923 research outputs found

    The COOH terminus of the c-Abl tyrosine kinase contains distinct F- and G-actin binding domains with bundling activity

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    The myristoylated form of c-Abl protein, as well as the P210bcr/abl protein, have been shown by indirect immunofluorescence to associate with F-actin stress fibers in fibroblasts. Analysis of deletion mutants of c-Abl stably expressed in fibroblasts maps the domain responsible for this interaction to the extreme COOH-terminus of Abl. This domain mediates the association of a heterologous protein with F-actin filaments after microinjection into NIH 3T3 cells, and directly binds to F-actin in a cosedimentation assay. Microinjection and cosedimentation assays localize the actin-binding domain to a 58 amino acid region, including a charged motif at the extreme COOH-terminus that is important for efficient binding. F-actin binding by Abl is calcium independent, and Abl competes with gelsolin for binding to F- actin. In addition to the F-actin binding domain, the COOH-terminus of Abl contains a proline-rich region that mediates binding and sequestration of G-actin, and the Abl F- and G-actin binding domains cooperate to bundle F-actin filaments in vitro. The COOH terminus of Abl thus confers several novel localizing functions upon the protein, including actin binding, nuclear localization, and DNA binding. Abl may modify and receive signals from the F-actin cytoskeleton in vivo, and is an ideal candidate to mediate signal transduction from the cell surface and cytoskeleton to the nucleus

    Exploring how harming and helping behaviors drive prediction and explanation during anthropomorphism

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    Cacioppo and colleagues advanced the study of anthropomorphism by positing three motives that moderated the occurrence of this phenomenon; belonging, effectance, and explanation. Here, we further this literature by exploring the extent to which the valence of a target’s behavior influences its anthropomorphism when perceivers attempt to explain and predict that target’s behavior, and the involvement of brain regions associated with explanation and prediction in such anthropomorphism. Participants viewed videos of varying visually complex agents - geometric shapes, computer generated (CG) faces, and greebles - in nonrandom motion performing harming and helping behaviors. Across two studies, participants reported a narrative that explained the observed behavior (both studies) while we recorded brain activity (study one), and participants predicted future behavior of the protagonist shapes (study two). Brain regions implicated in prediction error (striatum), not language generation (inferior frontal gyrus; IFG) engaged more to harming than helping behaviors during the anthropomorphism of such stimuli. Behaviorally, we found greater anthropomorphism in explanations of harming rather than helping behaviors, but the opposite pattern when participants predicted the agents’ behavior. Together, these studies build upon the anthropomorphism literature by exploring how the valence of behavior drives explanation and prediction

    How can the Data Revolution contribute to climate action in smallholder agriculture?

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    In this article, we discuss the ongoing Data Revolution in relation to climate action in agriculture. Data are highly relevant for climate action, as climate change makes current local knowledge increasingly irrelevant and requires smarter management of agricultural systems. We discuss five datarelated concepts and explore how they are linked with agricultural climate action: lean data, crowdsourcing, big data, ubiquitous computing, and information design. We show practical examples for each of these concepts. There are many opportunities for improving agricultural development projects, providing new services to smallholder farmers, and generating better information for policy- and decision-making. Making the Data Revolution work for smallholder farmers’ climate action not only takes further technological development, but also requires careful governance and public investment to avoid a few actors taking over the current innovation space and stifle further development

    Design of a ring resonator-based optical beam forming network for phased array receive antennas

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    A novel squint-free ring resonator-based optical beam forming network (OBFN) for phased array antennas (PAA) is proposed. It is intended to provide broadband connectivity to airborne platforms via geostationary satellites. In this paper, we present the design of the OBFN and its control system. Our goal is to deliver large bandwidth Ku-band connectivity between antennas, mount conformal to the airplane fuselage and on a geostationary satellite, respectively.This way it would be possible to bring live DVB-S television to airplane passengers. In this paper, we present recent research conducted on a 4 × 1 ring resonator-based OBFN test set-up. This OBFN has four optical input ports and one optical output port. It is tuned to provide the desired signal combination with optimal constructive interference between the modulated input signals from the PAA. Therefore, combining circuitry and delay elements are required. The OBFN is tuned by electrically heating tunable true time delay (TTD) elements. These are built using optical ring resonators (ORRs). By cascading multiple ORRs with different resonance frequencies, it is possible to create a TTD with a large bandwidth. Optical beam forming is used because it provides advantages over traditional beam forming methods. These advantages are: large bandwidth, EMI resistance, and, when integrated onto a single chip, compactness and low costs. The OBFN is created using planar optical waveguide technology and consists of the following building blocks: waveguides, Mach-Zehnder interferometers, (MZIs) couplers and ORRs. The tuning of the OBFN is done by an electronic control system using a microcontroller. Communication with a PC is possible using USB. To our knowledge, this is the first integrated ORR-based OBFN circuit for PAA satellite reception

    Molecular and Genetic Evidence for a Virus-Encoded Glycosyltransferase Involved in Protein Glycosylation

