by stem cell division dynamics, there is an unexplained discrepancy in the speed of cellular migration and the emergence of the pattern. We demonstrate in chimeric rat corneas both island and striped patterns exist depending on the age of the animal. The patches that comprise the pattern are fractal, and the fractal dimension changes with the age of the animal and indicates the constraint in patch complexity as the spiral pattern emerges. The spiral patterns are consistent with a loxodrome. Such data are likely to be relevant to growth and cell division in organ systems and will help in understanding how organ parenchyma are generated and maintained from multipotent stem cell populations located in specific topographical locations within the organ. Ultimately, understanding algorithmic growth is likely to be essential in achieving organ regeneration in vivo or in vitro from stem cell populations.

  12. A Chimera Containing CD4+ and CD8+ T-Cell Epitopes of the Leishmania donovani Nucleoside Hydrolase (NH36) Optimizes Cross-Protection against Leishmania amazonesis Infection

    Science.gov (United States)

    Alves-Silva, Marcus Vinícius; Nico, Dirlei; Morrot, Alexandre; Palatnik, Marcos; Palatnik-de-Sousa, Clarisa B.

    2017-01-01

    The Leishmania donovani nucleoside hydrolase (NH36) and NH A34480 of Leishmania amazonensis share 93% of sequence identity. In mice, the NH36 induced protection against visceral leishmaniasis is mediated by a CD4+ T cell response against its C-terminal domain (F3). Besides this CD4+ Th1 response, prevention and cure of L. amazonensis infection require also additional CD8+ and regulatory T-cell responses to the NH36 N-terminal (F1 domain). We investigated if mice vaccination with F1 and F3 domains cloned in tandem, in a recombinant chimera, with saponin, optimizes the vaccine efficacy against L. amazonensis infection above the levels promoted by the two admixed domains or by each domain independently. The chimera induced the highest IgA, IgG, and IgG2a anti-NH36 antibody, IDR, IFN-γ, and IL-10 responses, while TNF-α was more secreted by mice vaccinated with F3 or all F3-contaning vaccines. Additionally, the chimera and the F1 vaccine also induced the highest proportions of CD4+ and CD8+ T cells secreting IL-2, TNF-α, or IFN-γ alone, TNF-α in combination with IL-2 or IFN-γ, and of CD4+ multifunctional cells secreting IL-2, TNF-α, and IFN-γ. Correlating with the immunological results, the strongest reductions of skin lesions sizes were determined by the admixed domains (80%) and by the chimera (84%), which also promoted the most pronounced and significant reduction of the parasite load (99.8%). Thus, the epitope presentation in a recombinant chimera optimizes immunogenicity and efficacy above the levels induced by the independent or admixed F1 and F3 domains. The multiparameter analysis disclosed that the Th1-CD4+ T helper response induced by the chimera is mainly directed against its FRYPRPKHCHTQVA epitope. Additionally, the YPPEFKTKL epitope of F1 induced the second most important CD4+ T cell response, and, followed by the DVAGIVGVPVAAGCT, FMLQILDFYTKVYE, and ELLAITTVVGNQ sequences, also the most potent CD8+ T cell responses and IL-10 secretion. Remarkably

  13. Genes encoding chimeras of Neurospora crassa erg-3 and human TM7SF2 proteins fail to complement Neurospora and yeast sterol C-14 reductase mutants

    Indian Academy of Sciences (India)

    A Prakash; Durgadas P Kasbekar

    2002-03-01

    The human gene TM7SF2 encodes a polypeptide (SR-1) with high sequence similarity to sterol C-14 reductase, a key sterol biosynthetic enzyme in fungi, plants and mammals. In Neurospora and yeast this enzyme is encoded by the erg-3 and erg24 genes respectively. In an effort to demonstrate sterol C-14 reductase activity for SR-1 we constructed six recombinant genes coding for chimeras of the Neurospora erg-3 and SR-1 protein sequences and tested them for complementation of the Neurospora erg-3 mutant. To our surprise, all the chimeras failed to complement erg-3. A few of the chimeric proteins were also tested against the yeast erg24 mutant, but again there was no complementation. We discuss some reasons that might account for these unexpected findings.

  14. Niemann-Pick C1 (NPC1/NPC1-like1 Chimeras Define Sequences Critical for NPC1’s Function as a Filovirus Entry Receptor

    Directory of Open Access Journals (Sweden)

    Esther Ndungo

    2012-10-01

    Full Text Available We recently demonstrated that Niemann-Pick C1 (NPC1, a ubiquitous 13-pass cellular membrane protein involved in lysosomal cholesterol transport, is a critical entry receptor for filoviruses. Here we show that Niemann-Pick C1-like1 (NPC1L1, an NPC1 paralog and hepatitis C virus entry factor, lacks filovirus receptor activity. We exploited the structural similarity between NPC1 and NPC1L1 to construct and analyze a panel of chimeras in which NPC1L1 sequences were replaced with cognate sequences from NPC1. Only one chimera, NPC1L1 containing the second luminal domain (C of NPC1 in place of its own, bound to the viral glycoprotein, GP. This engineered protein mediated authentic filovirus infection nearly as well as wild-type NPC1, and more efficiently than did a minimal NPC1 domain C-based receptor recently described by us. A reciprocal chimera, NPC1 containing NPC1L1’s domain C, was completely inactive. Remarkably, an intra-domain NPC1L1-NPC1 chimera bearing only a ~130-amino acid N–terminal region of NPC1 domain C could confer substantial viral receptor activity on NPC1L1. Taken together, these findings account for the failure of NPC1L1 to serve as a filovirus receptor, highlight the central role of the luminal domain C of NPC1 in filovirus entry, and reveal the direct involvement of N–terminal domain C sequences in NPC1’s function as a filovirus receptor.

  15. Rearrangement and junctional-site sequence analyses of T-cell receptor gamma genes in intestinal intraepithelial lymphocytes from murine athymic chimeras.

    Science.gov (United States)

    Whetsell, M; Mosley, R L; Whetsell, L; Schaefer, F V; Miller, K S; Klein, J R

    1991-12-01

    The molecular organization of rearranged T-cell receptor (TCR) gamma genes intraepithelial lymphocytes (IEL) was studied in athymic radiation chimeras and was compared with the organization of gamma gene rearrangements in IEL from thymus-bearing animals by polymerase chain reaction and by sequence analyses of DNA spanning the junction of the variable (V) and joining (J) genes. In both thymus-bearing mice and athymic chimeras, IEL V-J gamma-gene rearrangements occurred for V gamma 1.2, V gamma 2, and V gamma 5 but not for V gamma 3 or V gamma 4. Sequence analyses of cloned V-J polymerase chain reaction-amplified products indicated that in both thymus-bearing mice and athymic chimeras, rearrangement of V gamma 1.2 and V gamma 5 resulted in in-frame as well as out-of-frame genes, whereas nearly all V gamma 2 rearrangements were out of frame from either type of animal. V-segment nucleotide removal occurred in most V gamma 1.2, V gamma 2, and V gamma 5 rearrangements; J-segment nucleotide removal was common in V gamma 1.2 but not in V gamma 2 or V gamma 5 rearrangements. N-segment nucleotide insertions were present in V gamma 1.2, V gamma 2, and V gamma 5 IEL rearrangements in both thymus-bearing mice and athymic chimeras, resulting in a predominant in-frame sequence for V gamma 5 and a predominant out-of-frame sequence for V gamma 2 genes. These findings demonstrate that (i) TCR gamma-gene rearrangement occurs extrathymically in IEL, (ii) rearrangements of TCR gamma genes involve the same V gene regardless of thymus influence; and (iii) the thymus does not determine the degree to which functional or nonfunctional rearrangements occur in IEL.

  16. Human-Mouse Chimeras with Normal Expression and Function Reveal That Major Domain Swapping Is Tolerated by P-Glycoprotein (ABCB1).

    Science.gov (United States)

    Pluchino, Kristen M; Hall, Matthew D; Moen, Janna K; Chufan, Eduardo E; Fetsch, Patricia A; Shukla, Suneet; Gill, Deborah R; Hyde, Stephen C; Xia, Di; Ambudkar, Suresh V; Gottesman, Michael M

    2016-02-23

    The efflux transporter P-glycoprotein (P-gp) plays a vital role in the transport of molecules across cell membranes and has been shown to interact with a panoply of functionally and structurally unrelated compounds. How human P-gp interacts with this large number of drugs has not been well understood, although structural flexibility has been implicated. To gain insight into this transporter's broad substrate specificity and to assess its ability to accommodate a variety of molecular and structural changes, we generated human-mouse P-gp chimeras by the exchange of homologous transmembrane and nucleotide-binding domains. High-level expression of these chimeras by BacMam- and baculovirus-mediated transduction in mammalian (HeLa) and insect cells, respectively, was achieved. There were no detectable differences between wild-type and chimeric P-gp in terms of cell surface expression, ability to efflux the P-gp substrates rhodamine 123, calcein-AM, and JC-1, or to be inhibited by the substrate cyclosporine A and the inhibitors tariquidar and elacridar. Additionally, expression of chimeric P-gp was able to confer a paclitaxel-resistant phenotype to HeLa cells characteristic of P-gp-mediated drug resistance. P-gp ATPase assays and photo-cross-linking with [(125)I]iodoarylazidoprazosin confirmed that transport and biochemical properties of P-gp chimeras were similar to those of wild-type P-gp, although differences in drug binding were detected when human and mouse transmembrane domains were combined. Overall, chimeras with one or two mouse P-gp domains were deemed functionally equivalent to human wild-type P-gp, demonstrating the ability of human P-gp to tolerate major structural changes.

  17. Interspecies avian brain chimeras reveal that large brain size differences are influenced by cell-interdependent processes.

    Science.gov (United States)

    Chen, Chun-Chun; Balaban, Evan; Jarvis, Erich D

    2012-01-01

    Like humans, birds that exhibit vocal learning have relatively delayed telencephalon maturation, resulting in a disproportionately smaller brain prenatally but enlarged telencephalon in adulthood relative to vocal non-learning birds. To determine if this size difference results from evolutionary changes in cell-autonomous or cell-interdependent developmental processes, we transplanted telencephala from zebra finch donors (a vocal-learning species) into Japanese quail hosts (a vocal non-learning species) during the early neural tube stage (day 2 of incubation), and harvested the chimeras at later embryonic stages (between 9-12 days of incubation). The donor and host tissues fused well with each other, with known major fiber pathways connecting the zebra finch and quail parts of the brain. However, the overall sizes of chimeric finch telencephala were larger than non-transplanted finch telencephala at the same developmental stages, even though the proportional sizes of telencephalic subregions and fiber tracts were similar to normal finches. There were no significant changes in the size of chimeric quail host midbrains, even though they were innervated by the physically smaller zebra finch brain, including the smaller retinae of the finch eyes. Chimeric zebra finch telencephala had a decreased cell density relative to normal finches. However, cell nucleus size differences between each species were maintained as in normal birds. These results suggest that telencephalic size development is partially cell-interdependent, and that the mechanisms controlling the size of different brain regions may be functionally independent.

  18. Particle gamma correlations in {sup 12}C measured with the CsI(Tl) based detector array CHIMERA

    Energy Technology Data Exchange (ETDEWEB)

    Cardella, G., E-mail: cardella@ct.infn.it [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Acosta, L. [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Amorini, F. [INFN - Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Auditore, L. [INFN Gruppo collegato di Messina and Dip. di Fisica e Scienze della Terra, Università di Messina (Italy); Berceanu, I. [Institute for Physics and Nuclear Engineering, Bucharest (Romania); Castoldi, A. [INFN Sezione di Milano e Politecnico Milano (Italy); De Filippo, E. [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Dell' Aquila, D. [Dipartimento di scienze Fisiche, Università Federico II and INFN Sezione di Napoli (Italy); Francalanza, L. [INFN - Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dip. di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); Gnoffo, B. [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Guazzoni, C. [INFN Sezione di Milano e Politecnico Milano (Italy); Lanzalone, G. [INFN - Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Facoltà di Ingegneria e Architettura, Università Kore, Enna (Italy); Lombardo, I. [Dipartimento di scienze Fisiche, Università Federico II and INFN Sezione di Napoli (Italy); Minniti, T.; Morgana, E.; Norella, S. [INFN Gruppo collegato di Messina and Dip. di Fisica e Scienze della Terra, Università di Messina (Italy); Pagano, A. [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Pagano, E.V. [INFN - Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dip. di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); Papa, M.; Pirrone, S. [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); and others

    2015-11-01

    The gamma decay of the first excited 4.44 MeV 2+level of {sup 12}C, populated by inelastic scattering of proton and {sup 16}O beams at various energies was studied in order to test γ-ray detection efficiency and the quality of angular distribution information given by the CsI(Tl) detectors of the 4π CHIMERA array. The γ-decay was measured in coincidence with ejectile scattered particles in an approximately 4π geometry allowing to extract the angular distribution in the reference frame of recoiling {sup 12}C target. The typical sin{sup 2} (2θ) behavior of angular distribution was observed in the case of {sup 16}O beam. Besides that, for the proton beam, in order to explain the observed distribution, the addition of an incoherent flat contribution was required. This latter is the effect of proton spin flip events allowing the population of M=±1 magnetic substates, that is not possible in reactions induced by {sup 16}O beam. A comparison with previously collected data, obtained measuring only in and out of plane proton-γ-ray coincidences, confirms the good quality of the angular distribution information given by the apparatus. Possible applications with radioactive beams are outlined.

  19. Designer Nodal/BMP2 Chimeras Mimic Nodal Signaling, Promote Chondrogenesis, and Reveal a BMP2-like Structure

    Science.gov (United States)

    Esquivies, Luis; Blackler, Alissa; Peran, Macarena; Rodriguez-Esteban, Concepcion; Izpisua Belmonte, Juan Carlos; Booker, Evan; Gray, Peter C.; Ahn, Chihoon; Kwiatkowski, Witek; Choe, Senyon

    2014-01-01

    Nodal, a member of the TGF-β superfamily, plays an important role in vertebrate and invertebrate early development. The biochemical study of Nodal and its signaling pathway has been a challenge, mainly because of difficulties in producing the protein in sufficient quantities. We have developed a library of stable, chemically refoldable Nodal/BMP2 chimeric ligands (NB2 library). Three chimeras, named NB250, NB260, and NB264, show Nodal-like signaling properties including dependence on the co-receptor Cripto and activation of the Smad2 pathway. NB250, like Nodal, alters heart looping during the establishment of embryonic left-right asymmetry, and both NB250 and NB260, as well as Nodal, induce chondrogenic differentiation of human adipose-derived stem cells. This Nodal-induced differentiation is shown to be more efficient than BPM2-induced differentiation. Interestingly, the crystal structure of NB250 shows a backbone scaffold similar to that of BMP2. Our results show that these chimeric ligands may have therapeutic implications in cartilage injuries. PMID:24311780

  20. Interspecies avian brain chimeras reveal that large brain size differences are influenced by cell-interdependent processes.

    Directory of Open Access Journals (Sweden)

    Chun-Chun Chen

    Full Text Available Like humans, birds that exhibit vocal learning have relatively delayed telencephalon maturation, resulting in a disproportionately smaller brain prenatally but enlarged telencephalon in adulthood relative to vocal non-learning birds. To determine if this size difference results from evolutionary changes in cell-autonomous or cell-interdependent developmental processes, we transplanted telencephala from zebra finch donors (a vocal-learning species into Japanese quail hosts (a vocal non-learning species during the early neural tube stage (day 2 of incubation, and harvested the chimeras at later embryonic stages (between 9-12 days of incubation. The donor and host tissues fused well with each other, with known major fiber pathways connecting the zebra finch and quail parts of the brain. However, the overall sizes of chimeric finch telencephala were larger than non-transplanted finch telencephala at the same developmental stages, even though the proportional sizes of telencephalic subregions and fiber tracts were similar to normal finches. There were no significant changes in the size of chimeric quail host midbrains, even though they were innervated by the physically smaller zebra finch brain, including the smaller retinae of the finch eyes. Chimeric zebra finch telencephala had a decreased cell density relative to normal finches. However, cell nucleus size differences between each species were maintained as in normal birds. These results suggest that telencephalic size development is partially cell-interdependent, and that the mechanisms controlling the size of different brain regions may be functionally independent.

  1. Detection of Hepatitis C core antibody by dual-affinity yeast chimera and smartphone-based electrochemical sensing.

    Science.gov (United States)

    Aronoff-Spencer, Eliah; Venkatesh, A G; Sun, Alex; Brickner, Howard; Looney, David; Hall, Drew A

    2016-12-15

    Yeast cell lines were genetically engineered to display Hepatitis C virus (HCV) core antigen linked to gold binding peptide (GBP) as a dual-affinity biobrick chimera. These multifunctional yeast cells adhere to the gold sensor surface while simultaneously acting as a "renewable" capture reagent for anti-HCV core antibody. This streamlined functionalization and detection strategy removes the need for traditional purification and immobilization techniques. With this biobrick construct, both optical and electrochemical immunoassays were developed. The optical immunoassays demonstrated detection of anti-HCV core antibody down to 12.3pM concentrations while the electrochemical assay demonstrated higher binding constants and dynamic range. The electrochemical format and a custom, low-cost smartphone-based potentiostat ($20 USD) yielded comparable results to assays performed on a state-of-the-art electrochemical workstation. We propose this combination of synthetic biology and scalable, point-of-care sensing has potential to provide low-cost, cutting edge diagnostic capability for many pathogens in a variety of settings.

  2. Tracking Neospora caninum parasites using chimera monoclonal antibodies against its surface antigen-related sequences (rNcSRS2).

    Science.gov (United States)

    Dong, Jinhua; Otsuki, Takahiro; Kato, Tatsuya; Park, Enoch Y

    2014-03-01

    Neosporosis, an infectious disease of cattle and dogs, causes an abortion in cattle, which has a major damage on the dairy industry worldwide. Tracking of Neospora caninum parasite that is responsible for neosporosis is required for the prevention of this infectious disease. We developed three chimera monoclonal antibodies consist of variable regions of murine antibody and constant regions of human antibody against N. caninum. Recombinant surface antigen-related sequence 2 (rNcSRS2) of N. caninum was expressed in silkworm larvae, and immunized in mice to obtain phage displaying antibody library. Through three rounds of selection, three antibodies, A6, E1 and H3, were isolated and bound to rNcSRS2 with nanomolar to micromolar affinity. In immunofluorescent staining assays, A6 and E1 bound to N. caninum strain Nc-Liv, demonstrating a successful tracking of the parasite. H3 clone bound to rNcSRS2 but not to a truncated protein without glycosylphosphatidylinositol (GPI) anchor domain in the carboxyl terminal. Amino acid sequences of A6 and E1 were similar, but that of H3 differed in the CDR-H1 region, which might be the reason of their difference of affinity. These antibodies are thought to be useful for prevention of cattle from neosporosis.

  3. Chimeras Reveal a Single Lipid-Interface Residue that Controls MscL Channel Kinetics as well as Mechanosensitivity

    Directory of Open Access Journals (Sweden)

    Li-Min Yang

    2013-02-01

    Full Text Available MscL, the highly conserved bacterial mechanosensitive channel of large conductance, serves as an osmotic “emergency release valve,” is among the best-studied mechanosensors, and is a paradigm of how a channel senses and responds to membrane tension. Although all homologs tested thus far encode channel activity, many show functional differences. We tested Escherichia coli and Staphylococcus aureus chimeras and found that the periplasmic region of the protein, particularly E. coli I49 and the equivalent S. aureus F47 at the periplasmic lipid-aqueous interface of the first transmembrane domain, drastically influences both the open dwell time and the threshold of channel opening. One mutant shows a severe hysteresis, confirming the importance of this residue in determining the energy barriers for channel gating. We propose that this site acts similarly to a spring for a clasp knife, adjusting the resistance for obtaining and stabilizing an open or closed channel structure.

  4. Design, synthesis and DNA interactions of a chimera between a platinum complex and an IHF mimicking peptide.

    Science.gov (United States)

    Rao, Harita; Damian, Mariana S; Alshiekh, Alak; Elmroth, Sofi K C; Diederichsen, Ulf

    2015-12-28

    Conjugation of metal complexes with peptide scaffolds possessing high DNA binding affinity has shown to modulate their biological activities and to enhance their interaction with DNA. In this work, a platinum complex/peptide chimera was synthesized based on a model of the Integration Host Factor (IHF), an architectural protein possessing sequence specific DNA binding and bending abilities through its interaction with a minor groove. The model peptide consists of a cyclic unit resembling the minor grove binding subdomain of IHF, a positively charged lysine dendrimer for electrostatic interactions with the DNA phosphate backbone and a flexible glycine linker tethering the two units. A norvaline derived artificial amino acid was designed to contain a dimethylethylenediamine as a bidentate platinum chelating unit, and introduced into the IHF mimicking peptides. The interaction of the chimeric peptides with various DNA sequences was studied by utilizing the following experiments: thermal melting studies, agarose gel electrophoresis for plasmid DNA unwinding experiments, and native and denaturing gel electrophoresis to visualize non-covalent and covalent peptide-DNA adducts, respectively. By incorporation of the platinum metal center within the model peptide mimicking IHF we have attempted to improve its specificity and DNA targeting ability, particularly towards those sequences containing adjacent guanine residues.

  5. Construction, Expression, and Characterization of a Recombinant Annexin B1-Low Molecular Weight Urokinase Chimera in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Hong-Li YAN; Wei-Ting WANG; Yan HE; Zhuan-You ZHAO; Yuan-Jian GAO; Yi ZHANG; Shu-Han SUN

    2004-01-01

    To produce a thrombi-targeting plasminogen activator,low molecular weight single-chain urokinase gene(scuPA32k)was spliced with the full-length cDNA of annexin B 1 gene(anxB1)by overlap extension method.The fused gene anxBlscuPA was ligated into pET28a vector,transformed into E.coli BL21-RIL,and then induced to express under the control of T7 promoter.The AnxB 1ScuPA protein expressed amounted to 22% of the total bacterial proteins.The product was refolded,and then purified by using DEAE Sepharose fast flow ion-exchange column and Superdex S-200 gel-filtration column.HPLC analysis revealed that the final purity is about 95%.The specific activity ofAnxB 1ScuPA,measured as amidolytic activity,reached 100,000 IU/mg.It had a similar S2444 catalytic efficiency(kcat/Km)to ScuPA32k,and also showed high activated-platelet membrane-binding activity and anticoagulant activity,indicating that the chimera fully retained the components of enzymatic and membrane-binding activities of the parent molecules.In vivo test revealed that,the dogs administered with AnxB 1ScuPA had less reperfusion time,higher reperfusion ratio,and less bleeding effects than those with urokinase.These findings indicated that AnxB 1ScuPAmight have advantages over current available thrombolytic agents.

  6. Chimera-free, high copy number YAC libraries and efficient methods of analysis. Final technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-10-01

    The first experiment involved a low chimera YAC library in recombination deficient host strains. To determine if the genetic background of the yeast host strain contributes to the formation of chimeric YACs the same YAC ligation mixture was introduced into three isogenic yeast hosts differing only in their recombination abilities. To prepare YACs, human genomic DNA was partially digested with EcoR1 and then ligated to YAC vector pCGS966 arms. DNA was size fractionated before and after ligation by preparative pulsed field gel electrophoresis (CHEF), selecting for fragments greater than 400 kb, and introduced into competent spheroplasts. CHEF gel Southern blots of resulting colony-purified YACs were probed with human DNA to determine if multiple YACs or YAC fragments were present in the same cell. The frequency of chimeric YACs was measured by fluorescence in situ hybridization (FISH) of YACs to human prometaphase spreads. YACs that hybridized to more than one location were assumed to be chimeric. In the second experiment new YAC vectors featuring tags for capture of YACs and YAC inserts were constructed. Yeast Artificial Chromosomes (YACs) have been of tremendous value in the physical mapping of the human genome. Because they can carry very large inserts, YACs are likely not only to contain entire genes but also their control elements. However, the only mode of purification of YAC DNA from current commonly used YAC libraries such as the CEPH library is by pulsed field gel electrophoresis. This is an inefficient, time consuming process and due to the single copy nature of these YACs, often result in poor yields. The vector pCGS1000 was designed to test new efficient ways of YAC DNA purification.

  7. [Leaf anatomy of the mosaic ficus benjamina cv. Starlight and interaction of source and sink chimera components].

    Science.gov (United States)

    Labunskaia, E A; Zhigalova, T V; Chub, V V

    2007-01-01

    Leaf anatomy was studied in the mosaic Ficus benjamina cv. Starlight and non-chimeric Ficus benjamina cv. Daniel. The number of chloroplasts in a white, chlorophyll-deficient tissue declines as compared to the green tissue. However, their functional activity is retained. The leaf of the mosaic F. benjamina contains two or, sometimes, three subepidermal layers. Mesophyll forms one layer in the green and white parts of leaf palisade and one white and one green layer in the transitional zone (edge). In the transitional zone, green spongy mesophyll is located between two white spongy layers and the proportion of photosynthesizing cells varies. In cv. Daniel, there are two subepidermal layers and one layer of columnar mesophyll cells. According to the morphometry data, the proportion of white zone in the leaf correlates with the leaf position in the whole shoot: the higher the branch order, the larger the proportion of white zone. The total leaf area depends also on its position in the shoot. No such correlation was found in non-chimeric F. benjamina cv. Daniel. In the mosaic chimera, the source-sink status appears to depend on the leaf position in the shoot. Experiments with individual shoots of the same order and elimination of all lateral shoots have shown that the proportion of white zone in new leaves on the shoot increases with the total area of green zone. Thus, the area of assimilating shoot surface affects the formation of leaves in the meristem. A hypothesis was put forward that the source-sink state affects the ratio of green and white parts in the leaf primordium. Products of photosynthesis (carbohydrates) are a possible metabolic signal affecting the meristem. It cannot be excluded as well that the hormonal state undergoes changes in the chimeric plant.

  8. CHIMERA: Top-down model for hierarchical, overlapping and directed cluster structures in directed and weighted complex networks

    Science.gov (United States)

    Franke, R.

    2016-11-01

    In many networks discovered in biology, medicine, neuroscience and other disciplines special properties like a certain degree distribution and hierarchical cluster structure (also called communities) can be observed as general organizing principles. Detecting the cluster structure of an unknown network promises to identify functional subdivisions, hierarchy and interactions on a mesoscale. It is not trivial choosing an appropriate detection algorithm because there are multiple network, cluster and algorithmic properties to be considered. Edges can be weighted and/or directed, clusters overlap or build a hierarchy in several ways. Algorithms differ not only in runtime, memory requirements but also in allowed network and cluster properties. They are based on a specific definition of what a cluster is, too. On the one hand, a comprehensive network creation model is needed to build a large variety of benchmark networks with different reasonable structures to compare algorithms. On the other hand, if a cluster structure is already known, it is desirable to separate effects of this structure from other network properties. This can be done with null model networks that mimic an observed cluster structure to improve statistics on other network features. A third important application is the general study of properties in networks with different cluster structures, possibly evolving over time. Currently there are good benchmark and creation models available. But what is left is a precise sandbox model to build hierarchical, overlapping and directed clusters for undirected or directed, binary or weighted complex random networks on basis of a sophisticated blueprint. This gap shall be closed by the model CHIMERA (Cluster Hierarchy Interconnection Model for Evaluation, Research and Analysis) which will be introduced and described here for the first time.

  9. Soluble Jagged 1/Fc chimera protein induces the differentiation and maturation of bone marrow-derived dendritic cells

    Institute of Scientific and Technical Information of China (English)

    XING FeiYue; LIU Jing; YU Zhe; JI YuHua

    2008-01-01

    A soluble Jagged 1/Fc chimera protein (Jagged 1/Fc) was directly used to induce differentiation and maturation of bone marrow-derived dendritic cells (DCs) in mice in vitro. A model of inducing and am-plifying DCs in vitro was established. The effect of Jagged 1/Fc on morphology of DCs induced by both rmGM-CSF and rmlL-4 was observed under a confocal microscope. A fluorescein-labeled monoclonal antibody staining combined with flow cytometry was applied to detect the effect of Jagged 1/Fc on the expression of CD11c, MHC-Ⅱ, CD86, CD80 and CD40 molecules on the surface of DCs. The results showed that Jagged 1/Fc did not affect the morphological properties of DC differentiation induced by both rmGM-CSF and rmlL-4. But it could promote the differentiation and maturation of DCs induced by both. The effect of it was strikingly different in the expression profile of co-stimulating molecules and the morphologic properties of DCs from lipopolysaccharide (LPS). The levels of MHC-Ⅱ and CD40 molecule expression on the surface of DCs stimulated by Jagged 1/Fc were significantly lower than those stimulated by LPS, and the level of CD80 expression on the surface of DCs induced by Jagged 1/Fc was near to that induced by LPS. Jagged 1/Fc had no influence on the expression of CD86 mole-cule on the surface of DCs. Jagged 1/Fc when used alone could not maintain the growth, differentiation and maturation of DCs. All the findings indicate that Jagged 1/Fc influences the differentiation and maturation of DCs, which is not markedly similar to LPS, providing important evidence for its devel-opment and application as a novel immunosuppressant.

  10. Bioassays for TSH receptor autoantibodies, from FRTL-5 cells to TSH receptor–LH/CG receptor chimeras: the contribution of Leonard D. Kohn

    Directory of Open Access Journals (Sweden)

    Cesidio Giuliani

    2016-07-01

    Full Text Available Since the discovery 60 years ago of the long-acting thyroid stimulator by Adams and Purves, great progress has been made in the detection of thyroid-stimulating hormone (TSH receptor autoantibodies (TRAbs in Graves’ disease. Today, commercial assays are available that can detect TRAbs with high accuracy and provide diagnostic and prognostic evaluation of patients with Graves’ disease. The present review focuses on the development of TRAbs bioassays, and particularly on the role that Leonard D. Kohn had in this. Indeed, 30 years ago, the Kohn group developed a bioassay based on the use of FRTL-5 cells that was characterized by high reproducibility, feasibility, and diagnostic accuracy. Using this FRTL-5 bioassay, Kohn and his colleagues were the first to develop monoclonal antibodies against the TSH receptor. Furthermore, they demonstrated the multifaceted functional nature of TRAbs in patients with Graves’ disease, with the identification of stimulating and blocking TRAbs, and even antibodies that activated pathways other than cAMP. After the cloning of the TSH receptor, the Kohn laboratory constructed human TSH receptor–rat luteinizing hormone/ chorionic gonadotropin receptor chimeras. This paved the way to a new bioassay based on the use of nonthyroid cells transfected with the Mc4 chimera. The new Mc4 bioassay is characterized by high diagnostic and prognostic accuracy, greater than for other assays. The availability of a commercial kit based on the Mc4 chimera is spreading the use of this assay worldwide, indicating its benefits for these patients with Graves’ disease. This review also describes the main contributions made by others researchers in TSH receptor molecular biology and TRAbs assay, especially with the development of highly potent monoclonal antibodies. A comparison of the diagnostic accuracies of the main TRAbs assays, as both immunoassays and bioassays, is also provided.

  11. Bioassays for TSH Receptor Autoantibodies, from FRTL-5 Cells to TSH Receptor–LH/CG Receptor Chimeras: The Contribution of Leonard D. Kohn

    Science.gov (United States)

    Giuliani, Cesidio; Saji, Motoyasu; Bucci, Ines; Napolitano, Giorgio

    2016-01-01

    Since the discovery 60 years ago of the “long-acting thyroid stimulator” by Adams and Purves, great progress has been made in the detection of thyroid-stimulating hormone (TSH) receptor (TSHR) autoantibodies (TRAbs) in Graves’ disease. Today, commercial assays are available that can detect TRAbs with high accuracy and provide diagnostic and prognostic evaluation of patients with Graves’ disease. The present review focuses on the development of TRAbs bioassays, and particularly on the role that Leonard D. Kohn had in this. Indeed, 30 years ago, the Kohn group developed a bioassay based on the use of FRTL-5 cells that was characterized by high reproducibility, feasibility, and diagnostic accuracy. Using this FRTL-5 bioassay, Kohn and his colleagues were the first to develop monoclonal antibodies (moAbs) against the TSHR. Furthermore, they demonstrated the multifaceted functional nature of TRAbs in patients with Graves’ disease, with the identification of stimulating and blocking TRAbs, and even antibodies that activated pathways other than cAMP. After the cloning of the TSHR, the Kohn laboratory constructed human TSHR–rat luteinizing hormone/chorionic gonadotropin receptor chimeras. This paved the way to a new bioassay based on the use of non-thyroid cells transfected with the Mc4 chimera. The new Mc4 bioassay is characterized by high diagnostic and prognostic accuracy, greater than for other assays. The availability of a commercial kit based on the Mc4 chimera is spreading the use of this assay worldwide, indicating its benefits for these patients with Graves’ disease. This review also describes the main contributions made by other researchers in TSHR molecular biology and TRAbs assay, especially with the development of highly potent moAbs. A comparison of the diagnostic accuracies of the main TRAbs assays, as both immunoassays and bioassays, is also provided. PMID:27504107

  12. Bioassays for TSH Receptor Autoantibodies, from FRTL-5 Cells to TSH Receptor-LH/CG Receptor Chimeras: The Contribution of Leonard D. Kohn.

    Science.gov (United States)

    Giuliani, Cesidio; Saji, Motoyasu; Bucci, Ines; Napolitano, Giorgio

    2016-01-01

    Since the discovery 60 years ago of the "long-acting thyroid stimulator" by Adams and Purves, great progress has been made in the detection of thyroid-stimulating hormone (TSH) receptor (TSHR) autoantibodies (TRAbs) in Graves' disease. Today, commercial assays are available that can detect TRAbs with high accuracy and provide diagnostic and prognostic evaluation of patients with Graves' disease. The present review focuses on the development of TRAbs bioassays, and particularly on the role that Leonard D. Kohn had in this. Indeed, 30 years ago, the Kohn group developed a bioassay based on the use of FRTL-5 cells that was characterized by high reproducibility, feasibility, and diagnostic accuracy. Using this FRTL-5 bioassay, Kohn and his colleagues were the first to develop monoclonal antibodies (moAbs) against the TSHR. Furthermore, they demonstrated the multifaceted functional nature of TRAbs in patients with Graves' disease, with the identification of stimulating and blocking TRAbs, and even antibodies that activated pathways other than cAMP. After the cloning of the TSHR, the Kohn laboratory constructed human TSHR-rat luteinizing hormone/chorionic gonadotropin receptor chimeras. This paved the way to a new bioassay based on the use of non-thyroid cells transfected with the Mc4 chimera. The new Mc4 bioassay is characterized by high diagnostic and prognostic accuracy, greater than for other assays. The availability of a commercial kit based on the Mc4 chimera is spreading the use of this assay worldwide, indicating its benefits for these patients with Graves' disease. This review also describes the main contributions made by other researchers in TSHR molecular biology and TRAbs assay, especially with the development of highly potent moAbs. A comparison of the diagnostic accuracies of the main TRAbs assays, as both immunoassays and bioassays, is also provided.

  13. Transient replication of a hepatitis C virus genotype 1b replicon chimera encoding NS5A-5B from genotype 3a.

    Science.gov (United States)

    Kylefjord, Helen; Danielsson, Axel; Sedig, Susanne; Belda, Oscar; Wiktelius, Daniel; Vrang, Lotta; Targett-Adams, Paul

    2014-01-01

    Although hepatitis C virus (HCV) is a pathogen of global significance, experimental therapies in current clinical development include highly efficacious all-oral combinations of HCV direct-acting antivirals (DAAs). If approved for use, these new treatment regimens will impact dramatically upon our capacity to eradicate HCV in the majority of virus-infected patients. However, recent data from late-stage clinical evaluations demonstrated that individuals infected with HCV genotype (GT) 3 responded less well to all-oral DAA combinations than patients infected with other HCV GTs. In light of these observations, the present study sought to expand the number of molecular tools available to investigate small molecule-mediated inhibition of HCV GT3 NS5A and NS5B proteins in preclinical tissue-culture systems. Accordingly, a novel subgenomic HCV replicon chimera was created by utilizing a GT1b backbone modified to produce NS5A and NS5B proteins from a consensus sequence generated from HCV GT3a genomic sequences deposited online at the European Hepatitis C Virus database. This approach avoided the need to isolate and amplify HCV genomes from sera derived from HCV-infected patients. The replicon chimera, together with a version engineered to express NS5A encoding a Y93H mutation, demonstrated levels of replication in transient assays robust enough to assess accurate antiviral activities of inhibitors representing different HCV DAA classes. Thus, the replicon chimera represents a new simple molecular tool suitable for drug discovery programmes aimed at investigating, understanding, and improving GT3a activities of HCV DAAs targeting NS5A or NS5B.

  14. Screening of biotechnical parameters for production of bovine inter-subspecies embryonic chimeras by the aggregation of tetraploid Bos indicus and diploid crossbred Bos taurus embryos.

    Science.gov (United States)

    Razza, Eduardo M; Satrapa, Rafael A; Emanuelli, Isabele P; Barros, Ciro M; Nogueira, Marcelo F G

    2016-03-01

    The aggregation of a tetraploid zebu embryo (Bos indicus, a thermotolerant breed) with a diploid taurine embryo (Bos taurus, a thermosensitive breed) should create a complete taurine fetus, whose extra-embryonic components, e.g., the chorion, is derived mainly from the zebu embryo. These zebu-derived extra-embryonic components may interact positively with the taurine embryo/fetus during pregnancy in a tropical environment. We tested different parameters for the production of tetraploid Nelore (Bos indicus) embryos to be combined via aggregation with crossbred Bos taurus (diploid) embryos in order to produce viable chimeric blastocysts. Bovine (Bos indicus or crossbred Bos taurus) embryos were produced in vitro according to standard procedures. Two-cell Bos indicus embryos were submitted to electrofusion with varying numbers of pulses (1 or 2), voltages (0.4, 0.5, 0.75, 1.0, 1.4 and 5.0 kV/cm) and time (20, 25, 50 and 60 μs) to produce tetraploid embryos. Electrofused embryos were cultured with crossbred non-fused embryos to form chimeras that developed until the blastocyst stage. The best fusion parameter was 0.75 kV/cm for 60 μs. Four chimeric blastocysts (tetraploid Nelore with diploid crossbred Holstein) were formed after 31 attempts in 4 replicates (13%). We established an optimal procedure for the production of tetraploid Bos indicus (4n) embryos and embryonic chimeras by aggregation of crossbred Bos taurus (2n) with Bos indicus (4n) embryos. This technique would be valid in applied research, by producing exclusively taurine calves, but with placental elements from the Bos indicus breed, following transfer of these chimeras into recipient cows.

  15. NHE1 inhibition by amiloride- and benzoylguanidine-type compounds. Inhibitor binding loci deduced from chimeras of NHE1 homologues with endogenous differences in inhibitor sensitivity

    DEFF Research Database (Denmark)

    Pedersen, Stine F; King, Scott A; Nygaard, Eva B;

    2007-01-01

    The interaction of the ubiquitous Na(+)/H(+) exchanger, NHE1, with its commonly used inhibitors, amiloride- and benzoylguanidine (Hoechst type inhibitor (HOE))-type compounds, is incompletely understood. We previously cloned NHE1 from Amphiuma tridactylum (AtNHE1) and Pleuronectes americanus (Pa......NHE1). Although highly homologous to the amiloride- and HOE-sensitive human NHE1 (hNHE1), AtNHE1 is insensitive to HOE-type and PaNHE1 to both amiloride- and HOE-type compounds. Here we generated chimeras to "knock in" amiloride and HOE sensitivity to PaNHE1, and we thereby identified several NHE1...

  16. Adaptation of Soybean mosaic virus avirulent chimeras containing P3 sequences from virulent strains to Rsv1-genotype soybeans is mediated by mutations in HC-Pro.

    Science.gov (United States)

    Hajimorad, M R; Eggenberger, A L; Hill, J H

    2008-07-01

    In Rsv1-genotype soybean, Soybean mosaic virus (SMV)-N (an avirulent isolate of strain G2) elicits extreme resistance (ER) whereas strain SMV-G7 provokes a lethal systemic hypersensitive response (LSHR). SMV-G7d, an experimentally evolved variant of SMV-G7, induces systemic mosaic. Thus, for Rsv1-genotype soybean, SMV-N is avirulent whereas SMV-G7 and SMV-G7d are both virulent. Exploiting these differential interactions, we recently mapped the elicitor functions of SMV provoking Rsv1-mediated ER and LSHR to the N-terminal 271 amino acids of P3 from SMV-N and SMV-G7, respectively. The phenotype of both SMV-G7 and SMV-G7d were rendered avirulent on Rsv1-genotype soybean when the part of the genome encoding the N-terminus or the entire P3 cistron was replaced with that from SMV-N; however, reciprocal exchanges did not confer virulence to SMV-N-derived P3 chimeras. Here, we describe virulent SMV-N-derived P3 chimeras containing the full-length or the N-terminal P3 from SMV-G7 or SMV-G7d, with or without additional mutations in P3, that were selected on Rsv1-genotype soybean by sequential transfers on rsv1 and Rsv1-genotype soybean. Sequence analyses of the P3 and helper-component proteinase (HC-Pro) cistrons of progeny recovered from Rsv1-genotype soybean consistently revealed the presence of mutations in HC-Pro. Interestingly, the precise mutations in HC-Pro required for the adaptation varied among the chimeras. No mutation was detected in the HC-Pro of progeny passaged continuously in rsv1-genotype soybean, suggesting that selection is a consequence of pressure imposed by Rsv1. Mutations in HC-Pro alone failed to confer virulence to SMV-N; however, reconstruction of mutations in HC-Pro of the SMV-N-derived P3 chimeras resulted in virulence. Taken together, the data suggest that HC-Pro complementation of P3 is essential for SMV virulence on Rsv1-genotype soybean.

  17. Avoidance and Potential Remedy Solutions of Chimeras in Reconstructing the Phylogeny of Aphids Using the 16S rRNA Gene of Buchnera: A Case in Lachninae (Hemiptera).

    Science.gov (United States)

    Chen, Rui; Wang, Zhe; Chen, Jing; Qiao, Ge-Xia

    2015-08-25

    It is known that PCR amplification of highly homologous genes from complex DNA mixtures can generate a significant proportion of chimeric sequences. The 16S rRNA gene is not only widely used in estimating the species diversity of endosymbionts in aphids but also used to explore the co-diversification of aphids and their endosymbionts. Thus, chimeric sequences may lead to the discovery of non-existent endosymbiont species and mislead Buchnera-based phylogenetic analysis that lead to false conclusions. In this study, a high probability (6.49%) of chimeric sequence occurrence was found in the amplified 16S rRNA gene sequences of endosymbionts from aphid species in the subfamily Lachninae. These chimeras are hybrid products of multiple parent sequences from the dominant species of endosymbionts in each corresponding host. It is difficult to identify the chimeric sequences of a new or unidentified species due to the high variability of their main parent, Buchnera aphidicola, and because the chimeric sequences can confuse the phylogenetic analysis of 16S rRNA gene sequences. These chimeras present a challenge to Buchnera-based phylogenetic research in aphids. Thus, our study strongly suggests that using appropriate methods to detect chimeric 16S rRNA sequences may avoid some false conclusions in endosymbiont-based aphid research.

  18. Generation of anti-idiotype scFv for pharmacokinetic measurement in lymphoma patients treated with chimera anti-CD22 antibody SM03.

    Directory of Open Access Journals (Sweden)

    Qi Zhao

    Full Text Available Pre-clinical and clinical studies of therapeutic antibodies require highly specific reagents to examine their immune responses, bio-distributions, immunogenicity, and pharmacodynamics in patients. Selective antigen-mimicking anti-idiotype antibody facilitates the assessment of therapeutic antibody in the detection, quantitation and characterization of antibody immune responses. Using mouse specific degenerate primer pairs and splenocytic RNA, we generated an idiotype antibody-immunized phage-displayed scFv library in which an anti-idiotype antibody against the therapeutic chimera anti-CD22 antibody SM03 was isolated. The anti-idiotype scFv recognized the idiotype of anti-CD22 antibody and inhibited binding of SM03 to CD22 on Raji cell surface. The anti-idiotype scFv was subsequently classified as Ab2γ type. Moreover, our results also demonstrated firstly that the anti-idiotype scFv could be used for pharmacokinetic measurement of circulating residual antibody in lymphoma patients treated with chimera anti-CD22 monoclonal antibody SM03. Of important, the present approach could be easily adopted to generate anti-idiotype antibodies for therapeutic antibodies targeting membrane proteins, saving the cost and time for producing a soluble antigen.

  19. PNA Peptide chimerae

    DEFF Research Database (Denmark)

    Koch, T.; Næsby, M.; Wittung, P.;

    1995-01-01

    Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields.......Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields....

  20. Chimeras: an ethical consideration

    Directory of Open Access Journals (Sweden)

    H.J.G. Zandman

    2011-07-01

    Full Text Available Scientists have started with experimentation that raises difficult ethical questions. It comprises taking material from the human blueprint (DNA and inserting this in various test animals. The purpose of such research is noble, namely the alleviation of hu- man suffering. Yet the ethical ramifications of blending the hu- man and animal genome are significant, especially for Chris- tians. The creation of all living entities after their kind and the image-bearing dignity attributed to man both come under se- vere ethical stress for those who presuppose divine order in God’s ecology.  For non-Christians the philosophical dilemma ought not to exist in the ethical sense if applied at the purest level. If the human is merely a kind of animal, along with and ontologically not diffe- rent from other animals, there is little logical reason to object to chimeric research apart from a concern about what such re- search and application might do to the order of life pragmati- cally. However, many non-Christian do object. Man is made in God’s image and the concept of human dignity and a universal sense of right and wrong still binds Christians and non-Chris- tians when considering ethics in the field of chimeric research. As the mixing of human stem cells with embryonic animals takes place, certain non-Christian authors protest that human dignity is being diminished and the animal essence is being vio- lated.

  1. Efficient generation of germ line transmitting chimeras from C57BL/6N ES cells by aggregation with outbred host embryos.

    Directory of Open Access Journals (Sweden)

    Marina Gertsenstein

    Full Text Available Genetically modified mouse strains derived from embryonic stem (ES cells have become essential tools for functional genomics and biomedical research. Large scale mutagenesis projects are producing libraries of mutant C57BL/6 (B6 ES cells to enable the functional annotation of every gene of the mouse genome. To realize the utility of these resources, efficient and accessible methods of generating mutant mice from these ES cells are necessary. Here, we describe a combination of ICR morula aggregation and a chemically-defined culture medium with widely available and accessible components for the high efficiency generation of germline transmitting chimeras from C57BL/6N ES cells. Together these methods will ease the access of the broader biomedical research community to the publicly available B6 ES cell resources.

  2. Optimization of three-dimensional imaging on in vitro produced porcine blastocysts and chimeras for stem cell testing: A technology report

    DEFF Research Database (Denmark)

    Secher, Jan; Freude, Karla; Li, Rong

    2015-01-01

    Differential staining is an immunocytochemical staining that visualizes trophectoderm (TE) and the inner cell mass (ICM) of the blastocysts. It is used to determine the blastocyst quality, but could also be a useful tool to assess the integration site of injected cells into the early embryo....... This is relevant for testing of presumed pluripotent stem cells. The gold standard for pluripotent stem cells is to test if the cells are capable of contributing to germline chimeras. Differential staining can be used to evaluate the possibility of chimeric contribution; if the cells are located in the area...... of the ICM they are likely to contribute to the fetus and if they are located in the area of the TE they are likely to contribute to the fetal membranes. In this article, we optimize on methods for embryo staining and mounting so that the exact location of injected stem cells within preimplantation porcine...

  3. Reversal of type 1 diabetes by a new MHC II-peptide chimera: "Single-epitope-mediated suppression" to stabilize a polyclonal autoimmune T-cell process.

    Science.gov (United States)

    Lin, Marvin; Stoica-Nazarov, Cristina; Surls, Jacqueline; Kehl, Margaret; Bona, Constantin; Olsen, Cara; Brumeanu, Teodor D; Casares, Sofia

    2010-08-01

    Polyclonality of self-reactive CD4(+) T cells is the hallmark of several autoimmune diseases like type 1 diabetes. We have previously reported that a soluble dimeric MHC II-peptide chimera prevents and reverses type 1 diabetes induced by a monoclonal diabetogenic T-cell population in double Tg mice [Casares, S. et al., Nat. Immunol. 2002. 3: 383-391]. Since most of the glutamic acid decarboxylase 65 (GAD65)-specific CD4(+) T cells in the NOD mouse are tolerogenic but unable to function in an autoimmune environment, we have activated a silent, monoclonal T-regulatory cell population (GAD65(217-230)-specific CD4(+) T cells) using a soluble I-A(αβ) (g7)/GAD65(217-230)/Fcγ2a dimer, and measured the effect on the ongoing polyclonal diabetogenic T-cell process. Activated GAD65(217-230)-specific T cells and a fraction of the diabetogenic (B(9-23)-specific) T cells were polarized toward the IL-10-secreting T-regulatory type 1-like function in the pancreas of diabetic NOD mice. More importantly, this led to the reversal of hyperglycemia for more than 2 months post-therapy in 80% of mice in the context of stabilization of pancreatic insulitis and improved insulin secretion by the β cells. These findings argue for the stabilization of a polyclonal self-reactive T-cell process by a single epitope-mediated bystander suppression. Dimeric MHC class II-peptide chimeras-like approach may provide rational grounds for the development of more efficient antigen-specific therapies in type 1 diabetes.

  4. Development of a tightly regulated and highly inducible ecdysone receptor gene switch for plants through the use of retinoid X receptor chimeras.

    Science.gov (United States)

    Tavva, Venkata S; Dinkins, Randy D; Palli, Subba R; Collins, Glenn B

    2007-10-01

    Chemical inducible gene regulation systems provide essential tools for the precise regulation of transgene expression in plants and animals. Recent development of a two-hybrid ecdysone receptor (EcR) gene regulation system has solved some of the drawbacks that were associated with the monopartate gene switch. To further improve the versatility of the two-hybrid EcR gene switch for wide spread use in plants, chimeras between Homo sapiens retinoid X receptor (HsRXR) and insect, Locusta migratoria RXR (LmRXR) were tested in tobacco protoplasts as partners with Choristoneura fumiferana EcR (CfEcR) in inducing expression of the luciferase reporter gene. The RXR chimera 9 (CH9) along with CfEcR, in a two-hybrid format gave the best results in terms of low-background expression levels in the absence of ligand and high-induced expression levels of the reporter gene in the presence of nanomolar concentrations of the methoxyfenozide ligand. The performance of CH9 was further tested in corn and soybean protoplasts and the data obtained was compared with the other EcR switches that contained the wild-type LmRXR or HsRXR as EcR partners. In both transient expression studies and stable transformation experiments, the fold induction values obtained with the CH9 switch were several times higher than the values obtained with the other EcR switches containing LmRXR or HsRXR. The new CfEcR two-hybrid gene switch that uses the RXR CH9 as a partner in inducing reporter gene expression provides an efficient, ligand-sensitive and tightly regulated gene switch for plants.

  5. Transient Expression of an LEDGF/p75 Chimera Retargets Lentivector Integration and Functionally Rescues in a Model for X-CGD.

    Science.gov (United States)

    Vets, Sofie; De Rijck, Jan; Brendel, Christian; Grez, Manuel; Bushman, Frederic; Debyser, Zeger; Gijsbers, Rik

    2013-03-05

    Retrovirus-based vectors are commonly used as delivery vehicles to correct genetic diseases because of their ability to integrate new sequences stably. However, adverse events in which vector integration activates proto-oncogenes, leading to clonal expansion and leukemogenesis hamper their application. The host cell-encoded lens epithelium-derived growth factor (LEDGF/p75) binds lentiviral integrase and targets integration to active transcription units. We demonstrated earlier that replacing the LEDGF/p75 chromatin interaction domain with an alternative DNA-binding protein could retarget integration. Here, we show that transient expression of the chimeric protein using mRNA electroporation efficiently redirects lentiviral vector (LV) integration in wild-type (WT) cells. We then employed this technology in a model for X-linked chronic granulomatous disease (X-CGD) using myelomonocytic PLB-985 gp91(-/-) cells. Following electroporation with mRNA encoding the LEDGF-chimera, the cells were treated with a therapeutic lentivector encoding gp91(phox). Integration site analysis revealed retargeted integration away from genes and towards heterochromatin-binding protein 1β (CBX1)-binding sites, in regions enriched in marks associated with gene silencing. Nevertheless, gp91(phox) expression was stable for at least 6 months after electroporation and NADPH-oxidase activity was restored to normal levels as determined by superoxide production. Together, these data provide proof-of-principle that transient expression of engineered LEDGF-chimera can retarget lentivector integration and rescues the disease phenotype in a cell model, opening perspectives for safer gene therapy.Molecular Therapy - Nucleic Acids (2013) 2, e77; doi:10.1038/mtna.2013.4; published online 5 March 2013.

  6. Solid-State Nuclear Magnetic Resonance Investigation of the Structural Topology and Lipid Interactions of a Viral Fusion Protein Chimera Containing the Fusion Peptide and Transmembrane Domain.

    Science.gov (United States)

    Yao, Hongwei; Lee, Myungwoon; Liao, Shu-Yu; Hong, Mei

    2016-12-13

    The fusion peptide (FP) and transmembrane domain (TMD) of viral fusion proteins play important roles during virus-cell membrane fusion, by inducing membrane curvature and transient dehydration. The structure of the water-soluble ectodomain of viral fusion proteins has been extensively studied crystallographically, but the structures of the FP and TMD bound to phospholipid membranes are not well understood. We recently investigated the conformations and lipid interactions of the separate FP and TMD peptides of parainfluenza virus 5 (PIV5) fusion protein F using solid-state nuclear magnetic resonance. These studies provide structural information about the two domains when they are spatially well separated in the fusion process. To investigate how these two domains are structured relative to each other in the postfusion state, when the ectodomain forms a six-helix bundle that is thought to force the FP and TMD together in the membrane, we have now expressed and purified a chimera of the FP and TMD, connected by a Gly-Lys linker, and measured the chemical shifts and interdomain contacts of the protein in several lipid membranes. The FP-TMD chimera exhibits α-helical chemical shifts in all the membranes examined and does not cause strong curvature of lamellar membranes or membranes with negative spontaneous curvature. These properties differ qualitatively from those of the separate peptides, indicating that the FP and TMD interact with each other in the lipid membrane. However, no (13)C-(13)C cross peaks are observed in two-dimensional correlation spectra, suggesting that the two helices are not tightly associated. These results suggest that the ectodomain six-helix bundle does not propagate into the membrane to the two hydrophobic termini. However, the loosely associated FP and TMD helices are found to generate significant negative Gaussian curvature to membranes that possess spontaneous positive curvature, consistent with the notion that the FP-TMD assembly may

  7. Tamoxifen-regulated adenoviral E1A chimeras for the control of tumor selective oncolytic adenovirus replication in vitro and in vivo.

