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91.
Stefan U. Weber Andreas Koch Jens Kankeleit Jens-Christian Schewe Ullrich Siekmann Frank Stüber Andreas Hoeft Stefan Schröder 《Apoptosis : an international journal on programmed cell death》2009,14(1):97-107
During therapeutic hyperbaric oxygenation lymphocytes are exposed to high partial pressures of oxygen. This study aimed to
analyze the mechanism of apoptosis induction by hyperbaric oxygen. For intervals of 0.5–4 h Jurkat-T-cells were exposed to
ambient air or oxygen atmospheres at 1–3 absolute atmospheres. Apoptosis was analyzed by phosphatidylserine externalization,
caspase-3 activation and DNA-fragmentation using flow cytometry. Apoptosis was already induced after 30 min of hyperbaric
oxygenation (HBO, P < 0.05). The death receptor Fas was downregulated. Inhibition of caspase-9 but not caspase-8 blocked apoptosis induction
by HBO. Hyperbaric oxygen caused a loss of mitochondrial membrane potential and caspase-9 induction. The mitochondrial pro-survival
protein Bcl-2 was upregulated, and antagonizing Bcl-2 function potentiated apoptosis induction by HBO. In conclusion, a single
exposure to hyperbaric oxygenation induces lymphocyte apoptosis by a mitochondrial and not a Fas-related mechanism. Regulation
of Fas and Bcl-2 may be regarded as protective measures of the cell in response to hyperbaric oxygen. 相似文献
92.
Ribosome display is a powerful tool for selecting and evolving protein functions through ligand-binding. Here, this in vitro system was used to perform selection based on the folding properties of proteins, independent of specific ligand-binding. The selection is based on two properties of misfolded proteins: (1) increased sensitivity to proteolysis and (2) greater exposure of hydrophobic area. By targeting these properties, we show that compactly folded and soluble proteins can be enriched over insoluble and random coil proteins. This approach may be especially useful for selection and evolution of folded proteins from random sequence libraries. 相似文献
93.
van Wezel GP König M Mahr K Nothaft H Thomae AW Bibb M Titgemeyer F 《Journal of molecular microbiology and biotechnology》2007,12(1-2):67-74
Members of the soil-dwelling prokaryotic genus Streptomyces are indispensable for the recycling of complex polysaccharides, and produce a wide range of natural products. Nutrient limitation is likely to be a major signal for the onset of their development, resulting in spore formation by specialized aerial hyphae. Streptomycetes grow on numerous carbon sources, which they utilize in a preferential manner. The main signaling pathway underlying this phenomenon is carbon catabolite repression, which in streptomycetes is totally dependent on the glycolytic enzyme glucose kinase (Glk). How Glk exerts this fascinating dual role (metabolic and regulatory) is still largely a mystery. We show here that while Glk is made constitutively throughout the growth of Streptomyces coelicolor A3(2), its catalytic activity is modulated in a carbon source-dependent manner: while cultures growing exponentially on glucose exhibit high Glk activity, mannitol- grown cultures show negligible activity. Glk activity was directly proportional to the amount of two Glk isoforms observed by Western blot analysis. The activity profile of GlcP, the major glucose permease, correlated very well with that of Glk. Our data are consistent with a direct interaction between Glk and GlcP, suggesting that a Glk-GlcP permease complex is required for efficient glucose transport by metabolic trapping. This is supported by the strongly reduced accumulation of glucose in glucose kinase mutants. A model to explain our data is presented. 相似文献
94.
Euskirchen P Skaftnesmo KO Huszthy PC Brekkå N Bjerkvig R Jacobs AH Miletic H 《Experimental cell research》2011,(20):2864-2873
The cell fate determinant NUMB orchestrates asymmetric cell division in flies and mammals and has lately been suggested to have a tumor suppressor function in breast and lung cancer. Here, we studied NUMB in the context of malignant gliomas. We used ectopic expression of NUMB in order to inhibit proliferation and induce differentiation in glioma cells by alteration of Notch, Hedgehog and p53 signaling. We found that NUMB is consistently expressed in glioma biopsies with predominance of NUMB2/4 isoforms as determined by isoform-specific real-time PCR and Western blotting. Upon lentiviral overexpression, in vitro proliferation rate and the grade of differentiation as assessed by morphology and expression of neural and glial markers remained unchanged. Orthotopic xenografts of NUMB-transduced human U87 glioma cells could be established in nude rats without impairing engraftment or causing significant changes in morphology based on magnetic resonance imaging (MRI). The previously reported alteration of Hedgehog and p53 signaling by NUMB could not be recapitulated in glioma cells. We thus show that in experimental gliomas, NUMB overexpression most likely does not exert a tumor suppressor function such as seen in epithelial cancers. 相似文献
95.
