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Sample records for boundaries regulates formation

  1. Line tension at lipid phase boundaries regulates formation of membrane vesicles in living cells

    DEFF Research Database (Denmark)

    Vind-Kezunovic, D.; Nielsen, C.H.; Wojewodzka, U.;

    2008-01-01

    Ternary lipid compositions in model membranes segregate into large-scale liquid-ordered (L(o)) and liquid-disordered (L(d)) phases. Here, we show mum-sized lipid domain separation leading to vesicle formation in unperturbed human HaCaT keratinocytes. Budding vesicles in the apical portion of the....... Based on these observations we describe the energetic requirements for plasma membrane vesiculation. We propose that the decrease in total 'L(o)/L(d)' boundary line tension arising from the coalescence of smaller L(d)-like domains makes it energetically favourable for L(d)-like domains to bend from flat...

  2. HISTONE METHYLATION REGULATES MEMORY FORMATION

    OpenAIRE

    Gupta, Swati; Kim, Se Y.; Artis, Sonja; Molfese, David L.; Schumacher, Armin; Sweatt, J. David; Paylor, Richard E.; Lubin, Farah D.

    2010-01-01

    It has been established that regulation of chromatin structure through post-translational modification of histone proteins, primarily histone H3 phosphorylation and acetylation, is an important early step in the induction of synaptic plasticity and formation of long-term memory. In this study, we investigated the contribution of another histone modification, histone methylation, to memory formation in the adult hippocampus. We found that tri-methylation of histone H3 at lysine 4 (H3K4), an ac...

  3. ON A PARABOLIC FREE BOUNDARY EQUATION MODELING PRICE FORMATION

    KAUST Repository

    MARKOWICH, P. A.

    2009-10-01

    We discuss existence and uniqueness of solutions for a one-dimensional parabolic evolution equation with a free boundary. This problem was introduced by Lasry and Lions as description of the dynamical formation of the price of a trading good. Short time existence and uniqueness is established by a contraction argument. Then we discuss the issue of global-in-time-extension of the local solution which is closely related to the regularity of the free boundary. We also present numerical results. © 2009 World Scientific Publishing Company.

  4. How Galactic Environment Regulates Star Formation

    Science.gov (United States)

    Meidt, Sharon E.

    2016-02-01

    In a new simple model I reconcile two contradictory views on the factors that determine the rate at which molecular clouds form stars—internal structure versus external, environmental influences—providing a unified picture for the regulation of star formation in galaxies. In the presence of external pressure, the pressure gradient set up within a self-gravitating turbulent (isothermal) cloud leads to a non-uniform density distribution. Thus the local environment of a cloud influences its internal structure. In the simple equilibrium model, the fraction of gas at high density in the cloud interior is determined simply by the cloud surface density, which is itself inherited from the pressure in the immediate surroundings. This idea is tested using measurements of the properties of local clouds, which are found to show remarkable agreement with the simple equilibrium model. The model also naturally predicts the star formation relation observed on cloud scales and at the same time provides a mapping between this relation and the closer-to-linear molecular star formation relation measured on larger scales in galaxies. The key is that pressure regulates not only the molecular content of the ISM but also the cloud surface density. I provide a straightforward prescription for the pressure regulation of star formation that can be directly implemented in numerical models. Predictions for the dense gas fraction and star formation efficiency measured on large-scales within galaxies are also presented, establishing the basis for a new picture of star formation regulated by galactic environment.

  5. Slow solar wind boundaries and implication for its formation

    Science.gov (United States)

    Ko, Yuan-Kuen; Roberts, Aaron; Lepri, Susan; Kocher, Manan

    2015-04-01

    Solar wind and the associated magnetic field permeate the heliosphere. Their temporal and spatial variations contribute significantly in the large range of variations in related geomagnetic effects as well as in the properties of solar energetic particles. Among the least understood is the slow solar wind for how it is formed at the Sun and what causes the large variations in its physical properties. This work investigates the variations in the slow solar wind streams measured in-situ at 1 AU and the correlations among the protons, heavy ions, suprathermal electrons, and magnetic field properties. Besides well-established correlations among the proton speed, proton temperature and ion charge states, we also found certain distinct characteristics in the correlation and temporal relationship between the ion charge states, proton velocity fluctuations and, in many cases, suprathermal electron halos. The implications from our findings in the slow wind formation and whether the slow wind has a distinct boundary with the fast wind will be discussed.

  6. Formation of the wave compressional boundary in the earth's foreshock

    Science.gov (United States)

    Skadron, George; Holdaway, Robert D.; Lee, Martin A.

    1988-01-01

    Using an evolutionary model and allowing for nonuniform proton injection and wave growth rates, the compressional wave boundaries corresponding to IMF inclinations to the solar wind of theta(BV) equal to 45 and 25 deg were located. The compressional boundaries deduced from this model were found to support the results of Greenstadt and Baum (1986) who have concluded that the observed compressional boundaries are incompatible with wave growth at a fixed growth rate, due to the interaction of a uniform beam with the solar wind. The results indicate, however, that the compressional boundaries are quite compatible with nonuniform beams and growth rates which result from the coupled evolution of the energetic protons and the waves with which they interact. It was found that, in the solar wind frame, the dominant wave-particle interaction in the outer foreshock is the damping of inward propagating (toward the shock) left-polarized waves, producing a magnetically quiet region immediately downstream of the foreshock boundary.

  7. How galactic environment regulates star formation

    CERN Document Server

    Meidt, Sharon E

    2015-01-01

    In a new simple model I reconcile two contradictory views on the factors that determine the rate at which molecular clouds form stars -- internal structure vs. external, environmental influences -- providing a unified picture for the regulation of star formation in galaxies. In the presence of external pressure, the pressure gradient set up within a self-gravitating isothermal cloud leads to a non-uniform density distribution. Thus the local environment of a cloud influences its internal structure. In the simple equilibrium model, the fraction of gas at high density in the cloud interior is determined simply by the cloud surface density, which is itself inherited from the pressure in the immediate surroundings. This idea is tested using measurements of the properties of local clouds, which are found to show remarkable agreement with the simple equilibrium model. The model also naturally predicts the star formation relation observed on cloud scales and, at the same time, provides a mapping between this relatio...

  8. A distinct magnetic property of the inner penumbral boundary. Formation of a stable umbra-penumbra boundary in a sunspot

    Science.gov (United States)

    Jurčák, J.; Bello González, N.; Schlichenmaier, R.; Rezaei, R.

    2015-08-01

    Context. A sunspot emanates from a growing pore or protospot. In order to trigger the formation of a penumbra, large inclinations at the outskirts of the protospot are necessary. The penumbra develops and establishes by colonising both umbral areas and granulation. Evidence for a unique stable boundary value for the vertical component of the magnetic field strength, Bstablever, was found along the umbra-penumbra boundary of developed sunspots. Aims: We study the changing value of Bver as the penumbra forms and as it reaches a stable state. We compare this with the corresponding value in fully developed penumbrae. Methods: We use broadband G-band images and spectropolarimetric GFPI/VTT data to study the evolution of and the vertical component of the magnetic field on a forming umbra-penumbra boundary. For comparison with stable sunspots, we also analyse the two maps observed by Hinode/SP on the same spot after the penumbra formed. Results: The vertical component of the magnetic field, Bver, at the umbra-penumbra boundary increases during penumbra formation owing to the incursion of the penumbra into umbral areas. After 2.5 h, the penumbra reaches a stable state as shown by the GFPI data. At this stable stage, the simultaneous Hinode/SP observations show a Bver value comparable to that of umbra-penumbra boundaries of fully fledged sunspots. Conclusions: We confirm that the umbra-penumbra boundary, traditionally defined by an intensity threshold, is also characterised by a distinct canonical magnetic property, namely by Bverstable. During the penumbra formation process, the inner penumbra extends into regions where the umbra previously prevailed. Hence, in areas where Bverboundary settles at Bverstable, which hints toward the role of Bverstable as inhibitor of the penumbral mode of magneto-convection.

  9. WOX2 and STIMPY-LIKE/WOX8 promote cotyledon boundary formation in Arabidopsis.

    Science.gov (United States)

    Lie, Catharine; Kelsom, Corey; Wu, Xuelin

    2012-11-01

    One of the key events in dicot plant embryogenesis is the emergence of the two cotyledon primordia, which marks the transition from radial symmetry to bilateral symmetry. In Arabidopsis thaliana, the three CUP-SHAPED COTYLEDON (CUC) genes are responsible for determining the boundary region between the cotyledons. However, the mechanisms controlling their transcription activation are not well understood. Previous studies found that several WOX family homeobox transcription factors are involved in embryo apical patterning and cotyledon development. Here we show that WOX2 and STIMPY-LIKE (STPL/WOX8) act redundantly to differentially regulate the expression of the CUC genes in promoting the establishment of the cotyledon boundary, without affecting the primary shoot meristem. Loss of both WOX2 and STPL results in reduced CUC2 and CUC3 expression in one side of the embryo, but an expansion of the CUC1 domain. Furthermore, we found that STPL is expressed in the embryo proper, and its activation is enhanced by the removal of WOX2, providing an explanation for the functional redundancy between WOX2 and STPL. Additional evidence also showed that WOX2 and STPL function independently in regulating different aspects of local auxin gradient formation during early embryogenesis. PMID:22827849

  10. Interaction of shear-coupled grain boundary motion with crack: Crack healing, grain boundary decohesion, and sub-grain formation

    Science.gov (United States)

    Aramfard, Mohammad; Deng, Chuang

    2016-02-01

    Stress-driven grain boundary motion is one of the main mechanisms responsible for microstructural evolution in polycrystalline metals during deformation. In this research, the interaction of shear-coupled grain boundary motion (SCGBM) in face-centered cubic metals with crack, which is a common type of structural defects in engineering materials, has been studied by using molecular dynamics simulations in simple bicrystal models. The influences of different parameters such as metal type, temperature, grain boundary structure, and crack geometry have been examined systematically. Three types of microstructural evolution have been identified under different circumstances, namely, crack healing, grain boundary decohesion, and sub-grain formation. The underlying atomistic mechanisms for each type of SCGBM-crack interaction, particularly grain boundary decohesion and crack healing, have also been examined. It is found that crack healing is generally favoured during the SCGBM-crack interaction at relatively high temperature in metals with relatively low stacking fault energy and grain boundary structure with relatively low misorientation angles. The results of this work may open up new opportunities for healing severely damaged materials.

  11. Lbx2 regulates formation of myofibrils

    Directory of Open Access Journals (Sweden)

    Westerfield Monte

    2009-02-01

    Full Text Available Abstract Background Skeletal muscle differentiation requires assembly of contractile proteins into organized myofibrils. The Drosophila ladybird homeobox gene (lad functions in founder cells of the segmental border muscle to promote myoblast fusion and muscle shaping. Tetrapods have two homologous genes (Lbx. Lbx1 functions in migration and/or proliferation of hypaxial myoblasts, whereas the function of Lbx2 is poorly understood. Results To elucidate the role of Lbx in vertebrate myogenesis, we examined Lbx function in zebrafish. Zebrafish lbx2 transcripts appear in newly formed paraxial mesoderm and become restricted to adaxial cells, precursors of slow muscle. Slow muscles lose lbx2 expression as they differentiate, while a subset of differentiating fast muscle cells transiently expresses lbx2. Fin and hyoid muscle express lbx2 later. In contrast, lbx1b expression first appears lateral to the somites at late segmentation stages and is later restricted to fin muscle. Morpholino knockdown of Lbx1b and Lbx2 suppresses hypaxial muscle development. Moreover, knockdown of Lbx2 results in malformation of muscle fibers and reduced fusion of fast precursors, although no obvious effects on induction or specification are observed. Expression of myofilament genes, including actin and myosin, requires the engrailed repressor domain of Lbx2. Conclusion Our results elucidate a new function of Lbx2 as a regulator of myofibril formation.

  12. Boundary conditions for the formation of the Moon

    NARCIS (Netherlands)

    Reuver, Maarten; de Meijer, R. J.; ten Kate, I. L.; van Westrenen, W.

    2016-01-01

    Recent measurements of the chemical and isotopic composition of lunar samples indicate that the Moon's bulk composition shows great similarities with the composition of the silicate Earth. Moon formation models that attempt to explain these similarities make a wide variety of assumptions about the p

  13. Particle concentration and flux dynamics in the atmospheric boundary layer as the indicator of formation mechanism

    Directory of Open Access Journals (Sweden)

    J. Lauros

    2010-08-01

    Full Text Available We carried out column model simulations to study particle fluxes and deposition and to evaluate different particle formation mechanisms at a boreal forest site in Finland. We show that kinetic nucleation of sulphuric acid cannot be responsible for new particle formation alone as the vertical profile of particle number distribution does not correspond to observations. Instead organic induced nucleation leads to good agreement confirming the relevance of the aerosol formation mechanism including organic compounds emitted by biosphere.

    Simulation of aerosol concentration inside the atmospheric boundary layer during nucleation days shows highly dynamical picture, where particle formation is coupled with chemistry and turbulent transport. We have demonstrated suitability of our turbulent mixing scheme in reproducing most important characteristics of particle dynamics inside the atmospheric boundary layer. Deposition and particle flux simulations show that deposition affects noticeably only the smallest particles at the lowest part of the atmospheric boundary layer.

  14. The Role of Boundary Spanners in the Formation of Customer Attractiveness

    DEFF Research Database (Denmark)

    Hald, Kim Sundtoft

    2012-01-01

    This paper examines the question of how to understand the formation of suppliers perceived customer attractiveness. It argues that existing conceptualization of buyer–supplier relationships are too simplistic to understand the full complexity involved in the formation of such perceptions, and...... of action” is deployed. The analysis demonstrates how suppliers' formation of perceptions related to customer attractiveness can be understood as constituted through a set of discrete historical means/ends alignments and misalignments between boundary spanning roles in the involved organizations....

  15. On a price formation free boundary model by Lasry and Lions

    KAUST Repository

    Caffarelli, Luis A.

    2011-06-01

    We discuss global existence and asymptotic behaviour of a price formation free boundary model introduced by Lasry and Lions in 2007. Our results are based on a construction which transforms the problem into the heat equation with specially prepared initial datum. The key point is that the free boundary present in the original problem becomes the zero level set of this solution. Using the properties of the heat operator we can show global existence, regularity and asymptotic results of the free boundary. 2011 Académie des sciences.

  16. Surface transition on ice induced by the formation of a grain boundary.

    Directory of Open Access Journals (Sweden)

    Christian Pedersen

    Full Text Available Interfaces between individual ice crystals, usually referred to as grain boundaries, play an important part in many processes in nature. Grain boundary properties are, for example, governing the sintering processes in snow and ice which transform a snowpack into a glacier. In the case of snow sintering, it has been assumed that there are no variations in surface roughness and surface melting, when considering the ice-air interface of an individual crystal. In contrast to that assumption, the present work suggests that there is an increased probability of molecular surface disorder in the vicinity of a grain boundary. The conclusion is based on the first detailed visualization of the formation of an ice grain boundary. The visualization is enabled by studying ice crystals growing into contact, at temperatures between -20°C and -15°C and pressures of 1-2 Torr, using Environmental Scanning Electron Microscopy. It is observed that the formation of a grain boundary induces a surface transition on the facets in contact. The transition does not propagate across facet edges. The surface transition is interpreted as the spreading of crystal dislocations away from the grain boundary. The observation constitutes a qualitatively new finding, and can potentially increase the understanding of specific processes in nature where ice grain boundaries are involved.

  17. Hormonal Regulation of Tuber Formation in Potato

    NARCIS (Netherlands)

    Aksenova, N.P.; Sergeeva, L.; Kolachevskaya, O.O.; Romanov, G.A.

    2013-01-01

    Tubers of potato (Solanum tuberosum L.) plants serve as organs for vegetative propagation and stock of matter and energy for the next generation. Tuber formation is a complex process involving several successive stages: stolon formation and growth, induction of tuberization, tuber initiation and fur

  18. Nanocomposites with thermosetting matrix: structure formation at the interphase boundary

    Directory of Open Access Journals (Sweden)

    KOROLEV Evgenij Valerjevich

    2014-06-01

    Full Text Available Composites with thermosetting matrix are often characterized by elevated values of operational properties – flexural and compressive strength, resistance to aggressive environments, etc. At the same time the cost of most thermosets (particularly – epoxy resins is quite high. Because of this the area of application of polymer composites in construction is limited. One of such application is the creation of multifunctional coatings. The high cost of resin dictates the need to improve the operational properties to ensure economic efficiency. So far, the known way to improve the operational properties is to produce nanoscale interfacial layer between fine filler and matrix in block. This way proved to be effective, but mechanism of the improvement is still uncertain. There areat least two different theories – so-called «adhesion theory» and «theory of deformable layer». The investigation is complicated by the variety of oligomers, hardeners (crosslinking agents and precursors of nanomodifiers. It is becoming more common lately to use adducts of aliphatic amines and epoxy oligomers as hardeners. As precursors of nanomodifiers the organosilicon compounds with siloxane bond in the main chain can be successfully used. In this paper we present results of investigation of a model system comprised of oligomer, crosslinking agent and precursor. The analysis of structure is carried out by means of Raman spectroscopy and atomic force microscopy. It is shown that at gelation point modifier has no significant effect on the chemical composition of the curing products; nevertheless, the admixture of modifier reduces the regularity of the emerging three-dimensional spatial net of thermoset. After completion of curing process the irregular spatial grid is still present. This indicates that in composites admixture of organosilicon precursors may lead to the formation of transition layer with reduced modulus of elasticity. Such layer, in turn, causes stress

  19. MHD flow layer formation at boundaries of magnetic islands in tokamak plasmas

    International Nuclear Information System (INIS)

    Non-linear development of double tearing modes induced by electron viscosity is numerically simulated. MHD flow layers are demonstrated to merge in the development of the modes. The sheared flows are shown to lie just at the boundaries of the magnetic islands, and to have sufficient levels required for internal transport barrier (ITB) formation. Possible correlation between the layer formation and triggering of experimentally observed ITBs, preferentially formed in proximities of rational flux surfaces of low safety factors, is discussed. (author)

  20. Traveling waves and dynamical formation of autonomous pacemakers in a bistable medium with periodic boundary conditions

    Science.gov (United States)

    Shepelev, Igor A.; Vadivasova, Tatiana E.; Postnov, Dmitry E.

    2015-03-01

    The problem of spatiotemporal pattern formation in the wall of arterial vesselsmay be reduced to 1D or 2D models of nonlinear active medium. We address this problem using the discrete array of non-oscillating (bistable) active units. We show how the specific choice of initial conditions in a 1D model with periodic boundary conditions triggers the self-sustained behaviour. We reveal the core of observed effects being the dynamical formation of localized (few-element size) autonomous pacemakers.

  1. Inside-Out Planet Formation. III. Planet-disk interaction at the dead zone inner boundary

    OpenAIRE

    Hu, Xiao; Zhu, Zhaohuan; Tan, Jonathan C.; Chatterjee, Sourav

    2015-01-01

    The Kepler mission has discovered more than 4000 exoplanet candidates. Many are in systems with tightly packed inner planets. Inside-Out Planet Formation (IOPF) has been proposed to explain these systems. It involves sequential in situ planet formation at the local pressure maximum of a retreating dead zone inner boundary (DZIB). Pebbles accumulate at this pressure trap, which builds up a ring, and then a planet. The planet is expected to grow until it opens a gap, which helps to both truncat...

  2. Transcription rate and transcript length drive formation of chromosomal interaction domain boundaries.

    Science.gov (United States)

    Le, Tung Bk; Laub, Michael T

    2016-07-15

    Chromosomes in all organisms are highly organized and divided into multiple chromosomal interaction domains, or topological domains. Regions of active, high transcription help establish and maintain domain boundaries, but precisely how this occurs remains unclear. Here, using fluorescence microscopy and chromosome conformation capture in conjunction with deep sequencing (Hi-C), we show that in Caulobacter crescentus, both transcription rate and transcript length, independent of concurrent translation, drive the formation of domain boundaries. We find that long, highly expressed genes do not form topological boundaries simply through the inhibition of supercoil diffusion. Instead, our results support a model in which long, active regions of transcription drive local decompaction of the chromosome, with these more open regions of the chromosome forming spatial gaps in vivo that diminish contacts between DNA in neighboring domains. These insights into the molecular forces responsible for domain formation in Caulobacter likely generalize to other bacteria and possibly eukaryotes. PMID:27288403

  3. Epigenetic Regulation of Memory Formation and Maintenance

    Science.gov (United States)

    Zovkic, Iva B.; Guzman-Karlsson, Mikael C.; Sweatt, J. David

    2013-01-01

    Understanding the cellular and molecular mechanisms underlying the formation and maintenance of memories is a central goal of the neuroscience community. It is well regarded that an organism's ability to lastingly adapt its behavior in response to a transient environmental stimulus relies on the central nervous system's capability for structural…

  4. Formation and Regulation of Mitochondrial Membranes

    Directory of Open Access Journals (Sweden)

    Laila Cigana Schenkel

    2014-01-01

    Full Text Available Mitochondrial membrane phospholipids are essential for the mitochondrial architecture, the activity of respiratory proteins, and the transport of proteins into the mitochondria. The accumulation of phospholipids within mitochondria depends on a coordinate synthesis, degradation, and trafficking of phospholipids between the endoplasmic reticulum (ER and mitochondria as well as intramitochondrial lipid trafficking. Several studies highlight the contribution of dietary fatty acids to the remodeling of phospholipids and mitochondrial membrane homeostasis. Understanding the role of phospholipids in the mitochondrial membrane and their metabolism will shed light on the molecular mechanisms involved in the regulation of mitochondrial function and in the mitochondrial-related diseases.

  5. 20 CFR 632.3 - Format for these regulations.

    Science.gov (United States)

    2010-04-01

    ... Indian programs under title II-B of the Act are set forth in 20 CFR part 632. This part in conjunction... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Format for these regulations. 632.3 Section... NATIVE AMERICAN EMPLOYMENT AND TRAINING PROGRAMS Introduction § 632.3 Format for these...

  6. Synapse formation is regulated by the signaling adaptor GIT1

    OpenAIRE

    Zhang, Huaye; Webb, Donna J.; Asmussen, Hannelore; Horwitz, Alan F.

    2003-01-01

    Dendritic spines in the central nervous system undergo rapid actin-based shape changes, making actin regulators potential modulators of spine morphology and synapse formation. Although several potential regulators and effectors for actin organization have been identified, the mechanisms by which these molecules assemble and localize are not understood. Here we show that the G protein–coupled receptor kinase–interacting protein (GIT)1 serves such a function by targeting actin regulators and lo...

  7. Formation of Structured Dayside Boundary Layers under Different Solar Wind Conditions: THEMIS Observations

    Science.gov (United States)

    Avanov, Levon A.; Chandler, Michael O.

    2008-01-01

    We have begun an investigation of the formation of the dayside low latitude boundary layer under different solar wind conditions using data from the THEMIS spacecraft. We present two cases of magnetopause/LLBL interface crossings made by the five spacecraft; one under long lasting northward IMF and a second for a period of southward IMF. All spacecraft during these observations traversed the dayside magnetosphere in a string-of-pearls configuration with the farthest distance between spacecraft less than approx.2 R(sub E). The sequence of observations from spacecraft, as they crossed the magnetopause, shows the development of a highly structured boundary layer regardless of the polarity of the IMF. We discuss possible scenarios for the development of such structured boundary layers, including low latitude reconnection under northward IMF as well as double reconnection in opposite hemispheres.

  8. Formation of self-regulation culture of physical education faculty

    Directory of Open Access Journals (Sweden)

    Kudin S.F.

    2016-02-01

    Full Text Available Purpose: to experimentally substantiate effectiveness of pedagogic conditions of self-regulation culture formation of future physical culture teachers. Material: in the research 110 3rd year students of physical education faculty participated. The students were questioned. The level of students’ anxiety was assessed. Results: Implementation of the author’s course in educational process facilitated formation of students’ self-regulation skills and abilities; raises confidence and self estimation; influences positively on functional state. It was found that students acquire ability to consciously observe their own verbal constructs of negative thinking and create positive alternatives. Conclusions: preparing of future physical culture teachers stipulates his (her ability to effectively fulfill professional functioning in the aspect of health preservation. The necessary conditions of self-regulation culture formation are formation of students’ holistic value-meaningful attitude to individual health and health of surrounding people.

  9. Influence of slip localization on surface relief formation and grain boundary microcrack nucleation

    International Nuclear Information System (INIS)

    Slip localization is often observed in metallic polycrystals after cyclic deformation (persistent slip bands) or pre-irradiation followed by tensile deformation (channels). To evaluate its influence on surface relief formation and grain boundary microcrack nucleation, crystalline finite element (FE) computations are carried out using microstructure inputs (slip band aspect ratio/spacing). Slip bands (low critical resolved shear stress (CRSS)) are embedded in small elastic aggregates. Slip band aspect ratio and neighboring grain orientations influence strongly the surface slips. But only a weak effect of slip band CRSS, spacing and grain boundary orientation is observed. Analytical formulae are deduced which allow an easy prediction of the surface and bulk slips. The computed slips are in agreement with experimental measures (AFM/TEM measures on pre-irradiated austenitic stainless steels and nickel, copper and precipitate-strengthened alloy subjected to cyclic loading). Grain boundary normal stresses are computed for various materials and loading conditions. A square root dependence with respect to the distance to the slip band corner is found similarly to the pile-up stress field. But the equivalent stress intensity factor is considerably lower. Analytical formulae are proposed for predicting the grain boundary normal stress field depending on the microstructure lengths. Finally, an energy balance criterion is applied using the equivalent elastic energy release rate and the surface/grain boundary energies. The predicted macroscopic stresses for microcrack nucleation are compared to the experimental ones. (authors)

  10. Zigzag Inversion Domain Boundaries in Indium Zinc Oxide-Based Nanowires: Structure and Formation

    OpenAIRE

    Goldstein, Anna P.

    2014-01-01

    Existing models for the crystal structure of indium zinc oxide (IZO) and indium iron zinc oxide (IFZO) conflict with electron microscopy data. We propose a model based on imaging and spectroscopy of IZO and IFZO nanowires and verify it using density functional theory. The model features a {12?1} ?zigzag? layer, which is an inversion domain boundary containing 5-coordinate indium and/or iron atoms. Higher values are observed for greater proportion of iron. We suggest a mechanism of formation i...

  11. Molecular-beam epitaxy of monolayer MoSe2: growth characteristics and domain boundary formation

    Science.gov (United States)

    Jiao, L.; Liu, H. J.; Chen, J. L.; Yi, Y.; Chen, W. G.; Cai, Y.; Wang, J. N.; Dai, X. Q.; Wang, N.; Ho, W. K.; Xie, M. H.

    2015-05-01

    Monolayer (ML) transition metal dichalcogenides (TMDs) are of great research interest due to their potential use in ultrathin electronic and optoelectronic applications. They show promise in new concept devices in spintronics and valleytronics. Here we present a growth study by molecular-beam epitaxy of ML and sub-ML MoSe2, an important member of TMDs, revealing its unique growth characteristics as well as the formation processes of domain boundary (DB) defects. A dramatic effect of growth temperature and post-growth annealing on DB formation is uncovered.

  12. Thermodynamic analysis of carbon formation boundary and reforming performance for steam reforming of dimethyl ether

    Science.gov (United States)

    Faungnawakij, Kajornsak; Kikuchi, Ryuji; Eguchi, Koichi

    Thermodynamic analysis of dimethyl ether steam reforming (DME SR) was investigated for carbon formation boundary, DME conversion, and hydrogen yield for fuel cell application. The equilibrium calculation employing Gibbs free minimization was performed to figure out the required steam-to-carbon ratio (S/C = 0-5) and reforming temperature (25-1000 °C) where coke formation was thermodynamically unfavorable. S/C, reforming temperature and product species strongly contributed to the coke formation and product composition. When chemical species DME, methanol, CO 2, CO, H 2, H 2O and coke were considered, complete conversion of DME and hydrogen yield above 78% without coke formation were achieved at the normal operating temperatures of molten carbonate fuel cell (600 °C) and solid oxide fuel cell (900 °C), when S/C was at or above 2.5. When CH 4 was favorable, production of coke and that of hydrogen were significantly suppressed.

  13. The Formation of Boundary Clinopyroxenes and Associated Glass Veins in Type B1 CAIs

    Energy Technology Data Exchange (ETDEWEB)

    Paque, J M; Beckett, J R; Ishii, H A; Toppani, A; Burnett, D S; Teslich, N; Dai, Z R; Bradley, J P

    2008-05-18

    We used focused ion beam thin section preparation and scanning transmission electron microscopy (FIB/STEM) to examine the interfacial region between spinel and host melilite for three spinel grains, two from the mantle and one from the core of an Allende type B1 inclusion, and a second pair of spinel grains from a type B1 inclusion from the Leoville carbonaceous chondrite. The compositions of boundary clinopyroxenes decorating spinel surfaces are generally consistent with those of coarser clinopyroxenes from the same region of the inclusion, suggesting little movement of spinels between mantle and core regions after the formation of boundary clinopyroxenes. The host melilite displays no anomalous compositions near the interface, and anorthite or other late-stage minerals are not observed, suggesting that crystallization of residual liquid was not responsible for the formation of boundary clinopyroxenes. Allende spinels display either direct spinel-melilite contact or an intervening boundary clinopyroxene between the two phases. In the core, boundary clinopyroxene is mantled by a thin (1-2 {micro}m thick) layer of normally zoned (X{sub Ak} increasing away from the melilite-clinopyroxene contact) melilite with X{sub Ak} matching that of the host melilite at the melilite-melilite contact. In the mantle, X{sub Ak} near boundary spinels is constant. Spinels in a Leoville type B1 inclusion are more complex with boundary clinopyroxene, as observed in Allende, but also variable amounts of glass ({approx}1 {micro}m width), secondary calcite, perovskite, and an unknown Mg-, Al-, OH-rich and Ca-, Si-poor crystalline phase that may be a layered double hydrate. Glass compositions are consistent to first order with a precursor consisting mostly of Mg-carpholite or sudoite with some aluminous diopside. One possible scenario of formation for the glass veins is that open system alteration of melilite produced a porous, hydrated aggregate of Mg-carpholite or sudoite + aluminous

  14. Black hole formation in AdS and thermalization on the boundary

    International Nuclear Information System (INIS)

    We investigate black hole formation by a spherically collapsing thin shell of matter in AdS space. This process has been suggested to have a holographic interpretation as thermalization of the CFT on the boundary of the AdS space. The AdS/CFT duality relates the shell in the bulk to an off-equilibrium state of the boundary theory which evolves towards a thermal equilibrium when the shell collapses to a black hole. We use 2-point functions to obtain information about the spectrum of excitations in the off-equilibrium state, and discuss how it characterizes the approach towards thermal equilibrium. The full holographic interpretation of the gravitational collapse would require a kinetic theory of the CFT at strong coupling. We speculate that the kinetic equations should be interpreted as a holographic dual of the equation of motion of the collapsing shell. (author)

  15. On the Formation Mechanisms of Artificially Generated High Reynolds Number Turbulent Boundary Layers

    Science.gov (United States)

    Rodríguez-López, Eduardo; Bruce, Paul J. K.; Buxton, Oliver R. H.

    2016-08-01

    We investigate the evolution of an artificially thick turbulent boundary layer generated by two families of small obstacles (divided into uniform and non-uniform wall normal distributions of blockage). One- and two-point velocity measurements using constant temperature anemometry show that the canonical behaviour of a boundary layer is recovered after an adaptation region downstream of the trips presenting 150~% higher momentum thickness (or equivalently, Reynolds number) than the natural case for the same downstream distance (x≈ 3 m). The effect of the degree of immersion of the trips for h/δ ≳ 1 is shown to play a secondary role. The one-point diagnostic quantities used to assess the degree of recovery of the canonical properties are the friction coefficient (representative of the inner motions), the shape factor and wake parameter (representative of the wake regions); they provide a severe test to be applied to artificially generated boundary layers. Simultaneous two-point velocity measurements of both spanwise and wall-normal correlations and the modulation of inner velocity by the outer structures show that there are two different formation mechanisms for the boundary layer. The trips with high aspect ratio and uniform distributed blockage leave the inner motions of the boundary layer relatively undisturbed, which subsequently drive the mixing of the obstacles' wake with the wall-bounded flow (wall-driven). In contrast, the low aspect-ratio trips with non-uniform blockage destroy the inner structures, which are then re-formed further downstream under the influence of the wake of the trips (wake-driven).

  16. Leptin regulates bone formation via the sympathetic nervous system

    Science.gov (United States)

    Takeda, Shu; Elefteriou, Florent; Levasseur, Regis; Liu, Xiuyun; Zhao, Liping; Parker, Keith L.; Armstrong, Dawna; Ducy, Patricia; Karsenty, Gerard

    2002-01-01

    We previously showed that leptin inhibits bone formation by an undefined mechanism. Here, we show that hypothalamic leptin-dependent antiosteogenic and anorexigenic networks differ, and that the peripheral mediators of leptin antiosteogenic function appear to be neuronal. Neuropeptides mediating leptin anorexigenic function do not affect bone formation. Leptin deficiency results in low sympathetic tone, and genetic or pharmacological ablation of adrenergic signaling leads to a leptin-resistant high bone mass. beta-adrenergic receptors on osteoblasts regulate their proliferation, and a beta-adrenergic agonist decreases bone mass in leptin-deficient and wild-type mice while a beta-adrenergic antagonist increases bone mass in wild-type and ovariectomized mice. None of these manipulations affects body weight. This study demonstrates a leptin-dependent neuronal regulation of bone formation with potential therapeutic implications for osteoporosis.

  17. Misorientation effect of grain boundary on the formation of discontinuous precipitation in second and third generation single crystal superalloys

    Directory of Open Access Journals (Sweden)

    Yu Zhengrong

    2014-01-01

    Full Text Available [001] tilt artificial grain boundaries of Ni-based single crystal superalloys CMSX-4 and DD10 have been prepared by self-diffusion bonding. The microstructural stability of 0 ∼ 30∘ artificial grain boundaries have been investigated after heat treatment at 1100 ∘C for 0 ∼ 300 h. TCP phases and cellular colony developed on boundaries are related to misorientation angle of the bonded boundaries of DD10 and DD10 alloys as well as the bonded boundaries of CMSX-4 and DD10 alloys. The heterogeneous nucleation of TCP phase, enveloped by γ′ film, occurred along 15∘ and 20∘ boundaries. Discontinuous Precipitation (DP reaction occurred along high misorientation angle (20∘∼ 30∘ boundaries. However, no TCP phase formation existed along grain boundaries with different misorientation angles in CMSX-4/CMSX-4 bonded alloys as well as for a 0∘ boundary in DD10/DD10 and CMSX-4/DD10 bonded alloys. The current study clearly suggests that grain boundary precipitation and its morphology were influenced by the misorientation angle of grain boundary and the content of refractory elements in alloy.

  18. Inside-Out Planet Formation. III. Planet-disk interaction at the dead zone inner boundary

    CERN Document Server

    Hu, Xiao; Tan, Jonathan C; Chatterjee, Sourav

    2015-01-01

    The Kepler mission has discovered more than 4000 exoplanet candidates. Many are in systems with tightly packed inner planets. Inside-Out Planet Formation (IOPF) has been proposed to explain these systems. It involves sequential in situ planet formation at the local pressure maximum of a retreating dead zone inner boundary (DZIB). Pebbles accumulate at this pressure trap, which builds up a ring, and then a planet. The planet is expected to grow until it opens a gap, which helps to both truncate pebble accretion and induce DZIB retreat that sets the location of formation of the next planet. This simple scenario may be modified if the planet migrates significantly from its formation location. Thus planet-disk interactions play a crucial role in the IOPF scenario. We present numerical simulations that first assess migration of planets of various masses that are forming at the DZIB of an active accretion disk, where the effective viscosity rapidly increases in the radially inward direction. We find that the disk's...

  19. Instantons near a tachyonic top in an anti de Sitter and the no-boundary regulator

    Science.gov (United States)

    Lee, Bum-Hoon; Lee, Wonwoo; Ro, Daeho; Yeom, Dong-han

    2015-08-01

    We investigate instantons near a tachyonic top in an anti de Sitter (AdS) background. If the mass scale around the hill-top is above the Breitenlohner-Freedman (BF) bound, then the top is classically stable. When the BF bound is satisfied, it is already known that there can exist instantons with a non-zero probability, though fine-tunings of the potential are required. On the other hand, we may consider a possibility to obtain instantons with a non-zero probability for a more natural shape of potentials. We found that the no-boundary regulator is useful to assign a non-zero probability for general instantons near the tachyonic top with a consistent framework. To use the no-boundary regulator, we need to introduce the complexification of fields. One interesting feature is that, for these AdS instantons, the classicality may not be satisfied after the Wick rotation and hence after the nucleation. This magnifies a novel difference between dS and AdS; a semi-classical boundary observer in AdS may notice the dispersion of quantum fields as a kind of uncertainty, while every semi-classical observer in dS is classicalized individually and hence there is no semi-classical observer who can see the quantum dispersion of the scalar field.

  20. Vesicle Size Regulates Nanotube Formation in the Cell

    OpenAIRE

    Qian Peter Su; Wanqing Du; Qinghua Ji; Boxin Xue; Dong Jiang; Yueyao Zhu; Jizhong Lou; Li Yu; Yujie Sun

    2016-01-01

    Intracellular membrane nanotube formation and its dynamics play important roles for cargo transportation and organelle biogenesis. Regarding the regulation mechanisms, while much attention has been paid on the lipid composition and its associated protein molecules, effects of the vesicle size has not been studied in the cell. Giant unilamellar vesicles (GUVs) are often used for in vitro membrane deformation studies, but they are much larger than most intracellular vesicles and the in vitro st...

  1. Chromatin boundary elements organize genomic architecture and developmental gene regulation in Drosophila Hox clusters.

    Science.gov (United States)

    Ma, Zhibo; Li, Mo; Roy, Sharmila; Liu, Kevin J; Romine, Matthew L; Lane, Derrick C; Patel, Sapna K; Cai, Haini N

    2016-08-26

    The three-dimensional (3D) organization of the eukaryotic genome is critical for its proper function. Evidence suggests that extensive chromatin loops form the building blocks of the genomic architecture, separating genes and gene clusters into distinct functional domains. These loops are anchored in part by a special type of DNA elements called chromatin boundary elements (CBEs). CBEs were originally found to insulate neighboring genes by blocking influences of transcriptional enhancers or the spread of silent chromatin. However, recent results show that chromatin loops can also play a positive role in gene regulation by looping out intervening DNA and "delivering" remote enhancers to gene promoters. In addition, studies from human and model organisms indicate that the configuration of chromatin loops, many of which are tethered by CBEs, is dynamically regulated during cell differentiation. In particular, a recent work by Li et al has shown that the SF1 boundary, located in the Drosophila Hox cluster, regulates local genes by tethering different subsets of chromatin loops: One subset enclose a neighboring gene ftz, limiting its access by the surrounding Scr enhancers and restrict the spread of repressive histones during early embryogenesis; and the other loops subdivide the Scr regulatory region into independent domains of enhancer accessibility. The enhancer-blocking activity of these CBE elements varies greatly in strength and tissue distribution. Further, tandem pairing of SF1 and SF2 facilitate the bypass of distal enhancers in transgenic flies, providing a mechanism for endogenous enhancers to circumvent genomic interruptions resulting from chromosomal rearrangement. This study demonstrates how a network of chromatin boundaries, centrally organized by SF1, can remodel the 3D genome to facilitate gene regulation during development. PMID:27621770

  2. Chromatin boundary elements organize genomic architecture and developmental gene regulation in Drosophila Hox clusters

    Science.gov (United States)

    Ma, Zhibo; Li, Mo; Roy, Sharmila; Liu, Kevin J; Romine, Matthew L; Lane, Derrick C; Patel, Sapna K; Cai, Haini N

    2016-01-01

    The three-dimensional (3D) organization of the eukaryotic genome is critical for its proper function. Evidence suggests that extensive chromatin loops form the building blocks of the genomic architecture, separating genes and gene clusters into distinct functional domains. These loops are anchored in part by a special type of DNA elements called chromatin boundary elements (CBEs). CBEs were originally found to insulate neighboring genes by blocking influences of transcriptional enhancers or the spread of silent chromatin. However, recent results show that chromatin loops can also play a positive role in gene regulation by looping out intervening DNA and “delivering” remote enhancers to gene promoters. In addition, studies from human and model organisms indicate that the configuration of chromatin loops, many of which are tethered by CBEs, is dynamically regulated during cell differentiation. In particular, a recent work by Li et al has shown that the SF1 boundary, located in the Drosophila Hox cluster, regulates local genes by tethering different subsets of chromatin loops: One subset enclose a neighboring gene ftz, limiting its access by the surrounding Scr enhancers and restrict the spread of repressive histones during early embryogenesis; and the other loops subdivide the Scr regulatory region into independent domains of enhancer accessibility. The enhancer-blocking activity of these CBE elements varies greatly in strength and tissue distribution. Further, tandem pairing of SF1 and SF2 facilitate the bypass of distal enhancers in transgenic flies, providing a mechanism for endogenous enhancers to circumvent genomic interruptions resulting from chromosomal rearrangement. This study demonstrates how a network of chromatin boundaries, centrally organized by SF1, can remodel the 3D genome to facilitate gene regulation during development.

  3. Formation and Regulation of Adaptive Response in Nematode Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Y.-L. Zhao

    2012-01-01

    Full Text Available All organisms respond to environmental stresses (e.g., heavy metal, heat, UV irradiation, hyperoxia, food limitation, etc. with coordinated adjustments in order to deal with the consequences and/or injuries caused by the severe stress. The nematode Caenorhabditis elegans often exerts adaptive responses if preconditioned with low concentrations of agents or stressor. In C. elegans, three types of adaptive responses can be formed: hormesis, cross-adaptation, and dietary restriction. Several factors influence the formation of adaptive responses in nematodes, and some mechanisms can explain their response formation. In particular, antioxidation system, heat-shock proteins, metallothioneins, glutathione, signaling transduction, and metabolic signals may play important roles in regulating the formation of adaptive responses. In this paper, we summarize the published evidence demonstrating that several types of adaptive responses have converged in C. elegans and discussed some possible alternative theories explaining the adaptive response control.

  4. Formation of magnetic filaments at the boundaries of the magnetospheres of solar system planets

    International Nuclear Information System (INIS)

    The theory of localized spontaneous reconnection at the boundaries of the magnetospheres of solar-system planets with strong intrinsic magnetic field is given in the paper. Such forms of reconnection (flux transfer events - FTE) resulting in formation of magnetic filaments are observed by sattelites near the magnetosphgeres of Mercury, Earth and Jupiter. The physical factors controlling the temporal and spatial scales of this phenomenon in dependence on the distance from the Sun (the parameters of the solar wind) and the planetary magnetic dipole moment are discussed. the theoretical estimates of characteristic diameters of magnetic filaments λE ∼ 5000 km, λM ∼ 500 km, λJ ∼ 13000 km for the Earth, Mercury and Jupiter agree satisfactorily with the experimental data. In conclusion, the typical FTE parameters for Saturn and some other astrophysical objects are evaluated

  5. Quorum-sensing regulates biofilm formation in Vibrio scophthalmi

    Directory of Open Access Journals (Sweden)

    García-Aljaro Cristina

    2012-12-01

    Full Text Available Abstract Background In a previous study, we demonstrated that Vibrio scophthalmi, the most abundant Vibrio species among the marine aerobic or facultatively anaerobic bacteria inhabiting the intestinal tract of healthy cultured turbot (Scophthalmus maximus, contains at least two quorum-sensing circuits involving two types of signal molecules (a 3-hydroxy-dodecanoyl-homoserine lactone and the universal autoinducer 2 encoded by luxS. The purpose of this study was to investigate the functions regulated by these quorum sensing circuits in this vibrio by constructing mutants for the genes involved in these circuits. Results The presence of a homologue to the Vibrio harveyi luxR gene encoding a main transcriptional regulator, whose expression is modulated by quorum–sensing signal molecules in other vibrios, was detected and sequenced. The V. scophthalmi LuxR protein displayed a maximum amino acid identity of 82% with SmcR, the LuxR homologue found in Vibrio vulnificus. luxR and luxS null mutants were constructed and their phenotype analysed. Both mutants displayed reduced biofilm formation in vitro as well as differences in membrane protein expression by mass-spectrometry analysis. Additionally, a recombinant strain of V. scophthalmi carrying the lactonase AiiA from Bacillus cereus, which causes hydrolysis of acyl homoserine lactones, was included in the study. Conclusions V. scophthalmi shares two quorum sensing circuits, including the main transcriptional regulator luxR, with some pathogenic vibrios such as V. harveyi and V. anguillarum. However, contrary to these pathogenic vibrios no virulence factors (such as protease production were found to be quorum sensing regulated in this bacterium. Noteworthy, biofilm formation was altered in luxS and luxR mutants. In these mutants a different expression profile of membrane proteins were observed with respect to the wild type strain suggesting that quorum sensing could play a role in the regulation of

  6. Vesicle Size Regulates Nanotube Formation in the Cell

    Science.gov (United States)

    Su, Qian Peter; Du, Wanqing; Ji, Qinghua; Xue, Boxin; Jiang, Dong; Zhu, Yueyao; Lou, Jizhong; Yu, Li; Sun, Yujie

    2016-01-01

    Intracellular membrane nanotube formation and its dynamics play important roles for cargo transportation and organelle biogenesis. Regarding the regulation mechanisms, while much attention has been paid on the lipid composition and its associated protein molecules, effects of the vesicle size has not been studied in the cell. Giant unilamellar vesicles (GUVs) are often used for in vitro membrane deformation studies, but they are much larger than most intracellular vesicles and the in vitro studies also lack physiological relevance. Here, we use lysosomes and autolysosomes, whose sizes range between 100 nm and 1 μm, as model systems to study the size effects on nanotube formation both in vivo and in vitro. Single molecule observations indicate that driven by kinesin motors, small vesicles (100–200 nm) are mainly transported along the tracks while a remarkable portion of large vesicles (500–1000 nm) form nanotubes. This size effect is further confirmed by in vitro reconstitution assays on liposomes and purified lysosomes and autolysosomes. We also apply Atomic Force Microscopy (AFM) to measure the initiation force for nanotube formation. These results suggest that the size-dependence may be one of the mechanisms for cells to regulate cellular processes involving membrane-deformation, such as the timing of tubulation-mediated vesicle recycling. PMID:27052881

  7. Impact of the landscape evolution on the hydraulic boundary conditions of the Callovo-Oxfordian formation

    Energy Technology Data Exchange (ETDEWEB)

    Teles, V.; Maugis, P.; Mouche, E. [CEA, CNRS Orme Merisiers, Lab Sci Climat and Environm, F-91191 Gif Sur Yvette, (France); Brulhet, J.; Wendling, J.; Vigneron, G. [ANDRA, F-92298 Chatenay Malabry, (France)

    2007-07-01

    The Callovo-Oxfordian formation in the Eastern part of France was recognized as a potential nuclear waste repository layer. The ANDRA (National Agency for Nuclear Waste Management) has launched a few years ago a research program that aims to define the mechanisms of importance in the impact of the surface environment evolution on the site hydrogeology. Based on mapping and dating results, ANDRA has quantified the geomorphological evolution of the Meuse/Haute-Marne site in the past and has estimated the future evolution over 1 million years. The Callovo-Oxfordian boundary conditions depend on the hydraulic heads in the two surrounding aquifers, the Oxfordian limestone above, and the Dogger one, below. Both aquifer outcrops are modified over the next million years. For the present study, the geo-morphologic evolution is considered independently of other processes and translated in the hydrogeological model in terms of changes in the hydraulic boundary conditions at the surface. The hydrodynamic simulations have been performed with the code Cast3M (implemented by CEA (Atomic Energy Commissariat)) using a mixed hybrid finite-element formulation. For these groundwater flow simulations, three modelled stages are presented: the Present, 500,000 years (500 Ky) and 10{sup 6} years (1 Ma) in the future. The landscape evolution is merely considered through the use of three different topographies on which the boundary conditions are applied. According to ANDRA predictions, at the Meuse/Haute-Marne site, the valley incisions on the Bure plateau will locally reach the Oxfordian limestone. Thus, the Oxfordian aquifer exhibits more changes due to topographic evolution than the Dogger aquifer. Hydrodynamic simulations show a significant impact of the valley incisions on the groundwater flow by the creation of local outlets to the Oxfordian limestone aquifer in the North of the area for the 1 My topography. It induces local perturbations of the saturation level. The global erosion

  8. Homeostatic regulation of meiotic DSB formation by ATM/ATR

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Tim J.; Wardell, Kayleigh; Garcia, Valerie; Neale, Matthew J., E-mail: m.neale@sussex.ac.uk

    2014-11-15

    Ataxia–telangiectasia mutated (ATM) and RAD3-related (ATR) are widely known as being central players in the mitotic DNA damage response (DDR), mounting responses to DNA double-strand breaks (DSBs) and single-stranded DNA (ssDNA) respectively. The DDR signalling cascade couples cell cycle control to damage-sensing and repair processes in order to prevent untimely cell cycle progression while damage still persists [1]. Both ATM/ATR are, however, also emerging as essential factors in the process of meiosis; a specialised cell cycle programme responsible for the formation of haploid gametes via two sequential nuclear divisions. Central to achieving accurate meiotic chromosome segregation is the introduction of numerous DSBs spread across the genome by the evolutionarily conserved enzyme, Spo11. This review seeks to explore and address how cells utilise ATM/ATR pathways to regulate Spo11-DSB formation, establish DSB homeostasis and ensure meiosis is completed unperturbed.

  9. Vinculin-dependent Cadherin mechanosensing regulates efficient epithelial barrier formation

    Directory of Open Access Journals (Sweden)

    Floor Twiss

    2012-09-01

    Proper regulation of the formation and stabilization of epithelial cell–cell adhesion is crucial in embryonic morphogenesis and tissue repair processes. Defects in this process lead to organ malformation and defective epithelial barrier function. A combination of chemical and mechanical cues is used by cells to drive this process. We have investigated the role of the actomyosin cytoskeleton and its connection to cell–cell junction complexes in the formation of an epithelial barrier in MDCK cells. We find that the E-cadherin complex is sufficient to mediate a functional link between cell–cell contacts and the actomyosin cytoskeleton. This link involves the actin binding capacity of α-catenin and the recruitment of the mechanosensitive protein Vinculin to tensile, punctate cell–cell junctions that connect to radial F-actin bundles, which we name Focal Adherens Junctions (FAJ. When cell–cell adhesions mature, these FAJs disappear and linear junctions are formed that do not contain Vinculin. The rapid phase of barrier establishment (as measured by Trans Epithelial Electrical Resistance (TER correlates with the presence of FAJs. Moreover, the rate of barrier establishment is delayed when actomyosin contraction is blocked or when Vinculin recruitment to the Cadherin complex is prevented. Enhanced presence of Vinculin increases the rate of barrier formation. We conclude that E-cadherin-based FAJs connect forming cell–cell adhesions to the contractile actomyosin cytoskeleton. These specialized junctions are sites of Cadherin mechanosensing, which, through the recruitment of Vinculin, is a driving force in epithelial barrier formation.

  10. Laminin 5 regulates polycystic kidney cell proliferation and cyst formation.

    Science.gov (United States)

    Joly, Dominique; Berissi, Sophie; Bertrand, Amélie; Strehl, Laetitia; Patey, Natacha; Knebelmann, Bertrand

    2006-09-29

    Renal cyst formation is the hallmark of autosomal dominant polycystic kidney disease (ADPKD). ADPKD cyst-lining cells have an increased proliferation rate and are surrounded by an abnormal extracellular matrix (ECM). We have previously shown that Laminin 5 (Ln-5, a alpha(3)beta(3)gamma(2) trimer) is aberrantly expressed in the pericystic ECM of ADPKD kidneys. We report that ADPKD cells in primary cultures produce and secrete Ln-5 that is incorporated to the pericystic ECM in an in vitro model of cystogenesis. In monolayers, purified Ln-5 induces ERK activation and proliferation of ADPKD cells, whereas upon epidermal growth factor stimulation blocking endogenously produced Ln-5 with anti-gamma(2) chain antibody reduces the sustained ERK activation and inhibits proliferation. In three-dimensional gel culture, addition of purified Ln-5 stimulates cell proliferation and cyst formation, whereas blocking endogenous Ln-5 strongly inhibits cyst formation. Ligation of alpha(6)beta(4) integrin, a major Ln-5 receptor aberrantly expressed by ADPKD cells, induces beta(4) integrin phosphorylation, ERK activation, cell proliferation, and cyst formation. These findings indicate that Ln-5 is an important regulator of ADPKD cell proliferation and cystogenesis and suggest that Ln-5 gamma(2) chain and Ln-5-alpha(6)beta(4) integrin interaction both contribute to these phenotypic changes. PMID:16870608

  11. Soil-plant-atmosphere conditions regulating convective cloud formation above southeastern US pine plantations.

    Science.gov (United States)

    Manoli, Gabriele; Domec, Jean-Christophe; Novick, Kimberly; Oishi, Andrew Christopher; Noormets, Asko; Marani, Marco; Katul, Gabriel

    2016-06-01

    Loblolly pine trees (Pinus taeda L.) occupy more than 20% of the forested area in the southern United States, represent more than 50% of the standing pine volume in this region, and remove from the atmosphere about 500 g C m-2 per year through net ecosystem exchange. Hence, their significance as a major regional carbon sink can hardly be disputed. What is disputed is whether the proliferation of young plantations replacing old forest in the southern United States will alter key aspects of the hydrologic cycle, including convective rainfall, which is the focus of the present work. Ecosystem fluxes of sensible (Hs) and latent heat (LE) and large-scale, slowly evolving free atmospheric temperature and water vapor content are known to be first-order controls on the formation of convective clouds in the atmospheric boundary layer. These controlling processes are here described by a zero-order analytical model aimed at assessing how plantations of different ages may regulate the persistence and transition of the atmospheric system between cloudy and cloudless conditions. Using the analytical model together with field observations, the roles of ecosystem Hs and LE on convective cloud formation are explored relative to the entrainment of heat and moisture from the free atmosphere. Our results demonstrate that cloudy-cloudless regimes at the land surface are regulated by a nonlinear relation between the Bowen ratio Bo=Hs/LE and root-zone soil water content, suggesting that young/mature pines ecosystems have the ability to recirculate available water (through rainfall predisposition mechanisms). Such nonlinearity was not detected in a much older pine stand, suggesting a higher tolerance to drought but a limited control on boundary layer dynamics. These results enable the generation of hypotheses about the impacts on convective cloud formation driven by afforestation/deforestation and groundwater depletion projected to increase following increased human population in the

  12. Regulation of Memory Formation by the Transcription Factor XBP1

    Directory of Open Access Journals (Sweden)

    Gabriela Martínez

    2016-02-01

    Full Text Available Contextual memory formation relies on the induction of new genes in the hippocampus. A polymorphism in the promoter of the transcription factor XBP1 was identified as a risk factor for Alzheimer’s disease and bipolar disorders. XBP1 is a major regulator of the unfolded protein response (UPR, mediating adaptation to endoplasmic reticulum (ER stress. Using a phenotypic screen, we uncovered an unexpected function of XBP1 in cognition and behavior. Mice lacking XBP1 in the nervous system showed specific impairment of contextual memory formation and long-term potentiation (LTP, whereas neuronal XBP1s overexpression improved performance in memory tasks. Gene expression analysis revealed that XBP1 regulates a group of memory-related genes, highlighting brain-derived neurotrophic factor (BDNF, a key component in memory consolidation. Overexpression of BDNF in the hippocampus reversed the XBP1-deficient phenotype. Our study revealed an unanticipated function of XBP1 in cognitive processes that is apparently unrelated to its role in ER stress.

  13. How stellar feedback simultaneously regulates star formation and drives outflows

    CERN Document Server

    Hayward, Christopher C

    2015-01-01

    We present an analytic model for how momentum deposition from stellar feedback simultaneously regulates star formation and drives outflows in a turbulent interstellar medium (ISM). Because the ISM is turbulent, a given patch of ISM exhibits sub-patches with a range of surface densities. The high-density patches are 'pushed' by feedback, thereby driving turbulence and self-regulating local star formation. Sufficiently low-density patches, however, are accelerated to above the escape velocity before the region can self-adjust and are thus vented as outflows. In the turbulent-pressure-supported regime, when the gas fraction is $\\gtrsim 0.3$, the ratio of the turbulent velocity dispersion to the circular velocity is sufficiently high that at any given time, of order half of the ISM has surface density less than the critical value and thus can be blown out on a dynamical time. The resulting outflows have a mass-loading factor ($\\eta \\equiv M_{\\rm out}/M_{\\star}$) that is inversely proportional to the gas fraction ...

  14. Engineering transcriptional regulation to control Pdu microcompartment formation.

    Directory of Open Access Journals (Sweden)

    Edward Y Kim

    Full Text Available Bacterial microcompartments (MCPs show great promise for the organization of engineered metabolic pathways within the bacterial cytoplasm. This subcellular organelle is composed of a protein shell of 100-200 nm diameter that natively encapsulates multi-enzyme pathways. The high energy cost of synthesizing the thousands of protein subunits required for each MCP demands precise regulation of MCP formation for both native and engineered systems. Here, we study the regulation of the propanediol utilization (Pdu MCP, for which growth on 1,2-propanediol induces expression of the Pdu operon for the catabolism of 1,2-propanediol. We construct a fluorescence-based transcriptional reporter to investigate the activation of the Ppdu promoter, which drives the transcription of 21 pdu genes. Guided by this reporter, we find that MCPs can be expressed in strains grown in rich media, provided that glucose is not present. We also characterize the response of the Ppdu promoter to a transcriptional activator of the pdu operon, PocR, and find PocR to be a necessary component of Pdu MCP formation. Furthermore, we find that MCPs form normally upon the heterologous expression of PocR even in the absence of the natural inducer 1,2-propanediol and in the presence of glucose, and that Pdu MCPs formed in response to heterologous PocR expression can metabolize 1,2-propanediol in vivo. We anticipate that this technique of overexpressing a key transcription factor may be used to study and engineer the formation, size, and/or number of MCPs for the Pdu and related MCP systems.

  15. Cyclic expression of lhx2 regulates hair formation.

    Directory of Open Access Journals (Sweden)

    Gunilla Törnqvist

    2010-04-01

    Full Text Available Hair is important for thermoregulation, physical protection, sensory activity, seasonal camouflage, and social interactions. Hair is generated in hair follicles (HFs and, following morphogenesis, HFs undergo cyclic phases of active growth (anagen, regression (catagen, and inactivity (telogen throughout life. The transcriptional regulation of this process is not well understood. We show that the transcription factor Lhx2 is expressed in cells of the outer root sheath and a subpopulation of matrix cells during both morphogenesis and anagen. As the HFs enter telogen, expression becomes undetectable and reappears prior to initiation of anagen in the secondary hair germ. In contrast to previously published results, we find that Lhx2 is primarily expressed by precursor cells outside of the bulge region where the HF stem cells are located. This developmental, stage- and cell-specific expression suggests that Lhx2 regulates the generation and regeneration of hair. In support of this hypothesis, we show that Lhx2 is required for anagen progression and HF morphogenesis. Moreover, transgenic expression of Lhx2 in postnatal HFs is sufficient to induce anagen. Thus, our results reveal an alternative interpretation of Lhx2 function in HFs compared to previously published results, since Lhx2 is periodically expressed, primarily in precursor cells distinct from those in the bulge region, and is an essential positive regulator of hair formation.

  16. An instability of feedback regulated star formation in galactic nuclei

    CERN Document Server

    Torrey, Paul; Faucher-Giguère, Claude-André; Vogelsberger, Mark; Quataert, Eliot; Kereš, Dušan; Murray, Norman

    2016-01-01

    We examine the stability of feedback-regulated star formation (SF) in galactic nuclei and contrast it to SF in extended discs. In galactic nuclei the dynamical time becomes shorter than the time over which feedback from young stars evolves. We argue analytically that the balance between stellar feedback and gravity is unstable in this regime. We study this using numerical simulations with pc-scale resolution and explicit stellar feedback taken from stellar evolution models. The nuclear gas mass, young stellar mass, and SFR within the central ~100 pc (the short-timescale regime) never reach steady-state, but instead go through dramatic, oscillatory cycles. Stars form until a critical surface density of young stars is present (such that feedback overwhelms gravity), at which point they begin to expel gas from the nucleus. Since the dynamical times are shorter than the stellar evolution times, the stars do not die as the gas is expelled, but continue to push, triggering a runaway quenching of star formation in t...

  17. Airborne observations of new particle formation events in the boundary layer using a Zeppelin

    Science.gov (United States)

    Lampilahti, Janne; Manninen, Hanna E.; Nieminen, Tuomo; Mirme, Sander; Pullinen, Iida; Yli-Juuti, Taina; Schobesberger, Siegfried; Kangasluoma, Juha; Kontkanen, Jenni; Lehtipalo, Katrianne; Ehn, Mikael; Mentel, Thomas F.; Petäjä, Tuukka; Kulmala, Markku

    2014-05-01

    Atmospheric new particle formation (NPF) is a frequent and ubiquitous process in the atmosphere and a major source of newly formed aerosol particles [1]. However, it is still unclear how the aerosol particle distribution evolves in space and time during an NPF. We investigated where in the planetary boundary layer does NPF begin and how does the aerosol number size distribution develop in space and time during it. We measured in Hyytiälä, southern Finland using ground based and airborne measurements. The measurements were part of the PEGASOS project. NPF was studied on six scientific flights during spring 2013 using a Zeppelin NT class airship. Ground based measurements were simultaneously conducted at SMEAR II station located in Hyytiälä. The flight profiles over Hyytiälä were flown between sunrise and noon during the growth of the boundary layer. The profiles over Hyytiälä covered vertically a distance of 100-1000 meters reaching the mixed layer, stable (nocturnal) boundary layer and the residual layer. Horizontally the profiles covered approximately a circular area of four kilometers in diameter. The measurements include particle number size distribution by Neutral cluster and Air Ion Spectrometer (NAIS), Differential Mobility Particle Sizer (DMPS) and Particle Size Magnifier (PSM) [2], meteorological parameters and position (latitude, longitude and altitude) of the Zeppelin. Beginning of NPF was determined from an increase in 1.7-3 nm ion concentration. Height of the mixed layer was estimated from relative humidity measured on-board the Zeppelin. Particle growth rate during NPF was calculated. Spatial inhomogeneities in particle number size distribution during NPF were located and the birthplace of the particles was estimated using the growth rate and trajectories. We observed a regional NPF event that began simultaneously and evolved uniformly inside the mixed layer. In the horizontal direction we observed a long and narrow high concentration plume of

  18. Self-Gravitating Relativistic Fluids: The Formation of a Free Phase Boundary in the Phase Transition from Hard to Soft

    CERN Document Server

    Christodoulou, Demetrios

    2014-01-01

    In the 1990's Christodoulou introduced an idealized fluid model intended to capture some of the features of the gravitational collapse of a massive star to form a neutron star or a black hole. This was the two-phase model introduced in 'Self-gravitating relativistic fluids: a two phase model', Arch. Rational Mech. Anal. 130, 343-400 (1995). The present work deals with the formation of a free phase boundary in the phase transition from hard to soft in this model. In this case the phase boundary has corners at the null points, the points which separate the timelike and spacelike components of the interface between the two phases. We prove existence and uniqueness of a free phase boundary. Also the local form of the shock near the null point is established.

  19. Suppression of drift wave turbulence and zonal flow formation by changing axial boundary conditions in a cylindrical magnetized plasma device

    International Nuclear Information System (INIS)

    For drift wave turbulence, due to charge conservation, the divergence of the parallel current is coupled to the divergence of the perpendicular polarization current, which determines the effective radial momentum flux, i.e., the Reynolds stress. Changes in the current flow patterns also affect the nonlinear energy transfer from smaller to larger scales. Here, we show that by changing the end plate boundary conditions in a cylindrical plasma device, the radial currents through the plasma and hence the net momentum transport and the nonlinear coupling for the inverse energy transfer are strongly modified. The transition to drift wave turbulence and the formation of low frequency zonal flows can be either suppressed with conducting boundaries or enhanced with insulating boundaries.

  20. Self-Gravitating Relativistic Fluids: The Formation of a Free Phase Boundary in the Phase Transition from Hard to Soft

    Science.gov (United States)

    Christodoulou, Demetrios; Lisibach, André

    2016-06-01

    In the 1990s Christodoulou introduced an idealized fluid model intended to capture some of the features of the gravitational collapse of a massive star to form a neutron star or a black hole. This was the two-phase model introduced in `Self-gravitating relativistic fluids: a two phase model' (Demeterios, Arch Ration Mech Anal 130:343-400, 1995). The present work deals with the formation of a free phase boundary in the phase transition from hard to soft in this model. In this case the phase boundary has corners at the null points; the points which separate the timelike and spacelike components of the interface between the two phases. We prove the existence and uniqueness of a free phase boundary. Also the local form of the shock near the null point is established.

  1. Formation of the thermal-driven boundary jet in an f-plane mesoscale basin

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The paper adopts an f-plane quasi-geostrophic inertial model without linearization to investigate the perturbation temperature, boundary jet and upwelling (downwelling) in an idealized rectangular basin, under the consideration of west side friction layer and heat conservation. There is net heat input on the upper surface and equal quality heat dissipation on the west boundary, and without heat exchange on other boundaries, then the heat is conservation in the whole basin. Results show that there is thermal front due to denseness of the perturbation temperature in the west side boundary, the perturbation pressure and flow field are reversal on the upper layer and bottom layer. On the bottom layer, the west coastal current is northward, and the maximum perturbation pressure center is on the west, however, on the upper layer, the east coastal current is southward, and the maximum perturbation pressure center is on the east. There is strong vertical flow in narrow western boundary layer, and also in the central zone. The effect of different upper thermal forcings is also studied, and it can be concluded that there is always temperature denseness and boundary jet near the west boundary, and the appearance of flow field reversal, but the distribution of vertical flow is rather different.

  2. vox homeobox gene: a novel regulator of midbrain-hindbrain boundary development in medaka fish?

    Science.gov (United States)

    Fabian, Peter; Pantzartzi, Chrysoula N; Kozmikova, Iryna; Kozmik, Zbynek

    2016-03-01

    The midbrain-hindbrain boundary (MHB) is one of the key organizing centers of the vertebrate central nervous system (CNS). Its patterning is governed by a well-described gene regulatory network (GRN) involving several transcription factors, namely, pax, gbx, en, and otx, together with signaling molecules of the Wnt and Fgf families. Here, we describe the onset of these markers in Oryzias latipes (medaka) early brain development in comparison to previously known zebrafish expression patterns. Moreover, we show for the first time that vox, a member of the vent gene family, is expressed in the developing neural tube similarly to CNS markers. Overexpression of vox leads to profound changes in the gene expression patterns of individual components of MHB-specific GRN, most notably of fgf8, a crucial organizer molecule of MHB. Our data suggest that genes from the vent family, in addition to their crucial role in body axis formation, may play a role in regionalization of vertebrate CNS. PMID:26965282

  3. On the role of alloying elements in the formation of serrated grain boundaries in Ni-based alloys

    International Nuclear Information System (INIS)

    Ni-based model alloys were used to study the effect of alloying elements, namely Cr, Mo, C and Zr on the occurrence of grain boundary serration. The model alloys were free of aluminum to exclude precipitation of second-phase γ'. Similarly, the carbon content was very low, when present, to prevent precipitation of carbides. A special heat treatment involving slow cooling was used to promote grain boundary serration. No significant sign of serration was observed for Ni-10Cr-10Mo, Ni-20Cr-10Mo and Ni-10Cr-10Mo-0.05C model alloys. However, substantial serration was observed for Ni-10Cr-10Mo-0.5Zr and Ni-20Cr-0.5Zr model alloys. Serrated grain boundaries were observed in the absence of either γ' or carbides. Zirconium-rich precipitates were recognized at serrated grain boundaries though their involvement in the occurrence of serration was doubtful. A mechanism of grain boundary serration formation is proposed.

  4. On the role of alloying elements in the formation of serrated grain boundaries in Ni-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Terner, Mathieu; Hong, Hyun-Uk; Lee, Je-Hyun [Changwon National Univ. (Korea, Republic of). Dept. of Materials Science and Engineering; Choi, Baig-Gyu [Korea Institute of Materials Science, Changwon (Korea, Republic of). High Temperature Materials Group

    2016-03-15

    Ni-based model alloys were used to study the effect of alloying elements, namely Cr, Mo, C and Zr on the occurrence of grain boundary serration. The model alloys were free of aluminum to exclude precipitation of second-phase γ'. Similarly, the carbon content was very low, when present, to prevent precipitation of carbides. A special heat treatment involving slow cooling was used to promote grain boundary serration. No significant sign of serration was observed for Ni-10Cr-10Mo, Ni-20Cr-10Mo and Ni-10Cr-10Mo-0.05C model alloys. However, substantial serration was observed for Ni-10Cr-10Mo-0.5Zr and Ni-20Cr-0.5Zr model alloys. Serrated grain boundaries were observed in the absence of either γ' or carbides. Zirconium-rich precipitates were recognized at serrated grain boundaries though their involvement in the occurrence of serration was doubtful. A mechanism of grain boundary serration formation is proposed.

  5. Biochemostratigraphy of the Devonian-Carboniferous boundary Global Stratotype Section and Point, Griotte Formation, La Serre, Montagne Noire, France

    OpenAIRE

    Brand, U.; Legrand-Blain, M.; Streel, Maurice

    2004-01-01

    The Griotte Formation and the base of Bed 89 exposed at La Serre, Montagne Noire, France represent the Global Stratotype Section and Point (GSSP) for the Devonian-Carboniferous (D-C) boundary. This study represents the geochemical work on brachiopods and matrix covering the Siphonodella praesulcata to Siphonodella sulcata Zones at the GSSP. Values of Sr-87/Sr-86 of unaltered brachiopods provide the most powerful biochemostratigraphic tool in recognizing and correlating the Devonian-Carbonifer...

  6. Effect of heat treatment on grain boundary precipitate formation in Nimonic PE16

    International Nuclear Information System (INIS)

    Isothermal precipitation curves for small grain boundary precipitates in Nimonic PE16 have been determined experimentally. A theoretical model which describes the growth of grain boundary precipitates is summarised and its application specific to Nimonic PE16 is considered. The fit between experimental and theoretical isothermal precipitation curves and thus the usefulness of the model in predicting improved heat treatments for the alloy is discussed. (author)

  7. Dynamics of formation of low-angle tilt boundaries in metals and alloys at high loading rates

    Science.gov (United States)

    Gutkin, M. Yu.; Rzhavtsev, E. A.