    Science.gov (United States)

    Sipo, I; Wang, X; Hurtado Picó, A; Suckau, L; Weger, S; Poller, W; Fechner, H

    2006-01-01

    Pharmacological control is a desirable safety feature of oncolytic adenoviruses (oAdV). It has recently been shown that oAdV replication may be controlled by drug-dependent transcriptional regulation of E1A expression. Here, we present a novel concept that relies on tamoxifen-dependent regulation of E1A activity through functional linkage to the mutated hormone-binding domain of the murine estrogen receptor (Mer). Four different E1A-Mer chimeras (ME, EM, E(DeltaNLS)M, MEM) were constructed and inserted into the adenoviral genome under control of a lung-specific surfactant protein B promoter. The highest degree of regulation in vitro was seen for the corresponding oAdVs Ad.E(DeltaNLS)M and Ad.MEM, which exhibited an up to 100-fold higher oAdV replication in the presence as compared with the absence of 4-OH-tamoxifen. Moreover, destruction of nontarget cells was six- and 13-fold reduced for Ad.E(DeltaNLS)M and Ad.MEM, respectively, as compared with Ad.E. Further investigations supported tamoxifen-dependent regulation of Ad.E(DeltaNLS)M and Ad.MEM in vivo. Induction of Ad.E(DeltaNLS)M inhibited growth of H441 lung tumors as efficient as a control oAdV expressing E1A. E(DeltaNLS)M and the MEM chimeras can be easily inserted into a single vector genome, which extends their application to existing oAdVs and strongly facilitates in vivo application.

  8. Primordial germ cell-mediated chimera technology produces viable pure-line Houbara bustard offspring: potential for repopulating an endangered species.

    Directory of Open Access Journals (Sweden)

    Ulrich Wernery

    Full Text Available BACKGROUND: The Houbara bustard (Chlamydotis undulata is a wild seasonal breeding bird populating arid sandy semi-desert habitats in North Africa and the Middle East. Its population has declined drastically during the last two decades and it is classified as vulnerable. Captive breeding programmes have, hitherto, been unsuccessful in reviving population numbers and thus radical technological solutions are essential for the long term survival of this species. The purpose of this study was to investigate the use of primordial germ cell-mediated chimera technology to produce viable Houbara bustard offspring. METHODOLOGY/PRINCIPAL FINDINGS: Embryonic gonadal tissue was dissected from Houbara bustard embryos at eight days post-incubation. Subsequently, Houbara tissue containing gonadal primordial germ cells (gPGCs was injected into White Leghorn chicken (Gallus gallus domesticus embryos, producing 83/138 surviving male chimeric embryos, of which 35 chimeric roosters reached sexual maturity after 5 months. The incorporation and differentiation of Houbara gPGCs in chimeric chicken testis were assessed by PCR with Houbara-specific primers and 31.3% (5/16 gonads collected from the injected chicken embryos showed the presence of donor Houbara cells. A total of 302 semen samples from 34 chimeric roosters were analyzed and eight were confirmed as germline chimeras. Semen samples from these eight roosters were used to artificially inseminate three female Houbara bustards. Subsequently, 45 Houbara eggs were obtained and incubated, two of which were fertile. One egg hatched as a male live born Houbara; the other was female but died before hatching. Genotyping confirmed that the male chick was a pure-line Houbara derived from a chimeric rooster. CONCLUSION: This study demonstrates for the first time that Houbara gPGCs can migrate, differentiate and eventually give rise to functional sperm in the chimeric chicken testis. This approach may provide a promising

  9. Tolerance of CD8+ T cells developing in parent-->F1 chimeras prepared with supralethal irradiation: step-wise induction of tolerance in the intrathymic and extrathymic environments.

    Science.gov (United States)

    Kosaka, H; Sprent, J

    1993-02-01

    Tolerance of CD8+ cells was examined in parent-->F1 bone marrow chimeras (BMC) prepared with supralethal irradiation; host class I expression in the chimeras was limited to non-BM-derived cells. In terms of helper-independent proliferative responses in vitro and induction of graft-vs.-host disease on adoptive transfer, CD8+ cells from long-term chimeras showed profound tolerance to host antigens irrespective of whether the cells were prepared from the thymus or from spleen or lymph nodes. By limiting dilution analysis, cytotoxic T lymphocyte (CTL) precursors specific for host antigens were rare in the extrathymic lymphoid tissues. In the thymus, by contrast, host-specific CTL precursors were only slightly less frequent than in normal parental strain mice. These host-specific CD8+ cells survived when BMC thymocytes were transferred intravenously to a neutral environment, i.e., to donor strain mice. When transferred to further BMC hosts, however, most of the host-reactive cells disappeared. Collectively, the data suggest that tolerance of CD8+ cells in BMC hosts occurs in both the intrathymic and extrathymic environments. In the thymus, contact with host antigens on thymic epithelial cells deletes CD8+ cells controlling helper-independent proliferative responses and in vivo effector functions but spares typical helper-dependent CTL precursors. After export from the thymus, most of the CTL precursors are eliminated after contacting host antigens on stromal cells in the extrathymic environment.

  10. Analysis of the cloverleaf element in a human rhinovirus type 14/poliovirus chimera: correlation of subdomain D structure, ternary protein complex formation and virus replication.

    Science.gov (United States)

    Rieder, Elizabeth; Xiang, Wenkai; Paul, Aniko; Wimmer, Eckard

    2003-08-01

    RNA genomes of enteroviruses and rhinoviruses contain a 5'-terminal structure, the cloverleaf (CL), which serves as signal in RNA synthesis. Substitution of the poliovirus [PV1(M)] CL with that of human rhinovirus type 2 (HRV2) was shown previously to produce a viable chimeric PV, whereas substitution with the HRV14 CL produced a null phenotype. Fittingly, the HRV14 CL failed to form a complex with PV-specific proteins 3CD(pro)-3AB or 3CD(pro)-PCBP2, considered essential for RNA synthesis. It was reported previously (Rohll et al., J Virol 68, 4384-4391, 1994) that the major determinant for the null phenotype of a PV/HRV14 chimera resides in subdomain Id of the HRV14 CL. Using a chimeric PV/HRV14 CL in the context of the PV genome, stem-loop Id of HRV14 CL was genetically dissected. It contains the sequence C(57)UAU(60)-G, the underlined nucleotides forming the loop that is shorter by 1 nt when compared to the corresponding PV structure (UUGC(60)GG). Insertion of a G nucleotide to form a tetra loop (C(57)UAU(60)GG(61)) did not rescue replication of the chimera. However, an additional mutation at position 60 (C(57)UAC(60)GG(61)) yielded a replicating genome. Only the mutant PV/HRV14 CL with the UAC(60)G tetra loop formed ternary complexes efficiently with either PV proteins 3CD(pro)-3AB or 3CD(pro)-PCBP2. Thus, in the context of PV RNA synthesis, the presence of a tetra loop in subdomain D of the CL per se is not sufficient for function. The sequence and, consequently, the structure of the tetra loop plays an essential role. Biochemical assays demonstrated that the function of the CL element and the function of the cis-acting replication element in the 3D(pol)-3CD(pro)-dependent uridylylation of VPg are not linked.

  11. Acute serum amyloid A induces migration, angiogenesis, and inflammation in synovial cells in vitro and in a human rheumatoid arthritis/SCID mouse chimera model.

    LENUS (Irish Health Repository)

    Connolly, Mary

    2010-06-01

    Serum amyloid A (A-SAA), an acute-phase protein with cytokine-like properties, is expressed at sites of inflammation. This study investigated the effects of A-SAA on chemokine-regulated migration and angiogenesis using rheumatoid arthritis (RA) cells and whole-tissue explants in vitro, ex vivo, and in vivo. A-SAA levels were measured by real-time PCR and ELISA. IL-8 and MCP-1 expression was examined in RA synovial fibroblasts, human microvascular endothelial cells, and RA synovial explants by ELISA. Neutrophil transendothelial cell migration, cell adhesion, invasion, and migration were examined using transwell leukocyte\\/monocyte migration assays, invasion assays, and adhesion assays with or without anti-MCP-1\\/anti-IL-8. NF-kappaB was examined using a specific inhibitor and Western blotting. An RA synovial\\/SCID mouse chimera model was used to examine the effects of A-SAA on cell migration, proliferation, and angiogenesis in vivo. High expression of A-SAA was demonstrated in RA patients (p < 0.05). A-SAA induced chemokine expression in a time- and dose-dependent manner (p < 0.05). Blockade with anti-scavenger receptor class B member 1 and lipoxin A4 (A-SAA receptors) significantly reduced chemokine expression in RA synovial tissue explants (p < 0.05). A-SAA induced cell invasion, neutrophil-transendothelial cell migration, monocyte migration, and adhesion (all p < 0.05), effects that were blocked by anti-IL-8 or anti-MCP-1. A-SAA-induced chemokine expression was mediated through NF-kappaB in RA explants (p < 0.05). Finally, in the RA synovial\\/SCID mouse chimera model, we demonstrated for the first time in vivo that A-SAA directly induces monocyte migration from the murine circulation into RA synovial grafts, synovial cell proliferation, and angiogenesis (p < 0.05). A-SAA promotes cell migrational mechanisms and angiogenesis critical to RA pathogenesis.

  12. An Engineered PrPsc-like Molecule from the Chimera of Mammalian Prion Protein and Yeast Ure2p Prion-inducing Domain

    Institute of Scientific and Technical Information of China (English)

    Shao-Man YIN; Man-Sun SY; Po TIEN

    2004-01-01

    Production of the pathogenic prion isoform prpsc-like molecules is thought to be useful forunderstanding the mysterious mechanism of conformational conversion process of prion diseases andproving the "protein-only" hypothesis. In this report, an engineered PrPsc-like conformation was producedfrom a chimera of mammalian bovine prion protein (bPrP) and yeast Ure2p prion-inducing domain (UPrD).Compared with the normal form of bPrP, the engineered recombinant protein, termed bPrP-UPrD,spontaneously aggregated into ordered fibrils under physiological condition, displaying amyloid-likecharacteristics, such as fibrillar morphology, birefringence upon binding to Congo red and increasedfluorescence intensity with Thioflavine T. Limited resistance to protease K digestion and CD spectroscopyexperiments suggested that the structure of bPrP-UPrD had been changed, and adopted a new, high contentβ-sheet conformation during the fibrils formation. Moreover, bPrP-UPrD amyloid fibrils could recruit moresoluble forms into the aggregates. Therefore, the engineered molecules could mimic significant behaviors ofPrPsc and will be helpful for further understanding the mechanism of conformational conversion process.

  13. An Engineered PrPsc-like Molecule from the Chimera of Mammalian Prion Protein and Yeast Ure2p Prion-inducing Domain

    Institute of Scientific and Technical Information of China (English)

    Shao-ManYIN; Man-SunSY; PoTIEN

    2004-01-01

    Production of the pathogenic prion isoform PrPsc-like molecules is thought to be useful forunderstanding the mysterious mechanism of conformational conversion process of prion diseases andproving the "protein-only" hypothesis. In this report, an engineered PrPsc-like conformation was producedfrom a chimera of mammalian bovine prion protein (bPrP) and yeast Ure2p prion-inducing domain (UPrD).Compared with the normal form of bPrP, the engineered recombinant protein, termed bPrP-UPrD,spontaneously aggregated into ordered fibrils under physiological condition, displaying amyloid-likecharacteristics, such as fibrillar morphology, birefringence upon binding to Congo red and increasedfluorescence intensity with Thioflavine T. Limited resistance to protease K digestion and CD spectroscopyexperiments suggested that the structure of bPrP-UPrD had been changed, and adopted a new, high contentB-sheet conformation during the fibrils formation. Moreover, bPrP-UPrD amyloid fibrils could recruit moresoluble forms into the aggregates. Therefore, the engineered molecules could mimic significant behaviors of PrPse and will be helpful for further understanding the mechanism of conformational conversion process.

  14. Design of potent inhibitors of human RAD51 recombinase based on BRC motifs of BRCA2 protein: modeling and experimental validation of a chimera peptide.

    KAUST Repository

    Nomme, Julian

    2010-08-01

    We have previously shown that a 28-amino acid peptide derived from the BRC4 motif of BRCA2 tumor suppressor inhibits selectively human RAD51 recombinase (HsRad51). With the aim of designing better inhibitors for cancer treatment, we combined an in silico docking approach with in vitro biochemical testing to construct a highly efficient chimera peptide from eight existing human BRC motifs. We built a molecular model of all BRC motifs complexed with HsRad51 based on the crystal structure of the BRC4 motif-HsRad51 complex, computed the interaction energy of each residue in each BRC motif, and selected the best amino acid residue at each binding position. This analysis enabled us to propose four amino acid substitutions in the BRC4 motif. Three of these increased the inhibitory effect in vitro, and this effect was found to be additive. We thus obtained a peptide that is about 10 times more efficient in inhibiting HsRad51-ssDNA complex formation than the original peptide.

  15. Protein nanopore-based, single-molecule exploration of copper binding to an antimicrobial-derived, histidine-containing chimera peptide.

    Science.gov (United States)

    Mereuta, Loredana; Schiopu, Irina; Asandei, Alina; Park, Yoonkyung; Hahm, Kyung-Soo; Luchian, Tudor

    2012-12-11

    Metal ions binding exert a crucial influence upon the aggregation properties and stability of peptides, and the propensity of folding in various substates. Herein, we demonstrate the use of the α-HL protein as a powerful nanoscopic tool to probe Cu(2+)-triggered physicochemical changes of a 20 aminoacids long, antimicrobial-derived chimera peptide with a His residue as metal-binding site, and simultaneously dissect the kinetics of the free- and Cu(2+)-bound peptide interaction to the α-HL pore. Combining single-molecule electrophysiology on reconstituted lipid membranes and fluorescence spectroscopy, we show that the association rate constant between the α-HL pore and a Cu(2+)-free peptide is higher than that of a Cu(2+)-complexed peptide. We posit that mainly due to conformational changes induced by the bound Cu(2+) on the peptide, the resulting complex encounters a higher energy barrier toward its association with the protein pore, stemming most likely from an extra entropy cost needed to fit the Cu(2+)-complexed peptide within the α-HL lumen region. The lower dissociation rate constant of the Cu(2+)-complexed peptide from α-HL pore, as compared to that of Cu(2+)-free peptide, supports the existence of a deeper free energy well for the protein interaction with a Cu(2+)-complexed peptide, which may be indicative of specific Cu(2+)-mediated contributions to the binding of the Cu(2+)-complexed peptide within the pore lumen.

  16. Autosomal P[ovoD1] dominant female-sterile insertions in Drosophila and their use in generating germ-line chimeras.

    Science.gov (United States)

    Chou, T B; Noll, E; Perrimon, N

    1993-12-01

    The 'dominant female-sterile' technique used to generate germ-line mosaics in Drosophila is a powerful tool to determine the tissue specificity (germ line versus somatic) of recessive female-sterile mutations as well as to analyze the maternal effect of recessive zygotic lethal mutations. This technique requires the availability of germ-line-dependent, dominant female-sterile (DFS) mutations that block egg laying but do not affect viability. To date only one X-linked mutation, ovoD1 has been isolated that completely fulfills these criteria. Thus the 'DFS technique' has been largely limited to the X-chromosome. To extend this technique to the autosomes, we have cloned the ovoD1 mutation into a P-element vector and recovered fully expressed P[ovoD1] insertions on each autosomal arm. We describe the generation of these P[ovoD1] strains as well as demonstrate their use in generating germ-line chimeras. Specifically, we show that the Gap1 gene, which encodes a Drosophila homologue of mammalian GTPase-activating protein, is required in somatic follicle cells for embryonic dorsoventral polarity determination.

  17. Expression of sex-specific molecular markers in clones of bipartite allophenic nemertines produced by somatic embryogenesis from Lineus sanguineus male/female chimera fragments.

    Science.gov (United States)

    Tarpin, M; Bierne, J

    1995-04-01

    SDS-PAGE electrophoresis showed major sex-specific proteins in sexually maturing and mature Lineus sanguineus. These "egg-specific" (145, 78 and 40 kDa) and "sperm-specific" (55,52 and 28 kDa) proteins are useful for studying sex differentiation in bilaterally allophenic worms produced by asexual reproduction of bipartite male/female chimeric worms. This study was carried out on 2 symmetrical clones of bilaterally allophenic worms, derived by somatic embryogenesis from fragments transected from chimeras obtained by exchange-grafting lateral body halves of male and female specimens, and from their asexually-derived progeny. The electrophoretic patterns of proteins extracted from sexually immature, maturing and mature allophenic animals from the 5th to the 19th year of cloning, showed the presence of all female-specific markers and the absence of male-specific markers. There was also complete biochemical feminization of the male halves. The synthesis of the only egg-specific molecules in initially male lateral body halves means that the long-term cloning results in the total repression of genes encoding sperm-specific proteins, since genetically male determinant-bearing cells can randomly re-express the testis characteristic as fertile but rudimentary male gonads.

  18. Surface functionalization of inorganic nano-crystals with fibronectin and E-cadherin chimera synergistically accelerates trans-gene delivery into embryonic stem cells.

    Science.gov (United States)

    Kutsuzawa, K; Chowdhury, E H; Nagaoka, M; Maruyama, K; Akiyama, Y; Akaike, T

    2006-11-24

    Stem cells holding great promises in regenerative medicine have the potential to be differentiated to a specific cell type through genetic manipulation. However, conventional ways of gene transfer to such progenitor cells suffer from a number of disadvantages particularly involving safety and efficacy issues. Here, we report on the development of a bio-functionalized inorganic nano-carrier of DNA by embedding fibronectin and E-cadherin chimera on the carrier, leading to its high affinity interactions with embryonic stem cell surface and accelerated trans-gene delivery for subsequent expression. While only apatite nano-particles were very inefficient in transfecting embryonic stem cells, fibronectin-anchored particles and to a more significant extent, fibronectin and E-cadherin-Fc-associated particles dramatically enhanced trans-gene delivery with a value notably higher than that of commercially available lipofection system. The involvement of both cell surface integrin and E-cadherin in mediating intracellular localization of the hybrid carrier was verified by blocking integrin binding site with excess free fibronectin and up-regulating both integrin and E-cadherin through PKC activation. Thus, the new establishment of a bio-functional hybrid gene-carrier would promote and facilitate development of stem cell-based therapy in regenerative medicine.

  19. Anatomical structure of leaf sectors with different resistance to powdery mildew (Erisiphe cruciferarum Opiz ex. L. Junell in winter rapeseed chimera

    Directory of Open Access Journals (Sweden)

    J. Cebrat

    2014-02-01

    Full Text Available The subject of the study was a sectorial chimera of dihaploid winter rapeseed, obtained with the help of gamma ray treatment (30 Gy during shoot cloning in vitro. One sector of the plant was infected by Erisiphe cruciferarum Opiz ex. L. Junell and the other one was resistant. The anatomical structure of a leaf, divided into the two sectors along the midrib, was studied. The infected part of the leaf blade was thinner and built of a smaller number of palisade and spongy mesophyll cell layers. The size of cells in this sector, both in the epidermis and in the mesophyll, as well as the size of nuclei, chloroplasts and intercellular spaces were bigger than those in the resistant portion. On the other hand, the stomata in the infected segment were smaller but their number was higher than that in the healthy part. The study made it possible to analyse the relation between the anatomical structure of the host plant and the pathogen.

  20. DYNAMICS OF SOMATIC CELLLINEAGE COMPETITION IN CHIMERAS OF Hydractinia symbiolongicarpus (CNIDARIA: HYDROZOA Dinámica de competencia entre líneas celulares somáticas en quimeras de Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa

    Directory of Open Access Journals (Sweden)

    RYAN S SCHWARZ

    Full Text Available Sessile colonial invertebrates often fuse with conspecifics to form chimeras. Chimerism represents an unequivocal instance of withinindividual selection where genetically different celllineages compete for representation in the somatic and gametic pools. We analyzed temporal and spatial variations in somatic celllineage composition of laboratoryestablished chimeras of the hydroid Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa. Using three clones with different allotypic specificities (i.e., two rejecting one another but fusing with a third one, we established two classes of twoway chimeras, a single threeway chimera class, and an incompatible interaction as control. Chimeras were sampled at five time intervals for a year. Celllineages in samples were identified by polyp fusibility assays against tester colonies of known fusibility. The cell lineages composing the chimeras showed a differential competitive ability, with one of them representing close to 80% by the end of the study. Rare celllineages stabilized at low frequencies but preserved their ability to gain somatic representation and to colonize distant parts of the chimera. This behavior characterizes cell parasites. As a consequence of the reproductive plasticity of most colonial invertebrates, celllineage variability may be transmitted to the offspring both sexually and asexually. Successful somatic competitors are expected to be preferentially transmitted asexually, whereas cell parasites would be preferentially transmitted sexuallyLos invertebrados coloniales y sésiles con frecuencia se fusionan con conespecíficos para formar quimeras. Estas quimeras son un ejemplo de selección natural actuando al interior del individuo en donde células genéticamente distintas compiten por acceso tanto a la línea somática como a la germinal. En este estudio se analizaron las variaciones temporal y espacial de linajes celulares somáticos en quimeras establecidas en el laboratorio del

  1. Dynamics of Somatic Cell-Lineage Competition in Chimeras of Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa Dinámica de competencia entre líneas celulares somáticas en quimeras de Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa

    Directory of Open Access Journals (Sweden)

    Schwarz Ryan S.

    2007-12-01

    Full Text Available Sessile colonial invertebrates often fuse with conspecifics to form chimeras. Chimerism represents an unequivocal instance of withinindividual selection where genetically different celllineages compete for representation in the somatic and gametic pools. We analyzed temporal and spatial variations in somatic celllineage composition of laboratoryestablished chimeras of the hydroid Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa. Using three clones with different allotypic specificities (i.e., two rejecting one another but fusing with a third one, we established two classes of twoway chimeras, a single threeway chimera class, and an incompatible interaction as control. Chimeras were sampled at five time intervals for a year. Celllineages in samples were identified by polyp fusibility assays against tester colonies of known fusibility. The cell lineages composing the chimeras showed a differential competitive ability, with one of them representing close to 80% by the end of the study. Rare celllineages stabilized at low frequencies but preserved their ability to gain somatic representation and to colonize distant parts of the chimera. This behavior characterizes cell parasites. As a consequence of the reproductive plasticity of most colonial invertebrates, celllineage variability may be transmitted to the offspring both sexually and asexually. Successful somatic competitors are expected to be preferentially transmitted asexually, whereas cell parasites would be preferentially transmitted sexually.Los invertebrados coloniales y sésiles con frecuencia se fusionan con conespecíficos para formar quimeras. Estas quimeras son un ejemplo de selección natural actuando al interior del individuo en donde células genéticamente distintas compiten por acceso tanto a la línea somática como a la germinal. En este estudio se analizaron las variaciones temporal y espacial de linajes celulares somáticos en quimeras establecidas en el

  2. Anti-CD20 single chain variable antibody fragment-apolipoprotein A-I chimera containing nanodisks promote targeted bioactive agent delivery to CD20-positive lymphomas.

    Science.gov (United States)

    Crosby, Natasha M; Ghosh, Mistuni; Su, Betty; Beckstead, Jennifer A; Kamei, Ayako; Simonsen, Jens B; Luo, Bing; Gordon, Leo I; Forte, Trudy M; Ryan, Robert O

    2015-08-01

    A fusion protein comprising an α-CD20 single chain variable fragment (scFv) antibody, a spacer peptide, and human apolipoprotein (apo) A-I was constructed and expressed in Escherichia coli. The lipid interaction properties intrinsic to apoA-I as well as the antigen recognition properties of the scFv were retained by the chimera. scFv•apoA-I was formulated into nanoscale reconstituted high-density lipoprotein particles (termed nanodisks; ND) and incubated with cultured cells. α-CD20 scFv•apoA-I ND bound to CD20-positive non-Hodgkins lymphoma (NHL) cells (Ramos and Granta) but not to CD20-negative T lymphocytes (i.e., Jurkat). Binding to NHL cells was partially inhibited by pre-incubation with rituximab, a monoclonal antibody directed against CD20. Confocal fluorescence microscopy analysis of Granta cells following incubation with α-CD20 scFv•apoA-I ND formulated with the intrinsically fluorescent hydrophobic polyphenol, curcumin, revealed α-CD20 scFv•apoA-I localizes to the cell surface, while curcumin off-loads and gains entry to the cell. Compared to control incubations, viability of cultured NHL cells was decreased upon incubation with α-CD20 scFv•apoA-I ND harboring curcumin. Thus, formulation of curcumin ND with α-CD20 scFv•apoA-I as the scaffold component confers cell targeting and enhanced bioactive agent delivery, providing a strategy to minimize toxicity associated with chemotherapeutic agents.

  3. Chimeras of mature pediocin PA-1 fused to the signal peptide of enterocin P permits the cloning, production, and expression of pediocin PA-1 in Lactococcus lactis.

    Science.gov (United States)

    Martín, María; Gutiérrez, Jorge; Criado, Raquel; Herranz, Carmen; Cintas, Luis M; Hernández, Pablo E

    2007-12-01

    Chimeras of pediocin PA-1 (PedA-1), a bacteriocin produced by Pediococcus acidilactici PLBH9, fused to the signal peptide of enterocin P (EntP), a sec-dependent bacteriocin produced by Enterococcus faecium P13, permitted the production of PedA-1 in Lactococcus lactis. Chimeric genes encoding the EntP signal peptide (SP(entP)) fused to mature PedA-1 (pedA), with or without its immunity gene (pedB), were cloned into the expression vector pMG36c to generate the recombinant plasmids pMPP9 (SP(entP):pedA) and pMPP14i (SP(entP):pedA + pedB). Transformation of competent L. lactis subsp. lactis IL1403, L. lactis subsp. cremoris NZ9000, and L. lactis subsp. lactis DPC5598 with the recombinant plasmids has permitted the detection and quantitation of PedA-1 and the coproduction of nisin A and PedA-1 in supernatants of producer cells with specific anti-PedA-1 antibodies and a noncompetitive indirect enzyme-linked immunosorbent assay. Recombinant L. lactis hosts carrying pMPP9 or pMPP14i displayed antimicrobial activity, suggesting that mature PedA-1 fused to SP(EntP) is the minimum requirement for the synthesis, processing, and secretion of biologically active PedA-1 in L. lactis. However, the production and antimicrobial activity of the PedA-1 produced by L. lactis was lower than that produced by the P. acidilactici control strains.

  4. Bridge Technology with TSH Receptor Chimera for Sensitive Direct Detection of TSH Receptor Antibodies Causing Graves' Disease: Analytical and Clinical Evaluation.

    Science.gov (United States)

    Frank, C U; Braeth, S; Dietrich, J W; Wanjura, D; Loos, U

    2015-11-01

    Graves' disease is caused by stimulating autoantibodies against the thyrotropin receptor inducing uncontrolled overproduction of thyroid hormones. A Bridge Assay is presented for direct detection of these thyroid-stimulating immunoglobulins using thyrotropin receptor chimeras. A capture receptor, formed by replacing aa residues 261-370 of the human thyrotropin receptor with residues 261-329 from rat lutropin/choriogonadotropin receptor and fixed to microtiter plates, binds one arm of the autoantibody. The second arm bridges to the signal receptor constructed from thyrotropin receptor (aa 21-261) and secretory alkaline phosphatase (aa 1-519) inducing chemiluminescence. The working range of the assay is from 0.3 IU/l to 50 IU/l with a cutoff of 0.54 IU/l and functional sensitivity of 0.3 IU/l. Sensitivity and specificity are 99.8 and 99.1%, respectively, with a diagnostic accuracy of 0.998. The low grey zone is from 0.3-0.54 IU/l. The stimulatory character of the assayed antibodies is shown through a good correlation (r=0.7079, pGraves' disease, titers are increased in associated eye disease. In 3 hypothyroid patients with sera positive in the thyrotropin receptor competition assay and in the blocking bioassay, antibodies are not detected by the Bridge Assay, while the monoclonal blocking antibody K1-70 was detected. In Hashimoto disease thyrotropin receptor autoantibodies are detected in some patients, but not in goiter. This Bridge Assay delivers good diagnostic accuracy for identification of Graves' disease patients. Its high sensitivity may facilitate early detection of onset, remission, or recurrence of Graves' disease enabling timely adaption of the treatment.Human genes: TSHR, Homo sapiens, acc. no. M31774.1.

  5. Regulation of FSHβ induction in LβT2 cells by BMP2 and an Activin A/BMP2 chimera, AB215.

    Science.gov (United States)

    Jung, Jae Woo; Ahn, Chihoon; Shim, Sun Young; Gray, Peter C; Kwiatkowski, Witek; Choe, Senyon

    2014-10-01

    Activins and bone morphogenetic proteins (BMPs) share activin type 2 signaling receptors but utilize different type 1 receptors and Smads. We designed AB215, a potent BMP2-like Activin A/BMP2 chimera incorporating the high-affinity type 2 receptor-binding epitope of Activin A. In this study, we compare the signaling properties of AB215 and BMP2 in HEK293T cells and gonadotroph LβT2 cells in which Activin A and BMP2 synergistically induce FSHβ. In HEK293T cells, AB215 is more potent than BMP2 and competitively blocks Activin A signaling, while BMP2 has a partial blocking activity. Activin A signaling is insensitive to BMP pathway antagonism in HEK293T cells but is strongly inhibited by constitutively active (CA) BMP type 1 receptors. By contrast, the potencies of AB215 and BMP2 are indistinguishable in LβT2 cells and although AB215 blocks Activin A signaling, BMP2 has no inhibitory effect. Unlike HEK293T, Activin A signaling is strongly inhibited by BMP pathway antagonism in LβT2 cells but is largely unaffected by CA BMP type 1 receptors. BMP2 increases phospho-Smad3 levels in LβT2 cells, in both the absence and the presence of Activin A treatment, and augments Activin A-induced FSHβ. AB215 has the opposite effect and sharply decreases basal phospho-Smad3 levels and blocks Smad2 phosphorylation and FSHβ induction resulting from Activin A treatment. These findings together demonstrate that while AB215 activates the BMP pathway, it has opposing effects to those of BMP2 on FSHβ induction in LβT2 cells apparently due to its ability to block Activin A signaling.

  6. Directed Evolution of a Cyclized Peptoid-Peptide Chimera against a Cell-Free Expressed Protein and Proteomic Profiling of the Interacting Proteins to Create a Protein-Protein Interaction Inhibitor.

    Science.gov (United States)

    Kawakami, Takashi; Ogawa, Koji; Hatta, Tomohisa; Goshima, Naoki; Natsume, Tohru

    2016-06-17

    N-alkyl amino acids are useful building blocks for the in vitro display evolution of ribosomally synthesized peptides because they can increase the proteolytic stability and cell permeability of these peptides. However, the translation initiation substrate specificity of nonproteinogenic N-alkyl amino acids has not been investigated. In this study, we screened various N-alkyl amino acids and nonamino carboxylic acids for translation initiation with an Escherichia coli reconstituted cell-free translation system (PURE system) and identified those that efficiently initiated translation. Using seven of these efficiently initiating acids, we next performed in vitro display evolution of cyclized peptidomimetics against an arbitrarily chosen model human protein (β-catenin) cell-free expressed from its cloned cDNA (HUPEX) and identified a novel β-catenin-binding cyclized peptoid-peptide chimera. Furthermore, by a proteomic approach using direct nanoflow liquid chromatography-tandem mass spectrometry (DNLC-MS/MS), we successfully identified which protein-β-catenin interaction is inhibited by the chimera. The combination of in vitro display evolution of cyclized N-alkyl peptidomimetics and in vitro expression of human proteins would be a powerful approach for the high-speed discovery of diverse human protein-targeted cyclized N-alkyl peptidomimetics.

  7. The search for the chimera

    CERN Document Server

    Randi, J

    1991-01-01

    Session 1 Mr. Randi will give an update of his lecture to the American Physical Society on the occasion of his award of the 1989 Forum Prize. The citation said: "for his unique defense of Science and the scientific method in many disciplines, including physics, against pseudoscience, frauds and charlatans. His use of scientific techniques has contributed to refuting suspicious and fraudulent claims of paranormal results. He has contributed significantly to public understanding of important issues where science and society interact". He is a professional magician and author of many books. He worked with John Maddox, the Editor of Nature to investigate the claims of "water with memory".

  8. Cloning, production, and functional expression of the bacteriocin sakacin A (SakA) and two SakA-derived chimeras in lactic acid bacteria (LAB) and the yeasts Pichia pastoris and Kluyveromyces lactis.

    Science.gov (United States)

    Jiménez, Juan J; Borrero, Juan; Diep, Dzung B; Gútiez, Loreto; Nes, Ingolf F; Herranz, Carmen; Cintas, Luis M; Hernández, Pablo E

    2013-09-01

    Mature sakacin A (SakA, encoded by sapA) and its cognate immunity protein (SakI, encoded by sapiA), and two SakA-derived chimeras mimicking the N-terminal end of mature enterocin P (EntP/SakA) and mature enterocin A (EntA/SakA) together with SakI, were fused to different signal peptides (SP) and cloned into the protein expression vectors pNZ8048 and pMG36c for evaluation of their production and functional expression by different lactic acid bacteria. The amount, antimicrobial activity, and specific antimicrobial activity of SakA and its chimeras produced by Lactococcus lactis subsp. cremoris NZ9000 depended on the SP and the expression vector. Only L. lactis NZ9000 (pNUPS), producing EntP/SakA, showed higher bacteriocin production and antimicrobial activity than the natural SakA-producer Lactobacillus sakei Lb706. The lower antimicrobial activity of the SakA-producer L. lactis NZ9000 (pNUS) and that of the EntA/SakA-producer L. lactis NZ9000 (pNUAS) could be ascribed to secretion of truncated bacteriocins. On the other hand, of the Lb. sakei Lb706 cultures transformed with the pMG36c-derived vectors only Lb. sakei Lb706 (pGUS) overproducing SakA showed a higher antimicrobial activity than Lb. sakei Lb706. Finally, cloning of SakA and EntP/SakA into pPICZαA and pKLAC2 permitted the production of SakA and EntP/SakA by recombinant Pichia pastoris X-33 and Kluyveromyces lactis GG799 derivatives although their antimicrobial activity was lower than expected from their production.

  9. Chemical synthesis and 1H-NMR 3D structure determination of AgTx2-MTX chimera, a new potential blocker for Kv1.2 channel, derived from MTX and AgTx2 scorpion toxins.

    Science.gov (United States)

    Pimentel, Cyril; M'Barek, Sarrah; Visan, Violetta; Grissmer, Stephan; Sampieri, François; Sabatier, Jean-Marc; Darbon, Hervé; Fajloun, Ziad

    2008-01-01

    Agitoxin 2 (AgTx2) is a 38-residue scorpion toxin, cross-linked by three disulfide bridges, which acts on voltage-gated K(+) (Kv) channels. Maurotoxin (MTX) is a 34-residue scorpion toxin with an uncommon four-disulfide bridge reticulation, acting on both Ca(2+)-activated and Kv channels. A 39-mer chimeric peptide, named AgTx2-MTX, was designed from the sequence of the two toxins and chemically synthesized. It encompasses residues 1-5 of AgTx2, followed by the complete sequence of MTX. As established by enzyme cleavage, the new AgTx2-MTX molecule displays half-cystine pairings of the type C1-C5, C2-C6, C3-C7, and C4-C8, which is different from that of MTX. The 3D structure of AgTx2-MTX solved by (1)H-NMR, revealed both alpha-helical and beta-sheet structures, consistent with a common alpha/beta scaffold of scorpion toxins. Pharmacological assays of AgTx2-MTX revealed that this new molecule is more potent than both original toxins in blocking rat Kv1.2 channel. Docking simulations, performed with the 3D structure of AgTx2-MTX, confirmed this result and demonstrated the participation of the N-terminal domain of AgTx2 in its increased affinity for Kv1.2 through additional molecular contacts. Altogether, the data indicated that replacement of the N-terminal domain of MTX by the one of AgTx2 in the AgTx2-MTX chimera results in a reorganization of the disulfide bridge arrangement and an increase of affinity to the Kv1.2 channel.

  10. Chemical synthesis and 1H-NMR 3D structure determination of AgTx2-MTX chimera, a new potential blocker for Kv1.2 channel, derived from MTX and AgTx2 scorpion toxins

    Science.gov (United States)

    Pimentel, Cyril; M'Barek, Sarrah; Visan, Violetta; Grissmer, Stephan; Sampieri, François; Sabatier, Jean-Marc; Darbon, Hervé; Fajloun, Ziad

    2008-01-01

    Agitoxin 2 (AgTx2) is a 38-residue scorpion toxin, cross-linked by three disulfide bridges, which acts on voltage-gated K+ (Kv) channels. Maurotoxin (MTX) is a 34-residue scorpion toxin with an uncommon four-disulfide bridge reticulation, acting on both Ca2+-activated and Kv channels. A 39-mer chimeric peptide, named AgTx2-MTX, was designed from the sequence of the two toxins and chemically synthesized. It encompasses residues 1–5 of AgTx2, followed by the complete sequence of MTX. As established by enzyme cleavage, the new AgTx2-MTX molecule displays half-cystine pairings of the type C1–C5, C2–C6, C3–C7, and C4–C8, which is different from that of MTX. The 3D structure of AgTx2-MTX solved by 1H-NMR, revealed both α-helical and β-sheet structures, consistent with a common α/β scaffold of scorpion toxins. Pharmacological assays of AgTx2-MTX revealed that this new molecule is more potent than both original toxins in blocking rat Kv1.2 channel. Docking simulations, performed with the 3D structure of AgTx2-MTX, confirmed this result and demonstrated the participation of the N-terminal domain of AgTx2 in its increased affinity for Kv1.2 through additional molecular contacts. Altogether, the data indicated that replacement of the N-terminal domain of MTX by the one of AgTx2 in the AgTx2-MTX chimera results in a reorganization of the disulfide bridge arrangement and an increase of affinity to the Kv1.2 channel. PMID:18042681

  11. Solvable Model of Spiral Wave Chimeras

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Laing, Carlo R.; Strogatz, Steven H.

    2010-01-01

    Spiral waves are ubiquitous in two-dimensional systems of chemical or biological oscillators coupled locally by diffusion. At the center of such spirals is a phase singularity, a topological defect where the oscillator amplitude drops to zero. But if the coupling is nonlocal, a new kind of spiral...

  12. Chimera multiscale simulation of complex flowing matter

    CERN Document Server

    Succi, Sauro

    2016-01-01

    We discuss a unified mesoscale framework for the simulation of complex states of flowing matter across scales of motion which requires no explicit coupling between different macro-meso-micro levels. The idea is illustrated through selected examples of complex flows at the micro and nanoscale.

  13. Patenting humans: clones, chimeras, and biological artifacts.

    Science.gov (United States)

    Hurlbut, William B

    2005-01-01

    The momentum of advances in biology is evident in the history of patents on life forms. As we proceed forward with greater understanding and technological control of developmental biology there will be many new and challenging dilemmas related to patenting of human parts and partial trajectories of human development. These dilemmas are already evident in the current conflict over the moral status of the early human embryo. In this essay, recent evidence from embryological studies is considered and the unbroken continuity of organismal development initiated at fertilization is asserted as clear and reasonable grounds for moral standing. Within this frame of analysis, it is proposed that through a technique of Altered Nuclear Transfer, non-organismal entities might be created from which embryonic stem cells could be morally procured. Criteria for patenting of such non-organismal entities are considered.

  14. Effects of developmental stages of tetraploid embryos on mouse chimeras from embryonic stem cells%四倍体胚胎发育阶段对胚胎干细胞嵌合体小鼠制备的影响

    Institute of Scientific and Technical Information of China (English)

    吴兴龙; 张鹏; 赵虎; 王鹏博; 胡春超; 李相运

    2011-01-01

    目的 探讨四倍体胚胎发育阶段对胚胎干细胞(ES)嵌合体小鼠制备的影响.方法 通过2-细胞胚胎电融合法制备四倍体胚胎,采用显微注射方法将ES细胞分别注入1-细胞、4-细胞、囊胚3个发育阶段的四倍体胚胎中.所用ES细胞分别为杂交系B6D2F1×129/Sv和近交系C57BL/6J,经胚胎移植和剖腹产以获得ES小鼠.结果 实验表明,2-细胞胚胎电融合率为92.45%,4-细胞胚胎发育率为93.51%,囊胚发育率为90.42%.杂交ES细胞注射四倍体囊胚获得22只ES小鼠,效率显著高于近交系ES细胞以及其他发育阶段的四倍体胚胎,ES小鼠与B6D2F1×129/Sv杂交小鼠毛色一致且具有正常生殖能力.结论 四倍体胚胎的发育阶段显著影响ES小鼠的制备.%Objective To investigate the effects of developmental stages of tetraploid embryos on mouse chimeras from embryonic stem cells ( ES ).Methods Tetraploid embryo complementation and microinjection were utilized to produce ES mice that derived completely from ES cells.Tetraploid embryos were firstly prepared by electrofusion of 2-cell mouse embryos, and then embryonic stem ( ES ) cells with different genetic background ( hybrid or inbred ) were injected into tetraploid 1-cell, 4-cell, and blastocyst stage embryos.The injected embryos were transferred into uterine horns of pseudopregnant 2.5days female CDl mice.The CD1 mice were suhjected into cesarean sections after 16 days.Results Our data showed that 92.45% of 2-cell embryos were electrofused, 93.51% and 90.42% of the electrofused embryos developed to 4-cell and blastocyst stages, respectively.Blastocysts were injected with hybrid ES cells and 22 ES mice were obtained by Cesarean section.Blastocyst was more effective than 1-cell and 4-cell.ES mice had normal germline transmission capahility and the same coat color as the hybrid mice which hybrid ES cells were drived from.Conclusion The tetraploid embryo developmental stage is able to affect the ES mouse

  15. Peak Oil and other threatening peaks-Chimeras without substance

    Energy Technology Data Exchange (ETDEWEB)

    Radetzki, Marian, E-mail: marian@radetzki.bi [Lulea University of Technology (Sweden)

    2010-11-15

    The Peak Oil movement has widely spread its message about an impending peak in global oil production, caused by an inadequate resource base. On closer scrutiny, the underlying analysis is inconsistent, void of a theoretical foundation and without support in empirical observations. Global oil resources are huge and expanding, and pose no threat to continuing output growth within an extended time horizon. In contrast, temporary or prolonged supply crunches are indeed plausible, even likely, on account of growing resource nationalism denying access to efficient exploitation of the existing resource wealth.

  16. Peak Oil and other threatening peaks. Chimeras without substance

    Energy Technology Data Exchange (ETDEWEB)

    Radetzki, Marian [Luleaa University of Technology (Sweden)

    2010-11-15

    The Peak Oil movement has widely spread its message about an impending peak in global oil production, caused by an inadequate resource base. On closer scrutiny, the underlying analysis is inconsistent, void of a theoretical foundation and without support in empirical observations. Global oil resources are huge and expanding, and pose no threat to continuing output growth within an extended time horizon. In contrast, temporary or prolonged supply crunches are indeed plausible, even likely, on account of growing resource nationalism denying access to efficient exploitation of the existing resource wealth. (author)

  17. Chimera: A hybrid approach to numerical loop quantum cosmology

    CERN Document Server

    Diener, Peter; Singh, Parampreet

    2013-01-01

    The existence of a quantum bounce in isotropic spacetimes is a key result in loop quantum cosmology (LQC), which has been demonstrated to arise in all the models studied so far. In most of the models, the bounce has been studied using numerical simulations involving states which are sharply peaked and which bounce at volumes much larger than the Planck volume. An important issue is to confirm the existence of the bounce for states which have a wide spread, or which bounce closer to the Planck volume. Numerical simulations with such states demand large computational domains, making them very expensive and practically infeasible with the techniques which have been implemented so far. To overcome these difficulties, we present an efficient hybrid numerical scheme using the property that at the small spacetime curvature, the quantum Hamiltonian constraint in LQC, which is a difference equation with uniform discretization in volume, can be approximated by a Wheeler-DeWitt differential equation. By carefully choosi...

  18. Dynamic Camouflage Materials Based on Silk-Reflectin Chimeras

    Science.gov (United States)

    2012-08-01

    by flow coating and spin coating , and displayed colors due to thin film interference. The assemblies were ordered enough to exhibit diffractive...consisted of several different techniques prior to spin coating . First, various amounts of protein solution were drop casted onto different substrates...report the successful formation of smooth, reproducible thin films, using spin - coating deposition. Reflectin-based refCBA with different concentrations

  19. RNA Chimeras as a Gene Signature of Breast Cancer

    Science.gov (United States)

    2013-05-01

    TART END ::>PAN 960 960 959 957 948 947 947 944 941 938 937 931 929 926 926 917 916 912 910 910 909 901 894 889 RRR 887...1256 1229 1089 1084 1221 1218 1153 1204 1092 1170 1231 1201 1230 1149 1004 1211 1219 1307 1173 lZH 12~1 1011 16900259 169014𔄀

  20. The Sin of an Artist and the Chimeras of Art

    Directory of Open Access Journals (Sweden)

    Renansky A. L.

    2014-01-01

    Full Text Available The thematic structure of Fyodor Dostoyevsky’s novel “Netochka Nezvanova” is revealed in the article through the system of leitmotifs rising to elementary semantic oppositions. The topical opposition of high and low is traced throughout the semantics of space. The periphery of the story - the estate of a landowner, a music-lover, and its sacral centre - the ‘sunny’ home of Prince H. in St. Petersburg are brought together by the main character’s lifelong way. In Yegor Efimov’s biography, this is predetermined in the same way as the initiation of a fairytale hero is predestined. It should be emphasized that the unique temporal structure of “Netochka Nezvanova” is analyzed in this aspect for the first time. Like many other Dostoyevsky’s works, this particular story displays signs of “inoculations” from different poetic systems and other texts which form a complicated system of intertextual connections. The leading motif of the story belongs to the circle of the basic mythopoetic topic: Man’s temptation by Satan. The demon’s intrusion into Efimov’s life is especially well traced in his friendship with the Italian conductor and in inheriting the latter’s violin. The history of the violin is accompanied by the marginal demonic background created by the stable mythologem - “the Satan’s violin”. Within the borders of mythopoetic concept of music, an artist is a medium, a person who has the power to influence other people in the name of good or evil by supernatural forces. In this respect, the life story of Efremov the violinist can be compared to the adventures of a mythological “cultural hero” presented as a non-stop chain of events: meeting a magical sorcerer, receiving a magic weapon from him as a gift and the ensuing sequence of dreadful ordeals. Yegor Efimov’s life story is shown in the article against the background of the mythopoetic concept of music, as Man’s temptation by Satan, and in the historical and cultural context, as shattering a romantic myth about “a demonic artist”.

  1. Creating clones, kids & chimera: liberal democratic compromise at the crossroads.

    Science.gov (United States)

    Adams, Nathan A

    2004-01-01

    The objective of this article is to find middle ground between the supporters and opponents of biotechnology by perpetuating the existing legal compromise pertaining to the complete range of health and welfare doctrines relevant to the biotechnological industry. The author aspires neither to add to nor detract from this liberal democratic consensus, but to preserve its constitutive balance between positivism and natural law and over-regulation and under-regulation in the hopes of stabilizing new political fault lines developing around the few biotechnological innovations already grabbing headlines. The most feasible solution is to extend the existing liberal democratic compromise with respect to equal protection, reproductive rights, the First Amendment, human subject experimentation, patent law, and parental rights. This includes banning or monopolizing certain biotechnologies and extending substantive special respect to the ex vivo living human embryo. Biotechnology must not be left to regulate itself.

  2. RNA Chimeras as a Gene Signature of Breast Cancer

    Science.gov (United States)

    2014-06-01

    ESTs in the NCBI database contain such SHS, which on average has 6.4-6.5 nucleotides (nt) overlapped by the two partner genes (see the table above...human expression sequence tags (ESTs) deposited in different public databases, and obtained hundreds of putative trimeric ESTs. We then used NCBI ...mRNA collections in the NCBI database and obtained hundreds of putative trimeric ESTs. We then used the NCBI Blast and UCSC Blat browsers to analyze

  3. Hunting down the chimera of multiple disciplinarity in conservation science.

    Science.gov (United States)

    Pooley, Simon P; Mendelsohn, J Andrew; Milner-Gulland, E J

    2014-02-01

    The consensus is that both ecological and social factors are essential dimensions of conservation research and practice. However, much of the literature on multiple disciplinary collaboration focuses on the difficulties of undertaking it. This review of the challenges of conducting multiple disciplinary collaboration offers a framework for thinking about the diversity and complexity of this endeavor. We focused on conceptual challenges, of which 5 main categories emerged: methodological challenges, value judgments, theories of knowledge, disciplinary prejudices, and interdisciplinary communication. The major problems identified in these areas have proved remarkably persistent in the literature surveyed (c.1960-2012). Reasons for these failures to learn from past experience include the pressure to produce positive outcomes and gloss over disagreements, the ephemeral nature of many such projects and resulting lack of institutional memory, and the apparent complexity and incoherence of the endeavor. We suggest that multiple disciplinary collaboration requires conceptual integration among carefully selected multiple disciplinary team members united in investigating a shared problem or question. We outline a 9-point sequence of steps for setting up a successful multiple disciplinary project. This encompasses points on recruitment, involving stakeholders, developing research questions, negotiating power dynamics and hidden values and conceptual differences, explaining and choosing appropriate methods, developing a shared language, facilitating on-going communications, and discussing data integration and project outcomes. Although numerous solutions to the challenges of multiple disciplinary research have been proposed, lessons learned are often lost when projects end or experienced individuals move on. We urge multiple disciplinary teams to capture the challenges recognized, and solutions proposed, by their researchers while projects are in process. A database of well-documented case studies would showcase theories and methods from a variety of disciplines and their interactions, enable better comparative study and evaluation, and provide a useful resource for developing future projects and training multiple disciplinary researchers.

  4. Categorization of birds, mammals, and chimeras by pigeons.

    Science.gov (United States)

    Cook, Robert G; Wright, Anthony A; Drachman, Eric E

    2013-02-01

    Identifying critical features that control categorization of complex polymorphous pictures by animals remains a challenging and important problem. Toward this goal, experiments were conducted to isolate the properties controlling the categorization of two pictorial categories by pigeons. Pigeons were trained in a go/no-go task to categorize black and white line drawings of birds and mammals. They were then tested with a variety of familiar and novel exemplars of these categories to examine the features controlling this categorization. These tests suggested the pigeons were segregating and using the principal axis of orientation of the animal figures as the primary means of discriminating each category, although other categorical and item-specific cues were likely involved. This perceptual/cognitive reduction of the categorical stimulus space to a few visual features or dimensions is likely a characteristic of this species' processing of complex pictorial discrimination problems and is a critical property for theoretical accounts of this behavior.

  5. A healthy, female chimera with 46,XX/46,XY karyotype.

    NARCIS (Netherlands)

    Binkhorst, M.; Leeuw, N. de; Otten, B.J.

    2009-01-01

    We report a healthy and unambiguously female newborn, whose phenotypic sex contradicted the expected male sex based on previously performed prenatal cytogenetic analysis. Both 46,XX and 46,XY cells were detected in a villus sample, the former having been attributed to maternal cell contamination. Po

  6. Resurrecting the chimera: Progressions in parenting and peer processes.

    Science.gov (United States)

    Forgatch, Marion S; Snyder, James J; Patterson, Gerald R; Pauldine, Michael R; Chaw, Yvonne; Elish, Katie; Harris, Jasmine B; Richardson, Eric B

    2016-08-01

    This report uses 6-year outcomes of the Oregon Divorce Study to examine the processes by which parenting practices affect deviant peer association during two developmental stages: early to middle childhood and late childhood to early adolescence. The participants were 238 newly divorced mothers and their 5- to 8-year-old sons who were randomly assigned to Parent Management Training-Oregon Model (PMTO®) or to a no-treatment control group. Parenting practices, child delinquent behavior, and deviant peer association were repeatedly assessed from baseline to 6 years after baseline using multiple methods and informants. PMTO had a beneficial effect on parenting practices relative to the control group. Two stage models linking changes in parenting generated by PMTO to children's growth in deviant peer association were supported. During the early to middle childhood stage, the relationship of improved parenting practices on deviant peer association was moderated by family socioeconomic status (SES); effective parenting was particularly important in mitigating deviant peer association for lower SES families whose children experience higher densities of deviant peers in schools and neighborhoods. During late childhood and early adolescence, the relationship of improved parenting to youths' growth in deviant peer association was mediated by reductions in the growth of delinquency during childhood; higher levels of early delinquency are likely to promote deviant peer association through processes of selective affiliation and reciprocal deviancy training. The results are discussed in terms of multilevel developmental progressions of diminished parenting, child involvement in deviancy producing processes in peer groups, and increased variety and severity of antisocial behavior, all exacerbated by ecological risks associated with low family SES.

  7. Donor chimera model for tolerance induction in transplantation

    NARCIS (Netherlands)

    Rezaee, F.; Peppelenbosch, M.; Dashty, M.

    2013-01-01

    Tolerance induction is the basis of a successful transplantation with the goal being the re-establishment of homeostasis after transplantation. Non-autograft transplantation disrupts this maintenance drastically which would be avoided by administration of a novel procedure. At present, the blood gro

  8. Production of chicken chimeras by fusing blastodermal cells with electroporation

    Institute of Scientific and Technical Information of China (English)

    S.Aritomi; N.Fujihara

    2000-01-01

    Aim: To establish techniques for producing somatic and gennline chimeric chicken by transferring blastodennal cells fused with electroporation. Methods: Stage-X blastodermal cells isolated from freshly laid fertile unincubated white Leghom and Rhode Island red chicken eggs were fused with electroporation. The treated cell suspension was transferred to the recovery medium (DMEM containing 10% FBS) and was injected into the subgerminal cavity of recipient tmincubated embryos (stage X). Results: Of 177 recipient embryos injected with the fusing blastodermal cells, 6 (3.4%) survived to hatching. Somatic chimerism was examined in the melanocyte of the feather. The presence of feathers originating from the donor cell was observed in 1 bird (16.7%) out of the 6 hatched birds. After 21 days of incubation two birds out of five embryos were subjected to polymemse chain reaction (PCR) analysis for W-chromosome-specific DNA for each tissue. One bird possessed W-chromosome-specific DNA in the stomach, and the other exhibited the same DNA in the left and right gonads and other tissues, but not the stomach. Conclusion: Recipient embryo having electrofused blastodermal cells yields somatic and germline chimeric chickens more successfully.(Asian J Androl 2000 Dec;2:271-275)

  9. Detecting individual gravity modes in the Sun: Chimera or reality?

    CERN Document Server

    Garcia, Rafael A; Eff-Darwich, A; Garrido, R; Jimenez, A; Mathis, S; Mathur, S; Moya, A; Palle, P L; Regulo, C; Salabert, D; Sato, K; Suarez, J C; Turck-Chieze, S

    2009-01-01

    Over the past 15 years, our knowledge of the interior of the Sun has tremendously progressed by the use of helioseismic measurements. However, to go further in our understanding of the solar core, we need to measure gravity (g) modes. Thanks to the high quality of the Doppler-velocity signal measured by GOLF/SoHO, it has been possible to unveil the signature of the asymptotic properties of the solar g modes, thus obtaining a hint of the rotation rate in the core. However, the quest for the detection of individual g modes is not yet over. In this work, we apply the latest theoretical developments to guide our research using GOLF velocity time series. In contrary to what was thought till now, we are maybe starting to identify individual low-frequency g modes...

