1,904 research outputs found

    A Human Torque Teno Virus Encodes a MicroRNA That Inhibits Interferon Signaling

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    Rodney P. Kincaid, James M. Burke, Jennifer C. Cox, Christopher S. Sullivan, The University of Texas at Austin, Molecular Genetics and Microbiology, Austin, Texas, United States of AmericaEthel-Michele de Villiers, Division for the Characterization of Tumorviruses, Deutsches Krebsforschungszentrum, Heidelberg, GermanyTorque teno viruses (TTVs) are a group of viruses with small, circular DNA genomes. Members of this family are thought to ubiquitously infect humans, although causal disease associations are currently lacking. At present, there is no understanding of how infection with this diverse group of viruses is so prevalent. Using a combined computational and synthetic approach, we predict and identify miRNA-coding regions in diverse human TTVs and provide evidence for TTV miRNA production in vivo. The TTV miRNAs are transcribed by RNA polymerase II, processed by Drosha and Dicer, and are active in RISC. A TTV mutant defective for miRNA production replicates as well as wild type virus genome; demonstrating that the TTV miRNA is dispensable for genome replication in a cell culture model. We demonstrate that a recombinant TTV genome is capable of expressing an exogenous miRNA, indicating the potential utility of TTV as a small RNA vector. Gene expression profiling of host cells identifies N-myc (and STAT) interactor (NMI) as a target of a TTV miRNA. NMI transcripts are directly regulated through a binding site in the 3′UTR. SiRNA knockdown of NMI contributes to a decreased response to interferon signaling. Consistent with this, we show that a TTV miRNA mediates a decreased response to IFN and increased cellular proliferation in the presence of IFN. Thus, we add Annelloviridae to the growing list of virus families that encode miRNAs, and suggest that miRNA-mediated immune evasion can contribute to the pervasiveness associated with some of these viruses.This work was supported by grants RO1AI077746 from the National Institutes of Health, RP110098 from the Cancer Prevention and Research Institute of Texas, a Burroughs Wellcome Investigators in Pathogenesis Award to CSS, a UT Austin Powers Graduate Fellowship to RPK, a UT Austin Institute for Cellular and Molecular Biology fellowship, and the DKFZ for EMdV. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Molecular BiosciencesMicrobiologyEmail: [email protected]

    Additive Main Effects and Multiplicative Interactions (AMMI) and genotype by environment interaction (GGE) biplot analyses aid selection of high yielding and adapted finger millet varieties

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    Background and justification: Lack of stable high yielding cultivars is one of the major bottlenecks for production and productivity of finger millets in Ethiopia. Identification of adaptable, stable and high yielding genotypes under varying environmental conditions prior to release as a cultivar is the first and foremost steps for plant breedingr and this has direct bearing on the adoption of the variety, its productivity and total production of the crop.Objective: The major objectives of the present study were to (i) assess the stability and yield performance of advanced finger millet genotypes  evaluated in multiple environments, and (ii) identify stable high yieldingcandidate cultivar (s) for possible release using different statistical tools.Material and methods: A total of 30 advanced finger millet genotypes were evaluated against two standard checks (Gute and Taddese) across four locations (Arsi Negele, Assosa, Bako and Gute) in 2012 and 2013 main cropping seasons. The trial was arranged in a randomized complete block design (RCBD) replicated three times.Summary result and application of the study: Additive Main effect and Multiplicative Interaction (AMMI), Genotype and Genotype by Environment interaction (GGE) biplot analysis and, Eberhart and Russellmodel revealed that Acc. 203544 is stable high yielding (3.16 ton ha-1) with a yield advantage of 13.7% over the best standard check, Gute (2.78 ton ha-1), and thus should be recommended for possible release with wider environmental adaptability. Acc. 242111 (3.08 ton ha-1), Acc. BKFM0051 (3.07 ton ha-1) and Acc.229738 (2.99 ton ha-1) were also high yielding, but showed narrow stability and thus should be recommended for verification and possible release for specific environments.Key words/phrases: Additive main effect and multiplicative interaction (AMMI), Finger millet (Eleusine coracana subsp. coracana), Genotype by Environment Interaction (GEI