96.
Investigation of a Family with Autosomal Dominant Dilated Cardiomyopathy Defines a Novel Locus on Chromosome 2q14-q22 总被引:4,自引:0,他引:4 下载免费PDF全文
Martin Jung Imke Poepping Andreas Perrot Annette E. Ellmer Thomas F. Wienker Rainer Dietz André Reis Karl Josef Osterziel 《American journal of human genetics》1999,65(4):1068-1077
Dilated cardiomyopathy (DCM) is a leading cause of heart failure and the most frequent indication for heart transplantation in young patients. Probably >25% of DCM cases are of familial etiology. We report here genetic localization in a three-generation German family with 12 affected individuals with autosomal dominant familial DCM characterized by ventricular dilatation, impaired systolic function, and conduction disease. After exclusion of known DCM loci, we performed a whole-genome screen and detected linkage of DCM to chromosome 2q14-q22. Investigation of only affected individuals defines a 24-cM interval between markers D2S2224 and D2S2324; when unaffected individuals are also included, the critical region decreases to 11 cM between markers D2S2224 and D2S112, with a peak LOD score of 3.73 at recombination fraction 0 at D2S2339. The identification of an additional locus for familial autosomal dominant DCM underlines the genetic heterogeneity and may assist in the elucidation of the causes of this disease. 相似文献
97.
Gesslbauer B Poljak A Handwerker C Schüler W Schwendenwein D Weber C Lundberg U Meinke A Kungl AJ 《Proteomics》2012,12(6):845-858
The versatility of the surface of Borrelia, the causative agent of Lyme borreliosis, is very important in host-pathogen interactions allowing bacteria to survive in ticks and to persist in a mammalian environment. To identify the surface proteome of Borrelia, we have performed a large comparative proteomic analysis on the three most important pathogenic Borrelia species, namely B. burgdorferi (strain B31), B. afzelii (strain K78), and B. garinii (strain PBi). Isolation of membrane proteins was performed by using three different approaches: (i) a detergent-based fractionation of outer membrane proteins; (ii) a trypsin-based partial shedding of outer cell surface proteins; (iii) biotinylation of membrane proteins and preparation of the biotin-labelled fraction using streptavidin. Proteins derived from the detergent-based fractionation were further sub-fractionated by heparin affinity chromatography since heparin-like molecules play an important role for microbial entry into human cells. All isolated proteins were analysed using either a gel-based liquid chromatography (LC)-MS/MS technique or by two-dimensional (2D)-LC-MS/MS resulting in the identification of 286 unique proteins. Ninety seven of these were found in all three Borrelia species, representing potential targets for a broad coverage vaccine for the prevention of Lyme borreliosis caused by the different Borrelia species. 相似文献
98.
The maternal‐zygotic transition and zygotic activation of the Mnemiopsis leidyi genome occurs within the first three cleavage cycles 下载免费PDF全文
99.
We investigated a community of syntopically occurring horseshoe bats (Rhinolophus hipposideros, R. euryale, R. ferrumequinum) in southern Slovakia. The faecal pellets of these bat species were collected in the field and later analysed under a dissecting microscope. The three species studied are known to be very similar as far as their ecology, echolocation and preferred habitats are concerned, but they diverge significantly in their body sizes. In this study, all three species fed predominantly on moths [59–80 percentage frequency (%f); 87–95 percentage volume (%vol)], but their diet compositions differed in the size of individuals consumed. The smallest bat species (R. hipposideros) fed only on the smallest moths (%f = 59; %vol = 87), the medium-sized species (R. euryale) mainly on medium-sized moths (%f = 60; %vol = 74) and the largest one (R. ferrumequinum) especially on the largest moths (%f = 54; %vol = 89). Despite similar preferred habitat and the main prey category, the rates of trophic niche overlap were surprisingly low. The trophic niche percentage overlap was 7–31% (computed from %f data) and 1–20% (computed from %vol data), respectively and suggests an extraordinary importance of mere divergences of bats in their body sizes for trophic niche partitioning and stable species coexistence. 相似文献