11,953 research outputs found

    Phylogenetic and Transcriptomic Analyses of Vision in Two Cave Adapted Crustaceans, Asellus aquaticus (Isopoda: Asellidae) and Niphargus hrabei (Amphipoda: Niphargidae).

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    The unique characteristics of aquatic caves and of their predominantly crustacean biodiversity nominate them as ideal study subjects for evolutionary biology. The present dissertation capitalizes on a perfect natural experiment, the Molnar Janos thermal cave system in Budapest, Hungary. This intricate freshwater cave system and the immediately adjacent Malom Lake present the ideal opportunity to address questions of colonization, adaptation, and evolution. Despite marked environmental differences between the cave and surface waters, both localities are inhabited by natural populations of two emerging model cave species, the isopod Asellus aquaticus and the amphipod Niphargus hrabei. In the present dissertation, I first conduct an extensive literature review to examine and discuss the role that molecular methodologies have played in the study of cave biology. Additionally, I discuss the potential of “speleogenomic” methodologies to address long-standing questions in cave and evolutionary biology in fields such as biodiversity, phylogeography, and evolution. I then investigate the phylogeographic patterns and divergence-time estimates between surface and cave populations of the aforementioned species to elucidate mechanisms and processes driving the colonization of subterranean environments. These populations’ phylogenies then serve as robust frameworks on which to evaluate the transcriptional basis behind the divergence of traits involved in troglomorphy, namely vision. RNA sequencing approaches are used to identify and evaluate differences in the transcription of photoreception genes and pathways to in subterranean vs. surface populations. To achieve so, in a scalable manner suitable for modern sequencing technologies, here I produce a bioinformatics pipeline that allows for an accurate and efficient identification of genes present in a transcriptome that are involved in photoreception and visual pathways. I then use this bioinformatics pipeline to depict, in a phylogenetically informed context, the transcriptional basis behind photoreception and vision in A. aquaticus and N. hrabei, and the role these traits play in cave adaptation, and in the evolution of troglomorphy in the subphylum Crustacea. With the findings herein, the present dissertation aims to provide a framework for the discovery of evolutionarily significant molecular mechanisms that permit the survival and evolution of life in caves and other extreme environments

    Perinatal Tuberculosis: Is it a Forgotten Disease?

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    Perinatal tuberculosis is an uncommon condition but with a high mortality and a challenging diagnosis. We present four cases of perinatal tuberculosis managed between 1991-2014 in a Spanish Tertiary Hospital. The infection should be considered in patients with progressive respiratory symptoms and with a poor response to conventional antibiotic therapy, especially in those with positive epidemiologic risk. Bronchoscopy can be a useful tool for diagnosis

    The nucleotidohydrolases DCTPP1 and dUTPase are involved in the cellular response to decitabine

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    Decitabine (5-aza-2acute;-deoxycytidine, aza-dCyd) is an anticancer drug used clinically for the treatment of myelodysplastic syndromes and acute myeloid leukemia that can act as a DNA-demethylating or genotoxic agent in a dose-dependent manner. On the other hand, DCTPP1 and dUTPase are two "house-cleaning" nucleotidohydrolases involved in the elimination of non-canonical nucleotides. Here we show that exposure of HeLa cells to decitabine up-regulates the expression of several pyrimidine metabolic enzymes including DCTPP1, dUTPase, dCMP deaminase and thymidylate synthase thus suggesting their contribution to the cellular response to this anticancer nucleoside. We present several lines of evidence supporting that, in addition to the formation of aza-dCTP, an alternative cytotoxic mechanism for decitabine may involve the formation of aza-dUMP, a potential thymidylate synthase inhibitor. Indeed, dUTPase or DCTPP1 down-regulation enhanced the cytotoxic effect of aza-dCyd producing an accumulation of nucleoside triphosphates containing uracil as well as uracil misincorporation and double-strand breaks in genomic DNA. Moreover, DCTPP1 hydrolyzes the triphosphate form of decitabine with similar kinetic efficiency than its natural substrate dCTP and prevents decitabine-induced global DNA demethylation. The data suggest that the nucleotidohydrolases DCTPP1 and dUTPase are factors involved in the mode of action of decitabine with potential value as enzymatic targets to improve decitabine-based chemotherapy

    Búsqueda de dianas en Podosphaera Xanthii para el desarrollo de nuevas fitoterapias antifúngicas