    Rigidly Rotating Strings in Stationary Spacetimes

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    In this paper we study the motion of a rigidly rotating Nambu-Goto test string in a stationary axisymmetric background spacetime. As special examples we consider the rigid rotation of strings in flat spacetime, where explicit analytic solutions can be obtained, and in the Kerr spacetime where we find an interesting new family of test string solutions. We present a detailed classification of these solutions in the Kerr background.Comment: 19 pages, Latex, 9 figures, revised for publication in Classical and Quantum Gravit

    Thick domain walls around a black hole

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    We discuss the gravitationally interacting system of a thick domain wall and a black hole. We numerically solve the scalar field equation in the Schwarzschild spacetime and obtain a sequence of static axi-symmetric solutions representing thick domain walls. We find that, for the walls near the horizon, the Nambu--Goto approximation is no longer valid.Comment: 18 pages, 11 figures, one reference adde

    Inhibiting the Thermal Gelation of Copolymer Stabilized Nonaqueous Dispersions and the Synthesis of Full Color PMMA Particles

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    Polymeric particle dispersions have numerous potential applications; currently one of the most relevant is their use as inks in electrophoretic displays. These colloidal particles are synthesized from the appropriate monomer using nonaqueous dispersion (NAD) polymerization in a nonpolar solvent, which requires a stabilizer to control particle size and morphology. We have previously reported the facile synthesis of poly(methyl methacrylate)-block-poly(octadecyl acrylate) (PMMA-b-PODA) by atom transfer radical polymerization (ATRP), and its use in the NAD polymerization of MMA in hexane/dodecane solvent mixtures. Here we report the synthesis of monodisperse PMMA particles in dodecane following a standard “industrial” procedure using these PMMA-b-PODA stabilizers. However, it was observed that the particle suspensions solidified when they were left at temperatures below ?18 °C yet redispersed upon being heated. Differential scanning calorimetry, dynamic light scattering, and rheological studies demonstrated that this thermoresponsive behavior was due to a liquid–gel transition occurring at 17.5 °C as a consequence of the upper critical solution temperature of PODA in dodecane being traversed. Consequently, new copolymers were synthesized by ATRP with an ethylhexyl acrylate (EHA) co-monomer incorporated into the lyophilic (dodecane compatible) block. Dispersions stabilized by these PMMA-b-P(ODA-co-EHA) polymers with high EHA contents exhibited lower gelation temperatures because of the greater solvent compatibility with dodecane. The use of a PMMA65-b-(ODA10-co-EHA45) copolymer stabilizer (with the highest EHA content) gave PMMA dispersions that showed no gelation down to 4 °C and monodisperse cross-linked PMMA particles containing organic dyes (cyan, magenta, red, and black) giving colored particles across the size range of approximately 100–1300 nm

    The trends and future of biotechnology crops for insect pest control

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    Biotech crops, including those that are genetically modified (GM) with Bacillus thuringiensis (Bt) endotoxins for insect resistance, have been cultivated commercially and adopted in steadily increasing numbers of countries over the past 14 years. This review discusses the current status of insect resistant transgenic crops and the often raised concern that its resilience is limited and that its efficacy will be compromised by insect resistance. We consider this trait as it is currently deployed in fields across the world as well as potential candidates that are at various stages of development along the pathway between the laboratory and deregulation. Future trends and prospects for biotechnological applications to mediate crop protection against insects are also considered. These include strategies employing stacked genes, modified Bt toxins, vegetative insecticidal proteins, lectins, endogenous resistance mechanisms as well as novel approaches. In addition, the benefits and risks associated with the adoption of GM insect resistant crops, especially for developing countries and resource-poor smallholder farmers are also discussed

    Thick Domain Walls and Charged Dilaton Black Holes

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    We study a black hole domain wall system in dilaton gravity which is the low-energy limit of the superstring theory. We solve numerically equations of motion for real self-interacting scalar field and justify the existence of static axisymmetric field configuration representing the thick domain wall in the background of a charged dilaton black hole. It was also confirmed that the extreme dilaton black hole always expelled the domain wall.Comment: 10 pages, 8 figures; to be published in Phys. Rev. D1
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