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排序方式: 共有165条查询结果,搜索用时 15 毫秒
101.
Freek Cox Anna Roos Nicole Hafkemeijer Matthijs Baart Jeroen Tolboom Liesbeth Dekking Koert Stittelaar Jaap Goudsmit Katarina Rado?evi? Eirikur Saeland 《PloS one》2015,10(9)
There is a constant threat of zoonotic influenza viruses causing a pandemic outbreak in humans. It is virtually impossible to predict which virus strain will cause the next pandemic and it takes a considerable amount of time before a safe and effective vaccine will be available once a pandemic occurs. In addition, development of pandemic vaccines is hampered by the generally poor immunogenicity of avian influenza viruses in humans. An effective pre-pandemic vaccine is therefore required as a first line of defense. Broadening of the protective efficacy of current seasonal vaccines by adding an adjuvant may be a way to provide such first line of defense. Here we evaluate whether a seasonal trivalent virosomal vaccine (TVV) adjuvated with the saponin-based adjuvant Matrix-M (MM) can confer protection against avian influenza H5 and H7 virus strains in mice and ferrets. We demonstrate that mice were protected from death against challenges with H5N1 and H7N7, but that the protection was not complete as evidenced by severe clinical signs. In ferrets, protection against H7N9 was not observed. In contrast, reduced upper and lower respiratory tract viral loads and reduced lung pathology, was achieved in H5N1 challenged ferrets. Together these results suggest that, at least to some extent, Matrix-M adjuvated seasonal virosomal influenza vaccine can serve as an interim measure to decrease morbidity and mortality associated with a pandemic outbreak. 相似文献
102.
Robin van Velzen Niklas Wahlberg Marc S. M. Sosef Freek T. Bakker 《Biological journal of the Linnean Society. Linnean Society of London》2013,108(3):546-564
Extant clades may differ greatly in their species richness, suggesting differential rates of species diversification. Based on phylogenetic trees, it is possible to identify potential correlates of such differences. Here, we examine species diversification in a clade of 82 tropical African forest butterfly species (Cymothoe), together with its monotypic sister genus Harma. Our aim was to test whether the diversification of the Harma–Cymothoe clade correlates with end‐Miocene global cooling and desiccation, or with Pleistocene habitat range oscillations, both postulated to have led to habitat fragmentation. We first generated a species‐level phylogenetic tree for Harma and Cymothoe, calibrated within an absolute time scale, and then identified temporal and phylogenetic shifts in species diversification. Finally, we assessed correlations between species diversification and reconstructed global temperatures. Results show that, after the divergence of Harma and Cymothoe in the Miocene (15 Mya), net species diversification was low during the first 7 Myr. Coinciding with the onset of diversification of Cymothoe around 7.5 Mya, there was a sharp and significant increase in diversification rate, suggesting a rapid radiation, and correlating with a reconstructed period of global cooling and desiccation in the late Miocene, rather than with Pleistocene oscillations. Our estimated age of 4 Myr for a clade of montane species corresponds well with the uplift of the Eastern Arc Mountains where they occur. We conclude that forest fragmentation caused by changing climate in the late Miocene as well as the Eastern Arc Mountain uplift are both likely to have promoted species diversification in the Harma–Cymothoe clade. Cymothoe colonized Madagascar much later than most other insect lineages and, consequently, had less time available for diversification on the island. We consider the diversification of Cymothoe to be a special case compared with other butterfly clades studied so far, both in terms of its abrupt diversification rate increase and its recent occurrence (7 Myr). It is clear that larval host plant shift(s) cannot explain the difference in diversification between Cymothoe and Harma; however, such a shift(s) may have triggered differential diversification rates within Cymothoe. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, ●● , ●●–●●. 相似文献
103.
Freek G. Bouwman Mireille M.E. van Ginneken Jean-Paul Noben Erik Royackers Ellen de Graaf-Roelfsema Inge D. Wijnberg Johannes H. van der Kolk Edwin C.M. Mariman Eric van Breda 《Comparative biochemistry and physiology. Part D, Genomics & proteomics》2010,5(1):55-64
The major aim of the present study was to investigate the proteome of standardbred horses at different stages of training and intensified training. We searched for biomarkers using small skeletal muscle biopsies of live animals. 2D gel electrophoresis and mass spectrometry were successfully applied to investigate training-induced differential expression of equine muscle biopsy proteins. Despite the poor resolution of the equine genome and proteome, we were able to identify the proteins of 20 differential spots representing 16 different proteins. Evaluation of those proteins complies with adaptation of the skeletal muscle after normal training involving structural changes towards a higher oxidative capacity, an increased capacity to take up long-chain fatty acids, and to store energy in the form of glycogen. Intensified training leads to additional changed spots. Alpha-1-antitrypsin was found increased after intensified training but not after normal training. This protein may thus be considered as a marker for overtraining in horses and also linked to overtraining in human athletes. 相似文献
104.
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106.