    2015-12-01

    A computer model has been developed in which the process of formation of low-angle tilt boundaries and fragmentation of initial subgrains during shock loading of metals and alloys is clearly demonstrated by the of two-dimensional discrete dislocation-disclination dynamics method. The formation and evolution of such grains proceeds under the action of an external stress and the stress field of grain boundary disclinations distributed on the subgrain boundaries. With the D16 aluminum alloy as an example, three cases of fragmented structures formed in accordance with the initial configuration of the disclination ensemble have been considered for a dipole, quadrupole, and arbitrary octupole of wedge disclinations. It has been shown that, in all these cases, the formation of a stable fragmented structure requires a stress of ~0.5 GPa and time of 10 ns. The main results of computer simulation (the finite form of a fragmented structure, typical level of applied stress, and small fragmentation time) agree well with known experimental results on shock compression of the D16 aluminum alloy.

  8. Fractal pattern formation in thermal grooving at grain boundaries in Ag films on Si(111) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Roy, A. [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Sundaravel, B. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Batabyal, R. [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Dev, B.N., E-mail: msbnd@iacs.res.in [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

    2012-05-31

    Growth of Ag films on Br- and H-passivated Si(111) surfaces and the annealing behaviour have been investigated by Rutherford backscattering spectrometry, scanning electron microscopy and photoemission electron microscopy techniques. Upon annealing the phenomenon of thermal grooving was observed in the Ag films. Depending on the annealing temperature, at an intermediate annealing time Ag depletion (evaporation) from the grain boundaries produces fractal patterns of Ag-depleted regions. Continued annealing eventually produces a percolated network of Ag-depleted regions (thermal grooves) along the grain boundaries and isolated Ag grains appear as the depth of the grooves reaches the substrate. For the fractal structures produced by thermal grooving, the fractal dimension has been estimated to be 1.60 {+-} 0.04. Observation of a fractal pattern in thermal grooving was not hitherto reported. A thorough analysis of the experimental results has been carried out in the context of current theories. These theories are inadequate to describe the experimental results. - Highlights: Black-Right-Pointing-Pointer Thermal grooving in Ag films grown on Si(111) surfaces has been investigated. Black-Right-Pointing-Pointer At appropriate temperatures short annealing shows partly depleted grain boundaries. Black-Right-Pointing-Pointer Depleted grain boundaries reveal a fractal pattern with a fractal dimension of 1.60. Black-Right-Pointing-Pointer Long annealing produces percolated Ag-depleted regions with isolated Ag grains. Black-Right-Pointing-Pointer A thorough analysis shows that current theories are unable to explain the results.

  9. Proteins with GGDEF and EAL domains regulate Pseudomonas putida biofilm formation and dispersal

    DEFF Research Database (Denmark)

    Gjermansen, Morten; Ragas, Paula Cornelia; Tolker-Nielsen, Tim

    2006-01-01

    EAL domains are involved in the regulation of biofilm formation and biofilm dispersion in Pseudomonas putida. Overexpression in P. putida of the Escherichia coli YedQ protein, which contains a GGDEF domain, resulted in increased biofilm formation. Overexpression in P. putida of the E. coli Yhj...... regulating the transition of bacteria between a roaming lifestyle and a sessile biofilm lifestyle....

  10. Analysis of axon tract formation in the zebrafish brain: the role of territories of gene expression and their boundaries.

    Science.gov (United States)

    Wilson, S W; Brennan, C; Macdonald, R; Brand, M; Holder, N

    1997-11-01

    Mutant analysis in the zebrafish is revealing the genes that are expressed in the early neuroepithelium and that regulate factors responsible for the guidance of commissural axons. We review work on the developing zebrafish brain illustrating the way in which territories of regulatory gene expression influence the formation and positioning of axon pathways. PMID:9321679

  11. Estimation of the ozone formation rate in the atmospheric boundary layer over a background region of Western Siberia

    Science.gov (United States)

    Antokhin, P. N.; Antokhina, O. Y.; Belan, B. D.

    2015-11-01

    The ozone formation rate in the atmospheric boundary layer (ABL) and the ozone inflow from the free atmosphere have been studied experimentally. The obtained estimates are based on the data of airborne sounding carried out over a background region of Western Siberia. As a result, it is obtained that the rate of ozone inflow from the upper atmospheric layers is only 20% of the rate of photochemical formation of ozone inside ABL. The vertical profiles of ozone flows in ABL have been additionally calculated based on the k-theory with the approach proposed by Troen and Mahrt. It has been shown in the calculations that the maximum of the ozone concentration in ABL is formed due to photochemical reactions from precursor gases.

  12. FOCUS ON FORMATIVE FEEDBACKCOMMUNICATION AND SELF-REGULATED LEARNING – A STUDY IN COMPULSORY SCHOOLS

    DEFF Research Database (Denmark)

    Kirkegaard, Preben Olund

    2016-01-01

    This study addresses the conceptual challenge of providing students in compulsory schools with good quality formative feedback to enhance self-regulated learning in social interactions. Resent educational research indicates that social communicative interactions in the classroom, with a focus on...... formative feedback, hold the potential to enhance students learning. Self-regulated learning is highly pertinent and can be seen as one of the most import skills for the 21st century learner. We argue that formative feedbackcommunication in interactions is crucial for students to develop self......-regulating skills and that feedback is not only something the teacher gives to the student. We refer to this as formative Feedbackcommunication. As a basis for exploring identifying and discussing relevant aspects of formative Feedbackcommunication to enhance student self-regulating learning skills we analyze...

  13. Evolution of Prolate Molecular Clouds at Hii Boundaries: II. Formation of BRCs of asymmetrical morphology

    CERN Document Server

    Kinnear, T M; White, G J; Sugitani, K; Goodwin, S

    2015-01-01

    A systematic investigation on the evolution of a prolate cloud at an Hii boundary is conducted using Smoothed Particle Hydrodynamics (SPH) in order to understand the mechanism for a variety of irregular morphological structures found at the boundaries of various Hii regions. The prolate molecular clouds in this investigation are set with their semi-major axes at inclinations between 0 and 90 degrees to a plane parallel ionizing radiation flux. A set of 4 parameters, the number density n, the ratio of major to minor axis gamma, the inclination angle phi and the incident flux F_EUV, are used to define the initial state of the simulated clouds. The dependence of the evolution of a prolate cloud under Radiation Driven Implosion (RDI) on each of the four parameters is investigated. It is found that: i) in addition to the well studied standard type A, B or C Bright Rimmed Clouds (BRCs), many other types such as asymmetrical BRCs, filamentary structures and irregular horse-head structures could also be developed at ...

  14. Prerequisites of Formation of the Mechanism of State Regulation of the System of Commercial Insurance

    Directory of Open Access Journals (Sweden)

    Kuzhelyev Mykhaylo O.

    2014-01-01

    Full Text Available The article analyses establishment of the domestic system of commercial insurance with consideration of genesis of mechanisms of its regulation. It shows that the basis of the state regulation of insurance should be formed by the model of economic and historical process of establishment and development of commercial insurance, allowing to reveal the role of the state in formation of efficient instruments of administration and development of this system. The article establishes that evolution of formation of the state mechanism of administration is a reaction to imperfection of mechanisms of self-regulation of the system of commercial insurance. It argues that the national model of state regulation has specific features of the continental model, which is manifested in the applied forms of regulation. The author tracked formation of the modern mechanism of state regulation of the system of commercial insurance in genesis, which allowed trustworthy establishment of its specific features and prospects of development.

  15. Feedback Regulated Star Formation: From Star Clusters to Galaxies

    CERN Document Server

    Dib, Sami

    2011-01-01

    This paper summarises results from semi-analytical modelling of star formation in protocluster clumps of different metallicities. In this model, gravitationally bound cores form uniformly in the clump following a prescribed core formation efficiency per unit time. After a contraction timescale which is equal to a few times their free-fall times, the cores collapse into stars and populate the IMF. Feedback from the newly formed OB stars is taken into account in the form of stellar winds. When the ratio of the effective wind energy of the winds to the gravitational energy of the system reaches unity, gas is removed from the clump and core and star formation are quenched. The power of the radiation driven winds has a strong dependence on metallicity and increases with increasing metallicity. Thus, winds from stars in the high metallicity models lead to a rapid evacuation of the gas from the protocluster clump and to a reduced star formation efficiency, SFE_{exp}, as compared to their low metallicity counterparts...

  16. Formation of Cavities at and Away from Grain Boundaries during 600 MeV Proton Irradiation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Green, W. V.; Green, S. L.

    1982-01-01

    High-purity aluminium (99.9999%) was irradiated with 600 MeV protons at the Swiss Institute for Nuclear Research (SIN) with a damage rate of 3,5 x 10^-6 dpa/s. Irradiation with 600 MeV protons produces helium, hydrogen, and other impurities through mutational reactions. The irradiation experiments...... were carried out at 120 degree C (0,42*Tm where Tm is the melting temperature in K). Transmission electron microscopy on specimens irradiated to 0.2 and 0.6 dpa has shown the presence of (a) cavity-denuded zones (CDZ) along grain boundaries, (b) cavity-containing zones (CCZ) adjacent to the CDZ and (c...

  17. Regularities in the formation of dislocation networks on the boundary of bonded Si(001) wafers

    International Nuclear Information System (INIS)

    The dislocation networks in structures with hydrophilically bonded Si (001) wafers are investigated by transmission electron microscopy. Networks with differing geometry and type of dominant dislocations are observed. One type of networks, which is typical of bonded structures, is formed on the basis of a square network of screw dislocations and contains a system of unidirectional 60° zigzag-shaped dislocations. It is established that such dislocation networks are flat in structures with an azimuthal misorientation of wafers exceeding 2°, whereas they are three-dimensional at smaller misorientation angles. A unique network of another type is formed only by 60° dislocations, the majority of which are extended along one direction, which does not coincide with the 〈110〉 directions in the boundary plane and has a number of specific features, the explanation of which is impossible within the framework of conventional representations.

  18. Marine boundary layer cloud regimes and POC formation in an LES coupled to a bulk aerosol scheme

    Directory of Open Access Journals (Sweden)

    A. H. Berner

    2013-07-01

    Full Text Available A large-eddy simulation (LES coupled to a new bulk aerosol scheme is used to study long-lived regimes of aerosol-boundary layer cloud-precipitation interaction and the development of pockets of open cells (POCs in subtropical stratocumulus cloud layers. The aerosol scheme prognoses mass and number concentration of a single log-normal accumulation mode with surface and entrainment sources, evolving subject to processing of activated aerosol and scavenging of dry aerosol by cloud and rain. The LES with the aerosol scheme is applied to a range of steadily-forced simulations idealized from a well-observed POC case. The long-term system evolution is explored with extended two-dimensional simulations of up to 20 days, mostly with diurnally-averaged insolation. One three-dimensional two-day simulation confirms the initial development of the corresponding two-dimensional case. With weak mean subsidence, an initially aerosol-rich mixed layer deepens, the capping stratocumulus cloud slowly thickens and increasingly depletes aerosol via precipitation accretion, then the boundary layer transitions within a few hours into an open-cell regime with scattered precipitating cumuli, in which entrainment is much weaker. The inversion slowly collapses for several days until the cumulus clouds are too shallow to efficiently precipitate. Inversion cloud then reforms and radiatively drives renewed entrainment, allowing the boundary layer to deepen and become more aerosol-rich, until the stratocumulus layer thickens enough to undergo another cycle of open-cell formation. If mean subsidence is stronger, the stratocumulus never thickens enough to initiate drizzle and settles into a steady state. With lower initial aerosol concentrations, this system quickly transitions into open cells, collapses, and redevelops into a different steady state with a shallow, optically thin cloud layer. In these steady states, interstitial scavenging by cloud droplets is the main sink of

  19. The impact of boundary conditions on CO2 capacity estimation in aquifers

    OpenAIRE

    Smith, D.J.; Bentham, M.; Holloway, S.; Noy, D.J.; Chadwick, R.A.

    2010-01-01

    The boundary conditions of an aquifer determine the extent to which fluids (including formation water and CO2) and pressure can be transferred into adjacent geological formations, either laterally or vertically. Aquifer boundaries can be faults, lithological boundaries, formation pinch-outs, salt walls, or outcrop. In many cases compliance with regulations preventing CO2 storage influencing areas outside artificial boundaries defined by non-geological criteria (international bound...

  20. HDAC2 Negatively Regulates Memory Formation and Synaptic Plasticity

    OpenAIRE

    Guan, Ji-Song; Giacometti, Emanuela; Dannenberg, Jan-Hermen; Joseph, Nadine; Gao, Jun; DePinho, Ronald A.; Jaenisch, Rudolf; Tsai, Li-Huei; Haggarty, Stephen John; Nieland, Thomas; Ying ZHOU; Wang, Xinyu; Mazitschek, Ralph; Bradner, James Elliott

    2012-01-01

    Chromatin modifications, especially histone-tail acetylation, have been implicated in memory formation. Increased histone-tail acetylation induced by inhibitors of histone deacetylases (HDACis) facilitates learning and memory in wild-type mice as well as in mouse models of neurodegeneration. Harnessing the therapeutic potential of HDACis requires knowledge of the specific HDAC family member(s) linked to cognitive enhancement. Here we show that neuron-specific overexpression of HDAC2, but not ...

  1. Structural constraints regulating triple helix formation by A-tracts.

    Science.gov (United States)

    Sen, A; Gräslund, A

    2000-12-15

    The study concerns the propensity of triple helix formation by different DNA oligonucleotides containing long A-tracts with and without flanking GxC base pairs in order to probe the role of length of the A-tract and the flanking sequences. From nuclear magnetic resonance (NMR) studies of imino proton spectra and circular dichroism (CD) spectroscopy of samples composed of potential triplex forming strand sequences in correct stoichiometries, we have concluded that 8-mer A-tracts flanked by GxC base pairs exert significant steric hindrance to triple helix formation. When as much as 50 mM Mg2+ was added, no triple helix formation was observed in these samples. In contrast, open-ended 8-mer A-tracts formed triplex with the corresponding two T8 strands under relatively mild ionic conditions (100 mM Na+). Moreover, the shorter the length of the A-tract, the less is the hindrance to form a triple helix. PMID:11152277

  2. Environmental regulation of cloud and star formation in galactic bars

    CERN Document Server

    Renaud, F; Emsellem, E; Agertz, O; Athanassoula, E; Combes, F; Elmegreen, B; Kraljic, K; Motte, F; Teyssier, R

    2015-01-01

    The strong time-dependence of the dynamics of galactic bars yields a complex and rapidly evolving distribution of dense gas and star forming regions. Although bars mainly host regions void of any star formation activity, their extremities can gather the physical conditions for the formation of molecular complexes and mini-starbursts. Using a sub-parsec resolution hydrodynamical simulation of a Milky Way-like galaxy, we probe these conditions to explore how and where bar (hydro-)dynamics favours the formation or destruction of molecular clouds and stars. The interplay between the kpc-scale dynamics (gas flows, shear) and the parsec-scale (turbulence) is key to this problem. We find a strong dichotomy between the leading and trailing sides of the bar, in term of cloud fragmentation and in the age distribution of the young stars. After orbiting along the bar edge, these young structures slow down at the extremities of the bar, where orbital crowding increases the probability of cloud-cloud collision. We find tha...

  3. CD13/APN regulates endothelial invasion and filopodia formation

    OpenAIRE

    Petrovic, Nenad; Schacke, Wolfgang; Gahagan, J. Reed; O'Conor, Catherine A.; Winnicka, Beata; Conway, Rebecca E.; Mina-Osorio, Paola; Shapiro, Linda H.

    2007-01-01

    CD13/aminopeptidase N is a transmembrane peptidase that is induced in the vasculature of solid tumors and is a potent angiogenic regulator. Here, we demonstrate that CD13 controls endothelial cell invasion in response to the serum peptide bradykinin by facilitating signal transduction at the level of the plasma membrane. Inhibition of CD13 abrogates bradykinin B2 receptor internalization, leading to the attenuation of downstream events such as bradykinin-induced activation of Cdc42 and filopo...

  4. Cooperative action of the paralogous maize lateral organ boundaries (LOB) domain proteins RTCS and RTCL in shoot-borne root formation.

    Science.gov (United States)

    Xu, Changzheng; Tai, Huanhuan; Saleem, Muhammad; Ludwig, Yvonne; Majer, Christine; Berendzen, Kenneth W; Nagel, Kerstin A; Wojciechowski, Tobias; Meeley, Robert B; Taramino, Graziana; Hochholdinger, Frank

    2015-09-01

    The paralogous maize (Zea mays) LBD (Lateral Organ Boundaries Domain) genes rtcs (rootless concerning crown and seminal roots) and rtcl (rtcs-like) emerged from an ancient whole-genome duplication. RTCS is a key regulator of crown root initiation. The diversity of expression, molecular interaction and phenotype of rtcs and rtcl were investigated. The rtcs and rtcl genes display highly correlated spatio-temporal expression patterns in roots, despite the significantly higher expression of rtcs. Both RTCS and RTCL proteins bind to LBD downstream promoters and act as transcription factors. In line with its auxin inducibility and binding to auxin response elements of rtcs and rtcl promoters, ARF34 (AUXIN RESPONSE FACTOR 34) acts as transcriptional activator. Yeast two-hybrid screening combined with bimolecular fluorescence complementation (BiFC) experiments revealed conserved and unique interaction partners of RTCS and RTCL. The rtcl mutation leads to defective shoot-borne root elongation early in development. Cooperative action of RTCS and RTCL during shoot-borne root formation was demonstrated by rtcs-dependent repression of rtcl transcription in coleoptilar nodes. Although RTCS is instrumental in shoot-borne root initiation, RTCL controls shoot-borne root elongation early in development. Their conserved role in auxin signaling, but diverse function in shoot-borne root formation, is underscored by their conserved and unique interaction partners. PMID:25902765

  5. SarA is a negative regulator of Staphylococcus epidermidis biofilm formation

    DEFF Research Database (Denmark)

    Martin, Christer; Heinze, C.; Busch, M.; Franke, G.; Hentschke, M.; Dühring, Sara Bayard; Buettner, H.; Kotasinska, M.; Wischnewski, V.; Buck, F.; Molin, Søren; Otto, Michael; Rohde, Henning

    2012-01-01

    the existence of superimposed regulatory systems suppressing a multi-cellular biofilm life style in vitro. Transposon mutagenesis of clinical significant but biofilm-negative S. epidermidis 1585 was used to isolate a biofilm positive mutant carrying a Tn917 insertion in sarA,chief regulator of...... contributed to biofilm formation in mutant 1585ΔsarA. Increased eDNA amounts indirectly resulted from up-regulation of metalloprotease SepA, leading to boosted processing of major autolysin AtlE, in turn inducing augmented autolysis and release of chromosomal DNA. Hence, this study identifies sarA as a...... negative regulator of Embp- and eDNA dependent biofilm formation. Given the importance of SarA as a positive regulator of polysaccharide mediated cell aggregation, the regulator enables S. epidermidis to switch between mechanisms of biofilm formation, ensuring S. epidermidis adaptation to hostile...

  6. Line tension at lipid phase boundaries regulates formation of membrane vesicles in living cells

    DEFF Research Database (Denmark)

    Vind-Kezunovic, Dina; Helix Nielsen, Claus; Wojewodzka, Urszula; Gniadecki, Robert

    2008-01-01

    -labeled cholera toxin B subunit which labels ganglioside GM(1) enriched plasma membrane rafts. Cholesterol depletion with methyl-beta-cyclodextrin enhanced DiI vesiculation, GM(1)/DiI domain separation and was accompanied by a detachment of the subcortical cytoskeleton from the plasma membrane. Based on these...

  7. Hrs regulates multivesicular body formation via ESCRT recruitment to endosomes

    OpenAIRE

    Bache, Kristi G.; Brech, Andreas; Mehlum, Anja; Stenmark, Harald

    2003-01-01

    Hrs and the endosomal sorting complexes required for transport, ESCRT-I, -II, and -III, are involved in the endosomal sorting of membrane proteins into multivesicular bodies and lysosomes or vacuoles. The ESCRT complexes are also required for formation of intraluminal endosomal vesicles and for budding of certain enveloped RNA viruses such as HIV. Here, we show that Hrs binds to the ESCRT-I subunit Tsg101 via a PSAP motif that is conserved in Tsg101-binding viral proteins. Depletion of Hrs ca...

  8. Links Between the Deep Western Boundary Current, Labrador Sea Water Formation and Export, and the Meridional Overturning Circulation

    Science.gov (United States)

    Myers, Paul G.; Kulan, Nilgun

    2010-05-01

    Based on an isopyncal analysis of historical data, 3-year overlapping triad fields of objectively analysed temperature and salinity are produced for the Labrador Sea, covering 1949-1999. These fields are then used to spectrally nudge an eddy-permitting ocean general circulation model of the sub-polar gyre, otherwise forced by inter annually varying surface forcing based upon the Coordinated Ocean Reference Experiment (CORE). High frequency output from the reanalysis is used to examine Labrador Sea Water formation and its export. A number of different apprpoaches are used to estimate Labrador Sea Water formation, including an instanteous kinematic approach to calculate the annual rate of water mass subduction at a given density range. Historical transports are computed along sections at 53 and 56N for several different water masses for comparison with recent observations, showing a decline in the stength of the deep western boundary current with time. The variability of the strength of the meridional overturning circulation (MOC) from the reanalysis is also examined in both depth and density space. Linkages between MOC variability and water mass formation variability is considered.

  9. Vitamin C: A Novel Regulator of Neutrophil Extracellular Trap Formation

    Directory of Open Access Journals (Sweden)

    Ramesh Natarajan

    2013-08-01

    Full Text Available Introduction: Neutrophil extracellular trap (NET formation was recently identified as a novel mechanism to kill pathogens. However, excessive NET formation in sepsis can injure host tissues. We have recently shown that parenteral vitamin C (VitC is protective in sepsis. Whether VitC alters NETosis is unknown. Methods: We used Gulo−/− mice as they lack the ability to synthesize VitC. Sepsis was induced by intraperitoneal infusion of a fecal stem solution (abdominal peritonitis, FIP. Some VitC deficient Gulo−/− mice received an infusion of ascorbic acid (AscA, 200 mg/kg 30 min after induction of FIP. NETosis was assessed histologically and by quantification for circulating free DNA (cf-DNA in serum. Autophagy, histone citrullination, endoplasmic reticulum (ER stress, NFκB activation and apoptosis were investigated in peritoneal PMNs. Results: Sepsis produced significant NETs in the lungs of VitC deficient Gulo−/− mice and increased circulating cf-DNA. This was attenuated in the VitC sufficient Gulo−/− mice and in VitC deficient Gulo−/− mice infused with AscA. Polymorphonuclear neutrophils (PMNs from VitC deficient Gulo−/− mice demonstrated increased activation of ER stress, autophagy, histone citrullination, and NFκB activation, while apoptosis was inhibited. VitC also significantly attenuated PMA induced NETosis in PMNs from healthy human volunteers.

  10. Feedback-regulated Super Massive Black Hole Seed Formation

    CERN Document Server

    Dijkstra, Mark; Mesinger, Andrei

    2014-01-01

    The nature of the seeds of high-redshift supermassive black holes (SMBHs) is a key question in cosmology. Direct collapse black holes (DCBH) that form in pristine, atomic-line cooling halos, illuminated by a Lyman-Werner (LW) UV flux exceeding a critical threshold J_crit, represent an attractive possibility. We investigate when and where these conditions are met during cosmic evolution. For the LW intensity, J_LW, we account for departures from the background value in close proximity to star forming galaxies. For the pristine halo fraction, we account for both (i) supernova driven outflows, and (ii) the inherent pollution from progenitor halos. We estimate the abundance of DCBH formation sites, n_DCBH(z), and find that it increases with cosmic time from n_DCBH(z=20) ~ 1e-12 -1e-7 cMpc^-3 to n_DCBH(z=10) ~ 1e-10 - 1e-5 cMpc^-3. Our analysis shows the possible importance of galactic winds, which can suppress the predicted n_DCBH by several orders of magnitude, and cause DCBH formation to preferentially occur ar...

  11. Environment and self-regulation in galaxy formation

    CERN Document Server

    Thomas, Daniel; Schawinski, Kevin; Sarzi, Marc; Silk, Joseph

    2009-01-01

    The environment is known to affect the formation and evolution of galaxies considerably best visible through the well-known morphology-density relationship. In this paper we study the effect of environment on the evolution of early-type galaxies by analysing the stellar population properties of 3,360 galaxies morphologically selected by visual inspection from the SDSS in the redshift range 0.05formation through their emissio...

  12. Pattern formation in a gene network model with boundary shape dependence

    Science.gov (United States)

    Diambra, Luis; da Fontoura Costa, Luciano

    2006-03-01

    A fundamental task in developmental biology is to identify the mechanisms which drive morphogenesis. Traditionally pattern formation have been modeled mainly using Turing-type mechanisms, where complex patterns arise by symmetry breaking. However, there is a growing experimental evidence that the influence of signals derived from surrounding tissues can contribute to the patterning processes. In this paper, we show that the interplay between the shape of surrounding tissues and a hierarchically organized gene regulatory network can be able to induce stable complex patterns. The rise of these patterns depends strongly on the shape of the surrounding tissues.

  13. High-gain adaptive regulator for a string equation with uncertain harmonic disturbance under boundary output feedback control

    Institute of Scientific and Technical Information of China (English)

    Baozhu GUO; Wei GUO

    2003-01-01

    This paper considers the boundary stabilization and parameter estimation of a one-dimensional wave equation in the case when one end is fixed and control and harmonic disturbance with uncertain amplitude are input at another end. A high-gain adaptive regulator is designed in terms of measured collocated end velocity. The existence and uniqueness of the classical solution of the closed-loop system is proven. It is shown that the state of the system approaches the standstill as time goes to infitv and meanwhile, the estimated parameter converges to the unknown parameter.

  14. Formation of magnetic discontinuities through superposition of force-free magnetic fields: Periodic boundaries

    International Nuclear Information System (INIS)

    In ideal magnetohydrodynamics characterized by an infinite electrical conductivity, the magnetic flux across an arbitrary fluid surface is conserved in time. The magnetofluid then can be partitioned into contiguous subvolumes of fluid, each of which entraps its own subsystem of magnetic flux. During dynamical evolution of the magnetofluid, these subvolumes press into each other; and in the process, two such subvolumes may come into direct contact while ejecting a third interstitial subvolume. Depending on the orientations of magnetic fields of the two interacting subvolumes, the magnetic field at the common surface of interaction may become discontinuous and a current sheet is formed there. This process of current sheet formation and their subsequent decay is believed to be a plausible mechanism for coronal heating and may also be responsible for various eruptive phenomena at the solar corona. In this work, we explore this theoretical concept through numerical simulations of a viscous, incompressible magnetofluid characterized by infinite electrical conductivity. In particular, we show that if the initial magnetic field is prescribed by superposition of two linear force-free fields with different torsion coefficients, then formation of current sheets are numerically realizable in the neighborhood of magnetic nulls

  15. Experimental study of boundary layers formation by thin film colorimetric interferometry

    Institute of Scientific and Technical Information of China (English)

    MartinHartl; IvanKrupka; MiroslavLiska

    2001-01-01

    Thin film colorimetric interferometry was applied to the preliminary study of boundarylayers formation for a several liquids of known molecular structure that have been previously stud-ied by the force balance method. This technique intended for the study of very thin lubrication filmsdown to a few nanometers in a point contact between a steel ball and a transparent disk combinespowerful film thickness mapping capabilities with high accuracy. Central and minimum film thick-ness as well as film shape in the dependence on rolling speed was studied for hexadecane, oc-tamethylcyclotetrasiloxane (OMCTS) and n-tetradecane. Results are compared with data obtainedfrom surface force apparatus measurements. OMCTS and n-tetradecane were found to formboundary films that result in a considerable enhancement in film thickness at slow speeds.

  16. From dynamic expression patterns to boundary formation in the presomitic mesoderm.

    Directory of Open Access Journals (Sweden)

    Hendrik B Tiedemann

    Full Text Available The segmentation of the vertebrate body is laid down during early embryogenesis. The formation of signaling gradients, the periodic expression of genes of the Notch-, Fgf- and Wnt-pathways and their interplay in the unsegmented presomitic mesoderm (PSM precedes the rhythmic budding of nascent somites at its anterior end, which later develops into epithelialized structures, the somites. Although many in silico models describing partial aspects of somitogenesis already exist, simulations of a complete causal chain from gene expression in the growth zone via the interaction of multiple cells to segmentation are rare. Here, we present an enhanced gene regulatory network (GRN for mice in a simulation program that models the growing PSM by many virtual cells and integrates WNT3A and FGF8 gradient formation, periodic gene expression and Delta/Notch signaling. Assuming Hes7 as core of the somitogenesis clock and LFNG as modulator, we postulate a negative feedback of HES7 on Dll1 leading to an oscillating Dll1 expression as seen in vivo. Furthermore, we are able to simulate the experimentally observed wave of activated NOTCH (NICD as a result of the interactions in the GRN. We esteem our model as robust for a wide range of parameter values with the Hes7 mRNA and protein decays exerting a strong influence on the core oscillator. Moreover, our model predicts interference between Hes1 and HES7 oscillators when their intrinsic frequencies differ. In conclusion, we have built a comprehensive model of somitogenesis with HES7 as core oscillator that is able to reproduce many experimentally observed data in mice.

  17. 77 FR 23425 - Revisions of Boundaries, Regulations and Zoning Scheme for Florida Keys National Marine Sanctuary...

    Science.gov (United States)

    2012-04-19

    ... operations and projects, including education and outreach, research and science, regulations and enforcement.... Pursuant to 36 CFR 800.16(1)(1), historic properties includes: ``any prehistoric or historic district,...

  18. Western boundary currents regulated by interaction between ocean eddies and the atmosphere

    Science.gov (United States)

    Ma, Xiaohui; Jing, Zhao; Chang, Ping; Liu, Xue; Montuoro, Raffaele; Small, R. Justin; Bryan, Frank O.; Greatbatch, Richard J.; Brandt, Peter; Wu, Dexing; Lin, Xiaopei; Wu, Lixin

    2016-07-01

    Current climate models systematically underestimate the strength of oceanic fronts associated with strong western boundary currents, such as the Kuroshio and Gulf Stream Extensions, and have difficulty simulating their positions at the mid-latitude ocean’s western boundaries. Even with an enhanced grid resolution to resolve ocean mesoscale eddies—energetic circulations with horizontal scales of about a hundred kilometres that strongly interact with the fronts and currents—the bias problem can still persist; to improve climate models we need a better understanding of the dynamics governing these oceanic frontal regimes. Yet prevailing theories about the western boundary fronts are based on ocean internal dynamics without taking into consideration the intense air–sea feedbacks in these oceanic frontal regions. Here, by focusing on the Kuroshio Extension Jet east of Japan as the direct continuation of the Kuroshio, we show that feedback between ocean mesoscale eddies and the atmosphere (OME-A) is fundamental to the dynamics and control of these energetic currents. Suppressing OME-A feedback in eddy-resolving coupled climate model simulations results in a 20–40 per cent weakening in the Kuroshio Extension Jet. This is because OME-A feedback dominates eddy potential energy destruction, which dissipates more than 70 per cent of the eddy potential energy extracted from the Kuroshio Extension Jet. The absence of OME-A feedback inevitably leads to a reduction in eddy potential energy production in order to balance the energy budget, which results in a weakened mean current. The finding has important implications for improving climate models’ representation of major oceanic fronts, which are essential components in the simulation and prediction of extratropical storms and other extreme events, as well as in the projection of the effect on these events of climate change.

  19. Interchange Reconnection and Slow Solar Wind Formation at the boundaries of open field regions in the Solar Corona

    Science.gov (United States)

    Rappazzo, A. F.; Matthaeus, W. H.; Ruffolo, D. J.; Servidio, S.; Velli, M.

    2014-12-01

    Interchange reconnection, i.e., magnetic reconnection at the interface between open and closed corona, is thought to contribute to the formation of the slowsolar wind, since it can inject the hotter and denserplasma from closed regions into the heliosphere,and account for the different slow wind composition (thatis similar to the plasma of closed regions) respectto the fast wind. The interchange process has mostly been investigatedfor magnetic field lines with opposite polarity and null points, either for the case of counterdirected loops (e.g., Fisk et al. 1999, Fisk and Schwadron 2001), or in correspondence of null points at the apex of streamers or pseudo-streamers (e.g., Wang et al. 1998,Edmondson et al. 2010, Del Zanna et al. 2011).Magnetic reconnection can certainly occur in these configurations,but they occupy a very small volume of the corona. On the other hand component magnetic reconnection at the boundarybetween coronal holes and streamers or pseudo-streamers hasreceived less attention, even though it can occur aroundthe entire extension of such boundaries. Magnetic reconnection is at the basis of Parker'snanoflare scenario for the heating of coronal loops.Modeling such regions in cartesian geometry with a strongguide field, it has been shown numerically that photosphericmotions induce a magnetic fieldcomponent orthogonal to the strong axial field characterizedby the presence of many current sheets, where the field lines are locally oppositely directed, and can reconnect (Einaudi et al. 1996; Dmitruk and Gomez 1997).The reconnection of the orthogonal component of the magneticfield leads to a change of connectivity of the field linesof the total magnetic field that connect one photospheric boundaryto the other. We have shown that a similar interchange mechanismcan operate in and around the boundaries between open and closedregions inducing a continual stochastic rearrangement of connectivityeverywhere along the open-closed boundary (Rappazzo et al. 2012

  20. Magnetically self-regulated formation of early protoplanetary discs

    CERN Document Server

    Hennebelle, Patrick; Chabrier, Gilles; Marchand, Pierre

    2016-01-01

    The formation of protoplanetary discs during the collapse of molecular dense cores is significantly influenced by angular momentum transport, notably by the magnetic torque. In turn, the evolution of the magnetic field is determined by dynamical processes and non-ideal MHD effects such as ambipolar diffusion. Considering simple relations between various timescales characteristic of the magnetized collapse, we derive an expression for the early disc radius, $ r \\simeq 18 \\, {\\rm AU} \\, \\left({\\eta_{\\rm AD} / 0.1 \\, {\\rm s}} \\right)^{2/9} \\left({B_z / 0.1\\, {\\rm G}} \\right) ^{-4/9} \\left({M / 0.1 \\msol} \\right) ^{1/3},$ where $M$ is the total disc plus protostar mass, $\\eta_\\mathrm{AD}$ is the ambipolar diffusion coefficient and $B_z$ is the magnetic field in the inner part of the core. This is about significantly smaller than the discs that would form if angular momentum was conserved. The analytical predictions are confronted against a large sample of 3D, non-ideal MHD collapse calculations covering variation...

  1. Surface microcracks signal osteoblasts to regulate alignment and bone formation.

    Science.gov (United States)

    Shu, Yutian; Baumann, Melissa J; Case, Eldon D; Irwin, Regina K; Meyer, Sarah E; Pearson, Craig S; McCabe, Laura R

    2014-11-01

    Microcracks are present in bone and can result from fatigue damage due to repeated, cyclically applied stresses. From a mechanical point, microcracks can dissipate strain energy at the advancing tip of a crack to improve overall bone toughness. Physiologically, microcracks are thought to trigger bone remodeling. Here, we examine the effect of microcracks specifically on osteoblasts, which are bone-forming cells, by comparing cell responses on microcracked versus non-microcracked hydroxyapatite (HA) specimens. Osteoblast attachment was found to be greater on microcracked HA specimens (pmicrocracks on HA. Cells also displayed a preferential attachment that was 75 to 90 μm away from the microcrack indent. After 21 days of culture, osteoblast maturation was notably enhanced on the HA with microcracks, as indicated by increased alkaline phosphatase activity and gene expression. Furthermore, examination of bone deposition by confocal laser scanning microscopy indicated preferential mineralization at microcrack indentation sites. Dissolution studies indicate that the microcracks increase calcium release, which could contribute to osteoblast responses. Our findings suggest that microcracks signal osteoblast attachment and bone formation/healing. PMID:25280696

  2. Cholesterol Regulates Syntaxin 6 Trafficking at trans-Golgi Network Endosomal Boundaries

    Directory of Open Access Journals (Sweden)

    Meritxell Reverter

    2014-05-01

    Full Text Available Inhibition of cholesterol export from late endosomes causes cellular cholesterol imbalance, including cholesterol depletion in the trans-Golgi network (TGN. Here, using Chinese hamster ovary (CHO Niemann-Pick type C1 (NPC1 mutant cell lines and human NPC1 mutant fibroblasts, we show that altered cholesterol levels at the TGN/endosome boundaries trigger Syntaxin 6 (Stx6 accumulation into VAMP3, transferrin, and Rab11-positive recycling endosomes (REs. This increases Stx6/VAMP3 interaction and interferes with the recycling of αVβ3 and α5β1 integrins and cell migration, possibly in a Stx6-dependent manner. In NPC1 mutant cells, restoration of cholesterol levels in the TGN, but not inhibition of VAMP3, restores the steady-state localization of Stx6 in the TGN. Furthermore, elevation of RE cholesterol is associated with increased amounts of Stx6 in RE. Hence, the fine-tuning of cholesterol levels at the TGN-RE boundaries together with a subset of cholesterol-sensitive SNARE proteins may play a regulatory role in cell migration and invasion.

  3. Influence of boundary effects on electron beam dose distribution formation in multilayer targets

    International Nuclear Information System (INIS)

    Computational dosimetry play a significant role in an industrial radiation processing at dose measurements in the product irradiated with electron beams (EB), X-ray and gamma ray from radionuclide sources. Accurate and validated programs for absorbed dose calculations are required for computational dosimetry. The program ModeStEB (modelling of EB processing in a three-dimensional (3D) multilayer flat targets) was designed specially for simulation and optimization of industrial radiation processing, calculation of the 3D absorbed dose distribution within multilayer packages. The package is irradiated with scanned EB on an industrial radiation facility that is based on the pulsed or continuous type of electron accelerators in the electron energy range from 0.1 to 25 MeV. Simulation of EB dose distributions in the multilayer targets was accomplished using the Monte Carlo (MC) method. Experimental verification of MC simulation prediction for EB dose distribution formation in a stack of plates interleaved with polyvinylchloride (PVC) dosimetric films (DF), within a packing box, and irradiated with a scanned 10 MeV EB on a moving conveyer is discussed. (authors)

  4. Collaborative jurisdiction in the regulation of electric utilities: A new look at jurisdictional boundaries

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-12-31

    This conference is one of several activities initiated by FERC, DOE and NARUC to improve the dialogue between Federal and State regulators and policymakers. I am pleased to be here to participate in this conference and to address, with you, electricity issues of truly national significance. I would like to commend Ashley Brown and the NARUC Electricity Committee for its foresight in devising a conference on these issues at this critical juncture in the regulation of the electric utility industry. I also would like to commend Chairman Allday and the FERC for their efforts to improve communication between Federal and State electricity regulators; both through FERC`s Public Conference on Electricity Issues that was held last June, and through the FERC/NARUC workshops that are scheduled to follow this conference. These collaborative efforts are important and necessary steps in addressing successfully the many issues facing the electric utility industry those who regulate it, and those who depend upon it - in other words, about everyone.

  5. Transmembrane Agrin Regulates Dendritic Filopodia and Synapse Formation in Mature Hippocampal Neuron Cultures

    OpenAIRE

    McCroskery, Seumas; Bailey, Allison; Lin, Lin; Daniels, Mathew P.

    2009-01-01

    The transmembrane isoform of agrin (Tm-agrin) is the predominant form expressed in the brain but its putative roles in brain development are not well understood. Recent reports have implicated Tm-agrin in the formation and stabilization of filopodia on neurites of immature central and peripheral neurons in culture. In maturing central neurons, dendritic filopodia are believed to facilitate synapse formation. In the present study we have investigated the role of Tm-agrin in regulation of dendr...

  6. tal1 regulates the formation of intercellular junctions and the maintenance of identity in the endocardium

    OpenAIRE

    Schumacher, Jennifer A.; Bloomekatz, Joshua; Garavito-Aguilar, Zayra V.; Yelon, Deborah

    2013-01-01

    The endocardium forms the inner lining of the heart tube, where it enables blood flow and also interacts with the myocardium during the formation of valves and trabeculae. Although a number of studies have identified regulators of the morphogenesis of the myocardium, relatively little is known about the molecules that control endocardial morphogenesis. Prior work has implicated the bHLH transcription factor Tal1 in endocardial tube formation: in zebrafish embryos lacking Tal1, endocardial cel...

  7. Hypoxic Adaptation by Efg1 Regulates Biofilm Formation by Candida albicans▿

    OpenAIRE

    Stichternoth, Catrin; Ernst, Joachim F.

    2009-01-01

    Hypoxia is encountered frequently by Candida albicans during systemic infection of the human host. We tested if hypoxia allows biofilm formation by C. albicans, which is a major cause of perseverance and antifungal resistance in C. albicans infections. Using an in vitro biofilm system, we unexpectedly discovered that several positive regulators of biofilm formation during normoxia, including Tec1, Ace2, Czf1, Och1, and Als3, had little or no influence on biofilm development during hypoxia, ir...

  8. Biofilm Formation by Bacillus cereus Is Influenced by PlcR, a Pleiotropic Regulator

    OpenAIRE

    Hsueh, Yi-Huang; Somers, Eileen B.; Lereclus, Didier; Wong, Amy C. Lee

    2006-01-01

    The ΔplcR mutant of Bacillus cereus strain ATCC 14579 developed significantly more biofilm than the wild type and produced increased amounts of biosurfactant. Biosurfactant production is required for biofilm formation and may be directly or indirectly repressed by PlcR, a pleiotropic regulator. Coating polystyrene plates with surfactin, a biosurfactant from Bacillus subtilis, rescued the deficiency in biofilm formation by the wild type.

  9. Techniques for jar formation of valve-regulated lead-acid batteries

    Science.gov (United States)

    Weighall, M. J.

    The market for valve-regulated lead-acid (VRLA) batteries is growing steadily and will be given a further boost as the market for 36-V batteries for the 42-V PowerNet develops over the next few years. The manufacture of VRLA batteries poses, however, a number of complex technical problems that are not experienced in the manufacture of conventional flooded batteries. For the large-scale manufacture of automotive batteries or other small VRLA batteries of 100 Ah or less, jar formation rather than plate formation and dry charge would seem to be a logical and economically sound decision. For this to be successful, however, a number of key issues need to be reviewed, starting with a detailed consideration of battery design. This paper reviews issues associated with the jar formation of VRLA batteries. Guidance is given concerning filling techniques (gravity or vacuum fill), the formation process, charging techniques, and formation algorithms. Battery design and separator optimisation is discussed. The properties of the separator, e.g. wicking rate, fibre composition, surface area and compression, may have a critical impact on acid filling and jar formation, and may partially determine the filling and formation conditions to be used. The control of temperature during formation is particularly important. Formation algorithms and temperature data are presented. Attention is drawn to the possible loss of plate-group compression during the formation process, and how this may be avoided.

  10. HOXC9 regulates formation of parachordal lymphangioplasts and the thoracic duct in zebrafish via stabilin 2.

    Directory of Open Access Journals (Sweden)

    Sandra J Stoll

    Full Text Available HOXC9 belongs to the family of homeobox transcription factors, which are regulators of body patterning and development. HOXC9 acts as a negative regulator on blood endothelial cells but its function on lymphatic vessel development has not been studied. The hyaluronan receptor homologs stabilin 1 and stabilin 2 are expressed in endothelial cells but their role in vascular development is poorly understood. This study was aimed at investigating the function of HOXC9, stabilin 2 and stabilin 1 in lymphatic vessel development in zebrafish and in endothelial cells. Morpholino-based expression silencing of HOXC9 repressed parachordal lymphangioblast assembly and thoracic duct formation in zebrafish. HOXC9 positively regulated stabilin 2 expression in zebrafish and in HUVECs and expression silencing of stabilin 2 phenocopied the HOXC9 morphant vascular phenotype. This effect could be compensated by HOXC9 mRNA injection in stabilin 2 morphant zebrafish embryos. Stabilin 1 also regulated parachordal lymphangioblast and thoracic duct formation in zebrafish but acts independently of HOXC9. On a cellular level stabilin 1 and stabilin 2 regulated endothelial cell migration and in-gel sprouting angiogenesis in endothelial cells. HOXC9 was identified as novel transcriptional regulator of parachordal lymphangioblast assembly and thoracic duct formation in zebrafish that acts via stabilin 2. Stabilin 1, which acts independently of HOXC9, has a similar function in zebrafish and both receptors control important cellular processes in endothelial cells.

  11. Developing young adolescents’ self-regulation by means of formative assessment: A theoretical perspective

    Directory of Open Access Journals (Sweden)

    Kelly D. Meusen-Beekman

    2015-12-01

    Full Text Available Fostering self-regulated learning (SRL has become increasingly important at various educational levels. Most studies on SRL have been conducted in higher education. The present literature study aims toward understanding self-regulation processes of students in primary and secondary education. We explored the development of young students’ self-regulation from a theoretical perspective. In addition, effective characteristics for an intervention to develop young students’ self-regulation were examined, as well as the possibilities of implementing formative assessments in primary education to develop self-regulation. The results show that SRL can be supported in both primary and secondary education. However, at both school levels, differences were found, regarding the theoretical background of the training and the type of instructed strategy. Studies so far suggest avenues toward formative assessment, which seems to be a unifying theory of instruction that improves the learning process by developing self-regulation among students. But gaps in knowledge about the impact of formative assessments on the development of SRL strategies among primary school students require further exploration.

  12. The effect of M23C6 carbides on the formation of grain boundary serrations in a wrought Ni-based superalloy

    International Nuclear Information System (INIS)

    Highlights: ► The characteristics of GBS are dependent on the solution treatment conditions. ► The morphology of M23C6 carbides have a direct influence on the formation of GBS. ► The difference of diffusivity at interfaces cause M23C6 carbides and serrations. - Abstract: The effect of M23C6 carbides on the formation of grain boundary serrations (GBSs) has been systematically investigated in a solid solution strengthened Haynes 230 alloy. It is found that GBS occur in this alloy during the slow cooling process and are accompanied by the precipitation of intergranular planar M23C6 carbides. The amplitude and proportion of GBS increase with the rise of the solution temperature and time. If the specimens are cooled directly without any solution treatments, the grain boundaries remain planar and granular M23C6 carbides precipitate at them. The sequential evolutions of GBS and M23C6 carbides are investigated by scanning electron microscopy (SEM) examination. High-resolution transmission electron microscope (HRTEM) investigations reveal the coherent interfacial plane of M23C6 carbides formed at grain boundaries to be (111¯). These facts indicate that the nucleation and oriented growth of M23C6 carbides at grain boundaries play an important role in the formation of GBS. Based on the interfacial energy calculations and the tensions balance relation, a semi-quantitative model about the GBS formation is proposed.

  13. Regulation of type 1 fimbriae synthesis and biofilm formation by the transcriptional regulator LrhA of Escherichia coli.

    Science.gov (United States)

    Blumer, Caroline; Kleefeld, Alexandra; Lehnen, Daniela; Heintz, Margit; Dobrindt, Ulrich; Nagy, Gábor; Michaelis, Kai; Emödy, Levente; Polen, Tino; Rachel, Reinhard; Wendisch, Volker F; Unden, Gottfried

    2005-10-01

    Type 1 fimbriae of Escherichia coli facilitate attachment to the host mucosa and promote biofilm formation on abiotic surfaces. The transcriptional regulator LrhA, which is known as a repressor of flagellar, motility and chemotaxis genes, regulates biofilm formation and expression of type 1 fimbriae. Whole-genome expression profiling revealed that inactivation of lrhA results in an increased expression of structural components of type 1 fimbriae. In vitro, LrhA bound to the promoter regions of the two fim recombinases (FimB and FimE) that catalyse the inversion of the fimA promoter, and to the invertible element itself. Translational lacZ fusions with these genes and quantification of fimE transcript levels by real-time PCR showed that LrhA influences type 1 fimbrial phase variation, primarily via activation of FimE, which is required for the ON-to-OFF transition of the fim switch. Enhanced type 1 fimbrial expression as a result of lrhA disruption was confirmed by mannose-sensitive agglutination of yeast cells. Biofilm formation was stimulated by lrhA inactivation and completely suppressed upon LrhA overproduction. The effects of LrhA on biofilm formation were exerted via the changed levels of surface molecules, most probably both flagella and type 1 fimbriae. Together, the data show a role for LrhA as a repressor of type 1 fimbrial expression, and thus as a regulator of the initial stages of biofilm development and, presumably, bacterial adherence to epithelial host cells also. PMID:16207912

  14. Formation of Highly Misoriented Fragments at Hot Band Grain Boundaries During Cold Rolling of Interstitial-Free Steel

    Science.gov (United States)

    Afrin, Nasima; Quadir, Md. Zakaria; Ferry, Michael

    2015-07-01

    The deformation heterogeneities that form in the vicinity of prior hot band grain boundaries in a 75 pct cold-rolled interstitial-free steel have been investigated by 3D electron backscatter diffraction. Grain boundary-affected regions occupy a large fraction of the overall material volume. The coexistence of several features, such as steep orientation gradients up to 5 deg/ μm, high-angle boundary networks, and thin, elongated grain boundary fragments, has confirmed the highly complex nature of these regions. Most notably, these thin boundary fragments were found to be significantly misoriented from any of the deformed grains immediately adjacent to the boundary. Overall, grain boundary regions adopt the so-called `deformation banding' mode of deformations on both the micro ( e.g., steep gradients)- and nano ( e.g., thin fragments)-length scales. Grain boundary structures comprise the essential features to act as preferred sites for recrystallization. The discovery of numerous thin grain boundary fragments in the deformation microstructure provides a plausible explanation for the origin of recrystallized grains with orientations other than those found within the adjoining deformed grains in the vicinity of grain boundaries; this phenomenon has been commonly observed in texture data for many years but remained unexplained.

  15. THE CONTRADICTIONS OF THE FORMATION OF FUNCTIONAL AND TARGET REGULATION OF THE STOCK MARKET OF UKRAINE

    OpenAIRE

    A. Kalach

    2013-01-01

    The characteristics of formation of the inversion type of the stock market and its contradictions were investigated, the necessity of transition to a functional-target regulation of the stock market was proved the ways of optimization of the institutional system by integrating the functions of regulatory authorities were proposed.

  16. Proteins with GGDEF and EAL domains regulate Pseudomonas putida biofilm formation and dispersal

    DEFF Research Database (Denmark)

    Gjermansen, Morten; Ragas, Paula Cornelia; Tolker-Nielsen, Tim

    2006-01-01

    Microbial biofilm formation often causes problems in medical and industrial settings, and knowledge about the factors that are involved in biofilm development and dispersion is useful for creating strategies to control the processes. In this report, we present evidence that proteins with GGDEF an...... regulating the transition of bacteria between a roaming lifestyle and a sessile biofilm lifestyle....

  17. SarA is a negative regulator of Staphylococcus epidermidis biofilm formation

    DEFF Research Database (Denmark)

    Martin, Christer; Heinze, C.; Busch, M.;

    2012-01-01

    contributed to biofilm formation in mutant 1585ΔsarA. Increased eDNA amounts indirectly resulted from up-regulation of metalloprotease SepA, leading to boosted processing of major autolysin AtlE, in turn inducing augmented autolysis and release of chromosomal DNA. Hence, this study identifies sarA as a...

  18. GEOTAIL observation of tilted X-line formation during flux transfer events (FTEs in the dayside magnetospheric boundary layers

    Directory of Open Access Journals (Sweden)

    M. Nowada

    2004-09-01

    Full Text Available The magnetic field and plasma structures during two successive crossings of the subsolar magnetospheric boundary layers (i.e. MagnetoPause Current Layer (MPCL and Low-Latitude Boundary Layer (LLBL under the southward-dawnward IMF are examined on the basis of the data obtained by the GEOTAIL spacecraft. A significant and interesting feature is found, that is, Flux Transfer Events (FTEs occur in association with the formation of the tilted X-line. During the first inbound MPCL/LLBL crossing, the ion velocity enhancement (in particular, the Vl component negatively increases can be observed in association with simultaneous typical bipolar signature (positive followed by negative in the Bn component. In addition, a clear D-shaped ion distribution whose origin is the magnetosheath can also be found in the dawnward direction. A few minutes later, the satellite experiences outbound MPCL crossing. The negative enhancement of the Vm component can be found as well as the positive enhancement of the Vl component. Simultaneously, a typical bipolar signature with the polarity (negative followed by positive opposite that observed in the first encounter can also be observed. The ions from the magnetosheath flow predominantly in the duskward direction, although the D-shaped ion distribution cannot be observed. These results indicate that the satellite initially observes one part of a reconnected flux tube formed by FTEs whose magnetospheric side is anchored to the Southern Hemisphere. The ions confined in this partial flux tube are flowing in the south-dawnward direction. Then, the satellite observes the other part of the reconnected flux tube whose magnetospheric side is anchored to the Northern Hemisphere. The ions confined in this flux tube flow dominantly in the north-duskward direction. Furthermore, it can be considered that the second MPCL crossing is a direct cut through the diffusion

  19. Essential roles and regulation of the Legionella pneumophila collagen-like adhesin during biofilm formation.

    Directory of Open Access Journals (Sweden)

    Julia Mallegol

    Full Text Available Legionellosis is mostly caused by Legionella pneumophila (Lp and is defined by a severe respiratory illness with a case fatality rate ranging from 5 to 80%. In a previous study, we showed that a glycosaminoglycan (GAG-binding adhesin of Lp, named Lcl, is produced during legionellosis and is unique to the L. pneumophila species. Importantly, a mutant depleted in Lcl (Δlpg2644 is impaired in adhesion to GAGs and epithelial cells and in biofilm formation. Here, we examine the molecular function(s of Lcl and the transcriptional regulation of its encoding gene during different stages of the biofilm development. We show that the collagen repeats and the C-terminal domains of Lcl are crucial for the production of biofilm. We present evidence that Lcl is involved in the early step of surface attachment but also in intercellular interactions. Furthermore, we address the relationship between Lcl gene regulation during biofilm formation and quorum sensing (QS. In a static biofilm assay, we show that Lcl is differentially regulated during growth phases and biofilm formation. Moreover, we show that the transcriptional regulation of lpg2644, mediated by a prototype of QS signaling homoserine lactone (3OC12-HSL, may play a role during the biofilm development. Thus, transcriptional down-regulation of lpg2644 may facilitate the dispersion of Lp to reinitiate biofilm colonization on a distal surface.

  20. Essential roles and regulation of the Legionella pneumophila collagen-like adhesin during biofilm formation.

    Science.gov (United States)

    Mallegol, Julia; Duncan, Carla; Prashar, Akriti; So, Jannice; Low, Donald E; Terebeznik, Mauricio; Guyard, Cyril

    2012-01-01

    Legionellosis is mostly caused by Legionella pneumophila (Lp) and is defined by a severe respiratory illness with a case fatality rate ranging from 5 to 80%. In a previous study, we showed that a glycosaminoglycan (GAG)-binding adhesin of Lp, named Lcl, is produced during legionellosis and is unique to the L. pneumophila species. Importantly, a mutant depleted in Lcl (Δlpg2644) is impaired in adhesion to GAGs and epithelial cells and in biofilm formation. Here, we examine the molecular function(s) of Lcl and the transcriptional regulation of its encoding gene during different stages of the biofilm development. We show that the collagen repeats and the C-terminal domains of Lcl are crucial for the production of biofilm. We present evidence that Lcl is involved in the early step of surface attachment but also in intercellular interactions. Furthermore, we address the relationship between Lcl gene regulation during biofilm formation and quorum sensing (QS). In a static biofilm assay, we show that Lcl is differentially regulated during growth phases and biofilm formation. Moreover, we show that the transcriptional regulation of lpg2644, mediated by a prototype of QS signaling homoserine lactone (3OC12-HSL), may play a role during the biofilm development. Thus, transcriptional down-regulation of lpg2644 may facilitate the dispersion of Lp to reinitiate biofilm colonization on a distal surface. PMID:23029523

  1. Constraints on the upper boundary age of the Tiaojishan Formation volcanic rocks in West Liaoning-North Hebei by LA-ICP-MS dating

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; WANG MingXin; LIU XiaoMing

    2008-01-01

    In West Liaoning-North Hebei, the Tiaojishan Formation volcanic rocks are developed and many iso-topic ages with a very wide age range were obtained in them as well. These different ages have direct influence on confirming and interpreting the related geological issues in West Liaoning-North Hebei and have restricted the study of geological problems related. In the field, the Tiaojishan Formation and the overlying Tuchengzi Formation are in parallel unconformable contact. By systematical sampling and dating of LA-ICP-MS in the Tiaojishan Formation (especially in the upper part) in Luanping, Chengde basins of Northern Hebei Province and in Lingyuan, Jinlingsi-Yangshan basins of Western Liaoning Province, combined with the dating data obtained by previous researchers, results indicatethat the upper boundary age of the Tiaojishan Formation is from 156 to 153 Ma, and the lower boundary age of the Tiaojishan Formation is about 165 Ma, the Tiaojishan Formation was formed from the late of middle Jurassic to late Jurassic Epoch.

  2. Platelet receptor interplay regulates collagen-induced thrombus formation in flowing human blood.

    Science.gov (United States)

    Siljander, Pia R-M; Munnix, Imke C A; Smethurst, Peter A; Deckmyn, Hans; Lindhout, Theo; Ouwehand, Willem H; Farndale, Richard W; Heemskerk, Johan W M

    2004-02-15

    The platelet glycoproteins (GPs) Ib, integrin alpha(2)beta(1), and GPVI are considered central to thrombus formation. Recently, their relative importance has been re-evaluated based on data from murine knockout models. To examine their relationship during human thrombus formation on collagen type I fibers at high shear (1000 s(-1)), we tested a novel antibody against GPVI, an immunoglobulin single-chain variable fragment, 10B12, together with specific antagonists for GPIb alpha (12G1 Fab(2)) and alpha(2)beta(1) (6F1 mAb or GFOGER-GPP peptide). GPVI was found to be crucial for aggregate formation, Ca(2+) signaling, and phosphatidylserine (PS) exposure, but not for primary adhesion, even with more than 97% receptor blockade. Inhibiting alpha(2)beta(1) revealed its involvement in regulating Ca(2+) signaling, PS exposure, and aggregate size. Both GPIb alpha and alpha(2)beta(1) contributed to primary adhesion, showing overlapping function. The coinhibition of receptors revealed synergism in thrombus formation: the coinhibition of adenosine diphosphate (ADP) receptors with collagen receptors further decreased adhesion and aggregation, and, crucially, the complete eradication of thrombus formation required the coinhibition of GPVI with either GPIb alpha or alpha(2)beta(1). In summary, human platelet deposition on collagen depends on the concerted interplay of several receptors: GPIb in synergy with alpha(2)beta(1) mediating primary adhesion, reinforced by activation through GPVI, which further regulates the thrombus formation. PMID:14563646

  3. Sprouty2 regulates endochondral bone formation by modulation of RTK and BMP signaling.

    Science.gov (United States)

    Joo, Adriane; Long, Roger; Cheng, Zhiqiang; Alexander, Courtney; Chang, Wenhan; Klein, Ophir D

    2016-07-01

    Skeletal development is regulated by the coordinated activity of signaling molecules that are both produced locally by cartilage and bone cells and also circulate systemically. During embryonic development and postnatal bone remodeling, receptor tyrosine kinase (RTK) superfamily members play critical roles in the proliferation, survival, and differentiation of chondrocytes, osteoblasts, osteoclasts, and other bone cells. Recently, several molecules that regulate RTK signaling have been identified, including the four members of the Sprouty (Spry) family (Spry1-4). We report that Spry2 plays an important role in regulation of endochondral bone formation. Mice in which the Spry2 gene has been deleted have defective chondrogenesis and endochondral bone formation, with a postnatal decrease in skeletal size and trabecular bone mass. In these constitutive Spry2 mutants, both chondrocytes and osteoblasts undergo increased cell proliferation and impaired terminal differentiation. Tissue-specific Spry2 deletion by either osteoblast- (Col1-Cre) or chondrocyte- (Col2-Cre) specific drivers led to decreased relative bone mass, demonstrating the critical role of Spry2 in both cell types. Molecular analyses of signaling pathways in Spry2(-/-) mice revealed an unexpected upregulation of BMP signaling and decrease in RTK signaling. These results identify Spry2 as a critical regulator of endochondral bone formation that modulates signaling in both osteoblast and chondrocyte lineages. PMID:27130872

  4. Feedback-regulated star formation in molecular clouds and galactic discs

    CERN Document Server

    Faucher-Giguere, C -A; Hopkins, P F

    2013-01-01

    We present a two-zone theory for feedback-regulated star formation in galactic discs, consistently connecting the galaxy-averaged star formation law with star formation proceeding in giant molecular clouds (GMCs). Our focus is on galaxies with gas surface density Sigma_g>~100 Msun pc^-2. In our theory, the galactic disc consists of Toomre-mass GMCs embedded in a volume-filling ISM. Radiation pressure on dust disperses GMCs and most supernovae explode in the volume-filling medium. A galaxy-averaged star formation law is derived by balancing the momentum input from supernova feedback with the gravitational weight of the disc gas. This star formation law is in good agreement with observations for a CO conversion factor depending continuously on Sigma_g. We argue that the galaxy-averaged star formation efficiency per free fall time, epsilon_ff^gal, is only a weak function of the efficiency with which GMCs convert their gas into stars. This is possible because the rate limiting step for star formation is the rate ...

  5. Aggresome formation is regulated by RanBPM through an interaction with HDAC6

    Directory of Open Access Journals (Sweden)

    Louisa M. Salemi

    2014-05-01

    Full Text Available In conditions of proteasomal impairment, the build-up of damaged or misfolded proteins activates a cellular response leading to the recruitment of damaged proteins into perinuclear aggregates called aggresomes. Aggresome formation involves the retrograde transport of cargo proteins along the microtubule network and is dependent on the histone deacetylase HDAC6. Here we show that ionizing radiation (IR promotes Ran-Binding Protein M (RanBPM relocalization into discrete perinuclear foci where it co-localizes with aggresome components ubiquitin, dynein and HDAC6, suggesting that the RanBPM perinuclear clusters correspond to aggresomes. RanBPM was also recruited to aggresomes following treatment with the proteasome inhibitor MG132 and the DNA-damaging agent etoposide. Strikingly, aggresome formation by HDAC6 was markedly impaired in RanBPM shRNA cells, but was restored by re-expression of RanBPM. RanBPM was found to interact with HDAC6 and to inhibit its deacetylase activity. This interaction was abrogated by a RanBPM deletion of its LisH/CTLH domain, which also prevented aggresome formation, suggesting that RanBPM promotes aggresome formation through an association with HDAC6. Our results suggest that RanBPM regulates HDAC6 activity and is a central regulator of aggresome formation.

  6. Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets

    KAUST Repository

    SCHLEGEL, FABRICE

    2011-04-08

    Using high-resolution 3-D vortex simulations, this study seeks a mechanistic understanding of vorticity dynamics in transverse jets at a finite Reynolds number. A full no-slip boundary condition, rigorously formulated in terms of vorticity generation along the channel wall, captures unsteady interactions between the wall boundary layer and the jet - in particular, the separation of the wall boundary layer and its transport into the interior. For comparison, we also implement a reduced boundary condition that suppresses the separation of the wall boundary layer away from the jet nozzle. By contrasting results obtained with these two boundary conditions, we characterize near-field vortical structures formed as the wall boundary layer separates on the backside of the jet. Using various Eulerian and Lagrangian diagnostics, it is demonstrated that several near-wall vortical structures are formed as the wall boundary layer separates. The counter-rotating vortex pair, manifested by the presence of vortices aligned with the jet trajectory, is initiated closer to the jet exit. Moreover tornado-like wall-normal vortices originate from the separation of spanwise vorticity in the wall boundary layer at the side of the jet and from the entrainment of streamwise wall vortices in the recirculation zone on the lee side. These tornado-like vortices are absent in the case where separation is suppressed. Tornado-like vortices merge with counter-rotating vorticity originating in the jet shear layer, significantly increasing wall-normal circulation and causing deeper jet penetration into the crossflow stream. © 2011 Cambridge University Press.

  7. Original Mineralogy and Recognition of Upper Boundary of the Sarvak Formation Based on Geochemistry and Isotope Studies

    DEFF Research Database (Denmark)

    Asgari, M; Tahmasebi Poor, A; Barari, Amin

    2014-01-01

    Carbonate sequence of upper cretaceous (Cenomanian) of Sarvak Formation is a part of Bangestan Group with the thickness of 760m in Ahvaz oil field (well no. 63). This formation is overlain by the Kazhdumi Formation and is uncomfortably underlain by the Ilam Formation. In this study major and mino...

  8. The human language-associated gene SRPX2 regulates synapse formation and vocalization in mice.

    Science.gov (United States)

    Sia, G M; Clem, R L; Huganir, R L

    2013-11-22

    Synapse formation in the developing brain depends on the coordinated activity of synaptogenic proteins, some of which have been implicated in a number of neurodevelopmental disorders. Here, we show that the sushi repeat-containing protein X-linked 2 (SRPX2) gene encodes a protein that promotes synaptogenesis in the cerebral cortex. In humans, SRPX2 is an epilepsy- and language-associated gene that is a target of the foxhead box protein P2 (FoxP2) transcription factor. We also show that FoxP2 modulates synapse formation through regulating SRPX2 levels and that SRPX2 reduction impairs development of ultrasonic vocalization in mice. Our results suggest FoxP2 modulates the development of neural circuits through regulating synaptogenesis and that SRPX2 is a synaptogenic factor that plays a role in the pathogenesis of language disorders. PMID:24179158

  9. Protein kinase LKB1 regulates polarized dendrite formation of adult hippocampal newborn neurons.

    Science.gov (United States)

    Huang, Wei; She, Liang; Chang, Xing-ya; Yang, Rong-rong; Wang, Liang; Ji, Hong-bin; Jiao, Jian-wei; Poo, Mu-ming

    2014-01-01

    Adult-born granule cells in the dentate gyrus of the rodent hippocampus are important for memory formation and mood regulation, but the cellular mechanism underlying their polarized development, a process critical for their incorporation into functional circuits, remains unknown. We found that deletion of the serine-threonine protein kinase LKB1 or overexpression of dominant-negative LKB1 reduced the polarized initiation of the primary dendrite from the soma and disrupted its oriented growth toward the molecular layer. This abnormality correlated with the dispersion of Golgi apparatus that normally accumulated at the base and within the initial segment of the primary dendrite, and was mimicked by disrupting Golgi organization via altering the expression of Golgi structural proteins GM130 or GRASP65. Thus, besides its known function in axon formation in embryonic pyramidal neurons, LKB1 plays an additional role in regulating polarized dendrite morphogenesis in adult-born granule cells in the hippocampus. PMID:24367100

  10. Regulation of biofilm formation in Salmonella typhimurium and Escherichia coli Nissle 1917

    OpenAIRE

    Monteiro, Cláudia

    2011-01-01

    Bacteria have the ability to grow in cell communities designated biofilms. This mode of growth is widespread and offers numerous advantages to the bacteria in terms of survival, persistence and propagation. Bacteria have developed different ways of building up a biofilm. Complex regulatory mechanisms control this sophisticated mode of growth in response to environmental conditions. This thesis focuses on the regulation of biofilm formation by the food-borne pathogen Salmonel...

  11. ZAP-70 kinase regulates HIV cell-to-cell spread and virological synapse formation

    OpenAIRE

    Sol-Foulon, Nathalie; Sourisseau, Marion; Porrot, Françoise; Thoulouze, Maria-Isabel; Trouillet, Céline; Nobile, Cinzia; Blanchet, Fabien; Di Bartolo, Vincenzo; Noraz, Nelly; Taylor, Naomi; Alcover, Andres; Hivroz, Claire; Schwartz, Olivier

    2007-01-01

    HIV efficiently spreads in lymphocytes, likely through virological synapses (VSs). These cell–cell junctions share some characteristics with immunological synapses, but cellular proteins required for their constitution remain poorly characterized. We have examined here the role of ZAP-70, a key kinase regulating T-cell activation and immunological synapse formation, in HIV replication. In lymphocytes deficient for ZAP-70, or expressing a kinase-dead mutant of the protein, HIV replication was ...

  12. Arp2/3-mediated F-actin formation controls regulated exocytosis in vivo

    OpenAIRE

    Tran, Duy T.; Masedunskas, Andrius; Weigert, Roberto; Ten Hagen, Kelly G.

    2015-01-01

    The actin cytoskeleton plays crucial roles in many cellular processes, including regulated secretion. However, the mechanisms controlling F-actin dynamics in this process are largely unknown. Through 3D time-lapse imaging in a secreting organ, we show that F-actin is actively disassembled along the apical plasma membrane at the site of secretory vesicle fusion and re-assembled directionally on vesicle membranes. Moreover, we show that fusion pore formation and PIP2 redistribution precedes act...

  13. Feedback Regulated Star Formation: Implications for the Kennicutt-Schmidt Law

    CERN Document Server

    Dib, Sami

    2011-01-01

    We derive a metallicity dependent relation between the surface density of the star formation rate (Sigma_{SFR}) and the gas surface density (Sigma_{g}) in a feedback regulated model of star formation in galactic disks. In this model, star formation occurs in gravitationally bound protocluster clumps embedded in larger giant molecular clouds with the protocluster clump mass function following a power law function with a slope of -2 Metallicity dependent feedback is generated by the winds of OB stars (M > 5 Msol) that form in the clumps. The quenching of star formation in clumps of decreasing metallicity occurs at later epochs due to weaker wind luminosities, thus resulting in higher final star formation efficiencies (SFE_{exp}). By combining SFE_{exp} with the timescales on which gas expulsion occurs, we derive the metallicity dependent star formation rate per unit time in this model as a function of Sigma_{g}. This is combined with the molecular gas fraction in order to derive the global dependence of Sigma_{...

