355 research outputs found

    Notas sobre el tamaño del genoma en el híbrido Ranunculus x luizetii (Ranunculaceae) y sus progenitores mediante citometría de flujo

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    Notes on genome size in the hybrid Ranunculus x luizetii (Ranunculaceae) and its parents by flow cytometry.- Flow cytometry was used to estimate the nuclear DNA content in the natural hybrid Ranunculus x luizetii and its parents. Our results indicate that the genome size of the hybrid R. x luizetii is closer to R. pyrenaeus than to R. parnassiifolius, providing an evidence of genome downsizing.Notas sobre el tamaño del genoma en el híbrido Ranunculus x luizetii (Ranunculaceae) y sus progenitores mediante citometría de flujo.- Se ha empleado la citometría de flujo para estimar el contenido de ADN nuclear en el híbrido Ranunculus x luizetii y sus progenitores. Nuestros resultados indican que el tamaño del genoma del híbrido R. x luizetii se acerca más a R. pyrenaeus que a R. parnassiifolius, con una evidencia de reducción del genoma

    ToyLIFE: a computational framework to study the multi-level organisation of the genotype-phenotype map

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    The genotype-phenotype map is an essential object to understand organismal complexity and adaptability. However, its experimental characterisation is a daunting task. Thus, simple models have been proposed and investigated. They have revealed that genotypes differ in their robustness to mutations; phenotypes are represented by a broadly varying number of genotypes, and simple point mutations suffice to navigate the space of genotypes while maintaining a phenotype. Nonetheless, most current models focus only on one level of the map (folded molecules, gene regulatory networks, or networks of metabolic reactions), so that many relevant questions cannot be addressed. Here we introduce toyLIFE, a multi-level model for the genotype-phenotype map based on simple genomes and interaction rules from which a complex behaviour at upper levels emerges - remarkably plastic gene regulatory networks and metabolism. toyLIFE is a tool that permits the investigation of how different levels are coupled, in particular how and where mutations affect phenotype or how the presence of certain metabolites determines the dynamics of toyLIFE gene regulatory networks. The model can easily incorporate evolution through more complex mutations, recombination, or gene duplication and deletion, thus opening an avenue to explore extended genotype-phenotype maps.This work was supported through projects FIS2011-22449 (CFA, PC and JAC) and FIS2011{27569 (SM) of the Spanish MINECO.Publicad

    Catastrophic regime shifts in model ecological communities are true phase transitions

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    Ecosystems often undergo abrupt regime shifts in response to gradual external changes. These shifts are theoretically understood as a regime switch between alternative stable states of the ecosystem dynamical response to smooth changes in external conditions. Usual models introduce nonlinearities in the macroscopic dynamics of the ecosystem that lead to different stable attractors among which the shift takes place. Here we propose an alternative explanation of catastrophic regime shifts based on a recent model that pictures ecological communities as systems in continuous fluctuation, according to certain transition probabilities, between different micro-states in the phase space of viable communities. We introduce a spontaneous extinction rate that accounts for gradual changes in external conditions, and upon variations on this control parameter the system undergoes a regime shift with similar features to those previously reported. Under our microscopic viewpoint we recover the main results obtained in previous theoretical and empirical work (anomalous variance, hysteresis cycles, trophic cascades). The model predicts a gradual loss of species in trophic levels from bottom to top near the transition. But more importantly, the spectral analysis of the transition probability matrix allows us to rigorously establish that we are observing the fingerprints, in a finite size system, of a true phase transition driven by background extinctions.Comment: 19 pages, 11 figures, revised versio

    Identification and Regulation of Interleukin-17 (IL-17) Family Ligands in the Teleost Fish European Sea Bass

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    Interleukin-17 (IL-17) cytokine comprises a family of six ligands in mammals with proinflammatory functions, having an important role in autoimmune disorders and against bacterial, viral, and fungal pathogens. While IL-17A and IL-17F ligands are mainly produced by Th cells (Th17 cells), the rest of the ligands are expressed by other immune and non-immune cells and have different functions. The identification of IL-17 ligands in fish has revealed the presence of six members, counterparts to mammalian ones, and a teleost-specific form, the fish IL-17N. However, tissue distribution, the regulation of gene expression, and scarce bioactivity assays point to similar functions compared to mammalian ones, though this yet to be investigated and confirmed. Thus, we have identified seven IL-17 ligands in the teleost European sea bass (Dicentrarchus labrax), for the first time, corresponding to IL-17A/F1, IL-17A/F2, IL-17A/F3, IL-17C1, IL-17C2, IL-17D, and IL-17N, according to the predicted protein sequences and phylogenetic analysis. They are constitutively and widely transcribed in sea bass tissues, with some of them being mainly expressed in the thymus, brain or intestine. Upon in vitro stimulation of head-kidney leucocytes, the mRNA levels of all sea bass IL-17 ligands were up-regulated by phytohemagglutinin treatment, a well-known T cell mitogen, suggesting a major expression in T lymphocytes. By contrast, the infection of sea bass juveniles with nodavirus (NNV), a very pathogenic virus for this fish species, resulted in the up-regulation of the transcription of IL-17C1 in the head-kidney and of IL-17C1 and IL-17D in the brain, the target tissue for NNV replication. By contrast, NNV infection led to a down-regulated transcription of IL-17A/F1, IL-17A/F2, IL-17C1, IL-17C2, and IL-17D in the head-kidney and of IL-17A/F1 and IL-17A/F3 in the brain. The data are discussed accordingly with the IL-17 ligand expression and the immune response under the different situations testedVersión del editor2,46

