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21.
Schmit A Carol M Robert F Bontems P Houben JJ Van Gossum A Goldman M Mascart F 《European cytokine network》2002,13(3):298-305
BACKGROUND: Interleukin-10 (IL-10) is currently being extensively studied in clinical trials for the treatment of Crohn's disease (CD). Only marginal effects have, however, been reported, and the dose-response curve was bell-shaped contrasting with the reported data from in vitro experiments. AIM: To use another in vitro model to analyze the effect of rhIL-10 and rhIL-4 on the spontaneous mucosal TNF-alpha secretion in patients with CD, and to characterize the phenotype of the cells targeted by rhIL-10. METHODS: Non-inflamed colon biopsies from CD patients were cultured for 16 hours in presence of different concentrations of rhIL-10 or rhIL-4. The numbers of TNF-alpha-secreting cells among isolated lamina propria mononuclear cells (LPMNC) were estimated by Elispot. RESULTS: Both rhIL-10 and rhIL-4 down-regulate TNF-alpha secretion by LPMNC from CD patients, with a more pronounced effect with rhIL-10. These effects were closely linked to the cytokine concentrations used, with a bell-shaped dose-response curve. Residual TNF-alpha secretion, in the presence of optimal rhIL-10 concentration was mainly attributable to CD3+ T cells. In contrast, at higher rhIL-10 concentrations, CD3- cells contributed significantly to the TNF-alpha secretion. CONCLUSIONS: The in vitro model we used, demonstrates that IL-4, but mostly IL-10, efficiently suppresses TNF-alpha secretion in LPMNC from CD patients, with a dose-response curve similar to results obtained in vivo. Resistance at high rhIL-10 concentrations was associated with a change in the phenotype of TNF-alpha-secreting cells. 相似文献
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Elizabeth Zakszewski Brian Schmit Shekar Kurpad Matthew D. Budde 《Journal of visualized experiments : JoVE》2015,(98)
Magnetic resonance imaging (MRI) is the state of the art approach for assessing the status of the spinal cord noninvasively, and can be used as a diagnostic and prognostic tool in cases of disease or injury. Diffusion weighted imaging (DWI), is sensitive to the thermal motion of water molecules and allows for inferences of tissue microstructure. This report describes a protocol to acquire and analyze DWI of the rat cervical spinal cord on a small-bore animal system. It demonstrates an imaging setup for the live anesthetized animal and recommends a DWI acquisition protocol for high-quality imaging, which includes stabilization of the cord and control of respiratory motion. Measurements with diffusion weighting along different directions and magnitudes (b-values) are used. Finally, several mathematical models of the resulting signal are used to derive maps of the diffusion processes within the spinal cord tissue that provide insight into the normal cord and can be used to monitor injury or disease processes noninvasively. 相似文献
24.
Ikram Zaïdi Chantal Ebel Majdi Touzri Etienne Herzog Jean-Luc Evrard Anne Catherine Schmit Khaled Masmoudi Moez Hanin 《Plant molecular biology》2010,73(3):325-338
The regulation of plant signalling responses by Mitogen-Activated Protein Kinases (MAPKs)-mediated protein phosphorylation is well recognized. MAP kinase phosphatases (MKPs) are negative regulators of MAPKs in eukaryotes. We report here the identification and the characterization of TMKP1, the first wheat MKP (Triticum turgidum L. subsp. Durum). Expression profile analyses performed in two durum wheat cultivars showing a marked difference in salt and drought stress tolerance, revealed a differential regulation of TMKP1. Under salt and osmotic stress, TMKP1 is induced in the sensitive wheat variety and repressed in the tolerant one. A recombinant TMKP1 was shown to be an active phosphatase and capable to interact specifically with two wheat MAPKs (TMPK3 and TMPK6). In BY2 tobacco cells transiently expressing GFP::TMKP1, the fusion protein was localized into the nucleus. Interestingly, the deletion of the N-terminal non catalytic domain results in a strong accumulation of the truncated fusion protein in the cytoplasm. In addition, when expressed in BY2 cells, TMPK3 and TMPK6 fused to red fluorescent protein (RFP) were shown to be present predominantly in the nucleus. Surprisingly, when co-expressed with the N-terminal truncated TMKP1 fusion protein; both kinases are excluded from the nuclear compartment and accumulate in the cytoplasm. This strongly suggests that TMKP1 interacts in vivo with TMPK3 and TMPK6 and controls their subcellular localization. Taken together, our results show that the newly isolated wheat MKP might play an active role in modulating the plant cell responses to salt and osmotic stress responses. 相似文献
25.
Carol A. Shearer Enrique Descals Brigitte Kohlmeyer Jan Kohlmeyer Ludmila Marvanová David Padgett David Porter Huzefa A. Raja John P. Schmit Holly A. Thorton Hermann Voglymayr 《Biodiversity and Conservation》2007,16(1):49-67
Fungal biodiversity in freshwater, brackish and marine habitats was estimated based on reports in the literature. The taxonomic
groups treated were those with species commonly found on submerged substrates in aquatic habitats: Ascomycetes (exclusive of yeasts), Basidiomycetes, Chytridiomycetes, and the non-fungal Saprolegniales in the Class Oomycetes. Based on presence/absence data for a large number and variety of aquatic habitats, about 3,000 fungal species and 138 saprolegnialean
species have been reported from aquatic habitats. The greatest number of taxa comprise the Ascomycetes, including mitosporic taxa, and Chytridiomycetes. Taxa of Basidiomycetes are, for the most part, excluded from aquatic habitats. The greatest biodiversity for all groups occurs in temperate areas,
followed by Asian tropical areas. This pattern may be an artifact of the location of most of the sampling effort. The least
sampled geographic areas include Africa, Australia, China, South America and boreal and tropical regions worldwide. Some species
overlap occurs among terrestrial and freshwater taxa but little species overlap occurs among freshwater and marine taxa. We
predict that many species remain to be discovered in aquatic habitats given the few taxonomic specialists studying these fungi,
the few substrate types studied intensively, and the vast geographical area not yet sampled. 相似文献
26.
