216 research outputs found

    Multivariate analysis of morphology, behaviour, growth and developmental timing in hybrids brings new insights into the divergence of sympatric Arctic charr morphs

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    This work was fully funded by the Icelandic Centre of Research, RANNÍS (Icelandic Research Fund grant no.173802-051).Background: Studying the development of fitness related traits in hybrids from populations diverging in sympatry is a fundamental approach to understand the processes of speciation. However, such traits are often affected by covariance structures that complicate the comprehension of these processes, especially because the interactive relationships between traits of different nature (e.g. morphology, behaviour, life-history) remain largely unknown in this context. In a common garden setup, we conducted an extensive examination of a large suit of traits putatively involved in the divergence of two morphs of Arctic charr (Salvelinus alpinus), and investigated the consequences of potential patterns of trait covariance on the phenotype of their hybrids. These traits were measured along ontogeny and involved growth, yolk sac resorption, developmental timing (hatching and the onset of exogeneous feeding), head morphology and feeding behaviour. Results: Growth trajectories provided the strongest signal of phenotypic divergence between the two charr. Strikingly, the first-generation hybrids did not show intermediate nor delayed growth but were similar to the smallest morph, suggesting parental biases in the inheritance of growth patterns. However, we did not observe extensive multivariate trait differences  between the two morphs and their hybrids. Growth was linked to head morphology (suggesting that morphological variations in early juveniles relate to simple allometric effects) but this was the only strong signal of covariance observed between all the measured traits. Furthermore, we did not report evidence for differences in overall phenotypic variance between morphs, nor for enhanced phenotypic variability in their hybrids. Conclusion: Our study shed light on the multivariate aspect of development in a context of adaptive divergence. The lack of evidence for the integration of most traits into a single covariance structure suggested that phenotypic constraints may not always favour nor impede divergence toward ecological niches differing in numerous physical and ecological variables, as observed in the respective habitats of the two charr. Likewise, the role of hybridization as a disruptive agent of trait covariance may not necessarily be significant in the evolution of populations undergoing resource polymorphism.Publisher PDFPeer reviewe

    Quantitative Dietary Fingerprinting (QDF)-A Novel Tool for Comprehensive Dietary Assessment Based on Urinary Nutrimetabolomics

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    Accurate dietary assessment is a challenge in nutritional research, needing powerful and robust tools for reliable measurement of food intake biomarkers. In this work, we have developed a novel quantitative dietary fingerprinting (QDF) approach, which enables for the first time the simultaneous quantitation of about 350 urinary food-derived metabolites, including (poly)phenolic aglycones, phase II metabolites, and microbial-transformed compounds, as well as other compounds (e.g., glucosinolates, amino acid derivatives, methylxanthines, alkaloids, and markers of alcohol and tobacco consumption). This method was fully validated for 220 metabolites, yielding good linearity, high sensitivity and precision, accurate recovery rates, and negligible matrix effects. Furthermore, 127 additional phase II metabolites were also included in this method after identification in urines collected from acute dietary interventions with various foods. Thus, this metabolomic approach represents one-step further toward precision nutrition and the objective of improving the accurateness and comprehensiveness in the assessment of dietary patterns and lifestyles

    On the de Haas - van Alphen oscillations in quasi-two-dimensional metals: effect of the Fermi surface curvature

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    Here, we present the results of theoretical analysis of the de Haas-van Alphen oscillations in quasi-two-dimensional normal metals. We had been studying effects of the Fermi surface (FS) shape on these oscillations. It was shown that the effects could be revealed and well pronounced when the FS curvature becomes zero at cross-sections with extremal cross-sectional areas. In this case both shape and amplitude of the oscillations could be significantly changed. Also, we analyze the effect of the FS local geometry on the angular dependencies of the oscillation amplitudes when the magnetic field is tilted away from the FS symmetry axis by the angle Ξ.\theta. We show that a peak appears at ξ≈0\theta \approx 0 whose height could be of the same order as the maximum at the Yamaji angle. This peak emerges when the FS includes zero curvature cross-sections of extremal areas. Such maximum was observed in experiments on the α−(BETS)4TIHg(SeCN)4.\alpha-(BETS)_4TIHg(SeCN)_4. The obtained results could be applied to organic metals and other quasi-two-dimensional compounds.Comment: 9 pages, 4 figures, text added, references adde

    Systematic analysis of the polyphenol metabolome using the Phenol-Explorer database

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    SCOPE: The Phenol-Explorer web database details 383 polyphenol metabolites identified in human and animal biofluids from 221 publications. Here we exploit these data to characterize and visualize the polyphenol metabolome, the set of all metabolites derived from phenolic food components. METHODS AND RESULTS: Qualitative and quantitative data on 383 polyphenol metabolites as described in 424 human and animal intervention studies were systematically analyzed. Of these metabolites, 301 were identified without prior enzymatic hydrolysis of biofluids, and included glucuronide and sulfate esters, glycosides, aglycones, and O-methyl ethers. Around one third of these compounds are also known as food constituents and corresponded to polyphenols absorbed without further metabolism. Many ring-cleavage metabolites formed by gut microbiota were noted, mostly derived from hydroxycinnamates, flavanols and flavonols. Median maximum plasma concentrations (Cmax ) of all human metabolites were 0.09 ÎŒM and 0.32 ÎŒM when consumed from foods or dietary supplements respectively. Median time to reach maximum plasma concentration in humans (Tmax ) was 2.18 h. CONCLUSION: These data show the complexity of the polyphenol metabolome and the need to take into account biotransformations to understand in vivo bioactivities and the role of dietary polyphenols in health and disease. This article is protected by copyright. All rights reserved

