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排序方式: 共有828条查询结果,搜索用时 31 毫秒
31.
Andreas Grahnert Tina Richter Daniel Piehler Maria Eschke Bianca Schulze Uwe Müller Martina Protschka Gabriele K?hler Robert Sabat Frank Brombacher Gottfried Alber 《PloS one》2014,9(1)
Cryptococcus neoformans is an opportunistic fungal pathogen that causes lung inflammation and meningoencephalitis in immunocompromised people. Previously we showed that mice succumb to intranasal infection by induction of pulmonary interleukin (IL)-4Rα–dependent type 2 immune responses, whereas IL-12-dependent type 1 responses confer resistance. In the experiments presented here, IL-4Rα−/− mice unexpectedly show decreased fungal control early upon infection with C. neoformans, whereas wild-type mice are able to control fungal growth accompanied by enhanced macrophage and dendritic cell recruitment to the site of infection. Lower pulmonary recruitment of macrophages and dendritic cells in IL-4Rα−/− mice is associated with reduced pulmonary expression of CCL2 and CCL20 chemokines. Moreover, IFN-γ and nitric oxide production are diminished in IL-4Rα−/− mice compared to wild-type mice. To directly study the potential mechanism(s) responsible for reduced production of IFN-γ, conventional dendritic cells were stimulated with C. neoformans in the presence of IL-4 which results in increased IL-12 production and reduced IL-10 production. Together, a beneficial role of early IL-4Rα signaling is demonstrated in pulmonary cryptococcosis, which contrasts with the well-known IL-4Rα-mediated detrimental effects in the late phase. 相似文献
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33.
YidC, an assembly site for polytopic Escherichia coli membrane proteins located in immediate proximity to the SecYE translocon and lipids 总被引:2,自引:0,他引:2
Konstanze Beck Gottfried Eisner Dorothea Trescher Ross E. Dalbey Josef Brunner Matthias Müller 《EMBO reports》2001,2(8):709-714
Like its mitochondrial homolog Oxa1p, the inner membrane protein YidC of Escherichia coli is involved in the integration of membrane proteins. We have analyzed individual insertion steps of the polytopic E. coli membrane protein MtlA targeted as ribosome-nascent chain complexes to inner membrane vesicles. YidC can accommodate at least the first two transmembrane segments of MtlA at the protein lipid interface and retain them even though the length of the nascent chain would amply allow insertion into membrane lipids. An even longer insertion intermediate of MtlA is described that still has the first transmembrane helix bound to YidC while the third contacts SecE and YidC during integration. Our findings suggest that YidC forms a contiguous integration unit with the SecYE translocon and functions as an assembly site for polytopic membrane proteins mediating the formation of helix bundles prior to their release into the membrane lipids. 相似文献
34.
Frederike Behn Stephan Michels Stephanie Ler Gottfried Blaschke 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,755(1-2)
A sensitive capillary electrophoretic method for the determination of carvedilol enantiomers in 100 μl of human plasma has been developed and validated. Carvedilol and the internal standard carazolol are isolated from plasma samples by liquid–liquid extraction using diethylether. A sensitive and selective detection is provided by helium–cadmium laser-induced fluorescence. The total analysis time is 17.5 min, about 30 min are needed for the sample preparation. The linearity of the assay ranges from 1.56 to 50 ng/ml per carvedilol enantiomer. The limits of quantification (LOQ) for the carvedilol enantiomers in 100 μl of human plasma are 1.56 ng/ml. The inter-day accuracy for R-carvedilol is between 95.8 and 103% (104% at LOQ) and for S-carvedilol between 97.1 and 103% (107% at LOQ); the inter-day precision values are between 3.81 and 8.64% (10.9% at LOQ) and between 5.47 and 7.86% (7.91% at LOQ) for R- and S-carvedilol, respectively. The small sample volume needed is especially advantageous for the application in clinical studies in pediatric patients. As an application of the assay concentration/time profiles of the carvedilol enantiomers in a 5-year-old patient receiving a test dose of 0.09 mg/kg carvedilol are reported. 相似文献
35.
