447 research outputs found

    Modelling and experimental investigation of carangiform locomotion for control

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    We propose a model for planar carangiform swimming based on conservative equations for the interaction of a rigid body and an incompressible fluid. We account for the generation of thrust due to vortex shedding through controlled coupling terms. We investigate the correct form of this coupling experimentally with a robotic propulsor, comparing its observed behavior to that predicted by unsteady hydrodynamics. Our analysis of thrust generation by an oscillating hydrofoil allows us to characterize and evaluate certain families of gaits. Our final swimming model takes the form of a control-affine nonlinear system

    In vivo blockade of pemphigus vulgaris acantholysis by inhibition of intracellular signal transduction cascades

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    BACKGROUND: Pemphigus vulgaris (PV) is an autoimmune disease characterized by mucocutaneous intraepithelial blisters and pathogenic autoantibodies against desmoglein 3. The mechanism of blister formation in pemphigus has not been defined; however, in vitro data suggest a role for activation of intracellular signalling cascades. OBJECTIVES: To investigate the contribution of these signalling pathways to the mechanism of PV IgG-induced acantholysis in vivo. METHODS: We used the passive transfer mouse model. Mice were injected with IgG fractions of sera from a patient with PV, with or without pretreatment with inhibitors of proteins that mediate intracellular signalling cascades. RESULTS: Inhibitors of tyrosine kinases, phospholipase C, calmodulin and the serine/threonine kinase protein kinase C prevented PV IgG-induced acantholysis in vivo. CONCLUSIONS: These observations strongly support the role of intracellular signalling cascades in the molecular mechanism of PV IgG-induced acantholysis

    Characterisation of Perennial Ryegrass Parental Inbred Lines for Generating Recombinant Inbred Lines for Fine Mapping and Gene Cloning

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    Intermated recombinant inbred lines (IRIs) are a powerful tool for fine mapping and cloning of genes. Such population structures have been particularly helpful for cloning of genes in the model genetic plant Arabidopsis thaliana. IRIs or recombinant inbred lines (RILs) would be valuable for perennial ryegrass (Lolium perenne), but its allogamous character means that the construction of RILs is a difficult task. The international Lolium community would benefit from the development of such lines. The aims of the projects are to characterise the parental lines and initial generations at the (1) phenotypic, (2) molecular and (3) molecular cytogenetic level

    Effectiveness of a Simulated Pack to Manipulate Wolf Movements

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    Bioboundaries, also called biofences, are deterrents that attempt to exploit certain innate behaviors to exclude wildlife from target areas. We hypothesized that human-deployed scent marks and playbacks of foreign howls could simulate a territorial gray wolf (Canis lupus) pack impinging on a resident pack, thereby causing the resident pack to move. During summer 2010, we deployed a simulated-pack bioboundary near 3 wolf packs in northern Wisconsin and monitored their movements relative to 3 wolf packs experiencing a sham treatment, to control for effects of human presence. We analyzed wolves’ locations (≥1 location per week) and used linear models with mixed effects to examine distance from the rendezvous site as a function of treatment (sham or experimental) and phase of treatment (before or after treatment was initiated), while accounting for variations in individual wolves. We found little evidence that biofences, as configured and deployed in this study, caused wolves to change use of their territory

