1,213 research outputs found

    Ediacaran Obduction of a Fore-Arc Ophiolite in SW Iberia: A Turning Point in the Evolving Geodynamic Setting of Peri- Gondwana

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    The Calzadilla Ophiolite is an ensemble of mafic and ultramafic rocks that represents the transition between lower crust and upper mantle of a Cadomian (peri-Gondwanan) fore arc. Mapping and structural analysis of the ophiolite demonstrates that it was obducted in latest Ediacaran times, because the Ediacaran-Early Cambrian sedimentary series (Malcocinado Formation) discordantly covers it. The ophiolite and emplacement-related structures are affected by Variscan deformation (Devonian-Carboniferous), which includes SW verging overturned folds (D1) and thrusts (D2), upright folds (D3), extensional faults (D4), and later faults (D5). These phases of deformation are explained in the context of Variscan tectonics as the result of the progressive collision between Gondwana and Laurussia. Qualitative unstraining of Variscan deformation reveals the primary geometry of Ediacaran-Cambrian structures and uncovers the generation of east verging thrusts as responsible for the primary obduction of the Calzadilla Ophiolite. Restoration of planar and linear structures associated with this event indicates an Ediacaran, east directed obduction of the ophiolite, that is, emplacement of the Cadomian fore arc onto inner sections of the northern margin of Gondwana. According to regional data, the obduction separates two extension-dominated stages in the tectonic evolution of the African margin of northern Gondwana preserved in southern Europe. Preobduction extension brought about the onset and widening of fore-arc and back-arc basins in the external part of the continent, while postobduction extension facilitated the formation of extensional migmatitic domes, an oceanward migration of back-arc spreading centers across peri-Gondwana, and the eventual opening of a major basin such as the Rheic Ocean

    Cannabinoid CB<sub>2</sub> Receptor Modulation by the Transcription Factor NRF2 is Specific in Microglial Cells

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    Nuclear factor erythroid 2-related factor 2 (NRF2) is a pleiotropic transcription factor that has neuroprotective and anti-inflammatory effects, regulating more than 250 genes. As NRF2, cannabinoid receptor type 2 (CB2) is also implicated in the preservation of neurons against glia-driven inflammation. To this concern, little is known about the regulation pathways implicated in CB2 receptor expression. In this study, we analyze whether NRF2 could modulate the transcription of CB2 in neuronal and microglial cells. Bioinformatics analysis revealed an antioxidant response element in the promoter sequence of the CB2 receptor gene. Further analysis by chemical and genetic manipulations of this transcription factor demonstrated that NRF2 is not able to modulate the expression of CB2 in neurons. On the other hand, at the level of microglia, the expression of CB2 is NRF2-dependent. These results are related to the differential levels of expression of both genes regarding the brain cell type. Since modulation of CB2 receptor signaling may represent a promising therapeutic target with minimal psychotropic effects that can be used to modulate endocannabinoid-based therapeutic approaches and to reduce neurodegeneration, our findings will contribute to disclose the potential of CB2 as a novel target for treating different pathologies.This work was supported by the Spanish Ministry of Economy and Competitiveness (Grants Refs. SAF2016-76520-R to ILB and BFU2016-75973-R to MDG)

    Combined use of a new SNP-based assay and multilocus SSR markers to assess genetic diversity of Xylella fastidiosa subsp. pauca infecting citrus and coffee plants

