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671.
672.
Pierre Mariotte Charlotte Vandenberghe Claire Meugnier Pierre Rossi Richard D. Bardgett Alexandre Buttler 《Perspectives in Plant Ecology, Evolution and Systematics》2013,15(2):77-85
Despite their low relative abundance, subordinate plant species may have larger impacts on ecosystem functioning than expected, but their role in plant communities remains poorly understood. The aim of this study was to test how subordinate plant species influence the functioning of a species-rich semi-natural grasslands. A plant removal experiment was set-up in the mountain grasslands of the Jura Mountains (Switzerland) to test the impact of subordinate plant species on soil microbial communities and ecosystem functioning. The experiment included three treatments: removal of all subordinate species, partial biomass removal of dominant species, and a no biomass removal control. After 2 years of treatments, we determined soil microbial community (bacteria and mycorrhizal fungi) by T-RFLP analysis and measured litter decomposition, soil respiration, soil inorganic nitrogen (DIN) availability and throughout above-ground biomass production as measures of ecosystem function. The removal of subordinate plant species strongly affected bacterial and weakly influenced mycorrhizal fungi communities and decreased rates of plant litter decomposition, soil respiration and DIN availability with larger effects than the partial loss of dominant biomass. The removal of subordinate plant species did not modify plant community structure, but it did reduce total above-ground biomass production compared to the control plots. Collectively, our findings indicate that the loss of subordinate species can have significant consequences for soil microbial communities and ecosystem functions, suggesting that subordinate species are important drivers of ecosystem properties. 相似文献
673.
674.
Alok Kumar Gupta Vikram Singh Gaur Sanjay Gupta Anil Kumar 《Functional & integrative genomics》2013,13(2):179-190
In order to understand the molecular basis of high nitrogen use efficiency of finger millet, five genes (EcHNRT2, EcLNRT1, EcNADH-NR, EcGS, and EcFd-GOGAT) involved in nitrate uptake and assimilation were isolated using conserved primer approaches. Expression profiles of these five genes along with the previously isolated EcDof1 was studied under increased KNO3 concentrations (0.15 to 1,500 μM) for 2 h as well as at 1.5 μM for 24 h in the roots and shoots of 25 days old nitrogen deprived two contrasting finger millet genotypes (GE-3885 and GE-1437) differing in grain protein content (13.76 and 6.15 %, respectively). Time kinetics experiment revealed that, all the five genes except EcHNRT2 in the leaves of GE-3885 were induced within 30 min of nitrate exposure indicating that there might be a greater nitrogen deficit in leaves and therefore quick transportation of nitrate signals to the leaves. Exposing the plants to increasing nitrate concentrations for 2 h showed that in roots of GE-3885, NR was strongly induced while GS was repressed; however, the pattern was found to be reversed in leaves of GE-1437 indicating that in GE-3885, most of the nitrate might be reduced in the roots but assimilated in leaves and vice-versa. Furthermore, compared with the low-protein genotype, expression of HNRT2 was strongly induced in both roots and shoots of high-protein genotype at the least nitrate concentration supplied. This further indicates that GE-3885 is a quick sensor of nitrogen compared with the low-protein genotype. Furthermore, expression of EcDof1 was also found to overlap the expression of NR, GS, and GOGAT indicating that Dof1 probably regulates the expression of these genes under different conditions by sensing the nitrogen fluctuations around the root zone. 相似文献
675.
Julie Blaising Pierre L. Lévy Claire Gondeau Capucine Phelip Mihayl Varbanov Elodie Teissier Florence Ruggiero Stephen J. Polyak Nicholas H. Oberlies Tijana Ivanovic Eve‐Isabelle Pécheur 《Cellular microbiology》2013,15(11):1866-1882
Hepatitis C virus (HCV) is a global health concern infecting 170 million people worldwide. Previous studies indicate that the extract from milk thistle known as silymarin and its main component silibinin inhibit HCV infection. Here we investigated the mechanism of anti‐HCV action ofsilymarin‐derived compounds at the molecular level. By using live‐cell confocal imaging, single particle tracking, transmission electron microscopy and biochemical approaches on HCV‐infected human hepatoma cells and primary hepatocytes, we show that silibinin potently inhibits HCV infection and hinders HCV entry by slowing down trafficking through clathrin‐coated pits and vesicles. Detailed analyses revealed that silibinin altered the formation of both clathrin‐coated pits and vesicles in cells and caused abnormal uptake and trafficking of transferrin, a well‐known cargo of the clathrin endocytic pathway. Silibinin also inhibited infection by other viruses that enter cells by clathrin‐mediated endocytosis including reovirus, vesicular stomatitis and influenza viruses. Our study demonstrates that silibinin inhibits HCV early steps of infection by affecting endosomal trafficking of virions. It provides new insights into the molecular mechanisms of action of silibinin against HCV entry and also suggests that silibinin is a potential broad‐spectrum antiviral therapy. 相似文献
676.