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    AbstractThe major capsid protein, Vp54, of chlorella virus PBCV-1 is a glycoprotein that contains either one glycan of ∼30 sugar residues or two similar glycans of ∼15 residues. Previous analysis of PBCV-1 antigenic mutants that contained altered Vp54 glycans led to the conclusion that unlike other glycoprotein-containing viruses, most, if not all, of the enzymes involved in the synthesis of the Vp54 glycan are probably encoded by PBCV-1 (I.-N. Wang et al., 1993, Proc. Natl. Acad. Sci. USA 90, 3840–3844). In this report we used molecular and genetic approaches to begin to identify these virus genes. Comparing the deduced amino acid sequences of the putative 375 PBCV-1 protein-encoding genes to databases identified seven potential glycosyltransferases. One gene, designated a64r, encodes a 638-amino-acid protein that has four motifs conserved in “Fringe type” glycosyltransferases. Analysis of 13 PBCV-1 antigenic mutants revealed mutations in a64r that correlated with a specific antigenic variation. Dual-infection experiments with different antigenic mutants indicated that viruses that contained wild-type a64r could complement and recombine with viruses that contained mutant a64r to form wild-type virus. Therefore, we conclude that a64r encodes a glycosyltransferase involved in synthesizing the Vp54 glycan. This is the first report of a virus-encoded glycosyltransferase involved in protein glycosylation

    Using local rural knowledge to enhance STEM learning for gifted and talented students in Australia

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    In order to supply a future Science, Technology, Engineering, and Mathematics (STEM) workforce, Australia needs to engage its most capable and gifted secondary students in quality STEM learning, either within school or through extra-curricular opportunities, so that they will continue into STEM-based tertiary degrees. High-achieving students in rural communities may face additional barriers to STEM learning that can limit their ability to pursue advanced STEM studies and occupations. This small-scale research project sought to explore a group of gifted lower secondary students’ engagement and experiences in a STEM programme designed around a local rural knowledge model as reported by Avery (2013), which uses local knowledge as a vehicle for science learning. This multi-method study was conducted with 26 students years 7 and 8 in a rural school. Information about students’ general science class experiences were collected quantitatively. These experiences contrasted the local rural knowledge programme, where the students worked with an ecologist and experienced science educators to rehabilitate small plots of damaged land close to the school site. Qualitative data were collected throughout the programme to determine its influence on students’ engagement and learning in STEM. The research found that the local rural knowledge model enhanced students’ engagement in STEM learning and they felt that they retained knowledge better as a result of the authentic learning experience. Students also engaged the wider community in the process, leading to broader translation of the STEM learning

    Gene Gangs of the Chloroviruses: Conserved Clusters of Collinear Monocistronic Genes

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    Chloroviruses (family Phycodnaviridae) are dsDNA viruses found throughout the world’s inland waters. The open reading frames in the genomes of 41 sequenced chloroviruses (330 + 40 kbp each) representing three virus types were analyzed for evidence of evolutionarily conserved local genomic “contexts”, the organization of biological information into units of a scale larger than a gene. Despite a general loss of synteny between virus types, we informatically detected a highly conserved genomic context defined by groups of three or more genes that we have termed “gene gangs”. Unlike previously described local genomic contexts, the definition of gene gangs requires only that member genes be consistently co-localized and are not constrained by strand, regulatory sites, or intervening sequences (and therefore represent a new type of conserved structural genomic element). An analysis of functional annotations and transcriptomic data suggests that some of the gene gangs may organize genes involved in specific biochemical processes, but that this organization does not involve their coordinated expression

    Catalysis of Chlorovirus Production by the Foraging of \u3ci\u3eBursaria truncatella\u3c/i\u3e on \u3ci\u3eParamecia bursaria\u3c/i\u3e Containing Endosymbiotic Algae

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    Chloroviruses are large viruses that replicate in chlorella-like green algae and normally exist as mutualistic endosymbionts (referred to as zoochlorellae) in protists such as Paramecium bursaria. Chlorovirus populations rise and fall in indigenous waters through time; however, the factors involved in these virus fluctuations are still under investigation. Chloroviruses attach to the surface of P. bursaria but cannot infect their zoochlorellae hosts because the viruses cannot reach the zoochlorellae as long as they are in the symbiotic phase. Predators of P. bursaria, such as copepods and didinia, can bring chloroviruses into contact with zoochlorellae by disrupting the paramecia, which results in an increase in virus titers in microcosm experiments. Here, we report that another predator of P. bursaria, Bursaria truncatella, can also increase chlorovirus titers. After two days of foraging on P. bursaria, B. truncatella increased infectious chlorovirus abundance about 20 times above the controls. Shorter term foraging (3 h) resulted in a small increase of chlorovirus titers over the controls and more foraging generated more chloroviruses. Considering that B. truncatella does not release viable zoochlorellae either during foraging or through fecal pellets, where zoochlorellae could be infected by chlorovirus, we suggest a third pathway of predator virus catalysis. By engulfing the entire protist and digesting it slowly, virus replication can occur within the predator and some of the virus is passed out through a waste vacuole. These results provide additional support for the hypothesis that predators of P. bursaria are important drivers of chlorovirus population sizes and dynamics

    The Rural Household Multi-Indicator Survey (RHoMIS): A rapid, cost-effective and flexible tool for farm household characterisation, targeting interventions and monitoring progress towards climate-smart agriculture

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    RHoMIS is a rapid, cheap, digital farm household-level survey and analytical engine for characterizing, targeting and monitoring agricultural performance. RHoMIS captures information describing farm productivity and practices, nutrition, food security, gender equity, climate and poverty. RHoMIS is action-ready, tested and adapted for diverse systems in more than 7,000 households across the global tropics. Want more info? See: http://rhomis.net
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