  14. Regulation of lamellipodia formation and cell invasion by CLIP-170 in invasive human breast cancer cells.

    Science.gov (United States)

    Suzuki, Katsuo; Takahashi, Kazuhide

    2008-04-01

    Lamellipodia formation necessary for cell invasion is regulated by Rac1. We report here that lamellipodia formation and three-dimensional invasion were significantly promoted by HGF and serum, respectively, in invasive human breast cancer cells. Rac1 formed a complex with CLIP-170, IQGAP1, and kinesin in serum-starved cells, and stimulation of the cells with HGF and serum caused the partial release of IQGAP1 and kinesin from Rac1-CLIP-170 complex. The HGF-induced release of the proteins and promotion of lamellipodia formation were inhibited by an inhibitor of PI3K. Moreover, downregulation of CLIP-170 by siRNA released IQGAP1 and kinesin from Rac1 and promoted lamellipodia formation and invasion, independent of HGF and serum. The results suggest that promotion of lamellipodia formation and invasion by HGF or serum requires PI3K-dependent release of IQGAP1 and kinesin from Rac1-CLIP-170 complex and that CLIP-170 prevents cells from the extracellular stimulus-independent lamellipodia formation and invasion by tethering IQGAP1 and kinesin to Rac1. PMID:18237546

  15. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation

    Directory of Open Access Journals (Sweden)

    Kouki eYoshida

    2013-10-01

    Full Text Available Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs can regulate secondary wall formation in rice (Oryza sativa and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S has very low transcriptional activation ability, but the longer protein (OsSWN2L and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

  16. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation.

    Science.gov (United States)

    Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

    2013-01-01

    Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications. PMID:24098302

  17. THREE-DIMENSIONAL HYDRODYNAMIC SIMULATIONS OF MULTIPHASE GALACTIC DISKS WITH STAR FORMATION FEEDBACK. I. REGULATION OF STAR FORMATION RATES

    International Nuclear Information System (INIS)

    The energy and momentum feedback from young stars has a profound impact on the interstellar medium (ISM), including heating and driving turbulence in the neutral gas that fuels future star formation. Recent theory has argued that this leads to a quasi-equilibrium self-regulated state, and for outer atomic-dominated disks results in the surface density of star formation ΣSFR varying approximately linearly with the weight of the ISM (or midplane turbulent + thermal pressure). We use three-dimensional numerical hydrodynamic simulations to test the theoretical predictions for thermal, turbulent, and vertical dynamical equilibrium, and the implied functional dependence of ΣSFR on local disk properties. Our models demonstrate that all equilibria are established rapidly, and that the expected proportionalities between mean thermal and turbulent pressures and ΣSFR apply. For outer disk regions, this results in ΣSFR∝Σ√(ρsd), where Σ is the total gas surface density and ρsd is the midplane density of the stellar disk (plus dark matter). This scaling law arises because ρsd sets the vertical dynamical time in our models (and outer disk regions generally). The coefficient in the star formation law varies inversely with the specific energy and momentum yield from massive stars. We find proportions of warm and cold atomic gas, turbulent-to-thermal pressure, and mean velocity dispersions that are consistent with solar-neighborhood and other outer disk observations. This study confirms the conclusions of a previous set of simulations, which incorporated the same physics treatment but was restricted to radial-vertical slices through the ISM

  18. New insights on molecular regulation of biofilm formation in plant-associated bacteria

    Institute of Scientific and Technical Information of China (English)

    Luisa F. Castiblanco; George W. Sundin

    2016-01-01

    Biofilms are complex bacterial assemblages with a defined three-dimensional architecture, attached to solid surfaces, and surrounded by a self-produced matrix generally composed of exopolysaccharides, proteins, lipids and extrac-ellular DNA. Biofilm formation has evolved as an adaptive strategy of bacteria to cope with harsh environmental conditions as well as to establish antagonistic or beneficial interactions with their host. Plant-associated bacteria attach and form biofilms on different tissues including leaves, stems, vasculature, seeds and roots. In this review, we examine the formation of biofilms from the plant-associated bacterial perspective and detail the recently-described mechanisms of genetic regulation used by these organisms to orchestrate biofilm formation on plant surfaces. In addition, we describe plant host signals that bacterial pathogens recognize to activate the transition from a planktonic lifestyle to multi-cellular behavior.

  19. New insights on molecular regulation of biofilm formation in plant-associated bacteria.

    Science.gov (United States)

    Castiblanco, Luisa F; Sundin, George W

    2016-04-01

    Biofilms are complex bacterial assemblages with a defined three-dimensional architecture, attached to solid surfaces, and surrounded by a self-produced matrix generally composed of exopolysaccharides, proteins, lipids and extracellular DNA. Biofilm formation has evolved as an adaptive strategy of bacteria to cope with harsh environmental conditions as well as to establish antagonistic or beneficial interactions with their host. Plant-associated bacteria attach and form biofilms on different tissues including leaves, stems, vasculature, seeds and roots. In this review, we examine the formation of biofilms from the plant-associated bacterial perspective and detail the recently-described mechanisms of genetic regulation used by these organisms to orchestrate biofilm formation on plant surfaces. In addition, we describe plant host signals that bacterial pathogens recognize to activate the transition from a planktonic lifestyle to multicellular behavior. PMID:26377849

  20. Outflow Feedback Regulated Massive Star Formation in Parsec-Scale Cluster Forming Clumps

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; /KIPAC, Menlo Park /Stanford U., Phys.Dept.; Li, Zhi-Yun; /Virginia U., Astron. Dept.; Abel, Tom; /KIPAC, Menlo Park /Stanford U., Phys.Dept.; Nakamura, Fumitaka; /Niigata U.

    2010-02-15

    We investigate massive star formation in turbulent, magnetized, parsec-scale clumps of molecular clouds including protostellar outflow feedback using three dimensional numerical simulations of effective resolution 2048{sup 3}. The calculations are carried out using a block structured adaptive mesh refinement code that solves the ideal MHD equations including self-gravity and implements accreting sink particles. We find that, in the absence of regulation by magnetic fields and outflow feedback, massive stars form readily in a turbulent, moderately condensed clump of {approx} 1,600 M{sub {circle_dot}} (containing {approx} 10{sup 2} initial Jeans masses), along with a cluster of hundreds of lower mass stars. The massive stars are fed at high rates by (1) transient dense filaments produced by large-scale turbulent compression at early times, and (2) by the clump-wide global collapse resulting from turbulence decay at late times. In both cases, the bulk of the massive star's mass is supplied from outside a 0.1 pc-sized 'core' that surrounds the star. In our simulation, the massive star is clump-fed rather than core-fed. The need for large-scale feeding makes the massive star formation prone to regulation by outflow feedback, which directly opposes the feeding processes. The outflows reduce the mass accretion rates onto the massive stars by breaking up the dense filaments that feed the massive star formation at early times, and by collectively slowing down the global collapse that fuel the massive star formation at late times. The latter is aided by a moderate magnetic field of strength in the observed range (corresponding to a dimensionless clump mass-to-flux ratio {lambda} {approx} a few); the field allows the outflow momenta to be deposited more efficiently inside the clump. We conclude that the massive star formation in our simulated turbulent, magnetized, parsec-scale clump is outflow-regulated and clump-fed (ORCF for short). An important implication

  1. Radiative effects of tropospheric aerosols on the evolution of the atmospheric boundary layer and its feedback on the haze formation

    Science.gov (United States)

    Wei, Chao; Su, Hang; Cheng, Yafang

    2016-04-01

    Planetary boundary layer (PBL) plays a key role in air pollution dispersion and influences day-to-day air quality. Some studies suggest that high aerosol loadings during severe haze events may modify PBL dynamics by radiative effects and hence enhance the development of haze. This study mainly investigates the radiative effects of tropospheric aerosols on the evolution of the atmospheric boundary layer by conducting simulations with Weather Research and Forecasting single-column model (WRF-SCM). We find that high aerosol loading in PBL depressed boundary layer height (PBLH). But the magnitude of the changes of PBLH after adding aerosol loadings in our simulations are small and can't explain extreme high aerosol concentrations observed. We also investigate the impacts of the initial temperature and moisture profiles on the evolution of PBL. Our studies show that the impact of the vertical profile of moisture is comparable with aerosol effects.

  2. Mechanism of regulation of the formate-hydrogenlyase pathway by oxygen, nitrate, and pH: definition of the formate regulon.

    Science.gov (United States)

    Rossmann, R; Sawers, G; Böck, A

    1991-11-01

    The products of a minimum of 15 genes are required for the synthesis of an active formate-hydrogenlyase (FHL) system in Escherichia coli. All are co-ordinately regulated in response to variations in the oxygen and nitrate concentration and the pH of the culture medium. Formate is obligately required for transcriptional activation of these genes. Analysis of the transcription of one of these genes, hycB linked to the lacZ reporter gene, revealed that oxygen and nitrate repression of transcription could be relieved completely, or partially in the case of nitrate, either by the addition of formate to the medium or by increasing the copy number of the gene encoding the transcriptional activator (fhlA) of this regulon. These studies uncovered a further level of regulation in which the transcription of hycB was reduced in cells grown on glucose. This effect was most clearly seen in aerobically grown cells when formate was added externally. Addition of cAMP overcame this glucose repression, which could be shown to be mediated by the cAMP receptor protein. These results would be consistent with the transport of formate being regulated by catabolite repression. Moreover, the repression of transcription through high pH also could be partially overcome by addition of increasing concentrations of formate to the medium, again being consistent with regulation at the level of formate import and export. Taken together, all these observations indicate that it is the intracellular level of formate that determines the transcription of the genes of the formate regulon by FhlA. This represents a novel positive feedback mechanism in which the activator of a regulon induces its own synthesis in response to increases in the concentration of the catabolic substrate, and this in turn is governed by the relative affinities of FhlA and the three formate dehydrogenase isoenzymes for formate. PMID:1779767

  3. A Genome-Wide Association Study for Regulators of Micronucleus Formation in Mice.

    Science.gov (United States)

    McIntyre, Rebecca E; Nicod, Jérôme; Robles-Espinoza, Carla Daniela; Maciejowski, John; Cai, Na; Hill, Jennifer; Verstraten, Ruth; Iyer, Vivek; Rust, Alistair G; Balmus, Gabriel; Mott, Richard; Flint, Jonathan; Adams, David J

    2016-01-01

    In mammals the regulation of genomic instability plays a key role in tumor suppression and also controls genome plasticity, which is important for recombination during the processes of immunity and meiosis. Most studies to identify regulators of genomic instability have been performed in cells in culture or in systems that report on gross rearrangements of the genome, yet subtle differences in the level of genomic instability can contribute to whole organism phenotypes such as tumor predisposition. Here we performed a genome-wide association study in a population of 1379 outbred Crl:CFW(SW)-US_P08 mice to dissect the genetic landscape of micronucleus formation, a biomarker of chromosomal breaks, whole chromosome loss, and extranuclear DNA. Variation in micronucleus levels is a complex trait with a genome-wide heritability of 53.1%. We identify seven loci influencing micronucleus formation (false discovery rate locus. Intriguingly at several loci we find evidence for sexual dimorphism in micronucleus formation, with a locus on chromosome 11 being specific to males. PMID:27233670

  4. AHL-type quorum sensing and its regulation on symplasmata formation in Pantoea agglomerans YS19.

    Science.gov (United States)

    Jiang, Jing; Wu, Suisui; Wang, Jieru; Feng, Yongjun

    2015-05-01

    Pantoea agglomerans YS19, an endophytic diazotrophic bacterium isolated from rice, is characterized by the formation of multicellular aggregate structure called symplasmata, which not only bestow the strong stress-resistance of the bacterium, but also contribute to the specific adaptation in the endophyte-host association. Acyl-homoserine lactones (AHLs), as the important signal molecule in the quorum sensing (QS) system of gram-negative bacteria, were demonstrated to regulate motility, cell-aggregation, and other bacterial behaviors. Here, the production of AHL by P. agglomerans YS19 and its regulation on the symplasmata formation were studied. It was revealed that the production of AHL by YS19 was initiated at the exponential growth stage and from then on, reached the peak values at the stationary growth stage in LB medium. The AHL was identified as N-3-oxooctanoyl-L-homoserine lactone (OOHL) by MALDI-TOF-MS analysis. The AHL synthesis gene pagI and receptor gene pagR in YS19 were cloned and phylogenetic analysis showed that they were high conservative among strains in species of P. agglomerans. It was revealed that AHL promoted the bacterial growth and symplasmata formation of YS19. Meanwhile, the colonization ability and growth-promoting effect of YS19 on the host plant were also enhanced by AHL. These results strongly suggest the pleiotropic effects of the AHL-type QS system in endophytic life of the strain. PMID:25283544

  5. The CUP-SHAPED COTYLEDON3 gene is required for boundary and shoot meristem formation in Arabidopsis

    DEFF Research Database (Denmark)

    Vroemen, Casper W; Mordhorst, Andreas P; Albrecht, Cathy;

    2003-01-01

    revealing an even higher degree of redundancy in this class of genes than was thought previously. The CUC3 expression pattern, the cuc3 phenotypes, and CUC3 expression in a series of shoot meristem mutants and transgenes suggest a primary role for CUC3 in the establishment of boundaries that contain cells...

  6. Formation of multiple stoichiometric phases in binary systems by combined bulk and grain boundary diffusion: Experiments and model

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Jiří; Fischer, F. D.; Schillinger, W.

    2013-01-01

    Roč. 61, č. 1 (2013), s. 32-39. ISSN 1359-6454 R&D Projects: GA ČR GAP204/10/1784 Institutional support: RVO:68081723 Keywords : Bulk diffusion * Thermodynamic modeling * Intermetallic phases * Grain-boundary diffusion Subject RIV: BJ - Thermodynamics Impact factor: 3.940, year: 2013

  7. Major contribution of neutral clusters to new particle formation at the interface between the boundary layer and the free troposphere

    OpenAIRE

    Rose, C; Sellegri, K.; Asmi, E.; Hervo, M.; Freney, E.; Colomb, A.; Junninen, H.; J. Duplissy; Sipilä, M.; Kontkanen, J.; Lehtipalo, K.; M. Kulmala

    2015-01-01

    The formation of new aerosol particles in the atmosphere is a key process influencing the aerosol number concentration as well as the climate, in particular at high altitude, where the newly formed particles directly influence cloud formation. However, free tropospheric new particle formation (NPF) is poorly documented due to logistic limitations and complex atmospheric dynamics around high-altitude stations that make the observation of this day-time process challenging. Rec...

  8. Inhibition of proliferation by PERK regulates mammary acinar morphogenesis and tumor formation.

    Directory of Open Access Journals (Sweden)

    Sharon J Sequeira

    Full Text Available Endoplasmic reticulum (ER stress signaling can be mediated by the ER kinase PERK, which phosphorylates its substrate eIF2alpha. This in turn, results in translational repression and the activation of downstream programs that can limit cell growth through cell cycle arrest and/or apoptosis. These responses can also be initiated by perturbations in cell adhesion. Thus, we hypothesized that adhesion-dependent regulation of PERK signaling might determine cell fate. We tested this hypothesis in a model of mammary acini development, a morphogenetic process regulated in part by adhesion signaling. Here we report a novel role for PERK in limiting MCF10A mammary epithelial cell proliferation during acinar morphogenesis in 3D Matrigel culture as well as in preventing mammary tumor formation in vivo. We show that loss of adhesion to a suitable substratum induces PERK-dependent phosphorylation of eIF2alpha and selective upregulation of ATF4 and GADD153. Further, inhibition of endogenous PERK signaling during acinar morphogenesis, using two dominant-negative PERK mutants (PERK-DeltaC or PERK-K618A, does not affect apoptosis but results instead in hyper-proliferative and enlarged lumen-filled acini, devoid of proper architecture. This phenotype correlated with an adhesion-dependent increase in translation initiation, Ki67 staining and upregulation of Laminin-5, ErbB1 and ErbB2 expression. More importantly, the MCF10A cells expressing PERKDeltaC, but not a vector control, were tumorigenic in vivo upon orthotopic implantation in denuded mouse mammary fat pads. Our results reveal that the PERK pathway is responsive to adhesion-regulated signals and that it is essential for proper acinar morphogenesis and in preventing mammary tumor formation. The possibility that deficiencies in PERK signaling could lead to hyperproliferation of the mammary epithelium and increase the likelihood of tumor formation, is of significance to the understanding of breast cancer.

  9. NRP1 Regulates CDC42 Activation to Promote Filopodia Formation in Endothelial Tip Cells

    Directory of Open Access Journals (Sweden)

    Alessandro Fantin

    2015-06-01

    Full Text Available Sprouting blood vessels are led by filopodia-studded endothelial tip cells that respond to angiogenic signals. Mosaic lineage tracing previously revealed that NRP1 is essential for tip cell function, although its mechanistic role in tip cells remains poorly defined. Here, we show that NRP1 is dispensable for genetic tip cell identity. Instead, we find that NRP1 is essential to form the filopodial bursts that distinguish tip cells morphologically from neighboring stalk cells, because it enables the extracellular matrix (ECM-induced activation of CDC42, a key regulator of filopodia formation. Accordingly, NRP1 knockdown and pharmacological CDC42 inhibition similarly impaired filopodia formation in vitro and in developing zebrafish in vivo. During mouse retinal angiogenesis, CDC42 inhibition impaired tip cell and vascular network formation, causing defects that resembled those due to loss of ECM-induced, but not VEGF-induced, NRP1 signaling. We conclude that NRP1 enables ECM-induced filopodia formation for tip cell function during sprouting angiogenesis.

  10. Self-regulation of charged defect compensation and formation energy pinning in semiconductors.

    Science.gov (United States)

    Yang, Ji-Hui; Yin, Wan-Jian; Park, Ji-Sang; Wei, Su-Huai

    2015-01-01

    Current theoretical analyses of defect properties without solving the detailed balance equations often estimate Fermi-level pinning position by omitting free carriers and assume defect concentrations can be always tuned by atomic chemical potentials. This could be misleading in some circumstance. Here we clarify that: (1) Because the Fermi-level pinning is determined not only by defect states but also by free carriers from band-edge states, band-edge states should be treated explicitly in the same footing as the defect states in practice; (2) defect formation energy, thus defect density, could be pinned and independent on atomic chemical potentials due to the entanglement of atomic chemical potentials and Fermi energy, in contrast to the usual expectation that defect formation energy can always be tuned by varying the atomic chemical potentials; and (3) the charged defect compensation behavior, i.e., most of donors are compensated by acceptors or vice versa, is self-regulated when defect formation energies are pinned. The last two phenomena are more dominant in wide-gap semiconductors or when the defect formation energies are small. Using NaCl and CH3NH3PbI3 as examples, we illustrate these unexpected behaviors. Our analysis thus provides new insights that enrich the understanding of the defect physics in semiconductors and insulators. PMID:26584670

  11. Dust-regulated galaxy formation and evolution: a new chemodynamical model with live dust particles

    Science.gov (United States)

    Bekki, Kenji

    2015-05-01

    Interstellar dust plays decisive roles in the conversion of neutral to molecular hydrogen (H2), the thermodynamical evolution of interstellar medium (ISM), and the modification of spectral energy distributions (SEDs) of galaxies. These important roles of dust have not been self-consistently included in previous numerical simulations of galaxy formation and evolution. We have therefore developed a new model by which one can investigate whether and how galaxy formation and evolution can be influenced by dust-related physical processes such as photoelectric heating, H2 formation on dust, and stellar radiation pressure on dust in detail. A novel point of the model is that different dust species in a galaxy are represented by `live dust' particles (i.e. not test particles). Therefore, dust particles in a galaxy not only interact gravitationally with all four components of the galaxy (i.e. dark matter, stars, gas, and dust) but also are grown and destroyed through physical processes of ISM. First, we describe a way to include dust-related physical processes in N-body+hydrodynamical simulations of galaxy evolution in detail. Then, we show some preliminary results of dust-regulated galaxy evolution. The preliminary results suggest that the evolution of dust distributions driven by radiation pressure of stars is very important for the evolution of star formation rates, chemical abundances, H2 fractions, and gas distributions in galaxies.

  12. Mcm1p-Induced DNA Bending Regulates the Formation of Ternary Transcription Factor Complexes

    OpenAIRE

    Lim, Fei-Ling; Hayes, Andrew; West, Adam G; Pic-Taylor, Aline; Darieva, Zoulfia; Morgan, Brian A; Oliver, Stephen G.; Sharrocks, Andrew D.

    2003-01-01

    The yeast MADS-box transcription factor Mcm1p plays an important regulatory role in several diverse cellular processes. In common with a subset of other MADS-box transcription factors, Mcm1p elicits substantial DNA bending. However, the role of protein-induced bending by MADS-box proteins in eukaryotic gene regulation is not understood. Here, we demonstrate an important role for Mcm1p-mediated DNA bending in determining local promoter architecture and permitting the formation of ternary trans...

  13. Synthesis and Posttranslational Regulation of Pyruvate Formate-Lyase in Lactococcus lactis

    OpenAIRE

    Melchiorsen, Claus Rix; Jokumsen, Kirsten Væver; Villadsen, John; Johnsen, Mads G.; Israelsen, Hans; Arnau, José

    2000-01-01

    The enzyme pyruvate formate-lyase (PFL) from Lactococcus lactis was produced in Escherichia coli and purified to obtain anti-PFL antibodies that were shown to be specific for L. lactis PFL. It was demonstrated that activated L. lactis PFL was sensitive to oxygen, as in E. coli, resulting in the cleavage of the PFL polypeptide. The PFL protein level and its in vivo activity and regulation were shown by Western blotting, enzyme-linked immunosorbent assay, and metabolite measurement to be depend...

  14. Dynamics of ordering in highly degenerate models with anisotropic grain-boundary potential: Effects of temperature and vortex formation

    Science.gov (United States)

    Jeppesen, Claus; Flyvbjerg, Henrik; Mouritsen, Ole G.

    1989-11-01

    Monte Carlo computer-simulation techniques are used to elucidate the equilibrium phase behavior as well as the late-stage ordering dynamics of some two-dimensional models with ground-state ordering of a high degeneracy Q. The models are Q-state Potts models with anisotropic grain-boundary potential on triangular lattices-essentially clock models, except that the potential is not a cosine, but a sine function of the angle between neighboring grain orientations. For not too small Q, these models display two thermally driven phase transitions, one which takes the system from a low-temperature Potts-ordered phase to an intermediate phase which lacks conventional long-range order, and another transition which takes the system to the high-temperature disordered phase. The linear nature of the sine potential used makes it a marginal case in the sense that it favors neither hard domain boundaries, like the standard Potts models do, nor a wetting of the boundaries, as the standard clock models do. Thermal fluctuations nevertheless cause wetting to occur for not too small temperatures. Specifically, we have studied models with Q=12 and 48. The models are quenched from infinity to zero as well as finite temperatures within the two low-temperature phases. The order parameter is a nonconserved quantity during these quenches. The nonequilibrium ordering process subsequent to the quench is studied as a function of time by calculating the interfacial energy, ΔE, associated with the entire grain-boundary network. The time evolution of this quantity is shown to obey the growth law, ΔE(t)~t-n, over an extended time range at late times. It is found that the zero-temperature dynamics is characterized by a special exponent value which for the Q=48 model is n~=0.25 in accordance with earlier work. However, for quenches to finite temperatures in the Potts-ordered phase there is a distinct crossover to the classical Lifshitz-Allen-Cahn exponent value, n=(1/2, for both values of Q. This

  15. Formation of Graphene Grain Boundaries on Cu(100) Surface and a Route Towards Their Elimination in Chemical Vapor Deposition Growth

    OpenAIRE

    Qinghong Yuan; Guangyao Song; Deyan Sun; Feng Ding

    2014-01-01

    Grain boundaries (GBs) in graphene prepared by chemical vapor deposition (CVD) greatly degrade the electrical and mechanical properties of graphene and thus hinder the applications of graphene in electronic devices. The seamless stitching of graphene flakes can avoid GBs, wherein the identical orientation of graphene domain is required. In this letter, the graphene orientation on one of the most used catalyst surface — Cu(100) surface, is explored by density functional theory (DFT) calculatio...

  16. Dynamics of ordering in highly degenerate models with anisotropic grain-boundary potential: Effects of temperature and vortex formation

    DEFF Research Database (Denmark)

    Jeppesen, Claus; Flyvbjerg, Henrik; Mouritsen, Ole G.

    1989-01-01

    universality class, and that all models with nonconserved order parameter, independent of ordering degeneracy and softness and origin of domain boundaries, obey the classical growth law at finite temperatures. In quenches to the Potts-ordered phase vortices and antivortices occur and annihilate mutually...... without pinning the ordering process. The ordering dynamics for quenches into the intermediate phase is also found to be described by an effectively algebraic growth law....

  17. Palynology of the Lost Branch Formation of Kansas - New insights on the major floral transition at the Middle-Upper Pennsylvanian boundary

    Science.gov (United States)

    Peppers, R.A.

    1997-01-01

    Palynological assemblages from two outcrops of the upper part of the Memorial Formation, the Lost Branch Formation, and the overlying Hepler unit in Kansas were examined to discover which stratigraphic interval marks the change from the lycopod-dominated coal swamp floras of Middle Pennsylvanian (Westphalian D) age to the fern-dominated coal swamp floras of Late Pennsylvanian (Stephanian) age. The Lost Branch Formation underlies the Pleasanton Group, whose base is recognized as the Middle-Upper Pennsylvanian boundary in the Midcontinent. The outcrops include the youngest Middle Pennsylvanian coal (Dawson), just below the Lost Branch Formation, and the oldest Upper Pennsylvanian coal ('Hepler') within the Pleasanton Group. Lycospora dominates the spore assemblage in the Middle Pennsylvanian (Desmoinesian) Dawson coal in the Memorial Shale and is abundant in shale between the coal and just below the Glenpool limestone bed at the top of the Lost Branch Formation. It is rare between the limestone and the Upper Pennsylvanian (Missourian) 'Hepler' coal. Granasporites medius and Thymospora pseudothiessenii disappear below the limestone. The 'Hepler' coal is dominated by fern and seed fern spores Cyclogranisporites and Apiculatasporites, and the sphenopsid spore Calamospora is third in abundance. Florinites, Potonieisporites and other gymnospermic monosaccate pollen are abundant between the two coals. Bisaccate conifer-like pollen, such as Protohaploxipinus, are most common between the Dawson coal and Glenpool limestone, but Wilsonites, which is thought to have been produced by seed ferns, is very abundant from the Glenpool limestone to the 'Hepler' coal. On the basis of macroinvertebrate evidence, the Glenpool limestone is Middle Pennsylvanian in age, but the palynological evidence indicates that the floral change took place slightly before deposition of the limestone. Thus, the major change in climate that occurred near the Middle-Upper Pennsylvanian boundary apparently

  18. Regulation of star formation in giant galaxies by precipitation, feedback and conduction.

    Science.gov (United States)

    Voit, G M; Donahue, M; Bryan, G L; McDonald, M

    2015-03-12

    The Universe's largest galaxies reside at the centres of galaxy clusters and are embedded in hot gas that, if left undisturbed, would cool quickly and create many more new stars than are actually observed. Cooling can be regulated by feedback from accretion of cooling gas onto the central black hole, but requires an accretion rate finely tuned to the thermodynamic state of the hot gas. Theoretical models in which cold clouds precipitate out of the hot gas via thermal instability and accrete onto the black hole exhibit the necessary tuning. Recent observational evidence shows that the abundance of cold gas in the centres of clusters increases rapidly near the predicted threshold for instability. Here we report observations showing that this precipitation threshold extends over a large range in cluster radius, cluster mass and cosmic time. We incorporate the precipitation threshold into a framework of theoretical models for the thermodynamic state of hot gas in galaxy clusters. According to that framework, precipitation regulates star formation in some giant galaxies, while thermal conduction prevents star formation in others if it can compensate for radiative cooling and shut off precipitation. PMID:25739501

  19. Using Formative Assessment and Self-Regulated Learning to Help Developmental Mathematics Students Achieve: A Multi-Campus Program

    Science.gov (United States)

    Hudesman, John; Crosby, Sara; Ziehmke, Niesha; Everson, Howard; Issac, Sharlene; Flugman, Bert; Zimmerman, Barry; Moylan, Adam

    2014-01-01

    The authors describe an Enhanced Formative Assessment and Self-Regulated Learning (EFA-SRL) program designed to improve the achievement of community college students enrolled in developmental mathematics courses. Their model includes the use of specially formatted quizzes designed to assess both the students' mathematics and metacognitive…

  20. Prostaglandin E2 regulates melanocyte dendrite formation through activation of PKCζ

    International Nuclear Information System (INIS)

    Prostaglandins are lipid signaling intermediates released by keratinocytes in response to ultraviolet irradiation (UVR) in the skin. The main prostaglandin released following UVR is PGE2, a ligand for 4 related G-protein-coupled receptors (EP1, EP2, EP3 and EP4). Our previous work established that PGE2 stimulates melanocyte dendrite formation through activation of the EP1 and EP3 receptors. The purpose of the present report is to define the signaling intermediates involved in EP1- and EP3-dependent dendrite formation in human melanocytes. We recently showed that activation of the atypical PKCζ isoform stimulates melanocyte dendricity in response to treatment with lysophosphatidylcholine. We therefore examined the potential contribution of PKCζ activation on EP1- and EP3-dependent dendrite formation in melanocytes. Stimulation of the EP1 and EP3 receptors by selective agonists activated PKCζ, and inhibition of PKCζ activation abrogated EP1- and EP3-receptor-mediated melanocyte dendricity. Because of the importance of Rho-GTP binding proteins in the regulation of melanocyte dendricity, we also examined the effect of EP1 and EP3 receptor activation on Rac and Rho activity. Neither Rac nor Rho was activated upon treatment with EP1,3-receptor agonists. We show that melanocytes express only the EP3A1 isoform, but not the EP3B receptor isoform, previously associated with Rho activation, consistent with a lack of Rho stimulation by EP3 agonists. Our data suggest that PKCζ activation plays a predominant role in regulation of PGE2-dependent melanocyte dendricity

  1. Magnetically Regulated Star Formation in Three Dimensions: The Case of the Taurus Molecular Cloud Complex

    Science.gov (United States)

    Nakamura, Fumitaka; Li, Zhi-Yun

    2008-11-01

    We carry out three-dimensional MHD simulations of star formation in turbulent, magnetized clouds, including ambipolar diffusion and feedback from protostellar outflows. The calculations focus on relatively diffuse clouds threaded by a strong magnetic field capable of resisting severe tangling by turbulent motions and retarding global gravitational contraction in the cross field direction. They are motivated by observations of the Taurus molecular cloud complex (and, to a lesser extent, Pipe Nebula), which shows an ordered large-scale magnetic field, as well as elongated condensations that are generally perpendicular to the large-scale field. We find that stars form in earnest in such clouds when enough material has settled gravitationally along the field lines that the mass-to-flux ratios of the condensations approach the critical value. Only a small fraction (of order 1% or less) of the nearly magnetically critical, condensed material is turned into stars per local free-fall time, however. The slow star formation takes place in condensations that are moderately supersonic; it is regulated primarily by magnetic fields, rather than turbulence. The quiescent condensations are surrounded by diffuse halos that are much more turbulent, as observed in the Taurus complex. Strong support for magnetic regulation of star formation in this complex comes from the extremely slow conversion of the already condensed, relatively quiescent C18O gas into stars, at a rate 2 orders of magnitude below the maximum, free-fall value. We analyze the properties of dense cores, including their mass spectrum, which resembles the stellar initial mass function.

  2. AMP-activated protein kinase (AMPK) activation regulates in vitro bone formation and bone mass.

    Science.gov (United States)

    Shah, M; Kola, B; Bataveljic, A; Arnett, T R; Viollet, B; Saxon, L; Korbonits, M; Chenu, C

    2010-08-01

    Adenosine 5'-monophosphate-activated protein kinase (AMPK), a regulator of energy homeostasis, has a central role in mediating the appetite-modulating and metabolic effects of many hormones and antidiabetic drugs metformin and glitazones. The objective of this study was to determine if AMPK can be activated in osteoblasts by known AMPK modulators and if AMPK activity is involved in osteoblast function in vitro and regulation of bone mass in vivo. ROS 17/2.8 rat osteoblast-like cells were cultured in the presence of AMPK activators (AICAR and metformin), AMPK inhibitor (compound C), the gastric peptide hormone ghrelin and the beta-adrenergic blocker propranolol. AMPK activity was measured in cell lysates by a functional kinase assay and AMPK protein phosphorylation was studied by Western Blotting using an antibody recognizing AMPK Thr-172 residue. We demonstrated that treatment of ROS 17/2.8 cells with AICAR and metformin stimulates Thr-172 phosphorylation of AMPK and dose-dependently increases its activity. In contrast, treatment of ROS 17/2.8 cells with compound C inhibited AMPK phosphorylation. Ghrelin and propranolol dose-dependently increased AMPK phosphorylation and activity. Cell proliferation and alkaline phosphatase activity were not affected by metformin treatment while AICAR significantly inhibited ROS 17/2.8 cell proliferation and alkaline phosphatase activity at high concentrations. To study the effect of AMPK activation on bone formation in vitro, primary osteoblasts obtained from rat calvaria were cultured for 14-17days in the presence of AICAR, metformin and compound C. Formation of 'trabecular-shaped' bone nodules was evaluated following alizarin red staining. We demonstrated that both AICAR and metformin dose-dependently increase trabecular bone nodule formation, while compound C inhibits bone formation. When primary osteoblasts were co-treated with AICAR and compound C, compound C suppressed the stimulatory effect of AICAR on bone nodule formation

  3. Becoming popular: Interpersonal emotion regulation predicts relationship formation in real life social networks

    Directory of Open Access Journals (Sweden)

    Karen eNiven

    2015-09-01

    Full Text Available Building relationships is crucial for satisfaction and success, especially when entering new social contexts. In the present paper, we investigate whether attempting to improve others’ feelings helps people to make connections in new networks. In Study 1, a social network study following new networks of people for a twelve-week period indicated that use of interpersonal emotion regulation (IER strategies predicted growth in popularity, as indicated by other network members’ reports of spending time with the person, in work and non-work interactions. In Study 2, linguistic analysis of the tweets from over 8000 Twitter users from formation of their accounts revealed that use of IER predicted greater popularity in terms of the number of followers gained. However, not all types of IER had positive effects. Behavioral IER strategies (which use behavior to reassure or comfort in order to regulate affect were associated with greater popularity, while cognitive strategies (which change a person’s thoughts about his or her situation or feelings in order to regulate affect were negatively associated with popularity. Our findings have implications for our understanding of how new relationships are formed, highlighting the important the role played by intentional emotion regulatory processes.

  4. Dynamics of ordering in highly degenerate models with anisotropic grain-boundary potential: Effects of temperature and vortex formation

    OpenAIRE

    Jeppesen, Claus; Flyvbjerg, Henrik; Ole G. Mouritsen

    1989-01-01

    Monte Carlo computer-simulation techniques are used to elucidate the equilibrium phase behavior as well as the late-stage ordering dynamics of some two-dimensional models with ground-state ordering of a high degeneracy, Q. The models are Q-state Potts models with anisotropic grain-boundary potential on triangular lattices—essentially clock models, except that the potential is not a cosine, but a sine function of the angle between neighboring grain orientations. For not too small Q, these mode...

  5. Epigenetic regulations of immediate early genes expression involved in memory formation by the amyloid precursor protein of Alzheimer disease

    OpenAIRE

    Hendrickx, Aurélie; Pierrot, Nathalie; Tasiaux, Bernadette; Schakman, Olivier; Kienlen-Campard, Pascal; De Smet, Charles; Octave, Jean-Noël

    2014-01-01

    We previously demonstrated that APP epigenetically regulates Egr1 expression both in cultured neurons and in vivo. Since Egr1 is an immediate early gene involved in memory formation, we wondered whether other early genes involved in memory were regulated by APP and we studied molecular mechanisms involved. By comparing prefrontal (PF) cortex from wild type (APP+/+) and APP knockout mice (APP-/-), we observed that APP down regulates expression of four immediate early genes, Egr1, c-Fos, Bdnf a...

  6. Epigenetic Regulations of Immediate Early Genes Expression Involved in Memory Formation by the Amyloid Precursor Protein of Alzheimer Disease

    OpenAIRE

    Hendrickx, Aurélie; Pierrot, Nathalie; Tasiaux, Bernadette; Schakman, Olivier; Kienlen-Campard, Pascal; De Smet, Charles; Octave, Jean-Noël

    2014-01-01

    We previously demonstrated that APP epigenetically regulates Egr1 expression both in cultured neurons and in vivo. Since Egr1 is an immediate early gene involved in memory formation, we wondered whether other early genes involved in memory were regulated by APP and we studied molecular mechanisms involved. By comparing prefrontal (PF) cortex from wild type (APP+/+) and APP knockout mice (APP−/−), we observed that APP down regulates expression of four immediate early genes, Egr1, c-Fos, Bdnf a...

  7. THE FORMATION OF ENTS ADAPTIVE REACTIONS DEPENDING ON THE TYPE OF PSYCHO-VEGETATIVE REGULATION

    Directory of Open Access Journals (Sweden)

    E. M. Kazin

    2014-01-01

    Full Text Available The purpose of the students (12 to 15 years old examination was to identify the integrative criteria of assessing the nature of the functional relationships between the parameters of the psychosocial and physiological adaptation of students, depending on age, individual-typological peculiarities of vegetative regulation, personal potential at different stages of school education.The study of the characteristics of vegetative regulation of the cardiovascular system was made with a help of an automatic cardiac-rhythm programs. The research of psychophysiological parameters was fulfiled using an automatic complex. The measurement of the speed of simple visual-motor reaction (PSMR, reaction to a moving object (WFD, the level of functional mobility of nervous processes (WFP and health brain (DDM were made before. Features psychosocial adaptation was analyzed using 8-color Luscher test.All examinee were divided into three groups on the basis of the statistical characteristics of the cardiac rhythm by the tone source autonomic tone: “vagotonia” (with a predominance of parasympathetic sistems, “somatotonic” (with domination of the sympatholytic effects, “atonic” (balanced type of vegetative nervous system.Based on the analysis of psychodynamic, neurodynamic and vegetative functions showed that students with initial vagotonies tone are characterized by high levels of situational and personal anxiety, low psychosocial adaptation, decreased activity of neurodynamic functions and psychodynamic processes in the learning dynamics, whereas the individuals with dominance of sympatotonics type regulation have high level of neurodynamic processes, psychosocial adaptation, against the background of significant stress mechanisms of vegetative regulation.Students with initial vegetative tone demonstrate a sufficient level of psychosocial adaptation, activity psychodynamic and neuromotor processes, accompanied by the preservation of the functionality of

  8. Formation of Graphene Grain Boundaries on Cu(100) Surface and a Route Towards Their Elimination in Chemical Vapor Deposition Growth

    Science.gov (United States)

    Yuan, Qinghong; Song, Guangyao; Sun, Deyan; Ding, Feng

    2014-10-01

    Grain boundaries (GBs) in graphene prepared by chemical vapor deposition (CVD) greatly degrade the electrical and mechanical properties of graphene and thus hinder the applications of graphene in electronic devices. The seamless stitching of graphene flakes can avoid GBs, wherein the identical orientation of graphene domain is required. In this letter, the graphene orientation on one of the most used catalyst surface -- Cu(100) surface, is explored by density functional theory (DFT) calculations. Our calculation demonstrates that a zigzag edged hexagonal graphene domain on a Cu(100) surface has two equivalent energetically preferred orientations, which are 30 degree away from each other. Therefore, the fusion of graphene domains on Cu(100) surface during CVD growth will inevitably lead to densely distributed GBs in the synthesized graphene. Aiming to solve this problem, a simple route, that applies external strain to break the symmetry of the Cu(100) surface, was proposed and proved efficient.

  9. Formation of graphene grain boundaries on Cu(100) surface and a route towards their elimination in chemical vapor deposition growth.

    Science.gov (United States)

    Yuan, Qinghong; Song, Guangyao; Sun, Deyan; Ding, Feng

    2014-01-01

    Grain boundaries (GBs) in graphene prepared by chemical vapor deposition (CVD) greatly degrade the electrical and mechanical properties of graphene and thus hinder the applications of graphene in electronic devices. The seamless stitching of graphene flakes can avoid GBs, wherein the identical orientation of graphene domain is required. In this letter, the graphene orientation on one of the most used catalyst surface - Cu(100) surface, is explored by density functional theory (DFT) calculations. Our calculation demonstrates that a zigzag edged hexagonal graphene domain on a Cu(100) surface has two equivalent energetically preferred orientations, which are 30 degree away from each other. Therefore, the fusion of graphene domains on Cu(100) surface during CVD growth will inevitably lead to densely distributed GBs in the synthesized graphene. Aiming to solve this problem, a simple route, that applies external strain to break the symmetry of the Cu(100) surface, was proposed and proved efficient. PMID:25286970

  10. The geological significance of the boundary between the Fort Sill and Signal Mountain Formations in the lower Arbuckle Group (Cambrian)

    Energy Technology Data Exchange (ETDEWEB)

    Hosey, R.; Donovan, R.N. (Texas Christian Univ., Ft Worth, TX (United States). Geology Dept.)

    1993-02-01

    During the upper Cambrian, a transgression inundated the Southern Oklahoma aulacogen enveloping a landscape that consisted of hills of Cambrian-aged rhyolite up to 350 m in height. Initial deposits on this topography--the Reagan Formation--consist of siliciclastics that were deposited as alluvium and succeeding tidally-influenced marine sandstones and shales. The siliciclastics grains are made up of local rhyolite, quartz and authigenic glauconite. The overlying Honeycreek Formation is defined by the addition of carbonated detritus in the form of tidally-influenced pelmatozoan grainstones. The passage from the Honeycreek to the overlying Fort Sill Formation of the Arbuckle Group is marked by the incoming of beds of lime mudstone and the gradual disappearance of grainstones and siliciclastics. The contact between the Fort Sill and the overlying thinly-bedded dark grey bioclastic limestones of the Signal Mountain Formation is one of the most distinctive horizons in the Arbuckle Group. The contact evidently marks a substantial change in depositional environment. In detail the contact is sharp and shows evidence of minor erosion, although no karsting has been detected. The authors suggest that the contact surface records a regression, perhaps associated with dolomitization and followed by some erosion. A regression is also indicated by the local occurrence of a laminated tidal flat unit with traces of evaporites that outcrops in the far west of the Slick Hills immediately below the formation contact. They suggest that the Signal Mountains as a transgressive unit, incorporating siliciclastics transported into the area during the regression. It has been suggested that the unconformity reflects localized tectonism associated with the evolution of the Southern Oklahoma aulacogen. On the other hand the surface may correlate with a craton--wide Sauxian' hiatus.

  11. Ras-Mek-Erk signaling regulates Nf1 heterozygous neointima formation.

    Science.gov (United States)

    Stansfield, Brian K; Bessler, Waylan K; Mali, Raghuveer; Mund, Julie A; Downing, Brandon D; Kapur, Reuben; Ingram, David A

    2014-01-01

    Neurofibromatosis type 1 (NF1) results from mutations in the NF1 tumor-suppressor gene, which encodes neurofibromin, a negative regulator of diverse Ras signaling cascades. Arterial stenosis is a nonneoplastic manifestation of NF1 that predisposes some patients to debilitating morbidity and sudden death. Recent murine studies demonstrate that Nf1 heterozygosity (Nf1(+/-)) in monocytes/macrophages significantly enhances intimal proliferation after arterial injury. However, the downstream Ras effector pathway responsible for this phenotype is unknown. Based on in vitro assays demonstrating enhanced extracellular signal-related kinase (Erk) signaling in Nf1(+/-) macrophages and vascular smooth muscle cells and in vivo evidence of Erk amplification without alteration of phosphatidylinositol 3-kinase signaling in Nf1(+/-) neointimas, we tested the hypothesis that Ras-Erk signaling regulates intimal proliferation in a murine model of NF1 arterial stenosis. By using a well-established in vivo model of inflammatory cell migration and standard cell culture, neurofibromin-deficient macrophages demonstrate enhanced sensitivity to growth factor stimulation in vivo and in vitro, which is significantly diminished in the presence of PD0325901, a specific inhibitor of Ras-Erk signaling in phase 2 clinical trials for cancer. After carotid artery injury, Nf1(+/-) mice demonstrated increased intimal proliferation compared with wild-type mice. Daily administration of PD0325901 significantly reduced Nf1(+/-) neointima formation to levels of wild-type mice. These studies identify the Ras-Erk pathway in neurofibromin-deficient macrophages as the aberrant pathway responsible for enhanced neointima formation. PMID:24211110

  12. Transcriptional profiling reveals regulated genes in the hippocampus during memory formation

    Science.gov (United States)

    Donahue, Christine P.; Jensen, Roderick V.; Ochiishi, Tomoyo; Eisenstein, Ingrid; Zhao, Mingrui; Shors, Tracey; Kosik, Kenneth S.

    2002-01-01

    Transcriptional profiling (TP) offers a powerful approach to identify genes activated during memory formation and, by inference, the molecular pathways involved. Trace eyeblink conditioning is well suited for the study of regional gene expression because it requires the hippocampus, whereas the highly parallel task, delay conditioning, does not. First, we determined when gene expression was most regulated during trace conditioning. Rats were exposed to 200 trials per day of paired and unpaired stimuli each day for 4 days. Changes in gene expression were most apparent 24 h after exposure to 200 trials. Therefore, we profiled gene expression in the hippocampus 24 h after 200 trials of trace eyeblink conditioning, on multiple arrays using additional animals. Of 1,186 genes on the filter array, seven genes met the statistical criteria and were also validated by real-time polymerase chain reaction. These genes were growth hormone (GH), c-kit receptor tyrosine kinase (c-kit), glutamate receptor, metabotropic 5 (mGluR5), nerve growth factor-beta (NGF-beta), Jun oncogene (c-Jun), transmembrane receptor Unc5H1 (UNC5H1), and transmembrane receptor Unc5H2 (UNC5H2). All these genes, except for GH, were downregulated in response to trace conditioning. GH was upregulated; therefore, we also validated the downregulation of the GH inhibitor, somatostatin (SST), even though it just failed to meet criteria on the arrays. By during situ hybridization, GH was expressed throughout the cell layers of the hippocampus in response to trace conditioning. None of the genes regulated in trace eyeblink conditioning were similarly affected by delay conditioning, a task that does not require the hippocampus. These findings demonstrate that transcriptional profiling can exhibit a repertoire of genes sensitive to the formation of hippocampal-dependent associative memories.

  13. Response regulator heterodimer formation controls a key stage in Streptomyces development.

    Directory of Open Access Journals (Sweden)

    Mahmoud M Al-Bassam

    2014-08-01

    Full Text Available The orphan, atypical response regulators BldM and WhiI each play critical roles in Streptomyces differentiation. BldM is required for the formation of aerial hyphae, and WhiI is required for the differentiation of these reproductive structures into mature spores. To gain insight into BldM function, we defined the genome-wide BldM regulon using ChIP-Seq and transcriptional profiling. BldM target genes clustered into two groups based on their whi gene dependency. Expression of Group I genes depended on bldM but was independent of all the whi genes, and biochemical experiments showed that Group I promoters were controlled by a BldM homodimer. In contrast, Group II genes were expressed later than Group I genes and their expression depended not only on bldM but also on whiI and whiG (encoding the sigma factor that activates whiI. Additional ChIP-Seq analysis showed that BldM Group II genes were also direct targets of WhiI and that in vivo binding of WhiI to these promoters depended on BldM and vice versa. We go on to demonstrate that BldM and WhiI form a functional heterodimer that controls Group II promoters, serving to integrate signals from two distinct developmental pathways. The BldM-WhiI system thus exemplifies the potential of response regulator heterodimer formation as a mechanism to expand the signaling capabilities of bacterial cells.

  14. The ARCHIMEDE-ARGILE project: acquisition and regulation of the water chemistry in a clay formation

    International Nuclear Information System (INIS)

    The first aim of the CEC/ANDRA project known as ARCHIMEDE-ARGILE is to gain an understanding on the mechanisms of acquisition and regulation of the water chemistry in a clay environment. This step is essential for predicting both the behaviour and the migration in solution of artificial elements which are initially absent in clay formation. The second aim is to assess sampling methodology and data collection techniques for key physico-chemical parameters (pH, Eh, pCO2, CEC, alkalinity...) which are the basis of the geochemical modelling of the behaviour of natural and artificial radioelements. Six drill holes have been performed in 1992 in the sliding ribs gallery in the Underground Research Facility (URF) at Mol. The study has demonstrated the importance of in situ measurements for key parameters that cannot be rigorously evaluated otherwise: redox, pH, pCO2. Fluid geochemistry can realistically be modelled using equilibrium models, in which cation exchange must be taken into account. Bacterial studies have revealed the importance of human activity on the microbial equilibrium of the formation. This paper presents the main results obtained during the first two years of the project with emphasis on determination of the hydrochemical characteristics of the Boom clay. (author). 12 refs., 4 figs., 1 tab

  15. A TNF-regulated recombinatorial macrophage immune receptor implicated in granuloma formation in tuberculosis.

    Directory of Open Access Journals (Sweden)

    Alexander W Beham

    2011-11-01

    Full Text Available Macrophages play a central role in host defense against mycobacterial infection and anti- TNF therapy is associated with granuloma disorganization and reactivation of tuberculosis in humans. Here, we provide evidence for the presence of a T cell receptor (TCR αβ based recombinatorial immune receptor in subpopulations of human and mouse monocytes and macrophages. In vitro, we find that the macrophage-TCRαβ induces the release of CCL2 and modulates phagocytosis. TNF blockade suppresses macrophage-TCRαβ expression. Infection of macrophages from healthy individuals with mycobacteria triggers formation of clusters that express restricted TCR Vβ repertoires. In vivo, TCRαβ bearing macrophages abundantly accumulate at the inner host-pathogen contact zone of caseous granulomas from patients with lung tuberculosis. In chimeric mouse models, deletion of the variable macrophage-TCRαβ or TNF is associated with structurally compromised granulomas of pulmonary tuberculosis even in the presence of intact T cells. These results uncover a TNF-regulated recombinatorial immune receptor in monocytes/macrophages and demonstrate its implication in granuloma formation in tuberculosis.

  16. Feedback Regulated Turbulence, Magnetic Fields, and Star Formation Rates in Galactic Disks

    CERN Document Server

    Kim, Chang-Goo

    2015-01-01

    We use three-dimensional magnetohydrodynamic (MHD) simulations to investigate the quasi-equilibrium states of galactic disks regulated by star formation feedback. We incorporate effects from massive-star feedback via time-varying heating rates and supernova (SN) explosions. We find that the disks in our simulations rapidly approach a quasi-steady state that satisfies vertical dynamical equilibrium. The star formation rate (SFR) surface density self-adjusts to provide the total momentum flux (pressure) in the vertical direction that matches the weight of the gas. We quantify feedback efficiency by measuring feedback yields, \\eta_c\\equiv P_c/\\Sigma_SFR (in suitable units), for each pressure component. The turbulent and thermal feedback yields are the same for HD and MHD simulations, \\eta_th~1 and \\eta_ turb~4, consistent with the theoretical expectations. In MHD simulations, turbulent magnetic fields are rapidly generated by turbulence, and saturate at a level corresponding to \\eta_mag,t~1. The presence of magn...

  17. Inhibition of quorum sensing regulated biofilm formation in Serratia marcescens causing nosocomial infections.

    Science.gov (United States)

    Bakkiyaraj, Dhamodharan; Sivasankar, Chandran; Pandian, Shunmugiah Karutha

    2012-05-01

    Serratia marcescens is an opportunistic pathogen causing severe urinary tract infections in hospitalized individuals. Infections of S. marcescens are of great concern because of its increasing resistance towards conventional antibiotics. Quorum sensing (QS)-a cell to cell communication-system of S. marcescens acts as a global regulator of almost all the virulence factors and majorly its biofilm formation. Since, the QS system of S. marcescens directly accords to its pathogenesis, targeting QS system will provide an improved strategy to combat drug resistant pathogens. In the present study, QS system of S. marcescens has been used as target and its inhibition has been studied upon exposure to bioactives from coral associated bacteria (CAB). This study also emphasises the potential of CAB in producing bioactive agents with anti-QS and antibiofilm properties. Two CAB isolates CAB 23 and 41 have shown to inhibit biofilm formation and the production of QS dependent virulence factors like prodigiosin, protease, lipase and swarming motility. The study, on the whole explicates the potential of QS system as a target to treat drug resistant bacterial infections. PMID:22487181

  18. DNA Methylation Dynamics Regulate the Formation of a Regenerative Wound Epithelium during Axolotl Limb Regeneration.

    Directory of Open Access Journals (Sweden)

    Cristian Aguilar

    Full Text Available The formation of a blastema during regeneration of an axolotl limb involves important changes in the behavior and function of cells at the site of injury. One of the earliest events is the formation of the wound epithelium and subsequently the apical epidermal cap, which involves in vivo dedifferentiation that is controlled by signaling from the nerve. We have investigated the role of epigenetic modifications to the genome as a possible mechanism for regulating changes in gene expression patterns of keratinocytes of the wound and blastema epithelium that are involved in regeneration. We report a modulation of the expression DNMT3a, a de novo DNA methyltransferase, within the first 72 hours post injury that is dependent on nerve signaling. Treatment of skin wounds on the upper forelimb with decitabine, a DNA methyltransferase inhibitor, induced changes in gene expression and cellular behavior associated with a regenerative response. Furthermore, decitabine-treated wounds were able to participate in regeneration while untreated wounds inhibited a regenerative response. Elucidation of the specific epigenetic modifications that mediate cellular dedifferentiation likely will lead to insights for initiating a regenerative response in organisms that lack this ability.

  19. Regulated Formation of lncRNA-DNA Hybrids Enables Faster Transcriptional Induction and Environmental Adaptation.

    Science.gov (United States)

    Cloutier, Sara C; Wang, Siwen; Ma, Wai Kit; Al Husini, Nadra; Dhoondia, Zuzer; Ansari, Athar; Pascuzzi, Pete E; Tran, Elizabeth J

    2016-02-01

    Long non-coding (lnc)RNAs, once thought to merely represent noise from imprecise transcription initiation, have now emerged as major regulatory entities in all eukaryotes. In contrast to the rapidly expanding identification of individual lncRNAs, mechanistic characterization has lagged behind. Here we provide evidence that the GAL lncRNAs in the budding yeast S. cerevisiae promote transcriptional induction in trans by formation of lncRNA-DNA hybrids or R-loops. The evolutionarily conserved RNA helicase Dbp2 regulates formation of these R-loops as genomic deletion or nuclear depletion results in accumulation of these structures across the GAL cluster gene promoters and coding regions. Enhanced transcriptional induction is manifested by lncRNA-dependent displacement of the Cyc8 co-repressor and subsequent gene looping, suggesting that these lncRNAs promote induction by altering chromatin architecture. Moreover, the GAL lncRNAs confer a competitive fitness advantage to yeast cells because expression of these non-coding molecules correlates with faster adaptation in response to an environmental switch. PMID:26833086

  20. Location, formation and biosynthetic regulation of cellulases in the gliding bacteria Cytophaga hutchinsonii

    Directory of Open Access Journals (Sweden)

    Elijah Johnson

    2006-01-01

    Full Text Available An analysis of the recently published genome sequence of Cytophagahutchinsonii revealed an unusual collection of genes for an organism that can attackcrystalline cellulose. Consequently, questions were being raised by cellulase scientists, as towhat mechanism this organism uses to degrade its insoluble substrates. Cellulose, being ahighly polymeric compound and insoluble in water, cannot enter the cell walls ofmicroorganisms. Cellulose-degrading enzymes have therefore to be located on the surface ofthe cell wall or released extracellularly. The location of most cellulase enzymes has beenstudied. However, basic information on C. hutchinsonii cellulases is almost non-existent. Inthe present study, the location, formation and biosynthetic regulation of cellulases in C.hutchinsonii were demonstrated on different substrates. Various fractions isolated from C.hutchinsonii after cell rupture were assayed for carboxymethyl-cellulase activity (CMC.The cellulases were found to be predominantly cell-free during active growth on solka-flok,although 30% of activity was recorded on cell-bound enzymes. Relatively little CM-cellulase was formed when cells were grown on glucose and cellobiose. Apparently glucoseor labile substrates such as cellobiose seem to repress the formation of CM-cellulase. Thesefindings should provide some insight into possible hydrolysis mechanisms by C.hutchinsonii.

  1. Regulation of ice stream flow through subglacial formation of gas hydrates

    Science.gov (United States)

    Winsborrow, Monica; Andreassen, Karin; Hubbard, Alun; Plaza-Faverola, Andreia; Gudlaugsson, Eythor; Patton, Henry

    2016-05-01

    Variations in the flow of ice streams and outlet glaciers are a primary control on ice sheet stability, yet comprehensive understanding of the key processes operating at the ice-bed interface remains elusive. Basal resistance is critical, especially sticky spots--localized zones of high basal traction--for maintaining force balance in an otherwise well-lubricated/high-slip subglacial environment. Here we consider the influence of subglacial gas-hydrate formation on ice stream dynamics, and its potential to initiate and maintain sticky spots. Geophysical data document the geologic footprint of a major palaeo-ice-stream that drained the Barents Sea-Fennoscandian ice sheet approximately 20,000 years ago. Our results reveal a ~250 km2 sticky spot that coincided with subsurface shallow gas accumulations, seafloor fluid expulsion and a fault complex associated with deep hydrocarbon reservoirs. We propose that gas migrating from these reservoirs formed hydrates under high-pressure, low-temperature subglacial conditions. The gas hydrate desiccated, stiffened and thereby strengthened the subglacial sediments, promoting high traction--a sticky spot--that regulated ice stream flow. Deep hydrocarbon reservoirs are common beneath past and contemporary glaciated areas, implying that gas-hydrate regulation of subglacial dynamics could be a widespread phenomenon.

  2. [Regulation of neurogenesis: factors affecting of new neurons formation in adult mammals brain].

    Science.gov (United States)

    Respondek, Michalina; Buszman, Ewa

    2015-01-01

    Neurogenesis is a complex and multi-step process of generating completely functional neurons. This process in adult brain is based on pluripotentional neuronal stem cells (NSC), which are able to proliferation and differentiation into mature neurons or glial cells. NSC are located in subgranular zone inside hippocampus and in subventricular zone. The new neurons formation depends on many endo- and exogenous factors which modulate each step of neurogenesis. This article describes the most important regulators of adult neurogenesis, mainly: neurotrophins, growth factors, hormones, neurotransmitters and microenvironment of NSC. Some drugs, especially antipsychotics, antidepressants and normothymics may affect the neurogenic properties of adult brain. Moreover pathological processes such as neuroinflammation, stroke or epilepsy are able to induce proliferation of NSC. The proneurogenic effects of psychotropic drugs and pathological processes are associated with their ability to increase some hormones and neurotrophins level, as well as with rising the expression of antiapoptotic Bcl-2 protein and metalloproteinase MMP-2. Additionaly, some drugs, for example haloperidol, are able to block prolactin and dopaminergic neuroblasts receptors. Down-regulation of adult neurogenesis is associated with alcohol abuse and high stress level. Negative effect of many drugs, such as cytostatics, COX-2 inhibitors and opioides was also observed. The proneurogenic effect of described factors suggest their broad therapeutic potential and gives a new perspective on an effective and modern treatment of many neuropsychiatric disorders. This effect can also help to clarify the pathogenesis of disorders associated with proliferation and degeneration of adult brain cells. PMID:27259217

  3. Sensory Cortical Plasticity Participates in the Epigenetic Regulation of Robust Memory Formation

    Directory of Open Access Journals (Sweden)

    Mimi L. Phan

    2016-01-01

    Full Text Available Neuroplasticity remodels sensory cortex across the lifespan. A function of adult sensory cortical plasticity may be capturing available information during perception for memory formation. The degree of experience-dependent remodeling in sensory cortex appears to determine memory strength and specificity for important sensory signals. A key open question is how plasticity is engaged to induce different degrees of sensory cortical remodeling. Neural plasticity for long-term memory requires the expression of genes underlying stable changes in neuronal function, structure, connectivity, and, ultimately, behavior. Lasting changes in transcriptional activity may depend on epigenetic mechanisms; some of the best studied in behavioral neuroscience are DNA methylation and histone acetylation and deacetylation, which, respectively, promote and repress gene expression. One purpose of this review is to propose epigenetic regulation of sensory cortical remodeling as a mechanism enabling the transformation of significant information from experiences into content-rich memories of those experiences. Recent evidence suggests how epigenetic mechanisms regulate highly specific reorganization of sensory cortical representations that establish a widespread network for memory. Thus, epigenetic mechanisms could initiate events to establish exceptionally persistent and robust memories at a systems-wide level by engaging sensory cortical plasticity for gating what and how much information becomes encoded.

  4. Flat leaf formation realized by cell-division control and mutual recessive gene regulation.

    Science.gov (United States)

    Hayakawa, Yoshinori; Tachikawa, Masashi; Mochizuki, Atsushi

    2016-09-01

    Most of the land plants generally have dorsoventrally flat leaves, maximizing the surface area of both upper (adaxial) side and lower (abaxial) side. The former is specialized for light capturing for photosynthesis and the latter is specialized for gas exchange. From findings of molecular genetics, it has been considered that the coupled dynamics between tissue morphogenesis and gene regulation for cell identity is responsible for making flat leaves. The hypothesis claims that a flat leaf is generated under two assumptions, (i) two mutually recessive groups of genes specify adaxial and abaxial sides of a leaf, (ii) cell divisions are induced at the limited region in the leaf margin where both of two groups are expressed. We examined the plausibility and possibility of this hypothesis from the dynamical point of view. We studied a mathematical model where two processes are coupled, tissue morphogenesis induced by cell division and deformation, and dynamics of gene regulations. From the analysis of the model we found that the classically believed hypothesis is not sufficient to generate flat leaves with high probability. We examined several different modifications and revision of the model. Then we found that a simple additional rule of polarized cell division facilitates flat leaf formation. The result of our analysis gives prediction of possible mechanism, which can be easily verified in experiments. PMID:27287339

  5. Pyk2 regulates megakaryocyte-induced increases in osteoblast number and bone formation.

    Science.gov (United States)

    Cheng, Ying-Hua; Hooker, R Adam; Nguyen, Khanh; Gerard-O'Riley, Rita; Waning, David L; Chitteti, Brahmananda R; Meijome, Tomas E; Chua, Hui Lin; Plett, Artur P; Orschell, Christie M; Srour, Edward F; Mayo, Lindsey D; Pavalko, Fredrick M; Bruzzaniti, Angela; Kacena, Melissa A

    2013-06-01

    Preclinical and clinical evidence from megakaryocyte (MK)-related diseases suggests that MKs play a significant role in maintaining bone homeostasis. Findings from our laboratories reveal that MKs significantly increase osteoblast (OB) number through direct MK-OB contact and the activation of integrins. We, therefore, examined the role of Pyk2, a tyrosine kinase known to be regulated downstream of integrins, in the MK-mediated enhancement of OBs. When OBs were co-cultured with MKs, total Pyk2 levels in OBs were significantly enhanced primarily because of increased Pyk2 gene transcription. Additionally, p53 and Mdm2 were both decreased in OBs upon MK stimulation, which would be permissive of cell cycle entry. We then demonstrated that OB number was markedly reduced when Pyk2-/- OBs, as opposed to wild-type (WT) OBs, were co-cultured with MKs. We also determined that MKs inhibit OB differentiation in the presence and absence of Pyk2 expression. Finally, given that MK-replete spleen cells from GATA-1-deficient mice can robustly stimulate OB proliferation and bone formation in WT mice, we adoptively transferred spleen cells from these mice into Pyk2-/- recipient mice. Importantly, GATA-1-deficient spleen cells failed to stimulate an increase in bone formation in Pyk2-/- mice, suggesting in vivo the important role of Pyk2 in the MK-induced increase in bone volume. Further understanding of the signaling pathways involved in the MK-mediated enhancement of OB number and bone formation will facilitate the development of novel anabolic therapies to treat bone loss diseases. PMID:23362087

  6. PPAR-γ activation by Tityus serrulatus venom regulates lipid body formation and lipid mediator production.

    Science.gov (United States)

    Zoccal, Karina Furlani; Paula-Silva, Francisco Wanderley Garcia; Bitencourt, Claudia da Silva; Sorgi, Carlos Artério; Bordon, Karla de Castro Figueiredo; Arantes, Eliane Candiani; Faccioli, Lúcia Helena

    2015-01-01

    Tityus serrulatus venom (TsV) consists of numerous peptides with different physiological and pharmacological activities. Studies have shown that scorpion venom increases pro-inflammatory cytokine production, contributing to immunological imbalance, multiple organ dysfunction, and patient death. We have previously demonstrated that TsV is a venom-associated molecular pattern (VAMP) recognized by TLRs inducing intense inflammatory reaction through the production of pro-inflammatory cytokines and arachidonic acid-derived lipid mediators prostaglandin (PG)E2 and leukotriene (LT)B4. Lipid bodies (LBs) are potential sites for eicosanoid production by inflammatory cells. Moreover, recent studies have shown that the peroxisome proliferator-activated receptor gamma (PPAR-γ) is implicated in LB formation and acts as an important modulator of lipid metabolism during inflammation. In this study, we used murine macrophages to evaluate whether the LB formation induced by TsV after TLR recognition correlates with lipid mediator generation by macrophages and if it occurs through PPAR-γ activation. We demonstrate that TsV acts through TLR2 and TLR4 stimulation and PPAR-γ activation to induce LB formation and generation of PGE2 and LTB4. Our data also show that PPAR-γ negatively regulates the pro-inflammatory NF-κB transcription factor. Based on these results, we suggest that during envenomation, LBs constitute functional organelles for lipid mediator production through signaling pathways that depend on cell surface and nuclear receptors. These findings point to the inflammatory mechanisms that might also be triggered during human envenomation by TsV. PMID:25450800

  7. Non-Cooperative Exercise Boundaries and Regulation under Uncertainty: The Case of Cost-Reducing R&D

    OpenAIRE

    Anastasios Xepapadeas

    2001-01-01

    This paper extends the concept of the exercise boundary as an analytical tool in determining when an optimizing agent might undertake an irreversible action under uncertainty. to situations where the objective function of optimizing agents depends on decisions taken by other agents. By using the case of cost redusing R&D in a fixed numbers oligopoly under demand and technological uncertainty, the exercise bounadaries and the corresponding optimal R&D accumulation paths are determined fot the ...

  8. Wdr18 is required for Kupffer's vesicle formation and regulation of body asymmetry in zebrafish.

    Directory of Open Access Journals (Sweden)

    Wei Gao

    Full Text Available Correct specification of the left-right (L-R axis is important for organ morphogenesis. Conserved mechanisms involving cilia rotation inside node-like structures and asymmetric Nodal signaling in the lateral plate mesoderm (LPM, which are important symmetry-breaking events, have been intensively studied. In zebrafish, the clustering and migration of dorsal forerunner cells (DFCs is critical for the formation of the Kuppfer's vesicle (KV. However, molecular events underlying DFC clustering and migration are less understood. The WD-repeat proteins function in a variety of biological processes, including cytoskeleton assembly, intracellular trafficking, mRNA splicing, transcriptional regulation and cell migration. However, little is known about the function of WD-repeat proteins in L-R asymmetry determination. Here, we report the identification and functional analyses of zebrafish wdr18, a novel gene that encodes a WD-repeat protein that is highly conserved among vertebrate species. wdr18 was identified from a Tol2 transposon-mediated enhancer trap screen. Follow-up analysis of wdr18 mRNA expression showed that it was detected in DFCs or the KV progenitor cells and later in the KV at early somitogenesis stages. Morpholino knockdown of wdr18 resulted in laterality defects in the visceral organs, which were preceded by the mis-expression of Nodal-related genes, including spaw and pitx2. Examination of morphants at earlier stages revealed that the KV had fewer and shorter cilia which are immotile and a smaller cavity. We further investigated the organization of DFCs in wdr18 morphant embryos using ntl and sox17 as specific markers and found that the clustering and migration of DFC was altered, leading to a disorganized KV. Finally, through a combination of wdr18 and itgb1b morpholino injections, we provided evidence that wdr18 and itgb1b genetically interact in the laterality determination process. Thus, we reveal a new and essential role for WD

  9. Iodine-mediated coastal particle formation: an overview of the Reactive Halogens in the Marine Boundary Layer (RHaMBLe Roscoff coastal study

    Directory of Open Access Journals (Sweden)

    G. McFiggans

    2010-03-01

    Full Text Available This paper presents a summary of the measurements made during the heavily-instrumented Reactive Halogens in the Marine Boundary Layer (RHaMBLe coastal study in Roscoff on the North West coast of France throughout September 2006. It was clearly demonstrated that iodine-mediated coastal particle formation occurs, driven by daytime low tide emission of molecular iodine, I2, by macroalgal species fully or partially exposed by the receding waterline. Ultrafine particle concentrations strongly correlate with the rapidly recycled reactive iodine species, IO, produced at high concentrations following photolysis of I2. The heterogeneous macroalgal I2 sources lead to variable relative concentrations of iodine species observed by path-integrated and in situ measurement techniques.

    Apparent particle emission fluxes were associated with an enhanced apparent depositional flux of ozone, consistent with both a direct O3 deposition to macroalgae and involvement of O3 in iodine photochemistry and subsequent particle formation below the measurement height. The magnitude of the particle formation events was observed to be greatest at the lowest tides with the highest concentrations of ultrafine particles growing to the largest sizes, probably by the condensation of anthropogenically-formed condensable material. At such sizes the particles should be able to act as cloud condensation nuclei at reasonable atmospheric supersaturations.

  10. Iodine-mediated coastal particle formation: an overview of the Reactive Halogens in the Marine Boundary Layer (RHaMBLe Roscoff coastal study

    Directory of Open Access Journals (Sweden)

    G. McFiggans

    2009-12-01

    Full Text Available This paper presents a summary of the measurements that were made during the heavily-instrumented Reactive Halogens in the Marine Boundary Layer (RHaMBLe coastal study in Roscoff on the North West coast of France. It was clearly demonstrated that iodine-mediated coastal particle formation occurs, driven by daytime low tide emission of molecular iodine, I2, by macroalgal species fully or partially exposed by the receding waterline. Ultrafine particle concentrations strongly correlate with the rapidly recycled reactive iodine species, IO, produced at high concentrations following photolysis of I2. The heterogeneous macroalgal I2 sources lead to variable relative concentrations of iodine species observed by path-integrated and in situ measurement techniques.

    Apparent particle emission fluxes were associated with an enhanced apparent depositional flux of ozone, consistent with both a direct O3 deposition to macroalgae and involvement of O3 in iodine photochemistry and subsequent particle formation below the measurement height. The magnitude of the particle formation events was observed to be greatest at the lowest tides with higher concentrations of ultrafine particles growing to much larger sizes, probably by the condensation of anthropogenically-formed condensable material. At such sizes the particles should be able to act as cloud condensation nuclei at reasonable atmospheric supersaturations.

