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排序方式: 共有927条查询结果,搜索用时 15 毫秒
31.
Kazima Saira Xudong Lin Jay V. DePasse Rebecca Halpin Alan Twaddle Timothy Stockwell Brian Angus Alessandro Cozzi-Lepri Marina Delfino Vivien Dugan Dominic E. Dwyer Matthew Freiberg Andrzej Horban Marcelo Losso Ruth Lynfield Deborah N. Wentworth Edward C. Holmes Richard Davey David E. Wentworth Elodie Ghedin 《Journal of virology》2013,87(14):8064-8074
Influenza virus defective interfering (DI) particles are naturally occurring noninfectious virions typically generated during in vitro serial passages in cell culture of the virus at a high multiplicity of infection. DI particles are recognized for the role they play in inhibiting viral replication and for the impact they have on the production of infectious virions. To date, influenza virus DI particles have been reported primarily as a phenomenon of cell culture and in experimentally infected embryonated chicken eggs. They have also been isolated from a respiratory infection of chickens. Using a sequencing approach, we characterize several subgenomic viral RNAs from human nasopharyngeal specimens infected with the influenza A(H1N1)pdm09 virus. The distribution of these in vivo-derived DI-like RNAs was similar to that of in vitro DIs, with the majority of the defective RNAs generated from the PB2 (segment 1) of the polymerase complex, followed by PB1 and PA. The lengths of the in vivo-derived DI-like segments also are similar to those of known in vitro DIs, and the in vivo-derived DI-like segments share internal deletions of the same segments. The presence of identical DI-like RNAs in patients linked by direct contact is compatible with transmission between them. The functional role of DI-like RNAs in natural infections remains to be established. 相似文献
32.
Sébastien Tisné Yann Serrand Liên Bach Elodie Gilbault Rachid Ben Ameur Hervé Balasse Roger Voisin David Bouchez Mylène Durand‐Tardif Philippe Guerche Gaël Chareyron Jérôme Da Rugna Christine Camilleri Olivier Loudet 《The Plant journal : for cell and molecular biology》2013,74(3):534-544
Increased phenotyping accuracy and throughput are necessary to improve our understanding of quantitative variation and to be able to deconstruct complex traits such as those involved in growth responses to the environment. Still, only a few facilities are known to handle individual plants of small stature for non‐destructive, real‐time phenotype acquisition from plants grown in precisely adjusted and variable experimental conditions. Here, we describe Phenoscope, a high‐throughput phenotyping platform that has the unique feature of continuously rotating 735 individual pots over a table. It automatically adjusts watering and is equipped with a zenithal imaging system to monitor rosette size and expansion rate during the vegetative stage, with automatic image analysis allowing manual correction. When applied to Arabidopsis thaliana, we show that rotating the pots strongly reduced micro‐environmental disparity: heterogeneity in evaporation was cut by a factor of 2.5 and the number of replicates needed to detect a specific mild genotypic effect was reduced by a factor of 3. In addition, by controlling a large proportion of the micro‐environmental variance, other tangible sources of variance become noticeable. Overall, Phenoscope makes it possible to perform large‐scale experiments that would not be possible or reproducible by hand. When applied to a typical quantitative trait loci (QTL) mapping experiment, we show that mapping power is more limited by genetic complexity than phenotyping accuracy. This will help to draw a more general picture as to how genetic diversity shapes phenotypic variation. 相似文献
33.
