6,336 research outputs found

    Mycobacterial infection-induced miR-206 inhibits protective neutrophil recruitment via the CXCL12/CXCR4 signalling axis

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    Pathogenic mycobacteria actively dysregulate protective host immune signalling pathways during infection to drive the formation of permissive granuloma microenvironments. Dynamic regulation of host microRNA (miRNA) expression is a conserved feature of mycobacterial infections across host-pathogen pairings. Here we examine the role of miR-206 in the zebrafish model of Mycobacterium marinum infection, which allows investigation of the early stages of granuloma formation. We find miR-206 is upregulated following infection by pathogenic M. marinum and that antagomir-mediated knockdown of miR-206 is protective against infection. We observed striking upregulation of cxcl12a and cxcr4b in infected miR-206 knockdown zebrafish embryos and live imaging revealed enhanced recruitment of neutrophils to sites of infection. We used CRISPR/Cas9-mediated knockdown of cxcl12a and cxcr4b expression and AMD3100 inhibition of Cxcr4 to show that the enhanced neutrophil response and reduced bacterial burden caused by miR-206 knockdown was dependent on the Cxcl12/Cxcr4 signalling axis. Together, our data illustrate a pathway through which pathogenic mycobacteria induce host miR-206 expression to suppress Cxcl12/Cxcr4 signalling and prevent protective neutrophil recruitment to granulomas

    Patients' perception regarding the influence of individual and social vulnerabilities on the adherence to tuberculosis treatment: a qualitative study

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    Background: Tuberculosis remains an important disease which mainly affects the majority of vulnerable individuals in society, who are subjected to poor living conditions and difficulties to access the services of public health. Under these circumstances, the present study aims to understand patients' perception in relation to the influence of individual and social vulnerabilities on the adherence to tuberculosis treatment. Methods: A qualitative descriptive cross sectional study was conducted in one large municipality at the state of Paraiba, Northeast of Brazil. The study subjects, who were residents of the study site, covered all tuberculosis cases diagnosed between March and June 2015. The sample was defined by the criteria of response saturation. All interviews were audio recorded, and data analysis was developed through the hermeneutic dialectic method and the theory of Generative Route Sense. The project was approved by the Research Ethics Committee of the University of Sao Paulo (USP). Results: A total of 13 individuals were interviewed and the responses were identified into two analytical categories: the difficulties they had and the enabling factors they could mention during their tuberculosis treatment. Patients brought up social exclusion as an obstacle to treatment adherence, which, along with stigmatization, weakened their link with family members and health professionals. Moreover, economic precariousness was a major hindrance to the maintenance of a proper diet and transportation access to health centers. However, social support and directly observed treatment helped to break down barriers of prejudice and to promote individual and family empowerment. Finally, patients also reported that their will to live and faith gave them the strength to continue with the treatment. Conclusions: According to patients in this study, social support and the strengthening of links with family members and health professionals may reduce social exclusion and other difficulties they face, thus encouraging them to the adhere to tuberculosis treatment.Univ Estadual Paraiba, Campina Grande, Paraiba, BrazilUniv Fed Rio Grande do Norte, Natal, RN, BrazilUniv Sao Paulo, Escola Enfermagem, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Enfermagem, Sao Paulo, BrazilFac Santa Maria, Cajazeiras, Paraiba, BrazilUniv Fed Sao Paulo, Escola Paulista Enfermagem, Sao Paulo, BrazilWeb of Scienc

    Universal finite-size scaling amplitudes in anisotropic scaling

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    Phenomenological scaling arguments suggest the existence of universal amplitudes in the finite-size scaling of certain correlation lengths in strongly anisotropic or dynamical phase transitions. For equilibrium systems, provided that translation invariance and hyperscaling are valid, the Privman-Fisher scaling form of isotropic equilibrium phase transitions is readily generalized. For non-equilibrium systems, universality is shown analytically for directed percolation and is tested numerically in the annihilation-coagulation model and in the pair contact process with diffusion. In these models, for both periodic and free boundary conditions, the universality of the finite-size scaling amplitude of the leading relaxation time is checked. Amplitude universality reveals strong transient effects along the active-inactive transition line in the pair contact process.Comment: 16 pages, Latex, 2 figures, final version, to appear in J. Phys.

    Transcription of toll-like receptors 2, 3, 4 and 9, FoxP3 and Th17 cytokines in a susceptible experimental model of canine Leishmania infantum infection

