554 research outputs found

    Artificial selection for timing of dispersal in predatory mites yields lines that differ in prey exploitation strategies

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    Dispersal is the main determinant of the dynamics and persistence of predator–prey metapopulations. When defining dispersal as a predator exploitation strategy, theory predicts the existence of a continuum of strategies: from some dispersal throughout the predator–prey interaction (the Milker strategy) to dispersal only after the prey had been exterminated (the Killer strategy). These dispersal strategies relate to differences in prey exploitation at the population level, with more dispersal leading to longer predator–prey interaction times and higher cumulative numbers of dispersing predators. In the predatory mite Phytoseiulus persimilis, empirical studies have shown genetic variation for prey exploitation as well as for the timing of aerial dispersal in the presence of prey. Here, we test whether artificial selection for lines that differ in timing of dispersal also results in these lines differing in prey exploitation. Six rounds of selection for early or late dispersal resulted in predator lines displaying earlier or later dispersal. Moreover, it resulted—at the population level—in predicted differences in the local predator–prey interaction time and in the cumulative numbers of dispersers in a population dynamics experiment. We pose that timing of dispersal is a heritable trait that can be selected in P. persimilis, which results in lines that show quantitative differences in local predator–prey dynamics. This opens ways to experimentally investigate the evolution of alternative prey exploitation strategies and to select for predator strains with prey exploitation strategies resulting in better biological control

    Mass spectrometry strategies to unveil modified aminophospholipids of biological interest

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    The biological functions of modified aminophospholipids (APL) have become a topic of interest during the last two decades, and distinct roles have been found for these biomolecules in both physiological and pathological contexts. Modifications of APL include oxidation, glycation, and adduction to electrophilic aldehydes, altogether contributing to a high structural variability of modified APL. An outstanding technique used in this challenging field is mass spectrometry (MS). MS has been widely used to unveil modified APL of biological interest, mainly when associated with soft ionization methods (electrospray and matrix-assisted laser desorption ionization) and coupled with separation techniques as liquid chromatography. This review summarizes the biological roles and the chemical mechanisms underlying APL modifications, and comprehensively reviews the current MS-based knowledge that has been gathered until now for their analysis. The interpretation of the MS data obtained by in vitro-identification studies is explained in detail. The perspective of an analytical detection of modified APL in clinical samples is explored, highlighting the fundamental role of MS in unveiling APL modifications and their relevance in pathophysiology.publishe

    Cryo-FIB Machining: An Alternative to TEM Cryo-Sections Cut with Diamonds?

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    Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7-August 11, 201

    Національна безпека України в епоху глобалізації

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    Розглядається сучасний проект Стратегії національної безпеки України “Україна в світі, що змінюється”, розроблений Національним інститутом стратегічних досліджень. Визначаються слабкі місця і невизначеності цієї стратегії. Проаналізовано реальний стан та перспективи впровадження цього проекту.In the article the modern is examined project of Strategy of national safety of Ukraine “Ukraine in the world that changes” worked out by the National institute of strategic. The weak locations and vaguenesses of this strategy are determined. An author analyses the real state and prospects of introduction of this project

    Training for the future

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    Aim The aim of this prospective study was to examine the association between behavioural problems and medical and psychological outcomes in clinically treated children and adolescents with asthma. Methods Patients (n=134) were recruited from two high-altitude asthma clinics in Switzerland and one asthma clinic in the Netherlands. Outcome measures were Asthma Control Test (ACT), Paediatric Asthma Quality of Life Questionnaire (PAQLQ(S)), forced expiratory volume in 1sec (FEV1) and fractional concentration of exhaled nitric oxide (FeNO). Parents completed the Child Behaviour Checklist (CBCL) (predictor variable). Data were collected at the start and end of treatment. Multiple regression analysis was used while adjusting for demographic variables, clinic and length of stay. Results More severe internalizing behavioural problems were associated with less improvement of total quality of life (t=2.26, p=0.03) and the domains symptoms (t=2.04, p=0.04) and emotions (t=2.3, p=0.02) after clinical treatment. Behavioural problems were not associated with a change of lung function measurements (FEV1 and FeNO) and asthma control (ACT) during treatment. Conclusion A focus of healthcare professionals on the treatment of internalizing behavioural problems may optimize the quality of life in clinically treated youth with asthma

    Methods to assess the effect of meat processing on viability of Toxoplasma gondii: towards replacement of mouse bioassay by in vitro testing

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    Consumption of meat containing viable tissue cysts is considered one of the main sources of human infection with Toxoplasma gondii. In contrast to fresh meat, raw meat products usually undergo processing, including salting and mixing with other additives such as sodium acetate and sodium lactate, which affects the viability of T. gondii. However, the experiments described in the literature are not always performed in line with the current processing methods applied in industry. It was our goal to study the effect of salting and additives according to the recipes used by industrial producers. Mouse or cat bioassay is the ‘gold standard’ to demonstrate the presence of viable T. gondii. However, it is costly, time consuming and for ethical reasons not preferred for large-scale studies. Therefore, we first aimed to develop an alternative for mouse bioassay that can be used to determine the effect of processing on the viability of T. gondii tissue cysts. The assays studied were (i) a cell culture method to determine the parasite’s ability to multiply, and (ii) a propidium monoazide (PMA) dye-based assay to selectively detect DNA from intact parasites. Processing experiments were performed with minced meat incubated for 20 h with low concentrations of NaCl, sodium lactate and sodium acetate. NaCl appeared to be the most effective ingredient with only one or two out of eight mice infected after inoculation with pepsin-digest of portions processed with 1.0, 1.2 and 1.6% NaCl. Results of preliminary experiments with the PMA-based method were inconsistent and did not sufficiently discriminate between live and dead parasites. In contrast, the cell culture method showed promising results, but further optimization is needed before it can replace or reduce the number of mouse bioassays needed. In future, standardised in vitro methods are necessary to allow more extensive testing of product-specific processing methods, thereby providing a better indication of the risk of T. gondii infection for consumers
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