  10. 双色鸳鸯美人蕉中花青素合成关键基因的克隆与表达分析%Cloning and Expression Analysis of Anthocyanin Biosynthesis Genes from Red-Yellow Flower Chimera in Canna ge ne ralis

    Institute of Scientific and Technical Information of China (English)

    李军; 高广春; 李白

    2015-01-01

    The red-yellow flower chimera in Canna ge ne ralis (Canna ge ne ralis Bailey) was used as material and the chalcone synthase gene (CgCHS) and dihydroflavonol 4-reductase gene (CgDFR) were cloned using RT-PCR. The 549 bp and 570 bp fragment of CHS and DFR genes were cloned, sequence comparison showed that these genes share 70%to 95%identities with each previously reported corresponding genes. The expression patterns of CHS, DFR and CHI (chalcone isomerase) genes were analyzed by Real-time quantitative PCR (RT-qPCR). The results showed that the expression quantity of CHS and DFR genes was higher in red-part than in yellow-part, while CHI gene showed on the contrary. The expression of CHS and CHI genes increased in accordance with flower development in red-part, while in the yellow-part its expression increased in the earlier three developmental stages and then reduced in the fourth stage. The expression pattern of DFR gene was consistent with flower development both in the red- and yellow-parts. The expression pattern of these three genes in Canna ge ne ralis varied with different flower color were different with each other.%本研究以双色鸳鸯美人蕉为试材,采用RT-PCR技术扩增查尔酮合成酶基因(CHS)及二氢黄酮醇4-还原酶基因(DFR)序列,并利用RT-qPCR技术检测CHS、DFR及查尔酮异构酶基因(CHI)在双色鸳鸯美人蕉同一朵花不同颜色部位、不同发育时期的表达差异以及在不同花色美人蕉中的表达特性。结果显示:通过扩增分别获得了549 bp的CHS基因片段及570 bp的DFR基因片段,与红掌、百合等相应基因的同源性达70%~95%。基因表达分析表明,CHS及DFR在红色花瓣中的表达量高于黄色花瓣,CHI在黄色花瓣中的表达量高于红色花瓣;CHS与CHI在红色花瓣中随着发育表达量逐渐增大,在黄色花瓣随发育表达量呈先增加后减少的趋势;DFR在红色及黄色花瓣的发育后期表达量逐渐增大;在不同

  11. Immune function of mage-3 gene vaccine in human melanoma based on human/mouse chimera model%基于人/鼠嵌合模型的人黑色素瘤mage-3基因疫苗的免疫学作用

    Institute of Scientific and Technical Information of China (English)

    姜曼; 吴玉章; 倪兵

    2004-01-01

    AIM:To evaluate the immune effect of mage-3 gene vaccine in human melanoma by human/mouse chimera model.METHODS:Trimera animal model was established and evaluated.It was immunized by recombinant plasmid mage-3/pCI neo as vaccine.Killing activity of splenocyte cytotoxic T Lymphocyte(CTL) and mage-3 antibody specific in blood serum of the immune animal was detected.RESULTS:Quantity of human lymphocyte was discovered in the spleen and abdominal cavity of the established Trimera model.After vaccination,mage-3 antibody specific with the potency of 1: 256 was presented in Trimera model.CTL killing experiments in vitro of the immune animal reveal that the maximum killing rate to target cell LB373 of Spleen lymphocyte of the Trimera mice was about 50% after vaccination comparing with that of below 10% in control mice group. CONCLUSION:Mage-3 is an ideal tumour vaccine.It can stimulate specific cell and body fluid immunisation in humanized animal model.Therefore,it provides an experimental gist for clinical therapies in all kinds of tumour cells,which share same mage-3 antigen.%目的 :利用人 /鼠嵌合模型评价人黑色素瘤基因 mage-3基因疫苗的免疫效果. 方法 :建立并鉴定 Trimera动物模型,并用重组质粒 mage-3/pCI neo作为基因疫苗对其进行免疫.检测免疫动物脾细胞 CTL的杀伤活性和血清中 mage-3特异性抗体. 结果 :构建的 Trimera模型脾脏和腹腔中出现了大量的人淋巴细胞.接种后, Trimera模型体内出现了效价为 1: 256的 mage-3特异抗体.免疫动物 CTL体外杀伤实验显示,注射基因疫苗的 Trimera小鼠脾脏淋巴细胞对靶细胞 LB373的最大杀伤率为 50%左右,而对照小鼠只有 10%以下的杀伤水平. 结论 :mage-3是一种理想的肿瘤疫苗,在人源化动物模型中能激发出特异的细胞和体液免疫,对共享 mage-3抗原的各种肿瘤细胞的临床治疗提供了实验依据.

  12. A synthetic redox biofilm made from metalloprotein-prion domain chimera nanowires

    Science.gov (United States)

    Altamura, Lucie; Horvath, Christophe; Rengaraj, Saravanan; Rongier, Anaëlle; Elouarzaki, Kamal; Gondran, Chantal; Maçon, Anthony L. B.; Vendrely, Charlotte; Bouchiat, Vincent; Fontecave, Marc; Mariolle, Denis; Rannou, Patrice; Le Goff, Alan; Duraffourg, Nicolas; Holzinger, Michael; Forge, Vincent

    2016-10-01

    Engineering bioelectronic components and set-ups that mimic natural systems is extremely challenging. Here we report the design of a protein-only redox film inspired by the architecture of bacterial electroactive biofilms. The nanowire scaffold is formed using a chimeric protein that results from the attachment of a prion domain to a rubredoxin (Rd) that acts as an electron carrier. The prion domain self-assembles into stable fibres and provides a suitable arrangement of redox metal centres in Rd to permit electron transport. This results in highly organized films, able to transport electrons over several micrometres through a network of bionanowires. We demonstrate that our bionanowires can be used as electron-transfer mediators to build a bioelectrode for the electrocatalytic oxygen reduction by laccase. This approach opens opportunities for the engineering of protein-only electron mediators (with tunable redox potentials and optimized interactions with enzymes) and applications in the field of protein-only bioelectrodes.

  13. Bactericidal effect of lactoferrin and lactoferrin chimera against halophilic Vibrio parahaemolyticus

    NARCIS (Netherlands)

    Leon-Sicairos, N.; Canizalez-Roman, A.; de la Garza, M.; Reyes-Lopez, M.; Zazueta-Beltran, J.; Nazmi, K.; Gomez-Gil, B.; Bolscher, J.G.

    2009-01-01

    Infections caused by Vibrio parahaemolyticus, an halophilic member of the genus Vibrio, have increased globally in the last 5 years. Diarrhea caused by V. parahaemolyticus results from eating raw or undercooked seafood. The aim of this work was to investigate whether lactoferrin and some lactoferrin

  14. [Sexual addiction: chimera or clinical syndrom? A plea for a clinical conceptualization].

    Science.gov (United States)

    Wölfle, Roland

    2010-01-01

    The phenomenon of sexual addiction as a clinical syndrom is discussed controversially. The article first deals with some mythological, historical and literary sources, which have been an inspiration for the nomenclature, e.g. nymphomania. Scientific research started in the 19th century, but also a classification in terms of a morally contaminated pathology, which led to barbaric forms of "therapies" and procedures, especially for women. The ICD-10 and the DSM-IV do not contain categories that correspond with the clinical experience of many experts. The application of the WHO criteria should be possible, but this might fail due to big intercultural and individual differences in defining normal sexuality as the point of origin for pathological aberrances. Later some nosological concepts and therapeutic approaches are presented. The criticism of the term of "sexual addiction" is followed by the criticism of the criticism. The article ends with the conviction, that it should be a useful and reasonable challenge for psychiatrists to come to a reliable classification of this disorder to provide easier access to serious and professional help to those who often suffer enormous pain and shame.

  15. The avian embryo as a model in developmental studies: chimeras and in vitro clonal analysis.

    Science.gov (United States)

    Dupin, E; Ziller, C; Le Douarin, N M

    1998-01-01

    The avian embryo is a model in which techniques of experimental embryology and cellular and molecular biology can converge to address fundamental questions of development biology. The first part of the chapter describes two examples of transplantation and cell labeling experiments performed in ovo. Thanks to the distinctive histologic and immunocytochemical characteristics of quail and chick cells, the migration and development of definite cells are followed in suitably constructed chimeric quail-chick embryos. Isotopic transplantations of neural tube portions between quail and chick, combined with in situ hybridization with a nucleic probe specific for a quail oligodendrocyte marker, allowed study of the origin and migration of oligodendroblasts in the spinal cord. Heterotopic transplantations of rhombomeres were performed to establish the degree of plasticity of these segments of the hindbrain regarding Hox gene expression, which was revealed by labeling with chick-specific nucleic probes. The second part describes in vitro cell cloning experiments devised to investigate cell lineage segregation and diversification during development of the NC. An original cloning procedure and optimal culture conditions permitted analysis of the developmental potentials of individual NC cells taken at definite migration stages. The results revealed a striking heterogeneity of the crest cell population, which appeared to be composed of precursors at different states of determination. Clonal cultures also provide a means to identify subsets of cells that are the target of environmental factors and to understand how extrinsic signals influence the development of responsive cells.

  16. Psychopathy Deconstructed and Reconstructed: Identifying and Assembling the Personality Building Blocks of Cleckley's Chimera.

    Science.gov (United States)

    Lilienfeld, Scott O; Watts, Ashley L; Francis Smith, Sarah; Berg, Joanna M; Latzman, Robert D

    2015-12-01

    The psychopathy field has long been beset by confusion and contention regarding the boundaries and features of this chimerical condition. We propose that this disagreement stems largely from the historical separation between psychopathy and basic personality psychology. Using findings from a meta-analysis of the correlations between the Psychopathy Checklist-Revised (PCL-R) and normal-range personality traits as a launching point, we (a) deconstruct widely used measures of psychopathy into their constituent subdimensions and (b) examine the associations of these subdimensions with higher-order and lower-order personality dimensions drawn from the Big Five and Big Three frameworks. Our review of the adult psychopathy literature reveals broad agreement that psychopathy measures are imbued with low Agreeableness and low Conscientiousness. Nevertheless, substantial disagreement revolves around the place of largely adaptive features, especially high agentic Extraversion, low Neuroticism, and high Openness, within the psychopathy construct. We propose that ongoing debates regarding the nature and boundaries of psychopathy reflect a focus on two differing operationalizations of this condition, each of which reflects a different "species" of individual.

  17. Cell culture system of a hepatitis C genotype 3a and 2a chimera

    DEFF Research Database (Denmark)

    2015-01-01

    A robust and genetically stable cell culture system for Hepatitis C Virus (HCV) genotype 3a is provided. A genotype 3a/2a (S52/JFH1) recombinant containing the structural genes (Core, E1, E2), p7 and NS2 of strain S52 was constructed and characterized in Huh7.5 cells. S52/JFH1 and J6/JFH viruses...... passaged in cell culture had comparable growth kinetics and yielded similar peak HCV RNA titers and infectivity titers. Direct genome sequencing of cell culture derived S52/JFH1 viruses identified putative adaptive mutations in Core, E2, p7, NS3, and NS5A; clonal analysis revealed that all genomes analyzed...... exhibited different combinations of these mutations. Finally, viruses resulting from transfection with RNA transcripts of five S52/JFH1 recombinants containing these combinations of putative adaptive mutations performed as efficiently as J6/JFH viruses in Huh7.5 cells and were all genetically stable after...

  18. DYNAMICS OF SOMATIC CELL-LINEAGE COMPETITION IN CHIMERAS OF Hydractinia symbiolongicarpus (CNIDARIA: HYDROZOA

    Directory of Open Access Journals (Sweden)

    RYAN S. SCHWARZ

    2007-01-01

    Full Text Available Los invertebrados coloniales y sésiles con frecuencia se fusionan con conespecíficos para formar quimeras. Estas quimeras son un ejemplo de selección natural actuando al interior del individuo en donde células genéticamente distintas compiten por acceso tanto a la línea somática como a la germinal. En este estudio se analizaron las varia- ciones temporal y espacial de linajes celulares somáticos en quimeras establecidas en el laboratorio del hidroide colonial Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa. Usando tres clones con distintas especificidades alotípicas (dos de ellas se rechazaban pero ambas se fusionaban a una tercera, se establecieron dos clases de biquimeras, una triquimera y una interacción incompatible como control. Muestras de tejido de quimeras se obtuvieron en cinco intervalos de tiempo durante 50 semanas. La identi- dad celular de cada muestra se determinó por ensayos de fusibilidad de pólipos con colonias estándar de fusibilidad conocida. Los distintos linajes celulares de cada qui- mera mostraron una habilidad competitiva diferencial, con una de ellas representando cerca del 80% de las quimeras hacia el final del estudio. Las líneas celulares con menor representación se estabilizaron a bajas frecuencias pero mantuvieron la capacidad de aumentar en frecuencia y de colonizar partes distantes en la quimera. Este compor- tamiento caracteriza los parásitos celulares. Como consecuencia de la plasticidad re- productiva de la mayoría de invertebrados coloniales, la variabilidad de los linajes celulares puede ser trasmitida a la descendencia tanto sexualmente como asexual- mente. Linajes celulares somáticos con alta capacidad competitiva serían heredados asexualmente, mientras que los linajes celulares parásitos se transmitirían preferen- cialmente por reproducción sexual.

  19. Magnetorotational dynamo chimeras. The missing link to turbulent accretion disk dynamo models?

    CERN Document Server

    Riols, A; Cossu, C; Lesur, G; Ogilvie, G I; Longaretti, P-Y

    2016-01-01

    In Keplerian accretion disks, turbulence and magnetic fields may be jointly excited through a subcritical dynamo process involving the magnetorotational instability (MRI). High-resolution simulations exhibit a tendency towards statistical self-organization of MRI dynamo turbulence into large-scale cyclic dynamics. Understanding the physical origin of these structures, and whether they can be sustained and transport angular momentum efficiently in astrophysical conditions, represents a significant theoretical challenge. The discovery of simple periodic nonlinear MRI dynamo solutions has recently proven useful in this respect, and has notably served to highlight the role of turbulent magnetic diffusion in the seeming decay of the dynamics at low magnetic Prandtl number Pm (magnetic diffusivity larger than viscosity), a common regime in accretion disks. The connection between these simple structures and the statistical organization reported in turbulent simulations remained elusive, though. Here, we report the n...

  20. Lo sport nelle scienze sociali: da chimera a realtà

    Directory of Open Access Journals (Sweden)

    Marco Pasini

    2013-04-01

    Full Text Available Lo sport per la sua trama profonda, le implicazioni che cristallizza, le emozioni che condensa, è fonte di interpretazione e osservatorio straordinariamente ricco per la ricerca sociale. L'obiettivo di questo numero della rivista, grazie ai contributi qualificati, trasversali, multidisciplinari ed empirici, è proprio quello di affrontare le questioni fondamentali sopra indicate attraverso differenti percorsi di senso e approcci teorico-metodologici specifici.

  1. Revisiting the flight of Icarus: making human organs from PSCs with large animal chimeras.

    Science.gov (United States)

    Rashid, Tamir; Kobayashi, Toshihiro; Nakauchi, Hiromitsu

    2014-10-02

    While cell therapies hold great potential for treating many conditions, their utility for treating patients that require whole organ replacement is unclear. To address this challenge, we propose using genetically engineered "organ niches" in large animals to generate human organs from pluripotent stem cells and discuss the hurdles facing such strategies.

  2. Novel GLP-1 Fusion Chimera as Potent Long Acting GLP-1 Receptor Agonist

    OpenAIRE

    Qinghua Wang; Kui Chen; Rui Liu; Fang Zhao; Sandeep Gupta; Nina Zhang; Prud'homme, Gerald J.

    2010-01-01

    GLP-1 has a variety of anti-diabetic effects. However, native GLP-1 is not suitable for therapy of diabetes due to its short half-life (t1/2168 h. Intraperitoneal glucose tolerance test (IPGTT) in mice showed that GLP-1/hIgG2 significantly decreased glucose excursion. Furthermore, IPGTT performed on mice one week after a single drug-injection also displayed significantly reduced glucose excursion, indicating that GLP-1/hIgG2 fusion protein has long-lasting effects on the modulation of glucose...

  3. Severe combined immunodeficiency mouse and human psoriatic skin chimeras. Validation of a new animal model.

    OpenAIRE

    1995-01-01

    Research into the cause and pathophysiological mechanisms underlying expression of psoriatric skin lesions has been hampered by lack of an appropriate animal model for this common and enigmatic cutaneous disease. These studies characterize normal skin, pre-psoriatic skin, and psoriatic plaque skin samples transplanted onto severe combined immunodeficiency mice. In this report we document that 1), normal, prepsoriatic, and psoriatic plaque keratome skin samples can be transplanted onto severe ...

  4. [Mutant gene expression in murine aggregation chimeras. 5. The ocular retardation and fidget genes].

    Science.gov (United States)

    Kindiakov, B N; Koniukhov, B V

    1986-01-01

    Analysis of ocular retardation (or) and fidget (fi) genes expression in 18 day old embryos, 10 and 20 day old or/or C/C----+/+ c/c and fi/fi or/or C/C----+/+ +/+ c/c mice has shown that genes or and fi are active in developing retina and suppress cell proliferation. Structural defects of retina and decrease in the eye size in the chimaeras, compared to the normal embryos, were observed already in the presence of 13-16% of mutant cells. As the fraction of mutant cells increased, the degree of eye disturbances increased as well. In the fi/fi or/or----+/+ +/+ chimaeras structural defects of retina and decrease in the eye size are more pronounced than in the or/or----+/+ chimaeras, due to the synergetical effect of both mutant genes in the fi/fi or/or cell clones. In the ontogenesis of the or/or----+/+ chimaeras the development of the retinal photoreceptor layer is normalized due to the substitution of mutant cells for actively proliferating normal cells. No metabolic cooperation between the mutant and normal cells was observed in the developing retina of chimaeras.

  5. Novel GLP-1 fusion chimera as potent long acting GLP-1 receptor agonist.

    Directory of Open Access Journals (Sweden)

    Qinghua Wang

    Full Text Available GLP-1 has a variety of anti-diabetic effects. However, native GLP-1 is not suitable for therapy of diabetes due to its short half-life (t1/2168 h. Intraperitoneal glucose tolerance test (IPGTT in mice showed that GLP-1/hIgG2 significantly decreased glucose excursion. Furthermore, IPGTT performed on mice one week after a single drug-injection also displayed significantly reduced glucose excursion, indicating that GLP-1/hIgG2 fusion protein has long-lasting effects on the modulation of glucose homeostasis. GLP-1/hIgG2 was found to be effective in reducing the incidence of diabetes in multiple-low-dose streptozotocin-induced type 1 diabetes in mice. Together, the long-lasting bioactive GLP-1/hIgG2 retains native GLP-1 activities and thus may serve as a potent GLP-1 receptor agonist.

  6. RNA/aTNA Chimeras: RNAi Effects and Nucleases Resistance of Single and Double Stranded RNAs

    Directory of Open Access Journals (Sweden)

    Adele Alagia

    2014-11-01

    Full Text Available The RNA interference pathway (RNAi is a specific and powerful biological process, triggered by small non-coding RNA molecules and involved in gene expression regulation. In this work, we explored the possibility of increasing the biological stability of these RNA molecules by replacing their natural ribose ring with an acyclic L-threoninol backbone. In particular, this modification has been incorporated at certain positions of the oligonucleotide strands and its effects on the biological properties of the siRNA have been evaluated. In vitro cellular RNAi assays have demonstrated that the L-threoninol backbone is well tolerated by the RNAi machinery in both double and single-stranded fashion, with activities significantly higher than those evinced by the unmodified RNAs and comparable to the well-known phosphorothioate modification. Additionally, this modification conferred extremely strong resistance to serum and 3′/5′-exonucleases. In view of these results, we applied this modification to the knockdown of a therapeutically relevant human gene such as apolipoprotein B (ApoB. Further studies on the activation of the innate immune system showed that L-threoninol-modified RNAs are slightly less stimulatory than unmodified RNAs.

  7. Giant viruses, giant chimeras: The multiple evolutionary histories of Mimivirus genes

    Directory of Open Access Journals (Sweden)

    Brochier-Armanet Céline

    2008-01-01

    Full Text Available Abstract Background Although capable to evolve, viruses are generally considered non-living entities because they are acellular and devoid of metabolism. However, the recent publication of the genome sequence of the Mimivirus, a giant virus that parasitises amoebas, strengthened the idea that viruses should be included in the tree of life. In fact, the first phylogenetic analyses of a few Mimivirus genes that are also present in cellular lineages suggested that it could define an independent branch in the tree of life in addition to the three domains, Bacteria, Archaea and Eucarya. Results We tested this hypothesis by carrying out detailed phylogenetic analyses for all the conserved Mimivirus genes that have homologues in cellular organisms. We found no evidence supporting Mimivirus as a new branch in the tree of life. On the contrary, our phylogenetic trees strongly suggest that Mimivirus acquired most of these genes by horizontal gene transfer (HGT either from its amoebal hosts or from bacteria that parasitise the same hosts. The detection of HGT events involving different eukaryotic donors suggests that the spectrum of hosts of Mimivirus may be larger than currently known. Conclusion The large number of genes acquired by Mimivirus from eukaryotic and bacterial sources suggests that HGT has been an important process in the evolution of its genome and the adaptation to parasitism.

  8. Applying chimera virtual data concepts to cluster finding in the Sloan Sky Survey

    Energy Technology Data Exchange (ETDEWEB)

    James Annis et al.

    2002-08-13

    The GriPhyN project is one of several major efforts working to enable large-scale data-intensive computation as a routine scientific tool. GriPhyN focuses in particular on virtual data technologies that allow computational procedures and results to be exploited as community resources so that, for example, scientists can not only run their own computations on raw data, but also discover computational procedures developed by others and data produced by these procedures. A request to retrieve data on a particular cluster might thus either lead to the retrieval of the requested data from a local or remote database or the scheduling of a computation to produce the data.

  9. At the edge of humanity: human stem cells, chimeras, and moral status.

    Science.gov (United States)

    Streiffer, Robert

    2005-12-01

    Experiments involving the transplantation of human stem cells and their derivatives into early fetal or embryonic nonhuman animals raise novel ethical issues due to their possible implications for enhancing the moral status of che chimeric individual. Although status-enhancing research is not necessarily objectionable from the perspective of the chimeric individual, there are grounds for objecting to it in the conditions in which it is likely to occur. Translating this ethical conclusion into a policy recommendation, however, is complicated by the fact that substantial empirical and ethical uncertainties remain about which transplants, if any, would significantly enhance the chimeric individual's moral status. Considerations of moral status justify either an early-termination policy on chimeric embryos, or, in the absence of such a policy, restrictions on the introduction of pluripotent human stem cells into early-stage developing animals, pending the resolution of those uncertainties.

  10. From naïve pluripotency to chimeras: a new ethical challenge?

    Science.gov (United States)

    Hyun, Insoo

    2015-01-01

    In recent years, there has been much interest in the prospect of generating and using human stem cells that exhibit a state of naïve pluripotency. Such a pluripotent state might be functionally confirmed by assessing the chimeric contribution of these cells to non-human blastocysts. Furthermore, the generation of naïve human pluripotent stem cells in vitro could lead to the creation of chimeric animal models that can facilitate the study of human development and disease. However, these lines of research raise thorny ethical concerns about the moral status of such chimeric animals. Here, I call attention to these ethical barbs and suggest a way in which to proceed cautiously.

  11. The HFEA public consultation process on hybrids and chimeras: informed, effective, and meaningful?

    Science.gov (United States)

    Baylis, Françoise

    2009-03-01

    In September 2007, the Human Fertilisation and Embryology Authority (HFEA) in the United Kingdom concluded that "there is no fundamental reason to prevent cytoplasmic hybrid research ... this area of research can, with caution and careful scrutiny, be permitted." Later, in January 2008, HFEA issued two research licenses to create humanesque cytoplasmic hybrid embryos from which stem cells could be derived. This article critically examines the public consultation process that preceded these decisions, concluding that the process was flawed and demonstrating how the HFEA documents summarizing the findings of the public consultation process misrepresent the public's contributions to this policymaking initiative.

  12. [Residual neurovirulence of the chimera of Langat and Denge-4 flaviviruses in intracerebral infection of monkeys].

    Science.gov (United States)

    Karganova, G G; Pripuzova, N S; Tereshkina, N V; Gmyl', L V; Dzhivanian, T I; Rumiantsev, A A; Lashkevich, V A

    2005-01-01

    The residual neurovirulence of the previously obtained chimeric virus Tp21/DEN4, containing the RNA region encoding the pre M and E structural enzymes, strain Tp21, virus Langat, and the remaining part of the genome from the Denge 4 virus, was studied in experiments with monkeys Cercopithecus aethiops involving the intracerebral administration of the virus. The tick-borne encephalitis virus, strain Absettarov, was used as positive control. A comparative analysis of the experimental and published data showed the chimeric virus to be less virulent by its degree of morphological affection in the CNS zones, its spread into the CNS and by a percentage share of animals with viremia versus the Tp21 parent strain and Elantsev strain of the Langat virus.

  13. Responses to recipient and donor B cells by genetically donor T cells from human haploidentical chimeras

    Energy Technology Data Exchange (ETDEWEB)

    Schiff, S.; Sampson, H.; Buckley, R.

    1986-03-01

    Following administration of haploidentical stem cells to infants with severe combined immunodeficiency (SCID), mature T cells of donor karyotype appear later in the recipient without causing graft-versus-host disease. To investigate the effect of the host environment on the responsiveness of these genetically donor T cells, blood B and T lymphocytes from 6 SCID recipients, their parental donors and unrelated controls were purified by double SRBC rosetting. T cells were stimulated by irradiated B cells at a 1:1 ratio in 6 day cultures. Engrafted T cells of donor karyotype gave much smaller responses to irradiated genetically recipient B cells than did fresh donor T cells. Moreover, engrafted T cells of donor karyotype from two of the three SCIDs who are longest post-transplantation responded more vigorously (14,685 and 31,623 cpm) than fresh donor T cells (5141 and 22,709 cpm) to donor B cells. These data indicate that T lymphocytes which have matured from donor stem cells in the recipient microenvironment behave differently from those that have matured in the donor.

  14. Assessing species-specific contributions to craniofacial development using quail-duck chimeras.

    Science.gov (United States)

    Fish, Jennifer L; Schneider, Richard A

    2014-05-31

    The generation of chimeric embryos is a widespread and powerful approach to study cell fates, tissue interactions, and species-specific contributions to the histological and morphological development of vertebrate embryos. In particular, the use of chimeric embryos has established the importance of neural crest in directing the species-specific morphology of the craniofacial complex. The method described herein utilizes two avian species, duck and quail, with remarkably different craniofacial morphology. This method greatly facilitates the investigation of molecular and cellular regulation of species-specific pattern in the craniofacial complex. Experiments in quail and duck chimeric embryos have already revealed neural crest-mediated tissue interactions and cell-autonomous behaviors that regulate species-specific pattern in the craniofacial skeleton, musculature, and integument. The great diversity of neural crest derivatives suggests significant potential for future applications of the quail-duck chimeric system to understanding vertebrate development, disease, and evolution.

  15. Patterns of Amino Acid Evolution in the Drosophila ananassae Chimeric Gene, siren, Parallel Those of Other Adh-Derived Chimeras

    Science.gov (United States)

    Shih, Hung-Jui; Jones, Corbin D.

    2008-01-01

    siren1 and siren2 are novel alcohol dehydrogenase (Adh)-derived chimeric genes in the Drosophila bipectinata complex. D. ananassae, however, harbors a single homolog of these genes. Like other Adh-derived chimeric genes, siren evolved adaptively shortly after it was formed. These changes likely shifted the catalytic activity of siren. PMID:18780749

  16. Complement factor 5a receptor chimeras reveal the importance of lipid-facing residues in transport competence

    DEFF Research Database (Denmark)

    Klco, Jeffery M; Sen, Saurabh; Hansen, Jakob L

    2009-01-01

    was exchanged with the cognate residues from the angiotensin type 1 receptor. Disulfide-trapping and bioluminescence resonance energy transfer (BRET) studies demonstrated robust homodimerization of both complement factor 5a receptor and angiotensin type 1 receptor, but no evidence for heterodimerization...

  17. In silico vaccine design based on molecular simulations of rhinovirus chimeras presenting HIV-1 gp41 epitopes.

    Science.gov (United States)

    Lapelosa, Mauro; Gallicchio, Emilio; Arnold, Gail Ferstandig; Arnold, Eddy; Levy, Ronald M

    2009-01-16

    A cluster of promising epitopes for the development of human immunodeficiency virus (HIV) vaccines is located in the membrane-proximal external region (MPER) of the gp41 subunit of the HIV envelope spike structure. The crystal structure of the peptide corresponding to the so-called ELDKWA epitope (HIV-1 HxB2 gp41 residues 662-668), in complex with the corresponding broadly neutralizing human monoclonal antibody 2F5, provides a target for structure-based vaccine design strategies aimed at finding macromolecular carriers that are able to present this MPER-derived epitope with optimal antigenic activity. To this end, a series of replica exchange molecular dynamics computer simulations was conducted to characterize the distributions of conformations of ELDKWA-based epitopes inserted into a rhinovirus carrier and to identify those with the highest fraction of conformations that are able to bind 2F5. The length, hydrophobic character, and precise site of insertion were found to be critical for achieving structural similarity to the target crystal structure. A construct with a high degree of complementarity to the corresponding determinant region of 2F5 was obtained. This construct was employed to build a high-resolution structural model of the complex between the 2F5 antibody and the chimeric human rhinovirus type 14:HIV-1 ELDKWA virus particle. Additional simulations, which were conducted to study the conformational propensities of the ELDKWA region in solution, confirm the hypothesis that the ELDKWA region of gp41 is highly flexible and capable of assuming helical conformations (as in the postfusion helical bundle structure) and beta-turn conformations (as in the complex with the 2F5 antibody). These results also suggest that the ELDKWA epitope can be involved in intramolecular--and likely intermolecular--hydrophobic interactions. This tendency offers an explanation for the observation that mutations decreasing the hydrophobic character of the MPER in many cases result in conformational changes that increase the affinity of this region for the 2F5 antibody.

  18. Cytoplasmic localization of a functionally active Fanconi anemia group A green fluorescent protein chimera in human 293 cells

    NARCIS (Netherlands)

    Kruyt, FAE; Waisfisz, Q; Dijkmans, LM; Hermsen, M.A.; Youssoufian, H; Arwert, F; Joenje, H

    1997-01-01

    Hypersensitivity to cross-linking agents and predisposition to malignancy are characteristic of the genetically heterogeneous inherited bone marrow failure syndrome, Fanconi anemia (FA). The protein encoded by the recently cloned FA complementation group A gene, FAA, has been expected to localize in

  19. Micelle PCR reduces chimera formation in 16S rRNA profiling of complex microbial DNA mixtures

    NARCIS (Netherlands)

    S.A. Boers (Stefan A.); J.P. Hays (John P.); R. Jansen (Ruud)

    2015-01-01

    textabstract16S rRNA gene profiling has revolutionized the field of microbial ecology. Many researchers in various fields have embraced this technology to investigate bacterial compositions of samples derived from many different ecosystems. However, it is important to acknowledge the current limitat

  20. Construction and characterization of infectious hepatitis C virus chimera containing structural proteins directly from genotype 1b clinical isolates.

    Science.gov (United States)

    Lu, Jie; Tao, Wanyin; Li, Rui; Xiang, Yu; Zhang, Nan; Xiang, Xiaogang; Xie, Qing; Zhong, Jin

    2013-08-15

    HCV genotype is a major determinant of clinical outcome, and GT1b HCV infection is the most difficult to treat and also the predominant genotype in East Asia and Europe. We developed 1b/JFH-1 inter-genotypic recombinants containing the structural genes (Core, E1, E2), p7 and the 1stTMD of NS2 directly from GT1b clinical isolates. Through a cloning selection strategy, we obtained 4 functional clones from 3 cases of GT1b patients' sera, which could produce infectious viruses in Huh7.5.1 cells. Sequencing analysis of recovered viruses from serial passage and reverse genetics revealed that adaptive mutations in the GT1b-originated region were enough for the enhancement of infectivity. A monoclonal antibody to E2 and original patient sera could efficiently block 3 of the viruses (26C3mt, 52B6mt and 79L9) while had little effect on 26C6mt viruses. The availability of 1b/JFH-1 chimeric viruses will be important for studies of isolate-specific neutralization and useful in evaluating antiviral therapies.

  1. HPV-18 E2circumflexE4 chimera: 2 new spliced transcripts and proteins induced by keratinocyte differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Chye Ling [Papillomavirus Regulation and Cancer, Institute of Medical Biology, Agency for Science, Technology and Research (A-STAR), Biopolis, 8A Biomedical Grove, Immunos, Singapore 138648 (Singapore); Gunaratne, Jayantha [Mass Spectrometry and Systems Biology Laboratory, Institute of Molecular and Cell Biology, A-STAR, Biopolis, 61 Biopolis Drive, Proteos, Singapore 138673 (Singapore); Lai, Deborah [Papillomavirus Regulation and Cancer, Institute of Medical Biology, Agency for Science, Technology and Research (A-STAR), Biopolis, 8A Biomedical Grove, Immunos, Singapore 138648 (Singapore); Carthagena, Laetitia [UMR-S996, Universite Paris-Sud 11, 32 rue des Carnets, 92140 Clamart (France); Wang, Qian [MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London N10 3UE (United Kingdom); Xue, Yue Zhen; Quek, Ling Shih [Papillomavirus Regulation and Cancer, Institute of Medical Biology, Agency for Science, Technology and Research (A-STAR), Biopolis, 8A Biomedical Grove, Immunos, Singapore 138648 (Singapore); Doorbar, John [MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London N10 3UE (United Kingdom); Bachelerie, Francoise [UMR-S996, Universite Paris-Sud 11, 32 rue des Carnets, 92140 Clamart (France); Thierry, Francoise, E-mail: francoise.thierry@imb.a-star.edu.sg [Papillomavirus Regulation and Cancer, Institute of Medical Biology, Agency for Science, Technology and Research (A-STAR), Biopolis, 8A Biomedical Grove, Immunos, Singapore 138648 (Singapore); Bellanger, Sophie, E-mail: sophie.bellanger@imb.a-star.edu.sg [Papillomavirus Regulation and Cancer, Institute of Medical Biology, Agency for Science, Technology and Research (A-STAR), Biopolis, 8A Biomedical Grove, Immunos, Singapore 138648 (Singapore)

    2012-07-20

    The Human Papillomavirus (HPV) E4 is known to be synthesized as an E1circumflexE4 fusion resulting from splice donor and acceptor sites conserved across HPV types. Here we demonstrate the existence of 2 HPV-18 E2circumflexE4 transcripts resulting from 2 splice donor sites in the 5 Prime part of E2, while the splice acceptor site is the one used for E1circumflexE4. Both E2circumflexE4 transcripts are up-regulated by keratinocyte differentiation in vitro and can be detected in clinical samples containing low-grade HPV-18-positive cells from Pap smears. They give rise to two fusion proteins in vitro, E2circumflexE4-S and E2circumflexE4-L. Whereas we could not differentiate E2circumflexE4-S from E1circumflexE4 in vivo, E2circumflexE4-L could be formally identified as a 23 kDa protein in raft cultures in which the corresponding transcript was also found, and in a biopsy from a patient with cervical intraepithelial neoplasia stage I-II (CINI-II) associated with HPV-18, demonstrating the physiological relevance of E2circumflexE4 products.

  2. RNA-DNA Chimeras in the Context of an RNA World Transition to an RNA/DNA World.

    Science.gov (United States)

    Gavette, Jesse V; Stoop, Matthias; Hud, Nicholas V; Krishnamurthy, Ramanarayanan

    2016-10-10

    The RNA world hypothesis posits that DNA and proteins were later inventions of early life, or the chemistry that gave rise to life. Most scenarios put forth for the emergence of DNA assume a clean separation of RNA and DNA polymer, and a smooth transition between RNA and DNA. However, based on the reality of "clutter" and lack of sophisticated separation/discrimination mechanisms in a protobiological (and/or prebiological) world, heterogeneous RNA-DNA backbone containing chimeric sequences could have been common-and have not been fully considered in models transitioning from an RNA world to an RNA-DNA world. Herein we show that there is a significant decrease in Watson-Crick duplex stability of the heterogeneous backbone chimeric duplexes that would impede base-pair mediated interactions (and functions). These results point to the difficulties for the transition from one homogeneous system (RNA) to another (RNA/DNA) in an RNA world with a heterogeneous mixture of ribo- and deoxyribonucleotides and sequences, while suggesting an alternative scenario of prebiological accumulation and co-evolution of homogeneous systems (RNA and DNA).

  3. A Salmonella Typhimurium-Typhi genomic chimera: a model to study Vi polysaccharide capsule function in vivo.

    Directory of Open Access Journals (Sweden)

    Angela M Jansen

    2011-07-01

    Full Text Available The Vi capsular polysaccharide is a virulence-associated factor expressed by Salmonella enterica serotype Typhi but absent from virtually all other Salmonella serotypes. In order to study this determinant in vivo, we characterised a Vi-positive S. Typhimurium (C5.507 Vi(+, harbouring the Salmonella pathogenicity island (SPI-7, which encodes the Vi locus. S. Typhimurium C5.507 Vi(+ colonised and persisted in mice at similar levels compared to the parent strain, S. Typhimurium C5. However, the innate immune response to infection with C5.507 Vi(+ and SGB1, an isogenic derivative not expressing Vi, differed markedly. Infection with C5.507 Vi(+ resulted in a significant reduction in cellular trafficking of innate immune cells, including PMN and NK cells, compared to SGB1 Vi(- infected animals. C5.507 Vi(+ infection stimulated reduced numbers of TNF-α, MIP-2 and perforin producing cells compared to SGB1 Vi(-. The modulating effect associated with Vi was not observed in MyD88(-/- and was reduced in TLR4(-/- mice. The presence of the Vi capsule also correlated with induction of the anti-inflammatory cytokine IL-10 in vivo, a factor that impacted on chemotaxis and the activation of immune cells in vitro.

  4. "A Chimera of Sorts": Rethinking Educational Technology Grant Programs, Courseware Innovation, and the Language of Educational Change

    Science.gov (United States)

    Wolff, William I.

    2008-01-01

    How do we know when an educational organization, process, or courseware tool is "innovative"? How do we define the processes that encourage change or the ways in which faculty "develop" new courseware "innovations"? The terms "innovation", "change", and "development" have been overused in so many contexts that they now seem to have lost their…

  5. A GTPase chimera illustrates an uncoupled nucleotide affinity and release rate, Providing insight into the activation mechanism

    DEFF Research Database (Denmark)

    Guilfoyle, Amy P.; Deshpande, Chandrika N.; Font Sadurni, Josep;

    2014-01-01

    The release of GDP from GTPases signals the initiation of a GTPase cycle, where the association of GTP triggers conformational changes promoting binding of downstream effector molecules. Studies have implicated the nucleotide-binding G5 loop to be involved in the GDP release mechanism. For example......, biophysical studies on both the eukaryotic Gα proteins and the GTPase domain (NFeoB) of prokaryotic FeoB proteins have revealed conformational changes in the G5 loop that accompany nucleotide binding and release. However, it is unclear whether this conformational change in the G5 loop is a prerequisite...... GTPase activity at a similar level to wild-type NFeoB, and structural analyses of the nucleotide-free and GDP-bound proteins show that the G5 loop adopts conformations analogous to that of the human nucleotide-bound Giα1 protein in both states. Interestingly, isothermal titration calorimetry and stopped...

  6. miRNA-target chimeras reveal miRNA 3'-end pairing as a major determinant of Argonaute target specificity

    DEFF Research Database (Denmark)

    Moore, Michael J; Scheel, Troels K H; Luna, Joseph M;

    2015-01-01

    AGO HITS-CLIP strategy termed CLEAR (covalent ligation of endogenous Argonaute-bound RNAs)-CLIP, which enriches miRNAs ligated to their endogenous mRNA targets. CLEAR-CLIP mapped ∼130,000 endogenous miRNA-target interactions in mouse brain and ∼40,000 in human hepatoma cells. Motif and structural...

  7. Specific tolerance induction across a xenogeneic barrier: production of mixed rat/mouse lymphohematopoietic chimeras using a nonlethal preparative regimen

    OpenAIRE

    1990-01-01

    The development of safe methods for inducing donor-specific tolerance across xenogeneic barriers could potentially relieve the critical shortage of allograft donors that currently limits the applicability of organ transplantation. We report here that such tolerance can be induced in a xenogeneic combination (rat----mouse) using a nonmyeloablative and nonlethal preparative regimen. Successful induction of chimerism and donor-specific transplantation tolerance required pretreatment of recipient...

  8. Primary Cerebellar Neuroendocrine Tumors: Chimeras or Real Entities? A Case Report with a 6-Year Follow-Up

    Directory of Open Access Journals (Sweden)

    Claudio Vernieri

    2016-08-01

    Full Text Available We report the case of a 38-year-old patient who was diagnosed with a cerebellar well-differentiated neuroendocrine tumor (WDNET in 2009. At first glance, we believed that it was a metastasis from an unrecognized WDNET arising outside the cerebellum. However, despite a prolonged follow-up of 6 years, an extracranial WDNET has never been found. During this time, the tumor recurred locally twice, and the patient was treated with surgery and radiotherapy. At the moment, he enjoys good general conditions and his tumor is under control. Due to the histopathological characteristics and clinical behavior of the tumor, we believe that this is the first report to date of a primary cerebellar WDNET.

  9. Primary Cerebellar Neuroendocrine Tumors: Chimeras or Real Entities? A Case Report with a 6-Year Follow-Up.

    Science.gov (United States)

    Vernieri, Claudio; Femia, Daniela; Pusceddu, Sara; Capella, Carlo; Rosai, Juan; Calareso, Giuseppina; Concas, Laura; Prinzi, Natalie; Lo Russo, Giuseppe; de Braud, Filippo; Buzzoni, Roberto

    2016-01-01

    We report the case of a 38-year-old patient who was diagnosed with a cerebellar well-differentiated neuroendocrine tumor (WDNET) in 2009. At first glance, we believed that it was a metastasis from an unrecognized WDNET arising outside the cerebellum. However, despite a prolonged follow-up of 6 years, an extracranial WDNET has never been found. During this time, the tumor recurred locally twice, and the patient was treated with surgery and radiotherapy. At the moment, he enjoys good general conditions and his tumor is under control. Due to the histopathological characteristics and clinical behavior of the tumor, we believe that this is the first report to date of a primary cerebellar WDNET.

  10. Identification of residues involved in binding of IL5 to betacom using betaIL3 and betacom chimeras.

    Science.gov (United States)

    Czabotar, P E; Holland, J; Sanderson, C J

    1999-10-22

    In mice there are two forms of the beta chain used in the IL3 receptor system, betacom and betaIL3. betacom is used by the IL3, IL5 and GM-CSF receptors whereas betaIL3 is only used in the IL3 receptor. In this work an assay was developed to identify residues of beta1L3 that restrict IL5 activity. It was found that such residues reside within the 2nd CRM of the molecule. Furthermore, when residues in the betaIL3 B'-C' loop were replaced with betacom sequence a form of betaIL3 was produced that was able to respond to IL5. This region is also responsible for IL3 binding to betaIL3 in the absence of alpha chain. It is therefore an important structural motif of betacom and betaIL3 responsible for both ligand interaction and specificity.

  11. Detection of antigens using a protein-DNA chimera developed by enzymatic covalent bonding with phiX gene A*.

    Science.gov (United States)

    Akter, Farhima; Mie, Masayasu; Grimm, Sebastian; Nygren, Per-Åke; Kobatake, Eiry

    2012-06-01

    The chemical reactions used to make antibody-DNA conjugates in many immunoassays diminish antigen-binding activity and yield heterogeneous products. Here, we address these issues by developing an antibody-based rolling circle amplification (RCA) strategy using a fusion of φX174 gene A* protein and Z(mab25) (A*-Zmab). The φX174 gene A* protein is an enzyme that can covalently link with DNA, while the Z(mab25) protein moiety can bind to specific species of antibodies. The DNA in an A*-Zmab conjugate was attached to the A* protein at a site chosen to not interfere with protein function, as determined by enzyme-linked immunosorbent assay (ELISA) and gel mobility shift analysis. The novel A*-Zmab-DNA conjugate retained its binding capabilities to a specific class of murine immunoglobulin γ1 (IgG1) but not to rabbit IgG. This indicates the generality of the A*-Zmab-based immuno-RCA assay that can be used in-sandwich ELISA format. Moreover, the enzymatic covalent method dramatically increased the yields of A*-Zmab-DNA conjugates up to 80% after a 15 min reaction. Finally, sensitive detection of human interferon-γ (IFN-γ) was achieved by immuno-RCA using our fusion protein in sandwich ELISA format. This new approach of the use of site-specific enzymatic DNA conjugation to proteins should be applicable to fabrication of novel immunoassays for biosensing.

  12. Differences in chimera formation and germline transmission between E14 and C2J embryonic stem cells in mice.

    Science.gov (United States)

    Zhu, Yan; Li, Dun-Gao; Sun, Zhao-Gui; Chen, Xue-Jin; Jiang, Man-Xi

    2014-05-01

    Summary The goal of this project was to determine whether the originating strain of mouse embryonic stem (ES) cells affects the maintenance of their pluripotency under uniform culture conditions. ES cells from two strains of mice, E14 and C2J, were tested. Both ES cell lines were cultured in KOSR + 2i medium and then injected into C57BL/6J blastocysts. Our results demonstrate that this medium could support both E14 and C2J ES cells to keep their pluripotency, though E14 ES cells were found to have a higher chimeric rate than C2J ES cells. However, analysis by backcrossing revealed that C2J and E14 ES cells have the same ability for germline transmission. Our results demonstrate that ES cells derived from E14 and C2J cells have the same capacity for germline transmission when injected into C57BL/6J blastocysts; however, due to the limitation of mixed genetic background between E14 cells and host C57BL/6J embryos, C2J ES cells are preferable to E14 ES cells for use in gene-targeting and should become the cell line of choice for the generation of genetically engineered mutant mouse lines.

  13. Network-Centric Operations -- Promise, Chimera, and Achilles’ Heel: Challenges and Pitfalls for Networks and Information Infrastructure

    Science.gov (United States)

    2005-04-01

    104 9 Ibid. pages 135-150 10 Ibid. pages 149-150 and Andre Broido, "Visualizing Internet Topology at a Macroscopic Scale," ( CAIDA Topology Mapping...Worm," ( CAIDA at http://www.caida.org/outreach/papers/2003/sapphire/sapphire.html, 2003), Colleen Shannon, "The Spread of the Witty Worm," ( CAIDA at...ADF capabilities through Network Enabled Operations 2003. Broido, Andre. "Visualizing Internet Topology at a Macroscopic Scale." CAIDA Topology

  14. Bactericidal effect of bovine lactoferrin and synthetic peptide lactoferrin chimera in Streptococcus pneumoniae and the decrease in luxS gene expression by lactoferrin

    NARCIS (Netherlands)

    N. León-Sicairos; U.A. Angulo-Zamudio; J.E. Vidal; C.A. López-Torres; J.G.M. Bolscher; K. Nazmi; R. Reyes-Cortes; M. Reyes-López; M. de la Garza; A. Canizalez-Román

    2014-01-01

    Streptococcus pneumoniae (pneumococcus) is responsible for nearly one million child deaths annually. Pneumococcus causes infections such as pneumonia, otitis media, meningitis, and sepsis. The human immune system includes antibacterial peptides and proteins such as lactoferrin (LF), but its activity

  15. Polypyrimidine tract binding protein-1 (PTB1) is a determinant of the tissue and host tropism of a human rhinovirus/poliovirus chimera PV1(RIPO).

    Science.gov (United States)

    Jahan, Nusrat; Wimmer, Eckard; Mueller, Steffen

    2013-01-01

    The internal ribosomal entry site (IRES) of picornavirus genomes serves as the nucleation site of a highly structured ribonucleoprotein complex essential to the binding of the 40S ribosomal subunit and initiation of viral protein translation. The transition from naked RNA to a functional "IRESome" complex are poorly understood, involving the folding of secondary and tertiary RNA structure, facilitated by a tightly concerted binding of various host cell proteins that are commonly referred to as IRES trans-acting factors (ITAFs). Here we have investigated the influence of one ITAF, the polypyrimidine tract-binding protein 1 (PTB1), on the tropism of PV1(RIPO), a chimeric poliovirus in which translation of the poliovirus polyprotein is under the control of a human rhinovirus type 2 (HRV2) IRES element. We show that PV1(RIPO)'s growth defect in restrictive mouse cells is partly due to the inability of its IRES to interact with endogenous murine PTB. Over-expression of human PTB1 stimulated the HRV2 IRES-mediated translation, resulting in increased growth of PV1(RIPO) in murine cells and human neuronal SK-N-MC cells. Mutations within the PV1(RIPO) IRES, selected to grow in restrictive mouse cells, eliminated the human PTB1 supplementation requirement, by restoring the ability of the IRES to interact with endogenous murine PTB. In combination with our previous findings these results give a compelling insight into the thermodynamic behavior of IRES structures. We have uncovered three distinct thermodynamic aspects of IRES formation which may independently contribute to overcome the observed PV1(RIPO) IRES block by lowering the free energy δG of the IRESome formation, and stabilizing the correct and functional structure: 1) lowering the growth temperature, 2) modifying the complement of ITAFs in restricted cells, or 3) selection of adaptive mutations. All three mechanisms can conceivably modulate the thermodynamics of RNA folding, and thus facilitate and stabilize the functional IRES structure.

  16. Polypyrimidine tract binding protein-1 (PTB1 is a determinant of the tissue and host tropism of a human rhinovirus/poliovirus chimera PV1(RIPO.

    Directory of Open Access Journals (Sweden)

    Nusrat Jahan

    Full Text Available The internal ribosomal entry site (IRES of picornavirus genomes serves as the nucleation site of a highly structured ribonucleoprotein complex essential to the binding of the 40S ribosomal subunit and initiation of viral protein translation. The transition from naked RNA to a functional "IRESome" complex are poorly understood, involving the folding of secondary and tertiary RNA structure, facilitated by a tightly concerted binding of various host cell proteins that are commonly referred to as IRES trans-acting factors (ITAFs. Here we have investigated the influence of one ITAF, the polypyrimidine tract-binding protein 1 (PTB1, on the tropism of PV1(RIPO, a chimeric poliovirus in which translation of the poliovirus polyprotein is under the control of a human rhinovirus type 2 (HRV2 IRES element. We show that PV1(RIPO's growth defect in restrictive mouse cells is partly due to the inability of its IRES to interact with endogenous murine PTB. Over-expression of human PTB1 stimulated the HRV2 IRES-mediated translation, resulting in increased growth of PV1(RIPO in murine cells and human neuronal SK-N-MC cells. Mutations within the PV1(RIPO IRES, selected to grow in restrictive mouse cells, eliminated the human PTB1 supplementation requirement, by restoring the ability of the IRES to interact with endogenous murine PTB. In combination with our previous findings these results give a compelling insight into the thermodynamic behavior of IRES structures. We have uncovered three distinct thermodynamic aspects of IRES formation which may independently contribute to overcome the observed PV1(RIPO IRES block by lowering the free energy δG of the IRESome formation, and stabilizing the correct and functional structure: 1 lowering the growth temperature, 2 modifying the complement of ITAFs in restricted cells, or 3 selection of adaptive mutations. All three mechanisms can conceivably modulate the thermodynamics of RNA folding, and thus facilitate and stabilize the functional IRES structure.

  17. 小鼠胚胎干细胞与四倍体胚胎的嵌合%Chimera of mouse ES cells and tetraploid embryos

    Institute of Scientific and Technical Information of China (English)

    李相运; 窦忠英; 李松

    2003-01-01

    The oviducts of superovulated Kunming white females were flushed 44-46 hours after treatment with human chorionic gonadotropin to collect 1074 late two-cell-stage embryos.The embryos were placed twenty at a time between two platinum electrodes laid 1 mm apart in 0.3M mannitol in the electrode chamber.The blastomeres were fused by a short electric pulse(80V for 50μsec) applied by a pulse generator.Fusion of blastomeres was usually completed in 20-60minutes.After 25 hours of culture,most of the tetraploid embryos developed to the four-cell stage.Zonae pellucidae of 387 four-cell-stage tetraploid embryos were removed by treatment with acid Tyrode's buffer.The embryos were plated on an ES cell layer,After 40 hours of coculture,248 embryos aggregated with ES cells were collected and transferred into the uteri of twenty four 2.5-day pseudopregnant recipinets.Ten recipients were pregnant.but no live fetuses were born.Three pregnant recipients were routinely subject to a Caesarean section on day 18 of pregnancy and seven abnormal fetuses were obtained.The results demonstrate that ES cells derived from C57BL/6 mice are pluripotential to a certain extent.

  18. Complete sequence of the first chimera genome constructed by cloning the whole genome of Synechocystis strain PCC6803 into the Bacillus subtilis 168 genome.

    Science.gov (United States)

    Watanabe, Satoru; Shiwa, Yuh; Itaya, Mitsuhiro; Yoshikawa, Hirofumi

    2012-12-01

    Genome synthesis of existing or designed genomes is made feasible by the first successful cloning of a cyanobacterium, Synechocystis PCC6803, in Gram-positive, endospore-forming Bacillus subtilis. Whole-genome sequence analysis of the isolate and parental B. subtilis strains provides clues for identifying single nucleotide polymorphisms (SNPs) in the 2 complete bacterial genomes in one cell.

  19. Sensitive and specific detection of miRNA using an isothermal exponential amplification method using fluorescence-labeled LNA/DNA chimera primers.

    Science.gov (United States)

    Huang, Jun-Fu; Zhao, Na; Xu, Han-Qing; Xia, Han; Wei, Kun; Fu, Wei-Ling; Huang, Qing

    2016-10-01

    MicroRNAs (miRNAs) are currently considered as potential biomarkers for various human diseases. In the present study, miRNA-triggered real-time fluorescent isothermal reaction with exponential amplification (ReFIRE) with or without Thermus aquaticus MutS (Taq MutS) was developed to analyze miRNAs using DNA polymerase, a nicking endonuclease, and fluorescently labeled primers. In the absence of Taq MutS, the ReFIRE system permitted the detection of 100 ymol of targeted miRNA in 80 min. However, this system enabled limited differentiation between homologous miRNA family members. Upon addition of Taq MutS to the ReFIRE system, non-specific amplification generated from the mishybridization between primers and primer dimers or primers and the template duplex was eliminated. The addition of Taq MutS enabled the ultrasensitive detection of as little as 10 ymol of targeted miRNAs in 50 min, which corresponds to less than 10 copies of miRNAs in a total volume of 20 μl. Additionally, the assay exhibited a dynamic range of up to 12 orders of magnitude. The ReFIRE system also showed high specificity, enabling differentiation between homologous miRNA family members exhibiting only single-base differences. The sensitivity, specificity, and dynamic range associated with this system were greater than most currently available miRNA isothermal amplification assays. Moreover, when target-specific primers were labeled with different fluorescent reporters, multiplex analysis was easily performed in a single tube, permitting accurate normalization of miRNA expression. This simple, fast, ultrasensitive, highly specific, and easy-to-multiplex method could significantly contribute to research investigations pertaining to the biological roles of miRNA, as well as clinical diagnosis of various diseases that involve miRNA disruptions. Graphical Abstract The principle of ReFIRE system.