Biochemical Characterization of Fungal Phytases (myo-Inositol Hexakisphosphate Phosphohydrolases): Catalytic Properties 总被引:15,自引:0,他引:15 下载免费PDF全文
Markus Wyss Roland Brugger Alexandra Kronenberger Roland Rmy Rachel Fimbel Gottfried Oesterhelt Martin Lehmann Adolphus P. G. M. van Loon 《Applied microbiology》1999,65(2):367-373
Supplementation with phytase is an effective way to increase the availability of phosphorus in seed-based animal feed. The biochemical characteristics of an ideal phytase for this application are still largely unknown. To extend the biochemical characterization of wild-type phytases, the catalytic properties of a series of fungal phytases, as well as Escherichia coli phytase, were determined. The specific activities of the fungal phytases at 37°C ranged from 23 to 196 U · (mg of protein)−1, and the pH optima ranged from 2.5 to 7.0. When excess phytase was used, all of the phytases were able to release five phosphate groups of phytic acid (myo-inositol hexakisphosphate), which left myo-inositol 2-monophosphate as the end product. A combination consisting of a phytase and Aspergillus niger pH 2.5 acid phosphatase was able to liberate all six phosphate groups. When substrate specificity was examined, the A. niger, Aspergillus terreus, and E. coli phytases were rather specific for phytic acid. On the other hand, the Aspergillus fumigatus, Emericella nidulans, and Myceliophthora thermophila phytases exhibited considerable activity with a broad range of phosphate compounds, including phenyl phosphate, p-nitrophenyl phosphate, sugar phosphates, α- and β-glycerophosphates, phosphoenolpyruvate, 3-phosphoglycerate, ADP, and ATP. Both phosphate liberation kinetics and a time course experiment in which high-performance liquid chromatography separation of the degradation intermediates was used showed that all of the myo-inositol phosphates from the hexakisphosphate to the bisphosphate were efficiently cleaved by A. fumigatus phytase. In contrast, phosphate liberation by A. niger or A. terreus phytase decreased with incubation time, and the myo-inositol tris- and bisphosphates accumulated, suggesting that these compounds are worse substrates than phytic acid is. To test whether broad substrate specificity may be advantageous for feed application, phosphate liberation kinetics were studied in vitro by using feed suspensions supplemented with 250 or 500 U of either A. fumigatus phytase or A. niger phytase (Natuphos) per kg of feed. Initially, phosphate liberation was linear and identical for the two phytases, but considerably more phosphate was liberated by the A. fumigatus phytase than by the A. niger phytase at later stages of incubation. 相似文献
36.
37.
An alternative scheme for selective water excitation is proposed. The pulse sequence saturates the resonances from the solute, allowing the observation of water-solute NOEs with low artifact levels. The water resonance is subsequently excited by a relatively non-selective 90° pulse. The scheme is compared to other selective water excitation schemes. 2D NOE-NOESY and ROE-NOESY pulse sequences are proposed which afford high sensitivity by efficient water excitation and flip-back by radiation damping, yet allow the use of short mixing times for the buildup of water-solute NOEs. 相似文献
38.
Neural control of mechanical ventilation in respiratory failure 总被引:9,自引:0,他引:9
Sinderby C Navalesi P Beck J Skrobik Y Comtois N Friberg S Gottfried SB Lindström L 《Nature medicine》1999,5(12):1433-1436
39.
Markus Düchler Fritz Schmoll Franz Pfneisl Gottfried Brem Karl Schellander 《Biology of the cell / under the auspices of the European Cell Biology Organization》1998,90(2):199-205
We have established three independent ovine mammary epithelial cell lines which arose from primary cultures of ovine mammary epithelial cells by spontaneous immortalization. One of them, OMEC II, was characterised in greater detail. The cells grow rapidly on plastic dishes in medium containing 10% FCS without any requirement for additional growth factors or hormones. Immunofluorescence staining of this cell line showed expression of cytokeratin (46 kDa) and ZO-1, a tight-junction associated protein, but negative immunostaining for an anti-vimentin antibody. In confluent cell monolayers ‘domes’ became visible indicating the development of a polarised phenotype and the ability of directed secretion. When grown in collagen gels typical ducts with end-buds were observed. Treatment with lactogenic hormones increased the frequency of dome formation, but no expression of β-lactoglobulin was found. To our knowledge this is the first report on an ovine mammary epithelial cell line. 相似文献
40.
Karin G. Michels-Rautenstrauss Christian Y. Mardin Wido M. Budde Thomas Liehr J. Polansky Thai Nguyen Vincent Timmerman C. Van Broeckhoven Gottfried O. H. Naumann Rudolf A. Pfeiffer B. W. Rautenstrauss 《Human genetics》1998,102(1):103-106
Autosomal dominant juvenile open angle glaucoma (JOAG) is an early-onset form of primary open angle glaucoma (POAG), which
has been linked to chromosome 1q21–q31. Recently, mutations in the trabecular meshwork inducible glucocorticoid response gene
(TIGR), one of the candidate genes mapped in this region, were identified in glaucoma patients of several families. We screened
for mutations of the TIGR gene in two German families with JOAG and in 100 unselected sporadic cases of POAG. In the first
family we identified a Pro370Leu mutation and in the second family a Gly367Arg mutation cosegregating with the glaucoma phenotype.
No pathogenic mutation was found in 100 sporadic cases but a Tyr347Tyr polymorphism was found in two patients. Furthermore,
fluorescence in situ hybridization (FISH) analysis was used to map a TIGR-specific yeast artificial chromosome to 1q24.3–q25.2.
Received: 19 June 1997 / Accepted: 12 August 1997 相似文献