L. Katie Crosley Susan J. Duthie Abigael C. Polley Freek G. Bouwman Carolin Heim Francis Mulholland Graham Horgan Ian T. Johnson Edwin C. Mariman Ruan M. Elliott Hannelore Daniel Baukje de Roos 《Genes & nutrition》2009,4(2):95-102
Blood cells and biofluid proteomics are emerging as a valuable tool to assess effects of interventions on health and disease. This study is aimed to assess the amount and variability of proteins from platelets, peripheral blood mononuclear cells (PBMC), plasma, urine and saliva from ten healthy volunteers for proteomics analysis, and whether protein yield is affected by prolonged fasting. Volunteers provided blood, saliva and morning urine samples once a week for 4 weeks after an overnight fast. Volunteers were fasted for a further 24 h after the fourth sampling before providing their final samples. Each 10 mL whole blood provided 400–1,500 μg protein from platelets, and 100–600 μg from PBMC. 30 μL plasma depleted of albumin and IgG provided 350–650 μg protein. A sample of morning urine provided 0.9–8.6 mg protein/dL, and a sample of saliva provided 70–950 μg protein/mL. None of these yields were influenced by the degree of fasting (overnight or 36 h). In conclusion, in contrast to the yields from plasma, platelets and PBMC, the protein yields of urine and saliva samples were highly variable within and between subjects. Certain disease conditions may cause higher or lower PBMC counts and thus protein yields, or increased urinary protein levels. 相似文献
107.
Joost M. Woltering Freek J. Vonk Nabila Bardine Ioana L. Tuduce Walter Knöchel Antony J. Durston 《Developmental biology》2009,332(1):82-89
It is generally assumed that the characteristic deregionalized body plan of species with a snake-like morphology evolved through a corresponding homogenization of Hox gene expression domains along the primary axis. Here, we examine the expression of Hox genes in snake embryos and show that a collinear pattern of Hox expression is retained within the paraxial mesoderm of the trunk. Genes expressed at the anterior and most posterior, regionalized, parts of the skeleton correspond to the expected anatomical boundaries. Unexpectedly however, also the dorsal (thoracic), homogenous rib-bearing region of trunk, is regionalized by unconventional gradual anterior limits of Hox expression that are not obviously reflected in the skeletal anatomy. In the lateral plate mesoderm we also detect regionalized Hox expression yet the forelimb marker Tbx5 is not restricted to a rudimentary forelimb domain but is expressed throughout the entire flank region. Analysis of several Hox genes in a caecilian amphibian, which convergently evolved a deregionalized body plan, reveals a similar global collinear pattern of Hox expression. The differential expression of posterior, vertebra-modifying or even rib-suppressing Hox genes within the dorsal region is inconsistent with the homogeneity in vertebral identity. Our results suggest that the evolution of a deregionalized, snake-like body involved not only alterations in Hox gene cis-regulation but also a different downstream interpretation of the Hox code. 相似文献
108.
Cerebellar high-frequency oscillations have been observed for many decades, but their underlying mechanisms have remained enigmatic. In this issue of Neuron, two papers indicate that specific intrinsic mechanisms in the cerebellar cortex contribute to the generation of these oscillations. Middleton et al. show that GABA(A) receptor activation and nonchemical transmission are required for nicotine-dependent oscillations at 30-80 Hz and 80-160 Hz, respectively, while de Solages et al. provide evidence that recurrent inhibition by Purkinje cells is essential for oscillations around 200 Hz. 相似文献
109.
Freek Braadbaart 《Vegetation History and Archaeobotany》2008,17(1):155-166
Modern Triticum dicoccum and Triticum aestivum grains, with and without glumes, were subjected to experimental carbonisation under anoxic conditions. Experimental variables
were the presence or absence of glumes, temperature, exposure time and heating rate. The maximum temperature was 600°C, the
time of exposure was 60 min and the heating rate between 1 and 100°C/min. Length, width, area, mass loss and reflectance of
uncarbonised and carbonised grains were measured as a function of the variables. The main effects of charring are an increase
in width, decrease in length and formation of protrusions. Reflectance measurements allow for the determination of the temperature
at which carbonisation occurred. The occurrence of protrusions on the pericarp, longitudinal imprints in the pericarp and
concave flanks are observed and discussed. The calculated shape factor 100L/W is a useful tool for distinguishing between T. dicoccum and T. aestivum grains in samples that contain at least thirty specimens, but for single grains this method is problematic. 相似文献
110.
In this ‘perspectives’ article, we share experiences gained from the century-old Kruger National Park (KNP) in South Africa
to illustrate the dynamic complexity of biophysical and socio-political systems, the interactions that occur between them,
and the consequences for ecosystem-scale functions and resources and for their management. As in KNP, the social-ecological
milieu surrounding many national parks and protected areas is changing rapidly. There will be significant managerial adjustments
as human populations grow and the needs for resources accelerate. The changes, driven largely by global-scale environmental
shifts as well as by new knowledge, are intimately intertwined with evolving societal perceptions, values, and expectations.
Many KNP resource-related issues of the past century originated more internally and were largely environmental, whereas the
emerging issues are more external and largely social. Here, we illustrate how interrelated scientific and managerial advances
in integrating biophysical and social systems are acting to conserve and rehabilitate resources within KNP, and to aid in
their conservation. Where appropriate, we relate these advances to similar examples in the region or other protected areas
in the world. Strategies to address emerging issues are identified and discussed—and their combined effects on resource conservation
and management are evaluated. In our experience the approach to conservation within KNP has been successful, despite well-intended
but damaging management actions in the past. We believe that the perceived success stems from a willingness to continually
incorporate new knowledge into management, to foster close working and personal associations among scientists, managers, and
rangers, to acquire an intimate knowledge and understanding of the social-ecological system by the administrators as well
as by the staff, and to be actively ‘forward’ thinking in an increasingly complex and uncertain world. We accept that many
decisions taken today will be challenged by future managers and scientists, and we expect that some will be found wanting
as emerging knowledge and continued learning shape future decisions. Further, evolving political, social, and environmental
contexts may mean that protected areas will need to be managed in different ways. Therefore, we emphasize the importance of
minimizing the permanency and impact of decisions so that today’s actions do not compromise future decisions when meaningful
changes need to be made.
相似文献
Robert J. NaimanEmail: |