  20. Acquired immunologic tolerance in chimeras and histocompatibility factors in cattle and their relationship to those in humans. Final report. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Stone, W.H.

    1976-03-01

    During the course of this project we have studied 35 pairs of chimeric cattle twins. It is now clear that fractionated doses of whole-body /sup 60/Co irradiation can cause marked shifts in the proportions of the two erythrocyte populations that make up the chimeric mixture. However, it has not been possible to eliminate one of the two cell types and thus abrogate the acquired immunologic tolerance. The results of our extensive skin-grafting experiments are remarkable because they show that a chimeric twin may mount a sufficient immune response to reject its cotwin's skin while remaining completely tolerant to erythropoietic elements of its cotwin. In conjunction with these studies, we have acquired sufficient data to define a major histocompatibility locus in cattle using alloimmune anti-lymphocyte typing sera as well as the mixed lymphocyte culture technic. This project has also yielded a considerable number of new immunogenetic parameters for cattle, monkeys and birds. Such parameters are useful for basic and applied studies in immunology.

  1. Pharmacological characterisation of α6β4* nicotinic acetylcholine receptors assembled from three different α6/α3 subunit chimeras in tsA201 cells

    DEFF Research Database (Denmark)

    Jensen, Anne Bjørnskov; Hoestgaard-Jensen, Kirsten; Jensen, Anders A.

    2014-01-01

    . In the FLIPR™ Membrane Potential Blue assay, the agonists exhibited the same rank order of potencies [(±)-epibatidine>sazetidine A>varenicline>(−)-cytisine~(S)-nicotine>acetylcholine>carbachol] at the C1β4, C1β4β3, C6F223Lβ4, C6F223Lβ4β3, C16F223Lβ4 and C16F223Lβ4β3 receptors, albeit the absolute EC50 values...

  2. Engineered DsbC chimeras catalyze both protein oxidation and disulfide-bond isomerization in Escherichia coli: Reconciling two competing pathways

    OpenAIRE

    Segatori, Laura; Paukstelis, Paul J.; Gilbert, Hiram F.; Georgiou, George

    2004-01-01

    In the Escherichia coli periplasm, the formation of protein disulfide bonds is catalyzed by DsbA and DsbC. DsbA is a monomer that is maintained in a fully oxidized state by the membrane enzyme DsbB, whereas DsbC is a dimer that is kept reduced by a second membrane protein, DsbD. Although the catalytic regions of DsbA and DsbC are composed of structurally homologous thioredoxin motif domains, DsbA serves only as an oxidase in vivo, whereas DsbC catalyzes disulfide reduction and isomerization a...

  3. Microbicidal effect of the lactoferrin peptides Lactoferricin17-30, Lactoferrampin265-284, and Lactoferrin chimera on the parasite Entamoeba histolytica

    NARCIS (Netherlands)

    López-Soto, F.; León-Sicairos, N.; Nazmi, K.; Bolscher, J.G.; de la Garza, M.

    2010-01-01

    Entamoeba histolytica is a parasitic protozoan that produces amoebiasis, an intestinal disease characterized by ulcerative colitis and dysentery. In some cases, trophozoites can travel to the liver leading to hepatic abscesses and death. Recently, lactoferrin and lactoferricin B have been shown to b

  4. A HIV-Tat/C4-binding protein chimera encoded by a DNA vaccine is highly immunogenic and contains acute EcoHIV infection in mice

    Science.gov (United States)

    Tomusange, Khamis; Wijesundara, Danushka; Gummow, Jason; Garrod, Tamsin; Li, Yanrui; Gray, Lachlan; Churchill, Melissa; Grubor-Bauk, Branka; Gowans, Eric J.

    2016-01-01

    DNA vaccines are cost-effective to manufacture on a global scale and Tat-based DNA vaccines have yielded protective outcomes in preclinical and clinical models of human immunodeficiency virus (HIV), highlighting the potential of such vaccines. However, Tat-based DNA vaccines have been poorly immunogenic, and despite the administration of multiple doses and/or the addition of adjuvants, these vaccines are not in general use. In this study, we improved Tat immunogenicity by fusing it with the oligomerisation domain of a chimeric C4-binding protein (C4b-p), termed IMX313, resulting in Tat heptamerisation and linked Tat to the leader sequence of tissue plasminogen activator (TPA) to ensure that the bulk of heptamerised Tat is secreted. Mice vaccinated with secreted Tat fused to IMX313 (pVAX-sTat-IMX313) developed higher titres of Tat-specific serum IgG, mucosal sIgA and cell-mediated immune (CMI) responses, and showed superior control of EcoHIV infection, a surrogate murine HIV challenge model, compared with animals vaccinated with other test vaccines. Given the crucial contribution of Tat to HIV-1 pathogenesis and the precedent of Tat-based DNA vaccines in conferring some level of protection in animal models, we believe that the virologic control demonstrated with this novel multimerised Tat vaccine highlights the promise of this vaccine candidate for humans. PMID:27358023

  5. Cholera toxin B subunit-five-stranded α-helical coiled-coil fusion protein: "five-to-five" molecular chimera displays robust physicochemical stability.

    Science.gov (United States)

    Arakawa, Takeshi; Harakuni, Tetsuya

    2014-09-03

    To create a physicochemically stable cholera toxin (CT) B subunit (CTB), it was fused to the five-stranded α-helical coiled-coil domain of cartilage oligomeric matrix protein (COMP). The chimeric fusion protein (CTB-COMP) was expressed in Pichia pastoris, predominantly as a pentamer, and retained its affinity for the monosialoganglioside GM1, a natural receptor of CT. The fusion protein displayed thermostability, tolerating the boiling temperature of water for 10min, whereas unfused CTB readily dissociated to its monomers and lost its affinity for GM1. The fusion protein also displayed resistance to strong acid at pHs as low as 0.1, and to the protein denaturant sodium dodecyl sulfate at concentrations up to 10%. Intranasal administration of the fusion protein to mice induced anti-B subunit serum IgG, even after the protein was boiled, whereas unfused CTB showed no thermostable mucosal immunogenicity. This study demonstrates that CTB fused to a pentameric α-helical coiled coil has a novel physicochemical phenotype, which may provide important insight into the molecular design of enterotoxin-B-subunit-based vaccines and vaccine delivery molecules.

  6. A novel Pseudomonas aeruginosa bacteriophage, Ab31, a chimera formed from temperate phage PAJU2 and P. putida lytic phage AF: characteristics and mechanism of bacterial resistance.

    Directory of Open Access Journals (Sweden)

    Libera Latino

    Full Text Available A novel temperate bacteriophage of Pseudomonas aeruginosa, phage vB_PaeP_Tr60_Ab31 (alias Ab31 is described. Its genome is composed of structural genes related to those of lytic P. putida phage AF, and regulatory genes similar to those of temperate phage PAJU2. The virion structure resembles that of phage AF and other lytic Podoviridae (S. enterica Epsilon 15 and E. coli phiv10 with similar tail spikes. Ab31 was able to infect P. aeruginosa strain PA14 and two genetically related strains called Tr60 and Tr162, out of 35 diverse strains from cystic fibrosis patients. Analysis of resistant host variants revealed different phenotypes, including induction of pigment and alginate overproduction. Whole genome sequencing of resistant variants highlighted the existence of a large deletion of 234 kbp in two strains, encompassing a cluster of genes required for the production of CupA fimbriae. Stable lysogens formed by Ab31 in strain Tr60, permitted the identification of the insertion site. During colonization of the lung in cystic fibrosis patients, P. aeruginosa adapts by modifying its genome. We suggest that bacteriophages such as Ab31 may play an important role in this adaptation by selecting for bacterial characteristics that favor persistence of bacteria in the lung.

  7. Ethical Arguments for the Technology of Human——animal Chimeras%关于人兽嵌合体技术的伦理辩护

    Institute of Scientific and Technical Information of China (English)

    李锐锋; 鲁琴

    2009-01-01

    人兽嵌合体技术具有巨大的医学价值和应用前景.在合理的伦理规范和必要的法律制度的监管下研究,既不会对人类的尊严造成损害,也不会导致对物种整体性的破坏;虽说使人兽嵌合体处于不自然状态,但这是所有技术的共性和常规常态;鉴于对是否存在跨物种感染的风险尚无有说服力的证据,我们应该以积极的态度、小心地试验、谨慎地应用对待这项技术,在没有充分的证据表明确实不存在跨物种感染之前,严禁进行临床研究.

  8. Immunization with recombinant bivalent chimera r-Cpae confers protection against alpha toxin and enterotoxin of Clostridium perfringens type A in murine model.

    Science.gov (United States)

    Shreya, Das; Uppalapati, Siva R; Kingston, Joseph J; Sripathy, Murali H; Batra, Harsh V

    2015-05-01

    Clostridium perfringens type A, an anaerobic pathogen is the most potent cause of soft tissue infections like gas gangrene and enteric diseases like food poisoning and enteritis. The disease manifestations are mediated via two important exotoxins, viz. myonecrotic alpha toxin (αC) and enterotoxin (CPE). In the present study, we synthesized a bivalent chimeric protein r-Cpae comprising C-terminal binding regions of αC and CPE using structural vaccinology rationale and assessed its protective efficacy against both alpha toxin (αC) and enterotoxin (CPE) respectively, in murine model. Active immunization of mice with r-Cpae generated high circulating serum IgG (systemic), significantly increased intestinal mucosal s-IgA antibody titres and resulted in substantial protection to the immunized animals (100% and 75% survival) with reduced tissue morbidity when administered with 5×LD(100) doses of αC (intramuscular) and CPE (intra-gastric gavage) respectively. Mouse RBCs and Caco-2 cells incubated with a mixture of anti-r-Cpae antibodies and αC and CPE respectively, illustrated significantly higher protection against the respective toxins. Passive immunization of mice with a similar mixture resulted in 91-100% survival at the end of the 15 days observation period while mice immunized with a concoction of sham sera and respective toxins died within 2-3 days. This work demonstrates the efficacy of the rationally designed r-Cpae chimeric protein as a potential sub unit vaccine candidate against αC and CPE of C. perfringens type A toxemia.

  9. Stem cell potency and the ability to contribute to chimeric organisms.

    Science.gov (United States)

    Polejaeva, Irina; Mitalipov, Shoukhrat

    2013-03-01

    Mouse embryonic chimeras are a well-established tool for studying cell lineage commitment and pluripotency. Experimental chimeras were successfully produced by combining two or more preimplantation embryos or by introducing into host embryo cultured pluripotent embryonic stem cells (ESCs). Chimera production using genetically modified ESCs became the method of choice for the generation of knockout or knockin mice. Although the derivation of ESCs or ESC-like cells has been reported for other species, only mouse and rat pluripotent stem cells have been shown to contribute to germline-competent chimeras, which is the defining feature of ESCs. Herein, we describe different approaches employed for the generation of embryonic chimeras, define chimera-competent cell types, and describe cases of spontaneous chimerism in humans. We also review the current state of derivation of pluripotent stem cells in several species and discuss outcomes of various chimera studies when such cells are used.

  10. 纸上谈兵也精彩"凯美拉"海军通用支援飞机设计方案%Chimera: a Naval Common Support Aircraft Concept

    Institute of Scientific and Technical Information of China (English)

    张颖; 秦五诗

    2007-01-01

    @@ 大学生团队飞机设计竞赛是AIAA组织的一系列年度航空航天设计竞赛之一,其中2000年的竞赛主题是设计一种可以取代当时服役的C-2舰上起落运输机、E-2C+舰载预警机、S-3B舰载反潜机和ES-3A舰载电子监视飞机的通用海军支援飞机,来自弗吉尼亚理工大学的"凯美拉"小组赢得了冠军.

  11. Truncated Glucagon-like Peptide-1 and Exendin-4 α-Conotoxin pl14a Peptide Chimeras Maintain Potency and α-Helicity and Reveal Interactions Vital for cAMP Signaling in Vitro.

    Science.gov (United States)

    Swedberg, Joakim E; Schroeder, Christina I; Mitchell, Justin M; Fairlie, David P; Edmonds, David J; Griffith, David A; Ruggeri, Roger B; Derksen, David R; Loria, Paula M; Price, David A; Liras, Spiros; Craik, David J

    2016-07-22

    Glucagon-like peptide-1 (GLP-1) signaling through the glucagon-like peptide 1 receptor (GLP-1R) is a key regulator of normal glucose metabolism, and exogenous GLP-1R agonist therapy is a promising avenue for the treatment of type 2 diabetes mellitus. To date, the development of therapeutic GLP-1R agonists has focused on producing drugs with an extended serum half-life. This has been achieved by engineering synthetic analogs of GLP-1 or the more stable exogenous GLP-1R agonist exendin-4 (Ex-4). These synthetic peptide hormones share the overall structure of GLP-1 and Ex-4, with a C-terminal helical segment and a flexible N-terminal tail. Although numerous studies have investigated the molecular determinants underpinning GLP-1 and Ex-4 binding and signaling through the GLP-1R, these have primarily focused on the length and composition of the N-terminal tail or on how to modulate the helicity of the full-length peptides. Here, we investigate the effect of C-terminal truncation in GLP-1 and Ex-4 on the cAMP pathway. To ensure helical C-terminal regions in the truncated peptides, we produced a series of chimeric peptides combining the N-terminal portion of GLP-1 or Ex-4 and the C-terminal segment of the helix-promoting peptide α-conotoxin pl14a. The helicity and structures of the chimeric peptides were confirmed using circular dichroism and NMR, respectively. We found no direct correlation between the fractional helicity and potency in signaling via the cAMP pathway. Rather, the most important feature for efficient receptor binding and signaling was the C-terminal helical segment (residues 22-27) directing the binding of Phe(22) into a hydrophobic pocket on the GLP-1R.

  12. Reformas de saúde em perspectiva comparada: uma questão sem fim .... ou uma busca improvável Health sector reforms in comparative perspective: an unending quest ... or chasing a chimera

    Directory of Open Access Journals (Sweden)

    James Warner Björkman

    2009-06-01

    Full Text Available Considerando a natureza problemática das tentativas de reformar os sistemas nacionais de prestação de serviços em saúde, este documento aborda o contexto e a lógica das reformas do setor. Após um retrospecto das abordagens do aumento de capacitação em três gerações de reformas do setor público, o documento examina as reformas aplicadas ao financiamento, organização e prestação dos serviços de saúde, e sugere estratégias para reformas que levem a capacidade em consideração.Given the problematic nature of attempts to reform national delivery systems for health care, the paper reviews the context and logic of reforms in the health sector. After a background on approaches to building capacity within three generations of public sector reforms, it examines the reforms applied to financing, organizing and delivering health services and suggests strategies for reform that take capacity into account.

  13. hKCNQ1/hKCNQ2嵌合体的构建,表达及电生理学特性%Construction, Expression and Characterization of hKCNQ1/hKCNQ2 Chimeras

    Institute of Scientific and Technical Information of China (English)

    王平安; 李小青; 刘艳; 张清挺; 徐舒

    2010-01-01

    目的:构建hKCNQ1/hKCNQ2嵌合体,研究嵌合体通道的电生理学特征,为分析PIP2对hKcnq1通道的调节机制打下基础.方法:利甩over-lapPCR方法构建hKCNQ1/hKCNQ2嵌合体质粒(Q1ctQ2-pCI、Q1ctQ2-pcDNA3.1),转染HEK293细胞,采用全细胞膜片钳技术记录HEK293细胞上嵌合体电流.结果:在全细胞膜片钳记录模式下,转染了嵌合体Q1ctQ2-pCI的HEK293细胞电流密度160为5.2±0.87 pA/pf,其半数激活电压V0.5为23.3±8.9 mV(n=6);转染了嵌合体Q2ctQ1-pcDNA3.1的HEK293细胞电流密度160为21.7±4.2 pA/pf,其半数激活电压V0.5为-37.5±3.6 mV(n=9).结论:成功构建了hKCNQ1/hKCNQ2嵌合体并完成了嵌合体重组质粒的异源性表达和膜片钳记录.

  14. Bone transplantation and tissue engineering, part I. Mythology, miracles and fantasy: from Chimera to the Miracle of the Black Leg of Saints Cosmas and Damian and the cock of John Hunter.

    Science.gov (United States)

    Hernigou, Philippe

    2014-12-01

    The replacement of diseased organs and tissues by the healthy ones of others has been a unique milestone in modern medicine. However, even though cloning, member transplantation and regenerative therapies with stem cells are available in the twentieth and twenty-first centuries, one should remember that all these techniques were in the imagination more than 2,000 years ago. For centuries, transplantation remained a theme of mythology, miracle or fantasy and was found only in literature and arts. This first paper explains the concept of tissue transplantation from the period when it was relegated to the imagination to the work of the Scottish surgeon and anatomist, John Hunter, who demonstrated the viability of bone allograft.

  15. Ethical Issues of Creating Human-nonhuman Chimeras and Related Applied Research in this realm%人兽嵌合体创造和应用研究中的伦理问题

    Institute of Scientific and Technical Information of China (English)

    滕菲; 李建军

    2011-01-01

    现代生物技术发展使得人善嵌合体的创造和应用研究成为可能.人善嵌合体的创造和应用研究预示着难以估童的医学价值和商业利润,但其从一开始就引起了高度的伦理关注,并在直觉的、文化的和理性的社会意识层面上引发了激烈的社会争辩,形成了有关厌恶智慧、物种界限和人类尊严的伦理现点,产生了一系列有待进一步探讨的伦理和政策问题,如人兽嵌合体的道德地位及其研究的道德合理性和社会规制问题.

  16. 重组人可溶性PDGFRβ/Fc在昆虫细胞Sf9中的表达%Expression of recombinant human soluble platelet-derived growth factor receptor Beta/Fc chimera in insect cell Sf9

    Institute of Scientific and Technical Information of China (English)

    谢秋玲; 刘兰; 刘秀贵; 张玲; 徐丽慧; 洪岸

    2009-01-01

    [目的]利用昆虫细胞Bac-to-Bac杆状病毒表达系统表达血小板源性生长因子受体β (PDGFRβ)链膜外区与人IgG Fc片段的可溶性受体融合蛋白sPDGFRβ/Fc,并检测重组蛋白的特异性和生物活性.[方法]采用Bac-to-Bac系统,构建重组转移质粒pFastbac-sPDGFRβ/Fc,转化到含穿梭载体Bacmid的感受态细胞DH10Bac中,使目的基因与杆状病毒基因组DNA发生位点特异性重组,获得重组病毒DNA,将其通过脂质体转染昆虫细胞Sf9获得重组病毒.将该重组病毒感染Sf9无血清细胞系,在Sf9细胞中表达sPDGFRβ/Fc,对表达产物进行Western blotting检测和Protein A亲合层析纯化,并进一步通过MTT法检测获得的重组蛋白生物学活性.[结果]重组病毒感染Sf9细胞后,经Western blotting分析,能检测到一条分子量约为97 kDa的特异性条带,与目的蛋白大小相符.通过Protein A亲和层析,获得了纯度达75%以上,表达量为1 μg/mL细胞培养上清的重组融合蛋白,MTT结果显示该重组融合蛋白sPDGFRβ/Fc具有抑制PDGF刺激的Balb/c 3T3细胞增殖的能力.[结论]具有生物活性的重组可溶性受体融合蛋白sPDGFRβ/Fc可在昆虫细胞中成功地得到表达.

  17. Experiment list: SRX837357 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ource_name=ChIP-Seq with MyoD antibody 6975 in mouse P19 cells transduced with MD(ND2bHLH) chimera || cell l...ine=P19 || transduction=MD(ND2bHLH) chimera || chip antibody=MyoD antibody 6975 h

  18. Experiment list: SRX837356 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ource_name=ChIP-Seq with MyoD antibody 6196 in mouse P19 cells transduced with MD(ND2bHLH) chimera || cell l...ine=P19 || transduction=MD(ND2bHLH) chimera || chip antibody=MyoD antibody 6196 h

  19. A prourokinase-RGDS chimera——Construction, expression and characterization

    Institute of Scientific and Technical Information of China (English)

    钱斌; 孙迎庆; 郭雁; 党昕; 茹炳根

    1999-01-01

    A tetrapeptide, RGDS, was inserted into proUK kringle domain G118-L119 by the construction of a mutant proUK-RGDS gene. The gene was expressed in the baculovirus expression system. Immunoaffinity chromatography was used to purify the chimera and protein with purity over 90% was achieved. The chimera was tested for its platelet membrane binding function and showed a calcium-dependent platelet binding activity. Amidolytic activity of the chimera was tested. The result indicated that specific amidolytic activity of plasmin activated chimera was 62000 IU/mg, comparable to the previously reported 65 355 IU/mg of plasmin activated natural proUK. Activation of plasminogen by the chimera after plasmin treatment followed Micbieal-Menten kinetics, and the Km was 0.97 μmol/L, which was also comparable to 1.64 μmol/L of native urokinase. The chimera also showed intensive ability to inhibit platelet aggregation in vitro. These results indicate that this chimera might be useful as a bifunctional thrombolytic agent.

  20. Long-range Transcriptome Sequencing Reveals Cancer Cell Growth Regulatory Chimeric mRNA

    Directory of Open Access Journals (Sweden)

    Roberto Plebani

    2012-11-01

    Full Text Available mRNA chimeras from chromosomal translocations often play a role as transforming oncogenes. However, cancer transcriptomes also contain mRNA chimeras that may play a role in tumor development, which arise as transcriptional or post-transcriptional events. To identify such chimeras, we developed a deterministic screening strategy for long-range sequence analysis. High-throughput, long-read sequencing was then performed on cDNA libraries from major tumor histotypes and corresponding normal tissues. These analyses led to the identification of 378 chimeras, with an unexpectedly high frequency of expression (≈2 x 10-5 of all mRNA. Functional assays in breast and ovarian cancer cell lines showed that a large fraction of mRNA chimeras regulates cell replication. Strikingly, chimeras were shown to include both positive and negative regulators of cell growth, which functioned as such in a cell-type-specific manner. Replication-controlling chimeras were found to be expressed by most cancers from breast, ovary, colon, uterus, kidney, lung, and stomach, suggesting a widespread role in tumor development.

  1. De la leyenda criminológica a la quimera criminológica …A través de la mitología penal… Ensayo observacional, experimental, situacional y prospectivo/From criminological legend to the criminological chimera …Through criminal mythology... Observational, experimental, situational and prospective trial

    Directory of Open Access Journals (Sweden)

    Gino Ríos Patio

    2015-08-01

    Full Text Available The essayist presents his personal view on the past, present and future of criminology and criminal law, using metaphors of legend, myth and illusion, as a system of popular beliefs about real phenomena that are intended to conceal the true purpose for which they are built and maintained, explaining and justifying the status quo through the history of peoples.

  2. Mouse embryos' fusion for the tetraploid complementation assay.

    Science.gov (United States)

    Gertsenstein, Marina

    2015-01-01

    Production of the germline-competent chimeras using genetically modified ES cell lines is an essential step in the establishment of novel mouse models. In addition chimeras provide a powerful tool to study the cell lineage and to analyze complex phenotypes of mutant mice. Mouse chimeras with tetraploid embryos are used to rescue extraembryonic defects, to analyze an impact of gene function on specific lineage, to study the interaction between embryonic and extraembryonic tissues, and to produce mutant embryos and mice for the phenotype analysis. Tetraploid embryos are generated by the fusion of two blastomeres of the mouse embryo. The applications of tetraploid complementation assay and the protocol are described below.

  3. Near Real-time Data Analysis of Core-Collapse Supernova Simulations With Bellerophon

    Energy Technology Data Exchange (ETDEWEB)

    Lingerfelt, Eric J [ORNL; Messer, Bronson [ORNL; Desai, Sharvari S [University of Tennessee, Knoxville (UTK); Holt, Chastity A [Appalachian State University; Lentz, Eric J [University of Tennessee, Knoxville (UTK)

    2014-01-01

    We present an overview of a software system, Bellerophon, built to support a production-level HPC application called CHIMERA, which simulates core-collapse supernova events at the petascale. Developed over the last four years, Bellerophon enables CHIMERA s geographically dispersed team of collaborators to perform data analysis in near real-time. Its n-tier architecture provides an encapsulated, end-to-end software solution that enables the CHIMERA team to quickly and easily access highly customizable animated and static views of results from anywhere in the world via a web-deliverable, cross-platform desktop application. In addition, Bellerophon addresses software engineering tasks for the CHIMERA team by providing an automated mechanism for performing regression testing on a variety of supercomputing platforms. Elements of the team s workflow management needs are met with software tools that dynamically generate code repository statistics, access important online resources, and monitor the current status of several supercomputing resources.

  4. State-of-the-Art Fusion-Finder Algorithms Sensitivity and Specificity

    Directory of Open Access Journals (Sweden)

    Matteo Carrara

    2013-01-01

    Full Text Available Background. Gene fusions arising from chromosomal translocations have been implicated in cancer. RNA-seq has the potential to discover such rearrangements generating functional proteins (chimera/fusion. Recently, many methods for chimeras detection have been published. However, specificity and sensitivity of those tools were not extensively investigated in a comparative way. Results. We tested eight fusion-detection tools (FusionHunter, FusionMap, FusionFinder, MapSplice, deFuse, Bellerophontes, ChimeraScan, and TopHat-fusion to detect fusion events using synthetic and real datasets encompassing chimeras. The comparison analysis run only on synthetic data could generate misleading results since we found no counterpart on real dataset. Furthermore, most tools report a very high number of false positive chimeras. In particular, the most sensitive tool, ChimeraScan, reports a large number of false positives that we were able to significantly reduce by devising and applying two filters to remove fusions not supported by fusion junction-spanning reads or encompassing large intronic regions. Conclusions. The discordant results obtained using synthetic and real datasets suggest that synthetic datasets encompassing fusion events may not fully catch the complexity of RNA-seq experiment. Moreover, fusion detection tools are still limited in sensitivity or specificity; thus, there is space for further improvement in the fusion-finder algorithms.

  5. Role of HIV-1 subtype C envelope V3 to V5 regions in viral entry, coreceptor utilization and replication efficiency in primary T-lymphocytes and monocyte-derived macrophages

    Directory of Open Access Journals (Sweden)

    Gopalan Sarla

    2007-11-01

    Full Text Available Abstract Background Several subtypes of HIV-1 circulate in infected people worldwide, including subtype B in the United States and subtype C in Africa and India. To understand the biological properties of HIV-1 subtype C, including cellular tropism, virus entry, replication efficiency and cytopathic effects, we reciprocally inserted our previously characterized envelope V3–V5 regions derived from 9 subtype C infected patients from India into a subtype B molecular clone, pNL4-3. Equal amounts of the chimeric viruses were used to infect T-lymphocyte cell lines (A3.01 and MT-2, coreceptor cell lines (U373-MAGI-CCR5/CXCR4, primary blood T-lymphocytes (PBL and monocyte-derived macrophages (MDM. Results We found that subtype C envelope V3–V5 region chimeras failed to replicate in T-lymphocyte cell lines but replicated in PBL and MDM. In addition, these chimeras were able to infect U373MAGI-CD4+-CCR5+ but not U373MAGI-CD4+-CXCR4+ cell line, suggesting CCR5 coreceptor utilization and R5 phenotypes. These subtype C chimeras were unable to induce syncytia in MT-2 cells, indicative of non-syncytium inducing (NSI phenotypes. More importantly, the subtype C envelope chimeras replicated at higher levels in PBL and MDM compared with subtype B chimeras and isolates. Furthermore, the higher levels subtype C chimeras replication in PBL and MDM correlated with increased virus entry in U373MAGI-CD4+-CCR5+. Conclusion Taken together, these results suggest that the envelope V3 to V5 regions of subtype C contributed to higher levels of HIV-1 replication compared with subtype B chimeras, which may contribute to higher viral loads and faster disease progression in subtype C infected individuals than other subtypes as well as rapid HIV-1 subtype C spread in India.

  6. Preliminary study for the detection of neutrons in heavy-ion collisions with charged particle detectors

    Directory of Open Access Journals (Sweden)

    Auditore L.

    2015-01-01

    Full Text Available At Laboratori Nazionali del Sud (LNS the CHIMERA 4π multidetector has been designed and setup to detect charged particles emitted in heavy ion collisions at intermediate energies. Properties and performances of CHIMERA have been widely demonstrated by published results obtained in the performed experiments. Moreover, in recent years, a new charged particle detector (ChPD for correlation studies (FARCOS has been designed, and recently a first prototype has been coupled to CHIMERA, in order to test performances in view of correlation measurements in coincidence with 4π detectors. Simultaneous neutrons and charged particles detection in heavy ion collisions represents an important experimental progress for future experiments to be performed with both stable and exotic nuclei. In order to investigate about this possibility, simple Monte Carlo simulations have been performed. Preliminary simulations have been carried out by means of MCNPX transport code to evaluate the perturbation effects, including cross-talk and time response, induced in CHIMERA and/or FARCOS Si-CsI(Tl telescopes on (typical 20MeV neutron signals coming froma typical reaction in heavy ion collisions at the Fermi energy. Moreover, first data analysis results of the INKIISSY experiment indicates sizable probability to detect neutrons by properly shadowing CHIMERA Si-CsI(Tl telescopes. Analysis is still in progress.

  7. Experimental multistable states for small network of coupled pendula

    Science.gov (United States)

    Dudkowski, Dawid; Grabski, Juliusz; Wojewoda, Jerzy; Perlikowski, Przemyslaw; Maistrenko, Yuri; Kapitaniak, Tomasz

    2016-07-01

    Chimera states are dynamical patterns emerging in populations of coupled identical oscillators where different groups of oscillators exhibit coexisting synchronous and incoherent behaviors despite homogeneous coupling. Although these states are typically observed in the large ensembles of oscillators, recently it has been shown that so-called weak chimera states may occur in the systems with small numbers of oscillators. Here, we show that similar multistable states demonstrating partial frequency synchronization, can be observed in simple experiments with identical mechanical oscillators, namely pendula. The mathematical model of our experiment shows that the observed multistable states are controlled by elementary dynamical equations, derived from Newton’s laws that are ubiquitous in many physical and engineering systems. Our finding suggests that multistable chimera-like states are observable in small networks relevant to various real-world systems.

  8. TLR7 influences germinal center selection in murine SLE.

    Science.gov (United States)

    Boneparth, Alexis; Huang, Weiqing; Bethunaickan, Ramalingam; Woods, Megan; Sahu, Ranjit; Arora, Shitij; Akerman, Meredith; Lesser, Martin; Davidson, Anne

    2015-01-01

    TLR7 enhances germinal center maturation and migration of B cells to the dark zone where proliferation and somatic hypermutation occur. Our goal was to determine how Tlr7 dose influences selection of the autoreactive B cell repertoire in NZW/BXSB. Yaa mice bearing the site-directed heavy chain transgene 3H9 that encodes for the TLR7 regulated anti-CL response. To create a physiologic setting in which autoreactive B cells compete for survival with non-autoreactive B cells, we generated bone marrow chimeras in which disease onset occurred with similar kinetics and the transferred 3H9+ female non-Yaa, male Yaa or male TLR7(-/Yaa) cells could be easily identified by positivity for GFP. Deletion of 3H9 B cells occurred in the bone marrow and the remaining 3H9 follicular B cells manifested a decrease in surface IgM. Although there were differences in the naïve repertoire between the chimeras it was not possible to distinguish a clear pattern of selection against lupus related autoreactivity in TLR7(-/Yaa) or female chimeras. By contrast, preferential expansion of 3H9+ B cells occurred in the germinal centers of male Yaa chimeras. In addition, although all chimeras preferentially selected 3H9/Vκ5 encoded B cells into the germinal center and plasma cell compartments, 3H9 male Yaa chimeras had a more diverse repertoire and positively selected the 3H9/Vκ5-48/Jκ4 pair that confers high affinity anti-cardiolipin activity. We were unable to demonstrate a consistent effect of Tlr7 dose or Yaa on somatic mutations. Our data show that TLR7 excess influences the selection, expansion and diversification of B cells in the germinal center, independent of other genes in the Yaa locus.

  9. Correlation analysis of the coherence-incoherence transition in a ring of nonlocally coupled logistic maps

    Science.gov (United States)

    Vadivasova, Tatiana E.; Strelkova, Galina I.; Bogomolov, Sergey A.; Anishchenko, Vadim S.

    2016-09-01

    We present numerical results for a set of bifurcations occurring at the transition from complete chaotic synchronization to spatio-temporal chaos in a ring of nonlocally coupled chaotic logistic maps. The regularities are established for the evolution of cross-correlations of oscillations in the network elements at the bifurcations related to the coupling strength variation. We reveal the distinctive features of cross-correlations for phase and amplitude chimera states. It is also shown that the effect of time intermittency between the amplitude and phase chimeras can be realized in the considered ensemble.

  10. How does domain replacement affect fibril formation of the rabbit/human prion proteins.

    Directory of Open Access Journals (Sweden)

    Xu Yan

    Full Text Available It is known that in vivo human prion protein (PrP have the tendency to form fibril deposits and are associated with infectious fatal prion diseases, while the rabbit PrP does not readily form fibrils and is unlikely to cause prion diseases. Although we have previously demonstrated that amyloid fibrils formed by the rabbit PrP and the human PrP have different secondary structures and macromolecular crowding has different effects on fibril formation of the rabbit/human PrPs, we do not know which domains of PrPs cause such differences. In this study, we have constructed two PrP chimeras, rabbit chimera and human chimera, and investigated how domain replacement affects fibril formation of the rabbit/human PrPs.As revealed by thioflavin T binding assays and Sarkosyl-soluble SDS-PAGE, the presence of a strong crowding agent dramatically promotes fibril formation of both chimeras. As evidenced by circular dichroism, Fourier transform infrared spectroscopy, and proteinase K digestion assays, amyloid fibrils formed by human chimera have secondary structures and proteinase K-resistant features similar to those formed by the human PrP. However, amyloid fibrils formed by rabbit chimera have proteinase K-resistant features and secondary structures in crowded physiological environments different from those formed by the rabbit PrP, and secondary structures in dilute solutions similar to the rabbit PrP. The results from transmission electron microscopy show that macromolecular crowding caused human chimera but not rabbit chimera to form short fibrils and non-fibrillar particles.We demonstrate for the first time that the domains beyond PrP-H2H3 (β-strand 1, α-helix 1, and β-strand 2 have a remarkable effect on fibrillization of the rabbit PrP but almost no effect on the human PrP. Our findings can help to explain why amyloid fibrils formed by the rabbit PrP and the human PrP have different secondary structures and why macromolecular crowding has different

  11. The effect of immunosuppression on function of kidney allografts in the rat

    NARCIS (Netherlands)

    R.W.F. de Bruin (Ron)

    1970-01-01

    textabstractTransplantation of living tissues is not a new concept. Greek mythology presents us with the Chimera in which a goat's body, a lion's head and a dragon's tail are joined to form a terrifying monster. Ancient Indian surgeons made use of local skin flaps for rhinoplasty, an art which has b

  12. Domain Modeling: NP_001095856.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available T-BETA-GAMMA SUBUNITS c1gota_ chr7/NP_001095856.1/NP_001095856.1_holo_6-347.pdb blast 41A,42G,43E,44S,45G,46...NP_001095856.1 chr7 HETEROTRIMERIC COMPLEX OF A GT-ALPHA/GI-ALPHA CHIMERA AND THE G

  13. Domain Modeling: NP_055672.3 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_055672.3 chr1 Solution structure of the chimera of the C-terminal PID domain of ...Fe65L and the C-terminal tail peptide of APP p2ysza_ chr1/NP_055672.3/NP_055672.3_apo_116-314.pdb swppa 0 ...

  14. Design of chimeric proteins by combination of subdomain-sized fragments.

    Science.gov (United States)

    Rico, José Arcadio Farías; Höcker, Birte

    2013-01-01

    Hybrid proteins or chimeras are generated by recombination of protein fragments. In the course of evolution, this mechanism has led to major diversification of protein folds and their functionalities. Similarly, protein engineers have taken advantage of this attractive strategy to build new proteins. Methods that use homologous recombination have been developed to (semi) randomly create chimeras from which the best can be selected. We wanted to recombine very divergent or even unrelated fragments, which is not possible with these methods. Consequently, based on the observation that nature evolves new proteins also through illegitimate recombination, we developed a strategy to design chimeras using protein fragments from different folds. For this approach, we employ detailed structure comparisons, and based on structural similarities, we choose the fragments used for recombination. Model building and minimization can be used to assess the design, and further optimization can be performed using established computational design methodologies. Here, we outline a general approach to rational protein chimera design based on our experience, and provide considerations for the selection of the fragments, the evaluation, and possible redesign of the constructs.

  15. Mosaic origins of a complex chimeric mitochondrial gene in Silene vulgaris.

    Directory of Open Access Journals (Sweden)

    Helena Storchova

    Full Text Available Chimeric genes are significant sources of evolutionary innovation that are normally created when portions of two or more protein coding regions fuse to form a new open reading frame. In plant mitochondria astonishingly high numbers of different novel chimeric genes have been reported, where they are generated through processes of rearrangement and recombination. Nonetheless, because most studies do not find or report nucleotide variation within the same chimeric gene, evolution after the origination of these chimeric genes remains unstudied. Here we identify two alleles of a complex chimera in Silene vulgaris that are divergent in nucleotide sequence, genomic position relative to other mitochondrial genes, and expression patterns. Structural patterns suggest a history partially influenced by gene conversion between the chimeric gene and functional copies of subunit 1 of the mitochondrial ATP synthase gene (atp1. We identified small repeat structures within the chimeras that are likely recombination sites allowing generation of the chimera. These results establish the potential for chimeric gene divergence in different plant mitochondrial lineages within the same species. This result contrasts with the absence of diversity within mitochondrial chimeras found in crop species.

  16. The Developmental Potential of iPSCs Is Greatly Influenced by Reprogramming Factor Selection

    NARCIS (Netherlands)

    Buganim, Yosef; Markoulaki, Styliani; van Wietmarschen, Niek; Hoke, Heather; Wu, Tao; Ganz, Kibibi; Akhtar-Zaidi, Batool; He, Yupeng; Abraham, Brian J.; Porubsky, David; Kulenkampff, Elisabeth; Faddah, Dina A.; Shi, Linyu; Gao, Qing; Sarkar, Sovan; Cohen, Malkiel; Goldmann, Johanna; Nery, Joseph R.; Schultz, Matthew D.; Ecker, Joseph R.; Xiao, Andrew; Young, Richard A.; Lansdorp, Peter M.; Jaenisch, Rudolf

    2014-01-01

    Induced pluripotent stem cells (iPSCs) are commonly generated by transduction of Oct4, Sox2, Klf4, and Myc (OSKM) into cells. Although iPSCs are pluripotent, they frequently exhibit high variation in terms of quality, as measured in mice by chimera contribution and tetraploid complementation. Reliab

  17. Developmental biotechnology for aquaculture, with special reference to surrogate production in teleost fishes

    Science.gov (United States)

    Yamaha, Etsuro; Saito, Taiju; Goto-Kazeto, Rie; Arai, Katsutoshi

    2007-07-01

    This review introduces surrogate production as a new technique for fish-seed production in aquaculture. Surrogate production in fish is a technique used to obtain the gametes of a certain genotype through the gonad of another genotype. It is achieved by inducing germ-line chimerism between different species during early development. Primordial germ cells (PGCs) are the key material of this technique to induce germ-line chimera. In several species, it has been reported that PGCs differentiated from the blastomeres inherited some maternally supplied mRNA located in the terminal regions of the early cleavage furrows. PGCs from donor species (or strains) are isolated and transplanted into host species to induce the germ-line chimera. Four methods for inducing germ-line chimera are described: blastomere transplantation, blastoderm-graft transplantation, transplantation of PGC from the genital ridge, and transplantation visualised PGC with GFP fluorescence. Several problems preventing the successful induction of germ-line chimera in various fish species are discussed. Surrogate production, however, opens the possibility of efficient fish-seed production and effective breeding and transfer of biodiversity to an aquaculture strain. Conservation and efficient utilisation of genetic resources will be achieved through surrogate production combined with the cryopreservation of PGCs.

  18. TRANSIENT AND PERMANENT ENGRAFTMENT POTENTIAL OF MURINE HEMATOPOIETIC STEM-CELL SUBSETS - DIFFERENTIAL-EFFECTS OF HOST CONDITIONING WITH GAMMA-RADIATION AND CYTOTOXIC DRUGS

    NARCIS (Netherlands)

    DOWN, JD; PLOEMACHER, RE

    1993-01-01

    Transplant of sorted donor (BG-Gpi-1(a)) hematopoietic stem cell subsets and host (BG-Gpi-1(b)) treatment with total body irradiation (TBI) or cytotoxic drugs were compared for induction of short- and long-term engraftment in a murine chimera model of congenic bone marrow transplantation (BMT). Para

  19. Functional analysis of the epidermal-specific MYB genes CAPRICE and WEREWOLF in Arabidopsis.

    Science.gov (United States)

    Tominaga, Rumi; Iwata, Mineko; Okada, Kiyotaka; Wada, Takuji

    2007-07-01

    Epidermis cell differentiation in Arabidopsis thaliana is a model system for understanding the developmental end state of plant cells. Two types of MYB transcription factors, R2R3-MYB and R3-MYB, are involved in cell fate determination. To examine the molecular basis of this process, we analyzed the functional relationship of the R2R3-type MYB gene WEREWOLF (WER) and the R3-type MYB gene CAPRICE (CPC). Chimeric constructs made from the R3 MYB regions of WER and CPC used in reciprocal complementation experiments showed that the CPC R3 region cannot functionally substitute for the WER R3 region in the differentiation of hairless cells. However, WER R3 can substantially substitute for CPC R3. There are no differences in yeast interaction assays of WER or WER chimera proteins with GLABRA3 (GL3) or ENHANCER OF GLABRA3 (EGL3). CPC and CPC chimera proteins also have similar activity in preventing GL3 WER and EGL3 WER interactions. Furthermore, we showed by gel mobility shift assays that WER chimera proteins do not bind to the GL2 promoter region. However, a CPC chimera protein, which harbors the WER R3 motif, still binds to the GL2 promoter region.

  20. Isospin dependence of physical observables in Incomplete Fusion reactions at 25 MeV/nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Lombardo, I., E-mail: ilombardo@lns.infn.i [Dipartimento di Fisica, Universita di Catania, Catania (Italy); INFN Laboratori Nazionali del Sud, Catania (Italy); Agodi, C.; Alba, R. [INFN Laboratori Nazionali del Sud, Catania (Italy); Amorini, F. [INFN, Sezione di Catania, Catania (Italy); Dipartimento di Fisica, Universita di Catania, Catania (Italy); Anzalone, A. [INFN Laboratori Nazionali del Sud, Catania (Italy); Berceanu, I. [Institute for Physics and Nuclear Engineering, Bucharest (Romania); Cardella, G. [INFN, Sezione di Catania, Catania (Italy); Cavallaro, S. [Dipartimento di Fisica, Universita di Catania, Catania (Italy); INFN Laboratori Nazionali del Sud, Catania (Italy); Chatterjee, M.B. [Saha Institute of Nuclear Physics, Kolkata (India); Coniglione, R. [INFN Laboratori Nazionali del Sud, Catania (Italy); DeFilippo, E. [INFN, Sezione di Catania, Catania (Italy); DiPietro, A.; Figuera, P. [INFN Laboratori Nazionali del Sud, Catania (Italy); Geraci, E.; Giuliani, G.; Grassi, L. [Dipartimento di Fisica, Universita di Catania, Catania (Italy); INFN, Sezione di Catania, Catania (Italy); Grzeszczuk, A. [Institute of Physics, University of Silesia, Katowice (Poland); LaGuidara, E. [INFN, Sezione di Catania, Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Lanzalone, G. [INFN Laboratori Nazionali del Sud, Catania (Italy); Libera Universita Kore, Enna (Italy); LeNeindre, N. [LPC Caen, CNRS-IN2P3, ENSICAEN, Universite de Caen, Caen (France)

    2010-03-01

    Isospin dependence of dynamical and thermodynamical physical quantities observed in the reactions {sup 40}Ca + {sup 40,48}Ca and {sup 40}Ca + {sup 46}Ti at 25 MeV/nucleon has been analyzed by means of the CHIMERA multi-detector.

  1. Network Authentication Protocol Studies

    Science.gov (United States)

    2009-04-01

    Jambalaya tools [7], the Bauhaus group and its Bauhaus Toolkit [13], and the Software Engineering Research Laboratory with the Chimera, InfiniTe, and...Language, Feb. 2006. [11] The Graphviz: Graph visualization software, Mar. 2006. [12] KAON2, 2006. [13] Project Bauhaus , 2006. [14] RTCA website, Mar

  2. Chimeric creatures in Greek mythology and reflections in science.

    Science.gov (United States)

    Bazopoulou-Kyrkanidou, E

    2001-04-15

    "The Chimaera" in Homer's Iliad, "was of divine stock, not of men, in the forepart a lion, in the hinder a serpent, and in the midst a goat, ellipsis Bellerophon slew her, trusting in the signs of the gods." In Hesiod's Theogony it is emphasized that "Chimaera ellipsis had three heads, one of a grim-eyed lion, another of a goat, and another of a snakeellipsis". In addition to this interspecies animal chimera, human/animal chimeras are referred to in Greek mythology, preeminent among them the Centaurs and the Minotaur. The Centaurs, as horse/men, first appear in Geometric and early Archaic art, but in the literature not until early in the fifth century B.C. The bullheaded-man Minotaur, who is not certainly attested in the literary evidence until circa 500 B.C., first appears in art about 650 B.C. Attempts, in the fourth century B.C. and thereafter, to rationalize their mythical appearance were in vain; their chimeric nature retained its fascinating and archetypal form over the centuries. Early in the 1980s, experimental sheep/goat chimeras were produced removing the reproductive barrier between these two animal species. Late in the 1990s, legal, political, ethical, and moral fights loomed over a patent bid on human/animal chimeras. Chimeric technology is recently developed; however, the concept of chimerism has existed in literary and artistic form in ancient mythology. This is yet another example where art and literature precede scientific research and development.

  3. Antibody-mediated enhancement of human immunodeficiency virus type 1 infectivity is determined by the structure of gp120 and depends on modulation of the gp120-CCR5 interaction

    NARCIS (Netherlands)

    C. Guillon (Christophe); M. Schutten (Martin); P.H.M. Boers (Patrick); R.A. Gruters (Rob); A.D.M.E. Osterhaus (Albert)

    2002-01-01

    textabstractIn this study, we characterized the viral determinants of coreceptor usage in relation to susceptibility to antibody-mediated neutralization or enhancement of infectivity by using chimeras of three highly related human immunodeficiency virus type 1 (HIV-1) isolates of different phenotype

  4. Experiment list: SRX760601 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available and Dow, 3rd ed.) 13548159,98.2,10.5,150 GSM1546016: MC f10 Chimera Lung1 K4Me1; Mus musculus; ChIP-Seq source_name=Lung macrophages... with CD45.1 mark || strain=C57BL/6 || tissue=Lung || cell type=Lung macrophages

  5. Impaired perception of temporal fine structure and musical timbre in cochlear implant users.

    Science.gov (United States)

    Heng, Joseph; Cantarero, Gabriela; Elhilali, Mounya; Limb, Charles J

    2011-10-01

    Cochlear implant (CI) users demonstrate severe limitations in perceiving musical timbre, a psychoacoustic feature of sound responsible for 'tone color' and one's ability to identify a musical instrument. The reasons for this limitation remain poorly understood. In this study, we sought to examine the relative contributions of temporal envelope and fine structure for timbre judgments, in light of the fact that speech processing strategies employed by CI systems typically employ envelope extraction algorithms. We synthesized "instrumental chimeras" that systematically combined variable amounts of envelope and fine structure in 25% increments from two different source instruments with either sustained or percussive envelopes. CI users and normal hearing (NH) subjects were presented with 150 chimeras and asked to determine which instrument the chimera more closely resembled in a single-interval two-alternative forced choice task. By combining instruments with similar and dissimilar envelopes, we controlled the valence of envelope for timbre identification and compensated for envelope reconstruction from fine structure information. Our results show that NH subjects utilize envelope and fine structure interchangeably, whereas CI subjects demonstrate overwhelming reliance on temporal envelope. When chimeras were created from dissimilar envelope instrument pairs, NH subjects utilized a combination of envelope (p = 0.008) and fine structure information (p = 0.009) to make timbre judgments. In contrast, CI users utilized envelope information almost exclusively to make timbre judgments (p timbre judgments (p musical timbre in CI users.

  6. Requirement for Tumor Necrosis Factor Receptor 2 Expression on Vascular Cells To Induce Experimental Cerebral Malaria

    OpenAIRE

    Stoelcker, Benjamin; Hehlgans, Thomas; Weigl, Karin; Bluethmann, Horst; Grau, Georges E.; Männel, Daniela N

    2002-01-01

    Using tumor necrosis factor receptor type 2 (TNFR2)-deficient mice and generating bone marrow chimeras which express TNFR2 on either hematopoietic or nonhematopoietic cells, we demonstrated the requirement for TNFR2 expression on tissue cells to induce lethal cerebral malaria. Thus, TNFR2 on the brain vasculature mediates tumor necrosis factor-induced neurovascular lesions in experimental cerebral malaria.

  7. The N Terminus of Sarcolipin Plays an Important Role in Uncoupling Sarco-endoplasmic Reticulum Ca2+-ATPase (SERCA) ATP Hydrolysis from Ca2+ Transport

    DEFF Research Database (Denmark)

    Sahoo, Sanjaya K; Shaikh, Sana A; Sopariwala, Danesh H;

    2015-01-01

    to bind SERCA throughout its kinetic cycle and promotes uncoupling of Ca(2+) transport from ATP hydrolysis. To determine the structural regions of SLN that mediate uncoupling of SERCA, we employed mutagenesis and generated chimeras of PLB and SLN. In this study we demonstrate that deletion of SLN N...

  8. Päevalehe kujundas võitis auhindu / Sergo Selder

    Index Scriptorium Estoniae

    Selder, Sergo

    2005-01-01

    Kesk- ja Idaeuroopa kujunduskonkursist Chimera. 2005. aastal võitis kogukujunduse ja uue kujunduse auhinna Eesti Päevaleht ja parima esilehe auhinna Äripäev. Žürii esimeheks oli Maailma ajalehekujundajate organistasiooni SND (Society for News Design) president Bill Gaspard

  9. External and semi-internal controls for PCR amplification of homologous sequences in mixed templates

    DEFF Research Database (Denmark)

    Kalle, Elena; Gulevich, Alexander; Rensing, Christopher Günther T

    2013-01-01

    In a mixed template, the presence of homologous target DNA sequences creates environments that almost inevitably give rise to artifacts and biases during PCR. Heteroduplexes, chimeras, and skewed template-to-product ratios are the exclusive attributes of mixed template PCR and never occur in a si...

  10. A VMEbus interface for multi-detector trigger and control system

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    MUSE (MUltiplicity SElector) is the trigger and control system of CHIMERA, a 4π charged particles detector. Initialization of MUSE can be performed via VMEbus. This paper describes the design of VMEbus interface and functional module in MUSE, and briefs an application of MUSE.

  11. Domain Modeling: NP_037474.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_037474.1 chr19 Structure of an acetylated Rsc4 tandem bromodomain Histone Chimer...a p2r0sa_ chr19/NP_037474.1/NP_037474.1_apo_34-223.pdb p2r10a_ chr19/NP_037474.1/NP_037474.1_holo_34-223.pdb

  12. Spatial coexistence of synchronized oscillation and death: A chimeralike state

    Science.gov (United States)

    Dutta, Partha Sharathi; Banerjee, Tanmoy

    2015-10-01

    We report an interesting spatiotemporal state, namely the chimeralike incongruous coexistence of synchronized oscillation and stable steady state (CSOD) in a network of nonlocally coupled oscillators. Unlike the chimera and chimera death state, in the CSOD state identical oscillators are self-organized into two coexisting spatially separated domains: In one domain neighboring oscillators show synchronized oscillation and in another domain the neighboring oscillators randomly populate either a synchronized oscillating state or a stable steady state (we call it a death state). We consider a realistic ecological network and show that the interplay of nonlocality and coupling strength results in two routes to the CSOD state: One is from a coexisting mixed state of amplitude chimera and death, and another one is from a globally synchronized state. We provide a qualitative explanation of the origin of this state. We further explore the importance of this study in ecology that gives insight into the relationship between spatial synchrony and global extinction of species. We believe this study will improve our understanding of chimera and chimeralike states.

  13. Zona occludens-2 is critical for blood-testis barrier integrity and male fertility.

    Science.gov (United States)

    Xu, Jianliang; Anuar, Farhana; Ali, Safiah Mohamed; Ng, Mei Yong; Phua, Dominic C Y; Hunziker, Walter

    2009-10-01

    Tight junction integral membrane proteins such as claudins and occludin are tethered to the actin cytoskeleton by adaptor proteins, notably the closely related zonula occludens (ZO) proteins ZO-1, ZO-2, and ZO-3. All three ZO proteins have recently been inactivated in mice. Although ZO-3 knockout mice lack an obvious phenotype, animals deficient in ZO-1 or ZO-2 show early embryonic lethality. Here, we rescue the embryonic lethality of ZO-2 knockout mice by injecting ZO-2(-/-) embryonic stem (ES) cells into wild-type blastocysts to generate viable ZO-2 chimera. ZO-2(-/-) ES cells contribute extensively to different tissues of the chimera, consistent with an extraembryonic requirement for ZO-2 rather than a critical role in epiblast development. Adult chimera present a set of phenotypes in different organs. In particular, male ZO-2 chimeras show reduced fertility and pathological changes in the testis. Lanthanum tracer experiments show a compromised blood-testis barrier. Expression levels of ZO-1, ZO-3, claudin-11, and occludin are not apparently affected. ZO-1 and occludin still localize to the blood-testis barrier region, but claudin-11 is less well restricted and the localization of connexin-43 is perturbed. The critical role of ZO-2 for male fertility and blood-testis barrier integrity thus provides a first example for a nonredundant role of an individual ZO protein in adult mice.

  14. Chimeric rhinoviruses displaying MPER epitopes elicit anti-HIV neutralizing responses.

    Directory of Open Access Journals (Sweden)

    Guohua Yi

    Full Text Available BACKGROUND: The development of an effective AIDS vaccine has been a formidable task, but remains a critical necessity. The well conserved membrane-proximal external region (MPER of the HIV-1 gp41 glycoprotein is one of the crucial targets for AIDS vaccine development, as it has the necessary attribute of being able to elicit antibodies capable of neutralizing diverse isolates of HIV. METHODOLOGY/PRINCIPLE FINDINGS: Guided by X-ray crystallography, molecular modeling, combinatorial chemistry, and powerful selection techniques, we designed and produced six combinatorial libraries of chimeric human rhinoviruses (HRV displaying the MPER epitopes corresponding to mAbs 2F5, 4E10, and/or Z13e1, connected to an immunogenic surface loop of HRV via linkers of varying lengths and sequences. Not all libraries led to viable chimeric viruses with the desired sequences, but the combinatorial approach allowed us to examine large numbers of MPER-displaying chimeras. Among the chimeras were five that elicited antibodies capable of significantly neutralizing HIV-1 pseudoviruses from at least three subtypes, in one case leading to neutralization of 10 pseudoviruses from all six subtypes tested. CONCLUSIONS: Optimization of these chimeras or closely related chimeras could conceivably lead to useful components of an effective AIDS vaccine. While the MPER of HIV may not be immunodominant in natural infection by HIV-1, its presence in a vaccine cocktail could provide critical breadth of protection.

