30 research outputs found

    Rapid Chromosome Evolution in Recently Formed Polyploids in Tragopogon (Asteraceae)

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    Polyploidy, frequently termed "whole genome duplication", is a major force in the evolution of many eukaryotes. Indeed, most angiosperm species have undergone at least one round of polyploidy in their evolutionary history. Despite enormous progress in our understanding of many aspects of polyploidy, we essentially have no information about the role of chromosome divergence in the establishment of young polyploid populations. Here we investigate synthetic lines and natural populations of two recently and recurrently formed allotetraploids Tragopogon mirus and T. miscellus (formed within the past 80 years) to assess the role of aberrant meiosis in generating chromosomal/genomic diversity. That diversity is likely important in the formation, establishment and survival of polyploid populations and species.Applications of fluorescence in situ hybridisation (FISH) to natural populations of T. mirus and T. miscellus suggest that chromosomal rearrangements and other chromosomal changes are common in both allotetraploids. We detected extensive chromosomal polymorphism between individuals and populations, including (i) plants monosomic and trisomic for particular chromosomes (perhaps indicating compensatory trisomy), (ii) intergenomic translocations and (iii) variable sizes and expression patterns of individual ribosomal DNA (rDNA) loci. We even observed karyotypic variation among sibling plants. Significantly, translocations, chromosome loss, and meiotic irregularities, including quadrivalent formation, were observed in synthetic (S(0) and S(1) generations) polyploid lines. Our results not only provide a mechanism for chromosomal variation in natural populations, but also indicate that chromosomal changes occur rapidly following polyploidisation.These data shed new light on previous analyses of genome and transcriptome structures in de novo and establishing polyploid species. Crucially our results highlight the necessity of studying karyotypes in young (<150 years old) polyploid species and synthetic polyploids that resemble natural species. The data also provide insight into the mechanisms that perturb inheritance patterns of genetic markers in synthetic polyploids and populations of young natural polyploid species

    TYK2 Kinase Activity Is Required for Functional Type I Interferon Responses In Vivo

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    Tyrosine kinase 2 (TYK2) is a member of the Janus kinase (JAK) family and is involved in cytokine signalling. In vitro analyses suggest that TYK2 also has kinase-independent, i.e., non-canonical, functions. We have generated gene-targeted mice harbouring a mutation in the ATP-binding pocket of the kinase domain. The Tyk2 kinase-inactive (Tyk2K923E) mice are viable and show no gross abnormalities. We show that kinase-active TYK2 is required for full-fledged type I interferon- (IFN) induced activation of the transcription factors STAT1-4 and for the in vivo antiviral defence against viruses primarily controlled through type I IFN actions. In addition, TYK2 kinase activity was found to be required for the protein’s stability. An inhibitory function was only observed upon over-expression of TYK2K923E in vitro. Tyk2K923E mice represent the first model for studying the kinase-independent function of a JAK in vivo and for assessing the consequences of side effects of JAK inhibitors

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    Opinnäytetyössäni käsittelen omaa taiteellista tuotantoani. Aluksi kerron kuinka olen päätynyt tekemään sitä mitä teen ja esittelen kuvasarjani. Tämän jälkeen käyn läpi käsitteitä, jotka liittyvät työhöni. Oma työskentelyni on kehittynyt kohti valon kuvaamista. Kuvaan valoa tietyn ajan kuluessa tai aikaa tietyssä valossa. Miten päin asiaa haluaakaan ajatella. Tutkin valon luonteita vuorokauden- ja vuodenaikojen muutoksina. Kuinka erilainen valo on eri aikoina? Miten se muuttaa kohdettaan? Ja kuinka se suhteutuu ympäristön väreihin? Tekstissäni perehdyn valoon Claude Monetin kautta. Kävelyllä on ollut tärkeä merkitys teosteni synnylle. Se toimii inspiraation lähteenä ja oli merkittävässä roolissa ensimmäisissä sarjoissani. Käsittelen kävelyn teemaa Richard Longin työskentelyn avulla. Aika, vuodenajat, toisto ja sattuma, sekä valokuvauksen ja maalauksen suhde ovat aiheina seuraavissa luvuissa. Käyn näitä asioita läpi taiteilijoiden avulla, joiden teoksiin ja työskentelyyn olen tutustunut kirjoittaessani tätä lopputyötä. Yhteistä kaikille valitsemilleni taiteilijoille tai teoksille on pitkien ajanjaksojen käyttäminen. Muita yhdistäviä tekijöitä ovat työskentelymetodit, tekniikka tai visuaalinen lopputulos

    Achado incidental de agenesia do lobo hepático esquerdo em paciente com colecistite aguda Incidental finding of agenesis of the left hepatic lobe in a patient with acute cholecystitis

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    INTRODUÇÃO: Anomalias da morfologia hepática são entidades raras causadas por desenvolvimento embriológico anormal do fígado. Podem ser classificadas como anomalias devido a desenvolvimento defeituoso do fígado (agenesia, aplasia e hipoplasia) ou devido ao desenvolvimento excessivo (lobos acessórios). RELATO DO CASO: Paciente de 48 anos, do sexo feminino, obesa (IMC=40), que procurou o serviço de emergência com quadro de colecistite aguda. A paciente foi submetida a colecistectomia videolaparoscópica e durante o procedimento cirúrgico foi verificada a agenesia do lobo hepático esquerdo. A vesícula biliar estava em sua topografia habitual e não havia parênquima hepático à esquerda do ligamento falciforme. A colecistectomia foi realizada sem intercorrências e uma banda gástrica foi colocada para o tratamento da obesidade mórbida. Ela recebeu alta após 60 horas<br>INTRODUCTION: Anomalies of hepatic morphology are rare entities caused by abnormal embryological development of the liver. They can be classified as anomalies due to defective development (agenesis, aplasia or hypoplasia) or anomalies due to excessive development of the liver (accessory lobes). CASE REPORT: A 48 years old obese female looked for emergency assistance with acute cholecystitis. An incidental finding of left hepatic lobe agenesis was observed when the patient was submitted to laparoscopic cholecystectomy. There was no hepatic parenchyma to the left of falciform ligament and gallbladder was settled on its normal position. Cholecystectomy was performed uneventfully and an adjustable gastric band was placed for the treatment of the morbid obesity. The patient was discharged after 60 hours
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