  11. REGULATION OF STAR FORMATION RATES IN MULTIPHASE GALACTIC DISKS: A THERMAL/DYNAMICAL EQUILIBRIUM MODEL

    International Nuclear Information System (INIS)

    We develop a model for the regulation of galactic star formation rates ΣSFR in disk galaxies, in which interstellar medium (ISM) heating by stellar UV plays a key role. By requiring that thermal and (vertical) dynamical equilibrium are simultaneously satisfied within the diffuse gas, and that stars form at a rate proportional to the mass of the self-gravitating component, we obtain a prediction for ΣSFR as a function of the total gaseous surface density Σ and the midplane density of stars+dark matter ρsd. The physical basis of this relationship is that the thermal pressure in the diffuse ISM, which is proportional to the UV heating rate and therefore to ΣSFR, must adjust until it matches the midplane pressure value set by the vertical gravitational field. Our model applies to regions where Σ ∼sun pc-2. In low-ΣSFR (outer-galaxy) regions where diffuse gas dominates, the theory predicts that ΣSFR∝Σ√(ρsd). The decrease of thermal equilibrium pressure when ΣSFR is low implies, consistent with observations, that star formation can extend (with declining efficiency) to large radii in galaxies, rather than having a sharp cutoff at a fixed value of Σ. The main parameters entering our model are the ratio of thermal pressure to total pressure in the diffuse ISM, the fraction of diffuse gas that is in the warm phase, and the star formation timescale in self-gravitating clouds; all of these are (at least in principle) direct observables. At low surface density, our model depends on the ratio of the mean midplane FUV intensity (or thermal pressure in the diffuse gas) to the star formation rate, which we set based on solar-neighborhood values. We compare our results to recent observations, showing good agreement overall for azimuthally averaged data in a set of spiral galaxies. For the large flocculent spiral galaxies NGC 7331 and NGC 5055, the correspondence between theory and observation is remarkably close.

  12. Tissue growth controlled by geometric boundary conditions: a simple model recapitulating aspects of callus formation and bone healing.

    Science.gov (United States)

    Fischer, F Dieter; Zickler, Gerald A; Dunlop, John W C; Fratzl, Peter

    2015-06-01

    The shape of tissues arises from a subtle interplay between biochemical driving forces, leading to cell growth, division and extracellular matrix formation, and the physical constraints of the surrounding environment, giving rise to mechanical signals for the cells. Despite the inherent complexity of such systems, much can still be learnt by treating tissues that constantly remodel as simple fluids. In this approach, remodelling relaxes all internal stresses except for the pressure which is counterbalanced by the surface stress. Our model is used to investigate how wettable substrates influence the stability of tissue nodules. It turns out for a growing tissue nodule in free space, the model predicts only two states: either the tissue shrinks and disappears, or it keeps growing indefinitely. However, as soon as the tissue wets a substrate, stable equilibrium configurations become possible. Furthermore, by investigating more complex substrate geometries, such as tissue growing at the end of a hollow cylinder, we see features reminiscent of healing processes in long bones, such as the existence of a critical gap size above which healing does not occur. Despite its simplicity, the model may be useful in describing various aspects related to tissue growth, including biofilm formation and cancer metastases. PMID:26018964

  13. The anatomy of a star-forming galaxy: Pressure-driven regulation of star formation in simulated galaxies

    CERN Document Server

    Benincasa, S M; Couchman, H M P; Keller, B W

    2016-01-01

    We explore the regulation of star formation in star-forming galaxies through a suite of high-resolution isolated galaxy simulations. We use the SPH code GASOLINE, including photoelectric heating and metal cooling, which produces a multi-phase interstellar medium. We show that representative star formation and feedback sub-grid models naturally lead to a weak, sub-linear dependence between the amount of star formation and changes to star formation parameters. We incorporate these sub-grid models into an equilibrium pressure-driven regulation framework. We show that the sub-linear scaling arises as a consequence of the non-linear relationship between scale height and the effective pressure generated by stellar feedback. Thus, simulated star-formation regulation is sensitive to how well vertical structure in the ISM is resolved. Full galaxy disks experience density waves which drive locally time-dependent star formation. We develop a simple time-dependent, pressure-driven model that reproduces the response extre...

  14. Natural mutations in a Staphylococcus aureus virulence regulator attenuate cytotoxicity but permit bacteremia and abscess formation.

    Science.gov (United States)

    Das, Sudip; Lindemann, Claudia; Young, Bernadette C; Muller, Julius; Österreich, Babett; Ternette, Nicola; Winkler, Ann-Cathrin; Paprotka, Kerstin; Reinhardt, Richard; Förstner, Konrad U; Allen, Elizabeth; Flaxman, Amy; Yamaguchi, Yuko; Rollier, Christine S; van Diemen, Pauline; Blättner, Sebastian; Remmele, Christian W; Selle, Martina; Dittrich, Marcus; Müller, Tobias; Vogel, Jörg; Ohlsen, Knut; Crook, Derrick W; Massey, Ruth; Wilson, Daniel J; Rudel, Thomas; Wyllie, David H; Fraunholz, Martin J

    2016-05-31

    Staphylococcus aureus is a major bacterial pathogen, which causes severe blood and tissue infections that frequently emerge by autoinfection with asymptomatically carried nose and skin populations. However, recent studies report that bloodstream isolates differ systematically from those found in the nose and skin, exhibiting reduced toxicity toward leukocytes. In two patients, an attenuated toxicity bloodstream infection evolved from an asymptomatically carried high-toxicity nasal strain by loss-of-function mutations in the gene encoding the transcription factor repressor of surface proteins (rsp). Here, we report that rsp knockout mutants lead to global transcriptional and proteomic reprofiling, and they exhibit the greatest signal in a genome-wide screen for genes influencing S. aureus survival in human cells. This effect is likely to be mediated in part via SSR42, a long-noncoding RNA. We show that rsp controls SSR42 expression, is induced by hydrogen peroxide, and is required for normal cytotoxicity and hemolytic activity. Rsp inactivation in laboratory- and bacteremia-derived mutants attenuates toxin production, but up-regulates other immune subversion proteins and reduces lethality during experimental infection. Crucially, inactivation of rsp preserves bacterial dissemination, because it affects neither formation of deep abscesses in mice nor survival in human blood. Thus, we have identified a spontaneously evolving, attenuated-cytotoxicity, nonhemolytic S. aureus phenotype, controlled by a pleiotropic transcriptional regulator/noncoding RNA virulence regulatory system, capable of causing S. aureus bloodstream infections. Such a phenotype could promote deep infection with limited early clinical manifestations, raising concerns that bacterial evolution within the human body may contribute to severe infection. PMID:27185949

  15. The Enterococcus faecium enterococcal biofilm regulator, EbrB, regulates the esp operon and is implicated in biofilm formation and intestinal colonization.

    Directory of Open Access Journals (Sweden)

    Janetta Top

    Full Text Available Nowadays, Enterococcus faecium is one of the leading nosocomial pathogens worldwide. Strains causing clinical infections or hospital outbreaks are enriched in the enterococcal surface protein (Esp encoding ICEEfm1 mobile genetic element. Previous studies showed that Esp is involved in biofilm formation, endocarditis and urinary tract infections. In this study, we characterized the role of the putative AraC type of regulator (locus tag EfmE1162_2351, which we renamed ebrB and which is, based on the currently available whole genome sequences, always located upstream of the esp gene, and studied its role in Esp surface exposure during growth. A markerless deletion mutant of ebrB resulted in reduced esp expression and complete abolishment of Esp surface exposure, while Esp cell-surface exposure was restored when this mutant was complemented with an intact copy of ebrB. This demonstrates a role for EbrB in esp expression. However, during growth, ebrB expression levels did not change over time, while an increase in esp expression at both RNA and protein level was observed during mid-log and late-log phase. These results indicate the existence of a secondary regulation system for esp, which might be an unknown quorum sensing system as the enhanced esp expression seems to be cell density dependent. Furthermore, we determined that esp is part of an operon of at least 3 genes putatively involved in biofilm formation. A semi-static biofilm model revealed reduced biofilm formation for the EbrB deficient mutant, while dynamics of biofilm formation using a flow cell system revealed delayed biofilm formation in the ebrB mutant. In a mouse intestinal colonization model the ebrB mutant was less able to colonize the gut compared to wild-type strain, especially in the small intestine. These data indicate that EbrB positively regulates the esp operon and is implicated in biofilm formation and intestinal colonization.

  16. Extreme frazil and bottom ice formation causing ice problems in a regulated river

    International Nuclear Information System (INIS)

    The waterflow of the Otta River in Norway is regulated for electric power generation. Water discharge is usually increased during winter causing extreme frazil and bottom ice formation in the river. Extreme frazil production can be followed by an increased water stage in the river, causing an increased ground water stage and flooding of basements and sewage systems in the town of Otta. Ice runs have been known to further aggravate the situation. The frazil accumulates in the Otta tributary and also in the main river Lagen. Weather conditions, discharge in the river, and river bed geography are the three main parameters which influence the ice conditions in the area. Reducing the discharge is the best way to address the problem. Knowledge of weather conditions and accurate weather forecasts are important in determining when to start reducing the discharge. The natural and man-made changes to the river bed topography also have an influence on ice conditions, particularly the capacity for transporting frazil down the river. 3 figs

  17. Clumpy high-z galaxies as a testbed for feedback-regulated galaxy formation

    CERN Document Server

    Mayer, Lucio; Lupi, Alessandro; Keller, Ben; Wadsley, James; Madau, Piero

    2016-01-01

    We study the dependence of fragmentation in massive gas-rich galaxy disks at $z > 1$ on feedback model and hydrodynamical method, employing the GASOLINE2 SPH code and the lagrangian mesh-less code GIZMO in finite mass mode. We compare non-cosmological galaxy disk runs with standard blastwave supernovae (SN)feedback, which introduces delayed cooling in order to drive winds, and runs with the new superbubble SN feedback, which produces winds naturally by modelling the detailed physics of SN-driven bubbles and leads to efficient self-regulation of star formation. We find that, with blastwave feedback, massive star forming clumps form in comparable number and with very similar masses in GASOLINE2 and GIZMO. The typical masses are in the range $10^7-10^8 M_{\\odot}$, lower than in most previous works, while giant clumps with masses above $10^9 M_{\\odot}$ are exceedingly rare. With superbubble feedback, instead, massive bound star forming clumps do not form because galaxies never undergo a phase of violent disk inst...

  18. The SILCC project: III. Regulation of star formation and outflows by stellar winds and supernovae

    CERN Document Server

    Gatto, A; Naab, T; Girichidis, P; Wünsch, R; Glover, S C O; Klessen, R S; Clark, P C; Peters, T; Derigs, D; Baczynski, C; Puls, J

    2016-01-01

    We study the impact of stellar winds and supernovae on the multi-phase interstellar medium using three-dimensional hydrodynamical simulations carried out with FLASH. The selected galactic disc region has a size of (500 pc)$^2$ x $\\pm$ 5 kpc and a gas surface density of 10 M$_{\\odot}$/pc$^2$. The simulations include an external stellar potential and gas self-gravity, radiative cooling and diffuse heating, sink particles representing star clusters, stellar winds from these clusters which combine the winds from indi- vidual massive stars by following their evolution tracks, and subsequent supernova explosions. Dust and gas (self-)shielding is followed to compute the chemical state of the gas with a chemical network. We find that stellar winds can regulate star (cluster) formation. Since the winds suppress the accretion of fresh gas soon after the cluster has formed, they lead to clusters which have lower average masses (10$^2$ - 10$^{4.3}$ M$_{\\odot}$) and form on shorter timescales (10$^{-3}$ - 10 Myr). In part...

  19. The role of Bni5 in the regulation of septin higher-order structure formation.

    Science.gov (United States)

    Patasi, Csilla; Godočíková, Jana; Michlíková, Soňa; Nie, Yan; Káčeriková, Radka; Kválová, Katarína; Raunser, Stefan; Farkašovský, Marian

    2015-12-01

    Septins are a family of conserved cytoskeletal proteins playing an essential role in cytokinesis and in many other cellular processes in fungi and animals. In budding yeast Saccharomyces cerevisiae, septins form filaments and higher-order structures at the mother-bud neck depending on the particular stage of the cell cycle. Septin structures at the division plane serve as a scaffold to recruit the proteins required for particular cellular processes. The formation and localization of septin structures at particular stages of the cell cycle also determine functionality of these proteins. Many different proteins participate in regulating septin assembly. Despite recent developments, we are only beginning to understand how specific protein-protein interactions lead to changes in the polymerization of septin filaments or assembly of higher-order structures. Here, using fluorescence and electron microscopy, we found that Bni5 crosslinks septin filaments into networks by bridging pairs or multiple filaments, forming structures that resemble railways. Furthermore, Bni5 appears to be a substrate of the Elm1 protein kinase in vitro. Moreover, Elm1 induces in the presence of Bni5 disassembly of long septin filaments, suggesting that these proteins may participate in the hourglass to double ring transition. This work gives new insight into the regulatory role of Bni5 in the structural changes of septins. PMID:26351911

  20. The mediator complex subunit Med10 regulates heart valve formation in zebrafish by controlling Tbx2b-mediated Has2 expression and cardiac jelly formation.

    Science.gov (United States)

    Just, Steffen; Hirth, Sofia; Berger, Ina M; Fishman, Mark C; Rottbauer, Wolfgang

    2016-09-01

    In search for novel key regulators of cardiac valve formation, we isolated the zebrafish cardiac valve mutant ping pong (png). We find that an insertional promoter mutation within the zebrafish mediator complex subunit 10 (med10) gene is leading to impaired heart valve formation. Expression of the T-box transcription factor 2b (Tbx2b), known to be essential in cardiac valve development, is severely reduced in png mutant hearts. We demonstrate here that transient reconstitution of Tbx2b expression rescues AV canal development in png mutant zebrafish. By contrast, overexpression of Forkhead box N4 (Foxn4), a known upstream regulator of Tbx2b, is not capable to reconstitute tbx2b expression and heart valve formation in Med10-deficient png mutant hearts. Interestingly, hyaluronan synthase 2 (has2), a known downstream target of Tbx2 and producer of hyaluronan (HA) - a major ECM component of the cardiac jelly and critical for proper heart valve development - is completely absent in ping pong mutant hearts. We propose here a rather unique role of Med10 in orchestrating cardiac valve formation by mediating Foxn4 dependent tbx2b transcription, expression of Has2 and subsequently proper development of the cardiac jelly. PMID:27343557

  1. NMDA Receptor- and ERK-Dependent Histone Methylation Changes in the Lateral Amygdala Bidirectionally Regulate Fear Memory Formation

    Science.gov (United States)

    Gupta-Agarwal, Swati; Jarome, Timothy J.; Fernandez, Jordan; Lubin, Farah D.

    2014-01-01

    It is well established that fear memory formation requires de novo gene transcription in the amygdala. We provide evidence that epigenetic mechanisms in the form of histone lysine methylation in the lateral amygdala (LA) are regulated by NMDA receptor (NMDAR) signaling and involved in gene transcription changes necessary for fear memory…

  2. Differential regulation of c-di-GMP metabolic enzymes by environmental signals modulates biofilm formation in Yersinia pestis

    Directory of Open Access Journals (Sweden)

    Gai-Xian eRen

    2016-06-01

    Full Text Available Cyclic diguanylate (c-di-GMP is essential for Yersinia pestis biofilm formation, which is important for flea-borne blockage-dependent plague transmission. Two diguanylate cyclases (DGCs, HmsT and HmsD and one phosphodiesterase (PDE, HmsP are responsible for the synthesis and degradation of c-di-GMP in Y. pestis. Here, we systematically analyzed the effect of various environmental signals on regulation of the biofilm phenotype, the c-di-GMP levels, and expression of HmsT, HmsD and HmsP in Y. pestis. Biofilm formation was higher in the presence of nonlethal high concentration of CaCl2, MgCl2, CuSO4, sucrose, sodium dodecyl sulfonate, or dithiothreitol, and was lower in the presence of FeCl2 or NaCl. In addition, we found that HmsD plays a major role in biofilm formation in acidic or redox environments. These environmental signals differentially regulated expression of HmsT, HmsP and HmsD, resulting in changes in the intracellular levels of c-di-GMP in Y. pestis. Our results suggest that bacteria can sense various environmental signals, and differentially regulates their DGCs and PDEs to coordinately regulate and adapt metabolism of c-di-GMP and biofilm formation to changing environments.

  3. The Ubiquitin-Specific Protease 14 (USP14) Is a Critical Regulator of Long-Term Memory Formation

    Science.gov (United States)

    Jarome, Timothy J.; Kwapis, Janine L.; Hallengren, Jada J.; Wilson, Scott M.; Helmstetter, Fred J.

    2014-01-01

    Numerous studies have suggested a role for ubiquitin-proteasome-mediated protein degradation in learning-dependent synaptic plasticity; however, very little is known about how protein degradation is regulated at the level of the proteasome during memory formation. The ubiquitin-specific protease 14 (USP14) is a proteasomal deubiquitinating enzyme…

  4. Nuclear translocation of phosphorylated STAT3 regulates VEGF-A-induced lymphatic endothelial cell migration and tube formation

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, Hideki; Tokumaru, Sho; Hanakawa, Yasushi; Shiraishi, Ken; Shirakata, Yuji; Dai, Xiuju; Yang, Lijun; Tohyama, Mikiko; Hashimoto, Koji [Department of Dermatology, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295 (Japan); Sayama, Koji, E-mail: sayama@m.ehime-u.ac.jp [Department of Dermatology, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295 (Japan)

    2011-09-02

    Highlights: {yields} VEGF-A enhanced lymphatic endothelial cell migration and increased tube formation. {yields} VEGF-A treated lymphatic endothelial cell showed activation of STAT3. {yields} Dominant-negative STAT3 inhibited VEGF-A-induced lymphatic endothelial cell migration and tube formation. -- Abstract: Vascular endothelial growth factor (VEGF) is an endothelial cell-specific growth factor that regulates endothelial functions, and signal transducers and activators of transcription (STATs) are known to be important during VEGF receptor signaling. The aim of this study was to determine whether STAT3 regulates VEGF-induced lymphatic endothelial cell (LEC) migration and tube formation. VEGF-A (33 ng/ml) enhanced LEC migration by 2-fold and increased tube length by 25% compared with the control, as analyzed using a Boyden chamber and Matrigel assay, respectively. Western blot analysis and immunostaining revealed that VEGF-A induced the nuclear translocation of phosphorylated STAT3 in LECs, and this translocation was blocked by the transfection of LECs with an adenovirus vector expressing a dominant-negative mutant of STAT3 (Ax-STAT3F). Transfection with Ax-STAT3F also almost completely inhibited VEGF-A-induced LEC migration and tube formation. These results indicate that STAT3 is essential for VEGF-A-induced LEC migration and tube formation and that STAT3 regulates LEC functions.

  5. A Nitric Oxide-Responsive Quorum Sensing Circuit in Vibrio harveyi Regulates Flagella Production and Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Yueming Xu

    2013-08-01

    Full Text Available Cell signaling plays an important role in the survival of bacterial colonies. They use small molecules to coordinate gene expression in a cell density dependent manner. This process, known as quorum sensing, helps bacteria regulate diverse functions such as bioluminescence, biofilm formation and virulence. In Vibrio harveyi, a bioluminescent marine bacterium, four parallel quorum-sensing systems have been identified to regulate light production. We have previously reported that nitric oxide (NO, through the H-NOX/HqsK quorum sensing pathway contributes to light production in V. harveyi through the LuxU/LuxO/LuxR quorum sensing pathway. In this study, we show that nitric oxide (NO also regulates flagellar production and enhances biofilm formation. Our data suggest that V. harveyi is capable of switching between lifestyles to be able to adapt to changes in the environment.

  6. A nitric oxide-responsive quorum sensing circuit in Vibrio harveyi regulates flagella production and biofilm formation.

    Science.gov (United States)

    Henares, Bernadette M; Xu, Yueming; Boon, Elizabeth M

    2013-01-01

    Cell signaling plays an important role in the survival of bacterial colonies. They use small molecules to coordinate gene expression in a cell density dependent manner. This process, known as quorum sensing, helps bacteria regulate diverse functions such as bioluminescence, biofilm formation and virulence. In Vibrio harveyi, a bioluminescent marine bacterium, four parallel quorum-sensing systems have been identified to regulate light production. We have previously reported that nitric oxide (NO), through the H-NOX/HqsK quorum sensing pathway contributes to light production in V. harveyi through the LuxU/LuxO/LuxR quorum sensing pathway. In this study, we show that nitric oxide (NO) also regulates flagellar production and enhances biofilm formation. Our data suggest that V. harveyi is capable of switching between lifestyles to be able to adapt to changes in the environment. PMID:23965964

  7. Role of Ordering Energy in Formation of Grain Structure and Special Boundaries Spectrum in OrderedAlloys with L12 Superstructure

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    It was revealed that an average energy of special boundaries is proportional to APB energy in the alloys with the L12 superstructure. This fact proves the appearance of the GAPBs in the planes of location of special boundaries in coincidence sites of ordered alloys. It was determined that the more energy of special boundaries in ordered alloys, the more energy of complex stacking fault. There is a correlation between the distribution of special boundaries as a function its relative energy and ordering energy: the more ordering energy, the more degree of washed away of distribution. The correlation between average relative energy of special boundaries and ordering energy was detected: the more ordering energy, the more average energy of special boundaries. The reverse dependence between ordering energy and average number of special boundaries in grains limited by boundaries of general type was discovered.

  8. Direct and indirect regulation of spinal cord Ia afferent terminal formation by the γ-Protocadherins

    Directory of Open Access Journals (Sweden)

    Tuhina ePrasad

    2011-12-01

    Full Text Available The Pcdh-γ gene cluster encodes 22 protocadherin adhesion molecules that interact as homophilic multimers and critically regulate synaptogenesis and apoptosis of interneurons in the developing spinal cord. Unlike interneurons, the two primary components of the monosynaptic stretch reflex circuit, dorsal root ganglion sensory neurons and ventral motor neurons, do not undergo excessive apoptosis in Pcdh-γdel/del null mutants, which die shortly after birth. However, as we show here, mutants exhibit severely disorganized Ia proprioceptive afferent terminals in the ventral horn. In contrast to the fine net-like pattern observed in wild-type mice, central Ia terminals in Pcdh-γ mutants are expanded, clumped, and fill the space between individual motor neurons; quantitative analysis shows a ~2.5 fold increase in the area of terminals. Concomitant with this, there is a 70% loss of the collaterals that Ia afferents extend to ventral interneurons, many of which undergo apoptosis in the mutants. The Ia afferent phenotype is ameliorated, though not entirely rescued, when apoptosis is blocked in Pcdh-γ null mice by introduction of a Bax null allele. This indicates that loss of ventral interneurons, which act as intermediate Ia afferent targets, contributes to the disorganization of terminals on motor pools. Restricted mutation of the Pcdh-γ cluster using conditional mutants and multiple Cre transgenic lines (Wnt1-Cre for sensory neurons; Pax2-Cre for ventral interneurons; Hb9-Cre for motor neurons also revealed a direct requirement for the γ-Pcdhs in Ia neurons and ventral interneurons, but not in motor neurons themselves. Together, these genetic manipulations indicate that the γ-Pcdhs are required for the formation of the Ia afferent circuit in two ways: First, they control the survival of ventral interneurons that act as intermediate Ia targets; and second, they provide a homophilic molecular cue between Ia afferents and target ventral interneurons.

  9. Developing young adolescents’ self-regulation by means of formative assessment: A theoretical perspective

    OpenAIRE

    Kelly D. Meusen-Beekman; Desirée Joosten-ten Brinke; Boshuizen, Henny P. A.

    2015-01-01

    Fostering self-regulated learning (SRL) has become increasingly important at various educational levels. Most studies on SRL have been conducted in higher education. The present literature study aims toward understanding self-regulation processes of students in primary and secondary education. We explored the development of young students’ self-regulation from a theoretical perspective. In addition, effective characteristics for an intervention to develop young students’ self-regulation were ...

  10. Influence of zinc dialkyldithiophosphate tribofilm formation on the tribological performance of self-mated diamond-like carbon contacts under boundary lubrication

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah Tasdemir, H., E-mail: habdullah46@gmail.com [Department of Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Tokoroyama, Takayuki; Kousaka, Hiroyuki; Umehara, Noritsugu [Department of Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Mabuchi, Yutaka [Nissan Motor Co. (Japan)

    2014-07-01

    Diamond-like carbon (DLC) coatings offer excellent mechanical and tribological properties that make them suitable protective coatings for various industrial applications. In recent years, several engine and power train components in passenger cars, which work under boundary lubricated conditions, have been coated with DLC coatings. Since conventional lubricants and lubricant additives are formulated for metal surfaces, there are still controversial questions concerning chemical reactivity between DLC surfaces and common lubricant additives owing to the chemical inertness of DLC coatings. In this work, we present the influence of zinc dialkyldithiophosphate (ZnDTP) anti-wear additives on the tribological performance of various self-mated DLC coatings under boundary lubrication conditions. The effects of hydrogen, doping elements, and surface morphology on the reactivity of DLC coatings to form a ZnDTP-derived tribofilm were investigated by atomic force microscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy. The results confirmed that ZnDTP-derived pad-like or patchy tribofilm forms on the surfaces depending on the DLC coating. It is seen that hydrogen content and doping elements increase pad-like tribofilm formation. Doped DLC coatings are found to give better wear resistance than non-doped DLC coatings. Furthermore, the addition of ZnDTP additives to the base oil significantly improves the wear resistance of hydrogenated DLC, silicon-doped hydrogenated DLC, and chromium-doped hydrogenated DLC. Hydrogen-free tetrahedral amorphous DLC coatings provide the lowest friction coefficient both in PAO (poly-alpha-olefin) and PAO + ZnDTP oils. - Highlights: • Zinc dialkyldithiophosphate (DTP) tribofilm formation on various DLC surfaces was evidenced. • Pad-like tribofilm was found on a-C:H, a-C, Si-DLC and Cr-DLC. • Pad-like tribofilm on DLC surfaces greatly increased the wear resistance. • Hydrogenated and doped DLC coatings are

  11. Influence of zinc dialkyldithiophosphate tribofilm formation on the tribological performance of self-mated diamond-like carbon contacts under boundary lubrication

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) coatings offer excellent mechanical and tribological properties that make them suitable protective coatings for various industrial applications. In recent years, several engine and power train components in passenger cars, which work under boundary lubricated conditions, have been coated with DLC coatings. Since conventional lubricants and lubricant additives are formulated for metal surfaces, there are still controversial questions concerning chemical reactivity between DLC surfaces and common lubricant additives owing to the chemical inertness of DLC coatings. In this work, we present the influence of zinc dialkyldithiophosphate (ZnDTP) anti-wear additives on the tribological performance of various self-mated DLC coatings under boundary lubrication conditions. The effects of hydrogen, doping elements, and surface morphology on the reactivity of DLC coatings to form a ZnDTP-derived tribofilm were investigated by atomic force microscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy. The results confirmed that ZnDTP-derived pad-like or patchy tribofilm forms on the surfaces depending on the DLC coating. It is seen that hydrogen content and doping elements increase pad-like tribofilm formation. Doped DLC coatings are found to give better wear resistance than non-doped DLC coatings. Furthermore, the addition of ZnDTP additives to the base oil significantly improves the wear resistance of hydrogenated DLC, silicon-doped hydrogenated DLC, and chromium-doped hydrogenated DLC. Hydrogen-free tetrahedral amorphous DLC coatings provide the lowest friction coefficient both in PAO (poly-alpha-olefin) and PAO + ZnDTP oils. - Highlights: • Zinc dialkyldithiophosphate (DTP) tribofilm formation on various DLC surfaces was evidenced. • Pad-like tribofilm was found on a-C:H, a-C, Si-DLC and Cr-DLC. • Pad-like tribofilm on DLC surfaces greatly increased the wear resistance. • Hydrogenated and doped DLC coatings are

  12. Genetic interaction of two abscisic acid signaling regulators, HY5 and FIERY1, in mediating lateral root formation

    KAUST Repository

    Chen, Hao

    2011-01-01

    Root architecture is continuously shaped in a manner that helps plants to better adapt to the environment. Gene regulation at the transcriptional or post-transcriptional levels largely controls this environmental response. Recently, RNA silencing has emerged as an important player in gene regulation and is involved in many aspects of plant development, including lateral root formation. In a recent study, we found that FIERY1, a bifunctional abiotic stress and abscisic acid (ABA) signaling regulator and an endogenous RNA silencing suppressor, mediates auxin response during lateral root formation in Arabidopsis. We proposed that FRY1 regulates lateral root development through its activity on adenosine 3,5-bisphosphate (PAP), a strong inhibitor of exoribonucleases (XRNs). Interestingly, some of the phenotypes of fry1, such as enhanced response to light in repressing hypocotyl elongation and hypersensitivity to ABA in lateral root growth, are opposite to those of another light- and ABA-signaling mutant, hy5. Here we analyzed the hy5 fry1 double mutant for root and hypocotyl growth. We found that the hy5 mutation can suppress the enhanced light sensitivity in fry1 hypocotyl elongation and restore the lateral root formation. The genetic interaction between HY5 and FRY1 indicates that HY5 and FRY1 may act in overlapping pathways that mediate light signaling and lateral root development. © 2011 Landes Bioscience.

  13. Regulation of ATP-dependent P-(Ser)-HPr formation in Streptococcus mutans and Streptococcus salivarius.

    Science.gov (United States)

    Thevenot, T; Brochu, D; Vadeboncoeur, C; Hamilton, I R

    1995-01-01

    Sugar transport via the phosphoenolpyruvate (PEP) phosphotransferase system involves PEP-dependent phosphorylation of the general phosphotransferase system protein, HPr, at histidine 15. However, gram-positive bacteria can also carry out ATP-dependent phosphorylation of HPr at serine 46 by means of (Ser)HPr kinase. In this study, we demonstrate that (Ser)HPr kinase in crude preparations of Streptococcus mutans Ingbritt and Streptococcus salivarius ATCC 25975 is membrane associated, with pH optima of 7.0 and 7.5, respectively. The latter organism possessed 7- to 27-fold-higher activity than S. mutans NCTC 10449, GS-5, and Ingbritt strains. The enzyme in S. salivarius was activated by fructose-1,6-bisphosphate (FBP) twofold with 0.05 mM ATP, but this intermediate was slightly inhibitory with 1.0 mM ATP at FBP concentrations up to 10 mM. Similar inhibition was observed with the enzyme from S. mutans Ingbritt. A variety of other glycolytic intermediates had no effect on kinase activity under these conditions. The activity and regulation of (Ser)HPr kinase were assessed in vivo by monitoring P-(Ser)-HPr formation in steady-state cells of S. mutans Ingbritt grown in continuous culture with limiting glucose (10 and 50 mM) and with excess glucose (100 and 200 mM). All four forms of HPr [free HPr, P approximately (His)-HPr, P-(Ser)-HPr, and P approximately (His)-P-(Ser)-HPr] could be detected in the cells; however, significant differences in the intracellular levels of the forms were apparent during growth at different glucose concentrations. The total HPr pool increased with increasing concentrations of glucose in the medium, with significant increases in the P-(Ser)-HPr and P approximately HHis)-P-(Ser)-HPr concentrations. For example, while total PEP-dependent phosphorylation [P approximately(His)-HPr plus P approximately (His)-P-(Ser)-HPr] varied only from 21.5 to 52.5 microgram mg of cell protein (-1) in cells grown at the four glucose concentrations, the total ATP

  14. Spatial Regulation of Gene Expression in Neurons During Synapse Formation and Synaptic Plasticity

    OpenAIRE

    Kim, Sangmok

    2013-01-01

    mRNA localization and regulated translation allow individual neurons to locally regulate the proteome of each of their many subcellular compartments. To investigate the spatial regulation of gene expression during synaptic plasticity, we used a translational reporter system to demonstrate synapse- and stimulus-specific translation during long-term facilitation of Aplysia sensory-motor synapse. These studies revealed a role for a retrograde signal from the postsynaptic motor neuron in regulati...

  15. Regulation of reactionary dentin formation by odontoblasts in response to polymicrobial invasion of dentin matrix

    OpenAIRE

    Charadram, Nattida; Farahani, Ramin M.; Harty, Derek; Rathsam, Catherine; Swain, Michael V.; Hunter, Neil

    2011-01-01

    Odontoblast synthesis of dentin proceeds through discrete but overlapping phases characterized by formation of a patterned organic matrix followed by remodelling and active mineralization. Microbial invasion of dentin in caries triggers an adaptive response by odontoblasts, culminating in formation of a structurally altered reactionary dentin, marked by biochemical and architectonic modifications including diminished tubularity. Scanning electron microscopy of the collagen framework in reacti...

  16. Retinyl Ester Formation by Lecithin:Retinol Acyltransferase Is a Key Regulator of Retinoid Homeostasis in Mouse Embryogenesis* s

    OpenAIRE

    Kim, Youn-Kyung; Wassef, Lesley; Hamberger, Leora; Piantedosi, Roseann; Palczewski, Krzysztof; Blaner, William S.; Quadro, Loredana

    2007-01-01

    The developing mammalian embryo is entirely dependent on the maternal circulation for its supply of retinoids (vitamin A and its metabolites). The mechanisms through which mammalian developing tissues maintain adequate retinoid levels in the face of suboptimal or excessive maternal dietary vitamin A intake have not been established. We investigated the role of retinyl ester formation catalyzed by lecithin:retinol acyltransferase (LRAT) in regulating retinoid homeostasis during embryogenesis. ...

  17. A Genome-wide RNAi Screen for Microtubule Bundle Formation and Lysosome Motility Regulation in Drosophila S2 Cells

    OpenAIRE

    Amber L. Jolly; Chi-Hao Luan; Brendon E. Dusel; Sara F. Dunne; Michael Winding; Vishrut J. Dixit; Chloe Robins; Jennifer L. Saluk; David J. Logan; Anne E. Carpenter; Manu Sharma; Deborah Dean; Andrew R. Cohen; Vladimir I. Gelfand

    2016-01-01

    Long-distance intracellular transport of organelles, mRNA, and proteins (“cargo”) occurs along the microtubule cytoskeleton by the action of kinesin and dynein motor proteins, but the vast network of factors involved in regulating intracellular cargo transport are still unknown. We capitalize on the Drosophila melanogaster S2 model cell system to monitor lysosome transport along microtubule bundles, which require enzymatically active kinesin-1 motor protein for their formation. We use an auto...

  18. A genome-wide RNAi screen for microtubule bundle formation and lysosome motility regulation in Drosophila S2 cells

    OpenAIRE

    Jolly, Amber L.; Luan, Chi-Hao; Dusel, Brendon E.; Dunne, Sara Fernandez; Winding, Michael; Dixit, Vishrut J.; Robins, Chloe; Saluk, Jennifer L.; Logan, David J.; Carpenter, Anne E.; Sharma, Manu; Dean, Deborah; Cohen, Andrew R.; Gelfand, Vladimir I.

    2016-01-01

    Long-distance intracellular transport of organelles, mRNA, and proteins (“cargo”) occurs along the microtubule cytoskeleton by the action of kinesin and dynein motor proteins; the vast network of factors involved in regulating intracellular cargo transport are still unknown. We capitalize on the Drosophila melanogaster S2 model cell system to monitor lysosome transport along microtubule bundles, which require enzymatically active kinesin-1 motor protein for their formation. We use an automate...

  19. Phosphorylation of K[superscript +] Channels at Single Residues Regulates Memory Formation

    Science.gov (United States)

    Vernon, Jeffrey; Irvine, Elaine E.; Peters, Marco; Jeyabalan, Jeshmi; Giese, K. Peter

    2016-01-01

    Phosphorylation is a ubiquitous post-translational modification of proteins, and a known physiological regulator of K[superscript +] channel function. Phosphorylation of K[superscript +] channels by kinases has long been presumed to regulate neuronal processing and behavior. Although circumstantial evidence has accumulated from behavioral studies…

  20. Developing Young Adolescents' Self-Regulation by Means of Formative Assessment: A Theoretical Perspective

    Science.gov (United States)

    Meusen-Beekman, Kelly D.; Joosten-ten Brinke, Desirée; Boshuizen, Henny P. A.

    2015-01-01

    Fostering self-regulated learning (SRL) has become increasingly important at various educational levels. Most studies on SRL have been conducted in higher education. The present literature study aims toward understanding self-regulation processes of students in primary and secondary education. We explored the development of young students'…

  1. The Sensor Kinase GacS Negatively Regulates Flagellar Formation and Motility in a Biocontrol Bacterium, Pseudomonas chlororaphis O6

    Directory of Open Access Journals (Sweden)

    Ji Soo Kim

    2014-06-01

    Full Text Available The GacS/GacA two component system regulates various traits related to the biocontrol potential of plant-associated pseudomonads. The role of the sensor kinase, GacS, differs between strains in regulation of motility. In this study, we determined how a gacS mutation changed cell morphology and motility in Pseudomonas chlororaphis O6. The gacS mutant cells were elongated in stationary-phase compared to the wild type and the complemented gacS mutant, but cells did not differ in length in logarithmic phase. The gacS mutant had a two-fold increase in the number of flagella compared with the wild type strain; flagella number was restored to that of the wild type in the complemented gacS mutant. The more highly flagellated gacS mutant cells had greater swimming motilities than that of the wild type strain. Enhanced flagella formation in the gacS mutant correlated with increased expression of three genes, fleQ, fliQ and flhF, involved in flagellar formation. Expression of these genes in the complemented gacS mutant was similar to that of the wild type. These findings show that this root-colonizing pseudomonad adjusts flagella formation and cell morphology in stationary-phase using GacS as a major regulator.

  2. GAS REGULATION OF GALAXIES: THE EVOLUTION OF THE COSMIC SPECIFIC STAR FORMATION RATE, THE METALLICITY-MASS-STAR-FORMATION RATE RELATION, AND THE STELLAR CONTENT OF HALOS

    Energy Technology Data Exchange (ETDEWEB)

    Lilly, Simon J.; Carollo, C. Marcella; Pipino, Antonio; Peng Yingjie [Institute for Astronomy, Department of Physics, ETH Zurich, CH-8093 Zurich (Switzerland); Renzini, Alvio [Department of Physics and Astronomy Galileo Galilei, Universita degli Studi di Padova, via Marzolo 8, I-35131 Padova (Italy)

    2013-08-01

    A very simple physical model of galaxies is one in which the formation of stars is instantaneously regulated by the mass of gas in a reservoir with mass loss scaling with the star-formation rate (SFR). This model links together three different aspects of the evolving galaxy population: (1) the cosmic time evolution of the specific star-formation rate (sSFR) relative to the growth of halos, (2) the gas-phase metallicities across the galaxy population and over cosmic time, and (3) the ratio of the stellar to dark matter mass of halos. The gas regulator is defined by the gas consumption timescale ({epsilon}{sup -1}) and the mass loading {lambda} of the wind outflow {lambda}{center_dot}SFR. The simplest regulator, in which {epsilon} and {lambda} are constant, sets the sSFR equal to exactly the specific accretion rate of the galaxy; more realistic situations lead to an sSFR that is perturbed from this precise relation. Because the gas consumption timescale is shorter than the timescale on which the system evolves, the metallicity Z is set primarily by the instantaneous operation of the regulator system rather than by the past history of the system. The metallicity of the gas reservoir depends on {epsilon}, {lambda}, and sSFR, and the regulator system therefore naturally produces a Z(m{sub star}, SFR) relation if {epsilon} and {lambda} depend on the stellar mass m{sub star}. Furthermore, this relation will be the same at all epochs unless the parameters {epsilon} and {lambda} themselves change with time. A so-called fundamental metallicity relation is naturally produced by these conditions. The overall mass-metallicity relation Z(m{sub star}) directly provides the fraction f{sub star}(m{sub star}) of incoming baryons that are being transformed into stars. The observed Z(m{sub star}) relation of Sloan Digital Sky Survey (SDSS) galaxies implies a strong dependence of stellar mass on halo mass that reconciles the different faint-end slopes of the stellar and halo mass

  3. Low-mass galaxy assembly in simulations: regulation of early star formation by radiation from massive stars

    CERN Document Server

    Trujillo-Gomez, Sebastian; Colin, Pedro; Ceverino, Daniel; Arraki, Kenza; Primack, Joel

    2013-01-01

    Despite recent success in forming realistic disc galaxies at redshift zero, simulations still form the bulk of their stars prematurely. We investigate the process of stellar mass assembly in low-mass simulated galaxies, a dwarf and a typical spiral, focusing on the effects of radiation from young stellar clusters. We employ a novel model of star formation in which stars form deterministically with a small efficiency per free-fall time, as observed in molecular clouds. Stellar feedback includes radiation pressure from massive stars and energy from supernova explosions and stellar winds. In galaxies with masses up to those of typical spirals, radiation efficiently suppresses star formation by dispersing and heating high density gas, mostly in the central regions, preventing the formation of a massive bulge. Once the galaxies reach this radiation-regulated growth regime, their global properties are robust to the specific choice of model parameters. Only when radiative feedback is included, do galaxies exhibit co...

  4. Multinuclear giant cell formation is enhanced by down-regulation of Wnt signaling in gastric cancer cell line, AGS

    International Nuclear Information System (INIS)

    AGS cells, which were derived from malignant gastric adenocarcinoma tissue, lack E-cadherin-mediated cell adhesion but have a high level of nuclear β-catenin, which suggests altered Wnt signal. In addition, approximately 5% of AGS cells form multinuclear giant cells in the routine culture conditions, while taxol treatment causes most AGS cells to become giant cells. The observation of reduced nuclear β-catenin levels in giant cells induced by taxol treatment prompted us to investigate the relationship between Wnt signaling and giant cell formation. After overnight serum starvation, the shape of AGS cells became flattened, and this morphological change was accompanied by decrease in Myc expression and an increase in the giant cell population. Lithium chloride treatment, which inhibits GSK3β activity, reversed these serum starvation effects, which suggests an inverse relationship between Wnt signaling and giant cell formation. Furthermore, the down-regulation of Wnt signaling caused by the over-expression of ICAT, E-cadherin, and Axin enhanced giant cell formation. Therefore, down-regulation of Wnt signaling may be related to giant cell formation, which is considered to be a survival mechanism against induced cell death

  5. In site bioimaging of hydrogen sulfide uncovers its pivotal role in regulating nitric oxide-induced lateral root formation.

    Directory of Open Access Journals (Sweden)

    Yan-Jun Li

    Full Text Available Hydrogen sulfide (H2S is an important gasotransmitter in mammals. Despite physiological changes induced by exogenous H2S donor NaHS to plants, whether and how H2S works as a true cellular signal in plants need to be examined. A self-developed specific fluorescent probe (WSP-1 was applied to track endogenous H2S in tomato (Solanum lycopersicum roots in site. Bioimaging combined with pharmacological and biochemical approaches were used to investigate the cross-talk among H2S, nitric oxide (NO, and Ca(2+ in regulating lateral root formation. Endogenous H2S accumulation was clearly associated with primordium initiation and lateral root emergence. NO donor SNP stimulated the generation of endogenous H2S and the expression of the gene coding for the enzyme responsible for endogenous H2S synthesis. Scavenging H2S or inhibiting H2S synthesis partially blocked SNP-induced lateral root formation and the expression of lateral root-related genes. The stimulatory effect of SNP on Ca(2+ accumulation and CaM1 (calmodulin 1 expression could be abolished by inhibiting H2S synthesis. Ca(2+ chelator or Ca(2+ channel blocker attenuated NaHS-induced lateral root formation. Our study confirmed the role of H2S as a cellular signal in plants being a mediator between NO and Ca(2+ in regulating lateral root formation.

  6. TCPs, WUSs, and WINDs: Families of transcription factors that regulate shoot meristem formation, stem cell maintenance, and somatic cell differentiation

    Directory of Open Access Journals (Sweden)

    Miho eIkeda

    2014-09-01

    Full Text Available In contrast to somatic mammalian cells, which cannot alter their fate, plant cells can dedifferentiate to form totipotent callus cells and regenerate a whole plant, following treatment with specific phytohormones. However, the regulatory mechanisms and key factors that control differentiation-dedifferentiation and cell totipotency have not been completely clarified in plants. Recently, several plant transcription factors that regulate meristem formation and dedifferentiation have been identified and include members of the TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP, WUSCHEL (WUS, and WOUND INDUCED DEDIFFERENTIATION (WIND1 families. WUS and WIND positively control plant cell totipotency, while TCP negatively controls it. Interestingly, TCP is a transcriptional activator that acts as a negative regulator of shoot meristem formation, and WUS is a transcriptional repressor that positively maintains totipotency of the stem cells of the shoot meristem. We describe here the functions of TCP, WUS and WIND transcription factors in the regulation of differentiation-dedifferentiation by positive and negative transcriptional regulators.

  7. Implementation of training programs in self-regulated learning strategies in Moodle format: results of a experience in higher education.

    Science.gov (United States)

    Núñez, José Carlos; Cerezo, Rebeca; Bernardo, Ana; Rosário, Pedro; Valle, Antonio; Fernández, Estrella; Suárez, Natalia

    2011-04-01

    This paper tests the efficacy of an intervention program in virtual format intended to train studying and self-regulation strategies in university students. The aim of this intervention is to promote a series of strategies which allow students to manage their learning processes in a more proficient and autonomous way. The program has been developed in Moodle format and hosted by the Virtual Campus of the University of Oviedo. The present study had a semi-experimental design, included an experimental group (n=167) and a control one (n=206), and used pretest and posttest measures (self-regulated learning strategies' declarative knowledge, self-regulated learning macro-strategy planning-execution-assessment, self-regulated learning strategies on text, surface and deep learning approaches, and academic achievement). Data suggest that the students enrolled in the training program, comparing with students in the control group, showed a significant improvement in their declarative knowledge, general and on text use of learning strategies, increased their deep approach to learning, decreased their use of a surface approach and, in what concerns to academic achievement, statistically significant differences have been found in favour of the experimental group. PMID:21504681

  8. GALAXY FORMATION WITH SELF-CONSISTENTLY MODELED STARS AND MASSIVE BLACK HOLES. I. FEEDBACK-REGULATED STAR FORMATION AND BLACK HOLE GROWTH

    International Nuclear Information System (INIS)

    There is mounting evidence for the coevolution of galaxies and their embedded massive black holes (MBHs) in a hierarchical structure formation paradigm. To tackle the nonlinear processes of galaxy-MBH interaction, we describe a self-consistent numerical framework which incorporates both galaxies and MBHs. The high-resolution adaptive mesh refinement (AMR) code Enzo is modified to model the formation and feedback of molecular clouds at their characteristic scale of 15.2 pc and the accretion of gas onto an MBH. Two major channels of MBH feedback, radiative feedback (X-ray photons followed through full three-dimensional adaptive ray tracing) and mechanical feedback (bipolar jets resolved in high-resolution AMR), are employed. We investigate the coevolution of a 9.2 x 1011 Msun galactic halo and its 105 Msun embedded MBH at redshift 3 in a cosmological ΛCDM simulation. The MBH feedback heats the surrounding interstellar medium (ISM) up to 106 K through photoionization and Compton heating and locally suppresses star formation in the galactic inner core. The feedback considerably changes the stellar distribution there. This new channel of feedback from a slowly growing MBH is particularly interesting because it is only locally dominant and does not require the heating of gas globally on the disk. The MBH also self-regulates its growth by keeping the surrounding ISM hot for an extended period of time.

  9. Galaxy Formation with Self-Consistently Modeled Stars and Massive Black Holes. I: Feedback-Regulated Star Formation and Black Hole Growth

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji-hoon; Wise, John H.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Princeton U., Astrophys. Sci. Dept.; Alvarez, Marcelo A.; /Canadian Inst. Theor. Astrophys.; Abel, Tom; /KIPAC, Menlo Park /Stanford U., Phys. Dept.

    2011-11-04

    There is mounting evidence for the coevolution of galaxies and their embedded massive black holes (MBHs) in a hierarchical structure formation paradigm. To tackle the nonlinear processes of galaxy-MBH interaction, we describe a self-consistent numerical framework which incorporates both galaxies and MBHs. The high-resolution adaptive mesh refinement (AMR) code Enzo is modified to model the formation and feedback of molecular clouds at their characteristic scale of 15.2 pc and the accretion of gas onto an MBH. Two major channels of MBH feedback, radiative feedback (X-ray photons followed through full three-dimensional adaptive ray tracing) and mechanical feedback (bipolar jets resolved in high-resolution AMR), are employed. We investigate the coevolution of a 9.2 x 10{sup 11} M {circle_dot} galactic halo and its 10{sup 5} {circle_dot} M embedded MBH at redshift 3 in a cosmological CDM simulation. The MBH feedback heats the surrounding interstellar medium (ISM) up to 10{sup 6} K through photoionization and Compton heating and locally suppresses star formation in the galactic inner core. The feedback considerably changes the stellar distribution there. This new channel of feedback from a slowly growing MBH is particularly interesting because it is only locally dominant and does not require the heating of gas globally on the disk. The MBH also self-regulates its growth by keeping the surrounding ISM hot for an extended period of time.

  10. A novel genetic mechanism regulates dorsolateral hinge-point formation during zebrafish cranial neurulation

    OpenAIRE

    Nyholm, Molly K.; Abdelilah-Seyfried, Salim; Grinblat, Yevgenya

    2009-01-01

    During neurulation, vertebrate embryos form a neural tube (NT), the rudiment of the central nervous system. In mammals and birds, a key step in cranial NT morphogenesis is dorsolateral hinge-point (DLHP) bending, which requires an apical actomyosin network. The mechanism of DLHP formation is poorly understood, although several essential genes have been identified, among them Zic2, which encodes a zinc-finger transcription factor. We found that DLHP formation in the zeb...

  11. Effects of H2 and Formate on Growth Yield and Regulation of Methanogenesis in Methanococcus maripaludis

    OpenAIRE

    Costa, Kyle C.; Yoon, Sung Ho; Pan, Min; Burn, June A.; Baliga, Nitin S.; Leigh, John A.

    2013-01-01

    Hydrogenotrophic methanogenic Archaea are defined by an H2 requirement for growth. Despite this requirement, many hydrogenotrophs are also capable of growth with formate as an electron donor for methanogenesis. While certain responses of these organisms to hydrogen availability have been characterized, responses to formate starvation have not been reported. Here we report that during continuous culture of Methanococcus maripaludis under defined nutrient conditions, growth yields relative to m...

  12. THE FORMATION OF ENTS ADAPTIVE REACTIONS DEPENDING ON THE TYPE OF PSYCHO-VEGETATIVE REGULATION

    OpenAIRE

    E. M. Kazin

    2014-01-01

    The purpose of the students (12 to 15 years old) examination was to identify the integrative criteria of assessing the nature of the functional relationships between the parameters of the psychosocial and physiological adaptation of students, depending on age, individual-typological peculiarities of vegetative regulation, personal potential at different stages of school education.The study of the characteristics of vegetative regulation of the cardiovascular system was made with a help of an ...

  13. Smooth muscle–endothelial cell communication activates Reelin signaling and regulates lymphatic vessel formation

    OpenAIRE

    Lutter, Sophie; Xie, Sherry; Tatin, Florence; Makinen, Taija

    2012-01-01

    Active lymph transport relies on smooth muscle cell (SMC) contractions around collecting lymphatic vessels, yet regulation of lymphatic vessel wall assembly and lymphatic pumping are poorly understood. Here, we identify Reelin, an extracellular matrix glycoprotein previously implicated in central nervous system development, as an important regulator of lymphatic vascular development. Reelin-deficient mice showed abnormal collecting lymphatic vessels, characterized by a reduced number of SMCs,...

  14. IL-33 inhibits RANKL-induced osteoclast formation through the regulation of Blimp-1 and IRF-8 expression

    International Nuclear Information System (INIS)

    Interleukin (IL)-33 is a recently discovered proinflammatory cytokine that belongs to the IL-1 family. Several studies have reported that IL-33 inhibits osteoclast differentiation. However, the mechanism of IL-33 regulation of osteoclastogenesis remains unclear. In the present study, we examined the effect of IL-33 on osteoclast formation in vitro. IL-33 suppressed osteoclast formation in both mouse bone marrow cells and monocyte/macrophage cell line RAW264.7 cells induced by receptor activator of NF-κB ligand (RANKL) and/or macrophage stimulating factor (M-CSF). IL-33 also inhibited the expression of RANKL-induced nuclear factor of activated T-cell cytoplasmic 1 (NFATc1), thereby decreasing the expression of osteoclastogenesis-related marker genes, including Cathepsin K, Osteoclast stimulatory transmembrane protein (Oc-stamp) and Tartrate-resistant acid phosphatase (Trap). Blockage of IL-33-ST2 binding suppressed the IL-33-mediated inhibition of NFATc1. RANKL-induced B-lymphocyte-induced maturation protein-1 (Blimp-1) expression was also suppressed by IL-33, which was followed by the stimulation of anti-osteoclastic genes such as interferon regulatory factor-8 (IRF-8). These results suggest that IL-33-ST2 interactions down-regulate both RANKL-induced NFATc1 activation and osteoclast differentiation via the regulation of Blimp-1 and IRF-8 expression. - Highlights: • IL-33 inhibits RANKL-induced osteoclast formation. • IL-33 has inhibitory effect on the RANKL-induced NFATc1 expression. • IL-33-induced NFATc1 suppression depends on the regulation of Blimp-1 and IRF-8

  15. IL-33 inhibits RANKL-induced osteoclast formation through the regulation of Blimp-1 and IRF-8 expression

    Energy Technology Data Exchange (ETDEWEB)

    Kiyomiya, Hiroyasu [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580 (Japan); Division of Oral and Maxillofacial Surgery, Department of Science of Physical Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580 (Japan); Ariyoshi, Wataru; Okinaga, Toshinori [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580 (Japan); Kaneuji, Takeshi [Division of Oral Medicine, Department of Science of Physical Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580 (Japan); Mitsugi, Sho [Division of Oral and Maxillofacial Surgery, Department of Science of Physical Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580 (Japan); Sakurai, Takuma [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580 (Japan); Division of Oral and Maxillofacial Surgery, Department of Science of Physical Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580 (Japan); Habu, Manabu [Division of Oral and Maxillofacial Surgery, Department of Science of Physical Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580 (Japan); Yoshioka, Izumi [Division of Oral Medicine, Department of Science of Physical Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580 (Japan); Tominaga, Kazuhiro [Division of Oral and Maxillofacial Surgery, Department of Science of Physical Functions, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580 (Japan); and others

    2015-05-01

    Interleukin (IL)-33 is a recently discovered proinflammatory cytokine that belongs to the IL-1 family. Several studies have reported that IL-33 inhibits osteoclast differentiation. However, the mechanism of IL-33 regulation of osteoclastogenesis remains unclear. In the present study, we examined the effect of IL-33 on osteoclast formation in vitro. IL-33 suppressed osteoclast formation in both mouse bone marrow cells and monocyte/macrophage cell line RAW264.7 cells induced by receptor activator of NF-κB ligand (RANKL) and/or macrophage stimulating factor (M-CSF). IL-33 also inhibited the expression of RANKL-induced nuclear factor of activated T-cell cytoplasmic 1 (NFATc1), thereby decreasing the expression of osteoclastogenesis-related marker genes, including Cathepsin K, Osteoclast stimulatory transmembrane protein (Oc-stamp) and Tartrate-resistant acid phosphatase (Trap). Blockage of IL-33-ST2 binding suppressed the IL-33-mediated inhibition of NFATc1. RANKL-induced B-lymphocyte-induced maturation protein-1 (Blimp-1) expression was also suppressed by IL-33, which was followed by the stimulation of anti-osteoclastic genes such as interferon regulatory factor-8 (IRF-8). These results suggest that IL-33-ST2 interactions down-regulate both RANKL-induced NFATc1 activation and osteoclast differentiation via the regulation of Blimp-1 and IRF-8 expression. - Highlights: • IL-33 inhibits RANKL-induced osteoclast formation. • IL-33 has inhibitory effect on the RANKL-induced NFATc1 expression. • IL-33-induced NFATc1 suppression depends on the regulation of Blimp-1 and IRF-8.

  16. Flower-bud formation in explants of photoperiodic and day-neutral Nicotiana biotypes and its bearing on the regulation of flower formation.

    Science.gov (United States)

    Rajeevan, M S; Lang, A

    1993-05-15

    The capacity to form flower buds in thin-layer explants was studied in flowering plants of several species, cultivars, and lines of Nicotiana differing in their response to photoperiod. This capacity was found in all biotypes examined and could extend into sepals and corolla. It varied greatly, depending on genotype, source tissue and its developmental stage, and composition of the culture medium, particularly the levels of glucose, auxin, and cytokinin. It was greatest in the two day-neutral plants examined, Samsun tobacco and Nicotiana rustica, where it extended from the inflorescence region down the vegetative stem, in a basipetally decreasing gradient; it was least in the two qualitative photoperiodic plants studied, the long-day plant Nicotiana silvestris and the short-day plant Maryland Mammoth tobacco, the quantitative long-day plant Nicotiana alata and the quantitative short-day plant Nicotiana otophora line 38-G-81, where it was limited to the pedicels (and, in some cases, the sepals). Regardless of the photoperiodic response of the source plants, the response was the same in explants cultured under long and short days. The finding that capacity to form flower buds in explants is present in all Nicotiana biotypes studied supports the idea that it is regulated by the same mechanism(s), regardless of the plant's photoperiodic character. However, the source plants were all in the flowering stage, and no flower-bud formation can be obtained in explants from strictly vegetative Nicotiana plants. Hence, flower formation in the explants is not identical with de novo flower formation in a hitherto vegetative plant: it is rather the expression of a floral state already established in the plant, although it can vary widely in extent and spatial distribution. Culture conditions that permit flower-bud formation in an explant are conditions that maintain the floral state and encourage its expression; conditions under which no flower buds are formed reduce this state

  17. Endothelial-Specific EphA4 Negatively Regulates Native Pial Collateral Formation and Re-Perfusion following Hindlimb Ischemia

    Science.gov (United States)

    Okyere, Benjamin; Giridhar, Kaavya; Hazy, Amanda; Chen, Miao; Keimig, David; Bielitz, Robert C.; Xie, Hehuang; He, Jia-Qiang; Huckle, William R.; Theus, Michelle H.

    2016-01-01

    Leptomeningeal anastomoses play a critical role in regulating vascular re-perfusion following obstruction, however, the mechanisms regulating their development remains under investingation. Our current findings indicate that EphA4 receptor is a novel negative regulator of collaterogenesis. We demonstrate that EphA4 is highly expressed on pial arteriole collaterals at post-natal day (P) 1 and 7, then significantly reduced by P21. Endothelial cell (EC)-specific loss of EphA4, EphA4f/f/Tie2::Cre (KO), resulted in an increase in the density but not diameter of pial collaterals compared to WT mice. ECs isolated from KO mice displayed a 3-fold increase in proliferation, enhanced migration, tube formation and elevated levels of phospho(p)-Akt compared to WT ECs. Attenuating p-Akt, using LY294002, reduced the proliferative and migration effects in the KO ECs. RNAseq analysis also revealed altered expression patterns for genes that regulate cell proliferation, vascular development, extracellular matrix and immune-mediate responses, namely MCP-1, MMP2 and angiopoietin-1. Lastly, we show that induction of hindlimb ischemia resulted in accelerated re-perfusion, collateral remodeling and reduced tissue necrosis in the absence of EC-specific EphA4 compared to WT mice. These findings demonstrate a novel role for EphA4 in the early development of the pial collateral network and suggests a role in regulating vascular remodeling after obstruction. PMID:27467069

  18. A putative ABC transporter is involved in negative regulation of biofilm formation by Listeria monocytogenes

    DEFF Research Database (Denmark)

    Zhu, Xinna; Long, Fei; Chen, Yonghui;

    2008-01-01

    Listeria monocytogenes may persist for long periods in food processing environments. In some instances, this may be due to aggregation or biofilm formation. To investigate the mechanism controlling biofilm formation in the food-borne pathogen L. monocytogenes, we characterized LM-49, a mutant with...... enhanced ability of biofilm-formation generated via transposon Tn917 mutagenesis of L. monocytogenes 4b G. In this mutant, a Tn917 insertion has disrupted the coding region of the gene encoding a putative ATP binding cassette (ABC) transporter permease identical to Lmof2365_1771 (a putative ABC......-transporter permease) presented in the sequenced strain L. monocytogenes str. 4b F2365. This disrupted gene, denoted lm.G_1771, encoded a protein with 10 transmembrane helixes. The revertant, LM-49RE, was obtained by replacing lm.G_1771::Tn917 with lm.G_1771 via homologous recombination. We found that LM-49RE formed...

  19. The transcriptional regulator c2h2 accelerates mushroom formation in Agaricus bisporus.

    Science.gov (United States)

    Pelkmans, Jordi F; Vos, Aurin M; Scholtmeijer, Karin; Hendrix, Ed; Baars, Johan J P; Gehrmann, Thies; Reinders, Marcel J T; Lugones, Luis G; Wösten, Han A B

    2016-08-01

    The Cys2His2 zinc finger protein gene c2h2 of Schizophyllum commune is involved in mushroom formation. Its inactivation results in a strain that is arrested at the stage of aggregate formation. In this study, the c2h2 orthologue of Agaricus bisporus was over-expressed in this white button mushroom forming basidiomycete using Agrobacterium-mediated transformation. Morphology, cap expansion rate, and total number and biomass of mushrooms were not affected by over-expression of c2h2. However, yield per day of the c2h2 over-expression strains peaked 1 day earlier. These data and expression analysis indicate that C2H2 impacts timing of mushroom formation at an early stage of development, making its encoding gene a target for breeding of commercial mushroom strains. PMID:27207144

  20. Pharmacologic regulation of AMPK in breast cancer affects cytoskeletal properties involved with microtentacle formation and re-attachment.

    Science.gov (United States)

    Chakrabarti, Kristi R; Whipple, Rebecca A; Boggs, Amanda E; Hessler, Lindsay K; Bhandary, Lekhana; Vitolo, Michele I; Thompson, Keyata; Martin, Stuart S

    2015-11-01

    The presence of tumor cells in the circulation is associated with a higher risk of metastasis in patients with breast cancer. Circulating breast tumor cells use tubulin-based structures known as microtentacles (McTNs) to re-attach to endothelial cells and arrest in distant organs. McTN formation is dependent on the opposing cytoskeletal forces of stable microtubules and the actin network. AMP-activated protein kinase (AMPK) is a cellular metabolic regulator that can alter actin and microtubule organization in epithelial cells. We report that AMPK can regulate the cytoskeleton of breast cancer cells in both attached and suspended conditions. We tested the effects of AMPK on microtubule stability and the actin-severing protein, cofilin. AMPK inhibition with compound c increased both microtubule stability and cofilin activation, which also resulted in higher McTN formation and re-attachment. Conversely, AMPK activation with A-769662 decreased microtubule stability and cofilin activation with concurrent decreases in McTN formation and cell re-attachment. This data shows for the first time that AMPK shifts the balance of cytoskeletal forces in suspended breast cancer cells, which affect their ability to form McTNs and re-attach. These results support a model where AMPK activators may be used therapeutically to reduce the metastatic efficiency of breast tumor cells. PMID:26431377

  1. The expression pattern and inhibitory influence of Tenascin-C on the growth of spiral ganglion neurons suggest a regulatory role as boundary formation molecule in the postnatal mouse inner ear.

    Science.gov (United States)

    Kwiatkowska, M; Reinhard, J; Roll, L; Kraft, N; Dazert, S; Faissner, A; Volkenstein, S

    2016-04-01

    Sensorineural hearing loss, as a consequence of acoustic trauma, aging, genetic defects or ototoxic drugs, is highly associated with irreversible damage of cochlear hair cells (HCs) and secondary degeneration of spiral ganglion (SG) cells. Cochlear implants (CIs), which bypass the lost HC function by direct electrical stimulation of the remaining auditory neurons, offer an effective therapy option. Several studies imply that components of the extracellular matrix (ECM) have a great impact on the adhesion and growth of spiral ganglion neurons (SGNs) during development. Based on these findings, ECM proteins might act as bioactive CI substrates to optimize the electrode-nerve interface and to improve efficacy of these implants. In the present study, we focused on the ECM glycoproteins Tenascin-C (TN-C), Laminin (LN), and Fibronectin (FN), which show a prominent expression along the growth route of SGNs and the niche around HCs during murine postnatal development in vivo. We compared their influence on adhesion, neurite length, and neurite number of SGNs in vitro. Moreover, we studied the expression of the chondroitin sulfate proteoglycan (CSPG) dermatan sulfate-dependent proteoglycan-1 (DSD-1-PG), an interaction partner of TN-C. In sum, our in vitro data suggest that TN-C acts as an anti-adhesive and inhibitory factor for the growth of SGNs. The DSD-1 carbohydrate epitope is specifically localized to HC stereocilia and SG fibers. Interestingly, TN-C and the DSD-1-PG exhibit a mutually exclusive expression pattern, with the exception of a very restricted region beneath the habenula perforata, where SG neurites grow through the basilar membrane (BM) toward the HCs. The complementary expression of TN-C, LN, FN, and the DSD-1 epitope suggests that TN-C may act as an important boundary formation molecule in the developing postnatal mouse inner ear, which makes it a promising candidate to regulate neurite outgrowth in the light of CIs. PMID:26812032

  2. Involvement of cyclin K posttranscriptional regulation in the formation of Artemia diapause cysts.

    Directory of Open Access Journals (Sweden)

    Yang Zhao

    Full Text Available BACKGROUND: Artemia eggs tend to develop ovoviviparously to yield nauplius larvae in good rearing conditions; while under adverse situations, they tend to develop oviparously and encysted diapause embryos are formed instead. However, the intrinsic mechanisms regulating this process are not well understood. PRINCIPAL FINDING: This study has characterized the function of cyclin K, a regulatory subunit of the positive transcription elongation factor b (P-TEFb in the two different developmental pathways of Artemia. In the diapause-destined embryo, Western blots showed that the cyclin K protein was down-regulated as the embryo entered dormancy and reverted to relatively high levels of expression once development resumed, consistent with the fluctuations in phosphorylation of position 2 serines (Ser2 in the C-terminal domain (CTD of the largest subunit (Rpb1 of RNA polymerase II (RNAP II. Interestingly, the cyclin K transcript levels remained constant during this process. In vitro translation data indicated that the template activity of cyclin K mRNA stored in the postdiapause cyst was repressed. In addition, in vivo knockdown of cyclin K in developing embryos by RNA interference eliminated phosphorylation of the CTD Ser2 of RNAP II and induced apoptosis by inhibiting the extracellular signal-regulated kinase (ERK survival signaling pathway. CONCLUSIONS/SIGNIFICANCE: Taken together, these findings reveal a role for cyclin K in regulating RNAP II activity during diapause embryo development, which involves the post-transcriptional regulation of cyclin K. In addition, a further role was identified for cyclin K in regulating the control of cell survival during embryogenesis through ERK signaling pathways.

  3. Life and death in the placenta: new peptides and genes regulating human syncytiotrophoblast and extravillous cytotrophoblast lineage formation and renewal.

    Science.gov (United States)

    Morrish, D W; Dakour, J; Li, H

    2001-09-01

    Differential techniques have revealed several novel genes and peptides involved in trophoblast development including PL74/gdf15/MIC-1, a TGFbeta family cytokine that controls apoptosis and differentiation, PL48, a new serine-threonine protein kinase, serum and glucocorticoid-induced kinase, PBK-1, a tunicamycin-responsive gene, a cathepsin D-like gene (DAP-1) and hypoxia- regulated genes HRF-1,2,6,8 and HIF-1alpha, HIF-1beta, and hEPAS-1. Syncytin, a cell fusion- inducing gene, has been cloned from placenta where it regulates cell fusion. ERV-3 has also been demonstrated to promote cell fusion. These two genes represent the first demonstrated functions of endogenous retroviral sequences in human tissues. Endoglin, PlGF, TGFbeta3, IGF-II, IGFBP-1, and a placental IGFBP protease have found new roles in regulating cytotrophoblast proliferation and invasiveness. A specific placental p105 rasGAP protein has been identified. The homeobox genes DLX4, HB24, MSX2 and MOX2 also likely play a role in development at the epithelial-mesenchymal boundary. Transcription factors such as TEF-5, Hand1, HEB, HASH-2 and two genes represented by ESTs may have regulatory roles in placental development. Evidence suggests that the placenta has an unusual two-cell system for apoptosis regulation in which the cytotrophoblast may direct later apoptotic events in the syncytium, and with syncytialization possibly triggered by the "phosphatidylserine flip". Thus, the placenta is both a rich source of new growth-regulatory substances, and a model system for originating new paradigms of developmental biology. PMID:12369935

  4. AMP-activated protein kinase (AMPK) activation regulates in vitro bone formation and bone mass

    OpenAIRE

    Shah, M; Kola, B; Bataveljic, A.; Arnett, T. R.; Viollet, B.; Saxon, L.; Korbonits, M.; C. Chenu

    2010-01-01

    Adenosine 5′-monophosphate-activated protein kinase (AMPK), a regulator of energy homeostasis, has a central role in mediating the appetite-modulating and metabolic effects of many hormones and antidiabetic drugs metformin and glitazones. The objective of this study was to determine if AMPK can be activated in osteoblasts by known AMPK modulators and if AMPK activity is involved in osteoblast function in vitro and regulation of bone mass in vivo. ROS 17/2.8 rat osteoblast-like cells were cult...

  5. State regulation and teaching staff formation during the last military dictatorship in Buenos Aires Province

    Directory of Open Access Journals (Sweden)

    Myriam Southwell

    2009-06-01

    Full Text Available The last Argentine military dictatorship (1976-1983 has left deep marks in different spheres of the social, and education has not been the exception. A group of educational policies were carried out in the province of Buenos Aires that strongly transformed the senses of teaching. One of those policies has been the teacher education reform and the new course of studies for the Higher Teaching in 1977. From the advances of an ongoing research and the work on historical sources –programs, plans, regulations, government decrees, acts- we will analyse this teacher education policy as part of the teachers' work regulation and as a process of practice production.