  15. THE EXTENT OF CLONAL STRUCTURE IN DIFFERENT LYMPHOID ORGANS

    NARCIS (Netherlands)

    HERMANS, MHA; WUBBENA, A; KROESE, FGM; HUNT, SV; COWAN, R; OPSTELTEN, D

    1992-01-01

    To gain insight into the clonal organization of lymphoid organs, we studied the distribution in situ of donor-derived cells in near-physiological chimeras. We introduced RT7b fetal liver cells into nonirradiated congenic RT7a neonatal rats. The chimerism 6-20 wk after injection ranged from 0.3 to 20

  16. Macrophage ABCA5 deficiency influences cellular cholesterol efflux and increases susceptibility to atherosclerosis in female LDLr knockout mice

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Dan, E-mail: y.dan@lacdr.leidenuniv.nl [Division of Biopharmaceutics, LACDR, Leiden University (Netherlands); Meurs, Illiana [Division of Biopharmaceutics, LACDR, Leiden University (Netherlands); Ohigashi, Megumi [Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University (Japan); Calpe-Berdiel, Laura; Habets, Kim L.L.; Zhao, Ying [Division of Biopharmaceutics, LACDR, Leiden University (Netherlands); Kubo, Yoshiyuki [Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University (Japan); Yamaguchi, Akihito [Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University (Japan); Van Berkel, Theo J.C. [Division of Biopharmaceutics, LACDR, Leiden University (Netherlands); Nishi, Tsuyoshi [Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University (Japan); Van Eck, Miranda [Division of Biopharmaceutics, LACDR, Leiden University (Netherlands)

    2010-05-07

    Objectives: To determine the role of macrophage ATP-binding cassette transporter A5 (ABCA5) in cellular cholesterol homeostasis and atherosclerotic lesion development. Methods and results: Chimeras with dysfunctional macrophage ABCA5 (ABCA5{sup -M/-M}) were generated by transplantation of bone marrow from ABCA5 knockout (ABCA5{sup -/-}) mice into irradiated LDLr{sup -/-} mice. In vitro, bone marrow-derived macrophages from ABCA5{sup -M/-M} chimeras exhibited a 29% (P < 0.001) decrease in cholesterol efflux to HDL, whereas a 21% (P = 0.07) increase in cholesterol efflux to apoA-I was observed. Interestingly, expression of ABCA1, but not ABCG1, was up-regulated in absence of functional ABCA5 in macrophages. To induce atherosclerosis, the transplanted LDLr{sup -/-} mice were fed a high-cholesterol Western-type diet (WTD) for 6, 10, or 18 weeks, allowing analysis of effects on initial as well as advanced lesion development. Atherosclerosis development was not affected in male ABCA5{sup -M/-M} chimeras after 6, 10, and 18 weeks WTD feeding. However, female ABCA5{sup -M/-M} chimeras did develop significantly (P < 0.05) larger aortic root lesions as compared with female controls after 6 and 10 weeks WTD feeding. Conclusions: ABCA5 influences macrophage cholesterol efflux, and selective disruption of ABCA5 in macrophages leads to increased atherosclerotic lesion development in female LDLr{sup -/-} mice.

  17. [An analysis of chimeric mice obtained by the injection of the inner cell mass into the blastocyst].

    Science.gov (United States)

    Mitalipov, Sh M; Fedorov, L M; Strel'chenko, N S

    1993-01-01

    Mouse chimeras were produced using injections of ICM cells into blastocysts. Chimerism of resulting animals was determined by their coat color and spectrum of glucosephosphate isomerase isoenzymes. The use of modifications of the injection method for solving different genetic and embryological problems is discussed.

  18. Domain Modeling: NP_115814.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available dimethyl-lysine and in chimera with histone H3.3(28-34) p1oyxa_ chr6/NP_115814.1/NP_115814.1_apo_231-565.pd...NP_115814.1 chr6 Crystal structure of the 3-MBT repeats from human L3MBTL1 bound to

  19. Developmental competence of porcine chimeric embryos produced by aggregation

    DEFF Research Database (Denmark)

    Li, Juan; Jakobsen, Jannik E.; Xiong, Qiang

    2015-01-01

    The purpose of our study was to compare the developmental competence and blastomere allocation of porcine chimeric embryos formed by micro-well aggregation. Chimeras were created by aggregating either two blastomeres originating from 2-cell embryos or two whole embryos, where embryos were produced...

  20. DNA meets synthetic polymers—highly versatile hybrid materials

    NARCIS (Netherlands)

    Alemdaroglu, Fikri E.; Herrmann, Andreas

    2007-01-01

    The combination of synthetic polymers and DNA has provided biologists, chemists and materials scientists with a fascinating new hybrid material. The challenges in preparing these molecular chimeras were overcome by different synthetic strategies that rely on coupling the nucleic acid moiety and the

  1. Characterisation of the zebrafish serotonin transporter functionally links TM10 to the ligand binding site

    DEFF Research Database (Denmark)

    Severinsen, Kasper; Müller, Heidi Kaastrup; Wiborg, Ove

    2008-01-01

    and [(3)H]-escitalopram binding in transiently transfected human embryonic kidney cells; HEK-293-MSR. Residues responsible for altered affinities inhibitors were pinpointed by generating cross-species chimeras and subsequent point mutations by site directed mutagenesis. drSERT has a higher affinity...

  2. Domain Modeling: NP_057205.2 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available dle chimera channel) in association with beta subunit p2r9rh_ chr1/NP_057205.2/NP_057205.2_holo_17-345.pdb psi-blast 288G,291L,294T PGW 0 ... ...NP_057205.2 chr1 Shaker family voltage dependent potassium channel (kv1.2-kv2.1 pad

  3. Fulminant lymphocytic choriomeningitis virus-induced inflammation of the CNS involves a cytokine-chemokine-cytokine-chemokine cascade

    DEFF Research Database (Denmark)

    Christensen, Jeanette Erbo; Simonsen, Stine; Fenger, Christina;

    2009-01-01

    the expression of CXCL10 in the CNS of LCMV-infected mice. Using mice deficient in type I IFN receptor, type II IFN receptor, or type II IFN, as well as bone marrow chimeras expressing CXCL10 only in resident cells or only in bone marrow-derived cells, we analyzed the up-stream regulation as well as the cellular...

  4. Helper plasmid cloning in Streptococcus sanguis: cloning of a tetracycline resistance determinant from the Streptococcus mutans chromosome.

    Science.gov (United States)

    Tobian, J A; Macrina, F L

    1982-10-01

    A model system for testing the helper plasmid cloning system of Gryczan et al. (Mol. Gen. Genet. 177:459-467, 1980) was devised for the Streptococcus sanguis (Challis) host-vector system. In this system, linearized pVA736 plasmid efficiently transformed an S. sanguis (Challis) host containing a homologous plasmid, pVA380-1, but did not transform a plasmidless host or a host containing a nonhomologous plasmid, pVA380. In addition, whereas monomeric circular pVA736 transformed a plasmidless host with two-hit kinetics, it transformed a pVA380-1-containing host with one-hit kinetics. This helper plasmid cloning system was used to isolate two HindIII fragments (5.0 megadaltons [Mdal] and 1.9 Mdal in size) from the chromosome of Streptococcus mutans V825 which conferred high-level tetracycline resistance. One tetracycline-resistant clone was examined and found to contain three plasmids which were sized and designated pVA868 (9.0 Mdal), pVA869 (9.5 Mdal), and pVA870 (9.8 Mdal). Results of Southern blot hybridization and restriction endonuclease digestion confirmed that all three chimeras were composed of two HindIII fragments of the S. mutans V825 chromosome, as well as a large portion, varying in size for each chimera, of the 2.8 Mdal cloning vector, pVA380-1. Incompatibility observed between pVA380-1 and each of the chimeras indicated that replication of the chimeras was governed by the pVA380-1 replicative origin. Southern blotting experiments revealed that the chimeras hybridized to Tn916, providing the first evidence that transposon-related genes of enteric streptococcal origin are disseminated among oral streptococci.

  5. C-terminal tail of FGF19 determines its specificity toward Klotho co-receptors.

    Science.gov (United States)

    Wu, Xinle; Lemon, Bryan; Li, XiaoFan; Gupte, Jamila; Weiszmann, Jennifer; Stevens, Jennitte; Hawkins, Nessa; Shen, Wenyan; Lindberg, Richard; Chen, Jin-Long; Tian, Hui; Li, Yang

    2008-11-28

    FGF19 subfamily proteins (FGF19, FGF21, and FGF23) are unique members of fibroblast growth factors (FGFs) that regulate energy, bile acid, glucose, lipid, phosphate, and vitamin D homeostasis in an endocrine fashion. Their activities require the presence of alpha or betaKlotho, two related single-pass transmembrane proteins, as co-receptors in relevant target tissues. We previously showed that FGF19 can bind to both alpha and betaKlotho, whereas FGF21 and FGF23 can bind only to either betaKlotho or alphaKlotho, respectively in vitro. To determine the mechanism regulating the binding and specificity among FGF19 subfamily members to Klotho family proteins, chimeric proteins between FGF19 subfamily members or chimeric proteins between Klotho family members were constructed to probe the interaction between those two families. Our results showed that a chimera of FGF19 with the FGF21 C-terminal tail interacts only with betaKlotho and a chimera with the FGF23 C-terminal tail interacts only with alphaKlotho. FGF signaling assays also reflected the change of specificity we observed for the chimeras. These results identified the C-terminal tail of FGF19 as a region necessary for its recognition of Klotho family proteins. In addition, chimeras between alpha and betaKlotho were also generated to probe the regions in Klotho proteins that are important for signaling by this FGF subfamily. Both FGF23 and FGF21 require intact alpha or betaKlotho for signaling, respectively, whereas FGF19 can signal through a Klotho chimera consisting of the N terminus of alphaKlotho and the C terminus of betaKlotho. Our results provide the first glimpse of the regions that regulate the binding specificity between this unique family of FGFs and their co-receptors.

  6. Analysis of jaagsiekte sheep retrovirus (JSRV) envelope protein domains in transformation.

    Science.gov (United States)

    Hull, Stacey; Lim, Joohyun; Hamil, Alexander; Nitta, Takayuki; Fan, Hung

    2012-12-01

    Jaagsiekte sheep retrovirus (JSRV) is the causative agent of a transmissible lung cancer in sheep. A unique feature is that JSRV envelope protein is also the oncogene for this virus. Previous studies have identified the cytoplasmic tail (CT) of the envelope transmembrane (TM) protein as critical for transformation although other regions of Env have also been implicated. In this study, the roles of other Env regions in transformation were investigated. Chimeras between JSRV Env and the Env of a related non-oncogenic endogenous retrovirus (enJSRV, 5F16) were used. A chimera containing the membrane-spanning region (MSR) of enJSRV inserted into JSRV Env showed substantially reduced transformation, indicating that the MSR plays a role in transformation. Transformation by this chimera was highly dependent on both Ras/Raf/MEK/MAPK and PI3K/Akt/mTOR signaling. A chimera containing the two amino acids in the TM ectodomain that distinguish JSRV and enJSRV showed modestly reduced transformation. Chimeras in the SU protein indicated that the amino terminal region of SU contributes to transformation, while the C-terminal part is not important. To test if Env trimerization is important for transformation, we mutated a leucine-rich sequence in the putative trimerization domain in the ectodomain of TM (Tri-M). This mutant could not transform cells and it did not oligomerize. However, Tri-M could complement a non-transforming mutant CT mutant (Y590F) so oligomerization is not necessary for at least some aspects of transformation. These experiments provide new insight into the regions and residues of JSRV Env protein necessary for oncogenic transformation.

  7. Chimerism in wild adult populations of the broadcast spawning coral Acropora millepora on the Great Barrier Reef.

    Directory of Open Access Journals (Sweden)

    Eneour Puill-Stephan

    Full Text Available BACKGROUND: Chimeras are organisms containing tissues or cells of two or more genetically distinct individuals, and are known to exist in at least nine phyla of protists, plants, and animals. Although widespread and common in marine invertebrates, the extent of chimerism in wild populations of reef corals is unknown. METHODOLOGY/PRINCIPAL FINDINGS: The extent of chimerism was explored within two populations of a common coral, Acropora millepora, on the Great Barrier Reef, Australia, by using up to 12 polymorphic DNA microsatellite loci. At least 2% and 5% of Magnetic Island and Pelorus Island populations of A. millepora, respectively, were found to be chimeras (3% overall, based on conservative estimates. A slightly less conservative estimate indicated that 5% of colonies in each population were chimeras. These values are likely to be vast underestimates of the true extent of chimerism, as our sampling protocol was restricted to a maximum of eight branches per colony, while most colonies consist of hundreds of branches. Genotypes within chimeric corals showed high relatedness, indicating that genetic similarity is a prerequisite for long-term acceptance of non-self genotypes within coral colonies. CONCLUSIONS/SIGNIFICANCE: While some brooding corals have been shown to form genetic chimeras in their early life history stages under experimental conditions, this study provides the first genetic evidence of the occurrence of coral chimeras in the wild and of chimerism in a broadcast spawning species. We hypothesize that chimerism is more widespread in corals than previously thought, and suggest that this has important implications for their resilience, potentially enhancing their capacity to compete for space and respond to stressors such as pathogen infection.

  8. Antiapoptotic effects of erythropoietin in differentiated neuroblastoma SH-SY5Y cells require activation of both the STAT5 and AKT signaling pathways.

    Science.gov (United States)

    Um, Moonkyoung; Lodish, Harvey F

    2006-03-01

    The hematopoietic cytokine erythropoietin (Epo) prevents neuronal death during ischemic events in the brain and in neurodegenerative diseases, presumably through its antiapoptotic effects. To explore the role of different signaling pathways in Epo-mediated antiapoptotic effects in differentiated human neuroblastoma SH-SY5Y cells, we employed a prolactin receptor (PrlR)/erythropoietin receptor (EpoR) chimera system, in which binding of prolactin (Prl) to the extracellular domain activates EpoR signaling in the cytosol. On induction of apoptosis by staurosporine, Prl supports survival of the SH-SY5Y cells expressing the wild-type PrlR/EpoR chimera. In these cells Prl treatment strongly activates the STAT5, AKT, and MAPK signaling pathways and induces weak activation of the p65 NF-kappaB factor. Selective mutation of the eight tyrosine residues of the EpoR cytoplasmic domain results in impaired or absent activation of either STAT5 (mutation of Tyr(343)) or AKT (mutation of Tyr(479)) or both (mutation of all eight tyrosine residues). Most interestingly, Prl treatment does not prevent apoptosis in cells expressing mutant PrlR/EpoR chimeras in which either the STAT5 or the AKT signaling pathways are not activated. In contrast, ERK 1/2 is fully activated by all mutant PrlR/EpoR chimeras, comparable with the level seen with the wild-type PrlR/EpoR chimera, implying that activation of the MAPK signaling pathway per se is not sufficient for antiapoptotic activity. Therefore, the antiapoptotic effects of Epo in neuronal cells require the combinatorial activation of multiple signaling pathways, including STAT5, AKT, and potentially MAPK as well, in a manner similar to that observed in hematopoietic cells.

  9. Reducing the effects of PCR amplification and sequencing artifacts on 16S rRNA-based studies.

    Directory of Open Access Journals (Sweden)

    Patrick D Schloss

    Full Text Available The advent of next generation sequencing has coincided with a growth in interest in using these approaches to better understand the role of the structure and function of the microbial communities in human, animal, and environmental health. Yet, use of next generation sequencing to perform 16S rRNA gene sequence surveys has resulted in considerable controversy surrounding the effects of sequencing errors on downstream analyses. We analyzed 2.7×10(6 reads distributed among 90 identical mock community samples, which were collections of genomic DNA from 21 different species with known 16S rRNA gene sequences; we observed an average error rate of 0.0060. To improve this error rate, we evaluated numerous methods of identifying bad sequence reads, identifying regions within reads of poor quality, and correcting base calls and were able to reduce the overall error rate to 0.0002. Implementation of the PyroNoise algorithm provided the best combination of error rate, sequence length, and number of sequences. Perhaps more problematic than sequencing errors was the presence of chimeras generated during PCR. Because we knew the true sequences within the mock community and the chimeras they could form, we identified 8% of the raw sequence reads as chimeric. After quality filtering the raw sequences and using the Uchime chimera detection program, the overall chimera rate decreased to 1%. The chimeras that could not be detected were largely responsible for the identification of spurious operational taxonomic units (OTUs and genus-level phylotypes. The number of spurious OTUs and phylotypes increased with sequencing effort indicating that comparison of communities should be made using an equal number of sequences. Finally, we applied our improved quality-filtering pipeline to several benchmarking studies and observed that even with our stringent data curation pipeline, biases in the data generation pipeline and batch effects were observed that could potentially

  10. Mapping of the C3b-binding site of CR1 and construction of a (CR1)2-F(ab')2 chimeric complement inhibitor.

    Science.gov (United States)

    Kalli, K R; Hsu, P H; Bartow, T J; Ahearn, J M; Matsumoto, A K; Klickstein, L B; Fearon, D T

    1991-12-01

    CR1/CR2 chimeric receptors in which various short consensus repeats (SCRs) of CR1 were attached to CR2 were transiently expressed on COS cells, and assessed for the binding of polymerized C3b (pC3b) and anti-CR2 by immunofluorescence. Of COS cells expressing chimeras containing SCR 1-4, 1-3, 2-4, 1-2, and 2-3 of the long homologous repeats (LHRs) -B or -C, 96%, 66%, 23%, 0%, and 0%, respectively, bound pC3b. K562 cells were stably transfected with wild-type CR1, deletion mutants of CR1, and the CR1/CR2 chimeras, respectively, and assayed for binding of 125I-pC3b. The dissociation constants (Kd) for pC3b of wild-type CR1 and the LHR-BD and -CD constructs were in the range of 1.0-2.7 nM, and of the CR1/CR2 chimeras containing SCRs 1-4, 1-3, and 2-4 of LHR-B or -C were 1.8-2.4, 6-9, and 22-36 nM, respectively. The factor I-cofactor function of the CR1/CR2 chimeras paralleled the C3b-binding function of the constructs. A CR1/immunoglobulin (Ig) chimeric protein was prepared by fusing SCRs 1-4 of LHR-B to the heavy chains of a murine F(ab')2 anti-nitrophenacetyl (NP) monoclonal antibody. The (CR1)2-F(ab')2 chimera, which retained its specificity for NP, was as effective as soluble, full-length CR1 in binding pC3b, serving as a cofactor for factor I-mediated cleavage of C3b, and inhibiting activation of the alternative pathway, indicating that the bivalent expression of these SCRs reconstitutes the alternative pathway inhibitory function of CR1. The feasibility of creating CR1/Ig chimeras makes possible a new strategy of targeting complement inhibition by the use of Ig fusion partners having particular antigenic specificities.

  11. Solving Set Cover with Pairs Problem using Quantum Annealing

    Science.gov (United States)

    Cao, Yudong; Jiang, Shuxian; Perouli, Debbie; Kais, Sabre

    2016-09-01

    Here we consider using quantum annealing to solve Set Cover with Pairs (SCP), an NP-hard combinatorial optimization problem that plays an important role in networking, computational biology, and biochemistry. We show an explicit construction of Ising Hamiltonians whose ground states encode the solution of SCP instances. We numerically simulate the time-dependent Schrödinger equation in order to test the performance of quantum annealing for random instances and compare with that of simulated annealing. We also discuss explicit embedding strategies for realizing our Hamiltonian construction on the D-wave type restricted Ising Hamiltonian based on Chimera graphs. Our embedding on the Chimera graph preserves the structure of the original SCP instance and in particular, the embedding for general complete bipartite graphs and logical disjunctions may be of broader use than that the specific problem we deal with.

  12. Reducing ulcerogenic potential of biphenyl acetic acid: Design and development of chimeric derivatives with amino acids

    Directory of Open Access Journals (Sweden)

    Suneela Dhaneshwar

    2016-09-01

    Full Text Available In an attempt to minimize the ulcerogenic potential and associated gastro-intestinal toxicity of bioprecursor fenbufen and its active metabolite biphenyl acetic acid, carrier-linked chimeric derivatives of the latter were designed and synthesized using amino acids as the promoities. DCC coupling method was used for the synthesis of these amides. The chimeras were characterized by IR and 1H NMR. Pharmacological investigations were carried out in animal models for analgesic, anti-inflammatory, anti-arthritic and ulcerogenic activities. The chimeras exhibited high gastro-sparing effect; quick onset and longer duration of analgesia; enhanced/prolonged anti-inflammatory activity and better anti-arthritic effect than fenbufen or biphenyl acetic acid. These derivatives could be useful as a chronotherapy for rheumatoid arthritis due to their prolonged analgesic and anti-inflammatory effects.

  13. Allosteric and orthosteric sites in CC chemokine receptor (CCR5), a chimeric receptor approach

    DEFF Research Database (Denmark)

    Thiele, Stefanie; Steen, Anne; Jensen, Pia C;

    2011-01-01

    molecules often act more deeply in an allosteric mode. However, opposed to the well described molecular interaction of allosteric modulators in class C 7-transmembrane helix (7TM) receptors, the interaction in class A, to which the chemokine receptors belong, is more sparsely described. Using the CCR5...... chemokine receptor as a model system, we studied the molecular interaction and conformational interchange required for proper action of various orthosteric chemokines and allosteric small molecules, including the well known CCR5 antagonists TAK-779, SCH-C, and aplaviroc, and four novel CCR5 ago......-allosteric molecules. A chimera was successfully constructed between CCR5 and the closely related CCR2 by transferring all extracellular regions of CCR2 to CCR5, i.e. a Trojan horse that resembles CCR2 extracellularly but signals through a CCR5 transmembrane unit. The chimera bound CCR2 (CCL2 and CCL7), but not CCR5...

  14. Diploidization of cucumber (Cucumis sativus L. haploids by colchicine treatment

    Directory of Open Access Journals (Sweden)

    Vesselina Nikolova

    2014-02-01

    Full Text Available Haploid cucumber plants are totally infertile and do not undergo spontaneous diploidization. The use of haploids depends on the possibility of doubling the chromosome number and the obtaining of stable doubled haploids (DH. Four haploids of different genotypes propagated vegetatively were treated with colchicine in order to obtain DH. The following procedures were used: 1 apical shoot meristem treatment, 2 soaking of shoot explants, 3 placing of shoot explants on medium with colchicine. Plants of the C1 generation were evaluated in respect to morphological and cytological characters and fertility. The best result of 20.9% DH was obtained after repeated treatment of the meristem with colchicine. A large group of chimeras (28.5% was also distinguished as were haploids and tetraploids. DH plants were fertile and gave uniform progeny. Chimeras had a decreased fertility and showed disturbances in meiotic divisions.

  15. EBV-induced human CD8+ NKT cells synergize CD4+NKT cells suppressing EBV-associated tumors upon induction of Th1 bias

    Institute of Scientific and Technical Information of China (English)

    Wei Xiao; Xiaoling Zheng; Xinti Tan; Lang Chen; Tao Xiong; Jie Xiong; Youxin Jin; Jinquan Tan; Yuling He; Li Li; Rui Zhou; Ruijing Xiao; Yujuan Wang; Xiang Ji; Mengjun Wu; Lan Wang; Wei Huang

    2011-01-01

    @@ The authors inadvertently published histograms in the fourth panel to the right in both rows of Figure 4c that were actually the data of CD8+NKT cells from EBV-exposed CD8+ NKT cell-transferred, or EBV-exposed CD4 + and CD8 + NKT-transferred hu-thym-SCID chimeras.The corrected figure included here contains the histograms that correctly represent the data of T ceils from EBV-exposed CD4+ and CD8+NKT-transferred hu-thym-SCID chimeras.Since the fourth panels to the right in both rows of Figure 4c show the cellular proliferation using the CFSE labeling technique, the histogram substitutions do not alter the conclusions that were drawn from the original data.The authors would like to apologize for their mistake.

  16. A chimeric path to neuronal synchronization

    Science.gov (United States)

    Essaki Arumugam, Easwara Moorthy; Spano, Mark L.

    2015-01-01

    Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an "all or none" phenomenon, but can pass through an intermediate stage (chimera).

  17. A chimeric path to neuronal synchronization

    Energy Technology Data Exchange (ETDEWEB)

    Essaki Arumugam, Easwara Moorthy; Spano, Mark L. [School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287-9709 (United States)

    2015-01-15

    Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an “all or none” phenomenon, but can pass through an intermediate stage (chimera)

  18. Effect of long-term culturing on the potential of mouse embryonic stem cells for in vitro and in vivo development

    Energy Technology Data Exchange (ETDEWEB)

    Mitalipov, Sh.M.; Mitalipova, M.M.; Ivanov, V.I.

    1994-11-01

    We performed comparative analysis of in vitro and in vivo pluripotency for two clones of ES-D3 cells subjected to different number of passages after the beginning of subcloning. Both clones of ES cells produced characteristically shaped colonies and embryoid bodies during culturing in suspension. High activity of alkaline phosphatase was demonstrated in ES cells by cytochemical staining. The proportion of aneuploid ES cells increased with the increase in the number of passages, as shown by karyotyping. Experiments on producing chimeric mice using ES cells have shown that clone D3W (passage 17) exceeds clone D3M (passage 42) both in terms of chimera proportion among the offspring and in terms of the extent of coat chimerism (proportion of agouti coat color (ES component) in the coat of chimeras). 26 refs., 4 figs., 3 tabs.

  19. [The effect of the duration of culturing on the pluripotency of mouse embryonic stem (ES) cells in vitro and in vivo].

    Science.gov (United States)

    Mitalipov, Sh M; Mitallipova, M M; Ivanov, V I

    1994-01-01

    A comparative analysis of two clones of mouse embryonic stem cells (ES-D3) that underwent different number of passages was performed to determine their potencies for in vitro and in vivo development. Cells of both clones had similar morphology characteristic of undifferentiated ES cells and were capable of forming embryoid bodies in the suspension cultures. Specific alkaline phosphatase activity of ES cells was revealed by cytochemical staining. Karyotyping showed that the proportion of aneuploid ES cells increases with an increase in the number of passages. The results of experiments on chimera production using ES cells showed that the clone D3W (passage 17) is superior to the clone D3M (passage 42) in terms of both the proportion of chimeras produced and the degree of coat color chimerism in them.

  20. Generation of chimeric rhesus monkeys.

    Science.gov (United States)

    Tachibana, Masahito; Sparman, Michelle; Ramsey, Cathy; Ma, Hong; Lee, Hyo-Sang; Penedo, Maria Cecilia T; Mitalipov, Shoukhrat

    2012-01-20

    Totipotent cells in early embryos are progenitors of all stem cells and are capable of developing into a whole organism, including extraembryonic tissues such as placenta. Pluripotent cells in the inner cell mass (ICM) are the descendants of totipotent cells and can differentiate into any cell type of a body except extraembryonic tissues. The ability to contribute to chimeric animals upon reintroduction into host embryos is the key feature of murine totipotent and pluripotent cells. Here, we demonstrate that rhesus monkey embryonic stem cells (ESCs) and isolated ICMs fail to incorporate into host embryos and develop into chimeras. However, chimeric offspring were produced following aggregation of totipotent cells of the four-cell embryos. These results provide insights into the species-specific nature of primate embryos and suggest that a chimera assay using pluripotent cells may not be feasible.

  1. Critique of optical negative refraction superlensing

    OpenAIRE

    Christou, George; Mias, Christos

    2011-01-01

    Has the ten-year old quest for the optical superlens, based on Veselago's hypothesis of negative refraction, been a chimera? We argue that Pendry's alternative prescription of the silver superlens is nothing more than an application of the natural phenomenon of surface plasmon resonance that occurs in the noble metal films. This phenomenon does not predict the reality of Veselago's negative refractive index materials. We give a simple explanation of how this resonance achieves a field intensi...

  2. The Molecular Mechanism by which PIP2 Opens the Intracellular G-Loop Gate of a Kir3.1 Channel

    OpenAIRE

    Meng, Xuan-Yu; Zhang, Hong-Xing; Logothetis, Diomedes E.; Cui, Meng

    2012-01-01

    Inwardly rectifying potassium (Kir) channels are characterized by a long pore comprised of continuous transmembrane and cytosolic portions. A high-resolution structure of a Kir3.1 chimera revealed the presence of the cytosolic (G-loop) gate captured in the closed or open conformations. Here, we conducted molecular-dynamics simulations of these two channel states in the presence and absence of phosphatidylinositol bisphosphate (PIP2), a phospholipid that is known to gate Kir channels. Simulati...

  3. Generation of cloned and chimeric embryos/offspring using the new methods of animal biotechnology.

    Science.gov (United States)

    Skrzyszowska, Maria; Karasiewicz, Jolanta; Bednarczyk, Marek; Samiec, Marcin; Smorag, Zdzisław; Waś, Bogusław; Guszkiewicz, Andrzej; Korwin-Kossakowski, Maciej; Górniewska, Maria; Szablisty, Ewa; Modliński, Jacek A; Łakota, Paweł; Wawrzyńska, Magdalena; Sechman, Andrzej; Wojtysiak, Dorota; Hrabia, Anna; Mika, Maria; Lisowski, Mirosław; Czekalski, Przemysław; Rzasa, Janusz; Kapkowska, Ewa

    2006-01-01

    The article summarizes results of studies concerning: 1/ qualitative evaluation of pig nuclear donor cells to somatic cell cloning, 2/ developmental potency of sheep somatic cells to create chimera, 3/ efficient production of chicken chimera. The quality of nuclear donor cells is one of the most important factors to determine the efficiency of somatic cell cloning. Morphological criteria commonly used for qualitative evaluation of somatic cells may be insufficient for practical application in the cloning. Therefore, different types of somatic cells being the source of genomic DNA in the cloning procedure were analyzed on apoptosis with the use of live-DNA or plasma membrane fluorescent markers. It has been found that morphological criteria are a sufficient selection factor for qualitative evaluation of nuclear donor cells to somatic cell cloning. Developmental potencies of sheep somatic cells in embryos and chimeric animals were studied using blastocyst complementation test. Fetal fibroblasts stained with vital fluorescent dye and microsurgically placed in morulae or blastocysts were later identified in embryos cultured in vitro. Transfer of Polish merino blastocysts harbouring Heatherhead fibroblasts to recipient ewes brought about normal births at term. Newly-born animals were of merino appearance with dark patches on their noses, near the mouth and on their clovens. This overt chimerism shows that fetal fibroblasts introduced to sheep morulae/blastocysts revealed full developmental plasticity. To achieve the efficient production of chicken chimeras, the blastodermal cells from embryos of the donor breeds, (Green-legged Partridgelike breed or GPxAraucana) were transferred into the embryos of the recipient breed (White Leghorn), and the effect of chimerism on the selected reproductive and physiological traits of recipients was examined. Using the model which allowed identification of the chimerism at many loci, it has been found that 93.9% of the examined birds

  4. The perfect host: a mouse host embryo facilitating more efficient germ line transmission of genetically modified embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Robert A Taft

    Full Text Available There is a continual need to improve efficiency in creating precise genetic modifications in mice using embryonic stem cells (ESCs. We describe a novel approach resulting in 100% germline transmission from competent injected ESCs. We developed an F1 mouse host embryo (Perfect Host, PH that selectively ablates its own germ cells via tissue-specific induction of diphtheria toxin. This approach allows competent microinjected ESCs to fully dominate the germline, eliminating competition for this critical niche in the developing and adult animal. This is in contrast to conventional methods, where competition from host germ cells results in offspring derived from host cells and ESCs, necessitating extensive breeding of chimeras and genotyping to identify germline. The germline transmission process is also complicated by variability in the actual number of ESCs that colonize the germline niche and the proportion that are germline competent. To validate the PH approach we used ESC lines derived from 129 F1, BALB/cByJ, and BTBR backgrounds as well as an iPS line. Resulting chimeric males produced 194 offspring, all paternally derived from the introduced stem cells, with no offspring being derived from the host genome. We further tested this approach using eleven genetically modified C57BL/6N ESC lines (International Knockout Mouse Consortium. ESC germline transmission was observed in 9/11 (82% lines using PH blastocysts, compared to 6/11 (55% when conventional host blastocysts were used. Furthermore, less than 35% (83/240 of mice born in the first litters from conventional chimeras were confirmed to be of ESC-origin. By comparison, 100% (137/137 of the first litter offspring of PH chimeras were confirmed as ESC-derived. Together, these data demonstrate that the PH approach increases the probability of germline transmission and speeds the generation of ESC derived animals from chimeras. Collectively, this approach reduces the time and costs inherent in the

  5. Domain Modeling: NP_006161.2 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_006161.2 chr12 Structure of an acetylated Rsc4 tandem bromodomain Histone Chimer...a p2r10a_ chr12/NP_006161.2/NP_006161.2_holo_608-774.pdb swppa 646L,647N,650S,651K,652G,655S,656E,713N,727L,728S,731K EDO 0 ...

  6. Developmental potential and behavior of tetraploid cells in the mouse embryo.

    Science.gov (United States)

    Eakin, Guy S; Hadjantonakis, Anna-Katerina; Papaioannou, Virginia E; Behringer, Richard R

    2005-12-01

    Tetraploid (4n) mouse embryos die at variable developmental stages. By examining 4n embryos from F2 hybrid and outbred mice, we show that 4n developmental potential is influenced by genetic background. The imprinted inactivation of an X chromosome-linked eGFP transgene in extraembryonic tissues occurred correctly in 4n embryos. A decrease of the cleavage rate in 4n preimplantation embryos compared to diploid (2n) embryos was revealed by real-time imaging, using a histone H2b:eGFP reporter. It has previously been known that mouse chimeras produced by the combination of diploid (2n) embryos with embryonic stem (ES) cells result in mixtures of the two components in epiblast-derived tissues. In contrast, the use of 4n host embryos with ES cells restricts 4n cells from the embryonic regions of chimeras, resulting in mice that are believed to be completely ES-derived. Using H2b:eGFP transgenic mice and ES cells, the behavior of 4n cells was determined at single cell resolution in 4n:2n injection and aggregation chimeras. We found a significant contribution of 4n cells to the embryonic ectoderm at gastrulation in every chimera analyzed. We show that the transition of the embryonic regions from a chimeric tissue to a predominantly 2n tissue occurs after gastrulation and that tetraploid cells may persist to midgestation. These findings suggest that the results of previously published tetraploid complementation assays may be influenced by the presence of tetraploid cells in the otherwise diploid embryonic regions.

  7. [Polymorphism of 11 non-CODIS STRs in a population sample of ethnic minority of Polish Tatars residing in northeastern Poland].

    Science.gov (United States)

    Pepiński, Witold; Niemcunowicz-Janica, Anna; Skawrońska, Małgorzata; Aleksandrowicz-Bukin, Maria

    2009-01-01

    Population genetic data for 11 STRs included in the Humantype Chimera kit were obtained by multiplex PCR and subsequent automated fluorescent detection (ABI 310) from a sample of 125 unrelated individuals of ethnic minority of Polish Tatars residing in Podlasie Region (NE Poland). The genotype distributions conformed to HWE for all the analyzed loci except D2S1360 and D21S2055. The highly polymorphic systems exhibit high informativeness and are a potential extension to CODIS loci.

  8. Manipulation of Nf-KappaB Activity in the Macrophage Lineage as a Novel Therapeutic Approach

    Science.gov (United States)

    2008-05-01

    problem. Thus, therapies that would halt invasion and metastasis are desperately needed. It is increasingly clear that the biological behavior of lung...F.E., Cardwell, N., Nanney, L., Kerr, L.D. (2000b) RAG2-/-, IkB-a-/- chimeras display a psoriasis -like skin disease. Journal of Investigative...inhibitor was sufficient to reduce IKK activity and thereby block NF-B activation in the lungs. To examine the impact of BMS-345541 therapy on the dis

  9. Manipulation of NF-KappaBetta Activity in the Macrophage Lineage as a Novel Therapeutic Approach

    Science.gov (United States)

    2007-05-01

    understand- ing of critical cell types and biological pathways that regulate in- nate immunity in the lungs could be useful in designing therapies to...Yull, F.E., Cardwell, N., Nanney, L., Kerr, L.D. (2000b) RAG2-/-, IkB-a-/- chimeras display a psoriasis -like skin disease. Journal of Investigative...B pathway in epithelial cells as an important target for therapies designed to modulate inflammation- induced tissue injury. In humans, evidence

  10. Loss of bone marrow adrenergic beta 1 and 2 receptors modifies transcriptional networks, reduces circulating inflammatory factors, and regulates blood pressure.

    Science.gov (United States)

    Ahmari, Niousha; Schmidt, Jordan T; Krane, Gregory A; Malphurs, Wendi; Cunningham, Bruce E; Owen, Jennifer L; Martyniuk, Christopher J; Zubcevic, Jasenka

    2016-07-01

    Hypertension (HTN) is a prevalent condition with complex etiology and pathophysiology. Evidence exists of significant communication between the nervous system and the immune system (IS), and there appears to be a direct role for inflammatory bone marrow (BM) cells in the pathophysiology of hypertension. However, the molecular and neural mechanisms underlying this interaction have not been characterized. Here, we transplanted whole BM cells from the beta 1 and 2 adrenergic receptor (AdrB1(tm1Bkk)AdrB2(tm1Bkk)/J) knockout (KO) mice into near lethally irradiated C57BL/6J mice to generate a BM AdrB1.B2 KO chimera. This allowed us to evaluate the role of the BM beta 1 and beta 2 adrenergic receptors in mediating BM IS homeostasis and regulating blood pressure (BP) in an otherwise intact physiological setting. Fluorescence-activated cell sorting demonstrated that a decrease in systolic and mean BP in the AdrB1.B2 KO chimera is associated with a decrease in circulating inflammatory T cells, macrophage/monocytes, and neutrophils. Transcriptomics in the BM identified 7,419 differentially expressed transcripts between the C57 and AdrB1.B2 KO chimera. Pathway analysis revealed differentially expressed transcripts related to several cell processes in the BM of C57 compared with AdrB1.B2 KO chimera, including processes related to immunity (e.g., T-cell activation, T-cell recruitment, cytokine production, leukocyte migration and function), the cardiovascular system (e.g., blood vessel development, peripheral nerve blood flow), and the brain (e.g., central nervous system development, neurite development) among others. This study generates new insight into the molecular events that underlie the interaction between the sympathetic drive and IS in modulation of BP.

  11. Platelet-Derived Growth Factor B-Chain of Hematopoietic Origin Is Not Necessary for Granulation Tissue Formation and Its Absence Enhances Vascularization

    OpenAIRE

    Buetow, Bernard S; Crosby, Jeffrey R.; Wolfgang E Kaminski; Ramachandran, Ravi K.; Lindahl, Per; Martin, Paul; Betsholtz, Christer; Seifert, Ronald A.; Raines, Elaine W.; Bowen-Pope, Daniel F.

    2001-01-01

    The hypothesis that wound repair is augmented by delivery of platelet-derived growth factor (PDGF) from platelets and macrophages is an attractive extrapolation from the known activities of PDGF in cell culture and in vivo. To test this hypothesis in mice, we prepared hematopoietic chimeras, in which the hematopoietic system of a normal adult mouse was replaced by the hematopoietic system of a PDGF B-chain −/− or +/+ donor. We initiated local granulation tissue formation either by implanting ...

  12. Towards Partial Compositeness on the Lattice: Baryons with Fermions in Multiple Representations

    CERN Document Server

    DeGrand, Thomas A; Jay, William I; Neil, Ethan T; Shamir, Yigal; Svetitsky, Benjamin

    2016-01-01

    We describe our recent lattice study of SU(4) gauge theory with fermions in the fundamental and sextet representations. In this theory, a new type of baryon consists of quarks in both representations. The spectrum of these "chimera baryons" has a straightforward interpretation in terms of a non-relativistic quark model based on SU(4). Our results are particularly relevant to composite Higgs models in which the top quark is partially composite.

  13. Experiment list: SRX760591 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available P-Seq source_name=Lung macrophages with CD45.1 mark || strain=C57BL/6 || tissue=Lung || cell type=Lung mac...rophages with CD45.1 mark || chip antibody=none (whole cell extract) http://dbarchi...logy, Lackie and Dow, 3rd ed.) 14651751,98.1,12.7,301 GSM1546006: MC f16 Chimera Lung WCE; Mus musculus; ChI

  14. Production and evaluation of a recombinant chimeric vaccine against clostridium botulinum neurotoxin types C and D.

    Science.gov (United States)

    Gil, Luciana A F; da Cunha, Carlos Eduardo P; Moreira, Gustavo M S G; Salvarani, Felipe M; Assis, Ronnie A; Lobato, Francisco Carlos F; Mendonça, Marcelo; Dellagostin, Odir A; Conceição, Fabricio R

    2013-01-01

    Bovine botulism is a fatal disease that is caused by botulinum neurotoxins (BoNTs) produced by Clostridium botulinum serotypes C and D and that causes great economic losses, with nearly 100% lethality during outbreaks. It has also been considered a potential source of human food-borne illness in many countries. Vaccination has been reported to be the most effective way to control bovine botulism. However, the commercially available toxoid-based vaccines are difficult and hazardous to produce. Neutralizing antibodies targeted against the C-terminal fragment of the BoNT heavy chain (HC) are known to confer efficient protection against lethal doses of BoNTs. In this study, a novel recombinant chimera, consisting of Escherichia coli heat-labile enterotoxin B subunit (LTB), a strong adjuvant of the humoral immune response, fused to the HC of BoNT serotypes C and D, was produced in E. coli. Mice vaccinated with the chimera containing LTB and an equivalent molar ratio of the chimera without LTB plus aluminum hydroxide (Al(OH)3) developed 2 IU/mL of antitoxins for both serotypes. Guinea pigs immunized with the recombinant chimera with LTB plus Al(OH)3 developed a protective immune response against both BoNT/C (5 IU/mL) and BoNT/D (10 IU/mL), as determined by a mouse neutralization bioassay with pooled sera. The results achieved with guinea pig sera fulfilled the requirements of commercial vaccines for prevention of botulism, as determined by the Brazilian Ministry of Agriculture, Livestock and Food, Supply. The presence of LTB was essential for the development of a strong humoral immune response, as it acted in synergism with Al(OH)3. Thus, the vaccine described in this study is a strong candidate for the control of botulism in cattle.

  15. Production and evaluation of a recombinant chimeric vaccine against clostridium botulinum neurotoxin types C and D.

    Directory of Open Access Journals (Sweden)

    Luciana A F Gil

    Full Text Available Bovine botulism is a fatal disease that is caused by botulinum neurotoxins (BoNTs produced by Clostridium botulinum serotypes C and D and that causes great economic losses, with nearly 100% lethality during outbreaks. It has also been considered a potential source of human food-borne illness in many countries. Vaccination has been reported to be the most effective way to control bovine botulism. However, the commercially available toxoid-based vaccines are difficult and hazardous to produce. Neutralizing antibodies targeted against the C-terminal fragment of the BoNT heavy chain (HC are known to confer efficient protection against lethal doses of BoNTs. In this study, a novel recombinant chimera, consisting of Escherichia coli heat-labile enterotoxin B subunit (LTB, a strong adjuvant of the humoral immune response, fused to the HC of BoNT serotypes C and D, was produced in E. coli. Mice vaccinated with the chimera containing LTB and an equivalent molar ratio of the chimera without LTB plus aluminum hydroxide (Al(OH3 developed 2 IU/mL of antitoxins for both serotypes. Guinea pigs immunized with the recombinant chimera with LTB plus Al(OH3 developed a protective immune response against both BoNT/C (5 IU/mL and BoNT/D (10 IU/mL, as determined by a mouse neutralization bioassay with pooled sera. The results achieved with guinea pig sera fulfilled the requirements of commercial vaccines for prevention of botulism, as determined by the Brazilian Ministry of Agriculture, Livestock and Food, Supply. The presence of LTB was essential for the development of a strong humoral immune response, as it acted in synergism with Al(OH3. Thus, the vaccine described in this study is a strong candidate for the control of botulism in cattle.

  16. Domain-swapping of mesophilic xylanase with hyper-thermophilic glucanase

    Directory of Open Access Journals (Sweden)

    Liu Liangwei

    2012-06-01

    Full Text Available Abstract Background Domain fusion is limited at enzyme one terminus. The issue was explored by swapping a mesophilic Aspergillus niger GH11 xylanase (Xyn with a hyper-thermophilic Thermotoga maritima glucanase (Glu to construct two chimeras, Xyn-Glu and Glu-Xyn, with an intention to create thermostable xylanase containing glucanase activity. Results When expressed in E. coli BL21(DE3, the two chimeras exhibited bi-functional activities of xylanase and glucanase. The Xyn-Glu Xyn moiety had optimal reaction temperature (Topt at 50 °C and thermal in-activation half-life (t1/2 at 50 °C for 47.6 min, compared to 47 °C and 17.6 min for the Xyn. The Glu-Xyn Xyn moiety had equivalent Topt to and shorter t1/2 (5.2 min than the Xyn. Both chimera Glu moieties were more thermostable than the Glu, and the three enzyme Topt values were higher than 96 °C. The Glu-Xyn Glu moiety optimal pH was 5.8, compared to 3.8 for the Xyn-Glu Glu moiety and the Glu. Both chimera two moieties cooperated with each other in degrading substrates. Conclusions Domain-swapping created different effects on each moiety properties. Fusing the Glu domain at C-terminus increased the xylanase thermostability, but fusing the Glu domain at N-terminus decreased the xylanase thermostability. Fusing the Xyn domain at either terminus increased the glucanase thermostability, and fusing the Xyn domain at C-terminus shifted the glucanase pH property 2 units higher towards alkaline environments. Fusing a domain at C-terminus contributes more to enzyme catalytic activity; whereas, fusing a bigger domain at N-terminus disturbs enzyme substrate binding affinity.

  17. Alteration of substrate specificities of thermophilic α/β hydrolases through domain swapping and domain interface optimization

    Institute of Scientific and Technical Information of China (English)

    Xiaoli Zhou; Honglei Wang; Yuhang Zhang; Le Gao; Yan Feng

    2012-01-01

    Protein domain swapping is an efficient way in protein functional evolution in vivo and also has been proved to be an effective strategy to modify the function of the multidomain proteins in vitro.To explore the potentials of domain swapping for alteration of the enzyme substrate specificities and the structure-function relationship of the homologous proteins,here we constructed two chimeras from a pair of thermophilic members of the α/β hydrolase superfamily by grafting their functional domains to the conserved α/β hydrolase fold domain:a carboxylesterase from Archaeoglobus fulgidus (AFEST) and an acylpeptide hydrolase from Aeropyrum pernix K1 (apAPH) and explored their activities on hydrolyze p-nitrophenyl esters (pNP) with different acyl chain lengths.We took two approaches to reduce the crossover disruptions when creating the chimeras:chose the residue which involved in the least contacts as the splicing site and optimized the newly formed domain interfaces of the chimeras by sitedirected mutations.Characterizations of AAM7 and PAR showed that these chimeras inherited the thermophilic property of both parents.In the aspect of substrate specificity,AAM7 and PAR showed highest activity towards short chain length substrate pNPC4 and middle chain length substrate pNPC8,similar to parent AFEST and apAPH,respectively.These results suggested that the substrate-binding domain is the dominant factor on enzyme substrate specificity,and the optimization of the newly formed domain interface is an important guarantee for successful domain swapping of proteins with low-sequence homology.

  18. Experiment list: SRX760612 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available and Dow, 3rd ed.) 10245893,97.8,12.0,2412 GSM1546027: MC h6 Chimera Spleen2 K27Ac; Mus musculus; ChIP-Seq source_name=Spleen red pul...ue=Lung || cell type=Spleen red pulp macrophages with CD45.1 mark || chip antibody=anti-H3K27ac || chip anti

  19. Experiment list: SRX760596 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ssue=Spleen || cell type=Spleen red pulp macrophages with CD45.1 mark || chip antibody=anti-H3K4me2 || chip ... source_name=Spleen red pulp macrophages with CD45.1 mark || strain=C57BL/6 || ti... and Dow, 3rd ed.) 14456016,93.2,21.5,28285 GSM1546011: MC f05 Chimera Spleen1 K4Me2; Mus musculus; ChIP-Seq

  20. Experiment list: SRX760610 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available and Dow, 3rd ed.) 9174180,98.1,11.4,125 GSM1546025: MC h4 Chimera Spleen2 K4Me1; Mus musculus; ChIP-Seq source_name=Spleen red pulp...=Lung || cell type=Spleen red pulp macrophages with CD45.1 mark || chip antibody=anti-H3K4me1 http://dbarchi

  1. Experiment list: SRX760597 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available sue=Spleen || cell type=Spleen red pulp macrophages with CD45.1 mark || chip antibody=anti-H3K27ac || chip a... and Dow, 3rd ed.) 12890847,97.8,11.3,4235 GSM1546012: MC f06 Chimera Spleen1 K27Ac; Mus musculus; ChIP-Seq ...source_name=Spleen red pulp macrophages with CD45.1 mark || strain=C57BL/6 || tis

  2. Experiment list: SRX760595 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available and Dow, 3rd ed.) 9322532,98.2,10.3,119 GSM1546010: MC f04 Chimera Spleen1 K4Me1; Mus musculus; ChIP-Seq source_name=Spleen red pulp...e=Spleen || cell type=Spleen red pulp macrophages with CD45.1 mark || chip antibody=anti-H3K4me1 http://dbar

  3. Experiment list: SRX760611 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available sue=Lung || cell type=Spleen red pulp macrophages with CD45.1 mark || chip antibody=anti-H3K4me2 || chip ant... and Dow, 3rd ed.) 10685327,94.7,12.3,21158 GSM1546026: MC h5 Chimera Spleen2 K4Me2; Mus musculus; ChIP-Seq ...source_name=Spleen red pulp macrophages with CD45.1 mark || strain=C57BL/6 || tis

  4. Bone marrow-derived versus parenchymal sources of inducible nitric oxide synthase in experimental autoimmune encephalomyelitis

    DEFF Research Database (Denmark)

    Zehntner, Simone P; Bourbonniere, Lyne; Hassan-Zahraee, Mina;

    2004-01-01

    . These discrepancies may reflect balance between immunoregulatory and neurocytopathologic roles for NO. We investigated selective effects of bone marrow-derived versus CNS parenchymal sources of iNOS in EAE in chimeric mice. Chimeras that selectively expressed or ablated iNOS in leukocytes both showed significant...... delay in disease onset, with no difference in disease severity. We conclude that bone marrow-derived and CNS parenchymal sources of iNOS-derived NO both play a regulatory role in EAE....

  5. 2035 Biodeterrence: Problems and Promises for Biodefense

    Science.gov (United States)

    2010-02-17

    also stated that the goal of their "chimera" viruses was to insert genes from one virus to another to create an even more lethal virus. Alibek...modified organisms one need only look to macro bio-agriculture companies like Monsanto , who has used genetic modification widely in agriculture to...example highlights the fact that genetic modification is already a part of everyone’s lives. Further, genetically modified material can be patented , which

  6. Biology and maintenance of Callithrix J. (common marmoset) as a model for biomedical research. Biologia e allevamento di Callithrix j. (common marmoset) quale modello per ricerche biomediche

    Energy Technology Data Exchange (ETDEWEB)

    Monaco, V.

    1983-01-01

    Marmosets, because of their small size, breeding capabilities in captivity and physiological features are proposed as experimental subjects for current scientific demands in immunologic, zoologic, ethologic, pharmacologic and toxicologic studies. The female normally produced twin litters with the complete immunologic tolerance, thus offering opportunities for researches on biologic chimeras and organ transplantations. This report briefly describes the maintenance features in captivity of a colony of marmosets established at Casaccia Nuclear Research Center in 1966. 9 refs.

  7. Accessory Genes Confer a High Replication Rate to Virulent Feline Immunodeficiency Virus

    OpenAIRE

    Troyer, Ryan M.; Thompson, Jesse; Elder, John H.; VandeWoude, Sue

    2013-01-01

    Feline immunodeficiency virus (FIV) is a lentivirus that causes AIDS in domestic cats, similar to human immunodeficiency virus (HIV)/AIDS in humans. The FIV accessory protein Vif abrogates the inhibition of infection by cat APOBEC3 restriction factors. FIV also encodes a multifunctional OrfA accessory protein that has characteristics similar to HIV Tat, Vpu, Vpr, and Nef. To examine the role of vif and orfA accessory genes in FIV replication and pathogenicity, we generated chimeras between tw...

  8. Somatic sex identity is cell-autonomous in the chicken

    OpenAIRE

    D. Zhao; McBride, D; Nandi, S; McQueen, HA; McGrew, MJ; Hocking, PM; Lewis, PD; Sang, HM; Clinton, M

    2010-01-01

    In the mammalian model of sex determination, embryos are considered to be sexually indifferent until the transient action of a sex-determining gene initiates gonadal differentiation. Although this model is thought to apply to all vertebrates, this has yet to be established. We have examined three lateral gynandromorph chickens with the aim of investigating the nature of the sex-determining mechanism in birds. These studies demonstrated that gynandromorph birds are genuine male:female chimeras...

  9. Progress and prospects: techniques for site-directed mutagenesis in animal models

    OpenAIRE

    Yan, Z.; Sun, X.; Engelhardt, JF

    2009-01-01

    In the past 2 years, new gene-targeting approaches using adeno-associated virus and designer zinc-finger nucleases have been successfully applied to the production of genetically modified ferrets, pigs, mice and zebrafish. Gene targeting using these tools has been combined with somatic cell nuclear transfer and germ cell transplantation to generate gene-targeted animal models. These new technical advances, which do not require the generation of embryonic stem cell-derived chimeras, will great...

  10. Embryonic origin and fate of chondroid tissue and secondary cartilages in the avian skull

    OpenAIRE

    Lengelé, Benoît; Schowing, J.; Dhem, Antoine

    1996-01-01

    BACKGROUND: Chondroid tissue is an intermediate calcified tissue, mainly involved in desmocranial morphogenesis. Often associated with secondary cartilages, it remained of unprecise embryonic origin. METHODS: The latter was studied by performing isotopic isochronic grafts of quail encephalon onto 30 chick embryos. The so-obtained chimeras were sacrificed at the 9th, 12th, and 14th day of incubation. The contribution of graft- and host-derived cells to the histogenesis of chondroid tissue,...