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    Two haplotypes of Xylella fastidiosa subsp. pauca (Xfp) that correlated with their host of origin were identified in a collection of 90 isolates infecting citrus and coffee plants in Brazil, based on a single-nucleotide polymorphism in the gyrB sequence. A new single-nucleotide primer extension (SNuPE) protocol was designed for rapid identification of Xfp according to the host source. The protocol proved to be robust for the prediction of the Xfp host source in blind tests using DNA from cultures of the bacterium, infected plants, and insect vectors allowed to feed on Xfp-infected citrus plants. AMOVA and STRUCTURE analyses of microsatellite data separated most Xfp populations on the basis of their host source, indicating that they were genetically distinct. The combined use of the SNaPshot protocol and three previously developed multilocus SSR markers showed that two haplotypes and distinct isolates of Xfp infect citrus and coffee in Brazil and that multiple, genetically different isolates can be present in a single orchard or infect a single tree. This combined approach will be very useful in studies of the epidemiology of Xfp-induced diseases, host specificity of bacterial genotypes, the occurrence of Xfp host jumping, vector feeding habits, etc., in economically important cultivated plants or weed host reservoirs of Xfp in Brazil and elsewhere [Int Microbiol 2015; 18(1):13-24]Keywords: Citrus variegated chlorosis &middot; coffee leaf scorch &middot; vector transmission&middot; xylem-limited bacteria &middot; haplotype characterization &middot; host-plant associatio

    Reference standard for the uncertainty estimation of X–ray Computed Tomography measurements of complex macro-and micro-geometries

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    Traditionally, measuring both macro and micro geometries with a single device has been challenging in metrology. Coordinate Measuring Machines (CMM) are common devices for the inspection of large features, while optical microscopes can achieve resolutions in the order of micrometers in small areas. X-Ray Computed Tomography (XCT) has become a solution not only to characterize both micro and macro geometries, but also to inspect internal features without destroying the sample. In this field, various reference standards have been developed in order to verify the capabilities of XCT systems, these artefacts include geometrical features or profiles for roughness inspection. This paper shows the design and develompent of a reference standard for XCT test which includes internal and external geometrical features and profiles for macro and micro geometrical inspection. The model is manufactured by additive manufacturing (AM), easing the process of fabrication of the artefact and allowing to test the capabilities of this technology to produce reference standards

    Scanning Electron Microscope Study of Wohlfahrtia magnifica (Schiner, 1862) (Diptera: Sarcophagidae) I. Structures with Parasitic and Possible Taxonomic Meaning

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    The larval development of Wohlfahrtia magnifica (the most important dipteran causing sheep myiasis in the Palearctic region) has been studied by means of scanning electron microscopy. The ultrastructure of mouth-hooks, oral ridges, labial lobes, body spines and anterior and posterior peritremes is described for the first time. Their possible adaptations to a parasitic lifeway are also discussed. Thus, the use of new structures in the Sarcophagidae taxonomy is proposed from the point of view of their ultrastructure and adaptative morphology

    Extending Qualitative Spatial Theories with Emergent Spatial Concepts: An Automated Reasoning Approach

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    Qualitative Spatial Reasoning is an exciting research field of the Knowledge Representation and Reasoning paradigm whose application often requires the extension, refinement or combination of existent theories (as well as the associated calculus). This paper addresses the issue of the sound spatial interpretation of formal extensions of such theories; particularly the interpretation of the extension and the desired representational features. The paper shows how to interpret certain kinds of extensions of Region Connection Calculus (RCC) theory. We also show how to rebuild the qualitative calculus of these extensions.Junta de Andalucía TIC-606

    Single-Site Root Inoculations on Eggplant with Microsclerotia of Verticillium dahliae

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    ¿ For many soilborne plant pathogens, disease results from multiple root infections. Studying the infection dynamics of single or multiple propagules of these pathogens applied at one site of the root system may be the basis for understanding the development of disease caused by multiple root infections. The effect of single-site inoculations of roots of eggplant seedlings with microsclerotia of the wilt-causing fungus Verticillium dahliae, was studied. Experiments were conducted using specially designed pots which enabled the incorporation and removal of inoculum in the soil. Inoculations were carried out by placing microsclerotia, firmly embedded in small sections of polypropylene screen filter, directly below the growing tip of the main root of young eggplant seedlings. Three to 4 days after inoculation, the root had grown over the screen filter, and the filter was removed. Root platings showed high infection levels at the inoculation site, but also several (discrete) root infections were noted some distance above and below the site of inoculation. Exposure of the root to the lowest number of microsclerotia (26/inoculation site) was sufficient to lead to up to 65% root infections. Number of plants with root infections declined over time, ranging from a maximum of 65-100% 2-4 wk after inoculation, to 10-29% at 6-7 wk after inoculation. Apparently, V. dahliae died in nonsystemic infections after some time