    Severe Natural Outbreak of Cryptocaryon irritans in Gilthead Seabream Produces Leukocyte Mobilization and Innate Immunity at the Gill Tissue

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    The protozoan parasite Cryptocaryon irritans causes marine white spot disease in a wide range of fish hosts, including gilthead seabream, a very sensitive species with great economic importance in the Mediterranean area. Thus, we aimed to evaluate the immunity of gilthead seabream after a severe natural outbreak of C. irritans. Morphological alterations and immune cell appearance in the gills were studied by light microscopy and immunohistochemical staining. The expression of several immune-related genes in the gills and head kidney were studied by qPCR, including inflammatory and immune cell markers, antimicrobial peptides (AMP), and cell-mediated cytotoxicity (CMC) molecules. Serum humoral innate immune activities were also assayed. Fish mortality reached 100% 8 days after the appearance of the C. irritans episode. Gill filaments were engrossed and packed without any space between filaments and included parasites and large numbers of undifferentiated and immune cells, namely acidophilic granulocytes. Our data suggest leukocyte mobilization from the head kidney, while the gills show the up-regulated transcription of inflammatory, AMPs, and CMC-related molecules. Meanwhile, only serum bactericidal activity was increased upon infection. A potent local innate immune response in the gills, probably orchestrated by AMPs and CMC, is triggered by a severe natural outbreak of C. irritans.Versión del editor2,46

    Feeding Habits of the Invasive Weakfish (Cynoscion regalis) in the Gulf of Cadiz

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    Weakfish (Cynoscion regalis) has been present in Iberian waters since at least 2011, when it was first recorded in the Guadalquivir estuary. Little is known about the preferences and feeding strategies of weakfish outside of its native range; therefore, in this work, we carried out a comprehensive study between March 2021 and September 2021 to elucidate these matters. In total, the stomach contents of 300 fish were examined. The fish were collected in spring and summer in the Gulf of Cadiz (Spain), with individuals caught ranging from 185 to 590 mm in total length. Due to the sampling period and size range of individuals, ontogenic and seasonal (spring–summer) variations in the diet were also explored. Overall, fish and crustaceans were the dominant groups consumed by weakfish. The European anchovy (Engraulis encrasicolus) and caramote prawn (Penaeus kerathurus) were the most abundant prey in each group. While no differences were found in the percentage of occurrence of fish in the non-empty stomachs analyzed in spring and summer (83%), a small increase was found in the percentage of occurrence of crustaceans from spring (20%) to summer (29%). In addition, the analysis of the results also suggested that weakfish of smaller sizes feed more on crustaceans, while bigger individuals feed mainly on fish. Our findings indicate that weakfish is a fully carnivorous species with a preference for fish. All this is in line with the diet and strategy that weakfish exhibits in its native area and with the first assessment made with the existing population in the Sado Estuary (Portugal). In recent years, due to the appearance of non-native species, there is increasing concern among local fishermen and the local authorities about the reduction in captures of certain species such as Penaeus kerathurus; therefore, this study could help researchers to understand the role of weakfish concerning this matter. The present study contributes to the ecological knowledge about this species in the Iberian Peninsula and the Gulf of Cadiz, helping the local authorities to establish, if needed, an appropriate management program to cope with this recently introduced species

    Ancient DNA Analysis of 8000 B.C. Near Eastern Farmers Supports an Early Neolithic Pioneer Maritime Colonization of Mainland Europe through Cyprus and the Aegean Islands

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    The genetic impact associated to the Neolithic spread in Europe has been widely debated over the last 20 years. Within this context, ancient DNA studies have provided a more reliable picture by directly analyzing the protagonist populations at different regions in Europe. However, the lack of available data from the original Near Eastern farmers has limited the achieved conclusions, preventing the formulation of continental models of Neolithic expansion. Here we address this issue by presenting mitochondrial DNA data of the original Near-Eastern Neolithic communities with the aim of providing the adequate background for the interpretation of Neolithic genetic data from European samples. Sixty-three skeletons from the Pre Pottery Neolithic B (PPNB) sites of Tell Halula, Tell Ramad and Dja'de El Mughara dating between 8,700–6,600 cal. B.C. were analyzed, and 15 validated mitochondrial DNA profiles were recovered. In order to estimate the demographic contribution of the first farmers to both Central European and Western Mediterranean Neolithic cultures, haplotype and haplogroup diversities in the PPNB sample were compared using phylogeographic and population genetic analyses to available ancient DNA data from human remains belonging to the Linearbandkeramik-Alföldi Vonaldiszes Kerámia and Cardial/Epicardial cultures. We also searched for possible signatures of the original Neolithic expansion over the modern Near Eastern and South European genetic pools, and tried to infer possible routes of expansion by comparing the obtained results to a database of 60 modern populations from both regions. Comparisons performed among the 3 ancient datasets allowed us to identify K and N-derived mitochondrial DNA haplogroups as potential markers of the Neolithic expansion, whose genetic signature would have reached both the Iberian coasts and the Central European plain. Moreover, the observed genetic affinities between the PPNB samples and the modern populations of Cyprus and Crete seem to suggest that the Neolithic was first introduced into Europe through pioneer seafaring colonization