  11. On Peace: Peace as a Means of Statecraft

    Science.gov (United States)

    2009-06-01

    relationship between peace, man, and the state will be examined. Philosophers such as Hobbes, Locke, and Hegel share a common understanding of the natural...contract based on interdependence sustains it.22 In contrast to Kant, Hegel believed that “perpetual peace” is a chimera because relations between...20. Ibid., p. 212. 21. Allen W. Wood, ed., Basic Writings of Kant, New York: Modern Library, 2001, p. 441. 22. Ibid., p. 442. 23. G. W. F. Hegel

  12. Studies on mu and delta opioid receptor selectivity utilizing chimeric and site-mutagenized receptors.

    Science.gov (United States)

    Wang, W W; Shahrestanifar, M; Jin, J; Howells, R D

    1995-01-01

    Opioid receptors are members of the guanine nucleotide binding protein (G protein)-coupled receptor family. Three types of opioid receptors have been cloned and characterized and are referred to as the delta, kappa and mu types. Analysis of receptor chimeras and site-directed mutant receptors has provided a great deal of information about functionally important amino acid side chains that constitute the ligand-binding domains and G-protein-coupling domains of G-protein-coupled receptors. We have constructed delta/mu opioid receptor chimeras that were express in human embryonic kidney 293 cells in order to define receptor domains that are responsible for receptor type selectivity. All chimeric receptors and wild-type delta and mu opioid receptors displayed high-affinity binding of etorphine (an agonist), naloxone (an antagonist), and bremazocine (a mixed agonist/antagonist). In contrast, chimeras that lacked the putative first extracellular loop of the mu receptor did not bind the mu-selective peptide [D-Ala2,MePhe4,Gly5-ol]enkephalin (DAMGO). Chimeras that lacked the putative third extracellular loop of the delta receptor did not bind the delta-selective peptide, [D-Ser2,D-Leu5]enkephalin-Thr (DSLET). Point mutations in the putative third extracellular loop of the wild-type delta receptor that converted vicinal arginine residues to glutamine abolished DSLET binding while not affecting bremazocine, etorphine, and naltrindole binding. We conclude that amino acids in the putative first extracellular loop of the mu receptor are critical for high-affinity DAMGO binding and that arginine residues in the putative third extracellular loop of the delta receptor are important for high-affinity DSLET binding. Images Fig. 3 PMID:8618916

  13. Activity of the TonEBP/OREBP transactivation domain varies directly with extracellular NaCl concentration.

    Science.gov (United States)

    Ferraris, Joan D; Williams, Chester K; Persaud, Prita; Zhang, Zheng; Chen, Ye; Burg, Maurice B

    2002-01-22

    Hypertonicity-induced binding of the transcription factor TonEBP/OREBP to its cognate DNA element, ORE/TonE, is associated with increased transcription of several osmotically regulated genes. Previously, it was found that hypertonicity rapidly causes nuclear translocation and phosphorylation of TonEBP/OREBP and, more slowly, increases TonEBP/OREBP abundance. Also, the C terminus of TonEBP/OREBP was found to contain a transactivation domain (TAD). We have now tested for tonicity dependence of the TAD activity of the 983 C-terminal amino acids of TonEBP/OREBP. HepG2 cells were cotransfected with a reporter construct and one of several TAD expression vector constructs. The reporter construct contained GAL4 DNA binding elements, a minimal promoter, and the Photinus luciferase gene. TAD expression vectors generate chimeras comprised of the GAL4 DNA binding domain fused to (i) the 983 C-terminal amino acids of TonEBP/OREBP, (ii) 17 glutamine residues, (iii) the TAD of c-Jun, or (iv) no TAD. All TAD-containing chimeras were functional at normal extracellular osmolality (300 mosmol/kg), but the activity only of the chimera containing the 983 C-terminal amino acids of TonEBP/OREBP varied with extracellular NaCl concentration, decreasing by >80% at 200 mosmol/kg and increasing 8-fold at 500 mosmol/kg. The chimera containing the 983 C-terminal amino acids of TonEBP/OREBP was constitutively localized to the nucleus and showed tonicity-dependent posttranslational modification consistent with phosphorylation. The activity at 500 mosmol/kg was reduced by herbimycin, a tyrosine kinase inhibitor and by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole, a protein kinase CK2 inhibitor. Thus, the 983 C-terminal amino acids of TonEBP/OREBP contain a TAD that is regulated osmotically, apparently by tonicity-dependent phosphorylation.

  14. Introduction to Focus Issue: Patterns of Network Synchronization

    CERN Document Server

    Abrams, Daniel M; Motter, Adilson E

    2016-01-01

    The study of synchronization of coupled systems is currently undergoing a major surge fueled by recent discoveries of new forms of collective dynamics and the development of techniques to characterize a myriad of new patterns of network synchronization. This includes chimera states, phenomena determined by symmetry, remote synchronization, and asymmetry-induced synchronization. This Focus Issue presents a selection of contributions at the forefront of these developments, to which this introduction is intended to offer an up-to-date foundation.

  15. Control of silicification by genetically engineered fusion proteins: Silk–silica binding peptides

    Science.gov (United States)

    Zhou, Shun; Huang, Wenwen; Belton, David J.; Simmons, Leo O.; Perry, Carole C.; Wang, Xiaoqin; Kaplan, David L.

    2014-01-01

    In the present study, an artificial spider silk gene, 6mer, derived from the consensus sequence of Nephila clavipes dragline silk gene, was fused with different silica-binding peptides (SiBPs), A1, A3 and R5, to study the impact of the fusion protein sequence chemistry on silica formation and the ability to generate a silk–silica composite in two different bioinspired silicification systems: solution–solution and solution– solid. Condensed silica nanoscale particles (600–800 nm) were formed in the presence of the recombinant silk and chimeras, which were smaller than those formed by 15mer-SiBP chimeras [1], revealing that the molecular weight of the silk domain correlated to the sizes of the condensed silica particles in the solution system. In addition, the chimeras (6mer-A1/A3/R5) produced smaller condensed silica particles than the control (6mer), revealing that the silica particle size formed in the solution system is controlled by the size of protein assemblies in solution. In the solution–solid interface system, silicification reactions were performed on the surface of films fabricated from the recombinant silk proteins and chimeras and then treated to induce β-sheet formation. A higher density of condensed silica formed on the films containing the lowest β-sheet content while the films with the highest β-sheet content precipitated the lowest density of silica, revealing an inverse correlation between the β-sheet secondary structure and the silica content formed on the films. Intriguingly, the 6mer-A3 showed the highest rate of silica condensation but the lowest density of silica deposition on the films, compared with 6mer-A1 and -R5, revealing antagonistic crosstalk between the silk and the SiBP domains in terms of protein assembly. These findings offer a path forward in the tailoring of biopolymer–silica composites for biomaterial related needs. PMID:25462851

  16. Fungal phosphate transporter serves as a receptor backbone for gibbon ape leukemia virus

    DEFF Research Database (Denmark)

    Pedersen, Lene; van Zeijl, Marja; Johann, Stephen V

    1997-01-01

    Pit1, the receptor for gibbon ape leukemia virus (GALV), is proposed to be an integral membrane protein with five extracellular loops. Chimeras made between Pit1 homologs differing in permissivity for infection and between Pit1 and the related protein Pit2 have shown that the fourth extracellular...... in a functional GALV receptor. Therefore, the presence of a Pit1 loop 4-specific sequence is sufficient to confer receptor function for the mammalian retrovirus GALV on the fungal phosphate transporter Pho-4...

  17. The Multileveled Regulation of the Human Cholinesterase Genes and Their Protein Products

    Science.gov (United States)

    1993-09-30

    present in all members of the Solanua plant family, including Solanin tuberosa (potatoes), and are likely to be present in extremely high and toxic ...and solanine -derived alkaloids 120 33. Conservation of substrate specificity and loss of substrate activation in AChE-BuChE chimera 121 34. Inhibition...for inhibition of the insect enzyme, with particular emphasis on low toxicity to humans. In addition, cholinesterase (ChZ) inhibitors are employed

  18. Generation of Knock-In Pigs Carrying Oct4-tdTomato Reporter through CRISPR/Cas9-Mediated Genome Engineering

    OpenAIRE

    2016-01-01

    The porcine pluripotent cells that can generate germline chimeras have not been developed. The Oct4 promoter-based fluorescent reporter system, which can be used to monitor pluripotency, is an important tool to generate authentic porcine pluripotent cells. In this study, we established a porcine Oct4 reporter system, wherein the endogenous Oct4 promoter directly controls red fluorescent protein (RFP). 2A-tdTomato sequence was inserted to replace the stop codon of the porcine Oct4 gene by homo...

  19. Worldwide Emerging Environmental Issues Affecting the U.S. Military. October 2005 Report

    Science.gov (United States)

    2005-10-01

    waste management aspects; water resources; and genetically modified organisms ( GMO ). Along with Italy, Spain and Greece were also sent final...effects. Noteworthy actions are the UN Food and Agriculture Organization effort in assembling a ’task force’ of health and veterinary specialists...Chimeras and GMOs under Study in January 2004, Bioweapons Are Already Possible to Make, Says New CIA Report and New Lethal Viruses Developed in

  20. In Vivo Differentiation Potential of Epiblast Stem Cells Revealed by Chimeric Embryo Formation

    Directory of Open Access Journals (Sweden)

    Yali Huang

    2012-12-01

    Full Text Available Chimera formation after blastocyst injection or morula aggregation is the principal functional assay of the developmental potential of mouse embryonic stem cells (ESCs. This property, which demonstrates functional equivalence between ESCs and the preimplantation epiblast, is not shared by epiblast stem cell (EpiSC lines. Here, we show that EpiSCs derived either from postimplantation embryos or from ESCs in vitro readily generate chimeras when grafted to postimplantation embryos in whole embryo culture. EpiSC derivatives integrate and differentiate to derivatives of all three embryonic germ layers and primordial germ cells. In contrast, grafted ESCs seldom proliferate in postimplantation embryos, and fail to acquire the identity of their host-derived neighbors. EpiSCs do not incorporate efficiently into embryonic day 8.5 embryos, a stage by which pluripotency has been lost. Thus, chimera formation by EpiSCs requires a permissive environment, the postimplantation epiblast, and demonstrates functional equivalence between this cell type and EpiSCs.

  1. Chimeric RNA/DNA oligonucleotide-based site-specific modification of the tobacco acetolactate syntase gene.

    Science.gov (United States)

    Kochevenko, Andrej; Willmitzer, Lothar

    2003-05-01

    Single amino acid substitutions at either of two crucial positions in acetolactate synthase (ALS) result in a chlorsulfuron-insensitive form of this enzyme and, as a consequence, a herbicide-resistant phenotype. Here, we describe the successful in vivo targeting of endogenous tobacco (Nicotiana tabacum) ALS genes using chimeric RNA/DNA and all-DNA oligonucleotides at two different locations. Similar number of conversion events with two different chimeras indicates the absence of restricting influence of genomic target sequence on the gene repair in tobacco. Chlorsulfuron-resistant plants were regenerated from calli after mesophyll protoplast electroporation or leaf tissue particle bombardment with these specifically constructed chimeras. Sequence analysis and enzyme assays proved the resulting alterations to ALS at both DNA and protein levels. Furthermore, foliar application of chlorsulfuron confirmed the development of resistant phenotypes. Lines with proline-196-alanine, threonine, glutamine, or serine substitutions or with tryptophan-573-leucine substitutions were highly resistant at both cellular and whole plant levels, whereas lines with proline-196-leucine substitutions were less resistant. The stability of these modifications was demonstrated by the continuous growth of calli on chlorsulfuron-containing medium and by the transmission of herbicide resistance to progeny in a Mendelian manner. Ability of haploid state to promote chimera-mediated conversions is discussed.

  2. Expression of Leukemia-Associated Nup98 Fusion Proteins Generates an Aberrant Nuclear Envelope Phenotype.

    Science.gov (United States)

    Fahrenkrog, Birthe; Martinelli, Valérie; Nilles, Nadine; Fruhmann, Gernot; Chatel, Guillaume; Juge, Sabine; Sauder, Ursula; Di Giacomo, Danika; Mecucci, Cristina; Schwaller, Jürg

    2016-01-01

    Chromosomal translocations involving the nucleoporin NUP98 have been described in several hematopoietic malignancies, in particular acute myeloid leukemia (AML). In the resulting chimeric proteins, Nup98's N-terminal region is fused to the C-terminal region of about 30 different partners, including homeodomain (HD) transcription factors. While transcriptional targets of distinct Nup98 chimeras related to immortalization are relatively well described, little is known about other potential cellular effects of these fusion proteins. By comparing the sub-nuclear localization of a large number of Nup98 fusions with HD and non-HD partners throughout the cell cycle we found that while all Nup98 chimeras were nuclear during interphase, only Nup98-HD fusion proteins exhibited a characteristic speckled appearance. During mitosis, only Nup98-HD fusions were concentrated on chromosomes. Despite the difference in localization, all tested Nup98 chimera provoked morphological alterations in the nuclear envelope (NE), in particular affecting the nuclear lamina and the lamina-associated polypeptide 2α (LAP2α). Importantly, such aberrations were not only observed in transiently transfected HeLa cells but also in mouse bone marrow cells immortalized by Nup98 fusions and in cells derived from leukemia patients harboring Nup98 fusions. Our findings unravel Nup98 fusion-associated NE alterations that may contribute to leukemogenesis.

  3. How social evolution theory impacts our understanding of development in the social amoeba Dictyostelium.

    Science.gov (United States)

    Strassmann, Joan E; Queller, David C

    2011-05-01

    Dictyostelium discoideum has been very useful for elucidating principles of development over the last 50 years, but a key attribute means there is a lot to be learned from a very different intellectual tradition: social evolution. Because Dictyostelium arrives at multicellularity by aggregation instead of through a single-cell bottleneck, the multicellular body could be made up of genetically distinct cells. If they are genetically distinct, natural selection will result in conflict over which cells become fertile spores and which become dead stalk cells. Evidence for this conflict includes unequal representation of two genetically different clones in spores of a chimera, the poison-like differentiation inducing factor (DIF) system that appears to involve some cells forcing others to become stalk, and reduced functionality in migrating chimeras. Understanding how selection operates on chimeras of genetically distinct clones is crucial for a comprehensive view of Dictyostelium multicellularity. In nature, Dictyostelium fruiting bodies are often clonal, or nearly so, meaning development will often be very cooperative. Relatedness levels tell us what benefits must be present for sociality to evolve. Therefore it is important to measure relatedness in nature, show that it has an impact on cooperation in the laboratory, and investigate genes that Dictyostelium uses to discriminate between relatives and non-relatives. Clearly, there is a promising future for research at the interface of development and social evolution in this fascinating group.

  4. Activation and routing of membrane-tethered prohormone convertases 1 and 2.

    Science.gov (United States)

    Bruzzaniti, A; Marx, R; Mains, R E

    1999-08-27

    Many peptide hormones and neuropeptides are processed by members of the subtilisin-like family of prohormone convertases (PCs), which are either soluble or integral membrane proteins. PC1 and PC2 are soluble PCs that are primarily localized to large dense core vesicles in neurons and endocrine cells. We examined whether PC1 and PC2 were active when expressed as membrane-tethered proteins, and how tethering to membranes alters the biosynthesis, enzymatic activity, and intracellular routing of these PCs. PC1 and PC2 chimeras were constructed using the transmembrane domain and cytoplasmic domain of the amidating enzyme, peptidylglycine alpha-amidating monooxygenase (PAM). The membrane-tethered PCs were rerouted from large dense core vesicles to the Golgi region. In addition, the chimeras were transiently expressed at the cell surface and rapidly internalized to the Golgi region in a fashion similar to PAM. Membrane-tethered PC1 and PC2 exhibited changes in pro-domain maturation rates, N-glycosylation, and in the pH and calcium optima required for maximal enzymatic activity against a fluorogenic substrate. In addition, the PC chimeras efficiently cleaved endogenous pro-opiomelanocortin to the correct bioactive peptides. The PAM transmembrane domain/cytoplasmic domain also prevented stimulated secretion of pro-opiomelanocortin products in AtT-20 cells.

  5. Taking a lipidation-dependent path toward endolysosomes.

    Science.gov (United States)

    Oeste, Clara L; Martínez-López, Marta; Pérez-Sala, Dolores

    2015-01-01

    We recently reported that the isoprenylation and palmitoylation motif present at the C-terminus of human RhoB protein promotes intraluminal vesicle delivery of proteins in cells from organisms as phylogenetically apart as fungi and humans. Here we build on these observations by showing that chimeras of fluorescent proteins bearing this sequence, namely, CINCCKVL, which become isoprenylated and palmitoylated in cells, may be used to mark endolysosomes while preserving their morphology. Indeed, these chimeric proteins are devoid of the effects derived from overexpression of fluorescent constructs of full-length, active proteins widely used as endolysosomal markers, such as Lamp1 or Rab7, which cause lysosomal enlargement, or RhoB, which induces actin stress fibers. Moreover, the fact that lipidation-dependent endolysosomal localization of CINCCKVL chimeras can be ascertained in a wide variety of cells indicates that they follow a path toward endolysosomes that is conserved in diverse species. Therefore, CINCCKVL chimeras serve as robust tools to mark these late endocytic compartments.

  6. ChiTaRS-3.1—the enhanced chimeric transcripts and RNA-seq database matched with protein–protein interactions

    Science.gov (United States)

    Gorohovski, Alessandro; Tagore, Somnath; Palande, Vikrant; Malka, Assaf; Raviv-Shay, Dorith; Frenkel-Morgenstern, Milana

    2017-01-01

    Discovery of chimeric RNAs, which are produced by chromosomal translocations as well as the joining of exons from different genes by trans-splicing, has added a new level of complexity to our study and understanding of the transcriptome. The enhanced ChiTaRS-3.1 database (http://chitars.md.biu.ac.il) is designed to make widely accessible a wealth of mined data on chimeric RNAs, with easy-to-use analytical tools built-in. The database comprises 34 922 chimeric transcripts along with 11 714 cancer breakpoints. In this latest version, we have included multiple cross-references to GeneCards, iHop, PubMed, NCBI, Ensembl, OMIM, RefSeq and the Mitelman collection for every entry in the ‘Full Collection’. In addition, for every chimera, we have added a predicted chimeric protein–protein interaction (ChiPPI) network, which allows for easy visualization of protein partners of both parental and fusion proteins for all human chimeras. The database contains a comprehensive annotation for 34 922 chimeric transcripts from eight organisms, and includes the manual annotation of 200 sense-antiSense (SaS) chimeras. The current improvements in the content and functionality to the ChiTaRS database make it a central resource for the study of chimeric transcripts and fusion proteins. PMID:27899596

  7. A Cell-based High-throughput Screening Assay for Farnesoid X Recepter Agonist

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To develop a high-throughput screening assay for Farnesoid X receptor (FXR) agonists based on mammalian one-hybrid system (a chimera receptor gene system) for the purpose of identifying new lead compounds for dyslipidaemia drug from the chemical library. Methods cDNA encoding the human FXR ligand binding domain (LBD) was amplified by RT-PCR from a human liver total mRNA and fused to the DNA binding domain (DBD) of yeast GAL4 of pBIND to construct a GAL4-FXR (LBD) chimera expression plasmid. Five copies of the GAL4 DNA binding site were synthesized and inserted into upstream of the SV40 promoter of pGL3-promoter vector to construct a reporter plasmid pG5-SV40 Luc. The assay was developed by transient co-transfection with pG5-SV40 Luc reporter plasmid and pBIND-FXR-LBD (189-472) chimera expression plasmid. Results After optimization, CDCA, a FXR natural agonist, could induce expression of the luciferase gene in a dose-dependent manner, and had a signal/noise ratio of 10 and Z'factor value of 0.65. Conclusion A stable and sensitive cell-based high-throughput screening model can be used in high-throughput screening for FXR agonists from the synthetic and natural compound library.

  8. Differential requirement for utrophin in the induced pluripotent stem cell correction of muscle versus fat in muscular dystrophy mice.

    Directory of Open Access Journals (Sweden)

    Amanda J Beck

    Full Text Available Duchenne muscular dystrophy (DMD is an incurable degenerative muscle disorder. We injected WT mouse induced pluripotent stem cells (iPSCs into mdx and mdx∶utrophin mutant blastocysts, which are predisposed to develop DMD with an increasing degree of severity (mdx <<< mdx∶utrophin. In mdx chimeras, iPSC-dystrophin was supplied to the muscle sarcolemma to effect corrections at morphological and functional levels. Dystrobrevin was observed in dystrophin-positive and, at a lesser extent, utrophin-positive areas. In the mdx∶utrophin mutant chimeras, although iPSC-dystrophin was also supplied to the muscle sarcolemma, mice still displayed poor skeletal muscle histopathology, and negligible levels of dystrobrevin in dystrophin- and utrophin-negative areas. Not only dystrophin-expressing tissues are affected by iPSCs. Mdx and mdx∶utrophin mice have reduced fat/body weight ratio, but iPSC injection normalized this parameter in both mdx and mdx∶utrophin chimeras, despite the fact that utrophin was compromised in the mdx∶utrophin chimeric fat. The results suggest that the presence of utrophin is required for the iPSC-corrections in skeletal muscle. Furthermore, the results highlight a potential (utrophin-independent non-cell autonomous role for iPSC-dystrophin in the corrections of non-muscle tissue like fat, which is intimately related to the muscle.

  9. A novel genetic system for recombinant protein secretion in the Antarctic Pseudoalteromonas haloplanktis TAC125

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    Marino Gennaro

    2006-12-01

    Full Text Available Abstract Background The final aim of recombinant protein production is both to have a high specific production rate and a high product quality. It was already shown that using cold-adapted bacteria as host vectors, some "intractable" proteins can be efficiently produced at temperature as low as 4°C. Results A novel genetic system for the production and secretion of recombinant proteins in the Antarctic Gram-negative bacterium Pseudoalteromonas haloplanktis TAC125 was set up. This system aims at combining the low temperature recombinant product production with the advantages of extra-cellular protein targeting. The psychrophilic α-amylase from Pseudoalteromonas haloplanktis TAB23 was used as secretion carrier. Three chimerical proteins were produced by fusing intra-cellular proteins to C-terminus of the psychrophilic α-amylase and their secretion was analysed. Data reported in this paper demonstrate that all tested chimeras were translocated with a secretion yield always higher than 80%. Conclusion Data presented here demonstrate that the "cold" gene-expression system is efficient since the secretion yield of tested chimeras is always above 80%. These secretion performances place the α-amylase derived secretion system amongst the best heterologous secretion systems in Gram-negative bacteria reported so far. As for the quality of the secreted passenger proteins, data presented suggest that the system also allows the correct disulphide bond formation of chimera components, secreting a fully active passenger.

  10. A fusion tag to fold on: the S-layer protein SgsE confers improved folding kinetics to translationally fused enhanced green fluorescent protein.

    Science.gov (United States)

    Ristl, Robin; Kainz, Birgit; Stadlmayr, Gerhard; Schuster, Heinrich; Pum, Dietmar; Messner, Paul; Obinger, Christian; Schaffer, Christina

    2012-09-01

    Genetic fusion of two proteins frequently induces beneficial effects to the proteins, such as increased solubility, besides the combination of two protein functions. Here, we study the effects of the bacterial surface layer protein SgsE from Geobacillus stearothermophilus NRS 2004/3a on the folding of a C-terminally fused enhanced green fluorescent protein (EGFP) moiety. Although GFPs are generally unable to adopt a functional confirmation in the bacterial periplasm of Escherichia coli cells, we observed periplasmic fluorescence from a chimera of a 150-amino-acid N-terminal truncation of SgsE and EGFP. Based on this finding, unfolding and refolding kinetics of different S-layer-EGFP chimeras, a maltose binding protein-EGFP chimera, and sole EGFP were monitored using green fluorescence as indicator for the folded protein state. Calculated apparent rate constants for unfolding and refolding indicated different folding pathways for EGFP depending on the fusion partner used, and a clearly stabilizing effect was observed for the SgsE_C fusion moiety. Thermal stability, as determined by differential scanning calorimetry, and unfolding equilibria were found to be independent of the fused partner. We conclude that the stabilizing effect SgsE_C exerts on EGFP is due to a reduction of degrees of freedom for folding of EGFP in the fused state.

  11. Retargeting Clostridium difficile Toxin B to Neuronal Cells as a Potential Vehicle for Cytosolic Delivery of Therapeutic Biomolecules to Treat Botulism

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    Greice Krautz-Peterson

    2012-01-01

    Full Text Available Botulinum neurotoxins (BoNTs deliver a protease to neurons which can cause a flaccid paralysis called botulism. Development of botulism antidotes will require neuronal delivery of agents that inhibit or destroy the BoNT protease. Here, we investigated the potential of engineering Clostridium difficile toxin B (TcdB as a neuronal delivery vehicle by testing two recombinant TcdB chimeras. For AGT-TcdB chimera, an alkyltransferase (AGT was appended to the N-terminal glucosyltransferase (GT of TcdB. Recombinant AGT-TcdB had alkyltransferase activity, and the chimera was nearly as toxic to Vero cells as wild-type TcdB, suggesting efficient cytosolic delivery of the AGT/GT fusion. For AGT-TcdB-BoNT/A-Hc, the receptor-binding domain (RBD of TcdB was replaced by the equivalent RBD from BoNT/A (BoNT/A-Hc. AGT-TcdB-BoNT/A-Hc was >25-fold more toxic to neuronal cells and >25-fold less toxic to Vero cells than AGT-TcdB. Thus, TcdB can be engineered for cytosolic delivery of biomolecules and improved targeting of neuronal cells.

  12. PI3K/Akt signaling pathway involved in regulation of T lymphocyte activation and apoptosis mediated by CD3e

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To study the expression and kinase activity of phosphatidylinositol 3′-kinase (PI3K) and protein kinase B (PKB or Akt) during activation and apoptosis of human Jurkat T lymphocytes (TJK) with stable expression of CD8e chimera fused human CD8a extracellular and transmembra-ne domains to intracellular domain of mouse CD3e, Western blot, kinase activities detection and immunoprecipitation were carried out. It was shown that Jurkat cells with expres-sion of wild type chimera CD8e died by apoptosis after con-tinuous stimulation of anti-CD8 monoclonal antibody. The expressions of PI3K and Akt, and the kinase activity of Akt remarkably increased during the process. However, this phenomenon did not occur in the Jurkat cells (T1JK) with expression of the mutant of CD8e chimera (Y170F), sug-gesting that PI3K/Akt signaling pathway is involved in acti-vation and apoptosis of T lymphocyte mediated by CD3e.

  13. Recombinant streptavidin nanopeptamer anti-immunocomplex assay for noncompetitive detection of small analytes.

    Science.gov (United States)

    Carlomagno, Mariana; Lassabe, Gabriel; Rossotti, Martín; González-Techera, Andrés; Vanrell, Lucía; González-Sapienza, Gualberto

    2014-10-21

    Short peptide loops selected from phage libraries can specifically recognize the formation of hapten-antibody immunocomplexes and can thus be used to develop phage anti-immunocomplex assays (PHAIA) for noncompetitive detection of small molecules. In this study, we generated recombinant chimeras by fusing anti-immunocomplex peptides selected from phage libraries to the N- or C-termini of core streptavidin and used them to setup phage-free noncompetitive assays for the herbicide clomazone (MW 240 Da). The best conditions for refolding were optimized by a high throughput screening allowing to obtain tens of mg of purified protein per liter of culture. The noncompetitive assay developed with these chimeras performed with a 50% saturating concentration (SC50) of 2.2 ± 0.3 ng/mL and limit of detection (LOD) of 0.48 ng/mL. Values that are 13- and 8-fold better that those obtained for the SC50 and LOD of the competitive assay setup with the same antibody. Apart from the first demonstration that recombinant peptide-streptavidin chimeras can be used for sensitive immunodetection of small molecules with a positive readout, this new assay component is a highly standardized reagent with a defined stoichiometry, which can be used in combination with the broad option of existing biotinylated reagents offering a great versatility for the development of conventional immunoassay and biosensors. The utility of the test was demonstrated analyzing the clomazone runoff during the rice growing season in northern Uruguay.

  14. Persistent replication of a hepatitis C virus genotype 1b-based chimeric clone carrying E1, E2 and p6 regions from GB virus B in a New World monkey.

    Science.gov (United States)

    Suzuki, Saori; Mori, Ken-Ichi; Higashino, Atsunori; Iwasaki, Yuki; Yasutomi, Yasuhiro; Maki, Noboru; Akari, Hirofumi

    2016-01-01

    The development of effective hepatitis C virus (HCV) vaccines is essential for the prevention of further HCV dissemination, especially in developing countries. Therefore the aim of this study is to establish a feasible and immunocompetent surrogate animal model of HCV infection that will help in evaluation of the protective efficacy of newly developing HCV vaccine candidates. To circumvent the narrow host range of HCV, an HCV genotype 1b-based chimeric clone carrying E1, E2 and p6 regions from GB virus B (GBV-B), which is closely related to HCV, was generated. The chimera between HCV and GBV-B, named HCV/G, replicated more efficiently as compared with the HCV clone in primary marmoset hepatocytes. Furthermore, it was found that the chimera persistently replicated in a tamarin for more than 2 years after intrahepatic inoculation of the chimeric RNA. Although relatively low (virus. Our results will help establish a novel non-human primate model for HCV infection on the basis of the HCV/G chimera in the major framework of the HCV genome.

  15. Requirement of transmembrane domain for CD154 association to lipid rafts and subsequent biological events.

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    Nadir Benslimane

    Full Text Available Interaction of CD40 with CD154 leads to recruitment of both molecules into lipid rafts, resulting in bi-directional cell activation. The precise mechanism by which CD154 is translocated into lipid rafts and its impact on CD154 signaling remain largely unknown. Our aim is to identify the domain of CD154 facilitating its association to lipid rafts and the impact of such association on signaling events and cytokine production. Thus, we generated Jurkat cell lines expressing truncated CD154 lacking the cytoplasmic domain or chimeric CD154 in which the transmembrane domain was replaced by that of transferrin receptor I, known to be excluded from lipid rafts. Our results show that cell stimulation with soluble CD40 leads to the association of CD154 wild-type and CD154-truncated, but not CD154-chimera, with lipid rafts. This is correlated with failure of CD154-chimera to activate Akt and p38 MAP kinases, known effectors of CD154 signaling. We also found that CD154-chimera lost the ability to promote IL-2 production upon T cell stimulation with anti-CD3/CD28 and soluble CD40. These results demonstrate the implication of the transmembrane domain of CD154 in lipid raft association, and that this association is necessary for CD154-mediated Akt and p38 activation with consequent enhancement of IL-2 production.

  16. Retention of chimeric Tat2-Gap1 permease in the endoplasmic reticulum induces unfolded protein response in Saccharomyces cerevisiae.

    Science.gov (United States)

    Mochizuki, Takahiro; Kimata, Yukio; Uemura, Satoshi; Abe, Fumiyoshi

    2015-08-01

    In Saccharomyces cerevisiae, high-affinity tryptophan import is performed by subtle mechanisms involving tryptophan permease Tat2. We have shown that Tat2 requires 15 amino acid residues in the transmembrane domains (TMDs) for its import activity, whereas leucine permease Bap2 requires only seven corresponding residues for its leucine import. For this reason, the structure of Tat2 is elaborately designed to transport the hydrophobic and bulky tryptophan. Newly synthesized cell surface proteins first undergo endoplasmic reticulum (ER)-associated quality check before entering the secretory pathway. In this study, we used domain replacement with general amino acid permease Gap1 to show that Tat2 chimeric proteins were dysfunctional when TMD10 or TMD11 was replaced. These chimeras formed large 270-800-kDa protein complexes and were stably retained in the ER membrane without efficient degradation. In contrast, Tat2 chimeras of TMD9 or TMD12 retained some of their tryptophan import activity and underwent vacuolar degradation as observed with wild-type Tat2. Thus, ours results suggest that TMD10 and TMD11 are essential for the correct folding of Tat2, probably because of their interdomain interactions. Notably, overexpression of Tat2-Gap1 chimera of TMD10 activated the unfolded protein response (UPR) element-lacZ reporter, suggesting that ER retention of the protein aggregates induces the UPR.

  17. In vivo analysis of the helix-turn-helix motif of the fushi tarazu homeo domain of Drosophila melanogaster.

    Science.gov (United States)

    Furukubo-Tokunaga, K; Müller, M; Affolter, M; Pick, L; Kloter, U; Gehring, W J

    1992-06-01

    We report a systematic mutational analysis of the helix-turn-helix motif (HTH) of the fushi tarazu (ftz) homeo domain (HD) of Drosophila. We started out by testing the function of chimeric ftz proteins containing either a part of the Sex combs reduced (Scr) or the muscle segment homeobox (msh) HDs. By complementation tests in transgenic flies, cotransfection assays in cultured Drosophila cells and in vitro DNA-binding assays, we have found that the ftz activity is retained in the ftz-Scr chimera but is lost in the ftz-msh chimera, which is defective in binding to an Antennapedia (Antp)-class target site. Further studies with a series of back-mutants of the ftz-msh chimera have revealed that a set of class-specific DNA backbone-contacting residues in the HTH, particularly Arg-28 and Arg-43, are required for efficient target site recognition and, hence, full ftz activity both in vitro and in vivo.

  18. Biased clique shuffling reveals stabilizing mutations in cellulase Cel7A.

    Science.gov (United States)

    Dana, Craig M; Saija, Poonam; Kal, Sarala M; Bryan, Mara B; Blanch, Harvey W; Clark, Douglas S

    2012-11-01

    Renewable fuels produced from biomass-derived sugars are receiving increasing attention. Lignocellulose-degrading enzymes derived from fungi are attractive for saccharification of biomass because they can be produced at higher titers and at significantly less cost than those produced by bacteria or archaea. However, their properties can be suboptimal; for example, they are subject to product inhibition and are sensitive to small changes in pH. Furthermore, increased thermostability would be advantageous for saccharification as increased temperature may reduce the opportunity for microbial contamination. We have developed a mutagenesis platform to improve these properties and applied it to increase the operating temperature and thermostability of the fungal glycosyl hydrolase Cel7A. Secretion of Cel7A at titers of 26 mg/L with limited hyperglycosylation was achieved using a Saccharomyces cerevisiae strain with upregulated protein disulfide isomerase, an engineered α-factor prepro leader, and deletion of a plasma membrane ATPase. Using biased clique shuffling (BCS) of 11 Cel7A genes, we generated a small library (469) rich in activity (86% of the chimeras were active) and identified 51 chimeras with improved thermostability, many of which contained mutations in the loop networks that extend over the enzyme's active site. This BCS library was far superior as a source of active and stable chimeras compared to an equimolar library prepared from the same 11 genes.

  19. Proteasome inhibition compromises direct retention of cytochrome P450 2C2 in the endoplasmic reticulum.

    Science.gov (United States)

    Szczesna-Skorupa, Elzbieta; Kemper, Byron

    2008-10-15

    To determine whether protein degradation plays a role in the endoplasmic reticulum (ER) retention of cytochromes P450, the effects of proteasomal inhibitors on the expression and distribution of green fluorescent protein chimeras of CYP2C2 and related proteins was examined. In transfected cells, expression levels of chimeras of full-length CYP2C2 and its cytosolic domain, but not its N-terminal transmembrane sequence, were increased by proteasomal inhibition. Redistribution of all three chimeras from the reticular ER into a perinuclear compartment and, in a subset of cells, also to the cell surface was observed after proteasomal inhibition. Redistribution was blocked by the microtubular inhibitor, nocodazole, suggesting that redistribution to the cell surface followed the conventional vesicular transport pathway. Similar redistributions were detected for BAP31, a CYP2C2 binding chaperone; CYP2E1 and CYP3A4, which are also degraded by the proteasomal pathway; and for cytochrome P450 reductase, which does not undergo proteasomal degradation; but not for the ER membrane proteins, sec61 and calnexin. Redistribution does not result from saturation of an ER retention "receptor" since in some cases protein levels were unaffected. Proteasomal inhibition may, therefore, alter ER retention by affecting a protein critical for ER retention, either directly, or indirectly by affecting the composition of the ER membranes.

  20. Extended polyglutamine tracts cause aggregation and structural perturbation of an adjacent beta barrel protein.

    Science.gov (United States)

    Ignatova, Zoya; Gierasch, Lila M

    2006-05-05

    Formation of fibrillar intranuclear inclusions and related neuropathologies of the CAG-repeat disorders are linked to the expansion of a polyglutamine tract. Despite considerable effort, the etiology of these devastating diseases remains unclear. Although polypeptides with glutamine tracts recapitulate many of the observed characteristics of the gene products with CAG repeats, such as in vitro and in vivo aggregation and toxicity in model organisms, extended polyglutamine segments have also been reported to structurally perturb proteins into which they are inserted. Additionally, the sequence context of a polyglutamine tract has recently been shown to modulate its propensity to aggregate. These findings raise the possibility that indirect influences of the repeat tract on adjacent protein domains are contributory to pathologies. Destabilization of an adjacent domain may lead to loss of function, as well as favoring non-native structures in the neighboring domain causing them to be prone to intermolecular association and consequent aggregation. To explore these phenomena, we have used chimeras of a well studied globular protein and exon 1 of huntingtin. We find that expansion of the polyglutamine segment beyond the pathological threshold (>35 glutamines) results in structural perturbation of the neighboring protein whether the huntingtin exon is N- or C-terminal. Elongation of the polyglutamine region also substantially increases the propensity of the chimera to aggregate, both in vitro and in vivo, and in vitro aggregation kinetics of a chimera with a 53-glutamine repeat follow a nucleation polymerization mechanism with a monomeric nucleus.

  1. Association of telomere length with authentic pluripotency of ES/iPS cells

    Institute of Scientific and Technical Information of China (English)

    Junjiu Huang; William W Ge; John CM Tsibris; David L Keefe; Lin Liu; Fang Wang; Maja Okuka; Na Liu; Guangzhen Ji; Xiaoying Ye; Bingfeng Zuo; Minshu Li; Ping Liang

    2011-01-01

    Telomerase and telomeres are important for indefinite replication of stem cells. Recently, telomeres of somatic cells were found to be reprogrammed to elongate in induced pluripotent stem cells(iPSCs). The role of telomeres in developmental pluripotency in vivo of embryonic stem cells(ESCs)or iPSCs, however, has not been directly addressed.We show that ESCs with long telomeres exhibit authentic developmental pluripotency, as evidenced by generation of complete ESC pups as well as germline-competent chimeras, the most stringent tests available in rodents. ESCs with short telomeres show reduced teratoma formation and chimera production, and fail to generate complete ESC pups. Telomere lengths are highly correlated(r>0.8)with the developmental pluripotency of ESCs. Short telomeres decrease the proliferative rate or capacity of ESCs, alter the expression of genes related to telomere epigenetics,down-regulate genes important for embryogenesis and disrupt germ cell differentiation. Moreover, iPSCs with longer telomeres generate chimeras with higher efficiency than those with short telomeres. Our data show that functional telomeres are essential for the developmental pluripotency of ESCs/iPSCs and suggest that telomere length may provide a valuable marker to evaluate stem cell pluripotency, particularly when the stringent tests are not feasible.

  2. Removing Noise From Pyrosequenced Amplicons

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    Davenport Russell J

    2011-01-01

    Full Text Available Abstract Background In many environmental genomics applications a homologous region of DNA from a diverse sample is first amplified by PCR and then sequenced. The next generation sequencing technology, 454 pyrosequencing, has allowed much larger read numbers from PCR amplicons than ever before. This has revolutionised the study of microbial diversity as it is now possible to sequence a substantial fraction of the 16S rRNA genes in a community. However, there is a growing realisation that because of the large read numbers and the lack of consensus sequences it is vital to distinguish noise from true sequence diversity in this data. Otherwise this leads to inflated estimates of the number of types or operational taxonomic units (OTUs present. Three sources of error are important: sequencing error, PCR single base substitutions and PCR chimeras. We present AmpliconNoise, a development of the PyroNoise algorithm that is capable of separately removing 454 sequencing errors and PCR single base errors. We also introduce a novel chimera removal program, Perseus, that exploits the sequence abundances associated with pyrosequencing data. We use data sets where samples of known diversity have been amplified and sequenced to quantify the effect of each of the sources of error on OTU inflation and to validate these algorithms. Results AmpliconNoise outperforms alternative algorithms substantially reducing per base error rates for both the GS FLX and latest Titanium protocol. All three sources of error lead to inflation of diversity estimates. In particular, chimera formation has a hitherto unrealised importance which varies according to amplification protocol. We show that AmpliconNoise allows accurate estimates of OTU number. Just as importantly AmpliconNoise generates the right OTUs even at low sequence differences. We demonstrate that Perseus has very high sensitivity, able to find 99% of chimeras, which is critical when these are present at high

  3. Conformational influence of the ribose 2'-hydroxyl group: crystal structures of DNA-RNA chimeric duplexes

    Science.gov (United States)

    Egli, M.; Usman, N.; Rich, A.

    1993-01-01

    We have crystallized three double-helical DNA-RNA chimeric duplexes and determined their structures by X-ray crystallography at resolutions between 2 and 2.25 A. The two self-complementary duplexes [r(G)d(CGTATACGC)]2 and [d(GCGT)r(A)d(TACGC)]2, as well as the Okazaki fragment d(GGGTATACGC).r(GCG)d(TATACCC), were found to adopt A-type conformations. The crystal structures are non-isomorphous, and the crystallographic environments for the three chimeras are different. A number of intramolecular interactions of the ribose 2'-hydroxyl groups contribute to the stabilization of the A-conformation. Hydrogen bonds between 2'-hydroxyls and 5'-oxygens or phosphate oxygens, in addition to the previously observed hydrogen bonds to 1'-oxygens of adjacent riboses and deoxyriboses, are observed in the DNA-RNA chimeric duplexes. The crystalline chimeric duplexes do not show a transition between the DNA A- and B-conformations. CD spectra suggest that the Okazaki fragment assumes an A-conformation in solution as well. In this molecule the three RNA residues may therefore lock the complete decamer in the A-conformation. Crystals of an all-DNA strand with the same sequence as the self-complementary chimeras show a morphology which is different from those of the chimera crystals. Moreover, the oligonucleotide does not match any of the sequence characteristics of DNAs usually adopting the A-conformation in the crystalline state (e.g., octamers with short alternating stretches of purines and pyrimidines). In DNA-RNA chimeric duplexes, it is therefore possible that a single RNA residue can drive the conformational equilibrium toward the A-conformation.

  4. Dimerization Domain of Retinal Membrane Guanylyl Cyclase 1 (RetGC1) Is an Essential Part of Guanylyl Cyclase-activating Protein (GCAP) Binding Interface.

    Science.gov (United States)

    Peshenko, Igor V; Olshevskaya, Elena V; Dizhoor, Alexander M

    2015-08-01

    The photoreceptor-specific proteins guanylyl cyclase-activating proteins (GCAPs) bind and regulate retinal membrane guanylyl cyclase 1 (RetGC1) but not natriuretic peptide receptor A (NPRA). Study of RetGC1 regulation in vitro and its association with fluorescently tagged GCAP in transfected cells showed that R822P substitution in the cyclase dimerization domain causing congenital early onset blindness disrupted RetGC1 ability to bind GCAP but did not eliminate its affinity for another photoreceptor-specific protein, retinal degeneration 3 (RD3). Likewise, the presence of the NPRA dimerization domain in RetGC1/NPRA chimera specifically disabled binding of GCAPs but not of RD3. In subsequent mapping using hybrid dimerization domains in RetGC1/NPRA chimera, multiple RetGC1-specific residues contributed to GCAP binding by the cyclase, but the region around Met(823) was the most crucial. Either positively or negatively charged residues in that position completely blocked GCAP1 and GCAP2 but not RD3 binding similarly to the disease-causing mutation in the neighboring Arg(822). The specificity of GCAP binding imparted by RetGC1 dimerization domain was not directly related to promoting dimerization of the cyclase. The probability of coiled coil dimer formation computed for RetGC1/NPRA chimeras, even those incapable of binding GCAP, remained high, and functional complementation tests showed that the RetGC1 active site, which requires dimerization of the cyclase, was formed even when Met(823) or Arg(822) was mutated. These results directly demonstrate that the interface for GCAP binding on RetGC1 requires not only the kinase homology region but also directly involves the dimerization domain and especially its portion containing Arg(822) and Met(823).

  5. Engineered bacterial hydrophobic oligopeptide repeats in a synthetic yeast prion, [REP-PSI+

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    Fátima eGasset-Rosa

    2015-04-01

    Full Text Available The yeast translation termination factor Sup35p, by aggregating as the [PSI+] prion, enables ribosomes to read-through stop codons, thus expanding the diversity of the Saccharomyces cerevisiae proteome. Yeast prions are functional amyloids that replicate by templating their conformation on native protein molecules, then assembling as large aggregates and fibers. Prions propagate epigenetically from mother to daughter cells by fragmentation of such assemblies. In the N-terminal prion-forming domain, Sup35p has glutamine/asparagine-rich oligopeptide repeats (OPRs, which enable propagation through chaperone-elicited shearing. We have engineered chimeras by replacing the polar OPRs in Sup35p by up to five repeats of a hydrophobic amyloidogenic sequence from the synthetic bacterial prionoid RepA-WH1. The resulting hybrid, [REP-PSI+], i was functional in a stop codon read-through assay in S. cerevisiae; ii generates weak phenotypic variants upon both its expression or transformation into [psi-] cells; iii these variants correlated with high molecular weight aggregates resistant to SDS during electrophoresis; and iv according to fluorescence microscopy, the fusion of the prion domains from the engineered chimeras to the reporter protein mCherry generated perivacuolar aggregate foci in yeast cells. All these are signatures of bona fide yeast prions. As assessed through biophysical approaches, the chimeras assembled as oligomers rather than as the fibers characteristic of [PSI+]. These results suggest that it is the balance between polar and hydrophobic residues in OPRs what determines prion conformational dynamics. In addition, our findings illustrate the feasibility of enabling new propagation traits in yeast prions by engineering OPRs with heterologous amyloidogenic sequence repeats.

  6. Development of live attenuated Bordetella pertussis strains expressing the universal influenza vaccine candidate M2e.

    Science.gov (United States)

    Li, Rui; Lim, Annabelle; Ow, Stephanie T L; Phoon, Meng Chee; Locht, Camille; Chow, Vincent T; Alonso, Sylvie

    2011-07-26

    The attenuated Bordetella pertussis BPZE1 vaccine strain represents an attractive platform for the delivery of heterologous vaccine candidates via the nasal route. The filamentous hemagglutinin (FHA) has been used to secrete or expose the foreign antigens at the bacterial surface. In this study, one, two and three copies of the Cys-containing ectodomain of matrix protein 2 (M2e) from influenza A virus were genetically fused to full length FHA and expressed in BPZE1. The secretion efficacy of the FHA-(M2e)(1,2,3) chimera in the extracellular milieu and the ability of the recombinant bacteria to colonize the mouse lungs inversely correlated with the number of M2e copies fused to FHA. Nevertheless FHA-(M2e)(3)-producing bacteria (BPLR3) triggered the highest systemic anti-M2e antibody response upon nasal administration to BALB/c mice. Nasal immunization with BPLR3 bacteria resulted in a significant reduction in the viral loads upon challenge with H1N1/PR8 influenza A virus, but did not improve the survival rate compared to BPZE1-immunized mice. Furthermore, since previous work reported that disulfide bond formation in Cys-containing passenger antigens affects the secretion efficacy of the FHA chimera, the dsbA gene encoding a periplasmic disulfide isomerase was deleted in the FHA-(M2e)(3)-producing strain. Despite improving significantly the secretion efficacy of the FHA-(M2e)(3) chimera, the dsbA deletion did not result in higher anti-M2e antibody titers in mice, due to impaired bacterial fitness and colonization ability.

  7. Specificity for a CCR5 Inhibitor Is Conferred by a Single Amino Acid Residue: ROLE OF ILE198.

    Science.gov (United States)

    Lau, Gloria; Labrecque, Jean; Metz, Markus; Vaz, Roy; Fricker, Simon P

    2015-04-24

    The chemokine receptors CCR5 and CCR2b share 89% amino acid homology. CCR5 is a co-receptor for HIV and CCR5 antagonists have been investigated as inhibitors of HIV infection. We describe the use of two CCR5 antagonists, Schering-C (SCH-C), which is specific for CCR5, and TAK-779, a dual inhibitor of CCR5 and CCR2b, to probe the CCR5 inhibitor binding site using CCR5/CCR2b chimeric receptors. Compound inhibition in the different chimeras was assessed by inhibition of chemokine-induced calcium flux. SCH-C inhibited RANTES (regulated on activation, normal T cell expressed and secreted) (CCL5)-mediated calcium flux on CCR5 with an IC50 of 22.8 nM but was inactive against monocyte chemoattractant protein-1 (CCL2)-mediated calcium flux on CCR2b. However, SCH-C inhibited CCL2-induced calcium flux against a CCR5/CCR2b chimera consisting of transmembrane domains IV-VI of CCR5 with an IC50 of 55 nM. A sequence comparison of CCR5 and CCR2b identified a divergent amino acid sequence located at the junction of transmembrane domain V and second extracellular loop. Transfer of the CCR5 sequence KNFQTLKIV into CCR2b conferred SCH-C inhibition (IC50 of 122 nM) into the predominantly CCR2b chimera. Furthermore, a single substitution, R206I, conferred partial but significant inhibition (IC50 of 1023 nM) by SCH-C. These results show that a limited amino acid sequence is responsible for SCH-C specificity to CCR5, and we propose a model showing the interaction with CCR5 Ile(198).

  8. The First Extracellular Domain Plays an Important Role in Unitary Channel Conductance of Cx50 Gap Junction Channels.

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    Xiaoling Tong

    Full Text Available Gap junction (GJ channels provide direct passage for ions and small molecules to be exchanged between neighbouring cells and are crucial for many physiological processes. GJ channels can be gated by transjunctional voltage (known as Vj-gating and display a wide range of unitary channel conductance (γj, yet the domains responsible for Vj-gating and γj are not fully clear. The first extracellular domain (E1 of several connexins has been shown to line part of their GJ channel pore and play important roles in Vj-gating properties and/or ion permeation selectivity. To test roles of the E1 of Cx50 GJ channels, we generated a chimera, Cx50Cx36E1, where the E1 domain of Cx50 was replaced with that of Cx36, a connexin showing quite distinct Vj-gating and γj from those of Cx50. Detailed characterizations of the chimera and three point mutants in E1 revealed that, although the E1 domain is important in determining γj, the E1 domain of Cx36 is able to effectively function within the context of the Cx50 channel with minor changes in Vj-gating properties, indicating that sequence differences between the E1 domains in Cx36 and Cx50 cannot account for their drastic differences in Vj-gating and γj. Our homology models of the chimera and the E1 mutants revealed that electrostatic properties of the pore-lining residues and their contribution to the electric field in the pore are important factors for the rate of ion permeation of Cx50 and possibly other GJ channels.

  9. Anti-T-lymphocyte globulin-based non-myeloablative stem cell transplantation followed by HLA-identical donor lymphocyte infusion for hematologic malignancies

    Institute of Scientific and Technical Information of China (English)

    毛平; 王顺清; 王汉平; 李庆山; 许艳丽; 莫文健; 应逸; 朱志刚

    2003-01-01

    Objective To evaluate the application of anti-T-lymphocyte globulin (ATG) based nonmyeloablative but profoundly immunosuppressive regimens followed by donor lymphocyte infusion (DLI) for the treatment of hematologic malignancies.Methods The protocol was designed to minimize the intensity of the conditioning regimen to the range of nonmyeloablative therapies based on ATG with low-dose busulfan (Bu) and Cytoxan (CTX) (15-19.5 mg/kg, 8 mg/kg and 80 mg/kg, respectively). The patients received the first lymphocytic infusion from HLA-identical sibling donors on days 28-30 after transplant, and the first T cell dosage of 106/kg followed by the escalated dosage in the range of (0.5-1.5)×108/kg. The total number of procedures were performed at a median of 4.2 procedures (range of 2-8 procedures).Results Engraftment was documented in all six patients in the form of donor-recipient hematopoietic cells mixed chimera at early-stage posttransplant, which was converted gradually into complet chimera by DLI in four patients. Graft-versus-host disease (GVHD) developed in three of six cases, only one of which was severe. To date,four patients are disease free and alive.Conclusions Allogeneic donor stem cell engraftment into host can be achieved by nonmyeloablative conditioning regimen based on ATG. Transient mixed donor-recipient hematopoietic cell mixed with chimeras may be successfully converted into complete chimerism by DLI posttransplant. GVHD remains major clinical concern in our study.

  10. Influence of the hinge region and its adjacent domains on binding and signaling patterns of the thyrotropin and follitropin receptor.

    Directory of Open Access Journals (Sweden)

    Jörg Schaarschmidt

    Full Text Available Glycoprotein hormone receptors (GPHR have a large extracellular domain (ECD divided into the leucine rich repeat (LRR domain for binding of the glycoprotein hormones and the hinge region (HinR, which connects the LRR domain with the transmembrane domain (TMD. Understanding of the activation mechanism of GPHRs is hindered by the unknown interaction of the ECD with the TMD and the structural changes upon ligand binding responsible for receptor activation. Recently, our group showed that the HinR of the thyrotropin receptor (TSHR can be replaced by those of the follitropin (FSHR and lutropin receptor (LHCGR without effects on surface expression and hTSH signaling. However, differences in binding characteristics for bovine TSH at the various HinRs were obvious. To gain further insights into the interplay between LRR domain, HinR and TMD we generated chimeras between the TSHR and FSHR. Our results obtained by the determination of cell surface expression, ligand binding and G protein activation confirm the similar characteristics of GPHR HinRs but they also demonstrate an involvement of the HinR in ligand selectivity indicated by the observed promiscuity of some chimeras. While the TSHR HinR contributes to specific binding of TSH and its variants, no such contribution is observed for FSH and its analog TR4401 at the HinR of the FSHR. Furthermore, the charge distribution at the poorly characterized LRR domain/HinR transition affected ligand binding and signaling even though this area is not in direct contact with the ligand. In addition our results also demonstrate the importance of the TMD/HinR interface. Especially the combination of the TSHR HinR with the FSHR-TMD resulted in a loss of cell surface expression of the respective chimeras. In conclusion, the HinRs of GPHRs do not only share similar characteristics but also behave as ligand specific structural and functional entities.

  11. Role of sialyloligosaccharide binding in Theiler's virus persistence.

    Science.gov (United States)

    Zhou, L; Lin, X; Green, T J; Lipton, H L; Luo, M

    1997-12-01

    Theiler's murine encephalomyelitis viruses (TMEVs) belong to the Picornaviridae family and are divided into two groups, typified by strain GDVII virus and members of the TO (Theiler's original) group. The highly virulent GDVII group causes acute encephalitis in mice, while the TO group is less virulent and causes a chronic demyelinating disease which is associated with viral persistence in mice. This persistent central nervous system infection with demyelination resembles multiple sclerosis (MS) in humans and has thus become an important model for studying MS. It has been shown that some of the determinants associated with viral persistence are located on the capsid proteins of the TO group. Structural comparisons of two persistent strains (BeAn and DA) and a highly virulent strain (GDVII) showed that the most significant structural variations between these two groups of viruses are located on the sites that may influence virus binding to cellular receptors. Most animal viruses attach to specific cellular receptors that, in part, determine host range and tissue tropism. In this study, atomic models of TMEV chimeras were built with the known structures of GDVII, BeAn, and DA viruses. Comparisons among the known GDVII, BeAn, and DA structures as well as the predicted models for the TMEV chimeras suggested that a gap on the capsid surface next to the putative receptor binding site, composed of residues from VP1 and VP2, may be important in determining viral persistence by influencing virus attachment to cellular receptors, such as sialyloligosaccharides. Our results showed that sialyllactose, the first three sugar molecules of common oligosaccharides on the surface of mammalian cells, inhibits virus binding to the host cell and infection with the persistent BeAn virus but not the nonpersistent GDVII and chimera 39 viruses.