Guillaume Mas Elodie Crublet Olivier Hamelin Pierre Gans Jérôme Boisbouvier 《Journal of biomolecular NMR》2013,57(3):251-262
The specific protonation of valine and leucine methyl groups in proteins is typically achieved by overexpressing proteins in M9/D2O medium supplemented with either labeled α-ketoisovalerate for the labeling of the four prochiral methyl groups or with 2-acetolactate for the stereospecific labeling of the valine and leucine side chains. However, when these labeling schemes are applied to large protein assemblies, significant overlap between the correlations of the valine and leucine methyl groups occurs, hampering the analysis of 2D methyl-TROSY spectra. Analysis of the leucine and valine biosynthesis pathways revealed that the incorporation of labeled precursors in the leucine pathway can be inhibited by the addition of exogenous l-leucine-d10. We exploited this property to label stereospecifically the pro-R and pro-S methyl groups of valine with minimal scrambling to the leucine residues. This new labeling protocol was applied to the 468 kDa homododecameric peptidase TET2 to decrease the complexity of its NMR spectra. All of the pro-S valine methyl resonances of TET2 were assigned by combining mutagenesis with this innovative labeling approach. The assignments were transferred to the pro-R groups using an optimally labeled sample and a set of triple resonance experiments. This improved labeling scheme enables us to overcome the main limitation of overcrowding in the NMR spectra of prochiral methyl groups, which is a prerequisite for the site-specific measurement of the structural and dynamic parameters or for the study of interactions in very large protein assemblies. 相似文献
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35.
Elodie A. Courtois Kyle G. Dexter Charles Eliot Timothy Paine Didier Stien Julien Engel Christopher Baraloto Jérôme Chave 《Ecology and evolution》2016,6(9):2854-2864
Plant responses to natural enemies include formation of secondary metabolites acting as direct or indirect defenses. Volatile terpenes represent one of the most diverse groups of secondary metabolites. We aimed to explore evolutionary patterns of volatile terpene emission. We measured the composition of damage‐induced volatile terpenes from 202 Amazonian tree species, spanning the angiosperm phylogeny. Volatile terpenes were extracted with solid‐phase micro extraction and desorbed in a gas chromatography–mass spectrometry for compound identification. The chemical diversity of the terpene blend showed a strong phylogenetic signal as closely related species emitted a similar number of compounds. Closely related species also tended to have compositionally similar blends, although this relationship was weak. Meanwhile, the ability to emit a given compound showed no significant phylogenetic signal for 200 of 286 compounds, indicating a high rate of diversification in terpene synthesis and/or great variability in their expression. Three lineages (Magnoliales, Laurales, and Sapindales) showed exceptionally high rates of terpene diversification. Of the 70 compounds found in >10% of their species, 69 displayed significant correlated evolution with at least one other compound. These results provide insights into the complex evolutionary history of volatile terpenes in angiosperms, while highlighting the need for further research into this important class of compounds. 相似文献
36.
Increasing evidence suggests that nocturnal transpiration rate (TRN) is a non‐negligible contributor to global water cycles. Short‐term variation in nocturnal vapor pressure deficit (VPDN) has been suggested to be a key environmental variable influencing TRN. However, the long‐term effects of VPDN on plant growth and development remain unknown, despite recent evidence documenting long‐term effects of daytime VPD on plant anatomy, growth and productivity. Here we hypothesized that plant anatomical and functional traits influencing leaf and root hydraulics could be influenced by long‐term exposure to VPDN. A total of 23 leaf and root traits were examined on four wheat (Triticum aestivum) genotypes, which were subjected to two long‐term (30 day long) growth experiments where daytime VPD and daytime/nighttime temperature regimes were kept identical, with variation only stemming from VPDN, imposed at two levels (0.4 and 1.4 kPa). The VPDN treatment did not influence phenology, leaf areas, dry weights, number of tillers or their dry weights, consistently with a drought and temperature‐independent treatment. In contrast, vein densities, adaxial stomata densities, TRN and cuticular TR, were strongly increased following exposure to high VPDN. Simultaneously, whole‐root system xylem sap exudation and seminal root endodermis thickness were decreased, hypothetically indicating a change in root hydraulic properties. Overall these results suggest that plants ‘sense’ and adapt to variations in VPDN conditions over developmental scales by optimizing both leaf and root hydraulics. 相似文献
37.