    Phosphomannosylation and the functional analysis of the extended Candida albicans MNN4-like gene family

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    We thank Luz A. López-Ramírez (Universidad de Guanajuato) for technical assistance. This work was supported by Consejo Nacional de Ciencia y Tecnología (ref. CB2011/166860; PDCPN2014-247109, and FC 2015-02-834), Universidad de Guanajuato (ref. 000025/11; 0087/13; ref. 1025/2016; Convocatoria Institucional para Fortalecer la Excelencia Académica 2015; CIFOREA 89/2016), Programa de Mejoramiento de Profesorado (ref. UGTO-PTC-261), and Red Temática Glicociencia en Salud (CONACYT-México). NG acknowledges the Wellcome Trust (086827, 075470, 101873, and 200208) and MRC Centre for Medical Mycology for funding (N006364/1). KJ was supported by a research visitor grant to Aberdeen from China Scholarship Council (CSC No. 201406055024). The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmicb.2017.02156/full#supplementary-materialPeer reviewedPublisher PD

    One-step warming does not affect the in vitro viability and cryosurvival of cryotop-vitrified donkey embryos

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    The objective of this study was to compare the effects of two warming protocols (three-step vs. one-step dilution) on embryo quality, post-warming embryo survival and embryo cell viability of donkey embryos vitrified by the Cryotop method. Twenty, Day 7–8, grade 1–2 donkey embryos were measured, morphologically evaluated and vitrified using the Cryotop technique. Embryos were then randomly warmed using two different warming procedures: (i) W3 (three-step dilution; n = 11): embryos were warmed in 1 M, 0.5 M and 0 M sucrose, and (ii) W1/0.5 (one-step dilution; n = 9): embryos were warmed directly in 0.5 M sucrose. After 3 and 24 h of warming, the embryos were measured and evaluated for their morphology, developmental stage and viability (Propidium Iodide-Hoechst 33,342 dyes). Although both treatments decreased embryo quality after warming (P 0.05) were observed between protocols in terms of post-warming embryo quality, diameter and embryo survival. Greater percentages of dead cells (P < 0.001) were observed when embryos were warmed directly in 0.5 M sucrose (one-step dilution) when compared to the three-step protocol. The percentage of ruptured embryos was 27.3% and 0% in W3 and W1/0.5 protocols (P = 0.0893), respectively. In conclusion, warming Cryotop-vitrified donkey embryos directly in 0.5 M sucrose had no negative effects on embryo quality and post-warming embryo survival. Moreover, one-step protocol may help to prevent rupture when donkey embryos warmed directly in 0.5 M sucrose. These results observed in vitro must be verified by embryo transfer

    Evaluación del comportamiento sísmico de la estructura original y modificada del Mercado de Verónicas en Murcia (España)

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    In this manuscript, it is presented, a case-study about the assessment of the seismic behaviour of Veronicas Market. Its structure, initially constituted by steel trusses supported on masonry walls, was subsequently modified by the addition of a mezzanine supported on reinforced concrete piers. Applying the capacity spectrum method, based on an updated nonlinear finite element model, the performance levels of both the original and modified structure have been compared to assess the effects originated by the change in the transmission mechanism of the seismic loads.En este artículo, se presenta, un caso en estudio sobre la evaluación del comportamiento sísmico del Mercado de Verónicas. Su estructura, originalmente constituida por cerchas metálica apoyadas sobre muros de fábrica fue posteriormente modificada por la incorporación de una entreplanta con pilares de hormigón armado. Aplicando el método del espectro de capacidad, con base en un modelo calibrado no-lineal de elementos finitos, se han comparado los niveles de desempeño de la estructura original y modificada para valorar los efectos originados por el cambio en el mecanismo de transmisión de las cargas sísmicas
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