    Autoimmune and infectious skin diseases that target desmogleins

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    Desmosomes are intercellular adhesive junctions of epithelial cells that contain two major transmembrane components, the desmogleins (Dsg) and desmocollins (Dsc), which are cadherin-type cell–cell adhesion molecules and are anchored to intermediate filaments of keratin through interactions with plakoglobin and desmoplakin. Desmosomes play an important role in maintaining the proper structure and barrier function of the epidermis and mucous epithelia. Four Dsg isoforms have been identified to date, Dsg1–Dsg4, and are involved in several skin and heart diseases. Dsg1 and Dsg3 are the two major Dsg isoforms in the skin and mucous membranes, and are targeted by IgG autoantibodies in pemphigus, an autoimmune disease of the skin and mucous membranes. Dsg1 is also targeted by exfoliative toxin (ET) released by Staphylococcus aureus in the infectious skin diseases bullous impetigo and staphylococcal scalded skin syndrome (SSSS). ET is a unique serine protease that shows lock and key specificity to Dsg1. Dsg2 is expressed in all tissues possessing desmosomes, including simple epithelia and myocardia, and mutations in this gene are responsible for arrhythmogenic right ventricular cardiomyopathy/dysplasia. Dsg4 plays an important adhesive role mainly in hair follicles, and Dsg4 mutations cause abnormal hair development. Recently, an active disease model for pemphigus was generated by a unique approach using autoantigen-deficient mice that do not acquire tolerance against the defective autoantigen. Adoptive transfer of Dsg3−/− lymphocytes into mice expressing Dsg3 induces stable anti-Dsg3 IgG production with development of the pemphigus phenotype. This mouse model is a valuable tool with which to investigate immunological mechanisms of harmful IgG autoantibody production in pemphigus. Further investigation of desmoglein molecules will continue to provide insight into the unsolved pathophysiological mechanisms of diseases and aid in the development of novel therapeutic strategies with minimal side effects

    Laminin-6 and Laminin-5 Are Recognized by Autoantibodies in a Subset of Cicatricial Pemphigoid

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    We characterized basement membrane zone (BMZ) autoantigens targeted by autoantibodies (AAb) from patients with cicatricial pemphigoid. Serum from a patient with severe oral cicatricial pemphigoid contained IgG anti-BMZ AAb. The AAb labeled a lower BMZ component on salt-split skin and localized to the lower lamina lucida/lamina densa by direct and indirect immunoelectron microscopy (HEM) but did not label blood vessels. The AAb did not react with EHS laminin-1 and type IV collagen, pepsinized human type IV collagen, recombinant entactin, or NC1 domain of type VII collagen by dot blotting and western blotting. We focused our studies on the laminin family, as laminin-5 was identified as an autoantigen in cicatricial pemphigoid. Culture-conditioned media from normal keratinocytes (containing laminin-6 and laminin-5) and JEB keratinocytes (containing laminin-6 but not laminin-5) were studied by western blotting. Under nonreducing conditions, the patient's AAb recognized a 600-kDa protein (laminin-6) intensely and a 400-kDa protein (laminin-5) weakly in normal keratinocyte medium even though abundant laminin-5 was present. In JEB keratinocyte medium, however, the 600-kDa protein (laminin-6) alone was recognized by the patient's AAb. The AAb also immunolabeled BMZ of JEB skin that lacked laminin-5. The AAb from this patient and two other patients with anti-laminin-5 cicatricial pemphigoid immunoprecipitated both laminin-6 an4 laminin-5. Taken together, the results of IEM, non-reducing western blotting, immunoprecipitation, and JEB skin BMZ immunolabeling indicate that laminin-6, as well as laminin-5, is identified by the AAb from a subset of cicatricial pemphigoid patients. We propose the name “anti-laminin cicatricial pemphigoid” for this subset

    S-SAP molecular marker-based detection of interspecific variability among grape cultivars