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    Canine leishmaniosis (CanL) due to Leishmania infantum is a chronic zoonotic systemic disease resulting from complex interactions between protozoa and the canine immune system. Toll-like receptors (TLRs) are essential components of the innate immune system and facilitate the early detection of many infections. However, the role of TLRs in CanL remains unknown and information describing TLR transcription during infection is extremely scarce. The aim of this research project was to investigate the impact of L. infantum infection on canine TLR transcription using a susceptible model. The objectives of this study were to evaluate transcription of TLRs 2, 3, 4 and 9 by means of quantitative reverse transcription polymerase chain reaction (qRT-PCR) in skin, spleen, lymph node and liver in the presence or absence of experimental L. infantum infection in Beagle dogs. These findings were compared with clinical and serological data, parasite densities in infected tissues and transcription of IL-17, IL-22 and FoxP3 in different tissues in non-infected dogs (n = 10), and at six months (n = 24) and 15 months (n = 7) post infection. Results revealed significant down regulation of transcription with disease progression in lymph node samples for TLR3, TLR4, TLR9, IL-17, IL-22 and FoxP3. In spleen samples, significant down regulation of transcription was seen in TLR4 and IL-22 when both infected groups were compared with controls. In liver samples, down regulation of transcription was evident with disease progression for IL-22. In the skin, upregulation was seen only for TLR9 and FoxP3 in the early stages of infection. Subtle changes or down regulation in TLR transcription, Th17 cytokines and FoxP3 are indicative of the silent establishment of infection that Leishmania is renowned for. These observations provide new insights about TLR transcription, Th17 cytokines and Foxp3 in the liver, spleen, lymph node and skin in CanL and highlight possible markers of disease susceptibility in this model

    The emerging structure of the Extended Evolutionary Synthesis: where does Evo-Devo fit in?

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    The Extended Evolutionary Synthesis (EES) debate is gaining ground in contemporary evolutionary biology. In parallel, a number of philosophical standpoints have emerged in an attempt to clarify what exactly is represented by the EES. For Massimo Pigliucci, we are in the wake of the newest instantiation of a persisting Kuhnian paradigm; in contrast, Telmo Pievani has contended that the transition to an EES could be best represented as a progressive reformation of a prior Lakatosian scientific research program, with the extension of its Neo-Darwinian core and the addition of a brand-new protective belt of assumptions and auxiliary hypotheses. Here, we argue that those philosophical vantage points are not the only ways to interpret what current proposals to ‘extend’ the Modern Synthesis-derived ‘standard evolutionary theory’ (SET) entail in terms of theoretical change in evolutionary biology. We specifically propose the image of the emergent EES as a vast network of models and interweaved representations that, instantiated in diverse practices, are connected and related in multiple ways. Under that assumption, the EES could be articulated around a paraconsistent network of evolutionary theories (including some elements of the SET), as well as models, practices and representation systems of contemporary evolutionary biology, with edges and nodes that change their position and centrality as a consequence of the co-construction and stabilization of facts and historical discussions revolving around the epistemic goals of this area of the life sciences. We then critically examine the purported structure of the EES—published by Laland and collaborators in 2015—in light of our own network-based proposal. Finally, we consider which epistemic units of Evo-Devo are present or still missing from the EES, in preparation for further analyses of the topic of explanatory integration in this conceptual framework

    Synthetic Peptides Mimic gp75 from Paracoccidioides brasiliensis in the Diagnosis of Paracoccidioidomycosis

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    Paracoccidioidomycosis (PCM) is a systemic granulomatous disease, endemic in Latin America, caused by the thermal dimorphic fungus Paracoccidioides brasiliensis. Although some fungal antigens have already been characterized and used for serological diagnosis, cross-reactions have been frequently observed. Thus, the examination of fungal forms in clinical specimens or isolation of P. brasiliensis by culture is still the most frequent method for the diagnosis of this mycosis. In this study, a random peptide phage display library was used to select mimotopes of P. brasiliensis, which were employed as antigens in an indirect enzyme-linked immunosorbent assay. The protective monoclonal antibody against experimental PCM (anti-gp75) was used as molecular target to screen a phage display library. That approach led to a synthetic peptide named P2, which was synthesized and tested against PCM patients’ sera to check whether it was recognized. There was significant recognition of P2 by sera of untreated PCM patients when compared with normal human sera. Sera from treated PCM group, patients with other mycosis or co-infected with HIV had much lower recognition of P2 than untreated patient group. The test showed a sensitivity of 100 and 94.59% of specificity in relation to human sera control. These data indicate a potential use of P2 as diagnostic tool in PCM. Its application for serological diagnosis of PCM may contribute to the development and standardization of simpler, faster and highly reproducible immunodiagnostic tests at low cost

    Search for gamma-ray emission from magnetars with the Fermi Large Area Telescope

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    We report on the search for 0.1-10 GeV emission from magnetars in 17 months of Fermi Large Area Telescope (LAT) observations. No significant evidence for gamma-ray emission from any of the currently-known magnetars is found. The most stringent upper limits to date on their persistent emission in the Fermi-LAT energy range are estimated between ~10^{-12}-10^{-10} erg/s/cm2, depending on the source. We also searched for gamma-ray pulsations and possible outbursts, also with no significant detection. The upper limits derived support the presence of a cut-off at an energy below a few MeV in the persistent emission of magnetars. They also show the likely need for a revision of current models of outer gap emission from strongly magnetized pulsars, which, in some realizations, predict detectable GeV emission from magnetars at flux levels exceeding the upper limits identified here using the Fermi-LAT observations.Comment: ApJ Letters in press; Corresponding authors: Caliandro G. A., Hadasch D., Rea N., Burnett
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