  6. Regulation of Amidase Formation in Mutants from Pseudomonas aeruginosa PAO Lacking Glutamine Synthetase Activity

    NARCIS (Netherlands)

    Janssen, Dick B.; Herst, Patricia M.; Joosten, Han M.L.J.; Drift, Chris van der

    1982-01-01

    The formation of amidase was studied in mutants from Pseudomonas aeruginosa PAO lacking glutamine synthetase activity. It appeared that catabolite repression of amidase synthesis by succinate was partially relieved when cellular growth was limited by glutamine. Under these conditions, a correlation

  7. Twin boundary interactions with grain boundaries investigated in pure rhenium

    International Nuclear Information System (INIS)

    The mechanical behavior of pure rhenium was investigated using uniaxial compression tests, transmission electron microscopy and electron backscatter diffraction characterization. The plasticity was characterized by a large amount of twin formation and propagation, including twin transmission across grain boundaries. In-depth analysis of the interactions of {112¯1}〈1¯1¯26〉 twins with grain boundaries found that grain boundaries with misorientation angles below ∼25° allowed twin transmission, while grain boundaries with higher angles did not. Similar to dislocation interactions with grain boundaries, twin transmission was largely dictated by the minimization of the angle between the shear vectors of the incoming and outgoing twins

  8. Transcriptomic analysis reveals ethylene as stimulator and auxin as regulator of adventitious root formation in petunia cuttings

    Directory of Open Access Journals (Sweden)

    Uwe eDruege

    2014-09-01

    Full Text Available Adventitious root (AR formation in the stem base of cuttings is the basis for propagation of many plant species and petunia is used as model to study this developmental process. Following AR formation from 2 to 192 hours after excision (hpe of cuttings, transcriptome analysis by microarray revealed a change of the character of the rooting zone from stem base to root identity. The greatest shift in the number of differentially expressed genes was observed between 24 and 72 hpe, when the categories storage, mineral nutrient acquisition, anti-oxidative and secondary metabolism, and biotic stimuli showed a notable high number of induced genes. Analyses of phytohormone-related genes disclosed multifaceted changes of the auxin transport system, auxin conjugation and the auxin signal perception machinery indicating a reduction in auxin sensitivity and phase-specific responses of particular auxin-regulated genes. Genes involved in ethylene biosynthesis and action showed a more uniform pattern as a high number of respective genes were generally induced during the whole process of AR formation. The important role of ethylene for stimulating AR formation was demonstrated by the application of inhibitors of ethylene biosynthesis and perception as well as of the precursor aminocyclopropane-1-carboxylic acid, all changing the number and length of AR. A model is proposed showing the putative role of polar auxin transport and resulting auxin accumulation in initiation of subsequent changes in auxin homeostasis and signal perception with a particular role of Aux/IAA expression. These changes might in turn guide the entrance into the different phases of AR formation. Ethylene biosynthesis, which is stimulated by wounding and does probably also respond to other stresses and auxin, acts as important stimulator of AR formation probably via the expression of ethylene responsive transcription factor genes, whereas the timing of different phases seems to be controlled

  9. MADS-Box Transcription Factor VdMcm1 Regulates Conidiation, Microsclerotia Formation, Pathogenicity, and Secondary Metabolism of Verticillium dahliae.

    Science.gov (United States)

    Xiong, Dianguang; Wang, Yonglin; Tian, Longyan; Tian, Chengming

    2016-01-01

    Verticillium dahliae, a notorious phytopathogenic fungus, causes vascular wilt diseases in many plant species resulting in devastating yield losses worldwide. Due to its ability to colonize plant xylem and form microsclerotia, V. dahliae is highly persistent and difficult to control. In this study, we show that the MADS-box transcription factor VdMcm1 is a key regulator of conidiation, microsclerotia formation, virulence, and secondary metabolism of V. dahliae. In addition, our findings suggest that VdMcm1 is involved in cell wall integrity. Finally, comparative RNA-Seq analysis reveals 823 significantly downregulated genes in the VdMcm1 deletion mutant, with diverse biological functions in transcriptional regulation, plant infection, cell adhesion, secondary metabolism, transmembrane transport activity, and cell secretion. When taken together, these data suggest that VdMcm1 performs pleiotropic functions in V. dahliae. PMID:27536281

  10. The WUSCHEL-RELATED HOMEOBOX 3 gene PaWOX3 regulates lateral organ formation in Norway spruce

    OpenAIRE

    Alvarez, Jose M.; Sohlberg, Joel; Engström, Peter; Zhu, Tianqing; Englund, Marie; Moschou, Panagiotis N.; Von Arnold, Sara

    2015-01-01

    In angiosperms, WUSCHEL-RELATED HOMEOBOX 3 (WOX3) genes are required for the recruitment of founder cells from the lateral domains of shoot meristems that form lateral regions of leaves. However, the regulation of the formation of lateral organs in gymnosperms remains unknown. By using somatic embryos of Norway spruce ( Picea abies) we have studied the expression and function of PaWOX3 during embryo development. The mRNA abundance of PaWOX3 was determined by quantitative real-time PCR, and th...

  11. GABAergic Transmission in Rat Pontine Reticular Formation Regulates the Induction Phase of Anesthesia and Modulates Hyperalgesia Caused by Sleep Deprivation

    OpenAIRE

    Vanini, Giancarlo; Nemanis, Kriste; Baghdoyan, Helen A.; Lydic, Ralph

    2014-01-01

    The oral part of the pontine reticular formation (PnO) contributes to the regulation of sleep, anesthesia, and pain. The role of PnO GABA in modulating these states remains incompletely understood. The present study used time to Loss and time to Resumption of Righting Response (LoRR and RoRR) as surrogate measures of loss and resumption of consciousness. This study tested three hypotheses: (1) pharmacologically manipulating GABA levels in rat PnO alters LoRR, RoRR, and nociception; (2) propof...

  12. Gravity-regulated formation of the peg in developing cucumber seedlings

    Science.gov (United States)

    Takahashi, H.; Scott, T. K.

    1994-01-01

    It has been proposed that peg formation in the vascular transition region (TR zone) between the hypocotyl and the root in Cucurbitaceae seedlings is a gravimorphogenetic phenomenon. Initiation of the peg became visible 36 h after imbibition when cucumber (Cucumis sativus L. cv. Burpee Hybrid II) seeds were germinated in a horizontal position at 24 degrees C in the dark. Simultaneously, sedimented amyloplasts (putative statoliths) were apparent in the sheath cells surrounding the vascular strands, and in the cortical cells immediately adjacent to them, in the TR zone. In contrast, the other cortical cells, some of which were destined to develop into the peg, contained amyloplasts which were not sedimented. These results suggest that the graviperception mechanism for peg formation may be like that of statoliths in shoot gravitropism. By 48 h following imbibition, the cells of the TR zone still had sedimented amyloplasts but had lost their sensitivity to gravity, possibly because of their maturation.

  13. HD-GYP domain proteins regulate biofilm formation and virulence in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Ryan, Robert P.; Lucey, Jean; O'Donovan, Karen;

    2009-01-01

    residues (YN-GYP). Here we have investigated the role of these proteins in biofilm formation, virulence factor synthesis and virulence of P. aeruginosa. Mutation of PA4108 and PA4781 led to an increase in the level of cyclic-di-GMP in P. aeruginosa, consistent with the predicted activity of the encoded...... proteins as cyclic-di-GMP phosphodiesterases. Mutation of both genes led to reduced swarming motility but had differing effects on production of the virulence factors pyocyanin, pyoverdin and ExoS. Mutation of PA2572 had no effect on cyclic-di-GMP levels and did not influence swarming motility. However, PA......2572 had a negative influence on swarming that was cryptic and was revealed only after removal of an uncharacterized C-terminal domain. Mutation of PA4108, PA4781 and PA2572 had distinct effects on biofilm formation and architecture of P. aeruginosa. All three proteins contributed to virulence of P...

  14. Phosphate Interacts With PTHrP to Regulate Endochondral Bone Formation

    OpenAIRE

    Liu, Eva S.; Zalutskaya, Alena; Chae, Byongsoo Timothy; Zhu, Eric D.; Gori, Francesca; Demay, Marie B.

    2014-01-01

    Phosphate and parathyroid hormone related peptide (PTHrP) are required for normal growth plate maturation. Hypophosphatemia impairs hypertrophic chondrocyte apoptosis leading to rachitic expansion of the growth plate; however, the effect of phosphate restriction on chondrocyte differentiation during endochondral bone formation has not been examined. Investigations were, therefore, undertaken to address whether phosphate restriction alters the maturation of embryonic d15.5 murine metatarsal el...

  15. Illegal formation (creation, reorganization) of a juridical person: issues of qualification and legal regulation of liability

    OpenAIRE

    Natalya Aleksandrovna Egorova; Aleksandr Aleksandrovich Likholetov

    2015-01-01

    Objective to analyze the disposition of part 1 of Article 173.1 of the Russian Criminal Code and comments to this Article to identify their shortcomings to consider problems of practical application of Article 173.1 and to formulate proposals on legislation improvement aimed at increasing the efficiency of counteraction to illegal formation of a juridical person. Methods a combination of general scientific induction deduction analysis and synthesis and specific scientific formallegal...

  16. Klf5 regulates lineage formation in the pre-implantation mouse embryo

    OpenAIRE

    Lin, Suh-Chin J.; Wani, Maqsood A.; Whitsett, Jeffrey A.; Wells, James M.

    2010-01-01

    Kruppel-like transcription factors (Klfs) are essential for the induction and maintenance of pluripotency of embryonic stem cells (ESCs), yet little is known about their roles in establishing the three lineages of the pre-implantation embryo. Here, we show that Klf5 is required for the formation of the trophectoderm (TE) and the inner cell mass (ICM), and for repressing primitive endoderm (PE) development. Although cell polarity appeared normal, Klf5 mutant embryos arrested at the blastocyst ...

  17. RIP140 contributes to foam cell formation and atherosclerosis by regulating cholesterol homeostasis in macrophages

    OpenAIRE

    Lin, Yi-Wei; Liu, Pu-Ste; Adhikari, Neeta; Jennifer L Hall; Wei, Li-Na

    2014-01-01

    Atherosclerosis, a syndrome with abnormal arterial walls, is one of the major causes that lead to the development of various cardiovascular diseases. The key initiator of atherosclerosis is cholesterol accumulation. The uncontrolled cholesterol deposition, mainly involving low-density lipoprotein (LDL), causes atheroma plaque formation, which initiates chronic inflammation due to the recruitment of inflammatory cells such as macrophages. Macrophages scavenge excess peripheral cholesterol and ...

  18. BpsR Modulates Bordetella Biofilm Formation by Negatively Regulating the Expression of the Bps Polysaccharide

    OpenAIRE

    Conover, Matt S.; Redfern, Crystal J.; Ganguly, Tridib; Sukumar, Neelima; Sloan, Gina; Mishra, Meenu; Deora, Rajendar

    2012-01-01

    Bordetella bacteria are Gram-negative respiratory pathogens of animals, birds, and humans. A hallmark feature of some Bordetella species is their ability to efficiently survive in the respiratory tract even after vaccination. Bordetella bronchiseptica and Bordetella pertussis form biofilms on abiotic surfaces and in the mouse respiratory tract. The Bps exopolysaccharide is one of the critical determinants for biofilm formation and the survival of Bordetella in the murine respiratory tract. In...

  19. Dust-regulated galaxy formation and evolution:A new chemodynamical model with live dust particles

    CERN Document Server

    Bekki, Kenji

    2015-01-01

    Interstellar dust plays decisive roles in the conversion of neutral to molecular hydrogen (H_2), the thermodynamical evolution of interstellar medium (ISM), and the modification of spectral energy distributions (SEDs) of galaxies. These important roles of dust have not been self-consistently included in previous numerical simulations of galaxy formation and evolution. We have therefore developed a new model by which one can investigate whether and how galaxy formation and evolution can be influenced by dust-related physical processes such as photo-electric heating, H_2 formation on dust, and stellar radiation pressure on dust in detail. A novel point of the model is that different dust species in a galaxy are represented by `live dust' particles (i.e., not test particles). Therefore, dust particles in a galaxy not only interact gravitationally with all four components of the galaxy (i.e., dark matter, stars, gas, and dust) but also are grown and destroyed through physical processes of ISM. First we describe a...

  20. Operon Formation is Driven by Co-Regulation and Not by Horizontal Gene Transfer

    Energy Technology Data Exchange (ETDEWEB)

    Price, Morgan N.; Huang, Katherine H.; Arkin, Adam P.; Alm, Eric J.

    2005-04-12

    Although operons are often subject to horizontal gene transfer (HGT), non-HGT genes are particularly likely to be in operons. To resolve this apparent discrepancy and to determine whether HGT is involved in operon formation, we examined the evolutionary history of the genes and operons in Escherichia coli K12. We show that genes that have homologs in distantly related bacteria but not in close relatives of E. coli (indicating HGTi) form new operons at about the same rates as native genes. Furthermore, genes in new operons are no more likely than other genes to have phylogenetic trees that are inconsistent with the species tree. In contrast, essential genes and ubiquitous genes without paralogs (genes believed to undergo HGT rarely) often form new operons. We conclude that HGT is not associated with operon formation, but instead promotes the prevalence of pre-existing operons. To explain operon formation, we propose that new operons reduce the amount of regulatory information required to specify optimal expression patterns. Consistent with this hypothesis, operons have greater amounts of conserved regulatory sequences than do individually transcribed genes.

  1. The formation, function and regulation of amyloids: insights from structural biology.

    Science.gov (United States)

    Landreh, M; Sawaya, M R; Hipp, M S; Eisenberg, D S; Wüthrich, K; Hartl, F U

    2016-08-01

    Amyloid diseases are characterized by the accumulation of insoluble, β-strand-rich aggregates. The underlying structural conversions are closely associated with cellular toxicity, but can also drive the formation of functional protein assemblies. In recent years, studies in the field of structural studies have revealed astonishing insights into the origins, mechanisms and implications of amyloid formation. Notably, high-resolution crystal structures of peptides in amyloid-like fibrils and prefibrillar oligomers have become available despite their challenging chemical nature. Nuclear magnetic resonance spectroscopy has revealed that dynamic local polymorphisms in the benign form of the prion protein affect the transformation into amyloid fibrils and the transmissibility of prion diseases. Studies of the structures and interactions of chaperone proteins help us to understand how the cellular proteostasis network is able to recognize different stages of aberrant protein folding and prevent aggregation. In this review, we will focus on recent developments that connect the different aspects of amyloid biology and discuss how understanding the process of amyloid formation and the associated defence mechanisms can reveal targets for pharmacological intervention that may become the first steps towards clinically viable treatment strategies. PMID:27237473

  2. Pakistan Labor Market Study: Regulation, Job Creation, and Skills Formation in the Manufacturing Sector

    OpenAIRE

    Akhlaque, Asya; Heltberg, Rasmus; Mengistae, Taye

    2006-01-01

    In an effort to improve employment outcomes and industrial productivity, the Government of Pakistan (GoP) has launched a dual-track reform process involving broad-based overhaul of labor laws and institutions, and expansion and reform of the Vocational and Technical Training (VTT) system. Labor market regulation and laws are useful economic and social institutions designed to protect workers from undesirable consequences of market failure such as arbitrary or discriminatory actions by employe...

  3. Ras-Mek-Erk Signaling Regulates Nf1 Heterozygous Neointima Formation

    OpenAIRE

    Stansfield, Brian K.; Bessler, Waylan K.; Mali, Raghuveer; Mund, Julie A.; Downing, Brandon D.; Kapur, Reuben; Ingram, David A.

    2014-01-01

    Neurofibromatosis type 1 (NF1) results from mutations in the NF1 tumor-suppressor gene, which encodes neurofibromin, a negative regulator of diverse Ras signaling cascades. Arterial stenosis is a nonneoplastic manifestation of NF1 that predisposes some patients to debilitating morbidity and sudden death. Recent murine studies demonstrate that Nf1 heterozygosity (Nf1+/−) in monocytes/macrophages significantly enhances intimal proliferation after arterial injury. However, the downstream Ras eff...

  4. Pyk2 Regulates Megakaryocyte-Induced Increases in Osteoblast Number and Bone Formation

    OpenAIRE

    Cheng, Ying-Hua; Hooker, R. Adam; NGUYEN, Khanh; Gerard-O’Riley, Rita; Waning, David L.; Chitteti, Brahmananda R; Meijome, Tomas E.; Chua, Hui Lin; Plett, Artur P.; Orschell, Christie M.; Srour, Edward F.; Mayo, Lindsey D.; Pavalko, Fredrick M; Bruzzaniti, Angela; Kacena, Melissa A.

    2013-01-01

    Pre-clinical and clinical evidence from megakaryocyte (MK) related diseases suggest that MKs play a significant role in maintaining bone homeostasis. Findings from our laboratories reveal that MKs significantly increase osteoblast (OB) number through direct MK-OB contact and the activation of integrins. We therefore examined the role of Pyk2, a tyrosine kinase known to be regulated downstream of integrins, in the MK-mediated enhancement of OBs. When OBs were co-cultured with MKs, total Pyk2 l...

  5. Transcriptomic Analysis of the Regulation of Rhizome Formation in Temperate and Tropical Lotus (Nelumbo nucifera)

    OpenAIRE

    Mei Yang; Lingping Zhu; Cheng Pan; Liming Xu; Yanling Liu; Weidong Ke; Pingfang Yang

    2015-01-01

    Rhizome is the storage organ of lotus derived from modified stems. The development of rhizome is a complex process and depends on the balanced expression of the genes that is controlled by environmental and endogenous factors. However, little is known about the mechanism that regulates rhizome girth enlargement. In this study, using RNA-seq, transcriptomic analyses were performed at three rhizome developmental stages—the stolon, middle swelling and later swelling stage —in the cultivars ‘ZO’ ...

  6. FOOD INTAKE REGULATES OLEOYLETHANOLAMIDE FORMATION AND DEGRADATION IN THE PROXIMAL SMALL INTESTINE

    OpenAIRE

    Fu, Jin; Astarita, Giuseppe; Gaetani, Silvana; Kim, Janet; Cravatt, Benjamin F.; Mackie, Ken; Piomelli, Daniele

    2006-01-01

    Oleoylethanolamide (OEA) is a lipid mediator that inhibits food intake by activating the nuclear receptor peroxisome proliferator-activated receptor- α (PPAR-α). In the rodent small intestine, OEA levels decrease during food deprivation and increase upon refeeding, suggesting that endogenous OEA may participate in the regulation of satiety. Here we show that feeding stimulates OEA mobilization in the mucosal layer of rat duodenum and jejunum, but not in the serosal layer from the same intesti...

  7. Tsukushi modulates Xnr2, FGF and BMP signaling: regulation of Xenopus germ layer formation.

    Directory of Open Access Journals (Sweden)

    Samantha A Morris

    Full Text Available BACKGROUND: Cell-cell communication is essential in tissue patterning. In early amphibian development, mesoderm is formed in the blastula-stage embryo through inductive interactions in which vegetal cells act on overlying equatorial cells. Members of the TGF-beta family such as activin B, Vg1, derrière and Xenopus nodal-related proteins (Xnrs are candidate mesoderm inducing factors, with further activity to induce endoderm of the vegetal region. TGF-beta-like ligands, including BMP, are also responsible for patterning of germ layers. In addition, FGF signaling is essential for mesoderm formation whereas FGF signal inhibition has been implicated in endoderm induction. Clearly, several signaling pathways are coordinated to produce an appropriate developmental output; although intracellular crosstalk is known to integrate multiple pathways, relatively little is known about extracellular coordination. METHODOLOGY/PRINCIPAL FINDINGS: Here, we show that Xenopus Tsukushi (X-TSK, a member of the secreted small leucine rich repeat proteoglycan (SLRP family, is expressed in ectoderm, endoderm, and the organizer during early development. We have previously reported that X-TSK binds to and inhibits BMP signaling in cooperation with chordin. We now demonstrate two novel interactions: X-TSK binds to and inhibits signaling by FGF8b, in addition to binding to and enhancement of Xnr2 signaling. This signal integration by X-TSK at the extracellular level has an important role in germ layer formation and patterning. Vegetally localized X-TSK potentiates endoderm formation through coordination of BMP, FGF and Xnr2 signaling. In contrast, X-TSK inhibition of FGF-MAPK signaling blocks ventrolateral mesoderm formation, while BMP inhibition enhances organizer formation. These actions of X-TSK are reliant upon its expression in endoderm and dorsal mesoderm, with relative exclusion from ventrolateral mesoderm, in a pattern shaped by FGF signals. CONCLUSIONS

  8. Zinc regulates iNOS-derived nitric oxide formation in endothelial cells

    Directory of Open Access Journals (Sweden)

    Miriam M. Cortese-Krott

    2014-01-01

    Full Text Available Aberrant production of nitric oxide (NO by inducible NO synthase (iNOS has been implicated in the pathogenesis of endothelial dysfunction and vascular disease. Mechanisms responsible for the fine-tuning of iNOS activity in inflammation are still not fully understood. Zinc is an important structural element of NOS enzymes and is known to inhibit its catalytical activity. In this study we aimed to investigate the effects of zinc on iNOS activity and expression in endothelial cells. We found that zinc down-regulated the expression of iNOS (mRNA+protein and decreased cytokine-mediated activation of the iNOS promoter. Zinc-mediated regulation of iNOS expression was due to inhibition of NF-κB transactivation activity, as determined by a decrease in both NF-κB-driven luciferase reporter activity and expression of NF-κB target genes, including cyclooxygenase 2 and IL-1β. However, zinc did not affect NF-κB translocation into the nucleus, as assessed by Western blot analysis of nuclear and cytoplasmic fractions. Taken together our results demonstrate that zinc limits iNOS-derived high output NO production in endothelial cells by inhibiting NF-κB-dependent iNOS expression, pointing to a role of zinc as a regulator of iNOS activity in inflammation.

  9. Evolution-development congruence in pattern formation dynamics: Bifurcations in gene expression and regulation of networks structures.

    Science.gov (United States)

    Kohsokabe, Takahiro; Kaneko, Kunihiko

    2016-01-01

    Search for possible relationships between phylogeny and ontogeny is important in evolutionary-developmental biology. Here we uncover such relationships by numerical evolution and unveil their origin in terms of dynamical systems theory. By representing developmental dynamics of spatially located cells with gene expression dynamics with cell-to-cell interaction under external morphogen gradient, gene regulation networks are evolved under mutation and selection with the fitness to approach a prescribed spatial pattern of expressed genes. For most numerical evolution experiments, evolution of pattern over generations and development of pattern by an evolved network exhibit remarkable congruence. Both in the evolution and development pattern changes consist of several epochs where stripes are formed in a short time, while for other temporal regimes, pattern hardly changes. In evolution, these quasi-stationary regimes are generations needed to hit relevant mutations, while in development, they are due to some gene expression that varies slowly and controls the pattern change. The morphogenesis is regulated by combinations of feedback or feedforward regulations, where the upstream feedforward network reads the external morphogen gradient, and generates a pattern used as a boundary condition for the later patterns. The ordering from up to downstream is common in evolution and development, while the successive epochal changes in development and evolution are represented as common bifurcations in dynamical-systems theory, which lead to the evolution-development congruence. Mechanism of exceptional violation of the congruence is also unveiled. Our results provide a new look on developmental stages, punctuated equilibrium, developmental bottlenecks, and evolutionary acquisition of novelty in morphogenesis. PMID:26678220

  10. Solution NMR structure of CsgE: Structural insights into a chaperone and regulator protein important for functional amyloid formation.

    Science.gov (United States)

    Shu, Qin; Krezel, Andrzej M; Cusumano, Zachary T; Pinkner, Jerome S; Klein, Roger; Hultgren, Scott J; Frieden, Carl

    2016-06-28

    Curli, consisting primarily of major structural subunit CsgA, are functional amyloids produced on the surface of Escherichia coli, as well as many other enteric bacteria, and are involved in cell colonization and biofilm formation. CsgE is a periplasmic accessory protein that plays a crucial role in curli biogenesis. CsgE binds to both CsgA and the nonameric pore protein CsgG. The CsgG-CsgE complex is the curli secretion channel and is essential for the formation of the curli fibril in vivo. To better understand the role of CsgE in curli formation, we have determined the solution NMR structure of a double mutant of CsgE (W48A/F79A) that appears to be similar to the wild-type (WT) protein in overall structure and function but does not form mixed oligomers at NMR concentrations similar to the WT. The well-converged structure of this mutant has a core scaffold composed of a layer of two α-helices and a layer of three-stranded antiparallel β-sheet with flexible N and C termini. The structure of CsgE fits well into the cryoelectron microscopy density map of the CsgG-CsgE complex. We highlight a striking feature of the electrostatic potential surface in CsgE structure and present an assembly model of the CsgG-CsgE complex. We suggest a structural mechanism of the interaction between CsgE and CsgA. Understanding curli formation can provide the information necessary to develop treatments and therapeutic agents for biofilm-related infections and may benefit the prevention and treatment of amyloid diseases. CsgE could establish a paradigm for the regulation of amyloidogenesis because of its unique role in curli formation. PMID:27298344

  11. Sialic Acid on the Glycosylphosphatidylinositol Anchor Regulates PrP-mediated Cell Signaling and Prion Formation.

    Science.gov (United States)

    Bate, Clive; Nolan, William; Williams, Alun

    2016-01-01

    The prion diseases occur following the conversion of the cellular prion protein (PrP(C)) into disease-related isoforms (PrP(Sc)). In this study, the role of the glycosylphosphatidylinositol (GPI) anchor attached to PrP(C) in prion formation was examined using a cell painting technique. PrP(Sc) formation in two prion-infected neuronal cell lines (ScGT1 and ScN2a cells) and in scrapie-infected primary cortical neurons was increased following the introduction of PrP(C). In contrast, PrP(C) containing a GPI anchor from which the sialic acid had been removed (desialylated PrP(C)) was not converted to PrP(Sc). Furthermore, the presence of desialylated PrP(C) inhibited the production of PrP(Sc) within prion-infected cortical neurons and ScGT1 and ScN2a cells. The membrane rafts surrounding desialylated PrP(C) contained greater amounts of sialylated gangliosides and cholesterol than membrane rafts surrounding PrP(C). Desialylated PrP(C) was less sensitive to cholesterol depletion than PrP(C) and was not released from cells by treatment with glimepiride. The presence of desialylated PrP(C) in neurons caused the dissociation of cytoplasmic phospholipase A2 from PrP-containing membrane rafts and reduced the activation of cytoplasmic phospholipase A2. These findings show that the sialic acid moiety of the GPI attached to PrP(C) modifies local membrane microenvironments that are important in PrP-mediated cell signaling and PrP(Sc) formation. These results suggest that pharmacological modification of GPI glycosylation might constitute a novel therapeutic approach to prion diseases. PMID:26553874

  12. Regulation of multiple tip formation by caffeine in cellular slime molds

    Directory of Open Access Journals (Sweden)

    Jaiswal Pundrik

    2012-08-01

    Full Text Available Abstract Background The multicellular slug in Dictyostelium has a single tip that acts as an organising centre patterning the rest of the slug. High adenosine levels at the tip are believed to be responsible for this tip dominance and the adenosine antagonist, caffeine overrides this dominance promoting multiple tip formation. Results Caffeine induced multiple tip effect is conserved in all the Dictyostelids tested. Two key components of cAMP relay namely, cAMP phosphodiesterase (Pde4 and adenyl cyclase-A (AcaA levels get reduced during secondary tip formation in Dictyostelium discoideum. Pharmacological inhibition of cAMP phosphodiesterase also resulted in multiple tips. Caffeine reduces cAMP levels by 16.4, 2.34, 4.71 and 6.30 folds, respectively in D. discoideum, D. aureostipes, D. minutum and Polysphondylium pallidum. We propose that altered cAMP levels, perturbed cAMP gradient and impaired signalling may be the critical factors for the origin of multiple tips in other Dictyostelids as well. In the presence of caffeine, slug cell movement gets impaired and restricted. The cell type specific markers, ecmA (prestalk and pspA (prespore cells are not equally contributing during additional tip formation. During additional tip emergence, prespore cells transdifferentiate to compensate the loss of prestalk cells. Conclusion Caffeine decreases adenyl cyclase–A (AcaA levels and as a consequence low cAMP is synthesised altering the gradient. Further if cAMP phosphodiesterase (Pde4 levels go down in the presence of caffeine, the cAMP gradient breaks down. When there is no cAMP gradient, directional movement is inhibited and might favour re-differentiation of prespore to prestalk cells.

  13. Illegal formation (creation, reorganization of a juridical person: issues of qualification and legal regulation of liability

    Directory of Open Access Journals (Sweden)

    Natalya Aleksandrovna Egorova

    2015-06-01

    Full Text Available Objective to analyze the disposition of part 1 of Article 173.1 of the Russian Criminal Code and comments to this Article to identify their shortcomings to consider problems of practical application of Article 173.1 and to formulate proposals on legislation improvement aimed at increasing the efficiency of counteraction to illegal formation of a juridical person. Methods a combination of general scientific induction deduction analysis and synthesis and specific scientific formallegal comparative legal sociological content analysis methods. Results the paper proposes an analysis of Article 173.1 of the Criminal Code and the current state of law enforcement practice on criminal cases concerning the illegal formation creation reorganization of a juridical person. Basing on empirical material the authors show the problems in classification of these crimes. The authors conclude that the unsatisfactory results of the struggle against quotshortlivedquot companies result mainly from the imperfection of the existing criminal law and prove the need for decriminalization of these crimes simultaneously establishing administrative liability for such acts and excepting Article 173.1 from the Criminal Code or changing its content. Scientific novelty basing on the existing legal norms modern scientific literature on the topic and materials on applying Article 173.1 of the Russian Criminal Code the article studies the signs of illegal formation creation reorganization of a juridical person which cause the greatest difficulties in the crime qualification and sets out the author39s proposals on legislation improvement in particular an exemplary article of the Administrative Code of the Russian Federation on formation creation reorganization of quotshortlivedrdquo companies. Practical value the judgments and conclusions contained in the article can be used in lawmaking activities for the development of draft laws on introducing changes and amendments to the

  14. Regulation of male sex determination: genital ridge formation and Sry activation in mice

    OpenAIRE

    Tanaka, Satomi S.; Nishinakamura, Ryuichi

    2014-01-01

    Sex determination is essential for the sexual reproduction to generate the next generation by the formation of functional male or female gametes. In mammals, primary sex determination is commenced by the presence or absence of the Y chromosome, which controls the fate of the gonadal primordium. The somatic precursor of gonads, the genital ridge is formed at the mid-gestation stage and gives rise to one of two organs, a testis or an ovary. The fate of the genital ridge, which is governed by th...

  15. Essential Roles and Regulation of the Legionella pneumophila Collagen-Like Adhesin during Biofilm Formation

    OpenAIRE

    Julia Mallegol; Carla Duncan; Akriti Prashar; Jannice So; Low, Donald E.; Mauricio Terebeznik; Cyril Guyard

    2012-01-01

    Legionellosis is mostly caused by Legionella pneumophila (Lp) and is defined by a severe respiratory illness with a case fatality rate ranging from 5 to 80%. In a previous study, we showed that a glycosaminoglycan (GAG)-binding adhesin of Lp, named Lcl, is produced during legionellosis and is unique to the L. pneumophila species. Importantly, a mutant depleted in Lcl (Δlpg2644) is impaired in adhesion to GAGs and epithelial cells and in biofilm formation. Here, we examine the molecular functi...

  16. Substrate availability for long-chain base formation as a regulator of hepatic sphingolipid and cholesterol biosynthesis

    International Nuclear Information System (INIS)

    The de novo biosynthesis of the sphinganine and sphingosine backbones of sphingolipids was studied with isolated rat hepatocytes and established liver cell lines. The rate of incorporation of radiolabel from [14C]-serine by intact cells was half maximal at 0.3 mM, which is similar to the K/sub m/ of the initial enzyme of this pathway and in vivo concentrations of this substrate. Long-chain base biosynthesis was stimulated by another precursor, palmitic acid, but other fatty acids were inhibitory. Hepatocytes isolated from fed and fasted rats had different rates of sphingolipid formation, which may also reflect the relative levels of palmitoyl-CoA. These results established that the availability of the precursors of long-chain base formation, serine and palmitic acid, is a major factor in the regulation of this pathway. Since sphingomyelin biosynthesis could be modified, its relationship to cholesterol metabolism was also examined. Both hepatocytes and cultured liver cells in high serine (0.6mM) had increased incorporation of [14C]-acetate into cholesterol (13%, P < 0.05 and 50%, P < 0.01, respectively). These results indicate that sphingolipid and cholesterol biosynthesis are coordinately regulated, perhaps because these lipids are located in similar membranes and lipoproteins

  17. Transport, boundary physics

    International Nuclear Information System (INIS)

    In this paper the contributions presented at the 18th IAEA Fusion Energy Conference in the field of transport and boundary physics will be summarised with reference to the following distinct issues: H-mode physics, Internal Transport Barrier formation, transport studies, Radiative Improved modes and impurity seeding, divertor and He exhaust, new configurations. (author)

  18. STAT3 Regulates ABCA3 Expression and Influences Lamellar Body Formation in Alveolar Type II Cells

    OpenAIRE

    Matsuzaki, Yohei; Besnard, Valérie; Clark, Jean C.; Xu, Yan; Wert, Susan E.; Ikegami, Machiko; Whitsett, Jeffrey A.

    2007-01-01

    ATP-Binding Cassette A3 (ABCA3) is a lamellar body associated lipid transport protein required for normal synthesis and storage of pulmonary surfactant in type II cells in the alveoli. In this study, we demonstrate that STAT3, activated by IL-6, regulates ABCA3 expression in vivo and in vitro. ABCA3 mRNA and immunostaining were decreased in adult mouse lungs in which STAT3 was deleted from the respiratory epithelium (Stat3Δ/Δ mice). Consistent with the role of STAT3, intratracheal IL-6 induce...

  19. Dimer formation and transcription activation in the sporulation response regulator Spo0A.

    Science.gov (United States)

    Lewis, Richard J; Scott, David J; Brannigan, James A; Ladds, Joanne C; Cervin, Marguerite A; Spiegelman, George B; Hoggett, James G; Barák, Imrich; Wilkinson, Anthony J

    2002-02-15

    The response regulator Spo0A is the master control element in the initiation of sporulation in Bacillus subtilis. Like many other multi-domain response regulators, the latent activity of the effector, C-terminal domain is stimulated by phosphorylation on a conserved aspartic acid residue in the regulatory, N-terminal domain. If a threshold concentration of phosphorylated Spo0A is achieved, the transcription of genes required for sporulation is activated, whereas the genes encoding stationary phase sentinels are repressed, and sporulation proceeds. Despite detailed genetic, biochemical and structural characterisation, it is not understood how the phosphorylation signal in the receiver domain is transduced into DNA binding and transcription activation in the distal effector domain. An obstacle to our understanding of Spo0A function is the uncertainty concerning changes in quaternary structure that accompany phosphorylation. Here we have revisited this question and shown unequivocally that Spo0A forms dimers upon phosphorylation and that the subunit interactions in the dimer are mediated principally by the receiver domain. Purified dimers of two mutants of Spo0A, in which the phosphorylatable aspartic acid residue has been substituted, activate transcription from the spoIIG promoter in vitro, whereas monomers do not. This suggests that dimers represent the activated form of Spo0A. PMID:11851334

  20. Neural cell 3D microtissue formation is marked by cytokines' up-regulation.

    Directory of Open Access Journals (Sweden)

    Yinzhi Lai

    Full Text Available Cells cultured in three dimensional (3D scaffolds as opposed to traditional two-dimensional (2D substrates have been considered more physiologically relevant based on their superior ability to emulate the in vivo environment. Combined with stem cell technology, 3D cell cultures can provide a promising alternative for use in cell-based assays or biosensors in non-clinical drug discovery studies. To advance 3D culture technology, a case has been made for identifying and validating three-dimensionality biomarkers. With this goal in mind, we conducted a transcriptomic expression comparison among neural progenitor cells cultured on 2D substrates, 3D porous polystyrene scaffolds, and as 3D neurospheres (in vivo surrogate. Up-regulation of cytokines as a group in 3D and neurospheres was observed. A group of 13 cytokines were commonly up-regulated in cells cultured in polystyrene scaffolds and neurospheres, suggesting potential for any or a combination from this list to serve as three-dimensionality biomarkers. These results are supportive of further cytokine identification and validation studies with cells from non-neural tissue.

  1. LIGHT REGULATION OF GROWTH AND MELANIN FORMATION IN Inonotus оbliquus (Pers. Pilat

    Directory of Open Access Journals (Sweden)

    N. L. Poyedinok

    2013-04-01

    Full Text Available The study aims to investigate possibilities of using different sources of low-intensity light for the regulation of mycelium growth and melanin synthesis by medicinal mushroom Inonotus obliquus (Pers. Pilat. Studies of the light’s influence on the linear growth, biomass accumulation and melanin synthesis I. obliquus were performed using experimental installations that provide both lasing (coherent light with specified parameters, as well as sources of incoherent light. It has been demonstrated that the greatest stimulating effect took place during the irradiation of mycelium with blue light. It has been found that further realization of photobiological effect is largely dependent on the method of cultivation. Irradiation with laser light within all studied wavelength ranges was more conducive to growth, biomass and melanin accumulation in the mushroom mycelium than incoherent light irradiation within the same wavelength range. Light treatment made it possible to significantly reduce the duration of fermentation. The results of studies allow considering lowintensity light in the visible part of the spectrum as a perspective growth and biosynthetic activity regulator of I. obliquus in the biotechnology of its cultivation.

  2. Matrix Metalloproteinases: Inflammatory Regulators of Cell Behaviors in Vascular Formation and Remodeling

    Directory of Open Access Journals (Sweden)

    Qishan Chen

    2013-01-01

    Full Text Available Abnormal angiogenesis and vascular remodeling contribute to pathogenesis of a number of disorders such as tumor, arthritis, atherosclerosis, restenosis, hypertension, and neurodegeneration. During angiogenesis and vascular remodeling, behaviors of stem/progenitor cells, endothelial cells (ECs, and vascular smooth muscle cells (VSMCs and its interaction with extracellular matrix (ECM play a critical role in the processes. Matrix metalloproteinases (MMPs, well-known inflammatory mediators are a family of zinc-dependent proteolytic enzymes that degrade various components of ECM and non-ECM molecules mediating tissue remodeling in both physiological and pathological processes. MMPs including MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-12, and MT1-MMP, are stimulated and activated by various stimuli in vascular tissues. Once activated, MMPs degrade ECM proteins or other related signal molecules to promote recruitment of stem/progenitor cells and facilitate migration and invasion of ECs and VSMCs. Moreover, vascular cell proliferation and apoptosis can also be regulated by MMPs via proteolytically cleaving and modulating bioactive molecules and relevant signaling pathways. Regarding the importance of vascular cells in abnormal angiogenesis and vascular remodeling, regulation of vascular cell behaviors through modulating expression and activation of MMPs shows therapeutic potential.

  3. REGULATION OF STAR FORMATION RATES IN MULTIPHASE GALACTIC DISKS: NUMERICAL TESTS OF THE THERMAL/DYNAMICAL EQUILIBRIUM MODEL

    International Nuclear Information System (INIS)

    We use vertically resolved numerical hydrodynamic simulations to study star formation and the interstellar medium (ISM) in galactic disks. We focus on outer-disk regions where diffuse H I dominates, with gas surface densities Σ = 3-20 M☉ pc–2 and star-plus-dark matter volume densities ρsd = 0.003-0.5 M☉ pc–3. Star formation occurs in very dense, self-gravitating clouds that form by mergers of smaller cold cloudlets. Turbulence, driven by momentum feedback from supernova events, destroys bound clouds and puffs up the disk vertically. Time-dependent radiative heating (FUV from recent star formation) offsets gas cooling. We use our simulations to test a new theory for self-regulated star formation. Consistent with this theory, the disks evolve to a state of vertical dynamical equilibrium and thermal equilibrium with both warm and cold phases. The range of star formation surface densities and midplane thermal pressures is ΣSFR ∼ 10–4 to 10–2 M☉ kpc–2 yr–1 and Pth/kB ∼ 102 to 104 cm–3 K. In agreement with observations, turbulent velocity dispersions are ∼7 km s–1 and the ratio of the total (effective) to thermal pressure is Ptot/Pth ∼ 4-5, across this whole range (provided shielding is similar to the solar neighborhood). We show that ΣSFR is not well correlated with Σ alone, but rather with Σ√(ρsd), because the vertical gravity from stars and dark matter dominates in outer disks. We also find that ΣSFR has a strong, nearly linear correlation with Ptot, which itself is within ∼13% of the dynamical equilibrium estimate Ptot,DE. The quantitative relationships we find between ΣSFR and the turbulent and thermal pressures show that star formation is highly efficient for energy and momentum production, in contrast to the low efficiency of mass consumption. Star formation rates adjust until the ISM's energy and momentum losses are replenished by feedback within a dynamical time.

  4. Regulation of aggrecanases from the ADAMTS family and aggrecan neoepitope formation during in vitro chondrogenesis of human mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    W Richter

    2012-05-01

    Full Text Available Aggrecanases from the ADAMTS (A Disintegrin And Metalloproteinase with ThromboSpondin motifs family are important therapeutic targets due to their essential role in aggrecan depletion in arthritic diseases. Whether their function is also important for matrix rearrangements during chondrogenesis and thus, cartilage regeneration, is however so far unknown. The aim of this study was to analyse the expression and function of ADAMTS with aggrecanase activity during chondrogenic differentiation of human mesenchymal stem cells (MSCs. Chondrogenic differentiation was induced in bone marrow-derived MSC pellets and expression of COL2A1, aggrecan, ADAMTS1, 4, 5, 9, 16 and furin was followed by quantitative RT-PCR. Formation of the NITEGE (ADAMTS-cleaved and DIPEN (MMP-cleaved aggrecan neoepitopes was detected by immunohistochemistry. While the expression of ADAMTS4, 9, 16 and furin was up-regulated during chondrogenesis, ADAMTS1 and 5 were down-regulated. Despite this regulation of ADAMTS, no formation of NITEGE neoepitopes occurred in MSC pellets, indicating no ADAMTS-induced cleavage of aggrecan. In contrast, MMP-induced cleavage of aggrecan appeared at 14 d after induction of chondrogenesis. Submission of differentiated MSC pellets to IL1β treatment for 3 d resulted in strong upregulation of ADAMTS1, 4 and 5, rapid proteoglycan depletion, and stimulation of ADAMTS-induced but not MMP-induced cleavage of aggrecan. Thus, there is no evidence for ADAMTS-induced aggrecan cleavage during chondrogenesis, but proteoglycan turnover is rapidly inducible under inflammatory signals. Therapeutic aggrecanase inhibition for treatment of arthritic disease may thus not impede regenerative self-healing pathways based on chondrogenesis of local progenitor cells in the joint.

  5. DegQ regulates the production of fengycins and biofilm formation of the biocontrol agent Bacillus subtilis NCD-2.

    Science.gov (United States)

    Wang, Peipei; Guo, Qinggang; Ma, Yinan; Li, Shezeng; Lu, Xiuyun; Zhang, Xiaoyun; Ma, Ping

    2015-09-01

    Bacillus subtilis NCD-2 is an excellent biocontrol agent for tomato gray mold and cotton soil-borne diseases. The fengycin lipopeptides serve as a major role in its biocontrol ability. A previous study revealed that insertion of degQ with the mini-Tn10 transposon decreased the antifungal activity of strain NCD-2 against the growth of Botrytis cinerea. To clarify the regulation of degQ on the production of fengycin, we deleted degQ by in-frame mutagenesis. Compared with the wild-type strain NCD-2, the degQ-null mutant had decreased extracellular protease and cellulase activities as well as antifungal ability against the growth of B. cinerea in vitro. The lipopeptides from the degQ-null mutant also had significantly decreased antifungal activity against B. cinerea in vitro and in vivo. This result was confirmed by the decreased fengycin production in the degQ-null mutant that was detected by fast protein liquid chromatography analysis. Quantitative reverse transcription PCR further demonstrated that degQ positively regulated the expression of the fengycin synthetase gene. In addition, the degQ-null mutant also had a flatter colony phenotype and significantly decreased biofilm formation ability relative to the wild-type strain. All of those characteristics from degQ-null mutant could be restored to the strain NCD-2 wild-type level by complementation of intact degQ in the mutant. Therefore, DegQ may be an important regulator of fengycin production and biofilm formation in B. subtilis NCD-2. PMID:26302846

  6. Class I PI-3-Kinase Signaling Is Critical for Bone Formation Through Regulation of SMAD1 Activity in Osteoblasts.

    Science.gov (United States)

    Gámez, Beatriz; Rodríguez-Carballo, Edgardo; Graupera, Mariona; Rosa, José Luis; Ventura, Francesc

    2016-08-01

    Bone formation and homeostasis is carried out by osteoblasts, whose differentiation and activity are regulated by osteogenic signaling networks. A central mediator of these inputs is the lipid kinase phosphatidylinositol 3-kinase (PI3K). However, at present, there are no data on the specific role of distinct class IA PI3K isoforms in bone biology. Here, we performed osteoblast-specific deletion in mice to show that both p110α and p110β isoforms are required for survival and differentiation and function of osteoblasts and thereby control bone formation and postnatal homeostasis. Impaired osteogenesis arises from increased GSK3 activity and a depletion of SMAD1 protein levels in PI3K-deficient osteoblasts. Accordingly, pharmacological inhibition of GSK3 activity or ectopic expression of SMAD1 or SMAD5 normalizes bone morphogenetic protein (BMP) transduction and osteoblast differentiation. Together, these results identify the PI3K-GSK3-SMAD1 axis as a central node integrating multiple signaling networks that govern bone formation and homeostasis. © 2016 American Society for Bone and Mineral Research. PMID:26896753

  7. Integration of a Notch-dependent mesenchymal gene program and Bmp2-driven cell invasiveness regulates murine cardiac valve formation.

    Science.gov (United States)

    Luna-Zurita, Luis; Prados, Belén; Grego-Bessa, Joaquim; Luxán, Guillermo; del Monte, Gonzalo; Benguría, Alberto; Adams, Ralf H; Pérez-Pomares, José María; de la Pompa, José Luis

    2010-10-01

    Cardiac valve formation is crucial for embryonic and adult heart function. Valve malformations constitute the most common congenital cardiac defect, but little is known about the molecular mechanisms regulating valve formation and homeostasis. Here, we show that endocardial Notch1 and myocardial Bmp2 signal integration establish a valve-forming field between 2 chamber developmental domains. Patterning occurs through the activation of endocardial epithelial-to-mesenchymal transition (EMT) exclusively in prospective valve territories. Mice with constitutive endocardial Notch1 activity ectopically express Hey1 and Heyl. They also display an activated mesenchymal gene program in ventricles and a partial (noninvasive) EMT in vitro that becomes invasive upon BMP2 treatment. Snail1, TGF-β2, or Notch1 inhibition reduces BMP2-induced ventricular transformation and invasion, whereas BMP2 treatment inhibits endothelial Gsk3β, stabilizing Snail1 and promoting invasiveness. Integration of Notch and Bmp2 signals is consistent with Notch1 signaling being attenuated after myocardial Bmp2 deletion. Notch1 activation in myocardium extends Hey1 expression to nonchamber myocardium, represses Bmp2, and impairs EMT. In contrast, Notch deletion abrogates endocardial Hey gene transcription and extends Bmp2 expression to the ventricular endocardium. This embryonic Notch1-Bmp2-Snail1 relationship may be relevant in adult valve disease, in which decreased NOTCH signaling causes valve mesenchyme cell formation, fibrosis, and calcification. PMID:20890042

  8. Pathways Regulating Spheroid Formation of Human Follicular Thyroid Cancer Cells under Simulated Microgravity Conditions: A Genetic Approach

    Science.gov (United States)

    Riwaldt, Stefan; Bauer, Johann; Wehland, Markus; Slumstrup, Lasse; Kopp, Sascha; Warnke, Elisabeth; Dittrich, Anita; Magnusson, Nils E.; Pietsch, Jessica; Corydon, Thomas J.; Infanger, Manfred; Grimm, Daniela

    2016-01-01

    Microgravity induces three-dimensional (3D) growth in numerous cell types. Despite substantial efforts to clarify the underlying mechanisms for spheroid formation, the precise molecular pathways are still not known. The principal aim of this paper is to compare static 1g-control cells with spheroid forming (MCS) and spheroid non-forming (AD) thyroid cancer cells cultured in the same flask under simulated microgravity conditions. We investigated the morphology and gene expression patterns in human follicular thyroid cancer cells (UCLA RO82-W-1 cell line) after a 24 h-exposure on the Random Positioning Machine (RPM) and focused on 3D growth signaling processes. After 24 h, spheroid formation was observed in RPM-cultures together with alterations in the F-actin cytoskeleton. qPCR indicated more changes in gene expression in MCS than in AD cells. Of the 24 genes analyzed VEGFA, VEGFD, MSN, and MMP3 were upregulated in MCS compared to 1g-controls, whereas ACTB, ACTA2, KRT8, TUBB, EZR, RDX, PRKCA, CAV1, MMP9, PAI1, CTGF, MCP1 were downregulated. A pathway analysis revealed that the upregulated genes code for proteins, which promote 3D growth (angiogenesis) and prevent excessive accumulation of extracellular proteins, while genes coding for structural proteins are downregulated. Pathways regulating the strength/rigidity of cytoskeletal proteins, the amount of extracellular proteins, and 3D growth may be involved in MCS formation. PMID:27070589

  9. Pathways Regulating Spheroid Formation of Human Follicular Thyroid Cancer Cells under Simulated Microgravity Conditions: A Genetic Approach

    Directory of Open Access Journals (Sweden)

    Stefan Riwaldt

    2016-04-01

    Full Text Available Microgravity induces three-dimensional (3D growth in numerous cell types. Despite substantial efforts to clarify the underlying mechanisms for spheroid formation, the precise molecular pathways are still not known. The principal aim of this paper is to compare static 1g-control cells with spheroid forming (MCS and spheroid non-forming (AD thyroid cancer cells cultured in the same flask under simulated microgravity conditions. We investigated the morphology and gene expression patterns in human follicular thyroid cancer cells (UCLA RO82-W-1 cell line after a 24 h-exposure on the Random Positioning Machine (RPM and focused on 3D growth signaling processes. After 24 h, spheroid formation was observed in RPM-cultures together with alterations in the F-actin cytoskeleton. qPCR indicated more changes in gene expression in MCS than in AD cells. Of the 24 genes analyzed VEGFA, VEGFD, MSN, and MMP3 were upregulated in MCS compared to 1g-controls, whereas ACTB, ACTA2, KRT8, TUBB, EZR, RDX, PRKCA, CAV1, MMP9, PAI1, CTGF, MCP1 were downregulated. A pathway analysis revealed that the upregulated genes code for proteins, which promote 3D growth (angiogenesis and prevent excessive accumulation of extracellular proteins, while genes coding for structural proteins are downregulated. Pathways regulating the strength/rigidity of cytoskeletal proteins, the amount of extracellular proteins, and 3D growth may be involved in MCS formation.

  10. Pathways Regulating Spheroid Formation of Human Follicular Thyroid Cancer Cells under Simulated Microgravity Conditions: A Genetic Approach.

    Science.gov (United States)

    Riwaldt, Stefan; Bauer, Johann; Wehland, Markus; Slumstrup, Lasse; Kopp, Sascha; Warnke, Elisabeth; Dittrich, Anita; Magnusson, Nils E; Pietsch, Jessica; Corydon, Thomas J; Infanger, Manfred; Grimm, Daniela

    2016-01-01

    Microgravity induces three-dimensional (3D) growth in numerous cell types. Despite substantial efforts to clarify the underlying mechanisms for spheroid formation, the precise molecular pathways are still not known. The principal aim of this paper is to compare static 1g-control cells with spheroid forming (MCS) and spheroid non-forming (AD) thyroid cancer cells cultured in the same flask under simulated microgravity conditions. We investigated the morphology and gene expression patterns in human follicular thyroid cancer cells (UCLA RO82-W-1 cell line) after a 24 h-exposure on the Random Positioning Machine (RPM) and focused on 3D growth signaling processes. After 24 h, spheroid formation was observed in RPM-cultures together with alterations in the F-actin cytoskeleton. qPCR indicated more changes in gene expression in MCS than in AD cells. Of the 24 genes analyzed VEGFA, VEGFD, MSN, and MMP3 were upregulated in MCS compared to 1g-controls, whereas ACTB, ACTA2, KRT8, TUBB, EZR, RDX, PRKCA, CAV1, MMP9, PAI1, CTGF, MCP1 were downregulated. A pathway analysis revealed that the upregulated genes code for proteins, which promote 3D growth (angiogenesis) and prevent excessive accumulation of extracellular proteins, while genes coding for structural proteins are downregulated. Pathways regulating the strength/rigidity of cytoskeletal proteins, the amount of extracellular proteins, and 3D growth may be involved in MCS formation. PMID:27070589

  11. Magnetically Regulated Star Formation in 3D: The Case of Taurus Molecular Cloud Complex

    CERN Document Server

    Nakamura, Fumitaka

    2008-01-01

    We carry out three-dimensional MHD simulations of star formation in turbulent, magnetized clouds, including ambipolar diffusion and feedback from protostellar outflows. The calculations focus on relatively diffuse clouds threaded by a strong magnetic field capable of resisting severe tangling by turbulent motions and retarding global gravitational contraction in the cross-field direction. They are motivated by observations of the Taurus molecular cloud complex (and, to a lesser extent, Pipe Nebula), which shows an ordered large-scale magnetic field, as well as elongated condensations that are generally perpendicular to the large-scale field. We find that stars form in earnest in such clouds when enough material has settled gravitationally along the field lines that the mass-to-flux ratios of the condensations approach the critical value. Only a small fraction (of order 1% or less) of the nearly magnetically-critical, condensed material is turned into stars per local free-fall time, however. The slow star form...

  12. Boundary Layer

    Science.gov (United States)

    Loitsianskii. L. G.

    1956-01-01

    The fundamental, practically the most important branch of the modern mechanics of a viscous fluid or a gas, is that branch which concerns itself with the study of the boundary layer. The presence of a boundary layer accounts for the origin of the resistance and lift force, the breakdown of the smooth flow about bodies, and other phenomena that are associated with the motion of a body in a real fluid. The concept of boundary layer was clearly formulated by the founder of aerodynamics, N. E. Joukowsky, in his well-known work "On the Form of Ships" published as early as 1890. In his book "Theoretical Foundations of Air Navigation," Joukowsky gave an account of the most important properties of the boundary layer and pointed out the part played by it in the production of the resistance of bodies to motion. The fundamental differential equations of the motion of a fluid in a laminar boundary layer were given by Prandtl in 1904; the first solutions of these equations date from 1907 to 1910. As regards the turbulent boundary layer, there does not exist even to this day any rigorous formulation of this problem because there is no closed system of equations for the turbulent motion of a fluid. Soviet scientists have done much toward developing a general theory of the boundary layer, and in that branch of the theory which is of greatest practical importance at the present time, namely the study of the boundary layer at large velocities of the body in a compressed gas, the efforts of the scientists of our country have borne fruit in the creation of a new theory which leaves far behind all that has been done previously in this direction. We shall herein enumerate the most important results by Soviet scientists in the development of the theory of the boundary layer.

  13. In vitro approach to the mechanics of lipid membrane area regulation: vesicle absorption and tube formation

    Science.gov (United States)

    Staykova, Margarita; Holmes, Douglas; Read, Clarke; Stone, Howard A.

    2011-03-01

    We have designed an experimental approach that allows us to study the response of supported lipid bilayers to cycles of biaxial expansion and compression. We observed that the bilayer effectively adjusts its area during dilatational or compressive strains in order to reduce its tension. For example, if there is a sufficient lipid reservoir in the form of attached vesicles, then a lipid bilayer may accommodate strains tens of times larger than the critical strain for rupture by expanding its area. Additionally, upon compression the bilayer reduces its area by expelling lipid tubes out of its plane. These observations offer new insights into how cells regulate their surface area in response to various mechanical stimuli, i.e. during physiological volume changes, locomotion, cyclic expansion and compression of the uro- and the alveolar- epithelium, etc.

  14. The Impact of Immune System in Regulating Bone Metastasis Formation by Osteotropic Tumors

    Directory of Open Access Journals (Sweden)

    Lucia D’Amico

    2015-01-01

    Full Text Available Bone metastases are frequent and debilitating consequence for many tumors, such as breast, lung, prostate, and kidney cancer. Many studies report the importance of the immune system in the pathogenesis of bone metastasis. Indeed, bone and immune system are strictly linked to each other because bone regulates the hematopoietic stem cells from which all cells of the immune system derive, and many immunoregulatory cytokines influence the fate of bone cells. Furthermore, both cytokines and factors produced by immune and bone cells promote the growth of tumor cells in bone, contributing to supporting the vicious cycle of bone metastasis. This review summarizes the current knowledge on the interactions among bone, immune, and tumor cells aiming to provide an overview of the osteoimmunology field in bone metastasis from solid tumors.

  15. Evidence of stratabound liquefaction in the formation of fractured topographic margins, cone chains and pit catenas along the Martian Dichotomy Boundary and in Isidis Planitia, Mars.

    Science.gov (United States)

    Gallagher, C.; Balme, M. R.

    2012-04-01

    On the low-lying plains along much of the Martian Dichotomy Boundary (MDB) and in the Isidis impact basin, cones and curving chains of cones, referred to as thumbprint terrain (TPT), are common. In the same settings, pit chains (catenas) occur in orthogonal to curving and conchoidal fracture sets between mesa-like crustal blocks, generally at or near topographic margins. Many of the fractures consist of linked pits rather than simple propagated cracks. These assemblages are often associated with the more disaggregated populations of blocks comprising chaos terrain. We show that the local planimetric arrangement of the cone chains, fractures and pit catenas is strikingly similar in both shape and scale, including lateral separation, length, longitudinal slope and radius of curvature. The summits of cones tend to be closely accordant along individual cone chains. Neighbouring cone chains tend to be mutually accordant on low gradient basin surfaces but generally stepped en echelon closer to the fractured basin margins. Similarly, the crustal blocks (including very isolated block sets) are often mutually stepped, and fractures between these en echelon blocks tend to be very close to horizontal. Hence, many cone chains, fractures and pit catenas in fractures share the property of being arranged along strike. They diverge morphologically by the cone chains being positive forms separated by narrow gulfs but the pit catenas being negative forms separated by planar blocks. All of these characteristics point to the possibility that the arcuate cone chains and the arcuate pit catenas have a common origin. In particular, we hypothesise that the cone chains characteristic of TPT along the MDB and in Isidis are filled, indurated and then exhumed pit catenas revealed by the stripping-away of intervening blocks [cf. 1]. Many other surfaces on Mars are pervaded by pits and pit catenas, with evidence of former water flow through the catenas suggesting that ground-ice thaw played a

  16. Strain Localization in Thin Films of Bi(Fe,Mn)O3 Due to the Formation of Stepped Mn(4+)-Rich Antiphase Boundaries.

    Science.gov (United States)

    MacLaren, I; Sala, B; Andersson, S M L; Pennycook, T J; Xiong, J; Jia, Q X; Choi, E-M; MacManus-Driscoll, J L

    2015-12-01

    The atomic structure and chemistry of thin films of Bi(Fe,Mn)O3 (BFMO) films with a target composition of Bi2FeMnO6 on SrTiO3 are studied using scanning transmission electron microscopy imaging and electron energy loss spectroscopy. It is shown that Mn(4+)-rich antiphase boundaries are locally nucleated right at the film substrate and then form stepped structures that are approximately pyramidal in three dimensions. These have the effect of confining the material below the pyramids in a highly strained state with an out-of-plane lattice parameter close to 4.1 Å. Outside the area enclosed by the antiphase boundaries, the out-of-plane lattice parameter is much closer to bulk values for BFMO. This suggests that to improve the crystallographic perfection of the films whilst retaining the strain state through as much of the film as possible, ways need to be found to prevent nucleation of the antiphase boundaries. Since the antiphase boundaries seem to form from the interaction of Mn with the Ti in the substrate, one route to perform this would be to grow a thin buffer layer of pure BiFeO3 on the SrTiO3 substrate to minimise any Mn-Ti interactions. PMID:26474888

  17. Galaxy Zoo and ALFALFA: Atomic Gas and the Regulation of Star Formation in Barred Disc Galaxies

    CERN Document Server

    Masters, Karen L; Haynes, Martha P; Keel, William C; Lintott, Chris; Simmons, Brooke; Skibba, Ramin; Bamford, Steven; Giovanelli, Riccardo; Schawinski, Kevin

    2012-01-01

    We study the observed correlation between atomic gas content and the likelihood of hosting a large scale bar in a sample of 2090 disc galaxies. Such a test has never been done before on this scale. We use data on morphologies from the Galaxy Zoo project and information on the galaxies' HI content from the ALFALFA blind HI survey. Our main result is that the bar fraction is significantly lower among gas rich disc galaxies than gas poor ones. This is not explained by known trends for more massive (stellar) and redder disc galaxies to host more bars and have lower gas fractions: we still see at fixed stellar mass a residual correlation between gas content and bar fraction. We discuss three possible causal explanations: (1) bars in disc galaxies cause atomic gas to be used up more quickly, (2) increasing the atomic gas content in a disc galaxy inhibits bar formation, and (3) bar fraction and gas content are both driven by correlation with environmental effects (e.g. tidal triggering of bars, combined with strangu...

  18. Boundary Spanning

    DEFF Research Database (Denmark)

    Zølner, Mette

    The paper explores how locals span boundaries between corporate and local levels. The aim is to better comprehend potentialities and challenges when MNCs draws on locals’ culture specific knowledge. The study is based on an in-depth, interpretive case study of boundary spanning by local actors in...... approach with pattern matching is a way to shed light on the tacit local knowledge that organizational actors cannot articulate and that an exclusively inductive research is not likely to unveil....

  19. CREB Regulates Experience-Dependent Spine Formation and Enlargement in Mouse Barrel Cortex

    Directory of Open Access Journals (Sweden)

    Annabella Pignataro

    2015-01-01

    Full Text Available Experience modifies synaptic connectivity through processes that involve dendritic spine rearrangements in neuronal circuits. Although cAMP response element binding protein (CREB has a key function in spines changes, its role in activity-dependent rearrangements in brain regions of rodents interacting with the surrounding environment has received little attention so far. Here we studied the effects of vibrissae trimming, a widely used model of sensory deprivation-induced cortical plasticity, on processes associated with dendritic spine rearrangements in the barrel cortex of a transgenic mouse model of CREB downregulation (mCREB mice. We found that sensory deprivation through prolonged whisker trimming leads to an increased number of thin spines in the layer V of related barrel cortex (Contra in wild type but not mCREB mice. In the barrel field controlling spared whiskers (Ipsi, the same trimming protocol results in a CREB-dependent enlargement of dendritic spines. Last, we demonstrated that CREB regulates structural rearrangements of synapses that associate with dynamic changes of dendritic spines. Our findings suggest that CREB plays a key role in dendritic spine dynamics and synaptic circuits rearrangements that account for new brain connectivity in response to changes in the environment.

  20. Gravity-dependent regulation of red light induced moss protonemata branching and gametophore bud formation

    Science.gov (United States)

    Ripetskyj, R. T.; Kit, N. A.

    Isolated leafy shoots of the moss Pottia intermedia positioned horizontally on the agar surface in vertically oriented petri dishes regenerate unbranching negatively gravitropic protonemata on upper side of the regenerant. Gravity determines the site of regeneration not the process itself. White light of low intensity unsufficient to induce positive phototropism of dark-grown protonemata can, however, provoke their branching and gametophore bud formation (Ripetskyj et al., 1998; 1999). The presented experiments have been carried out with red light in Biological Research in Canisters/Light Emitting Diode (BRIC/LED) hardware developed at Kennedy Space Center, USA. Seven-day-old dark-grown negatively gravitropic secondary P. intermedia protonemata were positioned differently with respect to gravity vector and to the source of red light of low, 1 or 2 μ mol\\cdot m-2\\cdot s-1, intensities. The light induced intensive branching of the protonemata and gametophore bud formation initiation site of both processes as well as the direction of growth of branches and buds being depent on the position of protonemata with respect to gravity and light vectors. Vertically positioned, i.e. ungravistimulated, dark grown protonemata illuminated from one side with red light of 2 μ mol\\cdot m-2\\cdot s-1 intensity produced 96,9 ± 2,2% of side branches and buds growing directly towards the light source from the lit protonema side. Horizontally disposed protonemata irradiated from below with red light of the same intensity regenerate 31,7 ± 3,9% of branches and buds on the upper, i.e. shaded protonemata side, the upward growth of which should undoubtedly be determined by gravity. In vertically disposed protonemata illuminated with red light of 1 μ mol\\cdot m-2\\cdot s-1 intensity from aside 31,9 ± 5,5% of side branches and buds arised on shaded protonema side and grew away from the light. Illumination of the protonemata in horizontal position from below increased the number of

  1. Constitutive formation of an RXFP1-signalosome: a novel paradigm in GPCR function and regulation.

    Science.gov (United States)

    Halls, Michelle L

    2012-03-01

    The classical second messenger cAMP is important in diverse physiological processes, where its spatial and temporal compartmentalization allows precise control over multiple cellular events. Within this context, G-protein-coupled receptors (GPCRs) govern specialized pools of cAMP, which are functionally specific for the unique cellular effects attributed to a particular system. The relaxin receptor, RXFP1, is a GPCR that exerts pleiotropic physiological effects including a potent anti-fibrotic response, increased cancer metastases, and has efficacy as a vasodilator in heart failure. On a cellular level, relaxin stimulation of RXFP1 results in the activation of multiple G-protein pathways affecting cAMP accumulation. Specificity and diversity in the cAMP signal generated by RXFP1 is controlled by differential G-protein coupling dependent upon the background of cellular expression, and cAMP compartmentalization. Further complexity in cAMP signalling results from the constitutive assembly of an RXFP1-signalosome, which specifically responds to low concentrations of relaxin, and activates a distinct cAMP pathway. The RXFP1-signalosome is a higher-order protein complex that facilitates receptor sensitivity to attomolar concentration of peptide, exhibits constitutive activity and dual coupling to G-proteins and β-arrestins and reveals a concentration-biased agonism mediated by relaxin. The specific and directed formation of GPCR-centered signalosomes allows an even greater spatial and temporal control of cAMP, thus rationalizing the considerable physiological scope of this ubiquitous second messenger. PMID:21557732

  2. Increased abscess formation and defective chemokine regulation in CREB transgenic mice.

    Directory of Open Access Journals (Sweden)

    Andy Y Wen

    Full Text Available Cyclic AMP-response element-binding protein (CREB is a transcription factor implicated in growth factor-dependent cell proliferation and survival, glucose homeostasis, spermatogenesis, circadian rhythms, and synaptic plasticity associated with memory. To study the phenotype of CREB overexpression in vivo, we generated CREB transgenic (TG mice in which a myeloid specific hMRP8 promoter drives CREB expression. CREB TG mice developed spontaneous skin abscesses more frequently than wild type (WT mice. To understand the role of CREB in myeloid function and innate immunity, chemokine expression in bone marrow derived macrophages (BMDMs from CREB TG mice were compared with BMDMs from WT mice. Our results demonstrated decreased Keratinocyte-derived cytokine (KC in CREB TG BMDMs but not TNFα protein production in response to lipid A (LPA. In addition, mRNA expression of KC and IL-1β (Interleukin-1β was decreased in CREB TG BMDMs; however, there was no difference in the mRNA expression of TNFα, MCP-1, IL-6 and IL-12p40. The mRNA expression of IL-1RA and IL-10 was decreased in response to LPA. Nuclear factor kappa B (NFκB expression and a subset of its target genes were upregulated in CREB TG mouse BMDMs. Although neutrophil migration was the same in both CREB TG and WT mice, Nicotinamide adenine dinucleotide phosphate (NADPH oxidase activity was significantly increased in neutrophils from CREB TG mice. Taken together, CREB overexpression in myeloid cells results in increased abscess formation in vivo and aberrant cytokine and chemokine response, and neutrophil function in vitro.

  3. Effect of VN precipitates on formation of grain boundary and intragranular ferrite in a high N-V bearing steel; V-N tenkako no ryukai oyobi ryunai ferrite hentai ni oyobosu austenite chu no VN sekishutsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Omori, A.; Oi, K.; Kawabata, F.; Amano, K. [Kawasaki Steel Corp., Tokyo (Japan)

    1998-11-01

    The enhancement of ferrite nucleation owing to vanadium nitride (VN) precipitated in the austenite phase was studied for a 0.14%C- 1.45%Mn-0.06%V-0.009%N steel and the isothermal ferrite transformation behavior associated with VN precipitation was also quantitatively discussed. Vanadium nitrides precipitate on the austenite grain boundary in preference to the grain interior and increase the density of grain boundary ferrites. On the other hand, VN precipitates in austenite grain interior are less effective to intragranular ferrite nucleation. The calculation based on the classical nucleation theory shows that the activation energy of VN precipitates for a critical ferrite nucleus formation is one-fifth lower than that in case of no precipitate. The ferrite nucleation potency of VN precipitates is kept high even in higher temperature range above 700degreeC. (author)

  4. Solvent Role in the Formation of Electric Double Layers with Surface Charge Regulation: A Bystander or a Key Participant?

    Science.gov (United States)

    Fleharty, Mark E.; van Swol, Frank; Petsev, Dimiter N.

    2016-01-01

    The charge formation at interfaces involving electrolyte solutions is due to the chemical equilibrium between the surface reactive groups and the potential determining ions in the solution (i.e., charge regulation). In this Letter we report our findings that this equilibrium is strongly coupled to the precise molecular structure of the solution near the charged interface. The neutral solvent molecules dominate this structure due to their overwhelmingly large number. Treating the solvent as a structureless continuum leads to a fundamentally inadequate physical picture of charged interfaces. We show that a proper account of the solvent effect leads to an unexpected and complex system behavior that is affected by the molecular and ionic excluded volumes and van der Waals interactions.

  5. Regulation of biofilm formation and cellular buoyancy through modulating intracellular cyclic di-GMP levels in engineered cyanobacteria.