Seltzer V Janski N Canaday J Herzog E Erhardt M Evrard JL Schmit AC 《The Plant journal : for cell and molecular biology》2007,52(2):322-331
In higher plants, microtubules (MTs) are assembled in distinctive arrays in the absence of a defined organizing center. Three MT nucleation sites have been described: the nuclear surface, the cell cortex and cortical MT branch points. The Arabidopsis thaliana (At) genome contains putative orthologues encoding all the components of characterized mammalian nucleation complexes: gamma-tubulin and gamma-tubulin complex proteins GCP2 to GCP6. We have cloned the cDNA encoding AtGCP2, and show that gamma-tubulin, AtGCP2 and AtGCP3 are part of the same tandem affinity-purified complex and are present in a large membrane-associated complex. In addition, small soluble gamma-tubulin complexes of the size expected for a gamma-tubulin core complex are recruited to isolated nuclei. Using immunogold labelling, AtGCP3 is localized to both the nuclear envelope (NE) and the plasma membrane. To identify domains that could play a role in targeting complexes to these nucleation sites, truncated AtGCP2- and AtGCP3-green fluorescent protein fusion proteins were expressed in BY-2 cells. Several domains from AtGCP2 and AtGCP3 are capable of targeting fusions to the NE. We propose that regulated recruitment of soluble gamma-tubulin-containing complexes is responsible for nucleation at dispersed sites in plant cells and contributes to the formation and organization of the various MT arrays. 相似文献
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Diversification of sterol methyltransferase enzymes in plants and a role for β‐sitosterol in oriented cell plate formation and polarized growth 下载免费PDF全文
Masatoshi Nakamoto Anne‐Catherine Schmit Dimitri Heintz Hubert Schaller Daisaku Ohta 《The Plant journal : for cell and molecular biology》2015,84(5):860-874
Phytosterols are classified into C24‐ethylsterols and C24‐methylsterols according to the different C24‐alkylation levels conferred by two types of sterol methyltransferases (SMTs). The first type of SMT (SMT1) is widely conserved, whereas the second type (SMT2) has diverged in charophytes and land plants. The Arabidopsis smt2 smt3 mutant is defective in the SMT2 step, leading to deficiency in C24‐ethylsterols while the C24‐methylsterol pathway is unchanged. smt2 smt3 plants exhibit severe dwarfism and abnormal development throughout their life cycle, with irregular cell division followed by collapsed cell files. Preprophase bands are occasionally formed in perpendicular directions in adjacent cells, and abnormal phragmoplasts with mislocalized KNOLLE syntaxin and tubulin are observed. Defects in auxin‐dependent processes are exemplified by mislocalizations of the PIN2 auxin efflux carrier due to disrupted cell division and failure to distribute PIN2 asymmetrically after cytokinesis. Although endocytosis of PIN2–GFP from the plasma membrane (PM) is apparently unaffected in smt2 smt3, strong inhibition of the endocytic recycling is associated with a remarkable reduction in the level of PIN2–GFP on the PM. Aberrant localization of the cytoplasmic linker associated protein (CLASP) and microtubules is implicated in the disrupted endocytic recycling in smt2 smt3. Exogenous C24‐ethylsterols partially recover lateral root development and auxin distribution in smt2 smt3 roots. These results indicate that C24‐ethylsterols play a crucial role in division plane determination, directional auxin transport, and polar growth. It is proposed that the divergence of SMT2 genes together with the ability to produce C24‐ethylsterols were critical events to achieve polarized growth in the plant lineage. 相似文献
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Ledesma MC Jung-Hynes B Schmit TL Kumar R Mukhtar H Ahmad N 《Molecular medicine (Cambridge, Mass.)》2011,17(1-2):134-143
Various formulations of selenium and vitamin E, both essential human dietary components, have been shown to possess a therapeutic and preventive effect against prostate cancer. Fortuitous results of clinical trials also implied a risk-reduction effect of selenium and vitamin E supplements. The Selenium and Vitamin E Cancer Prevention Trial (SELECT), using oral selenium and vitamin E supplementation in disease-free volunteers, was designed to test a prostate cancer chemoprevention hypothesis. SELECT was terminated early because of both safety concerns and negative data for the formulations and doses given. Here, we review and discuss the studies done before and since the inception of SELECT, as well as the parameters of the trial itself. We believe that there is a lack of appropriate in vivo preclinical studies on selenium and vitamin E despite many promising in vitro studies on these agents. It seems that the most effective doses and formulations of these agents for prostate cancer chemoprevention have yet to be tested. Also, improved understanding of selenium and vitamin E biology may facilitate the discovery of these doses and formulations. 相似文献