32 research outputs found

    Cumulative acquisition of pathogenicity islands has shaped virulence potential and contributed to the emergence of LEE-negative Shiga toxinproducing Escherichia coli strains

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    Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens causing severe gastroenteritis, which may lead to hemolytic uremic syndrome. The Locus of Enterocyte Effacement (LEE), a Pathogenicity Island (PAI), is a major determinant of intestinal epithelium attachment of a group of STEC strains; however, the virulence repertoire of STEC strains lacking LEE, has not been fully characterized. The incidence of LEE-negative STEC strains has increased in several countries, highlighting the relevance of their study. In order to gain insights into the basis for the emergence of LEE-negative STEC strains, we performed a large-scale genomic analysis of 367 strains isolated worldwide from humans, animals, food and the environment. We identified uncharacterized genomic islands, including two PAIs and one Integrative Conjugative Element. Additionally, the Locus of Adhesion and Autoaggregation (LAA) was the most prevalent PAI among LEE-negative strains and we found that it contributes to colonization of the mice intestine. Our comprehensive and rigorous comparative genomic and phylogenetic analyses suggest that the accumulative acquisition of PAIs has played an important, but currently unappreciated role, in the evolution of virulence in these strains. This study provides new knowledge on the pathogenicity of LEE-negative STEC strains and identifies molecular markers for their epidemiological surveillance.This study was supported by FONDECYT grant 1161161 to R. Vidal and CONICYT-PCHA/2014-63140238 fellowship to D. Montero. Work at USC-LREC was supported by Project PI16/01477 from Plan Estatal de I+D+I 2013-2016, Instituto de Salud Carlos III, Subdirección General de Evaluación y Fomento de la Investigación and FEDER, Ministerio de Economia, Industria y Competitividad, Gobierno de España and Project ED431C 2017/57 from the Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia and FEDER. Fondecyt 11150966 to Felipe Del Canto. Consejo Nacional de Ciencia y Tecnología; [Fondo Nacional de Desarrollo Científico y Tecnológico].S

    25th annual computational neuroscience meeting: CNS-2016

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    The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

    Samverkan mellan forskare och bibliotek : Mot en förändrad syn på publiceringsstrategier

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    Universitets- och högskolebiblioteken har i allt större utsträckning fått en viktig roll att spela i spridandet av det egna lärosätets forskning. Detta ger utrymme för samarbete mellan bibliotek och forskare: biblioteket behöver kunskap om de faktorer som styr hur forskarna väljer att sprida sina resultat, för att i sin tur kunna ge forskarna stöd i valet av publiceringskanaler och publiceringsstrategier. I detta paper undersöker vi attityder och strategier hos fyra forskare med anknytning till Kungliga Tekniska högskolans bibliotek, samt föreslår möjliga vägar till samverkan mellan bibliotek och forskare.QC 20150116</p

    Samverkan mellan forskare och bibliotek : Mot en förändrad syn på publiceringsstrategier

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    Universitets- och högskolebiblioteken har i allt större utsträckning fått en viktig roll att spela i spridandet av det egna lärosätets forskning. Detta ger utrymme för samarbete mellan bibliotek och forskare: biblioteket behöver kunskap om de faktorer som styr hur forskarna väljer att sprida sina resultat, för att i sin tur kunna ge forskarna stöd i valet av publiceringskanaler och publiceringsstrategier. I detta paper undersöker vi attityder och strategier hos fyra forskare med anknytning till Kungliga Tekniska högskolans bibliotek, samt föreslår möjliga vägar till samverkan mellan bibliotek och forskare.QC 20150116</p

    Planning for Serendipity

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    Abstract-Recently there has been a lot of focus on human robot co-habitation issues that are often orthogonal to many aspects of human-robot teaming; e.g. on producing socially acceptable behaviors of robots and de-conflicting plans of robots and humans in shared environments. However, an interesting offshoot of these settings that has largely been overlooked is the problem of planning for serendipity -i.e. planning for stigmergic collaboration without explicit commitments on agents in co-habitation. In this paper we formalize this notion of planning for serendipity for the first time, and provide an Integer Programming based solution for this problem. Further, we illustrate the different modes of this planning technique on a typical Urban Search and Rescue scenario and show a reallife implementation of the ideas on the Nao Robot interacting with a human colleague
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