    Science.gov (United States)

    Agostoni, Marco; Waters, Christopher M; Montgomery, Beronda L

    2016-02-01

    The second messenger cyclic dimeric (3'→5') GMP (cyclic di-GMP or c-di-GMP) has been implicated in the transition between motile and sessile lifestyles in bacteria. In this study, we demonstrate that biofilm formation, cellular aggregation or flocculation, and cellular buoyancy are under the control of c-di-GMP in Synechocystis sp. PCC 6803 (Synechocystis) and Fremyella diplosiphon. Synechocystis is a unicellular cyanobacterium and displays lower levels of c-di-GMP; F. diplosiphon is filamentous and displays higher intracellular c-di-GMP levels. We transformed Synechocystis and F. diplosiphon with a plasmid for constitutive expression of genes encoding diguanylate cylase (DGC) and phosphodiesterase (PDE) proteins from Vibrio cholerae or Escherichia coli, respectively. These engineered strains allowed us to modulate intracellular c-di-GMP levels. Biofilm formation and cellular deposition were induced in the DGC-expressing Synechocystis strain which exhibited high intracellular levels of c-di-GMP; whereas strains expressing PDE in Synechocystis and F. diplosiphon to drive low intracellular levels of c-di-GMP exhibited enhanced cellular buoyancy. In addition, the PDE-expressing F. diplosiphon strain showed elevated chlorophyll levels. These results imply roles for coordinating c-di-GMP homeostasis in regulating native cyanobacterial phenotypes. Engineering exogenous DGC or PDE proteins to regulate intracellular c-di-GMP levels represents an effective tool for uncovering cryptic phenotypes or modulating phenotypes in cyanobacteria for practical applications in biotechnology applicable in photobioreactors and in green biotechnologies, such as energy-efficient harvesting of cellular biomass or the treatment of metal-containing wastewaters. PMID:26192200

  6. Vitamin D3 regulates the formation and degradation of gap junctions in androgen-responsive human prostate cancer cells.

    Directory of Open Access Journals (Sweden)

    Linda Kelsey

    Full Text Available 1α-25(OH2 vitamin D3 (1-25D, an active hormonal form of Vitamin D3, is a well-known chemopreventive and pro-differentiating agent. It has been shown to inhibit the growth of several prostate cancer cell lines. Gap junctions, formed of proteins called connexins (Cx, are ensembles of cell-cell channels, which permit the exchange of small growth regulatory molecules between adjoining cells. Cell-cell communication mediated by gap junctional channels is an important homeostatic control mechanism for regulating cell growth and differentiation. We have investigated the effect of 1-25D on the formation and degradation of gap junctions in an androgen-responsive prostate cancer cell line, LNCaP, which expresses retrovirally-introduced Cx32. Connexin32 is expressed by the luminal and well-differentiated cells of normal prostate and prostate tumors. Our results document that 1-25D enhances the expression of Cx32 and its subsequent assembly into gap junctions. Our results further show that 1-25D prevents androgen-regulated degradation of Cx32, post-translationally, independent of androgen receptor (AR-mediated signaling. Finally, our findings document that formation of gap junctions sensitizes Cx32-expressing LNCaP cells to the growth inhibitory effects of 1-25D and alters their morphology. These findings suggest that the growth-inhibitory effects of 1-25D in LNCaP cells may be related to its ability to modulate the assembly of Cx32 into gap junctions.

  7. The effects of formative assessment on student self-regulation, motivational beliefs, and achievement in elementary science

    Science.gov (United States)

    King, Melissa Digennaro

    Goals 2000 set forth a bold vision for U.S. students: they would be "first in the world in science and mathematics" by the year 2000. Performance indicators such as the TIMSS-R (1999) and NAEP (2000) reports suggest that U.S. students have not yet reached that goal. This study intended to learn how specific assessment strategies might contribute to improved student performance in science. This quasi-experimental study investigated the effects of formative assessment with reflection on students' motivational beliefs, self-regulatory skills, and achievement in elementary science. The study aimed to find out whether and how classroom applications of formative assessment during science instruction might influence fifth-grade students' attitudes and self-perceptions about science learning, self-regulatory learning behaviors, and achievement. To explore the effects of the assessment intervention, the study utilized a mixed methods approach involving quantitative and qualitative investigations of treatment and control groups during a four-week intervention period. Quantitative measures included student self-report surveys administered pre- and post-treatment and an end-of-unit science test. Qualitative measures included classroom observations, student interviews (post-treatment), and a teacher interview (post-treatment). Findings indicated that the fifth-grade students in this study had positive attitudes toward science and high levels of self-efficacy for science. Results suggested that these elementary students employed a wide variety of cognitive and metacognitive strategies to support science learning. Findings revealed that these fifth graders believed formative assessment with reflection was beneficial for science learning outcomes. Research results did not show that the formative assessment intervention contributed to significant differences between treatment and control groups. However, the data revealed different levels of academic achievement and self-regulation

  8. Palynology of the Lost Branch Formation of Kansas - new insights on the major floral transition at the Middle-Upper Pennsylvanian boundary

    Energy Technology Data Exchange (ETDEWEB)

    Peppers, R.A. [Illinois State Geological Survey, Champaign, IL (United States)

    1997-12-01

    Palynological assemblages from two outcrops of the upper part of the Memorial Formation, the Lost Branch Formation and the overlying Hepler unit in Kansas, were examined to discover which stratigraphic interval marks the change from the lycopod-dominated coal swamp floras of Middle Pennylsvanian (Westphalian D) age to the fern-dominated coal swamp floras of Late Pennsylvanian (Stephanian) age.

  9. FAM83H and casein kinase I regulate the organization of the keratin cytoskeleton and formation of desmosomes.

    Science.gov (United States)

    Kuga, Takahisa; Sasaki, Mitsuho; Mikami, Toshinari; Miake, Yasuo; Adachi, Jun; Shimizu, Maiko; Saito, Youhei; Koura, Minako; Takeda, Yasunori; Matsuda, Junichiro; Tomonaga, Takeshi; Nakayama, Yuji

    2016-01-01

    FAM83H is essential for the formation of dental enamel because a mutation in the FAM83H gene causes amelogenesis imperfecta (AI). We previously reported that the overexpression of FAM83H often occurs and disorganizes the keratin cytoskeleton in colorectal cancer cells. We herein show that FAM83H regulates the organization of the keratin cytoskeleton and maintains the formation of desmosomes in ameloblastoma cells. FAM83H is expressed and localized on keratin filaments in human ameloblastoma cell lines and in mouse ameloblasts and epidermal germinative cells in vivo. FAM83H shows preferential localization to keratin filaments around the nucleus that often extend to cell-cell junctions. Alterations in the function of FAM83H by its overexpression, knockdown, or an AI-causing truncated mutant prevent the proper organization of the keratin cytoskeleton in ameloblastoma cells. Furthermore, the AI-causing mutant prevents desmosomal proteins from being localized to cell-cell junctions. The effects of the AI-causing mutant depend on its binding to and possible inhibition of casein kinase I (CK-1). The suppression of CK-1 by its inhibitor, D4476, disorganizes the keratin cytoskeleton. Our results suggest that AI caused by the FAM83H mutation is mediated by the disorganization of the keratin cytoskeleton and subsequent disruption of desmosomes in ameloblasts. PMID:27222304

  10. FAM83H and casein kinase I regulate the organization of the keratin cytoskeleton and formation of desmosomes

    Science.gov (United States)

    Kuga, Takahisa; Sasaki, Mitsuho; Mikami, Toshinari; Miake, Yasuo; Adachi, Jun; Shimizu, Maiko; Saito, Youhei; Koura, Minako; Takeda, Yasunori; Matsuda, Junichiro; Tomonaga, Takeshi; Nakayama, Yuji

    2016-01-01

    FAM83H is essential for the formation of dental enamel because a mutation in the FAM83H gene causes amelogenesis imperfecta (AI). We previously reported that the overexpression of FAM83H often occurs and disorganizes the keratin cytoskeleton in colorectal cancer cells. We herein show that FAM83H regulates the organization of the keratin cytoskeleton and maintains the formation of desmosomes in ameloblastoma cells. FAM83H is expressed and localized on keratin filaments in human ameloblastoma cell lines and in mouse ameloblasts and epidermal germinative cells in vivo. FAM83H shows preferential localization to keratin filaments around the nucleus that often extend to cell-cell junctions. Alterations in the function of FAM83H by its overexpression, knockdown, or an AI-causing truncated mutant prevent the proper organization of the keratin cytoskeleton in ameloblastoma cells. Furthermore, the AI-causing mutant prevents desmosomal proteins from being localized to cell-cell junctions. The effects of the AI-causing mutant depend on its binding to and possible inhibition of casein kinase I (CK-1). The suppression of CK-1 by its inhibitor, D4476, disorganizes the keratin cytoskeleton. Our results suggest that AI caused by the FAM83H mutation is mediated by the disorganization of the keratin cytoskeleton and subsequent disruption of desmosomes in ameloblasts. PMID:27222304

  11. MEG3 long noncoding RNA regulates the TGF-β pathway genes through formation of RNA-DNA triplex structures.

    Science.gov (United States)

    Mondal, Tanmoy; Subhash, Santhilal; Vaid, Roshan; Enroth, Stefan; Uday, Sireesha; Reinius, Björn; Mitra, Sanhita; Mohammed, Arif; James, Alva Rani; Hoberg, Emily; Moustakas, Aristidis; Gyllensten, Ulf; Jones, Steven J M; Gustafsson, Claes M; Sims, Andrew H; Westerlund, Fredrik; Gorab, Eduardo; Kanduri, Chandrasekhar

    2015-01-01

    Long noncoding RNAs (lncRNAs) regulate gene expression by association with chromatin, but how they target chromatin remains poorly understood. We have used chromatin RNA immunoprecipitation-coupled high-throughput sequencing to identify 276 lncRNAs enriched in repressive chromatin from breast cancer cells. Using one of the chromatin-interacting lncRNAs, MEG3, we explore the mechanisms by which lncRNAs target chromatin. Here we show that MEG3 and EZH2 share common target genes, including the TGF-β pathway genes. Genome-wide mapping of MEG3 binding sites reveals that MEG3 modulates the activity of TGF-β genes by binding to distal regulatory elements. MEG3 binding sites have GA-rich sequences, which guide MEG3 to the chromatin through RNA-DNA triplex formation. We have found that RNA-DNA triplex structures are widespread and are present over the MEG3 binding sites associated with the TGF-β pathway genes. Our findings suggest that RNA-DNA triplex formation could be a general characteristic of target gene recognition by the chromatin-interacting lncRNAs. PMID:26205790

  12. Vertical Equilibrium, Energetics, and Star Formation Rates in Magnetized Galactic Disks Regulated by Momentum Feedback from Supernovae

    CERN Document Server

    Kim, Chang-Goo

    2015-01-01

    Recent hydrodynamic (HD) simulations have shown that galactic disks evolve to reach well-defined statistical equilibrium states. The star formation rate (SFR) self-regulates until energy injection by star formation feedback balances dissipation and cooling in the interstellar medium (ISM), and provides vertical pressure support to balance gravity. In this paper, we extend our previous models to allow for a range of initial magnetic field strengths and configurations, utilizing three-dimensional, magnetohydrodynamic (MHD) simulations. We show that a quasi-steady equilibrium state is established as rapidly for MHD as for HD models unless the initial magnetic field is very strong or very weak, which requires more time to reach saturation. Remarkably, models with initial magnetic energy varying by two orders of magnitude approach the same asymptotic state. In the fully saturated state of the fiducial model, the integrated energy proportions E_kin:E_th:E_mag,t:E_mag,o are 0.35:0.39:0.15:0.11, while the proportions...

  13. Kir2.1 regulates rat smooth muscle cell proliferation, migration, and post-injury carotid neointimal formation.

    Science.gov (United States)

    Qiao, Yong; Tang, Chengchun; Wang, Qingjie; Wang, Dong; Yan, Gaoliang; Zhu, Boqian

    2016-09-01

    Phenotype switching of vascular smooth muscle cells (VSMC) from the contractile type to the synthetic type is a hallmark of vascular disorders such as atherosclerosis and restenosis after angioplasty. Inward rectifier K(+) channel 2.1 (Kir2.1) has been identified in VSMC. However, whether it plays a functional role in regulating cellular transformation remains obscure. In this study, we evaluated the role of Kir2.1 on VSMC proliferation, migration, phenotype switching, and post-injury carotid neointimal formation. Kir2.1 knockdown significantly suppressed platelet-derived growth factor BB-stimulated rat vascular smooth muscle cells (rat-VSMC) proliferation and migration. Deficiency in Kir2.1 contributed to the restoration of smooth muscle α-actin, smooth muscle 22α, and calponin and to a reduction in osteopontin expression in rat-VSMC. Moreover, the in vivo study showed that rat-VSMC switched to proliferative phenotypes and that knockdown of Kir2.1 significantly inhibited neointimal formation after rat carotid injury. Kir2.1 may be a potential therapeutic target in the treatment of cardiovascular diseases, such as atherosclerosis and restenosis following percutaneous coronary intervention. PMID:27387235

  14. Effect of growth regulator Kelpak SL on the formation of aboveground biomass of Festulolium braunii (K. Richt. A. Camus

    Directory of Open Access Journals (Sweden)

    Jacek Sosnowski

    2013-07-01

    Full Text Available A study on the cultivation of Festulolium braunii cv. 'Felopa' was carried out using polyurethane rings with a diameter of 36 cm and a height of 40 cm, which were sunk into the ground to a depth of 30 cm and filled with soil material. In this experiment, Kelpak SL was used as a bioregulator. It consists of natural plant hormones such as auxins (11 mg in dm3 and cytokinins (0.03 mg in dm3. The experimental factors were as follows: A1-control; A2 – 20% solution of the growth regulator; A3 – 40% solution; and A4 – 60% solution. The preparation was applied to all three regrowths in the form of spray, at a rate of 3 cm3 ring-1, at the stem elongation stage. The full period of this experiment was in the years 2010–2011. During this time, detailed investigations were carried out on aboveground biomass yield (g DM ring-1, number of shoots (pcs ring-1, leaf blade length (cm, width of the leaf blade base (mm, leaf greenness index (SPAD. The study showed a significant effect of the growth regulator on the formation of Festulolium braunii biomass. However, its highest effectiveness was observed when the 60% solution was applied.

  15. The bifunctional abiotic stress signalling regulator and endogenous RNA silencing suppressor FIERY1 is required for lateral root formation

    KAUST Repository

    Chen, Hao

    2010-09-28

    The Arabidopsis FIERY1 (FRY1) locus was originally identified as a negative regulator of stress-responsive gene expression and later shown to be required for suppression of RNA silencing. In this study we discovered that the FRY1 locus also regulates lateral root formation. Compared with the wild type, fry1 mutant seedlings generated significantly fewer lateral roots under normal growth conditions and also exhibited a dramatically reduced sensitivity to auxin in inducing lateral root initiation. Using transgenic plants that overexpress a yeast homolog of FRY1 that possesses only the 3\\', 5\\'-bisphosphate nucleotidase activity but not the inositol 1-phosphatase activity, we demonstrated that the lateral root phenotypes in fry1 result from loss of the nucleotidase activity. Furthermore, a T-DNA insertion mutant of another RNA silencing suppressor, XRN4 (but not XRN2 or XRN3), which is an exoribonuclease that is inhibited by the substrate of the FRY1 3\\', 5\\'-bisphosphate nucleotidase, exhibits similar lateral root defects. Although fry1 and xrn4 exhibited reduced sensitivity to ethylene, our experiments demonstrated that restoration of ethylene sensitivity in the fry1 mutant is not sufficient to rescue the lateral root phenotypes of fry1. Our results indicate that RNA silencing modulated by FRY1 and XRN4 plays an important role in shaping root architecture. © 2010 Blackwell Publishing Ltd.

  16. Role of slow relaxation processes in the formation of the Kapitza jump on the boundary between a superconductor and a dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Zelikman, M.A.; Spivak, B.Z.

    1979-02-01

    The effect of slow relaxation of excitons in a superconductor on the thermal Kapitza resistance between a superconductor and a dielectric is considered. It is shown that the presence of a hierarchy of relaxation length in the superconductor leads to the existence near the boundary of a region that is in strong disequilibrium. The observed Kapitza jump depends on the size of the energy gap. The results of the theory agree in order of magnitude with experiment.

  17. Heme oxygenase-1 regulates the major route involved in formation of immune hepatic fibrosis in rats

    Institute of Scientific and Technical Information of China (English)

    DUAN Zhi-jun; YANG Dong; WANG Fei; SUN Ying-jie; SUN Xiao-yu; ZHENG Miao-lei

    2010-01-01

    Background Heme oxygenase (HO) plays roles in some liver diseases, but what it does in immune liver fibrosis is rarely reported. We investigated the regulation mechanisms of HO-1 in rat immune liver fibrosis to find routes for intervention.Methods Male Sprague-Dawley rats were randomly divided into control group (N, n=12), fibrosis group (F, n=20),cobalt protoporphyrin (CoPP) inducing group (Co, n=20) and zinc protoporphyrin (ZnPP) inhibiting group (Zn, n=20). In groups F, Co and Zn, immune liver fibrosis was established with human serum albumin. At the attacked stage, CoPP (5mg/kg) and ZnPP (5 mg/kg) were intraperitoneally injected in groups Co and Zn, respectively. After establishment of rat models, the numbers of rats reduced to 11, 15, 17 and 12 in groups N, F, Co and Zn respectively, because of death during the process. HO-1 in liver was detected by Westem blotting and immunohistochemistry. The indexes of fibrosis were assessed by radioimmunoassay. Concentrations of serum transforming growth factor-β1 (TGF-β1), and tissue inhibitor of metalloproteinses (TIMP-1) were detected using enzyme-linked immunosorbent assay. Hepatic stellate cell (HSC) and proliferation degree of fibrosis were assessed by pathological examination. Data analysis was performed by SPSS 10.0software.Results The expression of HO-1 in group F was significantly higher than that in group N, but lower than that in group Co (P <0.05); while that in group Zn was lower than in group F (P <0.05), but still higher than that in group N (P <0.01).Compared with group N, liver functional and liver fibrosis indicators were increased in group F (P <0.01), while comparing to group F, they were decreased in group Co (P <0.05) and increased in group Zn (P <0.05). CoPP reduced the extent of hepatocellular injury and hepatic fibrosis in comparison with group F (P <0.01), being the opposite effect of ZnPP (P<0.01). HSC was observed using indirect method and the result showed that the number of

  18. Cyclophilin E functions as a negative regulator to influenza virus replication by impairing the formation of the viral ribonucleoprotein complex.

    Directory of Open Access Journals (Sweden)

    Zengfu Wang

    Full Text Available BACKGROUND: The nucleoprotein (NP of influenza A virus is a multifunctional protein that plays a critical role in the replication and transcription of the viral genome. Therefore, examining host factors that interact with NP may shed light on the mechanism of host restriction barriers and the tissue tropism of influenza A virus. Here, Cyclophilin E (CypE, a member of the peptidyl-propyl cis-trans isomerase (PPIase family, was found to bind to NP and inhibit viral replication and transcription. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, CypE was found to interact with NP but not with the other components of the viral ribonucleoprotein complex (VRNP: PB1, PB2, and PA. Mutagenesis data revealed that the CypE domain comprised of residues 137-186 is responsible for its binding to NP. Functional analysis results indicated that CypE is a negative regulator in the influenza virus life cycle. Furthermore, knock-down of CypE resulted in increased levels of three types of viral RNA, suggesting that CypE negatively affects viral replication and transcription. Moreover, up-regulation of CypE inhibited the activity of influenza viral polymerase. We determined that the molecular mechanism by which CypE negatively regulates influenza virus replication and transcription is by interfering with NP self-association and the NP-PB1 and NP-PB2 interactions. CONCLUSIONS/SIGNIFICANCE: CypE is a host restriction factor that inhibits the functions of NP, as well as viral replication and transcription, by impairing the formation of the vRNP. The data presented here will help us to better understand the molecular mechanisms of host restriction barriers, host adaptation, and tissue tropism of influenza A virus.

  19. Regulation of sarcoma cell migration, invasion and invadopodia formation by AFAP1L1 through a phosphotyrosine-dependent pathway.

    Science.gov (United States)

    Tie, S R; McCarthy, D J; Kendrick, T S; Louw, A; Le, C; Satiaputra, J; Kucera, N; Phillips, M; Ingley, E

    2016-04-21

    Invasion and metastasis are controlled by the invadopodia, which delivers matrix-degrading enzymes to the invasion interface permitting cancer cell penetration and spread into healthy tissue. We have identified a novel pathway that directs Lyn/Src family tyrosine kinase signals to the invadopodia to regulate sarcoma cell invasion via the molecule AFAP-1-like-1 (AFAP1L1), a new member of the AFAP (actin filament-associated protein) family. We show that AFAP1L1 can transform cells, promote migration and co-expression with active Lyn profoundly influences cell morphology and movement. AFAP1L1 intersects several invadopodia pathway components through its multiple domains and motifs, including the following (i) pleckstrin homology domains that bind phospholipids generated at the plasma membrane by phosphoinositide 3-kinase, (ii) a direct filamentous-actin binding domain and (iii) phospho-tyrosine motifs (pY136 and pY566) that specifically bind Vav2 and Nck2 SH2 domains, respectively. These phosphotyrosine motifs are essential for AFAP1L1-mediated cytoskeleton regulation. Through its interaction with Vav2, AFAP1L1 regulates Rac activity and downstream control of PAK1/2/3 (p21-activated kinases) phosphorylation of myosin light chain (MLC) kinase and MLC2. AFAP1L1 interaction with Nck2 recruits actin-nucleating complexes. Significantly, in osteosarcoma cell lines, knockdown of AFAP1L1 inhibits phosphorylated MLC2 recruitment to filamentous-actin structures, disrupts invadopodia formation, cell attachment, migration and invasion. These data define a novel pathway that directs Lyn/Src family tyrosine kinase signals to sarcoma cell invadopodia through specific recruitment of Vav2 and Nck2 to phosphorylated AFAP1L1, to control cell migration and invasion. PMID:26212012

  20. The p27 Pathway Modulates the Regulation of Skeletal Growth and Osteoblastic Bone Formation by Parathyroid Hormone-Related Peptide.

    Science.gov (United States)

    Zhu, Min; Zhang, Jing; Dong, Zhan; Zhang, Ying; Wang, Rong; Karaplis, Andrew; Goltzman, David; Miao, Dengshun

    2015-11-01

    Parathyroid hormone-related peptide (PTHrP) 1-84 knock-in mice (Pthrp KI) develop skeletal growth retardation and defective osteoblastic bone formation. To further examine the mechanisms underlying this phenotype, microarray analyses of differential gene expression profiles were performed in long bone extracts from Pthrp KI mice and their wild-type (WT) littermates. We found that the expression levels of p27, p16, and p53 were significantly upregulated in Pthrp KI mice relative to WT littermates. To determine whether p27 was involved in the regulation by PTHrP of skeletal growth and development in vivo, we generated compound mutant mice, which were homozygous for both p27 deletion and the Pthrp KI mutation (p27(-/-) Pthrp KI). We then compared p27(-/-) Pthrp KI mice with p27(-/-), Pthrp KI, and WT littermates. Deletion of p27 in Pthrp KI mice resulted in a longer lifespan, increased body weight, and improvement in skeletal growth. At 2 weeks of age, skeletal parameters, including length of long bones, size of epiphyses, numbers of proliferating cell nuclear antigen (PCNA)-positive chondrocytes, bone mineral density, trabecular bone volume, osteoblast numbers, and alkaline phosphatase (ALP)-, type I collagen-, and osteocalcin-positive bone areas were increased in p27(-/-) mice and reduced in both Pthrp KI and p27(-/-) Pthrp KI mice compared with WT mice; however, these parameters were increased in p27(-/-) Pthrp KI mice compared with Pthrp KI mice. As well, protein expression levels of PTHR, IGF-1, and Bmi-1, and the numbers of total colony-forming unit fibroblastic (CFU-f) and ALP-positive CFU-f were similarly increased in p27(-/-) Pthrp KI mice compared with Pthrp KI mice. Our results demonstrate that deletion of p27 in Pthrp KI mice can partially rescue defects in skeletal growth and osteoblastic bone formation by enhancing endochondral bone formation and osteogenesis. These studies, therefore, indicate that the p27 pathway may function downstream in the action

  1. Promyelocytic Leukemia Protein (PML) Regulates Endothelial Cell Network Formation and Migration in Response to Tumor Necrosis Factor α (TNFα) and Interferon α (IFNα)*

    Science.gov (United States)

    Cheng, Xiwen; Liu, Yu; Chu, Hao; Kao, Hung-Ying

    2012-01-01

    Promyelocytic leukemia protein (PML) is a tumor suppressor that is highly expressed in vascular endothelium and inflamed tissues, yet its role in inflammation-associated cytokine-regulated angiogenesis and underlying mechanism remains largely unclear. We show that tumor necrosis factor α (TNFα) and interferon α (IFNα) stimulate PML expression while suppressing EC network formation and migration, two key events during angiogenesis. By a knockdown approach, we demonstrate that PML is indispensable for TNFα- and IFNα-mediated inhibition of EC network formation. We further demonstrate that signal transducer and activator of transcription 1 (STAT1) binds PML promoter and that is an important regulator of PML expression. Knockdown of STAT1 reduces endogenous PML and blocks TNFα- and IFNα-induced PML accumulation and relieves TNFα- and IFNα-mediated inhibition of EC network formation. Our data also indicate that PML regulates EC migration, in part, by modulating expression of downstream genes, such as negatively regulating integrin β1 (ITGB1). In addition, knockdown of STAT1 or PML alleviates TNFα- and IFNα-mediated inhibition of ITGB1 expression. Antibody blockade demonstrates that ITGB1 is functionally important for PML- and STAT1-regulated EC migration. Taken together, our data provide novel mechanistic insights that PML functions as a negative regulator in EC network formation and migration. PMID:22589541

  2. Emerging boundaries

    DEFF Research Database (Denmark)

    Løvschal, Mette

    2014-01-01

    and formalization. These principles are then used to argue the case for socioconceptual emergence and causality between the lines. This causality appears only in a long-term perspective and implies that, although the development of these boundaries was chronologically displaced across northwestern......This article proposes a processual ontology for the emergence of man-made, linear boundaries across northwestern Europe, particularly in the first millennium BC. Over a significant period of time, these boundaries became new ways of organizing the landscape and settlements—a phenomenon that has...... Europe, elements of this phenomenon emerged along equivalent trajectories. At the same time, variation in the regional incorporation of these linear phenomena points toward situation-specific applications and independent development....

  3. Blurring Boundaries

    DEFF Research Database (Denmark)

    Neergaard, Ulla; Nielsen, Ruth

    2010-01-01

    welfare functions into EU law both from an internal market law and a constitutional law perspective. The main problem areas covered by the Blurring Boundaries project were studied in sub-projects on: 1) Internal market law and welfare services; 2) Fundamental rights and non-discrimination law aspects; and...... 3) Services of general interest. In the Blurring Boundaries project, three aspects of the European Social Model have been particularly highlighted: the constitutionalisation of the European Social Model, its multi-level legal character, and the clash between market access justice at EU level and...

  4. Expression of UME6, a Key Regulator of Candida albicans Hyphal Development, Enhances Biofilm Formation via Hgc1- and Sun41-Dependent Mechanisms

    OpenAIRE

    Banerjee, Mohua; Uppuluri, Priya; Zhao, Xiang R.; Carlisle, Patricia L.; Vipulanandan, Geethanjali; Villar, Cristina C.; López-Ribot, José L.; Kadosh, David

    2013-01-01

    Biofilm formation is associated with the ability of Candida albicans, the major human fungal pathogen, to resist antifungal therapies and grow on tissues, catheters, and medical devices. In order to better understand the relationship between C. albicans morphology and biofilm formation, we examined biofilms generated in response to expression of UME6, a key filament-specific transcriptional regulator. As UME6 levels rise, C. albicans cells are known to transition from yeast to hyphae, and we ...

  5. Identification of a cyclic-di-GMP-modulating response regulator that impacts biofilm formation in a model sulfate reducing bacterium

    Directory of Open Access Journals (Sweden)

    AindrilaMukhopadhyay

    2014-07-01

    Full Text Available We surveyed the eight putative cyclic-di-GMP-modulating response regulators (RRs in Desulfovibrio vulgaris Hildenborough that are predicted to function via two-component signaling. Using purified proteins, we examined cyclic-di-GMP production or turnover in vitro of all eight proteins. The two RRs containing only GGDEF domains (DVU2067, DVU0636 demonstrated cyclic-di-GMP production activity in vitro. Of the remaining proteins, three RRs with HD-GYP domains (DVU0722, DVUA0086 and DVU2933 were confirmed to be Mn2+ dependent phosphodiesterases in vitro and converted cyclic-di-GMP to its linear form, pGpG. DVU0408, containing both cyclic-di-GMP production (GGDEF and degradation domains (EAL, showed cyclic-di-GMP turnover activity in vitro also with production of pGpG. No cyclic-di-GMP related activity could be assigned to the RR DVU0330, containing a metal-dependent phosphohydrolase HD-OD domain, or to the HD-GYP domain RR, DVU1181. Studies included examining the impact of overexpressed cyclic-di-GMP-modulating RRs in the heterologous host E. coli and led to the identification of one RR, DVU0636, with increased cellulose production. Evaluation of a transposon mutant in DVU0636 indicated that the strain was impaired in biofilm formation and demonstrated an altered carbohydrate:protein ratio relative to the D. vulgaris wild type biofilms. However, grown in liquid lactate/sulfate medium, the DVU0636 transposon mutant showed no growth impairment relative to the wild-type strain. Among the eight candidates, only the transposon disruption mutant in the DVU2067 RR presented a growth defect in liquid culture. Our results indicate that, of the two diguanylate cyclases that function as part of two-component signaling, DVU0636 plays an important role in biofilm formation while the function of DVU2067 has pertinence in planktonic growth.

  6. Phosphatidylcholine formation by LPCAT1 is regulated by Ca2+ and the redox status of the cell

    Directory of Open Access Journals (Sweden)

    Soupene Eric

    2012-06-01

    Full Text Available Abstract Background Unsaturated fatty acids are susceptible to oxidation and damaged chains are removed from glycerophospholipids by phospholipase A2. De-acylated lipids are then re-acylated by lysophospholipid acyltransferase enzymes such as LPCAT1 which catalyses the formation of phosphatidylcholine (PC from lysoPC and long-chain acyl-CoA. Results Activity of LPCAT1 is inhibited by Ca2+, and a Ca2+-binding motif of the EF-hand type, EFh-1, was identified in the carboxyl-terminal domain of the protein. The residues Asp-392 and Glu-403 define the loop of the hairpin structure formed by EFh-1. Substitution of D392 and E403 to alanine rendered an enzyme insensitive to Ca2+, which established that Ca2+ binding to that region negatively regulates the activity of the acyltransferase amino-terminal domain. Residue Cys-211 of the conserved motif III is not essential for catalysis and not sufficient for sensitivity to treatment by sulfhydryl-modifier agents. Among the several active cysteine-substitution mutants of LPCAT1 generated, we identified one to be resistant to treatment by sulfhydryl-alkylating and sulfhydryl-oxidizer agents. Conclusion Mutant forms of LPCAT1 that are not inhibited by Ca2+ and sulfhydryl-alkylating and –oxidizing agents will provide a better understanding of the physiological function of a mechanism that places the formation of PC, and the disposal of the bioactive species lysoPC, under the control of the redox status and Ca2+ concentration of the cell.

  7. GABAergic transmission in rat pontine reticular formation regulates the induction phase of anesthesia and modulates hyperalgesia caused by sleep deprivation.

    Science.gov (United States)

    Vanini, Giancarlo; Nemanis, Kriste; Baghdoyan, Helen A; Lydic, Ralph

    2014-07-01

    The oral part of the pontine reticular formation (PnO) contributes to the regulation of sleep, anesthesia and pain. The role of PnO γ-aminobutyric acid (GABA) in modulating these states remains incompletely understood. The present study used time to loss and time to resumption of righting response (LoRR and RoRR) as surrogate measures of loss and resumption of consciousness. This study tested three hypotheses: (i) pharmacologically manipulating GABA levels in rat PnO alters LoRR, RoRR and nociception; (ii) propofol decreases GABA levels in the PnO; and (iii) inhibiting GABA synthesis in the PnO blocks hyperalgesia caused by sleep deprivation. Administering a GABA synthesis inhibitor [3-mercaptopropionic acid (3-MPA)] or a GABA uptake inhibitor [nipecotic acid (NPA)] into rat PnO significantly altered LoRR caused by propofol. 3-MPA significantly decreased LoRR for propofol (-18%). NPA significantly increased LoRR during administration of propofol (36%). Neither 3-MPA nor NPA altered RoRR following cessation of propofol or isoflurane delivery. The finding that LoRR was decreased by 3-MPA and increased by NPA is consistent with measures showing that extracellular GABA levels in the PnO were decreased (41%) by propofol. Thermal nociception was significantly decreased by 3-MPA and increased by NPA, and 3-MPA blocked the hyperalgesia caused by sleep deprivation. The results demonstrate that GABA levels in the PnO regulate the time for loss of consciousness caused by propofol, extend the concept that anesthetic induction and emergence are not inverse processes, and suggest that GABAergic transmission in the PnO mediates hyperalgesia caused by sleep loss. PMID:24674578

  8. CaMKII, but not protein kinase A, regulates Rpt6 phosphorylation and proteasome activity during the formation of long-term memories

    Directory of Open Access Journals (Sweden)

    Timothy J Jarome

    2013-08-01

    Full Text Available CaMKII and Protein Kinase A (PKA are thought to be critical for synaptic plasticity and memory formation through their regulation of protein synthesis. Consistent with this, numerous studies have reported that CaMKII, PKA and protein synthesis are critical for long-term memory formation. Recently, we found that protein degradation through the ubiquitin-proteasome system is also critical for long-term memory formation in the amygdala. However, the mechanism by which ubiquitin-proteasome activity is regulated during memory formation and how protein degradation interacts with known intracellular signaling pathways important for learning remain unknown. Recently, evidence has emerged suggesting that both CaMKII and PKA are capable of regulating proteasome activity in vitro through the phosphorylation of proteasome regulatory subunit Rpt6 at Serine-120, though whether they regulate Rpt6 phosphorylation and proteasome function in vivo remains unknown. In the present study we demonstrate for the first time that fear conditioning transiently modifies a proteasome regulatory subunit and proteasome catalytic activity in the mammalian brain in a CaMKII-dependent manner. We found increases in the phosphorylation of proteasome ATPase subunit Rpt6 at Serine-120 and an enhancement in proteasome activity in the amygdala following fear conditioning. Pharmacological manipulation of CaMKII, but not PKA, in vivo significantly reduced both the learning-induced increase in Rpt6 Serine-120 phosphorylation and the increase in proteasome activity without directly affecting protein polyubiquitination levels. These results indicate a novel role for CaMKII in memory formation through its regulation of protein degradation and suggest that CaMKII regulates Rpt6 phosphorylation and proteasome function both in vitro and in vivo.

  9. Physiological Function of Rac Prophage During Biofilm Formation and Regulation of Rac Excision in Escherichia coli K-12.

    Science.gov (United States)

    Liu, Xiaoxiao; Li, Yangmei; Guo, Yunxue; Zeng, Zhenshun; Li, Baiyuan; Wood, Thomas K; Cai, Xingsheng; Wang, Xiaoxue

    2015-01-01

    Rac or rac-like prophage harbors many genes with important physiological functions, while it remains excision-proficient in several bacterial strains including Escherichia coli, Salmonella spp. and Shigella spp. Here, we found that rac excision is induced during biofilm formation, and the isogenic stain without rac is more motile and forms more biofilms in nutrient-rich medium at early stages in E. coli K-12. Additionally, the presence of rac genes increases cell lysis during biofilm development. In most E. coli strains, rac is integrated into the ttcA gene which encodes a tRNA-thioltransferase. Rac excision in E. coli K-12 leads to a functional change of TtcA, which results in reduced fitness in the presence of carbenicillin. Additionally, we demonstrate that YdaQ (renamed as XisR) is the excisionase of rac in E. coli K-12, and that rac excision is induced by the stationary sigma factor RpoS through inducing xisR expression. Taken together, our results reveal that upon rac integration, not only are new genes introduced into the host, but also there is a functional change in a host enzyme. Hence, rac excision is tightly regulated by host factors to control its stability in the host genome under different stress conditions. PMID:26530864

  10. Enhanced expression of glucose-regulated protein 78 correlates with malondialdehyde levels during the formation of liver cirrhosis in rats

    Science.gov (United States)

    ZHANG, YUN; ZHANG, HUIYING; ZHAO, ZHONGFU; LV, MINLI; JIA, JIANTAO; ZHANG, LILI; TIAN, XIAOXIA; CHEN, YUNXIA; LI, BAOHONG; LIU, MINGSHE; HAN, DEWU; JI, CHENG

    2015-01-01

    The aim of the present study was to explore the role of glucose-regulated protein 78 (GRP78) in the development of liver cirrhosis promoted by intestinal endotoxemia in rats. Fifty-one male Wistar rats were randomly divided into the liver cirrhosis 4-week, 6-week and 8-week groups and the normal control group at each time point. Liver cirrhosis was induced by employing multiple pathogenic factors in the rats. Blood and liver tissues were collected. The levels of alanine aminotransferase (ALT), homocysteine, endotoxin and tumor necrosis factor-α (TNF-α) in the plasma, and TNF-α, malondialdehyde (MDA) and procollagen type III peptide (PIIIP) in the liver tissues were determined. The mRNA and protein expression levels of GRP78 in the liver were detected using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. Morphological changes were observed through hematoxylin and eosin and van Gieson staining of the liver. Liver cirrhosis caused marked histopathological changes to the livers of the rats. Following significant increases in the levels of ALT, homocysteine, endotoxin and TNF-α in the plasma, and TNF-α, MDA and PIIIP in the liver tissues of all experimental groups with the progression of liver cirrhosis, the mRNA and protein expression levels of GRP78 also gradually increased. In addition, correlation analysis indicated that the enhanced expression of GRP78 correlated with the MDA levels of the rats during the formation of liver cirrhosis. PMID:26668603

  11. Definitive Endoderm Formation from Plucked Human Hair-Derived Induced Pluripotent Stem Cells and SK Channel Regulation

    Directory of Open Access Journals (Sweden)

    Anett Illing

    2013-01-01

    Full Text Available Pluripotent stem cells present an extraordinary powerful tool to investigate embryonic development in humans. Essentially, they provide a unique platform for dissecting the distinct mechanisms underlying pluripotency and subsequent lineage commitment. Modest information currently exists about the expression and the role of ion channels during human embryogenesis, organ development, and cell fate determination. Of note, small and intermediate conductance, calcium-activated potassium channels have been reported to modify stem cell behaviour and differentiation. These channels are broadly expressed throughout human tissues and are involved in various cellular processes, such as the after-hyperpolarization in excitable cells, and also in differentiation processes. To this end, human induced pluripotent stem cells (hiPSCs generated from plucked human hair keratinocytes have been exploited in vitro to recapitulate endoderm formation and, concomitantly, used to map the expression of the SK channel (SKCa subtypes over time. Thus, we report the successful generation of definitive endoderm from hiPSCs of ectodermal origin using a highly reproducible and robust differentiation system. Furthermore, we provide the first evidence that SKCas subtypes are dynamically regulated in the transition from a pluripotent stem cell to a more lineage restricted, endodermal progeny.

  12. Albedo Boundary

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-510, 11 October 2003The sharp, nearly straight line that runs diagonally across the center of this April 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image is an albedo boundary. Albedois a term that refers to reflectance of sunlight. A surface with a low albedo is one that appears dark because it reflects less light than a high albedo (bright) surface. On Mars, albedo boundaries occur between two materials of differing texture, particle size, or composition, or some combination of these three factors. The boundary shown here is remarkable because it is so sharp and straight. This is caused by wind. Most likely, the entire surface was once covered with the lower-albedo (darker) material that is now seen in the upper half of the image. At some later time, wind stripped away this darker material from the surfaces in the lower half of the image. The difference in albedo here might be related to composition, and possibly particle size. This picture is located near the southwest rim of Schiaparelli Basin at 5.5oS, 345.9oW. The picture covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the left.

  13. Dissection of Molecular Mechanisms Regulating Protein Body Formation in Maize Endosperm - DE-FG03-95-ER20183

    International Nuclear Information System (INIS)

    Dissection of Molecular Mechanisms Regulating Protein Body Formation in Maize Endosperm - DE-FG03-95-ER20183 Final Technical Report and Patent Summary Dr. Brian A. Larkins, Department of Plant Sciences, University of Arizona, Tucson, AZ 85721 Endosperm texture is an important quality trait in maize, as it influences the shipping characteristics of the grain, its susceptibility to insects, the yield of grits from dry milling, energy costs during wet milling, and the baking and digestibility properties of the flour. There appears to be a causal relationship between kernel hardness and the formation of zein-containing protein bodies, as mutations affecting protein body number and structure are associated with a soft, starchy kernel. In this project we used a variety of approaches to better understand this relationship and investigate the molecular and biochemical changes associated with starchy endosperm mutants. We characterized the distribution of zein mRNAs on endosperm rough endoplasmic reticulum (RER) membranes and the interactions between zein proteins, as each of these could influence the structure of protein bodies. Based on in situ hybridization, mRNAs encoding the 22-kD alpha- and 27-kD gamma-zeins are randomly distributed on RER; hence, mRNA targeting does not appear to influence the formation of protein bodies. Investigation of the interactions between zein proteins (alpha, beta, gamma, delta) with the yeast two-hybrid system showed that interactions between the 19- and 22-alpha-zeins are relatively weak, although each of them interacted strongly with the 10-kD delta-zein. Strong interactions were detected between the alpha- and delta-zeins and the 16-kD gamma- and 15-kD beta-zeins; however, the 50-kD and 27-kD gamma-zeins did not interact detectably with the alpha- and delta-zein proteins. The NH2- and COOH-terminal domains of the 22-kD alpha-zein were found to interact most strongly with the 15-kD beta- and 16-kD gamma-zeins, suggesting the 16-kD and 15

  14. sarA negatively regulates Staphylococcus epidermidis biofilm formation by modulating expression of 1 MDa extracellular matrix binding protein and autolysis‐dependent release of eDNA

    DEFF Research Database (Denmark)

    Christner, Martin; Heinze, Constanze; Busch, Michael;

    2012-01-01

    biofilm formation in mutant 1585ΔsarA. Increased eDNA amounts indirectly resulted from upregulation of metalloprotease SepA, leading to boosted processing of autolysin AtlE, in turn inducing augmented autolysis and release of eDNA. Hence, this study identifies sarA as a negative regulator of Embp‐ and e...

  15. Cross-bedding related anisotropy and its interplay with various boundary conditions in the formation and orientation of joints in an aeolian sandstone

    Science.gov (United States)

    Deng, Shang; Cilona, Antonino; Morrow, Carolyn; Mapeli, Cesar; Liu, Chun; Lockner, David; Prasad, Manika; Aydin, Atilla

    2015-08-01

    Previous research revealed that the cross-bedding related anisotropy in Jurassic aeolian Aztec Sandstone cropping out in the Valley of Fire State Park, Nevada, affects the orientation of compaction bands, also known as anti-cracks or closing mode structures. We hypothesize that cross-bedding should have a similar influence on the orientation of the opening mode joints within the same rock at the same location. To test this hypothesis, we investigated the relationship between the orientation of cross-beds and the orientation of different categories of joint sets including cross-bed package confined joints and joint zones in the Aztec Sandstone. The field data show that the cross-bed package confined joints occur at high-angle to bedding and trend roughly parallel to the dip direction of the cross-beds. In comparison, the roughly N-S trending joint zones appear not to be influenced by the cross-beds in any significant way but frequently truncate against the dune boundaries. To characterize the anisotropy due to cross-bedding in the Aztec Sandstone, we measured the P-wave velocities parallel and perpendicular to bedding from 11 samples and determined an average P-wave anisotropy to be slightly larger than 13%. From these results, a model based on the generalized Hooke's law for anisotropic materials is used to analyze deformation of cross-bedded sandstone as a transversely isotropic material. In the analysis, the dip angle of cross-beds is assumed to be constant and the strike orientation varying from 0° to 359° in the east (x), north (y), and up (z) coordinate system. We find qualitative agreement between most of the model results and the observed field relations between cross-beds and the corresponding joint sets. The results also suggest that uniaxial extension (εzz > εxx = εyy = 0) and axisymmetric extension (εxx = εyy  εzz) would amplify the influence of cross-bedding associated anisotropy on the joint orientation whereas a triaxial extension

  16. Type III methyltransferase M.NgoAX from Neisseria gonorrhoeae FA1090 regulates biofilm formation and human cell invasion

    Directory of Open Access Journals (Sweden)

    Agnieszka eKwiatek

    2015-12-01

    , but more easily penetrate inside the host cells. All these data suggest that the NgoAX methyltransferase, may be implicated in N. gonorrhoeae pathogenicity, involving regulation of biofilm formation, adhesion to host cells and epithelial cell invasion.

  17. Boundary issues

    Science.gov (United States)

    Townsend, Alan R.; Porder, Stephen

    2011-03-01

    What is our point of no return? Caesar proclaimed 'the die is cast' while crossing the Rubicon, but rarely does modern society find so visible a threshold in our continued degradation of ecosystems and the services they provide. Humans have always used their surroundings to make a living— sometimes successfully, sometimes not (Diamond 2005)—and we intuitively know that there are boundaries to our exploitation. But defining these boundaries has been a challenge since Malthus first prophesied that nature would limit the human population (Malthus 1798). In 2009, Rockström and colleagues tried to quantify what the 6.8 billion (and counting) of us could continue to get away with, and what we couldn't (Rockström et al 2009). In selecting ten 'planetary boundaries', the authors contend that a sustainable human enterprise requires treating a number of environmental thresholds as points of no return. They suggest we breach these Rubicons at our own peril, and that we've already crossed three: biodiversity loss, atmospheric CO2, and disruption of the global nitrogen (N) cycle. As they clearly hoped, the very act of setting targets has provoked scientific inquiry about their accuracy, and about the value of hard targets in the first place (Schlesinger 2009). Such debate is a good thing. Despite recent emphasis on the science of human-ecosystem interactions, understanding of our planetary boundaries is still in its infancy, and controversy can speed scientific progress (Engelhardt and Caplan 1987). A few weeks ago in this journal, Carpenter and Bennett (2011) took aim at one of the more controversial boundaries in the Rockström analysis: that for human alteration of the global phosphorus (P) cycle. Rockström's group chose riverine P export as the key indicator, suggesting that humans should not exceed a value that could trigger widespread marine anoxic events—and asserting that we have not yet crossed this threshold. There are defensible reasons for a marine

  18. Single-droplet evaporation kinetics and particle formation in an acoustic levitator. Part 1: evaporation of water microdroplets assessed using boundary-layer and acoustic levitation theories.

    Science.gov (United States)

    Schiffter, Heiko; Lee, Geoffrey

    2007-09-01

    The suitability of a single droplet drying acoustic levitator as a model for the spray drying of aqueous, pharmaceutically-relevant solutes used to produce protein-loaded particles has been examined. The acoustic levitator was initially evaluated by measuring the drying rates of droplets of pure water in dependence of drying-air temperature and flow rate. The measured drying rates were higher than those predicted by boundary layer theory because of the effects of primary acoustic streaming. Sherwood numbers of 2.6, 3.6, and 4.4 at drying-air temperatures of 25 degrees C, 40 degrees C, and 60 degrees C were determined, respectively. Acoustic levitation theory could predict the measured drying rates and Sherwood numbers only when a forced-convection drying-air stream was used to neuralize the retarding effect of secondary acoustic streaming on evaporation rate. At still higher drying-air flow rates, the Ranz-Marshall correlation accurately predicts Sherwood number, provided a stable droplet position in the standing acoustic wave is maintained. The measured Sherwood numbers and droplet Reynolds numbers show that experiments performed in the levitator in still air are taking place effectively under conditions of substantial forced convection. The similitude of these values to those occurring in spray dryers is fortuitous for the suitability of the acoustic levitator as a droplet evaporation model for spray drying. PMID:17582811

  19. The Role of the Regulated Sector in the UK Anti-Money Laundering Framework: Pushing the Boundaries of the Private Police

    Directory of Open Access Journals (Sweden)

    Mo Egan

    2010-06-01

    Full Text Available This article argues that the conceptualisation of private police in current academic literature requires expansion to accommodate the role of the regulated sector in the Anti- Money Laundering (AML framework. Firstly, it evaluates the literature on ‘private police’ and argues that its current parameters are too narrow to accommodate the ‘policing’ role of the regulated sector. Secondly, it lays out the legislative framework that has developed to deal with the problem of money laundering. Thirdly, it contextualises the role of the regulated sector, examining the domestic inter-agency policing relationships within the suspicious activity regime as operationalised in Scotland. Finally, it takes a closer look at how the courts have interpreted the ‘failure to report offence’ under s330 of the Proceeds of Crime Act (POCA 2002 and its consequential effect on the engagement of the regulated sector with the SARs regime.

  20. Sex-Dependent Up-Regulation of Two Splicing Factors, Psf and Srp20, during Hippocampal Memory Formation

    Science.gov (United States)

    Antunes-Martins, Ana; Mizuno, Keiko; Irvine, Elaine E.; Lepicard, Eve M.; Giese, K. Peter

    2007-01-01

    Gene transcription is required for long-term memory (LTM) formation. LTM formation is impaired in a male-specific manner in mice lacking either of the two Ca[superscript 2+] / calmodulin-dependent kinase kinase ("Camkk") genes. Since altered transcription was suggested to cause these impairments in LTM formation, we used microarrays to screen for…

  1. Regulation of Stem Cell Proliferation and Cell Fate Specification by Wingless/Wnt Signaling Gradients Enriched at Adult Intestinal Compartment Boundaries.

    OpenAIRE

    Ai Tian; Hassina Benchabane; Zhenghan Wang; Yashi Ahmed

    2016-01-01

    Intestinal stem cell (ISC) self-renewal and proliferation are directed by Wnt/β-catenin signaling in mammals, whereas aberrant Wnt pathway activation in ISCs triggers the development of human colorectal carcinoma. Herein, we have utilized the Drosophila midgut, a powerful model for ISC regulation, to elucidate the mechanisms by which Wingless (Wg)/Wnt regulates intestinal homeostasis and development. We provide evidence that the Wg signaling pathway, activation of which peaks at each of the m...

  2. Investigations of the role of nonlinear couplings in structure formation and transport regulation: Experiment, simulation, and theory

    International Nuclear Information System (INIS)

    Understanding the physics of shear flow and structure formation in plasmas is a central problem for the advancement of magnetic fusion because of the roles such flows are believed to play in regulating turbulence and transport levels. In this paper, we report on integrated experimental, computational, and theoretical studies of sheared zonal flows and radially extended convective cells, with the aim of assessing the results of theory experiment and theory-simulation comparisons. In particular, simulations are used as test beds for verifying analytical predictions and demonstrating the suitability of techniques such as bispectral analysis for isolating nonlinear couplings in data. Based on intriguing initial results suggesting increased levels of nonlinear coupling occur during L-H transitions, we have undertaken a comprehensive study of bispectral quantities in fluid and gyrokinetic simulations, and compared these results with theoretical expectations. Topics of study include locality and directionality of energy transfer, amplitude scaling, and parameter dependences. Techniques for inferring nonlinear coupling coefficients from data are discussed, and initial results from experimental data are presented. Future experimental studies are motivated. We also present work investigating the role of structures in transport. Analysis of simulation data indicates that the turbulent heat flux can be represented as an ensemble of 'heat pulses' of varying sizes, with a power law distribution. The slope of the power law is shown to determine global transport scaling (i.e. Bohm or gyro-Bohm). Theoretical work studying the dynamics of the largest cells (termed 'streamers') is presented, as well as results from ongoing analysis studying connections between heat pulse distribution and bispectral quantities. (author)

  3. Cyst formation and activation of the extracellular regulated kinase pathway after kidney specific inactivation of Pkd1

    Science.gov (United States)

    Shibazaki, Sekiya; Yu, Zhiheng; Nishio, Saori; Tian, Xin; Thomson, R. Brent; Mitobe, Michihiro; Louvi, Angeliki; Velazquez, Heino; Ishibe, Shuta; Cantley, Lloyd G.; Igarashi, Peter; Somlo, Stefan

    2008-01-01

    Polycystic kidney disease (ADPKD) results from failure of the kidney to properly maintain three-dimensional structure after loss of either polycystin-1 or -2. Mice with kidney selective inactivation of Pkd1 during embryogenesis develop profound renal cystic disease and die from renal failure within 3 weeks of birth. In this model, cysts form exclusively from cells in which Cre recombinase is active, but the apparent pace of cyst expansion varies by segment and cell type. Intercalated cells do not participate in cyst expansion despite the presence of cilia up to at least postnatal day 21. Cystic segments show a persistent increase in proliferation as determined by bromodeoxyuridine (BrdU) incorporation; however, the absolute proliferative index is dependent on the underlying proliferative potential of kidney tubule cells. Components of the extracellular regulated kinase (MAPK/ERK) pathway from Ras through MEK1/2 and ERK1/2 to the effector P90RSK are activated in both perinatal Pkd1 and adult Pkd2 ortholgous gene disease models. The pattern of MAPK/ERK activation is focal and does not correlate with the pattern of active proliferation identified by BrdU uptake. The possibility of a causal relationship between ERK1/2 activation and cyst cell proliferation was assessed in vivo in the acute perinatal Pkd1 model of ADPKD using MEK1/2 inhibitor U0126. U0126 treatment had no effect on progression of cyst formation in this model at doses sufficient to reduce phospho-ERK1/2 in cystic kidneys. Cysts in ADPKD exhibit both increased proliferation and activation of MAPK/ERK, but cyst growth is not prevented by inhibition of ERK1/2 activation. PMID:18263604

  4. Glass formation and unusual hygroscopic growth of iodic acid solution droplets with relevance for iodine oxide particles in the coastal marine boundary layer

    Directory of Open Access Journals (Sweden)

    B. J. Murray

    2012-03-01

    Full Text Available Iodine oxide particles are known to nucleate in the marine boundary layer where gas phase molecular iodine and organoiodine species are produced by macroalgae. There has been some debate over the chemical identity of these particles. Hygroscopic measurements have been used to infer that they are composed of insoluble I2O4, while elemental analysis of laboratory generated particles suggests soluble I2O5 or its hydrated form iodic acid, HIO3 (I2O5 · H2O. In this paper we explore the response of super-micron sized aqueous iodic acid solution droplets to varying humidity using both Raman microscopy and single particle electrodynamic traps. These measurements reveal that the propensity of an iodic acid solution droplet to crystallise is negligible on drying to ~0% relative humidity (RH. On applying mechanical pressure to these droplets they shatter in a manner consistent with an ultra-viscous liquid or a brittle glass, but subsequent water uptake between 10 and 20% RH causes their viscosity to reduce sufficiently that the cracked droplets flow and merge. The persistence of iodic acid solution in an amorphous state, rather than a crystalline state, suggests they will more readily accommodate other condensable material and are therefore more likely to grow to sizes where they may serve as cloud condensation nuclei. On increasing the humidity to ~90% the mass of the droplets only increases by ~20% with a corresponding increase in radius of only ~6 %, which is remarkably small for a highly soluble material. We suggest that the small growth factor of aqueous iodic acid solution droplets is consistent with the small aerosol growth factors observed in field experiments.

  5. IL1RAPL1 Associated with Mental Retardation and Autism Regulates the Formation and Stabilization of Glutamatergic Synapses of Cortical Neurons through RhoA Signaling Pathway

    OpenAIRE

    Hayashi, Takashi; Yoshida, Tomoyuki; Ra, Moonjin; Taguchi, Ryo; Mishina, Masayoshi

    2013-01-01

    Interleukin-1 receptor accessory protein-like 1 (IL1RAPL1) is associated with X-linked mental retardation and autism spectrum disorder. We found that IL1RAPL1 regulates synapse formation of cortical neurons. To investigate how IL1RAPL1 controls synapse formation, we here screened IL1RAPL1-interacting proteins by affinity chromatography and mass spectroscopy. IL1RAPL1 interacted with Mcf2-like (Mcf2l), a Rho guanine nucleotide exchange factor, through the cytoplasmic Toll/IL-1 receptor domain....

  6. Genome-wide mutagenesis of Xanthomonas axonopodis pv. citri reveals novel genetic determinants and regulation mechanisms of biofilm formation.

    Directory of Open Access Journals (Sweden)

    Jinyun Li

    Full Text Available Xanthomonas axonopodis pv. citri (Xac causes citrus canker disease, a major threat to citrus production worldwide. Accumulating evidence suggests that the formation of biofilms on citrus leaves plays an important role in the epiphytic survival of this pathogen prior to the development of canker disease. However, the process of Xac biofilm formation is poorly understood. Here, we report a genome-scale study of Xac biofilm formation in which we identified 92 genes, including 33 novel genes involved in biofilm formation and 7 previously characterized genes, colR, fhaB, fliC, galU, gumD, wxacO, and rbfC, known to be important for Xac biofilm formation. In addition, 52 other genes with defined or putative functions in biofilm formation were identified, even though they had not previously reported been to be associated with biofilm formation. The 92 genes were isolated from 292 biofilm-defective mutants following a screen of a transposon insertion library containing 22,000 Xac strain 306 mutants. Further analyses indicated that 16 of the novel genes are involved in the production of extracellular polysaccharide (EPS and/or lipopolysaccharide (LPS, 7 genes are involved in signaling and regulatory pathways, and 5 genes have unknown roles in biofilm formation. Furthermore, two novel genes, XAC0482, encoding a haloacid dehalogenase-like phosphatase, and XAC0494 (designated as rbfS, encoding a two-component sensor protein, were confirmed to be biofilm-related genes through complementation assays. Our data demonstrate that the formation of mature biofilm requires EPS, LPS, both flagellum-dependent and flagellum-independent cell motility, secreted proteins and extracellular DNA. Additionally, multiple signaling pathways are involved in Xac biofilm formation. This work is the first report on a genome-wide scale of the genetic processes of biofilm formation in plant pathogenic bacteria. The report provides significant new information about the genetic

  7. Up-regulation of Ras/Raf/ERK1/2 signaling in the spinal cord impairs neural cell migration, neurogenesis, synapse formation, and dendritic spine development

    Institute of Scientific and Technical Information of China (English)

    CAO Fu-jiang; ZHANG Xu; LIU Tao; LI Xia-wen; Mazar Malik; FENG Shi-qing

    2013-01-01

    Background The Ras/Raf/ERK1/2 signaling pathway controls many cellular responses such as cell proliferation,migration,differentiation,and death.In the nervous system,emerging evidence also points to a death-promoting role for ERK1/2 in both in vitro and in vivo models of neuronal death.To further investigate how Ras/Raf/ERK1/2 up-regulation may lead to the development of spinal cord injury,we developed a cellular model of Raf/ERK up-regulation by overexpressing c-Raf in cultured spinal cord neurons (SCNs) and dorsal root ganglions (DRGs).Methods DRGs and SCNs were prepared from C57BL/6J mouse pups.DRGs or SCNs were infected with Ad-Raf-1 or Ad-Null adenovirus alone.Cell adhesion assay and cell migration assay were investigated,Dil labeling was employed to examine the effect of the up-regulation of Ras/Raf/ERK1/2 signaling on the dendritic formation of spinal neurons.We used the TO-PRO-3 staining to examine the apoptotic effect of c-Raf on DRGs or SCNs.The effect on the synapse formation of neurons was measured by using immunofluorescence.Results We found that Raf/ERK up-regulation stimulates the migration of both SCNs and DRGs,and impairs the formation of excitatory synapses in SCNs.In addition,we found that Raf/ERK up-regulation inhibits the development of mature dendritic spines in SCNs.Investigating the possible mechanisms through which Raf/ERK up-regulation affects the excitatory synapse formation and dendritic spine development,we discovered that Raf/ERK up-regulation suppresses the development and maturation of SCNs.Conclusion The up-regulation of the Raf/ERK signaling pathway may contribute to the pathogenesis of spinal cord injury through both its impairment of the SCN development and causing neural circuit imbalances.

  8. Divide et impera: boundaries shape the plant body and initiate new meristems.

    Science.gov (United States)

    Wang, Quan; Hasson, Alice; Rossmann, Susanne; Theres, Klaus

    2016-01-01

    485 I. 485 II. 486 III. 491 IV. 491 V. 495 495 References 495 SUMMARY: Boundaries, established and maintained in different regions of the plant body, have diverse functions in development. One role is to separate different cell groups, for example the differentiating cells of a leaf primordium from the pluripotent cells of the apical meristem. Boundary zones are also established during compound leaf development, to separate young leaflets from each other, and in many other positions of the plant body. Recent studies have demonstrated that different boundary zones share similar properties. They are characterized by a low rate of cell divisions and specific patterns of gene expression. In addition, the levels of the plant hormones auxin and brassinosteroids are down-regulated in boundary zones, resulting in a low differentiation level of boundary cells. This feature seems to be crucial for a second important role of boundary zones, the formation of new meristems. The primary shoot meristem, as well as secondary and ectopic shoot meristems, initiate from boundary cells that exhibit competence for meristem formation. PMID:26391543

  9. Live imaging of Drosophila gonad formation reveals roles for Six4 in regulating germline and somatic cell migration

    Directory of Open Access Journals (Sweden)

    Jarman Andrew P

    2007-05-01

    Full Text Available Abstract Background Movement of cells, either as amoeboid individuals or in organised groups, is a key feature of organ formation. Both modes of migration occur during Drosophila embryonic gonad development, which therefore provides a paradigm for understanding the contribution of these processes to organ morphogenesis. Gonads of Drosophila are formed from three distinct cell types: primordial germ cells (PGCs, somatic gonadal precursors (SGPs, and in males, male-specific somatic gonadal precursors (msSGPs. These originate in distinct locations and migrate to associate in two intermingled clusters which then compact to form the spherical primitive gonads. PGC movements are well studied, but much less is known of the migratory events and other interactions undergone by their somatic partners. These appear to move in organised groups like, for example, lateral line cells in zebra fish or Drosophila ovarian border cells. Results We have used time-lapse fluorescence imaging to characterise gonadal cell behaviour in wild type and mutant embryos. We show that the homeodomain transcription factor Six4 is required for the migration of the PGCs and the msSGPs towards the SGPs. We have identified a likely cause of this in the case of PGCs as we have found that Six4 is required for expression of Hmgcr which codes for HMGCoA reductase and is necessary for attraction of PGCs by SGPs. Six4 affects msSGP migration by a different pathway as these move normally in Hmgcr mutant embryos. Additionally, embryos lacking fully functional Six4 show a novel phenotype in which the SGPs, which originate in distinct clusters, fail to coalesce to form unified gonads. Conclusion Our work establishes the Drosophila gonad as a model system for the analysis of coordinated cell migrations and morphogenesis using live imaging and demonstrates that Six4 is a key regulator of somatic cell function during gonadogenesis. Our data suggest that the initial association of SGP clusters

  10. Galaxy Formation with Self-consistently Modeled Stars and Massive Black Holes. I: Feedback-regulated Star Formation and Black Hole Growth

    CERN Document Server

    Kim, Ji-hoon; Abel, Tom

    2011-01-01

    There is mounting evidence for the coevolution of galaxies and their embedded massive black holes (MBHs) in a hierarchical structure formation paradigm. To tackle the nonlinear processes of galaxy-MBH interaction, we describe a self-consistent numerical framework which incorporates both galaxies and MBHs. The high-resolution adaptive mesh refinement (AMR) code Enzo is modified to model the formation and feedback of molecular clouds at their characteristic scale of 15.2 pc and the accretion of gas onto a MBH. Two major channels of MBH feedback, radiative feedback (X-ray photons followed through full 3D adaptive ray tracing) and mechanical feedback (bipolar jets resolved in high-resolution AMR), are employed. We investigate the coevolution of a 9.2e11 Msun galactic halo and its 1e5 Msun embedded MBH at redshift 3 in a cosmological LCDM simulation. The MBH feedback heats the surrounding ISM up to 1e6 K through photoionization and Compton heating and locally suppresses star formation in the galactic inner core. T...

  11. Some observations on boundary conditions for numerical conservation laws

    Science.gov (United States)

    Kamowitz, David

    1988-01-01

    Four choices of outflow boundary conditions are considered for numerical conservation laws. All four methods are stable for linear problems, for which examples are presented where either a boundary layer forms or the numerical scheme, together with the boundary condition, is unstable due to the formation of a reflected shock. A simple heuristic argument is presented for determining the suitability of the boundary condition.

  12. The Nesprin family member ANC-1 regulates synapse formation and axon termination by functioning in a pathway with RPM-1 and β-Catenin.

    Directory of Open Access Journals (Sweden)

    Erik D Tulgren

    2014-07-01

    Full Text Available Mutations in Nesprin-1 and 2 (also called Syne-1 and 2 are associated with numerous diseases including autism, cerebellar ataxia, cancer, and Emery-Dreifuss muscular dystrophy. Nesprin-1 and 2 have conserved orthologs in flies and worms called MSP-300 and abnormal nuclear Anchorage 1 (ANC-1, respectively. The Nesprin protein family mediates nuclear and organelle anchorage and positioning. In the nervous system, the only known function of Nesprin-1 and 2 is in regulation of neurogenesis and neural migration. It remains unclear if Nesprin-1 and 2 regulate other functions in neurons. Using a proteomic approach in C. elegans, we have found that ANC-1 binds to the Regulator of Presynaptic Morphology 1 (RPM-1. RPM-1 is part of a conserved family of signaling molecules called Pam/Highwire/RPM-1 (PHR proteins that are important regulators of neuronal development. We have found that ANC-1, like RPM-1, regulates axon termination and synapse formation. Our genetic analysis indicates that ANC-1 functions via the β-catenin BAR-1, and the ANC-1/BAR-1 pathway functions cell autonomously, downstream of RPM-1 to regulate neuronal development. Further, ANC-1 binding to the nucleus is required for its function in axon termination and synapse formation. We identify variable roles for four different Wnts (LIN-44, EGL-20, CWN-1 and CWN-2 that function through BAR-1 to regulate axon termination. Our study highlights an emerging, broad role for ANC-1 in neuronal development, and unveils a new and unexpected mechanism by which RPM-1 functions.

  13. Direct Determination Of γ′ / γ′+γ / γ Phase Boundaries In Ni-Al-Cr System Based On Enthalpy Of Formation Results Obtained By Calorimetric Solution Method

    Directory of Open Access Journals (Sweden)

    Maciąg T.

    2015-09-01

    Full Text Available The work is a continuation of the research carried out on a high-temperature calorimeter solution type on alloys from Ni-Al-Cr system. Thanks to the construction innovation introduced by authors the device allows the determination of the formation enthalpy of alloys at ambient and elevated temperatures. Experiments described in this article were carried out at three temperatures: 873K, 996K and 1150K on the alloys of the chemical compositions from the Ni75Al25 ÷ Ni87Cr13 section of the Ni-Al-Cr system. On the basis of changes in the enthalpy of formation with increasing chromium content of the alloys, points corresponding to places of phase boundaries γ′ / γ′+γ / γ in Ni-Al-Cr system were determined. A similar relationship was observed in previous studies of alloys from Ni75Al25÷Ni75Cr25 section. For precise determination of these characteristic points a statistical model was applied

  14. The two-component signal transduction system ArlRS regulates Staphylococcus epidermidis biofilm formation in an ica-dependent manner.

    Directory of Open Access Journals (Sweden)

    Yang Wu

    Full Text Available Due to its ability to form biofilms on medical devices, Staphylococcus epidermidis has emerged as a major pathogen of nosocomial infections. In this study, we investigated the role of the two-component signal transduction system ArlRS in regulating S. epidermidis biofilm formation. An ArlRS-deficient mutant, WW06, was constructed using S. epidermidis strain 1457 as a parental strain. Although the growth curve of WW06 was similar to that of SE1457, the mutant strain was unable to form biofilms in vitro. In a rabbit subcutaneous infection model, sterile disks made of polymeric materials were implanted subcutaneously followed with inoculation of WW06 or SE1457. The viable bacteria cells of WW06 recovered from biofilms on the embedded disks were much lower than that of SE1457. Complementation of arlRS genes expression from plasmid in WW06 restored biofilm-forming phenotype both in vivo and in vitro. WW06 maintained the ability to undergo initial attachment. Transcription levels of several genes involved in biofilm formation, including icaADBC, sigB, and sarA, were decreased in WW06, compared to SE1457; and icaR expression was increased in WW06, detected by real-time reverse-transcription PCR. The biofilm-forming phenotype was restored by overexpressing icaADBC in WW06 but not by overexpressing sigB, indicating that ArlRS regulates biofilm formation through the regulation of icaADBC. Gel shift assay showed that ArlR can bind to the promoter region of the ica operon. In conclusion, ArlRS regulates S. epidermidis biofilm formation in an ica-dependent manner, distinct from its role in S. aureus.

  15. Sex-dependent up-regulation of two splicing factors, Psf and Srp20, during hippocampal memory formation

    OpenAIRE

    Antunes-Martins, Ana; Mizuno, Keiko; Irvine, Elaine E.; Eve M. Lepicard; Giese, K. Peter

    2007-01-01

    Gene transcription is required for long-term memory (LTM) formation. LTM formation is impaired in a male-specific manner in mice lacking either of the two Ca2+/calmodulin-dependent kinase kinase (Camkk) genes. Since altered transcription was suggested to cause these impairments in LTM formation, we used microarrays to screen for CaMKKβ-dependent gene expression changes. Here we show that the hippocampal mRNA expression of two splicing factors, splicing factor arginine/serine-rich 3 (Sfrs3/Srp...

  16. Nonneuronal cells regulate synapse formation in the vestibular sensory epithelium via erbB-dependent BDNF expression

    OpenAIRE

    Gómez-Casati, Maria E; MURTIE, JOSHUA C.; Rio, Carlos; Stankovic, Konstantina; Liberman, M. Charles; Corfas, Gabriel

    2010-01-01

    Recent studies indicate that molecules released by glia can induce synapse formation. However, what induces glia to produce such signals, their identity, and their in vivo relevance remain poorly understood. Here we demonstrate that supporting cells of the vestibular organ—cells that have many characteristics of glia—promote synapse formation only when induced by neuron-derived signals. Furthermore, we identify BDNF as the synaptogenic signal produced by these nonneuronal cells. Mice in which...

  17. SIMULATIVE INVESTIGATION OF GRAIN BOUNDARIES IN NiAl ALLOY

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Using embedded atom potentials and molecular static relaxation method or Monte Carlo relaxation method, the grain boundary atomic structures of a series of [100], [110] and [111] symmetric tilt grain boundaries in NiAl with different geometrical indexes and compositions were studied. The grain boundary energies, grain boundary cohesive energies and point defects formation energies at the grain boundary were calculated. The results show that the grain boundaries of NiAl alloy have a periodic unit structure. Grain boundary energies of Al rich grain boundary is very high, but the cohesive energies are lower than those of others. The interaction of point defects and grain boundaries shows that grain boundaries incline to absorb point defects to decrease their orders and to relax the distortions caused by point defects. The boundary atomic structures relaxed by Monte Carlo method show that the disorder of them, grain boundary energies and cohesive energies increase with increasing temperature.

