排序方式: 共有63条查询结果,搜索用时 437 毫秒
31.
North African coastal lagoons are unique ecosystems that often suffer degradation due to human activities. Therefore, monitoring methods are required to identify stressors and assist with the management of these valuable and often understudied ecosystems. A synthetic indicator of water ecological quality would be desirable for regular monitoring of these ecosystems under pressure. In 2008 an optical procedure was developed and applied in Ghar El Melh, a Tunisian lagoon which has been increasingly impacted by pollutant loading, especially from agriculture. In situ hyperspectral irradiance was measured at several stations, from which the apparent optical properties (AOPs), namely the irradiance attenuation coefficient K(λ) and the reflectance ratio R(λ), were obtained in order to relate them to water composition, in terms of light-attenuating substances (LASs). The significant relationships observed between R and LAS values enabled the application of a hyperspectral optical classification, which effectively highlighted threatened sectors of the lagoon. The pattern of differing water quality across the lagoon system that was derived from the hyperspectral classification agreed well with that obtained from a conventional optical classification that included AOPs and LASs. We suggest that hyperspectral analysis and classification is a useful monitoring tool for the assessment of change in coastal lagoons, and perhaps also in other shallow-water ecosystems. 相似文献
32.
The transpiration rate of individual 6-day-old oat plants was forced to oscillate by cyclic sine-shaped changes in the leaf irradiance (frequency 2 cycles h?1, amplitude and average value 1.4 mW cm?2, red light 620–800 nm). By means of a specially designed cuvette with three chambers the transpiration rate from three different segments of the leaf could be measured simultaneously. The leaf segments were illuminated individually and the illumination on each leaf segment could be modulated independently. The experiments showed that there was a strong correlation between the transpiration rates from the different leaf segments, dependent on a coupling mechanism in the plant. The coupling phenomenon disappeared when the root system was eliminated or when the water potential of the root medium was lowered. It was experimentally shown that CO2 diffusion in the leaf could not be the primary cause for the coupling. Therefore the stomatal dependence on the leaf water potential was considered the most probable reason for the coupling. The frequency of the forcing light cycles could be linearly changed during an experiment and this swept-frequency technique was used to obtain a frequency response of one single oat plant. The technique made it also possible to study the strength of the coupling between different leaf segments. 相似文献
33.
Li Y Shan F Wu JM Wu GS Ding J Xiao D Yang WY Atassi G Léonce S Caignard DH Renard P 《Bioorganic & medicinal chemistry letters》2001,11(1):5-8
Modification of artemisinin structure led us to the discovery of a novel class of antitumor compounds. These artemisinin derivatives containing cyano and aryl groups showed potent antiproliferative effect in vitro against P388 and A549 cells. This activity was reflected in P388 murine leukemia by an accumulation of cells in G1 phase, and induction of apoptosis. 相似文献
34.
35.
Komarova AV Combredet C Meyniel-Schicklin L Chapelle M Caignard G Camadro JM Lotteau V Vidalain PO Tangy F 《Molecular & cellular proteomics : MCP》2011,10(12):M110.007443
RNA viruses exhibit small-sized genomes encoding few proteins, but still establish complex networks of interactions with host cell components to achieve replication and spreading. Ideally, these virus-host protein interactions should be mapped directly in infected cell culture, but such a high standard is often difficult to reach when using conventional approaches. We thus developed a new strategy based on recombinant viruses expressing tagged viral proteins to capture both direct and indirect physical binding partners during infection. As a proof of concept, we engineered a recombinant measles virus (MV) expressing one of its virulence factors, the MV-V protein, with a One-STrEP amino-terminal tag. This allowed virus-host protein complex analysis directly from infected cells by combining modified tandem affinity chromatography and mass spectrometry analysis. Using this approach, we established a prosperous list of 245 cellular proteins interacting either directly or indirectly with MV-V, and including four of the nine already known partners of this viral factor. These interactions were highly specific of MV-V because they were not recovered when the nucleoprotein MV-N, instead of MV-V, was tagged. Besides key components of the antiviral response, cellular proteins from mitochondria, ribosomes, endoplasmic reticulum, protein phosphatase 2A, and histone deacetylase complex were identified for the first time as prominent targets of MV-V and the critical role of the later protein family in MV replication was addressed. Most interestingly, MV-V showed some preferential attachment to essential proteins in the human interactome network, as assessed by centrality and interconnectivity measures. Furthermore, the list of MV-V interactors also showed a massive enrichment for well-known targets of other viruses. Altogether, this clearly supports our approach based on reverse genetics of viruses combined with high-throughput proteomics to probe the interaction network that viruses establish in infected cells. 相似文献
36.