    Assessing sprinkler irrigation uniformity using a ballistic simulation model

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    The definitive version is available at: http://ees.elsevier.com/agwatExperiments were performed in the Ebro Valley of Spain to provide the basis for the calibration and validation of a ballistic simulation model of sprinkler irrigation. The experiments included evaluations of isolated sprinklers and solid-sets. Two different sprinklers, two principal nozzle diameters and three operating pressures were considered in the experiments, which also covered the usual range of wind speeds in the study area. Model calibration served the objectives of predicting the Christiansen Coefficient of Uniformity (CU) and the water application pattern. The resulting standard error of CU estimation was 3.09 %. Tables of simulated uniformity were produced for the two sprinklers using different nozzle diameters, sprinkler spacings, operating pressures and wind speeds. These tables can be used for design and management purposes, identifying options leading to adequate irrigation uniformity. A simple simulation software has been produced and disseminated to assist irrigation professionals and farmers in decision making.This research was funded by the CONSI+D of the Government of AragĂłn (Spain) through grant P028/2000 and by the Plan Nacional de I+D+I of the Government of Spain through grant AGL2004-06675-C03/AGR.Peer reviewe

    Phenol-Explorer 2.0: a major update of the Phenol-Explorer database integrating data on polyphenol metabolism and pharmacokinetics in humans and experimental animals

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    Phenol-Explorer, launched in 2009, is the only comprehensive web-based database on the content in foods of polyphenols, a major class of food bioactives that receive considerable attention due to their role in the prevention of diseases. Polyphenols are rarely absorbed and excreted in their ingested forms, but extensively metabolized in the body, and until now, no database has allowed the recall of identities and concentrations of polyphenol metabolites in biofluids after the consumption of polyphenol-rich sources. Knowledge of these metabolites is essential in the planning of experiments whose aim is to elucidate the effects of polyphenols on health. Release 2.0 is the first major update of the database, allowing the rapid retrieval of data on the biotransformations and pharmacokinetics of dietary polyphenols. Data on 375 polyphenol metabolites identified in urine and plasma were collected from 236 peer-reviewed publications on polyphenol metabolism in humans and experimental animals and added to the database by means of an extended relational design. Pharmacokinetic parameters have been collected and can be retrieved in both tabular and graphical form. The web interface has been enhanced and now allows the filtering of information according to various criteria. Phenol-Explorer 2.0, which will be periodically updated, should prove to be an even more useful and capable resource for polyphenol scientists because bioactivities and health effects of polyphenols are dependent on the nature and concentrations of metabolites reaching the target tissues. The Phenol-Explorer database is publicly available and can be found online at http://www.phenol-explorer.eu. Database URL: http://www.phenol-explorer.eu

    Role of a Polyphenol-Rich Dietary Pattern in the Modulation of Intestinal Permeability in Older Subjects: The MaPLE Study

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    The inevitable rise of the proportion of people aged >65 years worldwide is paralleled by an increased burden of chronic diseases often associated with low-grade systemic inflammation. Recent findings suggest a link between inflammation and intestinal permeability (IP), a condition characterized by an impairment of intestinal barrier function which enables the translocation of dietary and bacterial factors into the blood activating the host immune system [1,2]. Dietary components can be significant modulators of inflammation and IP, and can also affect the intestinal microbial ecosystem. In the context of a diet-microbiota-IP axis in older subjects, dietary bioactives such as polyphenols may play a significant protective role due to their widely reported antioxidant and immunomodulatory properties and potential to regulate IP [3-6]

    Development and characterization of a microfluidic model of the tumour microenvironment

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    The physical microenvironment of tumours is characterized by heterotypic cell interactions and physiological gradients of nutrients, waste products and oxygen. This tumour microenvironment has a major impact on the biology of cancer cells and their response to chemotherapeutic agents. Despite this, most in vitro cancer research still relies primarily on cells grown in 2D and in isolation in nutrient- and oxygen-rich conditions. Here, a microfluidic device is presented that is easy to use and enables modelling and study of the tumour microenvironment in real-time. The versatility of this microfluidic platform allows for different aspects of the microenvironment to be monitored and dissected. This is exemplified here by real-time profiling of oxygen and glucose concentrations inside the device as well as effects on cell proliferation and growth, ROS generation and apoptosis. Heterotypic cell interactions were also studied. The device provides a live ‘window’ into the microenvironment and could be used to study cancer cells for which it is difficult to generate tumour spheroids. Another major application of the device is the study of effects of the microenvironment on cellular drug responses. Some data is presented for this indicating the device’s potential to enable more physiological in vitro drug screening
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