211 research outputs found

    Identification of two proteins that interact with the Erp virulence factor from Mycobacterium tuberculosis by using the bacterial two-hybrid system

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    <p>Abstract</p> <p>Background</p> <p>The exported repetitive protein (<it>erp</it>) gene encodes a secreted 36-kDa protein with a central domain containing several proline-glycine-leucine-threonine-serine (PGLTS) repeats. It has been demonstrated that <it>erp </it>is a virulence-associated factor since the disruption of this gene impairs the growth of <it>Mycobacterium bovis </it>and <it>Mycobacterium tuberculosis </it>in mice.</p> <p>Results</p> <p>In order to elucidate the function of Erp we searched for Erp-binding proteins from <it>M. tuberculosis </it>by using a bacterial two-hybrid system. Our results indicate that Erp interacts specifically with two putative membrane proteins, Rv1417 and Rv2617c. Further analysis revealed that the latter two interact with each other, indicating that Rv1417, Rv2617c and Erp are connected through multiple interactions. While Rv1417 is disseminated in several <it>Actinomycetales </it>genera, orthologues of Rv2617c are exclusively present in members of the <it>M. tuberculosis </it>complex (MTC). The central and amino-terminal regions of Erp were determined to be involved in the interaction with Rv1417 and Rv2627c. Erp forms from <it>Mycobacterium smegmatis </it>and <it>Mycobacterium leprae </it>were not able to interact with Rv2617c in two-hybrid assays. Immunolocalization experiments showed that Rv1417 and Rv2617c are found on the cell membrane and Erp on the bacterial cell wall. Finally, comparative genomics and expression studies revealed a possible role of Rv1417 in riboflavin metabolism.</p> <p>Conclusion</p> <p>We identified interactive partners of Erp, an <it>M. tuberculosis </it>protein involved in virulence, which will be the focus of future investigation to decipher the function of the Erp family protein.</p

    Study of the role of Mce3R on the transcription of mce genes of Mycobacterium tuberculosis

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    <p>Abstract</p> <p>Background</p> <p><it>mce3 </it>is one of the four virulence-related <it>mce </it>operons of <it>Mycobacterium tuberculosis</it>. In a previous work we showed that the overexpression of Mce3R in <it>Mycobacterium smegmatis </it>and <it>M. tuberculosis </it>abolishes the expression of <it>lacZ </it>fused to the <it>mce3 </it>promoter, indicating that Mce3R represses <it>mce3 </it>transcription.</p> <p>Results</p> <p>We obtained a knockout mutant strain of <it>M. tuberculosis </it>H37Rv by inserting a hygromycin cassette into the <it>mce3R </it>gene. The mutation results in a significant increase in the expression of <it>mce3 </it>genes either <it>in vitro </it>or in a murine cell macrophages line as it was determined using promoter-<it>lacZ </it>fusions in <it>M. tuberculosis</it>. The abundance of <it>mce1</it>, <it>mce2 </it>and <it>mce4 </it>mRNAs was not affected by this mutation as it was demonstrated by quantitative RT-PCR. The <it>mce3R </it>promoter activity in the presence of Mce3R was significantly reduced compared with that in the absence of the regulator, during the <it>in vitro </it>culture of <it>M. tuberculosis</it>.</p> <p>Conclusion</p> <p>Mce3R repress the transcription of <it>mce3 </it>operon and self regulates its own expression but does not affect the transcription of <it>mce1</it>, <it>mce2 </it>and <it>mce4 </it>operons of <it>M. tuberculosis</it>.</p

    Musculoskeletal evaluation in severe haemophilia A patients from Latin America

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    There is a paucity of literature on haemophilia treatment in Latin American countries, a region characterized by rapidly improving systems of care, but with substantial disparities in treatment between countries. The aim of this study was to evaluate the musculoskeletal status of haemophilia patients from Latin America and to examine the relationship between musculoskeletal status and treatment practices across countries. The Committee of Latin America on the Therapeutics of Inhibitor Groups conducted a survey of its member country representatives on key aspects of haemophilia treatment in 10 countries. Musculoskeletal status of patients was obtained during routine comprehensive evaluations between March 2009 and March 2011. Eligible patients had severe haemophilia A (factor VIII <1%) without inhibitors (<0.6 BU mL−1) and were ≄5 years of age. Musculoskeletal status was compared between three groups of countries, based primarily on differences in the availability of long‐term prophylaxis. Overall, 143 patients (5–66 years of age) were enrolled from nine countries. In countries where long‐term prophylaxis had been available for at least 10 years (Group A), patients aged 5–10 years had significantly better mean World Federation of Hemophilia clinical scores, fewer target joints and fewer affected joints than patients from countries where long‐term prophylaxis has been available for about 5 years (Group B) or was not available (Group C). In Latin America, the musculoskeletal status of patients with severe haemophilia without inhibitors has improved significantly in association with the provision of long‐term prophylaxis. As more countries in Latin America institute this practice, further improvements are anticipated

    New remains of Nothrotheriinae (Mammalia, Xenarthra) from Late Pleistocene fluvial deposits of Northern Pampa (Santa Fe Province, Argentina)