  18. Regulation of the formation of osteoclastic actin rings by proline-rich tyrosine kinase 2 interacting with gelsolin

    OpenAIRE

    Wang, Qiang; Xie, Yi; Du, Quan-Sheng; Wu, Xiao-Jun; FENG, XU; Mei, Lin; McDonald, Jay M.; Xiong, Wen-Cheng

    2003-01-01

    Osteoclast activation is important for bone remodeling and is altered in multiple bone disorders. This process requires cell adhesion and extensive actin cytoskeletal reorganization. Proline-rich tyrosine kinase 2 (PYK2), a major cell adhesion–activated tyrosine kinase in osteoclasts, plays an important role in regulating this event. The mechanisms by which PYK2 regulates actin cytoskeletal organization and osteoclastic activation remain largely unknown. In this paper, we provide evidence tha...

  19. THE FORMATION OF THE STRATEGY OF STATE REGULATION OF THE ESTABLISHMENT AND OPERATION OF INDUSTRIAL AND LOGISTICS SYSTEMS

    OpenAIRE

    Dykan, V.

    2014-01-01

    It is proved that the starting point in the development strategy of state regulation should be scientifically justified and described in detail the concept. It is only on the basis considering factors external and internal environment it is possible to determine the main objective of the strategy and to develop an effective strategy of state regulation. Given the theoretical foundations of industrial and logistics integration of industrial enterprises and their importance in ensuring the comp...

  20. Lamellar eutectic growth with anisotropic interphase boundaries

    OpenAIRE

    Akamatsu, Silvère; Bottin-Rousseau, Sabine; Faivre, G.; Ghosh, S.; Plapp, M.

    2015-01-01

    We present a numerical study of the effect of a free-energy anisotropy of the solid- solid interphase boundaries on the formation of tilted lamellar microstructures during directional solidification of nonfaceted binary eutectic alloys. We used two different methods - phase-field (PF) and dynamic boundary-integral (BI) - to simulate the growth of periodic eutectic patterns in two dimensions. For a given Wulff plot of the interphase boundary, which characterizes a eutectic grain with a given r...

  1. A universal, turbulence-regulated star formation law: from Milky Way clouds to high-redshift disk and starburst galaxies

    CERN Document Server

    Salim, Diane M; Kewley, Lisa J

    2015-01-01

    Whilst the star formation rate (SFR) of molecular clouds and galaxies is key in understanding galaxy evolution, the physical processes which determine the SFR remain unclear. This uncertainty about the underlying physics has resulted in various different star formation laws, all having substantial intrinsic scatter. Extending upon previous works that define the column density of star formation (Sigma_SFR) by the gas column density (Sigma_gas), we develop a new universal star formation (SF) law based on the multi-freefall prescription of gas. This new SF law relies predominantly on the probability density function (PDF) and on the sonic Mach number of the turbulence in the star-forming clouds. By doing so we derive a relation where the star formation rate (SFR) correlates with the molecular gas mass per multi-freefall time, whereas previous models had used the average, single-freefall time. We define a new quantity called maximum (multi-freefall) gas consumption rate (MGCR) and show that the actual SFR is only...

  2. IGF-I Signaling in Osterix-Expressing Cells Regulates Secondary Ossification Center Formation, Growth Plate Maturation, and Metaphyseal Formation During Postnatal Bone Development.

    Science.gov (United States)

    Wang, Yongmei; Menendez, Alicia; Fong, Chak; ElAlieh, Hashem Z; Kubota, Takuo; Long, Roger; Bikle, Daniel D

    2015-12-01

    To investigate the role of IGF-I signaling in osterix (OSX)-expressing cells in the skeleton, we generated IGF-I receptor (IGF-IR) knockout mice ((OSX)IGF-IRKO) (floxed-IGF-IR mice × OSX promoter-driven GFP-labeled cre-recombinase [(OSX)GFPcre]), and monitored postnatal bone development. At day 2 after birth (P2), (OSX)GFP-cre was highly expressed in the osteoblasts in the bone surface of the metaphysis and in the prehypertrophic chondrocytes (PHCs) and inner layer of perichondral cells (IPCs). From P7, (OSX)GFP-cre was highly expressed in PHCs, IPCs, cartilage canals (CCs), and osteoblasts (OBs) in the epiphyseal secondary ossification center (SOC), but was only slightly expressed in the OBs in the metaphysis. Compared with the control mice, the IPC proliferation was decreased in the (OSX)IGF-IRKOs. In these mice, fewer IPCs invaded into the cartilage, resulting in delayed formation of the CC and SOC. Immunohistochemistry indicated a reduction of vessel number and lower expression of VEGF and ephrin B2 in the IPCs and SOC of (OSX)IGF-IRKOs. Quantitative real-time PCR revealed that the mRNA levels of the matrix degradation markers, MMP-9, 13 and 14, were decreased in the (OSX)IGF-IRKOs compared with the controls. The (OSX)IGF-IRKO also showed irregular morphology of the growth plate and less trabecular bone in the tibia and femur from P7 to 7 weeks, accompanied by decreased chondrocyte proliferation, altered chondrocyte differentiation, and decreased osteoblast differentiation. Our data indicate that during postnatal bone development, IGF-I signaling in OSX-expressing IPCs promotes IPC proliferation and cartilage matrix degradation and increases ephrin B2 production to stimulate vascular endothelial growth factor (VEGF) expression and vascularization. These processes are required for normal CC formation in the establishment of the SOC. Moreover, IGF-I signaling in the OSX-expressing PHC is required for growth plate maturation and osteoblast differentiation in

  3. Chromoproteinoids and their ability to form boundary

    International Nuclear Information System (INIS)

    Model systems for boundary structures and cellular systems, particularly when they are a result of natural simulation experiments, are always valuable for the study of the ''Origins of Life''. Lyophilization of chromoproteinoids - peptide like molecules containing prosthetic groups - leads to the formation of boundary structures

  4. Neocarzinostatin-induced Rad51 nuclear focus formation is cell cycle regulated and aberrant in AT cells

    International Nuclear Information System (INIS)

    DNA double-stranded breaks are the most detrimental form of DNA damage and, if not repaired properly, may lead to an accumulation of chromosomal aberrations and eventually tumorigenesis. Proteins of the Rad51/Rad52 epitasis group are crucial for the recombinational repair of DNA double-stranded breaks, whereas the Rad50/NBS1/Mre11 nuclease complex is involved in both the recombinational and the end-joining repair of DNA double-stranded breaks. Herein, we demonstrate that the chemotherapeutic enediyne antibiotic neocarzinostatin induced Rad51, but not NBS1, nuclear focus formation in a cell- cycle-dependent manner. Furthermore, neocarzinostatin-induced Rad51 foci formation revealed a slower kinetic change in AT cells, but not in wild-type or NBS cells. In summary, our results suggest that neocarzinostatin induces Rad51 focus formation through an ATM- and cell-cycle-dependent, but NBS1-independent, pathway

  5. Continental Shelf Boundary - Alaska NAD83

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains Continental Shelf Boundaries (CSB) lines in ESRI shapefile format for the BOEM Alaska Region. The CSB defines the seaward limit of federally...

  6. Atlantic NAD 83 Continental Shelf Boundary (CSB)

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains Continental Shelf Boundary (CSB) lines in ESRI shapefile format for the BOEM Atlantic Region. The CSB defines the seaward limit of federally...

  7. Putative zeatin O-glucosyltransferase OscZOG1 regulates root and shoot development and formation of agronomic traits in rice

    Institute of Scientific and Technical Information of China (English)

    Fang-Qing Guo

    2016-01-01

    As a ubiquitous reaction, glucosylation controls the bioactivity of cytokinins in plant growth and development. Here we show that genetic manipulation of zeatin-O-glucosylation regulates the formation of important agronomic traits in rice by manipulating the expression of OscZOG1 gene, encoding a putative zeatin O-glucosyltransferase. We found that OscZOG1 was preferentially expressed in shoot and root meristematic tissues and nascent organs. The growth of lateral roots was stimulated in the overexpression lines, but inhibited in RNA interference lines. In shoots, knockdown of OscZOG1 expression by RNA interference significantly im-proved tillering, panicle branching, grain number per panicle and seed size, which are important agronomic traits for grain yield. In contrast, constitutive expression of OscZOG1 leads to negative effects on the formation of the grain-yielding traits with a marked increase in the accumulation levels of cis-zeatin O-glucoside (cZOG) in the transgenic rice plants. In this study, our findings demonstrate the feasibility of improving the critical yield-determinant agronomic traits, including tiller number, panicle branches, total grain number per panicle and grain weight by downregulating the expression level of OscZOG1. Our results suggest that modulating the levels of cytokinin glucosylation can function as a fine-tuning switch in regulating the formation of agronomic traits in rice.

  8. Hydra, a model system to trace the emergence of boundaries in developing eumetazoans.

    Science.gov (United States)

    Böttger, Angelika; Hassel, Monika

    2012-01-01

    In developing embryos, boundary formation between neighbouring groups of cells is essential to establish compartments which later fulfil specialized functions. The ability to form such boundaries has likely developed early in animal evolution - due to functional requirements imposed by the necessity to separate tissues which protect the animal, take up food or ensure propagation. Essential for boundary formation are local cues which may be provided by the intersection of diffusible molecules or set locally by activation of membrane-bound receptors and transcription factors. In the simple diploblastic Hydra, a representative of the basally branching metazoan Cnidaria, tissue boundaries are morphologically detectable between the body column and terminally differentiated head and foot structures. In adult polyps, these borders correspond to sharp lines of differential gene expression. They form de novo during regeneration and budding of a young polyp. Functional studies strongly suggest the involvement of FGFR/Notch signalling in the establishment of the parent-bud boundary, and it is very likely that these pathways interact with the WNT and BMP systems. How boundaries in the head and foot regions are generated is still unclear. Expression patterns of transcription factors like Cngsc, HyAlx, HyBra, HyOtx, Prdl-a, CnNK2 and Manacle show strong position dependency and may be involved in regulating gene expression on either side of the boundaries, by interpreting positional information during their formation and maintenance. Due to its simplicity, the easy accessibility to pharmacological interference and, recently, transgenesis, Hydra is an interesting prebilaterian model system to study the emergence of boundary-forming mechanisms during evolution. PMID:22689360

  9. Identification of a chemical inhibitor for nuclear speckle formation: Implications for the function of nuclear speckles in regulation of alternative pre-mRNA splicing

    International Nuclear Information System (INIS)

    Highlights: • We identified tubercidin as a compound inducing aberrant formation of the speckles. • Tubercidin causes delocalization of poly (A)+RNAs from nuclear speckles. • Tubercidin induces dispersion of splicing factors from nuclear speckles. • Tubercidin affects alternative pre-mRNA splicing. • Nuclear speckles play a role in regulation of alternative pre-mRNA splicing. - Abstract: Nuclear speckles are subnuclear structures enriched with RNA processing factors and poly (A)+ RNAs comprising mRNAs and poly (A)+ non-coding RNAs (ncRNAs). Nuclear speckles are thought to be involved in post-transcriptional regulation of gene expression, such as pre-mRNA splicing. By screening 3585 culture extracts of actinomycetes with in situ hybridization using an oligo dT probe, we identified tubercidin, an analogue of adenosine, as an inhibitor of speckle formation, which induces the delocalization of poly (A)+ RNA and dispersion of splicing factor SRSF1/SF2 from nuclear speckles in HeLa cells. Treatment with tubercidin also decreased steady-state MALAT1 long ncRNA, thought to be involved in the retention of SRSF1/SF2 in nuclear speckles. In addition, we found that tubercidin treatment promoted exon skipping in the alternative splicing of Clk1 pre-mRNA. These results suggest that nuclear speckles play a role in modulating the concentration of splicing factors in the nucleoplasm to regulate alternative pre-mRNA splicing

  10. Identification of a chemical inhibitor for nuclear speckle formation: Implications for the function of nuclear speckles in regulation of alternative pre-mRNA splicing

    Energy Technology Data Exchange (ETDEWEB)

    Kurogi, Yutaro; Matsuo, Yota; Mihara, Yuki; Yagi, Hiroaki; Shigaki-Miyamoto, Kaya; Toyota, Syukichi; Azuma, Yuko [Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Chuo-ku, Kumamoto 860-8555 (Japan); Igarashi, Masayuki [Laboratory of Disease Biology, Institute of Microbial Chemistry, Shinagawa-ku, Tokyo 141-0021 (Japan); Tani, Tokio, E-mail: ttani@sci.kumamoto-u.ac.jp [Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Chuo-ku, Kumamoto 860-8555 (Japan)

    2014-03-28

    Highlights: • We identified tubercidin as a compound inducing aberrant formation of the speckles. • Tubercidin causes delocalization of poly (A){sup +}RNAs from nuclear speckles. • Tubercidin induces dispersion of splicing factors from nuclear speckles. • Tubercidin affects alternative pre-mRNA splicing. • Nuclear speckles play a role in regulation of alternative pre-mRNA splicing. - Abstract: Nuclear speckles are subnuclear structures enriched with RNA processing factors and poly (A){sup +} RNAs comprising mRNAs and poly (A){sup +} non-coding RNAs (ncRNAs). Nuclear speckles are thought to be involved in post-transcriptional regulation of gene expression, such as pre-mRNA splicing. By screening 3585 culture extracts of actinomycetes with in situ hybridization using an oligo dT probe, we identified tubercidin, an analogue of adenosine, as an inhibitor of speckle formation, which induces the delocalization of poly (A){sup +} RNA and dispersion of splicing factor SRSF1/SF2 from nuclear speckles in HeLa cells. Treatment with tubercidin also decreased steady-state MALAT1 long ncRNA, thought to be involved in the retention of SRSF1/SF2 in nuclear speckles. In addition, we found that tubercidin treatment promoted exon skipping in the alternative splicing of Clk1 pre-mRNA. These results suggest that nuclear speckles play a role in modulating the concentration of splicing factors in the nucleoplasm to regulate alternative pre-mRNA splicing.

  11. Regulation of Pattern Formation and Gene Amplification During Drosophila Oogenesis by the miR-318 microRNA

    DEFF Research Database (Denmark)

    Ge, Wanzhong; Deng, Qiannan; Guo, Ting; Hong, Xin; Kugler, Jan-Michael; Yang, Xiaohang; Cohen, Stephen M

    2015-01-01

    Pattern formation during epithelial development requires the coordination of multiple signaling pathways. Here, we investigate the functions of an ovary-enriched miRNA, miR-318, in epithelial development during Drosophila oogenesis. miR-318 maternal loss-of-function mutants were female sterile and...

  12. Adenosine contributes to blood flow regulation in the exercising human leg by increasing prostaglandin and nitric oxide formation

    DEFF Research Database (Denmark)

    Mortensen, Stefan; Nyberg, Michael; Thaning, Pia;

    2009-01-01

    Adenosine can induce vasodilation in skeletal muscle, but to what extent adenosine exerts its effect via formation of other vasodilators and whether there is redundancy between adenosine and other vasodilators remain unclear. We tested the hypothesis that adenosine, prostaglandins, and NO act in...

  13. Outer Continental Shelf Submerged Lands Act Boundary - Gulf of Mexico Region NAD27

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains the Submerged Lands Act (SLA) boundary line (also known as State Seaward Boundary (SSB), or Fed State Boundary)in ESRI shapefile formats for...

  14. Outer Continental Shelf Submerged Lands Act Boundary - Alaska Region NAD83

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains the Submerged Lands Act (SLA) boundary (also known as State Seaward Boundary (SSB), or Fed State Boundary) in ESRI shapefile format for the...

  15. Outer Continental Shelf Submerged Lands Act Boundary - Atlantic Region NAD83

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains the Submerged Lands Act (SLA) boundary line (also known as State Seaward Boundary (SSB), or Fed State Boundary) in ESRI shapefile formats for...

  16. Vocational teachers' identity formation through boundary crossing

    OpenAIRE

    Fejes, Andreas; Köpsén, Susanne

    2014-01-01

    Vocational teachers’ prior occupational experiences are construed as those that will guarantee high-quality teaching in vocational education, although individuals are no longer required to have formal teaching qualifications to be employed as teachers in Sweden. This lack of strict requirements raises the issue of the preparedness of vocational teachers to teach their subject matter. Drawing on a socio-cultural understanding of identity, and based on twenty semi-structured interviews with voc...

  17. The regulation of star formation in cool-core clusters: imprints on the stellar populations of brightest cluster galaxies

    Science.gov (United States)

    Loubser, S. I.; Babul, A.; Hoekstra, H.; Mahdavi, A.; Donahue, M.; Bildfell, C.; Voit, G. M.

    2016-02-01

    A fraction of brightest cluster galaxies (BCGs) show bright emission in the ultraviolet and the blue part of the optical spectrum, which has been interpreted as evidence of recent star formation. Most of these results are based on the analysis of broad-band photometric data. Here, we study the optical spectra of a sample of 19 BCGs hosted by X-ray luminous galaxy clusters at 0.15 BCG in Abell 1835 shows remarkable A-type stellar features indicating a relatively large population of young stars, which is extremely unusual even amongst star-forming BCGs. We constrain the mass contribution of these young components to the total stellar mass to be typically between 1 and 3 per cent, but rising to 7 per cent in Abell 1835. We find that the four of the BCGs with strong evidence for recent star formation (and only these four galaxies) are found within a projected distance of 5 kpc of their host cluster's X-ray peak, and the diffuse, X-ray gas surrounding the BCGs exhibits a ratio of the radiative cooling-to-free-fall time (tc/tff) of ≤10. These are also some of the clusters with the lowest central entropy. Our results are consistent with the predictions of the precipitation-driven star formation and active galactic nucleus feedback model, in which the radiatively cooling diffuse gas is subject to local thermal instabilities once the instability parameter tc/tff falls below ˜10, leading to the condensation and precipitation of cold gas. The number of galaxies in our sample where the host cluster satisfies all the criteria for recent and ongoing star formation is small, but their stellar populations suggest a time-scale for star formation to restart of the order of ˜200 Myr.

  18. IL1RAPL1 associated with mental retardation and autism regulates the formation and stabilization of glutamatergic synapses of cortical neurons through RhoA signaling pathway.

    Directory of Open Access Journals (Sweden)

    Takashi Hayashi

    Full Text Available Interleukin-1 receptor accessory protein-like 1 (IL1RAPL1 is associated with X-linked mental retardation and autism spectrum disorder. We found that IL1RAPL1 regulates synapse formation of cortical neurons. To investigate how IL1RAPL1 controls synapse formation, we here screened IL1RAPL1-interacting proteins by affinity chromatography and mass spectroscopy. IL1RAPL1 interacted with Mcf2-like (Mcf2l, a Rho guanine nucleotide exchange factor, through the cytoplasmic Toll/IL-1 receptor domain. Knockdown of endogenous Mcf2l and treatment with an inhibitor of Rho-associated protein kinase (ROCK, the downstream kinase of RhoA, suppressed IL1RAPL1-induced excitatory synapse formation of cortical neurons. Furthermore, we found that the expression of IL1RAPL1 affected the turnover of AMPA receptor subunits. Insertion of GluA1-containing AMPA receptors to the cell surface was decreased, whereas that of AMPA receptors composed of GluA2/3 was enhanced. Mcf2l knockdown and ROCK inhibitor treatment diminished the IL1RAPL1-induced changes of AMPA receptor subunit insertions. Our results suggest that Mcf2l-RhoA-ROCK signaling pathway mediates IL1RAPL1-dependent formation and stabilization of glutamatergic synapses of cortical neurons.

  19. An Amino-Terminal Polo Kinase Interaction Motif Acts in the Regulation of Centrosome Formation and Reveals a Novel Function for centrosomin (cnn) in Drosophila.

    Science.gov (United States)

    Eisman, Robert C; Phelps, Melissa A S; Kaufman, Thomas

    2015-10-01

    The formation of the pericentriolar matrix (PCM) and a fully functional centrosome in syncytial Drosophila melanogaster embryos requires the rapid transport of Cnn during initiation of the centrosome replication cycle. We show a Cnn and Polo kinase interaction is apparently required during embryogenesis and involves the exon 1A-initiating coding exon, suggesting a subset of Cnn splice variants is regulated by Polo kinase. During PCM formation exon 1A Cnn-Long Form proteins likely bind Polo kinase before phosphorylation by Polo for Cnn transport to the centrosome. Loss of either of these interactions in a portion of the total Cnn protein pool is sufficient to remove native Cnn from the pool, thereby altering the normal localization dynamics of Cnn to the PCM. Additionally, Cnn-Short Form proteins are required for polar body formation, a process known to require Polo kinase after the completion of meiosis. Exon 1A Cnn-LF and Cnn-SF proteins, in conjunction with Polo kinase, are required at the completion of meiosis and for the formation of functional centrosomes during early embryogenesis. PMID:26447129

  20. The small GTPase Rab5 homologue Ypt5 regulates cell morphology, sexual development, ion-stress response and vacuolar formation in fission yeast

    International Nuclear Information System (INIS)

    Highlights: •Multiple functions of Rab5 GTPase in fission yeast were found. •Roles of Rab5 in fission yeast were discussed. •Relation between Rab5 and actin cytoskeleton were discussed. -- Abstract: Inner-membrane transport is critical to cell function. Rab family GTPases play an important role in vesicle transport. In mammalian cells, Rab5 is reported to be involved in the regulation of endosome formation, phagocytosis and chromosome alignment. Here, we examined the role of the fission yeast Rab5 homologue Ypt5 using a point mutant allele. Mutant cells displayed abnormal cell morphology, mating, sporulation, endocytosis, vacuole fusion and responses to ion stress. Our data strongly suggest that fission yeast Rab5 is involved in the regulation of various types of cellular functions

  1. The small GTPase Rab5 homologue Ypt5 regulates cell morphology, sexual development, ion-stress response and vacuolar formation in fission yeast

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, Yuta; Katayama, Chisako [Graduate School of Science, Kobe University, 1-1 Rokkodai-cho Nada, Kobe 657-8501 (Japan); Shinohara, Miki; Shinohara, Akira [Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Maekawa, Shohei [Graduate School of Science, Kobe University, 1-1 Rokkodai-cho Nada, Kobe 657-8501 (Japan); Miyamoto, Masaaki, E-mail: miya@kobe-u.ac.jp [Graduate School of Science, Kobe University, 1-1 Rokkodai-cho Nada, Kobe 657-8501 (Japan); Center for Supports to Research and Education Activities, Kobe University, 1-1 Rokkodai-cho Nada, Kobe 657-8501 (Japan)

    2013-11-29

    Highlights: •Multiple functions of Rab5 GTPase in fission yeast were found. •Roles of Rab5 in fission yeast were discussed. •Relation between Rab5 and actin cytoskeleton were discussed. -- Abstract: Inner-membrane transport is critical to cell function. Rab family GTPases play an important role in vesicle transport. In mammalian cells, Rab5 is reported to be involved in the regulation of endosome formation, phagocytosis and chromosome alignment. Here, we examined the role of the fission yeast Rab5 homologue Ypt5 using a point mutant allele. Mutant cells displayed abnormal cell morphology, mating, sporulation, endocytosis, vacuole fusion and responses to ion stress. Our data strongly suggest that fission yeast Rab5 is involved in the regulation of various types of cellular functions.

  2. MicroRNA-17-mediated down-regulation of apoptotic protease activating factor 1 attenuates apoptosome formation and subsequent apoptosis of cardiomyocytes.

    Science.gov (United States)

    Song, Seungjun; Seo, Hyang-Hee; Lee, Se-Yeon; Lee, Chang Yeon; Lee, Jiyun; Yoo, Kyung-Jong; Yoon, Cheesoon; Choi, Eunhyun; Hwang, Ki-Chul; Lee, Seahyoung

    2015-09-18

    Heart diseases such as myocardial infarction (MI) can damage individual cardiomyocytes, leading to the activation of cell death programs. The most scrutinized type of cell death in the heart is apoptosis, and one of the key events during the propagation of apoptotic signaling is the formation of apoptosomes, which relay apoptotic signals by activating caspase-9. As one of the major components of apoptosomes, apoptotic protease activating factor 1 (Apaf-1) facilitates the formation of apoptosomes containing cytochrome c (Cyto-c) and deoxyadenosine triphosphate (dATP). Thus, it may be possible to suppress the activation of the apoptotic program by down-regulating the expression of Apaf-1 using miRNAs. To validate this hypothesis, we selected a number of candidate miRNAs that were expected to target Apaf-1 based on miRNA target prediction databases. Among these candidate miRNAs, we empirically identified miR-17 as a novel Apaf-1-targeting miRNA. The delivery of exogenous miR-17 suppressed Apaf-1 expression and consequently attenuated formation of the apoptosome complex containing caspase-9, as demonstrated by co-immunoprecipitation and immunocytochemistry. Furthermore, miR-17 suppressed the cleavage of procaspase-9 and the subsequent activation of caspase-3, which is downstream of activated caspase-9. Cell viability tests also indicated that miR-17 pretreatment significantly prevented the norepinephrine-induced apoptosis of cardiomyocytes, suggesting that down-regulation of apoptosome formation may be an effective strategy to prevent cellular apoptosis. These results demonstrate the potential of miR-17 as an effective anti-apoptotic agent. PMID:26265044

  3. Temporal and Spatial Regulation of Epsin Abundance and VEGFR3 Signaling are Required for Lymphatic Valve Formation and Function

    OpenAIRE

    Liu, Xiaolei; Pasula, Satish; Song, Hoogeun; Tessneer, Kandice L.; Dong, Yunzhou; Hahn, Scott; Yago, Tadayuki; Brophy, Megan; Chang, Baojun; Cai, Xiaofeng; Wu, Hao; McManus, John; Ichise, Hirotake; Georgescu, Constantin; Wren, Jonathan D

    2014-01-01

    Lymphatic valves prevent the backflow of the lymph fluid and ensure proper lymphatic drainage throughout the body. Local accumulation of lymphatic fluid in tissues, a condition called lymphedema, is common in individuals with malformed lymphatic valves. The vascular endothelial growth factor receptor 3 (VEGFR3) is required for the development of lymphatic vascular system. The abundance of VEGFR3 in collecting lymphatic trunks is high before valve formation and, except at valve regions, decrea...

  4. Myocardial Tbx20 regulates early atrioventricular canal formation and endocardial epithelial-mesenchymal transition via Bmp2

    OpenAIRE

    Cai, Xiaoqiang; Nomura-Kitabayashi, Aya; Cai, Weibin; Yan, Jianyun; Christoffels, Vincent M.; Cai, Chen-Leng

    2011-01-01

    During early embryogenesis, the formation of the cardiac atrioventricular canal (AVC) facilitates the transition of the heart from a linear tube into a chambered organ. However, the genetic pathways underlying this developmental process are poorly understood. The T-box transcription factor Tbx20 is expressed predominantly in the AVC of early heart tube. It was shown that Tbx20 activates Nmyc1 and suppresses Tbx2 expression to promote proliferation and specification of the atrial and ventricul...

  5. Pathways Regulating Spheroid Formation of Human Follicular Thyroid Cancer Cells under Simulated Microgravity Conditions: A Genetic Approach

    OpenAIRE

    Stefan Riwaldt; Johann Bauer; Markus Wehland; Lasse Slumstrup; Sascha Kopp; Elisabeth Warnke; Anita Dittrich; Nils E. Magnusson; Jessica Pietsch; Corydon, Thomas J.; Manfred Infanger; Daniela Grimm

    2016-01-01

    Microgravity induces three-dimensional (3D) growth in numerous cell types. Despite substantial efforts to clarify the underlying mechanisms for spheroid formation, the precise molecular pathways are still not known. The principal aim of this paper is to compare static 1g-control cells with spheroid forming (MCS) and spheroid non-forming (AD) thyroid cancer cells cultured in the same flask under simulated microgravity conditions. We investigated the morphology and gene expression patterns in h...

  6. The Drosophila cell adhesion molecule Klingon is required for long-term memory formation and is regulated by Notch

    OpenAIRE

    Matsuno, Motomi; Horiuchi, Junjiro; Tully, Tim; Saitoe, Minoru

    2008-01-01

    The ruslan (rus) mutant was previously identified in a behavioral screen for mutants defective in long-lasting memory, which consists of two consolidated memory types, anesthesia-resistant memory, and protein synthesis-dependent long-term memory (LTM). We demonstrate here that rus is a new allele of klingon (klg), which encodes a homophilic cell adhesion molecule. Klg is acutely required for LTM but not anesthesia-resistant memory formation, and Klg expression increases upon LTM induction. LT...

  7. The regulation of star formation in cool-core clusters: imprints on the stellar populations of brightest cluster galaxies

    CERN Document Server

    Loubser, S I; Hoekstra, H; Mahdavi, A; Donahue, M; Bildfell, C; Voit, G M

    2015-01-01

    A fraction of brightest cluster galaxies (BCGs) shows bright emission in the UV and the blue part of the optical spectrum, which has been interpreted as evidence of recent star formation. Most of these results are based on the analysis of broadband photometric data. Here, we study the optical spectra of a sample of 19 BCGs hosted by X-ray luminous galaxy clusters at 0.15 < z < 0.3, a subset from the Canadian Cluster Comparison Project (CCCP) sample. We identify plausible star formation histories of the galaxies by fitting Simple Stellar Populations (SSPs) as well as composite populations, consisting of a young stellar component superimposed on an intermediate/old stellar component, to accurately constrain their star formation histories. We detect prominent young (~200 Myr) stellar populations in 4 of the 19 galaxies. Of the four, the BCG in Abell 1835 shows remarkable A-type stellar features indicating a relatively large population of young stars, which is extremely unusual even amongst star forming BCG...

  8. Numerical Simulations of Turbulent, Molecular Clouds Regulated by Radiation Feedback Forces I: Star Formation Rate and Efficiency

    CERN Document Server

    Raskutti, Sudhir; Skinner, M Aaron

    2016-01-01

    Radiation feedback from stellar clusters is expected to play a key role in setting the rate and efficiency of star formation in giant molecular clouds (GMCs). To investigate how radiation forces influence realistic turbulent systems, we have conducted a series of numerical simulations employing the {\\it Hyperion} radiation hydrodynamics solver, considering the regime that is optically thick to ultraviolet (UV) and optically thin to infrared (IR) radiation. Our model clouds cover initial surface densities between $\\Sigma_{\\rm cl,0} \\sim 10-300~M_{\\odot}~{\\rm pc^{-2}}$, with varying initial turbulence. We follow them through turbulent, self-gravitating collapse, formation of star clusters, and cloud dispersal by stellar radiation. All our models display a lognormal distribution of gas surface density $\\Sigma$; for an initial virial parameter $\\alpha_{\\rm vir,0} = 2$, the lognormal standard deviation is $\\sigma_{\\rm ln \\Sigma} = 1-1.5$ and the star formation rate coefficient $\\varepsilon_{\\rm ff,\\bar\\rho} = 0.3-...

  9. Matrix metalloproteinases regulate the formation of dendritic spine head protrusions during chemically induced long-term potentiation.

    Directory of Open Access Journals (Sweden)

    Zsuzsanna Szepesi

    Full Text Available Dendritic spines are are small membranous protrusions that extend from neuronal dendrites and harbor the majority of excitatory synapses. Increasing evidence has shown that matrix metalloproteinases (MMPs, a family of extracellularly acting and Zn(2+-dependent endopeptidases, are able to rapidly modulate dendritic spine morphology. Spine head protrusions (SHPs are filopodia-like processes that extend from the dendritic spine head, representing a form of postsynaptic structural remodeling in response to altered neuronal activity. Herein, we show that chemically induced long-term potentiation (cLTP in dissociated hippocampal cultures upregulates MMP-9 activity that controls the formation of SHPs. Blocking of MMPs activity or microtubule dynamics abolishes the emergence of SHPs. In addition, autoactive recombinant MMP-9, promotes the formation of SHPs in organotypic hippocampal slices. Furthermore, spines with SHPs gained postsynaptic α-amino-3-hydroxyl-5-methyl-4-isoxazole propionic acid (AMPA receptors upon cLTP and the synaptic delivery of AMPA receptors was controlled by MMPs. The present results strongly imply that MMP-9 is functionally involved in the formation of SHPs and the control of postsynaptic receptor distribution upon cLTP.

  10. Rab40b regulates trafficking of MMP2 and MMP9 during invadopodia formation and invasion of breast cancer cells

    OpenAIRE

    Jacob, Abitha; Jing, Jian; Lee, James; Schedin, Pepper; Gilbert, Simon M.; Peden, Andrew A.; Junutula, Jagath R; Prekeris, Rytis

    2013-01-01

    Invadopodia-dependent degradation of the basement membrane plays a major role during metastasis of breast cancer cells. Basement membrane degradation is mediated by targeted secretion of various matrix metalloproteinases (MMPs). Specifically, MMP2 and MMP9 (MMP2/9) possess the ability to hydrolyze components of the basement membrane and regulate various aspects of tumor growth and metastasis. However, the membrane transport machinery that mediates targeting of MMP2/9 to the invadopodia during...

  11. A role for the retinoblastoma protein as a regulator of mouse osteoblast cell adhesion: implications for osteogenesis and osteosarcoma formation.

    Directory of Open Access Journals (Sweden)

    Bernadette Sosa-García

    Full Text Available The retinoblastoma protein (pRb is a cell cycle regulator inactivated in most human cancers. Loss of pRb function results from mutations in the gene coding for pRb or for any of its upstream regulators. Although pRb is predominantly known as a cell cycle repressor, our data point to additional pRb functions in cell adhesion. Our data show that pRb regulates the expression of a wide repertoire of cell adhesion genes and regulates the assembly of the adherens junctions required for cell adhesion. We conducted our studies in osteoblasts, which depend on both pRb and on cell-to-cell contacts for their differentiation and function. We generated knockout mice in which the RB gene was excised specifically in osteoblasts using the cre-lox P system and found that osteoblasts from pRb knockout mice did not assemble adherens junction at their membranes. pRb depletion in wild type osteoblasts using RNAi also disrupted adherens junctions. Microarrays comparing pRb-expressing and pRb-deficient osteoblasts showed that pRb controls the expression of a number of cell adhesion genes, including cadherins. Furthermore, pRb knockout mice showed bone abnormalities consistent with osteoblast adhesion defects. We also found that pRb controls the function of merlin, a well-known regulator of adherens junction assembly, by repressing Rac1 and its effector Pak1. Using qRT-PCR, immunoblots, co-immunoprecipitation assays, and immunofluorescent labeling, we observed that pRb loss resulted in Rac1 and Pak1 overexpression concomitant with merlin inactivation by Pak1, merlin detachment from the membrane, and adherens junction loss. Our data support a pRb function in cell adhesion while elucidating the mechanism for this function. Our work suggests that in some tumor types pRb inactivation results in both a loss of cell cycle control that promotes initial tumor growth as well as in a loss of cell-to-cell contacts, which contributes to later stages of metastasis.

  12. YfbA, a Yersinia pestis Regulator Required for Colonization and Biofilm Formation in the Gut of Cat Fleas

    OpenAIRE

    Tam, Christina; Demke, Owen; Hermanas, Timothy; Mitchell,Anthony; Hendrickx, Antoni P. A.; Schneewind, Olaf

    2014-01-01

    For transmission to new hosts, Yersinia pestis, the causative agent of plague, replicates as biofilm in the foregut of fleas that feed on plague-infected animals or humans. Y. pestis biofilm formation has been studied in the rat flea; however, little is known about the cat flea, a species that may bridge zoonotic and anthroponotic plague cycles. Here, we show that Y. pestis infects and replicates as a biofilm in the foregut of cat fleas in a manner requiring hmsFR, two determinants for extrac...

  13. The mitogen-activated protein kinase gene, VdHog1, regulates osmotic stress response, microsclerotia formation and virulence in Verticillium dahliae.

    Science.gov (United States)

    Wang, Yonglin; Tian, Longyan; Xiong, Dianguang; Klosterman, Steven J; Xiao, Shuxiao; Tian, Chengming

    2016-03-01

    The fungus Verticillium dahliae has gained worldwide notoriety as a destructive plant pathogen, causing vascular wilt diseases on diverse plant species. V. dahliae produces melanized resting bodies, known as microsclerotia, which can survive for 15years in the soil, and are thus critically important in its disease cycle. However, the molecular mechanisms that underpin microsclerotia formation, survival, and germination remain poorly understood. In this study, we observed that deletion of VdHog1 (ΔVdHog1), encoding a homolog of a high-osmolarity glycerol (HOG) response mitogen-activated protein kinase, displayed decreased numbers of melanized microsclerotia in culture, heightened sensitivity to hyperosmotic stress, and increased resistance to the fungicide fludioxonil. Through RNA-Seq analysis, we identified 221 genes differentially expressed in the ΔVdHog1 strain. Interestingly, the expression levels of genes involved in melanin biosynthesis, as well as the hydrophobin gene VDH1, involved in the early stage of microsclerotia formation, were significantly decreased in the ΔVdHog1 strains relative to the wild-type expression levels. The ΔVdHog1 strains exhibited decreased virulence relative to the wild type strain on smoke tree seedlings. These results indicate that VdHog1 regulates hyperosmotic stress responses in V. dahliae, and establishes the Hog1-mediated pathway as a target to further probe the up- and downstream processes that regulate asexual development in this fungus. PMID:26812120

  14. Dietary fish oil and DHA down-regulate antigen-activated CD4+ T-cells while promoting the formation of liquid-ordered mesodomains.

    Science.gov (United States)

    Kim, Wooki; Barhoumi, Rola; McMurray, David N; Chapkin, Robert S

    2014-01-28

    We have demonstrated previously that n-3 PUFA endogenously produced by fat-1 transgenic mice regulate CD4+ T-cell function by affecting the formation of lipid rafts, liquid-ordered mesodomains in the plasma membrane. In the present study, we tested the effects of dietary sources of n-3 PUFA, i.e. fish oil (FO) or purified DHA, when compared with an n-6 PUFA-enriched maize oil control diet in DO11.10 T-cell receptor transgenic mice. Dietary n-3 PUFA were enriched in CD4+ T-cells, resulting in the increase of the n-3:n-6 ratio. Following antigen-specific CD4+ T-cell activation by B-lymphoma cells pulsed with the ovalbumin 323-339 peptide, the formation of liquid-ordered mesodomains at the immunological synapse relative to the whole CD4+ T-cell, as assessed by Laurdan labelling, was increased (P< 0·05) in the FO-fed group. The FO diet also suppressed (P< 0·05) the co-localisation of PKCθ with ganglioside GM1 (monosialotetrahexosylganglioside), a marker for lipid rafts, which is consistent with previous observations. In contrast, the DHA diet down-regulated (P< 0·05) PKCθ signalling by moderately affecting the membrane liquid order at the immunological synapse, suggesting the potential contribution of the other major n-3 PUFA components of FO, including EPA. PMID:23962659

  15. Ubiquitination of HTLV-I Tax in response to DNA damage regulates nuclear complex formation and nuclear export

    Directory of Open Access Journals (Sweden)

    Marriott Susan J

    2007-12-01

    Full Text Available Abstract Background The HTLV-I oncoprotein, Tax, is a pleiotropic protein whose activity is partially regulated by its ability to interact with, and perturb the functions of, numerous cellular proteins. Tax is predominantly a nuclear protein that localizes to nuclear foci known as Tax Speckled Structures (TSS. We recently reported that the localization of Tax and its interactions with cellular proteins are altered in response to various forms of genotoxic and cellular stress. The level of cytoplasmic Tax increases in response to stress and this relocalization depends upon the interaction of Tax with CRM1. Cellular pathways and signals that regulate the subcellular localization of Tax remain to be determined. However, post-translational modifications including sumoylation and ubiquitination are known to influence the subcellular localization of Tax and its interactions with cellular proteins. The sumoylated form of Tax exists predominantly in the nucleus while ubiquitinated Tax exists predominantly in the cytoplasm. Therefore, we hypothesized that post-translational modifications of Tax that occur in response to DNA damage regulate the localization of Tax and its interactions with cellular proteins. Results We found a significant increase in mono-ubiquitination of Tax in response to UV irradiation. Mutation of specific lysine residues (K280 and K284 within Tax inhibited DNA damage-induced ubiquitination. In contrast to wild-type Tax, which undergoes transient nucleocytoplasmic shuttling in response to DNA damage, the K280 and K284 mutants were retained in nuclear foci following UV irradiation and remained co-localized with the cellular TSS protein, sc35. Conclusion This study demonstrates that the localization of Tax, and its interactions with cellular proteins, are dynamic following DNA damage and depend on the post-translational modification status of Tax. Specifically, DNA damage induces the ubiquitination of Tax at K280 and K284

  16. Technology for Boundaries

    DEFF Research Database (Denmark)

    Bødker, Susanne; Kristensen, Jannie Friis; Nielsen, Christina;

    2003-01-01

    .After analysing the history and the current boundary work, the paper will propose new technological support for boundary work. In particular the paper will suggest means of supporting boundaries when these are productive and for changing boundaries when this seems more appropriate. In total, flexible technologies......This paper presents a study of an organisation, which is undergoing a process transforming organisational and technological boundaries. In particular, we shall look at three kinds of boundaries: the work to maintain and change the boundary between the organisation and its customers; boundaries...... between competencies within the organisation; and boundaries between various physical locations of work, in particular between what is done in the office and what is done on site. Maintaining and changing boundaries are the processes through which a particular community sustains its identity and practice...

  17. NOA1 Functions in a Temperature-Dependent Manner to Regulate Chlorophyll Biosynthesis and Rubisco Formation in Rice

    OpenAIRE

    Yang, Qiaosong; He, Han; Li, Heying; Tian, Hua; Zhang, Jianjun; Zhai, Liguang; Chen, Jiandong; Wu, Hong; Yi, Ganjun; He, Zheng-Hui; Peng, Xinxiang

    2011-01-01

    NITRIC OXIDE-ASSOCIATED1 (NOA1) encodes a circularly permuted GTPase (cGTPase) known to be essential for ribosome assembly in plants. While the reduced chlorophyll and Rubisco phenotypes were formerly noticed in both NOA1-supressed rice and Arabidopsis, a detailed insight is still necessary. In this study, by using RNAi transgenic rice, we further demonstrate that NOA1 functions in a temperature-dependent manner to regulate chlorophyll and Rubisco levels. When plants were grown at 30°C, the c...

  18. Transforming Growth Factor β Regulates P-Body Formation through Induction of the mRNA Decay Factor Tristetraprolin

    OpenAIRE

    Blanco, Fernando F.; Sanduja, Sandhya; Deane, Natasha G; Blackshear, Perry J.; Dixon, Dan A.

    2014-01-01

    Transforming growth factor β (TGF-β) is a potent growth regulator and tumor suppressor in normal intestinal epithelium. Likewise, epithelial cell growth is controlled by rapid decay of growth-related mRNAs mediated through 3′ untranslated region (UTR) AU-rich element (ARE) motifs. We demonstrate that treatment of nontransformed intestinal epithelial cells with TGF-β inhibited ARE-mRNA expression. This effect of TGF-β was promoted through increased assembly of cytoplasmic RNA processing (P) bo...

  19. MEG3 long noncoding RNA regulates the TGF-β pathway genes through formation of RNA-DNA triplex structures

    OpenAIRE

    Mondal, Tanmoy; Subhash, Santhilal; Vaid, Roshan; Enroth, Stefan; Uday, Sireesha; Reinius, Björn; Mitra, Sanhita; Mohammed, Arif; James, Alva Rani; Hoberg, Emily; Moustakas, Aristidis; Gyllensten, Ulf; Steven J M Jones; Gustafsson, Claes M.; Sims, Andrew H.

    2015-01-01

    Long noncoding RNAs (lncRNAs) regulate gene expression by association with chromatin, but how they target chromatin remains poorly understood. We have used chromatin RNA immunoprecipitation-coupled high-throughput sequencing to identify 276 lncRNAs enriched in repressive chromatin from breast cancer cells. Using one of the chromatin-interacting lncRNAs, MEG3, we explore the mechanisms by which lncRNAs target chromatin. Here we show that MEG3 and EZH2 share common target genes, including the T...

  20. Enhanced expression of glucose-regulated protein 78 correlates with malondialdehyde levels during the formation of liver cirrhosis in rats

    OpenAIRE

    Zhang, Yun; Zhang, Huiying; Zhao, Zhongfu; Lv, Minli; Jia, Jiantao; Zhang, Lili; Tian, Xiaoxia; Chen, Yunxia; Li, Baohong; LIU, MINGSHE; Han, Dewu; Ji, Cheng

    2015-01-01

    The aim of the present study was to explore the role of glucose-regulated protein 78 (GRP78) in the development of liver cirrhosis promoted by intestinal endotoxemia in rats. Fifty-one male Wistar rats were randomly divided into the liver cirrhosis 4-week, 6-week and 8-week groups and the normal control group at each time point. Liver cirrhosis was induced by employing multiple pathogenic factors in the rats. Blood and liver tissues were collected. The levels of alanine aminotransferase (ALT)...

  1. Rigid supersymmetry with boundaries

    International Nuclear Information System (INIS)

    We construct rigidly supersymmetric bulk-plus-boundary actions, both in x-space and in superspace. For each standard supersymmetric bulk action a minimal supersymmetric bulk-plus-boundary action follows from an extended F- or D-term formula. Additional separately supersymmetric boundary actions can be systematically constructed using co-dimension one multiplets (boundary superfields). We also discuss the orbit of boundary conditions which follow from the Euler-Lagrange variational principle. (orig.)

  2. Regulation of phytohormones on root primordium initiation and adventitious root formation in the etiolated shoots of Paeonia suffruticosa 'Yinfen Jinlin'

    Institute of Scientific and Technical Information of China (English)

    Zeng Duan-xiang; Yin Wei-lun; Zhao Xiao-qing; Wang Hua-fang

    2006-01-01

    Tree peony is well known and sought after for its large, colorful flowers. Its propagation is via vegetative methods. Mechnisms of the adventitious rooting and the regulation of rooting processes are the principles and techniques of plant propagation and improvement. Microstmctures and fluctuations of phytohormones in the adventitious rooting were studied with the etiolated softwood shoots of Paeonia suffruticosa 'Yinfen Jinlin'. There are no pre-primordia in the shoots of the cultivar. Adventitious roots are produced in five stages: shoot selection, primordium initiation, primordium growth, conducting tissue differentiation and root protrusion. Primordia initiated in the cortex. The contents of the endogenous hormones, IAA, ABA and GA, were 5.842, 0.873 and 1.043to GA, CTK and ABA clearly increased at the stage of primordium initiation, while they showed low levels at the stages of primordium growth. The ratios were restored at the shoot levels at the stage of root protrusion. IBA provoked primordia initiation in the cortex, the vascular cambium, the pith and even in the callus induced on the base of shoots. IAA levels in the treated shoots increased gradually to its highest level (three times of control) at the stage of conducting tissue differentiation. The ratios of IAA to GA, CTK and ABA clearly decreased at the stage of primordium initiation. The ratio of IAA to ABA is regulated at 10:1.

  3. Comparative Proteomics of Ovarian Cancer Aggregate Formation Reveals an Increased Expression of Calcium-activated Chloride Channel Regulator 1 (CLCA1).

    Science.gov (United States)

    Musrap, Natasha; Tuccitto, Alessandra; Karagiannis, George S; Saraon, Punit; Batruch, Ihor; Diamandis, Eleftherios P

    2015-07-10

    Ovarian cancer is a lethal gynecological disease that is characterized by peritoneal metastasis and increased resistance to conventional chemotherapies. This increased resistance and the ability to spread is often attributed to the formation of multicellular aggregates or spheroids in the peritoneal cavity, which seed abdominal surfaces and organs. Given that the presence of metastatic implants is a predictor of poor survival, a better understanding of how spheroids form is critical to improving patient outcome, and may result in the identification of novel therapeutic targets. Thus, we attempted to gain insight into the proteomic changes that occur during anchorage-independent cancer cell aggregation. As such, an ovarian cancer cell line, OV-90, was cultured in adherent and non-adherent conditions using stable isotope labeling with amino acids in cell culture (SILAC). Anchorage-dependent cells (OV-90AD) were grown in tissue culture flasks, whereas anchorage-independent cells (OV-90AI) were grown in suspension using the hanging-drop method. Cellular proteins from both conditions were then identified using LC-MS/MS, which resulted in the quantification of 1533 proteins. Of these, 13 and 6 proteins were up-regulated and down-regulated, respectively, in aggregate-forming cells compared with cells grown as monolayers. Relative gene expression and protein expression of candidates were examined in other cell line models of aggregate formation (TOV-112D and ES-2), which revealed an increased expression of calcium-activated chloride channel regulator 1 (CLCA1). Moreover, inhibitor and siRNA transfection studies demonstrated an apparent effect of CLCA1 on cancer cell aggregation. Further elucidation of the role of CLCA1 in the pathogenesis of ovarian cancer is warranted. PMID:26004777

  4. The histone H3K9 methylation and RNAi pathways regulate normalnucleolar and repeated DNA organization by inhibiting formation ofextrachromosomal DNAs

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Jamy C.; Karpen, Gary H.

    2006-06-15

    In order to identify regulators of nuclear organization, Drosophila mutants in the Su(var)3-9 histone H3K9 methyltransferase, RNAi pathway components, and other regulators of heterochromatin-mediated gene silencing were examined for altered nucleoli and positioning of repeated DNAs. Animals lacking components of the H3K9 methylation and RNAi pathways contained disorganized nucleoli, ribosomal DNA (rDNA) and satellite DNAs. The levels of H3K9 dimethylation (H3K9me2) in chromatin associated with repeated DNAs decreased dramatically in Su(var)3-9 and dcr-2 (dicer-2) mutant tissues compared to wild type. We also observed a substantial increase in extrachromosomal repeated DNAs in mutant tissues. The disorganized nucleolus phenotype depends on the presence of Ligase 4 (Lig4), and ecc DNA formation is not induced by removal of cohesin. We conclude that H3K9 methylation of rDNA and satellites, maintained by Su(var)3-9, HP1, and the RNAi pathway, is necessary for the structural stability of repeated DNAs, which is mediated through suppression of non-homologous end joining (NHEJ). These results suggest a mechanism for how local chromatin structure can regulate genome stability, and the organization of chromosomal elements and nuclear organelles.

  5. miR-155 acts as an anti-inflammatory factor in atherosclerosis-associated foam cell formation by repressing calcium-regulated heat stable protein 1.

    Science.gov (United States)

    Li, Xiaoyi; Kong, Deyong; Chen, Heming; Liu, Shuiyi; Hu, Hui; Wu, Tangwei; Wang, Jing; Chen, Weiqun; Ning, Yong; Li, Yong; Lu, Zhongxin

    2016-01-01

    Atherosclerosis (AS) is chronic inflammation in response to lipid accumulation. MicroRNA-155 (miR-155) is being increasingly studied to evaluate its potential as diagnostic biomarkers and therapeutic targets in many diseases. However, delineating the role of miR-155 in AS remains difficult. Here, we detected constitutive expression of several microRNAs (miRNAs) possibly associated with cardiovascular disease in foam cells and clinical specimens from patients with AS. Among them, we found that the level of miR-155 in foam cells was the most significantly elevated in a dose- and time-dependent manner. In addition, the expression of miR-155 was elevated in the plasma and plaque of patients with AS. We also reported for the first time that miR-155 targets calcium-regulated heat stable protein 1 (CARHSP1), which regulates the stability of tumor necrosis factor alpha (TNF-α) mRNA. Furthermore, we investigated the mechanism by which the miR-155 level is elevated. miR-155 upregulation is due to transcriptional regulation by nuclear factor (NF)-κB, which is activated by the inflammatory factor TNF-α. In summary, increased miR-155 relieves chronic inflammation by a negative feedback loop and plays a protective role during atherosclerosis-associated foam cell formation by signaling through the miR-155-CARHSP1-TNF-α pathway. PMID:26899994

  6. Pancreatic amylase is an environmental signal for regulation of biofilm formation and host interaction in Campylobacter jejuni.

    Science.gov (United States)

    Jowiya, Waheed; Brunner, Katja; Abouelhadid, Sherif; Hussain, Haitham A; Nair, Sean P; Sadiq, Sohaib; Williams, Lisa K; Trantham, Emma K; Stephenson, Holly; Wren, Brendan W; Bajaj-Elliott, Mona; Cogan, Tristan A; Laws, Andrew P; Wade, Jim; Dorrell, Nick; Allan, Elaine

    2015-12-01

    Campylobacter jejuni is a commensal bacterium in the intestines of animals and birds and a major cause of food-borne gastroenteritis in humans worldwide. Here we show that exposure to pancreatic amylase leads to secretion of an α-dextran by C. jejuni and that a secreted protease, Cj0511, is required. Exposure of C. jejuni to pancreatic amylase promotes biofilm formation in vitro, increases interaction with human epithelial cell lines, increases virulence in the Galleria mellonella infection model, and promotes colonization of the chicken ileum. We also show that exposure to pancreatic amylase protects C. jejuni from stress conditions in vitro, suggesting that the induced α-dextran may be important during transmission between hosts. This is the first evidence that pancreatic amylase functions as an interkingdom signal in an enteric microorganism. PMID:26438798

  7. Campylobacter jejuni CsrA complements an Escherichia coli csrA mutation for the regulation of biofilm formation, motility and cellular morphology but not glycogen accumulation

    Directory of Open Access Journals (Sweden)

    Fields Joshua A

    2012-10-01

    Full Text Available Abstract Background Although Campylobacter jejuni is consistently ranked as one of the leading causes of bacterial diarrhea worldwide, the mechanisms by which C. jejuni causes disease and how they are regulated have yet to be clearly defined. The global regulator, CsrA, has been well characterized in several bacterial genera and is known to regulate a number of independent pathways via a post transcriptional mechanism, but remains relatively uncharacterized in the genus Campylobacter. Previously, we reported data illustrating the requirement for CsrA in several virulence related phenotypes of C. jejuni strain 81–176, indicating that the Csr pathway is important for Campylobacter pathogenesis. Results We compared the Escherichia coli and C. jejuni orthologs of CsrA and characterized the ability of the C. jejuni CsrA protein to functionally complement an E. coli csrA mutant. Phylogenetic comparison of E. coli CsrA to orthologs from several pathogenic bacteria demonstrated variability in C. jejuni CsrA relative to the known RNA binding domains of E. coli CsrA and in several amino acids reported to be involved in E. coli CsrA-mediated gene regulation. When expressed in an E. coli csrA mutant, C. jejuni CsrA succeeded in recovering defects in motility, biofilm formation, and cellular morphology; however, it failed to return excess glycogen accumulation to wild type levels. Conclusions These findings suggest that C. jejuni CsrA is capable of efficiently binding some E. coli CsrA binding sites, but not others, and provide insight into the biochemistry of C. jejuni CsrA.

  8. The exopolysaccharide gene cluster Bcam1330-Bcam1341 is involved in Burkholderia cenocepacia biofilm formation, and its expression is regulated by c-di-GMP and Bcam1349

    DEFF Research Database (Denmark)

    Fazli, Mustafa; McCarthy, Yvonne; Givskov, Michael; Ryan, Robert P; Tolker-Nielsen, Tim

    2013-01-01

    In Burkholderia cenocepacia, the second messenger cyclic diguanosine monophosphate (c-di-GMP) has previously been shown to positively regulate biofilm formation and the expression of cellulose and type-I fimbriae genes through binding to the transcriptional regulator Bcam1349. Here, we provide...... evidence that cellulose and type-I fimbriae are not involved in B. cenocepacia biofilm formation in flow chambers, and we identify a novel Bcam1349/c-di-GMP-regulated exopolysaccharide gene cluster which is essential for B. cenocepacia biofilm formation. Overproduction of Bcam1349 in trans promotes wrinkly...... matrix exopolysaccharide and to be essential for flow-chamber biofilm formation. We demonstrate that Bcam1349 binds to the promoter region of genes in the Bcam1330-Bcam1341 cluster and that this binding is enhanced by the presence of c-di-GMP. Furthermore, we demonstrate that overproduction of both c-di-GMP...

  9. The Rim101p/PacC pathway and alkaline pH regulate pattern formation in yeast colonies.

    Science.gov (United States)

    Piccirillo, Sarah; White, Melissa G; Murphy, Jeffrey C; Law, Douglas J; Honigberg, Saul M

    2010-03-01

    Multicellular organisms utilize cell-to-cell signals to build patterns of cell types within embryos, but the ability of fungi to form organized communities has been largely unexplored. Here we report that colonies of the yeast Saccharomyces cerevisiae formed sharply divided layers of sporulating and nonsporulating cells. Sporulation initiated in the colony's interior, and this region expanded upward as the colony matured. Two key activators of sporulation, IME1 and IME2, were initially transcribed in overlapping regions of the colony, and this overlap corresponded to the initial sporulation region. The development of colony sporulation patterns depended on cell-to-cell signals, as demonstrated by chimeric colonies, which contain a mixture of two strains. One such signal is alkaline pH, mediated through the Rim101p/PacC pathway. Meiotic-arrest mutants that increased alkali production stimulated expression of an early meiotic gene in neighboring cells, whereas a mutant that decreased alkali production (cit1Delta) decreased this expression. Addition of alkali to colonies accelerated the expansion of the interior region of sporulation, whereas inactivation of the Rim101p pathway inhibited this expansion. Thus, the Rim101 pathway mediates colony patterning by responding to cell-to-cell pH signals. Cell-to-cell signals coupled with nutrient gradients may allow efficient spore formation and spore dispersal in natural environments. PMID:20038633

  10. Study of some properties of point defects in grain boundaries

    International Nuclear Information System (INIS)

    With the aim of deducing simple informations on the grain boundary core structure, we investigated self diffusion under hydrostatic pressure, impurity diffusion (In and Au), electromigration (Sb) along certain types of grain boundaries in Ag bicrystals, and the Moessbauer effect of 57Co located in the grain boundaries of polycrystalline Be. Our results lead to the following conclusions: the formation of a vacancy like defects is necessary to grain boundary diffusion; solute atoms may release most of their elastic energy of dissolution as they segregate at the boundary; in an electrical field, the drift of Sb ions parallel to the boundary takes place toward the anode as in the bulk. The force on the grain boundary ions is larger than in the bulk; Moessbauer spectroscopy revealed the formation of Co-rich aggregates, which may proves important in the study of early stages of grain boundary precipitation. (author)

  11. Manganese-induced regulations in growth, yield formation, quality characters, rice aroma and enzyme involved in 2-acetyl-1-pyrroline biosynthesis in fragrant rice.

    Science.gov (United States)

    Li, Meijuan; Ashraf, Umair; Tian, Hua; Mo, Zhaowen; Pan, Shenggang; Anjum, Shakeel Ahmad; Duan, Meiyang; Tang, Xiangru

    2016-06-01

    Micro-nutrient application is essential for normal plant growth while a little is known about manganese (Mn)-induced regulations in morpho-physiological attributes, aroma formation and enzyme involved in 2-acetyl-1-pyrroline (2-AP) biosynthesis in aromatic rice. Present study aimed to examine the influence of four levels of Mn i.e., Mn1 (100 mg MnSO4 pot(-1)), Mn2 (150 mg MnSO4 pot(-1)), Mn3 (200 mg MnSO4 pot(-1)), and Mn4 (250 mg MnSO4 pot(-1)) on the growth, yield formation, quality characters, rice aroma and enzyme involved in 2-acetyl-1-pyrroline biosynthesis in two fragrant rice cultivars i.e., Meixiangzhan and Nongxiang 18. Pots without Mn application were served as control (Ck). Each pot contained 15 kg of soil. Effects on agronomic characters, quality attributes, 2-AP contents and enzymes involved in 2-AP biosynthesis have been studied in early and late season rice. Results depicted that Mn improved rice growth, yield and related characters, and some quality attributes significantly. It further up-regulated proline, pyrroline-5-carboxylic acid (P5C) (precursors of 2-AP), soluble proteins and activities of proline dehydrogenase (ProDH), Δ(1) pyrroline-5-carboxylic acid synthetase (P5CS) ornithine aminotransferase (OAT) that led to enhanced 2-AP production in rice grains. Moreover, higher Mn levels resulted in increased grain Mn contents in both rice cultivars. Along with growth and yield improvement, Mn application significantly improved rice aromatic contents. Overall, Nongxiang 18 accumulated more 2-AP contents than Meixiangzhan in both seasons under Mn application. This study further explored the importance of Mn in rice aroma formation and signifies that micro-nutrients can play significant roles in rice aroma synthesis; however, intensive studies at molecular levels are still needed to understand the exact mechanisms of Mn to improve rice aroma formation. PMID:26995311

  12. Photoautotrophic Polyhydroxybutyrate Granule Formation Is Regulated by Cyanobacterial Phasin PhaP in Synechocystis sp. Strain PCC 6803.

    Science.gov (United States)

    Hauf, Waldemar; Watzer, Björn; Roos, Nora; Klotz, Alexander; Forchhammer, Karl

    2015-07-01

    Cyanobacteria are photoautotrophic microorganisms which fix atmospheric carbon dioxide via the Calvin-Benson cycle to produce carbon backbones for primary metabolism. Fixed carbon can also be stored as intracellular glycogen, and in some cyanobacterial species like Synechocystis sp. strain PCC 6803, polyhydroxybutyrate (PHB) accumulates when major nutrients like phosphorus or nitrogen are absent. So far only three enzymes which participate in PHB metabolism have been identified in this organism, namely, PhaA, PhaB, and the heterodimeric PHB synthase PhaEC. In this work, we describe the cyanobacterial PHA surface-coating protein (phasin), which we term PhaP, encoded by ssl2501. Translational fusion of Ssl2501 with enhanced green fluorescent protein (eGFP) showed a clear colocalization to PHB granules. A deletion of ssl2501 reduced the number of PHB granules per cell, whereas the mean PHB granule size increased as expected for a typical phasin. Although deletion of ssl2501 had almost no effect on the amount of PHB, the biosynthetic activity of PHB synthase was negatively affected. Secondary-structure prediction and circular dichroism (CD) spectroscopy of PhaP revealed that the protein consists of two α-helices, both of them associating with PHB granules. Purified PhaP forms oligomeric structures in solution, and both α-helices of PhaP contribute to oligomerization. Together, these results support the idea that Ssl2501 encodes a cyanobacterial phasin, PhaP, which regulates the surface-to-volume ratio of PHB granules. PMID:25911471

  13. Kaiso is a key regulator of spleen germinal center formation by repressing Bcl6 expression in splenocytes

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Dong-In; Yoon, Jae-Hyeon; Kim, Min-Kyeong; An, Haemin; Kim, Min-Young; Hur, Man-Wook, E-mail: mwhur2@yuhs.ac

    2013-12-13

    Highlights: •Knockout of Kaiso results in concordant high expression of Bcl6 and c-Myc in spleen. •Kaiso binds the Bcl6 promoter and represses Bcl6 transcription by recruiting NCoR. •Upregulated Bcl6 increases splenocyte proliferation and causes large diffused GC. •Cell cycle-inhibition genes such as Cdkn1b and Cdkn1a are repressed by Bcl6. -- Abstract: Kaiso was previously described as a methylated DNA-binding protein and a transcription repressor interacting with the corepressor protein complex NCoR. In the current study, we show that generation-3 Kaiso knockout mice show a phenotype of splenomegaly and large diffused germinal centers (GC). In the spleens of Kaiso knockout mice, Bcl6 (a transcriptional repressor that plays a critical role in GC development in spleen) and c-Myc were highly expressed, while the cell cycle arrest genes p27 (CDKN1B), p21 (CDKN1A) and Gadd45a were downregulated. Chromatin immunoprecipitation (ChIP) and transcription assays suggested that Kaiso represses Bcl6 expression, and in Kaiso knockout mice, derepressed Bcl6 increased cell proliferation by suppressing p27 (CDKN1B), p21 (CDKN1A) and Gadd45a, while upregulating the oncogene c-Myc. Further evidence for Kaiso regulation of splenomegaly was provided by B lymphocyte Ramos cells, in which ectopic KAISO repressed BCL6 and c-MYC expression, while concomitantly increasing the expression of the cell cycle arrestors p21, p27 and Gadd45a. In summary, derepressed Bcl6 expression may be responsible for increases in GC cell proliferation and splenomegaly of Kaiso knockout mice.

  14. Kaiso is a key regulator of spleen germinal center formation by repressing Bcl6 expression in splenocytes

    International Nuclear Information System (INIS)

    Highlights: •Knockout of Kaiso results in concordant high expression of Bcl6 and c-Myc in spleen. •Kaiso binds the Bcl6 promoter and represses Bcl6 transcription by recruiting NCoR. •Upregulated Bcl6 increases splenocyte proliferation and causes large diffused GC. •Cell cycle-inhibition genes such as Cdkn1b and Cdkn1a are repressed by Bcl6. -- Abstract: Kaiso was previously described as a methylated DNA-binding protein and a transcription repressor interacting with the corepressor protein complex NCoR. In the current study, we show that generation-3 Kaiso knockout mice show a phenotype of splenomegaly and large diffused germinal centers (GC). In the spleens of Kaiso knockout mice, Bcl6 (a transcriptional repressor that plays a critical role in GC development in spleen) and c-Myc were highly expressed, while the cell cycle arrest genes p27 (CDKN1B), p21 (CDKN1A) and Gadd45a were downregulated. Chromatin immunoprecipitation (ChIP) and transcription assays suggested that Kaiso represses Bcl6 expression, and in Kaiso knockout mice, derepressed Bcl6 increased cell proliferation by suppressing p27 (CDKN1B), p21 (CDKN1A) and Gadd45a, while upregulating the oncogene c-Myc. Further evidence for Kaiso regulation of splenomegaly was provided by B lymphocyte Ramos cells, in which ectopic KAISO repressed BCL6 and c-MYC expression, while concomitantly increasing the expression of the cell cycle arrestors p21, p27 and Gadd45a. In summary, derepressed Bcl6 expression may be responsible for increases in GC cell proliferation and splenomegaly of Kaiso knockout mice

  15. Tax Area Boundaries, File name = INDEX Created by MD SDAT in grid format. http://www.harfordcountymd.gov/gis/Index.cfm, Published in 2011, 1:24000 (1in=2000ft) scale, Harford County Government.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Tax Area Boundaries dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2011. It is described as 'File...

  16. County Political Boundaries (National)

    Data.gov (United States)

    Department of Transportation — County boundaries with political limit - boundaries extending into the ocean (NTAD 2015). The TIGER/Line shapefiles and related database files (.dbf) are an extract...

  17. HUD GIS Boundary Files

    Data.gov (United States)

    Department of Housing and Urban Development — The HUD GIS Boundary Files are intended to supplement boundary files available from the U.S. Census Bureau. The files are for community planners interested in...

  18. State Agency Administrative Boundaries

    Data.gov (United States)

    Kansas Data Access and Support Center — This database comprises 28 State agency boundaries and point of contact. The Kansas Geological Survey collected legal descriptions of the boundaries for various...

  19. Evidence for myoblast-extrinsic regulation of slow myosin heavy chain expression during muscle fiber formation in embryonic development.

    Science.gov (United States)

    Cho, M; Webster, S G; Blau, H M

    1993-05-01

    Vertebrate muscles are composed of an array of diverse fast and slow fiber types with different contractile properties. Differences among fibers in fast and slow MyHC expression could be due to extrinsic factors that act on the differentiated myofibers. Alternatively, the mononucleate myoblasts that fuse to form multinucleated muscle fibers could differ intrinsically due to lineage. To distinguish between these possibilities, we determined whether the changes in proportion of slow fibers were attributable to inherent differences in myoblasts. The proportion of fibers expressing slow myosin heavy chain (MyHC) was found to change markedly with time during embryonic and fetal human limb development. During the first trimester, a maximum of 75% of fibers expressed slow MyHC. Thereafter, new fibers formed which did not express this MyHC, so that the proportion of fibers expressing slow MyHC dropped to approximately 3% of the total by midgestation. Several weeks later, a subset of the new fibers began to express slow MyHC and from week 30 of gestation through adulthood, approximately 50% of fibers were slow. However, each myoblast clone (n = 2,119) derived from muscle tissues at six stages of human development (weeks 7, 9, 16, and 22 of gestation, 2 mo after birth and adult) expressed slow MyHC upon differentiation. We conclude from these results that the control of slow MyHC expression in vivo during muscle fiber formation in embryonic development is largely extrinsic to the myoblast. By contrast, human myoblast clones from the same samples differed in their expression of embryonic and neonatal MyHCs, in agreement with studies in other species, and this difference was shown to be stably heritable. Even after 25 population doublings in tissue culture, embryonic stage myoblasts did not give rise to myoblasts capable of expressing MyHCs typical of neonatal stages, indicating that stage-specific differences are not under the control of a division dependent mechanism, or

  20. MrkH, a novel c-di-GMP-dependent transcriptional activator, controls Klebsiella pneumoniae biofilm formation by regulating type 3 fimbriae expression.

    Directory of Open Access Journals (Sweden)

    Jonathan J Wilksch

    2011-08-01

    Full Text Available Klebsiella pneumoniae causes significant morbidity and mortality worldwide, particularly amongst hospitalized individuals. The principle mechanism for pathogenesis in hospital environments involves the formation of biofilms, primarily on implanted medical devices. In this study, we constructed a transposon mutant library in a clinical isolate, K. pneumoniae AJ218, to identify the genes and pathways implicated in biofilm formation. Three mutants severely defective in biofilm formation contained insertions within the mrkABCDF genes encoding the main structural subunit and assembly machinery for type 3 fimbriae. Two other mutants carried insertions within the yfiN and mrkJ genes, which encode GGDEF domain- and EAL domain-containing c-di-GMP turnover enzymes, respectively. The remaining two isolates contained insertions that inactivated the mrkH and mrkI genes, which encode for novel proteins with a c-di-GMP-binding PilZ domain and a LuxR-type transcriptional regulator, respectively. Biochemical and functional assays indicated that the effects of these factors on biofilm formation accompany concomitant changes in type 3 fimbriae expression. We mapped the transcriptional start site of mrkA, demonstrated that MrkH directly activates transcription of the mrkA promoter and showed that MrkH binds strongly to the mrkA regulatory region only in the presence of c-di-GMP. Furthermore, a point mutation in the putative c-di-GMP-binding domain of MrkH completely abolished its function as a transcriptional activator. In vivo analysis of the yfiN and mrkJ genes strongly indicated their c-di-GMP-specific function as diguanylate cyclase and phosphodiesterase, respectively. In addition, in vitro assays showed that purified MrkJ protein has strong c-di-GMP phosphodiesterase activity. These results demonstrate for the first time that c-di-GMP can function as an effector to stimulate the activity of a transcriptional activator, and explain how type 3 fimbriae

  1. Hibiscus sabdariffa leaf polyphenolic extract inhibits LDL oxidation and foam cell formation involving up-regulation of LXRα/ABCA1 pathway.