    IFE Plant Technology Overview and contribution to HiPER proposal

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    HiPER is the European Project for Laser Fusion that has been able to join 26 institutions and signed under formal government agreement by 6 countries inside the ESFRI Program of the European Union (EU). The project is already extended by EU for two years more (until 2013) after its first preparatory phase from 2008. A large work has been developed in different areas to arrive to a design of repetitive operation of Laser Fusion Reactor, and decisions are envisioned in the next phase of Technology Development or Risk Reduction for Engineering or Power Plant facilities (or both). Chamber design has been very much completed for Engineering phase and starting of preliminary options for Reactor Power Plant have been established and review here

    Petrology and geochemistry of Cardeña-Virgen de La Cabeza pluton (batholith of Los Pedroches)

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    [Resumen] El plutón de Cardeña-Virgen de La Cabeza es uno de los cuerpos intrusivos que integran la unidad granítica del batolito de Los Pedroches. Dentro de este plutón, se ha establecido el emplazamiento sucesivo en el tiempo de: 1) adamellitas biotíticas, 2) granitos biotíticos porfídicos ± cordierita, 3) leucogranitos ± cordierita. Las adamellitas biotíticas muestran localmente paso gradual hacia las facies granodioríticas del batolito. Existe además un importante complejo filoniano que se intruye posteriormente, formado por diques riodacíticos de dirección NO-SE, lamprófidos, aplitas, pegmatitas y filones mineralizados· de cuarzo. Geoquímicamente, la adamellita y el granito biotítico porfídico constituyen una asociación alumino-cafémica de carácter calcoalcalino. Los enclaves anfibólicos (términos cafémicos) poseen carácter metaaluminoso. Los leucogranitos se desvían de la tendencia general definiendo una asociación aluminosa y leucocrática. Los diagramas de variación para elementos mayores, menores, trazas y tierras.raras de adamellitas, granitos biotíticos porfídicos y de granodioritas, rocas, estas últimas, con las que se encuentran íntimamente relacionadas, son compatibles con procesos de diferenciación magmática por cristalización fraccionada a partir de un magma inicial de composición granodiorítica más básico[Abstract] The Cardeña-Virgen de La Cabeza intrusion belongs to the granitic unit of the Los Pedroches batholith. the chronology of the intrusion of the different rocktypes that make up the pluton is as follows: 1) biotitic adamellite, 2) porphyritic, cordierite-bearing, biotitic granite. 3) cordierite bearing leucogranite. The biotitic adamellite locally shows a transition to the granodioritic facies of the batholith. A great amount ofNW-SW oriented dikes with rhyodacitic composition intruded subsequently. Lampophyres, aplites, pegmatites and ore-bearing quartz veins complete the dike complexo Adamellite and biotitic ganite define an aluminous-cafemic association with calcalkaline affinity. The amphibole-bearing enclaves represent the cafemic terms of the series and have a metaaluminous character.The leucogranite deviates from the general trend defining and aluminous, leucocratic association. Variation diagrams for major, minor and trace elements, including REE, of adamallite, porphyritic biotitic granite and granodiorite of the main pluton (which is intimately associated with the Cardeña-Virgen de La Cabeza intrusion) suggest a process of magmatic differentiation through fractional crystallization starting from a slightly more basic granodioritic magma

    Determinación empírica de las competencias para el turismo sostenible

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    El presente trabajo tiene el propósito de determinar las escalas de medida de las competencias genéricas y específicas que permitan a directivos y trabajadores vinculados a la actividad turística en una localidad actuar en consonancia con el modelo de sostenibilidad que se persigue. Se recurrió al método de expertos. Se aplicó un test estadístico para medir la fiabilidad y validez de las escalas de medición. La muestra comprendió 97 directivos y 154 trabajadores de 25 organizaciones vinculadas a la actividad turística de la localidad de Viñales, Pinar del Río. Para el análisis de la fiabilidad se utilizó el Coeficiente Alpha de Cronbach y para el análisis de la validez se recurrió al Análisis Factorial. Se determinó que los directivos y trabajadores vinculados a la actividad turística de una localidad deben poseer seis competencias genéricas, siete competencias específicas de los directivos y cinco competencias específicas de los trabajadores, para contribuir a la sostenibilidad turística
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