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    In this contribution the record of a Nothrotheriinae (Xenarthra, Tardigrada) ground sloth is reported from the Late Pleistocene of the Northern Pampa of Santa Fe Province, Argentina. The stratigraphic unit where the fossil was collected corresponds to fluvial-palustrine sediments of the TimbĂșes Formation, outcropping along the Carcarañå River valley. The relative stratigraphic position of this lithostratigraphic unit, observed in several sections mainly on the ParanĂĄ River cliffs near Carcarañå River distal area, suggests that it was deposited during the Last Interglacial Stage. The specimen (MPAHND-135), assigned to Nothrotherium cf. torresi, is represented by the proximal two-thirds of a left femur that shows a prominent lesser trochanter and no connection between the third trochanter and the ectepicondyle. The presence of Nothrotherium cf. torresi in sediments related to humid conditions supports the idea that Nothrotheriinae had great ecological tolerance and was capable of inhabiting climates ranging from cold and arid, as was previously proposed, to warm and humid.Fil: Vezzosi, RaĂșl Ignacio. Provincia de Entre RĂ­os. Centro de Investigaciones CientĂ­ficas y Transferencia de TecnologĂ­a a la ProducciĂłn. Universidad AutĂłnoma de Entre RĂ­os. Centro de Investigaciones CientĂ­ficas y Transferencia de TecnologĂ­a a la ProducciĂłn. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Centro de Investigaciones CientĂ­ficas y Transferencia de TecnologĂ­a a la ProducciĂłn; ArgentinaFil: Brandoni, Diego. Provincia de Entre RĂ­os. Centro de Investigaciones CientĂ­ficas y Transferencia de TecnologĂ­a a la ProducciĂłn. Universidad AutĂłnoma de Entre RĂ­os. Centro de Investigaciones CientĂ­ficas y Transferencia de TecnologĂ­a a la ProducciĂłn. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Centro de Investigaciones CientĂ­ficas y Transferencia de TecnologĂ­a a la ProducciĂłn; ArgentinaFil: Brunetto, Ernesto. Provincia de Entre RĂ­os. Centro de Investigaciones CientĂ­ficas y Transferencia de TecnologĂ­a a la ProducciĂłn. Universidad AutĂłnoma de Entre RĂ­os. Centro de Investigaciones CientĂ­ficas y Transferencia de TecnologĂ­a a la ProducciĂłn. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Centro de Investigaciones CientĂ­ficas y Transferencia de TecnologĂ­a a la ProducciĂłn; ArgentinaFil: Zalazar, Maria Cecilia. Universidad Nacional del Litoral; Argentin

    Chromatin-associated regulation of sorbitol synthesis in flower buds of peach

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    [EN] Key message PpeS6PDH gene is postulated to mediate sorbitol synthesis in flower buds of peach concomitantly with specific chromatin modifications. Abstract Perennial plants have evolved an adaptive mechanism involving protection of meristems within specialized structures named buds in order to survive low temperatures and water deprivation during winter. A seasonal period of dormancy further improves tolerance of buds to environmental stresses through specific mechanisms poorly known at the molecular level. We have shown that peach PpeS6PDH gene is down-regulated in flower buds after dormancy release, concomitantly with changes in the methylation level at specific lysine residues of histone H3 (H3K27 and H3K4) in the chromatin around the translation start site of the gene. PpeS6PDH encodes a NADPH-dependent sorbitol-6-phosphate dehydrogenase, the key enzyme for biosynthesis of sorbitol. Consistently, sorbitol accumulates in dormant buds showing higher PpeS6PDH expression. Moreover, PpeS6PDH gene expression is affected by cold and water deficit stress. Particularly, its expression is up-regulated by low temperature in buds and leaves, whereas desiccation treatment induces PpeS6PDH in buds and represses the gene in leaves. These data reveal the concurrent participation of chromatin modification mechanisms, transcriptional regulation of PpeS6PDH and sorbitol accumulation in flower buds of peach. In addition to its role as a major translocatable photosynthate in Rosaceae species, sorbitol is a widespread compatible solute and cryoprotectant, which suggests its participation in tolerance to environmental stresses in flower buds of peach.This work was funded by the Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA)-FEDER (RF2013-00043-C02-02) and the Ministry of Science and Innovation of Spain (AGL2010-20595). 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    Nightside condensation of iron in an ultra-hot giant exoplanet

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    Ultra-hot giant exoplanets receive thousands of times Earth's insolation. Their high-temperature atmospheres (>2,000 K) are ideal laboratories for studying extreme planetary climates and chemistry. Daysides are predicted to be cloud-free, dominated by atomic species and substantially hotter than nightsides. Atoms are expected to recombine into molecules over the nightside, resulting in different day-night chemistry. While metallic elements and a large temperature contrast have been observed, no chemical gradient has been measured across the surface of such an exoplanet. Different atmospheric chemistry between the day-to-night ("evening") and night-to-day ("morning") terminators could, however, be revealed as an asymmetric absorption signature during transit. Here, we report the detection of an asymmetric atmospheric signature in the ultra-hot exoplanet WASP-76b. We spectrally and temporally resolve this signature thanks to the combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by -11+/-0.7 km s-1 on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside. In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. Iron must thus condense during its journey across the nightside.Comment: Published in Nature (Accepted on 24 January 2020.) 33 pages, 11 figures, 3 table

    Prospective individual patient data meta-analysis of two randomized trials on convalescent plasma for COVID-19 outpatients

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    Data on convalescent plasma (CP) treatment in COVID-19 outpatients are scarce. We aimed to assess whether CP administered during the first week of symptoms reduced the disease progression or risk of hospitalization of outpatients. Two multicenter, double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when = 50 years and symptomatic for <= 7days were included. The intervention consisted of 200-300mL of CP with a predefined minimum level of antibodies. Primary endpoints were a 5-point disease severity scale and a composite of hospitalization or death by 28 days. Amongst the 797 patients included, 390 received CP and 392 placebo; they had a median age of 58 years, 1 comorbidity, 5 days symptoms and 93% had negative IgG antibody-test. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The odds ratio (OR) of CP for improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311); OR for hospitalization or death was 0.919 (CI 0.592-1.416). CP effect on hospital admission or death was largest in patients with <= 5 days of symptoms (OR 0.658, 95%CI 0.394-1.085). CP did not decrease the time to full symptom resolution

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

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    Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe
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