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    La resistencia a fungicidas en uno de los principales problemas de la agricultura y esto es especialmente patente en el caso de los oídios. En España y en las principales áreas productoras del mundo, el oídio de las cucurbitáceas es una amenaza muy grave, y Podosphaera xanthii es considerado como el principal agente causante de la enfermedad. Hasta la fecha, la aplicación de fungicidas y el uso de variedades resistentes son las principales herramientas para el control de la enfermedad. En cualquier caso, el oídio sigue imponiendo serias limitaciones en la producción agrícola, siendo necesario el desarrollo de nuevas estrategias de control. En este estudio se pretende proporcionar información sobre las bases moleculares de P. xanthii que pueda ser de utilidad para el desarrollo de nuevas herramientas de fitoprotección. Para lograr este objetivo, estamos centrando nuestra atención en un conjunto de proteínas fúngicas carentes de función, determinado en un estudio anterior. Ante la falta de homología con proteínas funcionalmente anotadas, para conocer la posible función de dichas proteínas, en primer lugar, llevamos a cabo un análisis in silico detallado de las proteínas que incluye modelado 3D, predicción de posibles ligandos e identificación de dominios funcionales. En segundo lugar, para la identificación de proteínas clave para la patogénesis de P. xanthii, silenciamos proteínas del hongo con función predicha bioinformáticamente mediante silenciamiento génico inducido por hospedador (HIGS) empleando Agrobacterium tumefaciens como vector para la expresión transitoria de construcciones de silenciamiento en células de melón, y desde ellas, al hongo diana. Finalmente, las proteínas con un fenotipo claro de silenciamiento serán seleccionadas para la caracterización de su actividad biológica. En este congreso se mostrarán los resultados más relevantes obtenidos hasta la fecha, relativos a la asimilación de azufre.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Este trabajo ha sido financiado por una ayuda del Programa Estatal de I+D+i Orientada a los Retos de la Sociedad (AGL2016-76216-C2-1-R), cofinanciada con fondos FEDER (UE). Los autores agredecen además ayudas del Plan Propio de Investigación de la Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Fragmented host distribution and trombiculid parasitic load: Eutrombicula araucanensis and Liolaemus pictus in Chile

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    International audienceHabitat fragmentation produced by human impacts can generate changes in the distribution and abundance of populations across their geographic ranges. The chigger mites are ectoparasites that are widely distributed on a wide range of species. The distribution depends of the characteristics of the host and of the habitat where said species is found. As the host distribution is highly dependent on environmental factors, chigger mites are good study models to test geographical distribution patterns. The main objective of this study was to determine variation in abundance of Eutrombicula araucanensis, parasite on Liolaemus pictus, by testing three hypotheses: abundant centre hypothesis, abundance optimum hypothesis and latitudinal distribution pattern. For this purpose, mites from 147 individuals from 23 localities along the distribution of L. pictus were extracted. The three distribution models evaluated in the present study were not adequate to represent the geographical structure of parasitic mites on L. pictus. No association between the distance from the area of greatest species abundance and relative intensity, or association with the distance to the mite’s distribution centre was observed. In addition, no latitudinal distribution pattern was observed. Temperate forest fragmentation may influence the population density of mites, with each forest patch having different optimal conditions for development. The heterogeneity makes it difficult to find a clear distribution pattern

    A cross-sectional analysis of the association between physical activity, depression, and all-cause mortality in Americans over 50 years old

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    Depression is estimated to be the second leading cause of disability in the United States and is associated with a 52% increased risk of death. Lifestyle components may have an important role in depression pathogenesis. The aims of this study were to analyze the association of meeting the physical activity (PA) recommendation guidelines and depression, and to analyze the all-cause mortality risk of the joint association of PA and depression. This cross-sectional study included 7201 participants from the 2007–2014 National Health and Nutrition Examination Survey aged ≥ 50 years and linked to National Death Index records through December 31, 2015. Depression was defined as a score ≥ 10 using the Patient Health Questionnaire (PHQ-9). PA was self-reported, and total PA was used to classify participants as more active (≥ 600 MET-min/week) or less active (< 600 MET-min/week). The odds ratios for depression were examined according to be more active or less active. The hazard ratios (HR) for the association of PA level and depression status with all-cause mortality were examined. Being more active was associated with reduced odds for depression. Compared with less active participants with depression, those who were more active and having depression had HR 0.45 (95% CI 0.22, 0.91, p = 0.026) for all-cause mortality. Being more active is associated with lower odds for depression and seems to be a protective factor against the increased all-cause mortality risk due to depression