Grégory Caignard Gabriel A. Leiva-Torres Michael Leney-Greene Benoit Charbonneau Anne Dumaine Nassima Fodil-Cornu Michal Pyzik Pablo Cingolani Jeremy Schwartzentruber Jeremy Dupaul-Chicoine Huaijian Guo Maya Saleh André Veillette Marc Lathrop Mathieu Blanchette Jacek Majewski Angela Pearson Silvia M. Vidal 《PLoS pathogens》2013,9(9)
Herpes simplex encephalitis (HSE) is a lethal neurological disease resulting from infection with Herpes Simplex Virus 1 (HSV-1). Loss-of-function mutations in the UNC93B1, TLR3, TRIF, TRAF3, and TBK1 genes have been associated with a human genetic predisposition to HSE, demonstrating the UNC93B-TLR3-type I IFN pathway as critical in protective immunity to HSV-1. However, the TLR3, UNC93B1, and TRIF mutations exhibit incomplete penetrance and represent only a minority of HSE cases, perhaps reflecting the effects of additional host genetic factors. In order to identify new host genes, proteins and signaling pathways involved in HSV-1 and HSE susceptibility, we have implemented the first genome-wide mutagenesis screen in an in vivo HSV-1 infectious model. One pedigree (named P43) segregated a susceptible trait with a fully penetrant phenotype. Genetic mapping and whole exome sequencing led to the identification of the causative nonsense mutation L3X in the Receptor-type tyrosine-protein phosphatase C gene (PtprcL3X), which encodes for the tyrosine phosphatase CD45. Expression of MCP1, IL-6, MMP3, MMP8, and the ICP4 viral gene were significantly increased in the brain stems of infected PtprcL3X mice accounting for hyper-inflammation and pathological damages caused by viral replication. PtprcL3X mutation drastically affects the early stages of thymocytes development but also the final stage of B cell maturation. Transfer of total splenocytes from heterozygous littermates into Ptprc
L3X mice resulted in a complete HSV-1 protective effect. Furthermore, T cells were the only cell population to fully restore resistance to HSV-1 in the mutants, an effect that required both the CD4+ and CD8+ T cells and could be attributed to function of CD4+ T helper 1 (Th1) cells in CD8+ T cell recruitment to the site of infection. Altogether, these results revealed the CD45-mediated T cell function as potentially critical for infection and viral spread to the brain, and also for subsequent HSE development. 相似文献
37.
Basséne CE Suzenet F Hennuyer N Staels B Caignard DH Dacquet C Renard P Guillaumet G 《Bioorganic & medicinal chemistry letters》2006,16(17):4528-4532
In order to define new PPARbeta/delta ligands, SAR study on the selective PPARbeta/delta activator L-165,041 led to the identification of one key functional group for selective PPARbeta/delta activation. Furthermore, taking advantage of SAR studies done elsewhere on the most selective PPARbeta/delta ligand GW501516, the conception of new ligands showing good affinity for PPARbeta/delta is reported. Finally, synthesis and biological evaluation of pyridine analogues have shown the benefical effect of the pyridine ring on the PPARbeta/delta subtype selectivity. 相似文献
38.
Julien Pothlichet Anne Burtey Andriy V. Kubarenko Gregory Caignard Brigitte Solhonne Frédéric Tangy Meriem Ben-Ali Lluis Quintana-Murci Andrea Heinzmann Jean-Daniel Chiche Pierre-Olivier Vidalain Alexander N. R. Weber Michel Chignard Mustapha Si-Tahar 《PloS one》2009,4(10)
Background
RIG-I is a pivotal receptor that detects numerous RNA and DNA viruses. Thus, its defectiveness may strongly impair the host antiviral immunity. Remarkably, very little information is available on RIG-I single-nucleotide polymorphisms (SNPs) presenting a functional impact on the host response.Methodology/Principal Findings
Here, we studied all non-synonymous SNPs of RIG-I using biochemical and structural modeling approaches. We identified two important variants: (i) a frameshift mutation (P229fs) that generates a truncated, constitutively active receptor and (ii) a serine to isoleucine mutation (S183I), which drastically inhibits antiviral signaling and exerts a down-regulatory effect, due to unintended stable complexes of RIG-I with itself and with MAVS, a key downstream adapter protein.Conclusions/Significance
Hence, this study characterized P229fs and S183I SNPs as major functional RIG-I variants and potential genetic determinants of viral susceptibility. This work also demonstrated that serine 183 is a residue that critically regulates RIG-I-induced antiviral signaling. 相似文献39.
Cécile Parmenon Jérôme Guillard Daniel-Henri Caignard Nathalie Hennuyer Bart Staels Valérie Audinot-Bouchez Jean-Albert Boutin Catherine Dacquet Alain Ktorza Marie-Claude Viaud-Massuard 《Bioorganic & medicinal chemistry letters》2009,19(10):2683-2687
Type-2 diabetes (T2D) is a complex metabolic disease characterized by insulin resistance in the liver and peripheral tissues accompanied by a deficiency in pancreatic β-cells. Since their discovery, three subtypes of peroxisome proliferator activated receptors have been identified, namely PPARα, PPARγ and PPARβ/(δ). In this study, we were interested in designing novel PPARγ selective agonists and/or dual PPARα/γ agonists. Based on the typical topology of synthetic PPAR agonists, we focused our design approach on using 4,4-dimethyl-1,2,3,4-tetrahydroquinoline as a novel cyclic scaffold with oxime and acidic head group structural variations. 相似文献
40.
Giuliani M Giron-Michel J Negrini S Vacca P Durali D Caignard A Le Bousse-Kerdiles C Chouaib S Devocelle A Bahri R Durrbach A Taoufik Y Ferrini S Croce M Mingari MC Moretta L Azzarone B 《PloS one》2008,3(5):e2241