    Science.gov (United States)

    Chen, Jing-Hsien; Wang, Chau-Jong; Wang, Chi-Ping; Sheu, Jenn-Yuan; Lin, Chia-Liang; Lin, Hui-Hsuan

    2013-11-01

    The oxidative modification of low-density lipoprotein (LDL) is involved in the pathogenesis of atherosclerotic lesions through the formation of macrophage-derived foam cells. In the present study, we aimed to investigate the anti-atherosclerotic effect of Hibiscus sabdariffa leaf polyphenolic extract (HLP), which is rich in flavonoid. The inhibitory effect of HLP on oxidation and lipid peroxidation of LDL was defined in vitro. HLP showed potential in reducing foam cell formation and intracellular lipid accumulation in oxidised-LDL (ox-LDL)-induced macrophage J774A.1 cells under non-cytotoxic concentrations. Molecular data showed these influences of HLP might be mediated via liver-X receptor α (LXRα)/ATP-binding cassette transporter A1 (ABCA1) pathway, as demonstrated by the transfection of LXRα siRNA. Our data implied that HLP up-regulated the LXRα/ABCA1 pathway, which in turn led to stimulation of cholesterol removal from macrophages and delay atherosclerosis. These results suggested that HLP potentially could be developed as an anti-atherosclerotic agent. PMID:23768373

  2. Functional Interactions between 17β-Estradiol and Progesterone Regulate Autophagy during Acini Formation by Bovine Mammary Epithelial Cells in 3D Cultures

    Directory of Open Access Journals (Sweden)

    Katarzyna Zielniok

    2014-01-01

    Full Text Available Mammary gland epithelium forms a network of ducts and alveolar units under control of ovarian hormones: 17-beta-estradiol (E2 and progesterone (P4. Mammary epithelial cells (MECs cultured on reconstituted basement membrane (rBM form three-dimensional (3D acini composed of polarized monolayers surrounding a lumen. Using the 3D culture of BME-UV1 bovine MECs we previously demonstrated that autophagy was induced in the centrally located cells of developing spheroids, and sex steroids increased this process. In the present study we showed that E2 and P4 enhanced the expression of ATG3, ATG5, and BECN1 genes during acini formation, and this effect was accelerated in the presence of both hormones together. The stimulatory action of E2 and P4 was also reflected by increased levels of Atg5, Atg3, and LC3-II proteins. Additionally, the activity of kinases involved in autophagy regulation, Akt, ERK, AMPK, and mTOR, was examined. E2 + P4 slightly increased the level of phosphorylated AMPK but diminished phosphorylated Akt and mTOR on day 9 of 3D culture. Thus, the synergistic actions of E2 and P4 accelerate the development of bovine mammary acini, which may be connected with stimulation of ATGs expression, as well as regulation of signaling pathways (PI3K/Akt/mTOR; AMPK/mTOR involved in autophagy induction.

  3. Watershed Boundaries - Watershed Boundary Database for Montana

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This data set is a complete digital hydrologic unit boundary layer of the Subbasins (8-digit), Watersheds (10-digit), and Subwatersheds (12-digit) for Montana. This...

  4. Cretaceous-tertiary boundary event

    International Nuclear Information System (INIS)

    In badlands along Morgan Creek, southern Saskatchewan, The Cretaceous-Tertiary (K-T) boundary is at the contact of the Frenchman and Ravenscrag Formations. Three sites have been investigated. Evidence of a catastrophic event at the end of the Cretaceous includes data from palynology, geochemistry, and mineralogy; it supports the hypothesis that the K-T boundary event involved the impact of an extraterrestrial object and consequent regional devastation of biotic communities. Palynologic evidence is the abrupt disappearance of many characteristic late Maestrichtian palynomorph (especially angiosperm) taxa and subsequent temporary dominance of assemblages by fern spores. These changes are interpreted, respectively, as (1) destruction of plant communities accompanied by selective extinctions and (2) repopulation of the land surface by opportunistic species prior to development of the typical regional early Paleocene flora. Geochemical analyses (neutron activation and radiochemical separations) revealed iridium abundance anomalies of 3.0, 3.3, and 4.8 ng/g in a 1-3 cm-thick, kaolinitic boundary interval at the three sites. Mineralogic evidence of the probable impact origin of boundary interval components is presence of detrital quartz and feldspar grains as large as 0.40 mm that exhibit shock metamorphic features known only from meteorite impacts or chemical and nuclear explosions

  5. Future Chronological Boundary

    CERN Document Server

    Harris, S G

    1997-01-01

    The purpose of this note is to establish, in a categorical manner, the universality of the Geroch-Kronheimer-Penrose causal boundary when considering the types of causal structures that may profitably be put on any sort of boundary for a spacetime. Actually, this can only be done for the future causal boundary (or the past causal boundary) separately; furthermore, only the chronology relation, not the causality relation, is considered, and the GKP topology is eschewed. The final result is that there is a unique map, with the proper causal properties, from the future causal boundary of a spacetime onto any ``reasonable" boundary which supports some sort of chronological structure and which purports to consist of a future completion of the spacetime. Furthermore, the future causal boundary construction is categorically unique in this regard.

  6. Optimal boundaries for decisions

    Directory of Open Access Journals (Sweden)

    Carfi', David

    2008-01-01

    Full Text Available In this paper we state and prove some new results on the optimal boundaries. These boundaries (called Pareto boundaries too are of increasing importance in the applications to Decision Theory. First of all the Pareto boundaries are the first and most important generalization of the concept of optimum; on the other hand, if f is a real functional defined on a non empty set X and K is a part of X, the determination of the optimal boundaries of the part K with respect to some preorder of X for which f is strictly increasing permits to reduce the optimization problem (f, K, inf (or (f, K, sup to the problem (f, minP(K, inf (resp. (f, maxP(K, sup, where by minP(K we denoted the minimal boundary of K (that in general is greatly smoller than K.

  7. Hamiltonian systems with boundaries

    International Nuclear Information System (INIS)

    Lately, to provide a solid ground for quantization of the open string theory with a constant B-field it has been proposed to treat the boundary conditions as hamiltonian constraints. It seems that this proposal is quite general and it should be applicable to a wide range of models defined on manifolds with boundaries. The goal of the present paper is to show how the boundary conditions can arise as constraints in a purely algebraic fashion within the Hamiltonian approach without any reference to the Lagrangian formulation of the theory. The construction of the boundary Dirac brackets is also given and some subtleties are pointed out. We consider four examples of field theories with boundaries: the topological sigma model, the open string theory with and without a constant B-field and electrodynamics with topological term. A curious result about electrodynamics on a manifold with boundaries is presented. (author)

  8. SLE boundary visits

    CERN Document Server

    Jokela, Niko; Kytölä, Kalle

    2013-01-01

    We study the probabilities with which chordal Schramm-Loewner Evolutions (SLE) visit small neighborhoods of boundary points. We find explicit formulas for general chordal SLE boundary visiting probability amplitudes, also known as SLE boundary zig-zags or order refined SLE multi-point Green's functions on the boundary. Remarkably, an exact answer can be found to this important SLE question for an arbitrarily large number of marked points. The main technique employed is a spin chain - Coulomb gas correspondence between tensor product representations of a quantum group and functions given by Dotsenko-Fateev type integrals. We show how to express these integral formulas in terms of regularized real integrals, and we discuss their numerical evaluation. The results are universal in the sense that apart from an overall multiplicative constant the same formula gives the amplitude for many different formulations of the SLE boundary visit problem. The formula also applies to renormalized boundary visit probabilities f...

  9. Mathematical simulation of point defect interaction with grain boundaries

    International Nuclear Information System (INIS)

    Published works, where the interaction of point defects and grain boundaries was studied by mathematical simulation methods, have been analysed. Energetics of the vacancy formation both in nuclei of large-angle special grain boundaries and in lattice regions adjoining them has been considered. The data obtained permit to explain specific features of grain-boundary diffusion processes. Results of mathematical simulation of the interaction of impurity atoms and boundaries have been considered. Specific features of the helium atom interaction with large-angle grain boundaries are analysed as well

  10. Deformation induced dislocation boundaries: Alignment and effect on mechanical properties

    DEFF Research Database (Denmark)

    Winther, G.; Juul Jensen, D.

    The dislocation boundaries formed during cold-rolling of FCC metals have been reported to have a preferred macroscopic direction with respect to the sample axes. However, boundaries have also been reported to form on crystallographic slip planes. The directions of the boundaries formed on...... crystallographic slip planes are investigated using a newly developed model for formation of such boundaries. It is concluded that these boundaries also lie in the preferred macroscopic direction, i.e. the entire dislocation structure is highly anisotropic. The impact of the anisotropic dislocation structure on...

  11. The homolog of the five SH3-domain protein (HOFI/SH3PXD2B regulates lamellipodia formation and cell spreading.

    Directory of Open Access Journals (Sweden)

    Árpád Lányi

    Full Text Available Motility of normal and transformed cells within and across tissues requires specialized subcellular structures, e.g. membrane ruffles, lamellipodia and podosomes, which are generated by dynamic rearrangements of the actin cytoskeleton. Because the formation of these sub-cellular structures is complex and relatively poorly understood, we evaluated the role of the adapter protein SH3PXD2B [HOFI, fad49, Tks4], which plays a role in the development of the eye, skeleton and adipose tissue. Surprisingly, we find that SH3PXD2B is requisite for the development of EGF-induced membrane ruffles and lamellipodia, as well as for efficient cellular attachment and spreading of HeLa cells. Furthermore, SH3PXD2B is present in a complex with the non-receptor protein tyrosine kinase Src, phosphorylated by Src, which is consistent with SH3PXD2B accumulating in Src-induced podosomes. Furthermore, SH3PXD2B closely follows the subcellular relocalization of cortactin to Src-induced podosomes, EGF-induced membrane ruffles and lamellipodia. Because SH3PXD2B also forms a complex with the C-terminal region of cortactin, we propose that SH3PXD2B is a scaffold protein that plays a key role in regulating the actin cytoskeleton via Src and cortactin.

  12. Effect of Plant Growth Regulators on a Shoot and Root Formation from the Leaf and Flower Culture of a Standard-type Chrysanthemum 'Jinba'

    International Nuclear Information System (INIS)

    In this study we investigated the conditions of a higher frequency for regenerated plants from different explants of a standard-type chrysanthemum 'Jinba'. In vitro culture was initiated on an MS medium containing 3% sucrose, 0.8% agar, and 5 μM benzyl adenine (BA) with naphthalene acetic acid (NAA) by using surface-sterilized leaf and flower tissues from greenhouse-grown plants. Direct shoot regeneration from the leaf and flower explants was obtained 21 to 28 days after the initial culture. Among the seven combinations of the growth regulators used for the culture, the most efficient condition for the shoot and root formation from the leaf tissue was obtained when the MS basic medium was supplemented with 0.5 mg L-¹ BA and 1.0 mg L-¹ NAA, and 0.1 mg L-¹ BA and 0.5 mg L-¹ NAA, while the culture using floret tissues was most efficient on the medium supplemented with 0.5 mg L-¹ BA and 0.5 mg L-¹ NAA, and 0.1 mg L-¹ BA and 1.0 mg L-¹ NAA. These results will provide valuable information to help set up an efficient system for a tissue culture of chrysanthemum cv. Jinba to improve one or some of its negative traits in combination with a radiation mutagenesis approach

  13. Intercellular Adhesion-Dependent Cell Survival and ROCK-Regulated Actomyosin-Driven Forces Mediate Self-Formation of a Retinal Organoid.

    Science.gov (United States)

    Lowe, Albert; Harris, Raven; Bhansali, Punita; Cvekl, Ales; Liu, Wei

    2016-05-10

    In this study we dissected retinal organoid morphogenesis in human embryonic stem cell (hESC)-derived cultures and established a convenient method for isolating large quantities of retinal organoids for modeling human retinal development and disease. Epithelialized cysts were generated via floating culture of clumps of Matrigel/hESCs. Upon spontaneous attachment and spreading of the cysts, patterned retinal monolayers with tight junctions formed. Dispase-mediated detachment of the monolayers and subsequent floating culture led to self-formation of retinal organoids comprising patterned neuroretina, ciliary margin, and retinal pigment epithelium. Intercellular adhesion-dependent cell survival and ROCK-regulated actomyosin-driven forces are required for the self-organization. Our data supports a hypothesis that newly specified neuroretina progenitors form characteristic structures in equilibrium through minimization of cell surface tension. In long-term culture, the retinal organoids autonomously generated stratified retinal tissues, including photoreceptors with ultrastructure of outer segments. Our system requires minimal manual manipulation, has been validated in two lines of human pluripotent stem cells, and provides insight into optic cup invagination in vivo. PMID:27132890

  14. Apoptotic wing degeneration and formation of an altruism-regulating glandular appendage (gemma) in the ponerine ant Diacamma sp. from Japan (Hymenoptera, Formicidae, Ponerinae).

    Science.gov (United States)

    Gotoh, A; Sameshima, S; Tsuji, K; Matsumoto, T; Miura, T

    2005-02-01

    We here show an example of morphological novelties, which have evolved from insect wings into the specific structures controlling social behaviour in an ant species. Most ant colonies consist of winged queen(s) and wingless workers. In the queenless ponerine ant Diacamma sp. from Japan, however, all female workers have a pair of small thoracic appendages, called "gemmae", which are homologous to the forewings and acts as an organ regulating altruism expression. Most workers, whose gemmae are clipped off by other colony members, become nonreproductive helpers, while only a single individual with complete gemmae becomes functionally reproductive. We examined histologically the development of gemmae, and compared it with that of functional wings in males. Female larvae had well-developed wing discs for both fore- and hindwings. At pupation, however, the wing discs started to evaginate and later degenerate. The hindwing discs completely degenerated, while the degeneration of forewing discs was incomplete, leading to the formation of gemmae. The degeneration process involved apoptotic cell death as confirmed by TUNEL assay. In addition, glandular cells differentiated from the epithelial cells of the forewing buds after completion of pupation. The mechanism of developmental transition from wing to gemma can be regarded as an evolutionary gain of new function, which can be seen in insect appendages and vertebrate limbs. PMID:15647944

  15. Dissection of Molecular Mechanisms Regulating Protein Body Formation in Maize Endosperm - DE-FG03-95-ER20183 B139

    Energy Technology Data Exchange (ETDEWEB)

    Brian A. Larkins

    2003-03-21

    Dissection of Molecular Mechanisms Regulating Protein Body Formation in Maize Endosperm - DE-FG03-95-ER20183 Final Technical Report and Patent Summary Dr. Brian A. Larkins, Department of Plant Sciences, University of Arizona, Tucson, AZ 85721 Endosperm texture is an important quality trait in maize, as it influences the shipping characteristics of the grain, its susceptibility to insects, the yield of grits from dry milling, energy costs during wet milling, and the baking and digestibility properties of the flour. There appears to be a causal relationship between kernel hardness and the formation of zein-containing protein bodies, as mutations affecting protein body number and structure are associated with a soft, starchy kernel. In this project we used a variety of approaches to better understand this relationship and investigate the molecular and biochemical changes associated with starchy endosperm mutants. We characterized the distribution of zein mRNAs on endosperm rough endoplasmic reticulum (RER) membranes and the interactions between zein proteins, as each of these could influence the structure of protein bodies. Based on in situ hybridization, mRNAs encoding the 22-kD alpha- and 27-kD gamma-zeins are randomly distributed on RER; hence, mRNA targeting does not appear to influence the formation of protein bodies. Investigation of the interactions between zein proteins (alpha, beta, gamma, delta) with the yeast two-hybrid system showed that interactions between the 19- and 22-alpha-zeins are relatively weak, although each of them interacted strongly with the 10-kD delta-zein. Strong interactions were detected between the alpha- and delta-zeins and the 16-kD gamma- and 15-kD beta-zeins; however, the 50-kD and 27-kD gamma-zeins did not interact detectably with the alpha- and delta-zein proteins. The NH2- and COOH-terminal domains of the 22-kD alpha-zein were found to interact most strongly with the 15-kD beta- and 16-kD gamma-zeins, suggesting the 16-kD and 15

  16. Investigations of the boundary conditions of acicular ferrite formation in fast-quenched welded materials. Final report; Untersuchungen der Randbedingungen fuer die Bildung von 'acicular ferrite' in Schweissguetern bei schneller Abkuehlung. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Dilthey, U.; Biesenbach, M.

    2000-06-19

    The authors investigated the boundary conditions in which a fine-grained ferritic needle structure with sufficient low-temperature toughness is obtained in conditions of extreme heating and cooling. Alloy compositions and welding boundary conditions were investigated for laser welding, electron beam welding in a vacuum and electron beam welding at atmospheric pressure. [German] Im Rahmen dieser Arbeit soll untersucht werden, welche Randbedingungen erfuellt sein muessen, damit sich unter extremen Aufheiz- und Abkuehlbedingungen, wie sie bei den Strahlschweissverfahren vorliegen, ein feinkoerniges nadelferritisches Gefuege mit ausreichend hoher Tieftemperaturzaehigkeit bildet. Diesbezueglich ist fuer die Strahlschweissverfahren Laserstrahlschweissen, Elektronenstrahlschweissen im Vakuum und Elektronenstrahlschweissen unter Atmosphaerendruck zu ermitteln, welche Legierungszusammensetzungen diese Voraussetzungen erfuellen und wie sie unter realen Schweissbedingungen verwirklicht werden koennen. (orig.)

  17. Turbulence and intermittent transport at the boundary of magnetized plasmas

    DEFF Research Database (Denmark)

    Garcia, O.E.; Naulin, V.; Nielsen, A.H.;

    2005-01-01

    Numerical fluid simulations of interchange turbulence for geometry and parameters relevant to the boundary region of magnetically confined plasmas are shown to result in intermittent transport qualitatively similar to recent experimental measurements. The two-dimensional simulation domain features...... a forcing region with spatially localized sources of particles and heat outside which losses due to the motion along open magnetic-field lines dominate, corresponding to the edge region and the scrape-off layer, respectively. Turbulent states reveal intermittent eruptions of hot plasma from the edge...... formation of blob structures is thus related to profile variations, which are here triggered in a quasiperiodic manner by a global dynamical regulation due to the self-sustained sheared flows. (C) 2005 American Institute of Physics....

  18. Boundary definition of a multiverse measure

    CERN Document Server

    Bousso, Raphael; Leichenauer, Stefan; Rosenhaus, Vladimir

    2010-01-01

    We propose to regulate the infinities of eternal inflation by relating a late time cut-off in the bulk to a short distance cut-off on the future boundary. The light-cone time of an event is defined in terms of the volume of its future light-cone on the boundary. We seek an intrinsic definition of boundary volumes that makes no reference to bulk structures. This requires taming the fractal geometry of the future boundary, and lifting the ambiguity of the conformal factor. We propose to work in the conformal frame in which the boundary Ricci scalar is constant. We explore this proposal in the FRW approximation for bubble universes. Remarkably, we find that the future boundary becomes a round three-sphere, with smooth metric on all scales. Our cut-off yields the same relative probabilities as a previous proposal that defined boundary volumes by projection into the bulk along timelike geodesics. Moreover, it is equivalent to an ensemble of causal patches defined without reference to bulk geodesics. It thus yields...

  19. Strand-specific contacts and divalent metal ion regulate double-strand break formation by the GIY-YIG homing endonuclease I-BmoI.

    Science.gov (United States)

    Carter, Jonathan M; Friedrich, Nancy C; Kleinstiver, Benjamin; Edgell, David R

    2007-11-23

    GIY-YIG homing endonucleases are modular enzymes consisting of a well-defined N-terminal catalytic domain connected to a variable C-terminal DNA-binding domain. Previous studies have revealed that the role of the DNA-binding domain is to recognize and bind intronless DNA substrate, positioning the N-terminal catalytic domain such that it is poised to generate a staggered double-strand break by an unknown mechanism. Interactions of the N-terminal catalytic domain with intronless substrate are therefore a critical step in the reaction pathway but have been difficult to define. Here, we have taken advantage of the reduced activity of I-BmoI, an isoschizomer of the well-studied bacteriophage T4 homing endonuclease I-TevI, to examine double-strand break formation by I-BmoI. We present evidence demonstrating that I-BmoI generates a double-strand break by two sequential but chemically independent nicking reactions where divalent metal ion is a limiting factor in top-strand nicking. We also show by in-gel footprinting that contacts by the I-BmoI catalytic domain induce significant minor groove DNA distortions that occur independently of bottom-strand nicking. Bottom-strand contacts are critical for accurate top-strand nicking, whereas top-strand contacts have little influence on the accuracy of bottom-strand nicking. We discuss our results in the context of current models of GIY-YIG endonuclease function, with emphasis on the role of divalent metal ion and strand-specific contacts in regulating the activity of a single active site to generate a staggered double-strand break. PMID:17936302

  20. An integrated molecular landscape implicates the regulation of dendritic spine formation through insulin-related signalling in obsessive–compulsive disorder

    Science.gov (United States)

    van de Vondervoort, Ilse; Poelmans, Geert; Aschrafi, Armaz; Pauls, David L.; Buitelaar, Jan K.; Glennon, Jeffrey C.; Franke, Barbara

    2016-01-01

    Background Obsessive–compulsive disorder (OCD) is a neuropsychiatric disorder with onset in childhood and is characterized by obsessions (recurrent, intrusive, persistent thoughts, impulses and/or ideas that often cause anxiety or distress) and compulsions (ritualized and stereotypic behaviours or mental acts that are often performed to relieve anxiety or distress associated with obsessions). Although OCD is a heritable disorder, its complex molecular etiology is poorly understood. Methods We combined enrichment analyses and an elaborate literature review of the top-ranked genes emerging from the 2 published genome-wide association studies of OCD and candidate genes implicated through other evidence in order to identify biological processes that, when dysregulated, increase the risk for OCD. Results The resulting molecular protein landscape was enriched for proteins involved in regulating postsynaptic dendritic spine formation — and hence synaptic plasticity — through insulin-dependent molecular signalling cascades. Limitations This study is a first attempt to integrate molecuar information from different sources in order to identify biological mechanisms underlying OCD etiology. Our findings are constrained by the limited information from hypothesis-free studies and the incompleteness and existing limitations of the OCD literature and the gene function annotations of gene enrichment tools. As this study was solely based on in silico analyses, experimental validation of the provided hypotheses is warranted. Conclusion Our work suggests a key role for insulin and insulin-related signalling in OCD etiology and — if confirmed by independent studies — could eventually pave the way for the development of novel OCD treatments. PMID:26854754

  1. THEORY AND METHOD FOR WETLAND BOUNDARY DELINEATION

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on the analysis of the subjectivity of wetland boundary criteria and their causes at present, this paper suggested that, under the condition that the mechanism of wetland formation process has not been understood,"black box" method of System Theory can be used to delineate wetland boundaries scientifically. After analyzing the difference of system construction among aquatic habitats, wetlands and uplands, the lower limit of rooted plants was chosen as the lower boundary criterion of wetlands. Because soil diagnostic horizon is the result of the long-term interaction among all environments, and it is less responsive than vegetation to short-term change, soil diagnostic horizon was chosen as the indicator to delineate wetland upper boundary, which lies at the thinning-out point of soil diagnostic horizon. Case study indicated that it was feasible using the lower limit of rooted plants and the thinning-out point of soil diagnostic horizon as criteria to delineate the lower and upper boundaries of wetland. In the study area, the thinning-out line of albic horizon was coincident with the 55.74m contour line, the maximum horizonerror was less than lm, and the maximum vertical error less than 0.04m. The problem on wetland definition always arises on the boundaries. Having delineated wetland boundaries, wetlands can be defined as follows: wetlands are the transitional zones between uplands and deepwater habitats, they are a kind of azonal complex that are inundated or saturated by surface or ground water, with the lower boundary lying at the lower limit of rooted plants, and the upper boundary at the thinning-out line of upland soil diagnostic horizon.

  2. Flow stress anisotropy caused by geometrically necessary boundaries

    DEFF Research Database (Denmark)

    Hansen, N.; Juul Jensen, D.

    1992-01-01

    The microstructural anisotropy of deformed metal is related to the formation of geometrically necessary boundaries such as dense dislocation walls and microbands. These boundaries have a macroscopic orientation with respect to the sample axes and they can resist slip due to a high concentration of...

  3. Tax Unit Boundaries

    Data.gov (United States)

    Kansas Data Access and Support Center — The Statewide GIS Tax Unit boundary file was created through a collaborative partnership between the State of Kansas Department of Revenue Property Valuation...

  4. Minnesota County Boundaries

    Data.gov (United States)

    Minnesota Department of Natural Resources — Minnesota county boundaries derived from a combination of 1:24,000 scale PLS lines, 1:100,000 scale TIGER, 1:100,000 scale DLG, and 1:24,000 scale hydrography...

  5. National Forest Boundaries

    Data.gov (United States)

    Minnesota Department of Natural Resources — This theme shows the USFS national forest boundaries in the state. This data was acquired from the GIS coordinators at both the Chippewa National Forest and the...

  6. State Park Statutory Boundaries

    Data.gov (United States)

    Minnesota Department of Natural Resources — Legislative statutory boundaries for sixty six state parks, six state recreation areas, and eight state waysides. These data are derived principally from DNR's...

  7. Allegheny County Parcel Boundaries

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset contains parcel boundaries attributed with county block and lot number. If viewing this description on the Western Pennsylvania Regional Data Center’s...

  8. Haleakala National Park Boundary

    Data.gov (United States)

    National Park Service, Department of the Interior — The park boundary of Haleakala National Park was digitized from USGS quadrangle maps. Haleakala National Park was established in September 1960. Recent NPS land...

  9. BoundaryOther_SUNIONS

    Data.gov (United States)

    Vermont Center for Geographic Information — BoundaryOther_SUNIONS was intended to provide outlines of all Vermont school supervisory unions for use in displaying demographic data pertinent to each union, and...

  10. Minnesota County Boundaries - lines

    Data.gov (United States)

    Minnesota Department of Natural Resources — Minnesota county boundaries derived from a combination of 1:24,000 scale PLS lines, 1:100,000 scale TIGER, 1:100,000 scale DLG, and 1:24,000 scale hydrography...

  11. NM School District Boundaries

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The dataset represents the boundaries of all public school districts in the state of New Mexico. The source for the data layer is the New Mexico Public Education...

  12. FWS Approved Acquisition Boundaries

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This data layer depicts the external boundaries of lands and waters that are approved for acquisition by the U.S. Fish and Wildlife Service (USFWS) in North...

  13. HUC 8 Boundaries

    Data.gov (United States)

    Kansas Data Access and Support Center — This data set is a digital hydrologic unit boundary that is at the 4-digit, 6-digit, 8-digit, and 11-digit level. The data set was developed by delineating the...

  14. Planetary boundaries: guiding human development on a changing planet

    NARCIS (Netherlands)

    Steffen, W.; Richardson, K.; Rockström, J.; Cornell, S.E.; Fetzer, I.; Bennett, E.; Biggs, R.; Vries, de W.

    2015-01-01

    The planetary boundaries framework defines a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth System. Here, we revise and update the planetary boundaries framework, with a focus on the underpinning biophysical science, based on t

  15. Shifting Institutional Boundaries through Cross-Border Higher Education

    Science.gov (United States)

    Amaral, Alberto; Tavares, Orlanda; Cardoso, Sónia; Sin, Cristina

    2016-01-01

    Cross-border higher education (CBHE) has been changing the organizational boundaries of higher education institutions (HEIs). This study aims to analyze the shifting boundaries of Portuguese HEIs through the lens of the identity concept in organization theories, considering three contexts with different levels of regulation: African…

  16. Campylobacter jejuni CsrA complements an Escherichia coli csrA mutation for the regulation of biofilm formation, motility and cellular morphology but not glycogen accumulation

    OpenAIRE

    Fields Joshua A; Thompson Stuart A

    2012-01-01

    Abstract Background Although Campylobacter jejuni is consistently ranked as one of the leading causes of bacterial diarrhea worldwide, the mechanisms by which C. jejuni causes disease and how they are regulated have yet to be clearly defined. The global regulator, CsrA, has been well characterized in several bacterial genera and is known to regulate a number of independent pathways via a post transcriptional mechanism, but remains relatively uncharacterized in the genus Campylobacter. Previou...

  17. Local boundary migration during recrystallization in pure aluminium

    International Nuclear Information System (INIS)

    Boundary migration during recrystallization has been followed by an ex situ electron channelling contrast technique, and protrusions/retrusions formed locally on recrystallization boundaries have been quantified. The results show that the motion of recrystallization boundaries is much more complex than generally appreciated. Locally protrusions/retrusions can provide a driving force comparable in magnitude to the driving force from the stored energy in the deformed matrix. The stop-go motion of the recrystallization boundaries is also discussed and related to the formation of protrusions and retrusions.

  18. Supersymmetry from boundary conditions

    International Nuclear Information System (INIS)

    We study breaking and restoration of supersymmetry in five-dimensional theories by determining the mass spectrum of fermions from their equations of motion. Boundary conditions can be obtained from either the action principle by extremizing an appropriate boundary action (interval approach) or by assigning parities to the fields (orbifold approach). In the former, fields extend continuously from the bulk to the boundaries, while in the latter the presence of brane mass-terms cause fields to jump when one moves across the branes. We compare the two approaches and in particular we carefully compute the non-trivial jump profiles of the wavefunctions in the orbifold picture for very general brane mass terms. We also include the effect of the Scherk-Schwarz mechanism in either approach and point out that for a suitable tuning of the boundary actions supersymmetry is present for arbitrary values of the Scherk-Schwarz parameter. As an application of the interval formalism we construct bulk and boundary actions for super-Yang-Mills theory. Finally we extend our results to the warped Randall-Sundrum background

  19. Boundary breaking for interdisciplinary learning

    Directory of Open Access Journals (Sweden)

    Adi Kidron

    2015-10-01

    Full Text Available The purpose of this work is to contribute to the body of knowledge on processesby which students develop interdisciplinary understanding of contents, as well as to suggest technology-enhanced means for supporting them in these processes in the context of higher education. In doing so, we suggest a rethinking of three traditional practices that tend to characterise typical higher education instruction: (1 compartmentalisation of disciplines; (2 traditional pedagogy; and (3 traditional hierarchies based on levels of expertise. Our high-level conjecture was that meaningful dialogue with peers and experts supports both the deepening of ideas in one knowledge domain and the formation of connections between ideas from several domains, both of which are required for the development of interdisciplinary understanding. We developed the Boundary Breaking for Interdisciplinary Learning (BBIL model, which harnesses technology to break boundaries between disciplines, learners and organisational levels of hierarchy. Findings indicate that 36 undergraduate students who participated in an interdisciplinary online course that implemented the BBIL model have significantly improved their interdisciplinary understanding of the course contents. This study illustrates how innovative use of available, free and low-cost technology can produce a ‘positive disruption’ in higher education instruction.

  20. Outer Magnetospheric Boundaries Cluster Results

    CERN Document Server

    Paschmann, Goetz; Schwartz, S J

    2006-01-01

    When the stream of plasma emitted from the Sun (the solar wind) encounters Earth's magnetic field, it slows down and flows around it, leaving behind a cavity, the magnetosphere. The magnetopause is the surface that separates the solar wind on the outside from the Earth's magnetic field on the inside. Because the solar wind moves at supersonic speed, a bow shock must form ahead of the magnetopause that acts to slow the solar wind to subsonic speeds. Magnetopause, bow shock and their environs are rich in exciting processes in collisionless plasmas, such as shock formation, magnetic reconnection, particle acceleration and wave-particle interactions. They are interesting in their own right, as part of Earth's environment, but also because they are prototypes of similar structures and phenomena that are ubiquitous in the universe, having the unique advantage that they are accessible to in situ measurements. The boundaries of the magnetosphere have been the target of direct in-situ measurements since the beginning ...

  1. The CRP/FNR family protein Bcam1349 is a c-di-GMP effector that regulates biofilm formation in the respiratory pathogen Burkholderia cenocepacia

    DEFF Research Database (Denmark)

    Fazli, Mustafa; O'Connell, Aileen; Nilsson, Martin; Niehaus, Karsten; Dow, J Maxwell; Givskov, Michael; Ryan, Robert P; Tolker-Nielsen, Tim

    2011-01-01

    defect with physiological c-di-GMP levels. The bcam1349 gene is predicted to encode a transcriptional regulator of the CRP/FNR superfamily. Analyses of purified Bcam1349 protein and truncations demonstrated that it binds c-di-GMP in vitro. The Bcam1349 protein was shown to regulate the production of a...

  2. Probabilistic boundary element method

    Science.gov (United States)

    Cruse, T. A.; Raveendra, S. T.

    1989-01-01

    The purpose of the Probabilistic Structural Analysis Method (PSAM) project is to develop structural analysis capabilities for the design analysis of advanced space propulsion system hardware. The boundary element method (BEM) is used as the basis of the Probabilistic Advanced Analysis Methods (PADAM) which is discussed. The probabilistic BEM code (PBEM) is used to obtain the structural response and sensitivity results to a set of random variables. As such, PBEM performs analogous to other structural analysis codes such as finite elements in the PSAM system. For linear problems, unlike the finite element method (FEM), the BEM governing equations are written at the boundary of the body only, thus, the method eliminates the need to model the volume of the body. However, for general body force problems, a direct condensation of the governing equations to the boundary of the body is not possible and therefore volume modeling is generally required.

  3. Adaptive Sentence Boundary Disambiguation

    CERN Document Server

    Palmer, D D; Palmer, David D.; Hearst, Marti A.

    1994-01-01

    Labeling of sentence boundaries is a necessary prerequisite for many natural language processing tasks, including part-of-speech tagging and sentence alignment. End-of-sentence punctuation marks are ambiguous; to disambiguate them most systems use brittle, special-purpose regular expression grammars and exception rules. As an alternative, we have developed an efficient, trainable algorithm that uses a lexicon with part-of-speech probabilities and a feed-forward neural network. After training for less than one minute, the method correctly labels over 98.5\\% of sentence boundaries in a corpus of over 27,000 sentence-boundary marks. We show the method to be efficient and easily adaptable to different text genres, including single-case texts.

  4. Free-boundary equilibria

    International Nuclear Information System (INIS)

    A self-contained MHD description of the Helias class stellarators is obtained by determining appropriate external currents (coils) producing the Helias vacuum field and by the subsequent computing of the free-boundary equilibrium. Coil configurations are calculated with the NESCOIL code, the free-boundary equilibrium is studied via the NEMEC code, which combines the 3D fixed-boundary VMEC code and the NESTOR code for determining the vacuum field surrounding the plasma. Results for the 5081 Helias configuration, being considered for the W VII-X device are shown. The 5081 is a five-period device with aspect ratio 10 and a rotational transform between 0.8 and 1.0. It is MHD stable up to a beta value of 0.05

  5. Spectrum of local boundary operators from boundary form factor bootstrap

    OpenAIRE

    Szots, M.; Takacs, G.

    2007-01-01

    Using the recently introduced boundary form factor bootstrap equations, we map the complete space of their solutions for the boundary version of the scaling Lee-Yang model and sinh-Gordon theory. We show that the complete space of solutions, graded by the ultraviolet behaviour of the form factors can be brought into correspondence with the spectrum of local boundary operators expected from boundary conformal field theory, which is a major evidence for the correctness of the boundary form fact...

  6. Spectrum of local boundary operators from boundary form factor bootstrap

    CERN Document Server

    Szots, M

    2007-01-01

    Using the recently introduced boundary form factor bootstrap equations, we map the complete space of their solutions for the boundary version of the scaling Lee-Yang model and sinh-Gordon theory. We show that the complete space of solutions, graded by the ultraviolet behaviour of the form factors can be brought into correspondence with the spectrum of local boundary operators expected from boundary conformal field theory, which is a major evidence for the correctness of the boundary form factor bootstrap framework.

  7. Light inhibits gravity-regulated peg formation and asymmetric mRNA accumulation of auxin-inducible CsIAA1 in the cortex of the transition zone in cucumber seedlings

    Science.gov (United States)

    Fujii, Nobuharu; Saito, Yuko; Miyazawa, Yutaka; Takahashi, Hideyuki

    When cucumber seedlings are grown horizontally, a specialized protuberance, termed the peg, develops on the lower side of the transition zone between the hypocotyl and the root. Gravimorphogenesis regulates the lateral positioning of the peg in the transition zone and it has been suggested that auxin plays an important role in peg formation in cucumber seedlings. Here, we found that light inhibited auxin-regulated peg formation. In the transition zone of horizontally positioned cucumber seedlings grown in the dark, we detected an asymmetric accumulation of mRNA from the auxin-inducible gene CsIAA1 in the epidermis and cortex. However, in seedlings grown under illumination, this asymmetry was greatly reduced. In dark- and light-grown seedlings, application of 10 -3 M indole-3-acetic acid induced peg formation on both the lower and upper sides of the transition zone. These results suggest that light inhibits peg formation via modification of auxin distribution and/or levels in the transition zone of cucumber seedlings.

  8. Function and Evolution of a MicroRNA That Regulates a Ca2+-ATPase and Triggers the Formation of Phased Small Interfering RNAs in Tomato Reproductive Growth[W][OA

    Science.gov (United States)

    Wang, Ying; Itaya, Asuka; Zhong, Xuehua; Wu, Yang; Zhang, Jianfeng; van der Knaap, Esther; Olmstead, Richard; Qi, Yijun; Ding, Biao

    2011-01-01

    MicroRNAs (miRNAs) regulate a wide variety of biological processes in most eukaryotes. We investigated the function and evolution of miR4376 in the family Solanaceae. We report that the 22-nucleotide miR4376 regulates the expression of an autoinhibited Ca2+-ATPase, tomato (Solanum lycopersicum) ACA10, which plays a critical role in tomato reproductive growth. Deep phylogenetic mapping suggested (1) an evolution course of MIR4376 loci and posttranscriptional processing of pre-miR4376 as a likely limiting step for the evolution of miR4376, (2) an independent phylogenetic origin of the miR4376 target site in ACA10 homologs, and (3) alternative splicing as a possible mechanism of eliminating such a target in some ACA10 homologs. Furthermore, miR4376 triggers the formation of phased small interfering RNAs (siRNAs) from Sl ACA10 and its Solanum tuberosum homolog. Together, our data provide experimental evidence of miRNA-regulated expression of universally important Ca2+-ATPases. The miR4376-regulated expression of ACA10 itself, and possibly also the associated formation of phased siRNAs, may function as a novel layer of molecular mechanisms underlying tomato reproductive growth. Finally, our data suggest that the stochastic emergence of a miRNA-target gene combination involves multiple molecular events at the genomic, transcriptional, and posttranscriptional levels that may vary drastically in even closely related species. PMID:21917547

  9. Intracellular adenosine 3',5'-phosphate formation is essential for down-regulation of surface adenosine 3',5'-phosphate receptors in Dictyostelium

    OpenAIRE

    Van Haastert, Peter J. M.

    1994-01-01

    Dictyostelium discoideum cells contain cell surface cyclic AMP (cAMP) receptors that bind cAMP as a first messenger and intracellular cAMP receptors that bind cAMP as a second messenger. Prolonged incubation of Dictyostelium cells with cAMP induces a sequential process of phosphorylation, sequestration and down-regulation of the surface receptors. The role of intracellular cAMP in down-regulation of surface receptors was investigated. Down-regulation of receptors does not occur under conditio...

  10. Challenging the Boundaries

    DEFF Research Database (Denmark)

    Nørgaard, Nina

    2004-01-01

    To many people, challenging the boundaries between the traditional disciplines in foreign language studies means doing cultural studies. The aim of this article is to pull in a different direction by suggesting how the interface between linguistics and literature may be another fertile field to e...

  11. Boundaries of the universe

    CERN Document Server

    Glasby, John S

    2013-01-01

    The boundaries of space exploration are being pushed back constantly, but the realm of the partially understood and the totally unknown is as great as ever. Among other things this book deals with astronomical instruments and their application, recent discoveries in the solar system, stellar evolution, the exploding starts, the galaxies, quasars, pulsars, the possibilities of extraterrestrial life and relativity.

  12. Dynamic regulation of GacA in type III secretion, pectinase gene expression, pellicle formation, and pathogenicity of Dickeya dadantii (Erwinia chrysanthemi 3937).

    Science.gov (United States)

    Yang, Shihui; Peng, Quan; Zhang, Qiu; Yi, Xuan; Choi, Chang Jae; Reedy, Ralph M; Charkowski, Amy O; Yang, Ching-Hong

    2008-01-01

    Dickeya dadantii (Erwinia chrysanthemi 3937) secretes exoenzymes, including pectin-degrading enzymes, leading to the loss of structural integrity of plant cell walls. A type III secretion system (T3SS) is essential for full virulence of this bacterium within plant hosts. The GacS/GacA two-component signal transduction system participates in important biological roles in several gram-negative bacteria. In this study, a gacA deletion mutant (Ech137) of D. dadantii was constructed to investigate the effect of this mutation on pathogenesis and other phenotypes. Compared with wild-type D. dadantii, Ech137 had a delayed biofilm-pellicle formation. The production of pectate lyase (Pel), protease, and cellulase was diminished in Ech137 compared with the wild-type cells. Reduced transcription of two endo-Pel genes, pelD and pelL, was found in Ech137 using a green fluorescence protein-based fluorescence-activated cell sorter promoter activity assay. In addition, the transcription of T3SS genes dspE (an effector), hrpA (a structural protein of the T3SS pilus), and hrpN (a T3SS harpin) was reduced in Ech137. A lower amount of rsmB regulatory RNA was found in gacA mutant Ech137 compared with the wild-type bacterium by quantitative reverse-transcription polymerase chain reaction. Compared with wild-type D. dadantii, a lower amount of hrpL mRNA was observed in Ech137 at 12 h grown in medium. Although the role of RsmA, rsmB, and RsmC in D. dadantii is not clear, from the regulatory pathway revealed in E. carotovora, the lower expression of dspE, hrpA, and hrpN in Ech137 may be due to a post-transcriptional regulation of hrpL through the Gac-Rsm regulatory pathway. Consequently, the reduced exoenzyme production and Pel gene expression in the mutant may be sue partially to the regulatory role of rsmB-RsmA on exoenzyme expression. Similar to in vitro results, a lower expression of T3SS and pectinase genes of Ech137 also was observed in bacterial cells inoculated into Saintpaulia

  13. On the Ekman instability at the core-mantle boundary

    Science.gov (United States)

    Chkhetiani, O. G.; Shalimov, S. L.

    2016-05-01

    It is shown that the instability of turbulent flows with Ekman velocity profiles in the vicinity of the core-mantle boundary leads to the formation of horizontally oriented circulating roll structures. The geophysical implications of the presence of such structures in the liquid core are explored, namely, the formation of the hot zones with enhanced conductivity and their influence on geomagnetic reversals.

  14. Wisp2/CCN5 up-regulated in the central nervous system of GM3-only mice facilitates neurite formation in Neuro2a cells via integrin-Akt signaling

    Energy Technology Data Exchange (ETDEWEB)

    Ohkawa, Yuki, E-mail: tomilbio@med.nagoya-u.ac.jp [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan); Ohmi, Yuhsuke, E-mail: ooumi82@med.nagoya-u.ac.jp [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan); Tajima, Orie, E-mail: oriet@isc.chubu.ac.jp [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan); Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, 1200 Matsumoto-cho, Kasugai 487-8501 (Japan); Yamauchi, Yoshio, E-mail: yyoshio@med.nagoya-u.ac.jp [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan); Furukawa, Keiko, E-mail: keikofu@isc.chubu.ac.jp [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan); Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, 1200 Matsumoto-cho, Kasugai 487-8501 (Japan); Furukawa, Koichi, E-mail: koichi@med.nagoya-u.ac.jp [Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065 (Japan)

    2011-08-05

    Highlights: {yields} Wisp2/CCN5 was up-regulated in nervous tissues of GM3-only mutant mice. {yields} Wisp2/CCN5 was found in neurons more strongly in the mutant mice. {yields} Wisp2/CCN5 induces Akt phosphorylation via integrins and facilitates neurite formation. {yields} Wisp2/CCN5 conferred resistance to H{sub 2}O{sub 2}-induced apoptosis. {yields} Up-regulation of Wisp2/CCN5 in GM3-only mice seemed for protection of brains from neurodegeneration. -- Abstract: Wisp2/CCN5 belongs to CCN family proteins which are involved in cell proliferation, angiogenesis, tumorigenesis and wound healing. Although a number of studies on the roles of Wisp2/CCN5 in cancers have been reported, no study on the expression and function of Wisp2/CCN5 in the central nervous system has been reported. In this study, we focused on Wisp2/CCN5 that was up-regulated in nervous tissues in GM3-only mice. Over-expression of Wisp2/CCN5 enhanced neurite outgrowth potently after serum withdrawal with increased phosphorylation levels of Akt and ERKs. When cells were cultured with recombinant Wisp2/CCN5 proteins, more and longer neurites were formed than in the controls. Thus, we demonstrated for the first time that Wisp2/CCN5 facilitates neurite formation in a mouse neuroblastoma cell line, Neuro2a. Akt phosphorylation induced by recombinant Wisp2/CCN5 was suppressed after knockdown of integrin {beta}1. Moreover, Wisp2/CCN5-over-expressing cells were resistant to apoptosis induced by H{sub 2}O{sub 2}. These results suggested that secreted Wisp2/CCN5 induces Akt and ERK phosphorylation via integrins, and consequently facilitates neurite formation and conferred resistance to apoptosis. Up-regulation of Wisp2/CCN5 in GM3-only mice should be, therefore, a reaction to protect nervous tissues from neurodegeneration caused by ganglioside deficiency.

  15. Probing grain boundary sink strength at the nanoscale: Energetics and length scales of vacancy and interstitial absorption by grain boundaries in α-Fe

    Energy Technology Data Exchange (ETDEWEB)

    Tschopp, Mark A.; Solanki, K. N.; Gao, Fei; Sun, Xin; Khaleel, Mohammad A.; Horstemeyer, Mark

    2012-02-10

    The energetics and length scales associated with the interaction between point defects (vacancies and self-interstitial atoms) and grain boundaries in bcc Fe was explored. Molecular statics simulations were used to generate a grain boundary structure database that contained {approx}170 grain boundaries with varying tilt and twist character. Then, vacancy and self-interstitial atom formation energies were calculated at all potential grain boundary sites within 15 {angstrom} of the boundary. The present results provide detailed information about the interaction energies of vacancies and self-interstitial atoms with symmetric tilt grain boundaries in iron and the length scales involved with absorption of these point defects by grain boundaries. Both low- and high-angle grain boundaries were effective sinks for point defects, with a few low-{Sigma} grain boundaries (e.g., the {Sigma}3{l_brace}112{r_brace} twin boundary) that have properties different from the rest. The formation energies depend on both the local atomic structure and the distance from the boundary center. Additionally, the effect of grain boundary energy, disorientation angle, and {Sigma} designation on the boundary sink strength was explored; the strongest correlation occurred between the grain boundary energy and the mean point defect formation energies. Based on point defect binding energies, interstitials have {approx}80% more grain boundary sites per area and {approx}300% greater site strength than vacancies. Last, the absorption length scale of point defects by grain boundaries is over a full lattice unit larger for interstitials than for vacancies (mean of 6-7 {angstrom} versus 10-11 {angstrom} for vacancies and interstitials, respectively).

  16. Probing grain boundary sink strength at the nanoscale: Energetics and length scales of vacancy and interstitial absorption by grain boundaries in α-Fe

    Science.gov (United States)

    Tschopp, M. A.; Solanki, K. N.; Gao, F.; Sun, X.; Khaleel, M. A.; Horstemeyer, M. F.

    2012-02-01

    The energetics and length scales associated with the interaction between point defects (vacancies and self-interstitial atoms) and grain boundaries in bcc Fe was explored. Molecular statics simulations were used to generate a grain boundary structure database that contained ≈170 grain boundaries with varying tilt and twist character. Then, vacancy and self-interstitial atom formation energies were calculated at all potential grain boundary sites within 15 Å of the boundary. The present results provide detailed information about the interaction energies of vacancies and self-interstitial atoms with symmetric tilt grain boundaries in iron and the length scales involved with absorption of these point defects by grain boundaries. Both low- and high-angle grain boundaries were effective sinks for point defects, with a few low-Σ grain boundaries (e.g., the Σ3{112} twin boundary) that have properties different from the rest. The formation energies depend on both the local atomic structure and the distance from the boundary center. Additionally, the effect of grain boundary energy, disorientation angle, and Σ designation on the boundary sink strength was explored; the strongest correlation occurred between the grain boundary energy and the mean point defect formation energies. Based on point defect binding energies, interstitials have ≈80% more grain boundary sites per area and ≈300% greater site strength than vacancies. Last, the absorption length scale of point defects by grain boundaries is over a full lattice unit larger for interstitials than for vacancies (mean of 6-7 Å versus 10-11 Å for vacancies and interstitials, respectively).

  17. Grain Boundary Segregation in Metals

    CERN Document Server

    Lejcek, Pavel

    2010-01-01

    Grain boundaries are important structural components of polycrystalline materials used in the vast majority of technical applications. Because grain boundaries form a continuous network throughout such materials, their properties may limit their practical use. One of the serious phenomena which evoke these limitations is the grain boundary segregation of impurities. It results in the loss of grain boundary cohesion and consequently, in brittle fracture of the materials. The current book deals with fundamentals of grain boundary segregation in metallic materials and its relationship to the grain boundary structure, classification and other materials properties.

  18. Reactor pressure boundary materials

    International Nuclear Information System (INIS)

    With a long-term operation of nuclear power plants, the component materials are degraded under severe reactor conditions such as neutron irradiation, high temperature, high pressure and corrosive environment. It is necessary to establish the reliable and practical technologies for improving and developing the component materials and for evaluating the mechanical properties. Especially, it is very important to investigate the technologies for reactor pressure boundary materials such as reactor vessel and pipings in accordance with their critical roles. Therefore, this study was focused on developing and advancing the microstructural/micro-mechanical evaluation technologies, and on evaluating the neutron irradiation characteristics and radiation effects analysis technology of the reactor pressure boundary materials, and also on establishing a basis of nuclear material property database

  19. Exploring system boundaries

    OpenAIRE

    Webb, Tom

    2013-01-01

    Autopoiesis is normally considered to be the systems theory in law. In this paper complexity theory is presented as an alternative systems approach. In order to position complexity theory as a plausible alternative to autopoiesis I discuss the differing understanding of boundary within each theory, and use this as a vehicle to critique autopoiesis. My critique is situated within systems theory thinking but is external to both autopoiesis and complexity theory (although I must oscillate betwee...

  20. Boundary transfer matrices and boundary quantum KZ equations

    Energy Technology Data Exchange (ETDEWEB)

    Vlaar, Bart, E-mail: Bart.Vlaar@nottingham.ac.uk [School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

    2015-07-15

    A simple relation between inhomogeneous transfer matrices and boundary quantum Knizhnik-Zamolodchikov (KZ) equations is exhibited for quantum integrable systems with reflecting boundary conditions, analogous to an observation by Gaudin for periodic systems. Thus, the boundary quantum KZ equations receive a new motivation. We also derive the commutativity of Sklyanin’s boundary transfer matrices by merely imposing appropriate reflection equations, in particular without using the conditions of crossing symmetry and unitarity of the R-matrix.

  1. The open boundary equation

    Directory of Open Access Journals (Sweden)

    D. Diederen

    2015-06-01

    Full Text Available We present a new equation describing the hydrodynamics in infinitely long tidal channels (i.e., no reflection under the influence of oceanic forcing. The proposed equation is a simple relationship between partial derivatives of water level and velocity. It is formally derived for a progressive wave in a frictionless, prismatic, tidal channel with a horizontal bed. Assessment of a large number of numerical simulations, where an open boundary condition is posed at a certain distance landward, suggests that it can also be considered accurate in the more natural case of converging estuaries with nonlinear friction and a bed slope. The equation follows from the open boundary condition and is therefore a part of the problem formulation for an infinite tidal channel. This finding provides a practical tool for evaluating tidal wave dynamics, by reconstructing the temporal variation of the velocity based on local observations of the water level, providing a fully local open boundary condition and allowing for local friction calibration.

  2. Curcumin-induced fibroblast apoptosis and in vitro wound contraction are regulated by antioxidants and heme oxygenase: implications for scar formation.

    NARCIS (Netherlands)

    Scharstuhl, A.; Mutsaers, H.A.M.; Pennings, S.W.C.; Szarek, W.A.; Russel, F.G.M.; Wagener, F.A.D.T.G.

    2009-01-01

    Fibroblast apoptosis plays a crucial role in normal and pathological scar formation and therefore we studied whether the putative apoptosis-inducing factor curcumin affects fibroblast apoptosis and may function as a novel therapeutic. We show that 25-microM curcumin causes fibroblast apoptosis and t

  3. The causal boundary and its relations with the conformal boundary

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, J, E-mail: jherrera@agt.cie.uma.e [Departamento de Algebra, GeometrIa y TopologIa, Facultad de Ciencias, Universidad de Malaga, Campus Teatinos, 29071 Malaga (Spain)

    2010-05-01

    Our aim in this note is to present the results (obtained in [2]) which ensure that, under certain regularity conditions, the conformal boundary becomes equal to the causal boundary, not only as a point set, but in a topological and chronological level. In particular, under these conditions the conformal boundary becomes a powerful tool to compute the causal one.

  4. Genetic interaction between GROWTH-REGULATING FACTOR and CUP-SHAPED COTYLEDON in organ separation

    OpenAIRE

    Lee, Byung Ha; Jeon, Jae Og; Lee, Myeong Min; Kim, Jeong Hoe

    2015-01-01

    The Arabidopsis thaliana GROWTH-REGULATING FACTOR (GRF) gene family comprises 9 members and encodes a class of transcription factors. We previously demonstrated that GRF genes played an essential role in formation of the boundary region between cotyledons, since their loss-of-function mutants developed fused cotyledons. Our present study shows that the grf mutants display fused floral organs as well. Such fusion phenotypes of embryonic and post-embryonic floral organs are highly reminiscent o...

  5. Regulation of Autotrophic and Heterotrophic Metabolism in Pseudomonas oxalaticus OX1. Growth on Fructose and on Mixtures of Fructose and Formate in Batch and Continuous Cultures

    NARCIS (Netherlands)

    Dijkhuizen, L.; Harder, W.

    1984-01-01

    In Pseudomonas oxalaticus the synthesis of enzymes involved in autotrophic CO2 fixation via the Calvin cycle is regulated by repression/derepression. During growth of the organism on fructose alone, the synthesis of ribulosebisphosphate carboxylase (RuBPCase) remained fully repressed, both in batch

  6. Bristled shark skin: a microgeometry for boundary layer control?

    Energy Technology Data Exchange (ETDEWEB)

    Lang, A W; Hidalgo, P; Westcott, M [Aerospace Engineering and Mechanics Department, University of Alabama, Box 870280, Tuscaloosa, AL 35487 (United States); Motta, P [Biology Department, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620 (United States)], E-mail: alang@eng.ua.edu

    2008-12-01

    There exists evidence that some fast-swimming shark species may have the ability to bristle their scales during fast swimming. Experimental work using a water tunnel facility has been performed to investigate the flow field over and within a bristled shark skin model submerged within a boundary layer to deduce the possible boundary layer control mechanisms being used by these fast-swimming sharks. Fluorescent dye flow visualization provides evidence of the formation of embedded cavity vortices within the scales. Digital particle image velocimetry (DPIV) data, used to evaluate the cavity vortex formation and boundary layer characteristics close to the surface, indicate increased momentum in the slip layer forming above the scales. This increase in flow velocity close to the shark's skin is indicative of boundary layer control mechanisms leading to separation control and possibly transition delay for the bristled shark skin microgeometry.

  7. Collagen IX is required for the integrity of collagen II fibrils and the regulation of vascular plexus formation in Zebrafish caudal fins

    OpenAIRE

    Huang, Cheng-chen; Wang, Tai-Chuan; Lin, Bo-Hung; Wang, Yi-Wen; Johnson, Stephen L.; Yu, John

    2009-01-01

    Capillary plexuses form during both vasculogenesis and angiogenesis and are remodeled into mature vessel types and patterns which are delicately orchestrated with the sizes and shapes of other tissues and organs. We isolated a zebrafish mutation named prp (for persistent plexus) that causes persistent formation of vascular plexuses in the caudal fins and consequent mispatterning of bony fin rays and the fin shape. Detailed analyses revealed that the prp mutation causes a significant reduction...

  8. A Ploidy-Sensitive Mechanism Regulates Aperture Formation on the Arabidopsis Pollen Surface and Guides Localization of the Aperture Factor INP1.

    Directory of Open Access Journals (Sweden)

    Sarah H Reeder

    2016-05-01

    Full Text Available Pollen presents a powerful model for studying mechanisms of precise formation and deposition of extracellular structures. Deposition of the pollen wall exine leads to the generation of species-specific patterns on pollen surface. In most species, exine does not develop uniformly across the pollen surface, resulting in the formation of apertures-openings in the exine that are species-specific in number, morphology and location. A long time ago, it was proposed that number and positions of apertures might be determined by the geometry of tetrads of microspores-the precursors of pollen grains arising via meiotic cytokinesis, and by the number of last-contact points between sister microspores. We have tested this model by characterizing Arabidopsis mutants with ectopic apertures and/or abnormal geometry of meiotic products. Here we demonstrate that contact points per se do not act as aperture number determinants and that a correct geometric conformation of a tetrad is neither necessary nor sufficient to generate a correct number of apertures. A mechanism sensitive to pollen ploidy, however, is very important for aperture number and positions and for guiding the aperture factor INP1 to future aperture sites. In the mutants with ectopic apertures, the number and positions of INP1 localization sites change depending on ploidy or ploidy-related cell size and not on INP1 levels, suggesting that sites for aperture formation are specified before INP1 is brought to them.

  9. A Ploidy-Sensitive Mechanism Regulates Aperture Formation on the Arabidopsis Pollen Surface and Guides Localization of the Aperture Factor INP1.

    Science.gov (United States)

    Reeder, Sarah H; Lee, Byung Ha; Fox, Ronald; Dobritsa, Anna A

    2016-05-01

    Pollen presents a powerful model for studying mechanisms of precise formation and deposition of extracellular structures. Deposition of the pollen wall exine leads to the generation of species-specific patterns on pollen surface. In most species, exine does not develop uniformly across the pollen surface, resulting in the formation of apertures-openings in the exine that are species-specific in number, morphology and location. A long time ago, it was proposed that number and positions of apertures might be determined by the geometry of tetrads of microspores-the precursors of pollen grains arising via meiotic cytokinesis, and by the number of last-contact points between sister microspores. We have tested this model by characterizing Arabidopsis mutants with ectopic apertures and/or abnormal geometry of meiotic products. Here we demonstrate that contact points per se do not act as aperture number determinants and that a correct geometric conformation of a tetrad is neither necessary nor sufficient to generate a correct number of apertures. A mechanism sensitive to pollen ploidy, however, is very important for aperture number and positions and for guiding the aperture factor INP1 to future aperture sites. In the mutants with ectopic apertures, the number and positions of INP1 localization sites change depending on ploidy or ploidy-related cell size and not on INP1 levels, suggesting that sites for aperture formation are specified before INP1 is brought to them. PMID:27177036

  10. A Ploidy-Sensitive Mechanism Regulates Aperture Formation on the Arabidopsis Pollen Surface and Guides Localization of the Aperture Factor INP1

    Science.gov (United States)

    Reeder, Sarah H.; Lee, Byung Ha; Fox, Ronald; Dobritsa, Anna A.

    2016-01-01

    Pollen presents a powerful model for studying mechanisms of precise formation and deposition of extracellular structures. Deposition of the pollen wall exine leads to the generation of species-specific patterns on pollen surface. In most species, exine does not develop uniformly across the pollen surface, resulting in the formation of apertures–openings in the exine that are species-specific in number, morphology and location. A long time ago, it was proposed that number and positions of apertures might be determined by the geometry of tetrads of microspores–the precursors of pollen grains arising via meiotic cytokinesis, and by the number of last-contact points between sister microspores. We have tested this model by characterizing Arabidopsis mutants with ectopic apertures and/or abnormal geometry of meiotic products. Here we demonstrate that contact points per se do not act as aperture number determinants and that a correct geometric conformation of a tetrad is neither necessary nor sufficient to generate a correct number of apertures. A mechanism sensitive to pollen ploidy, however, is very important for aperture number and positions and for guiding the aperture factor INP1 to future aperture sites. In the mutants with ectopic apertures, the number and positions of INP1 localization sites change depending on ploidy or ploidy-related cell size and not on INP1 levels, suggesting that sites for aperture formation are specified before INP1 is brought to them. PMID:27177036

  11. Boundaries and Boundary Marks - Substantive Cultural Heritage of Extensive Importance

    Science.gov (United States)

    Waldhaeusl, P.; Koenig, H.; Mansberger, R.

    2015-08-01

    The Austrian Society for surveying and Geoinformation (ASG) has proposed to submit "Boundaries and Boundary Marks" for the UNESCO World Heritage title. It was time that boundaries, borders and limits of all types as well as ownership rights would find the proper attention in the global public. Landmarks symbolize the real property and the associated rights and obligations, in a figurative sense, the property generally and all legal limits. A democratic state of law is impossible at today's population density without a functioning land administration system with surveying and jurisdiction. As monumental World Heritage representatives of the geodetic artwork "Boundaries and Boundary Marks" are specifically proposed: remaining monuments of the original cadastral geodetic network, the first pan-Austrian surveying headquarters in Vienna, and a specific selection of outstanding boundary monuments. Landmarks are monuments to the boundaries which separate rights and obligations, but also connect the neighbors peacefully after written agreement. "And cursed be he who does not respect the boundaries" you wrote already 3000 years ago. Boundaries and Boundary Marks are a real thing; they all belong to the tangible or material heritage of human history. In this context also the intangible heritage is discussed. This refers to oral tradition and expressions, performing arts; social practices, rituals and festive events; as well as to knowledge and practices handling nature and the universe. "Boundaries and Boundary Marks" do not belong to it, but clearly to the material cultural world heritage. "Boundary and Boundary Marks" is proposed to be listed according to the criteria (ii),(iv),(vi).

  12. Open boundary molecular dynamics

    Science.gov (United States)

    Delgado-Buscalioni, R.; Sablić, J.; Praprotnik, M.

    2015-09-01

    This contribution analyzes several strategies and combination of methodologies to perform molecular dynamic simulations in open systems. Here, the term open indicates that the total system has boundaries where transfer of mass, momentum and energy can take place. This formalism, which we call Open Boundary Molecular Dynamics (OBMD), can act as interface of different schemes, such as Adaptive Resolution Scheme (AdResS) and Hybrid continuum-particle dynamics to link atomistic, coarse-grained (CG) and continuum (Eulerian) fluid dynamics in the general framework of fluctuating Navier-Stokes equations. The core domain of the simulation box is solved using all-atom descriptions. The CG layer introduced using AdResS is located at the outer part of the open box to make feasible the insertion of large molecules into the system. Communications between the molecular system and the outer world are carried out in the outer layers, called buffers. These coupling preserve momentum and mass conservation laws and can thus be linked with Eulerian hydro- dynamic solvers. In its simpler form, OBMD allows, however, to impose a local pressure tensor and a heat flux across the system's boundaries. For a one component molecular system, the external normal pressure and temperature determine the external chemical potential and thus the independent parameters of a grand-canonical ensemble simulation. Extended ensembles under non-equilibrium stationary states can also be simulated as well as time dependent forcings (e.g. oscillatory rheology). To illustrate the robustness of the combined OBMD-AdResS method, we present simulations of star-polymer melts at equilibrium and in sheared flow.

  13. Theoretical investigation on shocklets in compressible boundary layers

    Institute of Scientific and Technical Information of China (English)

    袁湘江; 刘智勇; 沈洁; 李国良

    2014-01-01

    By the shock relationships, the wavy characteristics and the forming condi-tions of a shock wave are analyzed. The wavy characteristics of an Euler system are stud-ied theoretically. The present research focuses on the wavy characteristics of Tollmien-Schlichting (T-S) waves, the excitation conditions of shocklets in compressible boundary layers, and the viscous effect on shock. The possibility of existence of shocklets in the compressible boundary layer and the physical mechanism of formation are theoretically interpreted.

  14. Beyond the Boundary

    DEFF Research Database (Denmark)

    Gorm Hansen, Birgitte

    2012-01-01

    . Drawing on interviews with the head of a research center in plant biology, this article argues that biology and biotech are symbionts. In order to be viable and productive, symbiosis needs to be carefully managed and given room for divergence within mutual dependence. This process does not take place as...... the negotiation of a preexisting science-industry boundary. Rather, viability is obtained through a strategy of circumventing the science-industry food chain and sequestering biotech components within the research center. Symbiosis allows academic scientists to do biology while at the same time...

  15. Beyond the Boundary

    DEFF Research Database (Denmark)

    Gorm Hansen, Birgitte

    2011-01-01

    . Drawing on interviews with the head of a research center in plant biology, this article argues that biology and biotech are "symbionts". In order to be viable and productive, symbiosis needs to be carefully managed and given room for divergence within mutual dependence. This process does not take place as...... the negotiation of a preexisting science-industry boundary. Rather, viability is obtained through a strategy of "circumventing" the science-industry food chain and "sequestering" biotech components within the research center. Symbiosis allows academic scientists to do biology while at the same time...

  16. The Boundaries of Fictio

    Directory of Open Access Journals (Sweden)

    Yulia Ivanova

    2014-07-01

    Full Text Available This essay surveys four articles of the section dedicated to the boundaries of fiction in literature, scientific discourse, and other areas of human creativity. The section is supposed to contribute to the study of a broad range of the problems of literary theory, such as the interaction between literature and other social practices, resulting in the creation of a particular discourse of ‘reality’ and ‘objectivity’, and the highly controversial issue of the relationship between ‘material’ and ‘form’ in the literary text.

  17. Developing grain boundary diagrams for multicomponent alloys

    International Nuclear Information System (INIS)

    Impurity-based, premelting-like, intergranular films (IGFs, a common type of grain boundary complexion) can form in various materials and influence sintering, creep, and microstructure development. A thermodynamic framework is presented to forecast the formation and stability of these premelting-like grain boundary complexions (a.k.a. interfacial “phases” that are thermodynamically two dimensional) in multicomponent alloys to consider the interactions of multiple alloying elements. Key thermodynamic parameters that control the interfacial segregation and disordering behaviors have been identified and systematically examined. Subsequently, ternary and quaternary grain boundary diagrams have been computed and used to forecast the sintering behaviors of W–Ni–M (M = Fe, Co, Cr, Zr, Nb and Ti) and Mo–Si–B–M (M = Ni, Co and Fe) systems. This work supports a long-range scientific goal of extending bulk computational thermodynamics and CALPHAD methods to interfaces and developing grain boundary complexion (interfacial “phase”) diagrams as extensions to bulk phase diagrams, which can be a generally useful materials science tool

  18. Increased renal methylglyoxal formation with down-regulation of PGC-1α-FBPase pathway in cystathionine γ-lyase knockout mice.

    Directory of Open Access Journals (Sweden)

    Ashley A Untereiner

    Full Text Available We have previously reported that hydrogen sulfide (H(2S, a gasotransmitter and vasodilator has cytoprotective properties against methylglyoxal (MG, a reactive glucose metabolite associated with diabetes and hypertension. Recently, H(2S was shown to up-regulate peroxisome proliferator-activated receptor-γ coactivator (PGC-1α, a key gluconeogenic regulator that enhances the gene expression of the rate-limiting gluconeogenic enzyme, fructose-1,6-bisphosphatase (FBPase. Thus, we sought to determine whether MG levels and gluconeogenic enzymes are altered in kidneys of 6-22 week-old cystathionine γ-lyase knockout (CSE(-/-; H(2S-producing enzyme male mice. MG levels were determined by HPLC. Plasma glucose levels were measured by an assay kit. Q-PCR was used to measure mRNA levels of PGC-1α and FBPase-1 and -2. Coupled-enzymatic assays were used to determine FBPase activity, or triosephosphate levels. Experimental controls were either age-matched wild type mice or untreated rat A-10 cells. Interestingly, we observed a significant decrease in plasma glucose levels along with a significant increase in plasma MG levels in all three age groups (6-8, 14-16, and 20-22 week-old of the CSE(-/- mice. Indeed, renal MG and triosephosphates were increased, whereas renal FBPase activity, along with its mRNA levels, were decreased in the CSE(-/- mice. The decreased FBPase activity was accompanied by lower levels of its product, fructose-6-phosphate, and higher levels of its substrate, fructose-1,6-bisphosphate in renal extracts from the CSE(-/- mice. In agreement, PGC-1α mRNA levels were also significantly down-regulated in 6-22 week-old CSE(-/- mice. Furthermore, FBPase-1 and -2 mRNA levels were reduced in aorta tissues from CSE(-/- mice. Administration of NaHS, a H(2S donor, increased the gene expression of PGC-1α and FBPase-1 and -2 in cultured rat A-10 cells. In conclusion, overproduction of MG in CSE(-/- mice is due to a H(2S-mediated down-regulation of

  19. The Hale solar sector boundary

    Science.gov (United States)

    Svalgaard, L.; Wilcox, J. M.

    1976-01-01

    A Hale solar-sector boundary is defined as that half (northern hemisphere or southern hemisphere) of a sector boundary in which the change of sector-magnetic-field polarity is the same as the change of polarity from a preceding spot to a following spot. Above a Hale sector boundary the green corona has maximum brightness, while above a non-Hale boundary the green corona has a minimum brightness. The Hale portion of a photospheric sector boundary tends to have maximum magnetic-field strength, while the non-Hale portion has minimum field strength.

  20. The Hale solar sector boundary

    International Nuclear Information System (INIS)

    A Hale solar sector boundary is defined as the half (northern hemisphere or southern hemisphere) of a sector boundary in which the change of sector magnetic field polarity is the same as the change of polarity from a preceding spot to a following spot. Above a Hale sector boundary the green corona has maximum brightness, while above a non-Hale boundary the green corona has a minimum brightness. The Hale portion of a photospheric sector boundary tends to have maximum magnetic field strength, while the non-Hale portion has minimum field strength. (Auth.)