    Quantitative Analysis of the Cervical Texture by Ultrasound and Correlation with Gestational Age

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    Objectives: Quantitative texture analysis has been proposed to extract robust features from the ultrasound image to detect subtle changes in the textures of the images. The aim of this study was to evaluate the feasibility of quantitative cervical texture analysis to assess cervical tissue changes throughout pregnancy. Methods: This was a cross-sectional study including singleton pregnancies between 20.0 and 41.6 weeks of gestation from women who delivered at term. Cervical length was measured, and a selected region of interest in the cervix was delineated. A model to predict gestational age based on features extracted from cervical images was developed following three steps: data splitting, feature transformation, and regression model computation. Results: Seven hundred images, 30 per gestational week, were included for analysis. There was a strong correlation between the gestational age at which the images were obtained and the estimated gestational age by quantitative analysis of the cervical texture (R = 0.88). Discussion: This study provides evidence that quantitative analysis of cervical texture can extract features from cervical ultrasound images which correlate with gestational age. Further research is needed to evaluate its applicability as a biomarker of the risk of spontaneous preterm birth, as well as its role in cervical assessment in other clinical situations in which cervical evaluation might be relevant

    MRI Deep Learning-Based Solution for Alzheimer’s Disease Prediction

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    Background: Alzheimer’s is a degenerative dementing disorder that starts with a mild memory impairment and progresses to a total loss of mental and physical faculties. The sooner the diagnosis is made, the better for the patient, as preventive actions and treatment can be started. Al though tests such as the Mini-Mental State Tests Examination are usually used for early identification, diagnosis relies on magnetic resonance imaging (MRI) brain analysis. Methods: Public initiatives such as the OASIS (Open Access Series of Imaging Studies) collection provide neuroimaging datasets openly available for research purposes. In this work, a new method based on deep learning and image processing techniques for MRI-based Alzheimer’s diagnosis is proposed and compared with previous literature works. Results: Our method achieves a balance accuracy (BAC) up to 0.93 for image-based automated diagnosis of the disease, and a BAC of 0.88 for the establishment of the disease stage (healthy tissue, very mild and severe stage). Conclusions: Results obtained surpassed the state-of-the-art proposals using the OASIS collection. This demonstrates that deep learning-based strategies are an effective tool for building a robust solution for Alzheimer’s-assisted diagnosis based on MRI data.This work was partially supported by the SUPREME project. This project has received funding from the Basque Government’s Industry Department HAZITEK program under agreement ZE-2019/00022. This research has also received funding from the Basque Government’s Industry Department under the ELKARTEK program’s project ONKOTOOLS under agreement KK-2020/0006

    Método de muestreo secuencial-enumerativo y binomial para Calepitrimerus vitis (Nalepa, 1905) (Acari: Eriophyidae)

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    El eriófído Calepitrimerus vitis (Nal.) es la especie responsable de la afección conocida como acariosis de la vid. En Rioja, esta plaga puede provocar importantes pérdidas, sobre todo en aquellos años cuyas primaveras son frías. Se ha desarrollado un método de muestreo secuencial-enumerativo y un método de muestreo binomial para estimar la densidad poblacional de este acaro. Con el propósito de caracterizar la distribución espacial de C. vitis se han calculado los índices de agregación de Taylor e Iwao, comprobando que el ajuste es mejor para los índices de Taylor, siendo b=l,79. En el muestreo enumerativo se han obtenido las curvas que relacionan la densidad poblacional del erió- fído con el tamaño de la muestra, con una precisión E=0,25, basánsose en los índices de Taylor encontrados. El muestreo binomial para la estimación de la densidad poblacional se ha desarrollado en base a obtener la relación existente entre el número de ácaros por hoja y el porcentaje de hojas ocupadas.The eriophyid mite Calepitrimerus vitis (Nal.) is an important pest in vineyards of Rioja (Spain). The agregation indexes of this mite have been calculated, and diferent sampling plans for this species have been developed, including enumerative and binomial schemes to estimate population density. Taylor's index has given better fitting than Iwao's. The coefficent b of Taylor is 1,79. To develop an enumerative sampling plan, the sample size based on Taylor's index has been calculated with a 25% precision level. It has been developed a binomial sampling scheme based on de relationship between the number of individuals per leaf and the proportion of leafs occupied by C. vitis
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