  12. Contribution of the S5-pore-S6 domain to the gating characteristics of the cation channels TRPM2 and TRPM8.

    Science.gov (United States)

    Kühn, Frank J P; Witschas, Katja; Kühn, Cornelia; Lückhoff, Andreas

    2010-08-27

    The closely related cation channels TRPM2 and TRPM8 show completely different requirements for stimulation and are regulated by Ca(2+) in an opposite manner. TRPM8 is basically gated in a voltage-dependent process enhanced by cold temperatures and cooling compounds such as menthol and icilin. The putative S4 voltage sensor of TRPM8 is closely similar to that of TRPM2, which, however, is mostly devoid of voltage sensitivity. To gain insight into principal interactions of critical channel domains during the gating process, we created chimeras in which the entire S5-pore-S6 domains were reciprocally exchanged. The chimera M2-M8P (i.e. TRPM2 with the pore of TRPM8) responded to ADP-ribose and hydrogen peroxide and was regulated by extracellular and intracellular Ca(2+) as was wild-type TRPM2. Single-channel recordings revealed the characteristic pattern of TRPM2 with extremely long open times. Only at far-negative membrane potentials (-120 to -140 mV) did differences become apparent because currents were reduced by hyperpolarization in M2-M8P but not in TRPM2. The reciprocal chimera, M8-M2P, showed currents after stimulation with high concentrations of menthol and icilin, but these currents were only slightly larger than in controls. The transfer of the NUDT9 domain to the C terminus of TRPM8 produced a channel sensitive to cold, menthol, or icilin but insensitive to ADP-ribose or hydrogen peroxide. We conclude that the gating processes in TRPM2 and TRPM8 differ in their requirements for specific structures within the pore. Moreover, the regulation by extracellular and intracellular Ca(2+) and the single-channel properties in TRPM2 are not determined by the S5-pore-S6 region.

  13. Critique of Optical Negative Refraction Superlensing

    CERN Document Server

    Christou, George

    2010-01-01

    Has the ten-year old quest for the optical superlens, based on Veselago's hypothesis of negative refraction, been a chimera? We argue that Pendry's alternative prescription of the silver superlens is nothing more than an application of the natural phenomenon of surface plasmon resonance that occurs in the noble metal films. This phenomenon does not predict the reality of Veselago's negative refractive index materials. We give a simple explanation of how this resonance achieves a field intensity enhancement at the interface of silver and air without involving the concept of negative refraction.

  14. A novel cell subset:Interferon-producing killer dendritic cells

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Recent reports introduce a novel cell subset of DCs with antigenic phenotypes shared by both NK cells and B cells, but without surface markers of pDCs and T cells, appearing to be a chimera of NK cells and DCs, namely interferon-producing killer dendritic cells(IKDCs).IKDCs not only secret type I and type II interferons to recognize and kill tumor cells effectively, but also express MHC-II molecules to present antigens.Thus, IKDCs are considered as important immunosurveilance cells for tumors, providing a link between innate and adaptive immunity.

  15. APOBEC3F determinants of HIV-1 Vif sensitivity.

    Science.gov (United States)

    Land, Allison M; Shaban, Nadine M; Evans, Leah; Hultquist, Judd F; Albin, John S; Harris, Reuben S

    2014-11-01

    HIV-1 Vif counteracts restrictive APOBEC3 proteins by targeting them for proteasomal degradation. To determine the regions mediating sensitivity to Vif, we compared human APOBEC3F, which is HIV-1 Vif sensitive, with rhesus APOBEC3F, which is HIV-1 Vif resistant. Rhesus-human APOBEC3F chimeras and amino acid substitution mutants were tested for sensitivity to HIV-1 Vif. This approach identified the α3 and α4 helices of human APOBEC3F as important determinants of the interaction with HIV-1 Vif.

  16. Synthesis of Peptide-Oligonucleotide Conjugates Using a Heterobifunctional Crosslinker

    Science.gov (United States)

    Williams, Berea A.R.; Chaput, John C.

    2010-01-01

    Peptide-oligonucleotide conjugates (POCs) are molecular chimeras composed of a nucleic acid moiety covalently attached to a polypeptide moiety. POCs have been used in numerous applications from therapeutics to nanotechnology, and most recently as combinatorial agents in the assembly of bivalent protein affinity reagents. This unit describes the synthesis and purification of POC molecules using the heterobifunctional crosslinking reagent succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC), which enables amine-modified oligonucleotides to become covalently linked to cysteine-modified polypeptides. This solution-based protocol consists of a two-step synthesis followed by a single purification step. PMID:20827717

  17. La metaficción en México y los Estados Unidos

    OpenAIRE

    2012-01-01

    En este trabajo, realizamos un estudio comparativo de textos literarios seleccionados, por una parte, en México: Juan José Arreola (palindroma, 1971), Salvador Elizondo (farabeuf, 1965 y el hipogeo secreto, 1968), Vicente Leñero (estudio q, 1965), y, por otra parte, en los estados unidos: John Barth (lost in the funhouse, 1968, chimera, 1972), Robert Coover (spanking the maid, 1982) y Raymond Federman (take it or leave it, 1975), tomando como punto de partida y rasgo esencial la autorreferenc...

  18. Integrating Software Modules For Robot Control

    Science.gov (United States)

    Volpe, Richard A.; Khosla, Pradeep; Stewart, David B.

    1993-01-01

    Reconfigurable, sensor-based control system uses state variables in systematic integration of reusable control modules. Designed for open-architecture hardware including many general-purpose microprocessors, each having own local memory plus access to global shared memory. Implemented in software as extension of Chimera II real-time operating system. Provides transparent computing mechanism for intertask communication between control modules and generic process-module architecture for multiprocessor realtime computation. Used to control robot arm. Proves useful in variety of other control and robotic applications.

  19. KSR-Based Medium Improves the Generation of High-Quality Mouse iPS Cells

    OpenAIRE

    2014-01-01

    Induced pluripotent stem (iPS) cells from somatic cells have great potential for regenerative medicine. The efficiency in generation of iPS cells has been significantly improved in recent years. However, the generation of high-quality iPS cells remains of high interest. Consistently, we demonstrate that knockout serum replacement (KSR)-based medium accelerates iPS cell induction and improves the quality of iPS cells, as confirmed by generation of chimeras and all iPS cell-derived offspring wi...

  20. Membrane heredity and early chloroplast evolution.

    Science.gov (United States)

    Cavalier-Smith, T

    2000-04-01

    Membrane heredity was central to the unique symbiogenetic origin from cyanobacteria of chloroplasts in the ancestor of Plantae (green plants, red algae, glaucophytes) and to subsequent lateral transfers of plastids to form even more complex photosynthetic chimeras. Each symbiogenesis integrated disparate genomes and several radically different genetic membranes into a more complex cell. The common ancestor of Plantae evolved transit machinery for plastid protein import. In later secondary symbiogeneses, signal sequences were added to target proteins across host perialgal membranes: independently into green algal plastids (euglenoids, chlorarachneans) and red algal plastids (alveolates, chromists). Conservatism and innovation during early plastid diversification are discussed.

  1. IMMUNORESPONSES OF HUMANIZED SCID MICE TO HUMAN LUNG CANCER CELLS

    Institute of Scientific and Technical Information of China (English)

    陈力真; 王树蕙; 张云; 王世真

    1996-01-01

    HuPBL-SCID mice were used to explore how they would response to human ttmoor cells of 801/MLC.Living 801/MLC cells appeared to be fetal to the the mice due to the production of human TNF. The huP-BL-SCID rniee did not generate any noticeable amotmt of specific human immunoglobttlin either by single immunization with living 801/MLC cells or by repeated immunization with irradiated 801/MLC cells. Our preliminary experiments with huPBL-SCID mice showed that such chimeras would he a very useful models for tumor immunological researches.

  2. [Facial graft, archetype of microsurgical innovation?].

    Science.gov (United States)

    Devauchelle, B; Testelin, S; Dakpe, S; Lengelé, B; Dubernard, J-M

    2010-10-01

    Is innovation breaking of the way of thinking, breaker of taboos, concretisation of chimeras or simple benefit of an ineluctable evolution? The surgical act should be considered as innovation itself? From the first facial allotransplantation, innovation is declined in various ways, which could constitute the different answers regarding the planning and management to prepare such surgery, the realisation of the transplantation and also the multiple developments in terms of science and medicine. It is exactly in that meaning that could be really mentioned the term archetypal.

  3. Campaign of measurements to probe the good performance of the new array FARCOS for spectroscopy and correlations.

    Science.gov (United States)

    Acosta, L.; Andolina, R.; Auditore, L.; Boiano, C.; Cardella, G.; Castoldi, A.; D'Andrea, M.; De Filippo, E.; De Luca, S.; Dell'Aquila, D.; Francalanza, L.; Gnoffo, B.; Guazzoni, C.; Lanzalone, G.; Lombardo, I.; Martorana, N.; Minniti, T.; Norella, S.; Pagano, A.; Pagano, E. V.; Papa, M.; Parsani, T.; Pirrone, S.; Politi, G.; Porto, F.; Quattrocchi, L.; Rizzo, F.; Russotto, P.; Saccá, G.; Trifirò, A.; Trimarchi, M.; Verde, G.; Vigilante, M.; Zambon, P.

    2016-07-01

    During the last four years, several measurements have been carried out where the capabilities of FARCOS array were tested. In some of this occasions, FARCOS was coupled to the 4π array CHIMERA, permanently placed at INFN-Laboratori Nazionali del Sud, Catania in order to be tested in real experimental measurements. At the present situation, the FARCOS demonstrator is formed by 4 telescopes out of the originally 20 that will constitute the final array. Here are presented some preliminary results obtained with the new array, probing its qualities and showing the effectiveness of FARCOS telescopes. The initial encouraging results support the construction of the complete array.

  4. Modification of T cell responses by stem cell mobilization requires direct signaling of the T cell by G-CSF and IL-10

    DEFF Research Database (Denmark)

    MacDonald, Kelli P.A.; Le Texier, Laetitia; Zhang, Ping

    2014-01-01

    -resistant tissue, and was not required to be produced by T cells. G-CSF mobilization significantly modulated the transcription profile of CD4(+)CD25(+) regulatory T cells, promoted their expansion in the donor and recipient and their depletion significantly increased graft-versus-host disease (GVHD). In contrast......The majority of allogeneic stem cell transplants are currently undertaken using G-CSF mobilized peripheral blood stem cells. G-CSF has diverse biological effects on a broad range of cells and IL-10 is a key regulator of many of these effects. Using mixed radiation chimeras in which...

  5. Mosaic tetracycline resistance genes encoding ribosomal protection proteins.

    Science.gov (United States)

    Warburton, Philip J; Amodeo, Nina; Roberts, Adam P

    2016-12-01

    First reported in 2003, mosaic tetracycline resistance genes are a subgroup of the genes encoding ribosomal protection proteins (RPPs). They are formed when two or more RPP-encoding genes recombine resulting in a functional chimera. To date, the majority of mosaic genes are derived from sections of three RPP genes, tet(O), tet(W) and tet(32), with others comprising tet(M) and tet(S). In this first review of mosaic genes, we report on their structure, diversity and prevalence, and suggest that these genes may be responsible for an under-reported contribution to tetracycline resistance in bacteria.

  6. LIPASES PRODUCED BY YEASTS: POWERFUL BIOCATALYSTS FOR INDUSTRIAL PURPOSES

    Directory of Open Access Journals (Sweden)

    Luiza Lux Lock

    2007-12-01

    Full Text Available The term “lipolytic enzymes” refers to the lipases and carboxylic ester hydrolases. Lipase production is widespread among yeasts, but few are capable of producing lipases with interesting characteristics and in sufficient amounts to be industrially useful. The literature concerning lipases produced by Candida rugosa, Yarrowia (Candida lipolytica, Candida antarctica and other emerging lipase-producing yeasts is reviewed. The use of recombinant lipases is discussed, with emphasis on the utilization of heterologous expression systems and design of chimeras. Finally, the three approaches that aim the improvement of lipase production or the modification of the substrate selectivity of the enzyme (medium engineering, biocatalyst engineering, and protein engineering are discussed.

  7. Compositions and Methods for the Treatment of Pierce's Disease

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Goutam (Santa Fe, NM)

    2008-10-07

    Chimeric anti-microbial proteins, compositions, and methods for the therapeutic and prophylactic treatment of plant diseases caused by the bacterial pathogen Xylella fastidiosa are provided. The anti-microbial proteins of the invention generally comprise a surface recognition domain polypeptide, capable of binding to a bacterial membrane component, fused to a bacterial lysis domain polypeptide, capable of affecting lysis or rupture of the bacterial membrane, typically via a fused polypeptide linker. In particular, methods and compositions for the treatment or prevention of Pierce's disease of grapevines are provided. Methods for the generation of transgenic Vitus vinefera plants expressing xylem-secreted anti-microbial chimeras are also provided.

  8. On resolving the enigma of infantile amnesia.

    Science.gov (United States)

    Howe, M L; Courage, M L

    1993-03-01

    Historical and current theories of infantile amnesia are examined. To evaluate the viability of these theories, as well as the phenomenon of infantile amnesia itself, a review of memory development from birth through the preschool years is provided, including an overview of relevant perceptual and neurological maturation. In the context of this review, extant theories of infantile amnesia are shown to falter, and it is concluded that infantile amnesia is a chimera of a previously unexplored relationship between the development of a cognitive sense of self and the personalization of event memory. This hypothesis is examined in detail and discussed in the context of related developments in language and social cognition.

  9. From globally coupled maps to complex-systems biology

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Kunihiko, E-mail: kaneko@complex.c.u-tokyo.ac.jp [Research Center for Complex Systems Biology, Graduate School of Arts and Sciences, The University of Tokyo 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan)

    2015-09-15

    Studies of globally coupled maps, introduced as a network of chaotic dynamics, are briefly reviewed with an emphasis on novel concepts therein, which are universal in high-dimensional dynamical systems. They include clustering of synchronized oscillations, hierarchical clustering, chimera of synchronization and desynchronization, partition complexity, prevalence of Milnor attractors, chaotic itinerancy, and collective chaos. The degrees of freedom necessary for high dimensionality are proposed to equal the number in which the combinatorial exceeds the exponential. Future analysis of high-dimensional dynamical systems with regard to complex-systems biology is briefly discussed.

  10. erbB-2 autophosphorylation is required for mitogenic action and high-affinity substrate coupling

    DEFF Research Database (Denmark)

    Segatto, O; Lonardo, F; Helin, K;

    1992-01-01

    -mutated chimera. When expressed in NR6 cells, the EGFR/erbB-2 5P mutant was unable to deliver a sizeable mitogenic signal when activated by EGF at physiological levels. In intact cells, the 5P mutant was still able to stimulate phosphorylation of the gamma isozyme of phospholipase C (PLC-gamma), a prototype erb......B-2 substrate, although with a delayed time course, indicating that the 5P mutation decreased the affinity of the erbB-2 kinase for this substrate. This conclusion was further supported by the inability of the 5P mutant to associate with PLC-gamma in co-immunoprecipitation experiments. We infer...

  11. Selective resistance of bone marrow-derived hemopoietic progenitor cells to gliotoxin

    Energy Technology Data Exchange (ETDEWEB)

    Muellbacher, A.; Hume, D.; Braithwaite, A.W.; Waring, P.; Eichner, R.D.

    1987-06-01

    The fungal metabolite gliotoxin at low concentrations prevents mitogen stimulation of mature lymphocytes as a result of gliotoxin-induced genomic DNA degradation. Bone marrow, on the other hand, contains a subpopulation of cells resistant to gliotoxin at similar concentrations. This population includes the hemopoietic progenitor cells that grow in vitro in response to appropriate colony-stimulating factors and cells that form colonies in the spleens of lethally irradiated recipients. Gliotoxin treatment of lymph node cell-enriched bone marrow significantly delayed the onset of graft-versus-host disease in fully allogeneic bone marrow chimeras.

  12. Using opioid receptors to expand the chemogenetic and optogenetic toolbox.

    Science.gov (United States)

    Damez-Werno, Diane M; Kenny, Paul J

    2015-05-20

    In this issue of Neuron, innovative new modifications to opioid receptors are used to expand the tools available to modulate neuronal activity. Vardy et al. (2015) describe a new "DREADD" chemogenetic tool based on the inhibitory κ opioid receptor (KORD) that can be used in conjunction with already-available DREADDs. Siuda et al. (2015) report the development of "opto-MOR," a light-activatable μ opioid receptor (MOR) chimera that can be used to better understand the complexities of MOR signaling.

  13. Generative Modeling for Machine Learning on the D-Wave

    Energy Technology Data Exchange (ETDEWEB)

    Thulasidasan, Sunil [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Information Sciences Group

    2016-11-15

    These are slides on Generative Modeling for Machine Learning on the D-Wave. The following topics are detailed: generative models; Boltzmann machines: a generative model; restricted Boltzmann machines; learning parameters: RBM training; practical ways to train RBM; D-Wave as a Boltzmann sampler; mapping RBM onto the D-Wave; Chimera restricted RBM; mapping binary RBM to Ising model; experiments; data; D-Wave effective temperature, parameters noise, etc.; experiments: contrastive divergence (CD) 1 step; after 50 steps of CD; after 100 steps of CD; D-Wave (experiments 1, 2, 3); D-Wave observations.

  14. A connecting hinge represses the activity of endothelial nitric oxide synthase

    OpenAIRE

    Haque, Mohammad Mahfuzul; Panda, Koustubh; Tejero, Jesús; Aulak, Kulwant S.; Fadlalla, Mohammed Adam; Mustovich, Anthony T.; Stuehr, Dennis J

    2007-01-01

    In mammals, endothelial nitric oxide synthase (eNOS) has the weakest activity, being one-tenth and one-sixth as active as the inducible NOS (iNOS) and the neuronal NOS (nNOS), respectively. The basis for this weak activity is unclear. We hypothesized that a hinge element that connects the FMN module in the reductase domain but is shorter and of unique composition in eNOS may be involved. To test this hypothesis, we generated an eNOS chimera that contained the nNOS hinge and two mutants that e...

  15. Calcium dynamics in catecholamine-containing secretory vesicles

    OpenAIRE

    Moreno, Alfredo; Domínguez Lobatón, María Carmen; Santo Domingo, Jaime; Vay, Laura; Hernández-SanMiguel, Esther; Rizzuto, Rosario; Montero, Mayte; Álvarez, Javier

    2005-01-01

    Producción Científica We have used an aequorin chimera targeted to the membrane of the secretory granules to monitor the free [Ca2+] inside them in neurosecretory PC12 cells. More than 95% of the probe was located in a compartment with an homogeneous [Ca2+] around 40 M. Cell stimulation with either ATP, caffeine or high-K+ depolarization increased cytosolic [Ca2+] and decreased secretory granule [Ca2+] ([Ca2+]SG). Inositol-(1,4,5)- trisphosphate, cyclic ADP ribose and nicotinic a...

  16. Bap31 enhances the ER export and quality control of human class I MHC molecules

    OpenAIRE

    Ladasky, John J.; Boyle, Sarah; Seth, Malini; Li, Hewang; Pentcheva, Tsvetelina; ABE, FUMIYOSHI; Steinberg, Steven J.; Edidin, Michael

    2006-01-01

    The assembly of class I MHC molecules and their export from the endoplasmic reticulum is governed by chaperones and accessory proteins. We present evidence that the putative cargo receptor protein Bap31 participates in the transport and the quality control of human class I molecules. Transfection of the human adenocarcinoma cell line HeLa with YFP-Bap31 chimeras increased surface levels of class I in a dose-dependent manner, by as much as 3.7-fold. The increase in surface class I resulted fro...

  17. Producing fully ES cell-derived mice from eight-cell stage embryo injections.

    Science.gov (United States)

    DeChiara, Thomas M; Poueymirou, William T; Auerbach, Wojtek; Frendewey, David; Yancopoulos, George D; Valenzuela, David M

    2010-01-01

    In conventional methods for the generation of genetically modified mice, gene-targeted embryonic stem (ES) cells are injected into blastocyst-stage embryos or are aggregated with morula-stage embryos, which are then transferred to the uterus of a surrogate mother. F0 generation mice born from the embryos are chimeras composed of genetic contributions from both the modified ES cells and the recipient embryos. Obtaining a mouse strain that carries the gene-targeted mutation requires breeding the chimeras to transmit the ES cell genetic component through the germ line to the next (F1) generation (germ line transmission, GLT). To skip the chimera stage, we developed the VelociMouse method, in which injection of genetically modified ES cells into eight-cell embryos followed by maturation to the blastocyst stage and transfer to a surrogate mother produces F0 generation mice that are fully derived from the injected ES cells and exhibit a 100% GLT efficiency. The method is simple and flexible. Both male and female ES cells can be introduced into the eight-cell embryo by any method of injection or aggregation and using all ES cell and host embryo combinations from inbred, hybrid, and outbred genetic backgrounds. The VelociMouse method provides several unique opportunities for shortening project timelines and reducing mouse husbandry costs. First, as VelociMice exhibit 100% GLT, there is no need to test cross chimeras to establish GLT. Second, because the VelociMouse method permits efficient production of ES cell-derived mice from female ES cells, XO ES cell subclones, identified by screening for spontaneous loss of the Y chromosome, can be used to generate F0 females that can be bred with isogenic F0 males derived from the original targeted ES cell clone to obtain homozygous mutant mice in the F1 generation. Third, as VelociMice are genetically identical to the ES cells from which they were derived, the VelociMouse method opens up myriad possibilities for creating mice with

  18. Silencing of six hydrophobins in Cladosporium fulvum: complexities of simultaneously targeting multiple genes.

    Science.gov (United States)

    Lacroix, Hélène; Spanu, Pietro D

    2009-01-01

    In this study, we have constructed and expressed inverted repeat chimeras from the first exons of the six known hydrophobins of the fungus Cladosporium fulvum, the causal agent of tomato leaf mold. We used quantitative PCR to measure specifically the expression levels of the hydrophobins. The targeted genes are silenced to different degrees, but we also detected clear changes in the expression levels of nontargeted genes. This work highlights the difficulties that are likely to be encountered when attempting to silence more than one gene in a multigene family.

  19. Production and characterisation of recombinant forms of human pulmonary surfactant protein C (SP-C)

    DEFF Research Database (Denmark)

    Lukovic, Dunja; Plasencia, Inés; Taberner, Francisco J

    2006-01-01

    -C-derived peptides or recombinant humanized SP-C for inclusion in new preparations for therapeutic use. We describe herein the recombinant production in bacterial cultures of SP-C variants containing phenylalanines instead of the palmitoylated cysteines of the native protein, as fusions to the hydrophilic nuclease...... A (SN) from Staphylococcus aureus. The resulting chimerae were partially purified by affinity chromatography and subsequently subjected to protease digestion. The SP-C forms were recovered from the digestion mixtures by organic extraction and further purified by size exclusion chromatography. The two...

  20. Rapid obtention of stable, bioluminescent tumor cell lines using a tCD2-luciferase chimeric construct

    Directory of Open Access Journals (Sweden)

    Gourzones Claire

    2011-03-01

    Full Text Available Abstract Background Bioluminescent tumor cell lines are experimental tools of major importance for cancer investigation, especially imaging of tumors in xenografted animals. Stable expression of exogenous luciferase in tumor cells combined to systemic injection of luciferin provides an excellent signal/background ratio for external optical imaging. Therefore, there is a need to rationalize and speed up the production of luciferase-positive tumor cell lines representative of multiple tumor phenotypes. For this aim we have designed a fusion gene linking the luciferase 2 protein to the c-terminus of a truncated form of the rat CD2 protein (tCD2-luc2. To allow simultaneous assessment of the wild-type luciferase 2 in a context of tCD2 co-expression, we have made a bicistronic construct for concomitant but separate expression of these two proteins (luc2-IRES-tCD2. Both the mono- and bi-cistronic constructs were transduced in lymphoid and epithelial cells using lentiviral vectors. Results The tCD2-luc2 chimera behaves as a type I membrane protein with surface presentation of CD2 epitopes. One of these epitopes reacts with the OX34, a widely spread, high affinity monoclonal antibody. Stably transfected cells are sorted by flow cytometry on the basis of OX34 staining. In vitro and, moreover, in xenografted tumors, the tCD2-luc2 chimera retains a substantial and stable luciferase activity, although not as high as the wild-type luciferase expressed from the luc2-IRES-tCD2 construct. Expression of the tCD2-luc2 chimera does not harm cell and tumor growth. Conclusion Lentiviral transduction of the chimeric tCD2-luc2 fusion gene allows selection of cell clones with stable luciferase expression in less than seven days without antibiotic selection. We believe that it will be helpful to increase the number of tumor cell lines available for in vivo imaging and assessment of novel therapeutic modalities. On a longer term, the tCD2-luc2 chimera has the potential to

  1. The binding site for neohesperidin dihydrochalcone at the human sweet taste receptor

    OpenAIRE

    2007-01-01

    Abstract Background Differences in sweet taste perception among species depend on structural variations of the sweet taste receptor. The commercially used isovanillyl sweetener neohesperidin dihydrochalcone activates the human but not the rat sweet receptor TAS1R2+TAS1R3. Analysis of interspecies combinations and chimeras of rat and human TAS1R2+TAS1R3 suggested that the heptahelical domain of human TAS1R3 is crucial for the activation of the sweet receptor by neohesperidin dihydrochalcone. R...

  2. Development of a bipartite ecdysone-responsive gene switch for the oomycete Phytophthora infestans and its use to manipulate transcription during axenic culture and plant infection.

    Science.gov (United States)

    Gamboa-Meléndez, Heber; Judelson, Howard S

    2015-01-01

    Conditional expression systems have been proven to be useful tools for the elucidation of gene function in many taxa. Here, we report the development of the first useful inducible promoter system for an oomycete, based on an ecdysone receptor (EcR) and the ecdysone analogue methoxyfenozide. In Phytophthora infestans, the potato late blight pathogen, a monopartite transactivator containing the VP16 activation domain from herpes simplex virus, the GAL4 DNA-binding domain from yeast and the EcR receptor domain from the spruce budworm enabled high levels of expression of a β-glucuronidase (GUS) reporter gene, but unacceptable basal activity in the absence of the methoxyfenozide inducer. Greatly improved performance was obtained using a bipartite system in which transcription is activated by a heterodimer between a chimera of VP16 and the migratory locust retinoid X receptor, and a separate EcR-DNA-binding domain chimera. Transformants were obtained that exhibited >100-fold activation of the reporter by methoxyfenozide, with low basal levels of expression and induced activity approaching that of the strong ham34 promoter. Performance varied between transformants, probably as a result of position effects. The addition of methoxyfenozide enabled strong induction during hyphal growth, zoosporogenesis and colonization of tomato. No significant effects of the inducer or transactivators on growth, development or pathogenicity were observed. The technology should therefore be a useful addition to the arsenal of methods for the study of oomycete plant pathogens.

  3. Designing the lipid raft marker protein for synaptic vesicles

    Institute of Scientific and Technical Information of China (English)

    Lv Jihua; Sui Senfang

    2009-01-01

    Lipid rafts are cholesterol-enriched microdomains and implicated in many essential physiological activities such as the neurotransmitter release. Many studies have been carried out on the function of rafts in the plasma membranes, whereas little is known about the information of such microdomains in subcellular compartments especially synaptic vesicles (SVs). In the well-studied plasma membranes, several proteins have been recognized as raft markers, which are used to label or trace rafts. But the raft marker protein on SVs has not been identified yet. Although some SV proteins, including VAMP and CPE, have been found in raft fractions, they cannot be used as markers due to their low abundance in rafts. In this work, we designed several chimera proteins and tested their characteristics for using as SV raft makers. First, we detected whether they located in SVs, and then the chimeras exhibiting the better localization in SVs were further examined for their enrichment in raft using detergent treatment and gradient density floatation analysis. Our results indicate that one of the chimeric proteins is primarily located in SVs and distributed in raft microdomains, which strongly suggests that it could be served as a raft marker for SVs.

  4. The conserved dileucine- and tyrosine-based motifs in MLV and MPMV envelope glycoproteins are both important to regulate a common Env intracellular trafficking

    Directory of Open Access Journals (Sweden)

    Lopez-Vergès Sandra

    2006-09-01

    Full Text Available Abstract Background Retrovirus particles emerge from the assembly of two structural protein components, Gag that is translated as a soluble protein in the cytoplasm of the host cells, and Env, a type I transmembrane protein. Because both components are translated in different intracellular compartments, elucidating the mechanisms of retrovirus assembly thus requires the study of their intracellular trafficking. Results We used a CD25 (Tac chimera-based approach to study the trafficking of Moloney murine leukemia virus and Mason-Pfizer monkey virus Env proteins. We found that the cytoplasmic tails (CTs of both Env conserved two major signals that control a complex intracellular trafficking. A dileucine-based motif controls the sorting of the chimeras from the trans-Golgi network (TGN toward endosomal compartments. Env proteins then follow a retrograde transport to the TGN due to the action of a tyrosine-based motif. Mutation of either motif induces the mis-localization of the chimeric proteins and both motifs are found to mediate interactions of the viral CTs with clathrin adaptors. Conclusion This data reveals the unexpected complexity of the intracellular trafficking of retrovirus Env proteins that cycle between the TGN and endosomes. Given that Gag proteins hijack endosomal host proteins, our work suggests that the endosomal pathway may be used by retroviruses to ensure proper encountering of viral structural Gag and Env proteins in cells, an essential step of virus assembly.

  5. Insights into the dual activity of SIVmac239 Vif against human and African green monkey APOBEC3G.

    Directory of Open Access Journals (Sweden)

    Ritu Gaur

    Full Text Available Human immunodeficiency virus type 1 (HIV-1 Vif is essential for viral evasion of the host antiviral protein APOBEC3G (APO3G. The Vif protein from a distantly related African green monkey (Agm simian immunodeficiency virus (SIVagm is unable to suppress the antiviral activity of human APO3G but is active against Agm APO3G. SIVmac Vif on the other hand, possesses antiviral activity against both human and Agm APO3G. In this study, we were interested in mapping domains in SIVmac Vif that are responsible for its dual activity against human and Agm APO3G. We constructed a series of Vif chimeras by swapping domains in SIVmac Vif with equivalent regions from SIVagm Vif and determined their activity against human and Agm APO3G. We found that replacing any region in SIVmac Vif by corresponding fragments from SIVagm Vif only moderately reduced the activity of the chimeras against Agm APO3G but in all cases resulted in a severe loss of activity against human APO3G. These results suggest that the domains in SIVmac Vif required for targeting human and Agm APO3G are distinct and cannot be defined as linear amino acid motifs but rather appear to depend on the overall structure of full-length SIVmac Vif.

  6. Soil clone library analyses to evaluate specificity and selectivity of PCR primers targeting fungal 18S rDNA for denaturing-gradient gel electrophoresis (DGGE).

    Science.gov (United States)

    Takada Hoshino, Yuko; Morimoto, Sho

    2010-01-01

    We evaluated the fungal specificity and detection bias of four fungal 18S rRNA gene (18S rDNA) primer sets for denaturing-gradient gel electrophoresis (DGGE). We constructed and compared clone libraries amplified from upland and paddy field soils with each primer set (1, NS1/GCFung; 2, FF390/FR1-GC; 3, NS1/FR1-GC; and 4, NS1/EF3 for the first PCR and NS1/FR1-GC for the second PCR). Primer set 4 (for nested PCR) showed the highest specificity for fungi but biased specific sequences. Sets 1, 2, and 3 (for single PCR) amplified non-fungal eukaryotic sequences (from 7 to 16% for upland soil and from 20 to 31% for paddy field soil) and produced libraries with similar distributions of fungal 18S rDNA sequences at both the phylum and the class level. Set 2 tended to amplify more diverse fungal sequences, maintaining higher specificity for fungi. In addition, clone analyses revealed differences among primer sets in the frequency of chimeras. In upland field soil, the libraries amplified with primer sets 3 and 4, which targeted long fragments, contained many chimeric 18S rDNA sequences (18% and 48%, respectively), while the libraries obtained with sets 1 and 2, which targeted short fragments, contained fewer chimeras (5% and 10%, respectively).

  7. Sequence recombination and conservation of Varroa destructor virus-1 and deformed wing virus in field collected honey bees (Apis mellifera.

    Directory of Open Access Journals (Sweden)

    Hui Wang

    Full Text Available We sequenced small (s RNAs from field collected honeybees (Apis mellifera and bumblebees (Bombuspascuorum using the Illumina technology. The sRNA reads were assembled and resulting contigs were used to search for virus homologues in GenBank. Matches with Varroadestructor virus-1 (VDV1 and Deformed wing virus (DWV genomic sequences were obtained for A. mellifera but not B. pascuorum. Further analyses suggested that the prevalent virus population was composed of VDV-1 and a chimera of 5'-DWV-VDV1-DWV-3'. The recombination junctions in the chimera genomes were confirmed by using RT-PCR, cDNA cloning and Sanger sequencing. We then focused on conserved short fragments (CSF, size > 25 nt in the virus genomes by using GenBank sequences and the deep sequencing data obtained in this study. The majority of CSF sites confirmed conservation at both between-species (GenBank sequences and within-population (dataset of this study levels. However, conserved nucleotide positions in the GenBank sequences might be variable at the within-population level. High mutation rates (Pi>10% were observed at a number of sites using the deep sequencing data, suggesting that sequence conservation might not always be maintained at the population level. Virus-host interactions and strategies for developing RNAi treatments against VDV1/DWV infections are discussed.

  8. Complex ordering in spin networks: Critical role of adaptation rate for dynamically evolving interactions

    Science.gov (United States)

    Pathak, Anand; Sinha, Sitabhra

    2015-09-01

    Many complex systems can be represented as networks of dynamical elements whose states evolve in response to interactions with neighboring elements, noise and external stimuli. The collective behavior of such systems can exhibit remarkable ordering phenomena such as chimera order corresponding to coexistence of ordered and disordered regions. Often, the interactions in such systems can also evolve over time responding to changes in the dynamical states of the elements. Link adaptation inspired by Hebbian learning, the dominant paradigm for neuronal plasticity, has been earlier shown to result in structural balance by removing any initial frustration in a system that arises through conflicting interactions. Here we show that the rate of the adaptive dynamics for the interactions is crucial in deciding the emergence of different ordering behavior (including chimera) and frustration in networks of Ising spins. In particular, we observe that small changes in the link adaptation rate about a critical value result in the system exhibiting radically different energy landscapes, viz., smooth landscape corresponding to balanced systems seen for fast learning, and rugged landscapes corresponding to frustrated systems seen for slow learning.

  9. Pathogenic mechanisms of Acute Graft versus Host Disease

    Directory of Open Access Journals (Sweden)

    Ferrara James L.M.

    2002-01-01

    Full Text Available Graft-versus-host-disease (GVHD is the major complication of allogeneic Bone Marrow Transplant (BMT. Older BMT recipients are a greater risk for acute GVHD after allogeneic BMT, but the causes of this association are poorly understood. Using well-characterized murine BMT models we have explored the mechanisms of increased GVHD in older mice. GVHD mortality and morbidity, and pathologic and biochemical indices were all worse in old recipients. Donor T cell responses were significantly increased in old recipients both in vivo and in vitro when stimulated by antigen-presenting cells (APCs from old mice. In a haploidential GVHD model, CD4+ donor T cells mediated more severe GVHD in old mice. We confirmed the role of aged APCs in GVHD using bone marrow chimera recipient created with either old or young bone marrow. APCs from these mice also stimulated greater responses from allogeneic cells in vitro. In a separate set of experiments we evaluated whether alloantigen expression on host target epithelium is essential for tissue damage induced by GVHD. Using bone marrow chimeras recipients in which either MHC II or MHC I alloantigen was expressed only on APCs, we found that acute GVHD does not require alloantigen expression on host target epithelium and that neutralization of tumor necrosis factor-alpha and interleukin-1 prevents acute GVHD. These results pertain to CD4-mediated GVHD and to a lesser extent in CD8-mediated GVHD, and confirm the central role of most APCs as well as inflammatory cytokines.

  10. Sequence recombination and conservation of Varroa destructor virus-1 and deformed wing virus in field collected honey bees (Apis mellifera).

    Science.gov (United States)

    Wang, Hui; Xie, Jiazheng; Shreeve, Tim G; Ma, Jinmin; Pallett, Denise W; King, Linda A; Possee, Robert D

    2013-01-01

    We sequenced small (s) RNAs from field collected honeybees (Apis mellifera) and bumblebees (Bombuspascuorum) using the Illumina technology. The sRNA reads were assembled and resulting contigs were used to search for virus homologues in GenBank. Matches with Varroadestructor virus-1 (VDV1) and Deformed wing virus (DWV) genomic sequences were obtained for A. mellifera but not B. pascuorum. Further analyses suggested that the prevalent virus population was composed of VDV-1 and a chimera of 5'-DWV-VDV1-DWV-3'. The recombination junctions in the chimera genomes were confirmed by using RT-PCR, cDNA cloning and Sanger sequencing. We then focused on conserved short fragments (CSF, size > 25 nt) in the virus genomes by using GenBank sequences and the deep sequencing data obtained in this study. The majority of CSF sites confirmed conservation at both between-species (GenBank sequences) and within-population (dataset of this study) levels. However, conserved nucleotide positions in the GenBank sequences might be variable at the within-population level. High mutation rates (Pi>10%) were observed at a number of sites using the deep sequencing data, suggesting that sequence conservation might not always be maintained at the population level. Virus-host interactions and strategies for developing RNAi treatments against VDV1/DWV infections are discussed.

  11. Cloning of ribosomal ITS PCR products creates frequent, non-random chimeric sequences – a test involving heterozygotes between Gymnopus dichrous taxa I and II

    Directory of Open Access Journals (Sweden)

    Karen W. Hughes

    2015-06-01

    Full Text Available Gymnopus dichrous exists in the southern Appalachians (USA as two distinct entities with essentially identical nuclear ribosomal ITS1 sequences but differing ITS2 and LSU sequences (for convenience, called G. dichrous I and II. F1 ITS heterozygotes between the two are routinely collected from nature. Cloning of ITS PCR products from F1 heterozygotes produced sequences of both parental haplotypes but also numerous chimeric sequences (21.9%. The location of template switching was non-random leading to recovery of the same chimera several times and the chimeric region varied from 45bp to 300bp. By comparison, single-basidiospore isolates from heterozygote F1 fruitbodies showed no recombinant haplotypes within the ITS + LSU span and clones derived from P1 homozygotes were identical to the P1 parent. Thus, chimeric sequences are likely an artifact of the PCR-cloning process and not a consequence of natural recombination events found in nature, nor are they due to hidden existing variation within the ribosomal repeat. Chimeras and PCR-induced mutations are common in cloned PCR products and may result in incorrect sequence information in public databases.

  12. Identification of structural traits that increase the antimicrobial activity of a chimeric peptide of human β-defensins 2 and 3.

    Science.gov (United States)

    Spudy, Björn; Sönnichsen, Frank D; Waetzig, Georg H; Grötzinger, Joachim; Jung, Sascha

    2012-10-12

    Antimicrobial peptides participate in the first line of defence of many organisms against pathogens. In humans, the family of β-defensins plays a pivotal role in innate immunity. Two human β-defensins, β-defensin-2 and -3 (HBD2 and HBD3), show substantial sequence identity and structural similarity. However, HBD3 kills Staphylococcus (S.) aureus with a 4- to 8-fold higher efficiency compared to HBD2, whereas their activities against Escherichia (E.) coli are very similar. The generation of six HBD2/HBD3-chimeric molecules led to the identification of distinct molecular regions which mediate their divergent killing properties. One of the chimeras (chimera C3) killed both E. coli and S. aureus with an even higher efficacy compared to the wild-type molecules. Due to the broad spectrum of its antimicrobial activity against many human multidrug-resistant pathogens, this HBD2/HBD3-chimeric peptide represents a promising candidate for a new class of antibiotics. In order to investigate the structural basis of its exceptional antimicrobial activity, the peptide's tertiary structure was determined by NMR spectroscopy, which allowed its direct comparison to the published structures of HBD2 and HBD3 and the identification of the activity-increasing molecular features.

  13. Exploiting the yeast L-A viral capsid for the in vivo assembly of chimeric VLPs as platform in vaccine development and foreign protein expression.

    Directory of Open Access Journals (Sweden)

    Frank Powilleit

    Full Text Available A novel expression system based on engineered variants of the yeast (Saccharomyces cerevisiae dsRNA virus L-A was developed allowing the in vivo assembly of chimeric virus-like particles (VLPs as a unique platform for a wide range of applications. We show that polypeptides fused to the viral capsid protein Gag self-assemble into isometric VLP chimeras carrying their cargo inside the capsid, thereby not only effectively preventing proteolytic degradation in the host cell cytosol, but also allowing the expression of a per se cytotoxic protein. Carboxyterminal extension of Gag by T cell epitopes from human cytomegalovirus pp65 resulted in the formation of hybrid VLPs that strongly activated antigen-specific CD8(+ memory T cells ex vivo. Besides being a carrier for polypeptides inducing antigen-specific immune responses in vivo, VLP chimeras were also shown to be effective in the expression and purification of (i a heterologous model protein (GFP, (ii a per se toxic protein (K28 alpha-subunit, and (iii a particle-associated and fully recyclable biotechnologically relevant enzyme (esterase A. Thus, yeast viral Gag represents a unique platform for the in vivo assembly of chimeric VLPs, equally attractive and useful in vaccine development and recombinant protein production.

  14. LUCID: A Quantitative Assay of ESCRT-Mediated Cargo Sorting into Multivesicular Bodies.

    Science.gov (United States)

    Nickerson, Daniel P; Merz, Alexey J

    2015-12-01

    Endosomes are transportation nodes, mediating selective transport of soluble and transmembrane cargos to and from the Golgi apparatus, plasma membrane and lysosomes. As endosomes mature to become multivesicular bodies (MVBs), Endosomal Sorting Complexes Required for Transport (ESCRTs) selectively incorporate transmembrane cargos into vesicles that bud into the endosome lumen. Luminal vesicles and their cargoes are targeted for destruction when MVBs fuse with lysosomes. Common assays of endosomal luminal targeting, including fluorescence microscopy and monitoring of proteolytic cargo maturation, possess significant limitations. We present a quantitative assay system called LUCID (LUCiferase reporter of Intraluminal Deposition) that monitors exposure of chimeric luciferase-cargo reporters to cytosol. Luciferase-chimera signal increases when sorting to the endosome lumen is disrupted, and silencing of signal from the chimera depends upon luminal delivery of the reporter rather than proteolytic degradation. The system presents several advantages, including rapidity, microscale operation and a high degree of reproducibility that enables detection of subtle phenotypic differences. Luciferase reporters provide linear signal over an extremely broad dynamic range, allowing analysis of reporter traffic even at anemic levels of expression. Furthermore, LUCID reports transport kinetics when applied to inducible trafficking reporters.

  15. Rotation of artificial rotor axles in rotary molecular motors.

    Science.gov (United States)

    Baba, Mihori; Iwamoto, Kousuke; Iino, Ryota; Ueno, Hiroshi; Hara, Mayu; Nakanishi, Atsuko; Kishikawa, Jun-Ichi; Noji, Hiroyuki; Yokoyama, Ken

    2016-10-04

    F1- and V1-ATPase are rotary molecular motors that convert chemical energy released upon ATP hydrolysis into torque to rotate a central rotor axle against the surrounding catalytic stator cylinder with high efficiency. How conformational change occurring in the stator is coupled to the rotary motion of the axle is the key unknown in the mechanism of rotary motors. Here, we generated chimeric motor proteins by inserting an exogenous rod protein, FliJ, into the stator ring of F1 or of V1 and tested the rotation properties of these chimeric motors. Both motors showed unidirectional and continuous rotation, despite no obvious homology in amino acid sequence between FliJ and the intrinsic rotor subunit of F1 or V1 These results showed that any residue-specific interactions between the stator and rotor are not a prerequisite for unidirectional rotation of both F1 and V1 The torque of chimeric motors estimated from viscous friction of the rotation probe against medium revealed that whereas the F1-FliJ chimera generates only 10% of WT F1, the V1-FliJ chimera generates torque comparable to that of V1 with the native axle protein that is structurally more similar to FliJ than the native rotor of F1 This suggests that the gross structural mismatch hinders smooth rotation of FliJ accompanied with the stator ring of F1.

  16. Amino acid substitution converts WEREWOLF function from an activator to a repressor of Arabidopsis non-hair cell development.

    Science.gov (United States)

    Tominaga-Wada, Rumi; Nukumizu, Yuka; Wada, Takuji

    2012-02-01

    Root hair cell or non-hair cell fate determination in Arabidopsis thaliana root epidermis is model system for plant cell development. Two types of MYB transcription factors, the R2R3-type MYB, WEREWOLF (WER), and an R3-type MYB, CAPRICE (CPC), are involved in this cell fate determination process. To study the molecular basis of this process, we analyzed the functional relationship of WER and CPC. WER-CPC chimeric constructs were made from WER where all or parts of the MYB R3 region were replaced with the corresponding regions from CPC R3, and the constructs were introduced into the cpc-2 mutant. Although, the WER gene did not rescue the cpc-2 mutant 'small number of root hairs' phenotype, the WER-CPC chimera with two amino acids substitution (WC6) completely rescued the cpc-2 mutant phenotype. Furthermore, the WER-CPC chimera with 37 amino acids substitution (WC5) excessively rescued the cpc-2 mutant and induced 2.5 times more root hairs than wild-type. Consistent with this phenotype, GL2 gene expression was strongly reduced in WC5 in a cpc-2 background. Our results suggest that swapping at least two amino acids is sufficient to convert WER to CPC function. Therefore, these key residues may have strongly contributed to the selection of these important functions over evolution.

  17. Novel fusion of MYST/Esa1-associated factor 6 and PHF1 in endometrial stromal sarcoma.

    Directory of Open Access Journals (Sweden)

    Ioannis Panagopoulos

    Full Text Available Rearrangement of chromosome band 6p21 is recurrent in endometrial stromal sarcoma (ESS and targets the PHF1 gene. So far, PHF1 was found to be the 3' partner in the JAZF1-PHF1 and EPC1-PHF1 chimeras but since the 6p21 rearrangements involve also other chromosomal translocation partners, other PHF1-fusions seem likely. Here, we show that PHF1 is recombined with a novel fusion partner, MEAF6 from 1p34, in an ESS carrying a t(1;6(p34;p21 translocation as the sole karyotypic anomaly. 5'-RACE, RT-PCR, and sequencing showed the presence of an MEAF6-PHF1 chimera in the tumor with exon 5 of MEAF6 being fused in-frame to exon 2 of PHF1 so that the entire PHF1 coding region becomes the 3' terminal part of the MEAF6-PHF1 fusion. The predicted fusion protein is composed of 750 amino acids and contains the histone acetyltransferase subunit NuA4 domain of MEAF6 and the tudor, PHD zinc finger, and MTF2 domains of PHF1. Although the specific functions of the MEAF6 and PHF1 proteins and why they are targeted by a neoplasia-specific gene fusion are not directly apparent, it seems that rearrangement of genes involved in acetylation (EPC1, MEAF6 and methylation (PHF1, resulting in aberrant gene expression, is a common theme in ESS pathogenesis.

  18. Modification of the GS LT Paired-end Library Protocol for Constructing Longer Insert Size Libraries

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Ze; Peng, Ze; Hamilton, Matthew; Ting, Sara; Tu, Hank; Goltsman, Eugene; Lapidus, Alla; Lucas, Susan; Cheng, Jan-Fang

    2008-05-22

    Paired-end library sequencing has been proven useful in scaffold construction during de novo assembly of genomic sequences. The ability of generating mate pairs with 8 Kb or greater insert sizes is especially important for genomes containing long repeats. While the current 454 GS LT Paired-end library preparation protocol can successfully construct libraries with 3 Kb insert size, it fails to generate longer insert sizes because the protocol is optimized to purify shorter fragments. We have made several changes in the protocol in order to increase the fragment length. These changes include the use of Promega column to increase the yield of large size DNA fragments, two gel purification steps to remove contaminated short fragments, and a large reaction volume in the circularization step to decrease the formation of chimeras. We have also made additional changes in the protocol to increase the overall quality of the libraries. The quality of the libraries are measured by a set of metrics, which include levels of redundant reads, linker positive, linker negative, half linker reads, and driver DNA contamination, and read length distribution, were used to measure the primary quality of these libraries. We have also assessed the quality of the resulted mate pairs including levels of chimera, distribution of insert sizes, and genome coverage after the assemblies are completed. Our data indicated that all these changes have improved the quality of the longer insert size libraries.

  19. Virtual Data in CMS Analysis

    CERN Document Server

    Arbree, A; Bourilkov, D; Cavanaugh, R J; Graham, G; Rodríguez, J; Wilde, M; Zhao, Y

    2003-01-01

    The use of virtual data for enhancing the collaboration between large groups of scientists is explored in several ways: - by defining ``virtual'' parameter spaces which can be searched and shared in an organized way by a collaboration of scientists in the course of their analysis - by providing a mechanism to log the provenance of results and the ability to trace them back to the various stages in the analysis of real or simulated data - by creating ``check points'' in the course of an analysis to permit collaborators to explore their own analysis branches by refining selections, improving the signal to background ratio, varying the estimation of parameters, etc. - by facilitating the audit of an analysis and the reproduction of its results by a different group, or in a peer review context. We describe a prototype for the analysis of data from the CMS experiment based on the virtual data system Chimera and the object-oriented data analysis framework ROOT. The Chimera system is used to chain together several s...

  20. Virtual data in CMS analysis

    Energy Technology Data Exchange (ETDEWEB)

    A. Arbree et al.

    2003-10-01

    The use of virtual data for enhancing the collaboration between large groups of scientists is explored in several ways: by defining ''virtual'' parameter spaces which can be searched and shared in an organized way by a collaboration of scientists in the course of their analysis; by providing a mechanism to log the provenance of results and the ability to trace them back to the various stages in the analysis of real or simulated data; by creating ''check points'' in the course of an analysis to permit collaborators to explore their own analysis branches by refining selections, improving the signal to background ratio, varying the estimation of parameters, etc.; by facilitating the audit of an analysis and the reproduction of its results by a different group, or in a peer review context. We describe a prototype for the analysis of data from the CMS experiment based on the virtual data system Chimera and the object-oriented data analysis framework ROOT. The Chimera system is used to chain together several steps in the analysis process including the Monte Carlo generation of data, the simulation of detector response, the reconstruction of physics objects and their subsequent analysis, histogramming and visualization using the ROOT framework.

  1. Quantum Optimization of Fully Connected Spin Glasses

    Science.gov (United States)

    Venturelli, Davide; Mandrà, Salvatore; Knysh, Sergey; O'Gorman, Bryan; Biswas, Rupak; Smelyanskiy, Vadim

    2015-07-01

    Many NP-hard problems can be seen as the task of finding a ground state of a disordered highly connected Ising spin glass. If solutions are sought by means of quantum annealing, it is often necessary to represent those graphs in the annealer's hardware by means of the graph-minor embedding technique, generating a final Hamiltonian consisting of coupled chains of ferromagnetically bound spins, whose binding energy is a free parameter. In order to investigate the effect of embedding on problems of interest, the fully connected Sherrington-Kirkpatrick model with random ±1 couplings is programmed on the D-Wave TwoTM annealer using up to 270 qubits interacting on a Chimera-type graph. We present the best embedding prescriptions for encoding the Sherrington-Kirkpatrick problem in the Chimera graph. The results indicate that the optimal choice of embedding parameters could be associated with the emergence of the spin-glass phase of the embedded problem, whose presence was previously uncertain. This optimal parameter setting allows the performance of the quantum annealer to compete with (and potentially outperform, in the absence of analog control errors) optimized simulated annealing algorithms.

  2. The chimeric transcript RUNX1-GLRX5: a biomarker for good postoperative prognosis in Stage IA non-small-cell lung cancer.

    Science.gov (United States)

    Ishikawa, Rie; Amano, Yosuke; Kawakami, Masanori; Sunohara, Mitsuhiro; Watanabe, Kousuke; Kage, Hidenori; Ohishi, Nobuya; Yatomi, Yutaka; Nakajima, Jun; Fukayama, Masashi; Nagase, Takahide; Takai, Daiya

    2016-02-01

    Stage IA non-small-cell lung cancer cases have been recognized as having a low risk of relapse; however, occasionally, relapse may occur. To predict clinical outcome in Stage IA non-small-cell lung cancer patients, we searched for chimeric transcripts that can be used as biomarkers and identified a novel chimeric transcript, RUNX1-GLRX5, comprising RUNX1, a transcription factor, and GLRX5. This chimera was detected in approximately half of the investigated Stage IA non-small-cell lung cancer patients (44/104 cases, 42.3%). Although there was no significant difference in the overall survival rate between RUNX1-GLRX5-positive and -negative cases (P = 0.088), a significantly lower relapse rate was observed in the RUNX1-GLRX5-positive cases (P = 0.039), indicating that this chimera can be used as a biomarker for good prognosis in Stage IA patients. Detection of the RUNX1-GLRX5 chimeric transcript may therefore be useful for the determination of a postoperative treatment plan for Stage IA non-small-cell lung cancer patients.

  3. Isolation and differentiation of medaka embryonic stem cells.

    Science.gov (United States)

    Hong, Yunhan; Schartl, Manfred

    2006-01-01

    Medaka is a small laboratory fish that daily produces eggs easily controllable by light cycles. This fish represents a unique lower vertebrate compared to mammals, in which embryonic stem (ES) cell lines can be derived from midblastula embryos (MBEs). Like mouse ES cells, medaka ES cells most resemble the totipotent embryonic cells at the blastula stage. Medaka ES cells retain a diploid karyotype, pluripotency in vitro, and chimera competence in vivo. They give rise to high efficiencies of transient and stable gene transfer and maintain their pluripotency after long-term drug selection for transgene integration. They can also be directed to differentiate into particular cell types. Medaka is the most distantly related vertebrate to mammals, and its ES cell lines provide an ideal reference to mammalian ES cells for the molecular analysis of stemness. More important, medaka ES cell lines on their own offer an excellent tool for studying stem cell biology in vitro and in vivo because production and observation of ES-derived chimeras as well as phenotypic analyses are very easy because of its external, transparent, and temperature-adjustable embryology.