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    Genetska unutarsortna varijabilnost temelji se na pretpostavci da tijekom vremena dolazi do pojave spontanih mutacija u genomu sorte koje zbog vegetativnog načina razmnožavanja ostaju fiksirane. Svaka informacija o unutarsortnoj varijabilnosti može biti od velike važnosti prije odluke o tome koje trsove zadržati nakon provjere zdravstvenog statusa te može pružiti uvid u homogenost populacije i potencijal klonske selekcije. U ovom istraživanju korišten je sustav markera temeljen na retrotranspozonima – modificirana S-SAP metoda koja je u prijašnjim istraživanjima pokazala potencijal za razlikovanje klonova. Korišten biljni materijal vinove loze sastojao se od 22 primke dviju različitih sorti: Zlatarice blatske bijele i Glavinuše. S-SAP metoda provedena je sa 6 različitih kombinacija početnica. Ovom metodom uspješno su razlikovane obje sorte, a detektirane su i razlike među pojedinim jedinkama. Stupanj polimorfizma, iako analize nisu rađene na certificiranom klonskom materijalu, u skladu je sa sličnim istraživanjima rađenim na certificiranom materijalu. Početnica F100 je detektirala najviše razlika i može se preporučiti u daljnjim istraživanjima. Dobiveni rezultati pružaju smjernice prilikom daljnje propagacije i revitalizacije.Intra-varietal variability is based on the assumption that during the time spontaneous mutations occur in the varieties genome and stay fixed because of vegetative propagation. Any kind of information about intra-varietal variability could be of importance before making a decision which vines to keep after verification of their health status and could provide an insight into homogeneity of the population and into the potential of the clonal selection. In this study a retrotransposon based marker system was used – a modified SSAP method which, in previous studies, showed the potential for differentiating clones. Collected grapevine plant material consisted of 22 accessions representing two Croatian varieties: Zlatarica blatska bijela and Glavinuša. S-SAP method was performed using 6 different primer combinations. This method successfully differentiated both varieties and also detected some clonal differences among tested accessions. Although the analyses were not done on certified clonal material, level of polymorphism was similar to those in similar studies using certified clones. The use of universal retrotransposon primer F100 resulted in most observed polymorphism. Obtained results provide guidelines for further propagation and revitalization

    S-SAP molecular marker-based detection of interspecific variability among grape cultivars

    Get PDF
    Genetska unutarsortna varijabilnost temelji se na pretpostavci da tijekom vremena dolazi do pojave spontanih mutacija u genomu sorte koje zbog vegetativnog načina razmnožavanja ostaju fiksirane. Svaka informacija o unutarsortnoj varijabilnosti može biti od velike važnosti prije odluke o tome koje trsove zadržati nakon provjere zdravstvenog statusa te može pružiti uvid u homogenost populacije i potencijal klonske selekcije. U ovom istraživanju korišten je sustav markera temeljen na retrotranspozonima – modificirana S-SAP metoda koja je u prijašnjim istraživanjima pokazala potencijal za razlikovanje klonova. Korišten biljni materijal vinove loze sastojao se od 22 primke dviju različitih sorti: Zlatarice blatske bijele i Glavinuše. S-SAP metoda provedena je sa 6 različitih kombinacija početnica. Ovom metodom uspješno su razlikovane obje sorte, a detektirane su i razlike među pojedinim jedinkama. Stupanj polimorfizma, iako analize nisu rađene na certificiranom klonskom materijalu, u skladu je sa sličnim istraživanjima rađenim na certificiranom materijalu. Početnica F100 je detektirala najviše razlika i može se preporučiti u daljnjim istraživanjima. Dobiveni rezultati pružaju smjernice prilikom daljnje propagacije i revitalizacije.Intra-varietal variability is based on the assumption that during the time spontaneous mutations occur in the varieties genome and stay fixed because of vegetative propagation. Any kind of information about intra-varietal variability could be of importance before making a decision which vines to keep after verification of their health status and could provide an insight into homogeneity of the population and into the potential of the clonal selection. In this study a retrotransposon based marker system was used – a modified SSAP method which, in previous studies, showed the potential for differentiating clones. Collected grapevine plant material consisted of 22 accessions representing two Croatian varieties: Zlatarica blatska bijela and Glavinuša. S-SAP method was performed using 6 different primer combinations. This method successfully differentiated both varieties and also detected some clonal differences among tested accessions. Although the analyses were not done on certified clonal material, level of polymorphism was similar to those in similar studies using certified clones. The use of universal retrotransposon primer F100 resulted in most observed polymorphism. Obtained results provide guidelines for further propagation and revitalization
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