Clinical,genetic and neuropathological findings in a series of 138 fetuses with a corpus callosum malformation
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Caroline Alby Valérie Malan Lucile Boutaud Maria Angela Marangoni Bettina Bessières Maryse Bonniere Amale Ichkou Nadia Elkhartoufi Nadia Bahi‐Buisson Pascale Sonigo Anne‐Elodie Millischer Sophie Thomas Yves Ville Michel Vekemans Férechté Encha‐Razavi Tania Attié‐Bitach 《Birth defects research. Part A, Clinical and molecular teratology》2016,106(1):36-46
38.
Alexis De Wever Karim Benzerara Margot Coutaud Graldine Caumes Mlanie Poinsot Friel Skouri‐Panet Thierry Laurent Elodie Duprat Muriel Gugger 《Geobiology》2019,17(6):676-690
Several species of cyanobacteria biomineralizing intracellular amorphous calcium carbonates (ACC) were recently discovered. However, the mechanisms involved in this biomineralization process and the determinants discriminating species forming intracellular ACC from those not forming intracellular ACC remain unknown. Recently, it was hypothesized that the intensity of Ca uptake (i.e., how much Ca was scavenged from the extracellular solution) might be a major parameter controlling the capability of a cyanobacterium to form intracellular ACC. Here, we tested this hypothesis by systematically measuring the Ca uptake by a set of 52 cyanobacterial strains cultured in the same growth medium. The results evidenced a dichotomy among cyanobacteria regarding Ca sequestration capabilities, with all strains forming intracellular ACC incorporating significantly more calcium than strains not forming ACC. Moreover, Ca provided at a concentration of 50 μM in BG‐11 was shown to be limiting for the growth of some of the strains forming intracellular ACC, suggesting an overlooked quantitative role of Ca for these strains. All cyanobacteria forming intracellular ACC contained at least one gene coding for a mechanosensitive channel, which might be involved in Ca influx, as well as at least one gene coding for a Ca2+/H+ exchanger and membrane proteins of the UPF0016 family, which might be involved in active Ca transport either from the cytosol to the extracellular solution or the cytosol toward an intracellular compartment. Overall, massive Ca sequestration may have an indirect role by allowing the formation of intracellular ACC. The latter may be beneficial to the growth of the cells as a storage of inorganic C and/or a buffer of intracellular pH. Moreover, high Ca scavenging by cyanobacteria biomineralizing intracellular ACC, a trait shared with endolithic cyanobacteria, suggests that these cyanobacteria should be considered as potentially significant geochemical reservoirs of Ca. 相似文献
39.
40.
The distribution of residues in a polypeptide sequence is a determinant of aggregation optimized by evolution
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Monsellier E Ramazzotti M de Laureto PP Tartaglia GG Taddei N Fontana A Vendruscolo M Chiti F 《Biophysical journal》2007,93(12):4382-4391
It has been shown that the propensity of a protein to form amyloid-like fibrils can be predicted with high accuracy from the knowledge of its amino acid sequence. It has also been suggested, however, that some regions of the sequences are more important than others in determining the aggregation process. Here, we have addressed this issue by constructing a set of “sequence scrambled” variants of the first 29 residues of horse heart apomyoglobin (apoMb1-29), in which the sequence was modified while maintaining the same amino acid composition. The clustering of the most amyloidogenic residues in one region of the sequence was found to cause a marked increase of the elongation rate (kagg) and a remarkable shortening of the lag phase (tlag) of the fibril growth, as determined by far-UV circular dichroism and thioflavin T fluorescence. We also show that taking explicitly into consideration the presence of aggregation-promoting regions in the predictive methods results in a quantitative agreement between the theoretical and observed kagg and tlag values of the apoMb1-29 variants. These results, together with a comparison between homologous segments from the family of globins, indicate the existence of a negative selection against the clustering of highly amyloidogenic residues in one or few regions of polypeptide sequences. 相似文献