  4. Cheating by exploitation of developmental prestalk patterning in Dictyostelium discoideum.

    Directory of Open Access Journals (Sweden)

    Anupama Khare

    2010-02-01

    Full Text Available The cooperative developmental system of the social amoeba Dictyostelium discoideum is susceptible to exploitation by cheaters-strains that make more than their fair share of spores in chimerae. Laboratory screens in Dictyostelium have shown that the genetic potential for facultative cheating is high, and field surveys have shown that cheaters are abundant in nature, but the cheating mechanisms are largely unknown. Here we describe cheater C (chtC, a strong facultative cheater mutant that cheats by affecting prestalk differentiation. The chtC gene is developmentally regulated and its mRNA becomes stalk-enriched at the end of development. chtC mutants are defective in maintaining the prestalk cell fate as some of their prestalk cells transdifferentiate into prespore cells, but that defect does not affect gross developmental morphology or sporulation efficiency. In chimerae between wild-type and chtC mutant cells, the wild-type cells preferentially give rise to prestalk cells, and the chtC mutants increase their representation in the spore mass. Mixing chtC mutants with other cell-type proportioning mutants revealed that the cheating is directly related to the prestalk-differentiation propensity of the victim. These findings illustrate that a cheater can victimize cooperative strains by exploiting an established developmental pathway.

  5. Tratamento de mandioca pela colchicina: II. formas poliplóides obtidas

    Directory of Open Access Journals (Sweden)

    E. A. Graner

    1942-02-01

    Full Text Available The methods used in obtaining polyploid cassava (Manihot utilissima Pohl by colchicine treatment were described in detail. Two solutions of colchicine were tried, one at 0.5% and other at 1.0%, both giving identical results in producing many altered plants. The chromosome number of the altered plants was determined and [a correlation between chromosome duplication and increase of the major diameter of stomata was found. Size of stomata in cassava serves to identify poliploids individuals if the plant produced by treatment is not a chimera, a very frequent event in producing polyploid cassava by colchicine. It was emphasized that the plants obtained by treatment were a type of chimera, with the aerial part polyploid and the subterranean base diploid. The development of polyploid individuals obtained from the polyploid aerial part of the treated was analyzed. A comparison between the tetraploid and the diploid control plants was made, the octoploid plant being too slow in development. There are many groups of polivalents in the first meiotic metaphase of the autopoly-ploid individuals obtained. By an analysis of the polen grains it was assumed that the diploid plant may be a structural hybrid. The production of the tetraploid plants was computed preliminarly, other detailed experiments involving spacing being necessary for estimating the commercial production,, since the diploid produces more branched plants than the tetraploid ones.

  6. Successful treatment of murine beta-thalassemia intermedia by transfer of the human beta-globin gene.

    Science.gov (United States)

    May, Chad; Rivella, Stefano; Chadburn, Amy; Sadelain, Michel

    2002-03-15

    The beta-thalassemias are caused by more than 200 mutations that reduce or abolish beta-globin production. The severity of the resulting anemia can lead to lifelong transfusion dependency. A genetic treatment based on globin gene transfer would require that transgene expression be erythroid specific, elevated, and sustained over time. We report here that long-term synthesis of chimeric hemoglobin (mualpha(2):hubeta(A)(2)) could be achieved in mice with beta-thalassemia intermedia following engraftment with bone marrow cells transduced with a lentiviral vector encoding the human beta-globin gene. In the absence of any posttransduction selection, the treated chimeras exhibit durably increased hemoglobin levels without diminution over 40 weeks. Ineffective erythropoiesis and extramedullary hematopoiesis (EMH) regress, as reflected by normalization of spleen size, architecture, hematopoietic colony formation, and disappearance of liver EMH. These findings establish that a sustained increase of 3 to 4 g/dL hemoglobin is sufficient to correct ineffective erythropoiesis. Hepatic iron accumulation is markedly decreased in 1-year-old chimeras, indicating persistent protection from secondary organ damage. These results demonstrate for the first time that viral-mediated globin gene transfer in hematopoietic stem cells effectively treats a severe hemoglobin disorder.

  7. Evolving approaches of hematopoietic stem cell-based therapies to induce tolerance to organ transplants: the long road to tolerance.

    Science.gov (United States)

    Leventhal, J; Miller, J; Abecassis, M; Tollerud, D J; Ildstad, S T

    2013-01-01

    The immunoregulatory properties of hematopoietic stem cells (HSCs) have been recognized for more than 60 years, beginning in 1945, when Owen reported that genetically disparate freemartin cattle sharing a common placenta were red blood cell chimeras. In 1953, Billingham, Brent, and Medawar demonstrated that murine neonatal chimeras prepared by infusion of donor-derived hematopoietic cells exhibited donor-specific tolerance to skin allografts. Various approaches using HSCs in organ transplantation have gradually brought closer to reality the dream of inducing donor-specific tolerance in organ transplant recipients. Several hurdles needed to be overcome, especially the risk of graft-versus-host disease (GVHD), the toxicity of ablative conditioning, and the need for close donor-recipient matching. For wide acceptance, HSC therapy must be safe and reproducible in mismatched donor-recipient combinations. Discoveries in other disciplines have often unexpectedly and synergistically contributed to progress in this area. This review presents a historic perspective of the quest for tolerance in organ transplantation, highlighting current clinical approaches.

  8. The you gene encodes an EGF-CUB protein essential for Hedgehog signaling in zebrafish.

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    Ian G Woods

    2005-03-01

    Full Text Available Hedgehog signaling is required for many aspects of development in vertebrates and invertebrates. Misregulation of the Hedgehog pathway causes developmental abnormalities and has been implicated in certain types of cancer. Large-scale genetic screens in zebrafish have identified a group of mutations, termed you-class mutations, that share common defects in somite shape and in most cases disrupt Hedgehog signaling. These mutant embryos exhibit U-shaped somites characteristic of defects in slow muscle development. In addition, Hedgehog pathway mutations disrupt spinal cord patterning. We report the positional cloning of you, one of the original you-class mutations, and show that it is required for Hedgehog signaling in the development of slow muscle and in the specification of ventral fates in the spinal cord. The you gene encodes a novel protein with conserved EGF and CUB domains and a secretory pathway signal sequence. Epistasis experiments support an extracellular role for You upstream of the Hedgehog response mechanism. Analysis of chimeras indicates that you mutant cells can appropriately respond to Hedgehog signaling in a wild-type environment. Additional chimera analysis indicates that wild-type you gene function is not required in axial Hedgehog-producing cells, suggesting that You is essential for transport or stability of Hedgehog signals in the extracellular environment. Our positional cloning and functional studies demonstrate that You is a novel extracellular component of the Hedgehog pathway in vertebrates.

  9. Immunoreactivity evaluation of a new recombinant chimeric protein against Brucella in the murine model

    Directory of Open Access Journals (Sweden)

    Abbas Abdollahi

    2016-10-01

    Full Text Available Background and Objectives: Brucellosis is an important health problem in developing countries and no vaccine is available for the prevention of infection in humans. Because of clinically infectious diseases and their economic consequences in human and animals, designing a proper vaccine against Brucella is desirable. In this study, we evaluated the immune responses induced by a designed recombinant chimera protein in murine model.Materials and Methods: Three immunodominant antigens of Brucella have been characterized as potential immunogenic and protective antigens including: trigger factor (TF, Omp31 and Bp26 were fused together by EAAAK linkers to produce a chimera (structure were designed in silico, which was synthesized, cloned, and expressed in E. coli BL21 (DE3. The purification of recombinant protein was performed using Ni-NTA agarose. SDS-PAGE and anti-His antibody was used for confirmation purified protein (Western blot. BALB/c immunization was performed by purified protein and adjuvant, and sera antibody levels were measured by ELISA. otted.Results: SDS-PAGE and Western blotting results indicated the similarity of in silico designing and in vitro experiments. ELISA result proved that the immunized sera of mice contain high levels of antibodies (IgG against recombinant chimeric protein.Conclusion: The recombinant chimeric protein could be a potential antigen candidate for the development of a subunit vaccine against Brucella. Keywords: Brucella, Vaccine, Immunity, Recombinant

  10. Muscular derivatives of the cranialmost somites revealed by long-term fate mapping in the Mexican axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Piekarski, Nadine; Olsson, Lennart

    2007-01-01

    The fate of single somites has not been analyzed from a comparative perspective with modern cell-marking methods. Most of what we know is based on work using quail-chick chimeras. Consequently, to what degree cell fate has been conserved despite the anatomical differences among vertebrates is unknown. We have analyzed the cell fate of the cranialmost somites, with the focus on somite two, in the Mexican axolotl (Ambystoma mexicanum). Somite cells were marked by injection of dextran-fluorescein and detected using immunofluorescence after 2 months of development in paraffin sections. Our data confirm and extend earlier studies based on classical histology in salamanders. We show that somite two contributes to different muscles, skeletal elements, and connective tissues of the head and cranial trunk region. Cells from somites two and three migrate latero-ventrally and contribute to the hypobranchial muscles mm. geniohyoideus and rectus cervicis. We provide evidence that the specific formation of the hypobranchial musculature from ventral processes of the somites might be variable in different classes of vertebrates. We further demonstrate that mm. cucullaris and dilatator laryngis, which were earlier thought to have a branchial origin, arise from somitic material in a manner very similar to the findings in quail-chick chimeras. Our findings indicate that the pattern of somitic derivatives is highly conserved within tetrapods.

  11. Formation of chimeric genes by copy-number variation as a mutational mechanism in schizophrenia.

    Science.gov (United States)

    Rippey, Caitlin; Walsh, Tom; Gulsuner, Suleyman; Brodsky, Matt; Nord, Alex S; Gasperini, Molly; Pierce, Sarah; Spurrell, Cailyn; Coe, Bradley P; Krumm, Niklas; Lee, Ming K; Sebat, Jonathan; McClellan, Jon M; King, Mary-Claire

    2013-10-03

    Chimeric genes can be caused by structural genomic rearrangements that fuse together portions of two different genes to create a novel gene. We hypothesize that brain-expressed chimeras may contribute to schizophrenia. Individuals with schizophrenia and control individuals were screened genome wide for copy-number variants (CNVs) that disrupted two genes on the same DNA strand. Candidate events were filtered for predicted brain expression and for frequency genes in localization, regulation, or function. Subcellular localizations of DNAJA2-NETO2 and MAP3K3-DDX42 differed from their parent genes. On the basis of the expression profile of the MATK promoter, MATK-ZFR2 is likely to be far more highly expressed in the brain during development than the ZFR2 parent gene. MATK-ZFR2 includes a ZFR2-derived isoform that we demonstrate localizes preferentially to neuronal dendritic branch sites. These results suggest that the formation of chimeric genes is a mechanism by which CNVs contribute to schizophrenia and that, by interfering with parent gene function, chimeras may disrupt critical brain processes, including neurogenesis, neuronal differentiation, and dendritic arborization.

  12. Functional Expression of Aquaporin-2 Tagged with Photoconvertible Fluorescent Protein in mpkCCD Cells

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    Kay-Pong Yip

    2015-05-01

    Full Text Available Background: Vasopressin induced trafficking of aquaporin-2 (AQP2 containing vesicles has been studied in kidney cell lines using conventional fluorescent proteins as tags. However, trafficking of fluorescent tagged AQP2, which resembles the vectorial translocation of native AQP2 from cytoplasm to apical membrane has not been demonstrated at real time. Using a photoconvertible fluorescent protein tag on AQP2 might allow the simultaneous tracking of two separate populations of AQP2 vesicle after subcellular local photoconversion. Methods: A spacer was used to link a photoconvertible fluorescent protein (mEos2 to the amino-terminus of AQP2. The DNA constructs were expressed in mpkCCD cells. The trafficking of chimeric protein was visualized with high speed confocal microscopy in 4 dimensions. Results: Chimeric AQP2 expressed in mpkCCD cell conferred osmotic water permeability to the cells. Subcellular photoconversion with a 405 nm laser pulse converted green chimeras to red chimeras locally. Forskolin stimulation triggered chimeric AQP2 to translocate from acidic organelles to apical plasma membrane. By serendipity, the rate of apical accumulation was found to increase when mEos2 was tagged to the carboxyl-terminus in at least one of the AQP2 molecules within the tetramer. Conclusion: Functional photoconvertible chimeric AQP2 was successfully expressed in mpkCCD cells, in which forskolin induced apical trafficking and accumulation of chimeric AQP2. The proof-of-concept to monitor two populations of AQP2 vesicle simultaneously was demonstrated.

  13. A chimeric scorpion alpha-toxin displays de novo electrophysiological properties similar to those of alpha-like toxins.

    Science.gov (United States)

    Bouhaouala-Zahar, Balkiss; Benkhalifa, Rym; Srairi, Najet; Zenouaki, Ilhem; Ligny-Lemaire, Caroline; Drevet, Pascal; Sampieri, François; Pelhate, Marcel; El Ayeb, Mohamed; Ménez, André; Karoui, Habib; Ducancel, Frédéric

    2002-06-01

    BotXIV and LqhalphaIT are two structurally related long chain scorpion alpha-toxins that inhibit sodium current inactivation in excitable cells. However, while LqhalphaIT from Leiurus quinquestriatus hebraeus is classified as a true and strong insect alpha-toxin, BotXIV from Buthus occitanus tunetanus is characterized by moderate biological activities. To assess the possibility that structural differences between these two molecules could reflect the localization of particular functional topographies, we compared their sequences. Three structurally deviating segments located in three distinct and exposed loops were identified. They correspond to residues 8-10, 19-22, and 38-43. To evaluate their functional role, three BotXIV/LqhalphaIT chimeras were designed by transferring the corresponding LqhalphaIT sequences into BotXIV. Structural and antigenic characterizations of the resulting recombinant chimera show that BotXIV can accommodate the imposed modifications, confirming the structural flexibility of that particular alpha/beta fold. Interestingly, substitution of residues 8-10 yields to a new electrophysiological profile of the corresponding variant, partially comparable to that one of alpha-like scorpion toxins. Taken together, these results suggest that even limited structural deviations can reflect functional diversity, and also that the structure-function relationships between insect alpha-toxins and alpha-like scorpion toxins are probably more complex than expected.

  14. Interaction between Functional Domains of Bacillus thuringiensis Insecticidal Crystal Proteins

    Science.gov (United States)

    Rang, Cécile; Vachon, Vincent; de Maagd, Ruud A.; Villalon, Mario; Schwartz, Jean-Louis; Bosch, Dirk; Frutos, Roger; Laprade, Raynald

    1999-01-01

    Interactions among the three structural domains of Bacillus thuringiensis Cry1 toxins were investigated by functional analysis of chimeric proteins. Hybrid genes were prepared by exchanging the regions coding for either domain I or domain III among Cry1Ab, Cry1Ac, Cry1C, and Cry1E. The activity of the purified trypsin-activated chimeric toxins was evaluated by testing their effects on the viability and plasma membrane permeability of Sf9 cells. Among the parental toxins, only Cry1C was active against these cells and only chimeras possessing domain II from Cry1C were functional. Combination of domain I from Cry1E with domains II and III from Cry1C, however, resulted in an inactive toxin, indicating that domain II from an active toxin is necessary, but not sufficient, for activity. Pores formed by chimeric toxins in which domain I was from Cry1Ab or Cry1Ac were slightly smaller than those formed by toxins in which domain I was from Cry1C. The properties of the pores formed by the chimeras are therefore likely to result from an interaction between domain I and domain II or III. Domain III appears to modulate the activity of the chimeric toxins: combination of domain III from Cry1Ab with domains I and II of Cry1C gave a protein which was more strongly active than Cry1C. PMID:10388684

  15. Signaling of human frizzled receptors to the mating pathway in yeast.

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    Dietmar Dirnberger

    Full Text Available Frizzled receptors have seven membrane-spanning helices and are considered as atypical G protein-coupled receptors (GPCRs. The mating response of the yeast Saccharomyces cerevisiae is mediated by a GPCR signaling system and this model organism has been used extensively in the past to study mammalian GPCR function. We show here that human Frizzled receptors (Fz1 and Fz2 can be properly targeted to the yeast plasma membrane, and that they stimulate the yeast mating pathway in the absence of added Wnt ligands, as evidenced by cell cycle arrest in G1 and reporter gene expression dependent on the mating pathway-activated FUS1 gene. Introducing intracellular portions of Frizzled receptors into the Ste2p backbone resulted in the generation of constitutively active receptor chimeras that retained mating factor responsiveness. Introducing intracellular portions of Ste2p into the Frizzled receptor backbone was found to strongly enhance mating pathway activation as compared to the native Frizzleds, likely by facilitating interaction with the yeast Galpha protein Gpa1p. Furthermore, we show reversibility of the highly penetrant G1-phase arrests exerted by the receptor chimeras by deletion of the mating pathway effector FAR1. Our data demonstrate that Frizzled receptors can functionally replace mating factor receptors in yeast and offer an experimental system to study modulators of Frizzled receptors.

  16. Signaling of human frizzled receptors to the mating pathway in yeast.

    Science.gov (United States)

    Dirnberger, Dietmar; Seuwen, Klaus

    2007-09-26

    Frizzled receptors have seven membrane-spanning helices and are considered as atypical G protein-coupled receptors (GPCRs). The mating response of the yeast Saccharomyces cerevisiae is mediated by a GPCR signaling system and this model organism has been used extensively in the past to study mammalian GPCR function. We show here that human Frizzled receptors (Fz1 and Fz2) can be properly targeted to the yeast plasma membrane, and that they stimulate the yeast mating pathway in the absence of added Wnt ligands, as evidenced by cell cycle arrest in G1 and reporter gene expression dependent on the mating pathway-activated FUS1 gene. Introducing intracellular portions of Frizzled receptors into the Ste2p backbone resulted in the generation of constitutively active receptor chimeras that retained mating factor responsiveness. Introducing intracellular portions of Ste2p into the Frizzled receptor backbone was found to strongly enhance mating pathway activation as compared to the native Frizzleds, likely by facilitating interaction with the yeast Galpha protein Gpa1p. Furthermore, we show reversibility of the highly penetrant G1-phase arrests exerted by the receptor chimeras by deletion of the mating pathway effector FAR1. Our data demonstrate that Frizzled receptors can functionally replace mating factor receptors in yeast and offer an experimental system to study modulators of Frizzled receptors.

  17. Mucosal vaccination by adenoviruses displaying reovirus sigma 1

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Eric A. [Department of Internal Medicine, Division of Infectious Diseases, Translational Immunovirology and Biodefense Program, Mayo Clinic, Rochester, MN 55902 (United States); Camacho, Zenaido T. [Department of Cell Biology, Department of Natural Sciences, Western New Mexico University, Silver City, NM 88062 (United States); Hillestad, Matthew L. [Nephrology Training Program, Mayo Clinic, Rochester, MN 55902 (United States); Crosby, Catherine M.; Turner, Mallory A.; Guenzel, Adam J.; Fadel, Hind J. [Virology and Gene Therapy Graduate Program, Mayo Clinic, Rochester, MN 55902 (United States); Mercier, George T. [Department of Physics, University of Houston, Houston, TX 77004 (United States); Barry, Michael A., E-mail: mab@mayo.edu [Department of Internal Medicine, Division of Infectious Diseases, Translational Immunovirology and Biodefense Program, Mayo Clinic, Rochester, MN 55902 (United States); Department of Immunology and Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55902 (United States)

    2015-08-15

    We developed adenovirus serotype 5 (Ad5) vectors displaying the sigma 1 protein from reovirus as mucosal vaccines. Ad5-sigma retargets to JAM-1 and sialic acid, but has 40-fold reduced gene delivery when compared to Ad5. While weaker at transduction, Ad5-sigma generates stronger T cell responses than Ad5 when used for mucosal immunization. In this work, new Ad5-fiber-sigma vectors were generated by varying the number of fiber β-spiral shaft repeats (R) between the fiber tail and sigma. Increasing chimera length led to decreasing insertion of these proteinsAd5 virions. Ad-R3 and R14 vectors effectively targeted JAM-1 in vitro while R20 did not. When wereused to immunize mice by the intranasal route, Ad5-R3-sigma produced higher serum and vaginal antibody responses than Ad5. These data suggest optimized Ad-sigma vectors may be useful vectors for mucosal vaccination. - Highlights: • Constructed adenoviruses (Ads) displaying different reovirus sigma 1 fusion proteins. • Progressively longer chimeras were more poorly encapsidated onto Ad virions. • Ad5-R3-sigma mediated better systemic and mucosal immune responses than Ad5.

  18. Establishment of Smad2 conditional gene targeting mice based on the Cre-LoxP system

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Jiang(周江); CHENG; Xuan(程萱); SUN; Yanxun(孙彦洵); HUANG; Peitang(黄培堂); HUANG; Cuifen(黄翠芬); YANG; Xiao(杨晓)

    2002-01-01

    Smads is a new gene family in transforming growth factor-β(TGF-β) signaling pathway. Smad2 mutated in multiple human tumors and may be a candidate tumor suppressor gene. Targeted disruption of murine Smad2 gene resulted in embryonic lethality at E6.5. To study the function of Smad2 in vertebrate organgenesis and tumorigenesis, we constructed the Smad2 conditional targeting vector in which two LoxP sequences were placed to flank the sequences encoding the C terminal functional domain of Smad2. The validity of the LoxP sites in the targeting construct was tested in E. coli that express the Cre recombinase constitutively. The vector was electroporated into ES cells and 3 targeted ES cell clones were obtained by Southern blot screening. Targeted ES cells were introduced into C57BL/6J blastocysts by microinjection to generate germ-line chimeras. Genotyping analysis showed that 2 progeny among these chimeras carried the Smad2 conditional targeted allele. The establishment of Smad2 conditional gene targeting mouse has laid a solid foundation for producing the tissue specific Smad2 gene knockout mice.

  19. T- and B-lymphocyte chimerism in the marmoset

    Energy Technology Data Exchange (ETDEWEB)

    Niblack, G.D.; Kateley, J.R.; Gengozian, N.

    1977-01-01

    Marmosets are natural blood chimeras, this condition resulting from the high frequency of fraternal twinning and the consistent development of placental vascular anastomoses between the two embryos. Identification of chimerism by sex-chromosome analysis of cultured blood lymphocytes provided a means of determining the proportion of chimerism among T and B lymphocytes. Peripheral blood lymphocytes were enriched for T or B cells by filtration through a nylon column (yields >95% T-cells) or inactivation of T lymphocytes by treatment with a goat anti-marmoset thymocyte antiserum in the presence of complement (yields >95% B cells). Mitogenic stimulation of these separated, enriched cell populations yielded metaphase plates which could be scored for percentage male and female cells. Tests on five different blood chimeras showed the T- and B-lymphocyte chimerism to be the same. Stimulation of blood lymphocytes with cells from another species of marmoset in a mixed lymphocyte culture test revealed the chimeric T-cell response (i.e., host and co-twin cells) to be similar to that obtained with a mitogenic lectin. The demonstration of equivalent T- and B-cell chimerism in these animals suggests derivation of these cells from a common stem cell pool and the response of both T-cell populations to an antigenic stimulus in proportions similar to their percentage chimerism suggests complete immunologic tolerance exists in this species for co-twin histocompatibility antigens.

  20. MMB-GUI: a fast morphing method demonstrates a possible ribosomal tRNA translocation trajectory.

    Science.gov (United States)

    Tek, Alex; Korostelev, Andrei A; Flores, Samuel Coulbourn

    2016-01-08

    Easy-to-use macromolecular viewers, such as UCSF Chimera, are a standard tool in structural biology. They allow rendering and performing geometric operations on large complexes, such as viruses and ribosomes. Dynamical simulation codes enable modeling of conformational changes, but may require considerable time and many CPUs. There is an unmet demand from structural and molecular biologists for software in the middle ground, which would allow visualization combined with quick and interactive modeling of conformational changes, even of large complexes. This motivates MMB-GUI. MMB uses an internal-coordinate, multiscale approach, yielding as much as a 2000-fold speedup over conventional simulation methods. We use Chimera as an interactive graphical interface to control MMB. We show how this can be used for morphing of macromolecules that can be heterogeneous in biopolymer type, sequence, and chain count, accurately recapitulating structural intermediates. We use MMB-GUI to create a possible trajectory of EF-G mediated gate-passing translocation in the ribosome, with all-atom structures. This shows that the GUI makes modeling of large macromolecules accessible to a wide audience. The morph highlights similarities in tRNA conformational changes as tRNA translocates from A to P and from P to E sites and suggests that tRNA flexibility is critical for translocation completion.

  1. Construction of a plasmid coding for green fluorescent protein tagged cathepsin L and data on expression in colorectal carcinoma cells

    Directory of Open Access Journals (Sweden)

    Tripti Tamhane

    2015-12-01

    Full Text Available The endo-lysosomal cysteine cathepsin L has recently been shown to have moonlighting activities in that its unexpected nuclear localization in colorectal carcinoma cells is involved in cell cycle progression (Tamhane et al., 2015 [1]. Here, we show data on the construction and sequence of a plasmid coding for human cathepsin L tagged with an enhanced green fluorescent protein (phCL-EGFP in which the fluorescent protein is covalently attached to the C-terminus of the protease. The plasmid was used for transfection of HCT116 colorectal carcinoma cells, while data from non-transfected and pEGFP-N1-transfected cells is also shown. Immunoblotting data of lysates from non-transfected controls and HCT116 cells transfected with pEGFP-N1 and phCL-EGFP, showed stable expression of cathepsin L-enhanced green fluorescent protein chimeras, while endogenous cathepsin L protein amounts exceed those of hCL-EGFP chimeras. An effect of phCL-EGFP expression on proliferation and metabolic states of HCT116 cells at 24 h post-transfection was observed.

  2. Faith-based perspectives on the use of chimeric organisms for medical research.

    Science.gov (United States)

    Degeling, Chris; Irvine, Rob; Kerridge, Ian

    2014-04-01

    Efforts to advance our understanding of neurodegenerative diseases involve the creation chimeric organisms from human neural stem cells and primate embryos--known as prenatal chimeras. The existence of potential mentally complex beings with human and non-human neural apparatus raises fundamental questions as to the ethical permissibility of chimeric research and the moral status of the creatures it creates. Even as bioethicists find fewer reasons to be troubled by most types of chimeric organisms, social attitudes towards the non-human world are often influenced by religious beliefs. In this paper scholars representing eight major religious traditions provide a brief commentary on a hypothetical case concerning the development and use of prenatal human-animal chimeric primates in medical research. These commentaries reflect the plurality and complexity within and between religious discourses of our relationships with other species. Views on the moral status and permissibility of research on neural human animal chimeras vary. The authors provide an introduction to those who seek a better understanding of how faith-based perspectives might enter into biomedical ethics and public discourse towards forms of biomedical research that involves chimeric organisms.

  3. Cell-Autonomous Repression of Shh by Transcription Factor Pax6 Regulates Diencephalic Patterning by Controlling the Central Diencephalic Organizer

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    Isabel Martín Caballero

    2014-09-01

    Full Text Available During development, region-specific patterns of regulatory gene expression are controlled by signaling centers that release morphogens providing positional information to surrounding cells. Regulation of signaling centers themselves is therefore critical. The size and the influence of a Shh-producing forebrain organizer, the zona limitans intrathalamica (ZLI, are limited by Pax6. By studying mouse chimeras, we find that Pax6 acts cell autonomously to block Shh expression in cells around the ZLI. Immunoprecipitation and luciferase assays indicate that Pax6 can bind the Shh promoter and repress its function. An analysis of chimeras suggests that many of the regional gene expression pattern defects that occur in Pax6−/− diencephalic cells result from a non-cell-autonomous position-dependent defect of local intercellular signaling. Blocking Shh signaling in Pax6−/− mutants reverses major diencephalic patterning defects. We conclude that Pax6’s cell-autonomous repression of Shh expression around the ZLI is critical for many aspects of normal diencephalic patterning.

  4. Cell-autonomous repression of Shh by transcription factor Pax6 regulates diencephalic patterning by controlling the central diencephalic organizer.

    Science.gov (United States)

    Caballero, Isabel Martín; Manuel, Martine N; Molinek, Michael; Quintana-Urzainqui, Idoia; Mi, Da; Shimogori, Tomomi; Price, David J

    2014-09-11

    During development, region-specific patterns of regulatory gene expression are controlled by signaling centers that release morphogens providing positional information to surrounding cells. Regulation of signaling centers themselves is therefore critical. The size and the influence of a Shh-producing forebrain organizer, the zona limitans intrathalamica (ZLI), are limited by Pax6. By studying mouse chimeras, we find that Pax6 acts cell autonomously to block Shh expression in cells around the ZLI. Immunoprecipitation and luciferase assays indicate that Pax6 can bind the Shh promoter and repress its function. An analysis of chimeras suggests that many of the regional gene expression pattern defects that occur in Pax6(-/-) diencephalic cells result from a non-cell-autonomous position-dependent defect of local intercellular signaling. Blocking Shh signaling in Pax6(-/-) mutants reverses major diencephalic patterning defects. We conclude that Pax6's cell-autonomous repression of Shh expression around the ZLI is critical for many aspects of normal diencephalic patterning.

  5. Could a zygote be a human being?

    Science.gov (United States)

    Burgess, John

    2010-02-01

    This paper re-examines the question of whether quirks of early human foetal development tell against the view (conceptionism) that we are human beings at conception. A zygote is capable of splitting to give rise to identical twins. Since the zygote cannot be identical with either human being it will become, it cannot already be a human being. Parallel concerns can be raised about chimeras in which two embryos fuse. I argue first that there are just two ways of dealing with cases of fission and fusion and both seem to be available to the conceptionist. One is the Replacement View according to which objects cease to exist when they fission or fuse. The other is the Multiple Occupancy View - both twins may be present already in the zygote and both persist in a chimera. So, is the conceptionist position tenable after all? I argue that it is not. A zygote gives rise not only to a human being but also to a placenta - it cannot already be both a human being and a placenta. Neither approach to fission and fusion can help the conceptionist with this problem. But worse is in store. Both fission and fusion can occur before and after the development of the inner cell mass of the blastocyst - the entity which becomes the embryo proper. The idea that we become human beings with the arrival of the inner cell mass leads to bizarre results however we choose to accommodate fission and fusion.

  6. Reconstruction of ribosomal RNA genes from metagenomic data.

    Directory of Open Access Journals (Sweden)

    Lu Fan

    Full Text Available Direct sequencing of environmental DNA (metagenomics has a great potential for describing the 16S rRNA gene diversity of microbial communities. However current approaches using this 16S rRNA gene information to describe community diversity suffer from low taxonomic resolution or chimera problems. Here we describe a new strategy that involves stringent assembly and data filtering to reconstruct full-length 16S rRNA genes from metagenomicpyrosequencing data. Simulations showed that reconstructed 16S rRNA genes provided a true picture of the community diversity, had minimal rates of chimera formation and gave taxonomic resolution down to genus level. The strategy was furthermore compared to PCR-based methods to determine the microbial diversity in two marine sponges. This showed that about 30% of the abundant phylotypes reconstructed from metagenomic data failed to be amplified by PCR. Our approach is readily applicable to existing metagenomic datasets and is expected to lead to the discovery of new microbial phylotypes.

  7. EFFECTS OF INTEGRIN ALPHA ⅡbR995A MUTATION ON RECEPTOR AFFINITY AND pp 125 (FAK) PHOSPHORYLATION

    Institute of Scientific and Technical Information of China (English)

    Xue-yuan Tang; Zai-fu Jian; Guo-ping Wang; Hong-hui Yang; Wei Liu

    2004-01-01

    Objective To investigate the role of cytoplasmic domain of integrin alpha Ⅱb in platelet signal transduction.Methods Binding capacity of integrin alpha ⅡbR995Ato antibody platelet activation complex-1 (PAC-1) and pp125focal adhesion kinase (FAK) phosphorylation of cells were detected by flow cytometry, immune precipitation, and Western blotting.Results Without activation, wild-type alpha Ⅱ bbeta3 Chinese hamster ovary (CHO) cells failed to bind to PAC-1, but mutant chimera alpha ⅡbR995Aeta3 CHO cells were able to bind with PAC-1. Furthermore, phosphorylation of pp125 (FAK)in wild-type alpha Ⅱbbeta3 CHO cells occured only when cells were adhered to fibrinogen, but could not be detected in bovine serum albumin suspension. However in the mutant chimera group, it could be detected in both conditions.Conclusion The mutation in integrin alpha ⅡbR995Aalters its affinity state as a receptor, thus also mediating cytoplasmic signal transduction leading to the phosphorylation of pp125 (FAK) without ligand binding.

  8. Bone marrow-derived HL mitigates bone marrow-derived CETP-mediated decreases in HDL in mice globally deficient in HL and the LDLr.

    Science.gov (United States)

    Hime, Neil J; Black, Audrey S; Bonnet, David J; Curtiss, Linda K

    2014-09-01

    The objective of this study was to determine the combined effects of HL and cholesteryl ester transfer protein (CETP), derived exclusively from bone marrow (BM), on plasma lipids and atherosclerosis in high-fat-fed, atherosclerosis-prone mice. We transferred BM expressing these proteins into male and female double-knockout HL-deficient, LDL receptor-deficient mice (HL(-/-)LDLr(-/-)). Four BM chimeras were generated, where BM-derived cells expressed 1) HL but not CETP, 2) CETP and HL, 3) CETP but not HL, or 4) neither CETP nor HL. After high-fat feeding, plasma HDL-cholesterol (HDL-C) was decreased in mice with BM expressing CETP but not HL (17 ± 4 and 19 ± 3 mg/dl, female and male mice, respectively) compared with mice with BM expressing neither CETP nor HL (87 ± 3 and 95 ± 4 mg/dl, female and male mice, respectively, P HL mitigated this CETP-mediated decrease in HDL-C. BM-derived CETP decreased the cholesterol component of HDL particles and increased plasma cholesterol. BM-derived HL mitigated these effects of CETP. Atherosclerosis was not significantly different between BM chimeras. These results suggest that BM-derived HL mitigates the HDL-lowering, HDL-modulating, and cholesterol-raising effects of BM-derived CETP and warrant further studies to characterize the functional properties of these protein interactions.

  9. Intracellular itinerary of internalised β-secretase, BACE1, and its potential impact on β-amyloid peptide biogenesis.

    Science.gov (United States)

    Chia, Pei Zhi Cheryl; Toh, Wei Hong; Sharples, Robyn; Gasnereau, Isabelle; Hill, Andrew F; Gleeson, Paul A

    2013-09-01

    β-Secretase (BACE1) cleavage of the amyloid precursor protein (APP) represents the initial step in the formation of the Alzheimer's disease associated amyloidogenic Aβ peptide. Substantive evidence indicates that APP processing by BACE1 is dependent on intracellular sorting of this enzyme. Nonetheless, knowledge of the intracellular trafficking pathway of internalised BACE1 remains in doubt. Here we show that cell surface BACE1 is rapidly internalised by the AP2/clathrin dependent pathway in transfected cells and traffics to early endosomes and Rab11-positive, juxtanuclear recycling endosomes, with very little transported to the TGN as has been previously suggested. Moreover, BACE1 is predominantly localised to the early and recycling endosome compartments in different cell types, including neuronal cells. In contrast, the majority of internalised wild-type APP traffics to late endosomes/lysosomes. To explore the relevance of the itinerary of BACE1 on APP processing, we generated a BACE1 chimera containing the cytoplasmic tail of TGN38 (BACE/TGN38), which cycles between the cell surface and TGN in an AP2-dependent manner. Wild-type BACE1 is less efficient in Aβ production than the BACE/TGN38 chimera, highlighting the relevance of the itinerary of BACE1 on APP processing. Overall the data suggests that internalised BACE1 and APP diverge at early endosomes and that Aβ biogenesis is regulated in part by the recycling itinerary of BACE1.

  10. The potential for archiving and reconstituting valuable strains of turkey (Meleagris gallopavo) using primordial germ cells.

    Science.gov (United States)

    Wade, Alexander J; French, Nick A; Ireland, Grenham W

    2014-04-01

    Diseases such as avian influenza can destroy turkey flocks, potentially resulting in the loss of valuable or rare genetic material. Consequently, there is an urgent need to develop a means to archive such germplasm. Germline chimeras produced by intravascular transfer of primordial germ cells (PGC) have been reported in other avian species but not turkeys. This study examined the feasibility of both establishing an archive of frozen PGC, and producing germline chimeras by injecting the thawed PGC into host embryos. To meet these aims, the following experiments were performed: (1) PGC identification within turkey embryos; (2) development of an efficient method for isolation of turkey PGC; (3) demonstration that PGC can be cryopreserved, recovered, and retain viability; (4) reinjection into embryos and detection of injected PGC. Primordial germ cells were identified using periodic acid-Schiff reagent and the immunological marker OLP-1. Bloodstream PGC were isolated using Ficoll density gradient centrifugation with PGC recovery peaking at stages 13, 14, and 15 with 32 ± 4.9, 33 ± 6.4, and 26 ± 5.4 PGC recovered, respectively. Primordial germ cells were frozen using Dulbecco's modified Eagle medium, 20% fetal calf serum, and 10% dimethylsulfoxide and demonstrated 90 ± 1.7% viability after 3 mo frozen in liquid nitrogen. Freshly isolated and frozen thawed DiI- and Q-Tracker-labeled PGC repopulated stage 30 gonads after vascular transfer into ex ovo cultured embryos. The DiI-labeled cells repopulated gonads less frequently, with 36 ± 13.2% of gonads containing the DiI-labeled PGC, and 7 ± 3.8% of reinjected PGC reaching the gonads of positive embryos. The Q-tracker-labeled cells were detected more frequently in embryos, with 67 ± 21.1% having positive signals, and 44 ± 4.9% of reinjected Q-tracker-labeled PGC colonized the gonads of positive embryos. This study demonstrated the feasibility of using turkey PGC to archive turkey germplasm from different strains

  11. Distinct regions of Galpha13 participate in its regulatory interactions with RGS homology domain-containing RhoGEFs.

    Science.gov (United States)

    Kreutz, Barry; Hajicek, Nicole; Yau, Douglas M; Nakamura, Susumu; Kozasa, Tohru

    2007-08-01

    Galpha12 and Galpha13 transduce signals from G protein-coupled receptors to RhoA through RhoGEFs containing an RGS homology (RH) domain, such as p115 RhoGEF or leukemia-associated RhoGEF (LARG). The RH domain of p115 RhoGEF or LARG binds with high affinity to active forms of Galpha12 and Galpha13 and confers specific GTPase-activating protein (GAP) activity, with faster GAP responses detected in Galpha13 than in Galpha12. At the same time, Galpha13, but not Galpha12, directly stimulates the RhoGEF activity of p115 RhoGEF or nonphosphorylated LARG in reconstitution assays. In order to better understand the molecular mechanism by which Galpha13 regulates RhoGEF activity through interaction with RH-RhoGEFs, we sought to identify the region(s) of Galpha13 involved in either the GAP response or RhoGEF activation. For this purpose, we generated chimeras between Galpha12 and Galpha13 subunits and characterized their biochemical activities. In both cell-based and reconstitution assays of RhoA activation, we found that replacing the carboxyl-terminal region of Galpha12 (residues 267-379) with that of Galpha13 (residues 264-377) conferred gain-of-function to the resulting chimeric subunit, Galpha12C13. The inverse chimera, Galpha13C12, exhibited basal RhoA activation which was similar to Galpha12. In contrast to GEF assays, GAP assays showed that Galpha12C13 or Galpha13C12 chimeras responded to the GAP activity of p115 RhoGEF or LARG in a manner similar to Galpha12 or Galpha13, respectively. We conclude from these results that the carboxyl-terminal region of Galpha13 (residues 264-377) is essential for its RhoGEF stimulating activity, whereas the amino-terminal alpha helical and switch regions of Galpha12 and Galpha13 are responsible for their differential GAP responses to the RH domain.

  12. Mac-2 binding protein is a novel E-selectin ligand expressed by breast cancer cells.

    Science.gov (United States)

    Shirure, Venktesh S; Reynolds, Nathan M; Burdick, Monica M

    2012-01-01

    Hematogenous metastasis involves the adhesion of circulating tumor cells to vascular endothelium of the secondary site. We hypothesized that breast cancer cell adhesion is mediated by interaction of endothelial E-selectin with its glycoprotein counter-receptor(s) expressed on breast cancer cells. At a hematogenous wall shear rate, ZR-75-1 breast cancer cells specifically adhered to E-selectin expressing human umbilical vein endothelial cells when tested in parallel plate flow chamber adhesion assays. Consistent with their E-selectin ligand activity, ZR-75-1 cells expressed flow cytometrically detectable epitopes of HECA-452 mAb, which recognizes high efficiency E-selectin ligands typified by sialofucosylated moieties. Multiple E-selectin reactive proteins expressed by ZR-75-1 cells were revealed by immunoprecipitation with E-selectin chimera (E-Ig chimera) followed by Western blotting. Mass spectrometry analysis of the 72 kDa protein, which exhibited the most prominent E-selectin ligand activity, corresponded to Mac-2 binding protein (Mac-2BP), a heretofore unidentified E-selectin ligand. Immunoprecipitated Mac-2BP expressed sialofucosylated epitopes and possessed E-selectin ligand activity when tested by Western blot analysis using HECA-452 mAb and E-Ig chimera, respectively, demonstrating that Mac-2BP is a novel high efficiency E-selectin ligand. Furthermore, silencing the expression of Mac-2BP from ZR-75-1 cells by shRNA markedly reduced their adhesion to E-selectin expressing cells under physiological flow conditions, confirming the functional E-selectin ligand activity of Mac-2BP on intact cells. In addition to ZR-75-1 cells, several other E-selectin ligand positive breast cancer cell lines expressed Mac-2BP as detected by Western blot and flow cytometry, suggesting that Mac-2BP may be an E-selectin ligand in a variety of breast cancer types. Further, invasive breast carcinoma tissue showed co-localized expression of Mac-2BP and HECA-452 antigens by

  13. Mouse amnionless, which is required for primitive streak assembly, mediates cell-surface localization and endocytic function of cubilin on visceral endoderm and kidney proximal tubules.

    Science.gov (United States)

    Strope, Sharon; Rivi, Roberta; Metzger, Thomas; Manova, Katia; Lacy, Elizabeth

    2004-10-01

    Impaired primitive streak assembly in the mouse amnionless (amn) mutant results in the absence of non-axial trunk mesoderm, a derivative of the middle region of the primitive streak. In addition, the epiblast of amn mutants fails to increase significantly in size after E7.0, indicating that middle primitive streak assembly is mechanistically tied to the growth of the embryo during gastrulation. Amn, a novel transmembrane protein, is expressed exclusively in an extra-embryonic tissue, visceral endoderm (VE), during the early post-implantation stages. We show that Amn is also expressed in kidney proximal tubules (KPT) and intestinal epithelium, which, like the VE, are polarized epithelia specialized for resorption and secretion. To explore whether Amn participates in the development or function of KPT and intestinal epithelia and to gain insight into the function of Amn during gastrulation, we constructed Amn(-/-) ES cell+/+ blastocyst chimeras. While chimeras form anatomically normal kidneys and intestine, they exhibit variable, selective proteinuria, a sign of KPT malfunction. In humans, AMN has been genetically connected to Cubilin (CUBN), a multi-ligand scavenger receptor expressed by KPT, intestine and yolk sac. Loss of CUBN, the intestinal intrinsic factor (IF)-vitamin B12 receptor, results in hereditary megaloblastic anemia (MGA1), owing to vitamin B12 malabsorption. The recent report of MGA1 families with mutations in AMN suggests that AMN functions in the same pathway as CUBN. We demonstrate that Cubn is not properly localized to the cell surface in Amn(-/-) tissues in the embryo and adult mouse, and that adult chimeras exhibit selective proteinuria of Cubn ligands. This study demonstrates that Amn is an essential component of the Cubn receptor complex in vivo and suggests that Amn/Cubn is required for endocytosis/transcytosis of one or more ligands in the VE during gastrulation to coordinate growth and patterning of the embryo. Furthermore, as AMN is

  14. Coral kin aggregations exhibit mixed allogeneic reactions and enhanced fitness during early ontogeny

    Directory of Open Access Journals (Sweden)

    Chadwick Nanette E

    2008-04-01

    Full Text Available Abstract Background Aggregated settlement of kin larvae in sessile marine invertebrates may result in a complex array of compatible and incompatible allogeneic responses within each assemblage. Each such aggregate can, therefore, be considered as a distinct self-organizing biological entity representing adaptations that have evolved to maximize the potential benefits of gregarious settlement. However, only sparse information exists on the selective forces and ecological consequences of allogeneic coalescence. Results We studied the consequences of aggregated settlement of kin larvae of Stylophora pistillata (a Red Sea stony coral, under controlled laboratory settings. When spat came into contact, they either fused, establishing a chimera, or rejected one another. A one-year study on growth and survivorship of 544 settled S. pistillata genotypes revealed six types of biological entities: (1 Single genotypes (SG; (2 Bi-chimeras (BC; (3 Bi-rejecting genotypes (BR; (4 Tri-chimera entities (TC; (5 Three-rejecting genotypes (TR; and (6 Multi-partner entities (MP; consisting of 7.5 ± 2.6 partners. Analysis of allorecognition responses revealed an array of effector mechanisms: real tissue fusions, transitory fusions and six other histoincompatible reactions (borderline formation, sutures, overgrowth, bleaching, rejection, and partner death, disclosing unalike onsets of ontogeny and complex modes of appearance within each aggregate. Evaluations at the entity level revealed that MP entities were the largest, especially in the first two months (compared with SG: 571% in the first month and 162% in the seventh month. However, at the genotype level, the SG entities were the largest and the colonies with the highest-cost-per-genotype were the TR and the MP colonies. The cost was calculated as reduced average genotype size, from 27% and 12% in the first month to 67% and 64% in the seventh month, respectively. In general, MP exhibited the highest survivorship

  15. Generation of human/rat xenograft animal model for the study of human donor stem cell behaviors in vivo

    Institute of Scientific and Technical Information of China (English)

    Yan Sun; Dong Xiao; Xing-Hua Pan; Ruo-Shuang Zhang; Guang-Hui Cui; Xi-Gu Chen

    2007-01-01

    AIM: To accurately and realistically elucidate human stem cell behaviors In vivo and the fundamental mechanisms controlling human stem cell fates in vivo, which is urgently required in regenerative medicine and treatments for some human diseases, a surrogate human-rat chimera model was developed.METHODS: Human-rat chimeras were achieved by in utero transplanting low-density mononuclear cells from human umbilical cord blood into the fetal rats at 9-11 d of gestation, and subsequently, a variety of methods, including flow cytometry, PCR as well as immunohistochemical assay, were used to test the human donor contribution in the recipients.RESULTS: Of 29 live-born recipients, 19 had the presence of human CD45+ cells in peripheral blood (PB) detected by flow cytometry, while PCR analysis on genomic DNA from 11 different adult tissues showed that 14 selected from flow cytometry-positive 19 animals possessed of donor-derived human cell engraftment in multiple tissues (i.e. liver, spleen, thymus, heart, kidney, blood, lung, muscle, gut and skin) examined at the time of tissue collection, as confirmed by detecting human β2-microglobulin expression using immunohistochemistry.In this xenogeneic system, the engrafted donor-derived human cells persisted in multiple tissues for at least 6 mo after birth. Moreover, transplanted human donor cells underwent site-specific differentiation into CK18-positive human cells in chimeric liver and CD45-positive human cells in chimeric spleen and thymus of recipients.CONCLUSION: Taken together, these findings suggest that we successfully developed human-rat chimeras, in which xenogeneic human cells exist up to 6 mo later. This humanized small animal model, which offers an in vivo environment more closely resembling to the situations in human, provides an invaluable and effective approach for in vivo investigating human stem cell behaviors, and further in vivo examining fundamental mechanisms controlling human stem cell fates in the future

  16. The Eag domain regulates the voltage-dependent inactivation of rat Eag1 K+ channels.

    Directory of Open Access Journals (Sweden)

    Ting-Feng Lin

    Full Text Available Eag (Kv10 and Erg (Kv11 belong to two distinct subfamilies of the ether-à-go-go K+ channel family (KCNH. While Erg channels are characterized by an inward-rectifying current-voltage relationship that results from a C-type inactivation, mammalian Eag channels display little or no voltage-dependent inactivation. Although the amino (N-terminal region such as the eag domain is not required for the C-type inactivation of Erg channels, an N-terminal deletion in mouse Eag1 has been shown to produce a voltage-dependent inactivation. To further discern the role of the eag domain in the inactivation of Eag1 channels, we generated N-terminal chimeras between rat Eag (rEag1 and human Erg (hERG1 channels that involved swapping the eag domain alone or the complete cytoplasmic N-terminal region. Functional analyses indicated that introduction of the homologous hERG1 eag domain led to both a fast phase and a slow phase of channel inactivation in the rEag1 chimeras. By contrast, the inactivation features were retained in the reverse hERG1 chimeras. Furthermore, an eag domain-lacking rEag1 deletion mutant also showed the fast phase of inactivation that was notably attenuated upon co-expression with the rEag1 eag domain fragment, but not with the hERG1 eag domain fragment. Additionally, we have identified a point mutation in the S4-S5 linker region of rEag1 that resulted in a similar inactivation phenotype. Biophysical analyses of these mutant constructs suggested that the inactivation gating of rEag1 was distinctly different from that of hERG1. Overall, our findings are consistent with the notion that the eag domain plays a critical role in regulating the inactivation gating of rEag1. We propose that the eag domain may destabilize or mask an inherent voltage-dependent inactivation of rEag1 K+ channels.

  17. In vitro and in vivo study of pluripotency in intraspecific hybrid cells obtained by fusion of murine embryonic stem cells with splenocytes.

    Science.gov (United States)

    Matveeva, N M; Shilov, A G; Kaftanovskaya, E M; Maximovsky, L P; Zhelezova, A I; Golubitsa, A N; Bayborodin, S I; Fokina, M M; Serov, O L

    1998-06-01

    Hypoxanthine phosphoribosyltransferase-deficient (HPRT-) mouse embryonic stem (ES) cells, HM-1 cells (genotype XY), were fused with adult female DD/c mouse spleen cells. As a result, a set of HAT-resistant clones was isolated. Four hybrid clones most similar in morphology and growth characteristics to the HM-1 cells were studied in detail with respect to their pluripotency. Of these, three clones contained 41-43 chromosomes, and one clone was nearly tetraploid. All the clones had the XXY set of sex chromosomes and expressed the HPRT of the somatic partner only. The hybrid clones shared features with the HM-1 cells, indicating that they retained their pluripotent properties: (1) embryonic ECMA-7 antigen, not TROMA-1 antigen, was present in most cells; (2) the hybrid cells showed high activity of endogenous alkaline phosphatase (AP); (3) all the hybrid clones were able to form complex embryoid bodies containing derivatives of all the embryonic germinal layers; (4) the hybrid cells contained synchronously replicating X chromosomes, indicating that they were in an active state; and (5) a set of chimeric animals was generated by injecting hybrid cells into BALB/c and C57BL/6J mouse blastocysts. Evidence for chimerism was provided by the spotted coat derived from 129/Ola mice and identification of 129/Ola glucose phosphate isomerase (GPI) in many organs. Thus the results obtained demonstrated that the hybrid cells retain their high pluripotency level despite the close contact of the "pluripotent" HM-1 genome with the "somatic" spleen cell genome during hybrid cell formation and the presence of the "somatic" X chromosome during many cell generations. The presence of HPRT of the somatic partner in many organs and tissues, including the testes in chimeric animals, shows that the "somatic" X chromosome segregates weakly, if at all, during development of the chimeras. There were no individuals with the 129/Ola genotype among the more than 50 offspring from chimeric mice. The

  18. VSEARCH: a versatile open source tool for metagenomics

    Science.gov (United States)

    Flouri, Tomáš; Nichols, Ben; Quince, Christopher; Mahé, Frédéric

    2016-01-01

    Background VSEARCH is an open source and free of charge multithreaded 64-bit tool for processing and preparing metagenomics, genomics and population genomics nucleotide sequence data. It is designed as an alternative to the widely used USEARCH tool (Edgar, 2010) for which the source code is not publicly available, algorithm details are only rudimentarily described, and only a memory-confined 32-bit version is freely available for academic use. Methods When searching nucleotide sequences, VSEARCH uses a fast heuristic based on words shared by the query and target sequences in order to quickly identify similar sequences, a similar strategy is probably used in USEARCH. VSEARCH then performs optimal global sequence alignment of the query against potential target sequences, using full dynamic programming instead of the seed-and-extend heuristic used by USEARCH. Pairwise alignments are computed in parallel using vectorisation and multiple threads. Results VSEARCH includes most commands for analysing nucleotide sequences available in USEARCH version 7 and several of those available in USEARCH version 8, including searching (exact or based on global alignment), clustering by similarity (using length pre-sorting, abundance pre-sorting or a user-defined order), chimera detection (reference-based or de novo), dereplication (full length or prefix), pairwise alignment, reverse complementation, sorting, and subsampling. VSEARCH also includes commands for FASTQ file processing, i.e., format detection, filtering, read quality statistics, and merging of paired reads. Furthermore, VSEARCH extends functionality with several new commands and improvements, including shuffling, rereplication, masking of low-complexity sequences with the well-known DUST algorithm, a choice among different similarity definitions, and FASTQ file format conversion. VSEARCH is here shown to be more accurate than USEARCH when performing searching, clustering, chimera detection and subsampling, while on a par

  19. Crystallization of the Zalpha domain of the human editing enzyme ADAR1 complexed with a DNA-RNA chimeric oligonucleotide in the left-handed Z-conformation.

    Science.gov (United States)

    Brown, Bernard A; Athanasiadis, Alekos; Hanlon, Eugene B; Lowenhaupt, Ky; Wilbert, Christina M; Rich, Alexander

    2002-01-01

    The Zalpha domain of human double-stranded RNA adenosine deaminase (ADAR1) has been crystallized with a hexanucleotide containing alternating deoxyribose and ribose furanose sugars. Solution circular dichroism experiments show that this double-stranded chimera (dCrG)(3) initially adopts the right-handed A-conformation. However, addition of stoichiometric amounts of Zalpha causes a rapid transition to the Z-conformation. Raman spectroscopy of crystals of the Zalpha-(dCrG)(3) complex confirm that the chimeric oligonucleotide is stabilized in the Z-conformation. A complete data set has been obtained at 2.5 A resolution. The Zalpha-(dCrG)(3) crystals belong to the tetragonal I422 space group, with unit-cell parameters a = b = 104.2, c = 117.6 A. Work is under way to solve the structure by molecular replacement.

  20. Melon (Cucumis melo).

    Science.gov (United States)

    Nonaka, Satoko; Ezura, Hiroshi

    2015-01-01

    Genetic transformation is an important technique used in plant breeding and to functionally characterize genes of interest. The earliest reports of Agrobacterium-mediated transformation in the melon (Cucumis melo) were from the early 1990s (Fang and Grumet, Plant Cell Rep, 9: 160-164, 1990; Dong et al., Nat Biotechnol 9: 858-863, 1991; Valles and Lasa, Plant Cell Rep 13: 145-148, 1994). These early studies described three problems that decreased the efficiency of transformation: tetraploidy, chimeras, and escape. Using a liquid culture system for somatic embryogenesis, Akasaka-Kenedy et al. (Plant Sci 166: 763-769, 2004) overcame these problems and established an efficient transformation system; the protocol introduced in this chapter is based on this method.