Romain Philippe Etienne Paux Isabelle Bertin Pierre Sourdille Fréderic Choulet Christel Laugier Hana ?imková Jan ?afá? Arnaud Bellec Sonia Vautrin Zeev Frenkel Federica Cattonaro Federica Magni Simone Scalabrin Mihaela M Martis Klaus FX Mayer Abraham Korol Hélène Bergès Jaroslav Dole?el Catherine Feuillet 《Genome biology》2013,14(6):R64
Background
As for other major crops, achieving a complete wheat genome sequence is essential for the application of genomics to breeding new and improved varieties. To overcome the complexities of the large, highly repetitive and hexaploid wheat genome, the International Wheat Genome Sequencing Consortium established a chromosome-based strategy that was validated by the construction of the physical map of chromosome 3B. Here, we present improved strategies for the construction of highly integrated and ordered wheat physical maps, using chromosome 1BL as a template, and illustrate their potential for evolutionary studies and map-based cloning.Results
Using a combination of novel high throughput marker assays and an assembly program, we developed a high quality physical map representing 93% of wheat chromosome 1BL, anchored and ordered with 5,489 markers including 1,161 genes. Analysis of the gene space organization and evolution revealed that gene distribution and conservation along the chromosome results from the superimposition of the ancestral grass and recent wheat evolutionary patterns, leading to a peak of synteny in the central part of the chromosome arm and an increased density of non-collinear genes towards the telomere. With a density of about 11 markers per Mb, the 1BL physical map provides 916 markers, including 193 genes, for fine mapping the 40 QTLs mapped on this chromosome.Conclusions
Here, we demonstrate that high marker density physical maps can be developed in complex genomes such as wheat to accelerate map-based cloning, gain new insights into genome evolution, and provide a foundation for reference sequencing. 相似文献677.
Elodie Lainey Alice Wolfromm Abdul Qader Sukkurwala Jean-Baptiste Micol Pierre Fenaux Lorenzo Galluzzi Oliver Kepp Guido Kroemer 《Cell cycle (Georgetown, Tex.)》2013,12(18):2978-2991
By means of an unbiased, automated fluorescence microscopy-based screen, we identified the epidermal growth factor receptor (EGFR) inhibitors erlotinib and gefitinib as potent enhancers of the differentiation of HL-60 acute myeloid leukemia (AML) cells exposed to suboptimal concentrations of vitamin A (all-trans retinoic acid, ATRA) or vitamin D (1α,25-hydroxycholecalciferol, VD). Erlotinib and gefitinib alone did not promote differentiation, yet stimulated the acquisition of morphological and biochemical maturation markers (including the expression of CD11b and CD14 as well as increased NADPH oxidase activity) when combined with either ATRA or VD. Moreover, the combination of erlotinib and ATRA or VD synergistically induced all the processes that are normally linked to terminal hematopoietic differentiation, namely, a delayed proliferation arrest in the G0/G1 phase of the cell cycle, cellular senescence, and apoptosis. Erlotinib potently inhibited the (auto)phosphorylation of mitogen-activated protein kinase 14 (MAPK14, best known as p38MAPK) and SRC family kinases (SFKs). If combined with the administration of ATRA or VD, the inhibition of p38MAPK or SFKs with specific pharmacological agents mimicked the pro-differentiation activity of erlotinib. These data were obtained with 2 distinct AML cell lines (HL-60 and MOLM-13 cells) and could be confirmed on primary leukemic blasts isolated from the circulation of AML patients. Altogether, these findings point to a new regimen for the treatment of AML, in which naturally occurring pro-differentiation agents (ATRA or VD) may be combined with EGFR inhibitors. 相似文献
678.
679.
Nicolas Rochereau Daniel Drocourt Eric Perouzel Vincent Pavot Pierre Redelinghuys Gordon D. Brown Gerard Tiraby Xavier Roblin Bernard Verrier Christian Genin Blaise Corthésy Stéphane Paul 《PLoS biology》2013,11(9)
Intestinal microfold (M) cells possess a high transcytosis capacity and are able to transport a broad range of materials including particulate antigens, soluble macromolecules, and pathogens from the intestinal lumen to inductive sites of the mucosal immune system. M cells are also the primary pathway for delivery of secretory IgA (SIgA) to the gut-associated lymphoid tissue. However, although the consequences of SIgA uptake by M cells are now well known and described, the mechanisms whereby SIgA is selectively bound and taken up remain poorly understood. Here we first demonstrate that both the Cα1 region and glycosylation, more particularly sialic acid residues, are involved in M cell–mediated reverse transcytosis. Second, we found that SIgA is taken up by M cells via the Dectin-1 receptor, with the possible involvement of Siglec-5 acting as a co-receptor. Third, we establish that transcytosed SIgA is taken up by mucosal CX3CR1+ dendritic cells (DCs) via the DC-SIGN receptor. Fourth, we show that mucosal and systemic antibody responses against the HIV p24-SIgA complexes administered orally is strictly dependent on the expression of Dectin-1. Having deciphered the mechanisms leading to specific targeting of SIgA-based Ag complexes paves the way to the use of such a vehicle for mucosal vaccination against various infectious diseases. 相似文献
680.